xref: /openbmc/linux/drivers/gpu/drm/amd/display/dc/dsc/dc_dsc.c (revision b1a792601f264df7172a728f1a83a05b6b399dfb)
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/drm_dp_helper.h>
29 #include "dc.h"
30 #include "rc_calc.h"
31 
32 /* This module's internal functions */
33 
34 /* default DSC policy target bitrate limit is 16bpp */
35 static uint32_t dsc_policy_max_target_bpp_limit = 16;
36 
37 /* default DSC policy enables DSC only when needed */
38 static bool dsc_policy_enable_dsc_when_not_needed;
39 
40 static uint32_t dc_dsc_bandwidth_in_kbps_from_timing(
41 	const struct dc_crtc_timing *timing)
42 {
43 	uint32_t bits_per_channel = 0;
44 	uint32_t kbps;
45 
46 	if (timing->flags.DSC) {
47 		kbps = (timing->pix_clk_100hz * timing->dsc_cfg.bits_per_pixel);
48 		kbps = kbps / 160 + ((kbps % 160) ? 1 : 0);
49 		return kbps;
50 	}
51 
52 	switch (timing->display_color_depth) {
53 	case COLOR_DEPTH_666:
54 		bits_per_channel = 6;
55 		break;
56 	case COLOR_DEPTH_888:
57 		bits_per_channel = 8;
58 		break;
59 	case COLOR_DEPTH_101010:
60 		bits_per_channel = 10;
61 		break;
62 	case COLOR_DEPTH_121212:
63 		bits_per_channel = 12;
64 		break;
65 	case COLOR_DEPTH_141414:
66 		bits_per_channel = 14;
67 		break;
68 	case COLOR_DEPTH_161616:
69 		bits_per_channel = 16;
70 		break;
71 	default:
72 		break;
73 	}
74 
75 	ASSERT(bits_per_channel != 0);
76 
77 	kbps = timing->pix_clk_100hz / 10;
78 	kbps *= bits_per_channel;
79 
80 	if (timing->flags.Y_ONLY != 1) {
81 		/*Only YOnly make reduce bandwidth by 1/3 compares to RGB*/
82 		kbps *= 3;
83 		if (timing->pixel_encoding == PIXEL_ENCODING_YCBCR420)
84 			kbps /= 2;
85 		else if (timing->pixel_encoding == PIXEL_ENCODING_YCBCR422)
86 			kbps = kbps * 2 / 3;
87 	}
88 
89 	return kbps;
90 
91 }
92 
93 static bool dsc_buff_block_size_from_dpcd(int dpcd_buff_block_size, int *buff_block_size)
94 {
95 
96 	switch (dpcd_buff_block_size) {
97 	case DP_DSC_RC_BUF_BLK_SIZE_1:
98 		*buff_block_size = 1024;
99 		break;
100 	case DP_DSC_RC_BUF_BLK_SIZE_4:
101 		*buff_block_size = 4 * 1024;
102 		break;
103 	case DP_DSC_RC_BUF_BLK_SIZE_16:
104 		*buff_block_size = 16 * 1024;
105 		break;
106 	case DP_DSC_RC_BUF_BLK_SIZE_64:
107 		*buff_block_size = 64 * 1024;
108 		break;
109 	default: {
110 			dm_error("%s: DPCD DSC buffer size not recognized.\n", __func__);
111 			return false;
112 		}
113 	}
114 
115 	return true;
116 }
117 
118 
119 static bool dsc_line_buff_depth_from_dpcd(int dpcd_line_buff_bit_depth, int *line_buff_bit_depth)
120 {
121 	if (0 <= dpcd_line_buff_bit_depth && dpcd_line_buff_bit_depth <= 7)
122 		*line_buff_bit_depth = dpcd_line_buff_bit_depth + 9;
123 	else if (dpcd_line_buff_bit_depth == 8)
124 		*line_buff_bit_depth = 8;
125 	else {
126 		dm_error("%s: DPCD DSC buffer depth not recognized.\n", __func__);
127 		return false;
128 	}
129 
130 	return true;
131 }
132 
133 
134 static bool dsc_throughput_from_dpcd(int dpcd_throughput, int *throughput)
135 {
136 	switch (dpcd_throughput) {
137 	case DP_DSC_THROUGHPUT_MODE_0_UNSUPPORTED:
138 		*throughput = 0;
139 		break;
140 	case DP_DSC_THROUGHPUT_MODE_0_170:
141 		*throughput = 170;
142 		break;
143 	case DP_DSC_THROUGHPUT_MODE_0_340:
144 		*throughput = 340;
145 		break;
146 	case DP_DSC_THROUGHPUT_MODE_0_400:
147 		*throughput = 400;
148 		break;
149 	case DP_DSC_THROUGHPUT_MODE_0_450:
150 		*throughput = 450;
151 		break;
152 	case DP_DSC_THROUGHPUT_MODE_0_500:
153 		*throughput = 500;
154 		break;
155 	case DP_DSC_THROUGHPUT_MODE_0_550:
156 		*throughput = 550;
157 		break;
158 	case DP_DSC_THROUGHPUT_MODE_0_600:
159 		*throughput = 600;
160 		break;
161 	case DP_DSC_THROUGHPUT_MODE_0_650:
162 		*throughput = 650;
163 		break;
164 	case DP_DSC_THROUGHPUT_MODE_0_700:
165 		*throughput = 700;
166 		break;
167 	case DP_DSC_THROUGHPUT_MODE_0_750:
168 		*throughput = 750;
169 		break;
170 	case DP_DSC_THROUGHPUT_MODE_0_800:
171 		*throughput = 800;
172 		break;
173 	case DP_DSC_THROUGHPUT_MODE_0_850:
174 		*throughput = 850;
175 		break;
176 	case DP_DSC_THROUGHPUT_MODE_0_900:
177 		*throughput = 900;
178 		break;
179 	case DP_DSC_THROUGHPUT_MODE_0_950:
180 		*throughput = 950;
181 		break;
182 	case DP_DSC_THROUGHPUT_MODE_0_1000:
183 		*throughput = 1000;
184 		break;
185 	default: {
186 			dm_error("%s: DPCD DSC throughput mode not recognized.\n", __func__);
187 			return false;
188 		}
189 	}
190 
191 	return true;
192 }
193 
194 
195 static bool dsc_bpp_increment_div_from_dpcd(uint8_t bpp_increment_dpcd, uint32_t *bpp_increment_div)
196 {
197 	// Mask bpp increment dpcd field to avoid reading other fields
