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);
73 if (!dev->driver_override)
76 return sprintf(buf, "%s\n", dev->driver_override);
79 static ssize_t driver_override_store(struct device *_dev,
80 struct device_attribute *attr,
81 const char *buf, size_t count)
83 struct amba_device *dev = to_amba_device(_dev);
84 char *driver_override, *old = dev->driver_override, *cp;
89 driver_override = kstrndup(buf, count, GFP_KERNEL);
93 cp = strchr(driver_override, '\n');
97 if (strlen(driver_override)) {
98 dev->driver_override = driver_override;
100 kfree(driver_override);
101 dev->driver_override = NULL;
108 static DEVICE_ATTR_RW(driver_override);
110 #define amba_attr_func(name,fmt,arg...) \
111 static ssize_t name##_show(struct device *_dev, \
112 struct device_attribute *attr, char *buf) \
114 struct amba_device *dev = to_amba_device(_dev); \
115 return sprintf(buf, fmt, arg); \
117 static DEVICE_ATTR_RO(name)
119 amba_attr_func(id, "%08x\n", dev->periphid);
120 amba_attr_func(irq0, "%u\n", dev->irq[0]);
121 amba_attr_func(irq1, "%u\n", dev->irq[1]);
122 amba_attr_func(resource, "\t%016llx\t%016llx\t%016lx\n",
123 (unsigned long long)dev->res.start, (unsigned long long)dev->res.end,
126 static struct attribute *amba_dev_attrs[] = {
128 &dev_attr_resource.attr,
129 &dev_attr_driver_override.attr,
132 ATTRIBUTE_GROUPS(amba_dev);
136 * Hooks to provide runtime PM of the pclk (bus clock). It is safe to
137 * enable/disable the bus clock at runtime PM suspend/resume as this
138 * does not result in loss of context.
140 static int amba_pm_runtime_suspend(struct device *dev)
142 struct amba_device *pcdev = to_amba_device(dev);
143 int ret = pm_generic_runtime_suspend(dev);
145 if (ret == 0 && dev->driver) {
146 if (pm_runtime_is_irq_safe(dev))
147 clk_disable(pcdev->pclk);
149 clk_disable_unprepare(pcdev->pclk);
155 static int amba_pm_runtime_resume(struct device *dev)
157 struct amba_device *pcdev = to_amba_device(dev);
161 if (pm_runtime_is_irq_safe(dev))
162 ret = clk_enable(pcdev->pclk);
164 ret = clk_prepare_enable(pcdev->pclk);
165 /* Failure is probably fatal to the system, but... */
170 return pm_generic_runtime_resume(dev);
172 #endif /* CONFIG_PM */
174 static const struct dev_pm_ops amba_pm = {
175 .suspend = pm_generic_suspend,
176 .resume = pm_generic_resume,
177 .freeze = pm_generic_freeze,
178 .thaw = pm_generic_thaw,
179 .poweroff = pm_generic_poweroff,
180 .restore = pm_generic_restore,
182 amba_pm_runtime_suspend,
183 amba_pm_runtime_resume,
189 * Primecells are part of the Advanced Microcontroller Bus Architecture,
190 * so we call the bus "amba".
192 struct bus_type amba_bustype = {
194 .dev_groups = amba_dev_groups,
196 .uevent = amba_uevent,
200 static int __init amba_init(void)
202 return bus_register(&amba_bustype);
205 postcore_initcall(amba_init);
207 static int amba_get_enable_pclk(struct amba_device *pcdev)
211 pcdev->pclk = clk_get(&pcdev->dev, "apb_pclk");
212 if (IS_ERR(pcdev->pclk))
213 return PTR_ERR(pcdev->pclk);
215 ret = clk_prepare_enable(pcdev->pclk);
217 clk_put(pcdev->pclk);
222 static void amba_put_disable_pclk(struct amba_device *pcdev)
224 clk_disable_unprepare(pcdev->pclk);
225 clk_put(pcdev->pclk);
229 * These are the device model conversion veneers; they convert the
230 * device model structures to our more specific structures.
