Re: [PATCH] drm/msm/dpu: add support for dither block in display

From: Rob Clark
Date: Wed Jun 24 2020 - 16:25:18 EST

On Wed, Jun 24, 2020 at 4:57 AM Kalyan Thota <kalyan_t@xxxxxxxxxxxxxx> wrote:
>
> This change enables dither block for primary interface
> in display.
>
> Enabled for 6bpc in the current version.
>
> Signed-off-by: Kalyan Thota <kalyan_t@xxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 45 +++++++++++++++++
> drivers/gpu/drm/msm/disp/dpu1/dpu_hw_pingpong.c | 66 +++++++++++++++++++++----
> drivers/gpu/drm/msm/disp/dpu1/dpu_hw_pingpong.h | 28 +++++++++++
> 3 files changed, 130 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> index 63976dc..26e870a 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> @@ -208,6 +208,42 @@ struct dpu_encoder_virt {
>
> #define to_dpu_encoder_virt(x) container_of(x, struct dpu_encoder_virt, base)
>
> +static u32 dither_matrix[DITHER_MATRIX_SZ] = {
> + 15, 7, 13, 5, 3, 11, 1, 9, 12, 4, 14, 6, 0, 8, 2, 10
> +};
> +
> +static void _dpu_encoder_setup_dither(struct dpu_encoder_phys *phys)
> +{
> + struct dpu_hw_dither_cfg dither_cfg = { 0 };
> + struct drm_display_info *info;
> +
> + if (!phys || !phys->connector || !phys->hw_pp ||
> + !phys->hw_pp->ops.setup_dither)
> + return;

it looks like other than phys->hw_pp->ops.setup_dither, you shouldn't
need to check most of these conditions.

> +
> + info = &phys->connector->display_info;
> + if (!info)

and definitely not this one

> + return;
> +
> + switch (phys->connector->display_info.bpc) {
> + case 6:
> + dither_cfg.c0_bitdepth = 6;
> + dither_cfg.c1_bitdepth = 6;
> + dither_cfg.c2_bitdepth = 6;
> + dither_cfg.c3_bitdepth = 6;
> + dither_cfg.temporal_en = 0;
> + break;
> + default:
> + phys->hw_pp->ops.setup_dither(phys->hw_pp, NULL);
> + return;
> + }
> +
> + memcpy(&dither_cfg.matrix, dither_matrix,
> + sizeof(u32) * DITHER_MATRIX_SZ);
> +
> + phys->hw_pp->ops.setup_dither(phys->hw_pp, &dither_cfg);
> +}
> +
> void dpu_encoder_helper_report_irq_timeout(struct dpu_encoder_phys *phys_enc,
> enum dpu_intr_idx intr_idx)
> {
> @@ -1082,6 +1118,7 @@ static void _dpu_encoder_virt_enable_helper(struct drm_encoder *drm_enc)
> struct dpu_encoder_virt *dpu_enc = NULL;
> struct msm_drm_private *priv;
> struct dpu_kms *dpu_kms;
> + int i;
>
> if (!drm_enc || !drm_enc->dev) {
> DPU_ERROR("invalid parameters\n");
> @@ -1104,6 +1141,14 @@ static void _dpu_encoder_virt_enable_helper(struct drm_encoder *drm_enc)
> dpu_kms->catalog);
>
> _dpu_encoder_update_vsync_source(dpu_enc, &dpu_enc->disp_info);
> +
> + if (dpu_enc->disp_info.intf_type == DRM_MODE_ENCODER_DSI) {
> + for (i = 0; i < dpu_enc->num_phys_encs; i++) {
> + struct dpu_encoder_phys *phys = dpu_enc->phys_encs[i];
> +
> + _dpu_encoder_setup_dither(phys);
> + }
> + }
> }
>
> void dpu_encoder_virt_runtime_resume(struct drm_encoder *drm_enc)
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_pingpong.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_pingpong.c
> index d110a40..cf7603d 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_pingpong.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_pingpong.c
> @@ -28,6 +28,16 @@
> #define PP_FBC_BUDGET_CTL 0x038
> #define PP_FBC_LOSSY_MODE 0x03C
>
> +#define PP_DITHER_EN 0x000
> +#define PP_DITHER_BITDEPTH 0x004
> +#define PP_DITHER_MATRIX 0x008
> +
> +#define DITHER_DEPTH_MAP_INDEX 9
> +
> +static u32 dither_depth_map[DITHER_DEPTH_MAP_INDEX] = {
> + 0, 0, 0, 0, 0, 0, 0, 1, 2
> +};
> +
> static const struct dpu_pingpong_cfg *_pingpong_offset(enum dpu_pingpong pp,
> const struct dpu_mdss_cfg *m,
> void __iomem *addr,
> @@ -49,6 +59,40 @@ static const struct dpu_pingpong_cfg *_pingpong_offset(enum dpu_pingpong pp,
> return ERR_PTR(-EINVAL);
> }
>
> +static void dpu_hw_pp_setup_dither(struct dpu_hw_pingpong *pp,
> + struct dpu_hw_dither_cfg *cfg)
> +{
> + struct dpu_hw_blk_reg_map *c;
> + u32 i, base, data = 0;
> +
> + if (!pp)
> + return;

can this ever be NULL.. at least currently you are checking this both
here and in _dpu_encoder_setup_dither()

