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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
85#define amba_attr_func(name,fmt,arg...) \
86static ssize_t name##_show(struct device *_dev, \
87 struct device_attribute *attr, char *buf) \
88{ \
89 struct amba_device *dev = to_amba_device(_dev); \
90 return sprintf(buf, fmt, arg); \
91} \
92static DEVICE_ATTR_RO(name)
93
94amba_attr_func(id, "%08x\n", dev->periphid);
95amba_attr_func(resource, "\t%016llx\t%016llx\t%016lx\n",
96 (unsigned long long)dev->res.start, (unsigned long long)dev->res.end,
97 dev->res.flags);
98
99static struct attribute *amba_dev_attrs[] = {
100 &dev_attr_id.attr,
101 &dev_attr_resource.attr,
102 NULL,
103};
104ATTRIBUTE_GROUPS(amba_dev);
105
106static int amba_read_periphid(struct amba_device *dev)
107{
108 struct reset_control *rstc;
109 u32 size, pid, cid;
110 void __iomem *tmp;
111 int i, ret;
112
113 ret = dev_pm_domain_attach(&dev->dev, PD_FLAG_ATTACH_POWER_ON);
114 if (ret) {
115 dev_dbg(&dev->dev, "can't get PM domain: %d\n", ret);
116 goto err_out;
117 }
118
119 ret = amba_get_enable_pclk(dev);
120 if (ret) {
121 dev_dbg(&dev->dev, "can't get pclk: %d\n", ret);
122 goto err_pm;
123 }
124
125 /*
126 * Find reset control(s) of the amba bus and de-assert them.
127 */
128 rstc = of_reset_control_array_get_optional_shared(dev->dev.of_node);
129 if (IS_ERR(rstc)) {
130 ret = PTR_ERR(rstc);
131 if (ret != -EPROBE_DEFER)
132 dev_err(&dev->dev, "can't get reset: %d\n", ret);
133 goto err_clk;
134 }
135 reset_control_deassert(rstc);
136 reset_control_put(rstc);
137
138 size = resource_size(&dev->res);
139 tmp = ioremap(dev->res.start, size);
140 if (!tmp) {
141 ret = -ENOMEM;
142 goto err_clk;
143 }
144
145 /*
146 * Read pid and cid based on size of resource
147 * they are located at end of region
148 */
149 for (pid = 0, i = 0; i < 4; i++)
150 pid |= (readl(tmp + size - 0x20 + 4 * i) & 255) << (i * 8);
151 for (cid = 0, i = 0; i < 4; i++)
152 cid |= (readl(tmp + size - 0x10 + 4 * i) & 255) << (i * 8);
153
154 if (cid == CORESIGHT_CID) {
155 /* set the base to the start of the last 4k block */
156 void __iomem *csbase = tmp + size - 4096;
157
158 dev->uci.devarch = readl(csbase + UCI_REG_DEVARCH_OFFSET);
159 dev->uci.devtype = readl(csbase + UCI_REG_DEVTYPE_OFFSET) & 0xff;
160 }
161
162 if (cid == AMBA_CID || cid == CORESIGHT_CID) {
163 dev->periphid = pid;
164 dev->cid = cid;
165 }
166
167 if (!dev->periphid)
168 ret = -ENODEV;
169
170 iounmap(tmp);
171
172err_clk:
173 amba_put_disable_pclk(dev);
174err_pm:
175 dev_pm_domain_detach(&dev->dev, true);
176err_out:
177 return ret;
178}
179
180static int amba_match(struct device *dev, const struct device_driver *drv)
181{
182 struct amba_device *pcdev = to_amba_device(dev);
183 const struct amba_driver *pcdrv = to_amba_driver(drv);
184 int ret;
185
186 mutex_lock(&pcdev->periphid_lock);
187 if (!pcdev->periphid) {
188 ret = amba_read_periphid(pcdev);
189
190 /*
191 * Returning any error other than -EPROBE_DEFER from bus match
192 * can cause driver registration failure. So, if there's a
193 * permanent failure in reading pid and cid, simply map it to
194 * -EPROBE_DEFER.
