linux-imx

// 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