Some stm32-dma consumers [1] rather use dma_get_slave_caps() to get
max_sg_burst of their DMA channel as dma_get_max_seg_size() is specific to
the DMA controller.
All stm32-dma channels have the same features so, don't need to implement
device_caps ops. Let dma_get_slave_caps() relies on dma_device
configuration.
That's why this patch sets dma_device max_sg_burst to the maximum segment
size, which is the maximum of data items that can be transferred without
software intervention.
[1] https://lore.kernel.org/lkml/[email protected]/
"media: stm32: dcmi: create a dma scatterlist based on DMA max_sg_burst value"
Signed-off-by: Amelie Delaunay <[email protected]>
---
drivers/dma/stm32-dma.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/dma/stm32-dma.c b/drivers/dma/stm32-dma.c
index 83a37a6955a3..d2365fab1b7a 100644
--- a/drivers/dma/stm32-dma.c
+++ b/drivers/dma/stm32-dma.c
@@ -1389,6 +1389,7 @@ static int stm32_dma_probe(struct platform_device *pdev)
dd->residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
dd->copy_align = DMAENGINE_ALIGN_32_BYTES;
dd->max_burst = STM32_DMA_MAX_BURST;
+ dd->max_sg_burst = STM32_DMA_ALIGNED_MAX_DATA_ITEMS;
dd->descriptor_reuse = true;
dd->dev = &pdev->dev;
INIT_LIST_HEAD(&dd->channels);
--
2.25.1
Hi,
thanks Amelie.
Tested-by: Alain Volmat <[email protected]>
Alain
On Mon, Jan 17, 2022 at 10:17:40AM +0100, Amelie Delaunay wrote:
> Some stm32-dma consumers [1] rather use dma_get_slave_caps() to get
> max_sg_burst of their DMA channel as dma_get_max_seg_size() is specific to
> the DMA controller.
> All stm32-dma channels have the same features so, don't need to implement
> device_caps ops. Let dma_get_slave_caps() relies on dma_device
> configuration.
> That's why this patch sets dma_device max_sg_burst to the maximum segment
> size, which is the maximum of data items that can be transferred without
> software intervention.
>
> [1] https://lore.kernel.org/lkml/[email protected]/
> "media: stm32: dcmi: create a dma scatterlist based on DMA max_sg_burst value"
>
> Signed-off-by: Amelie Delaunay <[email protected]>
> ---
> drivers/dma/stm32-dma.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/dma/stm32-dma.c b/drivers/dma/stm32-dma.c
> index 83a37a6955a3..d2365fab1b7a 100644
> --- a/drivers/dma/stm32-dma.c
> +++ b/drivers/dma/stm32-dma.c
> @@ -1389,6 +1389,7 @@ static int stm32_dma_probe(struct platform_device *pdev)
> dd->residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
> dd->copy_align = DMAENGINE_ALIGN_32_BYTES;
> dd->max_burst = STM32_DMA_MAX_BURST;
> + dd->max_sg_burst = STM32_DMA_ALIGNED_MAX_DATA_ITEMS;
> dd->descriptor_reuse = true;
> dd->dev = &pdev->dev;
> INIT_LIST_HEAD(&dd->channels);
> --
> 2.25.1
>
On 17-01-22, 10:17, Amelie Delaunay wrote:
> Some stm32-dma consumers [1] rather use dma_get_slave_caps() to get
> max_sg_burst of their DMA channel as dma_get_max_seg_size() is specific to
> the DMA controller.
> All stm32-dma channels have the same features so, don't need to implement
> device_caps ops. Let dma_get_slave_caps() relies on dma_device
> configuration.
> That's why this patch sets dma_device max_sg_burst to the maximum segment
> size, which is the maximum of data items that can be transferred without
> software intervention.
Applied, thanks
--
~Vinod