1 // SPDX-License-Identifier: GPL-2.0-or-later
2 // SPI init/core code
3 //
4 // Copyright (C) 2005 David Brownell
5 // Copyright (C) 2008 Secret Lab Technologies Ltd.
6 
7 #include <linux/kernel.h>
8 #include <linux/device.h>
9 #include <linux/init.h>
10 #include <linux/cache.h>
11 #include <linux/dma-mapping.h>
12 #include <linux/dmaengine.h>
13 #include <linux/mutex.h>
14 #include <linux/of_device.h>
15 #include <linux/of_irq.h>
16 #include <linux/clk/clk-conf.h>
17 #include <linux/slab.h>
18 #include <linux/mod_devicetable.h>
19 #include <linux/spi/spi.h>
20 #include <linux/spi/spi-mem.h>
21 #include <linux/gpio/consumer.h>
22 #include <linux/pm_runtime.h>
23 #include <linux/pm_domain.h>
24 #include <linux/property.h>
25 #include <linux/export.h>
26 #include <linux/sched/rt.h>
27 #include <uapi/linux/sched/types.h>
28 #include <linux/delay.h>
29 #include <linux/kthread.h>
30 #include <linux/ioport.h>
31 #include <linux/acpi.h>
32 #include <linux/highmem.h>
33 #include <linux/idr.h>
34 #include <linux/platform_data/x86/apple.h>
35 #include <linux/ptp_clock_kernel.h>
36 #include <linux/percpu.h>
37 
38 #define CREATE_TRACE_POINTS
39 #include <trace/events/spi.h>
40 EXPORT_TRACEPOINT_SYMBOL(spi_transfer_start);
41 EXPORT_TRACEPOINT_SYMBOL(spi_transfer_stop);
42 
43 #include "internals.h"
44 
45 static DEFINE_IDR(spi_master_idr);
46 
spidev_release(struct device * dev)47 static void spidev_release(struct device *dev)
48 {
49 	struct spi_device	*spi = to_spi_device(dev);
50 
51 	spi_controller_put(spi->controller);
52 	kfree(spi->driver_override);
53 	free_percpu(spi->pcpu_statistics);
54 	kfree(spi);
55 }
56 
57 static ssize_t
modalias_show(struct device * dev,struct device_attribute * a,char * buf)58 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
59 {
60 	const struct spi_device	*spi = to_spi_device(dev);
61 	int len;
62 
63 	len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
64 	if (len != -ENODEV)
65 		return len;
66 
67 	return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
68 }
69 static DEVICE_ATTR_RO(modalias);
70 
driver_override_store(struct device * dev,struct device_attribute * a,const char * buf,size_t count)71 static ssize_t driver_override_store(struct device *dev,
72 				     struct device_attribute *a,
73 				     const char *buf, size_t count)
74 {
75 	struct spi_device *spi = to_spi_device(dev);
76 	int ret;
77 
78 	ret = driver_set_override(dev, &spi->driver_override, buf, count);
79 	if (ret)
80 		return ret;
81 
82 	return count;
83 }
84 
driver_override_show(struct device * dev,struct device_attribute * a,char * buf)85 static ssize_t driver_override_show(struct device *dev,
86 				    struct device_attribute *a, char *buf)
87 {
88 	const struct spi_device *spi = to_spi_device(dev);
89 	ssize_t len;
90 
91 	device_lock(dev);
92 	len = snprintf(buf, PAGE_SIZE, "%s\n", spi->driver_override ? : "");
93 	device_unlock(dev);
94 	return len;
95 }
96 static DEVICE_ATTR_RW(driver_override);
97 
spi_alloc_pcpu_stats(struct device * dev)98 static struct spi_statistics __percpu *spi_alloc_pcpu_stats(struct device *dev)
99 {
100 	struct spi_statistics __percpu *pcpu_stats;
101 
102 	if (dev)
103 		pcpu_stats = devm_alloc_percpu(dev, struct spi_statistics);
104 	else
105 		pcpu_stats = alloc_percpu_gfp(struct spi_statistics, GFP_KERNEL);
106 
107 	if (pcpu_stats) {
108 		int cpu;
109 
110 		for_each_possible_cpu(cpu) {
111 			struct spi_statistics *stat;
112 
113 			stat = per_cpu_ptr(pcpu_stats, cpu);
114 			u64_stats_init(&stat->syncp);
115 		}
116 	}
117 	return pcpu_stats;
118 }
119 
120 #define spi_pcpu_stats_totalize(ret, in, field)				\
121 do {									\
122 	int i;								\
123 	ret = 0;							\
124 	for_each_possible_cpu(i) {					\
125 		const struct spi_statistics *pcpu_stats;		\
126 		u64 inc;						\
127 		unsigned int start;					\
128 		pcpu_stats = per_cpu_ptr(in, i);			\
129 		do {							\
130 			start = u64_stats_fetch_begin_irq(		\
131 					&pcpu_stats->syncp);		\
132 			inc = u64_stats_read(&pcpu_stats->field);	\
133 		} while (u64_stats_fetch_retry_irq(			\
134 					&pcpu_stats->syncp, start));	\
135 		ret += inc;						\
136 	}								\
137 } while (0)
138 
139 #define SPI_STATISTICS_ATTRS(field, file)				\
140 static ssize_t spi_controller_##field##_show(struct device *dev,	\
141 					     struct device_attribute *attr, \
142 					     char *buf)			\
143 {									\
144 	struct spi_controller *ctlr = container_of(dev,			\
145 					 struct spi_controller, dev);	\
146 	return spi_statistics_##field##_show(ctlr->pcpu_statistics, buf); \
147 }									\
148 static struct device_attribute dev_attr_spi_controller_##field = {	\
149 	.attr = { .name = file, .mode = 0444 },				\
150 	.show = spi_controller_##field##_show,				\
151 };									\
152 static ssize_t spi_device_##field##_show(struct device *dev,		\
153 					 struct device_attribute *attr,	\
154 					char *buf)			\
155 {									\
156 	struct spi_device *spi = to_spi_device(dev);			\
157 	return spi_statistics_##field##_show(spi->pcpu_statistics, buf); \
158 }									\
159 static struct device_attribute dev_attr_spi_device_##field = {		\
160 	.attr = { .name = file, .mode = 0444 },				\
161 	.show = spi_device_##field##_show,				\
162 }
163 
164 #define SPI_STATISTICS_SHOW_NAME(name, file, field)			\
165 static ssize_t spi_statistics_##name##_show(struct spi_statistics __percpu *stat, \
166 					    char *buf)			\
167 {									\
168 	ssize_t len;							\
169 	u64 val;							\
170 	spi_pcpu_stats_totalize(val, stat, field);			\
171 	len = sysfs_emit(buf, "%llu\n", val);				\
172 	return len;							\
173 }									\
174 SPI_STATISTICS_ATTRS(name, file)
175 
176 #define SPI_STATISTICS_SHOW(field)					\
177 	SPI_STATISTICS_SHOW_NAME(field, __stringify(field),		\
178 				 field)
179 
180 SPI_STATISTICS_SHOW(messages);
181 SPI_STATISTICS_SHOW(transfers);
182 SPI_STATISTICS_SHOW(errors);
183 SPI_STATISTICS_SHOW(timedout);
184 
185 SPI_STATISTICS_SHOW(spi_sync);
186 SPI_STATISTICS_SHOW(spi_sync_immediate);
187 SPI_STATISTICS_SHOW(spi_async);
188 
189 SPI_STATISTICS_SHOW(bytes);
190 SPI_STATISTICS_SHOW(bytes_rx);
191 SPI_STATISTICS_SHOW(bytes_tx);
192 
193 #define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number)		\
194 	SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index,		\
195 				 "transfer_bytes_histo_" number,	\
196 				 transfer_bytes_histo[index])
197 SPI_STATISTICS_TRANSFER_BYTES_HISTO(0,  "0-1");
198 SPI_STATISTICS_TRANSFER_BYTES_HISTO(1,  "2-3");
199 SPI_STATISTICS_TRANSFER_BYTES_HISTO(2,  "4-7");
200 SPI_STATISTICS_TRANSFER_BYTES_HISTO(3,  "8-15");
201 SPI_STATISTICS_TRANSFER_BYTES_HISTO(4,  "16-31");
202 SPI_STATISTICS_TRANSFER_BYTES_HISTO(5,  "32-63");
203 SPI_STATISTICS_TRANSFER_BYTES_HISTO(6,  "64-127");
204 SPI_STATISTICS_TRANSFER_BYTES_HISTO(7,  "128-255");
205 SPI_STATISTICS_TRANSFER_BYTES_HISTO(8,  "256-511");
206 SPI_STATISTICS_TRANSFER_BYTES_HISTO(9,  "512-1023");
207 SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
208 SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
209 SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
210 SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
211 SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
212 SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
213 SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
214 
215 SPI_STATISTICS_SHOW(transfers_split_maxsize);
216 
217 static struct attribute *spi_dev_attrs[] = {
218 	&dev_attr_modalias.attr,
219 	&dev_attr_driver_override.attr,
220 	NULL,
221 };
222 
223 static const struct attribute_group spi_dev_group = {
224 	.attrs  = spi_dev_attrs,
225 };
226 
227 static struct attribute *spi_device_statistics_attrs[] = {
228 	&dev_attr_spi_device_messages.attr,
229 	&dev_attr_spi_device_transfers.attr,
230 	&dev_attr_spi_device_errors.attr,
231 	&dev_attr_spi_device_timedout.attr,
232 	&dev_attr_spi_device_spi_sync.attr,
233 	&dev_attr_spi_device_spi_sync_immediate.attr,
234 	&dev_attr_spi_device_spi_async.attr,
235 	&dev_attr_spi_device_bytes.attr,
236 	&dev_attr_spi_device_bytes_rx.attr,
237 	&dev_attr_spi_device_bytes_tx.attr,
238 	&dev_attr_spi_device_transfer_bytes_histo0.attr,
239 	&dev_attr_spi_device_transfer_bytes_histo1.attr,
240 	&dev_attr_spi_device_transfer_bytes_histo2.attr,
241 	&dev_attr_spi_device_transfer_bytes_histo3.attr,
242 	&dev_attr_spi_device_transfer_bytes_histo4.attr,
243 	&dev_attr_spi_device_transfer_bytes_histo5.attr,
244 	&dev_attr_spi_device_transfer_bytes_histo6.attr,
245 	&dev_attr_spi_device_transfer_bytes_histo7.attr,
246 	&dev_attr_spi_device_transfer_bytes_histo8.attr,
247 	&dev_attr_spi_device_transfer_bytes_histo9.attr,
248 	&dev_attr_spi_device_transfer_bytes_histo10.attr,
249 	&dev_attr_spi_device_transfer_bytes_histo11.attr,
250 	&dev_attr_spi_device_transfer_bytes_histo12.attr,
251 	&dev_attr_spi_device_transfer_bytes_histo13.attr,
252 	&dev_attr_spi_device_transfer_bytes_histo14.attr,
253 	&dev_attr_spi_device_transfer_bytes_histo15.attr,
254 	&dev_attr_spi_device_transfer_bytes_histo16.attr,
255 	&dev_attr_spi_device_transfers_split_maxsize.attr,
256 	NULL,
257 };
258 
259 static const struct attribute_group spi_device_statistics_group = {
260 	.name  = "statistics",
261 	.attrs  = spi_device_statistics_attrs,
262 };
263 
264 static const struct attribute_group *spi_dev_groups[] = {
265 	&spi_dev_group,
266 	&spi_device_statistics_group,
267 	NULL,
268 };
269 
270 static struct attribute *spi_controller_statistics_attrs[] = {
271 	&dev_attr_spi_controller_messages.attr,
272 	&dev_attr_spi_controller_transfers.attr,
273 	&dev_attr_spi_controller_errors.attr,
274 	&dev_attr_spi_controller_timedout.attr,
275 	&dev_attr_spi_controller_spi_sync.attr,
276 	&dev_attr_spi_controller_spi_sync_immediate.attr,
277 	&dev_attr_spi_controller_spi_async.attr,
278 	&dev_attr_spi_controller_bytes.attr,
279 	&dev_attr_spi_controller_bytes_rx.attr,
280 	&dev_attr_spi_controller_bytes_tx.attr,
281 	&dev_attr_spi_controller_transfer_bytes_histo0.attr,
282 	&dev_attr_spi_controller_transfer_bytes_histo1.attr,
283 	&dev_attr_spi_controller_transfer_bytes_histo2.attr,
284 	&dev_attr_spi_controller_transfer_bytes_histo3.attr,
285 	&dev_attr_spi_controller_transfer_bytes_histo4.attr,
286 	&dev_attr_spi_controller_transfer_bytes_histo5.attr,
287 	&dev_attr_spi_controller_transfer_bytes_histo6.attr,
288 	&dev_attr_spi_controller_transfer_bytes_histo7.attr,
289 	&dev_attr_spi_controller_transfer_bytes_histo8.attr,
290 	&dev_attr_spi_controller_transfer_bytes_histo9.attr,
291 	&dev_attr_spi_controller_transfer_bytes_histo10.attr,
292 	&dev_attr_spi_controller_transfer_bytes_histo11.attr,
293 	&dev_attr_spi_controller_transfer_bytes_histo12.attr,
294 	&dev_attr_spi_controller_transfer_bytes_histo13.attr,
295 	&dev_attr_spi_controller_transfer_bytes_histo14.attr,
296 	&dev_attr_spi_controller_transfer_bytes_histo15.attr,
297 	&dev_attr_spi_controller_transfer_bytes_histo16.attr,
298 	&dev_attr_spi_controller_transfers_split_maxsize.attr,
299 	NULL,
300 };
301 
302 static const struct attribute_group spi_controller_statistics_group = {
303 	.name  = "statistics",
304 	.attrs  = spi_controller_statistics_attrs,
305 };
306 
307 static const struct attribute_group *spi_master_groups[] = {
308 	&spi_controller_statistics_group,
309 	NULL,
310 };
311 
spi_statistics_add_transfer_stats(struct spi_statistics __percpu * pcpu_stats,struct spi_transfer * xfer,struct spi_controller * ctlr)312 static void spi_statistics_add_transfer_stats(struct spi_statistics __percpu *pcpu_stats,
313 					      struct spi_transfer *xfer,
314 					      struct spi_controller *ctlr)
315 {
316 	int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
317 	struct spi_statistics *stats;
318 
319 	if (l2len < 0)
320 		l2len = 0;
321 
322 	get_cpu();
323 	stats = this_cpu_ptr(pcpu_stats);
324 	u64_stats_update_begin(&stats->syncp);
325 
326 	u64_stats_inc(&stats->transfers);
327 	u64_stats_inc(&stats->transfer_bytes_histo[l2len]);
328 
329 	u64_stats_add(&stats->bytes, xfer->len);
330 	if ((xfer->tx_buf) &&
331 	    (xfer->tx_buf != ctlr->dummy_tx))
332 		u64_stats_add(&stats->bytes_tx, xfer->len);
333 	if ((xfer->rx_buf) &&
334 	    (xfer->rx_buf != ctlr->dummy_rx))
335 		u64_stats_add(&stats->bytes_rx, xfer->len);
336 
337 	u64_stats_update_end(&stats->syncp);
338 	put_cpu();
339 }
340 
341 /*
342  * modalias support makes "modprobe $MODALIAS" new-style hotplug work,
343  * and the sysfs version makes coldplug work too.
344  */
spi_match_id(const struct spi_device_id * id,const char * name)345 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id, const char *name)
346 {
347 	while (id->name[0]) {
348 		if (!strcmp(name, id->name))
349 			return id;
350 		id++;
351 	}
352 	return NULL;
353 }
354 
spi_get_device_id(const struct spi_device * sdev)355 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
356 {
357 	const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
358 
359 	return spi_match_id(sdrv->id_table, sdev->modalias);
360 }
361 EXPORT_SYMBOL_GPL(spi_get_device_id);
362 
spi_match_device(struct device * dev,struct device_driver * drv)363 static int spi_match_device(struct device *dev, struct device_driver *drv)
364 {
365 	const struct spi_device	*spi = to_spi_device(dev);
366 	const struct spi_driver	*sdrv = to_spi_driver(drv);
367 
368 	/* Check override first, and if set, only use the named driver */
369 	if (spi->driver_override)
370 		return strcmp(spi->driver_override, drv->name) == 0;
371 
372 	/* Attempt an OF style match */
373 	if (of_driver_match_device(dev, drv))
374 		return 1;
375 
376 	/* Then try ACPI */
377 	if (acpi_driver_match_device(dev, drv))
378 		return 1;
379 
380 	if (sdrv->id_table)
381 		return !!spi_match_id(sdrv->id_table, spi->modalias);
382 
383 	return strcmp(spi->modalias, drv->name) == 0;
384 }
385 
spi_uevent(struct device * dev,struct kobj_uevent_env * env)386 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
387 {
388 	const struct spi_device		*spi = to_spi_device(dev);
389 	int rc;
390 
391 	rc = acpi_device_uevent_modalias(dev, env);
392 	if (rc != -ENODEV)
393 		return rc;
394 
395 	return add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
396 }
397 
spi_probe(struct device * dev)398 static int spi_probe(struct device *dev)
399 {
400 	const struct spi_driver		*sdrv = to_spi_driver(dev->driver);
401 	struct spi_device		*spi = to_spi_device(dev);
402 	int ret;
403 
404 	ret = of_clk_set_defaults(dev->of_node, false);
405 	if (ret)
406 		return ret;
407 
408 	if (dev->of_node) {
409 		spi->irq = of_irq_get(dev->of_node, 0);
410 		if (spi->irq == -EPROBE_DEFER)
411 			return -EPROBE_DEFER;
412 		if (spi->irq < 0)
413 			spi->irq = 0;
414 	}
415 
416 	ret = dev_pm_domain_attach(dev, true);
417 	if (ret)
418 		return ret;
419 
420 	if (sdrv->probe) {
421 		ret = sdrv->probe(spi);
422 		if (ret)
423 			dev_pm_domain_detach(dev, true);
424 	}
425 
426 	return ret;
427 }
428 
spi_remove(struct device * dev)429 static void spi_remove(struct device *dev)
430 {
431 	const struct spi_driver		*sdrv = to_spi_driver(dev->driver);
432 
433 	if (sdrv->remove)
434 		sdrv->remove(to_spi_device(dev));
435 
436 	dev_pm_domain_detach(dev, true);
437 }
438 
spi_shutdown(struct device * dev)439 static void spi_shutdown(struct device *dev)
440 {
441 	if (dev->driver) {
442 		const struct spi_driver	*sdrv = to_spi_driver(dev->driver);
443 
444 		if (sdrv->shutdown)
445 			sdrv->shutdown(to_spi_device(dev));
446 	}
447 }
448 
449 struct bus_type spi_bus_type = {
450 	.name		= "spi",
451 	.dev_groups	= spi_dev_groups,
452 	.match		= spi_match_device,
453 	.uevent		= spi_uevent,
454 	.probe		= spi_probe,
455 	.remove		= spi_remove,
456 	.shutdown	= spi_shutdown,
457 };
458 EXPORT_SYMBOL_GPL(spi_bus_type);
459 
460 /**
461  * __spi_register_driver - register a SPI driver
462  * @owner: owner module of the driver to register
463  * @sdrv: the driver to register
464  * Context: can sleep
465  *
466  * Return: zero on success, else a negative error code.
467  */
__spi_register_driver(struct module * owner,struct spi_driver * sdrv)468 int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
469 {
470 	sdrv->driver.owner = owner;
471 	sdrv->driver.bus = &spi_bus_type;
472 
473 	/*
474 	 * For Really Good Reasons we use spi: modaliases not of:
475 	 * modaliases for DT so module autoloading won't work if we
476 	 * don't have a spi_device_id as well as a compatible string.
477 	 */
478 	if (sdrv->driver.of_match_table) {
479 		const struct of_device_id *of_id;
480 
481 		for (of_id = sdrv->driver.of_match_table; of_id->compatible[0];
482 		     of_id++) {
483 			const char *of_name;
484 
485 			/* Strip off any vendor prefix */
486 			of_name = strnchr(of_id->compatible,
487 					  sizeof(of_id->compatible), ',');
488 			if (of_name)
489 				of_name++;
490 			else
491 				of_name = of_id->compatible;
492 
493 			if (sdrv->id_table) {
494 				const struct spi_device_id *spi_id;
495 
496 				spi_id = spi_match_id(sdrv->id_table, of_name);
497 				if (spi_id)
498 					continue;
499 			} else {
500 				if (strcmp(sdrv->driver.name, of_name) == 0)
501 					continue;
502 			}
503 
504 			pr_warn("SPI driver %s has no spi_device_id for %s\n",
505 				sdrv->driver.name, of_id->compatible);
506 		}
507 	}
508 
509 	return driver_register(&sdrv->driver);
510 }
511 EXPORT_SYMBOL_GPL(__spi_register_driver);
512 
513 /*-------------------------------------------------------------------------*/
514 
515 /*
516  * SPI devices should normally not be created by SPI device drivers; that
517  * would make them board-specific.  Similarly with SPI controller drivers.
518  * Device registration normally goes into like arch/.../mach.../board-YYY.c
519  * with other readonly (flashable) information about mainboard devices.
520  */
521 
522 struct boardinfo {
523 	struct list_head	list;
524 	struct spi_board_info	board_info;
525 };
526 
527 static LIST_HEAD(board_list);
528 static LIST_HEAD(spi_controller_list);
529 
530 /*
531  * Used to protect add/del operation for board_info list and
532  * spi_controller list, and their matching process also used
533  * to protect object of type struct idr.
534  */
535 static DEFINE_MUTEX(board_lock);
536 
537 /**
538  * spi_alloc_device - Allocate a new SPI device
539  * @ctlr: Controller to which device is connected
540  * Context: can sleep
541  *
542  * Allows a driver to allocate and initialize a spi_device without
543  * registering it immediately.  This allows a driver to directly
544  * fill the spi_device with device parameters before calling
545  * spi_add_device() on it.
546  *
547  * Caller is responsible to call spi_add_device() on the returned
548  * spi_device structure to add it to the SPI controller.  If the caller
549  * needs to discard the spi_device without adding it, then it should
550  * call spi_dev_put() on it.
551  *
552  * Return: a pointer to the new device, or NULL.
