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>
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_match(struct device *dev, struct device_driver *drv)
60 struct amba_device *pcdev = to_amba_device(dev);
61 struct amba_driver *pcdrv = to_amba_driver(drv);
63 /* When driver_override is set, only bind to the matching driver */
64 if (pcdev->driver_override)
65 return !strcmp(pcdev->driver_override, drv->name);
67 return amba_lookup(pcdrv->id_table, pcdev) != NULL;
70 static int amba_uevent(struct device *dev, struct kobj_uevent_env *env)
72 struct amba_device *pcdev = to_amba_device(dev);
75 retval = add_uevent_var(env, "AMBA_ID=%08x", pcdev->periphid);
79 retval = add_uevent_var(env, "MODALIAS=amba:d%08X", pcdev->periphid);
83 static ssize_t driver_override_show(struct device *_dev,
84 struct device_attribute *attr, char *buf)
86 struct amba_device *dev = to_amba_device(_dev);
90 len = sprintf(buf, "%s\n", dev->driver_override);
95 static ssize_t driver_override_store(struct device *_dev,
96 struct device_attribute *attr,
97 const char *buf, size_t count)
99 struct amba_device *dev = to_amba_device(_dev);
100 char *driver_override, *old, *cp;
102 /* We need to keep extra room for a newline */
103 if (count >= (PAGE_SIZE - 1))
106 driver_override = kstrndup(buf, count, GFP_KERNEL);
107 if (!driver_override)
110 cp = strchr(driver_override, '\n');
115 old = dev->driver_override;
116 if (strlen(driver_override)) {
117 dev->driver_override = driver_override;
119 kfree(driver_override);
120 dev->driver_override = NULL;
128 static DEVICE_ATTR_RW(driver_override);
130 #define amba_attr_func(name,fmt,arg...) \
131 static ssize_t name##_show(struct device *_dev, \
132 struct device_attribute *attr, char *buf) \
134 struct amba_device *dev = to_amba_device(_dev); \
135 return sprintf(buf, fmt, arg); \
137 static DEVICE_ATTR_RO(name)
139 amba_attr_func(id, "%08x\n", dev->periphid);
140 amba_attr_func(irq0, "%u\n", dev->irq[0]);
141 amba_attr_func(irq1, "%u\n", dev->irq[1]);
142 amba_attr_func(resource, "\t%016llx\t%016llx\t%016lx\n",
143 (unsigned long long)dev->res.start, (unsigned long long)dev->res.end,
146 static struct attribute *amba_dev_attrs[] = {
148 &dev_attr_resource.attr,
149 &dev_attr_driver_override.attr,
152 ATTRIBUTE_GROUPS(amba_dev);
156 * Hooks to provide runtime PM of the pclk (bus clock). It is safe to
157 * enable/disable the bus clock at runtime PM suspend/resume as this
158 * does not result in loss of context.
160 static int amba_pm_runtime_suspend(struct device *dev)
162 struct amba_device *pcdev = to_amba_device(dev);
163 int ret = pm_generic_runtime_suspend(dev);
165 if (ret == 0 && dev->driver) {
166 if (pm_runtime_is_irq_safe(dev))
167 clk_disable(pcdev->pclk);
169 clk_disable_unprepare(pcdev->pclk);
175 static int amba_pm_runtime_resume(struct device *dev)
177 struct amba_device *pcdev = to_amba_device(dev);
181 if (pm_runtime_is_irq_safe(dev))
182 ret = clk_enable(pcdev->pclk);
184 ret = clk_prepare_enable(pcdev->pclk);
185 /* Failure is probably fatal to the system, but... */
190 return pm_generic_runtime_resume(dev);
192 #endif /* CONFIG_PM */
194 static const struct dev_pm_ops amba_pm = {
195 .suspend = pm_generic_suspend,
196 .resume = pm_generic_resume,
197 .freeze = pm_generic_freeze,
198 .thaw = pm_generic_thaw,
199 .poweroff = pm_generic_poweroff,
200 .restore = pm_generic_restore,
202 amba_pm_runtime_suspend,
203 amba_pm_runtime_resume,
209 * Primecells are part of the Advanced Microcontroller Bus Architecture,
210 * so we call the bus "amba".
211 * DMA configuration for platform and AMBA bus is same. So here we reuse
212 * platform's DMA config routine.
