[PATCH v4 1/5] rpmsg: virtio_rpmsg: set rpmsg_buf_size customizable

From: Loic Pallardy
Date: Tue Mar 28 2017 - 07:52:07 EST


Rpmsg buffer size is currently fixed to 512 bytes.
This patch introduces a new capability in struct virtproc_info
to tune shared buffer size between host and coprocessor
according to the needs.

Signed-off-by: Loic Pallardy <loic.pallardy@xxxxxx>
---
Changes since V1:
- Initialize vrp->num_bufs before use.
- Alignment with open parenthesis.

No change since v2.
---
drivers/rpmsg/virtio_rpmsg_bus.c | 22 +++++++++++++---------
1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/drivers/rpmsg/virtio_rpmsg_bus.c b/drivers/rpmsg/virtio_rpmsg_bus.c
index 5e66e08..3f44a03 100644
--- a/drivers/rpmsg/virtio_rpmsg_bus.c
+++ b/drivers/rpmsg/virtio_rpmsg_bus.c
@@ -45,6 +45,7 @@
* @rbufs: kernel address of rx buffers
* @sbufs: kernel address of tx buffers
* @num_bufs: total number of buffers for rx and tx
+ * @buf_size: size of one rx or tx buffer
* @last_sbuf: index of last tx buffer used
* @bufs_dma: dma base addr of the buffers
* @tx_lock: protects svq, sbufs and sleepers, to allow concurrent senders.
@@ -65,6 +66,7 @@ struct virtproc_info {
struct virtqueue *rvq, *svq;
void *rbufs, *sbufs;
unsigned int num_bufs;
+ unsigned int buf_size;
int last_sbuf;
dma_addr_t bufs_dma;
struct mutex tx_lock;
@@ -158,7 +160,7 @@ struct virtio_rpmsg_channel {
* processor.
*/
#define MAX_RPMSG_NUM_BUFS (512)
-#define RPMSG_BUF_SIZE (512)
+#define MAX_RPMSG_BUF_SIZE (512)

/*
* Local addresses are dynamically allocated on-demand.
@@ -429,7 +431,7 @@ static void *get_a_tx_buf(struct virtproc_info *vrp)
* (half of our buffers are used for sending messages)
*/
if (vrp->last_sbuf < vrp->num_bufs / 2)
- ret = vrp->sbufs + RPMSG_BUF_SIZE * vrp->last_sbuf++;
+ ret = vrp->sbufs + vrp->buf_size * vrp->last_sbuf++;
/* or recycle a used one */
else
ret = virtqueue_get_buf(vrp->svq, &len);
@@ -555,7 +557,7 @@ static int rpmsg_send_offchannel_raw(struct rpmsg_device *rpdev,
* messaging), or to improve the buffer allocator, to support
* variable-length buffer sizes.
*/
- if (len > RPMSG_BUF_SIZE - sizeof(struct rpmsg_hdr)) {
+ if (len > vrp->buf_size - sizeof(struct rpmsg_hdr)) {
dev_err(dev, "message is too big (%d)\n", len);
return -EMSGSIZE;
}
@@ -696,7 +698,7 @@ static int rpmsg_recv_single(struct virtproc_info *vrp, struct device *dev,
* We currently use fixed-sized buffers, so trivially sanitize
* the reported payload length.
*/
- if (len > RPMSG_BUF_SIZE ||
+ if (len > vrp->buf_size ||
msg->len > (len - sizeof(struct rpmsg_hdr))) {
dev_warn(dev, "inbound msg too big: (%d, %d)\n", len, msg->len);
return -EINVAL;
@@ -729,7 +731,7 @@ static int rpmsg_recv_single(struct virtproc_info *vrp, struct device *dev,
dev_warn(dev, "msg received with no recipient\n");

/* publish the real size of the buffer */
- sg_init_one(&sg, msg, RPMSG_BUF_SIZE);
+ sg_init_one(&sg, msg, vrp->buf_size);

/* add the buffer back to the remote processor's virtqueue */
err = virtqueue_add_inbuf(vrp->rvq, &sg, 1, msg, GFP_KERNEL);
@@ -886,7 +888,9 @@ static int rpmsg_probe(struct virtio_device *vdev)
else
vrp->num_bufs = MAX_RPMSG_NUM_BUFS;

- total_buf_space = vrp->num_bufs * RPMSG_BUF_SIZE;
+ vrp->buf_size = MAX_RPMSG_BUF_SIZE;
+
+ total_buf_space = vrp->num_bufs * vrp->buf_size;

/* allocate coherent memory for the buffers */
bufs_va = dma_alloc_coherent(vdev->dev.parent->parent,
@@ -909,9 +913,9 @@ static int rpmsg_probe(struct virtio_device *vdev)
/* set up the receive buffers */
for (i = 0; i < vrp->num_bufs / 2; i++) {
struct scatterlist sg;
- void *cpu_addr = vrp->rbufs + i * RPMSG_BUF_SIZE;
+ void *cpu_addr = vrp->rbufs + i * vrp->buf_size;

- sg_init_one(&sg, cpu_addr, RPMSG_BUF_SIZE);
+ sg_init_one(&sg, cpu_addr, vrp->buf_size);

err = virtqueue_add_inbuf(vrp->rvq, &sg, 1, cpu_addr,
GFP_KERNEL);
@@ -976,7 +980,7 @@ static int rpmsg_remove_device(struct device *dev, void *data)
static void rpmsg_remove(struct virtio_device *vdev)
{
struct virtproc_info *vrp = vdev->priv;
- size_t total_buf_space = vrp->num_bufs * RPMSG_BUF_SIZE;
+ size_t total_buf_space = vrp->num_bufs * vrp->buf_size;
int ret;

vdev->config->reset(vdev);
--
1.9.1