x86/speculation/mds: Fix documentation typo
[linux/fpc-iii.git] / drivers / amba / bus.c
blob8a99fbe5759fe316974f1c9e25f3615b2c0b1683
1 /*
2 * linux/arch/arm/common/amba.c
4 * Copyright (C) 2003 Deep Blue Solutions Ltd, All Rights Reserved.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10 #include <linux/module.h>
11 #include <linux/init.h>
12 #include <linux/device.h>
13 #include <linux/string.h>
14 #include <linux/slab.h>
15 #include <linux/io.h>
16 #include <linux/pm.h>
17 #include <linux/pm_runtime.h>
18 #include <linux/pm_domain.h>
19 #include <linux/amba/bus.h>
20 #include <linux/sizes.h>
21 #include <linux/limits.h>
22 #include <linux/clk/clk-conf.h>
24 #include <asm/irq.h>
26 #define to_amba_driver(d) container_of(d, struct amba_driver, drv)
28 static const struct amba_id *
29 amba_lookup(const struct amba_id *table, struct amba_device *dev)
31 int ret = 0;
33 while (table->mask) {
34 ret = (dev->periphid & table->mask) == table->id;
35 if (ret)
36 break;
37 table++;
40 return ret ? table : NULL;
43 static int amba_match(struct device *dev, struct device_driver *drv)
45 struct amba_device *pcdev = to_amba_device(dev);
46 struct amba_driver *pcdrv = to_amba_driver(drv);
48 /* When driver_override is set, only bind to the matching driver */
49 if (pcdev->driver_override)
50 return !strcmp(pcdev->driver_override, drv->name);
52 return amba_lookup(pcdrv->id_table, pcdev) != NULL;
55 static int amba_uevent(struct device *dev, struct kobj_uevent_env *env)
57 struct amba_device *pcdev = to_amba_device(dev);
58 int retval = 0;
60 retval = add_uevent_var(env, "AMBA_ID=%08x", pcdev->periphid);
61 if (retval)
62 return retval;
64 retval = add_uevent_var(env, "MODALIAS=amba:d%08X", pcdev->periphid);
65 return retval;
68 static ssize_t driver_override_show(struct device *_dev,
69 struct device_attribute *attr, char *buf)
71 struct amba_device *dev = to_amba_device(_dev);
72 ssize_t len;
74 device_lock(_dev);
75 len = sprintf(buf, "%s\n", dev->driver_override);
76 device_unlock(_dev);
77 return len;
80 static ssize_t driver_override_store(struct device *_dev,
81 struct device_attribute *attr,
82 const char *buf, size_t count)
84 struct amba_device *dev = to_amba_device(_dev);
85 char *driver_override, *old, *cp;
87 /* We need to keep extra room for a newline */
88 if (count >= (PAGE_SIZE - 1))
89 return -EINVAL;
91 driver_override = kstrndup(buf, count, GFP_KERNEL);
92 if (!driver_override)
93 return -ENOMEM;
95 cp = strchr(driver_override, '\n');
96 if (cp)
97 *cp = '\0';
99 device_lock(_dev);
100 old = dev->driver_override;
101 if (strlen(driver_override)) {
102 dev->driver_override = driver_override;
103 } else {
104 kfree(driver_override);
105 dev->driver_override = NULL;
107 device_unlock(_dev);
109 kfree(old);
111 return count;
113 static DEVICE_ATTR_RW(driver_override);
115 #define amba_attr_func(name,fmt,arg...) \
116 static ssize_t name##_show(struct device *_dev, \
117 struct device_attribute *attr, char *buf) \
119 struct amba_device *dev = to_amba_device(_dev); \
120 return sprintf(buf, fmt, arg); \
122 static DEVICE_ATTR_RO(name)
124 amba_attr_func(id, "%08x\n", dev->periphid);
125 amba_attr_func(irq0, "%u\n", dev->irq[0]);
126 amba_attr_func(irq1, "%u\n", dev->irq[1]);
127 amba_attr_func(resource, "\t%016llx\t%016llx\t%016lx\n",
128 (unsigned long long)dev->res.start, (unsigned long long)dev->res.end,
129 dev->res.flags);
131 static struct attribute *amba_dev_attrs[] = {
132 &dev_attr_id.attr,
133 &dev_attr_resource.attr,
134 &dev_attr_driver_override.attr,
135 NULL,
137 ATTRIBUTE_GROUPS(amba_dev);
139 #ifdef CONFIG_PM
141 * Hooks to provide runtime PM of the pclk (bus clock). It is safe to
142 * enable/disable the bus clock at runtime PM suspend/resume as this
143 * does not result in loss of context.
