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.
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>
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>
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)
34 ret = (dev->periphid & table->mask) == table->id;
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);
60 retval = add_uevent_var(env, "AMBA_ID=%08x", pcdev->periphid);
64 retval = add_uevent_var(env, "MODALIAS=amba:d%08X", pcdev->periphid);
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);
74 if (!dev->driver_override)
78 len = sprintf(buf, "%s\n", dev->driver_override);
83 static ssize_t driver_override_store(struct device *_dev,
84 struct device_attribute *attr,
85 const char *buf, size_t count)
87 struct amba_device *dev = to_amba_device(_dev);
88 char *driver_override, *old, *cp;
93 driver_override = kstrndup(buf, count, GFP_KERNEL);
97 cp = strchr(driver_override, '\n');
102 old = dev->driver_override;
103 if (strlen(driver_override)) {
104 dev->driver_override = driver_override;
106 kfree(driver_override);
107 dev->driver_override = NULL;
115 static DEVICE_ATTR_RW(driver_override);
117 #define amba_attr_func(name,fmt,arg...) \
118 static ssize_t name##_show(struct device *_dev, \
119 struct device_attribute *attr, char *buf) \
121 struct amba_device *dev = to_amba_device(_dev); \
122 return sprintf(buf, fmt, arg); \
124 static DEVICE_ATTR_RO(name)
126 amba_attr_func(id, "%08x\n", dev->periphid);
127 amba_attr_func(irq0, "%u\n", dev->irq[0]);
128 amba_attr_func(irq1, "%u\n", dev->irq[1]);
129 amba_attr_func(resource, "\t%016llx\t%016llx\t%016lx\n",
130 (unsigned long long)dev->res.start, (unsigned long long)dev->res.end,
133 static struct attribute *amba_dev_attrs[] = {
135 &dev_attr_resource.attr,
136 &dev_attr_driver_override.attr,
139 ATTRIBUTE_GROUPS(amba_dev);
143 * Hooks to provide runtime PM of the pclk (bus clock). It is safe to
144 * enable/disable the bus clock at runtime PM suspend/resume as this
145 * does not result in loss of context.
147 static int amba_pm_runtime_suspend(struct device *dev)
149 struct amba_device *pcdev = to_amba_device(dev);
150 int ret = pm_generic_runtime_suspend(dev);
152 if (ret == 0 && dev->driver) {
153 if (pm_runtime_is_irq_safe(dev))
154 clk_disable(pcdev->pclk);
156 clk_disable_unprepare(pcdev->pclk);
162 static int amba_pm_runtime_resume(struct device *dev)
164 struct amba_device *pcdev = to_amba_device(dev);
168 if (pm_runtime_is_irq_safe(dev))
169 ret = clk_enable(pcdev->pclk);
171 ret = clk_prepare_enable(pcdev->pclk);
172 /* Failure is probably fatal to the system, but... */
177 return pm_generic_runtime_resume(dev);
179 #endif /* CONFIG_PM */
181 static const struct dev_pm_ops amba_pm = {
182 .suspend = pm_generic_suspend,
183 .resume = pm_generic_resume,
184 .freeze = pm_generic_freeze,
185 .thaw = pm_generic_thaw,
186 .poweroff = pm_generic_poweroff,
187 .restore = pm_generic_restore,
189 amba_pm_runtime_suspend,
190 amba_pm_runtime_resume,
196 * Primecells are part of the Advanced Microcontroller Bus Architecture,
197 * so we call the bus "amba".
199 struct bus_type amba_bustype = {
201 .dev_groups = amba_dev_groups,
203 .uevent = amba_uevent,
208 static int __init amba_init(void)
210 return bus_register(&amba_bustype);
213 postcore_initcall(amba_init);
215 static int amba_get_enable_pclk(struct amba_device *pcdev)
219 pcdev->pclk = clk_get(&pcdev->dev, "apb_pclk");
220 if (IS_ERR(pcdev->pclk))
221 return PTR_ERR(pcdev->pclk);
223 ret = clk_prepare_enable(pcdev->pclk);
225 clk_put(pcdev->pclk);
230 static void amba_put_disable_pclk(struct amba_device *pcdev)
232 clk_disable_unprepare(pcdev->pclk);
233 clk_put(pcdev->pclk);
237 * These are the device model conversion veneers; they convert the
238 * device model structures to our more specific structures.
