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/acpi.h>
8 #include <linux/cache.h>
9 #include <linux/clk/clk-conf.h>
10 #include <linux/delay.h>
11 #include <linux/device.h>
12 #include <linux/dmaengine.h>
13 #include <linux/dma-mapping.h>
14 #include <linux/export.h>
15 #include <linux/gpio/consumer.h>
16 #include <linux/highmem.h>
17 #include <linux/idr.h>
18 #include <linux/init.h>
19 #include <linux/ioport.h>
20 #include <linux/kernel.h>
21 #include <linux/kthread.h>
22 #include <linux/mod_devicetable.h>
23 #include <linux/mutex.h>
24 #include <linux/of_device.h>
25 #include <linux/of_irq.h>
26 #include <linux/percpu.h>
27 #include <linux/platform_data/x86/apple.h>
28 #include <linux/pm_domain.h>
29 #include <linux/pm_runtime.h>
30 #include <linux/property.h>
31 #include <linux/ptp_clock_kernel.h>
32 #include <linux/sched/rt.h>
33 #include <linux/slab.h>
34 #include <linux/spi/spi.h>
35 #include <linux/spi/spi-mem.h>
36 #include <uapi/linux/sched/types.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 sysfs_emit(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 = sysfs_emit(buf, "%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
spi_emit_pcpu_stats(struct spi_statistics __percpu * stat,char * buf,size_t offset)120 static ssize_t spi_emit_pcpu_stats(struct spi_statistics __percpu *stat,
121 char *buf, size_t offset)
122 {
123 u64 val = 0;
124 int i;
125
126 for_each_possible_cpu(i) {
127 const struct spi_statistics *pcpu_stats;
128 u64_stats_t *field;
129 unsigned int start;
130 u64 inc;
131
132 pcpu_stats = per_cpu_ptr(stat, i);
133 field = (void *)pcpu_stats + offset;
134 do {
135 start = u64_stats_fetch_begin(&pcpu_stats->syncp);
136 inc = u64_stats_read(field);
137 } while (u64_stats_fetch_retry(&pcpu_stats->syncp, start));
138 val += inc;
139 }
140 return sysfs_emit(buf, "%llu\n", val);
141 }
142
143 #define SPI_STATISTICS_ATTRS(field, file) \
144 static ssize_t spi_controller_##field##_show(struct device *dev, \
145 struct device_attribute *attr, \
146 char *buf) \
147 { \
148 struct spi_controller *ctlr = container_of(dev, \
149 struct spi_controller, dev); \
150 return spi_statistics_##field##_show(ctlr->pcpu_statistics, buf); \
151 } \
152 static struct device_attribute dev_attr_spi_controller_##field = { \
153 .attr = { .name = file, .mode = 0444 }, \
154 .show = spi_controller_##field##_show, \
155 }; \
156 static ssize_t spi_device_##field##_show(struct device *dev, \
157 struct device_attribute *attr, \
158 char *buf) \
159 { \
160 struct spi_device *spi = to_spi_device(dev); \
161 return spi_statistics_##field##_show(spi->pcpu_statistics, buf); \
162 } \
163 static struct device_attribute dev_attr_spi_device_##field = { \
164 .attr = { .name = file, .mode = 0444 }, \
165 .show = spi_device_##field##_show, \
166 }
167
168 #define SPI_STATISTICS_SHOW_NAME(name, file, field) \
169 static ssize_t spi_statistics_##name##_show(struct spi_statistics __percpu *stat, \
170 char *buf) \
171 { \
172 return spi_emit_pcpu_stats(stat, buf, \
173 offsetof(struct spi_statistics, field)); \
174 } \
175 SPI_STATISTICS_ATTRS(name, file)
176
177 #define SPI_STATISTICS_SHOW(field) \
178 SPI_STATISTICS_SHOW_NAME(field, __stringify(field), \
179 field)
180
181 SPI_STATISTICS_SHOW(messages);
182 SPI_STATISTICS_SHOW(transfers);
183 SPI_STATISTICS_SHOW(errors);
184 SPI_STATISTICS_SHOW(timedout);
185
186 SPI_STATISTICS_SHOW(spi_sync);
187 SPI_STATISTICS_SHOW(spi_sync_immediate);
188 SPI_STATISTICS_SHOW(spi_async);
189
190 SPI_STATISTICS_SHOW(bytes);
191 SPI_STATISTICS_SHOW(bytes_rx);
192 SPI_STATISTICS_SHOW(bytes_tx);
193
194 #define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number) \
195 SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index, \
196 "transfer_bytes_histo_" number, \
197 transfer_bytes_histo[index])
198 SPI_STATISTICS_TRANSFER_BYTES_HISTO(0, "0-1");
199 SPI_STATISTICS_TRANSFER_BYTES_HISTO(1, "2-3");
200 SPI_STATISTICS_TRANSFER_BYTES_HISTO(2, "4-7");
201 SPI_STATISTICS_TRANSFER_BYTES_HISTO(3, "8-15");
202 SPI_STATISTICS_TRANSFER_BYTES_HISTO(4, "16-31");
203 SPI_STATISTICS_TRANSFER_BYTES_HISTO(5, "32-63");
204 SPI_STATISTICS_TRANSFER_BYTES_HISTO(6, "64-127");
205 SPI_STATISTICS_TRANSFER_BYTES_HISTO(7, "128-255");
206 SPI_STATISTICS_TRANSFER_BYTES_HISTO(8, "256-511");
207 SPI_STATISTICS_TRANSFER_BYTES_HISTO(9, "512-1023");
208 SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
209 SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
210 SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
211 SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
212 SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
213 SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
214 SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
215
216 SPI_STATISTICS_SHOW(transfers_split_maxsize);
217
218 static struct attribute *spi_dev_attrs[] = {
219 &dev_attr_modalias.attr,
220 &dev_attr_driver_override.attr,
221 NULL,
222 };
223
224 static const struct attribute_group spi_dev_group = {
225 .attrs = spi_dev_attrs,
226 };
227
228 static struct attribute *spi_device_statistics_attrs[] = {
229 &dev_attr_spi_device_messages.attr,
230 &dev_attr_spi_device_transfers.attr,
231 &dev_attr_spi_device_errors.attr,
232 &dev_attr_spi_device_timedout.attr,
233 &dev_attr_spi_device_spi_sync.attr,
234 &dev_attr_spi_device_spi_sync_immediate.attr,
235 &dev_attr_spi_device_spi_async.attr,
236 &dev_attr_spi_device_bytes.attr,
237 &dev_attr_spi_device_bytes_rx.attr,
238 &dev_attr_spi_device_bytes_tx.attr,
239 &dev_attr_spi_device_transfer_bytes_histo0.attr,
240 &dev_attr_spi_device_transfer_bytes_histo1.attr,
241 &dev_attr_spi_device_transfer_bytes_histo2.attr,
242 &dev_attr_spi_device_transfer_bytes_histo3.attr,
243 &dev_attr_spi_device_transfer_bytes_histo4.attr,
244 &dev_attr_spi_device_transfer_bytes_histo5.attr,
245 &dev_attr_spi_device_transfer_bytes_histo6.attr,
246 &dev_attr_spi_device_transfer_bytes_histo7.attr,
247 &dev_attr_spi_device_transfer_bytes_histo8.attr,
248 &dev_attr_spi_device_transfer_bytes_histo9.attr,
249 &dev_attr_spi_device_transfer_bytes_histo10.attr,
250 &dev_attr_spi_device_transfer_bytes_histo11.attr,
251 &dev_attr_spi_device_transfer_bytes_histo12.attr,
252 &dev_attr_spi_device_transfer_bytes_histo13.attr,
253 &dev_attr_spi_device_transfer_bytes_histo14.attr,
254 &dev_attr_spi_device_transfer_bytes_histo15.attr,
255 &dev_attr_spi_device_transfer_bytes_histo16.attr,
256 &dev_attr_spi_device_transfers_split_maxsize.attr,
257 NULL,
258 };
259
260 static const struct attribute_group spi_device_statistics_group = {
261 .name = "statistics",
262 .attrs = spi_device_statistics_attrs,
263 };
264
265 static const struct attribute_group *spi_dev_groups[] = {
266 &spi_dev_group,
267 &spi_device_statistics_group,
268 NULL,
269 };
270
271 static struct attribute *spi_controller_statistics_attrs[] = {
272 &dev_attr_spi_controller_messages.attr,
273 &dev_attr_spi_controller_transfers.attr,
274 &dev_attr_spi_controller_errors.attr,
275 &dev_attr_spi_controller_timedout.attr,
276 &dev_attr_spi_controller_spi_sync.attr,
277 &dev_attr_spi_controller_spi_sync_immediate.attr,
278 &dev_attr_spi_controller_spi_async.attr,
279 &dev_attr_spi_controller_bytes.attr,
280 &dev_attr_spi_controller_bytes_rx.attr,
281 &dev_attr_spi_controller_bytes_tx.attr,
282 &dev_attr_spi_controller_transfer_bytes_histo0.attr,
283 &dev_attr_spi_controller_transfer_bytes_histo1.attr,
284 &dev_attr_spi_controller_transfer_bytes_histo2.attr,
285 &dev_attr_spi_controller_transfer_bytes_histo3.attr,
286 &dev_attr_spi_controller_transfer_bytes_histo4.attr,
287 &dev_attr_spi_controller_transfer_bytes_histo5.attr,
288 &dev_attr_spi_controller_transfer_bytes_histo6.attr,
289 &dev_attr_spi_controller_transfer_bytes_histo7.attr,
290 &dev_attr_spi_controller_transfer_bytes_histo8.attr,
291 &dev_attr_spi_controller_transfer_bytes_histo9.attr,
292 &dev_attr_spi_controller_transfer_bytes_histo10.attr,
293 &dev_attr_spi_controller_transfer_bytes_histo11.attr,
294 &dev_attr_spi_controller_transfer_bytes_histo12.attr,
295 &dev_attr_spi_controller_transfer_bytes_histo13.attr,
296 &dev_attr_spi_controller_transfer_bytes_histo14.attr,
297 &dev_attr_spi_controller_transfer_bytes_histo15.attr,
298 &dev_attr_spi_controller_transfer_bytes_histo16.attr,
299 &dev_attr_spi_controller_transfers_split_maxsize.attr,
300 NULL,
301 };
302
303 static const struct attribute_group spi_controller_statistics_group = {
304 .name = "statistics",
305 .attrs = spi_controller_statistics_attrs,
306 };
307
308 static const struct attribute_group *spi_master_groups[] = {
309 &spi_controller_statistics_group,
310 NULL,
311 };
312
spi_statistics_add_transfer_stats(struct spi_statistics __percpu * pcpu_stats,struct spi_transfer * xfer,struct spi_controller * ctlr)313 static void spi_statistics_add_transfer_stats(struct spi_statistics __percpu *pcpu_stats,
314 struct spi_transfer *xfer,
315 struct spi_controller *ctlr)
316 {
317 int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
318 struct spi_statistics *stats;
319
320 if (l2len < 0)
321 l2len = 0;
322
323 get_cpu();
324 stats = this_cpu_ptr(pcpu_stats);
325 u64_stats_update_begin(&stats->syncp);
326
327 u64_stats_inc(&stats->transfers);
328 u64_stats_inc(&stats->transfer_bytes_histo[l2len]);
329
330 u64_stats_add(&stats->bytes, xfer->len);
331 if ((xfer->tx_buf) &&
332 (xfer->tx_buf != ctlr->dummy_tx))
333 u64_stats_add(&stats->bytes_tx, xfer->len);
334 if ((xfer->rx_buf) &&
335 (xfer->rx_buf != ctlr->dummy_rx))
336 u64_stats_add(&stats->bytes_rx, xfer->len);
337
338 u64_stats_update_end(&stats->syncp);
339 put_cpu();
340 }
341
342 /*
343 * modalias support makes "modprobe $MODALIAS" new-style hotplug work,
344 * and the sysfs version makes coldplug work too.
345 */
spi_match_id(const struct spi_device_id * id,const char * name)346 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id, const char *name)
347 {
348 while (id->name[0]) {
349 if (!strcmp(name, id->name))
350 return id;
351 id++;
352 }
353 return NULL;
354 }
355
spi_get_device_id(const struct spi_device * sdev)356 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
357 {
358 const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
359
360 return spi_match_id(sdrv->id_table, sdev->modalias);
361 }
362 EXPORT_SYMBOL_GPL(spi_get_device_id);
363
spi_get_device_match_data(const struct spi_device * sdev)364 const void *spi_get_device_match_data(const struct spi_device *sdev)
365 {
366 const void *match;
367
368 match = device_get_match_data(&sdev->dev);
369 if (match)
370 return match;
371
372 return (const void *)spi_get_device_id(sdev)->driver_data;
373 }
374 EXPORT_SYMBOL_GPL(spi_get_device_match_data);
375
spi_match_device(struct device * dev,struct device_driver * drv)376 static int spi_match_device(struct device *dev, struct device_driver *drv)
377 {
378 const struct spi_device *spi = to_spi_device(dev);
379 const struct spi_driver *sdrv = to_spi_driver(drv);
380
381 /* Check override first, and if set, only use the named driver */
382 if (spi->driver_override)
383 return strcmp(spi->driver_override, drv->name) == 0;
384
385 /* Attempt an OF style match */
386 if (of_driver_match_device(dev, drv))
387 return 1;
388
389 /* Then try ACPI */
390 if (acpi_driver_match_device(dev, drv))
391 return 1;
392
393 if (sdrv->id_table)
394 return !!spi_match_id(sdrv->id_table, spi->modalias);
395
396 return strcmp(spi->modalias, drv->name) == 0;
397 }
398
spi_uevent(const struct device * dev,struct kobj_uevent_env * env)399 static int spi_uevent(const struct device *dev, struct kobj_uevent_env *env)
400 {
401 const struct spi_device *spi = to_spi_device(dev);
402 int rc;
403
404 rc = acpi_device_uevent_modalias(dev, env);
405 if (rc != -ENODEV)
406 return rc;
407
408 return add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
409 }
410
spi_probe(struct device * dev)411 static int spi_probe(struct device *dev)
412 {
413 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
414 struct spi_device *spi = to_spi_device(dev);
415 int ret;
416
417 ret = of_clk_set_defaults(dev->of_node, false);
418 if (ret)
419 return ret;
420
421 if (dev->of_node) {
422 spi->irq = of_irq_get(dev->of_node, 0);
423 if (spi->irq == -EPROBE_DEFER)
424 return -EPROBE_DEFER;
425 if (spi->irq < 0)
426 spi->irq = 0;
427 }
428
429 ret = dev_pm_domain_attach(dev, true);
430 if (ret)
431 return ret;
432
433 if (sdrv->probe) {
434 ret = sdrv->probe(spi);
435 if (ret)
436 dev_pm_domain_detach(dev, true);
437 }
438
439 return ret;
440 }
441
spi_remove(struct device * dev)442 static void spi_remove(struct device *dev)
443 {
444 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
445
446 if (sdrv->remove)
447 sdrv->remove(to_spi_device(dev));
448
449 dev_pm_domain_detach(dev, true);
450 }
451
spi_shutdown(struct device * dev)452 static void spi_shutdown(struct device *dev)
453 {
454 if (dev->driver) {
455 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
456
457 if (sdrv->shutdown)
458 sdrv->shutdown(to_spi_device(dev));
459 }
460 }
461
462 struct bus_type spi_bus_type = {
463 .name = "spi",
464 .dev_groups = spi_dev_groups,
465 .match = spi_match_device,
466 .uevent = spi_uevent,
467 .probe = spi_probe,
468 .remove = spi_remove,
469 .shutdown = spi_shutdown,
470 };
471 EXPORT_SYMBOL_GPL(spi_bus_type);
472
473 /**
474 * __spi_register_driver - register a SPI driver
475 * @owner: owner module of the driver to register
476 * @sdrv: the driver to register
477 * Context: can sleep
478 *
479 * Return: zero on success, else a negative error code.
480 */
__spi_register_driver(struct module * owner,struct spi_driver * sdrv)481 int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
482 {
483 sdrv->driver.owner = owner;
484 sdrv->driver.bus = &spi_bus_type;
485
486 /*
487 * For Really Good Reasons we use spi: modaliases not of:
488 * modaliases for DT so module autoloading won't work if we
489 * don't have a spi_device_id as well as a compatible string.
490 */
491 if (sdrv->driver.of_match_table) {
492 const struct of_device_id *of_id;
493
494 for (of_id = sdrv->driver.of_match_table; of_id->compatible[0];
495 of_id++) {
496 const char *of_name;
497
498 /* Strip off any vendor prefix */
499 of_name = strnchr(of_id->compatible,
500 sizeof(of_id->compatible), ',');
501 if (of_name)
502 of_name++;
503 else
504 of_name = of_id->compatible;
505
506 if (sdrv->id_table) {
507 const struct spi_device_id *spi_id;
508
509 spi_id = spi_match_id(sdrv->id_table, of_name);
510 if (spi_id)
511 continue;
512 } else {
513 if (strcmp(sdrv->driver.name, of_name) == 0)
514 continue;
515 }
516
517 pr_warn("SPI driver %s has no spi_device_id for %s\n",
518 sdrv->driver.name, of_id->compatible);
519 }
520 }
521
522 return driver_register(&sdrv->driver);
523 }
524 EXPORT_SYMBOL_GPL(__spi_register_driver);
525
526 /*-------------------------------------------------------------------------*/
527
528 /*
529 * SPI devices should normally not be created by SPI device drivers; that
530 * would make them board-specific. Similarly with SPI controller drivers.
531 * Device registration normally goes into like arch/.../mach.../board-YYY.c
532 * with other readonly (flashable) information about mainboard devices.
533 */
534
535 struct boardinfo {
536 struct list_head list;
537 struct spi_board_info board_info;
538 };
539
540 static LIST_HEAD(board_list);
541 static LIST_HEAD(spi_controller_list);
542
543 /*
544 * Used to protect add/del operation for board_info list and
545 * spi_controller list, and their matching process also used
546 * to protect object of type struct idr.
547 */
548 static DEFINE_MUTEX(board_lock);
549
550 /**
551 * spi_alloc_device - Allocate a new SPI device
552 * @ctlr: Controller to which device is connected
553 * Context: can sleep
554 *
555 * Allows a driver to allocate and initialize a spi_device without
556 * registering it immediately. This allows a driver to directly
557 * fill the spi_device with device parameters before calling
558 * spi_add_device() on it.
559 *
560 * Caller is responsible to call spi_add_device() on the returned
561 * spi_device structure to add it to the SPI controller. If the caller
562 * needs to discard the spi_device without adding it, then it should
563 * call spi_dev_put() on it.
564 *
565 * Return: a pointer to the new device, or NULL.
566 */
spi_alloc_device(struct spi_controller * ctlr)567 struct spi_device *spi_alloc_device(struct spi_controller *ctlr)
568 {
569 struct spi_device *spi;
570
571 if (!spi_controller_get(ctlr))
572 return NULL;
573
574 spi = kzalloc(sizeof(*spi), GFP_KERNEL);
575 if (!spi) {
576 spi_controller_put(ctlr);
577 return NULL;
578 }
579
580 spi->pcpu_statistics = spi_alloc_pcpu_stats(NULL);
581 if (!spi->pcpu_statistics) {
582 kfree(spi);
583 spi_controller_put(ctlr);
584 return NULL;
585 }
586
587 spi->master = spi->controller = ctlr;
588 spi->dev.parent = &ctlr->dev;
589 spi->dev.bus = &spi_bus_type;
590 spi->dev.release = spidev_release;
591 spi->mode = ctlr->buswidth_override_bits;
592
593 device_initialize(&spi->dev);
594 return spi;
595 }
596 EXPORT_SYMBOL_GPL(spi_alloc_device);
597
spi_dev_set_name(struct spi_device * spi)598 static void spi_dev_set_name(struct spi_device *spi)
599 {
600 struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
601
602 if (adev) {
603 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
604 return;
605 }
606
607 dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->controller->dev),
608 spi_get_chipselect(spi, 0));
609 }
610
spi_dev_check(struct device * dev,void * data)611 static int spi_dev_check(struct device *dev, void *data)
612 {
613 struct spi_device *spi = to_spi_device(dev);
614 struct spi_device *new_spi = data;
615
616 if (spi->controller == new_spi->controller &&
617 spi_get_chipselect(spi, 0) == spi_get_chipselect(new_spi, 0))
618 return -EBUSY;
619 return 0;
620 }
621
spi_cleanup(struct spi_device * spi)622 static void spi_cleanup(struct spi_device *spi)
623 {
624 if (spi->controller->cleanup)
625 spi->controller->cleanup(spi);
626 }
627
__spi_add_device(struct spi_device * spi)628 static int __spi_add_device(struct spi_device *spi)
629 {
630 struct spi_controller *ctlr = spi->controller;
631 struct device *dev = ctlr->dev.parent;
632 int status;
633
634 /* Chipselects are numbered 0..max; validate. */
635 if (spi_get_chipselect(spi, 0) >= ctlr->num_chipselect) {
636 dev_err(dev, "cs%d >= max %d\n", spi_get_chipselect(spi, 0),
637 ctlr->num_chipselect);
638 return -EINVAL;
639 }
640
641 /* Set the bus ID string */
642 spi_dev_set_name(spi);
643
644 /*
645 * We need to make sure there's no other device with this
646 * chipselect **BEFORE** we call setup(), else we'll trash
647 * its configuration.