553  */
spi_alloc_device(struct spi_controller * ctlr)554 struct spi_device *spi_alloc_device(struct spi_controller *ctlr)
555 {
556 	struct spi_device	*spi;
557 
558 	if (!spi_controller_get(ctlr))
559 		return NULL;
560 
561 	spi = kzalloc(sizeof(*spi), GFP_KERNEL);
562 	if (!spi) {
563 		spi_controller_put(ctlr);
564 		return NULL;
565 	}
566 
567 	spi->pcpu_statistics = spi_alloc_pcpu_stats(NULL);
568 	if (!spi->pcpu_statistics) {
569 		kfree(spi);
570 		spi_controller_put(ctlr);
571 		return NULL;
572 	}
573 
574 	spi->master = spi->controller = ctlr;
575 	spi->dev.parent = &ctlr->dev;
576 	spi->dev.bus = &spi_bus_type;
577 	spi->dev.release = spidev_release;
578 	spi->mode = ctlr->buswidth_override_bits;
579 
580 	device_initialize(&spi->dev);
581 	return spi;
582 }
583 EXPORT_SYMBOL_GPL(spi_alloc_device);
584 
spi_dev_set_name(struct spi_device * spi)585 static void spi_dev_set_name(struct spi_device *spi)
586 {
587 	struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
588 
589 	if (adev) {
590 		dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
591 		return;
592 	}
593 
594 	dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->controller->dev),
595 		     spi->chip_select);
596 }
597 
spi_dev_check(struct device * dev,void * data)598 static int spi_dev_check(struct device *dev, void *data)
599 {
600 	struct spi_device *spi = to_spi_device(dev);
601 	struct spi_device *new_spi = data;
602 
603 	if (spi->controller == new_spi->controller &&
604 	    spi->chip_select == new_spi->chip_select)
605 		return -EBUSY;
606 	return 0;
607 }
608 
spi_cleanup(struct spi_device * spi)609 static void spi_cleanup(struct spi_device *spi)
610 {
611 	if (spi->controller->cleanup)
612 		spi->controller->cleanup(spi);
613 }
614 
__spi_add_device(struct spi_device * spi)615 static int __spi_add_device(struct spi_device *spi)
616 {
617 	struct spi_controller *ctlr = spi->controller;
618 	struct device *dev = ctlr->dev.parent;
619 	int status;
620 
621 	/*
622 	 * We need to make sure there's no other device with this
623 	 * chipselect **BEFORE** we call setup(), else we'll trash
624 	 * its configuration.
625 	 */
626 	status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
627 	if (status) {
628 		dev_err(dev, "chipselect %d already in use\n",
629 				spi->chip_select);
630 		return status;
631 	}
632 
633 	/* Controller may unregister concurrently */
634 	if (IS_ENABLED(CONFIG_SPI_DYNAMIC) &&
635 	    !device_is_registered(&ctlr->dev)) {
636 		return -ENODEV;
637 	}
638 
639 	if (ctlr->cs_gpiods)
640 		spi->cs_gpiod = ctlr->cs_gpiods[spi->chip_select];
641 
642 	/*
643 	 * Drivers may modify this initial i/o setup, but will
644 	 * normally rely on the device being setup.  Devices
645 	 * using SPI_CS_HIGH can't coexist well otherwise...
646 	 */
647 	status = spi_setup(spi);
648 	if (status < 0) {
649 		dev_err(dev, "can't setup %s, status %d\n",
650 				dev_name(&spi->dev), status);
651 		return status;
652 	}
653 
654 	/* Device may be bound to an active driver when this returns */
655 	status = device_add(&spi->dev);
656 	if (status < 0) {
657 		dev_err(dev, "can't add %s, status %d\n",
658 				dev_name(&spi->dev), status);
659 		spi_cleanup(spi);
660 	} else {
661 		dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
662 	}
663 
664 	return status;
665 }
666 
667 /**
668  * spi_add_device - Add spi_device allocated with spi_alloc_device
669  * @spi: spi_device to register
670  *
671  * Companion function to spi_alloc_device.  Devices allocated with
672  * spi_alloc_device can be added onto the spi bus with this function.
673  *
674  * Return: 0 on success; negative errno on failure
675  */
spi_add_device(struct spi_device * spi)676 int spi_add_device(struct spi_device *spi)
677 {
678 	struct spi_controller *ctlr = spi->controller;
679 	struct device *dev = ctlr->dev.parent;
680 	int status;
681 
682 	/* Chipselects are numbered 0..max; validate. */
683 	if (spi->chip_select >= ctlr->num_chipselect) {
684 		dev_err(dev, "cs%d >= max %d\n", spi->chip_select,
685 			ctlr->num_chipselect);
686 		return -EINVAL;
687 	}
688 
689 	/* Set the bus ID string */
690 	spi_dev_set_name(spi);
691 
692 	mutex_lock(&ctlr->add_lock);
693 	status = __spi_add_device(spi);
694 	mutex_unlock(&ctlr->add_lock);
695 	return status;
696 }
697 EXPORT_SYMBOL_GPL(spi_add_device);
698 
spi_add_device_locked(struct spi_device * spi)699 static int spi_add_device_locked(struct spi_device *spi)
700 {
701 	struct spi_controller *ctlr = spi->controller;
702 	struct device *dev = ctlr->dev.parent;
703 
704 	/* Chipselects are numbered 0..max; validate. */
705 	if (spi->chip_select >= ctlr->num_chipselect) {
706 		dev_err(dev, "cs%d >= max %d\n", spi->chip_select,
707 			ctlr->num_chipselect);
708 		return -EINVAL;
709 	}
710 
711 	/* Set the bus ID string */
712 	spi_dev_set_name(spi);
713 
714 	WARN_ON(!mutex_is_locked(&ctlr->add_lock));
715 	return __spi_add_device(spi);
716 }
717 
718 /**
719  * spi_new_device - instantiate one new SPI device
720  * @ctlr: Controller to which device is connected
721  * @chip: Describes the SPI device
722  * Context: can sleep
723  *
724  * On typical mainboards, this is purely internal; and it's not needed
725  * after board init creates the hard-wired devices.  Some development
726  * platforms may not be able to use spi_register_board_info though, and
727  * this is exported so that for example a USB or parport based adapter
728  * driver could add devices (which it would learn about out-of-band).
729  *
730  * Return: the new device, or NULL.
731  */
spi_new_device(struct spi_controller * ctlr,struct spi_board_info * chip)732 struct spi_device *spi_new_device(struct spi_controller *ctlr,
733 				  struct spi_board_info *chip)
734 {
735 	struct spi_device	*proxy;
736 	int			status;
737 
738 	/*
739 	 * NOTE:  caller did any chip->bus_num checks necessary.
740 	 *
741 	 * Also, unless we change the return value convention to use
742 	 * error-or-pointer (not NULL-or-pointer), troubleshootability
743 	 * suggests syslogged diagnostics are best here (ugh).
744 	 */
745 
746 	proxy = spi_alloc_device(ctlr);
747 	if (!proxy)
748 		return NULL;
749 
750 	WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
751 
752 	proxy->chip_select = chip->chip_select;
753 	proxy->max_speed_hz = chip->max_speed_hz;
754 	proxy->mode = chip->mode;
755 	proxy->irq = chip->irq;
756 	strscpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
757 	proxy->dev.platform_data = (void *) chip->platform_data;
758 	proxy->controller_data = chip->controller_data;
759 	proxy->controller_state = NULL;
760 
761 	if (chip->swnode) {
762 		status = device_add_software_node(&proxy->dev, chip->swnode);
763 		if (status) {
764 			dev_err(&ctlr->dev, "failed to add software node to '%s': %d\n",
765 				chip->modalias, status);
766 			goto err_dev_put;
767 		}
768 	}
769 
770 	status = spi_add_device(proxy);
771 	if (status < 0)
772 		goto err_dev_put;
773 
774 	return proxy;
775 
776 err_dev_put:
777 	device_remove_software_node(&proxy->dev);
778 	spi_dev_put(proxy);
779 	return NULL;
780 }
781 EXPORT_SYMBOL_GPL(spi_new_device);
782 
783 /**
784  * spi_unregister_device - unregister a single SPI device
785  * @spi: spi_device to unregister
786  *
787  * Start making the passed SPI device vanish. Normally this would be handled
788  * by spi_unregister_controller().
789  */
spi_unregister_device(struct spi_device * spi)790 void spi_unregister_device(struct spi_device *spi)
791 {
792 	if (!spi)
793 		return;
794 
795 	if (spi->dev.of_node) {
796 		of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
797 		of_node_put(spi->dev.of_node);
798 	}
799 	if (ACPI_COMPANION(&spi->dev))
800 		acpi_device_clear_enumerated(ACPI_COMPANION(&spi->dev));
801 	device_remove_software_node(&spi->dev);
802 	device_del(&spi->dev);
803 	spi_cleanup(spi);
804 	put_device(&spi->dev);
805 }
806 EXPORT_SYMBOL_GPL(spi_unregister_device);
807 
spi_match_controller_to_boardinfo(struct spi_controller * ctlr,struct spi_board_info * bi)808 static void spi_match_controller_to_boardinfo(struct spi_controller *ctlr,
809 					      struct spi_board_info *bi)
810 {
811 	struct spi_device *dev;
812 
813 	if (ctlr->bus_num != bi->bus_num)
814 		return;
815 
816 	dev = spi_new_device(ctlr, bi);
817 	if (!dev)
818 		dev_err(ctlr->dev.parent, "can't create new device for %s\n",
819 			bi->modalias);
820 }
821 
822 /**
823  * spi_register_board_info - register SPI devices for a given board
824  * @info: array of chip descriptors
825  * @n: how many descriptors are provided
826  * Context: can sleep
827  *
828  * Board-specific early init code calls this (probably during arch_initcall)
829  * with segments of the SPI device table.  Any device nodes are created later,
830  * after the relevant parent SPI controller (bus_num) is defined.  We keep
831  * this table of devices forever, so that reloading a controller driver will
832  * not make Linux forget about these hard-wired devices.
833  *
834  * Other code can also call this, e.g. a particular add-on board might provide
835  * SPI devices through its expansion connector, so code initializing that board
836  * would naturally declare its SPI devices.
837  *
838  * The board info passed can safely be __initdata ... but be careful of
839  * any embedded pointers (platform_data, etc), they're copied as-is.
840  *
841  * Return: zero on success, else a negative error code.
842  */
spi_register_board_info(struct spi_board_info const * info,unsigned n)843 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
844 {
845 	struct boardinfo *bi;
846 	int i;
847 
848 	if (!n)
849 		return 0;
850 
851 	bi = kcalloc(n, sizeof(*bi), GFP_KERNEL);
852 	if (!bi)
853 		return -ENOMEM;
854 
855 	for (i = 0; i < n; i++, bi++, info++) {
856 		struct spi_controller *ctlr;
857 
858 		memcpy(&bi->board_info, info, sizeof(*info));
859 
860 		mutex_lock(&board_lock);
861 		list_add_tail(&bi->list, &board_list);
862 		list_for_each_entry(ctlr, &spi_controller_list, list)
863 			spi_match_controller_to_boardinfo(ctlr,
864 							  &bi->board_info);
865 		mutex_unlock(&board_lock);
866 	}
867 
868 	return 0;
869 }
870 
871 /*-------------------------------------------------------------------------*/
872 
873 /* Core methods for SPI resource management */
874 
875 /**
876  * spi_res_alloc - allocate a spi resource that is life-cycle managed
877  *                 during the processing of a spi_message while using
878  *                 spi_transfer_one
879  * @spi:     the spi device for which we allocate memory
880  * @release: the release code to execute for this resource
881  * @size:    size to alloc and return
882  * @gfp:     GFP allocation flags
883  *
884  * Return: the pointer to the allocated data
885  *
886  * This may get enhanced in the future to allocate from a memory pool
887  * of the @spi_device or @spi_controller to avoid repeated allocations.
888  */
spi_res_alloc(struct spi_device * spi,spi_res_release_t release,size_t size,gfp_t gfp)889 static void *spi_res_alloc(struct spi_device *spi, spi_res_release_t release,
890 			   size_t size, gfp_t gfp)
891 {
892 	struct spi_res *sres;
893 
894 	sres = kzalloc(sizeof(*sres) + size, gfp);
895 	if (!sres)
896 		return NULL;
897 
898 	INIT_LIST_HEAD(&sres->entry);
899 	sres->release = release;
900 
901 	return sres->data;
902 }
903 
904 /**
905  * spi_res_free - free an spi resource
906  * @res: pointer to the custom data of a resource
907  */
spi_res_free(void * res)908 static void spi_res_free(void *res)
909 {
910 	struct spi_res *sres = container_of(res, struct spi_res, data);
911 
912 	if (!res)
913 		return;
914 
915 	WARN_ON(!list_empty(&sres->entry));
916 	kfree(sres);
917 }
918 
919 /**
920  * spi_res_add - add a spi_res to the spi_message
921  * @message: the spi message
922  * @res:     the spi_resource
923  */
spi_res_add(struct spi_message * message,void * res)924 static void spi_res_add(struct spi_message *message, void *res)
925 {
926 	struct spi_res *sres = container_of(res, struct spi_res, data);
927 
928 	WARN_ON(!list_empty(&sres->entry));
929 	list_add_tail(&sres->entry, &message->resources);
930 }
931 
932 /**
933  * spi_res_release - release all spi resources for this message
934  * @ctlr:  the @spi_controller
935  * @message: the @spi_message
936  */
spi_res_release(struct spi_controller * ctlr,struct spi_message * message)937 static void spi_res_release(struct spi_controller *ctlr, struct spi_message *message)
938 {
939 	struct spi_res *res, *tmp;
940 
941 	list_for_each_entry_safe_reverse(res, tmp, &message->resources, entry) {
942 		if (res->release)
943 			res->release(ctlr, message, res->data);
944 
945 		list_del(&res->entry);
946 
947 		kfree(res);
948 	}
949 }
950 
951 /*-------------------------------------------------------------------------*/
952 
spi_set_cs(struct spi_device * spi,bool enable,bool force)953 static void spi_set_cs(struct spi_device *spi, bool enable, bool force)
954 {
955 	bool activate = enable;
956 
957 	/*
958 	 * Avoid calling into the driver (or doing delays) if the chip select
959 	 * isn't actually changing from the last time this was called.
960 	 */
961 	if (!force && ((enable && spi->controller->last_cs == spi->chip_select) ||
962 				(!enable && spi->controller->last_cs != spi->chip_select)) &&
963 	    (spi->controller->last_cs_mode_high == (spi->mode & SPI_CS_HIGH)))
964 		return;
965 
966 	trace_spi_set_cs(spi, activate);
967 
968 	spi->controller->last_cs = enable ? spi->chip_select : -1;
969 	spi->controller->last_cs_mode_high = spi->mode & SPI_CS_HIGH;
970 
971 	if ((spi->cs_gpiod || !spi->controller->set_cs_timing) && !activate) {
972 		spi_delay_exec(&spi->cs_hold, NULL);
973 	}
974 
975 	if (spi->mode & SPI_CS_HIGH)
976 		enable = !enable;
977 
978 	if (spi->cs_gpiod) {
979 		if (!(spi->mode & SPI_NO_CS)) {
980 			/*
981 			 * Historically ACPI has no means of the GPIO polarity and
982 			 * thus the SPISerialBus() resource defines it on the per-chip
983 			 * basis. In order to avoid a chain of negations, the GPIO
984 			 * polarity is considered being Active High. Even for the cases
985 			 * when _DSD() is involved (in the updated versions of ACPI)
986 			 * the GPIO CS polarity must be defined Active High to avoid
987 			 * ambiguity. That's why we use enable, that takes SPI_CS_HIGH
988 			 * into account.
989 			 */
990 			if (has_acpi_companion(&spi->dev))
991 				gpiod_set_value_cansleep(spi->cs_gpiod, !enable);
992 			else
993 				/* Polarity handled by GPIO library */
994 				gpiod_set_value_cansleep(spi->cs_gpiod, activate);
995 		}
996 		/* Some SPI masters need both GPIO CS & slave_select */
997 		if ((spi->controller->flags & SPI_MASTER_GPIO_SS) &&
998 		    spi->controller->set_cs)
999 			spi->controller->set_cs(spi, !enable);
1000 	} else if (spi->controller->set_cs) {
1001 		spi->controller->set_cs(spi, !enable);
1002 	}
1003 
1004 	if (spi->cs_gpiod || !spi->controller->set_cs_timing) {
1005 		if (activate)
1006 			spi_delay_exec(&spi->cs_setup, NULL);
1007 		else
1008 			spi_delay_exec(&spi->cs_inactive, NULL);
1009 	}
1010 }
1011 
1012 #ifdef CONFIG_HAS_DMA
spi_map_buf_attrs(struct spi_controller * ctlr,struct device * dev,struct sg_table * sgt,void * buf,size_t len,enum dma_data_direction dir,unsigned long attrs)1013 static int spi_map_buf_attrs(struct spi_controller *ctlr, struct device *dev,
1014 			     struct sg_table *sgt, void *buf, size_t len,
1015 			     enum dma_data_direction dir, unsigned long attrs)
1016 {
1017 	const bool vmalloced_buf = is_vmalloc_addr(buf);
1018 	unsigned int max_seg_size = dma_get_max_seg_size(dev);
1019 #ifdef CONFIG_HIGHMEM
1020 	const bool kmap_buf = ((unsigned long)buf >= PKMAP_BASE &&
1021 				(unsigned long)buf < (PKMAP_BASE +
1022 					(LAST_PKMAP * PAGE_SIZE)));
1023 #else
1024 	const bool kmap_buf = false;
1025 #endif
1026 	int desc_len;
1027 	int sgs;
1028 	struct page *vm_page;
1029 	struct scatterlist *sg;
1030 	void *sg_buf;
1031 	size_t min;
1032 	int i, ret;
1033 
1034 	if (vmalloced_buf || kmap_buf) {
1035 		desc_len = min_t(unsigned long, max_seg_size, PAGE_SIZE);
1036 		sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
1037 	} else if (virt_addr_valid(buf)) {
1038 		desc_len = min_t(size_t, max_seg_size, ctlr->max_dma_len);
1039 		sgs = DIV_ROUND_UP(len, desc_len);
1040 	} else {
1041 		return -EINVAL;
1042 	}
1043 
1044 	ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
1045 	if (ret != 0)
1046 		return ret;
1047 
1048 	sg = &sgt->sgl[0];
1049 	for (i = 0; i < sgs; i++) {
1050 
1051 		if (vmalloced_buf || kmap_buf) {
1052 			/*
1053 			 * Next scatterlist entry size is the minimum between
1054 			 * the desc_len and the remaining buffer length that
1055 			 * fits in a page.
