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>
23 #include <linux/platform_device.h>
27 #define to_amba_driver(d) container_of(d, struct amba_driver, drv)
29 static const struct amba_id *
30 amba_lookup(const struct amba_id *table, struct amba_device *dev)
35 ret = (dev->periphid & table->mask) == table->id;
41 return ret ? table : NULL;
44 static int amba_match(struct device *dev, struct device_driver *drv)
46 struct amba_device *pcdev = to_amba_device(dev);
47 struct amba_driver *pcdrv = to_amba_driver(drv);
49 /* When driver_override is set, only bind to the matching driver */
50 if (pcdev->driver_override)
51 return !strcmp(pcdev->driver_override, drv->name);
53 return amba_lookup(pcdrv->id_table, pcdev) != NULL;
56 static int amba_uevent(struct device *dev, struct kobj_uevent_env *env)
58 struct amba_device *pcdev = to_amba_device(dev);
61 retval = add_uevent_var(env, "AMBA_ID=%08x", pcdev->periphid);
65 retval = add_uevent_var(env, "MODALIAS=amba:d%08X", pcdev->periphid);
69 static ssize_t driver_override_show(struct device *_dev,
70 struct device_attribute *attr, char *buf)
72 struct amba_device *dev = to_amba_device(_dev);
76 len = sprintf(buf, "%s\n", dev->driver_override);
81 static ssize_t driver_override_store(struct device *_dev,
82 struct device_attribute *attr,
83 const char *buf, size_t count)
85 struct amba_device *dev = to_amba_device(_dev);
86 char *driver_override, *old, *cp;
88 /* We need to keep extra room for a newline */
89 if (count >= (PAGE_SIZE - 1))
92 driver_override = kstrndup(buf, count, GFP_KERNEL);
96 cp = strchr(driver_override, '\n');
101 old = dev->driver_override;
102 if (strlen(driver_override)) {
103 dev->driver_override = driver_override;
105 kfree(driver_override);
106 dev->driver_override = NULL;
114 static DEVICE_ATTR_RW(driver_override);
116 #define amba_attr_func(name,fmt,arg...) \
117 static ssize_t name##_show(struct device *_dev, \
118 struct device_attribute *attr, char *buf) \
120 struct amba_device *dev = to_amba_device(_dev); \
121 return sprintf(buf, fmt, arg); \
123 static DEVICE_ATTR_RO(name)
125 amba_attr_func(id, "%08x\n", dev->periphid);
126 amba_attr_func(irq0, "%u\n", dev->irq[0]);
127 amba_attr_func(irq1, "%u\n", dev->irq[1]);
128 amba_attr_func(resource, "\t%016llx\t%016llx\t%016lx\n",
129 (unsigned long long)dev->res.start, (unsigned long long)dev->res.end,
132 static struct attribute *amba_dev_attrs[] = {
134 &dev_attr_resource.attr,
135 &dev_attr_driver_override.attr,
138 ATTRIBUTE_GROUPS(amba_dev);
142 * Hooks to provide runtime PM of the pclk (bus clock). It is safe to
143 * enable/disable the bus clock at runtime PM suspend/resume as this
144 * does not result in loss of context.
146 static int amba_pm_runtime_suspend(struct device *dev)
148 struct amba_device *pcdev = to_amba_device(dev);
149 int ret = pm_generic_runtime_suspend(dev);
151 if (ret == 0 && dev->driver) {
152 if (pm_runtime_is_irq_safe(dev))
153 clk_disable(pcdev->pclk);
155 clk_disable_unprepare(pcdev->pclk);
161 static int amba_pm_runtime_resume(struct device *dev)
163 struct amba_device *pcdev = to_amba_device(dev);
167 if (pm_runtime_is_irq_safe(dev))
168 ret = clk_enable(pcdev->pclk);
170 ret = clk_prepare_enable(pcdev->pclk);
171 /* Failure is probably fatal to the system, but... */
176 return pm_generic_runtime_resume(dev);
178 #endif /* CONFIG_PM */
180 static const struct dev_pm_ops amba_pm = {
181 .suspend = pm_generic_suspend,
182 .resume = pm_generic_resume,
183 .freeze = pm_generic_freeze,
184 .thaw = pm_generic_thaw,
185 .poweroff = pm_generic_poweroff,
186 .restore = pm_generic_restore,
188 amba_pm_runtime_suspend,
189 amba_pm_runtime_resume,
195 * Primecells are part of the Advanced Microcontroller Bus Architecture,
196 * so we call the bus "amba".
197 * DMA configuration for platform and AMBA bus is same. So here we reuse
198 * platform's DMA config routine.
