1 // SPDX-License-Identifier: GPL-2.0-only
3 * linux/arch/arm/common/amba.c
5 * Copyright (C) 2003 Deep Blue Solutions Ltd, All Rights Reserved.
7 #include <linux/module.h>
8 #include <linux/init.h>
9 #include <linux/device.h>
10 #include <linux/string.h>
11 #include <linux/slab.h>
14 #include <linux/pm_runtime.h>
15 #include <linux/pm_domain.h>
16 #include <linux/amba/bus.h>
17 #include <linux/sizes.h>
18 #include <linux/limits.h>
19 #include <linux/clk/clk-conf.h>
20 #include <linux/platform_device.h>
21 #include <linux/reset.h>
22 #include <linux/of_irq.h>
24 #define to_amba_driver(d) container_of(d, struct amba_driver, drv)
26 /* called on periphid match and class 0x9 coresight device. */
28 amba_cs_uci_id_match(const struct amba_id *table, struct amba_device *dev)
31 struct amba_cs_uci_id *uci;
35 /* no table data or zero mask - return match on periphid */
36 if (!uci || (uci->devarch_mask == 0))
39 /* test against read devtype and masked devarch value */
40 ret = (dev->uci.devtype == uci->devtype) &&
41 ((dev->uci.devarch & uci->devarch_mask) == uci->devarch);
45 static const struct amba_id *
46 amba_lookup(const struct amba_id *table, struct amba_device *dev)
49 if (((dev->periphid & table->mask) == table->id) &&
50 ((dev->cid != CORESIGHT_CID) ||
51 (amba_cs_uci_id_match(table, dev))))
58 static int amba_get_enable_pclk(struct amba_device *pcdev)
62 pcdev->pclk = clk_get(&pcdev->dev, "apb_pclk");
63 if (IS_ERR(pcdev->pclk))
64 return PTR_ERR(pcdev->pclk);
66 ret = clk_prepare_enable(pcdev->pclk);
73 static void amba_put_disable_pclk(struct amba_device *pcdev)
75 clk_disable_unprepare(pcdev->pclk);
80 static ssize_t driver_override_show(struct device *_dev,
81 struct device_attribute *attr, char *buf)
83 struct amba_device *dev = to_amba_device(_dev);
87 len = sprintf(buf, "%s\n", dev->driver_override);
92 static ssize_t driver_override_store(struct device *_dev,
93 struct device_attribute *attr,
94 const char *buf, size_t count)
96 struct amba_device *dev = to_amba_device(_dev);
97 char *driver_override, *old, *cp;
99 /* We need to keep extra room for a newline */
100 if (count >= (PAGE_SIZE - 1))
103 driver_override = kstrndup(buf, count, GFP_KERNEL);
104 if (!driver_override)
107 cp = strchr(driver_override, '\n');
112 old = dev->driver_override;
113 if (strlen(driver_override)) {
114 dev->driver_override = driver_override;
116 kfree(driver_override);
117 dev->driver_override = NULL;
125 static DEVICE_ATTR_RW(driver_override);
127 #define amba_attr_func(name,fmt,arg...) \
128 static ssize_t name##_show(struct device *_dev, \
129 struct device_attribute *attr, char *buf) \
131 struct amba_device *dev = to_amba_device(_dev); \
132 return sprintf(buf, fmt, arg); \
134 static DEVICE_ATTR_RO(name)
136 amba_attr_func(id, "%08x\n", dev->periphid);
137 amba_attr_func(resource, "\t%016llx\t%016llx\t%016lx\n",
138 (unsigned long long)dev->res.start, (unsigned long long)dev->res.end,
141 static struct attribute *amba_dev_attrs[] = {
143 &dev_attr_resource.attr,
144 &dev_attr_driver_override.attr,
147 ATTRIBUTE_GROUPS(amba_dev);
149 static int amba_match(struct device *dev, struct device_driver *drv)
151 struct amba_device *pcdev = to_amba_device(dev);
152 struct amba_driver *pcdrv = to_amba_driver(drv);
154 /* When driver_override is set, only bind to the matching driver */
155 if (pcdev->driver_override)
156 return !strcmp(pcdev->driver_override, drv->name);
158 return amba_lookup(pcdrv->id_table, pcdev) != NULL;
161 static int amba_uevent(struct device *dev, struct kobj_uevent_env *env)
163 struct amba_device *pcdev = to_amba_device(dev);
166 retval = add_uevent_var(env, "AMBA_ID=%08x", pcdev->periphid);
170 retval = add_uevent_var(env, "MODALIAS=amba:d%08X", pcdev->periphid);
174 static int of_amba_device_decode_irq(struct amba_device *dev)
176 struct device_node *node = dev->dev.of_node;
179 if (IS_ENABLED(CONFIG_OF_IRQ) && node) {
180 /* Decode the IRQs and address ranges */
181 for (i = 0; i < AMBA_NR_IRQS; i++) {
182 irq = of_irq_get(node, i);
184 if (irq == -EPROBE_DEFER)
197 * These are the device model conversion veneers; they convert the
198 * device model structures to our more specific structures.