1056 			 */
1057 			min = min_t(size_t, desc_len,
1058 				    min_t(size_t, len,
1059 					  PAGE_SIZE - offset_in_page(buf)));
1060 			if (vmalloced_buf)
1061 				vm_page = vmalloc_to_page(buf);
1062 			else
1063 				vm_page = kmap_to_page(buf);
1064 			if (!vm_page) {
1065 				sg_free_table(sgt);
1066 				return -ENOMEM;
1067 			}
1068 			sg_set_page(sg, vm_page,
1069 				    min, offset_in_page(buf));
1070 		} else {
1071 			min = min_t(size_t, len, desc_len);
1072 			sg_buf = buf;
1073 			sg_set_buf(sg, sg_buf, min);
1074 		}
1075 
1076 		buf += min;
1077 		len -= min;
1078 		sg = sg_next(sg);
1079 	}
1080 
1081 	ret = dma_map_sgtable(dev, sgt, dir, attrs);
1082 	if (ret < 0) {
1083 		sg_free_table(sgt);
1084 		return ret;
1085 	}
1086 
1087 	return 0;
1088 }
1089 
spi_map_buf(struct spi_controller * ctlr,struct device * dev,struct sg_table * sgt,void * buf,size_t len,enum dma_data_direction dir)1090 int spi_map_buf(struct spi_controller *ctlr, struct device *dev,
1091 		struct sg_table *sgt, void *buf, size_t len,
1092 		enum dma_data_direction dir)
1093 {
1094 	return spi_map_buf_attrs(ctlr, dev, sgt, buf, len, dir, 0);
1095 }
1096 
spi_unmap_buf_attrs(struct spi_controller * ctlr,struct device * dev,struct sg_table * sgt,enum dma_data_direction dir,unsigned long attrs)1097 static void spi_unmap_buf_attrs(struct spi_controller *ctlr,
1098 				struct device *dev, struct sg_table *sgt,
1099 				enum dma_data_direction dir,
1100 				unsigned long attrs)
1101 {
1102 	if (sgt->orig_nents) {
1103 		dma_unmap_sgtable(dev, sgt, dir, attrs);
1104 		sg_free_table(sgt);
1105 		sgt->orig_nents = 0;
1106 		sgt->nents = 0;
1107 	}
1108 }
1109 
spi_unmap_buf(struct spi_controller * ctlr,struct device * dev,struct sg_table * sgt,enum dma_data_direction dir)1110 void spi_unmap_buf(struct spi_controller *ctlr, struct device *dev,
1111 		   struct sg_table *sgt, enum dma_data_direction dir)
1112 {
1113 	spi_unmap_buf_attrs(ctlr, dev, sgt, dir, 0);
1114 }
1115 
__spi_map_msg(struct spi_controller * ctlr,struct spi_message * msg)1116 static int __spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
1117 {
1118 	struct device *tx_dev, *rx_dev;
1119 	struct spi_transfer *xfer;
1120 	int ret;
1121 
1122 	if (!ctlr->can_dma)
1123 		return 0;
1124 
1125 	if (ctlr->dma_tx)
1126 		tx_dev = ctlr->dma_tx->device->dev;
1127 	else if (ctlr->dma_map_dev)
1128 		tx_dev = ctlr->dma_map_dev;
1129 	else
1130 		tx_dev = ctlr->dev.parent;
1131 
1132 	if (ctlr->dma_rx)
1133 		rx_dev = ctlr->dma_rx->device->dev;
1134 	else if (ctlr->dma_map_dev)
1135 		rx_dev = ctlr->dma_map_dev;
1136 	else
1137 		rx_dev = ctlr->dev.parent;
1138 
1139 	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1140 		/* The sync is done before each transfer. */
1141 		unsigned long attrs = DMA_ATTR_SKIP_CPU_SYNC;
1142 
1143 		if (!ctlr->can_dma(ctlr, msg->spi, xfer))
1144 			continue;
1145 
1146 		if (xfer->tx_buf != NULL) {
1147 			ret = spi_map_buf_attrs(ctlr, tx_dev, &xfer->tx_sg,
1148 						(void *)xfer->tx_buf,
1149 						xfer->len, DMA_TO_DEVICE,
1150 						attrs);
1151 			if (ret != 0)
1152 				return ret;
1153 		}
1154 
1155 		if (xfer->rx_buf != NULL) {
1156 			ret = spi_map_buf_attrs(ctlr, rx_dev, &xfer->rx_sg,
1157 						xfer->rx_buf, xfer->len,
1158 						DMA_FROM_DEVICE, attrs);
1159 			if (ret != 0) {
1160 				spi_unmap_buf_attrs(ctlr, tx_dev,
1161 						&xfer->tx_sg, DMA_TO_DEVICE,
1162 						attrs);
1163 
1164 				return ret;
1165 			}
1166 		}
1167 	}
1168 
1169 	ctlr->cur_rx_dma_dev = rx_dev;
1170 	ctlr->cur_tx_dma_dev = tx_dev;
1171 	ctlr->cur_msg_mapped = true;
1172 
1173 	return 0;
1174 }
1175 
__spi_unmap_msg(struct spi_controller * ctlr,struct spi_message * msg)1176 static int __spi_unmap_msg(struct spi_controller *ctlr, struct spi_message *msg)
1177 {
1178 	struct device *rx_dev = ctlr->cur_rx_dma_dev;
1179 	struct device *tx_dev = ctlr->cur_tx_dma_dev;
1180 	struct spi_transfer *xfer;
1181 
1182 	if (!ctlr->cur_msg_mapped || !ctlr->can_dma)
1183 		return 0;
1184 
1185 	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1186 		/* The sync has already been done after each transfer. */
1187 		unsigned long attrs = DMA_ATTR_SKIP_CPU_SYNC;
1188 
1189 		if (!ctlr->can_dma(ctlr, msg->spi, xfer))
1190 			continue;
1191 
1192 		spi_unmap_buf_attrs(ctlr, rx_dev, &xfer->rx_sg,
1193 				    DMA_FROM_DEVICE, attrs);
1194 		spi_unmap_buf_attrs(ctlr, tx_dev, &xfer->tx_sg,
1195 				    DMA_TO_DEVICE, attrs);
1196 	}
1197 
1198 	ctlr->cur_msg_mapped = false;
1199 
1200 	return 0;
1201 }
1202 
spi_dma_sync_for_device(struct spi_controller * ctlr,struct spi_transfer * xfer)1203 static void spi_dma_sync_for_device(struct spi_controller *ctlr,
1204 				    struct spi_transfer *xfer)
1205 {
1206 	struct device *rx_dev = ctlr->cur_rx_dma_dev;
1207 	struct device *tx_dev = ctlr->cur_tx_dma_dev;
1208 
1209 	if (!ctlr->cur_msg_mapped)
1210 		return;
1211 
1212 	if (xfer->tx_sg.orig_nents)
1213 		dma_sync_sgtable_for_device(tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
1214 	if (xfer->rx_sg.orig_nents)
1215 		dma_sync_sgtable_for_device(rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
1216 }
1217 
spi_dma_sync_for_cpu(struct spi_controller * ctlr,struct spi_transfer * xfer)1218 static void spi_dma_sync_for_cpu(struct spi_controller *ctlr,
1219 				 struct spi_transfer *xfer)
1220 {
1221 	struct device *rx_dev = ctlr->cur_rx_dma_dev;
1222 	struct device *tx_dev = ctlr->cur_tx_dma_dev;
1223 
1224 	if (!ctlr->cur_msg_mapped)
1225 		return;
1226 
1227 	if (xfer->rx_sg.orig_nents)
1228 		dma_sync_sgtable_for_cpu(rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
1229 	if (xfer->tx_sg.orig_nents)
1230 		dma_sync_sgtable_for_cpu(tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
1231 }
1232 #else /* !CONFIG_HAS_DMA */
__spi_map_msg(struct spi_controller * ctlr,struct spi_message * msg)1233 static inline int __spi_map_msg(struct spi_controller *ctlr,
1234 				struct spi_message *msg)
1235 {
1236 	return 0;
1237 }
1238 
__spi_unmap_msg(struct spi_controller * ctlr,struct spi_message * msg)1239 static inline int __spi_unmap_msg(struct spi_controller *ctlr,
1240 				  struct spi_message *msg)
1241 {
1242 	return 0;
1243 }
1244 
spi_dma_sync_for_device(struct spi_controller * ctrl,struct spi_transfer * xfer)1245 static void spi_dma_sync_for_device(struct spi_controller *ctrl,
1246 				    struct spi_transfer *xfer)
1247 {
1248 }
1249 
spi_dma_sync_for_cpu(struct spi_controller * ctrl,struct spi_transfer * xfer)1250 static void spi_dma_sync_for_cpu(struct spi_controller *ctrl,
1251 				 struct spi_transfer *xfer)
1252 {
1253 }
1254 #endif /* !CONFIG_HAS_DMA */
1255 
spi_unmap_msg(struct spi_controller * ctlr,struct spi_message * msg)1256 static inline int spi_unmap_msg(struct spi_controller *ctlr,
1257 				struct spi_message *msg)
1258 {
1259 	struct spi_transfer *xfer;
1260 
1261 	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1262 		/*
1263 		 * Restore the original value of tx_buf or rx_buf if they are
1264 		 * NULL.
1265 		 */
1266 		if (xfer->tx_buf == ctlr->dummy_tx)
1267 			xfer->tx_buf = NULL;
1268 		if (xfer->rx_buf == ctlr->dummy_rx)
1269 			xfer->rx_buf = NULL;
1270 	}
1271 
1272 	return __spi_unmap_msg(ctlr, msg);
1273 }
1274 
spi_map_msg(struct spi_controller * ctlr,struct spi_message * msg)1275 static int spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
1276 {
1277 	struct spi_transfer *xfer;
1278 	void *tmp;
1279 	unsigned int max_tx, max_rx;
1280 
1281 	if ((ctlr->flags & (SPI_CONTROLLER_MUST_RX | SPI_CONTROLLER_MUST_TX))
1282 		&& !(msg->spi->mode & SPI_3WIRE)) {
1283 		max_tx = 0;
1284 		max_rx = 0;
1285 
1286 		list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1287 			if ((ctlr->flags & SPI_CONTROLLER_MUST_TX) &&
1288 			    !xfer->tx_buf)
1289 				max_tx = max(xfer->len, max_tx);
1290 			if ((ctlr->flags & SPI_CONTROLLER_MUST_RX) &&
1291 			    !xfer->rx_buf)
1292 				max_rx = max(xfer->len, max_rx);
1293 		}
1294 
1295 		if (max_tx) {
1296 			tmp = krealloc(ctlr->dummy_tx, max_tx,
1297 				       GFP_KERNEL | GFP_DMA | __GFP_ZERO);
1298 			if (!tmp)
1299 				return -ENOMEM;
1300 			ctlr->dummy_tx = tmp;
1301 		}
1302 
1303 		if (max_rx) {
1304 			tmp = krealloc(ctlr->dummy_rx, max_rx,
1305 				       GFP_KERNEL | GFP_DMA);
1306 			if (!tmp)
1307 				return -ENOMEM;
1308 			ctlr->dummy_rx = tmp;
1309 		}
1310 
1311 		if (max_tx || max_rx) {
1312 			list_for_each_entry(xfer, &msg->transfers,
1313 					    transfer_list) {
1314 				if (!xfer->len)
1315 					continue;
1316 				if (!xfer->tx_buf)
1317 					xfer->tx_buf = ctlr->dummy_tx;
1318 				if (!xfer->rx_buf)
1319 					xfer->rx_buf = ctlr->dummy_rx;
1320 			}
1321 		}
1322 	}
1323 
1324 	return __spi_map_msg(ctlr, msg);
1325 }
1326 
spi_transfer_wait(struct spi_controller * ctlr,struct spi_message * msg,struct spi_transfer * xfer)1327 static int spi_transfer_wait(struct spi_controller *ctlr,
1328 			     struct spi_message *msg,
1329 			     struct spi_transfer *xfer)
1330 {
1331 	struct spi_statistics __percpu *statm = ctlr->pcpu_statistics;
1332 	struct spi_statistics __percpu *stats = msg->spi->pcpu_statistics;
1333 	u32 speed_hz = xfer->speed_hz;
1334 	unsigned long long ms;
1335 
1336 	if (spi_controller_is_slave(ctlr)) {
1337 		if (wait_for_completion_interruptible(&ctlr->xfer_completion)) {
1338 			dev_dbg(&msg->spi->dev, "SPI transfer interrupted\n");
1339 			return -EINTR;
1340 		}
1341 	} else {
1342 		if (!speed_hz)
1343 			speed_hz = 100000;
1344 
1345 		/*
1346 		 * For each byte we wait for 8 cycles of the SPI clock.
1347 		 * Since speed is defined in Hz and we want milliseconds,
1348 		 * use respective multiplier, but before the division,
1349 		 * otherwise we may get 0 for short transfers.
1350 		 */
1351 		ms = 8LL * MSEC_PER_SEC * xfer->len;
1352 		do_div(ms, speed_hz);
1353 
1354 		/*
1355 		 * Increase it twice and add 200 ms tolerance, use
1356 		 * predefined maximum in case of overflow.
1357 		 */
1358 		ms += ms + 200;
1359 		if (ms > UINT_MAX)
1360 			ms = UINT_MAX;
1361 
1362 		ms = wait_for_completion_timeout(&ctlr->xfer_completion,
1363 						 msecs_to_jiffies(ms));
1364 
1365 		if (ms == 0) {
1366 			SPI_STATISTICS_INCREMENT_FIELD(statm, timedout);
1367 			SPI_STATISTICS_INCREMENT_FIELD(stats, timedout);
1368 			dev_err(&msg->spi->dev,
1369 				"SPI transfer timed out\n");
1370 			return -ETIMEDOUT;
1371 		}
1372 	}
1373 
1374 	return 0;
1375 }
1376 
_spi_transfer_delay_ns(u32 ns)1377 static void _spi_transfer_delay_ns(u32 ns)
1378 {
1379 	if (!ns)
1380 		return;
1381 	if (ns <= NSEC_PER_USEC) {
1382 		ndelay(ns);
1383 	} else {
1384 		u32 us = DIV_ROUND_UP(ns, NSEC_PER_USEC);
1385 
1386 		if (us <= 10)
1387 			udelay(us);
1388 		else
1389 			usleep_range(us, us + DIV_ROUND_UP(us, 10));
1390 	}
1391 }
1392 
spi_delay_to_ns(struct spi_delay * _delay,struct spi_transfer * xfer)1393 int spi_delay_to_ns(struct spi_delay *_delay, struct spi_transfer *xfer)
1394 {
1395 	u32 delay = _delay->value;
1396 	u32 unit = _delay->unit;
1397 	u32 hz;
1398 
1399 	if (!delay)
1400 		return 0;
1401 
1402 	switch (unit) {
1403 	case SPI_DELAY_UNIT_USECS:
1404 		delay *= NSEC_PER_USEC;
1405 		break;
1406 	case SPI_DELAY_UNIT_NSECS:
1407 		/* Nothing to do here */
1408 		break;
1409 	case SPI_DELAY_UNIT_SCK:
1410 		/* Clock cycles need to be obtained from spi_transfer */
1411 		if (!xfer)
1412 			return -EINVAL;
1413 		/*
1414 		 * If there is unknown effective speed, approximate it
1415 		 * by underestimating with half of the requested hz.
1416 		 */
1417 		hz = xfer->effective_speed_hz ?: xfer->speed_hz / 2;
1418 		if (!hz)
1419 			return -EINVAL;
1420 
1421 		/* Convert delay to nanoseconds */
1422 		delay *= DIV_ROUND_UP(NSEC_PER_SEC, hz);
1423 		break;
1424 	default:
1425 		return -EINVAL;
1426 	}
1427 
1428 	return delay;
1429 }
1430 EXPORT_SYMBOL_GPL(spi_delay_to_ns);
1431 
spi_delay_exec(struct spi_delay * _delay,struct spi_transfer * xfer)1432 int spi_delay_exec(struct spi_delay *_delay, struct spi_transfer *xfer)
1433 {
1434 	int delay;
1435 
1436 	might_sleep();
1437 
1438 	if (!_delay)
1439 		return -EINVAL;
1440 
1441 	delay = spi_delay_to_ns(_delay, xfer);
1442 	if (delay < 0)
1443 		return delay;
1444 
1445 	_spi_transfer_delay_ns(delay);
1446 
1447 	return 0;
1448 }
1449 EXPORT_SYMBOL_GPL(spi_delay_exec);
1450 
_spi_transfer_cs_change_delay(struct spi_message * msg,struct spi_transfer * xfer)1451 static void _spi_transfer_cs_change_delay(struct spi_message *msg,
1452 					  struct spi_transfer *xfer)
1453 {
1454 	u32 default_delay_ns = 10 * NSEC_PER_USEC;
1455 	u32 delay = xfer->cs_change_delay.value;
1456 	u32 unit = xfer->cs_change_delay.unit;
1457 	int ret;
1458 
1459 	/* Return early on "fast" mode - for everything but USECS */
1460 	if (!delay) {
1461 		if (unit == SPI_DELAY_UNIT_USECS)
1462 			_spi_transfer_delay_ns(default_delay_ns);
1463 		return;
1464 	}
1465 
1466 	ret = spi_delay_exec(&xfer->cs_change_delay, xfer);
1467 	if (ret) {
1468 		dev_err_once(&msg->spi->dev,
1469 			     "Use of unsupported delay unit %i, using default of %luus\n",
1470 			     unit, default_delay_ns / NSEC_PER_USEC);
1471 		_spi_transfer_delay_ns(default_delay_ns);
1472 	}
1473 }
1474 
1475 /*
1476  * spi_transfer_one_message - Default implementation of transfer_one_message()
1477  *
1478  * This is a standard implementation of transfer_one_message() for
1479  * drivers which implement a transfer_one() operation.  It provides
1480  * standard handling of delays and chip select management.
1481  */
spi_transfer_one_message(struct spi_controller * ctlr,struct spi_message * msg)1482 static int spi_transfer_one_message(struct spi_controller *ctlr,
1483 				    struct spi_message *msg)
1484 {
1485 	struct spi_transfer *xfer;
1486 	bool keep_cs = false;
1487 	int ret = 0;
1488 	struct spi_statistics __percpu *statm = ctlr->pcpu_statistics;
1489 	struct spi_statistics __percpu *stats = msg->spi->pcpu_statistics;
1490 
1491 	xfer = list_first_entry(&msg->transfers, struct spi_transfer, transfer_list);
1492 	spi_set_cs(msg->spi, !xfer->cs_off, false);
1493 
1494 	SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
1495 	SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
1496 
1497 	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1498 		trace_spi_transfer_start(msg, xfer);
1499 
1500 		spi_statistics_add_transfer_stats(statm, xfer, ctlr);
1501 		spi_statistics_add_transfer_stats(stats, xfer, ctlr);
1502 
1503 		if (!ctlr->ptp_sts_supported) {
1504 			xfer->ptp_sts_word_pre = 0;
1505 			ptp_read_system_prets(xfer->ptp_sts);
1506 		}
1507 
1508 		if ((xfer->tx_buf || xfer->rx_buf) && xfer->len) {
1509 			reinit_completion(&ctlr->xfer_completion);
1510 
1511 fallback_pio:
1512 			spi_dma_sync_for_device(ctlr, xfer);
1513 			ret = ctlr->transfer_one(ctlr, msg->spi, xfer);
1514 			if (ret < 0) {
1515 				spi_dma_sync_for_cpu(ctlr, xfer);
1516 
1517 				if (ctlr->cur_msg_mapped &&
1518 				   (xfer->error & SPI_TRANS_FAIL_NO_START)) {
1519 					__spi_unmap_msg(ctlr, msg);
1520 					ctlr->fallback = true;
1521 					xfer->error &= ~SPI_TRANS_FAIL_NO_START;
1522 					goto fallback_pio;
1523 				}
1524 
1525 				SPI_STATISTICS_INCREMENT_FIELD(statm,
1526 							       errors);
1527 				SPI_STATISTICS_INCREMENT_FIELD(stats,
1528 							       errors);
1529 				dev_err(&msg->spi->dev,
1530 					"SPI transfer failed: %d\n", ret);
1531 				goto out;
1532 			}
1533 
1534 			if (ret > 0) {
1535 				ret = spi_transfer_wait(ctlr, msg, xfer);
1536 				if (ret < 0)
1537 					msg->status = ret;
1538 			}
1539 
1540 			spi_dma_sync_for_cpu(ctlr, xfer);
1541 		} else {
1542 			if (xfer->len)
1543 				dev_err(&msg->spi->dev,
1544 					"Bufferless transfer has length %u\n",
1545 					xfer->len);
1546 		}
1547 
1548 		if (!ctlr->ptp_sts_supported) {
1549 			ptp_read_system_postts(xfer->ptp_sts);
1550 			xfer->ptp_sts_word_post = xfer->len;
1551 		}
1552 
1553 		trace_spi_transfer_stop(msg, xfer);
1554 
1555 		if (msg->status != -EINPROGRESS)
1556 			goto out;
1557 
1558 		spi_transfer_delay_exec(xfer);
1559 
1560 		if (xfer->cs_change) {
1561 			if (list_is_last(&xfer->transfer_list,
1562 					 &msg->transfers)) {
1563 				keep_cs = true;
1564 			} else {
1565 				if (!xfer->cs_off)
1566 					spi_set_cs(msg->spi, false, false);
1567 				_spi_transfer_cs_change_delay(msg, xfer);
1568 				if (!list_next_entry(xfer, transfer_list)->cs_off)
1569 					spi_set_cs(msg->spi, true, false);
1570 			}
1571 		} else if (!list_is_last(&xfer->transfer_list, &msg->transfers) &&
1572 			   xfer->cs_off != list_next_entry(xfer, transfer_list)->cs_off) {
1573 			spi_set_cs(msg->spi, xfer->cs_off, false);
1574 		}
1575 
1576 		msg->actual_length += xfer->len;
1577 	}
1578 
1579 out:
1580 	if (ret != 0 || !keep_cs)
1581 		spi_set_cs(msg->spi, false, false);
1582 
1583 	if (msg->status == -EINPROGRESS)
1584 		msg->status = ret;
1585 
1586 	if (msg->status && ctlr->handle_err)
1587 		ctlr->handle_err(ctlr, msg);
1588 
1589 	spi_finalize_current_message(ctlr);
1590 
1591 	return ret;
1592 }
1593 
1594 /**
1595  * spi_finalize_current_transfer - report completion of a transfer
1596  * @ctlr: the controller reporting completion
1597  *
1598  * Called by SPI drivers using the core transfer_one_message()
1599  * implementation to notify it that the current interrupt driven
1600  * transfer has finished and the next one may be scheduled.
1601  */
spi_finalize_current_transfer(struct spi_controller * ctlr)1602 void spi_finalize_current_transfer(struct spi_controller *ctlr)
1603 {
1604 	complete(&ctlr->xfer_completion);
1605 }
1606 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1607 
spi_idle_runtime_pm(struct spi_controller * ctlr)1608 static void spi_idle_runtime_pm(struct spi_controller *ctlr)
1609 {
1610 	if (ctlr->auto_runtime_pm) {
1611 		pm_runtime_mark_last_busy(ctlr->dev.parent);
1612 		pm_runtime_put_autosuspend(ctlr->dev.parent);
1613 	}
1614 }
1615 
__spi_pump_transfer_message(struct spi_controller * ctlr,struct spi_message * msg,bool was_busy)1616 static int __spi_pump_transfer_message(struct spi_controller *ctlr,
1617 		struct spi_message *msg, bool was_busy)
1618 {
1619 	struct spi_transfer *xfer;
1620 	int ret;
1621 
1622 	if (!was_busy && ctlr->auto_runtime_pm) {
1623 		ret = pm_runtime_get_sync(ctlr->dev.parent);
1624 		if (ret < 0) {
1625 			pm_runtime_put_noidle(ctlr->dev.parent);
1626 			dev_err(&ctlr->dev, "Failed to power device: %d\n",
1627 				ret);
1628 			return ret;
1629 		}
1630 	}
1631 
1632 	if (!was_busy)
1633 		trace_spi_controller_busy(ctlr);
1634 
1635 	if (!was_busy && ctlr->prepare_transfer_hardware) {
1636 		ret = ctlr->prepare_transfer_hardware(ctlr);
1637 		if (ret) {
1638 			dev_err(&ctlr->dev,
1639 				"failed to prepare transfer hardware: %d\n",
1640 				ret);
1641 
1642 			if (ctlr->auto_runtime_pm)
1643 				pm_runtime_put(ctlr->dev.parent);
1644 
1645 			msg->status = ret;
1646 			spi_finalize_current_message(ctlr);
1647 
1648 			return ret;
1649 		}
1650 	}
1651 
1652 	trace_spi_message_start(msg);
1653 
1654 	ret = spi_split_transfers_maxsize(ctlr, msg,
1655 					  spi_max_transfer_size(msg->spi),
1656 					  GFP_KERNEL | GFP_DMA);
1657 	if (ret) {
1658 		msg->status = ret;
1659 		spi_finalize_current_message(ctlr);
1660 		return ret;
1661 	}
1662 
1663 	if (ctlr->prepare_message) {
1664 		ret = ctlr->prepare_message(ctlr, msg);
1665 		if (ret) {
1666 			dev_err(&ctlr->dev, "failed to prepare message: %d\n",
1667 				ret);
1668 			msg->status = ret;
1669 			spi_finalize_current_message(ctlr);
1670 			return ret;
1671 		}
1672 		msg->prepared = true;
1673 	}
1674 
1675 	ret = spi_map_msg(ctlr, msg);
1676 	if (ret) {
1677 		msg->status = ret;
1678 		spi_finalize_current_message(ctlr);
1679 		return ret;
1680 	}
1681 
1682 	if (!ctlr->ptp_sts_supported && !ctlr->transfer_one) {
1683 		list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1684 			xfer->ptp_sts_word_pre = 0;
1685 			ptp_read_system_prets(xfer->ptp_sts);
1686 		}
1687 	}
1688 
1689 	/*
1690 	 * Drivers implementation of transfer_one_message() must arrange for
1691 	 * spi_finalize_current_message() to get called. Most drivers will do
1692 	 * this in the calling context, but some don't. For those cases, a
1693 	 * completion is used to guarantee that this function does not return
1694 	 * until spi_finalize_current_message() is done accessing
1695 	 * ctlr->cur_msg.
