path: root/drivers/gpu/drm/amd/display/dc/dsc/dc_dsc.c

/*
 * Copyright 2019 Advanced Micro Devices, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 *
 * Author: AMD
 */

#include <drm/display/drm_dp_helper.h>
#include <drm/display/drm_dsc_helper.h>
#include "dc_hw_types.h"
#include "dsc.h"
#include "dc.h"
#include "rc_calc.h"
#include "fixed31_32.h"

/* This module's internal functions */

/* default DSC policy target bitrate limit is 16bpp */
static uint32_t dsc_policy_max_target_bpp_limit = 16;

/* default DSC policy enables DSC only when needed */
static bool dsc_policy_enable_dsc_when_not_needed;

static bool dsc_policy_disable_dsc_stream_overhead;

static bool disable_128b_132b_stream_overhead;

#ifndef MAX
#define MAX(X, Y) ((X) > (Y) ? (X) : (Y))
#endif
#ifndef MIN
#define MIN(X, Y) ((X) < (Y) ? (X) : (Y))
#endif

/* Need to account for padding due to pixel-to-symbol packing
 * for uncompressed 128b/132b streams.
 */
static uint32_t apply_128b_132b_stream_overhead(
	const struct dc_crtc_timing *timing, const uint32_t kbps)
{
	uint32_t total_kbps = kbps;

	if (disable_128b_132b_stream_overhead)
		return kbps;

	if (!timing->flags.DSC) {
		struct fixed31_32 bpp;
		struct fixed31_32 overhead_factor;

		bpp = dc_fixpt_from_int(kbps);
		bpp = dc_fixpt_div_int(bpp, timing->pix_clk_100hz / 10);

		/* Symbols_per_HActive = HActive * bpp / (4 lanes * 32-bit symbol size)
		 * Overhead_factor = ceil(Symbols_per_HActive) / Symbols_per_HActive
		 */
		overhead_factor = dc_fixpt_from_int(timing->h_addressable);
		overhead_factor = dc_fixpt_mul(overhead_factor, bpp);
		overhead_factor = dc_fixpt_div_int(overhead_factor, 128);
		overhead_factor = dc_fixpt_div(
			dc_fixpt_from_int(dc_fixpt_ceil(overhead_factor)),
			overhead_factor);

		total_kbps = dc_fixpt_ceil(
			dc_fixpt_mul_int(overhead_factor, total_kbps));
	}

	return total_kbps;
}

uint32_t dc_bandwidth_in_kbps_from_timing(
	const struct dc_crtc_timing *timing,
	const enum dc_link_encoding_format link_encoding)
{
	uint32_t bits_per_channel = 0;
	uint32_t kbps;

	if (timing->flags.DSC)
		return dc_dsc_stream_bandwidth_in_kbps(timing,
				timing->dsc_cfg.bits_per_pixel,
				timing->dsc_cfg.num_slices_h,
				timing->dsc_cfg.is_dp);

	switch (timing->display_color_depth) {
	case COLOR_DEPTH_666:
		bits_per_channel = 6;
		break;
	case COLOR_DEPTH_888:
		bits_per_channel = 8;
		break;
	case COLOR_DEPTH_101010:
		bits_per_channel = 10;
		break;
	case COLOR_DEPTH_121212:
		bits_per_channel = 12;
		break;
	case COLOR_DEPTH_141414:
		bits_per_channel = 14;
		break;
	case COLOR_DEPTH_161616:
		bits_per_channel = 16;
		break;
	default:
		ASSERT(bits_per_channel != 0);
		bits_per_channel = 8;
		break;
	}

	kbps = timing->pix_clk_100hz / 10;
	kbps *= bits_per_channel;

	if (timing->flags.Y_ONLY != 1) {
		/*Only YOnly make reduce bandwidth by 1/3 compares to RGB*/
		kbps *= 3;
		if (timing->pixel_encoding == PIXEL_ENCODING_YCBCR420)
			kbps /= 2;
		else if (timing->pixel_encoding ==