Re: [PATCH v6 08/28] drm/dsc: Define Display Stream Compression PPS infoframe

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

On Thu, Nov 01, 2018 at 06:42:17PM +0200, Ville Syrjälä wrote:
> On Wed, Oct 24, 2018 at 03:28:20PM -0700, Manasi Navare wrote:
> > This patch defines a new header file for all the DSC 1.2 structures
> > and creates a structure for PPS infoframe which will be used to send
> > picture parameter set secondary data packet for display stream compression.
> > All the PPS infoframe syntax elements are taken from DSC 1.2 specification
> > from VESA.
> > 
> > v3:
> > * Add the SPDX shorthand (Chris Wilson)
> > v2:
> > * Do not use bitfields in the struct (Jani Nikula)
> > 
> > Cc: Gaurav K Singh <gaurav.k.singh@intel.com>
> > 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>
> > Reviewed-by: Harry Wentland <harry.wentland@amd.com>
> > ---
> >  include/drm/drm_dsc.h | 347 ++++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 347 insertions(+)
> >  create mode 100644 include/drm/drm_dsc.h
> > 
> > diff --git a/include/drm/drm_dsc.h b/include/drm/drm_dsc.h
> > new file mode 100644
> > index 000000000000..1d8a03983b90
> > --- /dev/null
> > +++ b/include/drm/drm_dsc.h
> > @@ -0,0 +1,347 @@
> > +/* SPDX-License-Identifier: MIT
> > + * Copyright (C) 2018 Intel Corp.
> > + *
> > + * Authors:
> > + * Manasi Navare <manasi.d.navare@intel.com>
> > + */
> > +
> > +#ifndef DRM_DSC_H_
> > +#define DRM_DSC_H_
> > +
> > +#include <drm/drm_dp_helper.h>
> > +
> > +/* VESA Display Stream Compression DSC 1.2 constants */
> > +#define DSC_NUM_BUF_RANGES	15
> 
> DRM_DSC_...  perhasp?
> 
> > +
> > +/**
> > + * struct picture_parameter_set - Represents 128 bytes of Picture Parameter Set
> > + *
> > + * The VESA DSC standard defines picture parameter set (PPS) which display
> > + * stream compression encoders must communicate to decoders.
> > + * The PPS is encapsulated in 128 bytes (PPS 0 through PPS 127). The fields in
> > + * this structure are as per Table 4.1 in Vesa DSC specification v1.1/v1.2.
> > + * The PPS fields that span over more than a byte should be stored in Big Endian
> > + * format.
> > + */
> > +struct picture_parameter_set {
> 
> Needs a namespace too. Probably best make this struct packed. A
> BUILD_BUG_ON() somewhere to verify the size might also be nice.
>

By namespace you mean renaming this struct as dsc_picture_parameter_set?
And yes will make this struct packed.
BUILD_BUG_ON() before using it to make sure the size is still 128 bytes?