648 */
649 status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
650 if (status) {
651 dev_err(dev, "chipselect %d already in use\n",
652 spi_get_chipselect(spi, 0));
653 return status;
654 }
655
656 /* Controller may unregister concurrently */
657 if (IS_ENABLED(CONFIG_SPI_DYNAMIC) &&
658 !device_is_registered(&ctlr->dev)) {
659 return -ENODEV;
660 }
661
662 if (ctlr->cs_gpiods)
663 spi_set_csgpiod(spi, 0, ctlr->cs_gpiods[spi_get_chipselect(spi, 0)]);
664
665 /*
666 * Drivers may modify this initial i/o setup, but will
667 * normally rely on the device being setup. Devices
668 * using SPI_CS_HIGH can't coexist well otherwise...
669 */
670 status = spi_setup(spi);
671 if (status < 0) {
672 dev_err(dev, "can't setup %s, status %d\n",
673 dev_name(&spi->dev), status);
674 return status;
675 }
676
677 /* Device may be bound to an active driver when this returns */
678 status = device_add(&spi->dev);
679 if (status < 0) {
680 dev_err(dev, "can't add %s, status %d\n",
681 dev_name(&spi->dev), status);
682 spi_cleanup(spi);
683 } else {
684 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
685 }
686
687 return status;
688 }
689
690 /**
691 * spi_add_device - Add spi_device allocated with spi_alloc_device
692 * @spi: spi_device to register
693 *
694 * Companion function to spi_alloc_device. Devices allocated with
695 * spi_alloc_device can be added onto the SPI bus with this function.
696 *
697 * Return: 0 on success; negative errno on failure
698 */
spi_add_device(struct spi_device * spi)699 int spi_add_device(struct spi_device *spi)
700 {
701 struct spi_controller *ctlr = spi->controller;
702 int status;
703
704 mutex_lock(&ctlr->add_lock);
705 status = __spi_add_device(spi);
706 mutex_unlock(&ctlr->add_lock);
707 return status;
708 }
709 EXPORT_SYMBOL_GPL(spi_add_device);
710
711 /**
712 * spi_new_device - instantiate one new SPI device
713 * @ctlr: Controller to which device is connected
714 * @chip: Describes the SPI device
715 * Context: can sleep
716 *
717 * On typical mainboards, this is purely internal; and it's not needed
718 * after board init creates the hard-wired devices. Some development
719 * platforms may not be able to use spi_register_board_info though, and
720 * this is exported so that for example a USB or parport based adapter
721 * driver could add devices (which it would learn about out-of-band).
722 *
723 * Return: the new device, or NULL.
724 */
spi_new_device(struct spi_controller * ctlr,struct spi_board_info * chip)725 struct spi_device *spi_new_device(struct spi_controller *ctlr,
726 struct spi_board_info *chip)
727 {
728 struct spi_device *proxy;
729 int status;
730
731 /*
732 * NOTE: caller did any chip->bus_num checks necessary.
733 *
734 * Also, unless we change the return value convention to use
735 * error-or-pointer (not NULL-or-pointer), troubleshootability
736 * suggests syslogged diagnostics are best here (ugh).
737 */
738
739 proxy = spi_alloc_device(ctlr);
740 if (!proxy)
741 return NULL;
742
743 WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
744
745 spi_set_chipselect(proxy, 0, chip->chip_select);
746 proxy->max_speed_hz = chip->max_speed_hz;
747 proxy->mode = chip->mode;
748 proxy->irq = chip->irq;
749 strscpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
750 proxy->dev.platform_data = (void *) chip->platform_data;
751 proxy->controller_data = chip->controller_data;
752 proxy->controller_state = NULL;
753
754 if (chip->swnode) {
755 status = device_add_software_node(&proxy->dev, chip->swnode);
756 if (status) {
757 dev_err(&ctlr->dev, "failed to add software node to '%s': %d\n",
758 chip->modalias, status);
759 goto err_dev_put;
760 }
761 }
762
763 status = spi_add_device(proxy);
764 if (status < 0)
765 goto err_dev_put;
766
767 return proxy;
768
769 err_dev_put:
770 device_remove_software_node(&proxy->dev);
771 spi_dev_put(proxy);
772 return NULL;
773 }
774 EXPORT_SYMBOL_GPL(spi_new_device);
775
776 /**
777 * spi_unregister_device - unregister a single SPI device
778 * @spi: spi_device to unregister
779 *
780 * Start making the passed SPI device vanish. Normally this would be handled
781 * by spi_unregister_controller().
782 */
spi_unregister_device(struct spi_device * spi)783 void spi_unregister_device(struct spi_device *spi)
784 {
785 if (!spi)
786 return;
787
788 if (spi->dev.of_node) {
789 of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
790 of_node_put(spi->dev.of_node);
791 }
792 if (ACPI_COMPANION(&spi->dev))
793 acpi_device_clear_enumerated(ACPI_COMPANION(&spi->dev));
794 device_remove_software_node(&spi->dev);
795 device_del(&spi->dev);
796 spi_cleanup(spi);
797 put_device(&spi->dev);
798 }
799 EXPORT_SYMBOL_GPL(spi_unregister_device);
800
spi_match_controller_to_boardinfo(struct spi_controller * ctlr,struct spi_board_info * bi)801 static void spi_match_controller_to_boardinfo(struct spi_controller *ctlr,
802 struct spi_board_info *bi)
803 {
804 struct spi_device *dev;
805
806 if (ctlr->bus_num != bi->bus_num)
807 return;
808
809 dev = spi_new_device(ctlr, bi);
810 if (!dev)
811 dev_err(ctlr->dev.parent, "can't create new device for %s\n",
812 bi->modalias);
813 }
814
815 /**
816 * spi_register_board_info - register SPI devices for a given board
817 * @info: array of chip descriptors
818 * @n: how many descriptors are provided
819 * Context: can sleep
820 *
821 * Board-specific early init code calls this (probably during arch_initcall)
822 * with segments of the SPI device table. Any device nodes are created later,
823 * after the relevant parent SPI controller (bus_num) is defined. We keep
824 * this table of devices forever, so that reloading a controller driver will
825 * not make Linux forget about these hard-wired devices.
826 *
827 * Other code can also call this, e.g. a particular add-on board might provide
828 * SPI devices through its expansion connector, so code initializing that board
829 * would naturally declare its SPI devices.
830 *
831 * The board info passed can safely be __initdata ... but be careful of
832 * any embedded pointers (platform_data, etc), they're copied as-is.
833 *
834 * Return: zero on success, else a negative error code.
835 */
spi_register_board_info(struct spi_board_info const * info,unsigned n)836 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
837 {
838 struct boardinfo *bi;
839 int i;
840
841 if (!n)
842 return 0;
843
844 bi = kcalloc(n, sizeof(*bi), GFP_KERNEL);
845 if (!bi)
846 return -ENOMEM;
847
848 for (i = 0; i < n; i++, bi++, info++) {
849 struct spi_controller *ctlr;
850
851 memcpy(&bi->board_info, info, sizeof(*info));
852
853 mutex_lock(&board_lock);
854 list_add_tail(&bi->list, &board_list);
855 list_for_each_entry(ctlr, &spi_controller_list, list)
856 spi_match_controller_to_boardinfo(ctlr,
857 &bi->board_info);
858 mutex_unlock(&board_lock);
859 }
860
861 return 0;
862 }
863
864 /*-------------------------------------------------------------------------*/
865
866 /* Core methods for SPI resource management */
867
868 /**
869 * spi_res_alloc - allocate a spi resource that is life-cycle managed
870 * during the processing of a spi_message while using
871 * spi_transfer_one
872 * @spi: the SPI device for which we allocate memory
873 * @release: the release code to execute for this resource
874 * @size: size to alloc and return
875 * @gfp: GFP allocation flags
876 *
877 * Return: the pointer to the allocated data
878 *
879 * This may get enhanced in the future to allocate from a memory pool
880 * of the @spi_device or @spi_controller to avoid repeated allocations.
881 */
spi_res_alloc(struct spi_device * spi,spi_res_release_t release,size_t size,gfp_t gfp)882 static void *spi_res_alloc(struct spi_device *spi, spi_res_release_t release,
883 size_t size, gfp_t gfp)
884 {
885 struct spi_res *sres;
886
887 sres = kzalloc(sizeof(*sres) + size, gfp);
888 if (!sres)
889 return NULL;
890
891 INIT_LIST_HEAD(&sres->entry);
892 sres->release = release;
893
894 return sres->data;
895 }
896
897 /**
898 * spi_res_free - free an SPI resource
899 * @res: pointer to the custom data of a resource
900 */
spi_res_free(void * res)901 static void spi_res_free(void *res)
902 {
903 struct spi_res *sres = container_of(res, struct spi_res, data);
904
905 if (!res)
906 return;
907
908 WARN_ON(!list_empty(&sres->entry));
909 kfree(sres);
910 }
911
912 /**
913 * spi_res_add - add a spi_res to the spi_message
914 * @message: the SPI message
915 * @res: the spi_resource
916 */
spi_res_add(struct spi_message * message,void * res)917 static void spi_res_add(struct spi_message *message, void *res)
918 {
919 struct spi_res *sres = container_of(res, struct spi_res, data);
920
921 WARN_ON(!list_empty(&sres->entry));
922 list_add_tail(&sres->entry, &message->resources);
923 }
924
925 /**
926 * spi_res_release - release all SPI resources for this message
927 * @ctlr: the @spi_controller
928 * @message: the @spi_message
929 */
spi_res_release(struct spi_controller * ctlr,struct spi_message * message)930 static void spi_res_release(struct spi_controller *ctlr, struct spi_message *message)
931 {
932 struct spi_res *res, *tmp;
933
934 list_for_each_entry_safe_reverse(res, tmp, &message->resources, entry) {
935 if (res->release)
936 res->release(ctlr, message, res->data);
937
938 list_del(&res->entry);
939
940 kfree(res);
941 }
942 }
943
944 /*-------------------------------------------------------------------------*/
945
spi_set_cs(struct spi_device * spi,bool enable,bool force)946 static void spi_set_cs(struct spi_device *spi, bool enable, bool force)
947 {
948 bool activate = enable;
949
950 /*
951 * Avoid calling into the driver (or doing delays) if the chip select
952 * isn't actually changing from the last time this was called.
953 */
954 if (!force && ((enable && spi->controller->last_cs == spi_get_chipselect(spi, 0)) ||
955 (!enable && spi->controller->last_cs != spi_get_chipselect(spi, 0))) &&
956 (spi->controller->last_cs_mode_high == (spi->mode & SPI_CS_HIGH)))
957 return;
958
959 trace_spi_set_cs(spi, activate);
960
961 spi->controller->last_cs = enable ? spi_get_chipselect(spi, 0) : -1;
962 spi->controller->last_cs_mode_high = spi->mode & SPI_CS_HIGH;
963
964 if ((spi_get_csgpiod(spi, 0) || !spi->controller->set_cs_timing) && !activate)
965 spi_delay_exec(&spi->cs_hold, NULL);
966
967 if (spi->mode & SPI_CS_HIGH)
968 enable = !enable;
969
970 if (spi_get_csgpiod(spi, 0)) {
971 if (!(spi->mode & SPI_NO_CS)) {
972 /*
973 * Historically ACPI has no means of the GPIO polarity and
974 * thus the SPISerialBus() resource defines it on the per-chip
975 * basis. In order to avoid a chain of negations, the GPIO
976 * polarity is considered being Active High. Even for the cases
977 * when _DSD() is involved (in the updated versions of ACPI)
978 * the GPIO CS polarity must be defined Active High to avoid
979 * ambiguity. That's why we use enable, that takes SPI_CS_HIGH
980 * into account.
981 */
982 if (has_acpi_companion(&spi->dev))
983 gpiod_set_value_cansleep(spi_get_csgpiod(spi, 0), !enable);
984 else
985 /* Polarity handled by GPIO library */
986 gpiod_set_value_cansleep(spi_get_csgpiod(spi, 0), activate);
987 }
988 /* Some SPI masters need both GPIO CS & slave_select */
989 if ((spi->controller->flags & SPI_CONTROLLER_GPIO_SS) &&
990 spi->controller->set_cs)
991 spi->controller->set_cs(spi, !enable);
992 } else if (spi->controller->set_cs) {
993 spi->controller->set_cs(spi, !enable);
994 }
995
996 if (spi_get_csgpiod(spi, 0) || !spi->controller->set_cs_timing) {
997 if (activate)
998 spi_delay_exec(&spi->cs_setup, NULL);
999 else
1000 spi_delay_exec(&spi->cs_inactive, NULL);
1001 }
1002 }
1003
1004 #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)1005 static int spi_map_buf_attrs(struct spi_controller *ctlr, struct device *dev,
1006 struct sg_table *sgt, void *buf, size_t len,
1007 enum dma_data_direction dir, unsigned long attrs)
1008 {
1009 const bool vmalloced_buf = is_vmalloc_addr(buf);
1010 unsigned int max_seg_size = dma_get_max_seg_size(dev);
1011 #ifdef CONFIG_HIGHMEM
1012 const bool kmap_buf = ((unsigned long)buf >= PKMAP_BASE &&
1013 (unsigned long)buf < (PKMAP_BASE +
1014 (LAST_PKMAP * PAGE_SIZE)));
1015 #else
1016 const bool kmap_buf = false;
1017 #endif
1018 int desc_len;
1019 int sgs;
1020 struct page *vm_page;
1021 struct scatterlist *sg;
1022 void *sg_buf;
1023 size_t min;
1024 int i, ret;
1025
1026 if (vmalloced_buf || kmap_buf) {
1027 desc_len = min_t(unsigned long, max_seg_size, PAGE_SIZE);
1028 sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
1029 } else if (virt_addr_valid(buf)) {
1030 desc_len = min_t(size_t, max_seg_size, ctlr->max_dma_len);
1031 sgs = DIV_ROUND_UP(len, desc_len);
1032 } else {
1033 return -EINVAL;
1034 }
1035
1036 ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
1037 if (ret != 0)
1038 return ret;
1039
1040 sg = &sgt->sgl[0];
1041 for (i = 0; i < sgs; i++) {
1042
1043 if (vmalloced_buf || kmap_buf) {
1044 /*
1045 * Next scatterlist entry size is the minimum between
1046 * the desc_len and the remaining buffer length that
1047 * fits in a page.
1048 */
1049 min = min_t(size_t, desc_len,
1050 min_t(size_t, len,
1051 PAGE_SIZE - offset_in_page(buf)));
1052 if (vmalloced_buf)
1053 vm_page = vmalloc_to_page(buf);
1054 else
1055 vm_page = kmap_to_page(buf);
1056 if (!vm_page) {
1057 sg_free_table(sgt);
1058 return -ENOMEM;
1059 }
1060 sg_set_page(sg, vm_page,
1061 min, offset_in_page(buf));
1062 } else {
1063 min = min_t(size_t, len, desc_len);
1064 sg_buf = buf;
1065 sg_set_buf(sg, sg_buf, min);
1066 }
1067
1068 buf += min;
1069 len -= min;
1070 sg = sg_next(sg);
1071 }
1072
1073 ret = dma_map_sgtable(dev, sgt, dir, attrs);
1074 if (ret < 0) {
1075 sg_free_table(sgt);
1076 return ret;
1077 }
1078
1079 return 0;
1080 }
1081
spi_map_buf(struct spi_controller * ctlr,struct device * dev,struct sg_table * sgt,void * buf,size_t len,enum dma_data_direction dir)1082 int spi_map_buf(struct spi_controller *ctlr, struct device *dev,
1083 struct sg_table *sgt, void *buf, size_t len,
1084 enum dma_data_direction dir)
1085 {
1086 return spi_map_buf_attrs(ctlr, dev, sgt, buf, len, dir, 0);
1087 }
1088
spi_unmap_buf_attrs(struct spi_controller * ctlr,struct device * dev,struct sg_table * sgt,enum dma_data_direction dir,unsigned long attrs)1089 static void spi_unmap_buf_attrs(struct spi_controller *ctlr,
1090 struct device *dev, struct sg_table *sgt,
1091 enum dma_data_direction dir,
1092 unsigned long attrs)
1093 {
1094 if (sgt->orig_nents) {
1095 dma_unmap_sgtable(dev, sgt, dir, attrs);
1096 sg_free_table(sgt);
1097 sgt->orig_nents = 0;
1098 sgt->nents = 0;
1099 }
1100 }
1101
spi_unmap_buf(struct spi_controller * ctlr,struct device * dev,struct sg_table * sgt,enum dma_data_direction dir)1102 void spi_unmap_buf(struct spi_controller *ctlr, struct device *dev,
1103 struct sg_table *sgt, enum dma_data_direction dir)
1104 {
1105 spi_unmap_buf_attrs(ctlr, dev, sgt, dir, 0);
1106 }
1107
__spi_map_msg(struct spi_controller * ctlr,struct spi_message * msg)1108 static int __spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
1109 {
1110 struct device *tx_dev, *rx_dev;
1111 struct spi_transfer *xfer;
1112 int ret;
1113
1114 if (!ctlr->can_dma)
1115 return 0;
1116
1117 if (ctlr->dma_tx)
1118 tx_dev = ctlr->dma_tx->device->dev;
1119 else if (ctlr->dma_map_dev)
1120 tx_dev = ctlr->dma_map_dev;
1121 else
1122 tx_dev = ctlr->dev.parent;
1123
1124 if (ctlr->dma_rx)
1125 rx_dev = ctlr->dma_rx->device->dev;
1126 else if (ctlr->dma_map_dev)
1127 rx_dev = ctlr->dma_map_dev;
1128 else
1129 rx_dev = ctlr->dev.parent;
1130
1131 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1132 /* The sync is done before each transfer. */
1133 unsigned long attrs = DMA_ATTR_SKIP_CPU_SYNC;
1134
1135 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
1136 continue;
1137
1138 if (xfer->tx_buf != NULL) {
1139 ret = spi_map_buf_attrs(ctlr, tx_dev, &xfer->tx_sg,
1140 (void *)xfer->tx_buf,
1141 xfer->len, DMA_TO_DEVICE,
1142 attrs);
1143 if (ret != 0)
1144 return ret;
1145 }
1146
1147 if (xfer->rx_buf != NULL) {
1148 ret = spi_map_buf_attrs(ctlr, rx_dev, &xfer->rx_sg,
1149 xfer->rx_buf, xfer->len,
1150 DMA_FROM_DEVICE, attrs);
1151 if (ret != 0) {
1152 spi_unmap_buf_attrs(ctlr, tx_dev,
1153 &xfer->tx_sg, DMA_TO_DEVICE,
1154 attrs);
1155
1156 return ret;
1157 }
1158 }
1159 }
1160
1161 ctlr->cur_rx_dma_dev = rx_dev;
1162 ctlr->cur_tx_dma_dev = tx_dev;
1163 ctlr->cur_msg_mapped = true;
1164
1165 return 0;
1166 }
1167
__spi_unmap_msg(struct spi_controller * ctlr,struct spi_message * msg)1168 static int __spi_unmap_msg(struct spi_controller *ctlr, struct spi_message *msg)
1169 {
1170 struct device *rx_dev = ctlr->cur_rx_dma_dev;
1171 struct device *tx_dev = ctlr->cur_tx_dma_dev;
1172 struct spi_transfer *xfer;
1173
1174 if (!ctlr->cur_msg_mapped || !ctlr->can_dma)
1175 return 0;
1176
1177 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1178 /* The sync has already been done after each transfer. */
1179 unsigned long attrs = DMA_ATTR_SKIP_CPU_SYNC;
1180
1181 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
1182 continue;
1183
1184 spi_unmap_buf_attrs(ctlr, rx_dev, &xfer->rx_sg,
1185 DMA_FROM_DEVICE, attrs);
1186 spi_unmap_buf_attrs(ctlr, tx_dev, &xfer->tx_sg,
1187 DMA_TO_DEVICE, attrs);
1188 }
1189
1190 ctlr->cur_msg_mapped = false;
1191
1192 return 0;
1193 }
1194
spi_dma_sync_for_device(struct spi_controller * ctlr,struct spi_transfer * xfer)1195 static void spi_dma_sync_for_device(struct spi_controller *ctlr,
1196 struct spi_transfer *xfer)
1197 {
1198 struct device *rx_dev = ctlr->cur_rx_dma_dev;
1199 struct device *tx_dev = ctlr->cur_tx_dma_dev;
1200
1201 if (!ctlr->cur_msg_mapped)
1202 return;
1203
1204 if (xfer->tx_sg.orig_nents)
1205 dma_sync_sgtable_for_device(tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
1206 if (xfer->rx_sg.orig_nents)
1207 dma_sync_sgtable_for_device(rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
1208 }
1209
spi_dma_sync_for_cpu(struct spi_controller * ctlr,struct spi_transfer * xfer)1210 static void spi_dma_sync_for_cpu(struct spi_controller *ctlr,
1211 struct spi_transfer *xfer)
1212 {
1213 struct device *rx_dev = ctlr->cur_rx_dma_dev;
1214 struct device *tx_dev = ctlr->cur_tx_dma_dev;
1215
1216 if (!ctlr->cur_msg_mapped)
1217 return;
1218
1219 if (xfer->rx_sg.orig_nents)
1220 dma_sync_sgtable_for_cpu(rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
1221 if (xfer->tx_sg.orig_nents)
1222 dma_sync_sgtable_for_cpu(tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
1223 }
1224 #else /* !CONFIG_HAS_DMA */
__spi_map_msg(struct spi_controller * ctlr,struct spi_message * msg)1225 static inline int __spi_map_msg(struct spi_controller *ctlr,
1226 struct spi_message *msg)
1227 {
1228 return 0;
1229 }
1230
__spi_unmap_msg(struct spi_controller * ctlr,struct spi_message * msg)1231 static inline int __spi_unmap_msg(struct spi_controller *ctlr,
1232 struct spi_message *msg)
1233 {
1234 return 0;
1235 }
1236
spi_dma_sync_for_device(struct spi_controller * ctrl,struct spi_transfer * xfer)1237 static void spi_dma_sync_for_device(struct spi_controller *ctrl,
1238 struct spi_transfer *xfer)
1239 {
1240 }
1241
spi_dma_sync_for_cpu(struct spi_controller * ctrl,struct spi_transfer * xfer)1242 static void spi_dma_sync_for_cpu(struct spi_controller *ctrl,
1243 struct spi_transfer *xfer)
1244 {
1245 }
1246 #endif /* !CONFIG_HAS_DMA */
1247
spi_unmap_msg(struct spi_controller * ctlr,struct spi_message * msg)1248 static inline int spi_unmap_msg(struct spi_controller *ctlr,
1249 struct spi_message *msg)
1250 {
1251 struct spi_transfer *xfer;
1252
1253 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1254 /*
1255 * Restore the original value of tx_buf or rx_buf if they are
1256 * NULL.
