2 * Virtio-based remote processor messaging bus
4 * Copyright (C) 2011 Texas Instruments, Inc.
5 * Copyright (C) 2011 Google, Inc.
7 * Ohad Ben-Cohen <ohad@wizery.com>
8 * Brian Swetland <swetland@google.com>
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.
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.
20 #define pr_fmt(fmt) "%s: " fmt, __func__
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 #include <linux/of_device.h>
38 #include "rpmsg_internal.h"
41 * struct virtproc_info - virtual remote processor state
42 * @vdev: the virtio device
45 * @rbufs: kernel address of rx buffers
46 * @sbufs: kernel address of tx buffers
47 * @num_bufs: total number of buffers for rx and tx
48 * @last_sbuf: index of last tx buffer used
49 * @bufs_dma: dma base addr of the buffers
50 * @tx_lock: protects svq, sbufs and sleepers, to allow concurrent senders.
51 * sending a message might require waking up a dozing remote
52 * processor, which involves sleeping, hence the mutex.
53 * @endpoints: idr of local endpoints, allows fast retrieval
54 * @endpoints_lock: lock of the endpoints set
55 * @sendq: wait queue of sending contexts waiting for a tx buffers
56 * @sleepers: number of senders that are waiting for a tx buffer
57 * @ns_ept: the bus's name service endpoint
59 * This structure stores the rpmsg state of a given virtio remote processor
60 * device (there might be several virtio proc devices for each physical
63 struct virtproc_info {
64 struct virtio_device *vdev;
65 struct virtqueue *rvq, *svq;
67 unsigned int num_bufs;
72 struct mutex endpoints_lock;
73 wait_queue_head_t sendq;
75 struct rpmsg_endpoint *ns_ept;
78 /* The feature bitmap for virtio rpmsg */
79 #define VIRTIO_RPMSG_F_NS 0 /* RP supports name service notifications */
82 * struct rpmsg_hdr - common header for all rpmsg messages
83 * @src: source address
84 * @dst: destination address
85 * @reserved: reserved for future use
86 * @len: length of payload (in bytes)
87 * @flags: message flags
88 * @data: @len bytes of message payload data
90 * Every message sent(/received) on the rpmsg bus begins with this header.
102 * struct rpmsg_ns_msg - dynamic name service announcement message
103 * @name: name of remote service that is published
104 * @addr: address of remote service that is published
105 * @flags: indicates whether service is created or destroyed
107 * This message is sent across to publish a new service, or announce
108 * about its removal. When we receive these messages, an appropriate
109 * rpmsg channel (i.e device) is created/destroyed. In turn, the ->probe()
110 * or ->remove() handler of the appropriate rpmsg driver will be invoked
111 * (if/as-soon-as one is registered).
113 struct rpmsg_ns_msg {
114 char name[RPMSG_NAME_SIZE];
120 * enum rpmsg_ns_flags - dynamic name service announcement flags
122 * @RPMSG_NS_CREATE: a new remote service was just created
123 * @RPMSG_NS_DESTROY: a known remote service was just destroyed
125 enum rpmsg_ns_flags {
127 RPMSG_NS_DESTROY = 1,
131 * @vrp: the remote processor this channel belongs to
133 struct virtio_rpmsg_channel {
134 struct rpmsg_device rpdev;
136 struct virtproc_info *vrp;
139 #define to_virtio_rpmsg_channel(_rpdev) \
140 container_of(_rpdev, struct virtio_rpmsg_channel, rpdev)
143 * We're allocating buffers of 512 bytes each for communications. The
144 * number of buffers will be computed from the number of buffers supported
145 * by the vring, upto a maximum of 512 buffers (256 in each direction).
147 * Each buffer will have 16 bytes for the msg header and 496 bytes for
150 * This will utilize a maximum total space of 256KB for the buffers.
152 * We might also want to add support for user-provided buffers in time.
153 * This will allow bigger buffer size flexibility, and can also be used
154 * to achieve zero-copy messaging.
