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- // SPDX-License-Identifier: MIT
- /*
- * 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_print.h>
- #include <drm/drm_dp_helper.h>
- #include <drm/drm_dsc.h>
- /**
- * DOC: dsc helpers
- *
- * VESA specification for DP 1.4 adds a new feature called Display Stream
- * Compression (DSC) used to compress the pixel bits before sending it on
- * DP/eDP/MIPI DSI interface. DSC is required to be enabled so that the existing
- * display interfaces can support high resolutions at higher frames rates uisng
- * the maximum available link capacity of these interfaces.
- *
- * 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_header: Secondary data packet header for DSC Picture
- * Parameter Set as defined in &struct dp_sdp_header
- *
- * DP 1.4 spec defines the secondary data packet for sending the
- * picture parameter infoframes from the source to the sink.
- * This function populates the SDP header defined in
- * &struct dp_sdp_header.
- */
- void drm_dsc_dp_pps_header_init(struct dp_sdp_header *pps_header)
- {
- memset(pps_header, 0, sizeof(*pps_header));
- pps_header->HB1 = DP_SDP_PPS;
- pps_header->HB2 = DP_SDP_PPS_HEADER_PAYLOAD_BYTES_MINUS_1;
- }
- EXPORT_SYMBOL(drm_dsc_dp_pps_header_init);
- /**
- * drm_dsc_pps_payload_pack() - Populates the DSC PPS
- *
- * @pps_payload:
- * Bitwise struct for DSC Picture Parameter Set. This is defined
- * by &struct drm_dsc_picture_parameter_set
- * @dsc_cfg:
- * DSC Configuration data filled by driver as defined by
- * &struct drm_dsc_config
- *
- * DSC source device sends a picture parameter set (PPS) containing the
- * information required by the sink to decode the compressed frame. Driver
- * populates the DSC PPS struct 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 big endian format for fields
- * that span more than 1 byte.
- */
- void drm_dsc_pps_payload_pack(struct drm_dsc_picture_parameter_set *pps_payload,
- const struct drm_dsc_config *dsc_cfg)
- {
- int i;
- /* Protect against someone accidently changing struct size */
- BUILD_BUG_ON(sizeof(*pps_payload) !=
- DP_SDP_PPS_HEADER_PAYLOAD_BYTES_MINUS_1 + 1);
- memset(pps_payload, 0, sizeof(*pps_payload));
- /* PPS 0 */
- 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_payload->pps_3 =
- dsc_cfg->line_buf_depth |
- dsc_cfg->bits_per_component << DSC_PPS_BPC_SHIFT;
- /* PPS 4 */
- 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->simple_422 << 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_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_payload->pic_height = cpu_to_be16(dsc_cfg->pic_height);
- /* PPS 8, 9 */
- pps_payload->pic_width = cpu_to_be16(dsc_cfg->pic_width);
- /* PPS 10, 11 */
- pps_payload->slice_height = cpu_to_be16(dsc_cfg->slice_height);
- /* PPS 12, 13 */
- pps_payload->slice_width = cpu_to_be16(dsc_cfg->slice_width);
- /* PPS 14, 15 */
- pps_payload->chunk_size = cpu_to_be16(dsc_cfg->slice_chunk_size);
- /* PPS 16 */
- 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_payload->initial_xmit_delay_low =
- (dsc_cfg->initial_xmit_delay & DSC_PPS_LSB_MASK);
- /* PPS 18, 19 */
- pps_payload->initial_dec_delay =
- cpu_to_be16(dsc_cfg->initial_dec_delay);
- /* PPS 20 is 0 */
- /* PPS 21 */
- pps_payload->initial_scale_value =
