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>
25 #define to_amba_driver(d) container_of(d, struct amba_driver, drv)
27 /* called on periphid match and class 0x9 coresight device. */
29 amba_cs_uci_id_match(const struct amba_id *table, struct amba_device *dev)
32 struct amba_cs_uci_id *uci;
36 /* no table data or zero mask - return match on periphid */
37 if (!uci || (uci->devarch_mask == 0))
40 /* test against read devtype and masked devarch value */
41 ret = (dev->uci.devtype == uci->devtype) &&
42 ((dev->uci.devarch & uci->devarch_mask) == uci->devarch);
46 static const struct amba_id *
47 amba_lookup(const struct amba_id *table, struct amba_device *dev)
50 if (((dev->periphid & table->mask) == table->id) &&
51 ((dev->cid != CORESIGHT_CID) ||
52 (amba_cs_uci_id_match(table, dev))))
59 static int amba_get_enable_pclk(struct amba_device *pcdev)
63 pcdev->pclk = clk_get(&pcdev->dev, "apb_pclk");
64 if (IS_ERR(pcdev->pclk))
65 return PTR_ERR(pcdev->pclk);
67 ret = clk_prepare_enable(pcdev->pclk);
74 static void amba_put_disable_pclk(struct amba_device *pcdev)
76 clk_disable_unprepare(pcdev->pclk);
81 static ssize_t driver_override_show(struct device *_dev,
82 struct device_attribute *attr, char *buf)
84 struct amba_device *dev = to_amba_device(_dev);
88 len = sprintf(buf, "%s\n", dev->driver_override);
93 static ssize_t driver_override_store(struct device *_dev,
94 struct device_attribute *attr,
95 const char *buf, size_t count)
97 struct amba_device *dev = to_amba_device(_dev);
98 char *driver_override, *old, *cp;
100 /* We need to keep extra room for a newline */
101 if (count >= (PAGE_SIZE - 1))
104 driver_override = kstrndup(buf, count, GFP_KERNEL);
105 if (!driver_override)
108 cp = strchr(driver_override, '\n');
113 old = dev->driver_override;
114 if (strlen(driver_override)) {
115 dev->driver_override = driver_override;
117 kfree(driver_override);
118 dev->driver_override = NULL;
126 static DEVICE_ATTR_RW(driver_override);
128 #define amba_attr_func(name,fmt,arg...) \
129 static ssize_t name##_show(struct device *_dev, \
130 struct device_attribute *attr, char *buf) \
132 struct amba_device *dev = to_amba_device(_dev); \
133 return sprintf(buf, fmt, arg); \
135 static DEVICE_ATTR_RO(name)
137 amba_attr_func(id, "%08x\n", dev->periphid);
138 amba_attr_func(irq0, "%u\n", dev->irq[0]);
139 amba_attr_func(irq1, "%u\n", dev->irq[1]);
140 amba_attr_func(resource, "\t%016llx\t%016llx\t%016lx\n",
141 (unsigned long long)dev->res.start, (unsigned long long)dev->res.end,
144 static struct attribute *amba_dev_attrs[] = {
146 &dev_attr_resource.attr,
147 &dev_attr_driver_override.attr,
150 ATTRIBUTE_GROUPS(amba_dev);
152 static int amba_match(struct device *dev, struct device_driver *drv)
154 struct amba_device *pcdev = to_amba_device(dev);
155 struct amba_driver *pcdrv = to_amba_driver(drv);
157 /* When driver_override is set, only bind to the matching driver */
158 if (pcdev->driver_override)
159 return !strcmp(pcdev->driver_override, drv->name);
161 return amba_lookup(pcdrv->id_table, pcdev) != NULL;
164 static int amba_uevent(struct device *dev, struct kobj_uevent_env *env)
166 struct amba_device *pcdev = to_amba_device(dev);
169 retval = add_uevent_var(env, "AMBA_ID=%08x", pcdev->periphid);
173 retval = add_uevent_var(env, "MODALIAS=amba:d%08X", pcdev->periphid);
178 * These are the device model conversion veneers; they convert the
179 * device model structures to our more specific structures.