156 * Note that these numbers are purely a decision of this driver - we
157 * can change this without changing anything in the firmware of the remote
160 #define MAX_RPMSG_NUM_BUFS (512)
161 #define RPMSG_BUF_SIZE (512)
164 * Local addresses are dynamically allocated on-demand.
165 * We do not dynamically assign addresses from the low 1024 range,
166 * in order to reserve that address range for predefined services.
168 #define RPMSG_RESERVED_ADDRESSES (1024)
170 /* Address 53 is reserved for advertising remote services */
171 #define RPMSG_NS_ADDR (53)
173 static void virtio_rpmsg_destroy_ept(struct rpmsg_endpoint *ept);
174 static int virtio_rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len);
175 static int virtio_rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len,
177 static int virtio_rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src,
178 u32 dst, void *data, int len);
179 static int virtio_rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len);
180 static int virtio_rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data,
182 static int virtio_rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src,
183 u32 dst, void *data, int len);
185 static const struct rpmsg_endpoint_ops virtio_endpoint_ops = {
186 .destroy_ept = virtio_rpmsg_destroy_ept,
187 .send = virtio_rpmsg_send,
188 .sendto = virtio_rpmsg_sendto,
189 .send_offchannel = virtio_rpmsg_send_offchannel,
190 .trysend = virtio_rpmsg_trysend,
191 .trysendto = virtio_rpmsg_trysendto,
192 .trysend_offchannel = virtio_rpmsg_trysend_offchannel,
196 * __ept_release() - deallocate an rpmsg endpoint
197 * @kref: the ept's reference count
199 * This function deallocates an ept, and is invoked when its @kref refcount
202 * Never invoke this function directly!
204 static void __ept_release(struct kref *kref)
206 struct rpmsg_endpoint *ept = container_of(kref, struct rpmsg_endpoint,
209 * At this point no one holds a reference to ept anymore,
210 * so we can directly free it
215 /* for more info, see below documentation of rpmsg_create_ept() */
216 static struct rpmsg_endpoint *__rpmsg_create_ept(struct virtproc_info *vrp,
217 struct rpmsg_device *rpdev,
219 void *priv, u32 addr)
221 int id_min, id_max, id;
222 struct rpmsg_endpoint *ept;
223 struct device *dev = rpdev ? &rpdev->dev : &vrp->vdev->dev;
225 ept = kzalloc(sizeof(*ept), GFP_KERNEL);
229 kref_init(&ept->refcount);
230 mutex_init(&ept->cb_lock);
235 ept->ops = &virtio_endpoint_ops;
237 /* do we need to allocate a local address ? */
238 if (addr == RPMSG_ADDR_ANY) {
239 id_min = RPMSG_RESERVED_ADDRESSES;
246 mutex_lock(&vrp->endpoints_lock);
248 /* bind the endpoint to an rpmsg address (and allocate one if needed) */
249 id = idr_alloc(&vrp->endpoints, ept, id_min, id_max, GFP_KERNEL);
251 dev_err(dev, "idr_alloc failed: %d\n", id);
256 mutex_unlock(&vrp->endpoints_lock);
261 mutex_unlock(&vrp->endpoints_lock);
262 kref_put(&ept->refcount, __ept_release);
266 static struct rpmsg_endpoint *virtio_rpmsg_create_ept(struct rpmsg_device *rpdev,
269 struct rpmsg_channel_info chinfo)
271 struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev);
273 return __rpmsg_create_ept(vch->vrp, rpdev, cb, priv, chinfo.src);
277 * __rpmsg_destroy_ept() - destroy an existing rpmsg endpoint
278 * @vrp: virtproc which owns this ept
279 * @ept: endpoing to destroy
281 * An internal function which destroy an ept without assuming it is
282 * bound to an rpmsg channel. This is needed for handling the internal
283 * name service endpoint, which isn't bound to an rpmsg channel.
