1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  linux/arch/arm/common/amba.c
4  *
5  *  Copyright (C) 2003 Deep Blue Solutions Ltd, All Rights Reserved.
6  */
7 #include <linux/module.h>
8 #include <linux/init.h>
9 #include <linux/device.h>
10 #include <linux/string.h>
11 #include <linux/slab.h>
12 #include <linux/io.h>
13 #include <linux/pm.h>
14 #include <linux/pm_runtime.h>
15 #include <linux/pm_domain.h>
16 #include <linux/amba/bus.h>
17 #include <linux/sizes.h>
18 #include <linux/limits.h>
19 #include <linux/clk/clk-conf.h>
20 #include <linux/platform_device.h>
21 #include <linux/reset.h>
22 #include <linux/of_irq.h>
23 #include <linux/of_device.h>
24 #include <linux/acpi.h>
25 #include <linux/iommu.h>
26 #include <linux/dma-map-ops.h>
27 
28 #define to_amba_driver(d)	container_of(d, struct amba_driver, drv)
29 
30 /* called on periphid match and class 0x9 coresight device. */
31 static int
amba_cs_uci_id_match(const struct amba_id * table,struct amba_device * dev)32 amba_cs_uci_id_match(const struct amba_id *table, struct amba_device *dev)
33 {
34 	int ret = 0;
35 	struct amba_cs_uci_id *uci;
36 
37 	uci = table->data;
38 
39 	/* no table data or zero mask - return match on periphid */
40 	if (!uci || (uci->devarch_mask == 0))
41 		return 1;
42 
43 	/* test against read devtype and masked devarch value */
44 	ret = (dev->uci.devtype == uci->devtype) &&
45 		((dev->uci.devarch & uci->devarch_mask) == uci->devarch);
46 	return ret;
47 }
48 
49 static const struct amba_id *
amba_lookup(const struct amba_id * table,struct amba_device * dev)50 amba_lookup(const struct amba_id *table, struct amba_device *dev)
51 {
52 	while (table->mask) {
53 		if (((dev->periphid & table->mask) == table->id) &&
54 			((dev->cid != CORESIGHT_CID) ||
55 			 (amba_cs_uci_id_match(table, dev))))
56 			return table;
57 		table++;
58 	}
59 	return NULL;
60 }
61 
amba_get_enable_pclk(struct amba_device * pcdev)62 static int amba_get_enable_pclk(struct amba_device *pcdev)
63 {
64 	int ret;
65 
66 	pcdev->pclk = clk_get(&pcdev->dev, "apb_pclk");
67 	if (IS_ERR(pcdev->pclk))
68 		return PTR_ERR(pcdev->pclk);
69 
70 	ret = clk_prepare_enable(pcdev->pclk);
71 	if (ret)
72 		clk_put(pcdev->pclk);
73 
74 	return ret;
75 }
76 
amba_put_disable_pclk(struct amba_device * pcdev)77 static void amba_put_disable_pclk(struct amba_device *pcdev)
78 {
79 	clk_disable_unprepare(pcdev->pclk);
80 	clk_put(pcdev->pclk);
81 }
82 
83 
driver_override_show(struct device * _dev,struct device_attribute * attr,char * buf)84 static ssize_t driver_override_show(struct device *_dev,
85 				    struct device_attribute *attr, char *buf)
86 {
87 	struct amba_device *dev = to_amba_device(_dev);
88 	ssize_t len;
89 
90 	device_lock(_dev);
91 	len = sprintf(buf, "%s\n", dev->driver_override);
92 	device_unlock(_dev);
93 	return len;
94 }
95 
driver_override_store(struct device * _dev,struct device_attribute * attr,const char * buf,size_t count)96 static ssize_t driver_override_store(struct device *_dev,
97 				     struct device_attribute *attr,
98 				     const char *buf, size_t count)
99 {
100 	struct amba_device *dev = to_amba_device(_dev);
101 	int ret;
102 
103 	ret = driver_set_override(_dev, &dev->driver_override, buf, count);
104 	if (ret)
105 		return ret;
106 
107 	return count;
108 }
109 static DEVICE_ATTR_RW(driver_override);
110 
111 #define amba_attr_func(name,fmt,arg...)					\
112 static ssize_t name##_show(struct device *_dev,				\