200 static int amba_probe(struct device *dev)
202 struct amba_device *pcdev = to_amba_device(dev);
203 struct amba_driver *pcdrv = to_amba_driver(dev->driver);
204 const struct amba_id *id = amba_lookup(pcdrv->id_table, pcdev);
208 ret = of_amba_device_decode_irq(pcdev);
212 ret = of_clk_set_defaults(dev->of_node, false);
216 ret = dev_pm_domain_attach(dev, true);
220 ret = amba_get_enable_pclk(pcdev);
222 dev_pm_domain_detach(dev, true);
226 pm_runtime_get_noresume(dev);
227 pm_runtime_set_active(dev);
228 pm_runtime_enable(dev);
230 ret = pcdrv->probe(pcdev, id);
234 pm_runtime_disable(dev);
235 pm_runtime_set_suspended(dev);
236 pm_runtime_put_noidle(dev);
238 amba_put_disable_pclk(pcdev);
239 dev_pm_domain_detach(dev, true);
245 static void amba_remove(struct device *dev)
247 struct amba_device *pcdev = to_amba_device(dev);
248 struct amba_driver *drv = to_amba_driver(dev->driver);
250 pm_runtime_get_sync(dev);
253 pm_runtime_put_noidle(dev);
255 /* Undo the runtime PM settings in amba_probe() */
256 pm_runtime_disable(dev);
257 pm_runtime_set_suspended(dev);
258 pm_runtime_put_noidle(dev);
260 amba_put_disable_pclk(pcdev);
261 dev_pm_domain_detach(dev, true);
264 static void amba_shutdown(struct device *dev)
266 struct amba_driver *drv;
271 drv = to_amba_driver(dev->driver);
273 drv->shutdown(to_amba_device(dev));
278 * Hooks to provide runtime PM of the pclk (bus clock). It is safe to
279 * enable/disable the bus clock at runtime PM suspend/resume as this
280 * does not result in loss of context.
282 static int amba_pm_runtime_suspend(struct device *dev)
284 struct amba_device *pcdev = to_amba_device(dev);
285 int ret = pm_generic_runtime_suspend(dev);
287 if (ret == 0 && dev->driver) {
288 if (pm_runtime_is_irq_safe(dev))
289 clk_disable(pcdev->pclk);
291 clk_disable_unprepare(pcdev->pclk);
297 static int amba_pm_runtime_resume(struct device *dev)
299 struct amba_device *pcdev = to_amba_device(dev);
303 if (pm_runtime_is_irq_safe(dev))
304 ret = clk_enable(pcdev->pclk);
306 ret = clk_prepare_enable(pcdev->pclk);
307 /* Failure is probably fatal to the system, but... */
312 return pm_generic_runtime_resume(dev);
314 #endif /* CONFIG_PM */
316 static const struct dev_pm_ops amba_pm = {
317 .suspend = pm_generic_suspend,
318 .resume = pm_generic_resume,
319 .freeze = pm_generic_freeze,
320 .thaw = pm_generic_thaw,
321 .poweroff = pm_generic_poweroff,
322 .restore = pm_generic_restore,
324 amba_pm_runtime_suspend,
325 amba_pm_runtime_resume,
331 * Primecells are part of the Advanced Microcontroller Bus Architecture,
332 * so we call the bus "amba".
333 * DMA configuration for platform and AMBA bus is same. So here we reuse
334 * platform's DMA config routine.
336 struct bus_type amba_bustype = {
338 .dev_groups = amba_dev_groups,
340 .uevent = amba_uevent,
342 .remove = amba_remove,
343 .shutdown = amba_shutdown,
344 .dma_configure = platform_dma_configure,
347 EXPORT_SYMBOL_GPL(amba_bustype);
349 static int __init amba_init(void)
351 return bus_register(&amba_bustype);
354 postcore_initcall(amba_init);
357 * amba_driver_register - register an AMBA device driver
358 * @drv: amba device driver structure
360 * Register an AMBA device driver with the Linux device model
361 * core. If devices pre-exist, the drivers probe function will
364 int amba_driver_register(struct amba_driver *drv)
369 drv->drv.bus = &amba_bustype;
371 return driver_register(&drv->drv);
375 * amba_driver_unregister - remove an AMBA device driver
376 * @drv: AMBA device driver structure to remove
378 * Unregister an AMBA device driver from the Linux device
379 * model. The device model will call the drivers remove function
380 * for each device the device driver is currently handling.