284 * See also __rpmsg_create_ept().
287 __rpmsg_destroy_ept(struct virtproc_info *vrp, struct rpmsg_endpoint *ept)
289 /* make sure new inbound messages can't find this ept anymore */
290 mutex_lock(&vrp->endpoints_lock);
291 idr_remove(&vrp->endpoints, ept->addr);
292 mutex_unlock(&vrp->endpoints_lock);
294 /* make sure in-flight inbound messages won't invoke cb anymore */
295 mutex_lock(&ept->cb_lock);
297 mutex_unlock(&ept->cb_lock);
299 kref_put(&ept->refcount, __ept_release);
302 static void virtio_rpmsg_destroy_ept(struct rpmsg_endpoint *ept)
304 struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(ept->rpdev);
306 __rpmsg_destroy_ept(vch->vrp, ept);
309 static int virtio_rpmsg_announce_create(struct rpmsg_device *rpdev)
311 struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev);
312 struct virtproc_info *vrp = vch->vrp;
313 struct device *dev = &rpdev->dev;
316 /* need to tell remote processor's name service about this channel ? */
317 if (rpdev->announce && rpdev->ept &&
318 virtio_has_feature(vrp->vdev, VIRTIO_RPMSG_F_NS)) {
319 struct rpmsg_ns_msg nsm;
321 strncpy(nsm.name, rpdev->id.name, RPMSG_NAME_SIZE);
322 nsm.addr = rpdev->ept->addr;
323 nsm.flags = RPMSG_NS_CREATE;
325 err = rpmsg_sendto(rpdev->ept, &nsm, sizeof(nsm), RPMSG_NS_ADDR);
327 dev_err(dev, "failed to announce service %d\n", err);
333 static int virtio_rpmsg_announce_destroy(struct rpmsg_device *rpdev)
335 struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev);
336 struct virtproc_info *vrp = vch->vrp;
337 struct device *dev = &rpdev->dev;
340 /* tell remote processor's name service we're removing this channel */
341 if (rpdev->announce && rpdev->ept &&
342 virtio_has_feature(vrp->vdev, VIRTIO_RPMSG_F_NS)) {
343 struct rpmsg_ns_msg nsm;
345 strncpy(nsm.name, rpdev->id.name, RPMSG_NAME_SIZE);
346 nsm.addr = rpdev->ept->addr;
347 nsm.flags = RPMSG_NS_DESTROY;
349 err = rpmsg_sendto(rpdev->ept, &nsm, sizeof(nsm), RPMSG_NS_ADDR);
351 dev_err(dev, "failed to announce service %d\n", err);
357 static const struct rpmsg_device_ops virtio_rpmsg_ops = {
358 .create_ept = virtio_rpmsg_create_ept,
359 .announce_create = virtio_rpmsg_announce_create,
360 .announce_destroy = virtio_rpmsg_announce_destroy,
363 static void virtio_rpmsg_release_device(struct device *dev)
365 struct rpmsg_device *rpdev = to_rpmsg_device(dev);
366 struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev);
372 * create an rpmsg channel using its name and address info.