1696 	 * Use of the following two flags enable to opportunistically skip the
1697 	 * use of the completion since its use involves expensive spin locks.
1698 	 * In case of a race with the context that calls
1699 	 * spi_finalize_current_message() the completion will always be used,
1700 	 * due to strict ordering of these flags using barriers.
1701 	 */
1702 	WRITE_ONCE(ctlr->cur_msg_incomplete, true);
1703 	WRITE_ONCE(ctlr->cur_msg_need_completion, false);
1704 	reinit_completion(&ctlr->cur_msg_completion);
1705 	smp_wmb(); /* Make these available to spi_finalize_current_message() */
1706 
1707 	ret = ctlr->transfer_one_message(ctlr, msg);
1708 	if (ret) {
1709 		dev_err(&ctlr->dev,
1710 			"failed to transfer one message from queue\n");
1711 		return ret;
1712 	}
1713 
1714 	WRITE_ONCE(ctlr->cur_msg_need_completion, true);
1715 	smp_mb(); /* See spi_finalize_current_message()... */
1716 	if (READ_ONCE(ctlr->cur_msg_incomplete))
1717 		wait_for_completion(&ctlr->cur_msg_completion);
1718 
1719 	return 0;
1720 }
1721 
1722 /**
1723  * __spi_pump_messages - function which processes spi message queue
1724  * @ctlr: controller to process queue for
1725  * @in_kthread: true if we are in the context of the message pump thread
1726  *
1727  * This function checks if there is any spi message in the queue that
1728  * needs processing and if so call out to the driver to initialize hardware
1729  * and transfer each message.
1730  *
1731  * Note that it is called both from the kthread itself and also from
1732  * inside spi_sync(); the queue extraction handling at the top of the
1733  * function should deal with this safely.
1734  */
__spi_pump_messages(struct spi_controller * ctlr,bool in_kthread)1735 static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread)
1736 {
1737 	struct spi_message *msg;
1738 	bool was_busy = false;
1739 	unsigned long flags;
1740 	int ret;
1741 
1742 	/* Take the IO mutex */
1743 	mutex_lock(&ctlr->io_mutex);
1744 
1745 	/* Lock queue */
1746 	spin_lock_irqsave(&ctlr->queue_lock, flags);
1747 
1748 	/* Make sure we are not already running a message */
1749 	if (ctlr->cur_msg)
1750 		goto out_unlock;
1751 
1752 	/* Check if the queue is idle */
1753 	if (list_empty(&ctlr->queue) || !ctlr->running) {
1754 		if (!ctlr->busy)
1755 			goto out_unlock;
1756 
1757 		/* Defer any non-atomic teardown to the thread */
1758 		if (!in_kthread) {
1759 			if (!ctlr->dummy_rx && !ctlr->dummy_tx &&
1760 			    !ctlr->unprepare_transfer_hardware) {
1761 				spi_idle_runtime_pm(ctlr);
1762 				ctlr->busy = false;
1763 				ctlr->queue_empty = true;
1764 				trace_spi_controller_idle(ctlr);
1765 			} else {
1766 				kthread_queue_work(ctlr->kworker,
1767 						   &ctlr->pump_messages);
1768 			}
1769 			goto out_unlock;
1770 		}
1771 
1772 		ctlr->busy = false;
1773 		spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1774 
1775 		kfree(ctlr->dummy_rx);
1776 		ctlr->dummy_rx = NULL;
1777 		kfree(ctlr->dummy_tx);
1778 		ctlr->dummy_tx = NULL;
1779 		if (ctlr->unprepare_transfer_hardware &&
1780 		    ctlr->unprepare_transfer_hardware(ctlr))
1781 			dev_err(&ctlr->dev,
1782 				"failed to unprepare transfer hardware\n");
1783 		spi_idle_runtime_pm(ctlr);
1784 		trace_spi_controller_idle(ctlr);
1785 
1786 		spin_lock_irqsave(&ctlr->queue_lock, flags);
1787 		ctlr->queue_empty = true;
1788 		goto out_unlock;
1789 	}
1790 
1791 	/* Extract head of queue */
1792 	msg = list_first_entry(&ctlr->queue, struct spi_message, queue);
1793 	ctlr->cur_msg = msg;
1794 
1795 	list_del_init(&msg->queue);
1796 	if (ctlr->busy)
1797 		was_busy = true;
1798 	else
1799 		ctlr->busy = true;
1800 	spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1801 
1802 	ret = __spi_pump_transfer_message(ctlr, msg, was_busy);
1803 	kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
1804 
1805 	ctlr->cur_msg = NULL;
1806 	ctlr->fallback = false;
1807 
1808 	mutex_unlock(&ctlr->io_mutex);
1809 
1810 	/* Prod the scheduler in case transfer_one() was busy waiting */
1811 	if (!ret)
1812 		cond_resched();
1813 	return;
1814 
1815 out_unlock:
1816 	spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1817 	mutex_unlock(&ctlr->io_mutex);
1818 }
1819 
1820 /**
1821  * spi_pump_messages - kthread work function which processes spi message queue
1822  * @work: pointer to kthread work struct contained in the controller struct
1823  */
spi_pump_messages(struct kthread_work * work)1824 static void spi_pump_messages(struct kthread_work *work)
1825 {
1826 	struct spi_controller *ctlr =
1827 		container_of(work, struct spi_controller, pump_messages);
1828 
1829 	__spi_pump_messages(ctlr, true);
1830 }
1831 
1832 /**
1833  * spi_take_timestamp_pre - helper to collect the beginning of the TX timestamp
1834  * @ctlr: Pointer to the spi_controller structure of the driver
1835  * @xfer: Pointer to the transfer being timestamped
1836  * @progress: How many words (not bytes) have been transferred so far
1837  * @irqs_off: If true, will disable IRQs and preemption for the duration of the
1838  *	      transfer, for less jitter in time measurement. Only compatible
1839  *	      with PIO drivers. If true, must follow up with
1840  *	      spi_take_timestamp_post or otherwise system will crash.
1841  *	      WARNING: for fully predictable results, the CPU frequency must
1842  *	      also be under control (governor).
1843  *
1844  * This is a helper for drivers to collect the beginning of the TX timestamp
1845  * for the requested byte from the SPI transfer. The frequency with which this
1846  * function must be called (once per word, once for the whole transfer, once
1847  * per batch of words etc) is arbitrary as long as the @tx buffer offset is
1848  * greater than or equal to the requested byte at the time of the call. The
1849  * timestamp is only taken once, at the first such call. It is assumed that
1850  * the driver advances its @tx buffer pointer monotonically.
1851  */
spi_take_timestamp_pre(struct spi_controller * ctlr,struct spi_transfer * xfer,size_t progress,bool irqs_off)1852 void spi_take_timestamp_pre(struct spi_controller *ctlr,
1853 			    struct spi_transfer *xfer,
1854 			    size_t progress, bool irqs_off)
1855 {
1856 	if (!xfer->ptp_sts)
1857 		return;
1858 
1859 	if (xfer->timestamped)
1860 		return;
1861 
1862 	if (progress > xfer->ptp_sts_word_pre)
1863 		return;
1864 
1865 	/* Capture the resolution of the timestamp */
1866 	xfer->ptp_sts_word_pre = progress;
1867 
1868 	if (irqs_off) {
1869 		local_irq_save(ctlr->irq_flags);
1870 		preempt_disable();
1871 	}
1872 
1873 	ptp_read_system_prets(xfer->ptp_sts);
1874 }
1875 EXPORT_SYMBOL_GPL(spi_take_timestamp_pre);
1876 
1877 /**
1878  * spi_take_timestamp_post - helper to collect the end of the TX timestamp
1879  * @ctlr: Pointer to the spi_controller structure of the driver
1880  * @xfer: Pointer to the transfer being timestamped
1881  * @progress: How many words (not bytes) have been transferred so far
1882  * @irqs_off: If true, will re-enable IRQs and preemption for the local CPU.
1883  *
1884  * This is a helper for drivers to collect the end of the TX timestamp for
1885  * the requested byte from the SPI transfer. Can be called with an arbitrary
1886  * frequency: only the first call where @tx exceeds or is equal to the
1887  * requested word will be timestamped.
1888  */
spi_take_timestamp_post(struct spi_controller * ctlr,struct spi_transfer * xfer,size_t progress,bool irqs_off)1889 void spi_take_timestamp_post(struct spi_controller *ctlr,
1890 			     struct spi_transfer *xfer,
1891 			     size_t progress, bool irqs_off)
1892 {
1893 	if (!xfer->ptp_sts)
1894 		return;
1895 
1896 	if (xfer->timestamped)
1897 		return;
1898 
1899 	if (progress < xfer->ptp_sts_word_post)
1900 		return;
1901 
1902 	ptp_read_system_postts(xfer->ptp_sts);
1903 
1904 	if (irqs_off) {
1905 		local_irq_restore(ctlr->irq_flags);
1906 		preempt_enable();
1907 	}
1908 
1909 	/* Capture the resolution of the timestamp */
1910 	xfer->ptp_sts_word_post = progress;
1911 
1912 	xfer->timestamped = true;
1913 }
1914 EXPORT_SYMBOL_GPL(spi_take_timestamp_post);
1915 
1916 /**
1917  * spi_set_thread_rt - set the controller to pump at realtime priority
1918  * @ctlr: controller to boost priority of
1919  *
1920  * This can be called because the controller requested realtime priority
1921  * (by setting the ->rt value before calling spi_register_controller()) or
1922  * because a device on the bus said that its transfers needed realtime
1923  * priority.
1924  *
1925  * NOTE: at the moment if any device on a bus says it needs realtime then
1926  * the thread will be at realtime priority for all transfers on that
1927  * controller.  If this eventually becomes a problem we may see if we can
1928  * find a way to boost the priority only temporarily during relevant
1929  * transfers.
1930  */
spi_set_thread_rt(struct spi_controller * ctlr)1931 static void spi_set_thread_rt(struct spi_controller *ctlr)
1932 {
1933 	dev_info(&ctlr->dev,
1934 		"will run message pump with realtime priority\n");
1935 	sched_set_fifo(ctlr->kworker->task);
1936 }
1937 
spi_init_queue(struct spi_controller * ctlr)1938 static int spi_init_queue(struct spi_controller *ctlr)
1939 {
1940 	ctlr->running = false;
1941 	ctlr->busy = false;
1942 	ctlr->queue_empty = true;
1943 
1944 	ctlr->kworker = kthread_create_worker(0, dev_name(&ctlr->dev));
1945 	if (IS_ERR(ctlr->kworker)) {
1946 		dev_err(&ctlr->dev, "failed to create message pump kworker\n");
1947 		return PTR_ERR(ctlr->kworker);
1948 	}
1949 
1950 	kthread_init_work(&ctlr->pump_messages, spi_pump_messages);
1951 
1952 	/*
1953 	 * Controller config will indicate if this controller should run the
1954 	 * message pump with high (realtime) priority to reduce the transfer
1955 	 * latency on the bus by minimising the delay between a transfer
1956 	 * request and the scheduling of the message pump thread. Without this
1957 	 * setting the message pump thread will remain at default priority.
1958 	 */
1959 	if (ctlr->rt)
1960 		spi_set_thread_rt(ctlr);
1961 
1962 	return 0;
1963 }
1964 
1965 /**
1966  * spi_get_next_queued_message() - called by driver to check for queued
1967  * messages
1968  * @ctlr: the controller to check for queued messages
1969  *
1970  * If there are more messages in the queue, the next message is returned from
1971  * this call.
1972  *
1973  * Return: the next message in the queue, else NULL if the queue is empty.
1974  */
spi_get_next_queued_message(struct spi_controller * ctlr)1975 struct spi_message *spi_get_next_queued_message(struct spi_controller *ctlr)
1976 {
1977 	struct spi_message *next;
1978 	unsigned long flags;
1979 
1980 	/* Get a pointer to the next message, if any */
1981 	spin_lock_irqsave(&ctlr->queue_lock, flags);
1982 	next = list_first_entry_or_null(&ctlr->queue, struct spi_message,
1983 					queue);
1984 	spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1985 
1986 	return next;
1987 }
1988 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1989 
1990 /**
1991  * spi_finalize_current_message() - the current message is complete
1992  * @ctlr: the controller to return the message to
1993  *
1994  * Called by the driver to notify the core that the message in the front of the
1995  * queue is complete and can be removed from the queue.
1996  */
spi_finalize_current_message(struct spi_controller * ctlr)1997 void spi_finalize_current_message(struct spi_controller *ctlr)
1998 {
1999 	struct spi_transfer *xfer;
2000 	struct spi_message *mesg;
2001 	int ret;
2002 
2003 	mesg = ctlr->cur_msg;
2004 
2005 	if (!ctlr->ptp_sts_supported && !ctlr->transfer_one) {
2006 		list_for_each_entry(xfer, &mesg->transfers, transfer_list) {
2007 			ptp_read_system_postts(xfer->ptp_sts);
2008 			xfer->ptp_sts_word_post = xfer->len;
2009 		}
2010 	}
2011 
2012 	if (unlikely(ctlr->ptp_sts_supported))
2013 		list_for_each_entry(xfer, &mesg->transfers, transfer_list)
2014 			WARN_ON_ONCE(xfer->ptp_sts && !xfer->timestamped);
2015 
2016 	spi_unmap_msg(ctlr, mesg);
2017 
2018 	/*
2019 	 * In the prepare_messages callback the SPI bus has the opportunity
2020 	 * to split a transfer to smaller chunks.
2021 	 *
2022 	 * Release the split transfers here since spi_map_msg() is done on
2023 	 * the split transfers.
2024 	 */
2025 	spi_res_release(ctlr, mesg);
2026 
2027 	if (mesg->prepared && ctlr->unprepare_message) {
2028 		ret = ctlr->unprepare_message(ctlr, mesg);
2029 		if (ret) {
2030 			dev_err(&ctlr->dev, "failed to unprepare message: %d\n",
2031 				ret);
2032 		}
2033 	}
2034 
2035 	mesg->prepared = false;
2036 
2037 	WRITE_ONCE(ctlr->cur_msg_incomplete, false);
2038 	smp_mb(); /* See __spi_pump_transfer_message()... */
2039 	if (READ_ONCE(ctlr->cur_msg_need_completion))
2040 		complete(&ctlr->cur_msg_completion);
2041 
2042 	trace_spi_message_done(mesg);
2043 
2044 	mesg->state = NULL;
2045 	if (mesg->complete)
2046 		mesg->complete(mesg->context);
2047 }
2048 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
2049 
spi_start_queue(struct spi_controller * ctlr)2050 static int spi_start_queue(struct spi_controller *ctlr)
2051 {
2052 	unsigned long flags;
2053 
2054 	spin_lock_irqsave(&ctlr->queue_lock, flags);
2055 
2056 	if (ctlr->running || ctlr->busy) {
2057 		spin_unlock_irqrestore(&ctlr->queue_lock, flags);
2058 		return -EBUSY;
2059 	}
2060 
2061 	ctlr->running = true;
2062 	ctlr->cur_msg = NULL;
2063 	spin_unlock_irqrestore(&ctlr->queue_lock, flags);
2064 
2065 	kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
2066 
2067 	return 0;
2068 }
2069 
spi_stop_queue(struct spi_controller * ctlr)2070 static int spi_stop_queue(struct spi_controller *ctlr)
2071 {
2072 	unsigned long flags;
2073 	unsigned limit = 500;
2074 	int ret = 0;
2075 
2076 	spin_lock_irqsave(&ctlr->queue_lock, flags);
2077 
2078 	/*
2079 	 * This is a bit lame, but is optimized for the common execution path.
2080 	 * A wait_queue on the ctlr->busy could be used, but then the common
2081 	 * execution path (pump_messages) would be required to call wake_up or
2082 	 * friends on every SPI message. Do this instead.
2083 	 */
2084 	while ((!list_empty(&ctlr->queue) || ctlr->busy) && limit--) {
2085 		spin_unlock_irqrestore(&ctlr->queue_lock, flags);
2086 		usleep_range(10000, 11000);
2087 		spin_lock_irqsave(&ctlr->queue_lock, flags);
2088 	}
2089 
2090 	if (!list_empty(&ctlr->queue) || ctlr->busy)
2091 		ret = -EBUSY;
2092 	else
2093 		ctlr->running = false;
2094 
2095 	spin_unlock_irqrestore(&ctlr->queue_lock, flags);
2096 
2097 	if (ret) {
2098 		dev_warn(&ctlr->dev, "could not stop message queue\n");
2099 		return ret;
2100 	}
2101 	return ret;
2102 }
2103 
spi_destroy_queue(struct spi_controller * ctlr)2104 static int spi_destroy_queue(struct spi_controller *ctlr)
2105 {
2106 	int ret;
2107 
2108 	ret = spi_stop_queue(ctlr);
2109 
2110 	/*
2111 	 * kthread_flush_worker will block until all work is done.
2112 	 * If the reason that stop_queue timed out is that the work will never
2113 	 * finish, then it does no good to call flush/stop thread, so
2114 	 * return anyway.
2115 	 */
2116 	if (ret) {
2117 		dev_err(&ctlr->dev, "problem destroying queue\n");
2118 		return ret;
2119 	}
2120 
2121 	kthread_destroy_worker(ctlr->kworker);
2122 
2123 	return 0;
2124 }
2125 
__spi_queued_transfer(struct spi_device * spi,struct spi_message * msg,bool need_pump)2126 static int __spi_queued_transfer(struct spi_device *spi,
2127 				 struct spi_message *msg,
2128 				 bool need_pump)
2129 {
2130 	struct spi_controller *ctlr = spi->controller;
2131 	unsigned long flags;
2132 
2133 	spin_lock_irqsave(&ctlr->queue_lock, flags);
2134 
2135 	if (!ctlr->running) {
2136 		spin_unlock_irqrestore(&ctlr->queue_lock, flags);
2137 		return -ESHUTDOWN;
2138 	}
2139 	msg->actual_length = 0;
2140 	msg->status = -EINPROGRESS;
2141 
2142 	list_add_tail(&msg->queue, &ctlr->queue);
2143 	ctlr->queue_empty = false;
2144 	if (!ctlr->busy && need_pump)
2145 		kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
2146 
2147 	spin_unlock_irqrestore(&ctlr->queue_lock, flags);
2148 	return 0;
2149 }
2150 
2151 /**
2152  * spi_queued_transfer - transfer function for queued transfers
2153  * @spi: spi device which is requesting transfer
2154  * @msg: spi message which is to handled is queued to driver queue
2155  *
2156  * Return: zero on success, else a negative error code.
2157  */
spi_queued_transfer(struct spi_device * spi,struct spi_message * msg)2158 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
2159 {
2160 	return __spi_queued_transfer(spi, msg, true);
2161 }
2162 
spi_controller_initialize_queue(struct spi_controller * ctlr)2163 static int spi_controller_initialize_queue(struct spi_controller *ctlr)
2164 {
2165 	int ret;
2166 
2167 	ctlr->transfer = spi_queued_transfer;
2168 	if (!ctlr->transfer_one_message)
2169 		ctlr->transfer_one_message = spi_transfer_one_message;
2170 
2171 	/* Initialize and start queue */
2172 	ret = spi_init_queue(ctlr);
2173 	if (ret) {
2174 		dev_err(&ctlr->dev, "problem initializing queue\n");
2175 		goto err_init_queue;
2176 	}
2177 	ctlr->queued = true;
2178 	ret = spi_start_queue(ctlr);
2179 	if (ret) {
2180 		dev_err(&ctlr->dev, "problem starting queue\n");
2181 		goto err_start_queue;
2182 	}
2183 
2184 	return 0;
2185 
2186 err_start_queue:
2187 	spi_destroy_queue(ctlr);
2188 err_init_queue:
2189 	return ret;
2190 }
2191 
2192 /**
2193  * spi_flush_queue - Send all pending messages in the queue from the callers'
2194  *		     context
2195  * @ctlr: controller to process queue for
2196  *
2197  * This should be used when one wants to ensure all pending messages have been
2198  * sent before doing something. Is used by the spi-mem code to make sure SPI
2199  * memory operations do not preempt regular SPI transfers that have been queued
2200  * before the spi-mem operation.
