Re: [PATCH v8 04/19] drm/dsc: Add helpers for DSC picture parameter set infoframes

[Manasi Navare <manasi.d.navare@intel.com>]

On Mon, Nov 05, 2018 at 05:38:19PM -0800, Srivatsa, Anusha wrote:
> 
> 
> >-----Original Message-----
> >From: Navare, Manasi D
> >Sent: Friday, November 2, 2018 2:31 PM
> >To: intel-gfx@lists.freedesktop.org; dri-devel@lists.freedesktop.org
> >Cc: Navare, Manasi D <manasi.d.navare@intel.com>; Jani Nikula
> ><jani.nikula@linux.intel.com>; Ville Syrjala <ville.syrjala@linux.intel.com>;
> >Srivatsa, Anusha <anusha.srivatsa@intel.com>; Harry Wentland
> ><harry.wentland@amd.com>
> >Subject: [PATCH v8 04/19] drm/dsc: Add helpers for DSC picture parameter set
> >infoframes
> >
> >According to Display Stream compression spec 1.2, the picture parameter set
> >metadata is sent from source to sink device using the DP Secondary data packet.
> >An infoframe is formed for the PPS SDP header and PPS SDP payload bytes.
> >This patch adds helpers to fill the PPS SDP header and PPS SDP payload according
> >to the DSC 1.2 specification.
> >
> >v7:
> >* Use BUILD_BUG_ON() to protect changing struct size (Ville)
> >* Remove typecaseting (Ville)
> >* Include byteorder.h in drm_dsc.c (Ville)
> >v6:
> >* Use proper sequence points for breaking down the assignments (Chris Wilson)
> >* Use SPDX identifier
> >v5:
> >Do not use bitfields for DRM structs (Jani N)
> >v4:
> >* Use DSC constants for params that dont change across configurations
> >v3:
> >* Add reference to added kernel-docs in
> >Documentation/gpu/drm-kms-helpers.rst (Daniel Vetter)
> >
> >v2:
> >* Add EXPORT_SYMBOL for the drm functions (Manasi)
> >
> >Cc: dri-devel@lists.freedesktop.org
> >Cc: Jani Nikula <jani.nikula@linux.intel.com>
> >Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
> >Cc: Anusha Srivatsa <anusha.srivatsa@intel.com>
> >Cc: Harry Wentland <harry.wentland@amd.com>
> >Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
> >Acked-by: Harry Wentland <harry.wentland@amd.com>
> >---
> > Documentation/gpu/drm-kms-helpers.rst |  12 ++
> > drivers/gpu/drm/Makefile              |   2 +-
> > drivers/gpu/drm/drm_dsc.c             | 228 ++++++++++++++++++++++++++
> > include/drm/drm_dsc.h                 |  21 +++
> > 4 files changed, 262 insertions(+), 1 deletion(-)  create mode 100644
> >drivers/gpu/drm/drm_dsc.c
> >
> >diff --git a/Documentation/gpu/drm-kms-helpers.rst b/Documentation/gpu/drm-
> >kms-helpers.rst
> >index 4b4dc236ef6f..b422eb8edf16 100644
> >--- a/Documentation/gpu/drm-kms-helpers.rst
> >+++ b/Documentation/gpu/drm-kms-helpers.rst
> >@@ -232,6 +232,18 @@ MIPI DSI Helper Functions Reference  .. kernel-doc::
> >drivers/gpu/drm/drm_mipi_dsi.c
> >    :export:
> >
> >+Display Stream Compression Helper Functions Reference
> >+=====================================================
> >+
> >+.. kernel-doc:: drivers/gpu/drm/drm_dsc.c
> >+   :doc: dsc helpers
> >+
> >+.. kernel-doc:: include/drm/drm_dsc.h
> >+   :internal:
> >+
> >+.. kernel-doc:: drivers/gpu/drm/drm_dsc.c
> >+   :export:
> >+
> > Output Probing Helper Functions Reference
