1 /*
2  * Copyright 2019 Advanced Micro Devices, Inc.
3  *
4  * Permission is hereby granted, free of charge, to any person obtaining a
5  * copy of this software and associated documentation files (the "Software"),
6  * to deal in the Software without restriction, including without limitation
7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8  * and/or sell copies of the Software, and to permit persons to whom the
9  * Software is furnished to do so, subject to the following conditions:
10  *
11  * The above copyright notice and this permission notice shall be included in
12  * all copies or substantial portions of the Software.
13  *
14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
17  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
18  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
19  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
20  * OTHER DEALINGS IN THE SOFTWARE.
21  *
22  * Author: AMD
23  */
24 
25 #include <drm/drm_dsc.h>
26 #include "dc_hw_types.h"
27 #include "dsc.h"
28 #include <drm/dp/drm_dp_helper.h>
29 #include "dc.h"
30 #include "rc_calc.h"
31 #include "fixed31_32.h"
32 
33 /* This module's internal functions */
34 
35 /* default DSC policy target bitrate limit is 16bpp */
36 static uint32_t dsc_policy_max_target_bpp_limit = 16;
37 
38 /* default DSC policy enables DSC only when needed */
39 static bool dsc_policy_enable_dsc_when_not_needed;
40 
41 static bool dsc_policy_disable_dsc_stream_overhead;
42 
43 #ifndef MAX
44 #define MAX(X, Y) ((X) > (Y) ? (X) : (Y))
45 #endif
46 #ifndef MIN
47 #define MIN(X, Y) ((X) < (Y) ? (X) : (Y))
48 #endif
49 
50 /* Forward Declerations */
51 static bool decide_dsc_bandwidth_range(
52 		const uint32_t min_bpp_x16,
53 		const uint32_t max_bpp_x16,
54 		const uint32_t num_slices_h,
55 		const struct dsc_enc_caps *dsc_caps,
56 		const struct dc_crtc_timing *timing,
57 		struct dc_dsc_bw_range *range);
58 
59 static uint32_t compute_bpp_x16_from_target_bandwidth(
60 		const uint32_t bandwidth_in_kbps,
61 		const struct dc_crtc_timing *timing,
62 		const uint32_t num_slices_h,
63 		const uint32_t bpp_increment_div,
64 		const bool is_dp);
65 
66 static void get_dsc_enc_caps(
67 		const struct display_stream_compressor *dsc,
68 		struct dsc_enc_caps *dsc_enc_caps,
69 		int pixel_clock_100Hz);
70 
71 static bool intersect_dsc_caps(
72 		const struct dsc_dec_dpcd_caps *dsc_sink_caps,
73 		const struct dsc_enc_caps *dsc_enc_caps,
74 		enum dc_pixel_encoding pixel_encoding,
75 		struct dsc_enc_caps *dsc_common_caps);
76 
77 static bool setup_dsc_config(
78 		const struct dsc_dec_dpcd_caps *dsc_sink_caps,
79 		const struct dsc_enc_caps *dsc_enc_caps,
80 		int target_bandwidth_kbps,
81 		const struct dc_crtc_timing *timing,
82 		int min_slice_height_override,
83 		int max_dsc_target_bpp_limit_override_x16,
84 		struct dc_dsc_config *dsc_cfg);
85 
86 static bool dsc_buff_block_size_from_dpcd(int dpcd_buff_block_size, int *buff_block_size)
87 {
88 
89 	switch (dpcd_buff_block_size) {
90 	case DP_DSC_RC_BUF_BLK_SIZE_1:
91 		*buff_block_size = 1024;
92 		break;
93 	case DP_DSC_RC_BUF_BLK_SIZE_4:
94 		*buff_block_size = 4 * 1024;
95 		break;
96 	case DP_DSC_RC_BUF_BLK_SIZE_16:
97 		*buff_block_size = 16 * 1024;
98 		break;
99 	case DP_DSC_RC_BUF_BLK_SIZE_64:
100 		*buff_block_size = 64 * 1024;
101 		break;
102 	default: {
103 			dm_error("%s: DPCD DSC buffer size not recognized.\n", __func__);
104 			return false;
105 		}
106 	}
107 
108 	return true;
109 }
110 
111 
112 static bool dsc_line_buff_depth_from_dpcd(int dpcd_line_buff_bit_depth, int *line_buff_bit_depth)
113 {
114 	if (0 <= dpcd_line_buff_bit_depth && dpcd_line_buff_bit_depth <= 7)
115 		*line_buff_bit_depth = dpcd_line_buff_bit_depth + 9;
116 	else if (dpcd_line_buff_bit_depth == 8)
117 		*line_buff_bit_depth = 8;
118 	else {
119 		dm_error("%s: DPCD DSC buffer depth not recognized.\n", __func__);
120 		return false;
121 	}
122 
123 	return true;
124 }
125 
126 
127 static bool dsc_throughput_from_dpcd(int dpcd_throughput, int *throughput)
128 {
129 	switch (dpcd_throughput) {
130 	case DP_DSC_THROUGHPUT_MODE_0_UNSUPPORTED:
131 		*throughput = 0;
132 		break;
133 	case DP_DSC_THROUGHPUT_MODE_0_170:
134 		*throughput = 170;
135 		break;
136 	case DP_DSC_THROUGHPUT_MODE_0_340:
137 		*throughput = 340;
138 		break;
139 	case DP_DSC_THROUGHPUT_MODE_0_400:
140 		*throughput = 400;
141 		break;
142 	case DP_DSC_THROUGHPUT_MODE_0_450:
143 		*throughput = 450;
144 		break;
145 	case DP_DSC_THROUGHPUT_MODE_0_500:
146 		*throughput = 500;
147 		break;
148 	case DP_DSC_THROUGHPUT_MODE_0_550:
149 		*throughput = 550;
