1 // SPDX-License-Identifier: GPL-2.0
3 * Virtio-based remote processor messaging bus
5 * Copyright (C) 2011 Texas Instruments, Inc.
6 * Copyright (C) 2011 Google, Inc.
8 * Ohad Ben-Cohen <ohad@wizery.com>
9 * Brian Swetland <swetland@google.com>
12 #define pr_fmt(fmt) "%s: " fmt, __func__
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/of_device.h>
21 #include <linux/rpmsg.h>
22 #include <linux/rpmsg/byteorder.h>
23 #include <linux/rpmsg/ns.h>
24 #include <linux/scatterlist.h>
25 #include <linux/slab.h>
26 #include <linux/sched.h>
27 #include <linux/virtio.h>
28 #include <linux/virtio_ids.h>
29 #include <linux/virtio_config.h>
30 #include <linux/wait.h>
32 #include "rpmsg_internal.h"
35 * struct virtproc_info - virtual remote processor state
36 * @vdev: the virtio device
39 * @rbufs: kernel address of rx buffers
40 * @sbufs: kernel address of tx buffers
41 * @num_bufs: total number of buffers for rx and tx
42 * @buf_size: size of one rx or tx buffer
43 * @last_sbuf: index of last tx buffer used
44 * @bufs_dma: dma base addr of the buffers
45 * @tx_lock: protects svq, sbufs and sleepers, to allow concurrent senders.
46 * sending a message might require waking up a dozing remote
47 * processor, which involves sleeping, hence the mutex.
48 * @endpoints: idr of local endpoints, allows fast retrieval
49 * @endpoints_lock: lock of the endpoints set
50 * @sendq: wait queue of sending contexts waiting for a tx buffers
51 * @sleepers: number of senders that are waiting for a tx buffer
53 * This structure stores the rpmsg state of a given virtio remote processor
54 * device (there might be several virtio proc devices for each physical
57 struct virtproc_info
{
58 struct virtio_device
*vdev
;
59 struct virtqueue
*rvq
, *svq
;
61 unsigned int num_bufs
;
62 unsigned int buf_size
;
67 struct mutex endpoints_lock
;
68 wait_queue_head_t sendq
;
72 /* The feature bitmap for virtio rpmsg */
73 #define VIRTIO_RPMSG_F_NS 0 /* RP supports name service notifications */
76 * struct rpmsg_hdr - common header for all rpmsg messages
77 * @src: source address
78 * @dst: destination address
79 * @reserved: reserved for future use
80 * @len: length of payload (in bytes)
81 * @flags: message flags
82 * @data: @len bytes of message payload data
84 * Every message sent(/received) on the rpmsg bus begins with this header.
97 * struct virtio_rpmsg_channel - rpmsg channel descriptor
98 * @rpdev: the rpmsg channel device
99 * @vrp: the virtio remote processor device this channel belongs to
101 * This structure stores the channel that links the rpmsg device to the virtio
102 * remote processor device.
104 struct virtio_rpmsg_channel
{
105 struct rpmsg_device rpdev
;
107 struct virtproc_info
*vrp
;
110 #define to_virtio_rpmsg_channel(_rpdev) \
111 container_of(_rpdev, struct virtio_rpmsg_channel, rpdev)
114 * We're allocating buffers of 512 bytes each for communications. The
115 * number of buffers will be computed from the number of buffers supported
116 * by the vring, upto a maximum of 512 buffers (256 in each direction).
118 * Each buffer will have 16 bytes for the msg header and 496 bytes for
121 * This will utilize a maximum total space of 256KB for the buffers.
123 * We might also want to add support for user-provided buffers in time.
124 * This will allow bigger buffer size flexibility, and can also be used
125 * to achieve zero-copy messaging.
127 * Note that these numbers are purely a decision of this driver - we
128 * can change this without changing anything in the firmware of the remote
131 #define MAX_RPMSG_NUM_BUFS (512)
132 #define MAX_RPMSG_BUF_SIZE (512)
135 * Local addresses are dynamically allocated on-demand.
136 * We do not dynamically assign addresses from the low 1024 range,
137 * in order to reserve that address range for predefined services.