 
> > +	/**
> > +	 * @dsc_version:
> > +	 * PPS0[3:0] - dsc_version_minor: Contains Minor version of DSC
> > +	 * PPS0[7:4] - dsc_version_major: Contains major version of DSC
> > +	 */
> > +	u8 dsc_version;
> > +	/**
> > +	 * @pps_identifier:
> > +	 * PPS1[7:0] - Application specific identifier that can be
> > +	 * used to differentiate between different PPS tables.
> > +	 */
> > +	u8 pps_identifier;
> > +	/**
> > +	 * @pps_reserved:
> > +	 * PPS2[7:0]- RESERVED Byte
> > +	 */
> > +	u8 pps_reserved;
> > +	/**
> > +	 * @pps_3:
> > +	 * PPS3[3:0] - linebuf_depth: Contains linebuffer bit depth used to
> > +	 * generate the bitstream. (0x0 - 16 bits for DSC 1.2, 0x8 - 8 bits,
> > +	 * 0xA - 10 bits, 0xB - 11 bits, 0xC - 12 bits, 0xD - 13 bits,
> > +	 * 0xE - 14 bits for DSC1.2, 0xF - 14 bits for DSC 1.2.
> > +	 * PPS3[7:4] - bits_per_component: Bits per component for the original
> > +	 * pixels of the encoded picture.
> > +	 * 0x0 = 16bpc (allowed only when dsc_version_minor = 0x2)
> > +	 * 0x8 = 8bpc, 0xA = 10bpc, 0xC = 12bpc, 0xE = 14bpc (also
> > +	 * allowed only when dsc_minor_version = 0x2)
> > +	 */
> > +	u8 pps_3;
> > +	/**
> > +	 * @pps_4:
> > +	 * PPS4[1:0] -These are the most significant 2 bits of
> > +	 * compressed BPP bits_per_pixel[9:0] syntax element.
> > +	 * PPS4[2] - vbr_enable: 0 = VBR disabled, 1 = VBR enabled
> > +	 * PPS4[3] - simple_422: Indicates if decoder drops samples to
> > +	 * reconstruct the 4:2:2 picture.
> > +	 * PPS4[4] - Convert_rgb: Indicates if DSC color space conversion is
> > +	 * active.
> > +	 * PPS4[5] - blobk_pred_enable: Indicates if BP is used to code any
> > +	 * groups in picture
> > +	 * PPS4[7:6] - Reseved bits
> > +	 */
> > +	u8 pps_4;
> > +	/**
> > +	 * @bits_per_pixel_low:
> > +	 * PPS5[7:0] - This indicates the lower significant 8 bits of
> > +	 * the compressed BPP bits_per_pixel[9:0] element.
> > +	 */
> > +	u8 bits_per_pixel_low;
> > +	/**
> > +	 * @pic_height:
> > +	 * PPS6[7:0], PPS7[7:0] -pic_height: Specifies the number of pixel rows
> > +	 * within the raster.
> > +	 */
> > +	__be16 pic_height;
> > +	/**
> > +	 * @pic_width:
> > +	 * PPS8[7:0], PPS9[7:0] - pic_width: Number of pixel columns within
> > +	 * the raster.
> > +	 */
> > +	__be16 pic_width;
> > +	/**
> > +	 * @slice_height:
> > +	 * PPS10[7:0], PPS11[7:0] - Slice height in units of pixels.
> > +	 */
> > +	__be16 slice_height;
> > +	/**
> > +	 * @slice_width:
> > +	 * PPS12[7:0], PPS13[7:0] - Slice width in terms of pixels.
> > +	 */
> > +	__be16 slice_width;
> > +	/**
> > +	 * @chunk_size:
> > +	 * PPS14[7:0], PPS15[7:0] - Size in units of bytes of the chunks
> > +	 * that are used for slice multiplexing.
> > +	 */
> > +	__be16 chunk_size;
> > +	/**
> > +	 * @initial_xmit_delay_high:
> > +	 * PPS16[1:0] - Most Significant two bits of initial transmission delay.
> > +	 * It specifies the number of pixel times that the encoder waits before
> > +	 * transmitting data from its rate buffer.
> > +	 * PPS16[7:2] - Reserved
> > +	 */
> > +	u8 initial_xmit_delay_high;
> > +	/**
> > +	 * @initial_xmit_delay_low:
> > +	 * PPS17[7:0] - Least significant 8 bits of initial transmission delay.
> > +	 */
> > +	u8 initial_xmit_delay_low;
> > +	/**
> > +	 * @initial_dec_delay:
> > +	 *
> > +	 * PPS18[7:0], PPS19[7:0] - Initial decoding delay which is the number
> > +	 * of pixel times that the decoder accumulates data in its rate buffer
> > +	 * before starting to decode and output pixels.
> > +	 */
> > +	__be16 initial_dec_delay;
> > +	/**
