Loading...
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Virtio-based remote processor messaging bus
4 *
5 * Copyright (C) 2011 Texas Instruments, Inc.
6 * Copyright (C) 2011 Google, Inc.
7 *
8 * Ohad Ben-Cohen <ohad@wizery.com>
9 * Brian Swetland <swetland@google.com>
10 */
11
12#define pr_fmt(fmt) "%s: " fmt, __func__
13
14#include <linux/dma-mapping.h>
15#include <linux/idr.h>
16#include <linux/jiffies.h>
17#include <linux/kernel.h>
18#include <linux/module.h>
19#include <linux/mutex.h>
20#include <linux/rpmsg.h>
21#include <linux/rpmsg/byteorder.h>
22#include <linux/rpmsg/ns.h>
23#include <linux/scatterlist.h>
24#include <linux/slab.h>
25#include <linux/sched.h>
26#include <linux/virtio.h>
27#include <linux/virtio_ids.h>
28#include <linux/virtio_config.h>
29#include <linux/wait.h>
30
31#include "rpmsg_internal.h"
32
33/**
34 * struct virtproc_info - virtual remote processor state
35 * @vdev: the virtio device
36 * @rvq: rx virtqueue
37 * @svq: tx virtqueue
38 * @rbufs: kernel address of rx buffers
39 * @sbufs: kernel address of tx buffers
40 * @num_bufs: total number of buffers for rx and tx
41 * @buf_size: size of one rx or tx buffer
42 * @last_sbuf: index of last tx buffer used
43 * @bufs_dma: dma base addr of the buffers
44 * @tx_lock: protects svq, sbufs and sleepers, to allow concurrent senders.
45 * sending a message might require waking up a dozing remote
46 * processor, which involves sleeping, hence the mutex.
47 * @endpoints: idr of local endpoints, allows fast retrieval
48 * @endpoints_lock: lock of the endpoints set
49 * @sendq: wait queue of sending contexts waiting for a tx buffers
50 * @sleepers: number of senders that are waiting for a tx buffer
51 *
52 * This structure stores the rpmsg state of a given virtio remote processor
53 * device (there might be several virtio proc devices for each physical
54 * remote processor).
55 */
56struct virtproc_info {
57 struct virtio_device *vdev;
58 struct virtqueue *rvq, *svq;
59 void *rbufs, *sbufs;
60 unsigned int num_bufs;
61 unsigned int buf_size;
62 int last_sbuf;
63 dma_addr_t bufs_dma;
64 struct mutex tx_lock;
65 struct idr endpoints;
66 struct mutex endpoints_lock;
67 wait_queue_head_t sendq;
68 atomic_t sleepers;
69};
70
71/* The feature bitmap for virtio rpmsg */
72#define VIRTIO_RPMSG_F_NS 0 /* RP supports name service notifications */
73
74/**
75 * struct rpmsg_hdr - common header for all rpmsg messages
76 * @src: source address
77 * @dst: destination address
78 * @reserved: reserved for future use
79 * @len: length of payload (in bytes)
80 * @flags: message flags
81 * @data: @len bytes of message payload data
82 *
83 * Every message sent(/received) on the rpmsg bus begins with this header.
84 */
85struct rpmsg_hdr {
86 __rpmsg32 src;
87 __rpmsg32 dst;
88 __rpmsg32 reserved;
89 __rpmsg16 len;
90 __rpmsg16 flags;
91 u8 data[];
92} __packed;
93
94
95/**
96 * struct virtio_rpmsg_channel - rpmsg channel descriptor
97 * @rpdev: the rpmsg channel device
98 * @vrp: the virtio remote processor device this channel belongs to
99 *
100 * This structure stores the channel that links the rpmsg device to the virtio
101 * remote processor device.
102 */
103struct virtio_rpmsg_channel {
104 struct rpmsg_device rpdev;
105
106 struct virtproc_info *vrp;
107};
108
109#define to_virtio_rpmsg_channel(_rpdev) \
110 container_of(_rpdev, struct virtio_rpmsg_channel, rpdev)
111
112/*
113 * We're allocating buffers of 512 bytes each for communications. The
114 * number of buffers will be computed from the number of buffers supported
115 * by the vring, upto a maximum of 512 buffers (256 in each direction).
116 *
117 * Each buffer will have 16 bytes for the msg header and 496 bytes for
118 * the payload.
119 *
120 * This will utilize a maximum total space of 256KB for the buffers.
121 *
122 * We might also want to add support for user-provided buffers in time.
123 * This will allow bigger buffer size flexibility, and can also be used
124 * to achieve zero-copy messaging.
125 *
126 * Note that these numbers are purely a decision of this driver - we
127 * can change this without changing anything in the firmware of the remote
128 * processor.
129 */
130#define MAX_RPMSG_NUM_BUFS (512)
131#define MAX_RPMSG_BUF_SIZE (512)
132
133/*
134 * Local addresses are dynamically allocated on-demand.
135 * We do not dynamically assign addresses from the low 1024 range,
136 * in order to reserve that address range for predefined services.
137 */
138#define RPMSG_RESERVED_ADDRESSES (1024)
139
140static void virtio_rpmsg_destroy_ept(struct rpmsg_endpoint *ept);
141static int virtio_rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len);
142static int virtio_rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len,
143 u32 dst);
144static int virtio_rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src,
145 u32 dst, void *data, int len);
146static int virtio_rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len);
147static int virtio_rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data,
148 int len, u32 dst);
149static int virtio_rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src,
150 u32 dst, void *data, int len);
151static ssize_t virtio_rpmsg_get_mtu(struct rpmsg_endpoint *ept);
152static struct rpmsg_device *__rpmsg_create_channel(struct virtproc_info *vrp,
153 struct rpmsg_channel_info *chinfo);
154
155static const struct rpmsg_endpoint_ops virtio_endpoint_ops = {
156 .destroy_ept = virtio_rpmsg_destroy_ept,
157 .send = virtio_rpmsg_send,
158 .sendto = virtio_rpmsg_sendto,
159 .send_offchannel = virtio_rpmsg_send_offchannel,
160 .trysend = virtio_rpmsg_trysend,
161 .trysendto = virtio_rpmsg_trysendto,
162 .trysend_offchannel = virtio_rpmsg_trysend_offchannel,
163 .get_mtu = virtio_rpmsg_get_mtu,
164};
165
166/**
167 * rpmsg_sg_init - initialize scatterlist according to cpu address location
168 * @sg: scatterlist to fill
169 * @cpu_addr: virtual address of the buffer
170 * @len: buffer length
171 *
172 * An internal function filling scatterlist according to virtual address
173 * location (in vmalloc or in kernel).
174 */
175static void
176rpmsg_sg_init(struct scatterlist *sg, void *cpu_addr, unsigned int len)
177{
178 if (is_vmalloc_addr(cpu_addr)) {
179 sg_init_table(sg, 1);
180 sg_set_page(sg, vmalloc_to_page(cpu_addr), len,
181 offset_in_page(cpu_addr));
182 } else {
183 WARN_ON(!virt_addr_valid(cpu_addr));
184 sg_init_one(sg, cpu_addr, len);
185 }
186}
187
188/**
189 * __ept_release() - deallocate an rpmsg endpoint
190 * @kref: the ept's reference count
191 *
192 * This function deallocates an ept, and is invoked when its @kref refcount
193 * drops to zero.
194 *
195 * Never invoke this function directly!
196 */
197static void __ept_release(struct kref *kref)
198{
199 struct rpmsg_endpoint *ept = container_of(kref, struct rpmsg_endpoint,
200 refcount);
201 /*
202 * At this point no one holds a reference to ept anymore,
203 * so we can directly free it
204 */
205 kfree(ept);
206}
207
208/* for more info, see below documentation of rpmsg_create_ept() */
209static struct rpmsg_endpoint *__rpmsg_create_ept(struct virtproc_info *vrp,
210 struct rpmsg_device *rpdev,
211 rpmsg_rx_cb_t cb,
212 void *priv, u32 addr)
213{
214 int id_min, id_max, id;
215 struct rpmsg_endpoint *ept;
216 struct device *dev = rpdev ? &rpdev->dev : &vrp->vdev->dev;
217
218 ept = kzalloc(sizeof(*ept), GFP_KERNEL);
219 if (!ept)
220 return NULL;
221
222 kref_init(&ept->refcount);
223 mutex_init(&ept->cb_lock);
224
225 ept->rpdev = rpdev;
226 ept->cb = cb;
227 ept->priv = priv;
228 ept->ops = &virtio_endpoint_ops;
229
230 /* do we need to allocate a local address ? */
231 if (addr == RPMSG_ADDR_ANY) {
232 id_min = RPMSG_RESERVED_ADDRESSES;
233 id_max = 0;
234 } else {
235 id_min = addr;
236 id_max = addr + 1;
237 }
238
239 mutex_lock(&vrp->endpoints_lock);
240
241 /* bind the endpoint to an rpmsg address (and allocate one if needed) */
242 id = idr_alloc(&vrp->endpoints, ept, id_min, id_max, GFP_KERNEL);
243 if (id < 0) {
244 dev_err(dev, "idr_alloc failed: %d\n", id);
245 goto free_ept;
246 }
247 ept->addr = id;
248
249 mutex_unlock(&vrp->endpoints_lock);
250
251 return ept;
252
253free_ept:
254 mutex_unlock(&vrp->endpoints_lock);
255 kref_put(&ept->refcount, __ept_release);
256 return NULL;
257}
258
259static struct rpmsg_device *virtio_rpmsg_create_channel(struct rpmsg_device *rpdev,
260 struct rpmsg_channel_info *chinfo)
261{
262 struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev);
263 struct virtproc_info *vrp = vch->vrp;
264
265 return __rpmsg_create_channel(vrp, chinfo);
266}
267
268static int virtio_rpmsg_release_channel(struct rpmsg_device *rpdev,
269 struct rpmsg_channel_info *chinfo)
270{
271 struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev);
272 struct virtproc_info *vrp = vch->vrp;
273
274 return rpmsg_unregister_device(&vrp->vdev->dev, chinfo);
275}
276
277static struct rpmsg_endpoint *virtio_rpmsg_create_ept(struct rpmsg_device *rpdev,
278 rpmsg_rx_cb_t cb,
279 void *priv,
280 struct rpmsg_channel_info chinfo)
281{
282 struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev);
283
284 return __rpmsg_create_ept(vch->vrp, rpdev, cb, priv, chinfo.src);
285}
286
287/**
288 * __rpmsg_destroy_ept() - destroy an existing rpmsg endpoint
289 * @vrp: virtproc which owns this ept
290 * @ept: endpoing to destroy
291 *
292 * An internal function which destroy an ept without assuming it is
293 * bound to an rpmsg channel. This is needed for handling the internal
294 * name service endpoint, which isn't bound to an rpmsg channel.