1257 */
1258 if (xfer->tx_buf == ctlr->dummy_tx)
1259 xfer->tx_buf = NULL;
1260 if (xfer->rx_buf == ctlr->dummy_rx)
1261 xfer->rx_buf = NULL;
1262 }
1263
1264 return __spi_unmap_msg(ctlr, msg);
1265 }
1266
spi_map_msg(struct spi_controller * ctlr,struct spi_message * msg)1267 static int spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
1268 {
1269 struct spi_transfer *xfer;
1270 void *tmp;
1271 unsigned int max_tx, max_rx;
1272
1273 if ((ctlr->flags & (SPI_CONTROLLER_MUST_RX | SPI_CONTROLLER_MUST_TX))
1274 && !(msg->spi->mode & SPI_3WIRE)) {
1275 max_tx = 0;
1276 max_rx = 0;
1277
1278 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1279 if ((ctlr->flags & SPI_CONTROLLER_MUST_TX) &&
1280 !xfer->tx_buf)
1281 max_tx = max(xfer->len, max_tx);
1282 if ((ctlr->flags & SPI_CONTROLLER_MUST_RX) &&
1283 !xfer->rx_buf)
1284 max_rx = max(xfer->len, max_rx);
1285 }
1286
1287 if (max_tx) {
1288 tmp = krealloc(ctlr->dummy_tx, max_tx,
1289 GFP_KERNEL | GFP_DMA | __GFP_ZERO);
1290 if (!tmp)
1291 return -ENOMEM;
1292 ctlr->dummy_tx = tmp;
1293 }
1294
1295 if (max_rx) {
1296 tmp = krealloc(ctlr->dummy_rx, max_rx,
1297 GFP_KERNEL | GFP_DMA);
1298 if (!tmp)
1299 return -ENOMEM;
1300 ctlr->dummy_rx = tmp;
1301 }
1302
1303 if (max_tx || max_rx) {
1304 list_for_each_entry(xfer, &msg->transfers,
1305 transfer_list) {
1306 if (!xfer->len)
1307 continue;
1308 if (!xfer->tx_buf)
1309 xfer->tx_buf = ctlr->dummy_tx;
1310 if (!xfer->rx_buf)
1311 xfer->rx_buf = ctlr->dummy_rx;
1312 }
1313 }
1314 }
1315
1316 return __spi_map_msg(ctlr, msg);
1317 }
1318
spi_transfer_wait(struct spi_controller * ctlr,struct spi_message * msg,struct spi_transfer * xfer)1319 static int spi_transfer_wait(struct spi_controller *ctlr,
1320 struct spi_message *msg,
1321 struct spi_transfer *xfer)
1322 {
1323 struct spi_statistics __percpu *statm = ctlr->pcpu_statistics;
1324 struct spi_statistics __percpu *stats = msg->spi->pcpu_statistics;
1325 u32 speed_hz = xfer->speed_hz;
1326 unsigned long long ms;
1327
1328 if (spi_controller_is_slave(ctlr)) {
1329 if (wait_for_completion_interruptible(&ctlr->xfer_completion)) {
1330 dev_dbg(&msg->spi->dev, "SPI transfer interrupted\n");
1331 return -EINTR;
1332 }
1333 } else {
1334 if (!speed_hz)
1335 speed_hz = 100000;
1336
1337 /*
1338 * For each byte we wait for 8 cycles of the SPI clock.
1339 * Since speed is defined in Hz and we want milliseconds,
1340 * use respective multiplier, but before the division,
1341 * otherwise we may get 0 for short transfers.
1342 */
1343 ms = 8LL * MSEC_PER_SEC * xfer->len;
1344 do_div(ms, speed_hz);
1345
1346 /*
1347 * Increase it twice and add 200 ms tolerance, use
1348 * predefined maximum in case of overflow.
1349 */
1350 ms += ms + 200;
1351 if (ms > UINT_MAX)
1352 ms = UINT_MAX;
1353
1354 ms = wait_for_completion_timeout(&ctlr->xfer_completion,
1355 msecs_to_jiffies(ms));
1356
1357 if (ms == 0) {
1358 SPI_STATISTICS_INCREMENT_FIELD(statm, timedout);
1359 SPI_STATISTICS_INCREMENT_FIELD(stats, timedout);
1360 dev_err(&msg->spi->dev,
1361 "SPI transfer timed out\n");
1362 return -ETIMEDOUT;
1363 }
1364 }
1365
1366 return 0;
1367 }
1368
_spi_transfer_delay_ns(u32 ns)1369 static void _spi_transfer_delay_ns(u32 ns)
1370 {
1371 if (!ns)
1372 return;
1373 if (ns <= NSEC_PER_USEC) {
1374 ndelay(ns);
1375 } else {
1376 u32 us = DIV_ROUND_UP(ns, NSEC_PER_USEC);
1377
1378 if (us <= 10)
1379 udelay(us);
1380 else
1381 usleep_range(us, us + DIV_ROUND_UP(us, 10));
1382 }
1383 }
1384
spi_delay_to_ns(struct spi_delay * _delay,struct spi_transfer * xfer)1385 int spi_delay_to_ns(struct spi_delay *_delay, struct spi_transfer *xfer)
1386 {
1387 u32 delay = _delay->value;
1388 u32 unit = _delay->unit;
1389 u32 hz;
1390
1391 if (!delay)
1392 return 0;
1393
1394 switch (unit) {
1395 case SPI_DELAY_UNIT_USECS:
1396 delay *= NSEC_PER_USEC;
1397 break;
1398 case SPI_DELAY_UNIT_NSECS:
1399 /* Nothing to do here */
1400 break;
1401 case SPI_DELAY_UNIT_SCK:
1402 /* Clock cycles need to be obtained from spi_transfer */
1403 if (!xfer)
1404 return -EINVAL;
1405 /*
1406 * If there is unknown effective speed, approximate it
1407 * by underestimating with half of the requested Hz.
1408 */
1409 hz = xfer->effective_speed_hz ?: xfer->speed_hz / 2;
1410 if (!hz)
1411 return -EINVAL;
1412
1413 /* Convert delay to nanoseconds */
1414 delay *= DIV_ROUND_UP(NSEC_PER_SEC, hz);
1415 break;
1416 default:
1417 return -EINVAL;
1418 }
1419
1420 return delay;
1421 }
1422 EXPORT_SYMBOL_GPL(spi_delay_to_ns);
1423
spi_delay_exec(struct spi_delay * _delay,struct spi_transfer * xfer)1424 int spi_delay_exec(struct spi_delay *_delay, struct spi_transfer *xfer)
1425 {
1426 int delay;
1427
1428 might_sleep();
1429
1430 if (!_delay)
1431 return -EINVAL;
1432
1433 delay = spi_delay_to_ns(_delay, xfer);
1434 if (delay < 0)
1435 return delay;
1436
1437 _spi_transfer_delay_ns(delay);
1438
1439 return 0;
1440 }
1441 EXPORT_SYMBOL_GPL(spi_delay_exec);
1442
_spi_transfer_cs_change_delay(struct spi_message * msg,struct spi_transfer * xfer)1443 static void _spi_transfer_cs_change_delay(struct spi_message *msg,
1444 struct spi_transfer *xfer)
1445 {
1446 u32 default_delay_ns = 10 * NSEC_PER_USEC;
1447 u32 delay = xfer->cs_change_delay.value;
1448 u32 unit = xfer->cs_change_delay.unit;
1449 int ret;
1450
1451 /* Return early on "fast" mode - for everything but USECS */
1452 if (!delay) {
1453 if (unit == SPI_DELAY_UNIT_USECS)
1454 _spi_transfer_delay_ns(default_delay_ns);
1455 return;
1456 }
1457
1458 ret = spi_delay_exec(&xfer->cs_change_delay, xfer);
1459 if (ret) {
1460 dev_err_once(&msg->spi->dev,
1461 "Use of unsupported delay unit %i, using default of %luus\n",
1462 unit, default_delay_ns / NSEC_PER_USEC);
1463 _spi_transfer_delay_ns(default_delay_ns);
1464 }
1465 }
1466
spi_transfer_cs_change_delay_exec(struct spi_message * msg,struct spi_transfer * xfer)1467 void spi_transfer_cs_change_delay_exec(struct spi_message *msg,
1468 struct spi_transfer *xfer)
1469 {
1470 _spi_transfer_cs_change_delay(msg, xfer);
1471 }
1472 EXPORT_SYMBOL_GPL(spi_transfer_cs_change_delay_exec);
1473
1474 /*
1475 * spi_transfer_one_message - Default implementation of transfer_one_message()
1476 *
1477 * This is a standard implementation of transfer_one_message() for
1478 * drivers which implement a transfer_one() operation. It provides
1479 * standard handling of delays and chip select management.
1480 */
spi_transfer_one_message(struct spi_controller * ctlr,struct spi_message * msg)1481 static int spi_transfer_one_message(struct spi_controller *ctlr,
1482 struct spi_message *msg)
1483 {
1484 struct spi_transfer *xfer;
1485 bool keep_cs = false;
1486 int ret = 0;
1487 struct spi_statistics __percpu *statm = ctlr->pcpu_statistics;
1488 struct spi_statistics __percpu *stats = msg->spi->pcpu_statistics;
1489
1490 xfer = list_first_entry(&msg->transfers, struct spi_transfer, transfer_list);
1491 spi_set_cs(msg->spi, !xfer->cs_off, false);
1492
1493 SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
1494 SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
1495
1496 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1497 trace_spi_transfer_start(msg, xfer);
1498
1499 spi_statistics_add_transfer_stats(statm, xfer, ctlr);
1500 spi_statistics_add_transfer_stats(stats, xfer, ctlr);
1501
1502 if (!ctlr->ptp_sts_supported) {
1503 xfer->ptp_sts_word_pre = 0;
1504 ptp_read_system_prets(xfer->ptp_sts);
1505 }
1506
1507 if ((xfer->tx_buf || xfer->rx_buf) && xfer->len) {
1508 reinit_completion(&ctlr->xfer_completion);
1509
1510 fallback_pio:
1511 spi_dma_sync_for_device(ctlr, xfer);
1512 ret = ctlr->transfer_one(ctlr, msg->spi, xfer);
1513 if (ret < 0) {
1514 spi_dma_sync_for_cpu(ctlr, xfer);
1515
1516 if (ctlr->cur_msg_mapped &&
1517 (xfer->error & SPI_TRANS_FAIL_NO_START)) {
1518 __spi_unmap_msg(ctlr, msg);
1519 ctlr->fallback = true;
1520 xfer->error &= ~SPI_TRANS_FAIL_NO_START;
1521 goto fallback_pio;
1522 }
1523
1524 SPI_STATISTICS_INCREMENT_FIELD(statm,
1525 errors);
1526 SPI_STATISTICS_INCREMENT_FIELD(stats,
1527 errors);
1528 dev_err(&msg->spi->dev,
1529 "SPI transfer failed: %d\n", ret);
1530 goto out;
1531 }
1532
1533 if (ret > 0) {
1534 ret = spi_transfer_wait(ctlr, msg, xfer);
1535 if (ret < 0)
1536 msg->status = ret;
1537 }
1538
1539 spi_dma_sync_for_cpu(ctlr, xfer);
1540 } else {
1541 if (xfer->len)
1542 dev_err(&msg->spi->dev,
1543 "Bufferless transfer has length %u\n",
1544 xfer->len);
1545 }
1546
1547 if (!ctlr->ptp_sts_supported) {
1548 ptp_read_system_postts(xfer->ptp_sts);
1549 xfer->ptp_sts_word_post = xfer->len;
1550 }
1551
1552 trace_spi_transfer_stop(msg, xfer);
1553
1554 if (msg->status != -EINPROGRESS)
1555 goto out;
1556
1557 spi_transfer_delay_exec(xfer);
1558
1559 if (xfer->cs_change) {
1560 if (list_is_last(&xfer->transfer_list,
1561 &msg->transfers)) {
1562 keep_cs = true;
1563 } else {
1564 if (!xfer->cs_off)
1565 spi_set_cs(msg->spi, false, false);
1566 _spi_transfer_cs_change_delay(msg, xfer);
1567 if (!list_next_entry(xfer, transfer_list)->cs_off)
1568 spi_set_cs(msg->spi, true, false);
1569 }
1570 } else if (!list_is_last(&xfer->transfer_list, &msg->transfers) &&
1571 xfer->cs_off != list_next_entry(xfer, transfer_list)->cs_off) {
1572 spi_set_cs(msg->spi, xfer->cs_off, false);
1573 }
1574
1575 msg->actual_length += xfer->len;
1576 }
1577
1578 out:
1579 if (ret != 0 || !keep_cs)
1580 spi_set_cs(msg->spi, false, false);
1581
1582 if (msg->status == -EINPROGRESS)
1583 msg->status = ret;
1584
1585 if (msg->status && ctlr->handle_err)
1586 ctlr->handle_err(ctlr, msg);
1587
1588 spi_finalize_current_message(ctlr);
1589
1590 return ret;
1591 }
1592
1593 /**
1594 * spi_finalize_current_transfer - report completion of a transfer
1595 * @ctlr: the controller reporting completion
1596 *
1597 * Called by SPI drivers using the core transfer_one_message()
1598 * implementation to notify it that the current interrupt driven
1599 * transfer has finished and the next one may be scheduled.
1600 */
spi_finalize_current_transfer(struct spi_controller * ctlr)1601 void spi_finalize_current_transfer(struct spi_controller *ctlr)
1602 {
1603 complete(&ctlr->xfer_completion);
1604 }
1605 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1606
spi_idle_runtime_pm(struct spi_controller * ctlr)1607 static void spi_idle_runtime_pm(struct spi_controller *ctlr)
1608 {
1609 if (ctlr->auto_runtime_pm) {
1610 pm_runtime_mark_last_busy(ctlr->dev.parent);
1611 pm_runtime_put_autosuspend(ctlr->dev.parent);
1612 }
1613 }
1614
__spi_pump_transfer_message(struct spi_controller * ctlr,struct spi_message * msg,bool was_busy)1615 static int __spi_pump_transfer_message(struct spi_controller *ctlr,
1616 struct spi_message *msg, bool was_busy)
1617 {
1618 struct spi_transfer *xfer;
1619 int ret;
1620
1621 if (!was_busy && ctlr->auto_runtime_pm) {
1622 ret = pm_runtime_get_sync(ctlr->dev.parent);
1623 if (ret < 0) {
1624 pm_runtime_put_noidle(ctlr->dev.parent);
1625 dev_err(&ctlr->dev, "Failed to power device: %d\n",
1626 ret);
1627
1628 msg->status = ret;
1629 spi_finalize_current_message(ctlr);
1630
1631 return ret;
1632 }
1633 }
1634
1635 if (!was_busy)
1636 trace_spi_controller_busy(ctlr);
1637
1638 if (!was_busy && ctlr->prepare_transfer_hardware) {
1639 ret = ctlr->prepare_transfer_hardware(ctlr);
1640 if (ret) {
1641 dev_err(&ctlr->dev,
1642 "failed to prepare transfer hardware: %d\n",
1643 ret);
1644
1645 if (ctlr->auto_runtime_pm)
1646 pm_runtime_put(ctlr->dev.parent);
1647
1648 msg->status = ret;
1649 spi_finalize_current_message(ctlr);
1650
1651 return ret;
1652 }
1653 }
1654
1655 trace_spi_message_start(msg);
1656
1657 ret = spi_split_transfers_maxsize(ctlr, msg,
1658 spi_max_transfer_size(msg->spi),
1659 GFP_KERNEL | GFP_DMA);
1660 if (ret) {
1661 msg->status = ret;
1662 spi_finalize_current_message(ctlr);
1663 return ret;
1664 }
1665
1666 if (ctlr->prepare_message) {
1667 ret = ctlr->prepare_message(ctlr, msg);
1668 if (ret) {
1669 dev_err(&ctlr->dev, "failed to prepare message: %d\n",
1670 ret);
1671 msg->status = ret;
1672 spi_finalize_current_message(ctlr);
1673 return ret;
1674 }
1675 msg->prepared = true;
1676 }
1677
1678 ret = spi_map_msg(ctlr, msg);
1679 if (ret) {
1680 msg->status = ret;
1681 spi_finalize_current_message(ctlr);
1682 return ret;
1683 }
1684
1685 if (!ctlr->ptp_sts_supported && !ctlr->transfer_one) {
1686 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1687 xfer->ptp_sts_word_pre = 0;
1688 ptp_read_system_prets(xfer->ptp_sts);
1689 }
1690 }
1691
1692 /*
1693 * Drivers implementation of transfer_one_message() must arrange for
1694 * spi_finalize_current_message() to get called. Most drivers will do
1695 * this in the calling context, but some don't. For those cases, a
1696 * completion is used to guarantee that this function does not return
1697 * until spi_finalize_current_message() is done accessing
1698 * ctlr->cur_msg.
1699 * Use of the following two flags enable to opportunistically skip the
1700 * use of the completion since its use involves expensive spin locks.
1701 * In case of a race with the context that calls
1702 * spi_finalize_current_message() the completion will always be used,
1703 * due to strict ordering of these flags using barriers.
1704 */
1705 WRITE_ONCE(ctlr->cur_msg_incomplete, true);
1706 WRITE_ONCE(ctlr->cur_msg_need_completion, false);
1707 reinit_completion(&ctlr->cur_msg_completion);
1708 smp_wmb(); /* Make these available to spi_finalize_current_message() */
1709
1710 ret = ctlr->transfer_one_message(ctlr, msg);
1711 if (ret) {
1712 dev_err(&ctlr->dev,
1713 "failed to transfer one message from queue\n");
1714 return ret;
1715 }
1716
1717 WRITE_ONCE(ctlr->cur_msg_need_completion, true);
1718 smp_mb(); /* See spi_finalize_current_message()... */
1719 if (READ_ONCE(ctlr->cur_msg_incomplete))
1720 wait_for_completion(&ctlr->cur_msg_completion);
1721
1722 return 0;
1723 }
1724
1725 /**
1726 * __spi_pump_messages - function which processes SPI message queue
1727 * @ctlr: controller to process queue for
1728 * @in_kthread: true if we are in the context of the message pump thread
1729 *
1730 * This function checks if there is any SPI message in the queue that
1731 * needs processing and if so call out to the driver to initialize hardware
1732 * and transfer each message.
1733 *
1734 * Note that it is called both from the kthread itself and also from
1735 * inside spi_sync(); the queue extraction handling at the top of the
1736 * function should deal with this safely.
