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);
75 len = sprintf(buf, "%s\n", dev->driver_override);
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))
91 driver_override = kstrndup(buf, count, GFP_KERNEL);
95 cp = strchr(driver_override, '\n');
100 old = dev->driver_override;
101 if (strlen(driver_override)) {
102 dev->driver_override = driver_override;
104 kfree(driver_override);
105 dev->driver_override = NULL;
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,
131 static struct attribute *amba_dev_attrs[] = {
133 &dev_attr_resource.attr,
134 &dev_attr_driver_override.attr,
137 ATTRIBUTE_GROUPS(amba_dev);
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);
154 clk_disable_unprepare(pcdev->pclk);
160 static int amba_pm_runtime_resume(struct device *dev)
162 struct amba_device *pcdev = to_amba_device(dev);
166 if (pm_runtime_is_irq_safe(dev))
167 ret = clk_enable(pcdev->pclk);
169 ret = clk_prepare_enable(pcdev->pclk);
170 /* Failure is probably fatal to the system, but... */
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,
187 amba_pm_runtime_suspend,
188 amba_pm_runtime_resume,
194 * Primecells are part of the Advanced Microcontroller Bus Architecture,
195 * so we call the bus "amba".
197 struct bus_type amba_bustype = {
199 .dev_groups = amba_dev_groups,
201 .uevent = amba_uevent,
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)
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);
222 clk_put(pcdev->pclk);
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);
245 ret = of_clk_set_defaults(dev->of_node, false);
249 ret = dev_pm_domain_attach(dev, true);
250 if (ret == -EPROBE_DEFER)
253 ret = amba_get_enable_pclk(pcdev);
255 dev_pm_domain_detach(dev, true);
259 pm_runtime_get_noresume(dev);
260 pm_runtime_set_active(dev);
261 pm_runtime_enable(dev);
263 ret = pcdrv->probe(pcdev, id);
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);
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);
284 pm_runtime_get_sync(dev);
286 ret = drv->remove(pcdev);
287 pm_runtime_put_noidle(dev);
289 /* Undo the runtime PM settings in amba_probe() */
290 pm_runtime_disable(dev);
291 pm_runtime_set_suspended(dev);
292 pm_runtime_put_noidle(dev);
294 amba_put_disable_pclk(pcdev);
295 dev_pm_domain_detach(dev, true);
300 static void amba_shutdown(struct device *dev)
302 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)
321 drv->drv.bus = &amba_bustype;
322 drv->drv.probe = amba_probe;
323 drv->drv.remove = amba_remove;
324 drv->drv.shutdown = amba_shutdown;
326 return driver_register(&drv->drv);
330 * amba_driver_unregister - remove an AMBA device driver
331 * @drv: AMBA device driver structure to remove
333 * Unregister an AMBA device driver from the Linux device
334 * model. The device model will call the drivers remove function
335 * for each device the device driver is currently handling.
337 void amba_driver_unregister(struct amba_driver *drv)
339 driver_unregister(&drv->drv);
343 static void amba_device_release(struct device *dev)
345 struct amba_device *d = to_amba_device(dev);
348 release_resource(&d->res);
352 static int amba_device_try_add(struct amba_device *dev, struct resource *parent)
358 ret = request_resource(parent, &dev->res);
362 /* Hard-coded primecell ID instead of plug-n-play */
363 if (dev->periphid != 0)
367 * Dynamically calculate the size of the resource
368 * and use this for iomap
370 size = resource_size(&dev->res);
371 tmp = ioremap(dev->res.start, size);
377 ret = dev_pm_domain_attach(&dev->dev, true);
378 if (ret == -EPROBE_DEFER) {
383 ret = amba_get_enable_pclk(dev);
388 * Read pid and cid based on size of resource
389 * they are located at end of region
391 for (pid = 0, i = 0; i < 4; i++)
392 pid |= (readl(tmp + size - 0x20 + 4 * i) & 255) <<
394 for (cid = 0, i = 0; i < 4; i++)
395 cid |= (readl(tmp + size - 0x10 + 4 * i) & 255) <<
398 amba_put_disable_pclk(dev);
400 if (cid == AMBA_CID || cid == CORESIGHT_CID)
408 dev_pm_domain_detach(&dev->dev, true);
414 ret = device_add(&dev->dev);
419 ret = device_create_file(&dev->dev, &dev_attr_irq0);
420 if (ret == 0 && dev->irq[1])
421 ret = device_create_file(&dev->dev, &dev_attr_irq1);
425 device_unregister(&dev->dev);
428 release_resource(&dev->res);
434 * Registration of AMBA device require reading its pid and cid registers.