- dsc_cfg->initial_scale_value;
- /* PPS 22, 23 */
- pps_payload->scale_increment_interval =
- cpu_to_be16(dsc_cfg->scale_increment_interval);
- /* PPS 24 */
- 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_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_payload->first_line_bpg_offset =
- dsc_cfg->first_line_bpg_offset;
- /* PPS 28, 29 */
- pps_payload->nfl_bpg_offset =
- cpu_to_be16(dsc_cfg->nfl_bpg_offset);
- /* PPS 30, 31 */
- pps_payload->slice_bpg_offset =
- cpu_to_be16(dsc_cfg->slice_bpg_offset);
- /* PPS 32, 33 */
- pps_payload->initial_offset =
- cpu_to_be16(dsc_cfg->initial_offset);
- /* PPS 34, 35 */
- pps_payload->final_offset = cpu_to_be16(dsc_cfg->final_offset);
- /* PPS 36 */
- pps_payload->flatness_min_qp = dsc_cfg->flatness_min_qp;
- /* PPS 37 */
- pps_payload->flatness_max_qp = dsc_cfg->flatness_max_qp;
- /* PPS 38, 39 */
- pps_payload->rc_model_size =
- cpu_to_be16(DSC_RC_MODEL_SIZE_CONST);
- /* PPS 40 */
- pps_payload->rc_edge_factor = DSC_RC_EDGE_FACTOR_CONST;
- /* PPS 41 */
- pps_payload->rc_quant_incr_limit0 =
- dsc_cfg->rc_quant_incr_limit0;
- /* PPS 42 */
- pps_payload->rc_quant_incr_limit1 =
- dsc_cfg->rc_quant_incr_limit1;
- /* PPS 43 */
- 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_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_payload->rc_range_parameters[i] =
- cpu_to_be16((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 88 */
- pps_payload->native_422_420 = dsc_cfg->native_422 |
- dsc_cfg->native_420 << DSC_PPS_NATIVE_420_SHIFT;
- /* PPS 89 */
- pps_payload->second_line_bpg_offset =
- dsc_cfg->second_line_bpg_offset;
- /* PPS 90, 91 */
- pps_payload->nsl_bpg_offset =
- cpu_to_be16(dsc_cfg->nsl_bpg_offset);
- /* PPS 92, 93 */
- 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_payload_pack);
- /**
- * drm_dsc_compute_rc_parameters() - Write rate control
- * parameters to the dsc configuration defined in
- * &struct drm_dsc_config in accordance with the DSC 1.2
- * specification. Some configuration fields must be present
- * beforehand.
- *
- * @vdsc_cfg:
- * DSC Configuration data partially filled by driver
- */
- int drm_dsc_compute_rc_parameters(struct drm_dsc_config *vdsc_cfg)
- {
- unsigned long groups_per_line = 0;
- unsigned long groups_total = 0;
- unsigned long num_extra_mux_bits = 0;
- unsigned long slice_bits = 0;
- unsigned long hrd_delay = 0;
- unsigned long final_scale = 0;
- unsigned long rbs_min = 0;
- if (vdsc_cfg->native_420 || vdsc_cfg->native_422) {
- /* Number of groups used to code each line of a slice */
- groups_per_line = DIV_ROUND_UP(vdsc_cfg->slice_width / 2,
- DSC_RC_PIXELS_PER_GROUP);
- /* chunksize in Bytes */
- vdsc_cfg->slice_chunk_size = DIV_ROUND_UP(vdsc_cfg->slice_width / 2 *
- vdsc_cfg->bits_per_pixel,
- (8 * 16));
- } else {
- /* Number of groups used to code each line of a slice */
- groups_per_line = DIV_ROUND_UP(vdsc_cfg->slice_width,
- DSC_RC_PIXELS_PER_GROUP);
- /* chunksize in Bytes */
- vdsc_cfg->slice_chunk_size = DIV_ROUND_UP(vdsc_cfg->slice_width *
- vdsc_cfg->bits_per_pixel,
- (8 * 16));
- }
- if (vdsc_cfg->convert_rgb)
- num_extra_mux_bits = 3 * (vdsc_cfg->mux_word_size +
- (4 * vdsc_cfg->bits_per_component + 4)
- - 2);
- else if (vdsc_cfg->native_422)
- num_extra_mux_bits = 4 * vdsc_cfg->mux_word_size +