200 struct bus_type amba_bustype = {
202 .dev_groups = amba_dev_groups,
204 .uevent = amba_uevent,
205 .dma_configure = platform_dma_configure,
208 EXPORT_SYMBOL_GPL(amba_bustype);
210 static int __init amba_init(void)
212 return bus_register(&amba_bustype);
215 postcore_initcall(amba_init);
217 static int amba_get_enable_pclk(struct amba_device *pcdev)
221 pcdev->pclk = clk_get(&pcdev->dev, "apb_pclk");
222 if (IS_ERR(pcdev->pclk))
223 return PTR_ERR(pcdev->pclk);
225 ret = clk_prepare_enable(pcdev->pclk);
227 clk_put(pcdev->pclk);
232 static void amba_put_disable_pclk(struct amba_device *pcdev)
234 clk_disable_unprepare(pcdev->pclk);
235 clk_put(pcdev->pclk);
239 * These are the device model conversion veneers; they convert the
240 * device model structures to our more specific structures.
242 static int amba_probe(struct device *dev)
244 struct amba_device *pcdev = to_amba_device(dev);
245 struct amba_driver *pcdrv = to_amba_driver(dev->driver);
246 const struct amba_id *id = amba_lookup(pcdrv->id_table, pcdev);
250 ret = of_clk_set_defaults(dev->of_node, false);
254 ret = dev_pm_domain_attach(dev, true);
258 ret = amba_get_enable_pclk(pcdev);
260 dev_pm_domain_detach(dev, true);
264 pm_runtime_get_noresume(dev);
265 pm_runtime_set_active(dev);
266 pm_runtime_enable(dev);
268 ret = pcdrv->probe(pcdev, id);
272 pm_runtime_disable(dev);
273 pm_runtime_set_suspended(dev);
274 pm_runtime_put_noidle(dev);
276 amba_put_disable_pclk(pcdev);
277 dev_pm_domain_detach(dev, true);
283 static int amba_remove(struct device *dev)
285 struct amba_device *pcdev = to_amba_device(dev);
286 struct amba_driver *drv = to_amba_driver(dev->driver);
289 pm_runtime_get_sync(dev);
291 ret = drv->remove(pcdev);
292 pm_runtime_put_noidle(dev);
294 /* Undo the runtime PM settings in amba_probe() */
295 pm_runtime_disable(dev);
296 pm_runtime_set_suspended(dev);
297 pm_runtime_put_noidle(dev);
299 amba_put_disable_pclk(pcdev);
300 dev_pm_domain_detach(dev, true);
305 static void amba_shutdown(struct device *dev)
307 struct amba_driver *drv = to_amba_driver(dev->driver);
310 drv->shutdown(to_amba_device(dev));
314 * amba_driver_register - register an AMBA device driver
315 * @drv: amba device driver structure
317 * Register an AMBA device driver with the Linux device model
318 * core. If devices pre-exist, the drivers probe function will
321 int amba_driver_register(struct amba_driver *drv)
326 drv->drv.bus = &amba_bustype;
327 drv->drv.probe = amba_probe;
328 drv->drv.remove = amba_remove;
329 drv->drv.shutdown = amba_shutdown;
331 return driver_register(&drv->drv);
335 * amba_driver_unregister - remove an AMBA device driver
336 * @drv: AMBA device driver structure to remove
338 * Unregister an AMBA device driver from the Linux device
339 * model. The device model will call the drivers remove function
340 * for each device the device driver is currently handling.
342 void amba_driver_unregister(struct amba_driver *drv)
344 driver_unregister(&drv->drv);
348 static void amba_device_release(struct device *dev)
350 struct amba_device *d = to_amba_device(dev);
352 of_node_put(d->dev.of_node);
354 release_resource(&d->res);
358 static int amba_device_try_add(struct amba_device *dev, struct resource *parent)
364 ret = request_resource(parent, &dev->res);
368 /* Hard-coded primecell ID instead of plug-n-play */
369 if (dev->periphid != 0)
373 * Dynamically calculate the size of the resource
374 * and use this for iomap
376 size = resource_size(&dev->res);
377 tmp = ioremap(dev->res.start, size);
383 ret = dev_pm_domain_attach(&dev->dev, true);
389 ret = amba_get_enable_pclk(dev);
394 * Read pid and cid based on size of resource
395 * they are located at end of region
397 for (pid = 0, i = 0; i < 4; i++)
398 pid |= (readl(tmp + size - 0x20 + 4 * i) & 255) <<
400 for (cid = 0, i = 0; i < 4; i++)
401 cid |= (readl(tmp + size - 0x10 + 4 * i) & 255) <<
404 amba_put_disable_pclk(dev);
406 if (cid == AMBA_CID || cid == CORESIGHT_CID)
414 dev_pm_domain_detach(&dev->dev, true);
420 ret = device_add(&dev->dev);
425 ret = device_create_file(&dev->dev, &dev_attr_irq0);
426 if (ret == 0 && dev->irq[1])
427 ret = device_create_file(&dev->dev, &dev_attr_irq1);
431 device_unregister(&dev->dev);
434 release_resource(&dev->res);
440 * Registration of AMBA device require reading its pid and cid registers.
