summaryrefslogtreecommitdiff
path: root/drivers/rpmsg/rpmsg_core.c
blob: e1d765a7372c82c6c2daeb3c0c0c5c072429a2b6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
/*
 * remote processor messaging bus
 *
 * Copyright (C) 2011 Texas Instruments, Inc.
 * Copyright (C) 2011 Google, Inc.
 *
 * Ohad Ben-Cohen <ohad@wizery.com>
 * Brian Swetland <swetland@google.com>
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#define pr_fmt(fmt) "%s: " fmt, __func__

#include <linux/kernel.h>
#include <linux/rpmsg.h>

#include "rpmsg_internal.h"

/**
 * rpmsg_create_ept() - create a new rpmsg_endpoint
 * @rpdev: rpmsg channel device
 * @cb: rx callback handler
 * @priv: private data for the driver's use
 * @chinfo: channel_info with the local rpmsg address to bind with @cb
 *
 * Every rpmsg address in the system is bound to an rx callback (so when
 * inbound messages arrive, they are dispatched by the rpmsg bus using the
 * appropriate callback handler) by means of an rpmsg_endpoint struct.
 *
 * This function allows drivers to create such an endpoint, and by that,
 * bind a callback, and possibly some private data too, to an rpmsg address
 * (either one that is known in advance, or one that will be dynamically
 * assigned for them).
 *
 * Simple rpmsg drivers need not call rpmsg_create_ept, because an endpoint
 * is already created for them when they are probed by the rpmsg bus
 * (using the rx callback provided when they registered to the rpmsg bus).
 *
 * So things should just work for simple drivers: they already have an
 * endpoint, their rx callback is bound to their rpmsg address, and when
 * relevant inbound messages arrive (i.e. messages which their dst address
 * equals to the src address of their rpmsg channel), the driver's handler
 * is invoked to process it.
 *
 * That said, more complicated drivers might do need to allocate
 * additional rpmsg addresses, and bind them to different rx callbacks.
 * To accomplish that, those drivers need to call this function.
 *
 * Drivers should provide their @rpdev channel (so the new endpoint would belong
 * to the same remote processor their channel belongs to), an rx callback
 * function, an optional private data (which is provided back when the
 * rx callback is invoked), and an address they want to bind with the
 * callback. If @addr is RPMSG_ADDR_ANY, then rpmsg_create_ept will
 * dynamically assign them an available rpmsg address (drivers should have
 * a very good reason why not to always use RPMSG_ADDR_ANY here).
 *
 * Returns a pointer to the endpoint on success, or NULL on error.
 */
struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_device *rpdev,
					rpmsg_rx_cb_t cb, void *priv,
					struct rpmsg_channel_info chinfo)
{
	return rpdev->ops->create_ept(rpdev, cb, priv, chinfo);
}
EXPORT_SYMBOL(rpmsg_create_ept);

/**
 * rpmsg_destroy_ept() - destroy an existing rpmsg endpoint
 * @ept: endpoing to destroy
 *
 * Should be used by drivers to destroy an rpmsg endpoint previously
 * created with rpmsg_create_ept().
 */
void rpmsg_destroy_ept(struct rpmsg_endpoint *ept)
{
	ept->ops->destroy_ept(ept);
}
EXPORT_SYMBOL(rpmsg_destroy_ept);

/**
 * rpmsg_send() - send a message across to the remote processor
 * @ept: the rpmsg endpoint
 * @data: payload of message
 * @len: length of payload
 *
 * This function sends @data of length @len on the @ept endpoint.
 * The message will be sent to the remote processor which the @ept
 * endpoint belongs to, using @ept's address and its associated rpmsg
 * device destination addresses.
 * In case there are no TX buffers available, the function will block until
 * one becomes available, or a timeout of 15 seconds elapses. When the latter
 * happens, -ERESTARTSYS is returned.
 *
 * Can only be called from process context (for now).
 *
 * Returns 0 on success and an appropriate error value on failure.
 */
int rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len)
{
	return ept->ops->send(ept, data, len);
}
EXPORT_SYMBOL(rpmsg_send);