373 * this function will be used to create both static and dynamic
376 static struct rpmsg_device *rpmsg_create_channel(struct virtproc_info *vrp,
377 struct rpmsg_channel_info *chinfo)
379 struct virtio_rpmsg_channel *vch;
380 struct rpmsg_device *rpdev;
381 struct device *tmp, *dev = &vrp->vdev->dev;
384 /* make sure a similar channel doesn't already exist */
385 tmp = rpmsg_find_device(dev, chinfo);
387 /* decrement the matched device's refcount back */
389 dev_err(dev, "channel %s:%x:%x already exist\n",
390 chinfo->name, chinfo->src, chinfo->dst);
394 vch = kzalloc(sizeof(*vch), GFP_KERNEL);
398 /* Link the channel to our vrp */
401 /* Assign public information to the rpmsg_device */
403 rpdev->src = chinfo->src;
404 rpdev->dst = chinfo->dst;
405 rpdev->ops = &virtio_rpmsg_ops;
408 * rpmsg server channels has predefined local address (for now),
409 * and their existence needs to be announced remotely
411 rpdev->announce = rpdev->src != RPMSG_ADDR_ANY;
413 strncpy(rpdev->id.name, chinfo->name, RPMSG_NAME_SIZE);
415 rpdev->dev.parent = &vrp->vdev->dev;
416 rpdev->dev.release = virtio_rpmsg_release_device;
417 ret = rpmsg_register_device(rpdev);
424 /* super simple buffer "allocator" that is just enough for now */
425 static void *get_a_tx_buf(struct virtproc_info *vrp)
430 /* support multiple concurrent senders */
431 mutex_lock(&vrp->tx_lock);
434 * either pick the next unused tx buffer
435 * (half of our buffers are used for sending messages)
437 if (vrp->last_sbuf < vrp->num_bufs / 2)
438 ret = vrp->sbufs + RPMSG_BUF_SIZE * vrp->last_sbuf++;
439 /* or recycle a used one */
441 ret = virtqueue_get_buf(vrp->svq, &len);
443 mutex_unlock(&vrp->tx_lock);
449 * rpmsg_upref_sleepers() - enable "tx-complete" interrupts, if needed
450 * @vrp: virtual remote processor state
452 * This function is called before a sender is blocked, waiting for
453 * a tx buffer to become available.
455 * If we already have blocking senders, this function merely increases
456 * the "sleepers" reference count, and exits.
458 * Otherwise, if this is the first sender to block, we also enable
459 * virtio's tx callbacks, so we'd be immediately notified when a tx
460 * buffer is consumed (we rely on virtio's tx callback in order
461 * to wake up sleeping senders as soon as a tx buffer is used by the
464 static void rpmsg_upref_sleepers(struct virtproc_info *vrp)
466 /* support multiple concurrent senders */
467 mutex_lock(&vrp->tx_lock);
469 /* are we the first sleeping context waiting for tx buffers ? */
470 if (atomic_inc_return(&vrp->sleepers) == 1)
471 /* enable "tx-complete" interrupts before dozing off */
472 virtqueue_enable_cb(vrp->svq);
474 mutex_unlock(&vrp->tx_lock);
478 * rpmsg_downref_sleepers() - disable "tx-complete" interrupts, if needed
479 * @vrp: virtual remote processor state
481 * This function is called after a sender, that waited for a tx buffer
482 * to become available, is unblocked.
484 * If we still have blocking senders, this function merely decreases
485 * the "sleepers" reference count, and exits.
487 * Otherwise, if there are no more blocking senders, we also disable
488 * virtio's tx callbacks, to avoid the overhead incurred with handling
489 * those (now redundant) interrupts.
491 static void rpmsg_downref_sleepers(struct virtproc_info *vrp)
493 /* support multiple concurrent senders */
494 mutex_lock(&vrp->tx_lock);
496 /* are we the last sleeping context waiting for tx buffers ? */
497 if (atomic_dec_and_test(&vrp->sleepers))
498 /* disable "tx-complete" interrupts */
499 virtqueue_disable_cb(vrp->svq);
501 mutex_unlock(&vrp->tx_lock);
505 * rpmsg_send_offchannel_raw() - send a message across to the remote processor
506 * @rpdev: the rpmsg channel
507 * @src: source address
508 * @dst: destination address
509 * @data: payload of message
510 * @len: length of payload
511 * @wait: indicates whether caller should block in case no TX buffers available
513 * This function is the base implementation for all of the rpmsg sending API.
515 * It will send @data of length @len to @dst, and say it's from @src. The
516 * message will be sent to the remote processor which the @rpdev channel
519 * The message is sent using one of the TX buffers that are available for
520 * communication with this remote processor.
