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/property.h>
22 #include <linux/reset.h>
23 #include <linux/of_irq.h>
24 #include <linux/of_device.h>
25 #include <linux/acpi.h>
26 #include <linux/iommu.h>
27 #include <linux/dma-map-ops.h>
29 #define to_amba_driver(d) container_of(d, struct amba_driver, drv)
31 /* called on periphid match and class 0x9 coresight device. */
33 amba_cs_uci_id_match(const struct amba_id *table, struct amba_device *dev)
36 struct amba_cs_uci_id *uci;
40 /* no table data or zero mask - return match on periphid */
41 if (!uci || (uci->devarch_mask == 0))
44 /* test against read devtype and masked devarch value */
45 ret = (dev->uci.devtype == uci->devtype) &&
46 ((dev->uci.devarch & uci->devarch_mask) == uci->devarch);
50 static const struct amba_id *
51 amba_lookup(const struct amba_id *table, struct amba_device *dev)
54 if (((dev->periphid & table->mask) == table->id) &&
55 ((dev->cid != CORESIGHT_CID) ||
56 (amba_cs_uci_id_match(table, dev))))
63 static int amba_get_enable_pclk(struct amba_device *pcdev)
67 pcdev->pclk = clk_get(&pcdev->dev, "apb_pclk");
68 if (IS_ERR(pcdev->pclk))
69 return PTR_ERR(pcdev->pclk);
71 ret = clk_prepare_enable(pcdev->pclk);
78 static void amba_put_disable_pclk(struct amba_device *pcdev)
80 clk_disable_unprepare(pcdev->pclk);
85 static ssize_t driver_override_show(struct device *_dev,
86 struct device_attribute *attr, char *buf)
88 struct amba_device *dev = to_amba_device(_dev);
92 len = sprintf(buf, "%s\n", dev->driver_override);
97 static ssize_t driver_override_store(struct device *_dev,
98 struct device_attribute *attr,
99 const char *buf, size_t count)
101 struct amba_device *dev = to_amba_device(_dev);
104 ret = driver_set_override(_dev, &dev->driver_override, buf, count);
110 static DEVICE_ATTR_RW(driver_override);
112 #define amba_attr_func(name,fmt,arg...) \
113 static ssize_t name##_show(struct device *_dev, \
114 struct device_attribute *attr, char *buf) \
116 struct amba_device *dev = to_amba_device(_dev); \
117 return sprintf(buf, fmt, arg); \
119 static DEVICE_ATTR_RO(name)
121 amba_attr_func(id, "%08x\n", dev->periphid);
122 amba_attr_func(resource, "\t%016llx\t%016llx\t%016lx\n",
123 (unsigned long long)dev->res.start, (unsigned long long)dev->res.end,
126 static struct attribute *amba_dev_attrs[] = {
128 &dev_attr_resource.attr,
129 &dev_attr_driver_override.attr,
132 ATTRIBUTE_GROUPS(amba_dev);
134 static int amba_read_periphid(struct amba_device *dev)
136 struct reset_control *rstc;
141 ret = dev_pm_domain_attach(&dev->dev, true);
143 dev_dbg(&dev->dev, "can't get PM domain: %d\n", ret);
147 ret = amba_get_enable_pclk(dev);
149 dev_dbg(&dev->dev, "can't get pclk: %d\n", ret);
154 * Find reset control(s) of the amba bus and de-assert them.
