Messages in this thread Patch in this message | | | From | Sasha Levin <> | Subject | [PATCH AUTOSEL 4.14 31/72] media: platform: fcp: Set appropriate DMA parameters | Date | Mon, 8 Jun 2020 19:24:19 -0400 |
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From: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
[ Upstream commit dd844fb8e50b12e65bbdc5746c9876c6735500df ]
Enabling CONFIG_DMA_API_DEBUG=y and CONFIG_DMA_API_DEBUG_SG=y will enable extra validation on DMA operations ensuring that the size restraints are met.
When using the FCP in conjunction with the VSP1/DU, and display frames, the size of the DMA operations is larger than the default maximum segment size reported by the DMA core (64K). With the DMA debug enabled, this produces a warning such as the following:
"DMA-API: rcar-fcp fea27000.fcp: mapping sg segment longer than device claims to support [len=3145728] [max=65536]"
We have no specific limitation on the segment size which isn't already handled by the VSP1/DU which actually handles the DMA allcoations and buffer management, so define a maximum segment size of up to 4GB (a 32 bit mask).
Reported-by: Geert Uytterhoeven <geert+renesas@glider.be> Fixes: 7b49235e83b2 ("[media] v4l: Add Renesas R-Car FCP driver") Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> --- drivers/media/platform/rcar-fcp.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/drivers/media/platform/rcar-fcp.c b/drivers/media/platform/rcar-fcp.c index 2988031d285d..0047d144c932 100644 --- a/drivers/media/platform/rcar-fcp.c +++ b/drivers/media/platform/rcar-fcp.c @@ -12,6 +12,7 @@ */ #include <linux/device.h> +#include <linux/dma-mapping.h> #include <linux/list.h> #include <linux/module.h> #include <linux/mutex.h> @@ -24,6 +25,7 @@ struct rcar_fcp_device { struct list_head list; struct device *dev; + struct device_dma_parameters dma_parms; }; static LIST_HEAD(fcp_devices); @@ -139,6 +141,9 @@ static int rcar_fcp_probe(struct platform_device *pdev) fcp->dev = &pdev->dev; + fcp->dev->dma_parms = &fcp->dma_parms; + dma_set_max_seg_size(fcp->dev, DMA_BIT_MASK(32)); + pm_runtime_enable(&pdev->dev); mutex_lock(&fcp_lock); -- 2.25.1
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