150 		break;
151 	case DP_DSC_THROUGHPUT_MODE_0_600:
152 		*throughput = 600;
153 		break;
154 	case DP_DSC_THROUGHPUT_MODE_0_650:
155 		*throughput = 650;
156 		break;
157 	case DP_DSC_THROUGHPUT_MODE_0_700:
158 		*throughput = 700;
159 		break;
160 	case DP_DSC_THROUGHPUT_MODE_0_750:
161 		*throughput = 750;
162 		break;
163 	case DP_DSC_THROUGHPUT_MODE_0_800:
164 		*throughput = 800;
165 		break;
166 	case DP_DSC_THROUGHPUT_MODE_0_850:
167 		*throughput = 850;
168 		break;
169 	case DP_DSC_THROUGHPUT_MODE_0_900:
170 		*throughput = 900;
171 		break;
172 	case DP_DSC_THROUGHPUT_MODE_0_950:
173 		*throughput = 950;
174 		break;
175 	case DP_DSC_THROUGHPUT_MODE_0_1000:
176 		*throughput = 1000;
177 		break;
178 	default: {
179 			dm_error("%s: DPCD DSC throughput mode not recognized.\n", __func__);
180 			return false;
181 		}
182 	}
183 
184 	return true;
185 }
186 
187 
188 static bool dsc_bpp_increment_div_from_dpcd(uint8_t bpp_increment_dpcd, uint32_t *bpp_increment_div)
189 {
190 	// Mask bpp increment dpcd field to avoid reading other fields
191 	bpp_increment_dpcd &= 0x7;
192 
193 	switch (bpp_increment_dpcd) {
194 	case 0:
195 		*bpp_increment_div = 16;
196 		break;
197 	case 1:
198 		*bpp_increment_div = 8;
199 		break;
200 	case 2:
201 		*bpp_increment_div = 4;
202 		break;
203 	case 3:
204 		*bpp_increment_div = 2;
205 		break;
206 	case 4:
207 		*bpp_increment_div = 1;
208 		break;
209 	default: {
210 		dm_error("%s: DPCD DSC bits-per-pixel increment not recognized.\n", __func__);
211 		return false;
212 	}
213 	}
214 
215 	return true;
216 }
217 
218 
219 
220 bool dc_dsc_parse_dsc_dpcd(const struct dc *dc,
221 		const uint8_t *dpcd_dsc_basic_data,
222 		const uint8_t *dpcd_dsc_branch_decoder_caps,
223 		struct dsc_dec_dpcd_caps *dsc_sink_caps)
224 {
225 	if (!dpcd_dsc_basic_data)
226 		return false;
227 
228 	dsc_sink_caps->is_dsc_supported =
229 		(dpcd_dsc_basic_data[DP_DSC_SUPPORT - DP_DSC_SUPPORT] & DP_DSC_DECOMPRESSION_IS_SUPPORTED) != 0;
230 	if (!dsc_sink_caps->is_dsc_supported)
231 		return false;
232 
233 	dsc_sink_caps->dsc_version = dpcd_dsc_basic_data[DP_DSC_REV - DP_DSC_SUPPORT];
234 
235 	{
236 		int buff_block_size;
237 		int buff_size;
238 
239 		if (!dsc_buff_block_size_from_dpcd(dpcd_dsc_basic_data[DP_DSC_RC_BUF_BLK_SIZE - DP_DSC_SUPPORT],
240 										   &buff_block_size))
241 			return false;
242 
243 		buff_size = dpcd_dsc_basic_data[DP_DSC_RC_BUF_SIZE - DP_DSC_SUPPORT] + 1;
244 		dsc_sink_caps->rc_buffer_size = buff_size * buff_block_size;
245 	}
246 
247 	dsc_sink_caps->slice_caps1.raw = dpcd_dsc_basic_data[DP_DSC_SLICE_CAP_1 - DP_DSC_SUPPORT];
248 	if (!dsc_line_buff_depth_from_dpcd(dpcd_dsc_basic_data[DP_DSC_LINE_BUF_BIT_DEPTH - DP_DSC_SUPPORT],
249 									   &dsc_sink_caps->lb_bit_depth))
250 		return false;
251 
252 	dsc_sink_caps->is_block_pred_supported =
253 		(dpcd_dsc_basic_data[DP_DSC_BLK_PREDICTION_SUPPORT - DP_DSC_SUPPORT] &
254 		 DP_DSC_BLK_PREDICTION_IS_SUPPORTED) != 0;
255 
256 	dsc_sink_caps->edp_max_bits_per_pixel =
257 		dpcd_dsc_basic_data[DP_DSC_MAX_BITS_PER_PIXEL_LOW - DP_DSC_SUPPORT] |
258 		dpcd_dsc_basic_data[DP_DSC_MAX_BITS_PER_PIXEL_HI - DP_DSC_SUPPORT] << 8;
259 
260 	dsc_sink_caps->color_formats.raw = dpcd_dsc_basic_data[DP_DSC_DEC_COLOR_FORMAT_CAP - DP_DSC_SUPPORT];
261 	dsc_sink_caps->color_depth.raw = dpcd_dsc_basic_data[DP_DSC_DEC_COLOR_DEPTH_CAP - DP_DSC_SUPPORT];
262 
263 	{
264 		int dpcd_throughput = dpcd_dsc_basic_data[DP_DSC_PEAK_THROUGHPUT - DP_DSC_SUPPORT];
265 
266 		if (!dsc_throughput_from_dpcd(dpcd_throughput & DP_DSC_THROUGHPUT_MODE_0_MASK,
267 									  &dsc_sink_caps->throughput_mode_0_mps))
268 			return false;
269 
270 		dpcd_throughput = (dpcd_throughput & DP_DSC_THROUGHPUT_MODE_1_MASK) >> DP_DSC_THROUGHPUT_MODE_1_SHIFT;
271 		if (!dsc_throughput_from_dpcd(dpcd_throughput, &dsc_sink_caps->throughput_mode_1_mps))
272 			return false;
273 	}
274 
275 	dsc_sink_caps->max_slice_width = dpcd_dsc_basic_data[DP_DSC_MAX_SLICE_WIDTH - DP_DSC_SUPPORT] * 320;
276 	dsc_sink_caps->slice_caps2.raw = dpcd_dsc_basic_data[DP_DSC_SLICE_CAP_2 - DP_DSC_SUPPORT];
277 
278 	if (!dsc_bpp_increment_div_from_dpcd(dpcd_dsc_basic_data[DP_DSC_BITS_PER_PIXEL_INC - DP_DSC_SUPPORT],
279 										 &dsc_sink_caps->bpp_increment_div))
280 		return false;
281 
282 	if (dc->debug.dsc_bpp_increment_div) {
283 		/* dsc_bpp_increment_div should onl be 1, 2, 4, 8 or 16, but rather than rejecting invalid values,
284 		 * we'll accept all and get it into range. This also makes the above check against 0 redundant,
285 		 * but that one stresses out the override will be only used if it's not 0.