181 static int amba_probe(struct device *dev)
183 struct amba_device *pcdev = to_amba_device(dev);
184 struct amba_driver *pcdrv = to_amba_driver(dev->driver);
185 const struct amba_id *id = amba_lookup(pcdrv->id_table, pcdev);
189 ret = of_clk_set_defaults(dev->of_node, false);
193 ret = dev_pm_domain_attach(dev, true);
197 ret = amba_get_enable_pclk(pcdev);
199 dev_pm_domain_detach(dev, true);
203 pm_runtime_get_noresume(dev);
204 pm_runtime_set_active(dev);
205 pm_runtime_enable(dev);
207 ret = pcdrv->probe(pcdev, id);
211 pm_runtime_disable(dev);
212 pm_runtime_set_suspended(dev);
213 pm_runtime_put_noidle(dev);
215 amba_put_disable_pclk(pcdev);
216 dev_pm_domain_detach(dev, true);
222 static void amba_remove(struct device *dev)
224 struct amba_device *pcdev = to_amba_device(dev);
225 struct amba_driver *drv = to_amba_driver(dev->driver);
227 pm_runtime_get_sync(dev);
230 pm_runtime_put_noidle(dev);
232 /* Undo the runtime PM settings in amba_probe() */
233 pm_runtime_disable(dev);
234 pm_runtime_set_suspended(dev);
235 pm_runtime_put_noidle(dev);
237 amba_put_disable_pclk(pcdev);
238 dev_pm_domain_detach(dev, true);
241 static void amba_shutdown(struct device *dev)
243 struct amba_driver *drv;
248 drv = to_amba_driver(dev->driver);
250 drv->shutdown(to_amba_device(dev));
255 * Hooks to provide runtime PM of the pclk (bus clock). It is safe to
256 * enable/disable the bus clock at runtime PM suspend/resume as this
257 * does not result in loss of context.
259 static int amba_pm_runtime_suspend(struct device *dev)
261 struct amba_device *pcdev = to_amba_device(dev);
262 int ret = pm_generic_runtime_suspend(dev);
264 if (ret == 0 && dev->driver) {
265 if (pm_runtime_is_irq_safe(dev))
266 clk_disable(pcdev->pclk);
268 clk_disable_unprepare(pcdev->pclk);
274 static int amba_pm_runtime_resume(struct device *dev)
276 struct amba_device *pcdev = to_amba_device(dev);
280 if (pm_runtime_is_irq_safe(dev))
281 ret = clk_enable(pcdev->pclk);
283 ret = clk_prepare_enable(pcdev->pclk);
284 /* Failure is probably fatal to the system, but... */
289 return pm_generic_runtime_resume(dev);
291 #endif /* CONFIG_PM */
293 static const struct dev_pm_ops amba_pm = {
294 .suspend = pm_generic_suspend,
295 .resume = pm_generic_resume,
296 .freeze = pm_generic_freeze,
297 .thaw = pm_generic_thaw,
298 .poweroff = pm_generic_poweroff,
299 .restore = pm_generic_restore,
301 amba_pm_runtime_suspend,
302 amba_pm_runtime_resume,
308 * Primecells are part of the Advanced Microcontroller Bus Architecture,
309 * so we call the bus "amba".
310 * DMA configuration for platform and AMBA bus is same. So here we reuse
311 * platform's DMA config routine.
313 struct bus_type amba_bustype = {
315 .dev_groups = amba_dev_groups,
317 .uevent = amba_uevent,
319 .remove = amba_remove,
320 .shutdown = amba_shutdown,
321 .dma_configure = platform_dma_configure,
324 EXPORT_SYMBOL_GPL(amba_bustype);
326 static int __init amba_init(void)
328 return bus_register(&amba_bustype);
331 postcore_initcall(amba_init);
334 * amba_driver_register - register an AMBA device driver
335 * @drv: amba device driver structure
337 * Register an AMBA device driver with the Linux device model
338 * core. If devices pre-exist, the drivers probe function will
341 int amba_driver_register(struct amba_driver *drv)
346 drv->drv.bus = &amba_bustype;
348 return driver_register(&drv->drv);
352 * amba_driver_unregister - remove an AMBA device driver
353 * @drv: AMBA device driver structure to remove
355 * Unregister an AMBA device driver from the Linux device
356 * model. The device model will call the drivers remove function
357 * for each device the device driver is currently handling.