139 #define RPMSG_RESERVED_ADDRESSES (1024)
141 static void virtio_rpmsg_destroy_ept(struct rpmsg_endpoint
*ept
);
142 static int virtio_rpmsg_send(struct rpmsg_endpoint
*ept
, void *data
, int len
);
143 static int virtio_rpmsg_sendto(struct rpmsg_endpoint
*ept
, void *data
, int len
,
145 static int virtio_rpmsg_send_offchannel(struct rpmsg_endpoint
*ept
, u32 src
,
146 u32 dst
, void *data
, int len
);
147 static int virtio_rpmsg_trysend(struct rpmsg_endpoint
*ept
, void *data
, int len
);
148 static int virtio_rpmsg_trysendto(struct rpmsg_endpoint
*ept
, void *data
,
150 static int virtio_rpmsg_trysend_offchannel(struct rpmsg_endpoint
*ept
, u32 src
,
151 u32 dst
, void *data
, int len
);
152 static struct rpmsg_device
*__rpmsg_create_channel(struct virtproc_info
*vrp
,
153 struct rpmsg_channel_info
*chinfo
);
155 static 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
,
166 * rpmsg_sg_init - initialize scatterlist according to cpu address location
167 * @sg: scatterlist to fill
168 * @cpu_addr: virtual address of the buffer
169 * @len: buffer length
171 * An internal function filling scatterlist according to virtual address
172 * location (in vmalloc or in kernel).
175 rpmsg_sg_init(struct scatterlist
*sg
, void *cpu_addr
, unsigned int len
)
177 if (is_vmalloc_addr(cpu_addr
)) {
178 sg_init_table(sg
, 1);
179 sg_set_page(sg
, vmalloc_to_page(cpu_addr
), len
,
180 offset_in_page(cpu_addr
));
182 WARN_ON(!virt_addr_valid(cpu_addr
));
183 sg_init_one(sg
, cpu_addr
, len
);
188 * __ept_release() - deallocate an rpmsg endpoint
189 * @kref: the ept's reference count
191 * This function deallocates an ept, and is invoked when its @kref refcount
194 * Never invoke this function directly!
196 static void __ept_release(struct kref
*kref
)
198 struct rpmsg_endpoint
*ept
= container_of(kref
, struct rpmsg_endpoint
,
201 * At this point no one holds a reference to ept anymore,
202 * so we can directly free it
207 /* for more info, see below documentation of rpmsg_create_ept() */
208 static struct rpmsg_endpoint
*__rpmsg_create_ept(struct virtproc_info
*vrp
,
209 struct rpmsg_device
*rpdev
,
211 void *priv
, u32 addr
)
213 int id_min
, id_max
, id
;
214 struct rpmsg_endpoint
*ept
;
215 struct device
*dev
= rpdev
? &rpdev
->dev
: &vrp
->vdev
->dev
;
217 ept
= kzalloc(sizeof(*ept
), GFP_KERNEL
);
221 kref_init(&ept
->refcount
);
222 mutex_init(&ept
->cb_lock
);
227 ept
->ops
= &virtio_endpoint_ops
;
229 /* do we need to allocate a local address ? */
230 if (addr
== RPMSG_ADDR_ANY
) {
231 id_min
= RPMSG_RESERVED_ADDRESSES
;
238 mutex_lock(&vrp
->endpoints_lock
);
240 /* bind the endpoint to an rpmsg address (and allocate one if needed) */
241 id
= idr_alloc(&vrp
->endpoints
, ept
, id_min
, id_max
, GFP_KERNEL
);
243 dev_err(dev
, "idr_alloc failed: %d\n", id
);
248 mutex_unlock(&vrp
->endpoints_lock
);
253 mutex_unlock(&vrp
->endpoints_lock
);
254 kref_put(&ept
->refcount
, __ept_release
);
258 static struct rpmsg_device
*virtio_rpmsg_create_channel(struct rpmsg_device
*rpdev
,
259 struct rpmsg_channel_info
*chinfo
)
261 struct virtio_rpmsg_channel
*vch
= to_virtio_rpmsg_channel(rpdev
);
262 struct virtproc_info
*vrp
= vch
->vrp
;
264 return __rpmsg_create_channel(vrp
, chinfo
);
267 static int virtio_rpmsg_release_channel(struct rpmsg_device
*rpdev
,
268 struct rpmsg_channel_info
*chinfo
)
270 struct virtio_rpmsg_channel
*vch
= to_virtio_rpmsg_channel(rpdev
);
271 struct virtproc_info
*vrp
= vch
->vrp
;
273 return rpmsg_unregister_device(&vrp
->vdev
->dev
, chinfo
);
276 static struct rpmsg_endpoint
*virtio_rpmsg_create_ept(struct rpmsg_device
*rpdev
,
279 struct rpmsg_channel_info chinfo
)
281 struct virtio_rpmsg_channel
*vch
= to_virtio_rpmsg_channel(rpdev
);
283 return __rpmsg_create_ept(vch
->vrp
, rpdev
, cb
, priv
, chinfo
.src
);
287 * __rpmsg_destroy_ept() - destroy an existing rpmsg endpoint
288 * @vrp: virtproc which owns this ept
289 * @ept: endpoing to destroy
291 * An internal function which destroy an ept without assuming it is
292 * bound to an rpmsg channel. This is needed for handling the internal
293 * name service endpoint, which isn't bound to an rpmsg channel.