295 * See also __rpmsg_create_ept().
296 */
297static void
298__rpmsg_destroy_ept(struct virtproc_info *vrp, struct rpmsg_endpoint *ept)
299{
300 /* make sure new inbound messages can't find this ept anymore */
301 mutex_lock(&vrp->endpoints_lock);
302 idr_remove(&vrp->endpoints, ept->addr);
303 mutex_unlock(&vrp->endpoints_lock);
304
305 /* make sure in-flight inbound messages won't invoke cb anymore */
306 mutex_lock(&ept->cb_lock);
307 ept->cb = NULL;
308 mutex_unlock(&ept->cb_lock);
309
310 kref_put(&ept->refcount, __ept_release);
311}
312
313static void virtio_rpmsg_destroy_ept(struct rpmsg_endpoint *ept)
314{
315 struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(ept->rpdev);
316
317 __rpmsg_destroy_ept(vch->vrp, ept);
318}
319
320static int virtio_rpmsg_announce_create(struct rpmsg_device *rpdev)
321{
322 struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev);
323 struct virtproc_info *vrp = vch->vrp;
324 struct device *dev = &rpdev->dev;
325 int err = 0;
326
327 /* need to tell remote processor's name service about this channel ? */
328 if (rpdev->announce && rpdev->ept &&
329 virtio_has_feature(vrp->vdev, VIRTIO_RPMSG_F_NS)) {
330 struct rpmsg_ns_msg nsm;
331
332 strscpy_pad(nsm.name, rpdev->id.name, sizeof(nsm.name));
333 nsm.addr = cpu_to_rpmsg32(rpdev, rpdev->ept->addr);
334 nsm.flags = cpu_to_rpmsg32(rpdev, RPMSG_NS_CREATE);
335
336 err = rpmsg_sendto(rpdev->ept, &nsm, sizeof(nsm), RPMSG_NS_ADDR);
337 if (err)
338 dev_err(dev, "failed to announce service %d\n", err);
339 }
340
341 return err;
342}
343
344static int virtio_rpmsg_announce_destroy(struct rpmsg_device *rpdev)
345{
346 struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev);
347 struct virtproc_info *vrp = vch->vrp;
348 struct device *dev = &rpdev->dev;
349 int err = 0;
350
351 /* tell remote processor's name service we're removing this channel */
352 if (rpdev->announce && rpdev->ept &&
353 virtio_has_feature(vrp->vdev, VIRTIO_RPMSG_F_NS)) {
354 struct rpmsg_ns_msg nsm;
355
356 strscpy_pad(nsm.name, rpdev->id.name, sizeof(nsm.name));
357 nsm.addr = cpu_to_rpmsg32(rpdev, rpdev->ept->addr);
358 nsm.flags = cpu_to_rpmsg32(rpdev, RPMSG_NS_DESTROY);
359
360 err = rpmsg_sendto(rpdev->ept, &nsm, sizeof(nsm), RPMSG_NS_ADDR);
361 if (err)
362 dev_err(dev, "failed to announce service %d\n", err);
363 }
364
365 return err;
366}
367
368static const struct rpmsg_device_ops virtio_rpmsg_ops = {
369 .create_channel = virtio_rpmsg_create_channel,
370 .release_channel = virtio_rpmsg_release_channel,
371 .create_ept = virtio_rpmsg_create_ept,
372 .announce_create = virtio_rpmsg_announce_create,
373 .announce_destroy = virtio_rpmsg_announce_destroy,
374};
375
376static void virtio_rpmsg_release_device(struct device *dev)
377{
378 struct rpmsg_device *rpdev = to_rpmsg_device(dev);
379 struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev);
380
381 kfree(rpdev->driver_override);
382 kfree(vch);
383}
384
385/*
386 * create an rpmsg channel using its name and address info.
387 * this function will be used to create both static and dynamic
388 * channels.
389 */
390static struct rpmsg_device *__rpmsg_create_channel(struct virtproc_info *vrp,
391 struct rpmsg_channel_info *chinfo)
392{
393 struct virtio_rpmsg_channel *vch;
394 struct rpmsg_device *rpdev;
395 struct device *tmp, *dev = &vrp->vdev->dev;
396 int ret;
397
398 /* make sure a similar channel doesn't already exist */
399 tmp = rpmsg_find_device(dev, chinfo);
400 if (tmp) {
401 /* decrement the matched device's refcount back */
402 put_device(tmp);
403 dev_err(dev, "channel %s:%x:%x already exist\n",
404 chinfo->name, chinfo->src, chinfo->dst);
405 return NULL;
406 }
407
408 vch = kzalloc(sizeof(*vch), GFP_KERNEL);
409 if (!vch)
410 return NULL;
411
412 /* Link the channel to our vrp */
413 vch->vrp = vrp;
414
415 /* Assign public information to the rpmsg_device */
416 rpdev = &vch->rpdev;
417 rpdev->src = chinfo->src;
418 rpdev->dst = chinfo->dst;
419 rpdev->ops = &virtio_rpmsg_ops;
420 rpdev->little_endian = virtio_is_little_endian(vrp->vdev);
421
422 /*
423 * rpmsg server channels has predefined local address (for now),
424 * and their existence needs to be announced remotely
425 */
426 rpdev->announce = rpdev->src != RPMSG_ADDR_ANY;
427
428 strscpy(rpdev->id.name, chinfo->name, sizeof(rpdev->id.name));
429
430 rpdev->dev.parent = &vrp->vdev->dev;
431 rpdev->dev.release = virtio_rpmsg_release_device;
432 ret = rpmsg_register_device(rpdev);
433 if (ret)
434 return NULL;
435
436 return rpdev;
437}
438
439/* super simple buffer "allocator" that is just enough for now */
440static void *get_a_tx_buf(struct virtproc_info *vrp)
441{
442 unsigned int len;
443 void *ret;
444
445 /* support multiple concurrent senders */
446 mutex_lock(&vrp->tx_lock);
447
448 /*
449 * either pick the next unused tx buffer
450 * (half of our buffers are used for sending messages)
451 */
452 if (vrp->last_sbuf < vrp->num_bufs / 2)
453 ret = vrp->sbufs + vrp->buf_size * vrp->last_sbuf++;
454 /* or recycle a used one */
455 else
456 ret = virtqueue_get_buf(vrp->svq, &len);
457
458 mutex_unlock(&vrp->tx_lock);
459
460 return ret;
461}
462
463/**
464 * rpmsg_upref_sleepers() - enable "tx-complete" interrupts, if needed
465 * @vrp: virtual remote processor state
466 *
467 * This function is called before a sender is blocked, waiting for
468 * a tx buffer to become available.
469 *
470 * If we already have blocking senders, this function merely increases
471 * the "sleepers" reference count, and exits.
472 *
473 * Otherwise, if this is the first sender to block, we also enable
474 * virtio's tx callbacks, so we'd be immediately notified when a tx
475 * buffer is consumed (we rely on virtio's tx callback in order
476 * to wake up sleeping senders as soon as a tx buffer is used by the
477 * remote processor).
478 */
479static void rpmsg_upref_sleepers(struct virtproc_info *vrp)
480{
481 /* support multiple concurrent senders */
482 mutex_lock(&vrp->tx_lock);
483
484 /* are we the first sleeping context waiting for tx buffers ? */
485 if (atomic_inc_return(&vrp->sleepers) == 1)
486 /* enable "tx-complete" interrupts before dozing off */
487 virtqueue_enable_cb(vrp->svq);
488
489 mutex_unlock(&vrp->tx_lock);
490}
491
492/**
493 * rpmsg_downref_sleepers() - disable "tx-complete" interrupts, if needed
494 * @vrp: virtual remote processor state
495 *
496 * This function is called after a sender, that waited for a tx buffer
497 * to become available, is unblocked.
498 *
499 * If we still have blocking senders, this function merely decreases
500 * the "sleepers" reference count, and exits.
501 *
502 * Otherwise, if there are no more blocking senders, we also disable
503 * virtio's tx callbacks, to avoid the overhead incurred with handling
504 * those (now redundant) interrupts.
505 */
506static void rpmsg_downref_sleepers(struct virtproc_info *vrp)
507{
508 /* support multiple concurrent senders */
509 mutex_lock(&vrp->tx_lock);
510
511 /* are we the last sleeping context waiting for tx buffers ? */
512 if (atomic_dec_and_test(&vrp->sleepers))
513 /* disable "tx-complete" interrupts */
514 virtqueue_disable_cb(vrp->svq);
515
516 mutex_unlock(&vrp->tx_lock);
517}
518
519/**
520 * rpmsg_send_offchannel_raw() - send a message across to the remote processor
521 * @rpdev: the rpmsg channel
522 * @src: source address
523 * @dst: destination address
524 * @data: payload of message
525 * @len: length of payload
526 * @wait: indicates whether caller should block in case no TX buffers available
527 *
528 * This function is the base implementation for all of the rpmsg sending API.
529 *
530 * It will send @data of length @len to @dst, and say it's from @src. The
531 * message will be sent to the remote processor which the @rpdev channel
532 * belongs to.
533 *
534 * The message is sent using one of the TX buffers that are available for
535 * communication with this remote processor.
536 *
537 * If @wait is true, the caller will be blocked until either a TX buffer is
538 * available, or 15 seconds elapses (we don't want callers to
539 * sleep indefinitely due to misbehaving remote processors), and in that
540 * case -ERESTARTSYS is returned. The number '15' itself was picked
541 * arbitrarily; there's little point in asking drivers to provide a timeout
542 * value themselves.
543 *
544 * Otherwise, if @wait is false, and there are no TX buffers available,
545 * the function will immediately fail, and -ENOMEM will be returned.