198 	bpp_increment_dpcd &= 0x7;
199 
200 	switch (bpp_increment_dpcd) {
201 	case 0:
202 		*bpp_increment_div = 16;
203 		break;
204 	case 1:
205 		*bpp_increment_div = 8;
206 		break;
207 	case 2:
208 		*bpp_increment_div = 4;
209 		break;
210 	case 3:
211 		*bpp_increment_div = 2;
212 		break;
213 	case 4:
214 		*bpp_increment_div = 1;
215 		break;
216 	default: {
217 		dm_error("%s: DPCD DSC bits-per-pixel increment not recognized.\n", __func__);
218 		return false;
219 	}
220 	}
221 
222 	return true;
223 }
224 
225 static void get_dsc_enc_caps(
226 	const struct display_stream_compressor *dsc,
227 	struct dsc_enc_caps *dsc_enc_caps,
228 	int pixel_clock_100Hz)
229 {
230 	// This is a static HW query, so we can use any DSC
231 
232 	memset(dsc_enc_caps, 0, sizeof(struct dsc_enc_caps));
233 	if (dsc) {
234 		if (!dsc->ctx->dc->debug.disable_dsc)
235 			dsc->funcs->dsc_get_enc_caps(dsc_enc_caps, pixel_clock_100Hz);
236 		if (dsc->ctx->dc->debug.native422_support)
237 			dsc_enc_caps->color_formats.bits.YCBCR_NATIVE_422 = 1;
238 	}
239 }
240 
241 /* Returns 'false' if no intersection was found for at least one capablity.
242  * It also implicitly validates some sink caps against invalid value of zero.
243  */
244 static bool intersect_dsc_caps(
245 	const struct dsc_dec_dpcd_caps *dsc_sink_caps,
246 	const struct dsc_enc_caps *dsc_enc_caps,
247 	enum dc_pixel_encoding pixel_encoding,
248 	struct dsc_enc_caps *dsc_common_caps)
249 {
250 	int32_t max_slices;
251 	int32_t total_sink_throughput;
252 
253 	memset(dsc_common_caps, 0, sizeof(struct dsc_enc_caps));
254 
255 	dsc_common_caps->dsc_version = min(dsc_sink_caps->dsc_version, dsc_enc_caps->dsc_version);
256 	if (!dsc_common_caps->dsc_version)
257 		return false;
258 
259 	dsc_common_caps->slice_caps.bits.NUM_SLICES_1 = dsc_sink_caps->slice_caps1.bits.NUM_SLICES_1 && dsc_enc_caps->slice_caps.bits.NUM_SLICES_1;
260 	dsc_common_caps->slice_caps.bits.NUM_SLICES_2 = dsc_sink_caps->slice_caps1.bits.NUM_SLICES_2 && dsc_enc_caps->slice_caps.bits.NUM_SLICES_2;
261 	dsc_common_caps->slice_caps.bits.NUM_SLICES_4 = dsc_sink_caps->slice_caps1.bits.NUM_SLICES_4 && dsc_enc_caps->slice_caps.bits.NUM_SLICES_4;
262 	dsc_common_caps->slice_caps.bits.NUM_SLICES_8 = dsc_sink_caps->slice_caps1.bits.NUM_SLICES_8 && dsc_enc_caps->slice_caps.bits.NUM_SLICES_8;
263 	if (!dsc_common_caps->slice_caps.raw)
264 		return false;
265 
266 	dsc_common_caps->lb_bit_depth = min(dsc_sink_caps->lb_bit_depth, dsc_enc_caps->lb_bit_depth);
267 	if (!dsc_common_caps->lb_bit_depth)
268 		return false;
269 
270 	dsc_common_caps->is_block_pred_supported = dsc_sink_caps->is_block_pred_supported && dsc_enc_caps->is_block_pred_supported;
271 
272 	dsc_common_caps->color_formats.raw = dsc_sink_caps->color_formats.raw & dsc_enc_caps->color_formats.raw;
273 	if (!dsc_common_caps->color_formats.raw)
274 		return false;
275 
276 	dsc_common_caps->color_depth.raw = dsc_sink_caps->color_depth.raw & dsc_enc_caps->color_depth.raw;
277 	if (!dsc_common_caps->color_depth.raw)
278 		return false;
279 
280 	max_slices = 0;
281 	if (dsc_common_caps->slice_caps.bits.NUM_SLICES_1)
282 		max_slices = 1;
283 
284 	if (dsc_common_caps->slice_caps.bits.NUM_SLICES_2)
285 		max_slices = 2;
286 
287 	if (dsc_common_caps->slice_caps.bits.NUM_SLICES_4)
288 		max_slices = 4;
289 
290 	total_sink_throughput = max_slices * dsc_sink_caps->throughput_mode_0_mps;
291 	if (pixel_encoding == PIXEL_ENCODING_YCBCR422 || pixel_encoding == PIXEL_ENCODING_YCBCR420)
292 		total_sink_throughput = max_slices * dsc_sink_caps->throughput_mode_1_mps;
293 
294 	dsc_common_caps->max_total_throughput_mps = min(total_sink_throughput, dsc_enc_caps->max_total_throughput_mps);
295 
296 	dsc_common_caps->max_slice_width = min(dsc_sink_caps->max_slice_width, dsc_enc_caps->max_slice_width);
297 	if (!dsc_common_caps->max_slice_width)
298 		return false;
299 
300 	dsc_common_caps->bpp_increment_div = min(dsc_sink_caps->bpp_increment_div, dsc_enc_caps->bpp_increment_div);
301 
302 	// TODO DSC: Remove this workaround for N422 and 420 once it's fixed, or move it to get_dsc_encoder_caps()
303 	if (pixel_encoding == PIXEL_ENCODING_YCBCR422 || pixel_encoding == PIXEL_ENCODING_YCBCR420)
304 		dsc_common_caps->bpp_increment_div = min(dsc_common_caps->bpp_increment_div, (uint32_t)8);
305 
306 	return true;
307 }
308 
309 static inline uint32_t dsc_div_by_10_round_up(uint32_t value)
310 {
311 	return (value + 9) / 10;
312 }
313 
314 /* Get DSC bandwidth range based on [min_bpp, max_bpp] target bitrate range, and timing's pixel clock
315  * and uncompressed bandwidth.
