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>
38 * struct virtproc_info - virtual remote processor state
39 * @vdev: the virtio device
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
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
59 struct virtproc_info
{
60 struct virtio_device
*vdev
;
61 struct virtqueue
*rvq
, *svq
;
67 struct mutex endpoints_lock
;
68 wait_queue_head_t sendq
;
70 struct rpmsg_endpoint
*ns_ept
;
74 * struct rpmsg_channel_info - internal channel info representation
75 * @name: name of service
77 * @dst: destination address
79 struct rpmsg_channel_info
{
80 char name
[RPMSG_NAME_SIZE
];
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)
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.
92 * Each buffer will have 16 bytes for the msg header and 496 bytes for
95 * This will require a total space of 256KB for the buffers.
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.
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
105 #define RPMSG_NUM_BUFS (512)
106 #define RPMSG_BUF_SIZE (512)
107 #define RPMSG_TOTAL_BUF_SPACE (RPMSG_NUM_BUFS * RPMSG_BUF_SIZE)
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.
114 #define RPMSG_RESERVED_ADDRESSES (1024)
116 /* Address 53 is reserved for advertising remote services */
117 #define RPMSG_NS_ADDR (53)
119 /* sysfs show configuration fields */
120 #define rpmsg_show_attr(field, path, format_string) \
122 field##_show(struct device *dev, \
123 struct device_attribute *attr, char *buf) \
125 struct rpmsg_channel *rpdev = to_rpmsg_channel(dev); \
127 return sprintf(buf, format_string, rpdev->path); \
130 /* for more info, see Documentation/ABI/testing/sysfs-bus-rpmsg */
131 rpmsg_show_attr(name
, id
.name
, "%s\n");
132 rpmsg_show_attr(src
, src
, "0x%x\n");
133 rpmsg_show_attr(dst
, dst
, "0x%x\n");
134 rpmsg_show_attr(announce
, announce
? "true" : "false", "%s\n");
137 * Unique (and free running) index for rpmsg devices.
139 * Yeah, we're not recycling those numbers (yet?). will be easy
140 * to change if/when we want to.
142 static unsigned int rpmsg_dev_index
;
144 static ssize_t
modalias_show(struct device
*dev
,
145 struct device_attribute
*attr
, char *buf
)
147 struct rpmsg_channel
*rpdev
= to_rpmsg_channel(dev
);
149 return sprintf(buf
, RPMSG_DEVICE_MODALIAS_FMT
"\n", rpdev
->id
.name
);
152 static struct device_attribute rpmsg_dev_attrs
[] = {
161 /* rpmsg devices and drivers are matched using the service name */
162 static inline int rpmsg_id_match(const struct rpmsg_channel
*rpdev
,
163 const struct rpmsg_device_id
*id
)
165 return strncmp(id
->name
, rpdev
->id
.name
, RPMSG_NAME_SIZE
) == 0;
168 /* match rpmsg channel and rpmsg driver */
169 static int rpmsg_dev_match(struct device
*dev
, struct device_driver
*drv
)
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
;
176 for (i
= 0; ids
[i
].name
[0]; i
++)
177 if (rpmsg_id_match(rpdev
, &ids
[i
]))
183 static int rpmsg_uevent(struct device
*dev
, struct kobj_uevent_env
*env
)
185 struct rpmsg_channel
*rpdev
= to_rpmsg_channel(dev
);
187 return add_uevent_var(env
, "MODALIAS=" RPMSG_DEVICE_MODALIAS_FMT
,
191 /* for more info, see below documentation of rpmsg_create_ept() */
192 static struct rpmsg_endpoint
*__rpmsg_create_ept(struct virtproc_info
*vrp
,
193 struct rpmsg_channel
*rpdev
, rpmsg_rx_cb_t cb
,
194 void *priv
, u32 addr
)
196 int err
, tmpaddr
, request
;
197 struct rpmsg_endpoint
*ept
;
198 struct device
*dev
= rpdev
? &rpdev
->dev
: &vrp
->vdev
->dev
;
200 if (!idr_pre_get(&vrp
->endpoints
, GFP_KERNEL
))
203 ept
= kzalloc(sizeof(*ept
), GFP_KERNEL
);
205 dev_err(dev
, "failed to kzalloc a new ept\n");
213 /* do we need to allocate a local address ? */
214 request