546 *
547 * Normally drivers shouldn't use this function directly; instead, drivers
548 * should use the appropriate rpmsg_{try}send{to, _offchannel} API
549 * (see include/linux/rpmsg.h).
550 *
551 * Return: 0 on success and an appropriate error value on failure.
552 */
553static int rpmsg_send_offchannel_raw(struct rpmsg_device *rpdev,
554 u32 src, u32 dst,
555 void *data, int len, bool wait)
556{
557 struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev);
558 struct virtproc_info *vrp = vch->vrp;
559 struct device *dev = &rpdev->dev;
560 struct scatterlist sg;
561 struct rpmsg_hdr *msg;
562 int err;
563
564 /* bcasting isn't allowed */
565 if (src == RPMSG_ADDR_ANY || dst == RPMSG_ADDR_ANY) {
566 dev_err(dev, "invalid addr (src 0x%x, dst 0x%x)\n", src, dst);
567 return -EINVAL;
568 }
569
570 /*
571 * We currently use fixed-sized buffers, and therefore the payload
572 * length is limited.
573 *
574 * One of the possible improvements here is either to support
575 * user-provided buffers (and then we can also support zero-copy
576 * messaging), or to improve the buffer allocator, to support
577 * variable-length buffer sizes.
578 */
579 if (len > vrp->buf_size - sizeof(struct rpmsg_hdr)) {
580 dev_err(dev, "message is too big (%d)\n", len);
581 return -EMSGSIZE;
582 }
583
584 /* grab a buffer */
585 msg = get_a_tx_buf(vrp);
586 if (!msg && !wait)
587 return -ENOMEM;
588
589 /* no free buffer ? wait for one (but bail after 15 seconds) */
590 while (!msg) {
591 /* enable "tx-complete" interrupts, if not already enabled */
592 rpmsg_upref_sleepers(vrp);
593
594 /*
595 * sleep until a free buffer is available or 15 secs elapse.
596 * the timeout period is not configurable because there's
597 * little point in asking drivers to specify that.
598 * if later this happens to be required, it'd be easy to add.
599 */
600 err = wait_event_interruptible_timeout(vrp->sendq,
601 (msg = get_a_tx_buf(vrp)),
602 msecs_to_jiffies(15000));
603
604 /* disable "tx-complete" interrupts if we're the last sleeper */
605 rpmsg_downref_sleepers(vrp);
606
607 /* timeout ? */
608 if (!err) {
609 dev_err(dev, "timeout waiting for a tx buffer\n");
610 return -ERESTARTSYS;
611 }
612 }
613
614 msg->len = cpu_to_rpmsg16(rpdev, len);
615 msg->flags = 0;
616 msg->src = cpu_to_rpmsg32(rpdev, src);
617 msg->dst = cpu_to_rpmsg32(rpdev, dst);
618 msg->reserved = 0;
619 memcpy(msg->data, data, len);
620
621 dev_dbg(dev, "TX From 0x%x, To 0x%x, Len %d, Flags %d, Reserved %d\n",
622 src, dst, len, msg->flags, msg->reserved);
623#if defined(CONFIG_DYNAMIC_DEBUG)
624 dynamic_hex_dump("rpmsg_virtio TX: ", DUMP_PREFIX_NONE, 16, 1,
625 msg, sizeof(*msg) + len, true);
626#endif
627
628 rpmsg_sg_init(&sg, msg, sizeof(*msg) + len);
629
630 mutex_lock(&vrp->tx_lock);
631
632 /* add message to the remote processor's virtqueue */
633 err = virtqueue_add_outbuf(vrp->svq, &sg, 1, msg, GFP_KERNEL);
634 if (err) {
635 /*
636 * need to reclaim the buffer here, otherwise it's lost
637 * (memory won't leak, but rpmsg won't use it again for TX).
638 * this will wait for a buffer management overhaul.
639 */
640 dev_err(dev, "virtqueue_add_outbuf failed: %d\n", err);
641 goto out;
642 }
643
644 /* tell the remote processor it has a pending message to read */
645 virtqueue_kick(vrp->svq);
646out:
647 mutex_unlock(&vrp->tx_lock);
648 return err;
649}
650
651static int virtio_rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len)
652{
653 struct rpmsg_device *rpdev = ept->rpdev;
654 u32 src = ept->addr, dst = rpdev->dst;
655
656 return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
657}
658
659static int virtio_rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len,
660 u32 dst)
661{
662 struct rpmsg_device *rpdev = ept->rpdev;
663 u32 src = ept->addr;
664
665 return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
666}
667
668static int virtio_rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src,
669 u32 dst, void *data, int len)
670{
671 struct rpmsg_device *rpdev = ept->rpdev;
672
673 return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
674}
675
676static int virtio_rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len)
677{
678 struct rpmsg_device *rpdev = ept->rpdev;
679 u32 src = ept->addr, dst = rpdev->dst;
680
681 return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
682}
683
684static int virtio_rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data,
685 int len, u32 dst)
686{
687 struct rpmsg_device *rpdev = ept->rpdev;
688 u32 src = ept->addr;
689
690 return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
691}
692
693static int virtio_rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src,
694 u32 dst, void *data, int len)
695{
696 struct rpmsg_device *rpdev = ept->rpdev;
697
698 return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
699}
700
701static ssize_t virtio_rpmsg_get_mtu(struct rpmsg_endpoint *ept)
702{
703 struct rpmsg_device *rpdev = ept->rpdev;
704 struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev);
705
706 return vch->vrp->buf_size - sizeof(struct rpmsg_hdr);
707}
708
709static int rpmsg_recv_single(struct virtproc_info *vrp, struct device *dev,
710 struct rpmsg_hdr *msg, unsigned int len)
711{
712 struct rpmsg_endpoint *ept;
713 struct scatterlist sg;
714 bool little_endian = virtio_is_little_endian(vrp->vdev);
715 unsigned int msg_len = __rpmsg16_to_cpu(little_endian, msg->len);
716 int err;
717
718 dev_dbg(dev, "From: 0x%x, To: 0x%x, Len: %d, Flags: %d, Reserved: %d\n",
719 __rpmsg32_to_cpu(little_endian, msg->src),
720 __rpmsg32_to_cpu(little_endian, msg->dst), msg_len,
721 __rpmsg16_to_cpu(little_endian, msg->flags),
722 __rpmsg32_to_cpu(little_endian, msg->reserved));
723#if defined(CONFIG_DYNAMIC_DEBUG)
724 dynamic_hex_dump("rpmsg_virtio RX: ", DUMP_PREFIX_NONE, 16, 1,
725 msg, sizeof(*msg) + msg_len, true);
726#endif
727
728 /*
729 * We currently use fixed-sized buffers, so trivially sanitize
730 * the reported payload length.
731 */
732 if (len > vrp->buf_size ||
733 msg_len > (len - sizeof(struct rpmsg_hdr))) {
734 dev_warn(dev, "inbound msg too big: (%d, %d)\n", len, msg_len);
735 return -EINVAL;
736 }
737
738 /* use the dst addr to fetch the callback of the appropriate user */
739 mutex_lock(&vrp->endpoints_lock);
740
741 ept = idr_find(&vrp->endpoints, __rpmsg32_to_cpu(little_endian, msg->dst));
742
743 /* let's make sure no one deallocates ept while we use it */
744 if (ept)
745 kref_get(&ept->refcount);
746
747 mutex_unlock(&vrp->endpoints_lock);
748
749 if (ept) {
750 /* make sure ept->cb doesn't go away while we use it */
751 mutex_lock(&ept->cb_lock);
752
753 if (ept->cb)
754 ept->cb(ept->rpdev, msg->data, msg_len, ept->priv,
755 __rpmsg32_to_cpu(little_endian, msg->src));
756
757 mutex_unlock(&ept->cb_lock);
758
759 /* farewell, ept, we don't need you anymore */
760 kref_put(&ept->refcount, __ept_release);
761 } else
762 dev_warn_ratelimited(dev, "msg received with no recipient\n");
763
764 /* publish the real size of the buffer */
765 rpmsg_sg_init(&sg, msg, vrp->buf_size);
766
767 /* add the buffer back to the remote processor's virtqueue */
768 err = virtqueue_add_inbuf(vrp->rvq, &sg, 1, msg, GFP_KERNEL);
769 if (err < 0) {
770 dev_err(dev, "failed to add a virtqueue buffer: %d\n", err);
771 return err;
772 }
773
774 return 0;
775}
776
777/* called when an rx buffer is used, and it's time to digest a message */
778static void rpmsg_recv_done(struct virtqueue *rvq)
779{
780 struct virtproc_info *vrp = rvq->vdev->priv;
781 struct device *dev = &rvq->vdev->dev;
782 struct rpmsg_hdr *msg;
783 unsigned int len, msgs_received = 0;
784 int err;
785
786 msg = virtqueue_get_buf(rvq, &len);
787 if (!msg) {
788 dev_err(dev, "uhm, incoming signal, but no used buffer ?\n");
789 return;
790 }
791
792 while (msg) {
793 err = rpmsg_recv_single(vrp, dev, msg, len);
794 if (err)
795 break;
796
797 msgs_received++;
798
799 msg = virtqueue_get_buf(rvq, &len);
800 }
801
802 dev_dbg(dev, "Received %u messages\n", msgs_received);
803
804 /* tell the remote processor we added another available rx buffer */
805 if (msgs_received)
806 virtqueue_kick(vrp->rvq);
807}
808
809/*
810 * This is invoked whenever the remote processor completed processing
811 * a TX msg we just sent it, and the buffer is put back to the used ring.
812 *
813 * Normally, though, we suppress this "tx complete" interrupt in order to
814 * avoid the incurred overhead.
815 */
816static void rpmsg_xmit_done(struct virtqueue *svq)
817{
818 struct virtproc_info *vrp = svq->vdev->priv;
819
820 dev_dbg(&svq->vdev->dev, "%s\n", __func__);
821
822 /* wake up potential senders that are waiting for a tx buffer */
823 wake_up_interruptible(&vrp->sendq);
824}
825
826/*
827 * Called to expose to user a /dev/rpmsg_ctrlX interface allowing to
828 * create endpoint-to-endpoint communication without associated RPMsg channel.