1737 */
__spi_pump_messages(struct spi_controller * ctlr,bool in_kthread)1738 static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread)
1739 {
1740 struct spi_message *msg;
1741 bool was_busy = false;
1742 unsigned long flags;
1743 int ret;
1744
1745 /* Take the I/O mutex */
1746 mutex_lock(&ctlr->io_mutex);
1747
1748 /* Lock queue */
1749 spin_lock_irqsave(&ctlr->queue_lock, flags);
1750
1751 /* Make sure we are not already running a message */
1752 if (ctlr->cur_msg)
1753 goto out_unlock;
1754
1755 /* Check if the queue is idle */
1756 if (list_empty(&ctlr->queue) || !ctlr->running) {
1757 if (!ctlr->busy)
1758 goto out_unlock;
1759
1760 /* Defer any non-atomic teardown to the thread */
1761 if (!in_kthread) {
1762 if (!ctlr->dummy_rx && !ctlr->dummy_tx &&
1763 !ctlr->unprepare_transfer_hardware) {
1764 spi_idle_runtime_pm(ctlr);
1765 ctlr->busy = false;
1766 ctlr->queue_empty = true;
1767 trace_spi_controller_idle(ctlr);
1768 } else {
1769 kthread_queue_work(ctlr->kworker,
1770 &ctlr->pump_messages);
1771 }
1772 goto out_unlock;
1773 }
1774
1775 ctlr->busy = false;
1776 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1777
1778 kfree(ctlr->dummy_rx);
1779 ctlr->dummy_rx = NULL;
1780 kfree(ctlr->dummy_tx);
1781 ctlr->dummy_tx = NULL;
1782 if (ctlr->unprepare_transfer_hardware &&
1783 ctlr->unprepare_transfer_hardware(ctlr))
1784 dev_err(&ctlr->dev,
1785 "failed to unprepare transfer hardware\n");
1786 spi_idle_runtime_pm(ctlr);
1787 trace_spi_controller_idle(ctlr);
1788
1789 spin_lock_irqsave(&ctlr->queue_lock, flags);
1790 ctlr->queue_empty = true;
1791 goto out_unlock;
1792 }
1793
1794 /* Extract head of queue */
1795 msg = list_first_entry(&ctlr->queue, struct spi_message, queue);
1796 ctlr->cur_msg = msg;
1797
1798 list_del_init(&msg->queue);
1799 if (ctlr->busy)
1800 was_busy = true;
1801 else
1802 ctlr->busy = true;
1803 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1804
1805 ret = __spi_pump_transfer_message(ctlr, msg, was_busy);
1806 kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
1807
1808 ctlr->cur_msg = NULL;
1809 ctlr->fallback = false;
1810
1811 mutex_unlock(&ctlr->io_mutex);
1812
1813 /* Prod the scheduler in case transfer_one() was busy waiting */
1814 if (!ret)
1815 cond_resched();
1816 return;
1817
1818 out_unlock:
1819 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1820 mutex_unlock(&ctlr->io_mutex);
1821 }
1822
1823 /**
1824 * spi_pump_messages - kthread work function which processes spi message queue
1825 * @work: pointer to kthread work struct contained in the controller struct
1826 */
spi_pump_messages(struct kthread_work * work)1827 static void spi_pump_messages(struct kthread_work *work)
1828 {
1829 struct spi_controller *ctlr =
1830 container_of(work, struct spi_controller, pump_messages);
1831
1832 __spi_pump_messages(ctlr, true);
1833 }
1834
1835 /**
1836 * spi_take_timestamp_pre - helper to collect the beginning of the TX timestamp
1837 * @ctlr: Pointer to the spi_controller structure of the driver
1838 * @xfer: Pointer to the transfer being timestamped
1839 * @progress: How many words (not bytes) have been transferred so far
1840 * @irqs_off: If true, will disable IRQs and preemption for the duration of the
1841 * transfer, for less jitter in time measurement. Only compatible
1842 * with PIO drivers. If true, must follow up with
1843 * spi_take_timestamp_post or otherwise system will crash.
1844 * WARNING: for fully predictable results, the CPU frequency must
1845 * also be under control (governor).
1846 *
1847 * This is a helper for drivers to collect the beginning of the TX timestamp
1848 * for the requested byte from the SPI transfer. The frequency with which this
1849 * function must be called (once per word, once for the whole transfer, once
1850 * per batch of words etc) is arbitrary as long as the @tx buffer offset is
1851 * greater than or equal to the requested byte at the time of the call. The
1852 * timestamp is only taken once, at the first such call. It is assumed that
1853 * the driver advances its @tx buffer pointer monotonically.
1854 */
spi_take_timestamp_pre(struct spi_controller * ctlr,struct spi_transfer * xfer,size_t progress,bool irqs_off)1855 void spi_take_timestamp_pre(struct spi_controller *ctlr,
1856 struct spi_transfer *xfer,
1857 size_t progress, bool irqs_off)
1858 {
1859 if (!xfer->ptp_sts)
1860 return;
1861
1862 if (xfer->timestamped)
1863 return;
1864
1865 if (progress > xfer->ptp_sts_word_pre)
1866 return;
1867
1868 /* Capture the resolution of the timestamp */
1869 xfer->ptp_sts_word_pre = progress;
1870
1871 if (irqs_off) {
1872 local_irq_save(ctlr->irq_flags);
1873 preempt_disable();
1874 }
1875
1876 ptp_read_system_prets(xfer->ptp_sts);
1877 }
1878 EXPORT_SYMBOL_GPL(spi_take_timestamp_pre);
1879
1880 /**
1881 * spi_take_timestamp_post - helper to collect the end of the TX timestamp
1882 * @ctlr: Pointer to the spi_controller structure of the driver
1883 * @xfer: Pointer to the transfer being timestamped
1884 * @progress: How many words (not bytes) have been transferred so far
1885 * @irqs_off: If true, will re-enable IRQs and preemption for the local CPU.
1886 *
1887 * This is a helper for drivers to collect the end of the TX timestamp for
1888 * the requested byte from the SPI transfer. Can be called with an arbitrary
1889 * frequency: only the first call where @tx exceeds or is equal to the
1890 * requested word will be timestamped.
1891 */
spi_take_timestamp_post(struct spi_controller * ctlr,struct spi_transfer * xfer,size_t progress,bool irqs_off)1892 void spi_take_timestamp_post(struct spi_controller *ctlr,
1893 struct spi_transfer *xfer,
1894 size_t progress, bool irqs_off)
1895 {
1896 if (!xfer->ptp_sts)
1897 return;
1898
1899 if (xfer->timestamped)
1900 return;
1901
1902 if (progress < xfer->ptp_sts_word_post)
1903 return;
1904
1905 ptp_read_system_postts(xfer->ptp_sts);
1906
1907 if (irqs_off) {
1908 local_irq_restore(ctlr->irq_flags);
1909 preempt_enable();
1910 }
1911
1912 /* Capture the resolution of the timestamp */
1913 xfer->ptp_sts_word_post = progress;
1914
1915 xfer->timestamped = 1;
1916 }
1917 EXPORT_SYMBOL_GPL(spi_take_timestamp_post);
1918
1919 /**
1920 * spi_set_thread_rt - set the controller to pump at realtime priority
1921 * @ctlr: controller to boost priority of
1922 *
1923 * This can be called because the controller requested realtime priority
1924 * (by setting the ->rt value before calling spi_register_controller()) or
1925 * because a device on the bus said that its transfers needed realtime
1926 * priority.
1927 *
1928 * NOTE: at the moment if any device on a bus says it needs realtime then
1929 * the thread will be at realtime priority for all transfers on that
1930 * controller. If this eventually becomes a problem we may see if we can
1931 * find a way to boost the priority only temporarily during relevant
1932 * transfers.
1933 */
spi_set_thread_rt(struct spi_controller * ctlr)1934 static void spi_set_thread_rt(struct spi_controller *ctlr)
1935 {
1936 dev_info(&ctlr->dev,
1937 "will run message pump with realtime priority\n");
1938 sched_set_fifo(ctlr->kworker->task);
1939 }
1940
spi_init_queue(struct spi_controller * ctlr)1941 static int spi_init_queue(struct spi_controller *ctlr)
1942 {
1943 ctlr->running = false;
1944 ctlr->busy = false;
1945 ctlr->queue_empty = true;
1946
1947 ctlr->kworker = kthread_create_worker(0, dev_name(&ctlr->dev));
1948 if (IS_ERR(ctlr->kworker)) {
1949 dev_err(&ctlr->dev, "failed to create message pump kworker\n");
1950 return PTR_ERR(ctlr->kworker);
1951 }
1952
1953 kthread_init_work(&ctlr->pump_messages, spi_pump_messages);
1954
1955 /*
1956 * Controller config will indicate if this controller should run the
1957 * message pump with high (realtime) priority to reduce the transfer
1958 * latency on the bus by minimising the delay between a transfer
1959 * request and the scheduling of the message pump thread. Without this
1960 * setting the message pump thread will remain at default priority.
1961 */
1962 if (ctlr->rt)
1963 spi_set_thread_rt(ctlr);
1964
1965 return 0;
1966 }
1967
1968 /**
1969 * spi_get_next_queued_message() - called by driver to check for queued
1970 * messages
1971 * @ctlr: the controller to check for queued messages
1972 *
1973 * If there are more messages in the queue, the next message is returned from
1974 * this call.
1975 *
1976 * Return: the next message in the queue, else NULL if the queue is empty.
1977 */
spi_get_next_queued_message(struct spi_controller * ctlr)1978 struct spi_message *spi_get_next_queued_message(struct spi_controller *ctlr)
1979 {
1980 struct spi_message *next;
1981 unsigned long flags;
1982
1983 /* Get a pointer to the next message, if any */
1984 spin_lock_irqsave(&ctlr->queue_lock, flags);
1985 next = list_first_entry_or_null(&ctlr->queue, struct spi_message,
1986 queue);
1987 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1988
1989 return next;
1990 }
1991 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1992
1993 /**
1994 * spi_finalize_current_message() - the current message is complete
1995 * @ctlr: the controller to return the message to
1996 *
1997 * Called by the driver to notify the core that the message in the front of the
1998 * queue is complete and can be removed from the queue.
1999 */
spi_finalize_current_message(struct spi_controller * ctlr)2000 void spi_finalize_current_message(struct spi_controller *ctlr)
2001 {
2002 struct spi_transfer *xfer;
2003 struct spi_message *mesg;
2004 int ret;
2005
2006 mesg = ctlr->cur_msg;
2007
2008 if (!ctlr->ptp_sts_supported && !ctlr->transfer_one) {
2009 list_for_each_entry(xfer, &mesg->transfers, transfer_list) {
2010 ptp_read_system_postts(xfer->ptp_sts);
2011 xfer->ptp_sts_word_post = xfer->len;
2012 }
2013 }
2014
2015 if (unlikely(ctlr->ptp_sts_supported))
2016 list_for_each_entry(xfer, &mesg->transfers, transfer_list)
2017 WARN_ON_ONCE(xfer->ptp_sts && !xfer->timestamped);
2018
2019 spi_unmap_msg(ctlr, mesg);
2020
2021 /*
2022 * In the prepare_messages callback the SPI bus has the opportunity
2023 * to split a transfer to smaller chunks.
2024 *
2025 * Release the split transfers here since spi_map_msg() is done on
2026 * the split transfers.
2027 */
2028 spi_res_release(ctlr, mesg);
2029
2030 if (mesg->prepared && ctlr->unprepare_message) {
2031 ret = ctlr->unprepare_message(ctlr, mesg);
2032 if (ret) {
2033 dev_err(&ctlr->dev, "failed to unprepare message: %d\n",
2034 ret);
2035 }
2036 }
2037
2038 mesg->prepared = false;
2039
2040 WRITE_ONCE(ctlr->cur_msg_incomplete, false);
2041 smp_mb(); /* See __spi_pump_transfer_message()... */
2042 if (READ_ONCE(ctlr->cur_msg_need_completion))
2043 complete(&ctlr->cur_msg_completion);
2044
2045 trace_spi_message_done(mesg);
2046
2047 mesg->state = NULL;
2048 if (mesg->complete)
2049 mesg->complete(mesg->context);
2050 }
2051 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
2052
spi_start_queue(struct spi_controller * ctlr)2053 static int spi_start_queue(struct spi_controller *ctlr)
2054 {
2055 unsigned long flags;
2056
2057 spin_lock_irqsave(&ctlr->queue_lock, flags);
2058
2059 if (ctlr->running || ctlr->busy) {
2060 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
2061 return -EBUSY;
2062 }
2063
2064 ctlr->running = true;
2065 ctlr->cur_msg = NULL;
2066 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
2067
2068 kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
2069
2070 return 0;
2071 }
2072
spi_stop_queue(struct spi_controller * ctlr)2073 static int spi_stop_queue(struct spi_controller *ctlr)
2074 {
2075 unsigned long flags;
2076 unsigned limit = 500;
2077 int ret = 0;
2078
2079 spin_lock_irqsave(&ctlr->queue_lock, flags);
2080
2081 /*
2082 * This is a bit lame, but is optimized for the common execution path.
2083 * A wait_queue on the ctlr->busy could be used, but then the common
2084 * execution path (pump_messages) would be required to call wake_up or
2085 * friends on every SPI message. Do this instead.
2086 */
2087 while ((!list_empty(&ctlr->queue) || ctlr->busy) && limit--) {
2088 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
2089 usleep_range(10000, 11000);
2090 spin_lock_irqsave(&ctlr->queue_lock, flags);
2091 }
2092
2093 if (!list_empty(&ctlr->queue) || ctlr->busy)
2094 ret = -EBUSY;
2095 else
2096 ctlr->running = false;
2097
2098 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
2099
2100 if (ret) {
2101 dev_warn(&ctlr->dev, "could not stop message queue\n");
2102 return ret;
2103 }
2104 return ret;
2105 }
2106
spi_destroy_queue(struct spi_controller * ctlr)2107 static int spi_destroy_queue(struct spi_controller *ctlr)
2108 {
2109 int ret;
2110
2111 ret = spi_stop_queue(ctlr);
2112
2113 /*
2114 * kthread_flush_worker will block until all work is done.
2115 * If the reason that stop_queue timed out is that the work will never
2116 * finish, then it does no good to call flush/stop thread, so
2117 * return anyway.
2118 */
2119 if (ret) {
2120 dev_err(&ctlr->dev, "problem destroying queue\n");
2121 return ret;
2122 }
2123
2124 kthread_destroy_worker(ctlr->kworker);
2125
2126 return 0;
2127 }
2128
__spi_queued_transfer(struct spi_device * spi,struct spi_message * msg,bool need_pump)2129 static int __spi_queued_transfer(struct spi_device *spi,
2130 struct spi_message *msg,
2131 bool need_pump)
2132 {
2133 struct spi_controller *ctlr = spi->controller;
2134 unsigned long flags;
2135
2136 spin_lock_irqsave(&ctlr->queue_lock, flags);
2137
2138 if (!ctlr->running) {
2139 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
2140 return -ESHUTDOWN;
2141 }
2142 msg->actual_length = 0;
2143 msg->status = -EINPROGRESS;
2144
2145 list_add_tail(&msg->queue, &ctlr->queue);
2146 ctlr->queue_empty = false;
2147 if (!ctlr->busy && need_pump)
2148 kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
2149
2150 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
2151 return 0;
2152 }
2153
2154 /**
2155 * spi_queued_transfer - transfer function for queued transfers
2156 * @spi: SPI device which is requesting transfer
2157 * @msg: SPI message which is to handled is queued to driver queue
2158 *
2159 * Return: zero on success, else a negative error code.
2160 */
spi_queued_transfer(struct spi_device * spi,struct spi_message * msg)2161 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
2162 {
2163 return __spi_queued_transfer(spi, msg, true);
2164 }
2165
spi_controller_initialize_queue(struct spi_controller * ctlr)2166 static int spi_controller_initialize_queue(struct spi_controller *ctlr)
2167 {
2168 int ret;
2169
2170 ctlr->transfer = spi_queued_transfer;
2171 if (!ctlr->transfer_one_message)
2172 ctlr->transfer_one_message = spi_transfer_one_message;
2173
2174 /* Initialize and start queue */
2175 ret = spi_init_queue(ctlr);
2176 if (ret) {
2177 dev_err(&ctlr->dev, "problem initializing queue\n");
2178 goto err_init_queue;
2179 }
2180 ctlr->queued = true;
2181 ret = spi_start_queue(ctlr);
2182 if (ret) {
2183 dev_err(&ctlr->dev, "problem starting queue\n");
2184 goto err_start_queue;
2185 }
2186
2187 return 0;
2188
2189 err_start_queue:
2190 spi_destroy_queue(ctlr);
2191 err_init_queue:
2192 return ret;
2193 }
2194
2195 /**
2196 * spi_flush_queue - Send all pending messages in the queue from the callers'
2197 * context
2198 * @ctlr: controller to process queue for
2199 *
2200 * This should be used when one wants to ensure all pending messages have been
2201 * sent before doing something. Is used by the spi-mem code to make sure SPI
2202 * memory operations do not preempt regular SPI transfers that have been queued
2203 * before the spi-mem operation.
2204 */
spi_flush_queue(struct spi_controller * ctlr)2205 void spi_flush_queue(struct spi_controller *ctlr)
2206 {
2207 if (ctlr->transfer == spi_queued_transfer)
2208 __spi_pump_messages(ctlr, false);
2209 }
2210
2211 /*-------------------------------------------------------------------------*/
2212
2213 #if defined(CONFIG_OF)
of_spi_parse_dt_cs_delay(struct device_node * nc,struct spi_delay * delay,const char * prop)2214 static void of_spi_parse_dt_cs_delay(struct device_node *nc,
2215 struct spi_delay *delay, const char *prop)
2216 {
2217 u32 value;
2218
2219 if (!of_property_read_u32(nc, prop, &value)) {
2220 if (value > U16_MAX) {
2221 delay->value = DIV_ROUND_UP(value, 1000);
2222 delay->unit = SPI_DELAY_UNIT_USECS;
2223 } else {
2224 delay->value = value;
2225 delay->unit = SPI_DELAY_UNIT_NSECS;
2226 }
2227 }
2228 }
2229
of_spi_parse_dt(struct spi_controller * ctlr,struct spi_device * spi,struct device_node * nc)2230 static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi,
2231 struct device_node *nc)
2232 {
2233 u32 value;
2234 int rc;
2235
2236 /* Mode (clock phase/polarity/etc.) */
2237 if (of_property_read_bool(nc, "spi-cpha"))
2238 spi->mode |= SPI_CPHA;
2239 if (of_property_read_bool(nc, "spi-cpol"))
2240 spi->mode |= SPI_CPOL;
2241 if (of_property_read_bool(nc, "spi-3wire"))
2242 spi->mode |= SPI_3WIRE;
2243 if (of_property_read_bool(nc, "spi-lsb-first"))
2244 spi->mode |= SPI_LSB_FIRST;
2245 if (of_property_read_bool(nc, "spi-cs-high"))
2246 spi->mode |= SPI_CS_HIGH;
2247
2248 /* Device DUAL/QUAD mode */
2249 if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
2250 switch (value) {
2251 case 0:
2252 spi->mode |= SPI_NO_TX;
2253 break;
2254 case 1:
2255 break;
2256 case 2:
2257 spi->mode |= SPI_TX_DUAL;
2258 break;
2259 case 4:
2260 spi->mode |= SPI_TX_QUAD;
2261 break;
2262 case 8:
2263 spi->mode |= SPI_TX_OCTAL;
2264 break;
2265 default:
2266 dev_warn(&ctlr->dev,
2267 "spi-tx-bus-width %d not supported\n",
2268 value);
2269 break;
2270 }
2271 }
2272
2273 if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
2274 switch (value) {
2275 case 0:
2276 spi->mode |= SPI_NO_RX;
2277 break;
2278 case 1:
2279 break;
2280 case 2:
2281 spi->mode |= SPI_RX_DUAL;
2282 break;
2283 case 4:
2284 spi->mode |= SPI_RX_QUAD;
2285 break;
2286 case 8:
2287 spi->mode |= SPI_RX_OCTAL;
2288 break;
2289 default:
2290 dev_warn(&ctlr->dev,
2291 "spi-rx-bus-width %d not supported\n",
2292 value);
2293 break;
2294 }
2295 }
2296
2297 if (spi_controller_is_slave(ctlr)) {
2298 if (!of_node_name_eq(nc, "slave")) {
2299 dev_err(&ctlr->dev, "%pOF is not called 'slave'\n",
2300 nc);
2301 return -EINVAL;
2302 }
2303 return 0;
2304 }
2305
2306 /* Device address */
2307 rc = of_property_read_u32(nc, "reg", &value);
2308 if (rc) {
2309 dev_err(&ctlr->dev, "%pOF has no valid 'reg' property (%d)\n",
2310 nc, rc);
2311 return rc;
2312 }
2313 spi_set_chipselect(spi, 0, value);
2314
2315 /* Device speed */
2316 if (!of_property_read_u32(nc, "spi-max-frequency", &value))
2317 spi->max_speed_hz = value;
2318
2319 /* Device CS delays */
2320 of_spi_parse_dt_cs_delay(nc, &spi->cs_setup, "spi-cs-setup-delay-ns");
2321 of_spi_parse_dt_cs_delay(nc, &spi->cs_hold, "spi-cs-hold-delay-ns");
2322 of_spi_parse_dt_cs_delay(nc, &spi->cs_inactive, "spi-cs-inactive-delay-ns");
2323
2324 return 0;
2325 }
2326
2327 static struct spi_device *
of_register_spi_device(struct spi_controller * ctlr,struct device_node * nc)2328 of_register_spi_device(struct spi_controller *ctlr, struct device_node *nc)
2329 {
2330 struct spi_device *spi;
2331 int rc;
2332
2333 /* Alloc an spi_device */
2334 spi = spi_alloc_device(ctlr);
2335 if (!spi) {
2336 dev_err(&ctlr->dev, "spi_device alloc error for %pOF\n", nc);
2337 rc = -ENOMEM;
2338 goto err_out;
2339 }
2340
2341 /* Select device driver */
2342 rc = of_alias_from_compatible(nc, spi->modalias,
2343 sizeof(spi->modalias));
2344 if (rc < 0) {
2345 dev_err(&ctlr->dev, "cannot find modalias for %pOF\n", nc);
2346 goto err_out;
2347 }
2348
2349 rc = of_spi_parse_dt(ctlr, spi, nc);
2350 if (rc)
2351 goto err_out;
2352
2353 /* Store a pointer to the node in the device structure */
2354 of_node_get(nc);
2355
2356 device_set_node(&spi->dev, of_fwnode_handle(nc));
2357
2358 /* Register the new device */
2359 rc = spi_add_device(spi);
2360 if (rc) {
2361 dev_err(&ctlr->dev, "spi_device register error %pOF\n", nc);
2362 goto err_of_node_put;
2363 }
2364
2365 return spi;
2366
2367 err_of_node_put:
2368 of_node_put(nc);
2369 err_out:
2370 spi_dev_put(spi);
2371 return ERR_PTR(rc);
2372 }
2373
2374 /**
2375 * of_register_spi_devices() - Register child devices onto the SPI bus
2376 * @ctlr: Pointer to spi_controller device
2377 *
2378 * Registers an spi_device for each child node of controller node which
2379 * represents a valid SPI slave.