232 static int amba_probe(struct device *dev)
234 struct amba_device *pcdev = to_amba_device(dev);
235 struct amba_driver *pcdrv = to_amba_driver(dev->driver);
236 const struct amba_id *id = amba_lookup(pcdrv->id_table, pcdev);
240 ret = of_clk_set_defaults(dev->of_node, false);
244 ret = dev_pm_domain_attach(dev, true);
245 if (ret == -EPROBE_DEFER)
248 ret = amba_get_enable_pclk(pcdev);
250 dev_pm_domain_detach(dev, true);
254 pm_runtime_get_noresume(dev);
255 pm_runtime_set_active(dev);
256 pm_runtime_enable(dev);
258 ret = pcdrv->probe(pcdev, id);
262 pm_runtime_disable(dev);
263 pm_runtime_set_suspended(dev);
264 pm_runtime_put_noidle(dev);
266 amba_put_disable_pclk(pcdev);
267 dev_pm_domain_detach(dev, true);
273 static int amba_remove(struct device *dev)
275 struct amba_device *pcdev = to_amba_device(dev);
276 struct amba_driver *drv = to_amba_driver(dev->driver);
279 pm_runtime_get_sync(dev);
280 ret = drv->remove(pcdev);
281 pm_runtime_put_noidle(dev);
283 /* Undo the runtime PM settings in amba_probe() */
284 pm_runtime_disable(dev);
285 pm_runtime_set_suspended(dev);
286 pm_runtime_put_noidle(dev);
288 amba_put_disable_pclk(pcdev);
289 dev_pm_domain_detach(dev, true);
294 static void amba_shutdown(struct device *dev)
296 struct amba_driver *drv = to_amba_driver(dev->driver);
297 drv->shutdown(to_amba_device(dev));
301 * amba_driver_register - register an AMBA device driver
302 * @drv: amba device driver structure
304 * Register an AMBA device driver with the Linux device model
305 * core. If devices pre-exist, the drivers probe function will
308 int amba_driver_register(struct amba_driver *drv)
310 drv->drv.bus = &amba_bustype;
312 #define SETFN(fn) if (drv->fn) drv->drv.fn = amba_##fn
317 return driver_register(&drv->drv);
321 * amba_driver_unregister - remove an AMBA device driver
322 * @drv: AMBA device driver structure to remove
324 * Unregister an AMBA device driver from the Linux device
325 * model. The device model will call the drivers remove function
326 * for each device the device driver is currently handling.
328 void amba_driver_unregister(struct amba_driver *drv)
330 driver_unregister(&drv->drv);
334 static void amba_device_release(struct device *dev)
336 struct amba_device *d = to_amba_device(dev);
339 release_resource(&d->res);
343 static int amba_device_try_add(struct amba_device *dev, struct resource *parent)
349 WARN_ON(dev->irq[0] == (unsigned int)-1);
350 WARN_ON(dev->irq[1] == (unsigned int)-1);
352 ret = request_resource(parent, &dev->res);
356 /* Hard-coded primecell ID instead of plug-n-play */
357 if (dev->periphid != 0)
361 * Dynamically calculate the size of the resource
362 * and use this for iomap
364 size = resource_size(&dev->res);
365 tmp = ioremap(dev->res.start, size);
371 ret = dev_pm_domain_attach(&dev->dev, true);
372 if (ret == -EPROBE_DEFER) {
377 ret = amba_get_enable_pclk(dev);
382 * Read pid and cid based on size of resource
383 * they are located at end of region
385 for (pid = 0, i = 0; i < 4; i++)
386 pid |= (readl(tmp + size - 0x20 + 4 * i) & 255) <<
388 for (cid = 0, i = 0; i < 4; i++)
389 cid |= (readl(tmp + size - 0x10 + 4 * i) & 255) <<
392 amba_put_disable_pclk(dev);
394 if (cid == AMBA_CID || cid == CORESIGHT_CID)
402 dev_pm_domain_detach(&dev->dev, true);
408 ret = device_add(&dev->dev);
413 ret = device_create_file(&dev->dev, &dev_attr_irq0);
414 if (ret == 0 && dev->irq[1])
415 ret = device_create_file(&dev->dev, &dev_attr_irq1);
419 device_unregister(&dev->dev);
422 release_resource(&dev->res);
428 * Registration of AMBA device require reading its pid and cid registers.
429 * To do this, the device must be turned on (if it is a part of power domain)
430 * and have clocks enabled. However in some cases those resources might not be
431 * yet available. Returning EPROBE_DEFER is not a solution in such case,
432 * because callers don't handle this special error code. Instead such devices
433 * are added to the special list and their registration is retried from
434 * periodic worker, until all resources are available and registration succeeds.