= addr
== RPMSG_ADDR_ANY
? RPMSG_RESERVED_ADDRESSES
: addr
;
216 mutex_lock(&vrp
->endpoints_lock
);
218 /* bind the endpoint to an rpmsg address (and allocate one if needed) */
219 err
= idr_get_new_above(&vrp
->endpoints
, ept
, request
, &tmpaddr
);
221 dev_err(dev
, "idr_get_new_above failed: %d\n", err
);
225 /* make sure the user's address request is fulfilled, if relevant */
226 if (addr
!= RPMSG_ADDR_ANY
&& tmpaddr
!= addr
) {
227 dev_err(dev
, "address 0x%x already in use\n", addr
);
233 mutex_unlock(&vrp
->endpoints_lock
);
238 idr_remove(&vrp
->endpoints
, request
);
240 mutex_unlock(&vrp
->endpoints_lock
);
246 * rpmsg_create_ept() - create a new rpmsg_endpoint
247 * @rpdev: rpmsg channel device
248 * @cb: rx callback handler
249 * @priv: private data for the driver's use
250 * @addr: local rpmsg address to bind with @cb
252 * Every rpmsg address in the system is bound to an rx callback (so when
253 * inbound messages arrive, they are dispatched by the rpmsg bus using the
254 * appropriate callback handler) by means of an rpmsg_endpoint struct.
256 * This function allows drivers to create such an endpoint, and by that,
257 * bind a callback, and possibly some private data too, to an rpmsg address
258 * (either one that is known in advance, or one that will be dynamically
259 * assigned for them).
261 * Simple rpmsg drivers need not call rpmsg_create_ept, because an endpoint
262 * is already created for them when they are probed by the rpmsg bus
263 * (using the rx callback provided when they registered to the rpmsg bus).
265 * So things should just work for simple drivers: they already have an
266 * endpoint, their rx callback is bound to their rpmsg address, and when
267 * relevant inbound messages arrive (i.e. messages which their dst address
268 * equals to the src address of their rpmsg channel), the driver's handler
269 * is invoked to process it.
271 * That said, more complicated drivers might do need to allocate
272 * additional rpmsg addresses, and bind them to different rx callbacks.
273 * To accomplish that, those drivers need to call this function.
275 * Drivers should provide their @rpdev channel (so the new endpoint would belong
276 * to the same remote processor their channel belongs to), an rx callback
277 * function, an optional private data (which is provided back when the
278 * rx callback is invoked), and an address they want to bind with the
279 * callback. If @addr is RPMSG_ADDR_ANY, then rpmsg_create_ept will
280 * dynamically assign them an available rpmsg address (drivers should have
281 * a very good reason why not to always use RPMSG_ADDR_ANY here).
283 * Returns a pointer to the endpoint on success, or NULL on error.
285 struct rpmsg_endpoint
*rpmsg_create_ept(struct rpmsg_channel
*rpdev
,
286 rpmsg_rx_cb_t cb
, void *priv
, u32 addr
)
288 return __rpmsg_create_ept(rpdev
->vrp
, rpdev
, cb
, priv
, addr
);
290 EXPORT_SYMBOL(rpmsg_create_ept
);
293 * rpmsg_destroy_ept() - destroy an existing rpmsg endpoint
294 * @ept: endpoing to destroy
296 * Should be used by drivers to destroy an rpmsg endpoint previously
297 * created with rpmsg_create_ept().
299 void rpmsg_destroy_ept(struct rpmsg_endpoint
*ept
)
301 struct virtproc_info
*vrp
= ept
->rpdev
->vrp
;
303 mutex_lock(&vrp
->endpoints_lock
);
304 idr_remove(&vrp
->endpoints
, ept
->addr
);
305 mutex_unlock(&vrp
->endpoints_lock
);
309 EXPORT_SYMBOL(rpmsg_destroy_ept
);
312 * when an rpmsg driver is probed with a channel, we seamlessly create
313 * it an endpoint, binding its rx callback to a unique local rpmsg
316 * if we need to, we also announce about this channel to the remote
317 * processor (needed in case the driver is exposing an rpmsg service).