> >=========================================
> >
> >diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile index
> >576ba985e138..3a3e6fb6d476 100644
> >--- a/drivers/gpu/drm/Makefile
> >+++ b/drivers/gpu/drm/Makefile
> >@@ -32,7 +32,7 @@ drm-$(CONFIG_AGP) += drm_agpsupport.o
> > drm-$(CONFIG_DEBUG_FS) += drm_debugfs.o drm_debugfs_crc.o
> > drm-$(CONFIG_DRM_LOAD_EDID_FIRMWARE) += drm_edid_load.o
> >
> >-drm_kms_helper-y := drm_crtc_helper.o drm_dp_helper.o drm_probe_helper.o \
> >+drm_kms_helper-y := drm_crtc_helper.o drm_dp_helper.o drm_dsc.o
> >+drm_probe_helper.o \
> > 		drm_plane_helper.o drm_dp_mst_topology.o
> >drm_atomic_helper.o \
> > 		drm_kms_helper_common.o drm_dp_dual_mode_helper.o \
> > 		drm_simple_kms_helper.o drm_modeset_helper.o \ diff --git
> >a/drivers/gpu/drm/drm_dsc.c b/drivers/gpu/drm/drm_dsc.c new file mode
> >100644 index 000000000000..3a4942c1ae3b
> >--- /dev/null
> >+++ b/drivers/gpu/drm/drm_dsc.c
> >@@ -0,0 +1,228 @@
> >+// SPDX-License-Identifier: MIT
> 
> Nit-
> In some places the License is within /* */ like comment....
> Is the right way to Add License Identifier?

Yes /*  */ was giving me checkpatch warning.

> 
> >+/*
> >+ * Copyright © 2018 Intel Corp
> >+ *
> >+ * Author:
> >+ * Manasi Navare <manasi.d.navare@intel.com>  */
> >+
> >+#include <linux/kernel.h>
> >+#include <linux/module.h>
> >+#include <linux/init.h>
> >+#include <linux/errno.h>
> >+#include <linux/byteorder/generic.h>
> >+#include <drm/drm_dp_helper.h>
> >+#include <drm/drm_dsc.h>
> >+
> >+/**
> >+ * DOC: dsc helpers
> >+ *
> >+ * These functions contain some common logic and helpers to deal with
> >+VESA
> >+ * Display Stream Compression standard required for DSC on Display
> >+Port/eDP or
> >+ * MIPI display interfaces.
> >+ */
> >+
> >+/**
> >+ * drm_dsc_dp_pps_header_init() - Initializes the PPS Header
> >+ * for DisplayPort as per the DP 1.4 spec.
> >+ * @pps_sdp: Secondary data packet for DSC Picture Parameter Set  */
> >+void drm_dsc_dp_pps_header_init(struct drm_dsc_pps_infoframe *pps_sdp)
> >+{
> >+	memset(&pps_sdp->pps_header, 0, sizeof(pps_sdp->pps_header));
> >+
> >+	pps_sdp->pps_header.HB1 = DP_SDP_PPS;
> >+	pps_sdp->pps_header.HB2 =
> >DP_SDP_PPS_HEADER_PAYLOAD_BYTES_MINUS_1;
> >+}
> >+EXPORT_SYMBOL(drm_dsc_dp_pps_header_init);
> >+
> >+/**
> >+ * drm_dsc_pps_infoframe_pack() - Populates the DSC PPS infoframe
> >+ * using the DSC configuration parameters in the order expected
> >+ * by the DSC Display Sink device. For the DSC, the sink device
> >+ * expects the PPS payload in the big endian format for the fields
> >+ * that span more than 1 byte.
> >+ *
> >+ * @pps_sdp:
> >+ * Secondary data packet for DSC Picture Parameter Set
> >+ * @dsc_cfg:
> >+ * DSC Configuration data filled by driver  */ void
> >+drm_dsc_pps_infoframe_pack(struct drm_dsc_pps_infoframe *pps_sdp,
> >+				const struct drm_dsc_config *dsc_cfg) {
> >+	int i;
> >+
> >+	/*Protect against someone accidently changing struct size */
>            Nit -   ^^^ Missing space after /*

Cool will fix this missing space. Thanks for the review.