316  */
317 static void get_dsc_bandwidth_range(
318 		const uint32_t min_bpp,
319 		const uint32_t max_bpp,
320 		const struct dsc_enc_caps *dsc_caps,
321 		const struct dc_crtc_timing *timing,
322 		struct dc_dsc_bw_range *range)
323 {
324 	/* native stream bandwidth */
325 	range->stream_kbps = dc_dsc_bandwidth_in_kbps_from_timing(timing);
326 
327 	/* max dsc target bpp */
328 	range->max_kbps = dsc_div_by_10_round_up(max_bpp * timing->pix_clk_100hz);
329 	range->max_target_bpp_x16 = max_bpp * 16;
330 	if (range->max_kbps > range->stream_kbps) {
331 		/* max dsc target bpp is capped to native bandwidth */
332 		range->max_kbps = range->stream_kbps;
333 		range->max_target_bpp_x16 = calc_dsc_bpp_x16(range->stream_kbps, timing->pix_clk_100hz, dsc_caps->bpp_increment_div);
334 	}
335 
336 	/* min dsc target bpp */
337 	range->min_kbps = dsc_div_by_10_round_up(min_bpp * timing->pix_clk_100hz);
338 	range->min_target_bpp_x16 = min_bpp * 16;
339 	if (range->min_kbps > range->max_kbps) {
340 		/* min dsc target bpp is capped to max dsc bandwidth*/
341 		range->min_kbps = range->max_kbps;
342 		range->min_target_bpp_x16 = range->max_target_bpp_x16;
343 	}
344 }
345 
346 
347 /* Decides if DSC should be used and calculates target bpp if it should, applying DSC policy.
348  *
349  * Returns:
350  *     - 'true' if DSC was required by policy and was successfully applied
351  *     - 'false' if DSC was not necessary (e.g. if uncompressed stream fits 'target_bandwidth_kbps'),
352  *        or if it couldn't be applied based on DSC policy.
353  */
354 static bool decide_dsc_target_bpp_x16(
355 		const struct dc_dsc_policy *policy,
356 		const struct dsc_enc_caps *dsc_common_caps,
357 		const int target_bandwidth_kbps,
358 		const struct dc_crtc_timing *timing,
359 		int *target_bpp_x16)
360 {
361 	bool should_use_dsc = false;
362 	struct dc_dsc_bw_range range;
363 
364 	memset(&range, 0, sizeof(range));
365 
366 	get_dsc_bandwidth_range(policy->min_target_bpp, policy->max_target_bpp,
367 			dsc_common_caps, timing, &range);
368 	if (!policy->enable_dsc_when_not_needed && target_bandwidth_kbps >= range.stream_kbps) {
369 		/* enough bandwidth without dsc */
370 		*target_bpp_x16 = 0;
371 		should_use_dsc = false;
372 	} else if (target_bandwidth_kbps >= range.max_kbps) {
373 		/* use max target bpp allowed */
374 		*target_bpp_x16 = range.max_target_bpp_x16;
375 		should_use_dsc = true;
376 	} else if (target_bandwidth_kbps >= range.min_kbps) {
377 		/* use target bpp that can take entire target bandwidth */
378 		*target_bpp_x16 = calc_dsc_bpp_x16(target_bandwidth_kbps, timing->pix_clk_100hz, dsc_common_caps->bpp_increment_div);
379 		should_use_dsc = true;
380 	} else {
381 		/* not enough bandwidth to fulfill minimum requirement */
382 		*target_bpp_x16 = 0;
383 		should_use_dsc = false;
384 	}
385 
386 	return should_use_dsc;
387 }
388 
389 #define MIN_AVAILABLE_SLICES_SIZE  4
390 
391 static int get_available_dsc_slices(union dsc_enc_slice_caps slice_caps, int *available_slices)
392 {
393 	int idx = 0;
394 
395 	memset(available_slices, -1, MIN_AVAILABLE_SLICES_SIZE);
396 
397 	if (slice_caps.bits.NUM_SLICES_1)
398 		available_slices[idx++] = 1;
399 
400 	if (slice_caps.bits.NUM_SLICES_2)
401 		available_slices[idx++] = 2;
402 
403 	if (slice_caps.bits.NUM_SLICES_4)
404 		available_slices[idx++] = 4;
405 
406 	if (slice_caps.bits.NUM_SLICES_8)
407 		available_slices[idx++] = 8;
408 
409 	return idx;
410 }
411 
412 
413 static int get_max_dsc_slices(union dsc_enc_slice_caps slice_caps)
414 {
415 	int max_slices = 0;
416 	int available_slices[MIN_AVAILABLE_SLICES_SIZE];
417 	int end_idx = get_available_dsc_slices(slice_caps, &available_slices[0]);
418 
419 	if (end_idx > 0)
420 		max_slices = available_slices[end_idx - 1];
421 
422 	return max_slices;
423 }
424 
425 
426 // Increment sice number in available sice numbers stops if possible, or just increment if not
427 static int inc_num_slices(union dsc_enc_slice_caps slice_caps, int num_slices)
428 {
429 	// Get next bigger num slices available in common caps
430 	int available_slices[MIN_AVAILABLE_SLICES_SIZE];
431 	int end_idx;
432 	int i;
433 	int new_num_slices = num_slices;
434 
435 	end_idx = get_available_dsc_slices(slice_caps, &available_slices[0]);
436 	if (end_idx == 0) {
437 		// No available slices found
438 		new_num_slices++;
439 		return new_num_slices;
440 	}
441 
442 	// Numbers of slices found - get the next bigger number
443 	for (i = 0; i < end_idx; i++) {
444 		if (new_num_slices < available_slices[i]) {
445 			new_num_slices = available_slices[i];
446 			break;
447 		}
448 	}
449 
450 	if (new_num_slices == num_slices) // No biger number of slices found
451 		new_num_slices++;
452 
453 	return new_num_slices;
454 }
455 
456 
457 // Decrement sice number in available sice numbers stops if possible, or just decrement if not. Stop at zero.
