From 61f136211d06332f1c13766e321eb779b4d02ad6 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Nuno=20S=C3=A1?= Date: Tue, 7 Oct 2025 10:15:22 +0100 Subject: [PATCH] iio: buffer-dma: support getting the DMA channel MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Nuno Sá Signed-off-by: Jonathan Cameron Signed-off-by: Greg Kroah-Hartman --- drivers/iio/buffer/industrialio-buffer-dma.c | 6 ++++++ include/linux/iio/buffer-dma.h | 1 + 2 files changed, 7 insertions(+) diff --git a/drivers/iio/buffer/industrialio-buffer-dma.c b/drivers/iio/buffer/industrialio-buffer-dma.c index dbde1443d6ed..1f547de4bcc2 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 5eb66a399002..4f33e6a39797 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