294 * See also __rpmsg_create_ept().
297 __rpmsg_destroy_ept(struct virtproc_info
*vrp
, struct rpmsg_endpoint
*ept
)
299 /* make sure new inbound messages can't find this ept anymore */
300 mutex_lock(&vrp
->endpoints_lock
);
301 idr_remove(&vrp
->endpoints
, ept
->addr
);
302 mutex_unlock(&vrp
->endpoints_lock
);
304 /* make sure in-flight inbound messages won't invoke cb anymore */
305 mutex_lock(&ept
->cb_lock
);
307 mutex_unlock(&ept
->cb_lock
);
309 kref_put(&ept
->refcount
, __ept_release
);
312 static void virtio_rpmsg_destroy_ept(struct rpmsg_endpoint
*ept
)
314 struct virtio_rpmsg_channel
*vch
= to_virtio_rpmsg_channel(ept
->rpdev
);
316 __rpmsg_destroy_ept(vch
->vrp
, ept
);
319 static int virtio_rpmsg_announce_create(struct rpmsg_device
*rpdev
)
321 struct virtio_rpmsg_channel
*vch
= to_virtio_rpmsg_channel(rpdev
);
322 struct virtproc_info
*vrp
= vch
->vrp
;
323 struct device
*dev
= &rpdev
->dev
;
326 /* need to tell remote processor's name service about this channel ? */
327 if (rpdev
->announce
&& rpdev
->ept
&&
328 virtio_has_feature(vrp
->vdev
, VIRTIO_RPMSG_F_NS
)) {
329 struct rpmsg_ns_msg nsm
;
331 strncpy(nsm
.name
, rpdev
->id
.name
, RPMSG_NAME_SIZE
);
332 nsm
.addr
= cpu_to_rpmsg32(rpdev
, rpdev
->ept
->addr
);
333 nsm
.flags
= cpu_to_rpmsg32(rpdev
, RPMSG_NS_CREATE
);
335 err
= rpmsg_sendto(rpdev
->ept
, &nsm
, sizeof(nsm
), RPMSG_NS_ADDR
);
337 dev_err(dev
, "failed to announce service %d\n", err
);
343 static int virtio_rpmsg_announce_destroy(struct rpmsg_device
*rpdev
)
345 struct virtio_rpmsg_channel
*vch
= to_virtio_rpmsg_channel(rpdev
);
346 struct virtproc_info
*vrp
= vch
->vrp
;
347 struct device
*dev
= &rpdev
->dev
;
350 /* tell remote processor's name service we're removing this channel */
351 if (rpdev
->announce
&& rpdev
->ept
&&
352 virtio_has_feature(vrp
->vdev
, VIRTIO_RPMSG_F_NS
)) {
353 struct rpmsg_ns_msg nsm
;
355 strncpy(nsm
.name
, rpdev
->id
.name
, RPMSG_NAME_SIZE
);
356 nsm
.addr
= cpu_to_rpmsg32(rpdev
, rpdev
->ept
->addr
);
357 nsm
.flags
= cpu_to_rpmsg32(rpdev
, RPMSG_NS_DESTROY
);
359 err
= rpmsg_sendto(rpdev
->ept
, &nsm
, sizeof(nsm
), RPMSG_NS_ADDR
);
361 dev_err(dev
, "failed to announce service %d\n", err
);
367 static const struct rpmsg_device_ops virtio_rpmsg_ops
= {
368 .create_channel
= virtio_rpmsg_create_channel
,
369 .release_channel
= virtio_rpmsg_release_channel
,
370 .create_ept
= virtio_rpmsg_create_ept
,
371 .announce_create
= virtio_rpmsg_announce_create
,
372 .announce_destroy
= virtio_rpmsg_announce_destroy
,
375 static void virtio_rpmsg_release_device(struct device
*dev
)
377 struct rpmsg_device
*rpdev
= to_rpmsg_device(dev
);
378 struct virtio_rpmsg_channel
*vch
= to_virtio_rpmsg_channel(rpdev
);
384 * create an rpmsg channel using its name and address info.