319 static int rpmsg_dev_probe(struct device
*dev
)
321 struct rpmsg_channel
*rpdev
= to_rpmsg_channel(dev
);
322 struct rpmsg_driver
*rpdrv
= to_rpmsg_driver(rpdev
->dev
.driver
);
323 struct virtproc_info
*vrp
= rpdev
->vrp
;
324 struct rpmsg_endpoint
*ept
;
327 ept
= rpmsg_create_ept(rpdev
, rpdrv
->callback
, NULL
, rpdev
->src
);
329 dev_err(dev
, "failed to create endpoint\n");
335 rpdev
->src
= ept
->addr
;
337 err
= rpdrv
->probe(rpdev
);
339 dev_err(dev
, "%s: failed: %d\n", __func__
, err
);
340 rpmsg_destroy_ept(ept
);
344 /* need to tell remote processor's name service about this channel ? */
345 if (rpdev
->announce
&&
346 virtio_has_feature(vrp
->vdev
, VIRTIO_RPMSG_F_NS
)) {
347 struct rpmsg_ns_msg nsm
;
349 strncpy(nsm
.name
, rpdev
->id
.name
, RPMSG_NAME_SIZE
);
350 nsm
.addr
= rpdev
->src
;
351 nsm
.flags
= RPMSG_NS_CREATE
;
353 err
= rpmsg_sendto(rpdev
, &nsm
, sizeof(nsm
), RPMSG_NS_ADDR
);
355 dev_err(dev
, "failed to announce service %d\n", err
);
362 static int rpmsg_dev_remove(struct device
*dev
)
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
;
369 /* tell remote processor's name service we're removing this channel */
370 if (rpdev
->announce
&&
371 virtio_has_feature(vrp
->vdev
, VIRTIO_RPMSG_F_NS
)) {
372 struct rpmsg_ns_msg nsm
;
374 strncpy(nsm
.name
, rpdev
->id
.name
, RPMSG_NAME_SIZE
);
375 nsm
.addr
= rpdev
->src
;
376 nsm
.flags
= RPMSG_NS_DESTROY
;
378 err
= rpmsg_sendto(rpdev
, &nsm
, sizeof(nsm
), RPMSG_NS_ADDR
);
380 dev_err(dev
, "failed to announce service %d\n", err
);
383 rpdrv
->remove(rpdev
);
385 rpmsg_destroy_ept(rpdev
->ept
);
390 static struct bus_type rpmsg_bus
= {
392 .match
= rpmsg_dev_match
,
393 .dev_attrs
= rpmsg_dev_attrs
,
394 .uevent
= rpmsg_uevent
,
395 .probe
= rpmsg_dev_probe
,
396 .remove
= rpmsg_dev_remove
,
400 * register_rpmsg_driver() - register an rpmsg driver with the rpmsg bus
401 * @rpdrv: pointer to a struct rpmsg_driver
403 * Returns 0 on success, and an appropriate error value on failure.
405 int register_rpmsg_driver(struct rpmsg_driver
*rpdrv
)
407 rpdrv
->drv
.bus
= &rpmsg_bus
;
408 return driver_register(&rpdrv
->drv
);
410 EXPORT_SYMBOL(register_rpmsg_driver
);
413 * unregister_rpmsg_driver() - unregister an rpmsg driver from the rpmsg bus
414 * @rpdrv: pointer to a struct rpmsg_driver
416 * Returns 0 on success, and an appropriate error value on failure.
418 void unregister_rpmsg_driver(struct rpmsg_driver
*rpdrv
)
420 driver_unregister(&rpdrv
->drv
);
422 EXPORT_SYMBOL(unregister_rpmsg_driver
);
424 static void rpmsg_release_device(struct device
*dev
)
426 struct rpmsg_channel
*rpdev
= to_rpmsg_channel(dev
);
432 * match an rpmsg channel with a channel info struct.