240 static int amba_probe(struct device *dev)
242 struct amba_device *pcdev = to_amba_device(dev);
243 struct amba_driver *pcdrv = to_amba_driver(dev->driver);
244 const struct amba_id *id = amba_lookup(pcdrv->id_table, pcdev);
248 ret = of_clk_set_defaults(dev->of_node, false);
252 ret = dev_pm_domain_attach(dev, true);
253 if (ret == -EPROBE_DEFER)
256 ret = amba_get_enable_pclk(pcdev);
258 dev_pm_domain_detach(dev, true);
262 pm_runtime_get_noresume(dev);
263 pm_runtime_set_active(dev);
264 pm_runtime_enable(dev);
266 ret = pcdrv->probe(pcdev, id);
270 pm_runtime_disable(dev);
271 pm_runtime_set_suspended(dev);
272 pm_runtime_put_noidle(dev);
274 amba_put_disable_pclk(pcdev);
275 dev_pm_domain_detach(dev, true);
281 static int amba_remove(struct device *dev)
283 struct amba_device *pcdev = to_amba_device(dev);
284 struct amba_driver *drv = to_amba_driver(dev->driver);
287 pm_runtime_get_sync(dev);
288 ret = drv->remove(pcdev);
289 pm_runtime_put_noidle(dev);
291 /* Undo the runtime PM settings in amba_probe() */
292 pm_runtime_disable(dev);
293 pm_runtime_set_suspended(dev);
294 pm_runtime_put_noidle(dev);
296 amba_put_disable_pclk(pcdev);
297 dev_pm_domain_detach(dev, true);
302 static void amba_shutdown(struct device *dev)
304 struct amba_driver *drv = to_amba_driver(dev->driver);
305 drv->shutdown(to_amba_device(dev));
309 * amba_driver_register - register an AMBA device driver
310 * @drv: amba device driver structure
312 * Register an AMBA device driver with the Linux device model
313 * core. If devices pre-exist, the drivers probe function will
316 int amba_driver_register(struct amba_driver *drv)
318 drv->drv.bus = &amba_bustype;
320 #define SETFN(fn) if (drv->fn) drv->drv.fn = amba_##fn
325 return driver_register(&drv->drv);
329 * amba_driver_unregister - remove an AMBA device driver
330 * @drv: AMBA device driver structure to remove
332 * Unregister an AMBA device driver from the Linux device
333 * model. The device model will call the drivers remove function
334 * for each device the device driver is currently handling.
336 void amba_driver_unregister(struct amba_driver *drv)
338 driver_unregister(&drv->drv);
342 static void amba_device_release(struct device *dev)
344 struct amba_device *d = to_amba_device(dev);
347 release_resource(&d->res);
351 static int amba_device_try_add(struct amba_device *dev, struct resource *parent)
357 WARN_ON(dev->irq[0] == (unsigned int)-1);
358 WARN_ON(dev->irq[1] == (unsigned int)-1);
360 ret = request_resource(parent, &dev->res);
364 /* Hard-coded primecell ID instead of plug-n-play */
365 if (dev->periphid != 0)
369 * Dynamically calculate the size of the resource
370 * and use this for iomap
372 size = resource_size(&dev->res);
373 tmp = ioremap(dev->res.start, size);
379 ret = dev_pm_domain_attach(&dev->dev, true);
380 if (ret == -EPROBE_DEFER) {
385 ret = amba_get_enable_pclk(dev);
390 * Read pid and cid based on size of resource
391 * they are located at end of region
393 for (pid = 0, i = 0; i < 4; i++)
394 pid |= (readl(tmp + size - 0x20 + 4 * i) & 255) <<
396 for (cid = 0, i = 0; i < 4; i++)
397 cid |= (readl(tmp + size - 0x10 + 4 * i) & 255) <<
400 amba_put_disable_pclk(dev);
402 if (cid == AMBA_CID || cid == CORESIGHT_CID)
410 dev_pm_domain_detach(&dev->dev, true);
416 ret = device_add(&dev->dev);
421 ret = device_create_file(&dev->dev, &dev_attr_irq0);
422 if (ret == 0 && dev->irq[1])
423 ret = device_create_file(&dev->dev, &dev_attr_irq1);
427 device_unregister(&dev->dev);
430 release_resource(&dev->res);
436 * Registration of AMBA device require reading its pid and cid registers.
437 * To do this, the device must be turned on (if it is a part of power domain)
438 * and have clocks enabled. However in some cases those resources might not be
439 * yet available. Returning EPROBE_DEFER is not a solution in such case,
440 * because callers don't handle this special error code. Instead such devices
441 * are added to the special list and their registration is retried from
442 * periodic worker, until all resources are available and registration succeeds.