214 struct bus_type amba_bustype = {
216 .dev_groups = amba_dev_groups,
218 .uevent = amba_uevent,
219 .dma_configure = platform_dma_configure,
222 EXPORT_SYMBOL_GPL(amba_bustype);
224 static int __init amba_init(void)
226 return bus_register(&amba_bustype);
229 postcore_initcall(amba_init);
231 static int amba_get_enable_pclk(struct amba_device *pcdev)
235 pcdev->pclk = clk_get(&pcdev->dev, "apb_pclk");
236 if (IS_ERR(pcdev->pclk))
237 return PTR_ERR(pcdev->pclk);
239 ret = clk_prepare_enable(pcdev->pclk);
241 clk_put(pcdev->pclk);
246 static void amba_put_disable_pclk(struct amba_device *pcdev)
248 clk_disable_unprepare(pcdev->pclk);
249 clk_put(pcdev->pclk);
253 * These are the device model conversion veneers; they convert the
254 * device model structures to our more specific structures.
256 static int amba_probe(struct device *dev)
258 struct amba_device *pcdev = to_amba_device(dev);
259 struct amba_driver *pcdrv = to_amba_driver(dev->driver);
260 const struct amba_id *id = amba_lookup(pcdrv->id_table, pcdev);
264 ret = of_clk_set_defaults(dev->of_node, false);
268 ret = dev_pm_domain_attach(dev, true);
272 ret = amba_get_enable_pclk(pcdev);
274 dev_pm_domain_detach(dev, true);
278 pm_runtime_get_noresume(dev);
279 pm_runtime_set_active(dev);
280 pm_runtime_enable(dev);
282 ret = pcdrv->probe(pcdev, id);
286 pm_runtime_disable(dev);
287 pm_runtime_set_suspended(dev);
288 pm_runtime_put_noidle(dev);
290 amba_put_disable_pclk(pcdev);
291 dev_pm_domain_detach(dev, true);
297 static int amba_remove(struct device *dev)
299 struct amba_device *pcdev = to_amba_device(dev);
300 struct amba_driver *drv = to_amba_driver(dev->driver);
303 pm_runtime_get_sync(dev);
304 ret = drv->remove(pcdev);
305 pm_runtime_put_noidle(dev);
307 /* Undo the runtime PM settings in amba_probe() */
308 pm_runtime_disable(dev);
309 pm_runtime_set_suspended(dev);
310 pm_runtime_put_noidle(dev);
312 amba_put_disable_pclk(pcdev);
313 dev_pm_domain_detach(dev, true);
318 static void amba_shutdown(struct device *dev)
320 struct amba_driver *drv = to_amba_driver(dev->driver);
321 drv->shutdown(to_amba_device(dev));
325 * amba_driver_register - register an AMBA device driver
326 * @drv: amba device driver structure
328 * Register an AMBA device driver with the Linux device model
329 * core. If devices pre-exist, the drivers probe function will
332 int amba_driver_register(struct amba_driver *drv)
334 drv->drv.bus = &amba_bustype;
336 #define SETFN(fn) if (drv->fn) drv->drv.fn = amba_##fn
341 return driver_register(&drv->drv);
345 * amba_driver_unregister - remove an AMBA device driver
346 * @drv: AMBA device driver structure to remove
348 * Unregister an AMBA device driver from the Linux device
349 * model. The device model will call the drivers remove function
350 * for each device the device driver is currently handling.
352 void amba_driver_unregister(struct amba_driver *drv)
354 driver_unregister(&drv->drv);
358 static void amba_device_release(struct device *dev)
360 struct amba_device *d = to_amba_device(dev);
363 release_resource(&d->res);
367 static int amba_device_try_add(struct amba_device *dev, struct resource *parent)
373 WARN_ON(dev->irq[0] == (unsigned int)-1);
374 WARN_ON(dev->irq[1] == (unsigned int)-1);
376 ret = request_resource(parent, &dev->res);
380 /* Hard-coded primecell ID instead of plug-n-play */
381 if (dev->periphid != 0)
385 * Dynamically calculate the size of the resource
386 * and use this for iomap
388 size = resource_size(&dev->res);
389 tmp = ioremap(dev->res.start, size);
395 ret = dev_pm_domain_attach(&dev->dev, true);
401 ret = amba_get_enable_pclk(dev);
406 * Read pid and cid based on size of resource
407 * they are located at end of region
409 for (pid = 0, i = 0; i < 4; i++)
410 pid |= (readl(tmp + size - 0x20 + 4 * i) & 255) <<
412 for (cid = 0, i = 0; i < 4; i++)
413 cid |= (readl(tmp + size - 0x10 + 4 * i) & 255) <<
416 if (cid == CORESIGHT_CID) {
417 /* set the base to the start of the last 4k block */
418 void __iomem *csbase = tmp + size - 4096;
421 readl(csbase + UCI_REG_DEVARCH_OFFSET);
423 readl(csbase + UCI_REG_DEVTYPE_OFFSET) & 0xff;
426 amba_put_disable_pclk(dev);
428 if (cid == AMBA_CID || cid == CORESIGHT_CID) {
438 dev_pm_domain_detach(&dev->dev, true);
444 ret = device_add(&dev->dev);
449 ret = device_create_file(&dev->dev, &dev_attr_irq0);
450 if (ret == 0 && dev->irq[1])
451 ret = device_create_file(&dev->dev, &dev_attr_irq1);
455 device_unregister(&dev->dev);
458 release_resource(&dev->res);
464 * Registration of AMBA device require reading its pid and cid registers.