2380 */
of_register_spi_devices(struct spi_controller * ctlr)2381 static void of_register_spi_devices(struct spi_controller *ctlr)
2382 {
2383 struct spi_device *spi;
2384 struct device_node *nc;
2385
2386 for_each_available_child_of_node(ctlr->dev.of_node, nc) {
2387 if (of_node_test_and_set_flag(nc, OF_POPULATED))
2388 continue;
2389 spi = of_register_spi_device(ctlr, nc);
2390 if (IS_ERR(spi)) {
2391 dev_warn(&ctlr->dev,
2392 "Failed to create SPI device for %pOF\n", nc);
2393 of_node_clear_flag(nc, OF_POPULATED);
2394 }
2395 }
2396 }
2397 #else
of_register_spi_devices(struct spi_controller * ctlr)2398 static void of_register_spi_devices(struct spi_controller *ctlr) { }
2399 #endif
2400
2401 /**
2402 * spi_new_ancillary_device() - Register ancillary SPI device
2403 * @spi: Pointer to the main SPI device registering the ancillary device
2404 * @chip_select: Chip Select of the ancillary device
2405 *
2406 * Register an ancillary SPI device; for example some chips have a chip-select
2407 * for normal device usage and another one for setup/firmware upload.
2408 *
2409 * This may only be called from main SPI device's probe routine.
2410 *
2411 * Return: 0 on success; negative errno on failure
2412 */
spi_new_ancillary_device(struct spi_device * spi,u8 chip_select)2413 struct spi_device *spi_new_ancillary_device(struct spi_device *spi,
2414 u8 chip_select)
2415 {
2416 struct spi_controller *ctlr = spi->controller;
2417 struct spi_device *ancillary;
2418 int rc = 0;
2419
2420 /* Alloc an spi_device */
2421 ancillary = spi_alloc_device(ctlr);
2422 if (!ancillary) {
2423 rc = -ENOMEM;
2424 goto err_out;
2425 }
2426
2427 strscpy(ancillary->modalias, "dummy", sizeof(ancillary->modalias));
2428
2429 /* Use provided chip-select for ancillary device */
2430 spi_set_chipselect(ancillary, 0, chip_select);
2431
2432 /* Take over SPI mode/speed from SPI main device */
2433 ancillary->max_speed_hz = spi->max_speed_hz;
2434 ancillary->mode = spi->mode;
2435
2436 WARN_ON(!mutex_is_locked(&ctlr->add_lock));
2437
2438 /* Register the new device */
2439 rc = __spi_add_device(ancillary);
2440 if (rc) {
2441 dev_err(&spi->dev, "failed to register ancillary device\n");
2442 goto err_out;
2443 }
2444
2445 return ancillary;
2446
2447 err_out:
2448 spi_dev_put(ancillary);
2449 return ERR_PTR(rc);
2450 }
2451 EXPORT_SYMBOL_GPL(spi_new_ancillary_device);
2452
2453 #ifdef CONFIG_ACPI
2454 struct acpi_spi_lookup {
2455 struct spi_controller *ctlr;
2456 u32 max_speed_hz;
2457 u32 mode;
2458 int irq;
2459 u8 bits_per_word;
2460 u8 chip_select;
2461 int n;
2462 int index;
2463 };
2464
acpi_spi_count(struct acpi_resource * ares,void * data)2465 static int acpi_spi_count(struct acpi_resource *ares, void *data)
2466 {
2467 struct acpi_resource_spi_serialbus *sb;
2468 int *count = data;
2469
2470 if (ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
2471 return 1;
2472
2473 sb = &ares->data.spi_serial_bus;
2474 if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_SPI)
2475 return 1;
2476
2477 *count = *count + 1;
2478
2479 return 1;
2480 }
2481
2482 /**
2483 * acpi_spi_count_resources - Count the number of SpiSerialBus resources
2484 * @adev: ACPI device
2485 *
2486 * Return: the number of SpiSerialBus resources in the ACPI-device's
2487 * resource-list; or a negative error code.
2488 */
acpi_spi_count_resources(struct acpi_device * adev)2489 int acpi_spi_count_resources(struct acpi_device *adev)
2490 {
2491 LIST_HEAD(r);
2492 int count = 0;
2493 int ret;
2494
2495 ret = acpi_dev_get_resources(adev, &r, acpi_spi_count, &count);
2496 if (ret < 0)
2497 return ret;
2498
2499 acpi_dev_free_resource_list(&r);
2500
2501 return count;
2502 }
2503 EXPORT_SYMBOL_GPL(acpi_spi_count_resources);
2504
acpi_spi_parse_apple_properties(struct acpi_device * dev,struct acpi_spi_lookup * lookup)2505 static void acpi_spi_parse_apple_properties(struct acpi_device *dev,
2506 struct acpi_spi_lookup *lookup)
2507 {
2508 const union acpi_object *obj;
2509
2510 if (!x86_apple_machine)
2511 return;
2512
2513 if (!acpi_dev_get_property(dev, "spiSclkPeriod", ACPI_TYPE_BUFFER, &obj)
2514 && obj->buffer.length >= 4)
2515 lookup->max_speed_hz = NSEC_PER_SEC / *(u32 *)obj->buffer.pointer;
2516
2517 if (!acpi_dev_get_property(dev, "spiWordSize", ACPI_TYPE_BUFFER, &obj)
2518 && obj->buffer.length == 8)
2519 lookup->bits_per_word = *(u64 *)obj->buffer.pointer;
2520
2521 if (!acpi_dev_get_property(dev, "spiBitOrder", ACPI_TYPE_BUFFER, &obj)
2522 && obj->buffer.length == 8 && !*(u64 *)obj->buffer.pointer)
2523 lookup->mode |= SPI_LSB_FIRST;
2524
2525 if (!acpi_dev_get_property(dev, "spiSPO", ACPI_TYPE_BUFFER, &obj)
2526 && obj->buffer.length == 8 && *(u64 *)obj->buffer.pointer)
2527 lookup->mode |= SPI_CPOL;
2528
2529 if (!acpi_dev_get_property(dev, "spiSPH", ACPI_TYPE_BUFFER, &obj)
2530 && obj->buffer.length == 8 && *(u64 *)obj->buffer.pointer)
2531 lookup->mode |= SPI_CPHA;
2532 }
2533
2534 static struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev);
2535
acpi_spi_add_resource(struct acpi_resource * ares,void * data)2536 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
2537 {
2538 struct acpi_spi_lookup *lookup = data;
2539 struct spi_controller *ctlr = lookup->ctlr;
2540
2541 if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
2542 struct acpi_resource_spi_serialbus *sb;
2543 acpi_handle parent_handle;
2544 acpi_status status;
2545
2546 sb = &ares->data.spi_serial_bus;
2547 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
2548
2549 if (lookup->index != -1 && lookup->n++ != lookup->index)
2550 return 1;
2551
2552 status = acpi_get_handle(NULL,
2553 sb->resource_source.string_ptr,
2554 &parent_handle);
2555
2556 if (ACPI_FAILURE(status))
2557 return -ENODEV;
2558
2559 if (ctlr) {
2560 if (ACPI_HANDLE(ctlr->dev.parent) != parent_handle)
2561 return -ENODEV;
2562 } else {
2563 struct acpi_device *adev;
2564
2565 adev = acpi_fetch_acpi_dev(parent_handle);
2566 if (!adev)
2567 return -ENODEV;
2568
2569 ctlr = acpi_spi_find_controller_by_adev(adev);
2570 if (!ctlr)
2571 return -EPROBE_DEFER;
2572
2573 lookup->ctlr = ctlr;
2574 }
2575
2576 /*
2577 * ACPI DeviceSelection numbering is handled by the
2578 * host controller driver in Windows and can vary
2579 * from driver to driver. In Linux we always expect
2580 * 0 .. max - 1 so we need to ask the driver to
2581 * translate between the two schemes.
2582 */
2583 if (ctlr->fw_translate_cs) {
2584 int cs = ctlr->fw_translate_cs(ctlr,
2585 sb->device_selection);
2586 if (cs < 0)
2587 return cs;
2588 lookup->chip_select = cs;
2589 } else {
2590 lookup->chip_select = sb->device_selection;
2591 }
2592
2593 lookup->max_speed_hz = sb->connection_speed;
2594 lookup->bits_per_word = sb->data_bit_length;
2595
2596 if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
2597 lookup->mode |= SPI_CPHA;
2598 if (sb->clock_polarity == ACPI_SPI_START_HIGH)
2599 lookup->mode |= SPI_CPOL;
2600 if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
2601 lookup->mode |= SPI_CS_HIGH;
2602 }
2603 } else if (lookup->irq < 0) {
2604 struct resource r;
2605
2606 if (acpi_dev_resource_interrupt(ares, 0, &r))
2607 lookup->irq = r.start;
2608 }
2609
2610 /* Always tell the ACPI core to skip this resource */
2611 return 1;
2612 }
2613
2614 /**
2615 * acpi_spi_device_alloc - Allocate a spi device, and fill it in with ACPI information
2616 * @ctlr: controller to which the spi device belongs
2617 * @adev: ACPI Device for the spi device
2618 * @index: Index of the spi resource inside the ACPI Node
2619 *
2620 * This should be used to allocate a new SPI device from and ACPI Device node.
2621 * The caller is responsible for calling spi_add_device to register the SPI device.
2622 *
2623 * If ctlr is set to NULL, the Controller for the SPI device will be looked up
2624 * using the resource.
2625 * If index is set to -1, index is not used.
2626 * Note: If index is -1, ctlr must be set.
2627 *
2628 * Return: a pointer to the new device, or ERR_PTR on error.
2629 */
acpi_spi_device_alloc(struct spi_controller * ctlr,struct acpi_device * adev,int index)2630 struct spi_device *acpi_spi_device_alloc(struct spi_controller *ctlr,
2631 struct acpi_device *adev,
2632 int index)
2633 {
2634 acpi_handle parent_handle = NULL;
2635 struct list_head resource_list;
2636 struct acpi_spi_lookup lookup = {};
2637 struct spi_device *spi;
2638 int ret;
2639
2640 if (!ctlr && index == -1)
2641 return ERR_PTR(-EINVAL);
2642
2643 lookup.ctlr = ctlr;
2644 lookup.irq = -1;
2645 lookup.index = index;
2646 lookup.n = 0;
2647
2648 INIT_LIST_HEAD(&resource_list);
2649 ret = acpi_dev_get_resources(adev, &resource_list,
2650 acpi_spi_add_resource, &lookup);
2651 acpi_dev_free_resource_list(&resource_list);
2652
2653 if (ret < 0)
2654 /* Found SPI in _CRS but it points to another controller */
2655 return ERR_PTR(ret);
2656
2657 if (!lookup.max_speed_hz &&
2658 ACPI_SUCCESS(acpi_get_parent(adev->handle, &parent_handle)) &&
2659 ACPI_HANDLE(lookup.ctlr->dev.parent) == parent_handle) {
2660 /* Apple does not use _CRS but nested devices for SPI slaves */
2661 acpi_spi_parse_apple_properties(adev, &lookup);
2662 }
2663
2664 if (!lookup.max_speed_hz)
2665 return ERR_PTR(-ENODEV);
2666
2667 spi = spi_alloc_device(lookup.ctlr);
2668 if (!spi) {
2669 dev_err(&lookup.ctlr->dev, "failed to allocate SPI device for %s\n",
2670 dev_name(&adev->dev));
2671 return ERR_PTR(-ENOMEM);
2672 }
2673
2674 ACPI_COMPANION_SET(&spi->dev, adev);
2675 spi->max_speed_hz = lookup.max_speed_hz;
2676 spi->mode |= lookup.mode;
2677 spi->irq = lookup.irq;
2678 spi->bits_per_word = lookup.bits_per_word;
2679 spi_set_chipselect(spi, 0, lookup.chip_select);
2680
2681 return spi;
2682 }
2683 EXPORT_SYMBOL_GPL(acpi_spi_device_alloc);
2684
acpi_register_spi_device(struct spi_controller * ctlr,struct acpi_device * adev)2685 static acpi_status acpi_register_spi_device(struct spi_controller *ctlr,
2686 struct acpi_device *adev)
2687 {
2688 struct spi_device *spi;
2689
2690 if (acpi_bus_get_status(adev) || !adev->status.present ||
2691 acpi_device_enumerated(adev))
2692 return AE_OK;
2693
2694 spi = acpi_spi_device_alloc(ctlr, adev, -1);
2695 if (IS_ERR(spi)) {
2696 if (PTR_ERR(spi) == -ENOMEM)
2697 return AE_NO_MEMORY;
2698 else
2699 return AE_OK;
2700 }
2701
2702 acpi_set_modalias(adev, acpi_device_hid(adev), spi->modalias,
2703 sizeof(spi->modalias));
2704
2705 if (spi->irq < 0)
2706 spi->irq = acpi_dev_gpio_irq_get(adev, 0);
2707
2708 acpi_device_set_enumerated(adev);
2709
2710 adev->power.flags.ignore_parent = true;
2711 if (spi_add_device(spi)) {
2712 adev->power.flags.ignore_parent = false;
2713 dev_err(&ctlr->dev, "failed to add SPI device %s from ACPI\n",
2714 dev_name(&adev->dev));
2715 spi_dev_put(spi);
2716 }
2717
2718 return AE_OK;
2719 }
2720
acpi_spi_add_device(acpi_handle handle,u32 level,void * data,void ** return_value)2721 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
2722 void *data, void **return_value)
2723 {
2724 struct acpi_device *adev = acpi_fetch_acpi_dev(handle);
2725 struct spi_controller *ctlr = data;
2726
2727 if (!adev)
2728 return AE_OK;
2729
2730 return acpi_register_spi_device(ctlr, adev);
2731 }
2732
2733 #define SPI_ACPI_ENUMERATE_MAX_DEPTH 32
2734
acpi_register_spi_devices(struct spi_controller * ctlr)2735 static void acpi_register_spi_devices(struct spi_controller *ctlr)
2736 {
2737 acpi_status status;
2738 acpi_handle handle;
2739
2740 handle = ACPI_HANDLE(ctlr->dev.parent);
2741 if (!handle)
2742 return;
2743
2744 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
2745 SPI_ACPI_ENUMERATE_MAX_DEPTH,
2746 acpi_spi_add_device, NULL, ctlr, NULL);
2747 if (ACPI_FAILURE(status))
2748 dev_warn(&ctlr->dev, "failed to enumerate SPI slaves\n");
2749 }
2750 #else
acpi_register_spi_devices(struct spi_controller * ctlr)2751 static inline void acpi_register_spi_devices(struct spi_controller *ctlr) {}
2752 #endif /* CONFIG_ACPI */
2753
spi_controller_release(struct device * dev)2754 static void spi_controller_release(struct device *dev)
2755 {
2756 struct spi_controller *ctlr;
2757
2758 ctlr = container_of(dev, struct spi_controller, dev);
2759 kfree(ctlr);
2760 }
2761
2762 static struct class spi_master_class = {
2763 .name = "spi_master",
2764 .dev_release = spi_controller_release,
2765 .dev_groups = spi_master_groups,
2766 };
2767
2768 #ifdef CONFIG_SPI_SLAVE
2769 /**
2770 * spi_slave_abort - abort the ongoing transfer request on an SPI slave
2771 * controller
2772 * @spi: device used for the current transfer
2773 */
spi_slave_abort(struct spi_device * spi)2774 int spi_slave_abort(struct spi_device *spi)
2775 {
2776 struct spi_controller *ctlr = spi->controller;
2777
2778 if (spi_controller_is_slave(ctlr) && ctlr->slave_abort)
2779 return ctlr->slave_abort(ctlr);
2780
2781 return -ENOTSUPP;
2782 }
2783 EXPORT_SYMBOL_GPL(spi_slave_abort);
2784
spi_target_abort(struct spi_device * spi)2785 int spi_target_abort(struct spi_device *spi)
2786 {
2787 struct spi_controller *ctlr = spi->controller;
2788
2789 if (spi_controller_is_target(ctlr) && ctlr->target_abort)
2790 return ctlr->target_abort(ctlr);
2791
2792 return -ENOTSUPP;
2793 }
2794 EXPORT_SYMBOL_GPL(spi_target_abort);
2795
slave_show(struct device * dev,struct device_attribute * attr,char * buf)2796 static ssize_t slave_show(struct device *dev, struct device_attribute *attr,
2797 char *buf)
2798 {
2799 struct spi_controller *ctlr = container_of(dev, struct spi_controller,
2800 dev);
2801 struct device *child;
2802
2803 child = device_find_any_child(&ctlr->dev);
2804 return sysfs_emit(buf, "%s\n", child ? to_spi_device(child)->modalias : NULL);
2805 }
2806
slave_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)2807 static ssize_t slave_store(struct device *dev, struct device_attribute *attr,
2808 const char *buf, size_t count)
2809 {
2810 struct spi_controller *ctlr = container_of(dev, struct spi_controller,
2811 dev);
2812 struct spi_device *spi;
2813 struct device *child;
2814 char name[32];
2815 int rc;
2816
2817 rc = sscanf(buf, "%31s", name);
2818 if (rc != 1 || !name[0])
2819 return -EINVAL;
2820
2821 child = device_find_any_child(&ctlr->dev);
2822 if (child) {
2823 /* Remove registered slave */
2824 device_unregister(child);
2825 put_device(child);
2826 }
2827
2828 if (strcmp(name, "(null)")) {
2829 /* Register new slave */
2830 spi = spi_alloc_device(ctlr);
2831 if (!spi)
2832 return -ENOMEM;
2833
2834 strscpy(spi->modalias, name, sizeof(spi->modalias));
2835
2836 rc = spi_add_device(spi);
2837 if (rc) {
2838 spi_dev_put(spi);
2839 return rc;
2840 }
2841 }
2842
2843 return count;
2844 }
2845
2846 static DEVICE_ATTR_RW(slave);
2847
2848 static struct attribute *spi_slave_attrs[] = {
2849 &dev_attr_slave.attr,
2850 NULL,
2851 };
2852
2853 static const struct attribute_group spi_slave_group = {
2854 .attrs = spi_slave_attrs,
2855 };
2856
2857 static const struct attribute_group *spi_slave_groups[] = {
2858 &spi_controller_statistics_group,
2859 &spi_slave_group,
2860 NULL,
2861 };
2862
2863 static struct class spi_slave_class = {
2864 .name = "spi_slave",
2865 .dev_release = spi_controller_release,
2866 .dev_groups = spi_slave_groups,
2867 };
2868 #else
2869 extern struct class spi_slave_class; /* dummy */
2870 #endif
2871
2872 /**
2873 * __spi_alloc_controller - allocate an SPI master or slave controller
2874 * @dev: the controller, possibly using the platform_bus
2875 * @size: how much zeroed driver-private data to allocate; the pointer to this
2876 * memory is in the driver_data field of the returned device, accessible
2877 * with spi_controller_get_devdata(); the memory is cacheline aligned;
2878 * drivers granting DMA access to portions of their private data need to
2879 * round up @size using ALIGN(size, dma_get_cache_alignment()).
2880 * @slave: flag indicating whether to allocate an SPI master (false) or SPI
2881 * slave (true) controller
2882 * Context: can sleep
2883 *
2884 * This call is used only by SPI controller drivers, which are the
2885 * only ones directly touching chip registers. It's how they allocate
2886 * an spi_controller structure, prior to calling spi_register_controller().
2887 *
2888 * This must be called from context that can sleep.
2889 *
2890 * The caller is responsible for assigning the bus number and initializing the
2891 * controller's methods before calling spi_register_controller(); and (after
2892 * errors adding the device) calling spi_controller_put() to prevent a memory
2893 * leak.
2894 *
2895 * Return: the SPI controller structure on success, else NULL.
2896 */
__spi_alloc_controller(struct device * dev,unsigned int size,bool slave)2897 struct spi_controller *__spi_alloc_controller(struct device *dev,
2898 unsigned int size, bool slave)
2899 {
2900 struct spi_controller *ctlr;
2901 size_t ctlr_size = ALIGN(sizeof(*ctlr), dma_get_cache_alignment());
2902
2903 if (!dev)
2904 return NULL;
2905
2906 ctlr = kzalloc(size + ctlr_size, GFP_KERNEL);
2907 if (!ctlr)
2908 return NULL;
2909
2910 device_initialize(&ctlr->dev);
2911 INIT_LIST_HEAD(&ctlr->queue);
2912 spin_lock_init(&ctlr->queue_lock);
2913 spin_lock_init(&ctlr->bus_lock_spinlock);
2914 mutex_init(&ctlr->bus_lock_mutex);
2915 mutex_init(&ctlr->io_mutex);
2916 mutex_init(&ctlr->add_lock);
2917 ctlr->bus_num = -1;
2918 ctlr->num_chipselect = 1;
2919 ctlr->slave = slave;
2920 if (IS_ENABLED(CONFIG_SPI_SLAVE) && slave)
2921 ctlr->dev.class = &spi_slave_class;
2922 else
2923 ctlr->dev.class = &spi_master_class;
2924 ctlr->dev.parent = dev;
2925 pm_suspend_ignore_children(&ctlr->dev, true);
2926 spi_controller_set_devdata(ctlr, (void *)ctlr + ctlr_size);
2927
2928 return ctlr;
2929 }
2930 EXPORT_SYMBOL_GPL(__spi_alloc_controller);
2931
devm_spi_release_controller(struct device * dev,void * ctlr)2932 static void devm_spi_release_controller(struct device *dev, void *ctlr)
2933 {
2934 spi_controller_put(*(struct spi_controller **)ctlr);
2935 }
2936
2937 /**
2938 * __devm_spi_alloc_controller - resource-managed __spi_alloc_controller()
2939 * @dev: physical device of SPI controller
2940 * @size: how much zeroed driver-private data to allocate
2941 * @slave: whether to allocate an SPI master (false) or SPI slave (true)
2942 * Context: can sleep
2943 *
2944 * Allocate an SPI controller and automatically release a reference on it
2945 * when @dev is unbound from its driver. Drivers are thus relieved from
2946 * having to call spi_controller_put().
