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;
114 #define amba_attr_func(name,fmt,arg...) \
115 static ssize_t name##_show(struct device *_dev, \
116 struct device_attribute *attr, char *buf) \
118 struct amba_device *dev = to_amba_device(_dev); \
119 return sprintf(buf, fmt, arg); \
122 #define amba_attr(name,fmt,arg...) \
123 amba_attr_func(name,fmt,arg) \
124 static DEVICE_ATTR(name, S_IRUGO, name##_show, NULL)
126 amba_attr_func(id, "%08x\n", dev->periphid);
127 amba_attr(irq0, "%u\n", dev->irq[0]);
128 amba_attr(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 device_attribute amba_dev_attrs[] = {
136 __ATTR_RW(driver_override),
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".
198 struct bus_type amba_bustype = {
200 .dev_attrs = amba_dev_attrs,
202 .uevent = amba_uevent,
206 static int __init amba_init(void)
208 return bus_register(&amba_bustype);
211 postcore_initcall(amba_init);
213 static int amba_get_enable_pclk(struct amba_device *pcdev)
217 pcdev->pclk = clk_get(&pcdev->dev, "apb_pclk");
218 if (IS_ERR(pcdev->pclk))
219 return PTR_ERR(pcdev->pclk);
221 ret = clk_prepare_enable(pcdev->pclk);
223 clk_put(pcdev->pclk);
228 static void amba_put_disable_pclk(struct amba_device *pcdev)
230 clk_disable_unprepare(pcdev->pclk);
231 clk_put(pcdev->pclk);
235 * These are the device model conversion veneers; they convert the
236 * device model structures to our more specific structures.
238 static int amba_probe(struct device *dev)
240 struct amba_device *pcdev = to_amba_device(dev);
241 struct amba_driver *pcdrv = to_amba_driver(dev->driver);
242 const struct amba_id *id = amba_lookup(pcdrv->id_table, pcdev);
246 ret = of_clk_set_defaults(dev->of_node, false);
250 ret = dev_pm_domain_attach(dev, true);
251 if (ret == -EPROBE_DEFER)
254 ret = amba_get_enable_pclk(pcdev);
256 dev_pm_domain_detach(dev, true);
260 pm_runtime_get_noresume(dev);
261 pm_runtime_set_active(dev);
262 pm_runtime_enable(dev);
264 ret = pcdrv->probe(pcdev, id);
268 pm_runtime_disable(dev);
269 pm_runtime_set_suspended(dev);
270 pm_runtime_put_noidle(dev);
272 amba_put_disable_pclk(pcdev);
273 dev_pm_domain_detach(dev, true);
279 static int amba_remove(struct device *dev)
281 struct amba_device *pcdev = to_amba_device(dev);
282 struct amba_driver *drv = to_amba_driver(dev->driver);
285 pm_runtime_get_sync(dev);
287 ret = drv->remove(pcdev);
288 pm_runtime_put_noidle(dev);
290 /* Undo the runtime PM settings in amba_probe() */
291 pm_runtime_disable(dev);
292 pm_runtime_set_suspended(dev);
293 pm_runtime_put_noidle(dev);
295 amba_put_disable_pclk(pcdev);
296 dev_pm_domain_detach(dev, true);
301 static void amba_shutdown(struct device *dev)
303 struct amba_driver *drv = to_amba_driver(dev->driver);
306 drv->shutdown(to_amba_device(dev));
310 * amba_driver_register - register an AMBA device driver
311 * @drv: amba device driver structure
313 * Register an AMBA device driver with the Linux device model
314 * core. If devices pre-exist, the drivers probe function will
317 int amba_driver_register(struct amba_driver *drv)
322 drv->drv.bus = &amba_bustype;
323 drv->drv.probe = amba_probe;
324 drv->drv.remove = amba_remove;
325 drv->drv.shutdown = amba_shutdown;
327 return driver_register(&drv->drv);
331 * amba_driver_unregister - remove an AMBA device driver
332 * @drv: AMBA device driver structure to remove
334 * Unregister an AMBA device driver from the Linux device
335 * model. The device model will call the drivers remove function
336 * for each device the device driver is currently handling.
