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authorLinus Torvalds <torvalds@linux-foundation.org>2014-12-15 17:07:58 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2014-12-15 17:07:58 -0800
commit27cb8823e26cecd03c00d82dfb501f6c144b3445 (patch)
tree7f0db862866d342e8d80e8452eb651c6c4dbf3b6 /drivers
parent988adfdffdd43cfd841df734664727993076d7cb (diff)
parentb1b9891441fa33fd0d49b5cb3aa7f04bca1cc1db (diff)
downloadlinux-27cb8823e26cecd03c00d82dfb501f6c144b3445.tar.bz2
Merge tag 'rpmsg-3.19-next' of git://git.kernel.org/pub/scm/linux/kernel/git/ohad/rpmsg
Pull rpmsg update from Ohad Ben-Cohen: "A single patch from Suman Anna which makes rpmsg use less buffers when small vrings are being used" * tag 'rpmsg-3.19-next' of git://git.kernel.org/pub/scm/linux/kernel/git/ohad/rpmsg: rpmsg: use less buffers when vrings are small
Diffstat (limited to 'drivers')
-rw-r--r--drivers/rpmsg/virtio_rpmsg_bus.c44
1 files changed, 30 insertions, 14 deletions
diff --git a/drivers/rpmsg/virtio_rpmsg_bus.c b/drivers/rpmsg/virtio_rpmsg_bus.c
index b6135d4d54eb..92f6af6da699 100644
--- a/drivers/rpmsg/virtio_rpmsg_bus.c
+++ b/drivers/rpmsg/virtio_rpmsg_bus.c
@@ -41,6 +41,7 @@
* @svq: tx virtqueue
* @rbufs: kernel address of rx buffers
* @sbufs: kernel address of tx buffers
+ * @num_bufs: total number of buffers for rx and tx
* @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.
@@ -60,6 +61,7 @@ struct virtproc_info {
struct virtio_device *vdev;
struct virtqueue *rvq, *svq;
void *rbufs, *sbufs;
+ unsigned int num_bufs;
int last_sbuf;
dma_addr_t bufs_dma;
struct mutex tx_lock;
@@ -86,13 +88,14 @@ struct rpmsg_channel_info {
#define to_rpmsg_driver(d) container_of(d, struct rpmsg_driver, drv)
/*
- * We're allocating 512 buffers of 512 bytes for communications, and then
- * using the first 256 buffers for RX, and the last 256 buffers for TX.
+ * We're allocating buffers of 512 bytes each for communications. The
+ * number of buffers will be computed from the number of buffers supported
+ * by the vring, upto a maximum of 512 buffers (256 in each direction).
*
* Each buffer will have 16 bytes for the msg header and 496 bytes for
* the payload.
*
- * This will require a total space of 256KB for the buffers.
+ * This will utilize a maximum total space of 256KB for the buffers.
*
* We might also want to add support for user-provided buffers in time.
* This will allow bigger buffer size flexibility, and can also be used
@@ -102,9 +105,8 @@ struct rpmsg_channel_info {
* can change this without changing anything in the firmware of the remote
* processor.
*/
-#define RPMSG_NUM_BUFS (512)
+#define MAX_RPMSG_NUM_BUFS (512)
#define RPMSG_BUF_SIZE (512)
-#define RPMSG_TOTAL_BUF_SPACE (RPMSG_NUM_BUFS * RPMSG_BUF_SIZE)
/*
* Local addresses are dynamically allocated on-demand.
@@ -579,7 +581,7 @@ static void *get_a_tx_buf(struct virtproc_info *vrp)
* either pick the next unused tx buffer
* (half of our buffers are used for sending messages)
*/
- if (vrp->last_sbuf < RPMSG_NUM_BUFS / 2)
+ if (vrp->last_sbuf < vrp->num_bufs / 2)
ret = vrp->sbufs + RPMSG_BUF_SIZE * vrp->last_sbuf++;
/* or recycle a used one */
else
@@ -948,6 +950,7 @@ static int rpmsg_probe(struct virtio_device *vdev)
struct virtproc_info *vrp;
void *bufs_va;
int err = 0, i;
+ size_t total_buf_space;
vrp = kzalloc(sizeof(*vrp), GFP_KERNEL);
if (!vrp)
@@ -968,10 +971,22 @@ static int rpmsg_probe(struct virtio_device *vdev)
vrp->rvq = vqs[0];
vrp->svq = vqs[1];
+ /* we expect symmetric tx/rx vrings */
+ WARN_ON(virtqueue_get_vring_size(vrp->rvq) !=
+ virtqueue_get_vring_size(vrp->svq));
+
+ /* we need less buffers if vrings are small */
+ if (virtqueue_get_vring_size(vrp->rvq) < MAX_RPMSG_NUM_BUFS / 2)
+ vrp->num_bufs = virtqueue_get_vring_size(vrp->rvq) * 2;
+ else
+ vrp->num_bufs = MAX_RPMSG_NUM_BUFS;
+
+ total_buf_space = vrp->num_bufs * RPMSG_BUF_SIZE;
+
/* allocate coherent memory for the buffers */
bufs_va = dma_alloc_coherent(vdev->dev.parent->parent,
- RPMSG_TOTAL_BUF_SPACE,
- &vrp->bufs_dma, GFP_KERNEL);
+ total_buf_space, &vrp->bufs_dma,
+ GFP_KERNEL);
if (!bufs_va) {
err = -ENOMEM;
goto vqs_del;
@@ -984,10 +999,10 @@ static int rpmsg_probe(struct virtio_device *vdev)
vrp->rbufs = bufs_va;
/* and half is dedicated for TX */
- vrp->sbufs = bufs_va + RPMSG_TOTAL_BUF_SPACE / 2;
+ vrp->sbufs = bufs_va + total_buf_space / 2;
/* set up the receive buffers */
- for (i = 0; i < RPMSG_NUM_BUFS / 2; i++) {
+ for (i = 0; i < vrp->num_bufs / 2; i++) {
struct scatterlist sg;
void *cpu_addr = vrp->rbufs + i * RPMSG_BUF_SIZE;
@@ -1023,8 +1038,8 @@ static int rpmsg_probe(struct virtio_device *vdev)
return 0;
free_coherent:
- dma_free_coherent(vdev->dev.parent->parent, RPMSG_TOTAL_BUF_SPACE,
- bufs_va, vrp->bufs_dma);
+ dma_free_coherent(vdev->dev.parent->parent, total_buf_space,
+ bufs_va, vrp->bufs_dma);
vqs_del:
vdev->config->del_vqs(vrp->vdev);
free_vrp:
@@ -1042,6 +1057,7 @@ 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;
int ret;
vdev->config->reset(vdev);
@@ -1057,8 +1073,8 @@ static void rpmsg_remove(struct virtio_device *vdev)
vdev->config->del_vqs(vrp->vdev);
- dma_free_coherent(vdev->dev.parent->parent, RPMSG_TOTAL_BUF_SPACE,
- vrp->rbufs, vrp->bufs_dma);
+ dma_free_coherent(vdev->dev.parent->parent, total_buf_space,
+ vrp->rbufs, vrp->bufs_dma);
kfree(vrp);
}