359 void amba_driver_unregister(struct amba_driver *drv)
361 driver_unregister(&drv->drv);
365 static void amba_device_release(struct device *dev)
367 struct amba_device *d = to_amba_device(dev);
370 release_resource(&d->res);
374 static int amba_device_try_add(struct amba_device *dev, struct resource *parent)
380 WARN_ON(dev->irq[0] == (unsigned int)-1);
381 WARN_ON(dev->irq[1] == (unsigned int)-1);
383 ret = request_resource(parent, &dev->res);
387 /* Hard-coded primecell ID instead of plug-n-play */
388 if (dev->periphid != 0)
392 * Dynamically calculate the size of the resource
393 * and use this for iomap
395 size = resource_size(&dev->res);
396 tmp = ioremap(dev->res.start, size);
402 ret = dev_pm_domain_attach(&dev->dev, true);
408 ret = amba_get_enable_pclk(dev);
411 struct reset_control *rstc;
414 * Find reset control(s) of the amba bus and de-assert them.
416 rstc = of_reset_control_array_get_optional_shared(dev->dev.of_node);
419 if (ret != -EPROBE_DEFER)
420 dev_err(&dev->dev, "can't get reset: %d\n",
424 reset_control_deassert(rstc);
425 reset_control_put(rstc);
428 * Read pid and cid based on size of resource
429 * they are located at end of region
431 for (pid = 0, i = 0; i < 4; i++)
432 pid |= (readl(tmp + size - 0x20 + 4 * i) & 255) <<
434 for (cid = 0, i = 0; i < 4; i++)
435 cid |= (readl(tmp + size - 0x10 + 4 * i) & 255) <<
438 if (cid == CORESIGHT_CID) {
439 /* set the base to the start of the last 4k block */
440 void __iomem *csbase = tmp + size - 4096;
443 readl(csbase + UCI_REG_DEVARCH_OFFSET);
445 readl(csbase + UCI_REG_DEVTYPE_OFFSET) & 0xff;
448 amba_put_disable_pclk(dev);
450 if (cid == AMBA_CID || cid == CORESIGHT_CID) {
460 dev_pm_domain_detach(&dev->dev, true);
466 ret = device_add(&dev->dev);
471 ret = device_create_file(&dev->dev, &dev_attr_irq0);
472 if (ret == 0 && dev->irq[1])
473 ret = device_create_file(&dev->dev, &dev_attr_irq1);
477 device_unregister(&dev->dev);
480 release_resource(&dev->res);
485 amba_put_disable_pclk(dev);
487 dev_pm_domain_detach(&dev->dev, true);
492 * Registration of AMBA device require reading its pid and cid registers.
493 * To do this, the device must be turned on (if it is a part of power domain)
494 * and have clocks enabled. However in some cases those resources might not be
495 * yet available. Returning EPROBE_DEFER is not a solution in such case,
496 * because callers don't handle this special error code. Instead such devices
497 * are added to the special list and their registration is retried from
498 * periodic worker, until all resources are available and registration succeeds.