> > +	 * @pps20_reserved:
> > +	 *
> > +	 * PPS20[7:0] - Reserved
> > +	 */
> > +	u8 pps20_reserved;
> > +	/**
> > +	 * @initial_scale_value:
> > +	 * PPS21[5:0] - Initial rcXformScale factor used at beginning
> > +	 * of a slice.
> > +	 * PPS21[7:6] - Reserved
> > +	 */
> > +	u8 initial_scale_value;
> > +	/**
> > +	 * @scale_increment_interval:
> > +	 * PPS22[7:0], PPS23[7:0] - Number of group times between incrementing
> > +	 * the rcXformScale factor at end of a slice.
> > +	 */
> > +	__be16 scale_increment_interval;
> > +	/**
> > +	 * @scale_decrement_interval_high:
> > +	 * PPS24[3:0] - Higher 4 bits indicating number of group times between
> > +	 * decrementing the rcXformScale factor at beginning of a slice.
> > +	 * PPS24[7:4] - Reserved
> > +	 */
> > +	u8 scale_decrement_interval_high;
> > +	/**
> > +	 * @scale_decrement_interval_low:
> > +	 * PPS25[7:0] - Lower 8 bits of scale decrement interval
> > +	 */
> > +	u8 scale_decrement_interval_low;
> > +	/**
> > +	 * @pps26_reserved:
> > +	 * PPS26[7:0]
> > +	 */
> > +	u8 pps26_reserved;
> > +	/**
> > +	 * @first_line_bpg_offset:
> > +	 * PPS27[4:0] - Number of additional bits that are allocated
> > +	 * for each group on first line of a slice.
> > +	 * PPS27[7:5] - Reserved
> > +	 */
> > +	u8 first_line_bpg_offset;
> > +	/**
> > +	 * @nfl_bpg_offset:
> > +	 * PPS28[7:0], PPS29[7:0] - Number of bits including frac bits
> > +	 * deallocated for each group for groups after the first line of slice.
> > +	 */
> > +	__be16 nfl_bpg_offset;
> > +	/**
> > +	 * @slice_bpg_offset:
> > +	 * PPS30, PPS31[7:0] - Number of bits that are deallocated for each
> > +	 * group to enforce the slice constraint.
> > +	 */
> > +	__be16 slice_bpg_offset;
> > +	/**
> > +	 * @initial_offset:
> > +	 * PPS32,33[7:0] - Initial value for rcXformOffset
> > +	 */
> > +	__be16 initial_offset;
> > +	/**
> > +	 * @final_offset:
> > +	 * PPS34,35[7:0] - Maximum end-of-slice value for rcXformOffset
> > +	 */
> > +	__be16 final_offset;
> > +	/**
> > +	 * @flatness_min_qp:
> > +	 * PPS36[4:0] - Minimum QP at which flatness is signaled and
> > +	 * flatness QP adjustment is made.
> > +	 * PPS36[7:5] - Reserved
> > +	 */
> > +	u8 flatness_min_qp;
> > +	/**
> > +	 * @flatness_max_qp:
> > +	 * PPS37[4:0] - Max QP at which flatness is signalled and
> > +	 * the flatness adjustment is made.
> > +	 * PPS37[7:5] - Reserved
> > +	 */
> > +	u8 flatness_max_qp;
> > +	/**
> > +	 * @rc_model_size:
> > +	 * PPS38,39[7:0] - Number of bits within RC Model.
> > +	 */
> > +	__be16 rc_model_size;
> > +	/**
> > +	 * @rc_edge_factor:
> > +	 * PPS40[3:0] - Ratio of current activity vs, previous
> > +	 * activity to determine presence of edge.
> > +	 * PPS40[7:4] - Reserved
> > +	 */
> > +	u8 rc_edge_factor;
> > +	/**
> > +	 * @rc_quant_incr_limit0:
> > +	 * PPS41[4:0] - QP threshold used in short term RC
> > +	 * PPS41[7:5] - Reserved
> > +	 */
> > +	u8 rc_quant_incr_limit0;
> > +	/**
> > +	 * @rc_quant_incr_limit1:
> > +	 * PPS42[4:0] - QP threshold used in short term RC
> > +	 * PPS42[7:5] - Reserved
> > +	 */
> > +	u8 rc_quant_incr_limit1;
> > +	/**
> > +	 * @rc_tgt_offset:
> > +	 * PPS43[3:0] - Lower end of the variability range around the target
> > +	 * bits per group that is allowed by short term RC.
> > +	 * PPS43[7:4]- Upper end of the variability range around the target
> > +	 * bits per group that i allowed by short term rc.
> > +	 */
> > +	u8 rc_tgt_offset;
> > +	/**
> > +	 * @rc_buf_thresh:
> > +	 * PPS44[7:0] - PPS57[7:0] - Specifies the thresholds in RC model for
