Re: [PATCH v5 15/19] drm/msm/dpu: initialize dpu encoder and connector for writeback

Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx> · Mon, 25 Apr 2022 17:42:25 -0700

Hi Laurent

On 4/25/2022 5:32 PM, Laurent Pinchart wrote:
Hi Abhinav,

On Sun, Apr 24, 2022 at 05:32:06PM -0700, Abhinav Kumar wrote:
Initialize dpu encoder and connector for writeback if the
target supports it in the catalog.

changes in v2:
	- start initialing the encoder for writeback since we
	have migrated to using drm_writeback_connector_init_with_encoder()
	- instead of checking for WB_2 inside _dpu_kms_initialize_writeback
	call it only when its WB_2
	- rebase on tip of msm-next and remove usage of priv->encoders

changes in v3:
	- none

changes in v4:
	- fix copyright years order

Signed-off-by: Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
---
  drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 27 +++++++++----
  drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c     | 61 ++++++++++++++++++++++++++++-
  2 files changed, 80 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
index 24870eb..2d79002 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
@@ -2102,7 +2102,7 @@ static void dpu_encoder_early_unregister(struct drm_encoder *encoder)
  }
  
  static int dpu_encoder_virt_add_phys_encs(
-		u32 display_caps,
+		struct msm_display_info *disp_info,
  		struct dpu_encoder_virt *dpu_enc,
  		struct dpu_enc_phys_init_params *params)
  {
@@ -2121,7 +2121,7 @@ static int dpu_encoder_virt_add_phys_encs(
  		return -EINVAL;
  	}
  
-	if (display_caps & MSM_DISPLAY_CAP_VID_MODE) {
+	if (disp_info->capabilities & MSM_DISPLAY_CAP_VID_MODE) {
  		enc = dpu_encoder_phys_vid_init(params);
  
  		if (IS_ERR_OR_NULL(enc)) {
@@ -2134,7 +2134,7 @@ static int dpu_encoder_virt_add_phys_encs(
  		++dpu_enc->num_phys_encs;
  	}
  
-	if (display_caps & MSM_DISPLAY_CAP_CMD_MODE) {
+	if (disp_info->capabilities & MSM_DISPLAY_CAP_CMD_MODE) {
  		enc = dpu_encoder_phys_cmd_init(params);
  
  		if (IS_ERR_OR_NULL(enc)) {
@@ -2147,6 +2147,19 @@ static int dpu_encoder_virt_add_phys_encs(
  		++dpu_enc->num_phys_encs;
  	}
  
+	if (disp_info->intf_type == DRM_MODE_ENCODER_VIRTUAL) {
+		enc = dpu_encoder_phys_wb_init(params);
+
+		if (IS_ERR_OR_NULL(enc)) {
+			DPU_ERROR_ENC(dpu_enc, "failed to init wb enc: %ld\n",
+					PTR_ERR(enc));
+			return enc == NULL ? -EINVAL : PTR_ERR(enc);
+		}
+
+		dpu_enc->phys_encs[dpu_enc->num_phys_encs] = enc;
+		++dpu_enc->num_phys_encs;
+	}
+
  	if (params->split_role == ENC_ROLE_SLAVE)
  		dpu_enc->cur_slave = enc;
  	else
@@ -2248,9 +2261,8 @@ static int dpu_encoder_setup_display(struct dpu_encoder_virt *dpu_enc,
  		}
  
  		if (!ret) {
-			ret = dpu_encoder_virt_add_phys_encs(disp_info->capabilities,
-												 dpu_enc,
-												 &phys_params);
+			ret = dpu_encoder_virt_add_phys_encs(disp_info,
+					dpu_enc, &phys_params);
  			if (ret)
  				DPU_ERROR_ENC(dpu_enc, "failed to add phys encs\n");
  		}
@@ -2367,8 +2379,9 @@ struct drm_encoder *dpu_encoder_init(struct drm_device *dev,
  	if (!dpu_enc)
  		return ERR_PTR(-ENOMEM);
  
+
  	rc = drm_encoder_init(dev, &dpu_enc->base, &dpu_encoder_funcs,
-			drm_enc_mode, NULL);
+							  drm_enc_mode, NULL);
  	if (rc) {
  		devm_kfree(dev->dev, dpu_enc);
  		return ERR_PTR(rc);
diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
index c683cab..9a406e1 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
@@ -1,7 +1,9 @@
  // SPDX-License-Identifier: GPL-2.0-only
  /*
- * Copyright (c) 2014-2018, The Linux Foundation. All rights reserved.
   * Copyright (C) 2013 Red Hat
+ * Copyright (c) 2014-2018, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.
+ *
   * Author: Rob Clark <robdclark@xxxxxxxxx>
   */
  