195 */
196 if (ret) {
197 mutex_unlock(&pcdev->periphid_lock);
198 return -EPROBE_DEFER;
199 }
200 dev_set_uevent_suppress(dev, false);
201 kobject_uevent(&dev->kobj, KOBJ_ADD);
202 }
203 mutex_unlock(&pcdev->periphid_lock);
204
205 /* When driver_override is set, only bind to the matching driver */
206 ret = device_match_driver_override(dev, drv);
207 if (ret >= 0)
208 return ret;
209
210 return amba_lookup(pcdrv->id_table, pcdev) != NULL;
211}
212
213static int amba_uevent(const struct device *dev, struct kobj_uevent_env *env)
214{
215 const struct amba_device *pcdev = to_amba_device(dev);
216 int retval = 0;
217
218 retval = add_uevent_var(env, "AMBA_ID=%08x", pcdev->periphid);
219 if (retval)
220 return retval;
221
222 retval = add_uevent_var(env, "MODALIAS=amba:d%08X", pcdev->periphid);
223 return retval;
224}
225
226static int of_amba_device_decode_irq(struct amba_device *dev)
227{
228 struct device_node *node = dev->dev.of_node;
229 int i, irq = 0;
230
231 if (IS_ENABLED(CONFIG_OF_IRQ) && node) {
232 /* Decode the IRQs and address ranges */
233 for (i = 0; i < AMBA_NR_IRQS; i++) {
234 irq = of_irq_get(node, i);
235 if (irq < 0) {
236 if (irq == -EPROBE_DEFER)
237 return irq;
238 irq = 0;
239 }
240
241 dev->irq[i] = irq;
242 }
243 }
244
245 return 0;
246}
247
248/*
249 * These are the device model conversion veneers; they convert the
250 * device model structures to our more specific structures.
251 */
252static int amba_probe(struct device *dev)
253{
254 struct amba_device *pcdev = to_amba_device(dev);
255 struct amba_driver *pcdrv = to_amba_driver(dev->driver);
256 const struct amba_id *id = amba_lookup(pcdrv->id_table, pcdev);
257 int ret;
258
259 do {
260 ret = of_amba_device_decode_irq(pcdev);
261 if (ret)
262 break;
263
264 ret = of_clk_set_defaults(dev->of_node, false);
265 if (ret < 0)
266 break;
267
268 ret = dev_pm_domain_attach(dev, PD_FLAG_ATTACH_POWER_ON |
269 PD_FLAG_DETACH_POWER_OFF);
270 if (ret)
271 break;
272
273 ret = amba_get_enable_pclk(pcdev);
274 if (ret)
275 break;
276
277 pm_runtime_get_noresume(dev);
278 pm_runtime_set_active(dev);
279 pm_runtime_enable(dev);
280
281 ret = pcdrv->probe(pcdev, id);
282 if (ret == 0)
283 break;
284
285 pm_runtime_disable(dev);
286 pm_runtime_set_suspended(dev);
287 pm_runtime_put_noidle(dev);
288
289 amba_put_disable_pclk(pcdev);
290 } while (0);
291
292 return ret;
293}
294
295static void amba_remove(struct device *dev)
296{
297 struct amba_device *pcdev = to_amba_device(dev);
298 struct amba_driver *drv = to_amba_driver(dev->driver);
299
300 pm_runtime_get_sync(dev);
301 if (drv->remove)
302 drv->remove(pcdev);
303 pm_runtime_put_noidle(dev);
304