385 * this function will be used to create both static and dynamic
388 static struct rpmsg_device
*__rpmsg_create_channel(struct virtproc_info
*vrp
,
389 struct rpmsg_channel_info
*chinfo
)
391 struct virtio_rpmsg_channel
*vch
;
392 struct rpmsg_device
*rpdev
;
393 struct device
*tmp
, *dev
= &vrp
->vdev
->dev
;
396 /* make sure a similar channel doesn't already exist */
397 tmp
= rpmsg_find_device(dev
, chinfo
);
399 /* decrement the matched device's refcount back */
401 dev_err(dev
, "channel %s:%x:%x already exist\n",
402 chinfo
->name
, chinfo
->src
, chinfo
->dst
);
406 vch
= kzalloc(sizeof(*vch
), GFP_KERNEL
);
410 /* Link the channel to our vrp */
413 /* Assign public information to the rpmsg_device */
415 rpdev
->src
= chinfo
->src
;
416 rpdev
->dst
= chinfo
->dst
;
417 rpdev
->ops
= &virtio_rpmsg_ops
;
418 rpdev
->little_endian
= virtio_is_little_endian(vrp
->vdev
);
421 * rpmsg server channels has predefined local address (for now),
422 * and their existence needs to be announced remotely
424 rpdev
->announce
= rpdev
->src
!= RPMSG_ADDR_ANY
;
426 strncpy(rpdev
->id
.name
, chinfo
->name
, RPMSG_NAME_SIZE
);
428 rpdev
->dev
.parent
= &vrp
->vdev
->dev
;
429 rpdev
->dev
.release
= virtio_rpmsg_release_device
;
430 ret
= rpmsg_register_device(rpdev
);
437 /* super simple buffer "allocator" that is just enough for now */
438 static void *get_a_tx_buf(struct virtproc_info
*vrp
)
443 /* support multiple concurrent senders */
444 mutex_lock(&vrp
->tx_lock
);
447 * either pick the next unused tx buffer
448 * (half of our buffers are used for sending messages)
450 if (vrp
->last_sbuf
< vrp
->num_bufs
/ 2)
451 ret
= vrp
->sbufs
+ vrp
->buf_size
* vrp
->last_sbuf
++;
452 /* or recycle a used one */
454 ret
= virtqueue_get_buf(vrp
->svq
, &len
);
456 mutex_unlock(&vrp
->tx_lock
);
462 * rpmsg_upref_sleepers() - enable "tx-complete" interrupts, if needed
463 * @vrp: virtual remote processor state
465 * This function is called before a sender is blocked, waiting for
466 * a tx buffer to become available.
468 * If we already have blocking senders, this function merely increases
469 * the "sleepers" reference count, and exits.
471 * Otherwise, if this is the first sender to block, we also enable
472 * virtio's tx callbacks, so we'd be immediately notified when a tx
473 * buffer is consumed (we rely on virtio's tx callback in order
474 * to wake up sleeping senders as soon as a tx buffer is used by the
477 static void rpmsg_upref_sleepers(struct virtproc_info
*vrp
)
479 /* support multiple concurrent senders */
480 mutex_lock(&vrp
->tx_lock
);
482 /* are we the first sleeping context waiting for tx buffers ? */
483 if (atomic_inc_return(&vrp
->sleepers
) == 1)
484 /* enable "tx-complete" interrupts before dozing off */
485 virtqueue_enable_cb(vrp
->svq
);
487 mutex_unlock(&vrp
->tx_lock
);
491 * rpmsg_downref_sleepers() - disable "tx-complete" interrupts, if needed
492 * @vrp: virtual remote processor state
494 * This function is called after a sender, that waited for a tx buffer
495 * to become available, is unblocked.
497 * If we still have blocking senders, this function merely decreases
498 * the "sleepers" reference count, and exits.
500 * Otherwise, if there are no more blocking senders, we also disable
501 * virtio's tx callbacks, to avoid the overhead incurred with handling
502 * those (now redundant) interrupts.
504 static void rpmsg_downref_sleepers(struct virtproc_info
*vrp
)
506 /* support multiple concurrent senders */
507 mutex_lock(&vrp
->tx_lock
);
509 /* are we the last sleeping context waiting for tx buffers ? */
510 if (atomic_dec_and_test(&vrp
->sleepers
))
511 /* disable "tx-complete" interrupts */
512 virtqueue_disable_cb(vrp
->svq
);
514 mutex_unlock(&vrp
->tx_lock
);
518 * rpmsg_send_offchannel_raw() - send a message across to the remote processor
519 * @rpdev: the rpmsg channel
520 * @src: source address
521 * @dst: destination address
522 * @data: payload of message
523 * @len: length of payload
524 * @wait: indicates whether caller should block in case no TX buffers available
526 * This function is the base implementation for all of the rpmsg sending API.
528 * It will send @data of length @len to @dst, and say it's from @src. The
529 * message will be sent to the remote processor which the @rpdev channel
532 * The message is sent using one of the TX buffers that are available for
533 * communication with this remote processor.
