Re: [PATCH v3 2/3] drm/msm/dpu: use dpu core's major version to enable data compress

From: Dmitry Baryshkov
Date: Thu Jun 29 2023 - 23:23:05 EST


On 30/06/2023 06:07, Abhinav Kumar wrote:


On 6/29/2023 5:20 PM, Dmitry Baryshkov wrote:
On 29/06/2023 22:29, Abhinav Kumar wrote:
Instead of using a feature bit to decide whether to enable data
compress or not for DSC use-cases, use dpu core's major version instead.
This will avoid defining feature bits for every bit level details of
registers.

Also, rename the intf's enable_compression() op to program_datapath()
and allow it to accept a struct intf_dpu_datapath_cfg to program
all the bits at once. This can be re-used by widebus later on as
well as it touches the same register.

Two separate commits please, because...


I thought of it but it seemed better together and was the only way I could think of. Please see below.

Signed-off-by: Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx>
---
  .../gpu/drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c |  9 +++++++--
  drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.c      |  9 +++++----
  drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.h      | 16 ++++++++++++++--
  3 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c
index b856c6286c85..f4e15b4c4cc9 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c
@@ -50,6 +50,7 @@ static void _dpu_encoder_phys_cmd_update_intf_cfg(
              to_dpu_encoder_phys_cmd(phys_enc);
      struct dpu_hw_ctl *ctl;
      struct dpu_hw_intf_cfg intf_cfg = { 0 };
+    struct dpu_kms *dpu_kms = phys_enc->dpu_kms;
      ctl = phys_enc->hw_ctl;
      if (!ctl->ops.setup_intf_cfg)
@@ -68,8 +69,12 @@ static void _dpu_encoder_phys_cmd_update_intf_cfg(
                  phys_enc->hw_intf,
                  phys_enc->hw_pp->idx);
-    if (intf_cfg.dsc != 0 && phys_enc->hw_intf->ops.enable_compression)
-        phys_enc->hw_intf->ops.enable_compression(phys_enc->hw_intf);
+    if (intf_cfg.dsc != 0 && dpu_kms->catalog->core_major_version >= 0x7) {

... because this becomes incorrect. The datapath should be programmed in all the cases, if there is a corresponding callback. intf_cfg.dsc should be used as a condition to set datapath_cfg.


The issue is that today we do not have dpu_mdss_cfg as part of dpu_hw_intf nor _setup_intf_ops because all of those have been dropped with some rework or cleanup.

Pass dpu_mdss_cfg to dpu_hw_intf_init(). It was removed as a cleanup, now we can reintroduce it.


Ideally even I would like to assign this op only for core_rev >=7 but that information is no longer available. We would have to start passing the major and minor versions to _setup_intf_ops() to go with that approach. So without making all of those changes, the only way I had was to assign the op unconditionally but call it only for major_rev >= 7.

Passing core_rev to the op itself so that we can write the register only for core_rev >=7 is an option but then what if some bits start becoming usable only after minor rev. then we will have to start passing major and minor rev to program_datapath too. Again getting little messy.

I am open to ideas to achieve the goal of assigning this op only for core_rev >=7 other than what I wrote above.


+        struct intf_dpu_datapath_cfg datapath_cfg = { 0 };

No need for `0' in the init, empty braces would be enough.


ack.

+
+        datapath_cfg.data_compress = true;
+        phys_enc->hw_intf->ops.program_datapath(phys_enc->hw_intf, &datapath_cfg);
+    }
  }
  static void dpu_encoder_phys_cmd_pp_tx_done_irq(void *arg, int irq_idx)
diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.c
index 5b0f6627e29b..85333df08fbc 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.c
@@ -513,11 +513,13 @@ static void dpu_hw_intf_disable_autorefresh(struct dpu_hw_intf *intf,
  }
-static void dpu_hw_intf_enable_compression(struct dpu_hw_intf *ctx)
+static void dpu_hw_intf_program_datapath(struct dpu_hw_intf *ctx,
+                     struct intf_dpu_datapath_cfg *datapath_cfg)
  {
      u32 intf_cfg2 = DPU_REG_READ(&ctx->hw, INTF_CONFIG2);
-    intf_cfg2 |= INTF_CFG2_DCE_DATA_COMPRESS;
+    if (datapath_cfg->data_compress)
+        intf_cfg2 |= INTF_CFG2_DCE_DATA_COMPRESS;
      DPU_REG_WRITE(&ctx->hw, INTF_CONFIG2, intf_cfg2);
  }
@@ -543,8 +545,7 @@ static void _setup_intf_ops(struct dpu_hw_intf_ops *ops,
          ops->disable_autorefresh = dpu_hw_intf_disable_autorefresh;
      }
-    if (cap & BIT(DPU_INTF_DATA_COMPRESS))
-        ops->enable_compression = dpu_hw_intf_enable_compression;
+    ops->program_datapath = dpu_hw_intf_program_datapath;

The `core_major_version >= 7' should either be here or in the callback itself.


Yes, ideally I would like it like that but please see above why I couldnt do it.

  }
  struct dpu_hw_intf *dpu_hw_intf_init(const struct dpu_intf_cfg *cfg,
diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.h b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.h
index 99e21c4137f9..f736dca38463 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.h
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.h
@@ -48,6 +48,11 @@ struct intf_status {
      u32 line_count;        /* current line count including blanking */
  };
+struct intf_dpu_datapath_cfg {
+    u8 data_compress;    /* enable data compress between dpu and dsi */
+    /* can be expanded for other programmable bits */
+};

I'd say, dpu_datapath is too generic. What about  intf_cmd_mode_cfg?


The goal was to keep it generic. Its actually the handshake between DPU and interface datapath so I chose that name.

Do you have plans of using it for the video mode?


This is not specific to command mode and intf_cfg is already there so I chose that one :)

+
  /**
   * struct dpu_hw_intf_ops : Interface to the interface Hw driver functions
   *  Assumption is these functions will be called after clocks are enabled
@@ -70,7 +75,7 @@ struct intf_status {
   * @get_autorefresh:            Retrieve autorefresh config from hardware
   *                              Return: 0 on success, -ETIMEDOUT on timeout
   * @vsync_sel:                  Select vsync signal for tear-effect configuration
- * @enable_compression:         Enable data compression
+ * @program_datapath:           Program the DPU to interface datapath for relevant chipsets
   */
  struct dpu_hw_intf_ops {
      void (*setup_timing_gen)(struct dpu_hw_intf *intf,
@@ -108,7 +113,14 @@ struct dpu_hw_intf_ops {
       */
      void (*disable_autorefresh)(struct dpu_hw_intf *intf, uint32_t encoder_id, u16 vdisplay);
-    void (*enable_compression)(struct dpu_hw_intf *intf);
+    /**
+     * Program the DPU to intf datapath by specifying
+     * which of the settings need to be programmed for
+     * use-cases which need DPU-intf handshake such as
+     * widebus, compression etc.

This is not a valid kerneldoc.


hmmm ... ok so just // ?

I referred disable_autorefresh from above and did the same.

+     */
+    void (*program_datapath)(struct dpu_hw_intf *intf,
+                 struct intf_dpu_datapath_cfg *datapath_cfg);
  };
  struct dpu_hw_intf {


--
With best wishes
Dmitry