500 struct deferred_device {
501 struct amba_device *dev;
502 struct resource *parent;
503 struct list_head node;
506 static LIST_HEAD(deferred_devices);
507 static DEFINE_MUTEX(deferred_devices_lock);
509 static void amba_deferred_retry_func(struct work_struct *dummy);
510 static DECLARE_DELAYED_WORK(deferred_retry_work, amba_deferred_retry_func);
512 #define DEFERRED_DEVICE_TIMEOUT (msecs_to_jiffies(5 * 1000))
514 static int amba_deferred_retry(void)
516 struct deferred_device *ddev, *tmp;
518 mutex_lock(&deferred_devices_lock);
520 list_for_each_entry_safe(ddev, tmp, &deferred_devices, node) {
521 int ret = amba_device_try_add(ddev->dev, ddev->parent);
523 if (ret == -EPROBE_DEFER)
526 list_del_init(&ddev->node);
530 mutex_unlock(&deferred_devices_lock);
534 late_initcall(amba_deferred_retry);
536 static void amba_deferred_retry_func(struct work_struct *dummy)
538 amba_deferred_retry();
540 if (!list_empty(&deferred_devices))
541 schedule_delayed_work(&deferred_retry_work,
542 DEFERRED_DEVICE_TIMEOUT);
546 * amba_device_add - add a previously allocated AMBA device structure
547 * @dev: AMBA device allocated by amba_device_alloc
548 * @parent: resource parent for this devices resources
550 * Claim the resource, and read the device cell ID if not already
551 * initialized. Register the AMBA device with the Linux device
554 int amba_device_add(struct amba_device *dev, struct resource *parent)
556 int ret = amba_device_try_add(dev, parent);
558 if (ret == -EPROBE_DEFER) {
559 struct deferred_device *ddev;
561 ddev = kmalloc(sizeof(*ddev), GFP_KERNEL);
566 ddev->parent = parent;
569 mutex_lock(&deferred_devices_lock);
571 if (list_empty(&deferred_devices))
572 schedule_delayed_work(&deferred_retry_work,
573 DEFERRED_DEVICE_TIMEOUT);
574 list_add_tail(&ddev->node, &deferred_devices);
576 mutex_unlock(&deferred_devices_lock);
580 EXPORT_SYMBOL_GPL(amba_device_add);
582 static struct amba_device *
583 amba_aphb_device_add(struct device *parent, const char *name,
584 resource_size_t base, size_t size, int irq1, int irq2,
585 void *pdata, unsigned int periphid, u64 dma_mask,
586 struct resource *resbase)
588 struct amba_device *dev;
591 dev = amba_device_alloc(name, base, size);
593 return ERR_PTR(-ENOMEM);
595 dev->dev.coherent_dma_mask = dma_mask;
598 dev->periphid = periphid;
599 dev->dev.platform_data = pdata;
600 dev->dev.parent = parent;
602 ret = amba_device_add(dev, resbase);
604 amba_device_put(dev);
612 amba_apb_device_add(struct device *parent, const char *name,
613 resource_size_t base, size_t size, int irq1, int irq2,
614 void *pdata, unsigned int periphid)
616 return amba_aphb_device_add(parent, name, base, size, irq1, irq2, pdata,
617 periphid, 0, &iomem_resource);
619 EXPORT_SYMBOL_GPL(amba_apb_device_add);
622 amba_ahb_device_add(struct device *parent, const char *name,
623 resource_size_t base, size_t size, int irq1, int irq2,
624 void *pdata, unsigned int periphid)
626 return amba_aphb_device_add(parent, name, base, size, irq1, irq2, pdata,
627 periphid, ~0ULL, &iomem_resource);
629 EXPORT_SYMBOL_GPL(amba_ahb_device_add);
632 amba_apb_device_add_res(struct device *parent, const char *name,
633 resource_size_t base, size_t size, int irq1,
634 int irq2, void *pdata, unsigned int periphid,
635 struct resource *resbase)
637 return amba_aphb_device_add(parent, name, base, size, irq1, irq2, pdata,
638 periphid, 0, resbase);
640 EXPORT_SYMBOL_GPL(amba_apb_device_add_res);
643 amba_ahb_device_add_res(struct device *parent, const char *name,
644 resource_size_t base, size_t size, int irq1,
645 int irq2, void *pdata, unsigned int periphid,
646 struct resource *resbase)
648 return amba_aphb_device_add(parent, name, base, size, irq1, irq2, pdata,
649 periphid, ~0ULL, resbase);
651 EXPORT_SYMBOL_GPL(amba_ahb_device_add_res);
654 static void amba_device_initialize(struct amba_device *dev, const char *name)
656 device_initialize(&dev->dev);
658 dev_set_name(&dev->dev, "%s", name);
659 dev->dev.release = amba_device_release;
660 dev->dev.bus = &amba_bustype;
661 dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
662 dev->dev.dma_parms = &dev->dma_parms;
663 dev->res.name = dev_name(&dev->dev);
667 * amba_device_alloc - allocate an AMBA device
668 * @name: sysfs name of the AMBA device
669 * @base: base of AMBA device
670 * @size: size of AMBA device
672 * Allocate and initialize an AMBA device structure. Returns %NULL
675 struct amba_device *amba_device_alloc(const char *name, resource_size_t base,
678 struct amba_device *dev;
680 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
682 amba_device_initialize(dev, name);
683 dev->res.start = base;
684 dev->res.end = base + size - 1;
685 dev->res.flags = IORESOURCE_MEM;
690 EXPORT_SYMBOL_GPL(amba_device_alloc);
693 * amba_device_register - register an AMBA device
694 * @dev: AMBA device to register
695 * @parent: parent memory resource
697 * Setup the AMBA device, reading the cell ID if present.