305 /* Undo the runtime PM settings in amba_probe() */
306 pm_runtime_disable(dev);
307 pm_runtime_set_suspended(dev);
308 pm_runtime_put_noidle(dev);
309
310 amba_put_disable_pclk(pcdev);
311}
312
313static void amba_shutdown(struct device *dev)
314{
315 struct amba_driver *drv;
316
317 if (!dev->driver)
318 return;
319
320 drv = to_amba_driver(dev->driver);
321 if (drv->shutdown)
322 drv->shutdown(to_amba_device(dev));
323}
324
325static int amba_dma_configure(struct device *dev)
326{
327 struct amba_driver *drv = to_amba_driver(dev->driver);
328 enum dev_dma_attr attr;
329 int ret = 0;
330
331 if (dev->of_node) {
332 ret = of_dma_configure(dev, dev->of_node, true);
333 } else if (has_acpi_companion(dev)) {
334 attr = acpi_get_dma_attr(to_acpi_device_node(dev->fwnode));
335 ret = acpi_dma_configure(dev, attr);
336 }
337
338 /* @drv may not be valid when we're called from the IOMMU layer */
339 if (!ret && dev->driver && !drv->driver_managed_dma) {
340 ret = iommu_device_use_default_domain(dev);
341 if (ret)
342 arch_teardown_dma_ops(dev);
343 }
344
345 return ret;
346}
347
348static void amba_dma_cleanup(struct device *dev)
349{
350 struct amba_driver *drv = to_amba_driver(dev->driver);
351
352 if (!drv->driver_managed_dma)
353 iommu_device_unuse_default_domain(dev);
354}
355
356#ifdef CONFIG_PM
357/*
358 * Hooks to provide runtime PM of the pclk (bus clock). It is safe to
359 * enable/disable the bus clock at runtime PM suspend/resume as this
360 * does not result in loss of context.
361 */
362static int amba_pm_runtime_suspend(struct device *dev)
363{
364 struct amba_device *pcdev = to_amba_device(dev);
365 int ret = pm_generic_runtime_suspend(dev);
366
367 if (ret == 0 && dev->driver) {
368 if (pm_runtime_is_irq_safe(dev))
369 clk_disable(pcdev->pclk);
370 else
371 clk_disable_unprepare(pcdev->pclk);
372 }
373
374 return ret;
375}
376
377static int amba_pm_runtime_resume(struct device *dev)
378{
379 struct amba_device *pcdev = to_amba_device(dev);
380 int ret;
381
382 if (dev->driver) {
383 if (pm_runtime_is_irq_safe(dev))
384 ret = clk_enable(pcdev->pclk);
385 else
386 ret = clk_prepare_enable(pcdev->pclk);
387 /* Failure is probably fatal to the system, but... */
388 if (ret)
389 return ret;
390 }
391
392 return pm_generic_runtime_resume(dev);
393}
394#endif /* CONFIG_PM */
395
396static const struct dev_pm_ops amba_pm = {
397 SET_RUNTIME_PM_OPS(
398 amba_pm_runtime_suspend,
399 amba_pm_runtime_resume,
400 NULL
401 )
402};
403
404/*
405 * Primecells are part of the Advanced Microcontroller Bus Architecture,
406 * so we call the bus "amba".
407 * DMA configuration for platform and AMBA bus is same. So here we reuse
408 * platform's DMA config routine.