113 			   struct device_attribute *attr, char *buf)	\
114 {									\
115 	struct amba_device *dev = to_amba_device(_dev);			\
116 	return sprintf(buf, fmt, arg);					\
117 }									\
118 static DEVICE_ATTR_RO(name)
119 
120 amba_attr_func(id, "%08x\n", dev->periphid);
121 amba_attr_func(resource, "\t%016llx\t%016llx\t%016lx\n",
122 	 (unsigned long long)dev->res.start, (unsigned long long)dev->res.end,
123 	 dev->res.flags);
124 
125 static struct attribute *amba_dev_attrs[] = {
126 	&dev_attr_id.attr,
127 	&dev_attr_resource.attr,
128 	&dev_attr_driver_override.attr,
129 	NULL,
130 };
131 ATTRIBUTE_GROUPS(amba_dev);
132 
amba_match(struct device * dev,struct device_driver * drv)133 static int amba_match(struct device *dev, struct device_driver *drv)
134 {
135 	struct amba_device *pcdev = to_amba_device(dev);
136 	struct amba_driver *pcdrv = to_amba_driver(drv);
137 
138 	/* When driver_override is set, only bind to the matching driver */
139 	if (pcdev->driver_override)
140 		return !strcmp(pcdev->driver_override, drv->name);
141 
142 	return amba_lookup(pcdrv->id_table, pcdev) != NULL;
143 }
144 
amba_uevent(struct device * dev,struct kobj_uevent_env * env)145 static int amba_uevent(struct device *dev, struct kobj_uevent_env *env)
146 {
147 	struct amba_device *pcdev = to_amba_device(dev);
148 	int retval = 0;
149 
150 	retval = add_uevent_var(env, "AMBA_ID=%08x", pcdev->periphid);
151 	if (retval)
152 		return retval;
153 
154 	retval = add_uevent_var(env, "MODALIAS=amba:d%08X", pcdev->periphid);
155 	return retval;
156 }
157 
of_amba_device_decode_irq(struct amba_device * dev)158 static int of_amba_device_decode_irq(struct amba_device *dev)
159 {
160 	struct device_node *node = dev->dev.of_node;
161 	int i, irq = 0;
162 
163 	if (IS_ENABLED(CONFIG_OF_IRQ) && node) {
164 		/* Decode the IRQs and address ranges */
165 		for (i = 0; i < AMBA_NR_IRQS; i++) {
166 			irq = of_irq_get(node, i);
167 			if (irq < 0) {
168 				if (irq == -EPROBE_DEFER)
169 					return irq;
170 				irq = 0;
171 			}
172 
173 			dev->irq[i] = irq;
174 		}
175 	}
176 
177 	return 0;
178 }
179 
180 /*
181  * These are the device model conversion veneers; they convert the
182  * device model structures to our more specific structures.
183  */
amba_probe(struct device * dev)184 static int amba_probe(struct device *dev)
185 {
186 	struct amba_device *pcdev = to_amba_device(dev);
187 	struct amba_driver *pcdrv = to_amba_driver(dev->driver);
188 	const struct amba_id *id = amba_lookup(pcdrv->id_table, pcdev);
189 	int ret;
190 
191 	do {
192 		ret = of_amba_device_decode_irq(pcdev);
193 		if (ret)
194 			break;
195 
196 		ret = of_clk_set_defaults(dev->of_node, false);
197 		if (ret < 0)
198 			break;
199 
200 		ret = dev_pm_domain_attach(dev, true);
201 		if (ret)
202 			break;
203 
204 		ret = amba_get_enable_pclk(pcdev);
205 		if (ret) {
206 			dev_pm_domain_detach(dev, true);
207 			break;
208 		}
209 
210 		pm_runtime_get_noresume(dev);
211 		pm_runtime_set_active(dev);
212 		pm_runtime_enable(dev);
213 
214 		ret = pcdrv->probe(pcdev, id);
215 		if (ret == 0)
216 			break;
217 
218 		pm_runtime_disable(dev);
219 		pm_runtime_set_suspended(dev);
220 		pm_runtime_put_noidle(dev);
221 
222 		amba_put_disable_pclk(pcdev);
223 		dev_pm_domain_detach(dev, true);
224 	} while (0);
225 
226 	return ret;
227 }
228 
amba_remove(struct device * dev)229 static void amba_remove(struct device *dev)