441 * To do this, the device must be turned on (if it is a part of power domain)
442 * and have clocks enabled. However in some cases those resources might not be
443 * yet available. Returning EPROBE_DEFER is not a solution in such case,
444 * because callers don't handle this special error code. Instead such devices
445 * are added to the special list and their registration is retried from
446 * periodic worker, until all resources are available and registration succeeds.
448 struct deferred_device {
449 struct amba_device *dev;
450 struct resource *parent;
451 struct list_head node;
454 static LIST_HEAD(deferred_devices);
455 static DEFINE_MUTEX(deferred_devices_lock);
457 static void amba_deferred_retry_func(struct work_struct *dummy);
458 static DECLARE_DELAYED_WORK(deferred_retry_work, amba_deferred_retry_func);
460 #define DEFERRED_DEVICE_TIMEOUT (msecs_to_jiffies(5 * 1000))
462 static void amba_deferred_retry_func(struct work_struct *dummy)
464 struct deferred_device *ddev, *tmp;
466 mutex_lock(&deferred_devices_lock);
468 list_for_each_entry_safe(ddev, tmp, &deferred_devices, node) {
469 int ret = amba_device_try_add(ddev->dev, ddev->parent);
471 if (ret == -EPROBE_DEFER)
474 list_del_init(&ddev->node);
478 if (!list_empty(&deferred_devices))
479 schedule_delayed_work(&deferred_retry_work,
480 DEFERRED_DEVICE_TIMEOUT);
482 mutex_unlock(&deferred_devices_lock);
486 * amba_device_add - add a previously allocated AMBA device structure
487 * @dev: AMBA device allocated by amba_device_alloc
488 * @parent: resource parent for this devices resources
490 * Claim the resource, and read the device cell ID if not already
491 * initialized. Register the AMBA device with the Linux device
494 int amba_device_add(struct amba_device *dev, struct resource *parent)
496 int ret = amba_device_try_add(dev, parent);
498 if (ret == -EPROBE_DEFER) {
499 struct deferred_device *ddev;
501 ddev = kmalloc(sizeof(*ddev), GFP_KERNEL);
506 ddev->parent = parent;
509 mutex_lock(&deferred_devices_lock);
511 if (list_empty(&deferred_devices))
512 schedule_delayed_work(&deferred_retry_work,
513 DEFERRED_DEVICE_TIMEOUT);
514 list_add_tail(&ddev->node, &deferred_devices);
516 mutex_unlock(&deferred_devices_lock);
520 EXPORT_SYMBOL_GPL(amba_device_add);
522 static struct amba_device *
523 amba_aphb_device_add(struct device *parent, const char *name,
524 resource_size_t base, size_t size, int irq1, int irq2,
525 void *pdata, unsigned int periphid, u64 dma_mask,
526 struct resource *resbase)
528 struct amba_device *dev;
531 dev = amba_device_alloc(name, base, size);
533 return ERR_PTR(-ENOMEM);
535 dev->dev.coherent_dma_mask = dma_mask;
538 dev->periphid = periphid;
539 dev->dev.platform_data = pdata;
540 dev->dev.parent = parent;
542 ret = amba_device_add(dev, resbase);
544 amba_device_put(dev);
552 amba_apb_device_add(struct device *parent, const char *name,
553 resource_size_t base, size_t size, int irq1, int irq2,
554 void *pdata, unsigned int periphid)
556 return amba_aphb_device_add(parent, name, base, size, irq1, irq2, pdata,
557 periphid, 0, &iomem_resource);
559 EXPORT_SYMBOL_GPL(amba_apb_device_add);
562 amba_ahb_device_add(struct device *parent, const char *name,
563 resource_size_t base, size_t size, int irq1, int irq2,
564 void *pdata, unsigned int periphid)
566 return amba_aphb_device_add(parent, name, base, size, irq1, irq2, pdata,
567 periphid, ~0ULL, &iomem_resource);
569 EXPORT_SYMBOL_GPL(amba_ahb_device_add);
572 amba_apb_device_add_res(struct device *parent, const char *name,
573 resource_size_t base, size_t size, int irq1,
574 int irq2, void *pdata, unsigned int periphid,
575 struct resource *resbase)
577 return amba_aphb_device_add(parent, name, base, size, irq1, irq2, pdata,
578 periphid, 0, resbase);
580 EXPORT_SYMBOL_GPL(amba_apb_device_add_res);
583 amba_ahb_device_add_res(struct device *parent, const char *name,
584 resource_size_t base, size_t size, int irq1,
585 int irq2, void *pdata, unsigned int periphid,
586 struct resource *resbase)
588 return amba_aphb_device_add(parent, name, base, size, irq1, irq2, pdata,
589 periphid, ~0ULL, resbase);
