6.17-stable review patch. If anyone has any objections, please let me know.
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From: Nuno Sá nuno.sa@analog.com
commit f9c198c3ccaf90a1a265fb2ffa8d4b093c3b0784 upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/iio/buffer/industrialio-buffer-dma.c | 6 ++++++ include/linux/iio/buffer-dma.h | 1 + 2 files changed, 7 insertions(+)
--- a/drivers/iio/buffer/industrialio-buffer-dma.c +++ b/drivers/iio/buffer/industrialio-buffer-dma.c @@ -786,6 +786,12 @@ out_end_signalling: } 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); --- a/include/linux/iio/buffer-dma.h +++ b/include/linux/iio/buffer-dma.h @@ -174,5 +174,6 @@ int iio_dma_buffer_enqueue_dmabuf(struct 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