@@ -15,6 +17,7 @@
  #include <drm/drm_crtc.h>
  #include <drm/drm_file.h>
  #include <drm/drm_vblank.h>
+#include <drm/drm_writeback.h>
  
  #include "msm_drv.h"
  #include "msm_mmu.h"
@@ -29,6 +32,7 @@
  #include "dpu_kms.h"
  #include "dpu_plane.h"
  #include "dpu_vbif.h"
+#include "dpu_writeback.h"
  
  #define CREATE_TRACE_POINTS
  #include "dpu_trace.h"
@@ -648,6 +652,45 @@ static int _dpu_kms_initialize_displayport(struct drm_device *dev,
  	return 0;
  }
  
+static int _dpu_kms_initialize_writeback(struct drm_device *dev,
+		struct msm_drm_private *priv, struct dpu_kms *dpu_kms,
+		const u32 *wb_formats, int n_formats)
+{
+	struct drm_encoder *encoder = NULL;
+	struct msm_display_info info;
+	int rc;
+
+	encoder = dpu_encoder_init(dev, DRM_MODE_ENCODER_VIRTUAL);

I'm puzzled. I thought the whole purpose of the
drm_writeback_connector_init_with_encoder() function was to share an
encoder between writeback and a real display output, but the encoder you
create here seems to be specific to writeback. What am I missing ?

There are two purposes as I had written:


"For vendors drivers which pass an already allocated and
initialized encoder especially for cases where the encoder
hardware is shared OR the writeback encoder shares the resources
with the rest of the display pipeline introduce a new API"

1) To share the display hardware such as clocks/interrupts between our 
display hardware

And yes, if you observe, our DPU writeback encoder shares the hardware 
functionality for those pieces in dpu_encoder. So it is a real encoder.

2) To share an encoder between writeback and real display output.

This series will be slowly extended to support that encoder as well.

This is the first series which adds basic writeback support to our 
driver only for one DPU chipset sm8250.

https://patchwork.freedesktop.org/patch/483218/?series=99724&rev=5

Our hardware also supports the functionality of sharing the encoder 
between writeback and real display output.

I will add that on top of this.

In older chipsets also, where the encoder will be shared will again have 
to supported on top of this series.

So this is just the first series to add support, we will keep building 
on top of this to add support for multiple chipsets which will cover all 
the cases I explained why we need this.

Thanks

Abhinav

+	if (IS_ERR(encoder)) {
+		DPU_ERROR("encoder init failed for dsi display\n");
+		return PTR_ERR(encoder);
+	}
+
+	memset(&info, 0, sizeof(info));
+
+	rc = dpu_writeback_init(dev, encoder, wb_formats,
+			n_formats);
+	if (rc) {
+		DPU_ERROR("dpu_writeback_init, rc = %d\n", rc);
+		drm_encoder_cleanup(encoder);
+		return rc;
+	}
+
+	info.num_of_h_tiles = 1;
+	/* use only WB idx 2 instance for DPU */
+	info.h_tile_instance[0] = WB_2;
+	info.intf_type = encoder->encoder_type;
+
+	rc = dpu_encoder_setup(dev, encoder, &info);
+	if (rc) {
+		DPU_ERROR("failed to setup DPU encoder %d: rc:%d\n",
+				  encoder->base.id, rc);
+		return rc;
+	}
+
+	return 0;
+}
+
  /**
   * _dpu_kms_setup_displays - create encoders, bridges and connectors
   *                           for underlying displays
@@ -661,6 +704,7 @@ static int _dpu_kms_setup_displays(struct drm_device *dev,
  				    struct dpu_kms *dpu_kms)
  {
  	int rc = 0;
+	int i;
  
  	rc = _dpu_kms_initialize_dsi(dev, priv, dpu_kms);
  	if (rc) {
@@ -674,6 +718,21 @@ static int _dpu_kms_setup_displays(struct drm_device *dev,
  		return rc;
  	}
  
+	/* Since WB isn't a driver check the catalog before initializing */
+	if (dpu_kms->catalog->wb_count) {
+		for (i = 0; i < dpu_kms->catalog->wb_count; i++) {
+			if (dpu_kms->catalog->wb[i].id == WB_2) {
+				rc = _dpu_kms_initialize_writeback(dev, priv, dpu_kms,
+						dpu_kms->catalog->wb[i].format_list,
+						dpu_kms->catalog->wb[i].num_formats);
+				if (rc) {
+					DPU_ERROR("initialize_WB failed, rc = %d\n", rc);
+					return rc;
+				}
+			}
+		}
+	}
+
  	return rc;
  }
  