Manasi

> 
> Other than these nits, the patch looks good.
> 
> Reviewed-by: Anusha Srivatsa <anusha.srivatsa@intel.com?
> 
> >+	BUILD_BUG_ON(sizeof(pps_sdp->pps_payload) !=
> >+		     DP_SDP_PPS_HEADER_PAYLOAD_BYTES_MINUS_1 + 1);
> >+
> >+	memset(&pps_sdp->pps_payload, 0, sizeof(pps_sdp->pps_payload));
> >+
> >+	/* PPS 0 */
> >+	pps_sdp->pps_payload.dsc_version =
> >+		dsc_cfg->dsc_version_minor |
> >+		dsc_cfg->dsc_version_major <<
> >DSC_PPS_VERSION_MAJOR_SHIFT;
> >+
> >+	/* PPS 1, 2 is 0 */
> >+
> >+	/* PPS 3 */
> >+	pps_sdp->pps_payload.pps_3 =
> >+		dsc_cfg->line_buf_depth |
> >+		dsc_cfg->bits_per_component << DSC_PPS_BPC_SHIFT;
> >+
> >+	/* PPS 4 */
> >+	pps_sdp->pps_payload.pps_4 =
> >+		((dsc_cfg->bits_per_pixel & DSC_PPS_BPP_HIGH_MASK) >>
> >+		 DSC_PPS_MSB_SHIFT) |
> >+		dsc_cfg->vbr_enable << DSC_PPS_VBR_EN_SHIFT |
> >+		dsc_cfg->enable422 << DSC_PPS_SIMPLE422_SHIFT |
> >+		dsc_cfg->convert_rgb << DSC_PPS_CONVERT_RGB_SHIFT |
> >+		dsc_cfg->block_pred_enable <<
> >DSC_PPS_BLOCK_PRED_EN_SHIFT;
> >+
> >+	/* PPS 5 */
> >+	pps_sdp->pps_payload.bits_per_pixel_low =
> >+		(dsc_cfg->bits_per_pixel & DSC_PPS_LSB_MASK);
> >+
> >+	/*
> >+	 * The DSC panel expects the PPS packet to have big endian format
> >+	 * for data spanning 2 bytes. Use a macro cpu_to_be16() to convert
> >+	 * to big endian format. If format is little endian, it will swap
> >+	 * bytes to convert to Big endian else keep it unchanged.
> >+	 */
> >+
> >+	/* PPS 6, 7 */
> >+	pps_sdp->pps_payload.pic_height = cpu_to_be16(dsc_cfg->pic_height);
> >+
> >+	/* PPS 8, 9 */
> >+	pps_sdp->pps_payload.pic_width = cpu_to_be16(dsc_cfg->pic_width);
> >+
> >+	/* PPS 10, 11 */
> >+	pps_sdp->pps_payload.slice_height =
> >+cpu_to_be16(dsc_cfg->slice_height);
> >+
> >+	/* PPS 12, 13 */
> >+	pps_sdp->pps_payload.slice_width = cpu_to_be16(dsc_cfg->slice_width);
> >+
> >+	/* PPS 14, 15 */
> >+	pps_sdp->pps_payload.chunk_size =
> >+cpu_to_be16(dsc_cfg->slice_chunk_size);
> >+
> >+	/* PPS 16 */
> >+	pps_sdp->pps_payload.initial_xmit_delay_high =
> >+		((dsc_cfg->initial_xmit_delay &
> >+		  DSC_PPS_INIT_XMIT_DELAY_HIGH_MASK) >>
> >+		 DSC_PPS_MSB_SHIFT);
> >+
> >+	/* PPS 17 */
> >+	pps_sdp->pps_payload.initial_xmit_delay_low =
> >+		(dsc_cfg->initial_xmit_delay & DSC_PPS_LSB_MASK);
> >+
> >+	/* PPS 18, 19 */
> >+	pps_sdp->pps_payload.initial_dec_delay =
> >+		cpu_to_be16(dsc_cfg->initial_dec_delay);
> >+
> >+	/* PPS 20 is 0 */
> >+
> >+	/* PPS 21 */