/**
 * rpmsg_sendto() - send a message across to the remote processor, specify dst
 * @ept: the rpmsg endpoint
 * @data: payload of message
 * @len: length of payload
 * @dst: destination address
 *
 * This function sends @data of length @len to the remote @dst address.
 * The message will be sent to the remote processor which the @ept
 * endpoint belongs to, using @ept's address as source.
 * In case there are no TX buffers available, the function will block until
 * one becomes available, or a timeout of 15 seconds elapses. When the latter
 * happens, -ERESTARTSYS is returned.
 *
 * Can only be called from process context (for now).
 *
 * Returns 0 on success and an appropriate error value on failure.
 */
int rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst)
{
	return ept->ops->sendto(ept, data, len, dst);
}
EXPORT_SYMBOL(rpmsg_sendto);

/**
 * rpmsg_send_offchannel() - send a message using explicit src/dst addresses
 * @ept: the rpmsg endpoint
 * @src: source address
 * @dst: destination address
 * @data: payload of message
 * @len: length of payload
 *
 * This function sends @data of length @len to the remote @dst address,
 * and uses @src as the source address.
 * The message will be sent to the remote processor which the @ept
 * endpoint belongs to.
 * In case there are no TX buffers available, the function will block until
 * one becomes available, or a timeout of 15 seconds elapses. When the latter
 * happens, -ERESTARTSYS is returned.
 *
 * Can only be called from process context (for now).
 *
 * Returns 0 on success and an appropriate error value on failure.
 */
int rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
			  void *data, int len)
{
	return ept->ops->send_offchannel(ept, src, dst, data, len);
}
EXPORT_SYMBOL(rpmsg_send_offchannel);

/**
 * rpmsg_send() - send a message across to the remote processor
 * @ept: the rpmsg endpoint
 * @data: payload of message
 * @len: length of payload
 *
 * This function sends @data of length @len on the @ept endpoint.
 * The message will be sent to the remote processor which the @ept
 * endpoint belongs to, using @ept's address as source and its associated
 * rpdev's address as destination.
 * In case there are no TX buffers available, the function will immediately
 * return -ENOMEM without waiting until one becomes available.
 *
 * Can only be called from process context (for now).
 *
 * Returns 0 on success and an appropriate error value on failure.
 */
int rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len)
{
	return ept->ops->trysend(ept, data, len);
}
EXPORT_SYMBOL(rpmsg_trysend);

/**
 * rpmsg_sendto() - send a message across to the remote processor, specify dst
 * @ept: the rpmsg endpoint
 * @data: payload of message
 * @len: length of payload
 * @dst: destination address
 *
 * This function sends @data of length @len to the remote @dst address.
 * The message will be sent to the remote processor which the @ept
 * endpoint belongs to, using @ept's address as source.
 * In case there are no TX buffers available, the function will immediately
 * return -ENOMEM without waiting until one becomes available.
 *
 * Can only be called from process context (for now).
 *
 * Returns 0 on success and an appropriate error value on failure.
 */
int rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst)
{
	return ept->ops->trysendto(ept, data, len, dst);
}
EXPORT_SYMBOL(rpmsg_trysendto);

/**
 * rpmsg_send_offchannel() - send a message using explicit src/dst addresses
 * @ept: the rpmsg endpoint
 * @src: source address
 * @dst: destination address
 * @data: payload of message
 * @len: length of payload
 *
 * This function sends @data of length @len to the remote @dst address,
 * and uses @src as the source address.
 * The message will be sent to the remote processor which the @ept
 * endpoint belongs to.
 * In case there are no TX buffers available, the function will immediately
 * return -ENOMEM without waiting until one becomes available.
 *
 * Can only be called from process context (for now).
 *
 * Returns 0 on success and an appropriate error value on failure.
 */
int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
			     void *data, int len)
{
	return ept->ops->trysend_offchannel(ept, src, dst, data, len);
}
EXPORT_SYMBOL(rpmsg_trysend_offchannel);

