Hello Marek,
On 02/14/2017 04:52 AM, Marek Szyprowski wrote:
> It turned out that all versions of MFC v6+ hardware doesn't have a strict
> requirement for ALL buffers to be allocated on higher addresses than the
> firmware base like it was documented for MFC v5. This requirement is true
> only for the device and per-context buffers. All video data buffers can be
> allocated anywhere for all MFC v6+ versions. Basing on this fact, the
> special DMA configuration based on two reserved memory regions is not
> really needed for MFC v6+ devices, because the memory requirements for the
> firmware, device and per-context buffers can be fulfilled by the simple
> probe-time pre-allocated block allocator instroduced in previous patch.
s/instroduced/introduced
>
> This patch enables support for such pre-allocated block based allocator
> always for MFC v6+ devices. Due to the limitations of the memory management
> subsystem the largest supported size of the pre-allocated buffer when no
> CMA (Contiguous Memory Allocator) is enabled is 4MiB.
>
> This patch also removes the requirement to provide two reserved memory
> regions for MFC v6+ devices in device tree. Now the driver is fully
> functional without them.
>
Great!
> Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
> ---
The patch looks good to me though and it works on my tests,
I've just one comment below.
Reviewed-by: Javier Martinez Canillas <javier@xxxxxxxxxxxxxxx>
Tested-by: Javier Martinez Canillas <javier@xxxxxxxxxxxxxxx>
> Documentation/devicetree/bindings/media/s5p-mfc.txt | 2 +-
> drivers/media/platform/s5p-mfc/s5p_mfc.c | 9 ++++++---
> 2 files changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/media/s5p-mfc.txt b/Documentation/devicetree/bindings/media/s5p-mfc.txt
> index 2c901286d818..d3404b5d4d17 100644
> --- a/Documentation/devicetree/bindings/media/s5p-mfc.txt
> +++ b/Documentation/devicetree/bindings/media/s5p-mfc.txt
> @@ -28,7 +28,7 @@ Optional properties:
> - memory-region : from reserved memory binding: phandles to two reserved
> memory regions, first is for "left" mfc memory bus interfaces,
> second if for the "right" mfc memory bus, used when no SYSMMU
> - support is available
> + support is available; used only by MFC v5 present in Exynos4 SoCs
>
> Obsolete properties:
> - samsung,mfc-r, samsung,mfc-l : support removed, please use memory-region
> diff --git a/drivers/media/platform/s5p-mfc/s5p_mfc.c b/drivers/media/platform/s5p-mfc/s5p_mfc.c
> index 8fc6fe4ba087..36f0aec2a1b3 100644
> --- a/drivers/media/platform/s5p-mfc/s5p_mfc.c
> +++ b/drivers/media/platform/s5p-mfc/s5p_mfc.c
> @@ -1178,9 +1178,12 @@ static void s5p_mfc_unconfigure_2port_memory(struct s5p_mfc_dev *mfc_dev)
> static int s5p_mfc_configure_common_memory(struct s5p_mfc_dev *mfc_dev)
> {
> struct device *dev = &mfc_dev->plat_dev->dev;
> - unsigned long mem_size = SZ_8M;
> + unsigned long mem_size = SZ_4M;
> unsigned int bitmap_size;
>
> + if (IS_ENABLED(CONFIG_DMA_CMA) || exynos_is_iommu_available(dev))
> + mem_size = SZ_8M;
> +
> if (mfc_mem_size)
> mem_size = memparse(mfc_mem_size, NULL);
>
The driver allows the user to set mem_size > SZ_4M using the s5p_mfc.mem
parameter even when CMA ins't enabled and IOMMU isn't available. Maybe it
should fail early instead and notify the user what's missing?
Best regards,
--
Javier Martinez Canillas
Open Source Group
Samsung Research America
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