bus.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 *  linux/arch/arm/common/amba.c
  4 *
  5 *  Copyright (C) 2003 Deep Blue Solutions Ltd, All Rights Reserved.
  6 */
  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>
 12#include <linux/io.h>
 13#include <linux/pm.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>
 28
 29#define to_amba_driver(d)	container_of_const(d, struct amba_driver, drv)
 30
 31/* called on periphid match and class 0x9 coresight device. */
 32static int
 33amba_cs_uci_id_match(const struct amba_id *table, struct amba_device *dev)
 34{
 35	int ret = 0;
 36	struct amba_cs_uci_id *uci;
 37
 38	uci = table->data;
 39
 40	/* no table data or zero mask - return match on periphid */
 41	if (!uci || (uci->devarch_mask == 0))
 42		return 1;
 43
 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);
 47	return ret;
 48}
 49
 50static const struct amba_id *
 51amba_lookup(const struct amba_id *table, struct amba_device *dev)
 52{
 53	while (table->mask) {
 54		if (((dev->periphid & table->mask) == table->id) &&
 55			((dev->cid != CORESIGHT_CID) ||
 56			 (amba_cs_uci_id_match(table, dev))))
 57			return table;
 58		table++;
 59	}
 60	return NULL;
 61}
 62
 63static int amba_get_enable_pclk(struct amba_device *pcdev)
 64{
 65	int ret;
 66
 67	pcdev->pclk = clk_get(&pcdev->dev, "apb_pclk");
 68	if (IS_ERR(pcdev->pclk))
 69		return PTR_ERR(pcdev->pclk);
 70
 71	ret = clk_prepare_enable(pcdev->pclk);
 72	if (ret)
 73		clk_put(pcdev->pclk);
 74
 75	return ret;
 76}
 77
 78static void amba_put_disable_pclk(struct amba_device *pcdev)
 79{
 80	clk_disable_unprepare(pcdev->pclk);
 81	clk_put(pcdev->pclk);
 82}
 83
 84
 85static ssize_t driver_override_show(struct device *_dev,
 86				    struct device_attribute *attr, char *buf)
 87{
 88	struct amba_device *dev = to_amba_device(_dev);
 89	ssize_t len;
 90
 91	device_lock(_dev);
 92	len = sprintf(buf, "%s\n", dev->driver_override);
 93	device_unlock(_dev);
 94	return len;
 95}
 96
 97static ssize_t driver_override_store(struct device *_dev,
 98				     struct device_attribute *attr,
 99				     const char *buf, size_t count)
100{
101	struct amba_device *dev = to_amba_device(_dev);
102	int ret;
103
104	ret = driver_set_override(_dev, &dev->driver_override, buf, count);
105	if (ret)
106		return ret;
107
108	return count;
109}
110static DEVICE_ATTR_RW(driver_override);
111
112#define amba_attr_func(name,fmt,arg...)					\
113static ssize_t name##_show(struct device *_dev,				\
114			   struct device_attribute *attr, char *buf)	\
115{									\
116	struct amba_device *dev = to_amba_device(_dev);			\
117	return sprintf(buf, fmt, arg);					\
118}									\
119static DEVICE_ATTR_RO(name)
120
121amba_attr_func(id, "%08x\n", dev->periphid);
122amba_attr_func(resource, "\t%016llx\t%016llx\t%016lx\n",
123	 (unsigned long long)dev->res.start, (unsigned long long)dev->res.end,
124	 dev->res.flags);
125
126static struct attribute *amba_dev_attrs[] = {
127	&dev_attr_id.attr,
128	&dev_attr_resource.attr,
129	&dev_attr_driver_override.attr,
130	NULL,
131};
132ATTRIBUTE_GROUPS(amba_dev);
133
134static int amba_read_periphid(struct amba_device *dev)
135{
136	struct reset_control *rstc;
137	u32 size, pid, cid;
138	void __iomem *tmp;
139	int i, ret;
140
141	ret = dev_pm_domain_attach(&dev->dev, PD_FLAG_ATTACH_POWER_ON);
142	if (ret) {
143		dev_dbg(&dev->dev, "can't get PM domain: %d\n", ret);
144		goto err_out;
145	}
146
147	ret = amba_get_enable_pclk(dev);
148	if (ret) {
149		dev_dbg(&dev->dev, "can't get pclk: %d\n", ret);
150		goto err_pm;
151	}
152
153	/*
154	 * Find reset control(s) of the amba bus and de-assert them.