286 		 */
287 		if (dc->debug.dsc_bpp_increment_div >= 1)
288 			dsc_sink_caps->bpp_increment_div = 1;
289 		if (dc->debug.dsc_bpp_increment_div >= 2)
290 			dsc_sink_caps->bpp_increment_div = 2;
291 		if (dc->debug.dsc_bpp_increment_div >= 4)
292 			dsc_sink_caps->bpp_increment_div = 4;
293 		if (dc->debug.dsc_bpp_increment_div >= 8)
294 			dsc_sink_caps->bpp_increment_div = 8;
295 		if (dc->debug.dsc_bpp_increment_div >= 16)
296 			dsc_sink_caps->bpp_increment_div = 16;
297 	}
298 
299 	/* Extended caps */
300 	if (dpcd_dsc_branch_decoder_caps == NULL) { // branch decoder DPCD DSC data can be null for non branch device
301 		dsc_sink_caps->branch_overall_throughput_0_mps = 0;
302 		dsc_sink_caps->branch_overall_throughput_1_mps = 0;
303 		dsc_sink_caps->branch_max_line_width = 0;
304 		return true;
305 	}
306 
307 	dsc_sink_caps->branch_overall_throughput_0_mps =
308 		dpcd_dsc_branch_decoder_caps[DP_DSC_BRANCH_OVERALL_THROUGHPUT_0 - DP_DSC_BRANCH_OVERALL_THROUGHPUT_0];
309 	if (dsc_sink_caps->branch_overall_throughput_0_mps == 0)
310 		dsc_sink_caps->branch_overall_throughput_0_mps = 0;
311 	else if (dsc_sink_caps->branch_overall_throughput_0_mps == 1)
312 		dsc_sink_caps->branch_overall_throughput_0_mps = 680;
313 	else {
314 		dsc_sink_caps->branch_overall_throughput_0_mps *= 50;
315 		dsc_sink_caps->branch_overall_throughput_0_mps += 600;
316 	}
317 
318 	dsc_sink_caps->branch_overall_throughput_1_mps =
319 		dpcd_dsc_branch_decoder_caps[DP_DSC_BRANCH_OVERALL_THROUGHPUT_1 - DP_DSC_BRANCH_OVERALL_THROUGHPUT_0];
320 	if (dsc_sink_caps->branch_overall_throughput_1_mps == 0)
321 		dsc_sink_caps->branch_overall_throughput_1_mps = 0;
322 	else if (dsc_sink_caps->branch_overall_throughput_1_mps == 1)
323 		dsc_sink_caps->branch_overall_throughput_1_mps = 680;
324 	else {
325 		dsc_sink_caps->branch_overall_throughput_1_mps *= 50;
326 		dsc_sink_caps->branch_overall_throughput_1_mps += 600;
327 	}
328 
329 	dsc_sink_caps->branch_max_line_width =
330 		dpcd_dsc_branch_decoder_caps[DP_DSC_BRANCH_MAX_LINE_WIDTH - DP_DSC_BRANCH_OVERALL_THROUGHPUT_0] * 320;
331 	ASSERT(dsc_sink_caps->branch_max_line_width == 0 || dsc_sink_caps->branch_max_line_width >= 5120);
332 
333 	dsc_sink_caps->is_dp = true;
334 	return true;
335 }
336 
337 
338 /* If DSC is possbile, get DSC bandwidth range based on [min_bpp, max_bpp] target bitrate range and
339  * timing's pixel clock and uncompressed bandwidth.
340  * If DSC is not possible, leave '*range' untouched.
341  */
342 bool dc_dsc_compute_bandwidth_range(
343 		const struct display_stream_compressor *dsc,
344 		uint32_t dsc_min_slice_height_override,
345 		uint32_t min_bpp_x16,
346 		uint32_t max_bpp_x16,
347 		const struct dsc_dec_dpcd_caps *dsc_sink_caps,
348 		const struct dc_crtc_timing *timing,
349 		struct dc_dsc_bw_range *range)
350 {
351 	bool is_dsc_possible = false;
352 	struct dsc_enc_caps dsc_enc_caps;
353 	struct dsc_enc_caps dsc_common_caps;
354 	struct dc_dsc_config config;
355 
356 	get_dsc_enc_caps(dsc, &dsc_enc_caps, timing->pix_clk_100hz);
357 
358 	is_dsc_possible = intersect_dsc_caps(dsc_sink_caps, &dsc_enc_caps,
359 			timing->pixel_encoding, &dsc_common_caps);
360 
361 	if (is_dsc_possible)
362 		is_dsc_possible = setup_dsc_config(dsc_sink_caps, &dsc_enc_caps, 0, timing,
363 				dsc_min_slice_height_override, max_bpp_x16, &config);
364 
365 	if (is_dsc_possible)
366 		is_dsc_possible = decide_dsc_bandwidth_range(min_bpp_x16, max_bpp_x16,
367 				config.num_slices_h, &dsc_common_caps, timing, range);
368 
369 	return is_dsc_possible;
370 }
371 
372 static void get_dsc_enc_caps(
373 		const struct display_stream_compressor *dsc,
374 		struct dsc_enc_caps *dsc_enc_caps,
375 		int pixel_clock_100Hz)
376 {
377 	// This is a static HW query, so we can use any DSC
378 
379 	memset(dsc_enc_caps, 0, sizeof(struct dsc_enc_caps));
380 	if (dsc) {
381 		if (!dsc->ctx->dc->debug.disable_dsc)
382 			dsc->funcs->dsc_get_enc_caps(dsc_enc_caps, pixel_clock_100Hz);
383 		if (dsc->ctx->dc->debug.native422_support)
384 			dsc_enc_caps->color_formats.bits.YCBCR_NATIVE_422 = 1;
385 	}
386 }
387 
388 /* Returns 'false' if no intersection was found for at least one capability.
389  * It also implicitly validates some sink caps against invalid value of zero.
