From: Nuno Sá Date: Tue, 7 Oct 2025 09:15:22 +0000 (+0100) Subject: iio: buffer-dma: support getting the DMA channel X-Git-Tag: v6.18~9^2~2^2~10 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=f9c198c3ccaf90a1a265fb2ffa8d4b093c3b0784;p=thirdparty%2Flinux.git 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 Signed-off-by: Nuno Sá Signed-off-by: Jonathan Cameron --- diff --git a/drivers/iio/buffer/industrialio-buffer-dma.c b/drivers/iio/buffer/industrialio-buffer-dma.c index ee294a775e8aa..7a7a9d37339bc 100644 --- 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); diff --git a/include/linux/iio/buffer-dma.h b/include/linux/iio/buffer-dma.h index 5eb66a3990021..4f33e6a39797d 100644 --- 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 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