155	 */
156	rstc = of_reset_control_array_get_optional_shared(dev->dev.of_node);
157	if (IS_ERR(rstc)) {
158		ret = PTR_ERR(rstc);
159		if (ret != -EPROBE_DEFER)
160			dev_err(&dev->dev, "can't get reset: %d\n", ret);
161		goto err_clk;
162	}
163	reset_control_deassert(rstc);
164	reset_control_put(rstc);
165
166	size = resource_size(&dev->res);
167	tmp = ioremap(dev->res.start, size);
168	if (!tmp) {
169		ret = -ENOMEM;
170		goto err_clk;
171	}
172
173	/*
174	 * Read pid and cid based on size of resource
175	 * they are located at end of region
176	 */
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);
181
182	if (cid == CORESIGHT_CID) {
183		/* set the base to the start of the last 4k block */
184		void __iomem *csbase = tmp + size - 4096;
185
186		dev->uci.devarch = readl(csbase + UCI_REG_DEVARCH_OFFSET);
187		dev->uci.devtype = readl(csbase + UCI_REG_DEVTYPE_OFFSET) & 0xff;
188	}
189
190	if (cid == AMBA_CID || cid == CORESIGHT_CID) {
191		dev->periphid = pid;
192		dev->cid = cid;
193	}
194
195	if (!dev->periphid)
196		ret = -ENODEV;
197
198	iounmap(tmp);
199
200err_clk:
201	amba_put_disable_pclk(dev);
202err_pm:
203	dev_pm_domain_detach(&dev->dev, true);
204err_out:
205	return ret;
206}
207
208static int amba_match(struct device *dev, const struct device_driver *drv)
209{
210	struct amba_device *pcdev = to_amba_device(dev);
211	const struct amba_driver *pcdrv = to_amba_driver(drv);
212
213	mutex_lock(&pcdev->periphid_lock);
214	if (!pcdev->periphid) {
215		int ret = amba_read_periphid(pcdev);
216
217		/*
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
221		 * -EPROBE_DEFER.
222		 */
223		if (ret) {
224			mutex_unlock(&pcdev->periphid_lock);
225			return -EPROBE_DEFER;
226		}
227		dev_set_uevent_suppress(dev, false);
228		kobject_uevent(&dev->kobj, KOBJ_ADD);
229	}
230	mutex_unlock(&pcdev->periphid_lock);
231
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);
235
236	return amba_lookup(pcdrv->id_table, pcdev) != NULL;
237}
238
239static int amba_uevent(const struct device *dev, struct kobj_uevent_env *env)
240{
241	const struct amba_device *pcdev = to_amba_device(dev);
242	int retval = 0;
243
244	retval = add_uevent_var(env, "AMBA_ID=%08x", pcdev->periphid);
245	if (retval)
246		return retval;
247
248	retval = add_uevent_var(env, "MODALIAS=amba:d%08X", pcdev->periphid);
249	return retval;
250}
251
252static int of_amba_device_decode_irq(struct amba_device *dev)
253{
254	struct device_node *node = dev->dev.of_node;
255	int i, irq = 0;
256
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);
261			if (irq < 0) {
262				if (irq == -EPROBE_DEFER)
263					return irq;
264				irq = 0;
265			}
266
267			dev->irq[i] = irq;
268		}
269	}
270
271	return 0;
272}
273
274/*
275 * These are the device model conversion veneers; they convert the
276 * device model structures to our more specific structures.