444 struct deferred_device {
445 struct amba_device *dev;
446 struct resource *parent;
447 struct list_head node;
450 static LIST_HEAD(deferred_devices);
451 static DEFINE_MUTEX(deferred_devices_lock);
453 static void amba_deferred_retry_func(struct work_struct *dummy);
454 static DECLARE_DELAYED_WORK(deferred_retry_work, amba_deferred_retry_func);
456 #define DEFERRED_DEVICE_TIMEOUT (msecs_to_jiffies(5 * 1000))
458 static void amba_deferred_retry_func(struct work_struct *dummy)
460 struct deferred_device *ddev, *tmp;
462 mutex_lock(&deferred_devices_lock);
464 list_for_each_entry_safe(ddev, tmp, &deferred_devices, node) {
465 int ret = amba_device_try_add(ddev->dev, ddev->parent);
467 if (ret == -EPROBE_DEFER)
470 list_del_init(&ddev->node);
474 if (!list_empty(&deferred_devices))
475 schedule_delayed_work(&deferred_retry_work,
476 DEFERRED_DEVICE_TIMEOUT);
478 mutex_unlock(&deferred_devices_lock);
482 * amba_device_add - add a previously allocated AMBA device structure
483 * @dev: AMBA device allocated by amba_device_alloc
484 * @parent: resource parent for this devices resources
486 * Claim the resource, and read the device cell ID if not already
487 * initialized. Register the AMBA device with the Linux device
490 int amba_device_add(struct amba_device *dev, struct resource *parent)
492 int ret = amba_device_try_add(dev, parent);
494 if (ret == -EPROBE_DEFER) {
495 struct deferred_device *ddev;
497 ddev = kmalloc(sizeof(*ddev), GFP_KERNEL);
502 ddev->parent = parent;
505 mutex_lock(&deferred_devices_lock);
507 if (list_empty(&deferred_devices))
508 schedule_delayed_work(&deferred_retry_work,
509 DEFERRED_DEVICE_TIMEOUT);
510 list_add_tail(&ddev->node, &deferred_devices);
512 mutex_unlock(&deferred_devices_lock);
516 EXPORT_SYMBOL_GPL(amba_device_add);
518 static struct amba_device *
519 amba_aphb_device_add(struct device *parent, const char *name,
520 resource_size_t base, size_t size, int irq1, int irq2,
521 void *pdata, unsigned int periphid, u64 dma_mask,
522 struct resource *resbase)
524 struct amba_device *dev;
527 dev = amba_device_alloc(name, base, size);
529 return ERR_PTR(-ENOMEM);
531 dev->dev.coherent_dma_mask = dma_mask;
534 dev->periphid = periphid;
535 dev->dev.platform_data = pdata;
536 dev->dev.parent = parent;
538 ret = amba_device_add(dev, resbase);
540 amba_device_put(dev);
548 amba_apb_device_add(struct device *parent, const char *name,
549 resource_size_t base, size_t size, int irq1, int irq2,
550 void *pdata, unsigned int periphid)
552 return amba_aphb_device_add(parent, name, base, size, irq1, irq2, pdata,
553 periphid, 0, &iomem_resource);
555 EXPORT_SYMBOL_GPL(amba_apb_device_add);
558 amba_ahb_device_add(struct device *parent, const char *name,
559 resource_size_t base, size_t size, int irq1, int irq2,
560 void *pdata, unsigned int periphid)
562 return amba_aphb_device_add(parent, name, base, size, irq1, irq2, pdata,
563 periphid, ~0ULL, &iomem_resource);
565 EXPORT_SYMBOL_GPL(amba_ahb_device_add);
568 amba_apb_device_add_res(struct device *parent, const char *name,
569 resource_size_t base, size_t size, int irq1,
570 int irq2, void *pdata, unsigned int periphid,
571 struct resource *resbase)
573 return amba_aphb_device_add(parent, name, base, size, irq1, irq2, pdata,
574 periphid, 0, resbase);
576 EXPORT_SYMBOL_GPL(amba_apb_device_add_res);
579 amba_ahb_device_add_res(struct device *parent, const char *name,
580 resource_size_t base, size_t size, int irq1,
581 int irq2, void *pdata, unsigned int periphid,
582 struct resource *resbase)
584 return amba_aphb_device_add(parent, name, base, size, irq1, irq2, pdata,
585 periphid, ~0ULL, resbase);
587 EXPORT_SYMBOL_GPL(amba_ahb_device_add_res);
590 static void amba_device_initialize(struct amba_device *dev, const char *name)
592 device_initialize(&dev->dev);
594 dev_set_name(&dev->dev, "%s", name);
595 dev->dev.release = amba_device_release;
596 dev->dev.bus = &amba_bustype;
597 dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
598 dev->res.name = dev_name(&dev->dev);
602 * amba_device_alloc - allocate an AMBA device
603 * @name: sysfs name of the AMBA device
604 * @base: base of AMBA device
605 * @size: size of AMBA device
607 * Allocate and initialize an AMBA device structure. Returns %NULL
610 struct amba_device *amba_device_alloc(const char *name, resource_size_t base,
613 struct amba_device *dev;
615 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
617 amba_device_initialize(dev, name);
618 dev->res.start = base;
619 dev->res.end = base + size - 1;
620 dev->res.flags = IORESOURCE_MEM;
625 EXPORT_SYMBOL_GPL(amba_device_alloc);
628 * amba_device_register - register an AMBA device
629 * @dev: AMBA device to register
630 * @parent: parent memory resource
632 * Setup the AMBA device, reading the cell ID if present.