> >+	pps_sdp->pps_payload.initial_scale_value =
> >+		dsc_cfg->initial_scale_value;
> >+
> >+	/* PPS 22, 23 */
> >+	pps_sdp->pps_payload.scale_increment_interval =
> >+		cpu_to_be16(dsc_cfg->scale_increment_interval);
> >+
> >+	/* PPS 24 */
> >+	pps_sdp->pps_payload.scale_decrement_interval_high =
> >+		((dsc_cfg->scale_decrement_interval &
> >+		  DSC_PPS_SCALE_DEC_INT_HIGH_MASK) >>
> >+		 DSC_PPS_MSB_SHIFT);
> >+
> >+	/* PPS 25 */
> >+	pps_sdp->pps_payload.scale_decrement_interval_low =
> >+		(dsc_cfg->scale_decrement_interval & DSC_PPS_LSB_MASK);
> >+
> >+	/* PPS 26[7:0], PPS 27[7:5] RESERVED */
> >+
> >+	/* PPS 27 */
> >+	pps_sdp->pps_payload.first_line_bpg_offset =
> >+		dsc_cfg->first_line_bpg_offset;
> >+
> >+	/* PPS 28, 29 */
> >+	pps_sdp->pps_payload.nfl_bpg_offset =
> >+		cpu_to_be16(dsc_cfg->nfl_bpg_offset);
> >+
> >+	/* PPS 30, 31 */
> >+	pps_sdp->pps_payload.slice_bpg_offset =
> >+		cpu_to_be16(dsc_cfg->slice_bpg_offset);
> >+
> >+	/* PPS 32, 33 */
> >+	pps_sdp->pps_payload.initial_offset =
> >+		cpu_to_be16(dsc_cfg->initial_offset);
> >+
> >+	/* PPS 34, 35 */
> >+	pps_sdp->pps_payload.final_offset =
> >+cpu_to_be16(dsc_cfg->final_offset);
> >+
> >+	/* PPS 36 */
> >+	pps_sdp->pps_payload.flatness_min_qp = dsc_cfg->flatness_min_qp;
> >+
> >+	/* PPS 37 */
> >+	pps_sdp->pps_payload.flatness_max_qp = dsc_cfg->flatness_max_qp;
> >+
> >+	/* PPS 38, 39 */
> >+	pps_sdp->pps_payload.rc_model_size =
> >+		cpu_to_be16(DSC_RC_MODEL_SIZE_CONST);
> >+
> >+	/* PPS 40 */
> >+	pps_sdp->pps_payload.rc_edge_factor =
> >DSC_RC_EDGE_FACTOR_CONST;
> >+
> >+	/* PPS 41 */
> >+	pps_sdp->pps_payload.rc_quant_incr_limit0 =
> >+		dsc_cfg->rc_quant_incr_limit0;
> >+
> >+	/* PPS 42 */
> >+	pps_sdp->pps_payload.rc_quant_incr_limit1 =
> >+		dsc_cfg->rc_quant_incr_limit1;
> >+
> >+	/* PPS 43 */
> >+	pps_sdp->pps_payload.rc_tgt_offset = DSC_RC_TGT_OFFSET_LO_CONST
> >|
> >+		DSC_RC_TGT_OFFSET_HI_CONST <<
> >DSC_PPS_RC_TGT_OFFSET_HI_SHIFT;
> >+
> >+	/* PPS 44 - 57 */
> >+	for (i = 0; i < DSC_NUM_BUF_RANGES - 1; i++)
> >+		pps_sdp->pps_payload.rc_buf_thresh[i] =
> >+			dsc_cfg->rc_buf_thresh[i];
> >+
> >+	/* PPS 58 - 87 */
> >+	/*
> >+	 * For DSC sink programming the RC Range parameter fields
> >+	 * are as follows: Min_qp[15:11], max_qp[10:6], offset[5:0]
> >+	 */
> >+	for (i = 0; i < DSC_NUM_BUF_RANGES; i++) {
> >+		pps_sdp->pps_payload.rc_range_parameters[i] =
> >+			((dsc_cfg->rc_range_params[i].range_min_qp <<
> >+			  DSC_PPS_RC_RANGE_MINQP_SHIFT) |