145 static int amba_pm_runtime_suspend(struct device *dev)
147 struct amba_device *pcdev = to_amba_device(dev);
148 int ret = pm_generic_runtime_suspend(dev);
150 if (ret == 0 && dev->driver) {
151 if (pm_runtime_is_irq_safe(dev))
152 clk_disable(pcdev->pclk);
153 else
154 clk_disable_unprepare(pcdev->pclk);
157 return ret;
160 static int amba_pm_runtime_resume(struct device *dev)
162 struct amba_device *pcdev = to_amba_device(dev);
163 int ret;
165 if (dev->driver) {
166 if (pm_runtime_is_irq_safe(dev))
167 ret = clk_enable(pcdev->pclk);
168 else
169 ret = clk_prepare_enable(pcdev->pclk);
170 /* Failure is probably fatal to the system, but... */
171 if (ret)
172 return ret;
175 return pm_generic_runtime_resume(dev);
177 #endif /* CONFIG_PM */
179 static const struct dev_pm_ops amba_pm = {
180 .suspend = pm_generic_suspend,
181 .resume = pm_generic_resume,
182 .freeze = pm_generic_freeze,
183 .thaw = pm_generic_thaw,
184 .poweroff = pm_generic_poweroff,
185 .restore = pm_generic_restore,
186 SET_RUNTIME_PM_OPS(
187 amba_pm_runtime_suspend,
188 amba_pm_runtime_resume,
189 NULL
194 * Primecells are part of the Advanced Microcontroller Bus Architecture,
195 * so we call the bus "amba".
197 struct bus_type amba_bustype = {
198 .name = "amba",
199 .dev_groups = amba_dev_groups,
200 .match = amba_match,
201 .uevent = amba_uevent,
202 .pm = &amba_pm,
205 static int __init amba_init(void)
207 return bus_register(&amba_bustype);
210 postcore_initcall(amba_init);
212 static int amba_get_enable_pclk(struct amba_device *pcdev)
214 int ret;
216 pcdev->pclk = clk_get(&pcdev->dev, "apb_pclk");
217 if (IS_ERR(pcdev->pclk))
218 return PTR_ERR(pcdev->pclk);
220 ret = clk_prepare_enable(pcdev->pclk);
221 if (ret)
222 clk_put(pcdev->pclk);
224 return ret;
227 static void amba_put_disable_pclk(struct amba_device *pcdev)
229 clk_disable_unprepare(pcdev->pclk);
230 clk_put(pcdev->pclk);
234 * These are the device model conversion veneers; they convert the
235 * device model structures to our more specific structures.
237 static int amba_probe(struct device *dev)
239 struct amba_device *pcdev = to_amba_device(dev);
240 struct amba_driver *pcdrv = to_amba_driver(dev->driver);
241 const struct amba_id *id = amba_lookup(pcdrv->id_table, pcdev);
242 int ret;
244 do {
245 ret = of_clk_set_defaults(dev->of_node, false);
246 if (ret < 0)
247 break;
249 ret = dev_pm_domain_attach(dev, true);
250 if (ret == -EPROBE_DEFER)
251 break;
253 ret = amba_get_enable_pclk(pcdev);
254 if (ret) {
255 dev_pm_domain_detach(dev, true);
256 break;
259 pm_runtime_get_noresume(dev);
260 pm_runtime_set_active(dev);
261 pm_runtime_enable(dev);
263 ret = pcdrv->probe(pcdev, id);
264 if (ret == 0)
265 break;
267 pm_runtime_disable(dev);
268 pm_runtime_set_suspended(dev);
269 pm_runtime_put_noidle(dev);
271 amba_put_disable_pclk(pcdev);
272 dev_pm_domain_detach(dev, true);
273 } while (0);
275 return ret;
278 static int amba_remove(struct device *dev)
280 struct amba_device *pcdev = to_amba_device(dev);
281 struct amba_driver *drv = to_amba_driver(dev->driver);
282 int ret;
284 pm_runtime_get_sync(dev);
285 ret = drv->remove(pcdev);
286 pm_runtime_put_noidle(dev);
288 /* Undo the runtime PM settings in amba_probe() */
289 pm_runtime_disable(dev);
290 pm_runtime_set_suspended(dev);
291 pm_runtime_put_noidle(dev);
293 amba_put_disable_pclk(pcdev);
294 dev_pm_domain_detach(dev, true);
296 return ret;
299 static void amba_shutdown(struct device *dev)
301 struct amba_driver *drv = to_amba_driver(dev->driver);
302 drv->shutdown(to_amba_device(dev));
306 * amba_driver_register - register an AMBA device driver
307 * @drv: amba device driver structure
309 * Register an AMBA device driver with the Linux device model
310 * core. If devices pre-exist, the drivers probe function will
311 * be called.