2201  */
spi_flush_queue(struct spi_controller * ctlr)2202 void spi_flush_queue(struct spi_controller *ctlr)
2203 {
2204 	if (ctlr->transfer == spi_queued_transfer)
2205 		__spi_pump_messages(ctlr, false);
2206 }
2207 
2208 /*-------------------------------------------------------------------------*/
2209 
2210 #if defined(CONFIG_OF)
of_spi_parse_dt(struct spi_controller * ctlr,struct spi_device * spi,struct device_node * nc)2211 static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi,
2212 			   struct device_node *nc)
2213 {
2214 	u32 value;
2215 	int rc;
2216 
2217 	/* Mode (clock phase/polarity/etc.) */
2218 	if (of_property_read_bool(nc, "spi-cpha"))
2219 		spi->mode |= SPI_CPHA;
2220 	if (of_property_read_bool(nc, "spi-cpol"))
2221 		spi->mode |= SPI_CPOL;
2222 	if (of_property_read_bool(nc, "spi-3wire"))
2223 		spi->mode |= SPI_3WIRE;
2224 	if (of_property_read_bool(nc, "spi-lsb-first"))
2225 		spi->mode |= SPI_LSB_FIRST;
2226 	if (of_property_read_bool(nc, "spi-cs-high"))
2227 		spi->mode |= SPI_CS_HIGH;
2228 
2229 	/* Device DUAL/QUAD mode */
2230 	if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
2231 		switch (value) {
2232 		case 0:
2233 			spi->mode |= SPI_NO_TX;
2234 			break;
2235 		case 1:
2236 			break;
2237 		case 2:
2238 			spi->mode |= SPI_TX_DUAL;
2239 			break;
2240 		case 4:
2241 			spi->mode |= SPI_TX_QUAD;
2242 			break;
2243 		case 8:
2244 			spi->mode |= SPI_TX_OCTAL;
2245 			break;
2246 		default:
2247 			dev_warn(&ctlr->dev,
2248 				"spi-tx-bus-width %d not supported\n",
2249 				value);
2250 			break;
2251 		}
2252 	}
2253 
2254 	if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
2255 		switch (value) {
2256 		case 0:
2257 			spi->mode |= SPI_NO_RX;
2258 			break;
2259 		case 1:
2260 			break;
2261 		case 2:
2262 			spi->mode |= SPI_RX_DUAL;
2263 			break;
2264 		case 4:
2265 			spi->mode |= SPI_RX_QUAD;
2266 			break;
2267 		case 8:
2268 			spi->mode |= SPI_RX_OCTAL;
2269 			break;
2270 		default:
2271 			dev_warn(&ctlr->dev,
2272 				"spi-rx-bus-width %d not supported\n",
2273 				value);
2274 			break;
2275 		}
2276 	}
2277 
2278 	if (spi_controller_is_slave(ctlr)) {
2279 		if (!of_node_name_eq(nc, "slave")) {
2280 			dev_err(&ctlr->dev, "%pOF is not called 'slave'\n",
2281 				nc);
2282 			return -EINVAL;
2283 		}
2284 		return 0;
2285 	}
2286 
2287 	/* Device address */
2288 	rc = of_property_read_u32(nc, "reg", &value);
2289 	if (rc) {
2290 		dev_err(&ctlr->dev, "%pOF has no valid 'reg' property (%d)\n",
2291 			nc, rc);
2292 		return rc;
2293 	}
2294 	spi->chip_select = value;
2295 
2296 	/* Device speed */
2297 	if (!of_property_read_u32(nc, "spi-max-frequency", &value))
2298 		spi->max_speed_hz = value;
2299 
2300 	return 0;
2301 }
2302 
2303 static struct spi_device *
of_register_spi_device(struct spi_controller * ctlr,struct device_node * nc)2304 of_register_spi_device(struct spi_controller *ctlr, struct device_node *nc)
2305 {
2306 	struct spi_device *spi;
2307 	int rc;
2308 
2309 	/* Alloc an spi_device */
2310 	spi = spi_alloc_device(ctlr);
2311 	if (!spi) {
2312 		dev_err(&ctlr->dev, "spi_device alloc error for %pOF\n", nc);
2313 		rc = -ENOMEM;
2314 		goto err_out;
2315 	}
2316 
2317 	/* Select device driver */
2318 	rc = of_modalias_node(nc, spi->modalias,
2319 				sizeof(spi->modalias));
2320 	if (rc < 0) {
2321 		dev_err(&ctlr->dev, "cannot find modalias for %pOF\n", nc);
2322 		goto err_out;
2323 	}
2324 
2325 	rc = of_spi_parse_dt(ctlr, spi, nc);
2326 	if (rc)
2327 		goto err_out;
2328 
2329 	/* Store a pointer to the node in the device structure */
2330 	of_node_get(nc);
2331 	spi->dev.of_node = nc;
2332 	spi->dev.fwnode = of_fwnode_handle(nc);
2333 
2334 	/* Register the new device */
2335 	rc = spi_add_device(spi);
2336 	if (rc) {
2337 		dev_err(&ctlr->dev, "spi_device register error %pOF\n", nc);
2338 		goto err_of_node_put;
2339 	}
2340 
2341 	return spi;
2342 
2343 err_of_node_put:
2344 	of_node_put(nc);
2345 err_out:
2346 	spi_dev_put(spi);
2347 	return ERR_PTR(rc);
2348 }
2349 
2350 /**
2351  * of_register_spi_devices() - Register child devices onto the SPI bus
2352  * @ctlr:	Pointer to spi_controller device
2353  *
2354  * Registers an spi_device for each child node of controller node which
2355  * represents a valid SPI slave.
2356  */
of_register_spi_devices(struct spi_controller * ctlr)2357 static void of_register_spi_devices(struct spi_controller *ctlr)
2358 {
2359 	struct spi_device *spi;
2360 	struct device_node *nc;
2361 
2362 	if (!ctlr->dev.of_node)
2363 		return;
2364 
2365 	for_each_available_child_of_node(ctlr->dev.of_node, nc) {
2366 		if (of_node_test_and_set_flag(nc, OF_POPULATED))
2367 			continue;
2368 		spi = of_register_spi_device(ctlr, nc);
2369 		if (IS_ERR(spi)) {
2370 			dev_warn(&ctlr->dev,
2371 				 "Failed to create SPI device for %pOF\n", nc);
2372 			of_node_clear_flag(nc, OF_POPULATED);
2373 		}
2374 	}
2375 }
2376 #else
of_register_spi_devices(struct spi_controller * ctlr)2377 static void of_register_spi_devices(struct spi_controller *ctlr) { }
2378 #endif
2379 
2380 /**
2381  * spi_new_ancillary_device() - Register ancillary SPI device
2382  * @spi:         Pointer to the main SPI device registering the ancillary device
2383  * @chip_select: Chip Select of the ancillary device
2384  *
2385  * Register an ancillary SPI device; for example some chips have a chip-select
2386  * for normal device usage and another one for setup/firmware upload.
2387  *
2388  * This may only be called from main SPI device's probe routine.
2389  *
2390  * Return: 0 on success; negative errno on failure
2391  */
spi_new_ancillary_device(struct spi_device * spi,u8 chip_select)2392 struct spi_device *spi_new_ancillary_device(struct spi_device *spi,
2393 					     u8 chip_select)
2394 {
2395 	struct spi_device *ancillary;
2396 	int rc = 0;
2397 
2398 	/* Alloc an spi_device */
2399 	ancillary = spi_alloc_device(spi->controller);
2400 	if (!ancillary) {
2401 		rc = -ENOMEM;
2402 		goto err_out;
2403 	}
2404 
2405 	strscpy(ancillary->modalias, "dummy", sizeof(ancillary->modalias));
2406 
2407 	/* Use provided chip-select for ancillary device */
2408 	ancillary->chip_select = chip_select;
2409 
2410 	/* Take over SPI mode/speed from SPI main device */
2411 	ancillary->max_speed_hz = spi->max_speed_hz;
2412 	ancillary->mode = spi->mode;
2413 
2414 	/* Register the new device */
2415 	rc = spi_add_device_locked(ancillary);
2416 	if (rc) {
2417 		dev_err(&spi->dev, "failed to register ancillary device\n");
2418 		goto err_out;
2419 	}
2420 
2421 	return ancillary;
2422 
2423 err_out:
2424 	spi_dev_put(ancillary);
2425 	return ERR_PTR(rc);
2426 }
2427 EXPORT_SYMBOL_GPL(spi_new_ancillary_device);
2428 
2429 #ifdef CONFIG_ACPI
2430 struct acpi_spi_lookup {
2431 	struct spi_controller 	*ctlr;
2432 	u32			max_speed_hz;
2433 	u32			mode;
2434 	int			irq;
2435 	u8			bits_per_word;
2436 	u8			chip_select;
2437 	int			n;
2438 	int			index;
2439 };
2440 
acpi_spi_count(struct acpi_resource * ares,void * data)2441 static int acpi_spi_count(struct acpi_resource *ares, void *data)
2442 {
2443 	struct acpi_resource_spi_serialbus *sb;
2444 	int *count = data;
2445 
2446 	if (ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
2447 		return 1;
2448 
2449 	sb = &ares->data.spi_serial_bus;
2450 	if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_SPI)
2451 		return 1;
2452 
2453 	*count = *count + 1;
2454 
2455 	return 1;
2456 }
2457 
2458 /**
2459  * acpi_spi_count_resources - Count the number of SpiSerialBus resources
2460  * @adev:	ACPI device
2461  *
2462  * Returns the number of SpiSerialBus resources in the ACPI-device's
2463  * resource-list; or a negative error code.
2464  */
acpi_spi_count_resources(struct acpi_device * adev)2465 int acpi_spi_count_resources(struct acpi_device *adev)
2466 {
2467 	LIST_HEAD(r);
2468 	int count = 0;
2469 	int ret;
2470 
2471 	ret = acpi_dev_get_resources(adev, &r, acpi_spi_count, &count);
2472 	if (ret < 0)
2473 		return ret;
2474 
2475 	acpi_dev_free_resource_list(&r);
2476 
2477 	return count;
2478 }
2479 EXPORT_SYMBOL_GPL(acpi_spi_count_resources);
2480 
acpi_spi_parse_apple_properties(struct acpi_device * dev,struct acpi_spi_lookup * lookup)2481 static void acpi_spi_parse_apple_properties(struct acpi_device *dev,
2482 					    struct acpi_spi_lookup *lookup)
2483 {
2484 	const union acpi_object *obj;
2485 
2486 	if (!x86_apple_machine)
2487 		return;
2488 
2489 	if (!acpi_dev_get_property(dev, "spiSclkPeriod", ACPI_TYPE_BUFFER, &obj)
2490 	    && obj->buffer.length >= 4)
2491 		lookup->max_speed_hz  = NSEC_PER_SEC / *(u32 *)obj->buffer.pointer;
2492 
2493 	if (!acpi_dev_get_property(dev, "spiWordSize", ACPI_TYPE_BUFFER, &obj)
2494 	    && obj->buffer.length == 8)
2495 		lookup->bits_per_word = *(u64 *)obj->buffer.pointer;
2496 
2497 	if (!acpi_dev_get_property(dev, "spiBitOrder", ACPI_TYPE_BUFFER, &obj)
2498 	    && obj->buffer.length == 8 && !*(u64 *)obj->buffer.pointer)
2499 		lookup->mode |= SPI_LSB_FIRST;
2500 
2501 	if (!acpi_dev_get_property(dev, "spiSPO", ACPI_TYPE_BUFFER, &obj)
2502 	    && obj->buffer.length == 8 &&  *(u64 *)obj->buffer.pointer)
2503 		lookup->mode |= SPI_CPOL;
2504 
2505 	if (!acpi_dev_get_property(dev, "spiSPH", ACPI_TYPE_BUFFER, &obj)
2506 	    && obj->buffer.length == 8 &&  *(u64 *)obj->buffer.pointer)
2507 		lookup->mode |= SPI_CPHA;
2508 }
2509 
2510 static struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev);
2511 
acpi_spi_add_resource(struct acpi_resource * ares,void * data)2512 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
2513 {
2514 	struct acpi_spi_lookup *lookup = data;
2515 	struct spi_controller *ctlr = lookup->ctlr;
2516 
2517 	if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
2518 		struct acpi_resource_spi_serialbus *sb;
2519 		acpi_handle parent_handle;
2520 		acpi_status status;
2521 
2522 		sb = &ares->data.spi_serial_bus;
2523 		if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
2524 
2525 			if (lookup->index != -1 && lookup->n++ != lookup->index)
2526 				return 1;
2527 
2528 			status = acpi_get_handle(NULL,
2529 						 sb->resource_source.string_ptr,
2530 						 &parent_handle);
2531 
2532 			if (ACPI_FAILURE(status))
2533 				return -ENODEV;
2534 
2535 			if (ctlr) {
2536 				if (ACPI_HANDLE(ctlr->dev.parent) != parent_handle)
2537 					return -ENODEV;
2538 			} else {
2539 				struct acpi_device *adev;
2540 
2541 				adev = acpi_fetch_acpi_dev(parent_handle);
2542 				if (!adev)
2543 					return -ENODEV;
2544 
2545 				ctlr = acpi_spi_find_controller_by_adev(adev);
2546 				if (!ctlr)
2547 					return -EPROBE_DEFER;
2548 
2549 				lookup->ctlr = ctlr;
2550 			}
2551 
2552 			/*
2553 			 * ACPI DeviceSelection numbering is handled by the
2554 			 * host controller driver in Windows and can vary
2555 			 * from driver to driver. In Linux we always expect
2556 			 * 0 .. max - 1 so we need to ask the driver to
2557 			 * translate between the two schemes.
2558 			 */
2559 			if (ctlr->fw_translate_cs) {
2560 				int cs = ctlr->fw_translate_cs(ctlr,
2561 						sb->device_selection);
2562 				if (cs < 0)
2563 					return cs;
2564 				lookup->chip_select = cs;
2565 			} else {
2566 				lookup->chip_select = sb->device_selection;
2567 			}
2568 
2569 			lookup->max_speed_hz = sb->connection_speed;
2570 			lookup->bits_per_word = sb->data_bit_length;
2571 
2572 			if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
2573 				lookup->mode |= SPI_CPHA;
2574 			if (sb->clock_polarity == ACPI_SPI_START_HIGH)
2575 				lookup->mode |= SPI_CPOL;
2576 			if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
2577 				lookup->mode |= SPI_CS_HIGH;
2578 		}
2579 	} else if (lookup->irq < 0) {
2580 		struct resource r;
2581 
2582 		if (acpi_dev_resource_interrupt(ares, 0, &r))
2583 			lookup->irq = r.start;
2584 	}
2585 
2586 	/* Always tell the ACPI core to skip this resource */
2587 	return 1;
2588 }
2589 
2590 /**
2591  * acpi_spi_device_alloc - Allocate a spi device, and fill it in with ACPI information
2592  * @ctlr: controller to which the spi device belongs
2593  * @adev: ACPI Device for the spi device
2594  * @index: Index of the spi resource inside the ACPI Node
2595  *
2596  * This should be used to allocate a new spi device from and ACPI Node.
2597  * The caller is responsible for calling spi_add_device to register the spi device.
2598  *
2599  * If ctlr is set to NULL, the Controller for the spi device will be looked up
2600  * using the resource.
2601  * If index is set to -1, index is not used.
2602  * Note: If index is -1, ctlr must be set.
2603  *
2604  * Return: a pointer to the new device, or ERR_PTR on error.
2605  */
acpi_spi_device_alloc(struct spi_controller * ctlr,struct acpi_device * adev,int index)2606 struct spi_device *acpi_spi_device_alloc(struct spi_controller *ctlr,
2607 					 struct acpi_device *adev,
2608 					 int index)
2609 {
2610 	acpi_handle parent_handle = NULL;
2611 	struct list_head resource_list;
2612 	struct acpi_spi_lookup lookup = {};
2613 	struct spi_device *spi;
2614 	int ret;
2615 
2616 	if (!ctlr && index == -1)
2617 		return ERR_PTR(-EINVAL);
2618 
2619 	lookup.ctlr		= ctlr;
2620 	lookup.irq		= -1;
2621 	lookup.index		= index;
2622 	lookup.n		= 0;
2623 
2624 	INIT_LIST_HEAD(&resource_list);
2625 	ret = acpi_dev_get_resources(adev, &resource_list,
2626 				     acpi_spi_add_resource, &lookup);
2627 	acpi_dev_free_resource_list(&resource_list);
2628 
2629 	if (ret < 0)
2630 		/* Found SPI in _CRS but it points to another controller */
2631 		return ERR_PTR(ret);
2632 
2633 	if (!lookup.max_speed_hz &&
2634 	    ACPI_SUCCESS(acpi_get_parent(adev->handle, &parent_handle)) &&
2635 	    ACPI_HANDLE(lookup.ctlr->dev.parent) == parent_handle) {
2636 		/* Apple does not use _CRS but nested devices for SPI slaves */
2637 		acpi_spi_parse_apple_properties(adev, &lookup);
2638 	}
2639 
2640 	if (!lookup.max_speed_hz)
2641 		return ERR_PTR(-ENODEV);
2642 
2643 	spi = spi_alloc_device(lookup.ctlr);
2644 	if (!spi) {
2645 		dev_err(&lookup.ctlr->dev, "failed to allocate SPI device for %s\n",
2646 			dev_name(&adev->dev));
2647 		return ERR_PTR(-ENOMEM);
2648 	}
2649 
2650 	ACPI_COMPANION_SET(&spi->dev, adev);
2651 	spi->max_speed_hz	= lookup.max_speed_hz;
2652 	spi->mode		|= lookup.mode;
2653 	spi->irq		= lookup.irq;
2654 	spi->bits_per_word	= lookup.bits_per_word;
2655 	spi->chip_select	= lookup.chip_select;
2656 
2657 	return spi;
2658 }
2659 EXPORT_SYMBOL_GPL(acpi_spi_device_alloc);
2660 
acpi_register_spi_device(struct spi_controller * ctlr,struct acpi_device * adev)2661 static acpi_status acpi_register_spi_device(struct spi_controller *ctlr,
2662 					    struct acpi_device *adev)
2663 {
2664 	struct spi_device *spi;
2665 
2666 	if (acpi_bus_get_status(adev) || !adev->status.present ||
2667 	    acpi_device_enumerated(adev))
2668 		return AE_OK;
2669 
2670 	spi = acpi_spi_device_alloc(ctlr, adev, -1);
2671 	if (IS_ERR(spi)) {
2672 		if (PTR_ERR(spi) == -ENOMEM)
2673 			return AE_NO_MEMORY;
2674 		else
2675 			return AE_OK;
2676 	}
2677 
2678 	acpi_set_modalias(adev, acpi_device_hid(adev), spi->modalias,
2679 			  sizeof(spi->modalias));
2680 
2681 	if (spi->irq < 0)
2682 		spi->irq = acpi_dev_gpio_irq_get(adev, 0);
2683 
2684 	acpi_device_set_enumerated(adev);
2685 
2686 	adev->power.flags.ignore_parent = true;
2687 	if (spi_add_device(spi)) {
2688 		adev->power.flags.ignore_parent = false;
2689 		dev_err(&ctlr->dev, "failed to add SPI device %s from ACPI\n",
2690 			dev_name(&adev->dev));
2691 		spi_dev_put(spi);
2692 	}
2693 
2694 	return AE_OK;
2695 }
2696 
acpi_spi_add_device(acpi_handle handle,u32 level,void * data,void ** return_value)2697 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
2698 				       void *data, void **return_value)
2699 {
2700 	struct acpi_device *adev = acpi_fetch_acpi_dev(handle);
2701 	struct spi_controller *ctlr = data;
2702 
2703 	if (!adev)
2704 		return AE_OK;
2705 
2706 	return acpi_register_spi_device(ctlr, adev);
2707 }
2708 
2709 #define SPI_ACPI_ENUMERATE_MAX_DEPTH		32
2710 
acpi_register_spi_devices(struct spi_controller * ctlr)2711 static void acpi_register_spi_devices(struct spi_controller *ctlr)
2712 {
2713 	acpi_status status;
2714 	acpi_handle handle;
2715 
2716 	handle = ACPI_HANDLE(ctlr->dev.parent);
2717 	if (!handle)
2718 		return;
2719 
2720 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
2721 				     SPI_ACPI_ENUMERATE_MAX_DEPTH,
2722 				     acpi_spi_add_device, NULL, ctlr, NULL);
2723 	if (ACPI_FAILURE(status))
2724 		dev_warn(&ctlr->dev, "failed to enumerate SPI slaves\n");
2725 }
2726 #else
acpi_register_spi_devices(struct spi_controller * ctlr)2727 static inline void acpi_register_spi_devices(struct spi_controller *ctlr) {}
2728 #endif /* CONFIG_ACPI */
2729 
spi_controller_release(struct device * dev)2730 static void spi_controller_release(struct device *dev)
2731 {
2732 	struct spi_controller *ctlr;
2733 
2734 	ctlr = container_of(dev, struct spi_controller, dev);
2735 	kfree(ctlr);
2736 }
2737 
2738 static struct class spi_master_class = {
2739 	.name		= "spi_master",
2740 	.owner		= THIS_MODULE,
2741 	.dev_release	= spi_controller_release,
2742 	.dev_groups	= spi_master_groups,
2743 };
2744 
2745 #ifdef CONFIG_SPI_SLAVE
2746 /**
2747  * spi_slave_abort - abort the ongoing transfer request on an SPI slave
2748  *		     controller
2749  * @spi: device used for the current transfer
2750  */
spi_slave_abort(struct spi_device * spi)2751 int spi_slave_abort(struct spi_device *spi)
2752 {
2753 	struct spi_controller *ctlr = spi->controller;
2754 
2755 	if (spi_controller_is_slave(ctlr) && ctlr->slave_abort)
2756 		return ctlr->slave_abort(ctlr);
2757 
2758 	return -ENOTSUPP;
2759 }
2760 EXPORT_SYMBOL_GPL(spi_slave_abort);
2761 
slave_show(struct device * dev,struct device_attribute * attr,char * buf)2762 static ssize_t slave_show(struct device *dev, struct device_attribute *attr,
2763 			  char *buf)
2764 {
2765 	struct spi_controller *ctlr = container_of(dev, struct spi_controller,
2766 						   dev);
2767 	struct device *child;
2768 
2769 	child = device_find_any_child(&ctlr->dev);
2770 	return sprintf(buf, "%s\n",
2771 		       child ? to_spi_device(child)->modalias : NULL);
2772 }
2773 
slave_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)2774 static ssize_t slave_store(struct device *dev, struct device_attribute *attr,
2775 			   const char *buf, size_t count)
2776 {
2777 	struct spi_controller *ctlr = container_of(dev, struct spi_controller,
2778 						   dev);
2779 	struct spi_device *spi;
2780 	struct device *child;
2781 	char name[32];
2782 	int rc;
2783 
2784 	rc = sscanf(buf, "%31s", name);
2785 	if (rc != 1 || !name[0])
2786 		return -EINVAL;
2787 
2788 	child = device_find_any_child(&ctlr->dev);
2789 	if (child) {
2790 		/* Remove registered slave */
2791 		device_unregister(child);
2792 		put_device(child);
2793 	}
2794 
2795 	if (strcmp(name, "(null)")) {
2796 		/* Register new slave */
2797 		spi = spi_alloc_device(ctlr);
2798 		if (!spi)
2799 			return -ENOMEM;
2800 
2801 		strscpy(spi->modalias, name, sizeof(spi->modalias));
2802 
2803 		rc = spi_add_device(spi);
2804 		if (rc) {
2805 			spi_dev_put(spi);
2806 			return rc;
2807 		}
2808 	}
2809 
2810 	return count;
2811 }
2812 
2813 static DEVICE_ATTR_RW(slave);
2814 
2815 static struct attribute *spi_slave_attrs[] = {
2816 	&dev_attr_slave.attr,
2817 	NULL,
2818 };
2819 
2820 static const struct attribute_group spi_slave_group = {
2821 	.attrs = spi_slave_attrs,
2822 };
2823 
2824 static const struct attribute_group *spi_slave_groups[] = {
2825 	&spi_controller_statistics_group,
2826 	&spi_slave_group,
2827 	NULL,
2828 };
2829 
2830 static struct class spi_slave_class = {
2831 	.name		= "spi_slave",
2832 	.owner		= THIS_MODULE,
2833 	.dev_release	= spi_controller_release,
2834 	.dev_groups	= spi_slave_groups,
2835 };
2836 #else
2837 extern struct class spi_slave_class;	/* dummy */
2838 #endif
2839 
2840 /**
2841  * __spi_alloc_controller - allocate an SPI master or slave controller
2842  * @dev: the controller, possibly using the platform_bus
2843  * @size: how much zeroed driver-private data to allocate; the pointer to this
2844  *	memory is in the driver_data field of the returned device, accessible
2845  *	with spi_controller_get_devdata(); the memory is cacheline aligned;
2846  *	drivers granting DMA access to portions of their private data need to
2847  *	round up @size using ALIGN(size, dma_get_cache_alignment()).