- (4 * vdsc_cfg->bits_per_component + 4) +
- 3 * (4 * vdsc_cfg->bits_per_component) - 2;
- else
- num_extra_mux_bits = 3 * vdsc_cfg->mux_word_size +
- (4 * vdsc_cfg->bits_per_component + 4) +
- 2 * (4 * vdsc_cfg->bits_per_component) - 2;
- /* Number of bits in one Slice */
- slice_bits = 8 * vdsc_cfg->slice_chunk_size * vdsc_cfg->slice_height;
- while ((num_extra_mux_bits > 0) &&
- ((slice_bits - num_extra_mux_bits) % vdsc_cfg->mux_word_size))
- num_extra_mux_bits--;
- if (groups_per_line < vdsc_cfg->initial_scale_value - 8)
- vdsc_cfg->initial_scale_value = groups_per_line + 8;
- /* scale_decrement_interval calculation according to DSC spec 1.11 */
- if (vdsc_cfg->initial_scale_value > 8)
- vdsc_cfg->scale_decrement_interval = groups_per_line /
- (vdsc_cfg->initial_scale_value - 8);
- else
- vdsc_cfg->scale_decrement_interval = DSC_SCALE_DECREMENT_INTERVAL_MAX;
- vdsc_cfg->final_offset = vdsc_cfg->rc_model_size -
- (vdsc_cfg->initial_xmit_delay *
- vdsc_cfg->bits_per_pixel + 8) / 16 + num_extra_mux_bits;
- if (vdsc_cfg->final_offset >= vdsc_cfg->rc_model_size) {
- DRM_DEBUG_KMS("FinalOfs < RcModelSze for this InitialXmitDelay\n");
- return -ERANGE;
- }
- final_scale = (vdsc_cfg->rc_model_size * 8) /
- (vdsc_cfg->rc_model_size - vdsc_cfg->final_offset);
- if (vdsc_cfg->slice_height > 1)
- /*
- * NflBpgOffset is 16 bit value with 11 fractional bits
- * hence we multiply by 2^11 for preserving the
- * fractional part
- */
- vdsc_cfg->nfl_bpg_offset = DIV_ROUND_UP((vdsc_cfg->first_line_bpg_offset << 11),
- (vdsc_cfg->slice_height - 1));
- else
- vdsc_cfg->nfl_bpg_offset = 0;
- /* Number of groups used to code the entire slice */
- groups_total = groups_per_line * vdsc_cfg->slice_height;
- /* slice_bpg_offset is 16 bit value with 11 fractional bits */
- vdsc_cfg->slice_bpg_offset = DIV_ROUND_UP(((vdsc_cfg->rc_model_size -
- vdsc_cfg->initial_offset +
- num_extra_mux_bits) << 11),
- groups_total);
- if (final_scale > 9) {
- /*
- * ScaleIncrementInterval =
- * finaloffset/((NflBpgOffset + SliceBpgOffset)*8(finalscale - 1.125))
- * as (NflBpgOffset + SliceBpgOffset) has 11 bit fractional value,
- * we need divide by 2^11 from pstDscCfg values
- */
- vdsc_cfg->scale_increment_interval =
- (vdsc_cfg->final_offset * (1 << 11)) /
- ((vdsc_cfg->nfl_bpg_offset +
- vdsc_cfg->slice_bpg_offset) *
- (final_scale - 9));
- } else {
- /*
- * If finalScaleValue is less than or equal to 9, a value of 0 should
- * be used to disable the scale increment at the end of the slice
- */
- vdsc_cfg->scale_increment_interval = 0;
- }
- /*
- * DSC spec mentions that bits_per_pixel specifies the target
- * bits/pixel (bpp) rate that is used by the encoder,
- * in steps of 1/16 of a bit per pixel
- */
- rbs_min = vdsc_cfg->rc_model_size - vdsc_cfg->initial_offset +
- DIV_ROUND_UP(vdsc_cfg->initial_xmit_delay *
- vdsc_cfg->bits_per_pixel, 16) +
- groups_per_line * vdsc_cfg->first_line_bpg_offset;
- hrd_delay = DIV_ROUND_UP((rbs_min * 16), vdsc_cfg->bits_per_pixel);
- vdsc_cfg->rc_bits = (hrd_delay * vdsc_cfg->bits_per_pixel) / 16;
- vdsc_cfg->initial_dec_delay = hrd_delay - vdsc_cfg->initial_xmit_delay;
- return 0;
- }
- EXPORT_SYMBOL(drm_dsc_compute_rc_parameters);
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