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iio: buffer-dma: support getting the DMA channel 

Implement the .get_dma_dev() callback for DMA buffers by returning the
device that owns the DMA channel. This allows the core DMABUF
infrastructure to properly map DMA buffers using the correct device,
avoiding the need for bounce buffers on systems where memory is mapped
above the 32-bit range.

The function returns the DMA queue's device, which is the actual device
responsible for DMA operations in buffer-dma implementations.

Cc: stable@vger.kernel.org
Reviewed-by: David Lechner <dlechner@baylibre.com>
Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Nuno Sá 2025-10-07 10:15:22 +01:00 committed by Jonathan Cameron
parent a514bb109e
commit f9c198c3cc
2 changed files with 7 additions and 0 deletions
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6
drivers/iio/buffer/industrialio-buffer-dma.c
View File

@ -786,6 +786,12 @@ int iio_dma_buffer_enqueue_dmabuf(struct iio_buffer *buffer,
}
EXPORT_SYMBOL_NS_GPL(iio_dma_buffer_enqueue_dmabuf, "IIO_DMA_BUFFER");
struct device *iio_dma_buffer_get_dma_dev(struct iio_buffer *buffer)
{
return iio_buffer_to_queue(buffer)->dev;
}
EXPORT_SYMBOL_NS_GPL(iio_dma_buffer_get_dma_dev, "IIO_DMA_BUFFER");
void iio_dma_buffer_lock_queue(struct iio_buffer *buffer)
{
struct iio_dma_buffer_queue *queue = iio_buffer_to_queue(buffer);

1
include/linux/iio/buffer-dma.h
View File

@ -174,5 +174,6 @@ int iio_dma_buffer_enqueue_dmabuf(struct iio_buffer *buffer,
size_t size, bool cyclic);
void iio_dma_buffer_lock_queue(struct iio_buffer *buffer);
void iio_dma_buffer_unlock_queue(struct iio_buffer *buffer);
struct device *iio_dma_buffer_get_dma_dev(struct iio_buffer *buffer);
#endif