829 * The endpoints are rattached to the ctrldev RPMsg device.
830 */
831static struct rpmsg_device *rpmsg_virtio_add_ctrl_dev(struct virtio_device *vdev)
832{
833 struct virtproc_info *vrp = vdev->priv;
834 struct virtio_rpmsg_channel *vch;
835 struct rpmsg_device *rpdev_ctrl;
836 int err = 0;
837
838 vch = kzalloc(sizeof(*vch), GFP_KERNEL);
839 if (!vch)
840 return ERR_PTR(-ENOMEM);
841
842 /* Link the channel to the vrp */
843 vch->vrp = vrp;
844
845 /* Assign public information to the rpmsg_device */
846 rpdev_ctrl = &vch->rpdev;
847 rpdev_ctrl->ops = &virtio_rpmsg_ops;
848
849 rpdev_ctrl->dev.parent = &vrp->vdev->dev;
850 rpdev_ctrl->dev.release = virtio_rpmsg_release_device;
851 rpdev_ctrl->little_endian = virtio_is_little_endian(vrp->vdev);
852
853 err = rpmsg_ctrldev_register_device(rpdev_ctrl);
854 if (err) {
855 /* vch will be free in virtio_rpmsg_release_device() */
856 return ERR_PTR(err);
857 }
858
859 return rpdev_ctrl;
860}
861
862static void rpmsg_virtio_del_ctrl_dev(struct rpmsg_device *rpdev_ctrl)
863{
864 if (!rpdev_ctrl)
865 return;
866 device_unregister(&rpdev_ctrl->dev);
867}
868
869static int rpmsg_probe(struct virtio_device *vdev)
870{
871 vq_callback_t *vq_cbs[] = { rpmsg_recv_done, rpmsg_xmit_done };
872 static const char * const names[] = { "input", "output" };
873 struct virtqueue *vqs[2];
874 struct virtproc_info *vrp;
875 struct virtio_rpmsg_channel *vch = NULL;
876 struct rpmsg_device *rpdev_ns, *rpdev_ctrl;
877 void *bufs_va;
878 int err = 0, i;
879 size_t total_buf_space;
880 bool notify;
881
882 vrp = kzalloc(sizeof(*vrp), GFP_KERNEL);
883 if (!vrp)
884 return -ENOMEM;
885
886 vrp->vdev = vdev;
887
888 idr_init(&vrp->endpoints);
889 mutex_init(&vrp->endpoints_lock);
890 mutex_init(&vrp->tx_lock);
891 init_waitqueue_head(&vrp->sendq);
892
893 /* We expect two virtqueues, rx and tx (and in this order) */
894 err = virtio_find_vqs(vdev, 2, vqs, vq_cbs, names, NULL);
895 if (err)
896 goto free_vrp;
897
898 vrp->rvq = vqs[0];
899 vrp->svq = vqs[1];
900
901 /* we expect symmetric tx/rx vrings */
902 WARN_ON(virtqueue_get_vring_size(vrp->rvq) !=
903 virtqueue_get_vring_size(vrp->svq));
904
905 /* we need less buffers if vrings are small */
906 if (virtqueue_get_vring_size(vrp->rvq) < MAX_RPMSG_NUM_BUFS / 2)
907 vrp->num_bufs = virtqueue_get_vring_size(vrp->rvq) * 2;
908 else
909 vrp->num_bufs = MAX_RPMSG_NUM_BUFS;
910
911 vrp->buf_size = MAX_RPMSG_BUF_SIZE;
912
913 total_buf_space = vrp->num_bufs * vrp->buf_size;
914
915 /* allocate coherent memory for the buffers */
916 bufs_va = dma_alloc_coherent(vdev->dev.parent,
917 total_buf_space, &vrp->bufs_dma,
918 GFP_KERNEL);
919 if (!bufs_va) {
920 err = -ENOMEM;
921 goto vqs_del;
922 }
923
924 dev_dbg(&vdev->dev, "buffers: va %pK, dma %pad\n",
925 bufs_va, &vrp->bufs_dma);
926
927 /* half of the buffers is dedicated for RX */
928 vrp->rbufs = bufs_va;
929
930 /* and half is dedicated for TX */
931 vrp->sbufs = bufs_va + total_buf_space / 2;
932
933 /* set up the receive buffers */
934 for (i = 0; i < vrp->num_bufs / 2; i++) {
935 struct scatterlist sg;
936 void *cpu_addr = vrp->rbufs + i * vrp->buf_size;
937
938 rpmsg_sg_init(&sg, cpu_addr, vrp->buf_size);
939
940 err = virtqueue_add_inbuf(vrp->rvq, &sg, 1, cpu_addr,
941 GFP_KERNEL);
942 WARN_ON(err); /* sanity check; this can't really happen */
943 }
944
945 /* suppress "tx-complete" interrupts */
946 virtqueue_disable_cb(vrp->svq);
947
948 vdev->priv = vrp;
949
950 rpdev_ctrl = rpmsg_virtio_add_ctrl_dev(vdev);
951 if (IS_ERR(rpdev_ctrl)) {
952 err = PTR_ERR(rpdev_ctrl);
953 goto free_coherent;
954 }
955
956 /* if supported by the remote processor, enable the name service */
957 if (virtio_has_feature(vdev, VIRTIO_RPMSG_F_NS)) {
958 vch = kzalloc(sizeof(*vch), GFP_KERNEL);
959 if (!vch) {
960 err = -ENOMEM;
961 goto free_ctrldev;
962 }
963
964 /* Link the channel to our vrp */
965 vch->vrp = vrp;
966
967 /* Assign public information to the rpmsg_device */
968 rpdev_ns = &vch->rpdev;
969 rpdev_ns->ops = &virtio_rpmsg_ops;
970 rpdev_ns->little_endian = virtio_is_little_endian(vrp->vdev);
971
972 rpdev_ns->dev.parent = &vrp->vdev->dev;
973 rpdev_ns->dev.release = virtio_rpmsg_release_device;
974
975 err = rpmsg_ns_register_device(rpdev_ns);
976 if (err)
977 /* vch will be free in virtio_rpmsg_release_device() */
978 goto free_ctrldev;
979 }
980
981 /*
982 * Prepare to kick but don't notify yet - we can't do this before
983 * device is ready.
984 */
985 notify = virtqueue_kick_prepare(vrp->rvq);
986
987 /* From this point on, we can notify and get callbacks. */
988 virtio_device_ready(vdev);
989
990 /* tell the remote processor it can start sending messages */
991 /*
992 * this might be concurrent with callbacks, but we are only
993 * doing notify, not a full kick here, so that's ok.
994 */
995 if (notify)
996 virtqueue_notify(vrp->rvq);
997
998 dev_info(&vdev->dev, "rpmsg host is online\n");
999
1000 return 0;
1001
1002free_ctrldev:
1003 rpmsg_virtio_del_ctrl_dev(rpdev_ctrl);
1004free_coherent:
1005 dma_free_coherent(vdev->dev.parent, total_buf_space,
1006 bufs_va, vrp->bufs_dma);
1007vqs_del:
1008 vdev->config->del_vqs(vrp->vdev);
1009free_vrp:
1010 kfree(vrp);
1011 return err;
1012}
1013
1014static int rpmsg_remove_device(struct device *dev, void *data)
1015{
1016 device_unregister(dev);
1017
1018 return 0;
1019}
1020
1021static void rpmsg_remove(struct virtio_device *vdev)
1022{
1023 struct virtproc_info *vrp = vdev->priv;
1024 size_t total_buf_space = vrp->num_bufs * vrp->buf_size;
1025 int ret;
1026
1027 virtio_reset_device(vdev);
1028
1029 ret = device_for_each_child(&vdev->dev, NULL, rpmsg_remove_device);
1030 if (ret)
1031 dev_warn(&vdev->dev, "can't remove rpmsg device: %d\n", ret);
1032
1033 idr_destroy(&vrp->endpoints);
1034
1035 vdev->config->del_vqs(vrp->vdev);
1036
1037 dma_free_coherent(vdev->dev.parent, total_buf_space,
1038 vrp->rbufs, vrp->bufs_dma);
1039
1040 kfree(vrp);
1041}
1042
1043static struct virtio_device_id id_table[] = {
1044 { VIRTIO_ID_RPMSG, VIRTIO_DEV_ANY_ID },
1045 { 0 },
1046};
1047
1048static unsigned int features[] = {
1049 VIRTIO_RPMSG_F_NS,
1050};
1051
1052static struct virtio_driver virtio_ipc_driver = {
1053 .feature_table = features,
1054 .feature_table_size = ARRAY_SIZE(features),
1055 .driver.name = KBUILD_MODNAME,
1056 .driver.owner = THIS_MODULE,
1057 .id_table = id_table,
1058 .probe = rpmsg_probe,
1059 .remove = rpmsg_remove,
1060};
1061
1062static int __init rpmsg_init(void)
1063{
1064 int ret;
1065
1066 ret = register_virtio_driver(&virtio_ipc_driver);
1067 if (ret)
1068 pr_err("failed to register virtio driver: %d\n", ret);
1069
1070 return ret;
1071}
1072subsys_initcall(rpmsg_init);
1073
1074static void __exit rpmsg_fini(void)
1075{
1076 unregister_virtio_driver(&virtio_ipc_driver);
1077}
1078module_exit(rpmsg_fini);
1079
1080MODULE_DEVICE_TABLE(virtio, id_table);
1081MODULE_DESCRIPTION("Virtio-based remote processor messaging bus");
1082MODULE_LICENSE("GPL v2");
1/*
2 * Virtio-based remote processor messaging bus
3 *
4 * Copyright (C) 2011 Texas Instruments, Inc.
5 * Copyright (C) 2011 Google, Inc.
6 *
7 * Ohad Ben-Cohen <ohad@wizery.com>
8 * Brian Swetland <swetland@google.com>
9 *
10 * This software is licensed under the terms of the GNU General Public
11 * License version 2, as published by the Free Software Foundation, and
12 * may be copied, distributed, and modified under those terms.