313 int amba_driver_register(struct amba_driver *drv)
315 drv->drv.bus = &amba_bustype;
317 #define SETFN(fn) if (drv->fn) drv->drv.fn = amba_##fn
318 SETFN(probe);
319 SETFN(remove);
320 SETFN(shutdown);
322 return driver_register(&drv->drv);
326 * amba_driver_unregister - remove an AMBA device driver
327 * @drv: AMBA device driver structure to remove
329 * Unregister an AMBA device driver from the Linux device
330 * model. The device model will call the drivers remove function
331 * for each device the device driver is currently handling.
333 void amba_driver_unregister(struct amba_driver *drv)
335 driver_unregister(&drv->drv);
339 static void amba_device_release(struct device *dev)
341 struct amba_device *d = to_amba_device(dev);
343 if (d->res.parent)
344 release_resource(&d->res);
345 kfree(d);
348 static int amba_device_try_add(struct amba_device *dev, struct resource *parent)
350 u32 size;
351 void __iomem *tmp;
352 int i, ret;
354 WARN_ON(dev->irq[0] == (unsigned int)-1);
355 WARN_ON(dev->irq[1] == (unsigned int)-1);
357 ret = request_resource(parent, &dev->res);
358 if (ret)
359 goto err_out;
361 /* Hard-coded primecell ID instead of plug-n-play */
362 if (dev->periphid != 0)
363 goto skip_probe;
366 * Dynamically calculate the size of the resource
367 * and use this for iomap
369 size = resource_size(&dev->res);
370 tmp = ioremap(dev->res.start, size);
371 if (!tmp) {
372 ret = -ENOMEM;
373 goto err_release;
376 ret = dev_pm_domain_attach(&dev->dev, true);
377 if (ret == -EPROBE_DEFER) {
378 iounmap(tmp);
379 goto err_release;
382 ret = amba_get_enable_pclk(dev);
383 if (ret == 0) {
384 u32 pid, cid;
387 * Read pid and cid based on size of resource
388 * they are located at end of region
390 for (pid = 0, i = 0; i < 4; i++)
391 pid |= (readl(tmp + size - 0x20 + 4 * i) & 255) <<
392 (i * 8);
393 for (cid = 0, i = 0; i < 4; i++)
394 cid |= (readl(tmp + size - 0x10 + 4 * i) & 255) <<
395 (i * 8);
397 amba_put_disable_pclk(dev);
399 if (cid == AMBA_CID || cid == CORESIGHT_CID)
400 dev->periphid = pid;
402 if (!dev->periphid)
403 ret = -ENODEV;
406 iounmap(tmp);
407 dev_pm_domain_detach(&dev->dev, true);
409 if (ret)
410 goto err_release;
412 skip_probe:
413 ret = device_add(&dev->dev);
414 if (ret)
415 goto err_release;
417 if (dev->irq[0])
418 ret = device_create_file(&dev->dev, &dev_attr_irq0);
419 if (ret == 0 && dev->irq[1])
420 ret = device_create_file(&dev->dev, &dev_attr_irq1);
421 if (ret == 0)
422 return ret;
424 device_unregister(&dev->dev);
426 err_release:
427 release_resource(&dev->res);
428 err_out:
429 return ret;
433 * Registration of AMBA device require reading its pid and cid registers.
434 * To do this, the device must be turned on (if it is a part of power domain)
435 * and have clocks enabled. However in some cases those resources might not be
436 * yet available. Returning EPROBE_DEFER is not a solution in such case,
437 * because callers don't handle this special error code. Instead such devices
438 * are added to the special list and their registration is retried from
439 * periodic worker, until all resources are available and registration succeeds.
