Re: [PATCH v2 2/6] [media] rockchip/rga: v4l2 m2m support
From: Laurent Pinchart
Date: Sat Jul 15 2017 - 05:42:43 EST
Thank you for the patch.
On Saturday 15 Jul 2017 14:58:36 Jacob Chen wrote:
> Rockchip RGA is a separate 2D raster graphic acceleration unit. It
> accelerates 2D graphics operations, such as point/line drawing, image
> scaling, rotation, BitBLT, alpha blending and image blur/sharpness.
> The drvier is mostly based on s5p-g2d v4l2 m2m driver.
> And supports various operations from the rendering pipeline.
> - copy
> - fast solid color fill
> - rotation
> - flip
> - alpha blending
I notice that you don't support the drawing operations. How do you plan to
support them later through the V4L2 M2M API ? I hate stating the obvious, but
wouldn't the DRM API be better fit for a graphic accelerator ?
Additionally, V4L2 M2M has one source and one destination. How do you
implement alpha blending in that case, which by definition requires at least
two sources ?
> The code in rga-hw.c is used to configure regs accroding to operations.
> The code in rga-buf.c is used to create private mmu table for RGA.
> The tables is stored in a list, and be removed when buffer is cleanup.
Looking at the implementation it seems to be a scatter-gather list, not an
MMU. Is that right ? Does the hardware documentation refer to it as an MMU ?
> Signed-off-by: Jacob Chen <jacob-chen@xxxxxxxxxx>
> drivers/media/platform/Kconfig | 11 +
> drivers/media/platform/Makefile | 2 +
> drivers/media/platform/rockchip-rga/Makefile | 3 +
> drivers/media/platform/rockchip-rga/rga-buf.c | 122 ++++
> drivers/media/platform/rockchip-rga/rga-hw.c | 652 ++++++++++++++++++
> drivers/media/platform/rockchip-rga/rga-hw.h | 437 ++++++++++++
> drivers/media/platform/rockchip-rga/rga.c | 958 +++++++++++++++++++++++
> drivers/media/platform/rockchip-rga/rga.h | 111 +++
> 8 files changed, 2296 insertions(+)
> create mode 100644 drivers/media/platform/rockchip-rga/Makefile
> create mode 100644 drivers/media/platform/rockchip-rga/rga-buf.c
> create mode 100644 drivers/media/platform/rockchip-rga/rga-hw.c
> create mode 100644 drivers/media/platform/rockchip-rga/rga-hw.h
> create mode 100644 drivers/media/platform/rockchip-rga/rga.c
> create mode 100644 drivers/media/platform/rockchip-rga/rga.h