On 12/07/2016 02:35 PM, Loic Pallardy wrote:
> Rpmsg is allocating buffer one dedicated communication link
> with some specificity like number of buffers, size of one buffer...
> These characteristics should be shared with remote coprocessor to
> guarantee communication link coherency.
>
> Proposal is to update rpmsg configuration fields in coprocessor firmware
> resource table if it exists.
>
> This is possible thanks to virtio set interface which allows to update
> cfg fields of struct fw_rsc_vdev.
>
> Signed-off-by: Loic Pallardy <loic.pallardy@xxxxxx>
> ---
> drivers/rpmsg/virtio_rpmsg_bus.c | 25 +++++++++++++++++++++++++
> 1 file changed, 25 insertions(+)
>
> diff --git a/drivers/rpmsg/virtio_rpmsg_bus.c b/drivers/rpmsg/virtio_rpmsg_bus.c
> index b12fe2a..5527b65 100644
> --- a/drivers/rpmsg/virtio_rpmsg_bus.c
> +++ b/drivers/rpmsg/virtio_rpmsg_bus.c
> @@ -924,6 +924,23 @@ static int virtio_rpmsg_get_config(struct virtio_device *vdev)
>
> }
>
> +static void virtio_rpmsg_set_config(struct virtio_device *vdev)
> +{
> + struct virtio_rpmsg_cfg virtio_cfg;
> + struct virtproc_info *vrp = vdev->priv;
> +
> + /* fill virtio_cfg struct */
> + memset(&virtio_cfg, 0, sizeof(virtio_cfg));
> + virtio_cfg.id = VIRTIO_ID_RPMSG;
> + virtio_cfg.da = vrp->bufs_dma;
Hmm, I would expect this to fail if the device was behind an IOMMU.
regards
Suman
> + virtio_cfg.pa = vrp->bufs_dma;
> + virtio_cfg.len = vrp->num_bufs * vrp->buf_size;
> + virtio_cfg.buf_size = vrp->buf_size;
> +
> + vdev->config->set(vdev, RPMSG_CONFIG_OFFSET, &virtio_cfg,
> + sizeof(virtio_cfg));
> +}
> +
> static int rpmsg_probe(struct virtio_device *vdev)
> {
> vq_callback_t *vq_cbs[] = { rpmsg_recv_done, rpmsg_xmit_done };
> @@ -934,6 +951,7 @@ static int rpmsg_probe(struct virtio_device *vdev)
> int err = 0, i;
> size_t total_buf_space;
> bool notify;
> + bool has_cfg = false;
>
> vrp = kzalloc(sizeof(*vrp), GFP_KERNEL);
> if (!vrp)
> @@ -973,6 +991,9 @@ static int rpmsg_probe(struct virtio_device *vdev)
> if (err < 0)
> goto free_vrp;
>
> + if (err)
> + has_cfg = true;
> +
> /* Allocate buffer if none provided by low level platform driver */
> if (!vrp->ext_buffer) {
> total_buf_space = vrp->num_bufs * vrp->buf_size;
> @@ -993,6 +1014,10 @@ static int rpmsg_probe(struct virtio_device *vdev)
>
> /* and half is dedicated for TX */
> vrp->sbufs = bufs_va + total_buf_space / 2;
> +
> + /* Notify configuration to coprocessor */
> + if (has_cfg)
> + virtio_rpmsg_set_config(vdev);
> }
>
> /* set up the receive buffers */
>
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