535 * If @wait is true, the caller will be blocked until either a TX buffer is
536 * available, or 15 seconds elapses (we don't want callers to
537 * sleep indefinitely due to misbehaving remote processors), and in that
538 * case -ERESTARTSYS is returned. The number '15' itself was picked
539 * arbitrarily; there's little point in asking drivers to provide a timeout
542 * Otherwise, if @wait is false, and there are no TX buffers available,
543 * the function will immediately fail, and -ENOMEM will be returned.
545 * Normally drivers shouldn't use this function directly; instead, drivers
546 * should use the appropriate rpmsg_{try}send{to, _offchannel} API
547 * (see include/linux/rpmsg.h).
549 * Returns 0 on success and an appropriate error value on failure.
551 static int rpmsg_send_offchannel_raw(struct rpmsg_device
*rpdev
,
553 void *data
, int len
, bool wait
)
555 struct virtio_rpmsg_channel
*vch
= to_virtio_rpmsg_channel(rpdev
);
556 struct virtproc_info
*vrp
= vch
->vrp
;
557 struct device
*dev
= &rpdev
->dev
;
558 struct scatterlist sg
;
559 struct rpmsg_hdr
*msg
;
562 /* bcasting isn't allowed */
563 if (src
== RPMSG_ADDR_ANY
|| dst
== RPMSG_ADDR_ANY
) {
564 dev_err(dev
, "invalid addr (src 0x%x, dst 0x%x)\n", src
, dst
);
569 * We currently use fixed-sized buffers, and therefore the payload
572 * One of the possible improvements here is either to support
573 * user-provided buffers (and then we can also support zero-copy
574 * messaging), or to improve the buffer allocator, to support
575 * variable-length buffer sizes.
577 if (len
> vrp
->buf_size
- sizeof(struct rpmsg_hdr
)) {
578 dev_err(dev
, "message is too big (%d)\n", len
);
583 msg
= get_a_tx_buf(vrp
);
587 /* no free buffer ? wait for one (but bail after 15 seconds) */
589 /* enable "tx-complete" interrupts, if not already enabled */
590 rpmsg_upref_sleepers(vrp
);
593 * sleep until a free buffer is available or 15 secs elapse.
594 * the timeout period is not configurable because there's
595 * little point in asking drivers to specify that.
596 * if later this happens to be required, it'd be easy to add.
598 err
= wait_event_interruptible_timeout(vrp
->sendq
,
599 (msg
= get_a_tx_buf(vrp
)),
600 msecs_to_jiffies(15000));
602 /* disable "tx-complete" interrupts if we're the last sleeper */
603 rpmsg_downref_sleepers(vrp
);
607 dev_err(dev
, "timeout waiting for a tx buffer\n");
612 msg
->len
= cpu_to_rpmsg16(rpdev
, len
);
614 msg
->src
= cpu_to_rpmsg32(rpdev
, src
);
615 msg
->dst
= cpu_to_rpmsg32(rpdev
, dst
);
617 memcpy(msg
->data
, data
, len
);
619 dev_dbg(dev
, "TX From 0x%x, To 0x%x, Len %d, Flags %d, Reserved %d\n",
620 src
, dst
, len
, msg
->flags
, msg
->reserved
);
621 #if defined(CONFIG_DYNAMIC_DEBUG)
622 dynamic_hex_dump("rpmsg_virtio TX: ", DUMP_PREFIX_NONE
, 16, 1,
623 msg
, sizeof(*msg
) + len
, true);
626 rpmsg_sg_init(&sg
, msg
, sizeof(*msg
) + len
);
628 mutex_lock(&vrp
->tx_lock
);
630 /* add message to the remote processor's virtqueue */
631 err
= virtqueue_add_outbuf(vrp
->svq
, &sg
, 1, msg
, GFP_KERNEL
);
634 * need to reclaim the buffer here, otherwise it's lost
635 * (memory won't leak, but rpmsg won't use it again for TX).
636 * this will wait for a buffer management overhaul.