338 void amba_driver_unregister(struct amba_driver *drv)
340 driver_unregister(&drv->drv);
344 static void amba_device_release(struct device *dev)
346 struct amba_device *d = to_amba_device(dev);
349 release_resource(&d->res);
353 static int amba_device_try_add(struct amba_device *dev, struct resource *parent)
359 ret = request_resource(parent, &dev->res);
363 /* Hard-coded primecell ID instead of plug-n-play */
364 if (dev->periphid != 0)
368 * Dynamically calculate the size of the resource
369 * and use this for iomap
371 size = resource_size(&dev->res);
372 tmp = ioremap(dev->res.start, size);
378 ret = dev_pm_domain_attach(&dev->dev, true);
379 if (ret == -EPROBE_DEFER) {
384 ret = amba_get_enable_pclk(dev);
389 * Read pid and cid based on size of resource
390 * they are located at end of region
392 for (pid = 0, i = 0; i < 4; i++)
393 pid |= (readl(tmp + size - 0x20 + 4 * i) & 255) <<
395 for (cid = 0, i = 0; i < 4; i++)
396 cid |= (readl(tmp + size - 0x10 + 4 * i) & 255) <<
399 amba_put_disable_pclk(dev);
401 if (cid == AMBA_CID || cid == CORESIGHT_CID)
409 dev_pm_domain_detach(&dev->dev, true);
415 ret = device_add(&dev->dev);
420 ret = device_create_file(&dev->dev, &dev_attr_irq0);
421 if (ret == 0 && dev->irq[1])
422 ret = device_create_file(&dev->dev, &dev_attr_irq1);
426 device_unregister(&dev->dev);
429 release_resource(&dev->res);
435 * Registration of AMBA device require reading its pid and cid registers.
436 * To do this, the device must be turned on (if it is a part of power domain)
437 * and have clocks enabled. However in some cases those resources might not be
438 * yet available. Returning EPROBE_DEFER is not a solution in such case,
439 * because callers don't handle this special error code. Instead such devices
440 * are added to the special list and their registration is retried from
441 * periodic worker, until all resources are available and registration succeeds.
443 struct deferred_device {
444 struct amba_device *dev;
445 struct resource *parent;
446 struct list_head node;
449 static LIST_HEAD(deferred_devices);
450 static DEFINE_MUTEX(deferred_devices_lock);
452 static void amba_deferred_retry_func(struct work_struct *dummy);
453 static DECLARE_DELAYED_WORK(deferred_retry_work, amba_deferred_retry_func);
455 #define DEFERRED_DEVICE_TIMEOUT (msecs_to_jiffies(5 * 1000))
457 static void amba_deferred_retry_func(struct work_struct *dummy)
459 struct deferred_device *ddev, *tmp;
461 mutex_lock(&deferred_devices_lock);
463 list_for_each_entry_safe(ddev, tmp, &deferred_devices, node) {
464 int ret = amba_device_try_add(ddev->dev, ddev->parent);
466 if (ret == -EPROBE_DEFER)
469 list_del_init(&ddev->node);
473 if (!list_empty(&deferred_devices))
474 schedule_delayed_work(&deferred_retry_work,
475 DEFERRED_DEVICE_TIMEOUT);
477 mutex_unlock(&deferred_devices_lock);
481 * amba_device_add - add a previously allocated AMBA device structure
482 * @dev: AMBA device allocated by amba_device_alloc
483 * @parent: resource parent for this devices resources
485 * Claim the resource, and read the device cell ID if not already
486 * initialized. Register the AMBA device with the Linux device
489 int amba_device_add(struct amba_device *dev, struct resource *parent)
491 int ret = amba_device_try_add(dev, parent);
493 if (ret == -EPROBE_DEFER) {
494 struct deferred_device *ddev;
496 ddev = kmalloc(sizeof(*ddev), GFP_KERNEL);
501 ddev->parent = parent;
504 mutex_lock(&deferred_devices_lock);
506 if (list_empty(&deferred_devices))
507 schedule_delayed_work(&deferred_retry_work,
508 DEFERRED_DEVICE_TIMEOUT);
509 list_add_tail(&ddev->node, &deferred_devices);
511 mutex_unlock(&deferred_devices_lock);
515 EXPORT_SYMBOL_GPL(amba_device_add);
517 static struct amba_device *
518 amba_aphb_device_add(struct device *parent, const char *name,
519 resource_size_t base, size_t size, int irq1, int irq2,
520 void *pdata, unsigned int periphid, u64 dma_mask,
521 struct resource *resbase)
523 struct amba_device *dev;
526 dev = amba_device_alloc(name, base, size);
528 return ERR_PTR(-ENOMEM);
530 dev->dev.coherent_dma_mask = dma_mask;
533 dev->periphid = periphid;
534 dev->dev.platform_data = pdata;
535 dev->dev.parent = parent;
537 ret = amba_device_add(dev, resbase);
539 amba_device_put(dev);
547 amba_apb_device_add(struct device *parent, const char *name,
548 resource_size_t base, size_t size, int irq1, int irq2,
549 void *pdata, unsigned int periphid)
551 return amba_aphb_device_add(parent, name, base, size, irq1, irq2, pdata,
552 periphid, 0, &iomem_resource);
554 EXPORT_SYMBOL_GPL(amba_apb_device_add);
557 amba_ahb_device_add(struct device *parent, const char *name,
558 resource_size_t base, size_t size, int irq1, int irq2,
559 void *pdata, unsigned int periphid)
561 return amba_aphb_device_add(parent, name, base, size, irq1, irq2, pdata,
562 periphid, ~0ULL, &iomem_resource);
