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| author |   Kieran Bingham <kieran.bingham+renesas@ideasonboard.com> | 2020-04-07 17:44:17 +0200 |
|---|---|---|
| committer |   Mauro Carvalho Chehab <mchehab+huawei@kernel.org> | 2020-04-21 13:33:50 +0200 |
| commit | dd844fb8e50b12e65bbdc5746c9876c6735500df (patch) | |
| tree | 85461f3ca973435a16d2b60af842915453e7ba98 /drivers/media/platform | |
| parent | media: staging: rkisp1: remove TODO item - uapi structs compatibility (diff) | |
| download | wireguard-linux-dd844fb8e50b12e65bbdc5746c9876c6735500df.tar.xz wireguard-linux-dd844fb8e50b12e65bbdc5746c9876c6735500df.zip | |
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: 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>
Diffstat (limited to 'drivers/media/platform')
| -rw-r--r-- | drivers/media/platform/rcar-fcp.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/media/platform/rcar-fcp.c b/drivers/media/platform/rcar-fcp.c index 43c78620c9d8..5c6b00737fe7 100644 --- a/drivers/media/platform/rcar-fcp.c +++ b/drivers/media/platform/rcar-fcp.c @@ -8,6 +8,7 @@ */ #include <linux/device.h> +#include <linux/dma-mapping.h> #include <linux/list.h> #include <linux/module.h> #include <linux/mod_devicetable.h> @@ -21,6 +22,7 @@ struct rcar_fcp_device { struct list_head list; struct device *dev; + struct device_dma_parameters dma_parms; }; static LIST_HEAD(fcp_devices); @@ -136,6 +138,9 @@ 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); |