390  */
391 static bool intersect_dsc_caps(
392 		const struct dsc_dec_dpcd_caps *dsc_sink_caps,
393 		const struct dsc_enc_caps *dsc_enc_caps,
394 		enum dc_pixel_encoding pixel_encoding,
395 		struct dsc_enc_caps *dsc_common_caps)
396 {
397 	int32_t max_slices;
398 	int32_t total_sink_throughput;
399 
400 	memset(dsc_common_caps, 0, sizeof(struct dsc_enc_caps));
401 
402 	dsc_common_caps->dsc_version = min(dsc_sink_caps->dsc_version, dsc_enc_caps->dsc_version);
403 	if (!dsc_common_caps->dsc_version)
404 		return false;
405 
406 	dsc_common_caps->slice_caps.bits.NUM_SLICES_1 =
407 		dsc_sink_caps->slice_caps1.bits.NUM_SLICES_1 && dsc_enc_caps->slice_caps.bits.NUM_SLICES_1;
408 	dsc_common_caps->slice_caps.bits.NUM_SLICES_2 =
409 		dsc_sink_caps->slice_caps1.bits.NUM_SLICES_2 && dsc_enc_caps->slice_caps.bits.NUM_SLICES_2;
410 	dsc_common_caps->slice_caps.bits.NUM_SLICES_4 =
411 		dsc_sink_caps->slice_caps1.bits.NUM_SLICES_4 && dsc_enc_caps->slice_caps.bits.NUM_SLICES_4;
412 	dsc_common_caps->slice_caps.bits.NUM_SLICES_8 =
413 		dsc_sink_caps->slice_caps1.bits.NUM_SLICES_8 && dsc_enc_caps->slice_caps.bits.NUM_SLICES_8;
414 	if (!dsc_common_caps->slice_caps.raw)
415 		return false;
416 
417 	dsc_common_caps->lb_bit_depth = min(dsc_sink_caps->lb_bit_depth, dsc_enc_caps->lb_bit_depth);
418 	if (!dsc_common_caps->lb_bit_depth)
419 		return false;
420 
421 	dsc_common_caps->is_block_pred_supported =
422 		dsc_sink_caps->is_block_pred_supported && dsc_enc_caps->is_block_pred_supported;
423 
424 	dsc_common_caps->color_formats.raw = dsc_sink_caps->color_formats.raw & dsc_enc_caps->color_formats.raw;
425 	if (!dsc_common_caps->color_formats.raw)
426 		return false;
427 
428 	dsc_common_caps->color_depth.raw = dsc_sink_caps->color_depth.raw & dsc_enc_caps->color_depth.raw;
429 	if (!dsc_common_caps->color_depth.raw)
430 		return false;
431 
432 	max_slices = 0;
433 	if (dsc_common_caps->slice_caps.bits.NUM_SLICES_1)
434 		max_slices = 1;
435 
436 	if (dsc_common_caps->slice_caps.bits.NUM_SLICES_2)
437 		max_slices = 2;
438 
439 	if (dsc_common_caps->slice_caps.bits.NUM_SLICES_4)
440 		max_slices = 4;
441 
442 	total_sink_throughput = max_slices * dsc_sink_caps->throughput_mode_0_mps;
443 	if (pixel_encoding == PIXEL_ENCODING_YCBCR422 || pixel_encoding == PIXEL_ENCODING_YCBCR420)
444 		total_sink_throughput = max_slices * dsc_sink_caps->throughput_mode_1_mps;
445 
446 	dsc_common_caps->max_total_throughput_mps = min(total_sink_throughput, dsc_enc_caps->max_total_throughput_mps);
447 
448 	dsc_common_caps->max_slice_width = min(dsc_sink_caps->max_slice_width, dsc_enc_caps->max_slice_width);
449 	if (!dsc_common_caps->max_slice_width)
450 		return false;
451 
452 	dsc_common_caps->bpp_increment_div = min(dsc_sink_caps->bpp_increment_div, dsc_enc_caps->bpp_increment_div);
453 
454 	// TODO DSC: Remove this workaround for N422 and 420 once it's fixed, or move it to get_dsc_encoder_caps()
455 	if (pixel_encoding == PIXEL_ENCODING_YCBCR422 || pixel_encoding == PIXEL_ENCODING_YCBCR420)
456 		dsc_common_caps->bpp_increment_div = min(dsc_common_caps->bpp_increment_div, (uint32_t)8);
457 
458 	dsc_common_caps->edp_sink_max_bits_per_pixel = dsc_sink_caps->edp_max_bits_per_pixel;
459 	dsc_common_caps->is_dp = dsc_sink_caps->is_dp;
460 	return true;
461 }
462 
463 static inline uint32_t dsc_div_by_10_round_up(uint32_t value)
464 {
465 	return (value + 9) / 10;
466 }
467 
468 static uint32_t compute_bpp_x16_from_target_bandwidth(
469 	const uint32_t bandwidth_in_kbps,
470 	const struct dc_crtc_timing *timing,
471 	const uint32_t num_slices_h,
472 	const uint32_t bpp_increment_div,
473 	const bool is_dp)
474 {
475 	uint32_t overhead_in_kbps;
476 	struct fixed31_32 effective_bandwidth_in_kbps;
477 	struct fixed31_32 bpp_x16;
478 
479 	overhead_in_kbps = dc_dsc_stream_bandwidth_overhead_in_kbps(
480 				timing, num_slices_h, is_dp);
481 	effective_bandwidth_in_kbps = dc_fixpt_from_int(bandwidth_in_kbps);
482 	effective_bandwidth_in_kbps = dc_fixpt_sub_int(effective_bandwidth_in_kbps,
483 			overhead_in_kbps);
484 	bpp_x16 = dc_fixpt_mul_int(effective_bandwidth_in_kbps, 10);
485 	bpp_x16 = dc_fixpt_div_int(bpp_x16, timing->pix_clk_100hz);
486 	bpp_x16 = dc_fixpt_from_int(dc_fixpt_floor(dc_fixpt_mul_int(bpp_x16, bpp_increment_div)));
487 	bpp_x16 = dc_fixpt_div_int(bpp_x16, bpp_increment_div);
488 	bpp_x16 = dc_fixpt_mul_int(bpp_x16, 16);
489 	return dc_fixpt_floor(bpp_x16);
490 }
491 
492 /* Decide DSC bandwidth range based on signal, timing, specs specific and input min and max
493  * requirements.
494  * The range output includes decided min/max target bpp, the respective bandwidth requirements
495  * and native timing bandwidth requirement when DSC is not used.