433 * this is used to make sure we're not creating rpmsg devices for channels
434 * that already exist.
436 static int rpmsg_channel_match(struct device
*dev
, void *data
)
438 struct rpmsg_channel_info
*chinfo
= data
;
439 struct rpmsg_channel
*rpdev
= to_rpmsg_channel(dev
);
441 if (chinfo
->src
!= RPMSG_ADDR_ANY
&& chinfo
->src
!= rpdev
->src
)
444 if (chinfo
->dst
!= RPMSG_ADDR_ANY
&& chinfo
->dst
!= rpdev
->dst
)
447 if (strncmp(chinfo
->name
, rpdev
->id
.name
, RPMSG_NAME_SIZE
))
450 /* found a match ! */
455 * create an rpmsg channel using its name and address info.
456 * this function will be used to create both static and dynamic
459 static struct rpmsg_channel
*rpmsg_create_channel(struct virtproc_info
*vrp
,
460 struct rpmsg_channel_info
*chinfo
)
462 struct rpmsg_channel
*rpdev
;
463 struct device
*tmp
, *dev
= &vrp
->vdev
->dev
;
466 /* make sure a similar channel doesn't already exist */
467 tmp
= device_find_child(dev
, chinfo
, rpmsg_channel_match
);
469 /* decrement the matched device's refcount back */
471 dev_err(dev
, "channel %s:%x:%x already exist\n",
472 chinfo
->name
, chinfo
->src
, chinfo
->dst
);
476 rpdev
= kzalloc(sizeof(struct rpmsg_channel
), GFP_KERNEL
);
478 pr_err("kzalloc failed\n");
483 rpdev
->src
= chinfo
->src
;
484 rpdev
->dst
= chinfo
->dst
;
487 * rpmsg server channels has predefined local address (for now),
488 * and their existence needs to be announced remotely
490 rpdev
->announce
= rpdev
->src
!= RPMSG_ADDR_ANY
? true : false;
492 strncpy(rpdev
->id
.name
, chinfo
->name
, RPMSG_NAME_SIZE
);
494 /* very simple device indexing plumbing which is enough for now */
495 dev_set_name(&rpdev
->dev
, "rpmsg%d", rpmsg_dev_index
++);
497 rpdev
->dev
.parent
= &vrp
->vdev
->dev
;
498 rpdev
->dev
.bus
= &rpmsg_bus
;
499 rpdev
->dev
.release
= rpmsg_release_device
;
501 ret
= device_register(&rpdev
->dev
);
503 dev_err(dev
, "device_register failed: %d\n", ret
);
504 put_device(&rpdev
->dev
);
512 * find an existing channel using its name + address properties,
515 static int rpmsg_destroy_channel(struct virtproc_info
*vrp
,
516 struct rpmsg_channel_info
*chinfo
)
518 struct virtio_device
*vdev
= vrp
->vdev
;
521 dev
= device_find_child(&vdev
->dev
, chinfo
, rpmsg_channel_match
);
525 device_unregister(dev
);
532 /* super simple buffer "allocator" that is just enough for now */
533 static void *get_a_tx_buf(struct virtproc_info
*vrp
)
538 /* support multiple concurrent senders */
539 mutex_lock(&vrp
->tx_lock
);
542 * either pick the next unused tx buffer
543 * (half of our buffers are used for sending messages)
545 if (vrp
->last_sbuf
< RPMSG_NUM_BUFS
/ 2)
546 ret
= vrp
->sbufs
+ RPMSG_BUF_SIZE
* vrp
->last_sbuf
++;
547 /* or recycle a used one */
549 ret
= virtqueue_get_buf(vrp
->svq
, &len
);
551 mutex_unlock(&vrp
->tx_lock
);
557 * rpmsg_upref_sleepers() - enable "tx-complete" interrupts, if needed
558 * @vrp: virtual remote processor state
560 * This function is called before a sender is blocked, waiting for
561 * a tx buffer to become available.
563 * If we already have blocking senders, this function merely increases
564 * the "sleepers" reference count, and exits.