435 * To do this, the device must be turned on (if it is a part of power domain)
436 * and have clocks enabled. However in some cases those resources might not be
437 * yet available. Returning EPROBE_DEFER is not a solution in such case,
438 * because callers don't handle this special error code. Instead such devices
439 * are added to the special list and their registration is retried from
440 * periodic worker, until all resources are available and registration succeeds.
442 struct deferred_device {
443 struct amba_device *dev;
444 struct resource *parent;
445 struct list_head node;
448 static LIST_HEAD(deferred_devices);
449 static DEFINE_MUTEX(deferred_devices_lock);
451 static void amba_deferred_retry_func(struct work_struct *dummy);
452 static DECLARE_DELAYED_WORK(deferred_retry_work, amba_deferred_retry_func);
454 #define DEFERRED_DEVICE_TIMEOUT (msecs_to_jiffies(5 * 1000))
456 static void amba_deferred_retry_func(struct work_struct *dummy)
458 struct deferred_device *ddev, *tmp;
460 mutex_lock(&deferred_devices_lock);
462 list_for_each_entry_safe(ddev, tmp, &deferred_devices, node) {
463 int ret = amba_device_try_add(ddev->dev, ddev->parent);
465 if (ret == -EPROBE_DEFER)
468 list_del_init(&ddev->node);
472 if (!list_empty(&deferred_devices))
473 schedule_delayed_work(&deferred_retry_work,
474 DEFERRED_DEVICE_TIMEOUT);
476 mutex_unlock(&deferred_devices_lock);
480 * amba_device_add - add a previously allocated AMBA device structure
481 * @dev: AMBA device allocated by amba_device_alloc
482 * @parent: resource parent for this devices resources
484 * Claim the resource, and read the device cell ID if not already
485 * initialized. Register the AMBA device with the Linux device
488 int amba_device_add(struct amba_device *dev, struct resource *parent)
490 int ret = amba_device_try_add(dev, parent);
492 if (ret == -EPROBE_DEFER) {
493 struct deferred_device *ddev;
495 ddev = kmalloc(sizeof(*ddev), GFP_KERNEL);
500 ddev->parent = parent;
503 mutex_lock(&deferred_devices_lock);
505 if (list_empty(&deferred_devices))
506 schedule_delayed_work(&deferred_retry_work,
507 DEFERRED_DEVICE_TIMEOUT);
508 list_add_tail(&ddev->node, &deferred_devices);
510 mutex_unlock(&deferred_devices_lock);
514 EXPORT_SYMBOL_GPL(amba_device_add);
516 static struct amba_device *
517 amba_aphb_device_add(struct device *parent, const char *name,
518 resource_size_t base, size_t size, int irq1, int irq2,
519 void *pdata, unsigned int periphid, u64 dma_mask,
520 struct resource *resbase)
522 struct amba_device *dev;
525 dev = amba_device_alloc(name, base, size);
527 return ERR_PTR(-ENOMEM);
529 dev->dev.coherent_dma_mask = dma_mask;
532 dev->periphid = periphid;
533 dev->dev.platform_data = pdata;
534 dev->dev.parent = parent;
536 ret = amba_device_add(dev, resbase);
538 amba_device_put(dev);
546 amba_apb_device_add(struct device *parent, const char *name,
547 resource_size_t base, size_t size, int irq1, int irq2,
548 void *pdata, unsigned int periphid)
550 return amba_aphb_device_add(parent, name, base, size, irq1, irq2, pdata,
551 periphid, 0, &iomem_resource);
553 EXPORT_SYMBOL_GPL(amba_apb_device_add);
556 amba_ahb_device_add(struct device *parent, const char *name,
557 resource_size_t base, size_t size, int irq1, int irq2,
558 void *pdata, unsigned int periphid)
560 return amba_aphb_device_add(parent, name, base, size, irq1, irq2, pdata,
561 periphid, ~0ULL, &iomem_resource);
563 EXPORT_SYMBOL_GPL(amba_ahb_device_add);
566 amba_apb_device_add_res(struct device *parent, const char *name,
567 resource_size_t base, size_t size, int irq1,
568 int irq2, void *pdata, unsigned int periphid,
569 struct resource *resbase)
571 return amba_aphb_device_add(parent, name, base, size, irq1, irq2, pdata,
572 periphid, 0, resbase);
574 EXPORT_SYMBOL_GPL(amba_apb_device_add_res);
577 amba_ahb_device_add_res(struct device *parent, const char *name,
578 resource_size_t base, size_t size, int irq1,
579 int irq2, void *pdata, unsigned int periphid,
580 struct resource *resbase)
582 return amba_aphb_device_add(parent, name, base, size, irq1, irq2, pdata,
583 periphid, ~0ULL, resbase);