633 * Claim the resource, and register the AMBA device with
634 * the Linux device manager.
636 int amba_device_register(struct amba_device *dev, struct resource *parent)
638 amba_device_initialize(dev, dev->dev.init_name);
639 dev->dev.init_name = NULL;
641 return amba_device_add(dev, parent);
645 * amba_device_put - put an AMBA device
646 * @dev: AMBA device to put
648 void amba_device_put(struct amba_device *dev)
650 put_device(&dev->dev);
652 EXPORT_SYMBOL_GPL(amba_device_put);
655 * amba_device_unregister - unregister an AMBA device
656 * @dev: AMBA device to remove
658 * Remove the specified AMBA device from the Linux device
659 * manager. All files associated with this object will be
660 * destroyed, and device drivers notified that the device has
661 * been removed. The AMBA device's resources including
662 * the amba_device structure will be freed once all
663 * references to it have been dropped.
665 void amba_device_unregister(struct amba_device *dev)
667 device_unregister(&dev->dev);
672 struct amba_device *dev;
673 struct device *parent;
679 static int amba_find_match(struct device *dev, void *data)
681 struct find_data *d = data;
682 struct amba_device *pcdev = to_amba_device(dev);
685 r = (pcdev->periphid & d->mask) == d->id;
687 r &= d->parent == dev->parent;
689 r &= strcmp(dev_name(dev), d->busid) == 0;
700 * amba_find_device - locate an AMBA device given a bus id
701 * @busid: bus id for device (or NULL)
702 * @parent: parent device (or NULL)
703 * @id: peripheral ID (or 0)
704 * @mask: peripheral ID mask (or 0)
706 * Return the AMBA device corresponding to the supplied parameters.
707 * If no device matches, returns NULL.
709 * NOTE: When a valid device is found, its refcount is
710 * incremented, and must be decremented before the returned
714 amba_find_device(const char *busid, struct device *parent, unsigned int id,
717 struct find_data data;
720 data.parent = parent;
725 bus_for_each_dev(&amba_bustype, NULL, &data, amba_find_match);
731 * amba_request_regions - request all mem regions associated with device
732 * @dev: amba_device structure for device
733 * @name: name, or NULL to use driver name
735 int amba_request_regions(struct amba_device *dev, const char *name)
741 name = dev->dev.driver->name;
743 size = resource_size(&dev->res);
745 if (!request_mem_region(dev->res.start, size, name))
752 * amba_release_regions - release mem regions associated with device
753 * @dev: amba_device structure for device
755 * Release regions claimed by a successful call to amba_request_regions.
757 void amba_release_regions(struct amba_device *dev)
761 size = resource_size(&dev->res);
762 release_mem_region(dev->res.start, size);
765 EXPORT_SYMBOL(amba_driver_register);
766 EXPORT_SYMBOL(amba_driver_unregister);
767 EXPORT_SYMBOL(amba_device_register);
768 EXPORT_SYMBOL(amba_device_unregister);
769 EXPORT_SYMBOL(amba_find_device);
770 EXPORT_SYMBOL(amba_request_regions);
771 EXPORT_SYMBOL(amba_release_regions);