522 * If @wait is true, the caller will be blocked until either a TX buffer is
523 * available, or 15 seconds elapses (we don't want callers to
524 * sleep indefinitely due to misbehaving remote processors), and in that
525 * case -ERESTARTSYS is returned. The number '15' itself was picked
526 * arbitrarily; there's little point in asking drivers to provide a timeout
529 * Otherwise, if @wait is false, and there are no TX buffers available,
530 * the function will immediately fail, and -ENOMEM will be returned.
532 * Normally drivers shouldn't use this function directly; instead, drivers
533 * should use the appropriate rpmsg_{try}send{to, _offchannel} API
534 * (see include/linux/rpmsg.h).
536 * Returns 0 on success and an appropriate error value on failure.
538 static int rpmsg_send_offchannel_raw(struct rpmsg_device *rpdev,
540 void *data, int len, bool wait)
542 struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev);
543 struct virtproc_info *vrp = vch->vrp;
544 struct device *dev = &rpdev->dev;
545 struct scatterlist sg;
546 struct rpmsg_hdr *msg;
549 /* bcasting isn't allowed */
550 if (src == RPMSG_ADDR_ANY || dst == RPMSG_ADDR_ANY) {
551 dev_err(dev, "invalid addr (src 0x%x, dst 0x%x)\n", src, dst);
556 * We currently use fixed-sized buffers, and therefore the payload
559 * One of the possible improvements here is either to support
560 * user-provided buffers (and then we can also support zero-copy
561 * messaging), or to improve the buffer allocator, to support
562 * variable-length buffer sizes.
564 if (len > RPMSG_BUF_SIZE - sizeof(struct rpmsg_hdr)) {
565 dev_err(dev, "message is too big (%d)\n", len);
570 msg = get_a_tx_buf(vrp);
574 /* no free buffer ? wait for one (but bail after 15 seconds) */
576 /* enable "tx-complete" interrupts, if not already enabled */
577 rpmsg_upref_sleepers(vrp);
580 * sleep until a free buffer is available or 15 secs elapse.
581 * the timeout period is not configurable because there's
582 * little point in asking drivers to specify that.
583 * if later this happens to be required, it'd be easy to add.
585 err = wait_event_interruptible_timeout(vrp->sendq,
586 (msg = get_a_tx_buf(vrp)),
587 msecs_to_jiffies(15000));
589 /* disable "tx-complete" interrupts if we're the last sleeper */
590 rpmsg_downref_sleepers(vrp);
594 dev_err(dev, "timeout waiting for a tx buffer\n");
604 memcpy(msg->data, data, len);
606 dev_dbg(dev, "TX From 0x%x, To 0x%x, Len %d, Flags %d, Reserved %d\n",
607 msg->src, msg->dst, msg->len, msg->flags, msg->reserved);
608 #if defined(CONFIG_DYNAMIC_DEBUG)
609 dynamic_hex_dump("rpmsg_virtio TX: ", DUMP_PREFIX_NONE, 16, 1,
610 msg, sizeof(*msg) + msg->len, true);
613 sg_init_one(&sg, msg, sizeof(*msg) + len);
615 mutex_lock(&vrp->tx_lock);
617 /* add message to the remote processor's virtqueue */
618 err = virtqueue_add_outbuf(vrp->svq, &sg, 1, msg, GFP_KERNEL);
621 * need to reclaim the buffer here, otherwise it's lost
622 * (memory won't leak, but rpmsg won't use it again for TX).
623 * this will wait for a buffer management overhaul.