156 rstc = of_reset_control_array_get_optional_shared(dev->dev.of_node);
159 if (ret != -EPROBE_DEFER)
160 dev_err(&dev->dev, "can't get reset: %d\n", ret);
163 reset_control_deassert(rstc);
164 reset_control_put(rstc);
166 size = resource_size(&dev->res);
167 tmp = ioremap(dev->res.start, size);
174 * Read pid and cid based on size of resource
175 * they are located at end of region
177 for (pid = 0, i = 0; i < 4; i++)
178 pid |= (readl(tmp + size - 0x20 + 4 * i) & 255) << (i * 8);
179 for (cid = 0, i = 0; i < 4; i++)
180 cid |= (readl(tmp + size - 0x10 + 4 * i) & 255) << (i * 8);
182 if (cid == CORESIGHT_CID) {
183 /* set the base to the start of the last 4k block */
184 void __iomem *csbase = tmp + size - 4096;
186 dev->uci.devarch = readl(csbase + UCI_REG_DEVARCH_OFFSET);
187 dev->uci.devtype = readl(csbase + UCI_REG_DEVTYPE_OFFSET) & 0xff;
190 if (cid == AMBA_CID || cid == CORESIGHT_CID) {
201 amba_put_disable_pclk(dev);
203 dev_pm_domain_detach(&dev->dev, true);
208 static int amba_match(struct device *dev, struct device_driver *drv)
210 struct amba_device *pcdev = to_amba_device(dev);
211 struct amba_driver *pcdrv = to_amba_driver(drv);
213 mutex_lock(&pcdev->periphid_lock);
214 if (!pcdev->periphid) {
215 int ret = amba_read_periphid(pcdev);
218 * Returning any error other than -EPROBE_DEFER from bus match
219 * can cause driver registration failure. So, if there's a
220 * permanent failure in reading pid and cid, simply map it to
224 mutex_unlock(&pcdev->periphid_lock);
225 return -EPROBE_DEFER;
227 dev_set_uevent_suppress(dev, false);
228 kobject_uevent(&dev->kobj, KOBJ_ADD);
230 mutex_unlock(&pcdev->periphid_lock);
232 /* When driver_override is set, only bind to the matching driver */
233 if (pcdev->driver_override)
234 return !strcmp(pcdev->driver_override, drv->name);
236 return amba_lookup(pcdrv->id_table, pcdev) != NULL;
239 static int amba_uevent(const struct device *dev, struct kobj_uevent_env *env)
241 const struct amba_device *pcdev = to_amba_device(dev);
244 retval = add_uevent_var(env, "AMBA_ID=%08x", pcdev->periphid);
248 retval = add_uevent_var(env, "MODALIAS=amba:d%08X", pcdev->periphid);
252 static int of_amba_device_decode_irq(struct amba_device *dev)
254 struct device_node *node = dev->dev.of_node;
257 if (IS_ENABLED(CONFIG_OF_IRQ) && node) {
258 /* Decode the IRQs and address ranges */
259 for (i = 0; i < AMBA_NR_IRQS; i++) {
260 irq = of_irq_get(node, i);
262 if (irq == -EPROBE_DEFER)
275 * These are the device model conversion veneers; they convert the
276 * device model structures to our more specific structures.
278 static int amba_probe(struct device *dev)
280 struct amba_device *pcdev = to_amba_device(dev);
281 struct amba_driver *pcdrv = to_amba_driver(dev->driver);
282 const struct amba_id *id = amba_lookup(pcdrv->id_table, pcdev);
286 ret = of_amba_device_decode_irq(pcdev);
290 ret = of_clk_set_defaults(dev->of_node, false);
294 ret = dev_pm_domain_attach(dev, true);
298 ret = amba_get_enable_pclk(pcdev);
300 dev_pm_domain_detach(dev, true);
304 pm_runtime_get_noresume(dev);
305 pm_runtime_set_active(dev);
306 pm_runtime_enable(dev);
308 ret = pcdrv->probe(pcdev, id);
312 pm_runtime_disable(dev);
313 pm_runtime_set_suspended(dev);
314 pm_runtime_put_noidle(dev);
316 amba_put_disable_pclk(pcdev);
317 dev_pm_domain_detach(dev, true);
323 static void amba_remove(struct device *dev)
325 struct amba_device *pcdev = to_amba_device(dev);
326 struct amba_driver *drv = to_amba_driver(dev->driver);
328 pm_runtime_get_sync(dev);
331 pm_runtime_put_noidle(dev);
333 /* Undo the runtime PM settings in amba_probe() */
334 pm_runtime_disable(dev);
335 pm_runtime_set_suspended(dev);
336 pm_runtime_put_noidle(dev);
338 amba_put_disable_pclk(pcdev);
339 dev_pm_domain_detach(dev, true);
342 static void amba_shutdown(struct device *dev)
344 struct amba_driver *drv;
349 drv = to_amba_driver(dev->driver);
351 drv->shutdown(to_amba_device(dev));
354 static int amba_dma_configure(struct device *dev)
356 struct amba_driver *drv = to_amba_driver(dev->driver);
357 enum dev_dma_attr attr;
361 ret = of_dma_configure(dev, dev->of_node, true);
362 } else if (has_acpi_companion(dev)) {
363 attr = acpi_get_dma_attr(to_acpi_device_node(dev->fwnode));
364 ret = acpi_dma_configure(dev, attr);
367 if (!ret && !drv->driver_managed_dma) {
368 ret = iommu_device_use_default_domain(dev);
370 arch_teardown_dma_ops(dev);
376 static void amba_dma_cleanup(struct device *dev)
378 struct amba_driver *drv = to_amba_driver(dev->driver);
380 if (!drv->driver_managed_dma)
381 iommu_device_unuse_default_domain(dev);
386 * Hooks to provide runtime PM of the pclk (bus clock). It is safe to
387 * enable/disable the bus clock at runtime PM suspend/resume as this
388 * does not result in loss of context.