2848  * @slave: flag indicating whether to allocate an SPI master (false) or SPI
2849  *	slave (true) controller
2850  * Context: can sleep
2851  *
2852  * This call is used only by SPI controller drivers, which are the
2853  * only ones directly touching chip registers.  It's how they allocate
2854  * an spi_controller structure, prior to calling spi_register_controller().
2855  *
2856  * This must be called from context that can sleep.
2857  *
2858  * The caller is responsible for assigning the bus number and initializing the
2859  * controller's methods before calling spi_register_controller(); and (after
2860  * errors adding the device) calling spi_controller_put() to prevent a memory
2861  * leak.
2862  *
2863  * Return: the SPI controller structure on success, else NULL.
2864  */
__spi_alloc_controller(struct device * dev,unsigned int size,bool slave)2865 struct spi_controller *__spi_alloc_controller(struct device *dev,
2866 					      unsigned int size, bool slave)
2867 {
2868 	struct spi_controller	*ctlr;
2869 	size_t ctlr_size = ALIGN(sizeof(*ctlr), dma_get_cache_alignment());
2870 
2871 	if (!dev)
2872 		return NULL;
2873 
2874 	ctlr = kzalloc(size + ctlr_size, GFP_KERNEL);
2875 	if (!ctlr)
2876 		return NULL;
2877 
2878 	device_initialize(&ctlr->dev);
2879 	INIT_LIST_HEAD(&ctlr->queue);
2880 	spin_lock_init(&ctlr->queue_lock);
2881 	spin_lock_init(&ctlr->bus_lock_spinlock);
2882 	mutex_init(&ctlr->bus_lock_mutex);
2883 	mutex_init(&ctlr->io_mutex);
2884 	mutex_init(&ctlr->add_lock);
2885 	ctlr->bus_num = -1;
2886 	ctlr->num_chipselect = 1;
2887 	ctlr->slave = slave;
2888 	if (IS_ENABLED(CONFIG_SPI_SLAVE) && slave)
2889 		ctlr->dev.class = &spi_slave_class;
2890 	else
2891 		ctlr->dev.class = &spi_master_class;
2892 	ctlr->dev.parent = dev;
2893 	pm_suspend_ignore_children(&ctlr->dev, true);
2894 	spi_controller_set_devdata(ctlr, (void *)ctlr + ctlr_size);
2895 
2896 	return ctlr;
2897 }
2898 EXPORT_SYMBOL_GPL(__spi_alloc_controller);
2899 
devm_spi_release_controller(struct device * dev,void * ctlr)2900 static void devm_spi_release_controller(struct device *dev, void *ctlr)
2901 {
2902 	spi_controller_put(*(struct spi_controller **)ctlr);
2903 }
2904 
2905 /**
2906  * __devm_spi_alloc_controller - resource-managed __spi_alloc_controller()
2907  * @dev: physical device of SPI controller
2908  * @size: how much zeroed driver-private data to allocate
2909  * @slave: whether to allocate an SPI master (false) or SPI slave (true)
2910  * Context: can sleep
2911  *
2912  * Allocate an SPI controller and automatically release a reference on it
2913  * when @dev is unbound from its driver.  Drivers are thus relieved from
2914  * having to call spi_controller_put().
2915  *
2916  * The arguments to this function are identical to __spi_alloc_controller().
2917  *
2918  * Return: the SPI controller structure on success, else NULL.
2919  */
__devm_spi_alloc_controller(struct device * dev,unsigned int size,bool slave)2920 struct spi_controller *__devm_spi_alloc_controller(struct device *dev,
2921 						   unsigned int size,
2922 						   bool slave)
2923 {
2924 	struct spi_controller **ptr, *ctlr;
2925 
2926 	ptr = devres_alloc(devm_spi_release_controller, sizeof(*ptr),
2927 			   GFP_KERNEL);
2928 	if (!ptr)
2929 		return NULL;
2930 
2931 	ctlr = __spi_alloc_controller(dev, size, slave);
2932 	if (ctlr) {
2933 		ctlr->devm_allocated = true;
2934 		*ptr = ctlr;
2935 		devres_add(dev, ptr);
2936 	} else {
2937 		devres_free(ptr);
2938 	}
2939 
2940 	return ctlr;
2941 }
2942 EXPORT_SYMBOL_GPL(__devm_spi_alloc_controller);
2943 
2944 /**
2945  * spi_get_gpio_descs() - grab chip select GPIOs for the master
2946  * @ctlr: The SPI master to grab GPIO descriptors for
2947  */
spi_get_gpio_descs(struct spi_controller * ctlr)2948 static int spi_get_gpio_descs(struct spi_controller *ctlr)
2949 {
2950 	int nb, i;
2951 	struct gpio_desc **cs;
2952 	struct device *dev = &ctlr->dev;
2953 	unsigned long native_cs_mask = 0;
2954 	unsigned int num_cs_gpios = 0;
2955 
2956 	nb = gpiod_count(dev, "cs");
2957 	if (nb < 0) {
2958 		/* No GPIOs at all is fine, else return the error */
2959 		if (nb == -ENOENT)
2960 			return 0;
2961 		return nb;
2962 	}
2963 
2964 	ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
2965 
2966 	cs = devm_kcalloc(dev, ctlr->num_chipselect, sizeof(*cs),
2967 			  GFP_KERNEL);
2968 	if (!cs)
2969 		return -ENOMEM;
2970 	ctlr->cs_gpiods = cs;
2971 
2972 	for (i = 0; i < nb; i++) {
2973 		/*
2974 		 * Most chipselects are active low, the inverted
2975 		 * semantics are handled by special quirks in gpiolib,
2976 		 * so initializing them GPIOD_OUT_LOW here means
2977 		 * "unasserted", in most cases this will drive the physical
2978 		 * line high.
2979 		 */
2980 		cs[i] = devm_gpiod_get_index_optional(dev, "cs", i,
2981 						      GPIOD_OUT_LOW);
2982 		if (IS_ERR(cs[i]))
2983 			return PTR_ERR(cs[i]);
2984 
2985 		if (cs[i]) {
2986 			/*
2987 			 * If we find a CS GPIO, name it after the device and
2988 			 * chip select line.
2989 			 */
2990 			char *gpioname;
2991 
2992 			gpioname = devm_kasprintf(dev, GFP_KERNEL, "%s CS%d",
2993 						  dev_name(dev), i);
2994 			if (!gpioname)
2995 				return -ENOMEM;
2996 			gpiod_set_consumer_name(cs[i], gpioname);
2997 			num_cs_gpios++;
2998 			continue;
2999 		}
3000 
3001 		if (ctlr->max_native_cs && i >= ctlr->max_native_cs) {
3002 			dev_err(dev, "Invalid native chip select %d\n", i);
3003 			return -EINVAL;
3004 		}
3005 		native_cs_mask |= BIT(i);
3006 	}
3007 
3008 	ctlr->unused_native_cs = ffs(~native_cs_mask) - 1;
3009 
3010 	if ((ctlr->flags & SPI_MASTER_GPIO_SS) && num_cs_gpios &&
3011 	    ctlr->max_native_cs && ctlr->unused_native_cs >= ctlr->max_native_cs) {
3012 		dev_err(dev, "No unused native chip select available\n");
3013 		return -EINVAL;
3014 	}
3015 
3016 	return 0;
3017 }
3018 
spi_controller_check_ops(struct spi_controller * ctlr)3019 static int spi_controller_check_ops(struct spi_controller *ctlr)
3020 {
3021 	/*
3022 	 * The controller may implement only the high-level SPI-memory like
3023 	 * operations if it does not support regular SPI transfers, and this is
3024 	 * valid use case.
3025 	 * If ->mem_ops is NULL, we request that at least one of the
3026 	 * ->transfer_xxx() method be implemented.
3027 	 */
3028 	if (ctlr->mem_ops) {
3029 		if (!ctlr->mem_ops->exec_op)
3030 			return -EINVAL;
3031 	} else if (!ctlr->transfer && !ctlr->transfer_one &&
3032 		   !ctlr->transfer_one_message) {
3033 		return -EINVAL;
3034 	}
3035 
3036 	return 0;
3037 }
3038 
3039 /**
3040  * spi_register_controller - register SPI master or slave controller
3041  * @ctlr: initialized master, originally from spi_alloc_master() or
3042  *	spi_alloc_slave()
3043  * Context: can sleep
3044  *
3045  * SPI controllers connect to their drivers using some non-SPI bus,
3046  * such as the platform bus.  The final stage of probe() in that code
3047  * includes calling spi_register_controller() to hook up to this SPI bus glue.
3048  *
3049  * SPI controllers use board specific (often SOC specific) bus numbers,
3050  * and board-specific addressing for SPI devices combines those numbers
3051  * with chip select numbers.  Since SPI does not directly support dynamic
3052  * device identification, boards need configuration tables telling which
3053  * chip is at which address.
3054  *
3055  * This must be called from context that can sleep.  It returns zero on
3056  * success, else a negative error code (dropping the controller's refcount).
3057  * After a successful return, the caller is responsible for calling
3058  * spi_unregister_controller().
3059  *
3060  * Return: zero on success, else a negative error code.
3061  */
spi_register_controller(struct spi_controller * ctlr)3062 int spi_register_controller(struct spi_controller *ctlr)
3063 {
3064 	struct device		*dev = ctlr->dev.parent;
3065 	struct boardinfo	*bi;
3066 	int			status;
3067 	int			id, first_dynamic;
3068 
3069 	if (!dev)
3070 		return -ENODEV;
3071 
3072 	/*
3073 	 * Make sure all necessary hooks are implemented before registering
3074 	 * the SPI controller.
3075 	 */
3076 	status = spi_controller_check_ops(ctlr);
3077 	if (status)
3078 		return status;
3079 
3080 	if (ctlr->bus_num >= 0) {
3081 		/* Devices with a fixed bus num must check-in with the num */
3082 		mutex_lock(&board_lock);
3083 		id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
3084 			ctlr->bus_num + 1, GFP_KERNEL);
3085 		mutex_unlock(&board_lock);
3086 		if (WARN(id < 0, "couldn't get idr"))
3087 			return id == -ENOSPC ? -EBUSY : id;
3088 		ctlr->bus_num = id;
3089 	} else if (ctlr->dev.of_node) {
3090 		/* Allocate dynamic bus number using Linux idr */
3091 		id = of_alias_get_id(ctlr->dev.of_node, "spi");
3092 		if (id >= 0) {
3093 			ctlr->bus_num = id;
3094 			mutex_lock(&board_lock);
3095 			id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
3096 				       ctlr->bus_num + 1, GFP_KERNEL);
3097 			mutex_unlock(&board_lock);
3098 			if (WARN(id < 0, "couldn't get idr"))
3099 				return id == -ENOSPC ? -EBUSY : id;
3100 		}
3101 	}
3102 	if (ctlr->bus_num < 0) {
3103 		first_dynamic = of_alias_get_highest_id("spi");
3104 		if (first_dynamic < 0)
3105 			first_dynamic = 0;
3106 		else
3107 			first_dynamic++;
3108 
3109 		mutex_lock(&board_lock);
3110 		id = idr_alloc(&spi_master_idr, ctlr, first_dynamic,
3111 			       0, GFP_KERNEL);
3112 		mutex_unlock(&board_lock);
3113 		if (WARN(id < 0, "couldn't get idr"))
3114 			return id;
3115 		ctlr->bus_num = id;
3116 	}
3117 	ctlr->bus_lock_flag = 0;
3118 	init_completion(&ctlr->xfer_completion);
3119 	init_completion(&ctlr->cur_msg_completion);
3120 	if (!ctlr->max_dma_len)
3121 		ctlr->max_dma_len = INT_MAX;
3122 
3123 	/*
3124 	 * Register the device, then userspace will see it.
3125 	 * Registration fails if the bus ID is in use.
3126 	 */
3127 	dev_set_name(&ctlr->dev, "spi%u", ctlr->bus_num);
3128 
3129 	if (!spi_controller_is_slave(ctlr) && ctlr->use_gpio_descriptors) {
3130 		status = spi_get_gpio_descs(ctlr);
3131 		if (status)
3132 			goto free_bus_id;
3133 		/*
3134 		 * A controller using GPIO descriptors always
3135 		 * supports SPI_CS_HIGH if need be.
3136 		 */
3137 		ctlr->mode_bits |= SPI_CS_HIGH;
3138 	}
3139 
3140 	/*
3141 	 * Even if it's just one always-selected device, there must
3142 	 * be at least one chipselect.
3143 	 */
3144 	if (!ctlr->num_chipselect) {
3145 		status = -EINVAL;
3146 		goto free_bus_id;
3147 	}
3148 
3149 	/* Setting last_cs to -1 means no chip selected */
3150 	ctlr->last_cs = -1;
3151 
3152 	status = device_add(&ctlr->dev);
3153 	if (status < 0)
3154 		goto free_bus_id;
3155 	dev_dbg(dev, "registered %s %s\n",
3156 			spi_controller_is_slave(ctlr) ? "slave" : "master",
3157 			dev_name(&ctlr->dev));
3158 
3159 	/*
3160 	 * If we're using a queued driver, start the queue. Note that we don't
3161 	 * need the queueing logic if the driver is only supporting high-level
3162 	 * memory operations.
3163 	 */
3164 	if (ctlr->transfer) {
3165 		dev_info(dev, "controller is unqueued, this is deprecated\n");
3166 	} else if (ctlr->transfer_one || ctlr->transfer_one_message) {
3167 		status = spi_controller_initialize_queue(ctlr);
3168 		if (status) {
3169 			device_del(&ctlr->dev);
3170 			goto free_bus_id;
3171 		}
3172 	}
3173 	/* Add statistics */
3174 	ctlr->pcpu_statistics = spi_alloc_pcpu_stats(dev);
3175 	if (!ctlr->pcpu_statistics) {
3176 		dev_err(dev, "Error allocating per-cpu statistics\n");
3177 		status = -ENOMEM;
3178 		goto destroy_queue;
3179 	}
3180 
3181 	mutex_lock(&board_lock);
3182 	list_add_tail(&ctlr->list, &spi_controller_list);
3183 	list_for_each_entry(bi, &board_list, list)
3184 		spi_match_controller_to_boardinfo(ctlr, &bi->board_info);
3185 	mutex_unlock(&board_lock);
3186 
3187 	/* Register devices from the device tree and ACPI */
3188 	of_register_spi_devices(ctlr);
3189 	acpi_register_spi_devices(ctlr);
3190 	return status;
3191 
3192 destroy_queue:
3193 	spi_destroy_queue(ctlr);
3194 free_bus_id:
3195 	mutex_lock(&board_lock);
3196 	idr_remove(&spi_master_idr, ctlr->bus_num);
3197 	mutex_unlock(&board_lock);
3198 	return status;
3199 }
3200 EXPORT_SYMBOL_GPL(spi_register_controller);
3201 
devm_spi_unregister(struct device * dev,void * res)3202 static void devm_spi_unregister(struct device *dev, void *res)
3203 {
3204 	spi_unregister_controller(*(struct spi_controller **)res);
3205 }
3206 
3207 /**
3208  * devm_spi_register_controller - register managed SPI master or slave
3209  *	controller
3210  * @dev:    device managing SPI controller
3211  * @ctlr: initialized controller, originally from spi_alloc_master() or
3212  *	spi_alloc_slave()
3213  * Context: can sleep
3214  *
3215  * Register a SPI device as with spi_register_controller() which will
3216  * automatically be unregistered and freed.
3217  *
3218  * Return: zero on success, else a negative error code.
3219  */
devm_spi_register_controller(struct device * dev,struct spi_controller * ctlr)3220 int devm_spi_register_controller(struct device *dev,
3221 				 struct spi_controller *ctlr)
3222 {
3223 	struct spi_controller **ptr;
3224 	int ret;
3225 
3226 	ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
3227 	if (!ptr)
3228 		return -ENOMEM;
3229 
3230 	ret = spi_register_controller(ctlr);
3231 	if (!ret) {
3232 		*ptr = ctlr;
3233 		devres_add(dev, ptr);
3234 	} else {
3235 		devres_free(ptr);
3236 	}
3237 
3238 	return ret;
3239 }
3240 EXPORT_SYMBOL_GPL(devm_spi_register_controller);
3241 
__unregister(struct device * dev,void * null)3242 static int __unregister(struct device *dev, void *null)
3243 {
3244 	spi_unregister_device(to_spi_device(dev));
3245 	return 0;
3246 }
3247 
3248 /**
3249  * spi_unregister_controller - unregister SPI master or slave controller
3250  * @ctlr: the controller being unregistered
3251  * Context: can sleep
3252  *
3253  * This call is used only by SPI controller drivers, which are the
3254  * only ones directly touching chip registers.
3255  *
3256  * This must be called from context that can sleep.
3257  *
3258  * Note that this function also drops a reference to the controller.
3259  */
spi_unregister_controller(struct spi_controller * ctlr)3260 void spi_unregister_controller(struct spi_controller *ctlr)
3261 {
3262 	struct spi_controller *found;
3263 	int id = ctlr->bus_num;
3264 
3265 	/* Prevent addition of new devices, unregister existing ones */
3266 	if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
3267 		mutex_lock(&ctlr->add_lock);
3268 
3269 	device_for_each_child(&ctlr->dev, NULL, __unregister);
3270 
3271 	/* First make sure that this controller was ever added */
3272 	mutex_lock(&board_lock);
3273 	found = idr_find(&spi_master_idr, id);
3274 	mutex_unlock(&board_lock);
3275 	if (ctlr->queued) {
3276 		if (spi_destroy_queue(ctlr))
3277 			dev_err(&ctlr->dev, "queue remove failed\n");
3278 	}
3279 	mutex_lock(&board_lock);
3280 	list_del(&ctlr->list);
3281 	mutex_unlock(&board_lock);
3282 
3283 	device_del(&ctlr->dev);
3284 
3285 	/* Free bus id */
3286 	mutex_lock(&board_lock);
3287 	if (found == ctlr)
3288 		idr_remove(&spi_master_idr, id);
3289 	mutex_unlock(&board_lock);
3290 
3291 	if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
3292 		mutex_unlock(&ctlr->add_lock);
3293 
3294 	/* Release the last reference on the controller if its driver
3295 	 * has not yet been converted to devm_spi_alloc_master/slave().
3296 	 */
3297 	if (!ctlr->devm_allocated)
3298 		put_device(&ctlr->dev);
3299 }
3300 EXPORT_SYMBOL_GPL(spi_unregister_controller);
3301 
spi_controller_suspend(struct spi_controller * ctlr)3302 int spi_controller_suspend(struct spi_controller *ctlr)
3303 {
3304 	int ret;
3305 
3306 	/* Basically no-ops for non-queued controllers */
3307 	if (!ctlr->queued)
3308 		return 0;
3309 
3310 	ret = spi_stop_queue(ctlr);
3311 	if (ret)
3312 		dev_err(&ctlr->dev, "queue stop failed\n");
3313 
3314 	return ret;
3315 }
3316 EXPORT_SYMBOL_GPL(spi_controller_suspend);
3317 
spi_controller_resume(struct spi_controller * ctlr)3318 int spi_controller_resume(struct spi_controller *ctlr)
3319 {
3320 	int ret;
3321 
3322 	if (!ctlr->queued)
3323 		return 0;
3324 
3325 	ret = spi_start_queue(ctlr);
3326 	if (ret)
3327 		dev_err(&ctlr->dev, "queue restart failed\n");
3328 
3329 	return ret;
3330 }
3331 EXPORT_SYMBOL_GPL(spi_controller_resume);
3332 
3333 /*-------------------------------------------------------------------------*/
3334 
3335 /* Core methods for spi_message alterations */
3336 
__spi_replace_transfers_release(struct spi_controller * ctlr,struct spi_message * msg,void * res)3337 static void __spi_replace_transfers_release(struct spi_controller *ctlr,
3338 					    struct spi_message *msg,
3339 					    void *res)
3340 {
3341 	struct spi_replaced_transfers *rxfer = res;
3342 	size_t i;
3343 
3344 	/* Call extra callback if requested */
3345 	if (rxfer->release)
3346 		rxfer->release(ctlr, msg, res);
3347 
3348 	/* Insert replaced transfers back into the message */
3349 	list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
3350 
3351 	/* Remove the formerly inserted entries */
3352 	for (i = 0; i < rxfer->inserted; i++)
3353 		list_del(&rxfer->inserted_transfers[i].transfer_list);
3354 }
3355 
3356 /**
3357  * spi_replace_transfers - replace transfers with several transfers
3358  *                         and register change with spi_message.resources
3359  * @msg:           the spi_message we work upon
3360  * @xfer_first:    the first spi_transfer we want to replace
3361  * @remove:        number of transfers to remove
3362  * @insert:        the number of transfers we want to insert instead
3363  * @release:       extra release code necessary in some circumstances
3364  * @extradatasize: extra data to allocate (with alignment guarantees
3365  *                 of struct @spi_transfer)
3366  * @gfp:           gfp flags
3367  *
3368  * Returns: pointer to @spi_replaced_transfers,
3369  *          PTR_ERR(...) in case of errors.
