/**
* rpmsg_send_offchannel_raw() - send a message across to the remote processor
* @rpdev: the rpmsg channel
* @src: source address
* @dst: destination address
* @data: payload of message
* @len: length of payload
* @wait: indicates whether caller should block in case no TX buffers available
*
* This function is the base implementation for all of the rpmsg sending API.
*
* It will send @data of length @len to @dst, and say it's from @src. The
* message will be sent to the remote processor which the @rpdev channel
* belongs to.
*
* The message is sent using one of the TX buffers that are available for
* communication with this remote processor.
*
* If @wait is true, the caller will be blocked until either a TX buffer is
* available, or 15 seconds elapses (we don't want callers to
* sleep indefinitely due to misbehaving remote processors), and in that
* case -ERESTARTSYS is returned. The number '15' itself was picked
* arbitrarily; there's little point in asking drivers to provide a timeout
* value themselves.
*
* Otherwise, if @wait is false, and there are no TX buffers available,
* the function will immediately fail, and -ENOMEM will be returned.
*
* Normally drivers shouldn't use this function directly; instead, drivers
* should use the appropriate rpmsg_{try}send{to, _offchannel} API
* (see include/linux/rpmsg.h).
*
* Returns 0 on success and an appropriate error value on failure.
*/
int rpmsg_send_offchannel_raw(struct rpmsg_channel *rpdev, u32 src, u32 dst,
void *data, int len, bool wait)
{
struct virtproc_info *vrp = rpdev->vrp;
struct device *dev = &rpdev->dev;
struct scatterlist sg;
struct rpmsg_hdr *msg;
int err;
/* bcasting isn't allowed */
if (src == RPMSG_ADDR_ANY || dst == RPMSG_ADDR_ANY) {
dev_err(dev, "invalid addr (src 0x%x, dst 0x%x)\n", src, dst);
return -EINVAL;
}
/*
* We currently use fixed-sized buffers, and therefore the payload
* length is limited.
*
* One of the possible improvements here is either to support
* user-provided buffers (and then we can also support zero-copy
* messaging), or to improve the buffer allocator, to support
* variable-length buffer sizes.
*/
if (len > RPMSG_BUF_SIZE - sizeof(struct rpmsg_hdr)) {
dev_err(dev, "message is too big (%d)\n", len);
return -EMSGSIZE;
}
/* grab a buffer */
msg = get_a_tx_buf(vrp);
if (!msg && !wait)
return -ENOMEM;
/* no free buffer ? wait for one (but bail after 15 seconds) */
while (!msg) {
/* enable "tx-complete" interrupts, if not already enabled */
rpmsg_upref_sleepers(vrp);
/*
* sleep until a free buffer is available or 15 secs elapse.
* the timeout period is not configurable because there's
* little point in asking drivers to specify that.
* if later this happens to be required, it'd be easy to add.
*/
err = wait_event_interruptible_timeout(vrp->sendq,
(msg = get_a_tx_buf(vrp)),
msecs_to_jiffies(15000));
/* disable "tx-complete" interrupts if we're the last sleeper */
rpmsg_downref_sleepers(vrp);
/* timeout ? */
if (!err) {
dev_err(dev, "timeout waiting for a tx buffer\n");
return -ERESTARTSYS;
}
}
msg->len = len;
msg->flags = 0;
msg->src = src;
msg->dst = dst;
msg->reserved = 0;
memcpy(msg->data, data, len);
dev_dbg(dev, "TX From 0x%x, To 0x%x, Len %d, Flags %d, Reserved %d\n",
msg->src, msg->dst, msg->len,
msg->flags, msg->reserved);
print_hex_dump(KERN_DEBUG, "rpmsg_virtio TX: ", DUMP_PREFIX_NONE, 16, 1,
msg, sizeof(*msg) + msg->len, true);
sg_init_one(&sg, msg, sizeof(*msg) + len);
mutex_lock(&vrp->tx_lock);
/* add message to the remote processor's virtqueue */
err = virtqueue_add_buf(vrp->svq, &sg, 1, 0, msg, GFP_KERNEL);
if (err) {
/*
* need to reclaim the buffer here, otherwise it's lost
* (memory won't leak, but rpmsg won't use it again for TX).
* this will wait for a buffer management overhaul.
*/
dev_err(dev, "virtqueue_add_buf failed: %d\n", err);
goto out;
}
/* tell the remote processor it has a pending message to read */
virtqueue_kick(vrp->svq);
out:
mutex_unlock(&vrp->tx_lock);
return err;
}
int rpmsg_send_offchannel_raw(struct rpmsg_channel *rpdev, u32 src, u32 dst,
void *data, int len, bool wait)
{
struct virtproc_info *vrp = rpdev->vrp;
struct device *dev = &rpdev->dev;
struct scatterlist sg;
struct rpmsg_hdr *msg;
int err;
if (src == RPMSG_ADDR_ANY || dst == RPMSG_ADDR_ANY) {
dev_err(dev, "invalid addr (src 0x%x, dst 0x%x)\n", src, dst);
return -EINVAL;
}
if (len > RPMSG_BUF_SIZE - sizeof(struct rpmsg_hdr)) {
dev_err(dev, "message is too big (%d)\n", len);
return -EMSGSIZE;
}
msg = get_a_tx_buf(vrp);
if (!msg && !wait)
return -ENOMEM;
while (!msg) {
rpmsg_upref_sleepers(vrp);
err = wait_event_interruptible_timeout(vrp->sendq,
(msg = get_a_tx_buf(vrp)),
msecs_to_jiffies(15000));
rpmsg_downref_sleepers(vrp);
if (!err) {
dev_err(dev, "timeout waiting for a tx buffer\n");
return -ERESTARTSYS;
}
}
msg->len = len;
msg->flags = 0;
msg->src = src;
msg->dst = dst;
msg->reserved = 0;
memcpy(msg->data, data, len);
dev_dbg(dev, "TX From 0x%x, To 0x%x, Len %d, Flags %d, Reserved %d\n",
msg->src, msg->dst, msg->len,
msg->flags, msg->reserved);
print_hex_dump(KERN_DEBUG, "rpmsg_virtio TX: ", DUMP_PREFIX_NONE, 16, 1,
msg, sizeof(*msg) + msg->len, true);
sg_init_one(&sg, msg, sizeof(*msg) + len);
mutex_lock(&vrp->tx_lock);
err = virtqueue_add_buf(vrp->svq, &sg, 1, 0, msg, GFP_KERNEL);
if (err < 0) {
dev_err(dev, "virtqueue_add_buf failed: %d\n", err);
goto out;
}
virtqueue_kick(vrp->svq);
err = 0;
out:
mutex_unlock(&vrp->tx_lock);
return err;
}