* [PATCH] dmaengine: stm32-dma: set dma_device max_sg_burst
@ 2022-01-17 9:17 Amelie Delaunay
2022-01-17 9:25 ` Alain Volmat
2022-02-15 5:42 ` Vinod Koul
0 siblings, 2 replies; 3+ messages in thread
From: Amelie Delaunay @ 2022-01-17 9:17 UTC (permalink / raw)
To: Vinod Koul, Maxime Coquelin, Alexandre Torgue
Cc: dmaengine, linux-stm32, linux-arm-kernel, linux-kernel,
Alain Volmat, Amelie Delaunay
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/20220110103739.118426-1-alain.volmat@foss.st.com/
"media: stm32: dcmi: create a dma scatterlist based on DMA max_sg_burst value"
Signed-off-by: Amelie Delaunay <amelie.delaunay@foss.st.com>
---
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
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] dmaengine: stm32-dma: set dma_device max_sg_burst
2022-01-17 9:17 [PATCH] dmaengine: stm32-dma: set dma_device max_sg_burst Amelie Delaunay
@ 2022-01-17 9:25 ` Alain Volmat
2022-02-15 5:42 ` Vinod Koul
1 sibling, 0 replies; 3+ messages in thread
From: Alain Volmat @ 2022-01-17 9:25 UTC (permalink / raw)
To: Amelie Delaunay
Cc: Vinod Koul, Maxime Coquelin, Alexandre Torgue, dmaengine,
linux-stm32, linux-arm-kernel, linux-kernel
Hi,
thanks Amelie.
Tested-by: Alain Volmat <alain.volmat@foss.st.com>
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/20220110103739.118426-1-alain.volmat@foss.st.com/
> "media: stm32: dcmi: create a dma scatterlist based on DMA max_sg_burst value"
>
> Signed-off-by: Amelie Delaunay <amelie.delaunay@foss.st.com>
> ---
> 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
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] dmaengine: stm32-dma: set dma_device max_sg_burst
2022-01-17 9:17 [PATCH] dmaengine: stm32-dma: set dma_device max_sg_burst Amelie Delaunay
2022-01-17 9:25 ` Alain Volmat
@ 2022-02-15 5:42 ` Vinod Koul
1 sibling, 0 replies; 3+ messages in thread
From: Vinod Koul @ 2022-02-15 5:42 UTC (permalink / raw)
To: Amelie Delaunay
Cc: Maxime Coquelin, Alexandre Torgue, dmaengine, linux-stm32,
linux-arm-kernel, linux-kernel, Alain Volmat
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
^ permalink raw reply [flat|nested] 3+ messages in thread
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2022-01-17 9:17 [PATCH] dmaengine: stm32-dma: set dma_device max_sg_burst Amelie Delaunay
2022-01-17 9:25 ` Alain Volmat
2022-02-15 5:42 ` Vinod Koul
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