496  */
497 static bool decide_dsc_bandwidth_range(
498 		const uint32_t min_bpp_x16,
499 		const uint32_t max_bpp_x16,
500 		const uint32_t num_slices_h,
501 		const struct dsc_enc_caps *dsc_caps,
502 		const struct dc_crtc_timing *timing,
503 		struct dc_dsc_bw_range *range)
504 {
505 	uint32_t preferred_bpp_x16 = timing->dsc_fixed_bits_per_pixel_x16;
506 
507 	memset(range, 0, sizeof(*range));
508 
509 	/* apply signal, timing, specs and explicitly specified DSC range requirements */
510 	if (preferred_bpp_x16) {
511 		if (preferred_bpp_x16 <= max_bpp_x16 &&
512 				preferred_bpp_x16 >= min_bpp_x16) {
513 			range->max_target_bpp_x16 = preferred_bpp_x16;
514 			range->min_target_bpp_x16 = preferred_bpp_x16;
515 		}
516 	}
517 	/* TODO - make this value generic to all signal types */
518 	else if (dsc_caps->edp_sink_max_bits_per_pixel) {
519 		/* apply max bpp limitation from edp sink */
520 		range->max_target_bpp_x16 = MIN(dsc_caps->edp_sink_max_bits_per_pixel,
521 				max_bpp_x16);
522 		range->min_target_bpp_x16 = min_bpp_x16;
523 	}
524 	else {
525 		range->max_target_bpp_x16 = max_bpp_x16;
526 		range->min_target_bpp_x16 = min_bpp_x16;
527 	}
528 
529 	/* populate output structure */
530 	if (range->max_target_bpp_x16 >= range->min_target_bpp_x16 && range->min_target_bpp_x16 > 0) {
531 		/* native stream bandwidth */
532 		range->stream_kbps = dc_bandwidth_in_kbps_from_timing(timing);
533 
534 		/* max dsc target bpp */
535 		range->max_kbps = dc_dsc_stream_bandwidth_in_kbps(timing,
536 				range->max_target_bpp_x16, num_slices_h, dsc_caps->is_dp);
537 
538 		/* min dsc target bpp */
539 		range->min_kbps = dc_dsc_stream_bandwidth_in_kbps(timing,
540 				range->min_target_bpp_x16, num_slices_h, dsc_caps->is_dp);
541 	}
542 
543 	return range->max_kbps >= range->min_kbps && range->min_kbps > 0;
544 }
545 
546 /* Decides if DSC should be used and calculates target bpp if it should, applying DSC policy.
547  *
548  * Returns:
549  *     - 'true' if target bpp is decided
550  *     - 'false' if target bpp cannot be decided (e.g. cannot fit even with min DSC bpp),
551  */
552 static bool decide_dsc_target_bpp_x16(
553 		const struct dc_dsc_policy *policy,
554 		const struct dsc_enc_caps *dsc_common_caps,
555 		const int target_bandwidth_kbps,
556 		const struct dc_crtc_timing *timing,
557 		const int num_slices_h,
558 		int *target_bpp_x16)
559 {
560 	struct dc_dsc_bw_range range;
561 
562 	*target_bpp_x16 = 0;
563 
564 	if (decide_dsc_bandwidth_range(policy->min_target_bpp * 16, policy->max_target_bpp * 16,
565 			num_slices_h, dsc_common_caps, timing, &range)) {
566 		if (target_bandwidth_kbps >= range.stream_kbps) {
567 			if (policy->enable_dsc_when_not_needed)
568 				/* enable max bpp even dsc is not needed */
569 				*target_bpp_x16 = range.max_target_bpp_x16;
570 		} else if (target_bandwidth_kbps >= range.max_kbps) {
571 			/* use max target bpp allowed */
572 			*target_bpp_x16 = range.max_target_bpp_x16;
573 		} else if (target_bandwidth_kbps >= range.min_kbps) {
574 			/* use target bpp that can take entire target bandwidth */
575 			*target_bpp_x16 = compute_bpp_x16_from_target_bandwidth(
576 					target_bandwidth_kbps, timing, num_slices_h,
577 					dsc_common_caps->bpp_increment_div,
578 					dsc_common_caps->is_dp);
579 		}
580 	}
581 
582 	return *target_bpp_x16 != 0;
583 }
584 
585 #define MIN_AVAILABLE_SLICES_SIZE  6
586 
587 static int get_available_dsc_slices(union dsc_enc_slice_caps slice_caps, int *available_slices)
588 {
589 	int idx = 0;
590 
591 	memset(available_slices, -1, MIN_AVAILABLE_SLICES_SIZE);
592 
593 	if (slice_caps.bits.NUM_SLICES_1)
594 		available_slices[idx++] = 1;
595 
596 	if (slice_caps.bits.NUM_SLICES_2)
597 		available_slices[idx++] = 2;
598 
599 	if (slice_caps.bits.NUM_SLICES_4)
600 		available_slices[idx++] = 4;
601 
602 	if (slice_caps.bits.NUM_SLICES_8)
603 		available_slices[idx++] = 8;
604 
605 	return idx;
606 }
607 
608 
609 static int get_max_dsc_slices(union dsc_enc_slice_caps slice_caps)
610 {
611 	int max_slices = 0;
612 	int available_slices[MIN_AVAILABLE_SLICES_SIZE];
613 	int end_idx = get_available_dsc_slices(slice_caps, &available_slices[0]);
614 
615 	if (end_idx > 0)
616 		max_slices = available_slices[end_idx - 1];
617 
618 	return max_slices;
619 }
620 
621 
622 // Increment sice number in available sice numbers stops if possible, or just increment if not
623 static int inc_num_slices(union dsc_enc_slice_caps slice_caps, int num_slices)
624 {
625 	// Get next bigger num slices available in common caps
626 	int available_slices[MIN_AVAILABLE_SLICES_SIZE];
627 	int end_idx;
628 	int i;
629 	int new_num_slices = num_slices;
630 
631 	end_idx = get_available_dsc_slices(slice_caps, &available_slices[0]);
632 	if (end_idx == 0) {
633 		// No available slices found
634 		new_num_slices++;
635 		return new_num_slices;
636 	}
637 
638 	// Numbers of slices found - get the next bigger number
639 	for (i = 0; i < end_idx; i++) {
640 		if (new_num_slices < available_slices[i]) {
641 			new_num_slices = available_slices[i];
642 			break;
643 		}
644 	}
645 
646 	if (new_num_slices == num_slices) // No biger number of slices found
647 		new_num_slices++;
648 
649 	return new_num_slices;
650 }
651 
652 
653 // Decrement sice number in available sice numbers stops if possible, or just decrement if not. Stop at zero.
