RE: [v6] drm/msm/disp/dpu1: add support for dspp sub block flush in sc7280

[Kalyan Thota]

>-----Original Message-----
>From: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
>Sent: Tuesday, October 4, 2022 8:03 PM
>To: Kalyan Thota (QUIC) <quic_kalyant@xxxxxxxxxxx>
>Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx; linux-arm-msm@xxxxxxxxxxxxxxx;
>freedreno@xxxxxxxxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; linux-
>kernel@xxxxxxxxxxxxxxx; robdclark@xxxxxxxxx; dianders@xxxxxxxxxxxx;
>swboyd@xxxxxxxxxxxx; Vinod Polimera (QUIC) <quic_vpolimer@xxxxxxxxxxx>;
>Abhinav Kumar (QUIC) <quic_abhinavk@xxxxxxxxxxx>
>Subject: Re: [v6] drm/msm/disp/dpu1: add support for dspp sub block flush in
>sc7280
>
>WARNING: This email originated from outside of Qualcomm. Please be wary of
>any links or attachments, and do not enable macros.
>
>On Sun, 2 Oct 2022 at 06:15, Kalyan Thota <quic_kalyant@xxxxxxxxxxx> wrote:
>>
>> Flush mechanism for DSPP blocks has changed in sc7280 family, it
>> allows individual sub blocks to be flushed in coordination with master
>> flush control.
>>
>> Representation: master_flush && (PCC_flush | IGC_flush .. etc )
>>
>> This change adds necessary support for the above design.
>>
>> Changes in v1:
>> - Few nits (Doug, Dmitry)
>> - Restrict sub-block flush programming to dpu_hw_ctl file (Dmitry)
>>
>> Changes in v2:
>> - Move the address offset to flush macro (Dmitry)
>> - Seperate ops for the sub block flush (Dmitry)
>>
>> Changes in v3:
>> - Reuse the DPU_DSPP_xx enum instead of a new one (Dmitry)
>>
>> Changes in v4:
>> - Use shorter version for unsigned int (Stephen)
>>
>> Changes in v5:
>> - Spurious patch please ignore.
>>
>> Changes in v6:
>> - Add SOB tag (Doug, Dmitry)
>>
>> Signed-off-by: Kalyan Thota <quic_kalyant@xxxxxxxxxxx>
>> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
>> ---
>>  drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c       |  2 +-
>>  drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.c |  5 +++-
>> drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h |  4 +++
>>  drivers/gpu/drm/msm/disp/dpu1/dpu_hw_ctl.c     | 35
>++++++++++++++++++++++++--
>>  drivers/gpu/drm/msm/disp/dpu1/dpu_hw_ctl.h     | 10 ++++++--
>>  5 files changed, 50 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
>> b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
>> index 601d687..4170fbe 100644
>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
>> @@ -766,7 +766,7 @@ static void _dpu_crtc_setup_cp_blocks(struct
>> drm_crtc *crtc)
>>
>>                 /* stage config flush mask */
>>                 ctl->ops.update_pending_flush_dspp(ctl,
>> -                       mixer[i].hw_dspp->idx);
>> +                       mixer[i].hw_dspp->idx, DPU_DSPP_PCC);
>>         }
>>  }
>>
>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.c
>> b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.c
>> index 27f029f..0eecb2f 100644
>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.c
>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.c
>> @@ -65,7 +65,10 @@
>>         (PINGPONG_SDM845_MASK | BIT(DPU_PINGPONG_TE2))
>>
>>  #define CTL_SC7280_MASK \
>> -       (BIT(DPU_CTL_ACTIVE_CFG) | BIT(DPU_CTL_FETCH_ACTIVE) |
>BIT(DPU_CTL_VM_CFG))
>> +       (BIT(DPU_CTL_ACTIVE_CFG) | \
>> +        BIT(DPU_CTL_FETCH_ACTIVE) | \
>> +        BIT(DPU_CTL_VM_CFG) | \
>> +        BIT(DPU_CTL_DSPP_SUB_BLOCK_FLUSH))
>>
>>  #define MERGE_3D_SM8150_MASK (0)
>>
>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h
>> b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h
>> index 38aa38a..8148e91 100644
>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h
>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h
>> @@ -161,10 +161,12 @@ enum {
>>   * DSPP sub-blocks
>>   * @DPU_DSPP_PCC             Panel color correction block
>>   * @DPU_DSPP_GC              Gamma correction block
>> + * @DPU_DSPP_IGC             Inverse Gamma correction block
>>   */
>>  enum {
>>         DPU_DSPP_PCC = 0x1,
>>         DPU_DSPP_GC,
>> +       DPU_DSPP_IGC,
>>         DPU_DSPP_MAX
>>  };
>>
>> @@ -191,6 +193,7 @@ enum {
>>   * @DPU_CTL_SPLIT_DISPLAY:     CTL supports video mode split display
>>   * @DPU_CTL_FETCH_ACTIVE:      Active CTL for fetch HW (SSPPs)
>>   * @DPU_CTL_VM_CFG:            CTL config to support multiple VMs
>> + * @DPU_CTL_DSPP_BLOCK_FLUSH: CTL config to support dspp sub-block
>> + flush
>>   * @DPU_CTL_MAX
>>   */
>>  enum {
>> @@ -198,6 +201,7 @@ enum {
>>         DPU_CTL_ACTIVE_CFG,
>>         DPU_CTL_FETCH_ACTIVE,
>>         DPU_CTL_VM_CFG,
>> +       DPU_CTL_DSPP_SUB_BLOCK_FLUSH,
>>         DPU_CTL_MAX
>>  };
>>