638 dev_err(dev
, "virtqueue_add_outbuf failed: %d\n", err
);
642 /* tell the remote processor it has a pending message to read */
643 virtqueue_kick(vrp
->svq
);
645 mutex_unlock(&vrp
->tx_lock
);
649 static int virtio_rpmsg_send(struct rpmsg_endpoint
*ept
, void *data
, int len
)
651 struct rpmsg_device
*rpdev
= ept
->rpdev
;
652 u32 src
= ept
->addr
, dst
= rpdev
->dst
;
654 return rpmsg_send_offchannel_raw(rpdev
, src
, dst
, data
, len
, true);
657 static int virtio_rpmsg_sendto(struct rpmsg_endpoint
*ept
, void *data
, int len
,
660 struct rpmsg_device
*rpdev
= ept
->rpdev
;
663 return rpmsg_send_offchannel_raw(rpdev
, src
, dst
, data
, len
, true);
666 static int virtio_rpmsg_send_offchannel(struct rpmsg_endpoint
*ept
, u32 src
,
667 u32 dst
, void *data
, int len
)
669 struct rpmsg_device
*rpdev
= ept
->rpdev
;
671 return rpmsg_send_offchannel_raw(rpdev
, src
, dst
, data
, len
, true);
674 static int virtio_rpmsg_trysend(struct rpmsg_endpoint
*ept
, void *data
, int len
)
676 struct rpmsg_device
*rpdev
= ept
->rpdev
;
677 u32 src
= ept
->addr
, dst
= rpdev
->dst
;
679 return rpmsg_send_offchannel_raw(rpdev
, src
, dst
, data
, len
, false);
682 static int virtio_rpmsg_trysendto(struct rpmsg_endpoint
*ept
, void *data
,
685 struct rpmsg_device
*rpdev
= ept
->rpdev
;
688 return rpmsg_send_offchannel_raw(rpdev
, src
, dst
, data
, len
, false);
691 static int virtio_rpmsg_trysend_offchannel(struct rpmsg_endpoint
*ept
, u32 src
,
692 u32 dst
, void *data
, int len
)
694 struct rpmsg_device
*rpdev
= ept
->rpdev
;
696 return rpmsg_send_offchannel_raw(rpdev
, src
, dst
, data
, len
, false);
699 static int rpmsg_recv_single(struct virtproc_info
*vrp
, struct device
*dev
,
700 struct rpmsg_hdr
*msg
, unsigned int len
)
702 struct rpmsg_endpoint
*ept
;
703 struct scatterlist sg
;
704 bool little_endian
= virtio_is_little_endian(vrp
->vdev
);
705 unsigned int msg_len
= __rpmsg16_to_cpu(little_endian
, msg
->len
);
708 dev_dbg(dev
, "From: 0x%x, To: 0x%x, Len: %d, Flags: %d, Reserved: %d\n",
709 __rpmsg32_to_cpu(little_endian
, msg
->src
),
710 __rpmsg32_to_cpu(little_endian
, msg
->dst
), msg_len
,
711 __rpmsg16_to_cpu(little_endian
, msg
->flags
),
712 __rpmsg32_to_cpu(little_endian
, msg
->reserved
));
713 #if defined(CONFIG_DYNAMIC_DEBUG)
714 dynamic_hex_dump("rpmsg_virtio RX: ", DUMP_PREFIX_NONE
, 16, 1,
715 msg
, sizeof(*msg
) + msg_len
, true);
719 * We currently use fixed-sized buffers, so trivially sanitize
720 * the reported payload length.
722 if (len
> vrp
->buf_size
||
723 msg_len
> (len
- sizeof(struct rpmsg_hdr
))) {
724 dev_warn(dev
, "inbound msg too big: (%d, %d)\n", len
, msg_len
);
728 /* use the dst addr to fetch the callback of the appropriate user */
729 mutex_lock(&vrp
->endpoints_lock
);
731 ept
= idr_find(&vrp
->endpoints
, __rpmsg32_to_cpu(little_endian
, msg
->dst
));
733 /* let's make sure no one deallocates ept while we use it */
735 kref_get(&ept
->refcount
);
737 mutex_unlock(&vrp
->endpoints_lock
);
740 /* make sure ept->cb doesn't go away while we use it */
741 mutex_lock(&ept
->cb_lock
);
744 ept
->cb(ept
->rpdev
, msg
->data
, msg_len
, ept
->priv
,
745 __rpmsg32_to_cpu(little_endian
, msg
->src
));
747 mutex_unlock(&ept
->cb_lock
);
749 /* farewell, ept, we don't need you anymore */
750 kref_put(&ept
->refcount
, __ept_release
);
752 dev_warn(dev
, "msg received with no recipient\n");
754 /* publish the real size of the buffer */
755 rpmsg_sg_init(&sg
, msg
, vrp
->buf_size
);
757 /* add the buffer back to the remote processor's virtqueue */
758 err
= virtqueue_add_inbuf(vrp
->rvq
, &sg
, 1, msg
, GFP_KERNEL
);
760 dev_err(dev
, "failed to add a virtqueue buffer: %d\n", err
);
767 /* called when an rx buffer is used, and it's time to digest a message */
768 static void rpmsg_recv_done(struct virtqueue
*rvq
)
770 struct virtproc_info
*vrp
= rvq
->vdev
->priv
;
771 struct device
*dev
= &rvq
->vdev
->dev
;
772 struct rpmsg_hdr
*msg
;
773 unsigned int len
, msgs_received
= 0;
776 msg
= virtqueue_get_buf(rvq
, &len
);
778 dev_err(dev
, "uhm, incoming signal, but no used buffer ?\n");
783 err
= rpmsg_recv_single(vrp
, dev
, msg
, len
);
789 msg
= virtqueue_get_buf(rvq
, &len
);
792 dev_dbg(dev
, "Received %u messages\n", msgs_received
);
794 /* tell the remote processor we added another available rx buffer */
796 virtqueue_kick(vrp
->rvq
);
800 * This is invoked whenever the remote processor completed processing
801 * a TX msg we just sent it, and the buffer is put back to the used ring.