13 *
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
18 */
19
20#define pr_fmt(fmt) "%s: " fmt, __func__
21
22#include <linux/kernel.h>
23#include <linux/module.h>
24#include <linux/virtio.h>
25#include <linux/virtio_ids.h>
26#include <linux/virtio_config.h>
27#include <linux/scatterlist.h>
28#include <linux/dma-mapping.h>
29#include <linux/slab.h>
30#include <linux/idr.h>
31#include <linux/jiffies.h>
32#include <linux/sched.h>
33#include <linux/wait.h>
34#include <linux/rpmsg.h>
35#include <linux/mutex.h>
36
37/**
38 * struct virtproc_info - virtual remote processor state
39 * @vdev: the virtio device
40 * @rvq: rx virtqueue
41 * @svq: tx virtqueue
42 * @rbufs: kernel address of rx buffers
43 * @sbufs: kernel address of tx buffers
44 * @last_sbuf: index of last tx buffer used
45 * @bufs_dma: dma base addr of the buffers
46 * @tx_lock: protects svq, sbufs and sleepers, to allow concurrent senders.
47 * sending a message might require waking up a dozing remote
48 * processor, which involves sleeping, hence the mutex.
49 * @endpoints: idr of local endpoints, allows fast retrieval
50 * @endpoints_lock: lock of the endpoints set
51 * @sendq: wait queue of sending contexts waiting for a tx buffers
52 * @sleepers: number of senders that are waiting for a tx buffer
53 * @ns_ept: the bus's name service endpoint
54 *
55 * This structure stores the rpmsg state of a given virtio remote processor
56 * device (there might be several virtio proc devices for each physical
57 * remote processor).
58 */
59struct virtproc_info {
60 struct virtio_device *vdev;
61 struct virtqueue *rvq, *svq;
62 void *rbufs, *sbufs;
63 int last_sbuf;
64 dma_addr_t bufs_dma;
65 struct mutex tx_lock;
66 struct idr endpoints;
67 struct mutex endpoints_lock;
68 wait_queue_head_t sendq;
69 atomic_t sleepers;
70 struct rpmsg_endpoint *ns_ept;
71};
72
73/**
74 * struct rpmsg_channel_info - internal channel info representation
75 * @name: name of service
76 * @src: local address
77 * @dst: destination address
78 */
79struct rpmsg_channel_info {
80 char name[RPMSG_NAME_SIZE];
81 u32 src;
82 u32 dst;
83};
84
85#define to_rpmsg_channel(d) container_of(d, struct rpmsg_channel, dev)
86#define to_rpmsg_driver(d) container_of(d, struct rpmsg_driver, drv)
87
88/*
89 * We're allocating 512 buffers of 512 bytes for communications, and then
90 * using the first 256 buffers for RX, and the last 256 buffers for TX.
91 *
92 * Each buffer will have 16 bytes for the msg header and 496 bytes for
93 * the payload.
94 *
95 * This will require a total space of 256KB for the buffers.
96 *
97 * We might also want to add support for user-provided buffers in time.
98 * This will allow bigger buffer size flexibility, and can also be used
99 * to achieve zero-copy messaging.
100 *
101 * Note that these numbers are purely a decision of this driver - we
102 * can change this without changing anything in the firmware of the remote
103 * processor.
104 */
105#define RPMSG_NUM_BUFS (512)
106#define RPMSG_BUF_SIZE (512)
107#define RPMSG_TOTAL_BUF_SPACE (RPMSG_NUM_BUFS * RPMSG_BUF_SIZE)
108
109/*
110 * Local addresses are dynamically allocated on-demand.
111 * We do not dynamically assign addresses from the low 1024 range,
112 * in order to reserve that address range for predefined services.
113 */
114#define RPMSG_RESERVED_ADDRESSES (1024)
115
116/* Address 53 is reserved for advertising remote services */
117#define RPMSG_NS_ADDR (53)
118
119/* sysfs show configuration fields */
120#define rpmsg_show_attr(field, path, format_string) \
121static ssize_t \
122field##_show(struct device *dev, \
123 struct device_attribute *attr, char *buf) \
124{ \
125 struct rpmsg_channel *rpdev = to_rpmsg_channel(dev); \
126 \
127 return sprintf(buf, format_string, rpdev->path); \
128}
129
130/* for more info, see Documentation/ABI/testing/sysfs-bus-rpmsg */
131rpmsg_show_attr(name, id.name, "%s\n");
132rpmsg_show_attr(src, src, "0x%x\n");
133rpmsg_show_attr(dst, dst, "0x%x\n");
134rpmsg_show_attr(announce, announce ? "true" : "false", "%s\n");
135
136/*
137 * Unique (and free running) index for rpmsg devices.
138 *
139 * Yeah, we're not recycling those numbers (yet?). will be easy
140 * to change if/when we want to.
141 */
142static unsigned int rpmsg_dev_index;
143
144static ssize_t modalias_show(struct device *dev,
145 struct device_attribute *attr, char *buf)
146{
147 struct rpmsg_channel *rpdev = to_rpmsg_channel(dev);
148
149 return sprintf(buf, RPMSG_DEVICE_MODALIAS_FMT "\n", rpdev->id.name);
150}
151
152static struct device_attribute rpmsg_dev_attrs[] = {
153 __ATTR_RO(name),
154 __ATTR_RO(modalias),
155 __ATTR_RO(dst),
156 __ATTR_RO(src),
157 __ATTR_RO(announce),
158 __ATTR_NULL
159};
160
161/* rpmsg devices and drivers are matched using the service name */
162static inline int rpmsg_id_match(const struct rpmsg_channel *rpdev,
163 const struct rpmsg_device_id *id)
164{
165 return strncmp(id->name, rpdev->id.name, RPMSG_NAME_SIZE) == 0;
166}
167
168/* match rpmsg channel and rpmsg driver */
169static int rpmsg_dev_match(struct device *dev, struct device_driver *drv)
170{
171 struct rpmsg_channel *rpdev = to_rpmsg_channel(dev);
172 struct rpmsg_driver *rpdrv = to_rpmsg_driver(drv);
173 const struct rpmsg_device_id *ids = rpdrv->id_table;
174 unsigned int i;
175
176 for (i = 0; ids[i].name[0]; i++)
177 if (rpmsg_id_match(rpdev, &ids[i]))
178 return 1;
179
180 return 0;
181}
182
183static int rpmsg_uevent(struct device *dev, struct kobj_uevent_env *env)
184{
185 struct rpmsg_channel *rpdev = to_rpmsg_channel(dev);
186
187 return add_uevent_var(env, "MODALIAS=" RPMSG_DEVICE_MODALIAS_FMT,
188 rpdev->id.name);
189}
190
191/**
192 * __ept_release() - deallocate an rpmsg endpoint
193 * @kref: the ept's reference count
194 *
195 * This function deallocates an ept, and is invoked when its @kref refcount
196 * drops to zero.
197 *
198 * Never invoke this function directly!
199 */
200static void __ept_release(struct kref *kref)
201{
202 struct rpmsg_endpoint *ept = container_of(kref, struct rpmsg_endpoint,
203 refcount);
204 /*
205 * At this point no one holds a reference to ept anymore,
206 * so we can directly free it
207 */
208 kfree(ept);
209}
210
211/* for more info, see below documentation of rpmsg_create_ept() */
212static struct rpmsg_endpoint *__rpmsg_create_ept(struct virtproc_info *vrp,
213 struct rpmsg_channel *rpdev, rpmsg_rx_cb_t cb,
214 void *priv, u32 addr)
215{
216 int err, tmpaddr, request;
217 struct rpmsg_endpoint *ept;
218 struct device *dev = rpdev ? &rpdev->dev : &vrp->vdev->dev;
219
220 if (!idr_pre_get(&vrp->endpoints, GFP_KERNEL))
221 return NULL;
222
223 ept = kzalloc(sizeof(*ept), GFP_KERNEL);
224 if (!ept) {
225 dev_err(dev, "failed to kzalloc a new ept\n");
226 return NULL;
227 }
228
229 kref_init(&ept->refcount);
230 mutex_init(&ept->cb_lock);
231
232 ept->rpdev = rpdev;
233 ept->cb = cb;
234 ept->priv = priv;
235
236 /* do we need to allocate a local address ? */
237 request = addr == RPMSG_ADDR_ANY ? RPMSG_RESERVED_ADDRESSES : addr;
238
239 mutex_lock(&vrp->endpoints_lock);
240
241 /* bind the endpoint to an rpmsg address (and allocate one if needed) */
242 err = idr_get_new_above(&vrp->endpoints, ept, request, &tmpaddr);
243 if (err) {
244 dev_err(dev, "idr_get_new_above failed: %d\n", err);
245 goto free_ept;
246 }
247
248 /* make sure the user's address request is fulfilled, if relevant */
249 if (addr != RPMSG_ADDR_ANY && tmpaddr != addr) {
250 dev_err(dev, "address 0x%x already in use\n", addr);
251 goto rem_idr;
252 }
253
254 ept->addr = tmpaddr;
255
256 mutex_unlock(&vrp->endpoints_lock);
257
258 return ept;
259
260rem_idr:
261 idr_remove(&vrp->endpoints, request);
262free_ept:
263 mutex_unlock(&vrp->endpoints_lock);
264 kref_put(&ept->refcount, __ept_release);
265 return NULL;
266}
267
268/**
269 * rpmsg_create_ept() - create a new rpmsg_endpoint
270 * @rpdev: rpmsg channel device
271 * @cb: rx callback handler
272 * @priv: private data for the driver's use
273 * @addr: local rpmsg address to bind with @cb
274 *
275 * Every rpmsg address in the system is bound to an rx callback (so when
276 * inbound messages arrive, they are dispatched by the rpmsg bus using the
277 * appropriate callback handler) by means of an rpmsg_endpoint struct.
278 *
279 * This function allows drivers to create such an endpoint, and by that,
280 * bind a callback, and possibly some private data too, to an rpmsg address
281 * (either one that is known in advance, or one that will be dynamically
282 * assigned for them).
283 *
284 * Simple rpmsg drivers need not call rpmsg_create_ept, because an endpoint
285 * is already created for them when they are probed by the rpmsg bus
286 * (using the rx callback provided when they registered to the rpmsg bus).
287 *
288 * So things should just work for simple drivers: they already have an
289 * endpoint, their rx callback is bound to their rpmsg address, and when
290 * relevant inbound messages arrive (i.e. messages which their dst address
291 * equals to the src address of their rpmsg channel), the driver's handler
292 * is invoked to process it.
