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Commit dd844fb8 authored by Kieran Bingham's avatar Kieran Bingham Committed by Mauro Carvalho Chehab
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media: platform: fcp: Set appropriate DMA parameters



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: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
Fixes: 7b49235e ("[media] v4l: Add Renesas R-Car FCP driver")
Signed-off-by: default avatarKieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Reviewed-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
Tested-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: default avatarHans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab+huawei@kernel.org>
parent dba36134
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