803 * Normally, though, we suppress this "tx complete" interrupt in order to
804 * avoid the incurred overhead.
806 static void rpmsg_xmit_done(struct virtqueue
*svq
)
808 struct virtproc_info
*vrp
= svq
->vdev
->priv
;
810 dev_dbg(&svq
->vdev
->dev
, "%s\n", __func__
);
812 /* wake up potential senders that are waiting for a tx buffer */
813 wake_up_interruptible(&vrp
->sendq
);
817 * Called to expose to user a /dev/rpmsg_ctrlX interface allowing to
818 * create endpoint-to-endpoint communication without associated RPMsg channel.
819 * The endpoints are rattached to the ctrldev RPMsg device.
821 static struct rpmsg_device
*rpmsg_virtio_add_ctrl_dev(struct virtio_device
*vdev
)
823 struct virtproc_info
*vrp
= vdev
->priv
;
824 struct virtio_rpmsg_channel
*vch
;
825 struct rpmsg_device
*rpdev_ctrl
;
828 vch
= kzalloc(sizeof(*vch
), GFP_KERNEL
);
830 return ERR_PTR(-ENOMEM
);
832 /* Link the channel to the vrp */
835 /* Assign public information to the rpmsg_device */
836 rpdev_ctrl
= &vch
->rpdev
;
837 rpdev_ctrl
->ops
= &virtio_rpmsg_ops
;
839 rpdev_ctrl
->dev
.parent
= &vrp
->vdev
->dev
;
840 rpdev_ctrl
->dev
.release
= virtio_rpmsg_release_device
;
841 rpdev_ctrl
->little_endian
= virtio_is_little_endian(vrp
->vdev
);
843 err
= rpmsg_chrdev_register_device(rpdev_ctrl
);
852 static void rpmsg_virtio_del_ctrl_dev(struct rpmsg_device
*rpdev_ctrl
)
856 kfree(to_virtio_rpmsg_channel(rpdev_ctrl
));
859 static int rpmsg_probe(struct virtio_device
*vdev
)
861 vq_callback_t
*vq_cbs
[] = { rpmsg_recv_done
, rpmsg_xmit_done
};
862 static const char * const names
[] = { "input", "output" };
863 struct virtqueue
*vqs
[2];
864 struct virtproc_info
*vrp
;
865 struct virtio_rpmsg_channel
*vch
= NULL
;
866 struct rpmsg_device
*rpdev_ns
, *rpdev_ctrl
;
869 size_t total_buf_space
;
872 vrp
= kzalloc(sizeof(*vrp
), GFP_KERNEL
);
878 idr_init(&vrp
->endpoints
);
879 mutex_init(&vrp
->endpoints_lock
);
880 mutex_init(&vrp
->tx_lock
);
881 init_waitqueue_head(&vrp
->sendq
);
883 /* We expect two virtqueues, rx and tx (and in this order) */
884 err
= virtio_find_vqs(vdev
, 2, vqs
, vq_cbs
, names
, NULL
);
891 /* we expect symmetric tx/rx vrings */
892 WARN_ON(virtqueue_get_vring_size(vrp
->rvq
) !=
893 virtqueue_get_vring_size(vrp
->svq
));
895 /* we need less buffers if vrings are small */
896 if (virtqueue_get_vring_size(vrp
->rvq
) < MAX_RPMSG_NUM_BUFS
/ 2)
897 vrp
->num_bufs
= virtqueue_get_vring_size(vrp
->rvq
) * 2;
899 vrp
->num_bufs
= MAX_RPMSG_NUM_BUFS
;
901 vrp
->buf_size
= MAX_RPMSG_BUF_SIZE
;
903 total_buf_space
= vrp
->num_bufs
* vrp
->buf_size
;
905 /* allocate coherent memory for the buffers */
906 bufs_va
= dma_alloc_coherent(vdev
->dev
.parent
,
907 total_buf_space
, &vrp
->bufs_dma
,
914 dev_dbg(&vdev
->dev
, "buffers: va %pK, dma %pad\n",
915 bufs_va
, &vrp
->bufs_dma
);
917 /* half of the buffers is dedicated for RX */
918 vrp
->rbufs
= bufs_va
;
920 /* and half is dedicated for TX */
921 vrp
->sbufs
= bufs_va
+ total_buf_space
/ 2;
923 /* set up the receive buffers */
924 for (i
= 0; i
< vrp
->num_bufs
/ 2; i
++) {
925 struct scatterlist sg
;
926 void *cpu_addr
= vrp
->rbufs
+ i
* vrp