591 EXPORT_SYMBOL_GPL(amba_ahb_device_add_res);
594 static void amba_device_initialize(struct amba_device *dev, const char *name)
596 device_initialize(&dev->dev);
598 dev_set_name(&dev->dev, "%s", name);
599 dev->dev.release = amba_device_release;
600 dev->dev.bus = &amba_bustype;
601 dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
602 dev->res.name = dev_name(&dev->dev);
606 * amba_device_alloc - allocate an AMBA device
607 * @name: sysfs name of the AMBA device
608 * @base: base of AMBA device
609 * @size: size of AMBA device
611 * Allocate and initialize an AMBA device structure. Returns %NULL
614 struct amba_device *amba_device_alloc(const char *name, resource_size_t base,
617 struct amba_device *dev;
619 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
621 amba_device_initialize(dev, name);
622 dev->res.start = base;
623 dev->res.end = base + size - 1;
624 dev->res.flags = IORESOURCE_MEM;
629 EXPORT_SYMBOL_GPL(amba_device_alloc);
632 * amba_device_register - register an AMBA device
633 * @dev: AMBA device to register
634 * @parent: parent memory resource
636 * Setup the AMBA device, reading the cell ID if present.
637 * Claim the resource, and register the AMBA device with
638 * the Linux device manager.
640 int amba_device_register(struct amba_device *dev, struct resource *parent)
642 amba_device_initialize(dev, dev->dev.init_name);
643 dev->dev.init_name = NULL;
645 return amba_device_add(dev, parent);
649 * amba_device_put - put an AMBA device
650 * @dev: AMBA device to put
652 void amba_device_put(struct amba_device *dev)
654 put_device(&dev->dev);
656 EXPORT_SYMBOL_GPL(amba_device_put);
659 * amba_device_unregister - unregister an AMBA device
660 * @dev: AMBA device to remove
662 * Remove the specified AMBA device from the Linux device
663 * manager. All files associated with this object will be
664 * destroyed, and device drivers notified that the device has
665 * been removed. The AMBA device's resources including
666 * the amba_device structure will be freed once all
667 * references to it have been dropped.
669 void amba_device_unregister(struct amba_device *dev)
671 device_unregister(&dev->dev);
676 struct amba_device *dev;
677 struct device *parent;
683 static int amba_find_match(struct device *dev, void *data)
685 struct find_data *d = data;
686 struct amba_device *pcdev = to_amba_device(dev);
689 r = (pcdev->periphid & d->mask) == d->id;
691 r &= d->parent == dev->parent;
693 r &= strcmp(dev_name(dev), d->busid) == 0;
704 * amba_find_device - locate an AMBA device given a bus id
705 * @busid: bus id for device (or NULL)
706 * @parent: parent device (or NULL)
707 * @id: peripheral ID (or 0)
708 * @mask: peripheral ID mask (or 0)
710 * Return the AMBA device corresponding to the supplied parameters.
711 * If no device matches, returns NULL.
713 * NOTE: When a valid device is found, its refcount is
714 * incremented, and must be decremented before the returned
718 amba_find_device(const char *busid, struct device *parent, unsigned int id,
721 struct find_data data;
724 data.parent = parent;
729 bus_for_each_dev(&amba_bustype, NULL, &data, amba_find_match);
735 * amba_request_regions - request all mem regions associated with device
736 * @dev: amba_device structure for device
737 * @name: name, or NULL to use driver name
739 int amba_request_regions(struct amba_device *dev, const char *name)
745 name = dev->dev.driver->name;
747 size = resource_size(&dev->res);
749 if (!request_mem_region(dev->res.start, size, name))
756 * amba_release_regions - release mem regions associated with device
757 * @dev: amba_device structure for device
759 * Release regions claimed by a successful call to amba_request_regions.
761 void amba_release_regions(struct amba_device *dev)
765 size = resource_size(&dev->res);
766 release_mem_region(dev->res.start, size);
769 EXPORT_SYMBOL(amba_driver_register);
770 EXPORT_SYMBOL(amba_driver_unregister);
771 EXPORT_SYMBOL(amba_device_register);
772 EXPORT_SYMBOL(amba_device_unregister);
773 EXPORT_SYMBOL(amba_find_device);
774 EXPORT_SYMBOL(amba_request_regions);
775 EXPORT_SYMBOL(amba_release_regions);