230 {
231 	struct amba_device *pcdev = to_amba_device(dev);
232 	struct amba_driver *drv = to_amba_driver(dev->driver);
233 
234 	pm_runtime_get_sync(dev);
235 	if (drv->remove)
236 		drv->remove(pcdev);
237 	pm_runtime_put_noidle(dev);
238 
239 	/* Undo the runtime PM settings in amba_probe() */
240 	pm_runtime_disable(dev);
241 	pm_runtime_set_suspended(dev);
242 	pm_runtime_put_noidle(dev);
243 
244 	amba_put_disable_pclk(pcdev);
245 	dev_pm_domain_detach(dev, true);
246 }
247 
amba_shutdown(struct device * dev)248 static void amba_shutdown(struct device *dev)
249 {
250 	struct amba_driver *drv;
251 
252 	if (!dev->driver)
253 		return;
254 
255 	drv = to_amba_driver(dev->driver);
256 	if (drv->shutdown)
257 		drv->shutdown(to_amba_device(dev));
258 }
259 
amba_dma_configure(struct device * dev)260 static int amba_dma_configure(struct device *dev)
261 {
262 	struct amba_driver *drv = to_amba_driver(dev->driver);
263 	enum dev_dma_attr attr;
264 	int ret = 0;
265 
266 	if (dev->of_node) {
267 		ret = of_dma_configure(dev, dev->of_node, true);
268 	} else if (has_acpi_companion(dev)) {
269 		attr = acpi_get_dma_attr(to_acpi_device_node(dev->fwnode));
270 		ret = acpi_dma_configure(dev, attr);
271 	}
272 
273 	if (!ret && !drv->driver_managed_dma) {
274 		ret = iommu_device_use_default_domain(dev);
275 		if (ret)
276 			arch_teardown_dma_ops(dev);
277 	}
278 
279 	return ret;
280 }
281 
amba_dma_cleanup(struct device * dev)282 static void amba_dma_cleanup(struct device *dev)
283 {
284 	struct amba_driver *drv = to_amba_driver(dev->driver);
285 
286 	if (!drv->driver_managed_dma)
287 		iommu_device_unuse_default_domain(dev);
288 }
289 
290 #ifdef CONFIG_PM
291 /*
292  * Hooks to provide runtime PM of the pclk (bus clock).  It is safe to
293  * enable/disable the bus clock at runtime PM suspend/resume as this
294  * does not result in loss of context.
295  */
amba_pm_runtime_suspend(struct device * dev)296 static int amba_pm_runtime_suspend(struct device *dev)
297 {
298 	struct amba_device *pcdev = to_amba_device(dev);
299 	int ret = pm_generic_runtime_suspend(dev);
300 
301 	if (ret == 0 && dev->driver) {
302 		if (pm_runtime_is_irq_safe(dev))
303 			clk_disable(pcdev->pclk);
304 		else
305 			clk_disable_unprepare(pcdev->pclk);
306 	}
307 
308 	return ret;
309 }
310 
amba_pm_runtime_resume(struct device * dev)311 static int amba_pm_runtime_resume(struct device *dev)
312 {
313 	struct amba_device *pcdev = to_amba_device(dev);
314 	int ret;
315 
316 	if (dev->driver) {
317 		if (pm_runtime_is_irq_safe(dev))
318 			ret = clk_enable(pcdev->pclk);
319 		else
320 			ret = clk_prepare_enable(pcdev->pclk);
321 		/* Failure is probably fatal to the system, but... */
322 		if (ret)
323 			return ret;
324 	}
325 
326 	return pm_generic_runtime_resume(dev);
327 }
328 #endif /* CONFIG_PM */
329 
330 static const struct dev_pm_ops amba_pm = {
331 	.suspend	= pm_generic_suspend,
332 	.resume		= pm_generic_resume,
333 	.freeze		= pm_generic_freeze,
334 	.thaw		= pm_generic_thaw,
335 	.poweroff	= pm_generic_poweroff,
336 	.restore	= pm_generic_restore,
337 	SET_RUNTIME_PM_OPS(
338 		amba_pm_runtime_suspend,
339 		amba_pm_runtime_resume,
340 		NULL
341 	)
342 };
343 
344 /*
345  * Primecells are part of the Advanced Microcontroller Bus Architecture,
346  * so we call the bus "amba".
347  * DMA configuration for platform and AMBA bus is same. So here we reuse
348  * platform's DMA config routine.