/*
 * match an rpmsg channel with a channel info struct.
 * this is used to make sure we're not creating rpmsg devices for channels
 * that already exist.
 */
static int rpmsg_device_match(struct device *dev, void *data)
{
	struct rpmsg_channel_info *chinfo = data;
	struct rpmsg_device *rpdev = to_rpmsg_device(dev);

	if (chinfo->src != RPMSG_ADDR_ANY && chinfo->src != rpdev->src)
		return 0;

	if (chinfo->dst != RPMSG_ADDR_ANY && chinfo->dst != rpdev->dst)
		return 0;

	if (strncmp(chinfo->name, rpdev->id.name, RPMSG_NAME_SIZE))
		return 0;

	/* found a match ! */
	return 1;
}

struct device *rpmsg_find_device(struct device *parent,
				 struct rpmsg_channel_info *chinfo)
{
	return device_find_child(parent, chinfo, rpmsg_device_match);

}
EXPORT_SYMBOL(rpmsg_find_device);

/* sysfs show configuration fields */
#define rpmsg_show_attr(field, path, format_string)			\
static ssize_t								\
field##_show(struct device *dev,					\
			struct device_attribute *attr, char *buf)	\
{									\
	struct rpmsg_device *rpdev = to_rpmsg_device(dev);		\
									\
	return sprintf(buf, format_string, rpdev->path);		\
}

/* for more info, see Documentation/ABI/testing/sysfs-bus-rpmsg */
rpmsg_show_attr(name, id.name, "%s\n");
rpmsg_show_attr(src, src, "0x%x\n");
rpmsg_show_attr(dst, dst, "0x%x\n");
rpmsg_show_attr(announce, announce ? "true" : "false", "%s\n");

static ssize_t modalias_show(struct device *dev,
			     struct device_attribute *attr, char *buf)
{
	struct rpmsg_device *rpdev = to_rpmsg_device(dev);

	return sprintf(buf, RPMSG_DEVICE_MODALIAS_FMT "\n", rpdev->id.name);
}

static struct device_attribute rpmsg_dev_attrs[] = {
	__ATTR_RO(name),
	__ATTR_RO(modalias),
	__ATTR_RO(dst),
	__ATTR_RO(src),
	__ATTR_RO(announce),
	__ATTR_NULL
};

/* rpmsg devices and drivers are matched using the service name */
static inline int rpmsg_id_match(const struct rpmsg_device *rpdev,
				  const struct rpmsg_device_id *id)
{
	return strncmp(id->name, rpdev->id.name, RPMSG_NAME_SIZE) == 0;
}

/* match rpmsg channel and rpmsg driver */
static int rpmsg_dev_match(struct device *dev, struct device_driver *drv)
{
	struct rpmsg_device *rpdev = to_rpmsg_device(dev);
	struct rpmsg_driver *rpdrv = to_rpmsg_driver(drv);
	const struct rpmsg_device_id *ids = rpdrv->id_table;
	unsigned int i;

	if (ids)
		for (i = 0; ids[i].name[0]; i++)
			if (rpmsg_id_match(rpdev, &ids[i]))
				return 1;

	return of_driver_match_device(dev, drv);
}

static int rpmsg_uevent(struct device *dev, struct kobj_uevent_env *env)
{
	struct rpmsg_device *rpdev = to_rpmsg_device(dev);

	return add_uevent_var(env, "MODALIAS=" RPMSG_DEVICE_MODALIAS_FMT,
					rpdev->id.name);
}

/*
 * when an rpmsg driver is probed with a channel, we seamlessly create
 * it an endpoint, binding its rx callback to a unique local rpmsg
 * address.
 *
 * if we need to, we also announce about this channel to the remote
 * processor (needed in case the driver is exposing an rpmsg service).
 */
static int rpmsg_dev_probe(struct device *dev)
{
	struct rpmsg_device *rpdev = to_rpmsg_device(dev);
	struct rpmsg_driver *rpdrv = to_rpmsg_driver(rpdev->dev.driver);
	struct rpmsg_channel_info chinfo = {};
	struct rpmsg_endpoint *ept;
	int err;

	strncpy(chinfo.name, rpdev->id.name, RPMSG_NAME_SIZE);
	chinfo.src = rpdev->src;
	chinfo.dst = RPMSG_ADDR_ANY;