585 EXPORT_SYMBOL_GPL(amba_ahb_device_add_res);
588 static void amba_device_initialize(struct amba_device *dev, const char *name)
590 device_initialize(&dev->dev);
592 dev_set_name(&dev->dev, "%s", name);
593 dev->dev.release = amba_device_release;
594 dev->dev.bus = &amba_bustype;
595 dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
596 dev->res.name = dev_name(&dev->dev);
600 * amba_device_alloc - allocate an AMBA device
601 * @name: sysfs name of the AMBA device
602 * @base: base of AMBA device
603 * @size: size of AMBA device
605 * Allocate and initialize an AMBA device structure. Returns %NULL
608 struct amba_device *amba_device_alloc(const char *name, resource_size_t base,
611 struct amba_device *dev;
613 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
615 amba_device_initialize(dev, name);
616 dev->res.start = base;
617 dev->res.end = base + size - 1;
618 dev->res.flags = IORESOURCE_MEM;
623 EXPORT_SYMBOL_GPL(amba_device_alloc);
626 * amba_device_register - register an AMBA device
627 * @dev: AMBA device to register
628 * @parent: parent memory resource
630 * Setup the AMBA device, reading the cell ID if present.
631 * Claim the resource, and register the AMBA device with
632 * the Linux device manager.
634 int amba_device_register(struct amba_device *dev, struct resource *parent)
636 amba_device_initialize(dev, dev->dev.init_name);
637 dev->dev.init_name = NULL;
639 return amba_device_add(dev, parent);
643 * amba_device_put - put an AMBA device
644 * @dev: AMBA device to put
646 void amba_device_put(struct amba_device *dev)
648 put_device(&dev->dev);
650 EXPORT_SYMBOL_GPL(amba_device_put);
653 * amba_device_unregister - unregister an AMBA device
654 * @dev: AMBA device to remove
656 * Remove the specified AMBA device from the Linux device
657 * manager. All files associated with this object will be
658 * destroyed, and device drivers notified that the device has
659 * been removed. The AMBA device's resources including
660 * the amba_device structure will be freed once all
661 * references to it have been dropped.
663 void amba_device_unregister(struct amba_device *dev)
665 device_unregister(&dev->dev);
670 struct amba_device *dev;
671 struct device *parent;
677 static int amba_find_match(struct device *dev, void *data)
679 struct find_data *d = data;
680 struct amba_device *pcdev = to_amba_device(dev);
683 r = (pcdev->periphid & d->mask) == d->id;
685 r &= d->parent == dev->parent;
687 r &= strcmp(dev_name(dev), d->busid) == 0;
698 * amba_find_device - locate an AMBA device given a bus id
699 * @busid: bus id for device (or NULL)
700 * @parent: parent device (or NULL)
701 * @id: peripheral ID (or 0)
702 * @mask: peripheral ID mask (or 0)
704 * Return the AMBA device corresponding to the supplied parameters.
705 * If no device matches, returns NULL.
707 * NOTE: When a valid device is found, its refcount is
708 * incremented, and must be decremented before the returned
712 amba_find_device(const char *busid, struct device *parent, unsigned int id,
715 struct find_data data;
718 data.parent = parent;
723 bus_for_each_dev(&amba_bustype, NULL, &data, amba_find_match);
729 * amba_request_regions - request all mem regions associated with device
730 * @dev: amba_device structure for device
731 * @name: name, or NULL to use driver name
733 int amba_request_regions(struct amba_device *dev, const char *name)
739 name = dev->dev.driver->name;
741 size = resource_size(&dev->res);
743 if (!request_mem_region(dev->res.start, size, name))
750 * amba_release_regions - release mem regions associated with device
751 * @dev: amba_device structure for device
753 * Release regions claimed by a successful call to amba_request_regions.
755 void amba_release_regions(struct amba_device *dev)
759 size = resource_size(&dev->res);
760 release_mem_region(dev->res.start, size);
763 EXPORT_SYMBOL(amba_driver_register);
764 EXPORT_SYMBOL(amba_driver_unregister);
765 EXPORT_SYMBOL(amba_device_register);
766 EXPORT_SYMBOL(amba_device_unregister);
767 EXPORT_SYMBOL(amba_find_device);
768 EXPORT_SYMBOL(amba_request_regions);
769 EXPORT_SYMBOL(amba_release_regions);