625 dev_err(dev, "virtqueue_add_outbuf failed: %d\n", err);
629 /* tell the remote processor it has a pending message to read */
630 virtqueue_kick(vrp->svq);
632 mutex_unlock(&vrp->tx_lock);
635 EXPORT_SYMBOL(rpmsg_send_offchannel_raw);
637 static int virtio_rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len)
639 struct rpmsg_device *rpdev = ept->rpdev;
640 u32 src = ept->addr, dst = rpdev->dst;
642 return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
645 static int virtio_rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len,
648 struct rpmsg_device *rpdev = ept->rpdev;
651 return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
654 static int virtio_rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src,
655 u32 dst, void *data, int len)
657 struct rpmsg_device *rpdev = ept->rpdev;
659 return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
662 static int virtio_rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len)
664 struct rpmsg_device *rpdev = ept->rpdev;
665 u32 src = ept->addr, dst = rpdev->dst;
667 return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
670 static int virtio_rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data,
673 struct rpmsg_device *rpdev = ept->rpdev;
676 return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
679 static int virtio_rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src,
680 u32 dst, void *data, int len)
682 struct rpmsg_device *rpdev = ept->rpdev;
684 return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
687 static int rpmsg_recv_single(struct virtproc_info *vrp, struct device *dev,
688 struct rpmsg_hdr *msg, unsigned int len)
690 struct rpmsg_endpoint *ept;
691 struct scatterlist sg;
694 dev_dbg(dev, "From: 0x%x, To: 0x%x, Len: %d, Flags: %d, Reserved: %d\n",
695 msg->src, msg->dst, msg->len, msg->flags, msg->reserved);
696 #if defined(CONFIG_DYNAMIC_DEBUG)
697 dynamic_hex_dump("rpmsg_virtio RX: ", DUMP_PREFIX_NONE, 16, 1,
698 msg, sizeof(*msg) + msg->len, true);
702 * We currently use fixed-sized buffers, so trivially sanitize
703 * the reported payload length.
705 if (len > RPMSG_BUF_SIZE ||
706 msg->len > (len - sizeof(struct rpmsg_hdr))) {
707 dev_warn(dev, "inbound msg too big: (%d, %d)\n", len, msg->len);
711 /* use the dst addr to fetch the callback of the appropriate user */
712 mutex_lock(&vrp->endpoints_lock);
714 ept = idr_find(&vrp->endpoints, msg->dst);
716 /* let's make sure no one deallocates ept while we use it */
718 kref_get(&ept->refcount);
720 mutex_unlock(&vrp->endpoints_lock);
723 /* make sure ept->cb doesn't go away while we use it */
724 mutex_lock(&ept->cb_lock);
727 ept->cb(ept->rpdev, msg->data, msg->len, ept->priv,
730 mutex_unlock(&ept->cb_lock);
732 /* farewell, ept, we don't need you anymore */
733 kref_put(&ept->refcount, __ept_release);
735 dev_warn(dev, "msg received with no recipient\n");
737 /* publish the real size of the buffer */
738 sg_init_one(&sg, msg, RPMSG_BUF_SIZE);
740 /* add the buffer back to the remote processor's virtqueue */
741 err = virtqueue_add_inbuf(vrp->rvq, &sg, 1, msg, GFP_KERNEL);
743 dev_err(dev, "failed to add a virtqueue buffer: %d\n", err);
750 /* called when an rx buffer is used, and it's time to digest a message */
751 static void rpmsg_recv_done(struct virtqueue *rvq)
753 struct virtproc_info *vrp = rvq->vdev->priv;
754 struct device *dev = &rvq->vdev->dev;
755 struct rpmsg_hdr *msg;
756 unsigned int len, msgs_received = 0;
759 msg = virtqueue_get_buf(rvq, &len);
761 dev_err(dev, "uhm, incoming signal, but no used buffer ?\n");
766 err = rpmsg_recv_single(vrp, dev, msg, len);
772 msg = virtqueue_get_buf(rvq, &len);
775 dev_dbg(dev, "Received %u messages\n", msgs_received);
777 /* tell the remote processor we added another available rx buffer */
779 virtqueue_kick(vrp->rvq);
783 * This is invoked whenever the remote processor completed processing
784 * a TX msg we just sent it, and the buffer is put back to the used ring.
786 * Normally, though, we suppress this "tx complete" interrupt in order to
787 * avoid the incurred overhead.