->buf_size
;
928 rpmsg_sg_init(&sg
, cpu_addr
, vrp
->buf_size
);
930 err
= virtqueue_add_inbuf(vrp
->rvq
, &sg
, 1, cpu_addr
,
932 WARN_ON(err
); /* sanity check; this can't really happen */
935 /* suppress "tx-complete" interrupts */
936 virtqueue_disable_cb(vrp
->svq
);
940 rpdev_ctrl
= rpmsg_virtio_add_ctrl_dev(vdev
);
941 if (IS_ERR(rpdev_ctrl
)) {
942 err
= PTR_ERR(rpdev_ctrl
);
946 /* if supported by the remote processor, enable the name service */
947 if (virtio_has_feature(vdev
, VIRTIO_RPMSG_F_NS
)) {
948 vch
= kzalloc(sizeof(*vch
), GFP_KERNEL
);
954 /* Link the channel to our vrp */
957 /* Assign public information to the rpmsg_device */
958 rpdev_ns
= &vch
->rpdev
;
959 rpdev_ns
->ops
= &virtio_rpmsg_ops
;
960 rpdev_ns
->little_endian
= virtio_is_little_endian(vrp
->vdev
);
962 rpdev_ns
->dev
.parent
= &vrp
->vdev
->dev
;
963 rpdev_ns
->dev
.release
= virtio_rpmsg_release_device
;
965 err
= rpmsg_ns_register_device(rpdev_ns
);
971 * Prepare to kick but don't notify yet - we can't do this before
974 notify
= virtqueue_kick_prepare(vrp
->rvq
);
976 /* From this point on, we can notify and get callbacks. */
977 virtio_device_ready(vdev
);
979 /* tell the remote processor it can start sending messages */
981 * this might be concurrent with callbacks, but we are only
982 * doing notify, not a full kick here, so that's ok.
985 virtqueue_notify(vrp
->rvq
);
987 dev_info(&vdev
->dev
, "rpmsg host is online\n");
994 rpmsg_virtio_del_ctrl_dev(rpdev_ctrl
);
996 dma_free_coherent(vdev
->dev
.parent
, total_buf_space
,
997 bufs_va
, vrp
->bufs_dma
);
999 vdev
->config
->del_vqs(vrp
->vdev
);
1005 static int rpmsg_remove_device(struct device
*dev
, void *data
)
1007 device_unregister(dev
);
1012 static void rpmsg_remove(struct virtio_device
*vdev
)
1014 struct virtproc_info
*vrp
= vdev
->priv
;
1015 size_t total_buf_space
= vrp
->num_bufs
* vrp
->buf_size
;
1018 vdev
->config
->reset(vdev
);
1020 ret
= device_for_each_child(&vdev
->dev
, NULL
, rpmsg_remove_device
);
1022 dev_warn(&vdev
->dev
, "can't remove rpmsg device: %d\n", ret
);
1024 idr_destroy(&vrp
->endpoints
);
1026 vdev
->config
->del_vqs(vrp
->vdev
);
1028 dma_free_coherent(vdev
->dev
.parent
, total_buf_space
,
1029 vrp
->rbufs
, vrp
->bufs_dma
);
1034 static struct virtio_device_id id_table
[] = {
1035 { VIRTIO_ID_RPMSG
, VIRTIO_DEV_ANY_ID
},
1039 static unsigned int features
[] = {
1043 static struct virtio_driver virtio_ipc_driver
= {
1044 .feature_table
= features
,
1045 .feature_table_size
= ARRAY_SIZE(features
),
1046 .driver
.name
= KBUILD_MODNAME
,
1047 .driver
.owner
= THIS_MODULE
,
1048 .id_table
= id_table
,
1049 .probe
= rpmsg_probe
,
1050 .remove
= rpmsg_remove
,
1053 static int __init
rpmsg_init(void)
1057 ret
= register_virtio_driver(&virtio_ipc_driver
);
1059 pr_err("failed to register virtio driver: %d\n", ret
);
1063 subsys_initcall(rpmsg_init
);
1065 static void __exit
rpmsg_fini(void)
1067 unregister_virtio_driver(&virtio_ipc_driver
);
1069 module_exit(rpmsg_fini
);
1071 MODULE_DEVICE_TABLE(virtio
, id_table
);
1072 MODULE_DESCRIPTION("Virtio-based remote processor messaging bus");
1073 MODULE_LICENSE("GPL v2");