2947 *
2948 * The arguments to this function are identical to __spi_alloc_controller().
2949 *
2950 * Return: the SPI controller structure on success, else NULL.
2951 */
__devm_spi_alloc_controller(struct device * dev,unsigned int size,bool slave)2952 struct spi_controller *__devm_spi_alloc_controller(struct device *dev,
2953 unsigned int size,
2954 bool slave)
2955 {
2956 struct spi_controller **ptr, *ctlr;
2957
2958 ptr = devres_alloc(devm_spi_release_controller, sizeof(*ptr),
2959 GFP_KERNEL);
2960 if (!ptr)
2961 return NULL;
2962
2963 ctlr = __spi_alloc_controller(dev, size, slave);
2964 if (ctlr) {
2965 ctlr->devm_allocated = true;
2966 *ptr = ctlr;
2967 devres_add(dev, ptr);
2968 } else {
2969 devres_free(ptr);
2970 }
2971
2972 return ctlr;
2973 }
2974 EXPORT_SYMBOL_GPL(__devm_spi_alloc_controller);
2975
2976 /**
2977 * spi_get_gpio_descs() - grab chip select GPIOs for the master
2978 * @ctlr: The SPI master to grab GPIO descriptors for
2979 */
spi_get_gpio_descs(struct spi_controller * ctlr)2980 static int spi_get_gpio_descs(struct spi_controller *ctlr)
2981 {
2982 int nb, i;
2983 struct gpio_desc **cs;
2984 struct device *dev = &ctlr->dev;
2985 unsigned long native_cs_mask = 0;
2986 unsigned int num_cs_gpios = 0;
2987
2988 nb = gpiod_count(dev, "cs");
2989 if (nb < 0) {
2990 /* No GPIOs at all is fine, else return the error */
2991 if (nb == -ENOENT)
2992 return 0;
2993 return nb;
2994 }
2995
2996 ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
2997
2998 cs = devm_kcalloc(dev, ctlr->num_chipselect, sizeof(*cs),
2999 GFP_KERNEL);
3000 if (!cs)
3001 return -ENOMEM;
3002 ctlr->cs_gpiods = cs;
3003
3004 for (i = 0; i < nb; i++) {
3005 /*
3006 * Most chipselects are active low, the inverted
3007 * semantics are handled by special quirks in gpiolib,
3008 * so initializing them GPIOD_OUT_LOW here means
3009 * "unasserted", in most cases this will drive the physical
3010 * line high.
3011 */
3012 cs[i] = devm_gpiod_get_index_optional(dev, "cs", i,
3013 GPIOD_OUT_LOW);
3014 if (IS_ERR(cs[i]))
3015 return PTR_ERR(cs[i]);
3016
3017 if (cs[i]) {
3018 /*
3019 * If we find a CS GPIO, name it after the device and
3020 * chip select line.
3021 */
3022 char *gpioname;
3023
3024 gpioname = devm_kasprintf(dev, GFP_KERNEL, "%s CS%d",
3025 dev_name(dev), i);
3026 if (!gpioname)
3027 return -ENOMEM;
3028 gpiod_set_consumer_name(cs[i], gpioname);
3029 num_cs_gpios++;
3030 continue;
3031 }
3032
3033 if (ctlr->max_native_cs && i >= ctlr->max_native_cs) {
3034 dev_err(dev, "Invalid native chip select %d\n", i);
3035 return -EINVAL;
3036 }
3037 native_cs_mask |= BIT(i);
3038 }
3039
3040 ctlr->unused_native_cs = ffs(~native_cs_mask) - 1;
3041
3042 if ((ctlr->flags & SPI_CONTROLLER_GPIO_SS) && num_cs_gpios &&
3043 ctlr->max_native_cs && ctlr->unused_native_cs >= ctlr->max_native_cs) {
3044 dev_err(dev, "No unused native chip select available\n");
3045 return -EINVAL;
3046 }
3047
3048 return 0;
3049 }
3050
spi_controller_check_ops(struct spi_controller * ctlr)3051 static int spi_controller_check_ops(struct spi_controller *ctlr)
3052 {
3053 /*
3054 * The controller may implement only the high-level SPI-memory like
3055 * operations if it does not support regular SPI transfers, and this is
3056 * valid use case.
3057 * If ->mem_ops or ->mem_ops->exec_op is NULL, we request that at least
3058 * one of the ->transfer_xxx() method be implemented.
3059 */
3060 if (!ctlr->mem_ops || !ctlr->mem_ops->exec_op) {
3061 if (!ctlr->transfer && !ctlr->transfer_one &&
3062 !ctlr->transfer_one_message) {
3063 return -EINVAL;
3064 }
3065 }
3066
3067 return 0;
3068 }
3069
3070 /* Allocate dynamic bus number using Linux idr */
spi_controller_id_alloc(struct spi_controller * ctlr,int start,int end)3071 static int spi_controller_id_alloc(struct spi_controller *ctlr, int start, int end)
3072 {
3073 int id;
3074
3075 mutex_lock(&board_lock);
3076 id = idr_alloc(&spi_master_idr, ctlr, start, end, GFP_KERNEL);
3077 mutex_unlock(&board_lock);
3078 if (WARN(id < 0, "couldn't get idr"))
3079 return id == -ENOSPC ? -EBUSY : id;
3080 ctlr->bus_num = id;
3081 return 0;
3082 }
3083
3084 /**
3085 * spi_register_controller - register SPI master or slave controller
3086 * @ctlr: initialized master, originally from spi_alloc_master() or
3087 * spi_alloc_slave()
3088 * Context: can sleep
3089 *
3090 * SPI controllers connect to their drivers using some non-SPI bus,
3091 * such as the platform bus. The final stage of probe() in that code
3092 * includes calling spi_register_controller() to hook up to this SPI bus glue.
3093 *
3094 * SPI controllers use board specific (often SOC specific) bus numbers,
3095 * and board-specific addressing for SPI devices combines those numbers
3096 * with chip select numbers. Since SPI does not directly support dynamic
3097 * device identification, boards need configuration tables telling which
3098 * chip is at which address.
3099 *
3100 * This must be called from context that can sleep. It returns zero on
3101 * success, else a negative error code (dropping the controller's refcount).
3102 * After a successful return, the caller is responsible for calling
3103 * spi_unregister_controller().
3104 *
3105 * Return: zero on success, else a negative error code.
3106 */
spi_register_controller(struct spi_controller * ctlr)3107 int spi_register_controller(struct spi_controller *ctlr)
3108 {
3109 struct device *dev = ctlr->dev.parent;
3110 struct boardinfo *bi;
3111 int first_dynamic;
3112 int status;
3113
3114 if (!dev)
3115 return -ENODEV;
3116
3117 /*
3118 * Make sure all necessary hooks are implemented before registering
3119 * the SPI controller.
3120 */
3121 status = spi_controller_check_ops(ctlr);
3122 if (status)
3123 return status;
3124
3125 if (ctlr->bus_num < 0)
3126 ctlr->bus_num = of_alias_get_id(ctlr->dev.of_node, "spi");
3127 if (ctlr->bus_num >= 0) {
3128 /* Devices with a fixed bus num must check-in with the num */
3129 status = spi_controller_id_alloc(ctlr, ctlr->bus_num, ctlr->bus_num + 1);
3130 if (status)
3131 return status;
3132 }
3133 if (ctlr->bus_num < 0) {
3134 first_dynamic = of_alias_get_highest_id("spi");
3135 if (first_dynamic < 0)
3136 first_dynamic = 0;
3137 else
3138 first_dynamic++;
3139
3140 status = spi_controller_id_alloc(ctlr, first_dynamic, 0);
3141 if (status)
3142 return status;
3143 }
3144 ctlr->bus_lock_flag = 0;
3145 init_completion(&ctlr->xfer_completion);
3146 init_completion(&ctlr->cur_msg_completion);
3147 if (!ctlr->max_dma_len)
3148 ctlr->max_dma_len = INT_MAX;
3149
3150 /*
3151 * Register the device, then userspace will see it.
3152 * Registration fails if the bus ID is in use.
3153 */
3154 dev_set_name(&ctlr->dev, "spi%u", ctlr->bus_num);
3155
3156 if (!spi_controller_is_slave(ctlr) && ctlr->use_gpio_descriptors) {
3157 status = spi_get_gpio_descs(ctlr);
3158 if (status)
3159 goto free_bus_id;
3160 /*
3161 * A controller using GPIO descriptors always
3162 * supports SPI_CS_HIGH if need be.
3163 */
3164 ctlr->mode_bits |= SPI_CS_HIGH;
3165 }
3166
3167 /*
3168 * Even if it's just one always-selected device, there must
3169 * be at least one chipselect.
3170 */
3171 if (!ctlr->num_chipselect) {
3172 status = -EINVAL;
3173 goto free_bus_id;
3174 }
3175
3176 /* Setting last_cs to -1 means no chip selected */
3177 ctlr->last_cs = -1;
3178
3179 status = device_add(&ctlr->dev);
3180 if (status < 0)
3181 goto free_bus_id;
3182 dev_dbg(dev, "registered %s %s\n",
3183 spi_controller_is_slave(ctlr) ? "slave" : "master",
3184 dev_name(&ctlr->dev));
3185
3186 /*
3187 * If we're using a queued driver, start the queue. Note that we don't
3188 * need the queueing logic if the driver is only supporting high-level
3189 * memory operations.
3190 */
3191 if (ctlr->transfer) {
3192 dev_info(dev, "controller is unqueued, this is deprecated\n");
3193 } else if (ctlr->transfer_one || ctlr->transfer_one_message) {
3194 status = spi_controller_initialize_queue(ctlr);
3195 if (status) {
3196 device_del(&ctlr->dev);
3197 goto free_bus_id;
3198 }
3199 }
3200 /* Add statistics */
3201 ctlr->pcpu_statistics = spi_alloc_pcpu_stats(dev);
3202 if (!ctlr->pcpu_statistics) {
3203 dev_err(dev, "Error allocating per-cpu statistics\n");
3204 status = -ENOMEM;
3205 goto destroy_queue;
3206 }
3207
3208 mutex_lock(&board_lock);
3209 list_add_tail(&ctlr->list, &spi_controller_list);
3210 list_for_each_entry(bi, &board_list, list)
3211 spi_match_controller_to_boardinfo(ctlr, &bi->board_info);
3212 mutex_unlock(&board_lock);
3213
3214 /* Register devices from the device tree and ACPI */
3215 of_register_spi_devices(ctlr);
3216 acpi_register_spi_devices(ctlr);
3217 return status;
3218
3219 destroy_queue:
3220 spi_destroy_queue(ctlr);
3221 free_bus_id:
3222 mutex_lock(&board_lock);
3223 idr_remove(&spi_master_idr, ctlr->bus_num);
3224 mutex_unlock(&board_lock);
3225 return status;
3226 }
3227 EXPORT_SYMBOL_GPL(spi_register_controller);
3228
devm_spi_unregister(struct device * dev,void * res)3229 static void devm_spi_unregister(struct device *dev, void *res)
3230 {
3231 spi_unregister_controller(*(struct spi_controller **)res);
3232 }
3233
3234 /**
3235 * devm_spi_register_controller - register managed SPI master or slave
3236 * controller
3237 * @dev: device managing SPI controller
3238 * @ctlr: initialized controller, originally from spi_alloc_master() or
3239 * spi_alloc_slave()
3240 * Context: can sleep
3241 *
3242 * Register a SPI device as with spi_register_controller() which will
3243 * automatically be unregistered and freed.
3244 *
3245 * Return: zero on success, else a negative error code.
3246 */
devm_spi_register_controller(struct device * dev,struct spi_controller * ctlr)3247 int devm_spi_register_controller(struct device *dev,
3248 struct spi_controller *ctlr)
3249 {
3250 struct spi_controller **ptr;
3251 int ret;
3252
3253 ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
3254 if (!ptr)
3255 return -ENOMEM;
3256
3257 ret = spi_register_controller(ctlr);
3258 if (!ret) {
3259 *ptr = ctlr;
3260 devres_add(dev, ptr);
3261 } else {
3262 devres_free(ptr);
3263 }
3264
3265 return ret;
3266 }
3267 EXPORT_SYMBOL_GPL(devm_spi_register_controller);
3268
__unregister(struct device * dev,void * null)3269 static int __unregister(struct device *dev, void *null)
3270 {
3271 spi_unregister_device(to_spi_device(dev));
3272 return 0;
3273 }
3274
3275 /**
3276 * spi_unregister_controller - unregister SPI master or slave controller
3277 * @ctlr: the controller being unregistered
3278 * Context: can sleep
3279 *
3280 * This call is used only by SPI controller drivers, which are the
3281 * only ones directly touching chip registers.
3282 *
3283 * This must be called from context that can sleep.
3284 *
3285 * Note that this function also drops a reference to the controller.
3286 */
spi_unregister_controller(struct spi_controller * ctlr)3287 void spi_unregister_controller(struct spi_controller *ctlr)
3288 {
3289 struct spi_controller *found;
3290 int id = ctlr->bus_num;
3291
3292 /* Prevent addition of new devices, unregister existing ones */
3293 if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
3294 mutex_lock(&ctlr->add_lock);
3295
3296 device_for_each_child(&ctlr->dev, NULL, __unregister);
3297
3298 /* First make sure that this controller was ever added */
3299 mutex_lock(&board_lock);
3300 found = idr_find(&spi_master_idr, id);
3301 mutex_unlock(&board_lock);
3302 if (ctlr->queued) {
3303 if (spi_destroy_queue(ctlr))
3304 dev_err(&ctlr->dev, "queue remove failed\n");
3305 }
3306 mutex_lock(&board_lock);
3307 list_del(&ctlr->list);
3308 mutex_unlock(&board_lock);
3309
3310 device_del(&ctlr->dev);
3311
3312 /* Free bus id */
3313 mutex_lock(&board_lock);
3314 if (found == ctlr)
3315 idr_remove(&spi_master_idr, id);
3316 mutex_unlock(&board_lock);
3317
3318 if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
3319 mutex_unlock(&ctlr->add_lock);
3320
3321 /*
3322 * Release the last reference on the controller if its driver
3323 * has not yet been converted to devm_spi_alloc_master/slave().
3324 */
3325 if (!ctlr->devm_allocated)
3326 put_device(&ctlr->dev);
3327 }
3328 EXPORT_SYMBOL_GPL(spi_unregister_controller);
3329
__spi_check_suspended(const struct spi_controller * ctlr)3330 static inline int __spi_check_suspended(const struct spi_controller *ctlr)
3331 {
3332 return ctlr->flags & SPI_CONTROLLER_SUSPENDED ? -ESHUTDOWN : 0;
3333 }
3334
__spi_mark_suspended(struct spi_controller * ctlr)3335 static inline void __spi_mark_suspended(struct spi_controller *ctlr)
3336 {
3337 mutex_lock(&ctlr->bus_lock_mutex);
3338 ctlr->flags |= SPI_CONTROLLER_SUSPENDED;
3339 mutex_unlock(&ctlr->bus_lock_mutex);
3340 }
3341
__spi_mark_resumed(struct spi_controller * ctlr)3342 static inline void __spi_mark_resumed(struct spi_controller *ctlr)
3343 {
3344 mutex_lock(&ctlr->bus_lock_mutex);
3345 ctlr->flags &= ~SPI_CONTROLLER_SUSPENDED;
3346 mutex_unlock(&ctlr->bus_lock_mutex);
3347 }
3348
spi_controller_suspend(struct spi_controller * ctlr)3349 int spi_controller_suspend(struct spi_controller *ctlr)
3350 {
3351 int ret = 0;
3352
3353 /* Basically no-ops for non-queued controllers */
3354 if (ctlr->queued) {
3355 ret = spi_stop_queue(ctlr);
3356 if (ret)
3357 dev_err(&ctlr->dev, "queue stop failed\n");
3358 }
3359
3360 __spi_mark_suspended(ctlr);
3361 return ret;
3362 }
3363 EXPORT_SYMBOL_GPL(spi_controller_suspend);
3364
spi_controller_resume(struct spi_controller * ctlr)3365 int spi_controller_resume(struct spi_controller *ctlr)
3366 {
3367 int ret = 0;
3368
3369 __spi_mark_resumed(ctlr);
3370
3371 if (ctlr->queued) {
3372 ret = spi_start_queue(ctlr);
3373 if (ret)
3374 dev_err(&ctlr->dev, "queue restart failed\n");
3375 }
3376 return ret;
3377 }
3378 EXPORT_SYMBOL_GPL(spi_controller_resume);
3379
3380 /*-------------------------------------------------------------------------*/
3381
3382 /* Core methods for spi_message alterations */
3383
__spi_replace_transfers_release(struct spi_controller * ctlr,struct spi_message * msg,void * res)3384 static void __spi_replace_transfers_release(struct spi_controller *ctlr,
3385 struct spi_message *msg,
3386 void *res)
3387 {
3388 struct spi_replaced_transfers *rxfer = res;
3389 size_t i;
3390
3391 /* Call extra callback if requested */
3392 if (rxfer->release)
3393 rxfer->release(ctlr, msg, res);
3394
3395 /* Insert replaced transfers back into the message */
3396 list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
3397
3398 /* Remove the formerly inserted entries */
3399 for (i = 0; i < rxfer->inserted; i++)
3400 list_del(&rxfer->inserted_transfers[i].transfer_list);
3401 }
3402
3403 /**
3404 * spi_replace_transfers - replace transfers with several transfers
3405 * and register change with spi_message.resources
3406 * @msg: the spi_message we work upon
3407 * @xfer_first: the first spi_transfer we want to replace
3408 * @remove: number of transfers to remove
3409 * @insert: the number of transfers we want to insert instead
3410 * @release: extra release code necessary in some circumstances
3411 * @extradatasize: extra data to allocate (with alignment guarantees
3412 * of struct @spi_transfer)
3413 * @gfp: gfp flags
3414 *
3415 * Returns: pointer to @spi_replaced_transfers,
3416 * PTR_ERR(...) in case of errors.
3417 */
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)3418 static struct spi_replaced_transfers *spi_replace_transfers(
3419 struct spi_message *msg,
3420 struct spi_transfer *xfer_first,
3421 size_t remove,
3422 size_t insert,
3423 spi_replaced_release_t release,
3424 size_t extradatasize,
3425 gfp_t gfp)
3426 {
3427 struct spi_replaced_transfers *rxfer;
3428 struct spi_transfer *xfer;
3429 size_t i;
3430
3431 /* Allocate the structure using spi_res */
3432 rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
3433 struct_size(rxfer, inserted_transfers, insert)
3434 + extradatasize,
3435 gfp);
3436 if (!rxfer)
3437 return ERR_PTR(-ENOMEM);
3438
3439 /* The release code to invoke before running the generic release */
3440 rxfer->release = release;
3441
3442 /* Assign extradata */
3443 if (extradatasize)
3444 rxfer->extradata =
3445 &rxfer->inserted_transfers[insert];
3446
3447 /* Init the replaced_transfers list */
3448 INIT_LIST_HEAD(&rxfer->replaced_transfers);
3449
3450 /*
3451 * Assign the list_entry after which we should reinsert
3452 * the @replaced_transfers - it may be spi_message.messages!
3453 */
3454 rxfer->replaced_after = xfer_first->transfer_list.prev;
3455
3456 /* Remove the requested number of transfers */
3457 for (i = 0; i < remove; i++) {
3458 /*
3459 * If the entry after replaced_after it is msg->transfers
3460 * then we have been requested to remove more transfers
3461 * than are in the list.
3462 */
3463 if (rxfer->replaced_after->next == &msg->transfers) {
3464 dev_err(&msg->spi->dev,
3465 "requested to remove more spi_transfers than are available\n");
3466 /* Insert replaced transfers back into the message */
3467 list_splice(&rxfer->replaced_transfers,
3468 rxfer->replaced_after);
3469
3470 /* Free the spi_replace_transfer structure... */
3471 spi_res_free(rxfer);
3472
3473 /* ...and return with an error */
3474 return ERR_PTR(-EINVAL);
3475 }
3476
3477 /*
3478 * Remove the entry after replaced_after from list of
3479 * transfers and add it to list of replaced_transfers.
3480 */
3481 list_move_tail(rxfer->replaced_after->next,
3482 &rxfer->replaced_transfers);
3483 }
3484
3485 /*
3486 * Create copy of the given xfer with identical settings
3487 * based on the first transfer to get removed.