390 static int amba_pm_runtime_suspend(struct device *dev)
392 struct amba_device *pcdev = to_amba_device(dev);
393 int ret = pm_generic_runtime_suspend(dev);
395 if (ret == 0 && dev->driver) {
396 if (pm_runtime_is_irq_safe(dev))
397 clk_disable(pcdev->pclk);
399 clk_disable_unprepare(pcdev->pclk);
405 static int amba_pm_runtime_resume(struct device *dev)
407 struct amba_device *pcdev = to_amba_device(dev);
411 if (pm_runtime_is_irq_safe(dev))
412 ret = clk_enable(pcdev->pclk);
414 ret = clk_prepare_enable(pcdev->pclk);
415 /* Failure is probably fatal to the system, but... */
420 return pm_generic_runtime_resume(dev);
422 #endif /* CONFIG_PM */
424 static const struct dev_pm_ops amba_pm = {
426 amba_pm_runtime_suspend,
427 amba_pm_runtime_resume,
433 * Primecells are part of the Advanced Microcontroller Bus Architecture,
434 * so we call the bus "amba".
435 * DMA configuration for platform and AMBA bus is same. So here we reuse
436 * platform's DMA config routine.
438 struct bus_type amba_bustype = {
440 .dev_groups = amba_dev_groups,
442 .uevent = amba_uevent,
444 .remove = amba_remove,
445 .shutdown = amba_shutdown,
446 .dma_configure = amba_dma_configure,
447 .dma_cleanup = amba_dma_cleanup,
450 EXPORT_SYMBOL_GPL(amba_bustype);
452 static int __init amba_init(void)
454 return bus_register(&amba_bustype);
457 postcore_initcall(amba_init);
459 static int amba_proxy_probe(struct amba_device *adev,
460 const struct amba_id *id)
462 WARN(1, "Stub driver should never match any device.\n");
466 static const struct amba_id amba_stub_drv_ids[] = {
470 static struct amba_driver amba_proxy_drv = {
472 .name = "amba-proxy",
474 .probe = amba_proxy_probe,
475 .id_table = amba_stub_drv_ids,
478 static int __init amba_stub_drv_init(void)
480 if (!IS_ENABLED(CONFIG_MODULES))
484 * The amba_match() function will get called only if there is at least
485 * one amba driver registered. If all amba drivers are modules and are
486 * only loaded based on uevents, then we'll hit a chicken-and-egg
487 * situation where amba_match() is waiting on drivers and drivers are
488 * waiting on amba_match(). So, register a stub driver to make sure
489 * amba_match() is called even if no amba driver has been registered.
491 return amba_driver_register(&amba_proxy_drv);
493 late_initcall_sync(amba_stub_drv_init);
496 * amba_driver_register - register an AMBA device driver
497 * @drv: amba device driver structure
499 * Register an AMBA device driver with the Linux device model
500 * core. If devices pre-exist, the drivers probe function will
503 int amba_driver_register(struct amba_driver *drv)
508 drv->drv.bus = &amba_bustype;
510 return driver_register(&drv->drv);
512 EXPORT_SYMBOL(amba_driver_register);
515 * amba_driver_unregister - remove an AMBA device driver
516 * @drv: AMBA device driver structure to remove
518 * Unregister an AMBA device driver from the Linux device
519 * model. The device model will call the drivers remove function
520 * for each device the device driver is currently handling.