349  */
350 struct bus_type amba_bustype = {
351 	.name		= "amba",
352 	.dev_groups	= amba_dev_groups,
353 	.match		= amba_match,
354 	.uevent		= amba_uevent,
355 	.probe		= amba_probe,
356 	.remove		= amba_remove,
357 	.shutdown	= amba_shutdown,
358 	.dma_configure	= amba_dma_configure,
359 	.dma_cleanup	= amba_dma_cleanup,
360 	.pm		= &amba_pm,
361 };
362 EXPORT_SYMBOL_GPL(amba_bustype);
363 
amba_init(void)364 static int __init amba_init(void)
365 {
366 	return bus_register(&amba_bustype);
367 }
368 
369 postcore_initcall(amba_init);
370 
371 /**
372  *	amba_driver_register - register an AMBA device driver
373  *	@drv: amba device driver structure
374  *
375  *	Register an AMBA device driver with the Linux device model
376  *	core.  If devices pre-exist, the drivers probe function will
377  *	be called.
378  */
amba_driver_register(struct amba_driver * drv)379 int amba_driver_register(struct amba_driver *drv)
380 {
381 	if (!drv->probe)
382 		return -EINVAL;
383 
384 	drv->drv.bus = &amba_bustype;
385 
386 	return driver_register(&drv->drv);
387 }
388 EXPORT_SYMBOL(amba_driver_register);
389 
390 /**
391  *	amba_driver_unregister - remove an AMBA device driver
392  *	@drv: AMBA device driver structure to remove
393  *
394  *	Unregister an AMBA device driver from the Linux device
395  *	model.  The device model will call the drivers remove function
396  *	for each device the device driver is currently handling.
397  */
amba_driver_unregister(struct amba_driver * drv)398 void amba_driver_unregister(struct amba_driver *drv)
399 {
400 	driver_unregister(&drv->drv);
401 }
402 EXPORT_SYMBOL(amba_driver_unregister);
403 
amba_device_release(struct device * dev)404 static void amba_device_release(struct device *dev)
405 {
406 	struct amba_device *d = to_amba_device(dev);
407 
408 	if (d->res.parent)
409 		release_resource(&d->res);
410 	kfree(d);
411 }
412 
amba_read_periphid(struct amba_device * dev)413 static int amba_read_periphid(struct amba_device *dev)
414 {
415 	struct reset_control *rstc;
416 	u32 size, pid, cid;
417 	void __iomem *tmp;
418 	int i, ret;
419 
420 	ret = dev_pm_domain_attach(&dev->dev, true);
421 	if (ret)
422 		goto err_out;
423 
424 	ret = amba_get_enable_pclk(dev);
425 	if (ret)
426 		goto err_pm;
427 
428 	/*
429 	 * Find reset control(s) of the amba bus and de-assert them.
430 	 */
431 	rstc = of_reset_control_array_get_optional_shared(dev->dev.of_node);
432 	if (IS_ERR(rstc)) {
433 		ret = PTR_ERR(rstc);
434 		if (ret != -EPROBE_DEFER)
435 			dev_err(&dev->dev, "can't get reset: %d\n", ret);
436 		goto err_clk;
437 	}
438 	reset_control_deassert(rstc);
439 	reset_control_put(rstc);
440 
441 	size = resource_size(&dev->res);
442 	tmp = ioremap(dev->res.start, size);
443 	if (!tmp) {
444 		ret = -ENOMEM;
445 		goto err_clk;
446 	}
447 
448 	/*
449 	 * Read pid and cid based on size of resource
450 	 * they are located at end of region
451 	 */
452 	for (pid = 0, i = 0; i < 4; i++)
453 		pid |= (readl(tmp + size - 0x20 + 4 * i) & 255) << (i * 8);
454 	for (cid = 0, i = 0; i < 4; i++)
455 		cid |= (readl(tmp + size - 0x10 + 4 * i) & 255) << (i * 8);
456 
457 	if (cid == CORESIGHT_CID) {
458 		/* set the base to the start of the last 4k block */
459 		void __iomem *csbase = tmp + size - 4096;
460 
461 		dev->uci.devarch = readl(csbase + UCI_REG_DEVARCH_OFFSET);
462 		dev->uci.devtype = readl(csbase + UCI_REG_DEVTYPE_OFFSET) & 0xff;
463 	}
464 
465 	if (cid == AMBA_CID || cid == CORESIGHT_CID) {
466 		dev->periphid = pid;
467 		dev->cid = cid;
468 	}
469 
470 	if (!dev->periphid)
471 		ret = -ENODEV;
472 
473 	iounmap(tmp);
474 
475 err_clk:
476 	amba_put_disable_pclk(dev);
477 err_pm:
478 	dev_pm_domain_detach(&dev->dev, true);
479 err_out:
480 	return ret;
481 }
482 
amba_device_try_add(struct amba_device * dev,struct resource * parent)483 static int amba_device_try_add(struct amba_device *dev, struct resource *parent)
484 {
485 	int ret;
486 
487 	ret = request_resource(parent, &dev->res);
488 	if (ret)
489 		goto err_out;
490 
491 	/* Hard-coded primecell ID instead of plug-n-play */
492 	if (dev->periphid != 0)
493 		goto skip_probe;
494 
495 	ret = amba_read_periphid(dev);
496 	if (ret)
497 		goto err_release;
498 
499 skip_probe:
500 	ret = device_add(&dev->dev);
501 err_release:
502 	if (ret)
503 		release_resource(&dev->res);
504 err_out:
505 	return ret;
506 }
507 
508 /*
509  * Registration of AMBA device require reading its pid and cid registers.