698 * Claim the resource, and register the AMBA device with
699 * the Linux device manager.
701 int amba_device_register(struct amba_device *dev, struct resource *parent)
703 amba_device_initialize(dev, dev->dev.init_name);
704 dev->dev.init_name = NULL;
706 return amba_device_add(dev, parent);
710 * amba_device_put - put an AMBA device
711 * @dev: AMBA device to put
713 void amba_device_put(struct amba_device *dev)
715 put_device(&dev->dev);
717 EXPORT_SYMBOL_GPL(amba_device_put);
720 * amba_device_unregister - unregister an AMBA device
721 * @dev: AMBA device to remove
723 * Remove the specified AMBA device from the Linux device
724 * manager. All files associated with this object will be
725 * destroyed, and device drivers notified that the device has
726 * been removed. The AMBA device's resources including
727 * the amba_device structure will be freed once all
728 * references to it have been dropped.
730 void amba_device_unregister(struct amba_device *dev)
732 device_unregister(&dev->dev);
737 struct amba_device *dev;
738 struct device *parent;
744 static int amba_find_match(struct device *dev, void *data)
746 struct find_data *d = data;
747 struct amba_device *pcdev = to_amba_device(dev);
750 r = (pcdev->periphid & d->mask) == d->id;
752 r &= d->parent == dev->parent;
754 r &= strcmp(dev_name(dev), d->busid) == 0;
765 * amba_find_device - locate an AMBA device given a bus id
766 * @busid: bus id for device (or NULL)
767 * @parent: parent device (or NULL)
768 * @id: peripheral ID (or 0)
769 * @mask: peripheral ID mask (or 0)
771 * Return the AMBA device corresponding to the supplied parameters.
772 * If no device matches, returns NULL.
774 * NOTE: When a valid device is found, its refcount is
775 * incremented, and must be decremented before the returned
779 amba_find_device(const char *busid, struct device *parent, unsigned int id,
782 struct find_data data;
785 data.parent = parent;
790 bus_for_each_dev(&amba_bustype, NULL, &data, amba_find_match);
796 * amba_request_regions - request all mem regions associated with device
797 * @dev: amba_device structure for device
798 * @name: name, or NULL to use driver name
800 int amba_request_regions(struct amba_device *dev, const char *name)
806 name = dev->dev.driver->name;
808 size = resource_size(&dev->res);
810 if (!request_mem_region(dev->res.start, size, name))
817 * amba_release_regions - release mem regions associated with device
818 * @dev: amba_device structure for device
820 * Release regions claimed by a successful call to amba_request_regions.
822 void amba_release_regions(struct amba_device *dev)
826 size = resource_size(&dev->res);
827 release_mem_region(dev->res.start, size);
830 EXPORT_SYMBOL(amba_driver_register);
831 EXPORT_SYMBOL(amba_driver_unregister);
832 EXPORT_SYMBOL(amba_device_register);
833 EXPORT_SYMBOL(amba_device_unregister);
834 EXPORT_SYMBOL(amba_find_device);
835 EXPORT_SYMBOL(amba_request_regions);
836 EXPORT_SYMBOL(amba_release_regions);