3370  */
spi_replace_transfers(struct spi_message * msg,struct spi_transfer * xfer_first,size_t remove,size_t insert,spi_replaced_release_t release,size_t extradatasize,gfp_t gfp)3371 static struct spi_replaced_transfers *spi_replace_transfers(
3372 	struct spi_message *msg,
3373 	struct spi_transfer *xfer_first,
3374 	size_t remove,
3375 	size_t insert,
3376 	spi_replaced_release_t release,
3377 	size_t extradatasize,
3378 	gfp_t gfp)
3379 {
3380 	struct spi_replaced_transfers *rxfer;
3381 	struct spi_transfer *xfer;
3382 	size_t i;
3383 
3384 	/* Allocate the structure using spi_res */
3385 	rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
3386 			      struct_size(rxfer, inserted_transfers, insert)
3387 			      + extradatasize,
3388 			      gfp);
3389 	if (!rxfer)
3390 		return ERR_PTR(-ENOMEM);
3391 
3392 	/* The release code to invoke before running the generic release */
3393 	rxfer->release = release;
3394 
3395 	/* Assign extradata */
3396 	if (extradatasize)
3397 		rxfer->extradata =
3398 			&rxfer->inserted_transfers[insert];
3399 
3400 	/* Init the replaced_transfers list */
3401 	INIT_LIST_HEAD(&rxfer->replaced_transfers);
3402 
3403 	/*
3404 	 * Assign the list_entry after which we should reinsert
3405 	 * the @replaced_transfers - it may be spi_message.messages!
3406 	 */
3407 	rxfer->replaced_after = xfer_first->transfer_list.prev;
3408 
3409 	/* Remove the requested number of transfers */
3410 	for (i = 0; i < remove; i++) {
3411 		/*
3412 		 * If the entry after replaced_after it is msg->transfers
3413 		 * then we have been requested to remove more transfers
3414 		 * than are in the list.
3415 		 */
3416 		if (rxfer->replaced_after->next == &msg->transfers) {
3417 			dev_err(&msg->spi->dev,
3418 				"requested to remove more spi_transfers than are available\n");
3419 			/* Insert replaced transfers back into the message */
3420 			list_splice(&rxfer->replaced_transfers,
3421 				    rxfer->replaced_after);
3422 
3423 			/* Free the spi_replace_transfer structure... */
3424 			spi_res_free(rxfer);
3425 
3426 			/* ...and return with an error */
3427 			return ERR_PTR(-EINVAL);
3428 		}
3429 
3430 		/*
3431 		 * Remove the entry after replaced_after from list of
3432 		 * transfers and add it to list of replaced_transfers.
3433 		 */
3434 		list_move_tail(rxfer->replaced_after->next,
3435 			       &rxfer->replaced_transfers);
3436 	}
3437 
3438 	/*
3439 	 * Create copy of the given xfer with identical settings
3440 	 * based on the first transfer to get removed.
3441 	 */
3442 	for (i = 0; i < insert; i++) {
3443 		/* We need to run in reverse order */
3444 		xfer = &rxfer->inserted_transfers[insert - 1 - i];
3445 
3446 		/* Copy all spi_transfer data */
3447 		memcpy(xfer, xfer_first, sizeof(*xfer));
3448 
3449 		/* Add to list */
3450 		list_add(&xfer->transfer_list, rxfer->replaced_after);
3451 
3452 		/* Clear cs_change and delay for all but the last */
3453 		if (i) {
3454 			xfer->cs_change = false;
3455 			xfer->delay.value = 0;
3456 		}
3457 	}
3458 
3459 	/* Set up inserted... */
3460 	rxfer->inserted = insert;
3461 
3462 	/* ...and register it with spi_res/spi_message */
3463 	spi_res_add(msg, rxfer);
3464 
3465 	return rxfer;
3466 }
3467 
__spi_split_transfer_maxsize(struct spi_controller * ctlr,struct spi_message * msg,struct spi_transfer ** xferp,size_t maxsize,gfp_t gfp)3468 static int __spi_split_transfer_maxsize(struct spi_controller *ctlr,
3469 					struct spi_message *msg,
3470 					struct spi_transfer **xferp,
3471 					size_t maxsize,
3472 					gfp_t gfp)
3473 {
3474 	struct spi_transfer *xfer = *xferp, *xfers;
3475 	struct spi_replaced_transfers *srt;
3476 	size_t offset;
3477 	size_t count, i;
3478 
3479 	/* Calculate how many we have to replace */
3480 	count = DIV_ROUND_UP(xfer->len, maxsize);
3481 
3482 	/* Create replacement */
3483 	srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, gfp);
3484 	if (IS_ERR(srt))
3485 		return PTR_ERR(srt);
3486 	xfers = srt->inserted_transfers;
3487 
3488 	/*
3489 	 * Now handle each of those newly inserted spi_transfers.
3490 	 * Note that the replacements spi_transfers all are preset
3491 	 * to the same values as *xferp, so tx_buf, rx_buf and len
3492 	 * are all identical (as well as most others)
3493 	 * so we just have to fix up len and the pointers.
3494 	 *
3495 	 * This also includes support for the depreciated
3496 	 * spi_message.is_dma_mapped interface.
3497 	 */
3498 
3499 	/*
3500 	 * The first transfer just needs the length modified, so we
3501 	 * run it outside the loop.
3502 	 */
3503 	xfers[0].len = min_t(size_t, maxsize, xfer[0].len);
3504 
3505 	/* All the others need rx_buf/tx_buf also set */
3506 	for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) {
3507 		/* Update rx_buf, tx_buf and dma */
3508 		if (xfers[i].rx_buf)
3509 			xfers[i].rx_buf += offset;
3510 		if (xfers[i].rx_dma)
3511 			xfers[i].rx_dma += offset;
3512 		if (xfers[i].tx_buf)
3513 			xfers[i].tx_buf += offset;
3514 		if (xfers[i].tx_dma)
3515 			xfers[i].tx_dma += offset;
3516 
3517 		/* Update length */
3518 		xfers[i].len = min(maxsize, xfers[i].len - offset);
3519 	}
3520 
3521 	/*
3522 	 * We set up xferp to the last entry we have inserted,
3523 	 * so that we skip those already split transfers.
3524 	 */
3525 	*xferp = &xfers[count - 1];
3526 
3527 	/* Increment statistics counters */
3528 	SPI_STATISTICS_INCREMENT_FIELD(ctlr->pcpu_statistics,
3529 				       transfers_split_maxsize);
3530 	SPI_STATISTICS_INCREMENT_FIELD(msg->spi->pcpu_statistics,
3531 				       transfers_split_maxsize);
3532 
3533 	return 0;
3534 }
3535 
3536 /**
3537  * spi_split_transfers_maxsize - split spi transfers into multiple transfers
3538  *                               when an individual transfer exceeds a
3539  *                               certain size
3540  * @ctlr:    the @spi_controller for this transfer
3541  * @msg:   the @spi_message to transform
3542  * @maxsize:  the maximum when to apply this
3543  * @gfp: GFP allocation flags
3544  *
3545  * Return: status of transformation
3546  */
spi_split_transfers_maxsize(struct spi_controller * ctlr,struct spi_message * msg,size_t maxsize,gfp_t gfp)3547 int spi_split_transfers_maxsize(struct spi_controller *ctlr,
3548 				struct spi_message *msg,
3549 				size_t maxsize,
3550 				gfp_t gfp)
3551 {
3552 	struct spi_transfer *xfer;
3553 	int ret;
3554 
3555 	/*
3556 	 * Iterate over the transfer_list,
3557 	 * but note that xfer is advanced to the last transfer inserted
3558 	 * to avoid checking sizes again unnecessarily (also xfer does
3559 	 * potentially belong to a different list by the time the
3560 	 * replacement has happened).
3561 	 */
3562 	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
3563 		if (xfer->len > maxsize) {
3564 			ret = __spi_split_transfer_maxsize(ctlr, msg, &xfer,
3565 							   maxsize, gfp);
3566 			if (ret)
3567 				return ret;
3568 		}
3569 	}
3570 
3571 	return 0;
3572 }
3573 EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize);
3574 
3575 /*-------------------------------------------------------------------------*/
3576 
3577 /* Core methods for SPI controller protocol drivers.  Some of the
3578  * other core methods are currently defined as inline functions.
3579  */
3580 
__spi_validate_bits_per_word(struct spi_controller * ctlr,u8 bits_per_word)3581 static int __spi_validate_bits_per_word(struct spi_controller *ctlr,
3582 					u8 bits_per_word)
3583 {
3584 	if (ctlr->bits_per_word_mask) {
3585 		/* Only 32 bits fit in the mask */
3586 		if (bits_per_word > 32)
3587 			return -EINVAL;
3588 		if (!(ctlr->bits_per_word_mask & SPI_BPW_MASK(bits_per_word)))
3589 			return -EINVAL;
3590 	}
3591 
3592 	return 0;
3593 }
3594 
3595 /**
3596  * spi_setup - setup SPI mode and clock rate
3597  * @spi: the device whose settings are being modified
3598  * Context: can sleep, and no requests are queued to the device
3599  *
3600  * SPI protocol drivers may need to update the transfer mode if the
3601  * device doesn't work with its default.  They may likewise need
3602  * to update clock rates or word sizes from initial values.  This function
3603  * changes those settings, and must be called from a context that can sleep.
3604  * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
3605  * effect the next time the device is selected and data is transferred to
3606  * or from it.  When this function returns, the spi device is deselected.
3607  *
3608  * Note that this call will fail if the protocol driver specifies an option
3609  * that the underlying controller or its driver does not support.  For
3610  * example, not all hardware supports wire transfers using nine bit words,
3611  * LSB-first wire encoding, or active-high chipselects.
3612  *
3613  * Return: zero on success, else a negative error code.
3614  */
spi_setup(struct spi_device * spi)3615 int spi_setup(struct spi_device *spi)
3616 {
3617 	unsigned	bad_bits, ugly_bits;
3618 	int		status = 0;
3619 
3620 	/*
3621 	 * Check mode to prevent that any two of DUAL, QUAD and NO_MOSI/MISO
3622 	 * are set at the same time.
3623 	 */
3624 	if ((hweight_long(spi->mode &
3625 		(SPI_TX_DUAL | SPI_TX_QUAD | SPI_NO_TX)) > 1) ||
3626 	    (hweight_long(spi->mode &
3627 		(SPI_RX_DUAL | SPI_RX_QUAD | SPI_NO_RX)) > 1)) {
3628 		dev_err(&spi->dev,
3629 		"setup: can not select any two of dual, quad and no-rx/tx at the same time\n");
3630 		return -EINVAL;
3631 	}
3632 	/* If it is SPI_3WIRE mode, DUAL and QUAD should be forbidden */
3633 	if ((spi->mode & SPI_3WIRE) && (spi->mode &
3634 		(SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
3635 		 SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL)))
3636 		return -EINVAL;
3637 	/*
3638 	 * Help drivers fail *cleanly* when they need options
3639 	 * that aren't supported with their current controller.
3640 	 * SPI_CS_WORD has a fallback software implementation,
3641 	 * so it is ignored here.
3642 	 */
3643 	bad_bits = spi->mode & ~(spi->controller->mode_bits | SPI_CS_WORD |
3644 				 SPI_NO_TX | SPI_NO_RX);
3645 	ugly_bits = bad_bits &
3646 		    (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
3647 		     SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL);
3648 	if (ugly_bits) {
3649 		dev_warn(&spi->dev,
3650 			 "setup: ignoring unsupported mode bits %x\n",
3651 			 ugly_bits);
3652 		spi->mode &= ~ugly_bits;
3653 		bad_bits &= ~ugly_bits;
3654 	}
3655 	if (bad_bits) {
3656 		dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
3657 			bad_bits);
3658 		return -EINVAL;
3659 	}
3660 
3661 	if (!spi->bits_per_word) {
3662 		spi->bits_per_word = 8;
3663 	} else {
3664 		/*
3665 		 * Some controllers may not support the default 8 bits-per-word
3666 		 * so only perform the check when this is explicitly provided.
3667 		 */
3668 		status = __spi_validate_bits_per_word(spi->controller,
3669 						      spi->bits_per_word);
3670 		if (status)
3671 			return status;
3672 	}
3673 
3674 	if (spi->controller->max_speed_hz &&
3675 	    (!spi->max_speed_hz ||
3676 	     spi->max_speed_hz > spi->controller->max_speed_hz))
3677 		spi->max_speed_hz = spi->controller->max_speed_hz;
3678 
3679 	mutex_lock(&spi->controller->io_mutex);
3680 
3681 	if (spi->controller->setup) {
3682 		status = spi->controller->setup(spi);
3683 		if (status) {
3684 			mutex_unlock(&spi->controller->io_mutex);
3685 			dev_err(&spi->controller->dev, "Failed to setup device: %d\n",
3686 				status);
3687 			return status;
3688 		}
3689 	}
3690 
3691 	if (spi->controller->auto_runtime_pm && spi->controller->set_cs) {
3692 		status = pm_runtime_resume_and_get(spi->controller->dev.parent);
3693 		if (status < 0) {
3694 			mutex_unlock(&spi->controller->io_mutex);
3695 			dev_err(&spi->controller->dev, "Failed to power device: %d\n",
3696 				status);
3697 			return status;
3698 		}
3699 
3700 		/*
3701 		 * We do not want to return positive value from pm_runtime_get,
3702 		 * there are many instances of devices calling spi_setup() and
3703 		 * checking for a non-zero return value instead of a negative
3704 		 * return value.
3705 		 */
3706 		status = 0;
3707 
3708 		spi_set_cs(spi, false, true);
3709 		pm_runtime_mark_last_busy(spi->controller->dev.parent);
3710 		pm_runtime_put_autosuspend(spi->controller->dev.parent);
3711 	} else {
3712 		spi_set_cs(spi, false, true);
3713 	}
3714 
3715 	mutex_unlock(&spi->controller->io_mutex);
3716 
3717 	if (spi->rt && !spi->controller->rt) {
3718 		spi->controller->rt = true;
3719 		spi_set_thread_rt(spi->controller);
3720 	}
3721 
3722 	trace_spi_setup(spi, status);
3723 
3724 	dev_dbg(&spi->dev, "setup mode %lu, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
3725 			spi->mode & SPI_MODE_X_MASK,
3726 			(spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
3727 			(spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
3728 			(spi->mode & SPI_3WIRE) ? "3wire, " : "",
3729 			(spi->mode & SPI_LOOP) ? "loopback, " : "",
3730 			spi->bits_per_word, spi->max_speed_hz,
3731 			status);
3732 
3733 	return status;
3734 }
3735 EXPORT_SYMBOL_GPL(spi_setup);
3736 
_spi_xfer_word_delay_update(struct spi_transfer * xfer,struct spi_device * spi)3737 static int _spi_xfer_word_delay_update(struct spi_transfer *xfer,
3738 				       struct spi_device *spi)
3739 {
3740 	int delay1, delay2;
3741 
3742 	delay1 = spi_delay_to_ns(&xfer->word_delay, xfer);
3743 	if (delay1 < 0)
3744 		return delay1;
3745 
3746 	delay2 = spi_delay_to_ns(&spi->word_delay, xfer);
3747 	if (delay2 < 0)
3748 		return delay2;
3749 
3750 	if (delay1 < delay2)
3751 		memcpy(&xfer->word_delay, &spi->word_delay,
3752 		       sizeof(xfer->word_delay));
3753 
3754 	return 0;
3755 }
3756 
__spi_validate(struct spi_device * spi,struct spi_message * message)3757 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
3758 {
3759 	struct spi_controller *ctlr = spi->controller;
3760 	struct spi_transfer *xfer;
3761 	int w_size;
3762 
3763 	if (list_empty(&message->transfers))
3764 		return -EINVAL;
3765 
3766 	/*
3767 	 * If an SPI controller does not support toggling the CS line on each
3768 	 * transfer (indicated by the SPI_CS_WORD flag) or we are using a GPIO
3769 	 * for the CS line, we can emulate the CS-per-word hardware function by
3770 	 * splitting transfers into one-word transfers and ensuring that
3771 	 * cs_change is set for each transfer.
3772 	 */
3773 	if ((spi->mode & SPI_CS_WORD) && (!(ctlr->mode_bits & SPI_CS_WORD) ||
3774 					  spi->cs_gpiod)) {
3775 		size_t maxsize;
3776 		int ret;
3777 
3778 		maxsize = (spi->bits_per_word + 7) / 8;
3779 
3780 		/* spi_split_transfers_maxsize() requires message->spi */
3781 		message->spi = spi;
3782 
3783 		ret = spi_split_transfers_maxsize(ctlr, message, maxsize,
3784 						  GFP_KERNEL);
3785 		if (ret)
3786 			return ret;
3787 
3788 		list_for_each_entry(xfer, &message->transfers, transfer_list) {
3789 			/* Don't change cs_change on the last entry in the list */
3790 			if (list_is_last(&xfer->transfer_list, &message->transfers))
3791 				break;
3792 			xfer->cs_change = 1;
3793 		}
3794 	}
3795 
3796 	/*
3797 	 * Half-duplex links include original MicroWire, and ones with
3798 	 * only one data pin like SPI_3WIRE (switches direction) or where
3799 	 * either MOSI or MISO is missing.  They can also be caused by
3800 	 * software limitations.
3801 	 */
3802 	if ((ctlr->flags & SPI_CONTROLLER_HALF_DUPLEX) ||
3803 	    (spi->mode & SPI_3WIRE)) {
3804 		unsigned flags = ctlr->flags;
3805 
3806 		list_for_each_entry(xfer, &message->transfers, transfer_list) {
3807 			if (xfer->rx_buf && xfer->tx_buf)
3808 				return -EINVAL;
3809 			if ((flags & SPI_CONTROLLER_NO_TX) && xfer->tx_buf)
3810 				return -EINVAL;
3811 			if ((flags & SPI_CONTROLLER_NO_RX) && xfer->rx_buf)
3812 				return -EINVAL;
3813 		}
3814 	}
3815 
3816 	/*
3817 	 * Set transfer bits_per_word and max speed as spi device default if
3818 	 * it is not set for this transfer.
3819 	 * Set transfer tx_nbits and rx_nbits as single transfer default
3820 	 * (SPI_NBITS_SINGLE) if it is not set for this transfer.
3821 	 * Ensure transfer word_delay is at least as long as that required by
3822 	 * device itself.
3823 	 */
3824 	message->frame_length = 0;
3825 	list_for_each_entry(xfer, &message->transfers, transfer_list) {
3826 		xfer->effective_speed_hz = 0;
3827 		message->frame_length += xfer->len;
3828 		if (!xfer->bits_per_word)
3829 			xfer->bits_per_word = spi->bits_per_word;
3830 
3831 		if (!xfer->speed_hz)
3832 			xfer->speed_hz = spi->max_speed_hz;
3833 
3834 		if (ctlr->max_speed_hz && xfer->speed_hz > ctlr->max_speed_hz)
3835 			xfer->speed_hz = ctlr->max_speed_hz;
3836 
3837 		if (__spi_validate_bits_per_word(ctlr, xfer->bits_per_word))
3838 			return -EINVAL;
3839 
3840 		/*
3841 		 * SPI transfer length should be multiple of SPI word size
3842 		 * where SPI word size should be power-of-two multiple.
3843 		 */
3844 		if (xfer->bits_per_word <= 8)
3845 			w_size = 1;
3846 		else if (xfer->bits_per_word <= 16)
3847 			w_size = 2;
3848 		else
3849 			w_size = 4;
3850 
3851 		/* No partial transfers accepted */
3852 		if (xfer->len % w_size)
3853 			return -EINVAL;
3854 
3855 		if (xfer->speed_hz && ctlr->min_speed_hz &&
3856 		    xfer->speed_hz < ctlr->min_speed_hz)
3857 			return -EINVAL;
3858 
3859 		if (xfer->tx_buf && !xfer->tx_nbits)
3860 			xfer->tx_nbits = SPI_NBITS_SINGLE;
3861 		if (xfer->rx_buf && !xfer->rx_nbits)
3862 			xfer->rx_nbits = SPI_NBITS_SINGLE;
3863 		/*
3864 		 * Check transfer tx/rx_nbits:
3865 		 * 1. check the value matches one of single, dual and quad
3866 		 * 2. check tx/rx_nbits match the mode in spi_device
3867 		 */
3868 		if (xfer->tx_buf) {
3869 			if (spi->mode & SPI_NO_TX)
3870 				return -EINVAL;
3871 			if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
3872 				xfer->tx_nbits != SPI_NBITS_DUAL &&
3873 				xfer->tx_nbits != SPI_NBITS_QUAD)
3874 				return -EINVAL;
3875 			if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
3876 				!(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
3877 				return -EINVAL;
3878 			if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
3879 				!(spi->mode & SPI_TX_QUAD))
3880 				return -EINVAL;
3881 		}
3882 		/* Check transfer rx_nbits */
3883 		if (xfer->rx_buf) {
3884 			if (spi->mode & SPI_NO_RX)
3885 				return -EINVAL;
3886 			if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
3887 				xfer->rx_nbits != SPI_NBITS_DUAL &&
3888 				xfer->rx_nbits != SPI_NBITS_QUAD)
3889 				return -EINVAL;
3890 			if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
3891 				!(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
3892 				return -EINVAL;
3893 			if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
3894 				!(spi->mode & SPI_RX_QUAD))
3895 				return -EINVAL;
3896 		}
3897 
3898 		if (_spi_xfer_word_delay_update(xfer, spi))
3899 			return -EINVAL;
3900 	}
3901 
3902 	message->status = -EINPROGRESS;
3903 
3904 	return 0;
3905 }
3906 
__spi_async(struct spi_device * spi,struct spi_message * message)3907 static int __spi_async(struct spi_device *spi, struct spi_message *message)
3908 {
3909 	struct spi_controller *ctlr = spi->controller;
3910 	struct spi_transfer *xfer;
3911 
3912 	/*
3913 	 * Some controllers do not support doing regular SPI transfers. Return
3914 	 * ENOTSUPP when this is the case.
3915 	 */
3916 	if (!ctlr->transfer)
3917 		return -ENOTSUPP;
3918 
3919 	message->spi = spi;
3920 
3921 	SPI_STATISTICS_INCREMENT_FIELD(ctlr->pcpu_statistics, spi_async);
3922 	SPI_STATISTICS_INCREMENT_FIELD(spi->pcpu_statistics, spi_async);
3923 
3924 	trace_spi_message_submit(message);
3925 
3926 	if (!ctlr->ptp_sts_supported) {
3927 		list_for_each_entry(xfer, &message->transfers, transfer_list) {
3928 			xfer->ptp_sts_word_pre = 0;
3929 			ptp_read_system_prets(xfer->ptp_sts);
3930 		}
3931 	}
3932 
3933 	return ctlr->transfer(spi, message);
3934 }
3935 
3936 /**
3937  * spi_async - asynchronous SPI transfer
3938  * @spi: device with which data will be exchanged
3939  * @message: describes the data transfers, including completion callback
3940  * Context: any (irqs may be blocked, etc)
3941  *
3942  * This call may be used in_irq and other contexts which can't sleep,
3943  * as well as from task contexts which can sleep.