654 static int dec_num_slices(union dsc_enc_slice_caps slice_caps, int num_slices)
655 {
656 	// Get next bigger num slices available in common caps
657 	int available_slices[MIN_AVAILABLE_SLICES_SIZE];
658 	int end_idx;
659 	int i;
660 	int new_num_slices = num_slices;
661 
662 	end_idx = get_available_dsc_slices(slice_caps, &available_slices[0]);
663 	if (end_idx == 0 && new_num_slices > 0) {
664 		// No numbers of slices found
665 		new_num_slices++;
666 		return new_num_slices;
667 	}
668 
669 	// Numbers of slices found - get the next smaller number
670 	for (i = end_idx - 1; i >= 0; i--) {
671 		if (new_num_slices > available_slices[i]) {
672 			new_num_slices = available_slices[i];
673 			break;
674 		}
675 	}
676 
677 	if (new_num_slices == num_slices) {
678 		// No smaller number of slices found
679 		new_num_slices--;
680 		if (new_num_slices < 0)
681 			new_num_slices = 0;
682 	}
683 
684 	return new_num_slices;
685 }
686 
687 
688 // Choose next bigger number of slices if the requested number of slices is not available
689 static int fit_num_slices_up(union dsc_enc_slice_caps slice_caps, int num_slices)
690 {
691 	// Get next bigger num slices available in common caps
692 	int available_slices[MIN_AVAILABLE_SLICES_SIZE];
693 	int end_idx;
694 	int i;
695 	int new_num_slices = num_slices;
696 
697 	end_idx = get_available_dsc_slices(slice_caps, &available_slices[0]);
698 	if (end_idx == 0) {
699 		// No available slices found
700 		new_num_slices++;
701 		return new_num_slices;
702 	}
703 
704 	// Numbers of slices found - get the equal or next bigger number
705 	for (i = 0; i < end_idx; i++) {
706 		if (new_num_slices <= available_slices[i]) {
707 			new_num_slices = available_slices[i];
708 			break;
709 		}
710 	}
711 
712 	return new_num_slices;
713 }
714 
715 
716 /* Attempts to set DSC configuration for the stream, applying DSC policy.
717  * Returns 'true' if successful or 'false' if not.
718  *
719  * Parameters:
720  *
721  * dsc_sink_caps       - DSC sink decoder capabilities (from DPCD)
722  *
723  * dsc_enc_caps        - DSC encoder capabilities
724  *
725  * target_bandwidth_kbps  - Target bandwidth to fit the stream into.
726  *                          If 0, do not calculate target bpp.
727  *
728  * timing              - The stream timing to fit into 'target_bandwidth_kbps' or apply
729  *                       maximum compression to, if 'target_badwidth == 0'
730  *
731  * dsc_cfg             - DSC configuration to use if it was possible to come up with
732  *                       one for the given inputs.
733  *                       The target bitrate after DSC can be calculated by multiplying
734  *                       dsc_cfg.bits_per_pixel (in U6.4 format) by pixel rate, e.g.
735  *
736  *                       dsc_stream_bitrate_kbps = (int)ceil(timing->pix_clk_khz * dsc_cfg.bits_per_pixel / 16.0);
737  */
738 static bool setup_dsc_config(
739 		const struct dsc_dec_dpcd_caps *dsc_sink_caps,
740 		const struct dsc_enc_caps *dsc_enc_caps,
741 		int target_bandwidth_kbps,
742 		const struct dc_crtc_timing *timing,
743 		int min_slice_height_override,
744 		int max_dsc_target_bpp_limit_override_x16,
745 		struct dc_dsc_config *dsc_cfg)
746 {
747 	struct dsc_enc_caps dsc_common_caps;
748 	int max_slices_h;
749 	int min_slices_h;
750 	int num_slices_h;
751 	int pic_width;
752 	int slice_width;
753 	int target_bpp;
754 	int sink_per_slice_throughput_mps;
755 	int branch_max_throughput_mps = 0;
756 	bool is_dsc_possible = false;
757 	int pic_height;
758 	int slice_height;
759 	struct dc_dsc_policy policy;
760 
761 	memset(dsc_cfg, 0, sizeof(struct dc_dsc_config));
762 
763 	dc_dsc_get_policy_for_timing(timing, max_dsc_target_bpp_limit_override_x16, &policy);
764 	pic_width = timing->h_addressable + timing->h_border_left + timing->h_border_right;
765 	pic_height = timing->v_addressable + timing->v_border_top + timing->v_border_bottom;
766 
767 	if (!dsc_sink_caps->is_dsc_supported)
768 		goto done;
769 
770 	if (dsc_sink_caps->branch_max_line_width && dsc_sink_caps->branch_max_line_width < pic_width)
771 		goto done;
772 
773 	// Intersect decoder with encoder DSC caps and validate DSC settings
774 	is_dsc_possible = intersect_dsc_caps(dsc_sink_caps, dsc_enc_caps, timing->pixel_encoding, &dsc_common_caps);
775 	if (!is_dsc_possible)
776 		goto done;
777 
778 	sink_per_slice_throughput_mps = 0;
779 
780 	// Validate available DSC settings against the mode timing
781 
782 	// Validate color format (and pick up the throughput values)
783 	dsc_cfg->ycbcr422_simple = false;
784 	switch (timing->pixel_encoding)	{
785 	case PIXEL_ENCODING_RGB:
786 		is_dsc_possible = (bool)dsc_common_caps.color_formats.bits.RGB;
787 		sink_per_slice_throughput_mps = dsc_sink_caps->throughput_mode_0_mps;
788 		branch_max_throughput_mps = dsc_sink_caps->branch_overall_throughput_0_mps;
789 		break;
790 	case PIXEL_ENCODING_YCBCR444:
791 		is_dsc_possible = (bool)dsc_common_caps.color_formats.bits.YCBCR_444;
792 		sink_per_slice_throughput_mps = dsc_sink_caps->throughput_mode_0_mps;
793 		branch_max_throughput_mps = dsc_sink_caps->branch_overall_throughput_0_mps;
794 		break;
795 	case PIXEL_ENCODING_YCBCR422:
796 		is_dsc_possible = (bool)dsc_common_caps.color_formats.bits.YCBCR_NATIVE_422;
797 		sink_per_slice_throughput_mps = dsc_sink_caps->throughput_mode_1_mps;
798 		branch_max_throughput_mps = dsc_sink_caps->branch_overall_throughput_1_mps;
799 		if (!is_dsc_possible) {
800 			is_dsc_possible = (bool)dsc_common_caps.color_formats.bits.YCBCR_SIMPLE_422;
801 			dsc_cfg->ycbcr422_simple = is_dsc_possible;
802 			sink_per_slice_throughput_mps = dsc_sink_caps->throughput_mode_0_mps;
803 		}
804 		break;
805 	case PIXEL_ENCODING_YCBCR420:
806 		is_dsc_possible = (bool)dsc_common_caps.color_formats.bits.YCBCR_NATIVE_420;
807 		sink_per_slice_throughput_mps = dsc_sink_caps->throughput_mode_1_mps;
808 		branch_max_throughput_mps = dsc_sink_caps->branch_overall_throughput_1_mps;
809 		break;
810 	default:
811 		is_dsc_possible = false;
812 	}
813 
814 	// Validate branch's maximum throughput
815 	if (branch_max_throughput_mps && dsc_div_by_10_round_up(timing->pix_clk_100hz) > branch_max_throughput_mps * 1000)
816 		is_dsc_possible = false;
817 
818 	if (!is_dsc_possible)
819 		goto done;
820 
821 	// Color depth
822 	switch (timing->display_color_depth) {
823 	case COLOR_DEPTH_888:
824 		is_dsc_possible = (bool)dsc_common_caps.color_depth.bits.COLOR_DEPTH_8_BPC;
825 		break;
826 	case COLOR_DEPTH_101010:
827 		is_dsc_possible = (bool)dsc_common_caps.color_depth.bits.COLOR_DEPTH_10_BPC;
828 		break;
829 	case COLOR_DEPTH_121212:
830 		is_dsc_possible = (bool)dsc_common_caps.color_depth.bits.COLOR_DEPTH_12_BPC;
831 		break;
832 	default:
833 		is_dsc_possible = false;
834 	}
835 
836 	if (!is_dsc_possible)
837 		goto done;
838 
839 	// Slice width (i.e. number of slices per line)
840 	max_slices_h = get_max_dsc_slices(dsc_common_caps.slice_caps);
841 
842 	while (max_slices_h > 0) {
843 		if (pic_width % max_slices_h == 0)
844 			break;
845 
846 		max_slices_h = dec_num_slices(dsc_common_caps.slice_caps, max_slices_h);
847 	}
848 
849 	is_dsc_possible = (dsc_common_caps.max_slice_width > 0);
850 	if (!is_dsc_possible)
851 		goto done;
852 
853 	min_slices_h = pic_width / dsc_common_caps.max_slice_width;
854 	if (pic_width % dsc_common_caps.max_slice_width)
855 		min_slices_h++;
856 
857 	min_slices_h = fit_num_slices_up(dsc_common_caps.slice_caps, min_slices_h);
858 
859 	while (min_slices_h <= max_slices_h) {
860 		int pix_clk_per_slice_khz = dsc_div_by_10_round_up(timing->pix_clk_100hz) / min_slices_h;
861 		if (pix_clk_per_slice_khz <= sink_per_slice_throughput_mps * 1000)
862 			break;
863 
864 		min_slices_h = inc_num_slices(dsc_common_caps.slice_caps, min_slices_h);
865 	}
866 
867 	if (pic_width % min_slices_h != 0)
868 		min_slices_h = 0; // DSC TODO: Maybe try increasing the number of slices first?
869 
870 	is_dsc_possible = (min_slices_h <= max_slices_h);
871 
872 	if (min_slices_h == 0 && max_slices_h == 0)
873 		is_dsc_possible = false;
874 
875 	if (!is_dsc_possible)
876 		goto done;
877 
878 	if (policy.use_min_slices_h) {
879 		if (min_slices_h > 0)
880 			num_slices_h = min_slices_h;
881 		else if (max_slices_h > 0) { // Fall back to max slices if min slices is not working out
882 			if (policy.max_slices_h)
883 				num_slices_h = min(policy.max_slices_h, max_slices_h);
884 			else
885 				num_slices_h = max_slices_h;
886 		} else
887 			is_dsc_possible = false;
888 	} else {
889 		if (max_slices_h > 0) {
890 			if (policy.max_slices_h)
891 				num_slices_h = min(policy.max_slices_h, max_slices_h);
892 			else
893 				num_slices_h = max_slices_h;
894 		} else if (min_slices_h > 0) // Fall back to min slices if max slices is not possible
895 			num_slices_h = min_slices_h;
896 		else
897 			is_dsc_possible = false;
898 	}
899 
900 	if (!is_dsc_possible)
901 		goto done;
902 
903 	dsc_cfg->num_slices_h = num_slices_h;
904 	slice_width = pic_width / num_slices_h;
905 
906 	is_dsc_possible = slice_width <= dsc_common_caps.max_slice_width;
907 	if (!is_dsc_possible)
908 		goto done;
909 
910 	// Slice height (i.e. number of slices per column): start with policy and pick the first one that height is divisible by.
911 	// For 4:2:0 make sure the slice height is divisible by 2 as well.
912 	if (min_slice_height_override == 0)
913 		slice_height = min(policy.min_slice_height, pic_height);
914 	else
915 		slice_height = min(min_slice_height_override, pic_height);
916 
917 	while (slice_height < pic_height && (pic_height % slice_height != 0 ||
918 		(timing->pixel_encoding == PIXEL_ENCODING_YCBCR420 && slice_height % 2 != 0)))
919 		slice_height++;
920 
921 	if (timing->pixel_encoding == PIXEL_ENCODING_YCBCR420) // For the case when pic_height < dsc_policy.min_sice_height
922 		is_dsc_possible = (slice_height % 2 == 0);
923 
924 	if (!is_dsc_possible)
925 		goto done;
926 
927 	dsc_cfg->num_slices_v = pic_height/slice_height;
928 
929 	if (target_bandwidth_kbps > 0) {
930 		is_dsc_possible = decide_dsc_target_bpp_x16(
931 				&policy,
932 				&dsc_common_caps,
933 				target_bandwidth_kbps,
934 				timing,
935 				num_slices_h,
936 				&target_bpp);
937 		dsc_cfg->bits_per_pixel = target_bpp;
938 	}
939 	if (!is_dsc_possible)
940 		goto done;
941 
942 	// Final decission: can we do DSC or not?