441 struct deferred_device {
442 struct amba_device *dev;
443 struct resource *parent;
444 struct list_head node;
447 static LIST_HEAD(deferred_devices);
448 static DEFINE_MUTEX(deferred_devices_lock);
450 static void amba_deferred_retry_func(struct work_struct *dummy);
451 static DECLARE_DELAYED_WORK(deferred_retry_work, amba_deferred_retry_func);
453 #define DEFERRED_DEVICE_TIMEOUT (msecs_to_jiffies(5 * 1000))
455 static void amba_deferred_retry_func(struct work_struct *dummy)
457 struct deferred_device *ddev, *tmp;
459 mutex_lock(&deferred_devices_lock);
461 list_for_each_entry_safe(ddev, tmp, &deferred_devices, node) {
462 int ret = amba_device_try_add(ddev->dev, ddev->parent);
464 if (ret == -EPROBE_DEFER)
465 continue;
467 list_del_init(&ddev->node);
468 kfree(ddev);
471 if (!list_empty(&deferred_devices))
472 schedule_delayed_work(&deferred_retry_work,
473 DEFERRED_DEVICE_TIMEOUT);
475 mutex_unlock(&deferred_devices_lock);
479 * amba_device_add - add a previously allocated AMBA device structure
480 * @dev: AMBA device allocated by amba_device_alloc
481 * @parent: resource parent for this devices resources
483 * Claim the resource, and read the device cell ID if not already
484 * initialized. Register the AMBA device with the Linux device
485 * manager.
487 int amba_device_add(struct amba_device *dev, struct resource *parent)
489 int ret = amba_device_try_add(dev, parent);
491 if (ret == -EPROBE_DEFER) {
492 struct deferred_device *ddev;
494 ddev = kmalloc(sizeof(*ddev), GFP_KERNEL);
495 if (!ddev)
496 return -ENOMEM;
498 ddev->dev = dev;
499 ddev->parent = parent;
500 ret = 0;
502 mutex_lock(&deferred_devices_lock);
504 if (list_empty(&deferred_devices))
505 schedule_delayed_work(&deferred_retry_work,
506 DEFERRED_DEVICE_TIMEOUT);
507 list_add_tail(&ddev->node, &deferred_devices);
509 mutex_unlock(&deferred_devices_lock);
511 return ret;
513 EXPORT_SYMBOL_GPL(amba_device_add);
515 static struct amba_device *
516 amba_aphb_device_add(struct device *parent, const char *name,
517 resource_size_t base, size_t size, int irq1, int irq2,
518 void *pdata, unsigned int periphid, u64 dma_mask,
519 struct resource *resbase)
521 struct amba_device *dev;
522 int ret;
524 dev = amba_device_alloc(name, base, size);
525 if (!dev)
526 return ERR_PTR(-ENOMEM);
528 dev->dev.coherent_dma_mask = dma_mask;
529 dev->irq[0] = irq1;
530 dev->irq[1] = irq2;
531 dev->periphid = periphid;
532 dev->dev.platform_data = pdata;
533 dev->dev.parent = parent;
535 ret = amba_device_add(dev, resbase);
536 if (ret) {
537 amba_device_put(dev);
538 return ERR_PTR(ret);
541 return dev;
544 struct amba_device *
545 amba_apb_device_add(struct device *parent, const char *name,
546 resource_size_t base, size_t size, int irq1, int irq2,
547 void *pdata, unsigned int periphid)
549 return amba_aphb_device_add(parent, name, base, size, irq1, irq2, pdata,
550 periphid, 0, &iomem_resource);
552 EXPORT_SYMBOL_GPL(amba_apb_device_add);
554 struct amba_device *
555 amba_ahb_device_add(struct device *parent, const char *name,
556 resource_size_t base, size_t size, int irq1, int irq2,
557 void *pdata, unsigned int periphid)
559 return amba_aphb_device_add(parent, name, base, size, irq1, irq2, pdata,
560 periphid, ~0ULL, &iomem_resource);
562 EXPORT_SYMBOL_GPL(amba_ahb_device_add);
564 struct amba_device *
565 amba_apb_device_add_res(struct device *parent, const char *name,
566 resource_size_t base, size_t size, int irq1,
567 int irq2, void *pdata, unsigned int periphid,
568 struct resource *resbase)
570 return amba_aphb_device_add(parent, name, base, size, irq1, irq2, pdata,
571 periphid, 0, resbase);
573 EXPORT_SYMBOL_GPL(amba_apb_device_add_res);
575 struct amba_device *
576 amba_ahb_device_add_res(struct device *parent, const char *name,
577 resource_size_t base, size_t size, int irq1,
578 int irq2, void *pdata, unsigned int periphid,
579 struct resource *resbase)
581 return amba_aphb_device_add(parent, name, base, size, irq1, irq2, pdata,
582 periphid, ~0ULL, resbase);
584 EXPORT_SYMBOL_GPL(amba_ahb_device_add_res);
587 static void amba_device_initialize(struct amba_device *dev, const char *name)
589 device_initialize(&dev->dev);
590 if (name)
591 dev_set_name(&dev->dev, "%s", name);
592 dev->dev.release = amba_device_release;
593 dev->dev.bus = &amba_bustype;
594 dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
595 dev->res.name = dev_name(&dev->dev);
599 * amba_device_alloc - allocate an AMBA device
600 * @name: sysfs name of the AMBA device
601 * @base: base of AMBA device
602 * @size: size of AMBA device
604 * Allocate and initialize an AMBA device structure. Returns %NULL
605 * on failure.