409 */
410const struct bus_type amba_bustype = {
411 .name = "amba",
412 .dev_groups = amba_dev_groups,
413 .driver_override = true,
414 .match = amba_match,
415 .uevent = amba_uevent,
416 .probe = amba_probe,
417 .remove = amba_remove,
418 .shutdown = amba_shutdown,
419 .dma_configure = amba_dma_configure,
420 .dma_cleanup = amba_dma_cleanup,
421 .pm = &amba_pm,
422};
423EXPORT_SYMBOL_GPL(amba_bustype);
424
425bool dev_is_amba(const struct device *dev)
426{
427 return dev->bus == &amba_bustype;
428}
429EXPORT_SYMBOL_GPL(dev_is_amba);
430
431static int __init amba_init(void)
432{
433 return bus_register(&amba_bustype);
434}
435
436postcore_initcall(amba_init);
437
438static int amba_proxy_probe(struct amba_device *adev,
439 const struct amba_id *id)
440{
441 WARN(1, "Stub driver should never match any device.\n");
442 return -ENODEV;
443}
444
445static const struct amba_id amba_stub_drv_ids[] = {
446 { 0, 0 },
447};
448
449static struct amba_driver amba_proxy_drv = {
450 .drv = {
451 .name = "amba-proxy",
452 },
453 .probe = amba_proxy_probe,
454 .id_table = amba_stub_drv_ids,
455};
456
457static int __init amba_stub_drv_init(void)
458{
459 if (!IS_ENABLED(CONFIG_MODULES))
460 return 0;
461
462 /*
463 * The amba_match() function will get called only if there is at least
464 * one amba driver registered. If all amba drivers are modules and are
465 * only loaded based on uevents, then we'll hit a chicken-and-egg
466 * situation where amba_match() is waiting on drivers and drivers are
467 * waiting on amba_match(). So, register a stub driver to make sure
468 * amba_match() is called even if no amba driver has been registered.
469 */
470 return __amba_driver_register(&amba_proxy_drv, NULL);
471}
472late_initcall_sync(amba_stub_drv_init);
473
474/**
475 * __amba_driver_register - register an AMBA device driver
476 * @drv: amba device driver structure
477 * @owner: owning module/driver
478 *
479 * Register an AMBA device driver with the Linux device model
480 * core. If devices pre-exist, the drivers probe function will
481 * be called.
482 */
483int __amba_driver_register(struct amba_driver *drv,
484 struct module *owner)
485{
486 if (!drv->probe)
487 return -EINVAL;
488
489 drv->drv.owner = owner;
490 drv->drv.bus = &amba_bustype;
491
492 return driver_register(&drv->drv);
493}
494EXPORT_SYMBOL(__amba_driver_register);
495
496/**
497 * amba_driver_unregister - remove an AMBA device driver
498 * @drv: AMBA device driver structure to remove
499 *
500 * Unregister an AMBA device driver from the Linux device
501 * model. The device model will call the drivers remove function
502 * for each device the device driver is currently handling.
503 */
504void amba_driver_unregister(struct amba_driver *drv)
505{
506 driver_unregister(&drv->drv);
507}
508EXPORT_SYMBOL(amba_driver_unregister);
509
510static void amba_device_release(struct device *dev)
511{
512 struct amba_device *d = to_amba_device(dev);
513
514 fwnode_handle_put(dev_fwnode(&d->dev));
515 if (d->res.parent)
516 release_resource(&d->res);
517 mutex_destroy(&d->periphid_lock);
518 kfree(d);
519}
520
521/**
522 * amba_device_add - add a previously allocated AMBA device structure
523 * @dev: AMBA device allocated by amba_device_alloc
524 * @parent: resource parent for this devices resources
525 *
526 * Claim the resource, and read the device cell ID if not already
527 * initialized. Register the AMBA device with the Linux device
528 * manager.
529 */
530int amba_device_add(struct amba_device *dev, struct resource *parent)
531{
532 int ret;
533
534 fwnode_handle_get(dev_fwnode(&dev->dev));
535
536 ret = request_resource(parent, &dev->res);
537 if (ret)
538 return ret;
539
540 /* If primecell ID isn't hard-coded, figure it out */
541 if (!dev->periphid) {
542 /*
543 * AMBA device uevents require reading its pid and cid
544 * registers. To do this, the device must be on, clocked and
545 * out of reset. However in some cases those resources might
546 * not yet be available. If that's the case, we suppress the
547 * generation of uevents until we can read the pid and cid
548 * registers. See also amba_match().