293 *
294 * That said, more complicated drivers might do need to allocate
295 * additional rpmsg addresses, and bind them to different rx callbacks.
296 * To accomplish that, those drivers need to call this function.
297 *
298 * Drivers should provide their @rpdev channel (so the new endpoint would belong
299 * to the same remote processor their channel belongs to), an rx callback
300 * function, an optional private data (which is provided back when the
301 * rx callback is invoked), and an address they want to bind with the
302 * callback. If @addr is RPMSG_ADDR_ANY, then rpmsg_create_ept will
303 * dynamically assign them an available rpmsg address (drivers should have
304 * a very good reason why not to always use RPMSG_ADDR_ANY here).
305 *
306 * Returns a pointer to the endpoint on success, or NULL on error.
307 */
308struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_channel *rpdev,
309 rpmsg_rx_cb_t cb, void *priv, u32 addr)
310{
311 return __rpmsg_create_ept(rpdev->vrp, rpdev, cb, priv, addr);
312}
313EXPORT_SYMBOL(rpmsg_create_ept);
314
315/**
316 * __rpmsg_destroy_ept() - destroy an existing rpmsg endpoint
317 * @vrp: virtproc which owns this ept
318 * @ept: endpoing to destroy
319 *
320 * An internal function which destroy an ept without assuming it is
321 * bound to an rpmsg channel. This is needed for handling the internal
322 * name service endpoint, which isn't bound to an rpmsg channel.
323 * See also __rpmsg_create_ept().
324 */
325static void
326__rpmsg_destroy_ept(struct virtproc_info *vrp, struct rpmsg_endpoint *ept)
327{
328 /* make sure new inbound messages can't find this ept anymore */
329 mutex_lock(&vrp->endpoints_lock);
330 idr_remove(&vrp->endpoints, ept->addr);
331 mutex_unlock(&vrp->endpoints_lock);
332
333 /* make sure in-flight inbound messages won't invoke cb anymore */
334 mutex_lock(&ept->cb_lock);
335 ept->cb = NULL;
336 mutex_unlock(&ept->cb_lock);
337
338 kref_put(&ept->refcount, __ept_release);
339}
340
341/**
342 * rpmsg_destroy_ept() - destroy an existing rpmsg endpoint
343 * @ept: endpoing to destroy
344 *
345 * Should be used by drivers to destroy an rpmsg endpoint previously
346 * created with rpmsg_create_ept().
347 */
348void rpmsg_destroy_ept(struct rpmsg_endpoint *ept)
349{
350 __rpmsg_destroy_ept(ept->rpdev->vrp, ept);
351}
352EXPORT_SYMBOL(rpmsg_destroy_ept);
353
354/*
355 * when an rpmsg driver is probed with a channel, we seamlessly create
356 * it an endpoint, binding its rx callback to a unique local rpmsg
357 * address.
358 *
359 * if we need to, we also announce about this channel to the remote
360 * processor (needed in case the driver is exposing an rpmsg service).
361 */
362static int rpmsg_dev_probe(struct device *dev)
363{
364 struct rpmsg_channel *rpdev = to_rpmsg_channel(dev);
365 struct rpmsg_driver *rpdrv = to_rpmsg_driver(rpdev->dev.driver);
366 struct virtproc_info *vrp = rpdev->vrp;
367 struct rpmsg_endpoint *ept;
368 int err;
369
370 ept = rpmsg_create_ept(rpdev, rpdrv->callback, NULL, rpdev->src);
371 if (!ept) {
372 dev_err(dev, "failed to create endpoint\n");
373 err = -ENOMEM;
374 goto out;
375 }
376
377 rpdev->ept = ept;
378 rpdev->src = ept->addr;
379
380 err = rpdrv->probe(rpdev);
381 if (err) {
382 dev_err(dev, "%s: failed: %d\n", __func__, err);
383 rpmsg_destroy_ept(ept);
384 goto out;
385 }
386
387 /* need to tell remote processor's name service about this channel ? */
388 if (rpdev->announce &&
389 virtio_has_feature(vrp->vdev, VIRTIO_RPMSG_F_NS)) {
390 struct rpmsg_ns_msg nsm;
391
392 strncpy(nsm.name, rpdev->id.name, RPMSG_NAME_SIZE);
393 nsm.addr = rpdev->src;
394 nsm.flags = RPMSG_NS_CREATE;
395
396 err = rpmsg_sendto(rpdev, &nsm, sizeof(nsm), RPMSG_NS_ADDR);
397 if (err)
398 dev_err(dev, "failed to announce service %d\n", err);
399 }
400
401out:
402 return err;
403}
404
405static int rpmsg_dev_remove(struct device *dev)
406{
407 struct rpmsg_channel *rpdev = to_rpmsg_channel(dev);
408 struct rpmsg_driver *rpdrv = to_rpmsg_driver(rpdev->dev.driver);
409 struct virtproc_info *vrp = rpdev->vrp;
410 int err = 0;
411
412 /* tell remote processor's name service we're removing this channel */
413 if (rpdev->announce &&
414 virtio_has_feature(vrp->vdev, VIRTIO_RPMSG_F_NS)) {
415 struct rpmsg_ns_msg nsm;
416
417 strncpy(nsm.name, rpdev->id.name, RPMSG_NAME_SIZE);
418 nsm.addr = rpdev->src;
419 nsm.flags = RPMSG_NS_DESTROY;
420
421 err = rpmsg_sendto(rpdev, &nsm, sizeof(nsm), RPMSG_NS_ADDR);
422 if (err)
423 dev_err(dev, "failed to announce service %d\n", err);
424 }
425
426 rpdrv->remove(rpdev);
427
428 rpmsg_destroy_ept(rpdev->ept);
429
430 return err;
431}
432
433static struct bus_type rpmsg_bus = {
434 .name = "rpmsg",
435 .match = rpmsg_dev_match,
436 .dev_attrs = rpmsg_dev_attrs,
437 .uevent = rpmsg_uevent,
438 .probe = rpmsg_dev_probe,
439 .remove = rpmsg_dev_remove,
440};
441
442/**
443 * register_rpmsg_driver() - register an rpmsg driver with the rpmsg bus
444 * @rpdrv: pointer to a struct rpmsg_driver
445 *
446 * Returns 0 on success, and an appropriate error value on failure.
447 */
448int register_rpmsg_driver(struct rpmsg_driver *rpdrv)
449{
450 rpdrv->drv.bus = &rpmsg_bus;
451 return driver_register(&rpdrv->drv);
452}
453EXPORT_SYMBOL(register_rpmsg_driver);
454
455/**
456 * unregister_rpmsg_driver() - unregister an rpmsg driver from the rpmsg bus
457 * @rpdrv: pointer to a struct rpmsg_driver
458 *
459 * Returns 0 on success, and an appropriate error value on failure.
460 */
461void unregister_rpmsg_driver(struct rpmsg_driver *rpdrv)
462{
463 driver_unregister(&rpdrv->drv);
464}
465EXPORT_SYMBOL(unregister_rpmsg_driver);
466
467static void rpmsg_release_device(struct device *dev)
468{
469 struct rpmsg_channel *rpdev = to_rpmsg_channel(dev);
470
471 kfree(rpdev);
472}
473
474/*
475 * match an rpmsg channel with a channel info struct.
476 * this is used to make sure we're not creating rpmsg devices for channels
477 * that already exist.
478 */
479static int rpmsg_channel_match(struct device *dev, void *data)
480{
481 struct rpmsg_channel_info *chinfo = data;
482 struct rpmsg_channel *rpdev = to_rpmsg_channel(dev);
483
484 if (chinfo->src != RPMSG_ADDR_ANY && chinfo->src != rpdev->src)
485 return 0;
486
487 if (chinfo->dst != RPMSG_ADDR_ANY && chinfo->dst != rpdev->dst)
488 return 0;
489
490 if (strncmp(chinfo->name, rpdev->id.name, RPMSG_NAME_SIZE))
491 return 0;
492
493 /* found a match ! */
494 return 1;
495}
496
497/*
498 * create an rpmsg channel using its name and address info.
499 * this function will be used to create both static and dynamic
500 * channels.
501 */
502static struct rpmsg_channel *rpmsg_create_channel(struct virtproc_info *vrp,
503 struct rpmsg_channel_info *chinfo)
504{
505 struct rpmsg_channel *rpdev;
506 struct device *tmp, *dev = &vrp->vdev->dev;
507 int ret;
508
509 /* make sure a similar channel doesn't already exist */
510 tmp = device_find_child(dev, chinfo, rpmsg_channel_match);
511 if (tmp) {
512 /* decrement the matched device's refcount back */
513 put_device(tmp);
514 dev_err(dev, "channel %s:%x:%x already exist\n",
515 chinfo->name, chinfo->src, chinfo->dst);
516 return NULL;
517 }
518
519 rpdev = kzalloc(sizeof(struct rpmsg_channel), GFP_KERNEL);
520 if (!rpdev) {
521 pr_err("kzalloc failed\n");
522 return NULL;
523 }
524
525 rpdev->vrp = vrp;
526 rpdev->src = chinfo->src;
527 rpdev->dst = chinfo->dst;
528
529 /*
530 * rpmsg server channels has predefined local address (for now),
531 * and their existence needs to be announced remotely
532 */
533 rpdev->announce = rpdev->src != RPMSG_ADDR_ANY ? true : false;
534
535 strncpy(rpdev->id.name, chinfo->name, RPMSG_NAME_SIZE);
536
537 /* very simple device indexing plumbing which is enough for now */
538 dev_set_name(&rpdev->dev, "rpmsg%d", rpmsg_dev_index++);
539
540 rpdev->dev.parent = &vrp->vdev->dev;
541 rpdev->dev.bus = &rpmsg_bus;
542 rpdev->dev.release = rpmsg_release_device;
543
544 ret = device_register(&rpdev->dev);
545 if (ret) {
546 dev_err(dev, "device_register failed: %d\n", ret);
547 put_device(&rpdev->dev);
548 return NULL;
549 }
550
551 return rpdev;
552}
553
554/*
555 * find an existing channel using its name + address properties,
556 * and destroy it
557 */
558static int rpmsg_destroy_channel(struct virtproc_info *vrp,
559 struct rpmsg_channel_info *chinfo)
560{
561 struct virtio_device *vdev = vrp->vdev;
562 struct device *dev;
563
564 dev = device_find_child(&vdev->dev, chinfo, rpmsg_channel_match);
565 if (!dev)
566 return -EINVAL;
567
568 device_unregister(dev);
569
570 put_device(dev);
571
572 return 0;
573}
574
575/* super simple buffer "allocator" that is just enough for now */
576static void *get_a_tx_buf(struct virtproc_info *vrp)
577{
578 unsigned int len;
579 void *ret;
580
581 /* support multiple concurrent senders */
582 mutex_lock(&vrp->tx_lock);
583
584 /*
585 * either pick the next unused tx buffer
586 * (half of our buffers are used for sending messages)
587 */
588 if (vrp->last_sbuf < RPMSG_NUM_BUFS / 2)
589 ret = vrp->sbufs + RPMSG_BUF_SIZE * vrp->last_sbuf++;
590 /* or recycle a used one */
591 else
592 ret = virtqueue_get_buf(vrp->svq, &len);
593
594 mutex_unlock(&vrp->tx_lock);
595
596 return ret;
597}
598
599/**
600 * rpmsg_upref_sleepers() - enable "tx-complete" interrupts, if needed
601 * @vrp: virtual remote processor state
602 *
603 * This function is called before a sender is blocked, waiting for
604 * a tx buffer to become available.