564 EXPORT_SYMBOL_GPL(amba_ahb_device_add);
567 amba_apb_device_add_res(struct device *parent, const char *name,
568 resource_size_t base, size_t size, int irq1,
569 int irq2, void *pdata, unsigned int periphid,
570 struct resource *resbase)
572 return amba_aphb_device_add(parent, name, base, size, irq1, irq2, pdata,
573 periphid, 0, resbase);
575 EXPORT_SYMBOL_GPL(amba_apb_device_add_res);
578 amba_ahb_device_add_res(struct device *parent, const char *name,
579 resource_size_t base, size_t size, int irq1,
580 int irq2, void *pdata, unsigned int periphid,
581 struct resource *resbase)
583 return amba_aphb_device_add(parent, name, base, size, irq1, irq2, pdata,
584 periphid, ~0ULL, resbase);
586 EXPORT_SYMBOL_GPL(amba_ahb_device_add_res);
589 static void amba_device_initialize(struct amba_device *dev, const char *name)
591 device_initialize(&dev->dev);
593 dev_set_name(&dev->dev, "%s", name);
594 dev->dev.release = amba_device_release;
595 dev->dev.bus = &amba_bustype;
596 dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
597 dev->res.name = dev_name(&dev->dev);
601 * amba_device_alloc - allocate an AMBA device
602 * @name: sysfs name of the AMBA device
603 * @base: base of AMBA device
604 * @size: size of AMBA device
606 * Allocate and initialize an AMBA device structure. Returns %NULL
609 struct amba_device *amba_device_alloc(const char *name, resource_size_t base,
612 struct amba_device *dev;
614 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
616 amba_device_initialize(dev, name);
617 dev->res.start = base;
618 dev->res.end = base + size - 1;
619 dev->res.flags = IORESOURCE_MEM;
624 EXPORT_SYMBOL_GPL(amba_device_alloc);
627 * amba_device_register - register an AMBA device
628 * @dev: AMBA device to register
629 * @parent: parent memory resource
631 * Setup the AMBA device, reading the cell ID if present.
632 * Claim the resource, and register the AMBA device with
633 * the Linux device manager.
635 int amba_device_register(struct amba_device *dev, struct resource *parent)
637 amba_device_initialize(dev, dev->dev.init_name);
638 dev->dev.init_name = NULL;
640 return amba_device_add(dev, parent);
644 * amba_device_put - put an AMBA device
645 * @dev: AMBA device to put
647 void amba_device_put(struct amba_device *dev)
649 put_device(&dev->dev);
651 EXPORT_SYMBOL_GPL(amba_device_put);
654 * amba_device_unregister - unregister an AMBA device
655 * @dev: AMBA device to remove
657 * Remove the specified AMBA device from the Linux device
658 * manager. All files associated with this object will be
659 * destroyed, and device drivers notified that the device has
660 * been removed. The AMBA device's resources including
661 * the amba_device structure will be freed once all
662 * references to it have been dropped.
664 void amba_device_unregister(struct amba_device *dev)
666 device_unregister(&dev->dev);
671 struct amba_device *dev;
672 struct device *parent;
678 static int amba_find_match(struct device *dev, void *data)
680 struct find_data *d = data;
681 struct amba_device *pcdev = to_amba_device(dev);
684 r = (pcdev->periphid & d->mask) == d->id;
686 r &= d->parent == dev->parent;
688 r &= strcmp(dev_name(dev), d->busid) == 0;
699 * amba_find_device - locate an AMBA device given a bus id
700 * @busid: bus id for device (or NULL)
701 * @parent: parent device (or NULL)
702 * @id: peripheral ID (or 0)
703 * @mask: peripheral ID mask (or 0)
705 * Return the AMBA device corresponding to the supplied parameters.
706 * If no device matches, returns NULL.
708 * NOTE: When a valid device is found, its refcount is
709 * incremented, and must be decremented before the returned
713 amba_find_device(const char *busid, struct device *parent, unsigned int id,
716 struct find_data data;
719 data.parent = parent;
724 bus_for_each_dev(&amba_bustype, NULL, &data, amba_find_match);
730 * amba_request_regions - request all mem regions associated with device
731 * @dev: amba_device structure for device
732 * @name: name, or NULL to use driver name
734 int amba_request_regions(struct amba_device *dev, const char *name)
740 name = dev->dev.driver->name;
742 size = resource_size(&dev->res);
744 if (!request_mem_region(dev->res.start, size, name))
751 * amba_release_regions - release mem regions associated with device
752 * @dev: amba_device structure for device
754 * Release regions claimed by a successful call to amba_request_regions.
756 void amba_release_regions(struct amba_device *dev)
760 size = resource_size(&dev->res);
761 release_mem_region(dev->res.start, size);
764 EXPORT_SYMBOL(amba_driver_register);
765 EXPORT_SYMBOL(amba_driver_unregister);
766 EXPORT_SYMBOL(amba_device_register);
767 EXPORT_SYMBOL(amba_device_unregister);
768 EXPORT_SYMBOL(amba_find_device);
769 EXPORT_SYMBOL(amba_request_regions);
770 EXPORT_SYMBOL(amba_release_regions);