[PATCH 05/15] iio: buffer-dmaengine: Support specifying buffer direction

[Alexandru Ardelean]

On Mon, Nov 15, 2021 at 4:20 PM Paul Cercueil <paul at crapouillou.net> wrote:
>
> Update the devm_iio_dmaengine_buffer_setup() function to support
> specifying the buffer direction.
>
> Update the iio_dmaengine_buffer_submit() function to handle input
> buffers as well as output buffers.
>


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


> Signed-off-by: Paul Cercueil <paul at crapouillou.net>
> ---
>  drivers/iio/adc/adi-axi-adc.c                 |  3 ++-
>  .../buffer/industrialio-buffer-dmaengine.c    | 24 +++++++++++++++----
>  include/linux/iio/buffer-dmaengine.h          |  5 +++-
>  3 files changed, 25 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/iio/adc/adi-axi-adc.c b/drivers/iio/adc/adi-axi-adc.c
> index a73e3c2d212f..0a6f2c32b1b9 100644
> --- a/drivers/iio/adc/adi-axi-adc.c
> +++ b/drivers/iio/adc/adi-axi-adc.c
> @@ -113,7 +113,8 @@ static int adi_axi_adc_config_dma_buffer(struct device *dev,
>                 dma_name = "rx";
>
>         return devm_iio_dmaengine_buffer_setup(indio_dev->dev.parent,
> -                                              indio_dev, dma_name);
> +                                              indio_dev, dma_name,
> +                                              IIO_BUFFER_DIRECTION_IN);
>  }
>
>  static int adi_axi_adc_read_raw(struct iio_dev *indio_dev,
> diff --git a/drivers/iio/buffer/industrialio-buffer-dmaengine.c b/drivers/iio/buffer/industrialio-buffer-dmaengine.c
> index f8ce26a24c57..ac26b04aa4a9 100644
> --- a/drivers/iio/buffer/industrialio-buffer-dmaengine.c
> +++ b/drivers/iio/buffer/industrialio-buffer-dmaengine.c
> @@ -64,14 +64,25 @@ static int iio_dmaengine_buffer_submit_block(struct iio_dma_buffer_queue *queue,
>         struct dmaengine_buffer *dmaengine_buffer =
>                 iio_buffer_to_dmaengine_buffer(&queue->buffer);
>         struct dma_async_tx_descriptor *desc;
> +       enum dma_transfer_direction dma_dir;
> +       size_t max_size;
>         dma_cookie_t cookie;
>
> -       block->bytes_used = min(block->size, dmaengine_buffer->max_size);
> -       block->bytes_used = round_down(block->bytes_used,
> -                       dmaengine_buffer->align);
> +       max_size = min(block->size, dmaengine_buffer->max_size);
> +       max_size = round_down(max_size, dmaengine_buffer->align);
> +
> +       if (queue->buffer.direction == IIO_BUFFER_DIRECTION_IN) {
> +               block->bytes_used = max_size;
> +               dma_dir = DMA_DEV_TO_MEM;
> +       } else {
> +               dma_dir = DMA_MEM_TO_DEV;
> +       }
> +
> +       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_DEV_TO_MEM,
> +               block->phys_addr, block->bytes_used, dma_dir,
>                 DMA_PREP_INTERRUPT);
>         if (!desc)
>                 return -ENOMEM;
> @@ -275,7 +286,8 @@ static struct iio_buffer *devm_iio_dmaengine_buffer_alloc(struct device *dev,
>   */
>  int devm_iio_dmaengine_buffer_setup(struct device *dev,
>                                     struct iio_dev *indio_dev,
> -                                   const char *channel)
> +                                   const char *channel,
> +                                   enum iio_buffer_direction dir)
>  {
>         struct iio_buffer *buffer;
>
> @@ -286,6 +298,8 @@ int devm_iio_dmaengine_buffer_setup(struct device *dev,
>
>         indio_dev->modes |= INDIO_BUFFER_HARDWARE;
>
> +       buffer->direction = dir;
> +
>         return iio_device_attach_buffer(indio_dev, buffer);
>  }
>  EXPORT_SYMBOL_GPL(devm_iio_dmaengine_buffer_setup);
> diff --git a/include/linux/iio/buffer-dmaengine.h b/include/linux/iio/buffer-dmaengine.h
> index 5c355be89814..538d0479cdd6 100644
> --- a/include/linux/iio/buffer-dmaengine.h
> +++ b/include/linux/iio/buffer-dmaengine.h
> @@ -7,11 +7,14 @@
>  #ifndef __IIO_DMAENGINE_H__
>  #define __IIO_DMAENGINE_H__
>
> +#include <linux/iio/buffer.h>
> +
>  struct iio_dev;
>  struct device;
>
>  int devm_iio_dmaengine_buffer_setup(struct device *dev,
>                                     struct iio_dev *indio_dev,
> -                                   const char *channel);
> +                                   const char *channel,
> +                                   enum iio_buffer_direction dir);
>
>  #endif
> --
> 2.33.0
>