| Message ID | 20210212102021.47276-6-alexandru.ardelean@analog.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | iio: buffer: add output buffer and cyclic mode | expand |
On Fri, 12 Feb 2021 12:20:21 +0200 Alexandru Ardelean <alexandru.ardelean@analog.com> wrote: > From: Lars-Peter Clausen <lars@metafoo.de> > > This change adds support for cyclic DMA transfers using the IIO buffer DMA > infrastructure. > To do this, userspace must set the IIO_BUFFER_BLOCK_FLAG_CYCLIC flag on the > block when enqueueing them via the ENQUEUE_BLOCK ioctl(). We should have more than that in the way of documentation! What is the dataflow that we end up with as a result of this? Jonathan > > Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> > Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com> > --- > .../buffer/industrialio-buffer-dmaengine.c | 24 ++++++++++++------- > include/uapi/linux/iio/buffer.h | 1 + > 2 files changed, 17 insertions(+), 8 deletions(-) > > diff --git a/drivers/iio/buffer/industrialio-buffer-dmaengine.c b/drivers/iio/buffer/industrialio-buffer-dmaengine.c > index 013cc7c1ecf4..94c93a636ad4 100644 > --- a/drivers/iio/buffer/industrialio-buffer-dmaengine.c > +++ b/drivers/iio/buffer/industrialio-buffer-dmaengine.c > @@ -82,14 +82,22 @@ static int iio_dmaengine_buffer_submit_block(struct iio_dma_buffer_queue *queue, > > direction = dmaengine_buffer->is_tx ? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM; > > - desc = dmaengine_prep_slave_single(dmaengine_buffer->chan, > - block->phys_addr, block->block.bytes_used, direction, > - DMA_PREP_INTERRUPT); > - if (!desc) > - return -ENOMEM; > - > - desc->callback_result = iio_dmaengine_buffer_block_done; > - desc->callback_param = block; > + if (block->block.flags & IIO_BUFFER_BLOCK_FLAG_CYCLIC) { > + desc = dmaengine_prep_dma_cyclic(dmaengine_buffer->chan, > + block->phys_addr, block->block.bytes_used, > + block->block.bytes_used, direction, 0); > + if (!desc) > + return -ENOMEM; > + } else { > + desc = dmaengine_prep_slave_single(dmaengine_buffer->chan, > + block->phys_addr, block->block.bytes_used, direction, > + DMA_PREP_INTERRUPT); > + if (!desc) > + return -ENOMEM; > + > + desc->callback_result = iio_dmaengine_buffer_block_done; > + desc->callback_param = block; > + } > > cookie = dmaengine_submit(desc); > if (dma_submit_error(cookie)) > diff --git a/include/uapi/linux/iio/buffer.h b/include/uapi/linux/iio/buffer.h > index 70ad3aea01ea..0e0c95f1c38b 100644 > --- a/include/uapi/linux/iio/buffer.h > +++ b/include/uapi/linux/iio/buffer.h > @@ -13,6 +13,7 @@ struct iio_buffer_block_alloc_req { > }; > > #define IIO_BUFFER_BLOCK_FLAG_TIMESTAMP_VALID (1 << 0) > +#define IIO_BUFFER_BLOCK_FLAG_CYCLIC (1 << 1) > > struct iio_buffer_block { > __u32 id;
diff --git a/drivers/iio/buffer/industrialio-buffer-dmaengine.c b/drivers/iio/buffer/industrialio-buffer-dmaengine.c index 013cc7c1ecf4..94c93a636ad4 100644 --- a/drivers/iio/buffer/industrialio-buffer-dmaengine.c +++ b/drivers/iio/buffer/industrialio-buffer-dmaengine.c @@ -82,14 +82,22 @@ static int iio_dmaengine_buffer_submit_block(struct iio_dma_buffer_queue *queue, direction = dmaengine_buffer->is_tx ? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM; - desc = dmaengine_prep_slave_single(dmaengine_buffer->chan, - block->phys_addr, block->block.bytes_used, direction, - DMA_PREP_INTERRUPT); - if (!desc) - return -ENOMEM; - - desc->callback_result = iio_dmaengine_buffer_block_done; - desc->callback_param = block; + if (block->block.flags & IIO_BUFFER_BLOCK_FLAG_CYCLIC) { + desc = dmaengine_prep_dma_cyclic(dmaengine_buffer->chan, + block->phys_addr, block->block.bytes_used, + block->block.bytes_used, direction, 0); + if (!desc) + return -ENOMEM; + } else { + desc = dmaengine_prep_slave_single(dmaengine_buffer->chan, + block->phys_addr, block->block.bytes_used, direction, + DMA_PREP_INTERRUPT); + if (!desc) + return -ENOMEM; + + desc->callback_result = iio_dmaengine_buffer_block_done; + desc->callback_param = block; + } cookie = dmaengine_submit(desc); if (dma_submit_error(cookie)) diff --git a/include/uapi/linux/iio/buffer.h b/include/uapi/linux/iio/buffer.h index 70ad3aea01ea..0e0c95f1c38b 100644 --- a/include/uapi/linux/iio/buffer.h +++ b/include/uapi/linux/iio/buffer.h @@ -13,6 +13,7 @@ struct iio_buffer_block_alloc_req { }; #define IIO_BUFFER_BLOCK_FLAG_TIMESTAMP_VALID (1 << 0) +#define IIO_BUFFER_BLOCK_FLAG_CYCLIC (1 << 1) struct iio_buffer_block { __u32 id;