> >+			 (dsc_cfg->rc_range_params[i].range_max_qp <<
> >+			  DSC_PPS_RC_RANGE_MAXQP_SHIFT) |
> >+			 (dsc_cfg->rc_range_params[i].range_bpg_offset));
> >+		pps_sdp->pps_payload.rc_range_parameters[i] =
> >+			cpu_to_be16(pps_sdp-
> >>pps_payload.rc_range_parameters[i]);
> >+	}
> >+
> >+	/* PPS 88 */
> >+	pps_sdp->pps_payload.native_422_420 = dsc_cfg->native_422 |
> >+		dsc_cfg->native_420 << DSC_PPS_NATIVE_420_SHIFT;
> >+
> >+	/* PPS 89 */
> >+	pps_sdp->pps_payload.second_line_bpg_offset =
> >+		dsc_cfg->second_line_bpg_offset;
> >+
> >+	/* PPS 90, 91 */
> >+	pps_sdp->pps_payload.nsl_bpg_offset =
> >+		cpu_to_be16(dsc_cfg->nsl_bpg_offset);
> >+
> >+	/* PPS 92, 93 */
> >+	pps_sdp->pps_payload.second_line_offset_adj =
> >+		cpu_to_be16(dsc_cfg->second_line_offset_adj);
> >+
> >+	/* PPS 94 - 127 are O */
> >+}
> >+EXPORT_SYMBOL(drm_dsc_pps_infoframe_pack);
> >diff --git a/include/drm/drm_dsc.h b/include/drm/drm_dsc.h index
> >b88e31bd9da7..52e57ceaff80 100644
> >--- a/include/drm/drm_dsc.h
> >+++ b/include/drm/drm_dsc.h
> >@@ -24,6 +24,23 @@
> > #define DSC_RC_TGT_OFFSET_HI_CONST	    3
> > #define DSC_RC_TGT_OFFSET_LO_CONST	    3
> >
> >+/* DSC PPS constants and macros */
> >+#define DSC_PPS_VERSION_MAJOR_SHIFT		4
> >+#define DSC_PPS_BPC_SHIFT			4
> >+#define DSC_PPS_MSB_SHIFT			8
> >+#define DSC_PPS_LSB_MASK			(0xFF << 0)
> >+#define DSC_PPS_BPP_HIGH_MASK			(0x3 << 8)
> >+#define DSC_PPS_VBR_EN_SHIFT			2
> >+#define DSC_PPS_SIMPLE422_SHIFT			3
> >+#define DSC_PPS_CONVERT_RGB_SHIFT		4
> >+#define DSC_PPS_BLOCK_PRED_EN_SHIFT		5
> >+#define DSC_PPS_INIT_XMIT_DELAY_HIGH_MASK	(0x3 << 8)
> >+#define DSC_PPS_SCALE_DEC_INT_HIGH_MASK		(0xF << 8)
> >+#define DSC_PPS_RC_TGT_OFFSET_HI_SHIFT		4
> >+#define DSC_PPS_RC_RANGE_MINQP_SHIFT		11
> >+#define DSC_PPS_RC_RANGE_MAXQP_SHIFT		6
> >+#define DSC_PPS_NATIVE_420_SHIFT		1
> >+
> > /* Configuration for a single Rate Control model range */  struct
> >drm_dsc_rc_range_parameters {
> > 	/* Min Quantization Parameters allowed for this range */ @@ -458,4
> >+475,8 @@ struct drm_dsc_pps_infoframe {
> > 	struct drm_dsc_picture_parameter_set pps_payload;  } __packed;
> >
> >+void drm_dsc_dp_pps_header_init(struct drm_dsc_pps_infoframe *pps_sdp);
> >+void drm_dsc_pps_infoframe_pack(struct drm_dsc_pps_infoframe *pps_sdp,
> >+				const struct drm_dsc_config *dsc_cfg);
> >+
> > #endif /* _DRM_DSC_H_ */
> >--
> >2.18.0
> 
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