> > +	 * the 15 ranges defined by 14 thresholds.
> > +	 */
> > +	u8 rc_buf_thresh[DSC_NUM_BUF_RANGES - 1];
> > +	/**
> > +	 * @rc_range_parameters:
> > +	 * PPS58[7:0] - PPS87[7:0]
> > +	 * Parameters that correspond to each of the 15 ranges.
> > +	 */
> > +	__be16 rc_range_parameters[DSC_NUM_BUF_RANGES];
> > +	/**
> > +	 * @native_422_420:
> > +	 * PPS88[0] - 0 = Native 4:2:2 not used
> > +	 * 1 = Native 4:2:2 used
> > +	 * PPS88[1] - 0 = Native 4:2:0 not use
> > +	 * 1 = Native 4:2:0 used
> > +	 * PPS88[7:2] - Reserved 6 bits
> > +	 */
> > +	u8 native_422_420;
> > +	/**
> > +	 * @second_line_bpg_offset:
> > +	 * PPS89[4:0] - Additional bits/group budget for the
> > +	 * second line of a slice in Native 4:2:0 mode.
> > +	 * Set to 0 if DSC minor version is 1 or native420 is 0.
> > +	 * PPS89[7:5] - Reserved
> > +	 */
> > +	u8 second_line_bpg_offset;
> > +	/**
> > +	 * @nsl_bpg_offset:
> > +	 * PPS90[7:0], PPS91[7:0] - Number of bits that are deallocated
> > +	 * for each group that is not in the second line of a slice.
> > +	 */
> > +	__be16 nsl_bpg_offset;
> > +	/**
> > +	 * @second_line_offset_adj:
> > +	 * PPS92[7:0], PPS93[7:0] - Used as offset adjustment for the second
> > +	 * line in Native 4:2:0 mode.
> > +	 */
> > +	__be16 second_line_offset_adj;
> > +	/**
> > +	 * @pps_long_94_reserved:
> > +	 * PPS 94, 95, 96, 97 - Reserved
> > +	 */
> > +	u32 pps_long_94_reserved;
> > +	/**
> > +	 * @pps_long_98_reserved:
> > +	 * PPS 98, 99, 100, 101 - Reserved
> > +	 */
> > +	u32 pps_long_98_reserved;
> > +	/**
> > +	 * @pps_long_102_reserved:
> > +	 * PPS 102, 103, 104, 105 - Reserved
> > +	 */
> > +	u32 pps_long_102_reserved;
> > +	/**
> > +	 * @pps_long_106_reserved:
> > +	 * PPS 106, 107, 108, 109 - reserved
> > +	 */
> > +	u32 pps_long_106_reserved;
> > +	/**
> > +	 * @pps_long_110_reserved:
> > +	 * PPS 110, 111, 112, 113 - reserved
> > +	 */
> > +	u32 pps_long_110_reserved;
> > +	/**
> > +	 * @pps_long_114_reserved:
> > +	 * PPS 114 - 117 - reserved
> > +	 */
> > +	u32 pps_long_114_reserved;
> > +	/**
> > +	 * @pps_long_118_reserved:
> > +	 * PPS 118 - 121 - reserved
> > +	 */
> > +	u32 pps_long_118_reserved;
> > +	/**
> > +	 * @pps_long_122_reserved:
> > +	 * PPS 122- 125 - reserved
> > +	 */
> > +	u32 pps_long_122_reserved;
> > +	/**
> > +	 * @pps_short_126_reserved:
> > +	 * PPS 126, 127 - reserved
> > +	 */
> > +	__be16 pps_short_126_reserved;
> > +};
> > +
> > +/**
> > + * struct drm_dsc_pps_infoframe - DSC infoframe carrying the Picture Parameter
> > + * Set Metadata
> > + *
> > + * This structure represents the DSC PPS infoframe required to send the Picture
> > + * Parameter Set metadata required before enabling VESA Display Stream
> > + * Compression. This is based on the DP Secondary Data Packet structure and
> > + * comprises of SDP Header as defined in drm_dp_helper.h and PPS payload.
> > + *
> > + * @pps_header:
> > + *
> 
> What's with the newline and blank line here? Maybe put the member docs
> next to the member itself?
>

Yea makes sense will remove the newline and blank line.

Manasi
 
> > + * Header for PPS as per DP SDP header format
> > + *
> > + * @pps_payload:
> > + *
> > + * PPS payload fields as per DSC specification Table 4-1
> > + */
> > +struct drm_dsc_pps_infoframe {
> > +	struct dp_sdp_header pps_header;
> > +	struct picture_parameter_set pps_payload;
> > +} __packed;
> > +
> > +#endif /* _DRM_DSC_H_ */
> > -- 
> > 2.18.0
> 
> -- 
> Ville Syrjälä
> Intel
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