607 struct amba_device *amba_device_alloc(const char *name, resource_size_t base,
608 size_t size)
610 struct amba_device *dev;
612 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
613 if (dev) {
614 amba_device_initialize(dev, name);
615 dev->res.start = base;
616 dev->res.end = base + size - 1;
617 dev->res.flags = IORESOURCE_MEM;
620 return dev;
622 EXPORT_SYMBOL_GPL(amba_device_alloc);
625 * amba_device_register - register an AMBA device
626 * @dev: AMBA device to register
627 * @parent: parent memory resource
629 * Setup the AMBA device, reading the cell ID if present.
630 * Claim the resource, and register the AMBA device with
631 * the Linux device manager.
633 int amba_device_register(struct amba_device *dev, struct resource *parent)
635 amba_device_initialize(dev, dev->dev.init_name);
636 dev->dev.init_name = NULL;
638 return amba_device_add(dev, parent);
642 * amba_device_put - put an AMBA device
643 * @dev: AMBA device to put
645 void amba_device_put(struct amba_device *dev)
647 put_device(&dev->dev);
649 EXPORT_SYMBOL_GPL(amba_device_put);
652 * amba_device_unregister - unregister an AMBA device
653 * @dev: AMBA device to remove
655 * Remove the specified AMBA device from the Linux device
656 * manager. All files associated with this object will be
657 * destroyed, and device drivers notified that the device has
658 * been removed. The AMBA device's resources including
659 * the amba_device structure will be freed once all
660 * references to it have been dropped.
662 void amba_device_unregister(struct amba_device *dev)
664 device_unregister(&dev->dev);
668 struct find_data {
669 struct amba_device *dev;
670 struct device *parent;
671 const char *busid;
672 unsigned int id;
673 unsigned int mask;
676 static int amba_find_match(struct device *dev, void *data)
678 struct find_data *d = data;
679 struct amba_device *pcdev = to_amba_device(dev);
680 int r;
682 r = (pcdev->periphid & d->mask) == d->id;
683 if (d->parent)
684 r &= d->parent == dev->parent;
685 if (d->busid)
686 r &= strcmp(dev_name(dev), d->busid) == 0;
688 if (r) {
689 get_device(dev);
690 d->dev = pcdev;
693 return r;
697 * amba_find_device - locate an AMBA device given a bus id
698 * @busid: bus id for device (or NULL)
699 * @parent: parent device (or NULL)
700 * @id: peripheral ID (or 0)
701 * @mask: peripheral ID mask (or 0)
703 * Return the AMBA device corresponding to the supplied parameters.
704 * If no device matches, returns NULL.
706 * NOTE: When a valid device is found, its refcount is
707 * incremented, and must be decremented before the returned
708 * reference.
710 struct amba_device *
711 amba_find_device(const char *busid, struct device *parent, unsigned int id,
712 unsigned int mask)
714 struct find_data data;
716 data.dev = NULL;
717 data.parent = parent;
718 data.busid = busid;
719 data.id = id;
720 data.mask = mask;
722 bus_for_each_dev(&amba_bustype, NULL, &data, amba_find_match);
724 return data.dev;
728 * amba_request_regions - request all mem regions associated with device
729 * @dev: amba_device structure for device
730 * @name: name, or NULL to use driver name
732 int amba_request_regions(struct amba_device *dev, const char *name)
734 int ret = 0;
735 u32 size;
737 if (!name)
738 name = dev->dev.driver->name;
740 size = resource_size(&dev->res);
742 if (!request_mem_region(dev->res.start, size, name))
743 ret = -EBUSY;
745 return ret;
749 * amba_release_regions - release mem regions associated with device
750 * @dev: amba_device structure for device
752 * Release regions claimed by a successful call to amba_request_regions.
754 void amba_release_regions(struct amba_device *dev)
756 u32 size;
758 size = resource_size(&dev->res);
759 release_mem_region(dev->res.start, size);
762 EXPORT_SYMBOL(amba_driver_register);
763 EXPORT_SYMBOL(amba_driver_unregister);
764 EXPORT_SYMBOL(amba_device_register);
765 EXPORT_SYMBOL(amba_device_unregister);
766 EXPORT_SYMBOL(amba_find_device);
767 EXPORT_SYMBOL(amba_request_regions);
768 EXPORT_SYMBOL(amba_release_regions);