566 * Otherwise, if this is the first sender to block, we also enable
567 * virtio's tx callbacks, so we'd be immediately notified when a tx
568 * buffer is consumed (we rely on virtio's tx callback in order
569 * to wake up sleeping senders as soon as a tx buffer is used by the
572 static void rpmsg_upref_sleepers(struct virtproc_info
*vrp
)
574 /* support multiple concurrent senders */
575 mutex_lock(&vrp
->tx_lock
);
577 /* are we the first sleeping context waiting for tx buffers ? */
578 if (atomic_inc_return(&vrp
->sleepers
) == 1)
579 /* enable "tx-complete" interrupts before dozing off */
580 virtqueue_enable_cb(vrp
->svq
);
582 mutex_unlock(&vrp
->tx_lock
);
586 * rpmsg_downref_sleepers() - disable "tx-complete" interrupts, if needed
587 * @vrp: virtual remote processor state
589 * This function is called after a sender, that waited for a tx buffer
590 * to become available, is unblocked.
592 * If we still have blocking senders, this function merely decreases
593 * the "sleepers" reference count, and exits.
595 * Otherwise, if there are no more blocking senders, we also disable
596 * virtio's tx callbacks, to avoid the overhead incurred with handling
597 * those (now redundant) interrupts.
599 static void rpmsg_downref_sleepers(struct virtproc_info
*vrp
)
601 /* support multiple concurrent senders */
602 mutex_lock(&vrp
->tx_lock
);
604 /* are we the last sleeping context waiting for tx buffers ? */
605 if (atomic_dec_and_test(&vrp
->sleepers
))
606 /* disable "tx-complete" interrupts */
607 virtqueue_disable_cb(vrp
->svq
);
609 mutex_unlock(&vrp
->tx_lock
);
613 * rpmsg_send_offchannel_raw() - send a message across to the remote processor
614 * @rpdev: the rpmsg channel
615 * @src: source address
616 * @dst: destination address
617 * @data: payload of message
618 * @len: length of payload
619 * @wait: indicates whether caller should block in case no TX buffers available
621 * This function is the base implementation for all of the rpmsg sending API.
623 * It will send @data of length @len to @dst, and say it's from @src. The
624 * message will be sent to the remote processor which the @rpdev channel
627 * The message is sent using one of the TX buffers that are available for
628 * communication with this remote processor.
630 * If @wait is true, the caller will be blocked until either a TX buffer is
631 * available, or 15 seconds elapses (we don't want callers to
632 * sleep indefinitely due to misbehaving remote processors), and in that
633 * case -ERESTARTSYS is returned. The number '15' itself was picked
634 * arbitrarily; there's little point in asking drivers to provide a timeout
637 * Otherwise, if @wait is false, and there are no TX buffers available,
638 * the function will immediately fail, and -ENOMEM will be returned.
640 * Normally drivers shouldn't use this function directly; instead, drivers
641 * should use the appropriate rpmsg_{try}send{to, _offchannel} API
642 * (see include/linux/rpmsg.h).
644 * Returns 0 on success and an appropriate error value on failure.
646 int rpmsg_send_offchannel_raw(struct rpmsg_channel
*rpdev
, u32 src
, u32 dst
,
647 void *data
, int len
, bool wait
)
649 struct virtproc_info
*vrp
= rpdev
->vrp
;
650 struct device
*dev
= &rpdev
->dev
;
651 struct scatterlist sg
;
652 struct rpmsg_hdr
*msg
;
655 /* bcasting isn't allowed */
656 if (src
== RPMSG_ADDR_ANY
|| dst
== RPMSG_ADDR_ANY
) {
657 dev_err(dev
, "invalid addr (src 0x%x, dst 0x%x)\n", src
, dst
);
662 * We currently use fixed-sized buffers, and therefore the payload
665 * One of the possible improvements here is either to support
666 * user-provided buffers (and then we can also support zero-copy
667 * messaging), or to improve the buffer allocator, to support
668 * variable-length buffer sizes.