458 static int dec_num_slices(union dsc_enc_slice_caps slice_caps, int num_slices)
459 {
460 	// Get next bigger num slices available in common caps
461 	int available_slices[MIN_AVAILABLE_SLICES_SIZE];
462 	int end_idx;
463 	int i;
464 	int new_num_slices = num_slices;
465 
466 	end_idx = get_available_dsc_slices(slice_caps, &available_slices[0]);
467 	if (end_idx == 0 && new_num_slices > 0) {
468 		// No numbers of slices found
469 		new_num_slices++;
470 		return new_num_slices;
471 	}
472 
473 	// Numbers of slices found - get the next smaller number
474 	for (i = end_idx - 1; i >= 0; i--) {
475 		if (new_num_slices > available_slices[i]) {
476 			new_num_slices = available_slices[i];
477 			break;
478 		}
479 	}
480 
481 	if (new_num_slices == num_slices) {
482 		// No smaller number of slices found
483 		new_num_slices--;
484 		if (new_num_slices < 0)
485 			new_num_slices = 0;
486 	}
487 
488 	return new_num_slices;
489 }
490 
491 
492 // Choose next bigger number of slices if the requested number of slices is not available
493 static int fit_num_slices_up(union dsc_enc_slice_caps slice_caps, int num_slices)
494 {
495 	// Get next bigger num slices available in common caps
496 	int available_slices[MIN_AVAILABLE_SLICES_SIZE];
497 	int end_idx;
498 	int i;
499 	int new_num_slices = num_slices;
500 
501 	end_idx = get_available_dsc_slices(slice_caps, &available_slices[0]);
502 	if (end_idx == 0) {
503 		// No available slices found
504 		new_num_slices++;
505 		return new_num_slices;
506 	}
507 
508 	// Numbers of slices found - get the equal or next bigger number
509 	for (i = 0; i < end_idx; i++) {
510 		if (new_num_slices <= available_slices[i]) {
511 			new_num_slices = available_slices[i];
512 			break;
513 		}
514 	}
515 
516 	return new_num_slices;
517 }
518 
519 
520 /* Attempts to set DSC configuration for the stream, applying DSC policy.
521  * Returns 'true' if successful or 'false' if not.
522  *
523  * Parameters:
524  *
525  * dsc_sink_caps       - DSC sink decoder capabilities (from DPCD)
526  *
527  * dsc_enc_caps        - DSC encoder capabilities
528  *
529  * target_bandwidth_kbps  - Target bandwidth to fit the stream into.
530  *                          If 0, do not calculate target bpp.
531  *
532  * timing              - The stream timing to fit into 'target_bandwidth_kbps' or apply
533  *                       maximum compression to, if 'target_badwidth == 0'
534  *
535  * dsc_cfg             - DSC configuration to use if it was possible to come up with
536  *                       one for the given inputs.
537  *                       The target bitrate after DSC can be calculated by multiplying
538  *                       dsc_cfg.bits_per_pixel (in U6.4 format) by pixel rate, e.g.