789 static void rpmsg_xmit_done(struct virtqueue *svq)
791 struct virtproc_info *vrp = svq->vdev->priv;
793 dev_dbg(&svq->vdev->dev, "%s\n", __func__);
795 /* wake up potential senders that are waiting for a tx buffer */
796 wake_up_interruptible(&vrp->sendq);
799 /* invoked when a name service announcement arrives */
800 static int rpmsg_ns_cb(struct rpmsg_device *rpdev, void *data, int len,
803 struct rpmsg_ns_msg *msg = data;
804 struct rpmsg_device *newch;
805 struct rpmsg_channel_info chinfo;
806 struct virtproc_info *vrp = priv;
807 struct device *dev = &vrp->vdev->dev;
810 #if defined(CONFIG_DYNAMIC_DEBUG)
811 dynamic_hex_dump("NS announcement: ", DUMP_PREFIX_NONE, 16, 1,
815 if (len != sizeof(*msg)) {
816 dev_err(dev, "malformed ns msg (%d)\n", len);
821 * the name service ept does _not_ belong to a real rpmsg channel,
822 * and is handled by the rpmsg bus itself.
823 * for sanity reasons, make sure a valid rpdev has _not_ sneaked
827 dev_err(dev, "anomaly: ns ept has an rpdev handle\n");
831 /* don't trust the remote processor for null terminating the name */
832 msg->name[RPMSG_NAME_SIZE - 1] = '\0';
834 dev_info(dev, "%sing channel %s addr 0x%x\n",
835 msg->flags & RPMSG_NS_DESTROY ? "destroy" : "creat",
836 msg->name, msg->addr);
838 strncpy(chinfo.name, msg->name, sizeof(chinfo.name));
839 chinfo.src = RPMSG_ADDR_ANY;
840 chinfo.dst = msg->addr;
842 if (msg->flags & RPMSG_NS_DESTROY) {
843 ret = rpmsg_unregister_device(&vrp->vdev->dev, &chinfo);
845 dev_err(dev, "rpmsg_destroy_channel failed: %d\n", ret);
847 newch = rpmsg_create_channel(vrp, &chinfo);
849 dev_err(dev, "rpmsg_create_channel failed\n");
855 static int rpmsg_probe(struct virtio_device *vdev)
857 vq_callback_t *vq_cbs[] = { rpmsg_recv_done, rpmsg_xmit_done };
858 static const char * const names[] = { "input", "output" };
859 struct virtqueue *vqs[2];
860 struct virtproc_info *vrp;
863 size_t total_buf_space;
866 vrp = kzalloc(sizeof(*vrp), GFP_KERNEL);
872 idr_init(&vrp->endpoints);
873 mutex_init(&vrp->endpoints_lock);
874 mutex_init(&vrp->tx_lock);
875 init_waitqueue_head(&vrp->sendq);
877 /* We expect two virtqueues, rx and tx (and in this order) */
878 err = virtio_find_vqs(vdev, 2, vqs, vq_cbs, names, NULL);
885 /* we expect symmetric tx/rx vrings */
886 WARN_ON(virtqueue_get_vring_size(vrp->rvq) !=
887 virtqueue_get_vring_size(vrp->svq));
889 /* we need less buffers if vrings are small */
890 if (virtqueue_get_vring_size(vrp->rvq) < MAX_RPMSG_NUM_BUFS / 2)
891 vrp->num_bufs = virtqueue_get_vring_size(vrp->rvq) * 2;
893 vrp->num_bufs = MAX_RPMSG_NUM_BUFS;
895 total_buf_space = vrp->num_bufs * RPMSG_BUF_SIZE;
897 /* allocate coherent memory for the buffers */
898 bufs_va = dma_alloc_coherent(vdev->dev.parent->parent,
899 total_buf_space, &vrp->bufs_dma,
906 dev_dbg(&vdev->dev, "buffers: va %p, dma %pad\n",
907 bufs_va, &vrp->bufs_dma);
909 /* half of the buffers is dedicated for RX */
910 vrp->rbufs = bufs_va;
