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

[Paul Cercueil]

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 <p...@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