[PATCH v2 03/12] iio: buffer-dmaengine: Support specifying buffer direction

Paul Cercueil
2022-02-07T13:16:56Z

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.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Reviewed-by: Alexandru Ardelean <ardeleanalex@gmail.com>
---
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
--
2.34.1