465 * To do this, the device must be turned on (if it is a part of power domain)
466 * and have clocks enabled. However in some cases those resources might not be
467 * yet available. Returning EPROBE_DEFER is not a solution in such case,
468 * because callers don't handle this special error code. Instead such devices
469 * are added to the special list and their registration is retried from
470 * periodic worker, until all resources are available and registration succeeds.
472 struct deferred_device {
473 struct amba_device *dev;
474 struct resource *parent;
475 struct list_head node;
478 static LIST_HEAD(deferred_devices);
479 static DEFINE_MUTEX(deferred_devices_lock);
481 static void amba_deferred_retry_func(struct work_struct *dummy);
482 static DECLARE_DELAYED_WORK(deferred_retry_work, amba_deferred_retry_func);
484 #define DEFERRED_DEVICE_TIMEOUT (msecs_to_jiffies(5 * 1000))
486 static void amba_deferred_retry_func(struct work_struct *dummy)
488 struct deferred_device *ddev, *tmp;
490 mutex_lock(&deferred_devices_lock);
492 list_for_each_entry_safe(ddev, tmp, &deferred_devices, node) {
493 int ret = amba_device_try_add(ddev->dev, ddev->parent);
495 if (ret == -EPROBE_DEFER)
498 list_del_init(&ddev->node);
502 if (!list_empty(&deferred_devices))
503 schedule_delayed_work(&deferred_retry_work,
504 DEFERRED_DEVICE_TIMEOUT);
506 mutex_unlock(&deferred_devices_lock);
510 * amba_device_add - add a previously allocated AMBA device structure
511 * @dev: AMBA device allocated by amba_device_alloc
512 * @parent: resource parent for this devices resources
514 * Claim the resource, and read the device cell ID if not already
515 * initialized. Register the AMBA device with the Linux device
518 int amba_device_add(struct amba_device *dev, struct resource *parent)
520 int ret = amba_device_try_add(dev, parent);
522 if (ret == -EPROBE_DEFER) {
523 struct deferred_device *ddev;
525 ddev = kmalloc(sizeof(*ddev), GFP_KERNEL);
530 ddev->parent = parent;
533 mutex_lock(&deferred_devices_lock);
535 if (list_empty(&deferred_devices))
536 schedule_delayed_work(&deferred_retry_work,
537 DEFERRED_DEVICE_TIMEOUT);
538 list_add_tail(&ddev->node, &deferred_devices);
540 mutex_unlock(&deferred_devices_lock);
544 EXPORT_SYMBOL_GPL(amba_device_add);
546 static struct amba_device *
547 amba_aphb_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, u64 dma_mask,
550 struct resource *resbase)
552 struct amba_device *dev;
555 dev = amba_device_alloc(name, base, size);
557 return ERR_PTR(-ENOMEM);
559 dev->dev.coherent_dma_mask = dma_mask;
562 dev->periphid = periphid;
563 dev->dev.platform_data = pdata;
564 dev->dev.parent = parent;
566 ret = amba_device_add(dev, resbase);
568 amba_device_put(dev);
576 amba_apb_device_add(struct device *parent, const char *name,
577 resource_size_t base, size_t size, int irq1, int irq2,
578 void *pdata, unsigned int periphid)
580 return amba_aphb_device_add(parent, name, base, size, irq1, irq2, pdata,
581 periphid, 0, &iomem_resource);
583 EXPORT_SYMBOL_GPL(amba_apb_device_add);
586 amba_ahb_device_add(struct device *parent, const char *name,
587 resource_size_t base, size_t size, int irq1, int irq2,
588 void *pdata, unsigned int periphid)
590 return amba_aphb_device_add(parent, name, base, size, irq1, irq2, pdata,
591 periphid, ~0ULL, &iomem_resource);
593 EXPORT_SYMBOL_GPL(amba_ahb_device_add);
596 amba_apb_device_add_res(struct device *parent, const char *name,
597 resource_size_t base, size_t size, int irq1,
598 int irq2, void *pdata, unsigned int periphid,
599 struct resource *resbase)
601 return amba_aphb_device_add(parent, name, base, size, irq1, irq2, pdata,
602 periphid, 0, resbase);
604 EXPORT_SYMBOL_GPL(amba_apb_device_add_res);
607 amba_ahb_device_add_res(struct device *parent, const char *name,
608 resource_size_t base, size_t size, int irq1,
609 int irq2, void *pdata, unsigned int periphid,
610 struct resource *resbase)
612 return amba_aphb_device_add(parent, name, base, size, irq1, irq2, pdata,
613 periphid, ~0ULL, resbase);
615 EXPORT_SYMBOL_GPL(amba_ahb_device_add_res);