BR,
-R

> +
> + c = &pp->hw;
> + base = pp->caps->sblk->dither.base;
> + if (!cfg) {
> + DPU_REG_WRITE(c, base + PP_DITHER_EN, 0);
> + return;
> + }
> +
> + data = dither_depth_map[cfg->c0_bitdepth] & REG_MASK(2);
> + data |= (dither_depth_map[cfg->c1_bitdepth] & REG_MASK(2)) << 2;
> + data |= (dither_depth_map[cfg->c2_bitdepth] & REG_MASK(2)) << 4;
> + data |= (dither_depth_map[cfg->c3_bitdepth] & REG_MASK(2)) << 6;
> + data |= (cfg->temporal_en) ? (1 << 8) : 0;
> +
> + DPU_REG_WRITE(c, base + PP_DITHER_BITDEPTH, data);
> +
> + for (i = 0; i < DITHER_MATRIX_SZ - 3; i += 4) {
> + data = (cfg->matrix[i] & REG_MASK(4)) |
> + ((cfg->matrix[i + 1] & REG_MASK(4)) << 4) |
> + ((cfg->matrix[i + 2] & REG_MASK(4)) << 8) |
> + ((cfg->matrix[i + 3] & REG_MASK(4)) << 12);
> + DPU_REG_WRITE(c, base + PP_DITHER_MATRIX + i, data);
> + }
> + DPU_REG_WRITE(c, base + PP_DITHER_EN, 1);
> +}
> +
> static int dpu_hw_pp_setup_te_config(struct dpu_hw_pingpong *pp,
> struct dpu_hw_tear_check *te)
> {
> @@ -180,15 +224,19 @@ static u32 dpu_hw_pp_get_line_count(struct dpu_hw_pingpong *pp)
> return line;
> }
>
> -static void _setup_pingpong_ops(struct dpu_hw_pingpong_ops *ops,
> - const struct dpu_pingpong_cfg *hw_cap)
> +static void _setup_pingpong_ops(struct dpu_hw_pingpong *c,
> + unsigned long features)
> {
> - ops->setup_tearcheck = dpu_hw_pp_setup_te_config;
> - ops->enable_tearcheck = dpu_hw_pp_enable_te;
> - ops->connect_external_te = dpu_hw_pp_connect_external_te;
> - ops->get_vsync_info = dpu_hw_pp_get_vsync_info;
> - ops->poll_timeout_wr_ptr = dpu_hw_pp_poll_timeout_wr_ptr;
> - ops->get_line_count = dpu_hw_pp_get_line_count;
> + c->ops.setup_tearcheck = dpu_hw_pp_setup_te_config;
> + c->ops.enable_tearcheck = dpu_hw_pp_enable_te;
> + c->ops.connect_external_te = dpu_hw_pp_connect_external_te;
> + c->ops.get_vsync_info = dpu_hw_pp_get_vsync_info;
> + c->ops.poll_timeout_wr_ptr = dpu_hw_pp_poll_timeout_wr_ptr;
> + c->ops.get_line_count = dpu_hw_pp_get_line_count;
> +
> + if (test_bit(DPU_PINGPONG_DITHER, &features) &&
> + IS_SC7180_TARGET(c->hw.hwversion))
> + c->ops.setup_dither = dpu_hw_pp_setup_dither;
> };
>
> static struct dpu_hw_blk_ops dpu_hw_ops;
> @@ -212,7 +260,7 @@ struct dpu_hw_pingpong *dpu_hw_pingpong_init(enum dpu_pingpong idx,
>
> c->idx = idx;
> c->caps = cfg;
> - _setup_pingpong_ops(&c->ops, c->caps);
> + _setup_pingpong_ops(c, c->caps->features);
>
> dpu_hw_blk_init(&c->base, DPU_HW_BLK_PINGPONG, idx, &dpu_hw_ops);
>
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_pingpong.h b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_pingpong.h
> index d73cb73..065996b 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_pingpong.h
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_pingpong.h
> @@ -10,6 +10,8 @@
> #include "dpu_hw_util.h"
> #include "dpu_hw_blk.h"
>
> +#define DITHER_MATRIX_SZ 16
> +
> struct dpu_hw_pingpong;
>
> struct dpu_hw_tear_check {
> @@ -35,6 +37,26 @@ struct dpu_hw_pp_vsync_info {
> };
>
> /**
> + * struct dpu_hw_dither_cfg - dither feature structure
> + * @flags: for customizing operations
> + * @temporal_en: temperal dither enable
> + * @c0_bitdepth: c0 component bit depth
> + * @c1_bitdepth: c1 component bit depth
> + * @c2_bitdepth: c2 component bit depth
> + * @c3_bitdepth: c2 component bit depth
> + * @matrix: dither strength matrix
> + */
> +struct dpu_hw_dither_cfg {
> + u64 flags;
> + u32 temporal_en;
> + u32 c0_bitdepth;
> + u32 c1_bitdepth;
> + u32 c2_bitdepth;
> + u32 c3_bitdepth;
> + u32 matrix[DITHER_MATRIX_SZ];
> +};
> +
> +/**
> *
> * struct dpu_hw_pingpong_ops : Interface to the pingpong Hw driver functions
> * Assumption is these functions will be called after clocks are enabled
> @@ -82,6 +104,12 @@ struct dpu_hw_pingpong_ops {
> * Obtain current vertical line counter
> */
> u32 (*get_line_count)(struct dpu_hw_pingpong *pp);
> +
> + /**
> + * Setup dither matix for pingpong block
> + */
> + void (*setup_dither)(struct dpu_hw_pingpong *pp,
> + struct dpu_hw_dither_cfg *cfg);
> };
>
> struct dpu_hw_pingpong {
> --
> 1.9.1
>