522 void amba_driver_unregister(struct amba_driver *drv)
524 driver_unregister(&drv->drv);
526 EXPORT_SYMBOL(amba_driver_unregister);
528 static void amba_device_release(struct device *dev)
530 struct amba_device *d = to_amba_device(dev);
532 fwnode_handle_put(dev_fwnode(&d->dev));
534 release_resource(&d->res);
535 mutex_destroy(&d->periphid_lock);
540 * amba_device_add - add a previously allocated AMBA device structure
541 * @dev: AMBA device allocated by amba_device_alloc
542 * @parent: resource parent for this devices resources
544 * Claim the resource, and read the device cell ID if not already
545 * initialized. Register the AMBA device with the Linux device
548 int amba_device_add(struct amba_device *dev, struct resource *parent)
552 fwnode_handle_get(dev_fwnode(&dev->dev));
554 ret = request_resource(parent, &dev->res);
558 /* If primecell ID isn't hard-coded, figure it out */
559 if (!dev->periphid) {
561 * AMBA device uevents require reading its pid and cid
562 * registers. To do this, the device must be on, clocked and
563 * out of reset. However in some cases those resources might
564 * not yet be available. If that's the case, we suppress the
565 * generation of uevents until we can read the pid and cid
566 * registers. See also amba_match().
568 if (amba_read_periphid(dev))
569 dev_set_uevent_suppress(&dev->dev, true);
572 ret = device_add(&dev->dev);
574 release_resource(&dev->res);
578 EXPORT_SYMBOL_GPL(amba_device_add);
580 static void amba_device_initialize(struct amba_device *dev, const char *name)
582 device_initialize(&dev->dev);
584 dev_set_name(&dev->dev, "%s", name);
585 dev->dev.release = amba_device_release;
586 dev->dev.bus = &amba_bustype;
587 dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
588 dev->dev.dma_parms = &dev->dma_parms;
589 dev->res.name = dev_name(&dev->dev);
590 mutex_init(&dev->periphid_lock);
594 * amba_device_alloc - allocate an AMBA device
595 * @name: sysfs name of the AMBA device
596 * @base: base of AMBA device
597 * @size: size of AMBA device
599 * Allocate and initialize an AMBA device structure. Returns %NULL
602 struct amba_device *amba_device_alloc(const char *name, resource_size_t base,
605 struct amba_device *dev;
607 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
609 amba_device_initialize(dev, name);
610 dev->res.start = base;
611 dev->res.end = base + size - 1;
612 dev->res.flags = IORESOURCE_MEM;
617 EXPORT_SYMBOL_GPL(amba_device_alloc);
620 * amba_device_register - register an AMBA device
621 * @dev: AMBA device to register
622 * @parent: parent memory resource
624 * Setup the AMBA device, reading the cell ID if present.
625 * Claim the resource, and register the AMBA device with
626 * the Linux device manager.
628 int amba_device_register(struct amba_device *dev, struct resource *parent)
630 amba_device_initialize(dev, dev->dev.init_name);
631 dev->dev.init_name = NULL;
633 return amba_device_add(dev, parent);
635 EXPORT_SYMBOL(amba_device_register);
638 * amba_device_put - put an AMBA device
639 * @dev: AMBA device to put
641 void amba_device_put(struct amba_device *dev)
643 put_device(&dev->dev);
645 EXPORT_SYMBOL_GPL(amba_device_put);
648 * amba_device_unregister - unregister an AMBA device
649 * @dev: AMBA device to remove
651 * Remove the specified AMBA device from the Linux device
652 * manager. All files associated with this object will be
653 * destroyed, and device drivers notified that the device has
654 * been removed. The AMBA device's resources including
655 * the amba_device structure will be freed once all
656 * references to it have been dropped.
658 void amba_device_unregister(struct amba_device *dev)
660 device_unregister(&dev->dev);
662 EXPORT_SYMBOL(amba_device_unregister);
665 * amba_request_regions - request all mem regions associated with device
666 * @dev: amba_device structure for device
667 * @name: name, or NULL to use driver name
669 int amba_request_regions(struct amba_device *dev, const char *name)
675 name = dev->dev.driver->name;
677 size = resource_size(&dev->res);
679 if (!request_mem_region(dev->res.start, size, name))
684 EXPORT_SYMBOL(amba_request_regions);
687 * amba_release_regions - release mem regions associated with device
688 * @dev: amba_device structure for device
690 * Release regions claimed by a successful call to amba_request_regions.
692 void amba_release_regions(struct amba_device *dev)
696 size = resource_size(&dev->res);
697 release_mem_region(dev->res.start, size);
699 EXPORT_SYMBOL(amba_release_regions);