>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_ctl.c
>> b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_ctl.c
>> index a35ecb6..f26f484 100644
>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_ctl.c
>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_ctl.c
>> @@ -33,6 +33,7 @@
>>  #define   CTL_INTF_FLUSH                0x110
>>  #define   CTL_INTF_MASTER               0x134
>>  #define   CTL_FETCH_PIPE_ACTIVE         0x0FC
>> +#define   CTL_DSPP_n_FLUSH(n)          ((0x13C) + ((n - 1) * 4))
>>
>>  #define CTL_MIXER_BORDER_OUT            BIT(24)
>>  #define CTL_FLUSH_MASK_CTL              BIT(17)
>> @@ -287,8 +288,9 @@ static void
>> dpu_hw_ctl_update_pending_flush_merge_3d_v1(struct dpu_hw_ctl *ctx,  }
>>
>>  static void dpu_hw_ctl_update_pending_flush_dspp(struct dpu_hw_ctl *ctx,
>> -       enum dpu_dspp dspp)
>> +       enum dpu_dspp dspp, u32 dspp_sub_blk)
>>  {
>> +
>>         switch (dspp) {
>>         case DSPP_0:
>>                 ctx->pending_flush_mask |= BIT(13); @@ -307,6 +309,31
>> @@ static void dpu_hw_ctl_update_pending_flush_dspp(struct dpu_hw_ctl
>*ctx,
>>         }
>>  }
>>
>> +static void dpu_hw_ctl_update_pending_flush_dspp_subblocks(
>> +       struct dpu_hw_ctl *ctx, enum dpu_dspp dspp, u32 dspp_sub_blk)
>> +{
>> +       u32 flushbits = 0, active;
>> +
>> +       switch (dspp_sub_blk) {
>> +       case DPU_DSPP_IGC:
>> +               flushbits = BIT(2);
>> +               break;
>> +       case DPU_DSPP_PCC:
>> +               flushbits = BIT(4);
>> +               break;
>> +       case DPU_DSPP_GC:
>> +               flushbits = BIT(5);
>> +               break;
>> +       default:
>> +               return;
>> +       }
>> +
>> +       active = DPU_REG_READ(&ctx->hw, CTL_DSPP_n_FLUSH(dspp));
>> +       DPU_REG_WRITE(&ctx->hw, CTL_DSPP_n_FLUSH(dspp), active |
>> + flushbits);
>> +
>> +       ctx->pending_flush_mask |= BIT(29); }
>> +
>>  static u32 dpu_hw_ctl_poll_reset_status(struct dpu_hw_ctl *ctx, u32
>> timeout_us)  {
>>         struct dpu_hw_blk_reg_map *c = &ctx->hw; @@ -675,7 +702,11 @@
>> static void _setup_ctl_ops(struct dpu_hw_ctl_ops *ops,
>>         ops->setup_blendstage = dpu_hw_ctl_setup_blendstage;
>>         ops->update_pending_flush_sspp =
>dpu_hw_ctl_update_pending_flush_sspp;
>>         ops->update_pending_flush_mixer =
>dpu_hw_ctl_update_pending_flush_mixer;
>> -       ops->update_pending_flush_dspp =
>dpu_hw_ctl_update_pending_flush_dspp;
>> +       if (cap & BIT(DPU_CTL_DSPP_SUB_BLOCK_FLUSH))
>> +               ops->update_pending_flush_dspp =
>dpu_hw_ctl_update_pending_flush_dspp_subblocks;
>> +       else
>> +               ops->update_pending_flush_dspp =
>> + dpu_hw_ctl_update_pending_flush_dspp;
>> +
>>         if (cap & BIT(DPU_CTL_FETCH_ACTIVE))
>>                 ops->set_active_pipes =
>> dpu_hw_ctl_set_fetch_pipe_active;  }; diff --git
>> a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_ctl.h
>> b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_ctl.h
>> index 96c012e..1743572 100644
>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_ctl.h
>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_ctl.h
>> @@ -149,12 +149,18 @@ struct dpu_hw_ctl_ops {
>>
>>         /**
>>          * OR in the given flushbits to the cached pending_flush_mask
>> -        * No effect on hardware
>> +        *
>> +        * If the hardware supports dspp sub block flush, then sub-block
>> +        * flushes are written to the hardware and main dspp flush will
>> +        * be cached in the pending_flush_mask.
>
>Ok, this changes the semantic of the update_pending_FOO_mask.
>Can we cache the pending DSPP blocks instead and flush them together with the
>rest of pending flushes?
>
Sure, I thought about it during initial implementation, the only reason to pull back was that caching the 
values will bring in additional overhead of clearing them, whereas HW will self-clear the bits after they
are consumed removing the overhead. Main flush which includes master dspp flush bit is however cleared in the current implementation.

Let me know if you think dspp flush caching is better, I'll push a patch for it.

>> +        *
>>          * @ctx       : ctl path ctx pointer
>>          * @blk       : DSPP block index
>> +        * @dspp_sub_blk : DSPP sub-block index
>>          */
>>         void (*update_pending_flush_dspp)(struct dpu_hw_ctl *ctx,
>> -               enum dpu_dspp blk);
>> +               enum dpu_dspp blk,  u32 dspp_sub_blk);
>> +
>>         /**
>>          * Write the value of the pending_flush_mask to hardware
>>          * @ctx       : ctl path ctx pointer
>> --
>> 2.7.4
>>
>
>
>--
>With best wishes
>Dmitry