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Commit 27cb8823 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

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
parents 988adfdf b1b98914

drivers/rpmsg/virtio_rpmsg_bus.c

+30 −14
Original line number Diff line number Diff line
@@ -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;
@@ -1023,7 +1038,7 @@ static int rpmsg_probe(struct virtio_device *vdev) 
	return 0;



free_coherent:

	dma_free_coherent(vdev->dev.parent->parent, RPMSG_TOTAL_BUF_SPACE,

	dma_free_coherent(vdev->dev.parent->parent, total_buf_space,

			  bufs_va, vrp->bufs_dma);

vqs_del:

	vdev->config->del_vqs(vrp->vdev);
@@ -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);
@@ -1057,7 +1073,7 @@ 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,

	dma_free_coherent(vdev->dev.parent->parent, total_buf_space,

			  vrp->rbufs, vrp->bufs_dma);



	kfree(vrp);