436 struct deferred_device {
437 struct amba_device *dev;
438 struct resource *parent;
439 struct list_head node;
442 static LIST_HEAD(deferred_devices);
443 static DEFINE_MUTEX(deferred_devices_lock);
445 static void amba_deferred_retry_func(struct work_struct *dummy);
446 static DECLARE_DELAYED_WORK(deferred_retry_work, amba_deferred_retry_func);
448 #define DEFERRED_DEVICE_TIMEOUT (msecs_to_jiffies(5 * 1000))
450 static void amba_deferred_retry_func(struct work_struct *dummy)
452 struct deferred_device *ddev, *tmp;
454 mutex_lock(&deferred_devices_lock);
456 list_for_each_entry_safe(ddev, tmp, &deferred_devices, node) {
457 int ret = amba_device_try_add(ddev->dev, ddev->parent);
459 if (ret == -EPROBE_DEFER)
462 list_del_init(&ddev->node);
466 if (!list_empty(&deferred_devices))
467 schedule_delayed_work(&deferred_retry_work,
468 DEFERRED_DEVICE_TIMEOUT);
470 mutex_unlock(&deferred_devices_lock);
474 * amba_device_add - add a previously allocated AMBA device structure
475 * @dev: AMBA device allocated by amba_device_alloc
476 * @parent: resource parent for this devices resources
478 * Claim the resource, and read the device cell ID if not already
479 * initialized. Register the AMBA device with the Linux device
482 int amba_device_add(struct amba_device *dev, struct resource *parent)
484 int ret = amba_device_try_add(dev, parent);
486 if (ret == -EPROBE_DEFER) {
487 struct deferred_device *ddev;
489 ddev = kmalloc(sizeof(*ddev), GFP_KERNEL);
494 ddev->parent = parent;
497 mutex_lock(&deferred_devices_lock);
499 if (list_empty(&deferred_devices))
500 schedule_delayed_work(&deferred_retry_work,
501 DEFERRED_DEVICE_TIMEOUT);
502 list_add_tail(&ddev->node, &deferred_devices);
504 mutex_unlock(&deferred_devices_lock);
508 EXPORT_SYMBOL_GPL(amba_device_add);
510 static struct amba_device *
511 amba_aphb_device_add(struct device *parent, const char *name,
512 resource_size_t base, size_t size, int irq1, int irq2,
513 void *pdata, unsigned int periphid, u64 dma_mask,
514 struct resource *resbase)
516 struct amba_device *dev;
519 dev = amba_device_alloc(name, base, size);
521 return ERR_PTR(-ENOMEM);
523 dev->dev.coherent_dma_mask = dma_mask;
526 dev->periphid = periphid;
527 dev->dev.platform_data = pdata;
528 dev->dev.parent = parent;
530 ret = amba_device_add(dev, resbase);
532 amba_device_put(dev);
540 amba_apb_device_add(struct device *parent, const char *name,
541 resource_size_t base, size_t size, int irq1, int irq2,
542 void *pdata, unsigned int periphid)
544 return amba_aphb_device_add(parent, name, base, size, irq1, irq2, pdata,
545 periphid, 0, &iomem_resource);
547 EXPORT_SYMBOL_GPL(amba_apb_device_add);
550 amba_ahb_device_add(struct device *parent, const char *name,
551 resource_size_t base, size_t size, int irq1, int irq2,
552 void *pdata, unsigned int periphid)
554 return amba_aphb_device_add(parent, name, base, size, irq1, irq2, pdata,
555 periphid, ~0ULL, &iomem_resource);
557 EXPORT_SYMBOL_GPL(amba_ahb_device_add);
560 amba_apb_device_add_res(struct device *parent, const char *name,
561 resource_size_t base, size_t size, int irq1,
562 int irq2, void *pdata, unsigned int periphid,
563 struct resource *resbase)
565 return amba_aphb_device_add(parent, name, base, size, irq1, irq2, pdata,
566 periphid, 0, resbase);
568 EXPORT_SYMBOL_GPL(amba_apb_device_add_res);
571 amba_ahb_device_add_res(struct device *parent, const char *name,
572 resource_size_t base, size_t size, int irq1,
573 int irq2, void *pdata, unsigned int periphid,
574 struct resource *resbase)
576 return amba_aphb_device_add(parent, name, base, size, irq1, irq2, pdata,
577 periphid, ~0ULL, resbase);
579 EXPORT_SYMBOL_GPL(amba_ahb_device_add_res);
582 static void amba_device_initialize(struct amba_device *dev, const char *name)
584 device_initialize(&dev->dev);
586 dev_set_name(&dev->dev, "%s", name);
587 dev->dev.release = amba_device_release;
588 dev->dev.bus = &amba_bustype;
589 dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
590 dev->res.name = dev_name(&dev->dev);
594 * amba_device_alloc - allocate an AMBA device
595 * @name: sysfs name of the AMBA device
596 * @base: base of AMBA device
597 * @size: size of AMBA device
599 * Allocate and initialize an AMBA device structure. Returns %NULL
602 struct amba_device *amba_device_alloc(const char *name, resource_size_t base,
605 struct amba_device *dev;
607 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
609 amba_device_initialize(dev, name);
610 dev->res.start = base;
611 dev->res.end = base + size - 1;
612 dev->res.flags = IORESOURCE_MEM;
617 EXPORT_SYMBOL_GPL(amba_device_alloc);
620 * amba_device_register - register an AMBA device
621 * @dev: AMBA device to register
622 * @parent: parent memory resource
624 * Setup the AMBA device, reading the cell ID if present.