670 if (len
> RPMSG_BUF_SIZE
- sizeof(struct rpmsg_hdr
)) {
671 dev_err(dev
, "message is too big (%d)\n", len
);
676 msg
= get_a_tx_buf(vrp
);
680 /* no free buffer ? wait for one (but bail after 15 seconds) */
682 /* enable "tx-complete" interrupts, if not already enabled */
683 rpmsg_upref_sleepers(vrp
);
686 * sleep until a free buffer is available or 15 secs elapse.
687 * the timeout period is not configurable because there's
688 * little point in asking drivers to specify that.
689 * if later this happens to be required, it'd be easy to add.
691 err
= wait_event_interruptible_timeout(vrp
->sendq
,
692 (msg
= get_a_tx_buf(vrp
)),
693 msecs_to_jiffies(15000));
695 /* disable "tx-complete" interrupts if we're the last sleeper */
696 rpmsg_downref_sleepers(vrp
);
700 dev_err(dev
, "timeout waiting for a tx buffer\n");
710 memcpy(msg
->data
, data
, len
);
712 dev_dbg(dev
, "TX From 0x%x, To 0x%x, Len %d, Flags %d, Reserved %d\n",
713 msg
->src
, msg
->dst
, msg
->len
,
714 msg
->flags
, msg
->reserved
);
715 print_hex_dump(KERN_DEBUG
, "rpmsg_virtio TX: ", DUMP_PREFIX_NONE
, 16, 1,
716 msg
, sizeof(*msg
) + msg
->len
, true);
718 sg_init_one(&sg
, msg
, sizeof(*msg
) + len
);
720 mutex_lock(&vrp
->tx_lock
);
722 /* add message to the remote processor's virtqueue */
723 err
= virtqueue_add_buf_gfp(vrp
->svq
, &sg
, 1, 0, msg
, GFP_KERNEL
);
726 * need to reclaim the buffer here, otherwise it's lost
727 * (memory won't leak, but rpmsg won't use it again for TX).
728 * this will wait for a buffer management overhaul.
730 dev_err(dev
, "virtqueue_add_buf_gfp failed: %d\n", err
);
734 /* tell the remote processor it has a pending message to read */
735 virtqueue_kick(vrp
->svq
);
739 mutex_unlock(&vrp
->tx_lock
);
742 EXPORT_SYMBOL(rpmsg_send_offchannel_raw
);
744 /* called when an rx buffer is used, and it's time to digest a message */
745 static void rpmsg_recv_done(struct virtqueue
*rvq
)
747 struct rpmsg_hdr
*msg
;
749 struct rpmsg_endpoint
*ept
;
750 struct scatterlist sg
;
751 struct virtproc_info
*vrp
= rvq
->vdev
->priv
;
752 struct device
*dev
= &rvq
->vdev
->dev
;
755 msg
= virtqueue_get_buf(rvq
, &len
);
757 dev_err(dev
, "uhm, incoming signal, but no used buffer ?\n");
761 dev_dbg(dev
, "From: 0x%x, To: 0x%x, Len: %d, Flags: %d, Reserved: %d\n",
762 msg
->src
, msg
->dst
, msg
->len
,
763 msg
->flags
, msg
->reserved
);
764 print_hex_dump(KERN_DEBUG
, "rpmsg_virtio RX: ", DUMP_PREFIX_NONE
, 16, 1,
765 msg
, sizeof(*msg
) + msg
->len
, true);
767 /* use the dst addr to fetch the callback of the appropriate user */
768 mutex_lock(&vrp
->endpoints_lock
);
769 ept
= idr_find(&vrp
->endpoints
, msg
->dst
);
770 mutex_unlock(&vrp
->endpoints_lock
);
773 ept
->cb(ept
->rpdev
, msg
->data
, msg
->len
, ept
->priv
, msg
->src
);
775 dev_warn(dev
, "msg received with no recepient\n");
777 sg_init_one(&sg
, msg
, sizeof(*msg
) + len
);
779 /* add the buffer back to the remote processor's virtqueue */
780 err
= virtqueue_add_buf_gfp(vrp
->rvq
, &sg
, 0, 1, msg
, GFP_KERNEL
);
782 dev_err(dev
, "failed to add a virtqueue buffer: %d\n", err
);
786 /* tell the remote processor we added another available rx buffer */
787 virtqueue_kick(vrp
->rvq
);
791 * This is invoked whenever the remote processor completed processing
792 * a TX msg we just sent it, and the buffer is put back to the used ring.