510  * To do this, the device must be turned on (if it is a part of power domain)
511  * and have clocks enabled. However in some cases those resources might not be
512  * yet available. Returning EPROBE_DEFER is not a solution in such case,
513  * because callers don't handle this special error code. Instead such devices
514  * are added to the special list and their registration is retried from
515  * periodic worker, until all resources are available and registration succeeds.
516  */
517 struct deferred_device {
518 	struct amba_device *dev;
519 	struct resource *parent;
520 	struct list_head node;
521 };
522 
523 static LIST_HEAD(deferred_devices);
524 static DEFINE_MUTEX(deferred_devices_lock);
525 
526 static void amba_deferred_retry_func(struct work_struct *dummy);
527 static DECLARE_DELAYED_WORK(deferred_retry_work, amba_deferred_retry_func);
528 
529 #define DEFERRED_DEVICE_TIMEOUT (msecs_to_jiffies(5 * 1000))
530 
amba_deferred_retry(void)531 static int amba_deferred_retry(void)
532 {
533 	struct deferred_device *ddev, *tmp;
534 
535 	mutex_lock(&deferred_devices_lock);
536 
537 	list_for_each_entry_safe(ddev, tmp, &deferred_devices, node) {
538 		int ret = amba_device_try_add(ddev->dev, ddev->parent);
539 
540 		if (ret == -EPROBE_DEFER)
541 			continue;
542 
543 		list_del_init(&ddev->node);
544 		amba_device_put(ddev->dev);
545 		kfree(ddev);
546 	}
547 
548 	mutex_unlock(&deferred_devices_lock);
549 
550 	return 0;
551 }
552 late_initcall(amba_deferred_retry);
553 
amba_deferred_retry_func(struct work_struct * dummy)554 static void amba_deferred_retry_func(struct work_struct *dummy)
555 {
556 	amba_deferred_retry();
557 
558 	if (!list_empty(&deferred_devices))
559 		schedule_delayed_work(&deferred_retry_work,
560 				      DEFERRED_DEVICE_TIMEOUT);
561 }
562 
563 /**
564  *	amba_device_add - add a previously allocated AMBA device structure
565  *	@dev: AMBA device allocated by amba_device_alloc
566  *	@parent: resource parent for this devices resources
567  *
568  *	Claim the resource, and read the device cell ID if not already
569  *	initialized.  Register the AMBA device with the Linux device
570  *	manager.
571  */
amba_device_add(struct amba_device * dev,struct resource * parent)572 int amba_device_add(struct amba_device *dev, struct resource *parent)
573 {
574 	int ret = amba_device_try_add(dev, parent);
575 
576 	if (ret == -EPROBE_DEFER) {
577 		struct deferred_device *ddev;
578 
579 		ddev = kmalloc(sizeof(*ddev), GFP_KERNEL);
580 		if (!ddev)
581 			return -ENOMEM;
582 
583 		ddev->dev = dev;
584 		ddev->parent = parent;
585 		ret = 0;
586 
587 		mutex_lock(&deferred_devices_lock);
588 
589 		if (list_empty(&deferred_devices))
590 			schedule_delayed_work(&deferred_retry_work,
591 					      DEFERRED_DEVICE_TIMEOUT);
592 		list_add_tail(&ddev->node, &deferred_devices);
593 
594 		mutex_unlock(&deferred_devices_lock);
595 	}
596 	return ret;
597 }
598 EXPORT_SYMBOL_GPL(amba_device_add);
599 
amba_device_initialize(struct amba_device * dev,const char * name)600 static void amba_device_initialize(struct amba_device *dev, const char *name)
601 {
602 	device_initialize(&dev->dev);
603 	if (name)
604 		dev_set_name(&dev->dev, "%s", name);
605 	dev->dev.release = amba_device_release;
606 	dev->dev.bus = &amba_bustype;
607 	dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
608 	dev->dev.dma_parms = &dev->dma_parms;
609 	dev->res.name = dev_name(&dev->dev);
610 }
611 
612 /**
613  *	amba_device_alloc - allocate an AMBA device
614  *	@name: sysfs name of the AMBA device
615  *	@base: base of AMBA device
616  *	@size: size of AMBA device
617  *
618  *	Allocate and initialize an AMBA device structure.  Returns %NULL
619  *	on failure.