625 * Claim the resource, and register the AMBA device with
626 * the Linux device manager.
628 int amba_device_register(struct amba_device *dev, struct resource *parent)
630 amba_device_initialize(dev, dev->dev.init_name);
631 dev->dev.init_name = NULL;
633 return amba_device_add(dev, parent);
637 * amba_device_put - put an AMBA device
638 * @dev: AMBA device to put
640 void amba_device_put(struct amba_device *dev)
642 put_device(&dev->dev);
644 EXPORT_SYMBOL_GPL(amba_device_put);
647 * amba_device_unregister - unregister an AMBA device
648 * @dev: AMBA device to remove
650 * Remove the specified AMBA device from the Linux device
651 * manager. All files associated with this object will be
652 * destroyed, and device drivers notified that the device has
653 * been removed. The AMBA device's resources including
654 * the amba_device structure will be freed once all
655 * references to it have been dropped.
657 void amba_device_unregister(struct amba_device *dev)
659 device_unregister(&dev->dev);
664 struct amba_device *dev;
665 struct device *parent;
671 static int amba_find_match(struct device *dev, void *data)
673 struct find_data *d = data;
674 struct amba_device *pcdev = to_amba_device(dev);
677 r = (pcdev->periphid & d->mask) == d->id;
679 r &= d->parent == dev->parent;
681 r &= strcmp(dev_name(dev), d->busid) == 0;
692 * amba_find_device - locate an AMBA device given a bus id
693 * @busid: bus id for device (or NULL)
694 * @parent: parent device (or NULL)
695 * @id: peripheral ID (or 0)
696 * @mask: peripheral ID mask (or 0)
698 * Return the AMBA device corresponding to the supplied parameters.
699 * If no device matches, returns NULL.
701 * NOTE: When a valid device is found, its refcount is
702 * incremented, and must be decremented before the returned
706 amba_find_device(const char *busid, struct device *parent, unsigned int id,
709 struct find_data data;
712 data.parent = parent;
717 bus_for_each_dev(&amba_bustype, NULL, &data, amba_find_match);
723 * amba_request_regions - request all mem regions associated with device
724 * @dev: amba_device structure for device
725 * @name: name, or NULL to use driver name
727 int amba_request_regions(struct amba_device *dev, const char *name)
733 name = dev->dev.driver->name;
735 size = resource_size(&dev->res);
737 if (!request_mem_region(dev->res.start, size, name))
744 * amba_release_regions - release mem regions associated with device
745 * @dev: amba_device structure for device
747 * Release regions claimed by a successful call to amba_request_regions.
749 void amba_release_regions(struct amba_device *dev)
753 size = resource_size(&dev->res);
754 release_mem_region(dev->res.start, size);
757 EXPORT_SYMBOL(amba_driver_register);
758 EXPORT_SYMBOL(amba_driver_unregister);
759 EXPORT_SYMBOL(amba_device_register);
760 EXPORT_SYMBOL(amba_device_unregister);
761 EXPORT_SYMBOL(amba_find_device);
762 EXPORT_SYMBOL(amba_request_regions);
763 EXPORT_SYMBOL(amba_release_regions);