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(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, true);
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, struct device_driver *drv)
209{
210	struct amba_device *pcdev = to_amba_device(dev);
211	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, true);
295		if (ret)
296			break;
297
298		ret = amba_get_enable_pclk(pcdev);
299		if (ret) {
300			dev_pm_domain_detach(dev, true);
301			break;
302		}
303
304		pm_runtime_get_noresume(dev);
305		pm_runtime_set_active(dev);
306		pm_runtime_enable(dev);
307
308		ret = pcdrv->probe(pcdev, id);
309		if (ret == 0)
310			break;
311
312		pm_runtime_disable(dev);
313		pm_runtime_set_suspended(dev);
314		pm_runtime_put_noidle(dev);
315
316		amba_put_disable_pclk(pcdev);
317		dev_pm_domain_detach(dev, true);
318	} while (0);
319
320	return ret;
321}
322
323static void amba_remove(struct device *dev)
324{
325	struct amba_device *pcdev = to_amba_device(dev);
326	struct amba_driver *drv = to_amba_driver(dev->driver);
327
328	pm_runtime_get_sync(dev);
329	if (drv->remove)
330		drv->remove(pcdev);
331	pm_runtime_put_noidle(dev);
332
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);
337
338	amba_put_disable_pclk(pcdev);
339	dev_pm_domain_detach(dev, true);
340}
341
342static void amba_shutdown(struct device *dev)
343{
344	struct amba_driver *drv;
345
346	if (!dev->driver)
347		return;
348
349	drv = to_amba_driver(dev->driver);
350	if (drv->shutdown)
351		drv->shutdown(to_amba_device(dev));
352}
353
354static int amba_dma_configure(struct device *dev)
355{
356	struct amba_driver *drv = to_amba_driver(dev->driver);
357	enum dev_dma_attr attr;
358	int ret = 0;
359
360	if (dev->of_node) {
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);
365	}
366
367	if (!ret && !drv->driver_managed_dma) {
368		ret = iommu_device_use_default_domain(dev);
369		if (ret)
370			arch_teardown_dma_ops(dev);
371	}
372
373	return ret;
374}
375
376static void amba_dma_cleanup(struct device *dev)
377{
378	struct amba_driver *drv = to_amba_driver(dev->driver);
379
380	if (!drv->driver_managed_dma)
381		iommu_device_unuse_default_domain(dev);
382}
383
384#ifdef CONFIG_PM
385/*
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.
389 */
390static int amba_pm_runtime_suspend(struct device *dev)
391{
392	struct amba_device *pcdev = to_amba_device(dev);
393	int ret = pm_generic_runtime_suspend(dev);
394
395	if (ret == 0 && dev->driver) {
396		if (pm_runtime_is_irq_safe(dev))
397			clk_disable(pcdev->pclk);
398		else
399			clk_disable_unprepare(pcdev->pclk);
400	}
401
402	return ret;
403}
404
405static int amba_pm_runtime_resume(struct device *dev)
406{
407	struct amba_device *pcdev = to_amba_device(dev);
408	int ret;
409
410	if (dev->driver) {
411		if (pm_runtime_is_irq_safe(dev))
412			ret = clk_enable(pcdev->pclk);
413		else
414			ret = clk_prepare_enable(pcdev->pclk);
415		/* Failure is probably fatal to the system, but... */
416		if (ret)
417			return ret;
418	}
419
420	return pm_generic_runtime_resume(dev);
421}
422#endif /* CONFIG_PM */
423
424static const struct dev_pm_ops amba_pm = {
425	SET_RUNTIME_PM_OPS(
426		amba_pm_runtime_suspend,
427		amba_pm_runtime_resume,
428		NULL
429	)
430};
431
432/*
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.
437 */
438struct bus_type amba_bustype = {
439	.name		= "amba",
440	.dev_groups	= amba_dev_groups,
441	.match		= amba_match,
442	.uevent		= amba_uevent,
443	.probe		= amba_probe,
444	.remove		= amba_remove,
445	.shutdown	= amba_shutdown,
446	.dma_configure	= amba_dma_configure,
447	.dma_cleanup	= amba_dma_cleanup,
448	.pm		= &amba_pm,
449};
450EXPORT_SYMBOL_GPL(amba_bustype);
451
452static int __init amba_init(void)
453{
454	return bus_register(&amba_bustype);
455}
456
457postcore_initcall(amba_init);
458
459static int amba_proxy_probe(struct amba_device *adev,
460			    const struct amba_id *id)
461{
462	WARN(1, "Stub driver should never match any device.\n");
463	return -ENODEV;
464}
465
466static const struct amba_id amba_stub_drv_ids[] = {
467	{ 0, 0 },
468};
469
470static struct amba_driver amba_proxy_drv = {
471	.drv = {
472		.name = "amba-proxy",
473	},
474	.probe = amba_proxy_probe,
475	.id_table = amba_stub_drv_ids,
476};
477
478static int __init amba_stub_drv_init(void)
479{
480	if (!IS_ENABLED(CONFIG_MODULES))
481		return 0;
482
483	/*
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.