277 */
278static int amba_probe(struct device *dev)
279{
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);
283	int ret;
284
285	do {
286		ret = of_amba_device_decode_irq(pcdev);
287		if (ret)
288			break;
289
290		ret = of_clk_set_defaults(dev->of_node, false);
291		if (ret < 0)
292			break;
293
294		ret = dev_pm_domain_attach(dev, PD_FLAG_ATTACH_POWER_ON |
295						PD_FLAG_DETACH_POWER_OFF);
296		if (ret)
297			break;
298
299		ret = amba_get_enable_pclk(pcdev);
300		if (ret)
301			break;
302
303		pm_runtime_get_noresume(dev);
304		pm_runtime_set_active(dev);
305		pm_runtime_enable(dev);
306
307		ret = pcdrv->probe(pcdev, id);
308		if (ret == 0)
309			break;
310
311		pm_runtime_disable(dev);
312		pm_runtime_set_suspended(dev);
313		pm_runtime_put_noidle(dev);
314
315		amba_put_disable_pclk(pcdev);
316	} while (0);
317
318	return ret;
319}
320
321static void amba_remove(struct device *dev)
322{
323	struct amba_device *pcdev = to_amba_device(dev);
324	struct amba_driver *drv = to_amba_driver(dev->driver);
325
326	pm_runtime_get_sync(dev);
327	if (drv->remove)
328		drv->remove(pcdev);
329	pm_runtime_put_noidle(dev);
330
331	/* Undo the runtime PM settings in amba_probe() */
332	pm_runtime_disable(dev);
333	pm_runtime_set_suspended(dev);
334	pm_runtime_put_noidle(dev);
335
336	amba_put_disable_pclk(pcdev);
337}
338
339static void amba_shutdown(struct device *dev)
340{
341	struct amba_driver *drv;
342
343	if (!dev->driver)
344		return;
345
346	drv = to_amba_driver(dev->driver);
347	if (drv->shutdown)
348		drv->shutdown(to_amba_device(dev));
349}
350
351static int amba_dma_configure(struct device *dev)
352{
353	struct amba_driver *drv = to_amba_driver(dev->driver);
354	enum dev_dma_attr attr;
355	int ret = 0;
356
357	if (dev->of_node) {
358		ret = of_dma_configure(dev, dev->of_node, true);
359	} else if (has_acpi_companion(dev)) {
360		attr = acpi_get_dma_attr(to_acpi_device_node(dev->fwnode));
361		ret = acpi_dma_configure(dev, attr);
362	}
363
364	/* @drv may not be valid when we're called from the IOMMU layer */
365	if (!ret && dev->driver && !drv->driver_managed_dma) {
366		ret = iommu_device_use_default_domain(dev);
367		if (ret)
368			arch_teardown_dma_ops(dev);
369	}
370
371	return ret;
372}
373
374static void amba_dma_cleanup(struct device *dev)
375{
376	struct amba_driver *drv = to_amba_driver(dev->driver);
377
378	if (!drv->driver_managed_dma)
379		iommu_device_unuse_default_domain(dev);
380}
381
382#ifdef CONFIG_PM
383/*
384 * Hooks to provide runtime PM of the pclk (bus clock).  It is safe to
385 * enable/disable the bus clock at runtime PM suspend/resume as this
386 * does not result in loss of context.
387 */
388static int amba_pm_runtime_suspend(struct device *dev)
389{
390	struct amba_device *pcdev = to_amba_device(dev);
391	int ret = pm_generic_runtime_suspend(dev);
392
393	if (ret == 0 && dev->driver) {
394		if (pm_runtime_is_irq_safe(dev))
395			clk_disable(pcdev->pclk);
396		else
397			clk_disable_unprepare(pcdev->pclk);
398	}
399
400	return ret;
401}
402
403static int amba_pm_runtime_resume(struct device *dev)
404{
405	struct amba_device *pcdev = to_amba_device(dev);
406	int ret;
407
408	if (dev->driver) {
409		if (pm_runtime_is_irq_safe(dev))
410			ret = clk_enable(pcdev->pclk);
411		else
412			ret = clk_prepare_enable(pcdev->pclk);
413		/* Failure is probably fatal to the system, but... */
414		if (ret)
415			return ret;
416	}
417
418	return pm_generic_runtime_resume(dev);
419}
420#endif /* CONFIG_PM */
421
422static const struct dev_pm_ops amba_pm = {
423	SET_RUNTIME_PM_OPS(
424		amba_pm_runtime_suspend,
425		amba_pm_runtime_resume,
426		NULL
427	)
428};
429
430/*
431 * Primecells are part of the Advanced Microcontroller Bus Architecture,
432 * so we call the bus "amba".
433 * DMA configuration for platform and AMBA bus is same. So here we reuse
434 * platform's DMA config routine.