539  *
540  *                       dsc_stream_bitrate_kbps = (int)ceil(timing->pix_clk_khz * dsc_cfg.bits_per_pixel / 16.0);
541  */
542 static bool setup_dsc_config(
543 		const struct dsc_dec_dpcd_caps *dsc_sink_caps,
544 		const struct dsc_enc_caps *dsc_enc_caps,
545 		int target_bandwidth_kbps,
546 		const struct dc_crtc_timing *timing,
547 		int min_slice_height_override,
548 		int max_dsc_target_bpp_limit_override,
549 		struct dc_dsc_config *dsc_cfg)
550 {
551 	struct dsc_enc_caps dsc_common_caps;
552 	int max_slices_h;
553 	int min_slices_h;
554 	int num_slices_h;
555 	int pic_width;
556 	int slice_width;
557 	int target_bpp;
558 	int sink_per_slice_throughput_mps;
559 	int branch_max_throughput_mps = 0;
560 	bool is_dsc_possible = false;
561 	int pic_height;
562 	int slice_height;
563 	struct dc_dsc_policy policy;
564 
565 	memset(dsc_cfg, 0, sizeof(struct dc_dsc_config));
566 
567 	dc_dsc_get_policy_for_timing(timing, max_dsc_target_bpp_limit_override, &policy);
568 	pic_width = timing->h_addressable + timing->h_border_left + timing->h_border_right;
569 	pic_height = timing->v_addressable + timing->v_border_top + timing->v_border_bottom;
570 
571 	if (!dsc_sink_caps->is_dsc_supported)
572 		goto done;
573 
574 	if (dsc_sink_caps->branch_max_line_width && dsc_sink_caps->branch_max_line_width < pic_width)
575 		goto done;
576 
577 	// Intersect decoder with encoder DSC caps and validate DSC settings
578 	is_dsc_possible = intersect_dsc_caps(dsc_sink_caps, dsc_enc_caps, timing->pixel_encoding, &dsc_common_caps);
579 	if (!is_dsc_possible)
580 		goto done;
581 
582 	if (target_bandwidth_kbps > 0) {
583 		is_dsc_possible = decide_dsc_target_bpp_x16(
584 				&policy,
585 				&dsc_common_caps,
586 				target_bandwidth_kbps,
587 				timing,
588 				&target_bpp);
589 		dsc_cfg->bits_per_pixel = target_bpp;
590 	}
591 	if (!is_dsc_possible)
592 		goto done;
593 
594 	sink_per_slice_throughput_mps = 0;
595 
596 	// Validate available DSC settings against the mode timing
597 
598 	// Validate color format (and pick up the throughput values)
599 	dsc_cfg->ycbcr422_simple = false;
600 	switch (timing->pixel_encoding)	{
601 	case PIXEL_ENCODING_RGB:
602 		is_dsc_possible = (bool)dsc_common_caps.color_formats.bits.RGB;
603 		sink_per_slice_throughput_mps = dsc_sink_caps->throughput_mode_0_mps;
604 		branch_max_throughput_mps = dsc_sink_caps->branch_overall_throughput_0_mps;
605 		break;
606 	case PIXEL_ENCODING_YCBCR444:
607 		is_dsc_possible = (bool)dsc_common_caps.color_formats.bits.YCBCR_444;
608 		sink_per_slice_throughput_mps = dsc_sink_caps->throughput_mode_0_mps;
609 		branch_max_throughput_mps = dsc_sink_caps->branch_overall_throughput_0_mps;
610 		break;
611 	case PIXEL_ENCODING_YCBCR422:
612 		is_dsc_possible = (bool)dsc_common_caps.color_formats.bits.YCBCR_NATIVE_422;
613 		sink_per_slice_throughput_mps = dsc_sink_caps->throughput_mode_1_mps;
614 		branch_max_throughput_mps = dsc_sink_caps->branch_overall_throughput_1_mps;
615 		if (!is_dsc_possible) {
616 			is_dsc_possible = (bool)dsc_common_caps.color_formats.bits.YCBCR_SIMPLE_422;
617 			dsc_cfg->ycbcr422_simple = is_dsc_possible;
618 			sink_per_slice_throughput_mps = dsc_sink_caps->throughput_mode_0_mps;
619 		}
620 		break;
621 	case PIXEL_ENCODING_YCBCR420:
622 		is_dsc_possible = (bool)dsc_common_caps.color_formats.bits.YCBCR_NATIVE_420;
623 		sink_per_slice_throughput_mps = dsc_sink_caps->throughput_mode_1_mps;
624 		branch_max_throughput_mps = dsc_sink_caps->branch_overall_throughput_1_mps;
625 		break;
626 	default:
627 		is_dsc_possible = false;
628 	}
629 
630 	// Validate branch's maximum throughput
631 	if (branch_max_throughput_mps && dsc_div_by_10_round_up(timing->pix_clk_100hz) > branch_max_throughput_mps * 1000)
632 		is_dsc_possible = false;
633 
634 	if (!is_dsc_possible)
635 		goto done;
636 
637 	// Color depth
638 	switch (timing->display_color_depth) {
639 	case COLOR_DEPTH_888:
640 		is_dsc_possible = (bool)dsc_common_caps.color_depth.bits.COLOR_DEPTH_8_BPC;
641 		break;
642 	case COLOR_DEPTH_101010:
643 		is_dsc_possible = (bool)dsc_common_caps.color_depth.bits.COLOR_DEPTH_10_BPC;
644 		break;
645 	case COLOR_DEPTH_121212:
646 		is_dsc_possible = (bool)dsc_common_caps.color_depth.bits.COLOR_DEPTH_12_BPC;
647 		break;
648 	default:
649 		is_dsc_possible = false;
650 	}
651 
652 	if (!is_dsc_possible)
653 		goto done;
654 
655 	// Slice width (i.e. number of slices per line)
656 	max_slices_h = get_max_dsc_slices(dsc_common_caps.slice_caps);
657 
658 	while (max_slices_h > 0) {
659 		if (pic_width % max_slices_h == 0)
660 			break;
661 
662 		max_slices_h = dec_num_slices(dsc_common_caps.slice_caps, max_slices_h);
663 	}
664 
665 	is_dsc_possible = (dsc_common_caps.max_slice_width > 0);
666 	if (!is_dsc_possible)
667 		goto done;
668 
669 	min_slices_h = pic_width / dsc_common_caps.max_slice_width;
670 	if (pic_width % dsc_common_caps.max_slice_width)
671 		min_slices_h++;
672 
673 	min_slices_h = fit_num_slices_up(dsc_common_caps.slice_caps, min_slices_h);
674 
675 	while (min_slices_h <= max_slices_h) {
676 		int pix_clk_per_slice_khz = dsc_div_by_10_round_up(timing->pix_clk_100hz) / min_slices_h;
677 		if (pix_clk_per_slice_khz <= sink_per_slice_throughput_mps * 1000)
678 			break;
679 
680 		min_slices_h = inc_num_slices(dsc_common_caps.slice_caps, min_slices_h);
681 	}
682 
683 	if (pic_width % min_slices_h != 0)
684 		min_slices_h = 0; // DSC TODO: Maybe try increasing the number of slices first?
