Hi Tim,
Thank you for the patch.
On Thursday 19 March 2015 08:59:52 Tim Nordell wrote:
> When utilizing userptr buffers for output from the CCDC, the
> DMA subsystem maps buffers into the virtual address space.
> However, the DMA subsystem also has a configurable parameter
> for what the largest segment to allocate is out of the virtual
> address space as well.
>
> Since we need contiguous buffers for the memory space from the
> OMAP3 ISP's vantage point, we need to configure the segments
> to be at least as large as the largest buffer we expect.
>
> Signed-off-by: Tim Nordell <tim.nordell@xxxxxxxxxxx>
> ---
> drivers/media/platform/omap3isp/isp.c | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/drivers/media/platform/omap3isp/isp.c
> b/drivers/media/platform/omap3isp/isp.c index ead2d0d..906d3e5 100644
> --- a/drivers/media/platform/omap3isp/isp.c
> +++ b/drivers/media/platform/omap3isp/isp.c
> @@ -2170,6 +2170,20 @@ static int isp_attach_iommu(struct isp_device *isp)
> goto error;
> }
>
> + isp->dev->dma_parms = devm_kzalloc(isp->dev,
> + sizeof(*isp->dev->dma_parms), GFP_KERNEL);
> + if (!isp->dev->dma_parms) {
> + dev_err(isp->dev, "failed to allocate memory for dma_parms\n");
> + ret = -ENOMEM;
> + goto error;
> + }
How about adding a struct device_dma_parameters field in struct isp_device and
just assigning isp->dev->dma_parms = &isp->dma_parms ? This would get rid of
the separate allocation step.
> +
> + ret = dma_set_max_seg_size(isp->dev, SZ_32M);
There's no reason to limit the size to 32MB, you can use the full 4GB
addressable space.
> + if (ret < 0) {
> + dev_err(isp->dev, "failed to set max segment size for dma\n");
> + goto error;
> + }
> +
> return 0;
>
> error:
--
Regards,
Laurent Pinchart
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