794 * Normally, though, we suppress this "tx complete" interrupt in order to
795 * avoid the incurred overhead.
797 static void rpmsg_xmit_done(struct virtqueue
*svq
)
799 struct virtproc_info
*vrp
= svq
->vdev
->priv
;
801 dev_dbg(&svq
->vdev
->dev
, "%s\n", __func__
);
803 /* wake up potential senders that are waiting for a tx buffer */
804 wake_up_interruptible(&vrp
->sendq
);
807 /* invoked when a name service announcement arrives */
808 static void rpmsg_ns_cb(struct rpmsg_channel
*rpdev
, void *data
, int len
,
811 struct rpmsg_ns_msg
*msg
= data
;
812 struct rpmsg_channel
*newch
;
813 struct rpmsg_channel_info chinfo
;
814 struct virtproc_info
*vrp
= priv
;
815 struct device
*dev
= &vrp
->vdev
->dev
;
818 print_hex_dump(KERN_DEBUG
, "NS announcement: ",
819 DUMP_PREFIX_NONE
, 16, 1,
822 if (len
!= sizeof(*msg
)) {
823 dev_err(dev
, "malformed ns msg (%d)\n", len
);
828 * the name service ept does _not_ belong to a real rpmsg channel,
829 * and is handled by the rpmsg bus itself.
830 * for sanity reasons, make sure a valid rpdev has _not_ sneaked
834 dev_err(dev
, "anomaly: ns ept has an rpdev handle\n");
838 /* don't trust the remote processor for null terminating the name */
839 msg
->name
[RPMSG_NAME_SIZE
- 1] = '\0';
841 dev_info(dev
, "%sing channel %s addr 0x%x\n",
842 msg
->flags
& RPMSG_NS_DESTROY
? "destroy" : "creat",
843 msg
->name
, msg
->addr
);
845 strncpy(chinfo
.name
, msg
->name
, sizeof(chinfo
.name
));
846 chinfo
.src
= RPMSG_ADDR_ANY
;
847 chinfo
.dst
= msg
->addr
;
849 if (msg
->flags
& RPMSG_NS_DESTROY
) {
850 ret
= rpmsg_destroy_channel(vrp
, &chinfo
);
852 dev_err(dev
, "rpmsg_destroy_channel failed: %d\n", ret
);
854 newch
= rpmsg_create_channel(vrp
, &chinfo
);
856 dev_err(dev
, "rpmsg_create_channel failed\n");
860 static int rpmsg_probe(struct virtio_device
*vdev
)
862 vq_callback_t
*vq_cbs
[] = { rpmsg_recv_done
, rpmsg_xmit_done
};
863 const char *names
[] = { "input", "output" };
864 struct virtqueue
*vqs
[2];
865 struct virtproc_info
*vrp
;
869 vrp
= kzalloc(sizeof(*vrp
), GFP_KERNEL
);
875 idr_init(&vrp
->endpoints
);
876 mutex_init(&vrp
->endpoints_lock
);
877 mutex_init(&vrp
->tx_lock
);
878 init_waitqueue_head(&vrp
->sendq
);
880 /* We expect two virtqueues, rx and tx (and in this order) */
881 err
= vdev
->config
->find_vqs(vdev
, 2, vqs
, vq_cbs
, names
);
888 /* allocate coherent memory for the buffers */
889 bufs_va
= dma_alloc_coherent(vdev
->dev
.parent
, RPMSG_TOTAL_BUF_SPACE
,
890 &vrp
->bufs_dma
, GFP_KERNEL
);
894 dev_dbg(&vdev
->dev
, "buffers: va %p, dma 0x%x\n", bufs_va
,
897 /* half of the buffers is dedicated for RX */
898 vrp
->rbufs
= bufs_va
;
900 /* and half is dedicated for TX */
901 vrp
->sbufs
= bufs_va