685 
686 	is_dsc_possible = (min_slices_h <= max_slices_h);
687 	if (!is_dsc_possible)
688 		goto done;
689 
690 	if (policy.use_min_slices_h) {
691 		if (min_slices_h > 0)
692 			num_slices_h = min_slices_h;
693 		else if (max_slices_h > 0) { // Fall back to max slices if min slices is not working out
694 			if (policy.max_slices_h)
695 				num_slices_h = min(policy.max_slices_h, max_slices_h);
696 			else
697 				num_slices_h = max_slices_h;
698 		} else
699 			is_dsc_possible = false;
700 	} else {
701 		if (max_slices_h > 0) {
702 			if (policy.max_slices_h)
703 				num_slices_h = min(policy.max_slices_h, max_slices_h);
704 			else
705 				num_slices_h = max_slices_h;
706 		} else if (min_slices_h > 0) // Fall back to min slices if max slices is not possible
707 			num_slices_h = min_slices_h;
708 		else
709 			is_dsc_possible = false;
710 	}
711 
712 	if (!is_dsc_possible)
713 		goto done;
714 
715 	dsc_cfg->num_slices_h = num_slices_h;
716 	slice_width = pic_width / num_slices_h;
717 
718 	is_dsc_possible = slice_width <= dsc_common_caps.max_slice_width;
719 	if (!is_dsc_possible)
720 		goto done;
721 
722 	// Slice height (i.e. number of slices per column): start with policy and pick the first one that height is divisible by.
723 	// For 4:2:0 make sure the slice height is divisible by 2 as well.
724 	if (min_slice_height_override == 0)
725 		slice_height = min(policy.min_slice_height, pic_height);
726 	else
727 		slice_height = min(min_slice_height_override, pic_height);
728 
729 	while (slice_height < pic_height && (pic_height % slice_height != 0 ||
730 		(timing->pixel_encoding == PIXEL_ENCODING_YCBCR420 && slice_height % 2 != 0)))
731 		slice_height++;
732 
733 	if (timing->pixel_encoding == PIXEL_ENCODING_YCBCR420) // For the case when pic_height < dsc_policy.min_sice_height
734 		is_dsc_possible = (slice_height % 2 == 0);
735 
736 	if (!is_dsc_possible)
737 		goto done;
738 
739 	dsc_cfg->num_slices_v = pic_height/slice_height;
740 
741 	// Final decission: can we do DSC or not?
742 	if (is_dsc_possible) {
743 		// Fill out the rest of DSC settings
744 		dsc_cfg->block_pred_enable = dsc_common_caps.is_block_pred_supported;
745 		dsc_cfg->linebuf_depth = dsc_common_caps.lb_bit_depth;
746 		dsc_cfg->version_minor = (dsc_common_caps.dsc_version & 0xf0) >> 4;
747 	}
748 
749 done:
750 	if (!is_dsc_possible)
751 		memset(dsc_cfg, 0, sizeof(struct dc_dsc_config));
752 
753 	return is_dsc_possible;
754 }
755 
756 bool dc_dsc_parse_dsc_dpcd(const struct dc *dc, const uint8_t *dpcd_dsc_basic_data, const uint8_t *dpcd_dsc_branch_decoder_caps, struct dsc_dec_dpcd_caps *dsc_sink_caps)
757 {
758 	if (!dpcd_dsc_basic_data)
759 		return false;
760 
761 	dsc_sink_caps->is_dsc_supported = (dpcd_dsc_basic_data[DP_DSC_SUPPORT - DP_DSC_SUPPORT] & DP_DSC_DECOMPRESSION_IS_SUPPORTED) != 0;
762 	if (!dsc_sink_caps->is_dsc_supported)
763 		return false;
764 
765 	dsc_sink_caps->dsc_version = dpcd_dsc_basic_data[DP_DSC_REV - DP_DSC_SUPPORT];
766 
767 	{
768 		int buff_block_size;
769 		int buff_size;
770 
771 		if (!dsc_buff_block_size_from_dpcd(dpcd_dsc_basic_data[DP_DSC_RC_BUF_BLK_SIZE - DP_DSC_SUPPORT], &buff_block_size))
772 			return false;
773 
774 		buff_size = dpcd_dsc_basic_data[DP_DSC_RC_BUF_SIZE - DP_DSC_SUPPORT] + 1;
775 		dsc_sink_caps->rc_buffer_size = buff_size * buff_block_size;
776 	}
777 
778 	dsc_sink_caps->slice_caps1.raw = dpcd_dsc_basic_data[DP_DSC_SLICE_CAP_1 - DP_DSC_SUPPORT];
779 	if (!dsc_line_buff_depth_from_dpcd(dpcd_dsc_basic_data[DP_DSC_LINE_BUF_BIT_DEPTH - DP_DSC_SUPPORT], &dsc_sink_caps->lb_bit_depth))
780 		return false;
781 
782 	dsc_sink_caps->is_block_pred_supported =
783 		(dpcd_dsc_basic_data[DP_DSC_BLK_PREDICTION_SUPPORT - DP_DSC_SUPPORT] & DP_DSC_BLK_PREDICTION_IS_SUPPORTED) != 0;
784 
785 	dsc_sink_caps->edp_max_bits_per_pixel =
786 		dpcd_dsc_basic_data[DP_DSC_MAX_BITS_PER_PIXEL_LOW - DP_DSC_SUPPORT] |