435 */
436const struct bus_type amba_bustype = {
437	.name		= "amba",
438	.dev_groups	= amba_dev_groups,
439	.match		= amba_match,
440	.uevent		= amba_uevent,
441	.probe		= amba_probe,
442	.remove		= amba_remove,
443	.shutdown	= amba_shutdown,
444	.dma_configure	= amba_dma_configure,
445	.dma_cleanup	= amba_dma_cleanup,
446	.pm		= &amba_pm,
447};
448EXPORT_SYMBOL_GPL(amba_bustype);
449
450bool dev_is_amba(const struct device *dev)
451{
452	return dev->bus == &amba_bustype;
453}
454EXPORT_SYMBOL_GPL(dev_is_amba);
455
456static int __init amba_init(void)
457{
458	return bus_register(&amba_bustype);
459}
460
461postcore_initcall(amba_init);
462
463static int amba_proxy_probe(struct amba_device *adev,
464			    const struct amba_id *id)
465{
466	WARN(1, "Stub driver should never match any device.\n");
467	return -ENODEV;
468}
469
470static const struct amba_id amba_stub_drv_ids[] = {
471	{ 0, 0 },
472};
473
474static struct amba_driver amba_proxy_drv = {
475	.drv = {
476		.name = "amba-proxy",
477	},
478	.probe = amba_proxy_probe,
479	.id_table = amba_stub_drv_ids,
480};
481
482static int __init amba_stub_drv_init(void)
483{
484	if (!IS_ENABLED(CONFIG_MODULES))
485		return 0;
486
487	/*
488	 * The amba_match() function will get called only if there is at least
489	 * one amba driver registered. If all amba drivers are modules and are
490	 * only loaded based on uevents, then we'll hit a chicken-and-egg
491	 * situation where amba_match() is waiting on drivers and drivers are
492	 * waiting on amba_match(). So, register a stub driver to make sure
493	 * amba_match() is called even if no amba driver has been registered.
494	 */
495	return __amba_driver_register(&amba_proxy_drv, NULL);
496}
497late_initcall_sync(amba_stub_drv_init);
498
499/**
500 *	__amba_driver_register - register an AMBA device driver
501 *	@drv: amba device driver structure
502 *	@owner: owning module/driver
503 *
504 *	Register an AMBA device driver with the Linux device model
505 *	core.  If devices pre-exist, the drivers probe function will
506 *	be called.
507 */
508int __amba_driver_register(struct amba_driver *drv,
509			   struct module *owner)
510{
511	if (!drv->probe)
512		return -EINVAL;
513
514	drv->drv.owner = owner;
515	drv->drv.bus = &amba_bustype;
516
517	return driver_register(&drv->drv);
518}
519EXPORT_SYMBOL(__amba_driver_register);
520
521/**
522 *	amba_driver_unregister - remove an AMBA device driver
523 *	@drv: AMBA device driver structure to remove
524 *
525 *	Unregister an AMBA device driver from the Linux device
526 *	model.  The device model will call the drivers remove function
527 *	for each device the device driver is currently handling.
528 */
529void amba_driver_unregister(struct amba_driver *drv)
530{
531	driver_unregister(&drv->drv);
532}
533EXPORT_SYMBOL(amba_driver_unregister);
534
535static void amba_device_release(struct device *dev)
536{
537	struct amba_device *d = to_amba_device(dev);
538
539	fwnode_handle_put(dev_fwnode(&d->dev));
540	if (d->res.parent)
541		release_resource(&d->res);
542	mutex_destroy(&d->periphid_lock);
543	kfree(d);
544}
545
546/**
547 *	amba_device_add - add a previously allocated AMBA device structure
548 *	@dev: AMBA device allocated by amba_device_alloc
549 *	@parent: resource parent for this devices resources
550 *
551 *	Claim the resource, and read the device cell ID if not already
552 *	initialized.  Register the AMBA device with the Linux device
553 *	manager.