3488 */
3489 for (i = 0; i < insert; i++) {
3490 /* We need to run in reverse order */
3491 xfer = &rxfer->inserted_transfers[insert - 1 - i];
3492
3493 /* Copy all spi_transfer data */
3494 memcpy(xfer, xfer_first, sizeof(*xfer));
3495
3496 /* Add to list */
3497 list_add(&xfer->transfer_list, rxfer->replaced_after);
3498
3499 /* Clear cs_change and delay for all but the last */
3500 if (i) {
3501 xfer->cs_change = false;
3502 xfer->delay.value = 0;
3503 }
3504 }
3505
3506 /* Set up inserted... */
3507 rxfer->inserted = insert;
3508
3509 /* ...and register it with spi_res/spi_message */
3510 spi_res_add(msg, rxfer);
3511
3512 return rxfer;
3513 }
3514
__spi_split_transfer_maxsize(struct spi_controller * ctlr,struct spi_message * msg,struct spi_transfer ** xferp,size_t maxsize,gfp_t gfp)3515 static int __spi_split_transfer_maxsize(struct spi_controller *ctlr,
3516 struct spi_message *msg,
3517 struct spi_transfer **xferp,
3518 size_t maxsize,
3519 gfp_t gfp)
3520 {
3521 struct spi_transfer *xfer = *xferp, *xfers;
3522 struct spi_replaced_transfers *srt;
3523 size_t offset;
3524 size_t count, i;
3525
3526 /* Calculate how many we have to replace */
3527 count = DIV_ROUND_UP(xfer->len, maxsize);
3528
3529 /* Create replacement */
3530 srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, gfp);
3531 if (IS_ERR(srt))
3532 return PTR_ERR(srt);
3533 xfers = srt->inserted_transfers;
3534
3535 /*
3536 * Now handle each of those newly inserted spi_transfers.
3537 * Note that the replacements spi_transfers all are preset
3538 * to the same values as *xferp, so tx_buf, rx_buf and len
3539 * are all identical (as well as most others)
3540 * so we just have to fix up len and the pointers.
3541 *
3542 * This also includes support for the depreciated
3543 * spi_message.is_dma_mapped interface.
3544 */
3545
3546 /*
3547 * The first transfer just needs the length modified, so we
3548 * run it outside the loop.
3549 */
3550 xfers[0].len = min_t(size_t, maxsize, xfer[0].len);
3551
3552 /* All the others need rx_buf/tx_buf also set */
3553 for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) {
3554 /* Update rx_buf, tx_buf and DMA */
3555 if (xfers[i].rx_buf)
3556 xfers[i].rx_buf += offset;
3557 if (xfers[i].rx_dma)
3558 xfers[i].rx_dma += offset;
3559 if (xfers[i].tx_buf)
3560 xfers[i].tx_buf += offset;
3561 if (xfers[i].tx_dma)
3562 xfers[i].tx_dma += offset;
3563
3564 /* Update length */
3565 xfers[i].len = min(maxsize, xfers[i].len - offset);
3566 }
3567
3568 /*
3569 * We set up xferp to the last entry we have inserted,
3570 * so that we skip those already split transfers.
3571 */
3572 *xferp = &xfers[count - 1];
3573
3574 /* Increment statistics counters */
3575 SPI_STATISTICS_INCREMENT_FIELD(ctlr->pcpu_statistics,
3576 transfers_split_maxsize);
3577 SPI_STATISTICS_INCREMENT_FIELD(msg->spi->pcpu_statistics,
3578 transfers_split_maxsize);
3579
3580 return 0;
3581 }
3582
3583 /**
3584 * spi_split_transfers_maxsize - split spi transfers into multiple transfers
3585 * when an individual transfer exceeds a
3586 * certain size
3587 * @ctlr: the @spi_controller for this transfer
3588 * @msg: the @spi_message to transform
3589 * @maxsize: the maximum when to apply this
3590 * @gfp: GFP allocation flags
3591 *
3592 * Return: status of transformation
3593 */
spi_split_transfers_maxsize(struct spi_controller * ctlr,struct spi_message * msg,size_t maxsize,gfp_t gfp)3594 int spi_split_transfers_maxsize(struct spi_controller *ctlr,
3595 struct spi_message *msg,
3596 size_t maxsize,
3597 gfp_t gfp)
3598 {
3599 struct spi_transfer *xfer;
3600 int ret;
3601
3602 /*
3603 * Iterate over the transfer_list,
3604 * but note that xfer is advanced to the last transfer inserted
3605 * to avoid checking sizes again unnecessarily (also xfer does
3606 * potentially belong to a different list by the time the
3607 * replacement has happened).
3608 */
3609 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
3610 if (xfer->len > maxsize) {
3611 ret = __spi_split_transfer_maxsize(ctlr, msg, &xfer,
3612 maxsize, gfp);
3613 if (ret)
3614 return ret;
3615 }
3616 }
3617
3618 return 0;
3619 }
3620 EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize);
3621
3622
3623 /**
3624 * spi_split_transfers_maxwords - split SPI transfers into multiple transfers
3625 * when an individual transfer exceeds a
3626 * certain number of SPI words
3627 * @ctlr: the @spi_controller for this transfer
3628 * @msg: the @spi_message to transform
3629 * @maxwords: the number of words to limit each transfer to
3630 * @gfp: GFP allocation flags
3631 *
3632 * Return: status of transformation
3633 */
spi_split_transfers_maxwords(struct spi_controller * ctlr,struct spi_message * msg,size_t maxwords,gfp_t gfp)3634 int spi_split_transfers_maxwords(struct spi_controller *ctlr,
3635 struct spi_message *msg,
3636 size_t maxwords,
3637 gfp_t gfp)
3638 {
3639 struct spi_transfer *xfer;
3640
3641 /*
3642 * Iterate over the transfer_list,
3643 * but note that xfer is advanced to the last transfer inserted
3644 * to avoid checking sizes again unnecessarily (also xfer does
3645 * potentially belong to a different list by the time the
3646 * replacement has happened).
3647 */
3648 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
3649 size_t maxsize;
3650 int ret;
3651
3652 maxsize = maxwords * roundup_pow_of_two(BITS_TO_BYTES(xfer->bits_per_word));
3653 if (xfer->len > maxsize) {
3654 ret = __spi_split_transfer_maxsize(ctlr, msg, &xfer,
3655 maxsize, gfp);
3656 if (ret)
3657 return ret;
3658 }
3659 }
3660
3661 return 0;
3662 }
3663 EXPORT_SYMBOL_GPL(spi_split_transfers_maxwords);
3664
3665 /*-------------------------------------------------------------------------*/
3666
3667 /*
3668 * Core methods for SPI controller protocol drivers. Some of the
3669 * other core methods are currently defined as inline functions.
3670 */
3671
__spi_validate_bits_per_word(struct spi_controller * ctlr,u8 bits_per_word)3672 static int __spi_validate_bits_per_word(struct spi_controller *ctlr,
3673 u8 bits_per_word)
3674 {
3675 if (ctlr->bits_per_word_mask) {
3676 /* Only 32 bits fit in the mask */
3677 if (bits_per_word > 32)
3678 return -EINVAL;
3679 if (!(ctlr->bits_per_word_mask & SPI_BPW_MASK(bits_per_word)))
3680 return -EINVAL;
3681 }
3682
3683 return 0;
3684 }
3685
3686 /**
3687 * spi_set_cs_timing - configure CS setup, hold, and inactive delays
3688 * @spi: the device that requires specific CS timing configuration
3689 *
3690 * Return: zero on success, else a negative error code.
3691 */
spi_set_cs_timing(struct spi_device * spi)3692 static int spi_set_cs_timing(struct spi_device *spi)
3693 {
3694 struct device *parent = spi->controller->dev.parent;
3695 int status = 0;
3696
3697 if (spi->controller->set_cs_timing && !spi_get_csgpiod(spi, 0)) {
3698 if (spi->controller->auto_runtime_pm) {
3699 status = pm_runtime_get_sync(parent);
3700 if (status < 0) {
3701 pm_runtime_put_noidle(parent);
3702 dev_err(&spi->controller->dev, "Failed to power device: %d\n",
3703 status);
3704 return status;
3705 }
3706
3707 status = spi->controller->set_cs_timing(spi);
3708 pm_runtime_mark_last_busy(parent);
3709 pm_runtime_put_autosuspend(parent);
3710 } else {
3711 status = spi->controller->set_cs_timing(spi);
3712 }
3713 }
3714 return status;
3715 }
3716
3717 /**
3718 * spi_setup - setup SPI mode and clock rate
3719 * @spi: the device whose settings are being modified
3720 * Context: can sleep, and no requests are queued to the device
3721 *
3722 * SPI protocol drivers may need to update the transfer mode if the
3723 * device doesn't work with its default. They may likewise need
3724 * to update clock rates or word sizes from initial values. This function
3725 * changes those settings, and must be called from a context that can sleep.
3726 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
3727 * effect the next time the device is selected and data is transferred to
3728 * or from it. When this function returns, the SPI device is deselected.
3729 *
3730 * Note that this call will fail if the protocol driver specifies an option
3731 * that the underlying controller or its driver does not support. For
3732 * example, not all hardware supports wire transfers using nine bit words,
3733 * LSB-first wire encoding, or active-high chipselects.
3734 *
3735 * Return: zero on success, else a negative error code.
3736 */
spi_setup(struct spi_device * spi)3737 int spi_setup(struct spi_device *spi)
3738 {
3739 unsigned bad_bits, ugly_bits;
3740 int status = 0;
3741
3742 /*
3743 * Check mode to prevent that any two of DUAL, QUAD and NO_MOSI/MISO
3744 * are set at the same time.
3745 */
3746 if ((hweight_long(spi->mode &
3747 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_NO_TX)) > 1) ||
3748 (hweight_long(spi->mode &
3749 (SPI_RX_DUAL | SPI_RX_QUAD | SPI_NO_RX)) > 1)) {
3750 dev_err(&spi->dev,
3751 "setup: can not select any two of dual, quad and no-rx/tx at the same time\n");
3752 return -EINVAL;
3753 }
3754 /* If it is SPI_3WIRE mode, DUAL and QUAD should be forbidden */
3755 if ((spi->mode & SPI_3WIRE) && (spi->mode &
3756 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
3757 SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL)))
3758 return -EINVAL;
3759 /*
3760 * Help drivers fail *cleanly* when they need options
3761 * that aren't supported with their current controller.
3762 * SPI_CS_WORD has a fallback software implementation,
3763 * so it is ignored here.
3764 */
3765 bad_bits = spi->mode & ~(spi->controller->mode_bits | SPI_CS_WORD |
3766 SPI_NO_TX | SPI_NO_RX);
3767 ugly_bits = bad_bits &
3768 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
3769 SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL);
3770 if (ugly_bits) {
3771 dev_warn(&spi->dev,
3772 "setup: ignoring unsupported mode bits %x\n",
3773 ugly_bits);
3774 spi->mode &= ~ugly_bits;
3775 bad_bits &= ~ugly_bits;
3776 }
3777 if (bad_bits) {
3778 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
3779 bad_bits);
3780 return -EINVAL;
3781 }
3782
3783 if (!spi->bits_per_word) {
3784 spi->bits_per_word = 8;
3785 } else {
3786 /*
3787 * Some controllers may not support the default 8 bits-per-word
3788 * so only perform the check when this is explicitly provided.
3789 */
3790 status = __spi_validate_bits_per_word(spi->controller,
3791 spi->bits_per_word);
3792 if (status)
3793 return status;
3794 }
3795
3796 if (spi->controller->max_speed_hz &&
3797 (!spi->max_speed_hz ||
3798 spi->max_speed_hz > spi->controller->max_speed_hz))
3799 spi->max_speed_hz = spi->controller->max_speed_hz;
3800
3801 mutex_lock(&spi->controller->io_mutex);
3802
3803 if (spi->controller->setup) {
3804 status = spi->controller->setup(spi);
3805 if (status) {
3806 mutex_unlock(&spi->controller->io_mutex);
3807 dev_err(&spi->controller->dev, "Failed to setup device: %d\n",
3808 status);
3809 return status;
3810 }
3811 }
3812
3813 status = spi_set_cs_timing(spi);
3814 if (status) {
3815 mutex_unlock(&spi->controller->io_mutex);
3816 return status;
3817 }
3818
3819 if (spi->controller->auto_runtime_pm && spi->controller->set_cs) {
3820 status = pm_runtime_resume_and_get(spi->controller->dev.parent);
3821 if (status < 0) {
3822 mutex_unlock(&spi->controller->io_mutex);
3823 dev_err(&spi->controller->dev, "Failed to power device: %d\n",
3824 status);
3825 return status;
3826 }
3827
3828 /*
3829 * We do not want to return positive value from pm_runtime_get,
3830 * there are many instances of devices calling spi_setup() and
3831 * checking for a non-zero return value instead of a negative
3832 * return value.
3833 */
3834 status = 0;
3835
3836 spi_set_cs(spi, false, true);
3837 pm_runtime_mark_last_busy(spi->controller->dev.parent);
3838 pm_runtime_put_autosuspend(spi->controller->dev.parent);
3839 } else {
3840 spi_set_cs(spi, false, true);
3841 }
3842
3843 mutex_unlock(&spi->controller->io_mutex);
3844
3845 if (spi->rt && !spi->controller->rt) {
3846 spi->controller->rt = true;
3847 spi_set_thread_rt(spi->controller);
3848 }
3849
3850 trace_spi_setup(spi, status);
3851
3852 dev_dbg(&spi->dev, "setup mode %lu, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
3853 spi->mode & SPI_MODE_X_MASK,
3854 (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
3855 (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
3856 (spi->mode & SPI_3WIRE) ? "3wire, " : "",
3857 (spi->mode & SPI_LOOP) ? "loopback, " : "",
3858 spi->bits_per_word, spi->max_speed_hz,
3859 status);
3860
3861 return status;
3862 }
3863 EXPORT_SYMBOL_GPL(spi_setup);
3864
_spi_xfer_word_delay_update(struct spi_transfer * xfer,struct spi_device * spi)3865 static int _spi_xfer_word_delay_update(struct spi_transfer *xfer,
3866 struct spi_device *spi)
3867 {
3868 int delay1, delay2;
3869
3870 delay1 = spi_delay_to_ns(&xfer->word_delay, xfer);
3871 if (delay1 < 0)
3872 return delay1;
3873
3874 delay2 = spi_delay_to_ns(&spi->word_delay, xfer);
3875 if (delay2 < 0)
3876 return delay2;
3877
3878 if (delay1 < delay2)
3879 memcpy(&xfer->word_delay, &spi->word_delay,
3880 sizeof(xfer->word_delay));
3881
3882 return 0;
3883 }
3884
__spi_validate(struct spi_device * spi,struct spi_message * message)3885 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
3886 {
3887 struct spi_controller *ctlr = spi->controller;
3888 struct spi_transfer *xfer;
3889 int w_size;
3890
3891 if (list_empty(&message->transfers))
3892 return -EINVAL;
3893
3894 /*
3895 * If an SPI controller does not support toggling the CS line on each
3896 * transfer (indicated by the SPI_CS_WORD flag) or we are using a GPIO
3897 * for the CS line, we can emulate the CS-per-word hardware function by
3898 * splitting transfers into one-word transfers and ensuring that
3899 * cs_change is set for each transfer.
3900 */
3901 if ((spi->mode & SPI_CS_WORD) && (!(ctlr->mode_bits & SPI_CS_WORD) ||
3902 spi_get_csgpiod(spi, 0))) {
3903 size_t maxsize = BITS_TO_BYTES(spi->bits_per_word);
3904 int ret;
3905
3906 /* spi_split_transfers_maxsize() requires message->spi */
3907 message->spi = spi;
3908
3909 ret = spi_split_transfers_maxsize(ctlr, message, maxsize,
3910 GFP_KERNEL);
3911 if (ret)
3912 return ret;
3913
3914 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3915 /* Don't change cs_change on the last entry in the list */
3916 if (list_is_last(&xfer->transfer_list, &message->transfers))
3917 break;
3918 xfer->cs_change = 1;
3919 }
3920 }
3921
3922 /*
3923 * Half-duplex links include original MicroWire, and ones with
3924 * only one data pin like SPI_3WIRE (switches direction) or where
3925 * either MOSI or MISO is missing. They can also be caused by
3926 * software limitations.
3927 */
3928 if ((ctlr->flags & SPI_CONTROLLER_HALF_DUPLEX) ||
3929 (spi->mode & SPI_3WIRE)) {
3930 unsigned flags = ctlr->flags;
3931
3932 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3933 if (xfer->rx_buf && xfer->tx_buf)
3934 return -EINVAL;
3935 if ((flags & SPI_CONTROLLER_NO_TX) && xfer->tx_buf)
3936 return -EINVAL;
3937 if ((flags & SPI_CONTROLLER_NO_RX) && xfer->rx_buf)
3938 return -EINVAL;
3939 }
3940 }
3941
3942 /*
3943 * Set transfer bits_per_word and max speed as spi device default if
3944 * it is not set for this transfer.
3945 * Set transfer tx_nbits and rx_nbits as single transfer default
3946 * (SPI_NBITS_SINGLE) if it is not set for this transfer.
3947 * Ensure transfer word_delay is at least as long as that required by
3948 * device itself.
3949 */
3950 message->frame_length = 0;
3951 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3952 xfer->effective_speed_hz = 0;
3953 message->frame_length += xfer->len;
3954 if (!xfer->bits_per_word)
3955 xfer->bits_per_word = spi->bits_per_word;
3956
3957 if (!xfer->speed_hz)
3958 xfer->speed_hz = spi->max_speed_hz;
3959
3960 if (ctlr->max_speed_hz && xfer->speed_hz > ctlr->max_speed_hz)
3961 xfer->speed_hz = ctlr->max_speed_hz;
3962
3963 if (__spi_validate_bits_per_word(ctlr, xfer->bits_per_word))
3964 return -EINVAL;
3965
3966 /*
3967 * SPI transfer length should be multiple of SPI word size
3968 * where SPI word size should be power-of-two multiple.
3969 */
3970 if (xfer->bits_per_word <= 8)
3971 w_size = 1;
3972 else if (xfer->bits_per_word <= 16)
3973 w_size = 2;
3974 else
3975 w_size = 4;
3976
3977 /* No partial transfers accepted */
3978 if (xfer->len % w_size)
3979 return -EINVAL;
3980
3981 if (xfer->speed_hz && ctlr->min_speed_hz &&
3982 xfer->speed_hz < ctlr->min_speed_hz)
3983 return -EINVAL;
3984
3985 if (xfer->tx_buf && !xfer->tx_nbits)
3986 xfer->tx_nbits = SPI_NBITS_SINGLE;
3987 if (xfer->rx_buf && !xfer->rx_nbits)
3988 xfer->rx_nbits = SPI_NBITS_SINGLE;
3989 /*
3990 * Check transfer tx/rx_nbits:
3991 * 1. check the value matches one of single, dual and quad
3992 * 2. check tx/rx_nbits match the mode in spi_device
3993 */
3994 if (xfer->tx_buf) {
3995 if (spi->mode & SPI_NO_TX)
3996 return -EINVAL;
3997 if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
3998 xfer->tx_nbits != SPI_NBITS_DUAL &&
3999 xfer->tx_nbits != SPI_NBITS_QUAD)
4000 return -EINVAL;
4001 if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
4002 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
4003 return -EINVAL;
4004 if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
4005 !(spi->mode & SPI_TX_QUAD))
4006 return -EINVAL;
4007 }
4008 /* Check transfer rx_nbits */
4009 if (xfer->rx_buf) {
4010 if (spi->mode & SPI_NO_RX)
4011 return -EINVAL;
4012 if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
4013 xfer->rx_nbits != SPI_NBITS_DUAL &&
4014 xfer->rx_nbits != SPI_NBITS_QUAD)
4015 return -EINVAL;
4016 if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
4017 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
4018 return -EINVAL;
4019 if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
4020 !(spi->mode & SPI_RX_QUAD))
4021 return -EINVAL;
4022 }
4023
4024 if (_spi_xfer_word_delay_update(xfer, spi))
4025 return -EINVAL;
4026 }
4027
4028 message->status = -EINPROGRESS;
4029
4030 return 0;
4031 }
4032
__spi_async(struct spi_device * spi,struct spi_message * message)4033 static int __spi_async(struct spi_device *spi, struct spi_message *message)
4034 {
4035 struct spi_controller *ctlr = spi->controller;
4036 struct spi_transfer *xfer;
4037
4038 /*
4039 * Some controllers do not support doing regular SPI transfers. Return
4040 * ENOTSUPP when this is the case.
4041 */
4042 if (!ctlr->transfer)
4043 return -ENOTSUPP;
4044
4045 message->spi = spi;
4046
4047 SPI_STATISTICS_INCREMENT_FIELD(ctlr->pcpu_statistics, spi_async);
4048 SPI_STATISTICS_INCREMENT_FIELD(spi->pcpu_statistics, spi_async);
4049
4050 trace_spi_message_submit(message);
4051
4052 if (!ctlr->ptp_sts_supported) {
4053 list_for_each_entry(xfer, &message->transfers, transfer_list) {
4054 xfer->ptp_sts_word_pre = 0;
4055 ptp_read_system_prets(xfer->ptp_sts);
4056 }
4057 }
4058
4059 return ctlr->transfer(spi, message);
4060 }
4061
4062 /**
4063 * spi_async - asynchronous SPI transfer
4064 * @spi: device with which data will be exchanged
4065 * @message: describes the data transfers, including completion callback
4066 * Context: any (IRQs may be blocked, etc)
4067 *
4068 * This call may be used in_irq and other contexts which can't sleep,
4069 * as well as from task contexts which can sleep.