787 		dpcd_dsc_basic_data[DP_DSC_MAX_BITS_PER_PIXEL_HI - DP_DSC_SUPPORT] << 8;
788 
789 	dsc_sink_caps->color_formats.raw = dpcd_dsc_basic_data[DP_DSC_DEC_COLOR_FORMAT_CAP - DP_DSC_SUPPORT];
790 	dsc_sink_caps->color_depth.raw = dpcd_dsc_basic_data[DP_DSC_DEC_COLOR_DEPTH_CAP - DP_DSC_SUPPORT];
791 
792 	{
793 		int dpcd_throughput = dpcd_dsc_basic_data[DP_DSC_PEAK_THROUGHPUT - DP_DSC_SUPPORT];
794 
795 		if (!dsc_throughput_from_dpcd(dpcd_throughput & DP_DSC_THROUGHPUT_MODE_0_MASK, &dsc_sink_caps->throughput_mode_0_mps))
796 			return false;
797 
798 		dpcd_throughput = (dpcd_throughput & DP_DSC_THROUGHPUT_MODE_1_MASK) >> DP_DSC_THROUGHPUT_MODE_1_SHIFT;
799 		if (!dsc_throughput_from_dpcd(dpcd_throughput, &dsc_sink_caps->throughput_mode_1_mps))
800 			return false;
801 	}
802 
803 	dsc_sink_caps->max_slice_width = dpcd_dsc_basic_data[DP_DSC_MAX_SLICE_WIDTH - DP_DSC_SUPPORT] * 320;
804 	dsc_sink_caps->slice_caps2.raw = dpcd_dsc_basic_data[DP_DSC_SLICE_CAP_2 - DP_DSC_SUPPORT];
805 
806 	if (!dsc_bpp_increment_div_from_dpcd(dpcd_dsc_basic_data[DP_DSC_BITS_PER_PIXEL_INC - DP_DSC_SUPPORT], &dsc_sink_caps->bpp_increment_div))
807 		return false;
808 
809 	if (dc->debug.dsc_bpp_increment_div) {
810 		/* dsc_bpp_increment_div should onl be 1, 2, 4, 8 or 16, but rather than rejecting invalid values,
811 		 * we'll accept all and get it into range. This also makes the above check against 0 redundant,
812 		 * but that one stresses out the override will be only used if it's not 0.
813 		 */
814 		if (dc->debug.dsc_bpp_increment_div >= 1)
815 			dsc_sink_caps->bpp_increment_div = 1;
816 		if (dc->debug.dsc_bpp_increment_div >= 2)
817 			dsc_sink_caps->bpp_increment_div = 2;
818 		if (dc->debug.dsc_bpp_increment_div >= 4)
819 			dsc_sink_caps->bpp_increment_div = 4;
820 		if (dc->debug.dsc_bpp_increment_div >= 8)
821 			dsc_sink_caps->bpp_increment_div = 8;
822 		if (dc->debug.dsc_bpp_increment_div >= 16)
823 			dsc_sink_caps->bpp_increment_div = 16;
824 	}
825 
826 	/* Extended caps */
827 	if (dpcd_dsc_branch_decoder_caps == NULL) { // branch decoder DPCD DSC data can be null for non branch device
828 		dsc_sink_caps->branch_overall_throughput_0_mps = 0;
829 		dsc_sink_caps->branch_overall_throughput_1_mps = 0;
830 		dsc_sink_caps->branch_max_line_width = 0;
831 		return true;
832 	}
833 
834 	dsc_sink_caps->branch_overall_throughput_0_mps = dpcd_dsc_branch_decoder_caps[DP_DSC_BRANCH_OVERALL_THROUGHPUT_0 - DP_DSC_BRANCH_OVERALL_THROUGHPUT_0];
835 	if (dsc_sink_caps->branch_overall_throughput_0_mps == 0)
836 		dsc_sink_caps->branch_overall_throughput_0_mps = 0;
837 	else if (dsc_sink_caps->branch_overall_throughput_0_mps == 1)
838 		dsc_sink_caps->branch_overall_throughput_0_mps = 680;
839 	else {
840 		dsc_sink_caps->branch_overall_throughput_0_mps *= 50;
841 		dsc_sink_caps->branch_overall_throughput_0_mps += 600;
842 	}
843 
844 	dsc_sink_caps->branch_overall_throughput_1_mps = dpcd_dsc_branch_decoder_caps[DP_DSC_BRANCH_OVERALL_THROUGHPUT_1 - DP_DSC_BRANCH_OVERALL_THROUGHPUT_0];
845 	if (dsc_sink_caps->branch_overall_throughput_1_mps == 0)
846 		dsc_sink_caps->branch_overall_throughput_1_mps = 0;
847 	else if (dsc_sink_caps->branch_overall_throughput_1_mps == 1)
848 		dsc_sink_caps->branch_overall_throughput_1_mps = 680;
849 	else {
850 		dsc_sink_caps->branch_overall_throughput_1_mps *= 50;
851 		dsc_sink_caps->branch_overall_throughput_1_mps += 600;
852 	}
853 
854 	dsc_sink_caps->branch_max_line_width = dpcd_dsc_branch_decoder_caps[DP_DSC_BRANCH_MAX_LINE_WIDTH - DP_DSC_BRANCH_OVERALL_THROUGHPUT_0] * 320;
855 	ASSERT(dsc_sink_caps->branch_max_line_width == 0 || dsc_sink_caps->branch_max_line_width >= 5120);
856 
857 	return true;
858 }
859 
860 
861 /* If DSC is possbile, get DSC bandwidth range based on [min_bpp, max_bpp] target bitrate range and
862  * timing's pixel clock and uncompressed bandwidth.