3944  *
3945  * The completion callback is invoked in a context which can't sleep.
3946  * Before that invocation, the value of message->status is undefined.
3947  * When the callback is issued, message->status holds either zero (to
3948  * indicate complete success) or a negative error code.  After that
3949  * callback returns, the driver which issued the transfer request may
3950  * deallocate the associated memory; it's no longer in use by any SPI
3951  * core or controller driver code.
3952  *
3953  * Note that although all messages to a spi_device are handled in
3954  * FIFO order, messages may go to different devices in other orders.
3955  * Some device might be higher priority, or have various "hard" access
3956  * time requirements, for example.
3957  *
3958  * On detection of any fault during the transfer, processing of
3959  * the entire message is aborted, and the device is deselected.
3960  * Until returning from the associated message completion callback,
3961  * no other spi_message queued to that device will be processed.
3962  * (This rule applies equally to all the synchronous transfer calls,
3963  * which are wrappers around this core asynchronous primitive.)
3964  *
3965  * Return: zero on success, else a negative error code.
3966  */
spi_async(struct spi_device * spi,struct spi_message * message)3967 int spi_async(struct spi_device *spi, struct spi_message *message)
3968 {
3969 	struct spi_controller *ctlr = spi->controller;
3970 	int ret;
3971 	unsigned long flags;
3972 
3973 	ret = __spi_validate(spi, message);
3974 	if (ret != 0)
3975 		return ret;
3976 
3977 	spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3978 
3979 	if (ctlr->bus_lock_flag)
3980 		ret = -EBUSY;
3981 	else
3982 		ret = __spi_async(spi, message);
3983 
3984 	spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3985 
3986 	return ret;
3987 }
3988 EXPORT_SYMBOL_GPL(spi_async);
3989 
3990 /**
3991  * spi_async_locked - version of spi_async with exclusive bus usage
3992  * @spi: device with which data will be exchanged
3993  * @message: describes the data transfers, including completion callback
3994  * Context: any (irqs may be blocked, etc)
3995  *
3996  * This call may be used in_irq and other contexts which can't sleep,
3997  * as well as from task contexts which can sleep.
3998  *
3999  * The completion callback is invoked in a context which can't sleep.
4000  * Before that invocation, the value of message->status is undefined.
4001  * When the callback is issued, message->status holds either zero (to
4002  * indicate complete success) or a negative error code.  After that
4003  * callback returns, the driver which issued the transfer request may
4004  * deallocate the associated memory; it's no longer in use by any SPI
4005  * core or controller driver code.
4006  *
4007  * Note that although all messages to a spi_device are handled in
4008  * FIFO order, messages may go to different devices in other orders.
4009  * Some device might be higher priority, or have various "hard" access
4010  * time requirements, for example.
4011  *
4012  * On detection of any fault during the transfer, processing of
4013  * the entire message is aborted, and the device is deselected.
4014  * Until returning from the associated message completion callback,
4015  * no other spi_message queued to that device will be processed.
4016  * (This rule applies equally to all the synchronous transfer calls,
4017  * which are wrappers around this core asynchronous primitive.)
4018  *
4019  * Return: zero on success, else a negative error code.
4020  */
spi_async_locked(struct spi_device * spi,struct spi_message * message)4021 static int spi_async_locked(struct spi_device *spi, struct spi_message *message)
4022 {
4023 	struct spi_controller *ctlr = spi->controller;
4024 	int ret;
4025 	unsigned long flags;
4026 
4027 	ret = __spi_validate(spi, message);
4028 	if (ret != 0)
4029 		return ret;
4030 
4031 	spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
4032 
4033 	ret = __spi_async(spi, message);
4034 
4035 	spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
4036 
4037 	return ret;
4038 
4039 }
4040 
__spi_transfer_message_noqueue(struct spi_controller * ctlr,struct spi_message * msg)4041 static void __spi_transfer_message_noqueue(struct spi_controller *ctlr, struct spi_message *msg)
4042 {
4043 	bool was_busy;
4044 	int ret;
4045 
4046 	mutex_lock(&ctlr->io_mutex);
4047 
4048 	was_busy = ctlr->busy;
4049 
4050 	ctlr->cur_msg = msg;
4051 	ret = __spi_pump_transfer_message(ctlr, msg, was_busy);
4052 	if (ret)
4053 		goto out;
4054 
4055 	ctlr->cur_msg = NULL;
4056 	ctlr->fallback = false;
4057 
4058 	if (!was_busy) {
4059 		kfree(ctlr->dummy_rx);
4060 		ctlr->dummy_rx = NULL;
4061 		kfree(ctlr->dummy_tx);
4062 		ctlr->dummy_tx = NULL;
4063 		if (ctlr->unprepare_transfer_hardware &&
4064 		    ctlr->unprepare_transfer_hardware(ctlr))
4065 			dev_err(&ctlr->dev,
4066 				"failed to unprepare transfer hardware\n");
4067 		spi_idle_runtime_pm(ctlr);
4068 	}
4069 
4070 out:
4071 	mutex_unlock(&ctlr->io_mutex);
4072 }
4073 
4074 /*-------------------------------------------------------------------------*/
4075 
4076 /*
4077  * Utility methods for SPI protocol drivers, layered on
4078  * top of the core.  Some other utility methods are defined as
4079  * inline functions.
4080  */
4081 
spi_complete(void * arg)4082 static void spi_complete(void *arg)
4083 {
4084 	complete(arg);
4085 }
4086 
__spi_sync(struct spi_device * spi,struct spi_message * message)4087 static int __spi_sync(struct spi_device *spi, struct spi_message *message)
4088 {
4089 	DECLARE_COMPLETION_ONSTACK(done);
4090 	int status;
4091 	struct spi_controller *ctlr = spi->controller;
4092 
4093 	status = __spi_validate(spi, message);
4094 	if (status != 0)
4095 		return status;
4096 
4097 	message->spi = spi;
4098 
4099 	SPI_STATISTICS_INCREMENT_FIELD(ctlr->pcpu_statistics, spi_sync);
4100 	SPI_STATISTICS_INCREMENT_FIELD(spi->pcpu_statistics, spi_sync);
4101 
4102 	/*
4103 	 * Checking queue_empty here only guarantees async/sync message
4104 	 * ordering when coming from the same context. It does not need to
4105 	 * guard against reentrancy from a different context. The io_mutex
4106 	 * will catch those cases.
4107 	 */
4108 	if (READ_ONCE(ctlr->queue_empty) && !ctlr->must_async) {
4109 		message->actual_length = 0;
4110 		message->status = -EINPROGRESS;
4111 
4112 		trace_spi_message_submit(message);
4113 
4114 		SPI_STATISTICS_INCREMENT_FIELD(ctlr->pcpu_statistics, spi_sync_immediate);
4115 		SPI_STATISTICS_INCREMENT_FIELD(spi->pcpu_statistics, spi_sync_immediate);
4116 
4117 		__spi_transfer_message_noqueue(ctlr, message);
4118 
4119 		return message->status;
4120 	}
4121 
4122 	/*
4123 	 * There are messages in the async queue that could have originated
4124 	 * from the same context, so we need to preserve ordering.
4125 	 * Therefor we send the message to the async queue and wait until they
4126 	 * are completed.
4127 	 */
4128 	message->complete = spi_complete;
4129 	message->context = &done;
4130 	status = spi_async_locked(spi, message);
4131 	if (status == 0) {
4132 		wait_for_completion(&done);
4133 		status = message->status;
4134 	}
4135 	message->context = NULL;
4136 
4137 	return status;
4138 }
4139 
4140 /**
4141  * spi_sync - blocking/synchronous SPI data transfers
4142  * @spi: device with which data will be exchanged
4143  * @message: describes the data transfers
4144  * Context: can sleep
4145  *
4146  * This call may only be used from a context that may sleep.  The sleep
4147  * is non-interruptible, and has no timeout.  Low-overhead controller
4148  * drivers may DMA directly into and out of the message buffers.
4149  *
4150  * Note that the SPI device's chip select is active during the message,
4151  * and then is normally disabled between messages.  Drivers for some
4152  * frequently-used devices may want to minimize costs of selecting a chip,
4153  * by leaving it selected in anticipation that the next message will go
4154  * to the same chip.  (That may increase power usage.)
4155  *
4156  * Also, the caller is guaranteeing that the memory associated with the
4157  * message will not be freed before this call returns.
4158  *
4159  * Return: zero on success, else a negative error code.
4160  */
spi_sync(struct spi_device * spi,struct spi_message * message)4161 int spi_sync(struct spi_device *spi, struct spi_message *message)
4162 {
4163 	int ret;
4164 
4165 	mutex_lock(&spi->controller->bus_lock_mutex);
4166 	ret = __spi_sync(spi, message);
4167 	mutex_unlock(&spi->controller->bus_lock_mutex);
4168 
4169 	return ret;
4170 }
4171 EXPORT_SYMBOL_GPL(spi_sync);
4172 
4173 /**
4174  * spi_sync_locked - version of spi_sync with exclusive bus usage
4175  * @spi: device with which data will be exchanged
4176  * @message: describes the data transfers
4177  * Context: can sleep
4178  *
4179  * This call may only be used from a context that may sleep.  The sleep
4180  * is non-interruptible, and has no timeout.  Low-overhead controller
4181  * drivers may DMA directly into and out of the message buffers.
4182  *
4183  * This call should be used by drivers that require exclusive access to the
4184  * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
4185  * be released by a spi_bus_unlock call when the exclusive access is over.
4186  *
4187  * Return: zero on success, else a negative error code.
4188  */
spi_sync_locked(struct spi_device * spi,struct spi_message * message)4189 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
4190 {
4191 	return __spi_sync(spi, message);
4192 }
4193 EXPORT_SYMBOL_GPL(spi_sync_locked);
4194 
4195 /**
4196  * spi_bus_lock - obtain a lock for exclusive SPI bus usage
4197  * @ctlr: SPI bus master that should be locked for exclusive bus access
4198  * Context: can sleep
4199  *
4200  * This call may only be used from a context that may sleep.  The sleep
4201  * is non-interruptible, and has no timeout.
4202  *
4203  * This call should be used by drivers that require exclusive access to the
4204  * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
4205  * exclusive access is over. Data transfer must be done by spi_sync_locked
4206  * and spi_async_locked calls when the SPI bus lock is held.
4207  *
4208  * Return: always zero.
4209  */
spi_bus_lock(struct spi_controller * ctlr)4210 int spi_bus_lock(struct spi_controller *ctlr)
4211 {
4212 	unsigned long flags;
4213 
4214 	mutex_lock(&ctlr->bus_lock_mutex);
4215 
4216 	spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
4217 	ctlr->bus_lock_flag = 1;
4218 	spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
4219 
4220 	/* Mutex remains locked until spi_bus_unlock() is called */
4221 
4222 	return 0;
4223 }
4224 EXPORT_SYMBOL_GPL(spi_bus_lock);
4225 
4226 /**
4227  * spi_bus_unlock - release the lock for exclusive SPI bus usage
4228  * @ctlr: SPI bus master that was locked for exclusive bus access
4229  * Context: can sleep
4230  *
4231  * This call may only be used from a context that may sleep.  The sleep
4232  * is non-interruptible, and has no timeout.
4233  *
4234  * This call releases an SPI bus lock previously obtained by an spi_bus_lock
4235  * call.
4236  *
4237  * Return: always zero.
4238  */
spi_bus_unlock(struct spi_controller * ctlr)4239 int spi_bus_unlock(struct spi_controller *ctlr)
4240 {
4241 	ctlr->bus_lock_flag = 0;
4242 
4243 	mutex_unlock(&ctlr->bus_lock_mutex);
4244 
4245 	return 0;
4246 }
4247 EXPORT_SYMBOL_GPL(spi_bus_unlock);
4248 
4249 /* Portable code must never pass more than 32 bytes */
4250 #define	SPI_BUFSIZ	max(32, SMP_CACHE_BYTES)
4251 
4252 static u8	*buf;
4253 
4254 /**
4255  * spi_write_then_read - SPI synchronous write followed by read
4256  * @spi: device with which data will be exchanged
4257  * @txbuf: data to be written (need not be dma-safe)
4258  * @n_tx: size of txbuf, in bytes
4259  * @rxbuf: buffer into which data will be read (need not be dma-safe)
4260  * @n_rx: size of rxbuf, in bytes
4261  * Context: can sleep
4262  *
4263  * This performs a half duplex MicroWire style transaction with the
4264  * device, sending txbuf and then reading rxbuf.  The return value
4265  * is zero for success, else a negative errno status code.
4266  * This call may only be used from a context that may sleep.
4267  *
4268  * Parameters to this routine are always copied using a small buffer.
4269  * Performance-sensitive or bulk transfer code should instead use
4270  * spi_{async,sync}() calls with dma-safe buffers.
4271  *
4272  * Return: zero on success, else a negative error code.
4273  */
spi_write_then_read(struct spi_device * spi,const void * txbuf,unsigned n_tx,void * rxbuf,unsigned n_rx)4274 int spi_write_then_read(struct spi_device *spi,
4275 		const void *txbuf, unsigned n_tx,
4276 		void *rxbuf, unsigned n_rx)
4277 {
4278 	static DEFINE_MUTEX(lock);
4279 
4280 	int			status;
4281 	struct spi_message	message;
4282 	struct spi_transfer	x[2];
4283 	u8			*local_buf;
4284 
4285 	/*
4286 	 * Use preallocated DMA-safe buffer if we can. We can't avoid
4287 	 * copying here, (as a pure convenience thing), but we can
4288 	 * keep heap costs out of the hot path unless someone else is
4289 	 * using the pre-allocated buffer or the transfer is too large.
4290 	 */
4291 	if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
4292 		local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
4293 				    GFP_KERNEL | GFP_DMA);
4294 		if (!local_buf)
4295 			return -ENOMEM;
4296 	} else {
4297 		local_buf = buf;
4298 	}
4299 
4300 	spi_message_init(&message);
4301 	memset(x, 0, sizeof(x));
4302 	if (n_tx) {
4303 		x[0].len = n_tx;
4304 		spi_message_add_tail(&x[0], &message);
4305 	}
4306 	if (n_rx) {
4307 		x[1].len = n_rx;
4308 		spi_message_add_tail(&x[1], &message);
4309 	}
4310 
4311 	memcpy(local_buf, txbuf, n_tx);
4312 	x[0].tx_buf = local_buf;
4313 	x[1].rx_buf = local_buf + n_tx;
4314 
4315 	/* Do the i/o */
4316 	status = spi_sync(spi, &message);
4317 	if (status == 0)
4318 		memcpy(rxbuf, x[1].rx_buf, n_rx);
4319 
4320 	if (x[0].tx_buf == buf)
4321 		mutex_unlock(&lock);
4322 	else
4323 		kfree(local_buf);
4324 
4325 	return status;
4326 }
4327 EXPORT_SYMBOL_GPL(spi_write_then_read);
4328 
4329 /*-------------------------------------------------------------------------*/
4330 
4331 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
4332 /* Must call put_device() when done with returned spi_device device */
of_find_spi_device_by_node(struct device_node * node)4333 static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
4334 {
4335 	struct device *dev = bus_find_device_by_of_node(&spi_bus_type, node);
4336 
4337 	return dev ? to_spi_device(dev) : NULL;
4338 }
4339 
4340 /* The spi controllers are not using spi_bus, so we find it with another way */
of_find_spi_controller_by_node(struct device_node * node)4341 static struct spi_controller *of_find_spi_controller_by_node(struct device_node *node)
4342 {
4343 	struct device *dev;
4344 
4345 	dev = class_find_device_by_of_node(&spi_master_class, node);
4346 	if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
4347 		dev = class_find_device_by_of_node(&spi_slave_class, node);
4348 	if (!dev)
4349 		return NULL;
4350 
4351 	/* Reference got in class_find_device */
4352 	return container_of(dev, struct spi_controller, dev);
4353 }
4354 
of_spi_notify(struct notifier_block * nb,unsigned long action,void * arg)4355 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
4356 			 void *arg)
4357 {
4358 	struct of_reconfig_data *rd = arg;
4359 	struct spi_controller *ctlr;
4360 	struct spi_device *spi;
4361 
4362 	switch (of_reconfig_get_state_change(action, arg)) {
4363 	case OF_RECONFIG_CHANGE_ADD:
4364 		ctlr = of_find_spi_controller_by_node(rd->dn->parent);
4365 		if (ctlr == NULL)
4366 			return NOTIFY_OK;	/* Not for us */
4367 
4368 		if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
4369 			put_device(&ctlr->dev);
4370 			return NOTIFY_OK;
4371 		}
4372 
4373 		spi = of_register_spi_device(ctlr, rd->dn);
4374 		put_device(&ctlr->dev);
4375 
4376 		if (IS_ERR(spi)) {
4377 			pr_err("%s: failed to create for '%pOF'\n",
4378 					__func__, rd->dn);
4379 			of_node_clear_flag(rd->dn, OF_POPULATED);
4380 			return notifier_from_errno(PTR_ERR(spi));
4381 		}
4382 		break;
4383 
4384 	case OF_RECONFIG_CHANGE_REMOVE:
4385 		/* Already depopulated? */
4386 		if (!of_node_check_flag(rd->dn, OF_POPULATED))
4387 			return NOTIFY_OK;
4388 
4389 		/* Find our device by node */
4390 		spi = of_find_spi_device_by_node(rd->dn);
4391 		if (spi == NULL)
4392 			return NOTIFY_OK;	/* No? not meant for us */
4393 
4394 		/* Unregister takes one ref away */
4395 		spi_unregister_device(spi);
4396 
4397 		/* And put the reference of the find */
4398 		put_device(&spi->dev);
4399 		break;
4400 	}
4401 
4402 	return NOTIFY_OK;
4403 }
4404 
4405 static struct notifier_block spi_of_notifier = {
4406 	.notifier_call = of_spi_notify,
4407 };
4408 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
4409 extern struct notifier_block spi_of_notifier;
4410 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
4411 
4412 #if IS_ENABLED(CONFIG_ACPI)
spi_acpi_controller_match(struct device * dev,const void * data)4413 static int spi_acpi_controller_match(struct device *dev, const void *data)
4414 {
4415 	return ACPI_COMPANION(dev->parent) == data;
4416 }
4417 
acpi_spi_find_controller_by_adev(struct acpi_device * adev)4418 static struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev)
4419 {
4420 	struct device *dev;
4421 
4422 	dev = class_find_device(&spi_master_class, NULL, adev,
4423 				spi_acpi_controller_match);
4424 	if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
4425 		dev = class_find_device(&spi_slave_class, NULL, adev,
4426 					spi_acpi_controller_match);
4427 	if (!dev)
4428 		return NULL;
4429 
4430 	return container_of(dev, struct spi_controller, dev);
4431 }
4432 
acpi_spi_find_device_by_adev(struct acpi_device * adev)4433 static struct spi_device *acpi_spi_find_device_by_adev(struct acpi_device *adev)
4434 {
4435 	struct device *dev;
4436 
4437 	dev = bus_find_device_by_acpi_dev(&spi_bus_type, adev);
4438 	return to_spi_device(dev);
4439 }
4440 
acpi_spi_notify(struct notifier_block * nb,unsigned long value,void * arg)4441 static int acpi_spi_notify(struct notifier_block *nb, unsigned long value,
4442 			   void *arg)
4443 {
4444 	struct acpi_device *adev = arg;
4445 	struct spi_controller *ctlr;
4446 	struct spi_device *spi;
4447 
4448 	switch (value) {
4449 	case ACPI_RECONFIG_DEVICE_ADD:
4450 		ctlr = acpi_spi_find_controller_by_adev(acpi_dev_parent(adev));
4451 		if (!ctlr)
4452 			break;
4453 
4454 		acpi_register_spi_device(ctlr, adev);
4455 		put_device(&ctlr->dev);
4456 		break;
4457 	case ACPI_RECONFIG_DEVICE_REMOVE:
4458 		if (!acpi_device_enumerated(adev))
4459 			break;
4460 
4461 		spi = acpi_spi_find_device_by_adev(adev);
4462 		if (!spi)
4463 			break;
4464 
4465 		spi_unregister_device(spi);
4466 		put_device(&spi->dev);
4467 		break;
4468 	}
4469 
4470 	return NOTIFY_OK;
4471 }
4472 
4473 static struct notifier_block spi_acpi_notifier = {
4474 	.notifier_call = acpi_spi_notify,
4475 };
4476 #else
4477 extern struct notifier_block spi_acpi_notifier;
4478 #endif
4479 
spi_init(void)4480 static int __init spi_init(void)
4481 {
4482 	int	status;
4483 
4484 	buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
4485 	if (!buf) {
4486 		status = -ENOMEM;
4487 		goto err0;
4488 	}
4489 
4490 	status = bus_register(&spi_bus_type);
4491 	if (status < 0)
4492 		goto err1;
4493 
4494 	status = class_register(&spi_master_class);
4495 	if (status < 0)
4496 		goto err2;
4497 
4498 	if (IS_ENABLED(CONFIG_SPI_SLAVE)) {
4499 		status = class_register(&spi_slave_class);
4500 		if (status < 0)
4501 			goto err3;
4502 	}
4503 
4504 	if (IS_ENABLED(CONFIG_OF_DYNAMIC))
4505 		WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
4506 	if (IS_ENABLED(CONFIG_ACPI))
4507 		WARN_ON(acpi_reconfig_notifier_register(&spi_acpi_notifier));
4508 
4509 	return 0;
4510 
4511 err3:
4512 	class_unregister(&spi_master_class);
4513 err2:
4514 	bus_unregister(&spi_bus_type);
4515 err1:
4516 	kfree(buf);
4517 	buf = NULL;
4518 err0:
4519 	return status;
4520 }
4521 
4522 /*
4523  * A board_info is normally registered in arch_initcall(),
4524  * but even essential drivers wait till later.
4525  *
4526  * REVISIT only boardinfo really needs static linking. The rest (device and
4527  * driver registration) _could_ be dynamically linked (modular) ... Costs
4528  * include needing to have boardinfo data structures be much more public.
4529  */
4530 postcore_initcall(spi_init);
4531