Re: [PATCH v1 06/15] drm/mediatek: add memory mode for RDMA

CK Hu
2018-07-25T02:41:06Z

Hi, Stu:

On Tue, 2018-07-24 at 16:17 +0800, Stu Hsieh wrote:
> This patch add memory mode for RDMA
>
> If use RDMA to read data from memory, it should set memory mode to RDMA
>
> Signed-off-by: Stu Hsieh <stu.hsieh@mediatek.com>
> ---
> drivers/gpu/drm/mediatek/mtk_disp_rdma.c | 16 +++++++++++++++-
> 1 file changed, 15 insertions(+), 1 deletion(-)
>

[...]

> static inline struct mtk_disp_rdma *comp_to_rdma(struct mtk_ddp_comp *comp)
> @@ -111,7 +116,8 @@ static void mtk_rdma_start(struct mtk_ddp_comp *comp)
>
> static void mtk_rdma_stop(struct mtk_ddp_comp *comp)
> {
> - rdma_update_bits(comp, DISP_REG_RDMA_GLOBAL_CON, RDMA_ENGINE_EN, 0);
> + writel(RDMA_SOFT_RESET, comp->regs + DISP_REG_RDMA_GLOBAL_CON);
> + writel(0, comp->regs + DISP_REG_RDMA_GLOBAL_CON);

Without reset, what happen to dram mode? Why direct link mode need not
this reset?

> }
>
> static void mtk_rdma_config(struct mtk_ddp_comp *comp, unsigned int width,
> @@ -121,10 +127,18 @@ static void mtk_rdma_config(struct mtk_ddp_comp *comp, unsigned int width,
> unsigned int threshold;
> unsigned int reg;
> struct mtk_disp_rdma *rdma = comp_to_rdma(comp);
> + bool *rdma_memory_mode = comp->comp_mode;
>
> rdma_update_bits(comp, DISP_REG_RDMA_SIZE_CON_0, 0xfff, width);
> rdma_update_bits(comp, DISP_REG_RDMA_SIZE_CON_1, 0xfffff, height);
>
> + if (*rdma_memory_mode == true) {
> + rdma_update_bits(comp, DISP_REG_RDMA_SIZE_CON_0, 0xff0000,
> + MATRIX_INT_MTX_SEL_DEFAULT);
> + rdma_update_bits(comp, DISP_REG_RDMA_GLOBAL_CON,
> + RDMA_MODE_MEMORY, RDMA_MODE_MEMORY);
> + }
> +

I would like this to be a kind of 'layer' config. In some SoC, one layer
of OVL could switch to direct link input or dram input. So I think it's
better to move this setting into some layer interface.

Regards,
CK

> /*
> * Enable FIFO underflow since DSI and DPI can't be blocked.
> * Keep the FIFO pseudo size reset default of 8 KiB. Set the