863  * If DSC is not possible, leave '*range' untouched.
864  */
865 bool dc_dsc_compute_bandwidth_range(
866 		const struct display_stream_compressor *dsc,
867 		uint32_t dsc_min_slice_height_override,
868 		uint32_t min_bpp,
869 		uint32_t max_bpp,
870 		const struct dsc_dec_dpcd_caps *dsc_sink_caps,
871 		const struct dc_crtc_timing *timing,
872 		struct dc_dsc_bw_range *range)
873 {
874 	bool is_dsc_possible = false;
875 	struct dsc_enc_caps dsc_enc_caps;
876 	struct dsc_enc_caps dsc_common_caps;
877 	struct dc_dsc_config config;
878 
879 	get_dsc_enc_caps(dsc, &dsc_enc_caps, timing->pix_clk_100hz);
880 
881 	is_dsc_possible = intersect_dsc_caps(dsc_sink_caps, &dsc_enc_caps,
882 			timing->pixel_encoding, &dsc_common_caps);
883 
884 	if (is_dsc_possible)
885 		is_dsc_possible = setup_dsc_config(dsc_sink_caps, &dsc_enc_caps, 0, timing,
886 				dsc_min_slice_height_override, max_bpp, &config);
887 
888 	if (is_dsc_possible)
889 		get_dsc_bandwidth_range(min_bpp, max_bpp, &dsc_common_caps, timing, range);
890 
891 	return is_dsc_possible;
892 }
893 
894 bool dc_dsc_compute_config(
895 		const struct display_stream_compressor *dsc,
896 		const struct dsc_dec_dpcd_caps *dsc_sink_caps,
897 		uint32_t dsc_min_slice_height_override,
898 		uint32_t max_target_bpp_limit_override,
899 		uint32_t target_bandwidth_kbps,
900 		const struct dc_crtc_timing *timing,
901 		struct dc_dsc_config *dsc_cfg)
902 {
903 	bool is_dsc_possible = false;
904 	struct dsc_enc_caps dsc_enc_caps;
905 
906 	get_dsc_enc_caps(dsc, &dsc_enc_caps, timing->pix_clk_100hz);
907 	is_dsc_possible = setup_dsc_config(dsc_sink_caps,
908 			&dsc_enc_caps,
909 			target_bandwidth_kbps,
910 			timing, dsc_min_slice_height_override,
911 			max_target_bpp_limit_override, dsc_cfg);
912 	return is_dsc_possible;
913 }
914 
915 void dc_dsc_get_policy_for_timing(const struct dc_crtc_timing *timing, uint32_t max_target_bpp_limit_override, struct dc_dsc_policy *policy)
916 {
917 	uint32_t bpc = 0;
918 
919 	policy->min_target_bpp = 0;
920 	policy->max_target_bpp = 0;
921 
922 	/* DSC Policy: Use minimum number of slices that fits the pixel clock */
923 	policy->use_min_slices_h = true;
924 
925 	/* DSC Policy: Use max available slices
926 	 * (in our case 4 for or 8, depending on the mode)
927 	 */
928 	policy->max_slices_h = 0;
929 
930 	/* DSC Policy: Use slice height recommended
931 	 * by VESA DSC Spreadsheet user guide
932 	 */
933 	policy->min_slice_height = 108;
934 
935 	/* DSC Policy: follow DP specs with an internal upper limit to 16 bpp
936 	 * for better interoperability
937 	 */
938 	switch (timing->display_color_depth) {
939 	case COLOR_DEPTH_888:
940 		bpc = 8;
941 		break;
942 	case COLOR_DEPTH_101010:
943 		bpc = 10;
944 		break;
945 	case COLOR_DEPTH_121212:
946 		bpc = 12;
947 		break;
948 	default:
949 		return;
950 	}
951 	switch (timing->pixel_encoding) {
952 	case PIXEL_ENCODING_RGB:
953 	case PIXEL_ENCODING_YCBCR444:
954 	case PIXEL_ENCODING_YCBCR422: /* assume no YCbCr422 native support */
955 		/* DP specs limits to 8 */
956 		policy->min_target_bpp = 8;
957 		/* DP specs limits to 3 x bpc */
958 		policy->max_target_bpp = 3 * bpc;
959 		break;
960 	case PIXEL_ENCODING_YCBCR420:
961 		/* DP specs limits to 6 */
962 		policy->min_target_bpp = 6;
963 		/* DP specs limits to 1.5 x bpc assume bpc is an even number */
964 		policy->max_target_bpp = bpc * 3 / 2;
965 		break;
966 	default:
967 		return;
968 	}
969 
970 	/* internal upper limit, default 16 bpp */
971 	if (policy->max_target_bpp > dsc_policy_max_target_bpp_limit)
972 		policy->max_target_bpp = dsc_policy_max_target_bpp_limit;
973 
974 	/* apply override */
975 	if (max_target_bpp_limit_override && policy->max_target_bpp > max_target_bpp_limit_override)
976 		policy->max_target_bpp = max_target_bpp_limit_override;
977 
978 	/* enable DSC when not needed, default false */
979 	if (dsc_policy_enable_dsc_when_not_needed)
980 		policy->enable_dsc_when_not_needed = dsc_policy_enable_dsc_when_not_needed;
981 	else
982 		policy->enable_dsc_when_not_needed = false;
983 }
984 
985 void dc_dsc_policy_set_max_target_bpp_limit(uint32_t limit)
986 {
987 	dsc_policy_max_target_bpp_limit = limit;
988 }
989 
990 void dc_dsc_policy_set_enable_dsc_when_not_needed(bool enable)
991 {
992 	dsc_policy_enable_dsc_when_not_needed = enable;
993 }
994