+ RPMSG_TOTAL_BUF_SPACE
/ 2;
903 /* set up the receive buffers */
904 for (i
= 0; i
< RPMSG_NUM_BUFS
/ 2; i
++) {
905 struct scatterlist sg
;
906 void *cpu_addr
= vrp
->rbufs
+ i
* RPMSG_BUF_SIZE
;
908 sg_init_one(&sg
, cpu_addr
, RPMSG_BUF_SIZE
);
910 err
= virtqueue_add_buf_gfp(vrp
->rvq
, &sg
, 0, 1, cpu_addr
,
912 WARN_ON(err
< 0); /* sanity check; this can't really happen */
915 /* suppress "tx-complete" interrupts */
916 virtqueue_disable_cb(vrp
->svq
);
920 /* if supported by the remote processor, enable the name service */
921 if (virtio_has_feature(vdev
, VIRTIO_RPMSG_F_NS
)) {
922 /* a dedicated endpoint handles the name service msgs */
923 vrp
->ns_ept
= __rpmsg_create_ept(vrp
, NULL
, rpmsg_ns_cb
,
926 dev_err(&vdev
->dev
, "failed to create the ns ept\n");
932 /* tell the remote processor it can start sending messages */
933 virtqueue_kick(vrp
->rvq
);
935 dev_info(&vdev
->dev
, "rpmsg host is online\n");
940 dma_free_coherent(vdev
->dev
.parent
, RPMSG_TOTAL_BUF_SPACE
, bufs_va
,
943 vdev
->config
->del_vqs(vrp
->vdev
);
949 static int rpmsg_remove_device(struct device
*dev
, void *data
)
951 device_unregister(dev
);
956 static void __devexit
rpmsg_remove(struct virtio_device
*vdev
)
958 struct virtproc_info
*vrp
= vdev
->priv
;
961 vdev
->config
->reset(vdev
);
963 ret
= device_for_each_child(&vdev
->dev
, NULL
, rpmsg_remove_device
);
965 dev_warn(&vdev
->dev
, "can't remove rpmsg device: %d\n", ret
);
967 idr_remove_all(&vrp
->endpoints
);
968 idr_destroy(&vrp
->endpoints
);
970 vdev
->config
->del_vqs(vrp
->vdev
);
972 dma_free_coherent(vdev
->dev
.parent
, RPMSG_TOTAL_BUF_SPACE
,
973 vrp
->rbufs
, vrp
->bufs_dma
);
978 static struct virtio_device_id id_table
[] = {
979 { VIRTIO_ID_RPMSG
, VIRTIO_DEV_ANY_ID
},
983 static unsigned int features
[] = {
987 static struct virtio_driver virtio_ipc_driver
= {
988 .feature_table
= features
,
989 .feature_table_size
= ARRAY_SIZE(features
),
990 .driver
.name
= KBUILD_MODNAME
,
991 .driver
.owner
= THIS_MODULE
,
992 .id_table
= id_table
,
993 .probe
= rpmsg_probe
,
994 .remove
= __devexit_p(rpmsg_remove
),
997 static int __init
rpmsg_init(void)
1001 ret
= bus_register(&rpmsg_bus
);
1003 pr_err("failed to register rpmsg bus: %d\n", ret
);
1007 ret
= register_virtio_driver(&virtio_ipc_driver
);
1009 pr_err("failed to register virtio driver: %d\n", ret
);
1010 bus_unregister(&rpmsg_bus
);
1015 module_init(rpmsg_init
);
1017 static void __exit
rpmsg_fini(void)
1019 unregister_virtio_driver(&virtio_ipc_driver
);
1020 bus_unregister(&rpmsg_bus
);
1022 module_exit(rpmsg_fini
);
1024 MODULE_DEVICE_TABLE(virtio
, id_table
);
1025 MODULE_DESCRIPTION("Virtio-based remote processor messaging bus");
1026 MODULE_LICENSE("GPL v2");