605 *
606 * If we already have blocking senders, this function merely increases
607 * the "sleepers" reference count, and exits.
608 *
609 * Otherwise, if this is the first sender to block, we also enable
610 * virtio's tx callbacks, so we'd be immediately notified when a tx
611 * buffer is consumed (we rely on virtio's tx callback in order
612 * to wake up sleeping senders as soon as a tx buffer is used by the
613 * remote processor).
614 */
615static void rpmsg_upref_sleepers(struct virtproc_info *vrp)
616{
617 /* support multiple concurrent senders */
618 mutex_lock(&vrp->tx_lock);
619
620 /* are we the first sleeping context waiting for tx buffers ? */
621 if (atomic_inc_return(&vrp->sleepers) == 1)
622 /* enable "tx-complete" interrupts before dozing off */
623 virtqueue_enable_cb(vrp->svq);
624
625 mutex_unlock(&vrp->tx_lock);
626}
627
628/**
629 * rpmsg_downref_sleepers() - disable "tx-complete" interrupts, if needed
630 * @vrp: virtual remote processor state
631 *
632 * This function is called after a sender, that waited for a tx buffer
633 * to become available, is unblocked.
634 *
635 * If we still have blocking senders, this function merely decreases
636 * the "sleepers" reference count, and exits.
637 *
638 * Otherwise, if there are no more blocking senders, we also disable
639 * virtio's tx callbacks, to avoid the overhead incurred with handling
640 * those (now redundant) interrupts.
641 */
642static void rpmsg_downref_sleepers(struct virtproc_info *vrp)
643{
644 /* support multiple concurrent senders */
645 mutex_lock(&vrp->tx_lock);
646
647 /* are we the last sleeping context waiting for tx buffers ? */
648 if (atomic_dec_and_test(&vrp->sleepers))
649 /* disable "tx-complete" interrupts */
650 virtqueue_disable_cb(vrp->svq);
651
652 mutex_unlock(&vrp->tx_lock);
653}
654
655/**
656 * rpmsg_send_offchannel_raw() - send a message across to the remote processor
657 * @rpdev: the rpmsg channel
658 * @src: source address
659 * @dst: destination address
660 * @data: payload of message
661 * @len: length of payload
662 * @wait: indicates whether caller should block in case no TX buffers available
663 *
664 * This function is the base implementation for all of the rpmsg sending API.
665 *
666 * It will send @data of length @len to @dst, and say it's from @src. The
667 * message will be sent to the remote processor which the @rpdev channel
668 * belongs to.
669 *
670 * The message is sent using one of the TX buffers that are available for
671 * communication with this remote processor.
672 *
673 * If @wait is true, the caller will be blocked until either a TX buffer is
674 * available, or 15 seconds elapses (we don't want callers to
675 * sleep indefinitely due to misbehaving remote processors), and in that
676 * case -ERESTARTSYS is returned. The number '15' itself was picked
677 * arbitrarily; there's little point in asking drivers to provide a timeout
678 * value themselves.
679 *
680 * Otherwise, if @wait is false, and there are no TX buffers available,
681 * the function will immediately fail, and -ENOMEM will be returned.
682 *
683 * Normally drivers shouldn't use this function directly; instead, drivers
684 * should use the appropriate rpmsg_{try}send{to, _offchannel} API
685 * (see include/linux/rpmsg.h).
686 *
687 * Returns 0 on success and an appropriate error value on failure.
688 */
689int rpmsg_send_offchannel_raw(struct rpmsg_channel *rpdev, u32 src, u32 dst,
690 void *data, int len, bool wait)
691{
692 struct virtproc_info *vrp = rpdev->vrp;
693 struct device *dev = &rpdev->dev;
694 struct scatterlist sg;
695 struct rpmsg_hdr *msg;
696 int err;
697
698 /* bcasting isn't allowed */
699 if (src == RPMSG_ADDR_ANY || dst == RPMSG_ADDR_ANY) {
700 dev_err(dev, "invalid addr (src 0x%x, dst 0x%x)\n", src, dst);
701 return -EINVAL;
702 }
703
704 /*
705 * We currently use fixed-sized buffers, and therefore the payload
706 * length is limited.
707 *
708 * One of the possible improvements here is either to support
709 * user-provided buffers (and then we can also support zero-copy
710 * messaging), or to improve the buffer allocator, to support
711 * variable-length buffer sizes.
712 */
713 if (len > RPMSG_BUF_SIZE - sizeof(struct rpmsg_hdr)) {
714 dev_err(dev, "message is too big (%d)\n", len);
715 return -EMSGSIZE;
716 }
717
718 /* grab a buffer */
719 msg = get_a_tx_buf(vrp);
720 if (!msg && !wait)
721 return -ENOMEM;
722
723 /* no free buffer ? wait for one (but bail after 15 seconds) */
724 while (!msg) {
725 /* enable "tx-complete" interrupts, if not already enabled */
726 rpmsg_upref_sleepers(vrp);
727
728 /*
729 * sleep until a free buffer is available or 15 secs elapse.
730 * the timeout period is not configurable because there's
731 * little point in asking drivers to specify that.
732 * if later this happens to be required, it'd be easy to add.
733 */
734 err = wait_event_interruptible_timeout(vrp->sendq,
735 (msg = get_a_tx_buf(vrp)),
736 msecs_to_jiffies(15000));
737
738 /* disable "tx-complete" interrupts if we're the last sleeper */
739 rpmsg_downref_sleepers(vrp);
740
741 /* timeout ? */
742 if (!err) {
743 dev_err(dev, "timeout waiting for a tx buffer\n");
744 return -ERESTARTSYS;
745 }
746 }
747
748 msg->len = len;
749 msg->flags = 0;
750 msg->src = src;
751 msg->dst = dst;
752 msg->reserved = 0;
753 memcpy(msg->data, data, len);
754
755 dev_dbg(dev, "TX From 0x%x, To 0x%x, Len %d, Flags %d, Reserved %d\n",
756 msg->src, msg->dst, msg->len,
757 msg->flags, msg->reserved);
758 print_hex_dump(KERN_DEBUG, "rpmsg_virtio TX: ", DUMP_PREFIX_NONE, 16, 1,
759 msg, sizeof(*msg) + msg->len, true);
760
761 sg_init_one(&sg, msg, sizeof(*msg) + len);
762
763 mutex_lock(&vrp->tx_lock);
764
765 /* add message to the remote processor's virtqueue */
766 err = virtqueue_add_buf(vrp->svq, &sg, 1, 0, msg, GFP_KERNEL);
767 if (err < 0) {
768 /*
769 * need to reclaim the buffer here, otherwise it's lost
770 * (memory won't leak, but rpmsg won't use it again for TX).
771 * this will wait for a buffer management overhaul.
772 */
773 dev_err(dev, "virtqueue_add_buf failed: %d\n", err);
774 goto out;
775 }
776
777 /* tell the remote processor it has a pending message to read */
778 virtqueue_kick(vrp->svq);
779
780 err = 0;
781out:
782 mutex_unlock(&vrp->tx_lock);
783 return err;
784}
785EXPORT_SYMBOL(rpmsg_send_offchannel_raw);
786
787/* called when an rx buffer is used, and it's time to digest a message */
788static void rpmsg_recv_done(struct virtqueue *rvq)
789{
790 struct rpmsg_hdr *msg;
791 unsigned int len;
792 struct rpmsg_endpoint *ept;
793 struct scatterlist sg;
794 struct virtproc_info *vrp = rvq->vdev->priv;
795 struct device *dev = &rvq->vdev->dev;
796 int err;
797
798 msg = virtqueue_get_buf(rvq, &len);
799 if (!msg) {
800 dev_err(dev, "uhm, incoming signal, but no used buffer ?\n");
801 return;
802 }
803
804 dev_dbg(dev, "From: 0x%x, To: 0x%x, Len: %d, Flags: %d, Reserved: %d\n",
805 msg->src, msg->dst, msg->len,
806 msg->flags, msg->reserved);
807 print_hex_dump(KERN_DEBUG, "rpmsg_virtio RX: ", DUMP_PREFIX_NONE, 16, 1,
808 msg, sizeof(*msg) + msg->len, true);
809
810 /*
811 * We currently use fixed-sized buffers, so trivially sanitize
812 * the reported payload length.
