Re: [PATCH 14/15] iio: buffer-dmaengine: Add support for cyclic buffers

[Alexandru Ardelean <ardeleanalex@gmail.com>]

On Mon, Nov 15, 2021 at 4:23 PM Paul Cercueil <paul@crapouillou.net> wrote:
>
> Handle the IIO_BUFFER_DMABUF_CYCLIC flag to support cyclic buffers.
>

Reviewed-by: Alexandru Ardelean <ardeleanalex@gmail.com>

> Signed-off-by: Paul Cercueil <paul@crapouillou.net>
> ---
>  drivers/iio/buffer/industrialio-buffer-dma.c      |  1 +
>  .../iio/buffer/industrialio-buffer-dmaengine.c    | 15 ++++++++++++---
>  include/linux/iio/buffer-dma.h                    |  3 +++
>  3 files changed, 16 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/iio/buffer/industrialio-buffer-dma.c b/drivers/iio/buffer/industrialio-buffer-dma.c
> index fb39054d8c15..6658f103ee17 100644
> --- a/drivers/iio/buffer/industrialio-buffer-dma.c
> +++ b/drivers/iio/buffer/industrialio-buffer-dma.c
> @@ -933,6 +933,7 @@ int iio_dma_buffer_enqueue_dmabuf(struct iio_buffer *buffer,
>         }
>
>         dma_block->bytes_used = iio_dmabuf->bytes_used ?: dma_block->size;
> +       dma_block->cyclic = iio_dmabuf->flags & IIO_BUFFER_DMABUF_CYCLIC;
>
>         switch (dma_block->state) {
>         case IIO_BLOCK_STATE_QUEUED:
> diff --git a/drivers/iio/buffer/industrialio-buffer-dmaengine.c b/drivers/iio/buffer/industrialio-buffer-dmaengine.c
> index 57a8b2e4ba3c..952e2160a11e 100644
> --- a/drivers/iio/buffer/industrialio-buffer-dmaengine.c
> +++ b/drivers/iio/buffer/industrialio-buffer-dmaengine.c
> @@ -81,9 +81,18 @@ static int iio_dmaengine_buffer_submit_block(struct iio_dma_buffer_queue *queue,
>         if (!block->bytes_used || block->bytes_used > max_size)
>                 return -EINVAL;
>
> -       desc = dmaengine_prep_slave_single(dmaengine_buffer->chan,
> -               block->phys_addr, block->bytes_used, dma_dir,
> -               DMA_PREP_INTERRUPT);
> +       if (block->cyclic) {
> +               desc = dmaengine_prep_dma_cyclic(dmaengine_buffer->chan,
> +                                                block->phys_addr,
> +                                                block->size,
> +                                                block->bytes_used,
> +                                                dma_dir, 0);
> +       } else {
> +               desc = dmaengine_prep_slave_single(dmaengine_buffer->chan,
> +                                                  block->phys_addr,
> +                                                  block->bytes_used, dma_dir,
> +                                                  DMA_PREP_INTERRUPT);
> +       }
>         if (!desc)
>                 return -ENOMEM;
>
> diff --git a/include/linux/iio/buffer-dma.h b/include/linux/iio/buffer-dma.h
> index 85e55fe35282..27639fdf7b54 100644
> --- a/include/linux/iio/buffer-dma.h
> +++ b/include/linux/iio/buffer-dma.h
> @@ -42,6 +42,7 @@ enum iio_block_state {
>   * @phys_addr: Physical address of the blocks memory
>   * @queue: Parent DMA buffer queue
>   * @state: Current state of the block
> + * @cyclic: True if this is a cyclic buffer
>   * @fileio: True if this buffer is used for fileio mode
>   * @dmabuf: Underlying DMABUF object
>   */
> @@ -65,6 +66,8 @@ struct iio_dma_buffer_block {
>          */
>         enum iio_block_state state;
>
> +       bool cyclic;
> +
>         bool fileio;
>         struct dma_buf *dmabuf;
>  };
> --
> 2.33.0
>