618 static void amba_device_initialize(struct amba_device *dev, const char *name)
620 device_initialize(&dev->dev);
622 dev_set_name(&dev->dev, "%s", name);
623 dev->dev.release = amba_device_release;
624 dev->dev.bus = &amba_bustype;
625 dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
626 dev->res.name = dev_name(&dev->dev);
630 * amba_device_alloc - allocate an AMBA device
631 * @name: sysfs name of the AMBA device
632 * @base: base of AMBA device
633 * @size: size of AMBA device
635 * Allocate and initialize an AMBA device structure. Returns %NULL
638 struct amba_device *amba_device_alloc(const char *name, resource_size_t base,
641 struct amba_device *dev;
643 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
645 amba_device_initialize(dev, name);
646 dev->res.start = base;
647 dev->res.end = base + size - 1;
648 dev->res.flags = IORESOURCE_MEM;
653 EXPORT_SYMBOL_GPL(amba_device_alloc);
656 * amba_device_register - register an AMBA device
657 * @dev: AMBA device to register
658 * @parent: parent memory resource
660 * Setup the AMBA device, reading the cell ID if present.
661 * Claim the resource, and register the AMBA device with
662 * the Linux device manager.
664 int amba_device_register(struct amba_device *dev, struct resource *parent)
666 amba_device_initialize(dev, dev->dev.init_name);
667 dev->dev.init_name = NULL;
669 return amba_device_add(dev, parent);
673 * amba_device_put - put an AMBA device
674 * @dev: AMBA device to put
676 void amba_device_put(struct amba_device *dev)
678 put_device(&dev->dev);
680 EXPORT_SYMBOL_GPL(amba_device_put);
683 * amba_device_unregister - unregister an AMBA device
684 * @dev: AMBA device to remove
686 * Remove the specified AMBA device from the Linux device
687 * manager. All files associated with this object will be
688 * destroyed, and device drivers notified that the device has
689 * been removed. The AMBA device's resources including
690 * the amba_device structure will be freed once all
691 * references to it have been dropped.
693 void amba_device_unregister(struct amba_device *dev)
695 device_unregister(&dev->dev);
700 struct amba_device *dev;
701 struct device *parent;
707 static int amba_find_match(struct device *dev, void *data)
709 struct find_data *d = data;
710 struct amba_device *pcdev = to_amba_device(dev);
713 r = (pcdev->periphid & d->mask) == d->id;
715 r &= d->parent == dev->parent;
717 r &= strcmp(dev_name(dev), d->busid) == 0;
728 * amba_find_device - locate an AMBA device given a bus id
729 * @busid: bus id for device (or NULL)
730 * @parent: parent device (or NULL)
731 * @id: peripheral ID (or 0)
732 * @mask: peripheral ID mask (or 0)
734 * Return the AMBA device corresponding to the supplied parameters.
735 * If no device matches, returns NULL.
737 * NOTE: When a valid device is found, its refcount is
738 * incremented, and must be decremented before the returned
742 amba_find_device(const char *busid, struct device *parent, unsigned int id,
745 struct find_data data;
748 data.parent = parent;
753 bus_for_each_dev(&amba_bustype, NULL, &data, amba_find_match);
759 * amba_request_regions - request all mem regions associated with device
760 * @dev: amba_device structure for device
761 * @name: name, or NULL to use driver name
763 int amba_request_regions(struct amba_device *dev, const char *name)
769 name = dev->dev.driver->name;
771 size = resource_size(&dev->res);
773 if (!request_mem_region(dev->res.start, size, name))
780 * amba_release_regions - release mem regions associated with device
781 * @dev: amba_device structure for device
783 * Release regions claimed by a successful call to amba_request_regions.
785 void amba_release_regions(struct amba_device *dev)
789 size = resource_size(&dev->res);
790 release_mem_region(dev->res.start, size);
793 EXPORT_SYMBOL(amba_driver_register);
794 EXPORT_SYMBOL(amba_driver_unregister);
795 EXPORT_SYMBOL(amba_device_register);
796 EXPORT_SYMBOL(amba_device_unregister);
797 EXPORT_SYMBOL(amba_find_device);
798 EXPORT_SYMBOL(amba_request_regions);
799 EXPORT_SYMBOL(amba_release_regions);