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Date:   Thu, 25 Jun 2020 12:58:11 +0530
From:   kalyan_t@codeaurora.org
To:     Rob Clark <robdclark@gmail.com>
Cc:     "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>,
        Krishna Manikandan <mkrishn@codeaurora.org>,
        linux-arm-msm <linux-arm-msm@vger.kernel.org>,
        Raviteja Tamatam <travitej@codeaurora.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        Douglas Anderson <dianders@chromium.org>,
        nganji@codeaurora.org, Sean Paul <seanpaul@chromium.org>,
        "Kristian H. Kristensen" <hoegsberg@chromium.org>,
        freedreno <freedreno@lists.freedesktop.org>
Subject: Re: [Freedreno] [PATCH] drm/msm/dpu: add support for dither block in
 display
In-Reply-To: <CAF6AEGs_E+8p=-o1BHkAbAa8qY1ZaU8rPJsfzqV5L4wBBhvcAg@mail.gmail.com>
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 <CAF6AEGs_E+8p=-o1BHkAbAa8qY1ZaU8rPJsfzqV5L4wBBhvcAg@mail.gmail.com>
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On 2020-06-25 01:55, Rob Clark wrote:
> On Wed, Jun 24, 2020 at 4:57 AM Kalyan Thota <kalyan_t@codeaurora.org> 
> 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@codeaurora.org>
>> ---
>>  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
> 
Sure, will fix them. I guess got habituated to add checks so that static 
code analyzers don't complain :-)

Kalyan

>> +
>> +       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
>> 
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