554 */
555int amba_device_add(struct amba_device *dev, struct resource *parent)
556{
557	int ret;
558
559	fwnode_handle_get(dev_fwnode(&dev->dev));
560
561	ret = request_resource(parent, &dev->res);
562	if (ret)
563		return ret;
564
565	/* If primecell ID isn't hard-coded, figure it out */
566	if (!dev->periphid) {
567		/*
568		 * AMBA device uevents require reading its pid and cid
569		 * registers.  To do this, the device must be on, clocked and
570		 * out of reset.  However in some cases those resources might
571		 * not yet be available.  If that's the case, we suppress the
572		 * generation of uevents until we can read the pid and cid
573		 * registers.  See also amba_match().
574		 */
575		if (amba_read_periphid(dev))
576			dev_set_uevent_suppress(&dev->dev, true);
577	}
578
579	ret = device_add(&dev->dev);
580	if (ret)
581		release_resource(&dev->res);
582
583	return ret;
584}
585EXPORT_SYMBOL_GPL(amba_device_add);
586
587static void amba_device_initialize(struct amba_device *dev, const char *name)
588{
589	device_initialize(&dev->dev);
590	if (name)
591		dev_set_name(&dev->dev, "%s", name);
592	dev->dev.release = amba_device_release;
593	dev->dev.bus = &amba_bustype;
594	dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
595	dev->dev.dma_parms = &dev->dma_parms;
596	dev->res.name = dev_name(&dev->dev);
597	mutex_init(&dev->periphid_lock);
598}
599
600/**
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
605 *
606 *	Allocate and initialize an AMBA device structure.  Returns %NULL
607 *	on failure.
608 */
609struct amba_device *amba_device_alloc(const char *name, resource_size_t base,
610	size_t size)
611{
612	struct amba_device *dev;
613
614	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
615	if (dev) {
616		amba_device_initialize(dev, name);
617		dev->res.start = base;
618		dev->res.end = base + size - 1;
619		dev->res.flags = IORESOURCE_MEM;
620	}
621
622	return dev;
623}
624EXPORT_SYMBOL_GPL(amba_device_alloc);
625
626/**
627 *	amba_device_register - register an AMBA device
628 *	@dev: AMBA device to register
629 *	@parent: parent memory resource
630 *
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.
634 */
635int amba_device_register(struct amba_device *dev, struct resource *parent)
636{
637	amba_device_initialize(dev, dev->dev.init_name);
638	dev->dev.init_name = NULL;
639
640	return amba_device_add(dev, parent);
641}
642EXPORT_SYMBOL(amba_device_register);
643
644/**
645 *	amba_device_put - put an AMBA device
646 *	@dev: AMBA device to put
647 */
648void amba_device_put(struct amba_device *dev)
649{
650	put_device(&dev->dev);
651}
652EXPORT_SYMBOL_GPL(amba_device_put);
653
654/**
655 *	amba_device_unregister - unregister an AMBA device
656 *	@dev: AMBA device to remove
657 *
658 *	Remove the specified AMBA device from the Linux device
659 *	manager.  All files associated with this object will be
660 *	destroyed, and device drivers notified that the device has
661 *	been removed.  The AMBA device's resources including
662 *	the amba_device structure will be freed once all
663 *	references to it have been dropped.
664 */
665void amba_device_unregister(struct amba_device *dev)
666{
667	device_unregister(&dev->dev);
668}
669EXPORT_SYMBOL(amba_device_unregister);
670
671/**
672 *	amba_request_regions - request all mem regions associated with device
673 *	@dev: amba_device structure for device
674 *	@name: name, or NULL to use driver name
675 */
676int amba_request_regions(struct amba_device *dev, const char *name)
677{
678	int ret = 0;
679	u32 size;
680
681	if (!name)
682		name = dev->dev.driver->name;
683
684	size = resource_size(&dev->res);
685
686	if (!request_mem_region(dev->res.start, size, name))
687		ret = -EBUSY;
688
689	return ret;
690}
691EXPORT_SYMBOL(amba_request_regions);
692
693/**
694 *	amba_release_regions - release mem regions associated with device
695 *	@dev: amba_device structure for device
696 *
697 *	Release regions claimed by a successful call to amba_request_regions.
698 */
699void amba_release_regions(struct amba_device *dev)
700{
701	u32 size;
702
703	size = resource_size(&dev->res);
704	release_mem_region(dev->res.start, size);
705}
706EXPORT_SYMBOL(amba_release_regions);