490	 */
491	return amba_driver_register(&amba_proxy_drv);
492}
493late_initcall_sync(amba_stub_drv_init);
494
495/**
496 *	amba_driver_register - register an AMBA device driver
497 *	@drv: amba device driver structure
498 *
499 *	Register an AMBA device driver with the Linux device model
500 *	core.  If devices pre-exist, the drivers probe function will
501 *	be called.
502 */
503int amba_driver_register(struct amba_driver *drv)
504{
505	if (!drv->probe)
506		return -EINVAL;
507
508	drv->drv.bus = &amba_bustype;
509
510	return driver_register(&drv->drv);
511}
512EXPORT_SYMBOL(amba_driver_register);
513
514/**
515 *	amba_driver_unregister - remove an AMBA device driver
516 *	@drv: AMBA device driver structure to remove
517 *
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.
521 */
522void amba_driver_unregister(struct amba_driver *drv)
523{
524	driver_unregister(&drv->drv);
525}
526EXPORT_SYMBOL(amba_driver_unregister);
527
528static void amba_device_release(struct device *dev)
529{
530	struct amba_device *d = to_amba_device(dev);
531
532	fwnode_handle_put(dev_fwnode(&d->dev));
533	if (d->res.parent)
534		release_resource(&d->res);
535	mutex_destroy(&d->periphid_lock);
536	kfree(d);
537}
538
539/**
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
543 *
544 *	Claim the resource, and read the device cell ID if not already
545 *	initialized.  Register the AMBA device with the Linux device
546 *	manager.
547 */
548int amba_device_add(struct amba_device *dev, struct resource *parent)
549{
550	int ret;
551
552	fwnode_handle_get(dev_fwnode(&dev->dev));
553
554	ret = request_resource(parent, &dev->res);
555	if (ret)
556		return ret;
557
558	/* If primecell ID isn't hard-coded, figure it out */
559	if (!dev->periphid) {
560		/*
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().
567		 */
568		if (amba_read_periphid(dev))
569			dev_set_uevent_suppress(&dev->dev, true);
570	}
571
572	ret = device_add(&dev->dev);
573	if (ret)
574		release_resource(&dev->res);
575
576	return ret;
577}
578EXPORT_SYMBOL_GPL(amba_device_add);
579
580static void amba_device_initialize(struct amba_device *dev, const char *name)
581{
582	device_initialize(&dev->dev);
583	if (name)
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);
591}
592
593/**
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
598 *
599 *	Allocate and initialize an AMBA device structure.  Returns %NULL
600 *	on failure.
601 */
602struct amba_device *amba_device_alloc(const char *name, resource_size_t base,
603	size_t size)
604{
605	struct amba_device *dev;
606
607	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
608	if (dev) {
609		amba_device_initialize(dev, name);
610		dev->res.start = base;
611		dev->res.end = base + size - 1;
612		dev->res.flags = IORESOURCE_MEM;
613	}
614
615	return dev;
616}
617EXPORT_SYMBOL_GPL(amba_device_alloc);
618
619/**
620 *	amba_device_register - register an AMBA device
621 *	@dev: AMBA device to register
622 *	@parent: parent memory resource
623 *
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.
627 */
628int amba_device_register(struct amba_device *dev, struct resource *parent)
629{
630	amba_device_initialize(dev, dev->dev.init_name);
631	dev->dev.init_name = NULL;
632
633	return amba_device_add(dev, parent);
634}
635EXPORT_SYMBOL(amba_device_register);
636
637/**
638 *	amba_device_put - put an AMBA device
639 *	@dev: AMBA device to put
640 */
641void amba_device_put(struct amba_device *dev)
642{
643	put_device(&dev->dev);
644}
645EXPORT_SYMBOL_GPL(amba_device_put);
646
647/**
648 *	amba_device_unregister - unregister an AMBA device
649 *	@dev: AMBA device to remove
650 *
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.
657 */
658void amba_device_unregister(struct amba_device *dev)
659{
660	device_unregister(&dev->dev);
661}
662EXPORT_SYMBOL(amba_device_unregister);
663
664/**
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
668 */
669int amba_request_regions(struct amba_device *dev, const char *name)
670{
671	int ret = 0;
672	u32 size;
673
674	if (!name)
675		name = dev->dev.driver->name;
676
677	size = resource_size(&dev->res);
678
679	if (!request_mem_region(dev->res.start, size, name))
680		ret = -EBUSY;
681
682	return ret;
683}
684EXPORT_SYMBOL(amba_request_regions);
685
686/**
687 *	amba_release_regions - release mem regions associated with device
688 *	@dev: amba_device structure for device
689 *
690 *	Release regions claimed by a successful call to amba_request_regions.
691 */
692void amba_release_regions(struct amba_device *dev)
693{
694	u32 size;
695
696	size = resource_size(&dev->res);
697	release_mem_region(dev->res.start, size);
698}
699EXPORT_SYMBOL(amba_release_regions);
700