4070 *
4071 * The completion callback is invoked in a context which can't sleep.
4072 * Before that invocation, the value of message->status is undefined.
4073 * When the callback is issued, message->status holds either zero (to
4074 * indicate complete success) or a negative error code. After that
4075 * callback returns, the driver which issued the transfer request may
4076 * deallocate the associated memory; it's no longer in use by any SPI
4077 * core or controller driver code.
4078 *
4079 * Note that although all messages to a spi_device are handled in
4080 * FIFO order, messages may go to different devices in other orders.
4081 * Some device might be higher priority, or have various "hard" access
4082 * time requirements, for example.
4083 *
4084 * On detection of any fault during the transfer, processing of
4085 * the entire message is aborted, and the device is deselected.
4086 * Until returning from the associated message completion callback,
4087 * no other spi_message queued to that device will be processed.
4088 * (This rule applies equally to all the synchronous transfer calls,
4089 * which are wrappers around this core asynchronous primitive.)
4090 *
4091 * Return: zero on success, else a negative error code.
4092 */
spi_async(struct spi_device * spi,struct spi_message * message)4093 int spi_async(struct spi_device *spi, struct spi_message *message)
4094 {
4095 struct spi_controller *ctlr = spi->controller;
4096 int ret;
4097 unsigned long flags;
4098
4099 ret = __spi_validate(spi, message);
4100 if (ret != 0)
4101 return ret;
4102
4103 spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
4104
4105 if (ctlr->bus_lock_flag)
4106 ret = -EBUSY;
4107 else
4108 ret = __spi_async(spi, message);
4109
4110 spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
4111
4112 return ret;
4113 }
4114 EXPORT_SYMBOL_GPL(spi_async);
4115
4116 /**
4117 * spi_async_locked - version of spi_async with exclusive bus usage
4118 * @spi: device with which data will be exchanged
4119 * @message: describes the data transfers, including completion callback
4120 * Context: any (IRQs may be blocked, etc)
4121 *
4122 * This call may be used in_irq and other contexts which can't sleep,
4123 * as well as from task contexts which can sleep.
4124 *
4125 * The completion callback is invoked in a context which can't sleep.
4126 * Before that invocation, the value of message->status is undefined.
4127 * When the callback is issued, message->status holds either zero (to
4128 * indicate complete success) or a negative error code. After that
4129 * callback returns, the driver which issued the transfer request may
4130 * deallocate the associated memory; it's no longer in use by any SPI
4131 * core or controller driver code.
4132 *
4133 * Note that although all messages to a spi_device are handled in
4134 * FIFO order, messages may go to different devices in other orders.
4135 * Some device might be higher priority, or have various "hard" access
4136 * time requirements, for example.
4137 *
4138 * On detection of any fault during the transfer, processing of
4139 * the entire message is aborted, and the device is deselected.
4140 * Until returning from the associated message completion callback,
4141 * no other spi_message queued to that device will be processed.
4142 * (This rule applies equally to all the synchronous transfer calls,
4143 * which are wrappers around this core asynchronous primitive.)
4144 *
4145 * Return: zero on success, else a negative error code.
4146 */
spi_async_locked(struct spi_device * spi,struct spi_message * message)4147 static int spi_async_locked(struct spi_device *spi, struct spi_message *message)
4148 {
4149 struct spi_controller *ctlr = spi->controller;
4150 int ret;
4151 unsigned long flags;
4152
4153 ret = __spi_validate(spi, message);
4154 if (ret != 0)
4155 return ret;
4156
4157 spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
4158
4159 ret = __spi_async(spi, message);
4160
4161 spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
4162
4163 return ret;
4164
4165 }
4166
__spi_transfer_message_noqueue(struct spi_controller * ctlr,struct spi_message * msg)4167 static void __spi_transfer_message_noqueue(struct spi_controller *ctlr, struct spi_message *msg)
4168 {
4169 bool was_busy;
4170 int ret;
4171
4172 mutex_lock(&ctlr->io_mutex);
4173
4174 was_busy = ctlr->busy;
4175
4176 ctlr->cur_msg = msg;
4177 ret = __spi_pump_transfer_message(ctlr, msg, was_busy);
4178 if (ret)
4179 dev_err(&ctlr->dev, "noqueue transfer failed\n");
4180 ctlr->cur_msg = NULL;
4181 ctlr->fallback = false;
4182
4183 if (!was_busy) {
4184 kfree(ctlr->dummy_rx);
4185 ctlr->dummy_rx = NULL;
4186 kfree(ctlr->dummy_tx);
4187 ctlr->dummy_tx = NULL;
4188 if (ctlr->unprepare_transfer_hardware &&
4189 ctlr->unprepare_transfer_hardware(ctlr))
4190 dev_err(&ctlr->dev,
4191 "failed to unprepare transfer hardware\n");
4192 spi_idle_runtime_pm(ctlr);
4193 }
4194
4195 mutex_unlock(&ctlr->io_mutex);
4196 }
4197
4198 /*-------------------------------------------------------------------------*/
4199
4200 /*
4201 * Utility methods for SPI protocol drivers, layered on
4202 * top of the core. Some other utility methods are defined as
4203 * inline functions.
4204 */
4205
spi_complete(void * arg)4206 static void spi_complete(void *arg)
4207 {
4208 complete(arg);
4209 }
4210
__spi_sync(struct spi_device * spi,struct spi_message * message)4211 static int __spi_sync(struct spi_device *spi, struct spi_message *message)
4212 {
4213 DECLARE_COMPLETION_ONSTACK(done);
4214 int status;
4215 struct spi_controller *ctlr = spi->controller;
4216
4217 if (__spi_check_suspended(ctlr)) {
4218 dev_warn_once(&spi->dev, "Attempted to sync while suspend\n");
4219 return -ESHUTDOWN;
4220 }
4221
4222 status = __spi_validate(spi, message);
4223 if (status != 0)
4224 return status;
4225
4226 message->spi = spi;
4227
4228 SPI_STATISTICS_INCREMENT_FIELD(ctlr->pcpu_statistics, spi_sync);
4229 SPI_STATISTICS_INCREMENT_FIELD(spi->pcpu_statistics, spi_sync);
4230
4231 /*
4232 * Checking queue_empty here only guarantees async/sync message
4233 * ordering when coming from the same context. It does not need to
4234 * guard against reentrancy from a different context. The io_mutex
4235 * will catch those cases.
4236 */
4237 if (READ_ONCE(ctlr->queue_empty) && !ctlr->must_async) {
4238 message->actual_length = 0;
4239 message->status = -EINPROGRESS;
4240
4241 trace_spi_message_submit(message);
4242
4243 SPI_STATISTICS_INCREMENT_FIELD(ctlr->pcpu_statistics, spi_sync_immediate);
4244 SPI_STATISTICS_INCREMENT_FIELD(spi->pcpu_statistics, spi_sync_immediate);
4245
4246 __spi_transfer_message_noqueue(ctlr, message);
4247
4248 return message->status;
4249 }
4250
4251 /*
4252 * There are messages in the async queue that could have originated
4253 * from the same context, so we need to preserve ordering.
4254 * Therefor we send the message to the async queue and wait until they
4255 * are completed.
4256 */
4257 message->complete = spi_complete;
4258 message->context = &done;
4259 status = spi_async_locked(spi, message);
4260 if (status == 0) {
4261 wait_for_completion(&done);
4262 status = message->status;
4263 }
4264 message->context = NULL;
4265
4266 return status;
4267 }
4268
4269 /**
4270 * spi_sync - blocking/synchronous SPI data transfers
4271 * @spi: device with which data will be exchanged
4272 * @message: describes the data transfers
4273 * Context: can sleep
4274 *
4275 * This call may only be used from a context that may sleep. The sleep
4276 * is non-interruptible, and has no timeout. Low-overhead controller
4277 * drivers may DMA directly into and out of the message buffers.
4278 *
4279 * Note that the SPI device's chip select is active during the message,
4280 * and then is normally disabled between messages. Drivers for some
4281 * frequently-used devices may want to minimize costs of selecting a chip,
4282 * by leaving it selected in anticipation that the next message will go
4283 * to the same chip. (That may increase power usage.)
4284 *
4285 * Also, the caller is guaranteeing that the memory associated with the
4286 * message will not be freed before this call returns.
4287 *
4288 * Return: zero on success, else a negative error code.
4289 */
spi_sync(struct spi_device * spi,struct spi_message * message)4290 int spi_sync(struct spi_device *spi, struct spi_message *message)
4291 {
4292 int ret;
4293
4294 mutex_lock(&spi->controller->bus_lock_mutex);
4295 ret = __spi_sync(spi, message);
4296 mutex_unlock(&spi->controller->bus_lock_mutex);
4297
4298 return ret;
4299 }
4300 EXPORT_SYMBOL_GPL(spi_sync);
4301
4302 /**
4303 * spi_sync_locked - version of spi_sync with exclusive bus usage
4304 * @spi: device with which data will be exchanged
4305 * @message: describes the data transfers
4306 * Context: can sleep
4307 *
4308 * This call may only be used from a context that may sleep. The sleep
4309 * is non-interruptible, and has no timeout. Low-overhead controller
4310 * drivers may DMA directly into and out of the message buffers.
4311 *
4312 * This call should be used by drivers that require exclusive access to the
4313 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
4314 * be released by a spi_bus_unlock call when the exclusive access is over.
4315 *
4316 * Return: zero on success, else a negative error code.
4317 */
spi_sync_locked(struct spi_device * spi,struct spi_message * message)4318 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
4319 {
4320 return __spi_sync(spi, message);
4321 }
4322 EXPORT_SYMBOL_GPL(spi_sync_locked);
4323
4324 /**
4325 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
4326 * @ctlr: SPI bus master that should be locked for exclusive bus access
4327 * Context: can sleep
4328 *
4329 * This call may only be used from a context that may sleep. The sleep
4330 * is non-interruptible, and has no timeout.
4331 *
4332 * This call should be used by drivers that require exclusive access to the
4333 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
4334 * exclusive access is over. Data transfer must be done by spi_sync_locked
4335 * and spi_async_locked calls when the SPI bus lock is held.
4336 *
4337 * Return: always zero.
4338 */
spi_bus_lock(struct spi_controller * ctlr)4339 int spi_bus_lock(struct spi_controller *ctlr)
4340 {
4341 unsigned long flags;
4342
4343 mutex_lock(&ctlr->bus_lock_mutex);
4344
4345 spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
4346 ctlr->bus_lock_flag = 1;
4347 spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
4348
4349 /* Mutex remains locked until spi_bus_unlock() is called */
4350
4351 return 0;
4352 }
4353 EXPORT_SYMBOL_GPL(spi_bus_lock);
4354
4355 /**
4356 * spi_bus_unlock - release the lock for exclusive SPI bus usage
4357 * @ctlr: SPI bus master that was locked for exclusive bus access
4358 * Context: can sleep
4359 *
4360 * This call may only be used from a context that may sleep. The sleep
4361 * is non-interruptible, and has no timeout.
4362 *
4363 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
4364 * call.
4365 *
4366 * Return: always zero.
4367 */
spi_bus_unlock(struct spi_controller * ctlr)4368 int spi_bus_unlock(struct spi_controller *ctlr)
4369 {
4370 ctlr->bus_lock_flag = 0;
4371
4372 mutex_unlock(&ctlr->bus_lock_mutex);
4373
4374 return 0;
4375 }
4376 EXPORT_SYMBOL_GPL(spi_bus_unlock);
4377
4378 /* Portable code must never pass more than 32 bytes */
4379 #define SPI_BUFSIZ max(32, SMP_CACHE_BYTES)
4380
4381 static u8 *buf;
4382
4383 /**
4384 * spi_write_then_read - SPI synchronous write followed by read
4385 * @spi: device with which data will be exchanged
4386 * @txbuf: data to be written (need not be DMA-safe)
4387 * @n_tx: size of txbuf, in bytes
4388 * @rxbuf: buffer into which data will be read (need not be DMA-safe)
4389 * @n_rx: size of rxbuf, in bytes
4390 * Context: can sleep
4391 *
4392 * This performs a half duplex MicroWire style transaction with the
4393 * device, sending txbuf and then reading rxbuf. The return value
4394 * is zero for success, else a negative errno status code.
4395 * This call may only be used from a context that may sleep.
4396 *
4397 * Parameters to this routine are always copied using a small buffer.
4398 * Performance-sensitive or bulk transfer code should instead use
4399 * spi_{async,sync}() calls with DMA-safe buffers.
4400 *
4401 * Return: zero on success, else a negative error code.
4402 */
spi_write_then_read(struct spi_device * spi,const void * txbuf,unsigned n_tx,void * rxbuf,unsigned n_rx)4403 int spi_write_then_read(struct spi_device *spi,
4404 const void *txbuf, unsigned n_tx,
4405 void *rxbuf, unsigned n_rx)
4406 {
4407 static DEFINE_MUTEX(lock);
4408
4409 int status;
4410 struct spi_message message;
4411 struct spi_transfer x[2];
4412 u8 *local_buf;
4413
4414 /*
4415 * Use preallocated DMA-safe buffer if we can. We can't avoid
4416 * copying here, (as a pure convenience thing), but we can
4417 * keep heap costs out of the hot path unless someone else is
4418 * using the pre-allocated buffer or the transfer is too large.
4419 */
4420 if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
4421 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
4422 GFP_KERNEL | GFP_DMA);
4423 if (!local_buf)
4424 return -ENOMEM;
4425 } else {
4426 local_buf = buf;
4427 }
4428
4429 spi_message_init(&message);
4430 memset(x, 0, sizeof(x));
4431 if (n_tx) {
4432 x[0].len = n_tx;
4433 spi_message_add_tail(&x[0], &message);
4434 }
4435 if (n_rx) {
4436 x[1].len = n_rx;
4437 spi_message_add_tail(&x[1], &message);
4438 }
4439
4440 memcpy(local_buf, txbuf, n_tx);
4441 x[0].tx_buf = local_buf;
4442 x[1].rx_buf = local_buf + n_tx;
4443
4444 /* Do the I/O */
4445 status = spi_sync(spi, &message);
4446 if (status == 0)
4447 memcpy(rxbuf, x[1].rx_buf, n_rx);
4448
4449 if (x[0].tx_buf == buf)
4450 mutex_unlock(&lock);
4451 else
4452 kfree(local_buf);
4453
4454 return status;
4455 }
4456 EXPORT_SYMBOL_GPL(spi_write_then_read);
4457
4458 /*-------------------------------------------------------------------------*/
4459
4460 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
4461 /* Must call put_device() when done with returned spi_device device */
of_find_spi_device_by_node(struct device_node * node)4462 static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
4463 {
4464 struct device *dev = bus_find_device_by_of_node(&spi_bus_type, node);
4465
4466 return dev ? to_spi_device(dev) : NULL;
4467 }
4468
4469 /* 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)4470 static struct spi_controller *of_find_spi_controller_by_node(struct device_node *node)
4471 {
4472 struct device *dev;
4473
4474 dev = class_find_device_by_of_node(&spi_master_class, node);
4475 if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
4476 dev = class_find_device_by_of_node(&spi_slave_class, node);
4477 if (!dev)
4478 return NULL;
4479
4480 /* Reference got in class_find_device */
4481 return container_of(dev, struct spi_controller, dev);
4482 }
4483
of_spi_notify(struct notifier_block * nb,unsigned long action,void * arg)4484 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
4485 void *arg)
4486 {
4487 struct of_reconfig_data *rd = arg;
4488 struct spi_controller *ctlr;
4489 struct spi_device *spi;
4490
4491 switch (of_reconfig_get_state_change(action, arg)) {
4492 case OF_RECONFIG_CHANGE_ADD:
4493 ctlr = of_find_spi_controller_by_node(rd->dn->parent);
4494 if (ctlr == NULL)
4495 return NOTIFY_OK; /* Not for us */
4496
4497 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
4498 put_device(&ctlr->dev);
4499 return NOTIFY_OK;
4500 }
4501
4502 /*
4503 * Clear the flag before adding the device so that fw_devlink
4504 * doesn't skip adding consumers to this device.
4505 */
4506 rd->dn->fwnode.flags &= ~FWNODE_FLAG_NOT_DEVICE;
4507 spi = of_register_spi_device(ctlr, rd->dn);
4508 put_device(&ctlr->dev);
4509
4510 if (IS_ERR(spi)) {
4511 pr_err("%s: failed to create for '%pOF'\n",
4512 __func__, rd->dn);
4513 of_node_clear_flag(rd->dn, OF_POPULATED);
4514 return notifier_from_errno(PTR_ERR(spi));
4515 }
4516 break;
4517
4518 case OF_RECONFIG_CHANGE_REMOVE:
4519 /* Already depopulated? */
4520 if (!of_node_check_flag(rd->dn, OF_POPULATED))
4521 return NOTIFY_OK;
4522
4523 /* Find our device by node */
4524 spi = of_find_spi_device_by_node(rd->dn);
4525 if (spi == NULL)
4526 return NOTIFY_OK; /* No? not meant for us */
4527
4528 /* Unregister takes one ref away */
4529 spi_unregister_device(spi);
4530
4531 /* And put the reference of the find */
4532 put_device(&spi->dev);
4533 break;
4534 }
4535
4536 return NOTIFY_OK;
4537 }
4538
4539 static struct notifier_block spi_of_notifier = {
4540 .notifier_call = of_spi_notify,
4541 };
4542 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
4543 extern struct notifier_block spi_of_notifier;
4544 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
4545
4546 #if IS_ENABLED(CONFIG_ACPI)
spi_acpi_controller_match(struct device * dev,const void * data)4547 static int spi_acpi_controller_match(struct device *dev, const void *data)
4548 {
4549 return ACPI_COMPANION(dev->parent) == data;
4550 }
4551
acpi_spi_find_controller_by_adev(struct acpi_device * adev)4552 static struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev)
4553 {
4554 struct device *dev;
4555
4556 dev = class_find_device(&spi_master_class, NULL, adev,
4557 spi_acpi_controller_match);
4558 if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
4559 dev = class_find_device(&spi_slave_class, NULL, adev,
4560 spi_acpi_controller_match);
4561 if (!dev)
4562 return NULL;
4563
4564 return container_of(dev, struct spi_controller, dev);
4565 }
4566
acpi_spi_find_device_by_adev(struct acpi_device * adev)4567 static struct spi_device *acpi_spi_find_device_by_adev(struct acpi_device *adev)
4568 {
4569 struct device *dev;
4570
4571 dev = bus_find_device_by_acpi_dev(&spi_bus_type, adev);
4572 return to_spi_device(dev);
4573 }
4574
acpi_spi_notify(struct notifier_block * nb,unsigned long value,void * arg)4575 static int acpi_spi_notify(struct notifier_block *nb, unsigned long value,
4576 void *arg)
4577 {
4578 struct acpi_device *adev = arg;
4579 struct spi_controller *ctlr;
4580 struct spi_device *spi;
4581
4582 switch (value) {
4583 case ACPI_RECONFIG_DEVICE_ADD:
4584 ctlr = acpi_spi_find_controller_by_adev(acpi_dev_parent(adev));
4585 if (!ctlr)
4586 break;
4587
4588 acpi_register_spi_device(ctlr, adev);
4589 put_device(&ctlr->dev);
4590 break;
4591 case ACPI_RECONFIG_DEVICE_REMOVE:
4592 if (!acpi_device_enumerated(adev))
4593 break;
4594
4595 spi = acpi_spi_find_device_by_adev(adev);
4596 if (!spi)
4597 break;
4598
4599 spi_unregister_device(spi);
4600 put_device(&spi->dev);
4601 break;
4602 }
4603
4604 return NOTIFY_OK;
4605 }
4606
4607 static struct notifier_block spi_acpi_notifier = {
4608 .notifier_call = acpi_spi_notify,
4609 };
4610 #else
4611 extern struct notifier_block spi_acpi_notifier;
4612 #endif
4613
spi_init(void)4614 static int __init spi_init(void)
4615 {
4616 int status;
4617
4618 buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
4619 if (!buf) {
4620 status = -ENOMEM;
4621 goto err0;
4622 }
4623
4624 status = bus_register(&spi_bus_type);
4625 if (status < 0)
4626 goto err1;
4627
4628 status = class_register(&spi_master_class);
4629 if (status < 0)
4630 goto err2;
4631
4632 if (IS_ENABLED(CONFIG_SPI_SLAVE)) {
4633 status = class_register(&spi_slave_class);
4634 if (status < 0)
4635 goto err3;
4636 }
4637
4638 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
4639 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
4640 if (IS_ENABLED(CONFIG_ACPI))
4641 WARN_ON(acpi_reconfig_notifier_register(&spi_acpi_notifier));
4642
4643 return 0;
4644
4645 err3:
4646 class_unregister(&spi_master_class);
4647 err2:
4648 bus_unregister(&spi_bus_type);
4649 err1:
4650 kfree(buf);
4651 buf = NULL;
4652 err0:
4653 return status;
4654 }
4655
4656 /*
4657 * A board_info is normally registered in arch_initcall(),
4658 * but even essential drivers wait till later.
4659 *
4660 * REVISIT only boardinfo really needs static linking. The rest (device and
4661 * driver registration) _could_ be dynamically linked (modular) ... Costs
4662 * include needing to have boardinfo data structures be much more public.
4663 */
4664 postcore_initcall(spi_init);
4665