943 	if (is_dsc_possible) {
944 		// Fill out the rest of DSC settings
945 		dsc_cfg->block_pred_enable = dsc_common_caps.is_block_pred_supported;
946 		dsc_cfg->linebuf_depth = dsc_common_caps.lb_bit_depth;
947 		dsc_cfg->version_minor = (dsc_common_caps.dsc_version & 0xf0) >> 4;
948 		dsc_cfg->is_dp = dsc_sink_caps->is_dp;
949 	}
950 
951 done:
952 	if (!is_dsc_possible)
953 		memset(dsc_cfg, 0, sizeof(struct dc_dsc_config));
954 
955 	return is_dsc_possible;
956 }
957 
958 bool dc_dsc_compute_config(
959 		const struct display_stream_compressor *dsc,
960 		const struct dsc_dec_dpcd_caps *dsc_sink_caps,
961 		uint32_t dsc_min_slice_height_override,
962 		uint32_t max_target_bpp_limit_override,
963 		uint32_t target_bandwidth_kbps,
964 		const struct dc_crtc_timing *timing,
965 		struct dc_dsc_config *dsc_cfg)
966 {
967 	bool is_dsc_possible = false;
968 	struct dsc_enc_caps dsc_enc_caps;
969 
970 	get_dsc_enc_caps(dsc, &dsc_enc_caps, timing->pix_clk_100hz);
971 	is_dsc_possible = setup_dsc_config(dsc_sink_caps,
972 		&dsc_enc_caps,
973 		target_bandwidth_kbps,
974 		timing, dsc_min_slice_height_override,
975 		max_target_bpp_limit_override * 16, dsc_cfg);
976 	return is_dsc_possible;
977 }
978 
979 uint32_t dc_dsc_stream_bandwidth_in_kbps(const struct dc_crtc_timing *timing,
980 	uint32_t bpp_x16, uint32_t num_slices_h, bool is_dp)
981 {
982 	uint32_t overhead_in_kbps;
983 	struct fixed31_32 bpp;
984 	struct fixed31_32 actual_bandwidth_in_kbps;
985 
986 	overhead_in_kbps = dc_dsc_stream_bandwidth_overhead_in_kbps(
987 		timing, num_slices_h, is_dp);
988 	bpp = dc_fixpt_from_fraction(bpp_x16, 16);
989 	actual_bandwidth_in_kbps = dc_fixpt_from_fraction(timing->pix_clk_100hz, 10);
990 	actual_bandwidth_in_kbps = dc_fixpt_mul(actual_bandwidth_in_kbps, bpp);
991 	actual_bandwidth_in_kbps = dc_fixpt_add_int(actual_bandwidth_in_kbps, overhead_in_kbps);
992 	return dc_fixpt_ceil(actual_bandwidth_in_kbps);
993 }
994 
995 uint32_t dc_dsc_stream_bandwidth_overhead_in_kbps(
996 		const struct dc_crtc_timing *timing,
997 		const int num_slices_h,
998 		const bool is_dp)
999 {
1000 	struct fixed31_32 max_dsc_overhead;
1001 	struct fixed31_32 refresh_rate;
1002 
1003 	if (dsc_policy_disable_dsc_stream_overhead || !is_dp)
1004 		return 0;
1005 
1006 	/* use target bpp that can take entire target bandwidth */
1007 	refresh_rate = dc_fixpt_from_int(timing->pix_clk_100hz);
1008 	refresh_rate = dc_fixpt_div_int(refresh_rate, timing->h_total);
1009 	refresh_rate = dc_fixpt_div_int(refresh_rate, timing->v_total);
1010 	refresh_rate = dc_fixpt_mul_int(refresh_rate, 100);
1011 
1012 	max_dsc_overhead = dc_fixpt_from_int(num_slices_h);
1013 	max_dsc_overhead = dc_fixpt_mul_int(max_dsc_overhead, timing->v_total);
1014 	max_dsc_overhead = dc_fixpt_mul_int(max_dsc_overhead, 256);
1015 	max_dsc_overhead = dc_fixpt_div_int(max_dsc_overhead, 1000);
1016 	max_dsc_overhead = dc_fixpt_mul(max_dsc_overhead, refresh_rate);
1017 
1018 	return dc_fixpt_ceil(max_dsc_overhead);
1019 }
1020 
1021 void dc_dsc_get_policy_for_timing(const struct dc_crtc_timing *timing,
1022 		uint32_t max_target_bpp_limit_override_x16,
1023 		struct dc_dsc_policy *policy)
1024 {
1025 	uint32_t bpc = 0;
1026 
1027 	policy->min_target_bpp = 0;
1028 	policy->max_target_bpp = 0;
1029 
1030 	/* DSC Policy: Use minimum number of slices that fits the pixel clock */
1031 	policy->use_min_slices_h = true;
1032 
1033 	/* DSC Policy: Use max available slices
1034 	 * (in our case 4 for or 8, depending on the mode)
1035 	 */
1036 	policy->max_slices_h = 0;
1037 
1038 	/* DSC Policy: Use slice height recommended
1039 	 * by VESA DSC Spreadsheet user guide
1040 	 */
1041 	policy->min_slice_height = 108;
1042 
1043 	/* DSC Policy: follow DP specs with an internal upper limit to 16 bpp
1044 	 * for better interoperability
1045 	 */
1046 	switch (timing->display_color_depth) {
1047 	case COLOR_DEPTH_888:
1048 		bpc = 8;
1049 		break;
1050 	case COLOR_DEPTH_101010:
1051 		bpc = 10;
1052 		break;
1053 	case COLOR_DEPTH_121212:
1054 		bpc = 12;
1055 		break;
1056 	default:
1057 		return;
1058 	}
1059 	switch (timing->pixel_encoding) {
1060 	case PIXEL_ENCODING_RGB:
1061 	case PIXEL_ENCODING_YCBCR444:
1062 	case PIXEL_ENCODING_YCBCR422: /* assume no YCbCr422 native support */
1063 		/* DP specs limits to 8 */
1064 		policy->min_target_bpp = 8;
1065 		/* DP specs limits to 3 x bpc */
1066 		policy->max_target_bpp = 3 * bpc;
1067 		break;
1068 	case PIXEL_ENCODING_YCBCR420:
1069 		/* DP specs limits to 6 */
1070 		policy->min_target_bpp = 6;
1071 		/* DP specs limits to 1.5 x bpc assume bpc is an even number */
1072 		policy->max_target_bpp = bpc * 3 / 2;
1073 		break;
1074 	default:
1075 		return;
1076 	}
1077 
1078 	/* internal upper limit, default 16 bpp */
1079 	if (policy->max_target_bpp > dsc_policy_max_target_bpp_limit)
1080 		policy->max_target_bpp = dsc_policy_max_target_bpp_limit;
1081 
1082 	/* apply override */
1083 	if (max_target_bpp_limit_override_x16 && policy->max_target_bpp > max_target_bpp_limit_override_x16 / 16)
1084 		policy->max_target_bpp = max_target_bpp_limit_override_x16 / 16;
1085 
1086 	/* enable DSC when not needed, default false */
1087 	if (dsc_policy_enable_dsc_when_not_needed)
1088 		policy->enable_dsc_when_not_needed = dsc_policy_enable_dsc_when_not_needed;
1089 	else
1090 		policy->enable_dsc_when_not_needed = false;
1091 }
1092 
1093 void dc_dsc_policy_set_max_target_bpp_limit(uint32_t limit)
1094 {
1095 	dsc_policy_max_target_bpp_limit = limit;
1096 }
1097 
1098 void dc_dsc_policy_set_enable_dsc_when_not_needed(bool enable)
1099 {
1100 	dsc_policy_enable_dsc_when_not_needed = enable;
1101 }
1102 
1103 void dc_dsc_policy_set_disable_dsc_stream_overhead(bool disable)
1104 {
1105 	dsc_policy_disable_dsc_stream_overhead = disable;
1106 }
1107