620  */
amba_device_alloc(const char * name,resource_size_t base,size_t size)621 struct amba_device *amba_device_alloc(const char *name, resource_size_t base,
622 	size_t size)
623 {
624 	struct amba_device *dev;
625 
626 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
627 	if (dev) {
628 		amba_device_initialize(dev, name);
629 		dev->res.start = base;
630 		dev->res.end = base + size - 1;
631 		dev->res.flags = IORESOURCE_MEM;
632 	}
633 
634 	return dev;
635 }
636 EXPORT_SYMBOL_GPL(amba_device_alloc);
637 
638 /**
639  *	amba_device_register - register an AMBA device
640  *	@dev: AMBA device to register
641  *	@parent: parent memory resource
642  *
643  *	Setup the AMBA device, reading the cell ID if present.
644  *	Claim the resource, and register the AMBA device with
645  *	the Linux device manager.
646  */
amba_device_register(struct amba_device * dev,struct resource * parent)647 int amba_device_register(struct amba_device *dev, struct resource *parent)
648 {
649 	amba_device_initialize(dev, dev->dev.init_name);
650 	dev->dev.init_name = NULL;
651 
652 	return amba_device_add(dev, parent);
653 }
654 EXPORT_SYMBOL(amba_device_register);
655 
656 /**
657  *	amba_device_put - put an AMBA device
658  *	@dev: AMBA device to put
659  */
amba_device_put(struct amba_device * dev)660 void amba_device_put(struct amba_device *dev)
661 {
662 	put_device(&dev->dev);
663 }
664 EXPORT_SYMBOL_GPL(amba_device_put);
665 
666 /**
667  *	amba_device_unregister - unregister an AMBA device
668  *	@dev: AMBA device to remove
669  *
670  *	Remove the specified AMBA device from the Linux device
671  *	manager.  All files associated with this object will be
672  *	destroyed, and device drivers notified that the device has
673  *	been removed.  The AMBA device's resources including
674  *	the amba_device structure will be freed once all
675  *	references to it have been dropped.
676  */
amba_device_unregister(struct amba_device * dev)677 void amba_device_unregister(struct amba_device *dev)
678 {
679 	device_unregister(&dev->dev);
680 }
681 EXPORT_SYMBOL(amba_device_unregister);
682 
683 /**
684  *	amba_request_regions - request all mem regions associated with device
685  *	@dev: amba_device structure for device
686  *	@name: name, or NULL to use driver name
687  */
amba_request_regions(struct amba_device * dev,const char * name)688 int amba_request_regions(struct amba_device *dev, const char *name)
689 {
690 	int ret = 0;
691 	u32 size;
692 
693 	if (!name)
694 		name = dev->dev.driver->name;
695 
696 	size = resource_size(&dev->res);
697 
698 	if (!request_mem_region(dev->res.start, size, name))
699 		ret = -EBUSY;
700 
701 	return ret;
702 }
703 EXPORT_SYMBOL(amba_request_regions);
704 
705 /**
706  *	amba_release_regions - release mem regions associated with device
707  *	@dev: amba_device structure for device
708  *
709  *	Release regions claimed by a successful call to amba_request_regions.
710  */
amba_release_regions(struct amba_device * dev)711 void amba_release_regions(struct amba_device *dev)
712 {
713 	u32 size;
714 
715 	size = resource_size(&dev->res);
716 	release_mem_region(dev->res.start, size);
717 }
718 EXPORT_SYMBOL(amba_release_regions);
719