549 */
550 if (amba_read_periphid(dev))
551 dev_set_uevent_suppress(&dev->dev, true);
552 }
553
554 ret = device_add(&dev->dev);
555 if (ret)
556 release_resource(&dev->res);
557
558 return ret;
559}
560EXPORT_SYMBOL_GPL(amba_device_add);
561
562static void amba_device_initialize(struct amba_device *dev, const char *name)
563{
564 device_initialize(&dev->dev);
565 if (name)
566 dev_set_name(&dev->dev, "%s", name);
567 dev->dev.release = amba_device_release;
568 dev->dev.bus = &amba_bustype;
569 dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
570 dev->dev.dma_parms = &dev->dma_parms;
571 dev->res.name = dev_name(&dev->dev);
572 mutex_init(&dev->periphid_lock);
573}
574
575/**
576 * amba_device_alloc - allocate an AMBA device
577 * @name: sysfs name of the AMBA device
578 * @base: base of AMBA device
579 * @size: size of AMBA device
580 *
581 * Allocate and initialize an AMBA device structure. Returns %NULL
582 * on failure.
583 */
584struct amba_device *amba_device_alloc(const char *name, resource_size_t base,
585 size_t size)
586{
587 struct amba_device *dev;
588
589 dev = kzalloc_obj(*dev);
590 if (dev) {
591 amba_device_initialize(dev, name);
592 dev->res.start = base;
593 dev->res.end = base + size - 1;
594 dev->res.flags = IORESOURCE_MEM;
595 }
596
597 return dev;
598}
599EXPORT_SYMBOL_GPL(amba_device_alloc);
600
601/**
602 * amba_device_register - register an AMBA device
603 * @dev: AMBA device to register
604 * @parent: parent memory resource
605 *
606 * Setup the AMBA device, reading the cell ID if present.
607 * Claim the resource, and register the AMBA device with
608 * the Linux device manager.
609 */
610int amba_device_register(struct amba_device *dev, struct resource *parent)
611{
612 amba_device_initialize(dev, dev->dev.init_name);
613 dev->dev.init_name = NULL;
614
615 return amba_device_add(dev, parent);
616}
617EXPORT_SYMBOL(amba_device_register);
618
619/**
620 * amba_device_put - put an AMBA device
621 * @dev: AMBA device to put
622 */
623void amba_device_put(struct amba_device *dev)
624{
625 put_device(&dev->dev);
626}
627EXPORT_SYMBOL_GPL(amba_device_put);
628
629/**
630 * amba_device_unregister - unregister an AMBA device
631 * @dev: AMBA device to remove
632 *
633 * Remove the specified AMBA device from the Linux device
634 * manager. All files associated with this object will be
635 * destroyed, and device drivers notified that the device has
636 * been removed. The AMBA device's resources including
637 * the amba_device structure will be freed once all
638 * references to it have been dropped.
639 */
640void amba_device_unregister(struct amba_device *dev)
641{
642 device_unregister(&dev->dev);
643}
644EXPORT_SYMBOL(amba_device_unregister);
645
646/**
647 * amba_request_regions - request all mem regions associated with device
648 * @dev: amba_device structure for device
649 * @name: name, or NULL to use driver name
650 */
651int amba_request_regions(struct amba_device *dev, const char *name)
652{
653 int ret = 0;
654 u32 size;
655
656 if (!name)
657 name = dev->dev.driver->name;
658
659 size = resource_size(&dev->res);
660
661 if (!request_mem_region(dev->res.start, size, name))
662 ret = -EBUSY;
663
664 return ret;
665}
666EXPORT_SYMBOL(amba_request_regions);
667
668/**
669 * amba_release_regions - release mem regions associated with device
670 * @dev: amba_device structure for device
671 *
672 * Release regions claimed by a successful call to amba_request_regions.
673 */
674void amba_release_regions(struct amba_device *dev)
675{
676 u32 size;
677
678 size = resource_size(&dev->res);
679 release_mem_region(dev->res.start, size);
680}
681EXPORT_SYMBOL(amba_release_regions);