	ept = rpmsg_create_ept(rpdev, rpdrv->callback, NULL, chinfo);
	if (!ept) {
		dev_err(dev, "failed to create endpoint\n");
		err = -ENOMEM;
		goto out;
	}

	rpdev->ept = ept;
	rpdev->src = ept->addr;

	err = rpdrv->probe(rpdev);
	if (err) {
		dev_err(dev, "%s: failed: %d\n", __func__, err);
		rpmsg_destroy_ept(ept);
		goto out;
	}

	if (rpdev->ops->announce_create)
		err = rpdev->ops->announce_create(rpdev);
out:
	return err;
}

static int rpmsg_dev_remove(struct device *dev)
{
	struct rpmsg_device *rpdev = to_rpmsg_device(dev);
	struct rpmsg_driver *rpdrv = to_rpmsg_driver(rpdev->dev.driver);
	int err = 0;

	if (rpdev->ops->announce_destroy)
		err = rpdev->ops->announce_destroy(rpdev);

	rpdrv->remove(rpdev);

	rpmsg_destroy_ept(rpdev->ept);

	return err;
}

static struct bus_type rpmsg_bus = {
	.name		= "rpmsg",
	.match		= rpmsg_dev_match,
	.dev_attrs	= rpmsg_dev_attrs,
	.uevent		= rpmsg_uevent,
	.probe		= rpmsg_dev_probe,
	.remove		= rpmsg_dev_remove,
};

static void rpmsg_release_device(struct device *dev)
{
	struct rpmsg_device *rpdev = to_rpmsg_device(dev);

	kfree(rpdev);
}

int rpmsg_register_device(struct rpmsg_device *rpdev)
{
	struct device *dev = &rpdev->dev;
	int ret;

	dev_set_name(&rpdev->dev, "%s:%s",
		     dev_name(dev->parent), rpdev->id.name);

	rpdev->dev.bus = &rpmsg_bus;
	rpdev->dev.release = rpmsg_release_device;

	ret = device_register(&rpdev->dev);
	if (ret) {
		dev_err(dev, "device_register failed: %d\n", ret);
		put_device(&rpdev->dev);
	}

	return ret;
}
EXPORT_SYMBOL(rpmsg_register_device);

/*
 * find an existing channel using its name + address properties,
 * and destroy it
 */
int rpmsg_unregister_device(struct device *parent,
			    struct rpmsg_channel_info *chinfo)
{
	struct device *dev;

	dev = rpmsg_find_device(parent, chinfo);
	if (!dev)
		return -EINVAL;

	device_unregister(dev);

	put_device(dev);

	return 0;
}
EXPORT_SYMBOL(rpmsg_unregister_device);

/**
 * __register_rpmsg_driver() - register an rpmsg driver with the rpmsg bus
 * @rpdrv: pointer to a struct rpmsg_driver
 * @owner: owning module/driver
 *
 * Returns 0 on success, and an appropriate error value on failure.
 */
int __register_rpmsg_driver(struct rpmsg_driver *rpdrv, struct module *owner)
{
	rpdrv->drv.bus = &rpmsg_bus;
	rpdrv->drv.owner = owner;
	return driver_register(&rpdrv->drv);
}
EXPORT_SYMBOL(__register_rpmsg_driver);

/**
 * unregister_rpmsg_driver() - unregister an rpmsg driver from the rpmsg bus
 * @rpdrv: pointer to a struct rpmsg_driver
 *
 * Returns 0 on success, and an appropriate error value on failure.
 */
void unregister_rpmsg_driver(struct rpmsg_driver *rpdrv)
{
	driver_unregister(&rpdrv->drv);
}
EXPORT_SYMBOL(unregister_rpmsg_driver);


static int __init rpmsg_init(void)
{
	int ret;

	ret = bus_register(&rpmsg_bus);
	if (ret)
		pr_err("failed to register rpmsg bus: %d\n", ret);

	return ret;
}
postcore_initcall(rpmsg_init);

static void __exit rpmsg_fini(void)
{
	bus_unregister(&rpmsg_bus);
}
module_exit(rpmsg_fini);

MODULE_DESCRIPTION("remote processor messaging bus");
MODULE_LICENSE("GPL v2");