912 /* and half is dedicated for TX */
913 vrp->sbufs = bufs_va + total_buf_space / 2;
915 /* set up the receive buffers */
916 for (i = 0; i < vrp->num_bufs / 2; i++) {
917 struct scatterlist sg;
918 void *cpu_addr = vrp->rbufs + i * RPMSG_BUF_SIZE;
920 sg_init_one(&sg, cpu_addr, RPMSG_BUF_SIZE);
922 err = virtqueue_add_inbuf(vrp->rvq, &sg, 1, cpu_addr,
924 WARN_ON(err); /* sanity check; this can't really happen */
927 /* suppress "tx-complete" interrupts */
928 virtqueue_disable_cb(vrp->svq);
932 /* if supported by the remote processor, enable the name service */
933 if (virtio_has_feature(vdev, VIRTIO_RPMSG_F_NS)) {
934 /* a dedicated endpoint handles the name service msgs */
935 vrp->ns_ept = __rpmsg_create_ept(vrp, NULL, rpmsg_ns_cb,
938 dev_err(&vdev->dev, "failed to create the ns ept\n");
945 * Prepare to kick but don't notify yet - we can't do this before
948 notify = virtqueue_kick_prepare(vrp->rvq);
950 /* From this point on, we can notify and get callbacks. */
951 virtio_device_ready(vdev);
953 /* tell the remote processor it can start sending messages */
955 * this might be concurrent with callbacks, but we are only
956 * doing notify, not a full kick here, so that's ok.
959 virtqueue_notify(vrp->rvq);
961 dev_info(&vdev->dev, "rpmsg host is online\n");
966 dma_free_coherent(vdev->dev.parent->parent, total_buf_space,
967 bufs_va, vrp->bufs_dma);
969 vdev->config->del_vqs(vrp->vdev);
975 static int rpmsg_remove_device(struct device *dev, void *data)
977 device_unregister(dev);
982 static void rpmsg_remove(struct virtio_device *vdev)
984 struct virtproc_info *vrp = vdev->priv;
985 size_t total_buf_space = vrp->num_bufs * RPMSG_BUF_SIZE;
988 vdev->config->reset(vdev);
990 ret = device_for_each_child(&vdev->dev, NULL, rpmsg_remove_device);
992 dev_warn(&vdev->dev, "can't remove rpmsg device: %d\n", ret);
995 __rpmsg_destroy_ept(vrp, vrp->ns_ept);
997 idr_destroy(&vrp->endpoints);
999 vdev->config->del_vqs(vrp->vdev);
1001 dma_free_coherent(vdev->dev.parent->parent, total_buf_space,
1002 vrp->rbufs, vrp->bufs_dma);
1007 static struct virtio_device_id id_table[] = {
1008 { VIRTIO_ID_RPMSG, VIRTIO_DEV_ANY_ID },
1012 static unsigned int features[] = {
1016 static struct virtio_driver virtio_ipc_driver = {
1017 .feature_table = features,
1018 .feature_table_size = ARRAY_SIZE(features),
1019 .driver.name = KBUILD_MODNAME,
1020 .driver.owner = THIS_MODULE,
1021 .id_table = id_table,
1022 .probe = rpmsg_probe,
1023 .remove = rpmsg_remove,
1026 static int __init rpmsg_init(void)
1030 ret = register_virtio_driver(&virtio_ipc_driver);
1032 pr_err("failed to register virtio driver: %d\n", ret);
1036 subsys_initcall(rpmsg_init);
1038 static void __exit rpmsg_fini(void)
1040 unregister_virtio_driver(&virtio_ipc_driver);
1042 module_exit(rpmsg_fini);
1044 MODULE_DEVICE_TABLE(virtio, id_table);
1045 MODULE_DESCRIPTION("Virtio-based remote processor messaging bus");
1046 MODULE_LICENSE("GPL v2");