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");