382 void amba_driver_unregister(struct amba_driver *drv)
384 driver_unregister(&drv->drv);
388 static void amba_device_release(struct device *dev)
390 struct amba_device *d = to_amba_device(dev);
393 release_resource(&d->res);
397 static int amba_device_try_add(struct amba_device *dev, struct resource *parent)
403 ret = request_resource(parent, &dev->res);
407 /* Hard-coded primecell ID instead of plug-n-play */
408 if (dev->periphid != 0)
412 * Dynamically calculate the size of the resource
413 * and use this for iomap
415 size = resource_size(&dev->res);
416 tmp = ioremap(dev->res.start, size);
422 ret = dev_pm_domain_attach(&dev->dev, true);
428 ret = amba_get_enable_pclk(dev);
431 struct reset_control *rstc;
434 * Find reset control(s) of the amba bus and de-assert them.
436 rstc = of_reset_control_array_get_optional_shared(dev->dev.of_node);
439 if (ret != -EPROBE_DEFER)
440 dev_err(&dev->dev, "can't get reset: %d\n",
444 reset_control_deassert(rstc);
445 reset_control_put(rstc);
448 * Read pid and cid based on size of resource
449 * they are located at end of region
451 for (pid = 0, i = 0; i < 4; i++)
452 pid |= (readl(tmp + size - 0x20 + 4 * i) & 255) <<
454 for (cid = 0, i = 0; i < 4; i++)
455 cid |= (readl(tmp + size - 0x10 + 4 * i) & 255) <<
458 if (cid == CORESIGHT_CID) {
459 /* set the base to the start of the last 4k block */
460 void __iomem *csbase = tmp + size - 4096;
463 readl(csbase + UCI_REG_DEVARCH_OFFSET);
465 readl(csbase + UCI_REG_DEVTYPE_OFFSET) & 0xff;
468 amba_put_disable_pclk(dev);
470 if (cid == AMBA_CID || cid == CORESIGHT_CID) {
480 dev_pm_domain_detach(&dev->dev, true);
486 ret = device_add(&dev->dev);
489 release_resource(&dev->res);
494 amba_put_disable_pclk(dev);
496 dev_pm_domain_detach(&dev->dev, true);
501 * Registration of AMBA device require reading its pid and cid registers.
502 * To do this, the device must be turned on (if it is a part of power domain)
503 * and have clocks enabled. However in some cases those resources might not be
504 * yet available. Returning EPROBE_DEFER is not a solution in such case,
505 * because callers don't handle this special error code. Instead such devices
506 * are added to the special list and their registration is retried from
507 * periodic worker, until all resources are available and registration succeeds.
509 struct deferred_device {
510 struct amba_device *dev;
511 struct resource *parent;
512 struct list_head node;
515 static LIST_HEAD(deferred_devices);
516 static DEFINE_MUTEX(deferred_devices_lock);
518 static void amba_deferred_retry_func(struct work_struct *dummy);
519 static DECLARE_DELAYED_WORK(deferred_retry_work, amba_deferred_retry_func);
521 #define DEFERRED_DEVICE_TIMEOUT (msecs_to_jiffies(5 * 1000))
523 static int amba_deferred_retry(void)
525 struct deferred_device *ddev, *tmp;
527 mutex_lock(&deferred_devices_lock);
529 list_for_each_entry_safe(ddev, tmp, &deferred_devices, node) {
530 int ret = amba_device_try_add(ddev->dev, ddev->parent);
532 if (ret == -EPROBE_DEFER)
535 list_del_init(&ddev->node);
539 mutex_unlock(&deferred_devices_lock);
543 late_initcall(amba_deferred_retry);
545 static void amba_deferred_retry_func(struct work_struct *dummy)
547 amba_deferred_retry();
549 if (!list_empty(&deferred_devices))
550 schedule_delayed_work(&deferred_retry_work,
551 DEFERRED_DEVICE_TIMEOUT);
555 * amba_device_add - add a previously allocated AMBA device structure
556 * @dev: AMBA device allocated by amba_device_alloc
557 * @parent: resource parent for this devices resources
559 * Claim the resource, and read the device cell ID if not already
560 * initialized. Register the AMBA device with the Linux device
563 int amba_device_add(struct amba_device *dev, struct resource *parent)
565 int ret = amba_device_try_add(dev, parent);
567 if (ret == -EPROBE_DEFER) {
568 struct deferred_device *ddev;
570 ddev = kmalloc(sizeof(*ddev), GFP_KERNEL);
575 ddev->parent = parent;
578 mutex_lock(&deferred_devices_lock);
580 if (list_empty(&deferred_devices))
581 schedule_delayed_work(&deferred_retry_work,
582 DEFERRED_DEVICE_TIMEOUT);
583 list_add_tail(&ddev->node, &deferred_devices);
585 mutex_unlock(&deferred_devices_lock);