813 */
814 if (len > RPMSG_BUF_SIZE ||
815 msg->len > (len - sizeof(struct rpmsg_hdr))) {
816 dev_warn(dev, "inbound msg too big: (%d, %d)\n", len, msg->len);
817 return;
818 }
819
820 /* use the dst addr to fetch the callback of the appropriate user */
821 mutex_lock(&vrp->endpoints_lock);
822
823 ept = idr_find(&vrp->endpoints, msg->dst);
824
825 /* let's make sure no one deallocates ept while we use it */
826 if (ept)
827 kref_get(&ept->refcount);
828
829 mutex_unlock(&vrp->endpoints_lock);
830
831 if (ept) {
832 /* make sure ept->cb doesn't go away while we use it */
833 mutex_lock(&ept->cb_lock);
834
835 if (ept->cb)
836 ept->cb(ept->rpdev, msg->data, msg->len, ept->priv,
837 msg->src);
838
839 mutex_unlock(&ept->cb_lock);
840
841 /* farewell, ept, we don't need you anymore */
842 kref_put(&ept->refcount, __ept_release);
843 } else
844 dev_warn(dev, "msg received with no recepient\n");
845
846 /* publish the real size of the buffer */
847 sg_init_one(&sg, msg, RPMSG_BUF_SIZE);
848
849 /* add the buffer back to the remote processor's virtqueue */
850 err = virtqueue_add_buf(vrp->rvq, &sg, 0, 1, msg, GFP_KERNEL);
851 if (err < 0) {
852 dev_err(dev, "failed to add a virtqueue buffer: %d\n", err);
853 return;
854 }
855
856 /* tell the remote processor we added another available rx buffer */
857 virtqueue_kick(vrp->rvq);
858}
859
860/*
861 * This is invoked whenever the remote processor completed processing
862 * a TX msg we just sent it, and the buffer is put back to the used ring.
863 *
864 * Normally, though, we suppress this "tx complete" interrupt in order to
865 * avoid the incurred overhead.
866 */
867static void rpmsg_xmit_done(struct virtqueue *svq)
868{
869 struct virtproc_info *vrp = svq->vdev->priv;
870
871 dev_dbg(&svq->vdev->dev, "%s\n", __func__);
872
873 /* wake up potential senders that are waiting for a tx buffer */
874 wake_up_interruptible(&vrp->sendq);
875}
876
877/* invoked when a name service announcement arrives */
878static void rpmsg_ns_cb(struct rpmsg_channel *rpdev, void *data, int len,
879 void *priv, u32 src)
880{
881 struct rpmsg_ns_msg *msg = data;
882 struct rpmsg_channel *newch;
883 struct rpmsg_channel_info chinfo;
884 struct virtproc_info *vrp = priv;
885 struct device *dev = &vrp->vdev->dev;
886 int ret;
887
888 print_hex_dump(KERN_DEBUG, "NS announcement: ",
889 DUMP_PREFIX_NONE, 16, 1,
890 data, len, true);
891
892 if (len != sizeof(*msg)) {
893 dev_err(dev, "malformed ns msg (%d)\n", len);
894 return;
895 }
896
897 /*
898 * the name service ept does _not_ belong to a real rpmsg channel,
899 * and is handled by the rpmsg bus itself.
900 * for sanity reasons, make sure a valid rpdev has _not_ sneaked
901 * in somehow.
902 */
903 if (rpdev) {
904 dev_err(dev, "anomaly: ns ept has an rpdev handle\n");
905 return;
906 }
907
908 /* don't trust the remote processor for null terminating the name */
909 msg->name[RPMSG_NAME_SIZE - 1] = '\0';
910
911 dev_info(dev, "%sing channel %s addr 0x%x\n",
912 msg->flags & RPMSG_NS_DESTROY ? "destroy" : "creat",
913 msg->name, msg->addr);
914
915 strncpy(chinfo.name, msg->name, sizeof(chinfo.name));
916 chinfo.src = RPMSG_ADDR_ANY;
917 chinfo.dst = msg->addr;
918
919 if (msg->flags & RPMSG_NS_DESTROY) {
920 ret = rpmsg_destroy_channel(vrp, &chinfo);
921 if (ret)
922 dev_err(dev, "rpmsg_destroy_channel failed: %d\n", ret);
923 } else {
924 newch = rpmsg_create_channel(vrp, &chinfo);
925 if (!newch)
926 dev_err(dev, "rpmsg_create_channel failed\n");
927 }
928}
929
930static int rpmsg_probe(struct virtio_device *vdev)
931{
932 vq_callback_t *vq_cbs[] = { rpmsg_recv_done, rpmsg_xmit_done };
933 const char *names[] = { "input", "output" };
934 struct virtqueue *vqs[2];
935 struct virtproc_info *vrp;
936 void *bufs_va;
937 int err = 0, i;
938
939 vrp = kzalloc(sizeof(*vrp), GFP_KERNEL);
940 if (!vrp)
941 return -ENOMEM;
942
943 vrp->vdev = vdev;
944
945 idr_init(&vrp->endpoints);
946 mutex_init(&vrp->endpoints_lock);
947 mutex_init(&vrp->tx_lock);
948 init_waitqueue_head(&vrp->sendq);
949
950 /* We expect two virtqueues, rx and tx (and in this order) */
951 err = vdev->config->find_vqs(vdev, 2, vqs, vq_cbs, names);
952 if (err)
953 goto free_vrp;
954
955 vrp->rvq = vqs[0];
956 vrp->svq = vqs[1];
957
958 /* allocate coherent memory for the buffers */
959 bufs_va = dma_alloc_coherent(vdev->dev.parent, RPMSG_TOTAL_BUF_SPACE,
960 &vrp->bufs_dma, GFP_KERNEL);
961 if (!bufs_va)
962 goto vqs_del;
963
964 dev_dbg(&vdev->dev, "buffers: va %p, dma 0x%llx\n", bufs_va,
965 (unsigned long long)vrp->bufs_dma);
966
967 /* half of the buffers is dedicated for RX */
968 vrp->rbufs = bufs_va;
969
970 /* and half is dedicated for TX */
971 vrp->sbufs = bufs_va + RPMSG_TOTAL_BUF_SPACE / 2;
972
973 /* set up the receive buffers */
974 for (i = 0; i < RPMSG_NUM_BUFS / 2; i++) {
975 struct scatterlist sg;
976 void *cpu_addr = vrp->rbufs + i * RPMSG_BUF_SIZE;
977
978 sg_init_one(&sg, cpu_addr, RPMSG_BUF_SIZE);
979
980 err = virtqueue_add_buf(vrp->rvq, &sg, 0, 1, cpu_addr,
981 GFP_KERNEL);
982 WARN_ON(err < 0); /* sanity check; this can't really happen */
983 }
984
985 /* suppress "tx-complete" interrupts */
986 virtqueue_disable_cb(vrp->svq);
987
988 vdev->priv = vrp;
989
990 /* if supported by the remote processor, enable the name service */
991 if (virtio_has_feature(vdev, VIRTIO_RPMSG_F_NS)) {
992 /* a dedicated endpoint handles the name service msgs */
993 vrp->ns_ept = __rpmsg_create_ept(vrp, NULL, rpmsg_ns_cb,
994 vrp, RPMSG_NS_ADDR);
995 if (!vrp->ns_ept) {
996 dev_err(&vdev->dev, "failed to create the ns ept\n");
997 err = -ENOMEM;
998 goto free_coherent;
999 }
1000 }
1001
1002 /* tell the remote processor it can start sending messages */
1003 virtqueue_kick(vrp->rvq);
1004
1005 dev_info(&vdev->dev, "rpmsg host is online\n");
1006
1007 return 0;
1008
1009free_coherent:
1010 dma_free_coherent(vdev->dev.parent, RPMSG_TOTAL_BUF_SPACE, bufs_va,
1011 vrp->bufs_dma);
1012vqs_del:
1013 vdev->config->del_vqs(vrp->vdev);
1014free_vrp:
1015 kfree(vrp);
1016 return err;
1017}
1018
1019static int rpmsg_remove_device(struct device *dev, void *data)
1020{
1021 device_unregister(dev);
1022
1023 return 0;
1024}
1025
1026static void __devexit rpmsg_remove(struct virtio_device *vdev)
1027{
1028 struct virtproc_info *vrp = vdev->priv;
1029 int ret;
1030
1031 vdev->config->reset(vdev);
1032
1033 ret = device_for_each_child(&vdev->dev, NULL, rpmsg_remove_device);
1034 if (ret)
1035 dev_warn(&vdev->dev, "can't remove rpmsg device: %d\n", ret);
1036
1037 if (vrp->ns_ept)
1038 __rpmsg_destroy_ept(vrp, vrp->ns_ept);
1039
1040 idr_remove_all(&vrp->endpoints);
1041 idr_destroy(&vrp->endpoints);
1042
1043 vdev->config->del_vqs(vrp->vdev);
1044
1045 dma_free_coherent(vdev->dev.parent, RPMSG_TOTAL_BUF_SPACE,
1046 vrp->rbufs, vrp->bufs_dma);
1047
1048 kfree(vrp);
1049}
1050
1051static struct virtio_device_id id_table[] = {
1052 { VIRTIO_ID_RPMSG, VIRTIO_DEV_ANY_ID },
1053 { 0 },
1054};
1055
1056static unsigned int features[] = {
1057 VIRTIO_RPMSG_F_NS,
1058};
1059
1060static struct virtio_driver virtio_ipc_driver = {
1061 .feature_table = features,
1062 .feature_table_size = ARRAY_SIZE(features),
1063 .driver.name = KBUILD_MODNAME,
1064 .driver.owner = THIS_MODULE,
1065 .id_table = id_table,
1066 .probe = rpmsg_probe,
1067 .remove = __devexit_p(rpmsg_remove),
1068};
1069
1070static int __init rpmsg_init(void)
1071{
1072 int ret;
1073
1074 ret = bus_register(&rpmsg_bus);
1075 if (ret) {
1076 pr_err("failed to register rpmsg bus: %d\n", ret);
1077 return ret;
1078 }
1079
1080 ret = register_virtio_driver(&virtio_ipc_driver);
1081 if (ret) {
1082 pr_err("failed to register virtio driver: %d\n", ret);
1083 bus_unregister(&rpmsg_bus);
1084 }
1085
1086 return ret;
1087}
1088subsys_initcall(rpmsg_init);
1089
1090static void __exit rpmsg_fini(void)
1091{
1092 unregister_virtio_driver(&virtio_ipc_driver);
1093 bus_unregister(&rpmsg_bus);
1094}
1095module_exit(rpmsg_fini);
1096
1097MODULE_DEVICE_TABLE(virtio, id_table);
1098MODULE_DESCRIPTION("Virtio-based remote processor messaging bus");
1099MODULE_LICENSE("GPL v2");