589 EXPORT_SYMBOL_GPL(amba_device_add);
591 static void amba_device_initialize(struct amba_device *dev, const char *name)
593 device_initialize(&dev->dev);
595 dev_set_name(&dev->dev, "%s", name);
596 dev->dev.release = amba_device_release;
597 dev->dev.bus = &amba_bustype;
598 dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
599 dev->dev.dma_parms = &dev->dma_parms;
600 dev->res.name = dev_name(&dev->dev);
604 * amba_device_alloc - allocate an AMBA device
605 * @name: sysfs name of the AMBA device
606 * @base: base of AMBA device
607 * @size: size of AMBA device
609 * Allocate and initialize an AMBA device structure. Returns %NULL
612 struct amba_device *amba_device_alloc(const char *name, resource_size_t base,
615 struct amba_device *dev;
617 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
619 amba_device_initialize(dev, name);
620 dev->res.start = base;
621 dev->res.end = base + size - 1;
622 dev->res.flags = IORESOURCE_MEM;
627 EXPORT_SYMBOL_GPL(amba_device_alloc);
630 * amba_device_register - register an AMBA device
631 * @dev: AMBA device to register
632 * @parent: parent memory resource
634 * Setup the AMBA device, reading the cell ID if present.
635 * Claim the resource, and register the AMBA device with
636 * the Linux device manager.
638 int amba_device_register(struct amba_device *dev, struct resource *parent)
640 amba_device_initialize(dev, dev->dev.init_name);
641 dev->dev.init_name = NULL;
643 return amba_device_add(dev, parent);
647 * amba_device_put - put an AMBA device
648 * @dev: AMBA device to put
650 void amba_device_put(struct amba_device *dev)
652 put_device(&dev->dev);
654 EXPORT_SYMBOL_GPL(amba_device_put);
657 * amba_device_unregister - unregister an AMBA device
658 * @dev: AMBA device to remove
660 * Remove the specified AMBA device from the Linux device
661 * manager. All files associated with this object will be
662 * destroyed, and device drivers notified that the device has
663 * been removed. The AMBA device's resources including
664 * the amba_device structure will be freed once all
665 * references to it have been dropped.
667 void amba_device_unregister(struct amba_device *dev)
669 device_unregister(&dev->dev);
674 struct amba_device *dev;
675 struct device *parent;
681 static int amba_find_match(struct device *dev, void *data)
683 struct find_data *d = data;
684 struct amba_device *pcdev = to_amba_device(dev);
687 r = (pcdev->periphid & d->mask) == d->id;
689 r &= d->parent == dev->parent;
691 r &= strcmp(dev_name(dev), d->busid) == 0;
702 * amba_find_device - locate an AMBA device given a bus id
703 * @busid: bus id for device (or NULL)
704 * @parent: parent device (or NULL)
705 * @id: peripheral ID (or 0)
706 * @mask: peripheral ID mask (or 0)
708 * Return the AMBA device corresponding to the supplied parameters.
709 * If no device matches, returns NULL.
711 * NOTE: When a valid device is found, its refcount is
712 * incremented, and must be decremented before the returned
716 amba_find_device(const char *busid, struct device *parent, unsigned int id,
719 struct find_data data;
722 data.parent = parent;
727 bus_for_each_dev(&amba_bustype, NULL, &data, amba_find_match);
733 * amba_request_regions - request all mem regions associated with device
734 * @dev: amba_device structure for device
735 * @name: name, or NULL to use driver name
737 int amba_request_regions(struct amba_device *dev, const char *name)
743 name = dev->dev.driver->name;
745 size = resource_size(&dev->res);
747 if (!request_mem_region(dev->res.start, size, name))
754 * amba_release_regions - release mem regions associated with device
755 * @dev: amba_device structure for device
757 * Release regions claimed by a successful call to amba_request_regions.
759 void amba_release_regions(struct amba_device *dev)
763 size = resource_size(&dev->res);
764 release_mem_region(dev->res.start, size);
767 EXPORT_SYMBOL(amba_driver_register);
768 EXPORT_SYMBOL(amba_driver_unregister);
769 EXPORT_SYMBOL(amba_device_register);
770 EXPORT_SYMBOL(amba_device_unregister);
771 EXPORT_SYMBOL(amba_find_device);
772 EXPORT_SYMBOL(amba_request_regions);
773 EXPORT_SYMBOL(amba_release_regions);