1 /*
2  * Copyright 2016 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  * Authors: AMD
23  *
24  */
25 
26 #include <linux/slab.h>
27 
28 #include "dm_services.h"
29 #include "dc.h"
30 #include "mod_freesync.h"
31 #include "core_types.h"
32 
33 #define MOD_FREESYNC_MAX_CONCURRENT_STREAMS  32
34 
35 #define MIN_REFRESH_RANGE_IN_US 10000000
36 /* Refresh rate ramp at a fixed rate of 65 Hz/second */
37 #define STATIC_SCREEN_RAMP_DELTA_REFRESH_RATE_PER_FRAME ((1000 / 60) * 65)
38 /* Number of elements in the render times cache array */
39 #define RENDER_TIMES_MAX_COUNT 10
40 /* Threshold to exit/exit BTR (to avoid frequent enter-exits at the lower limit) */
41 #define BTR_MAX_MARGIN 2500
42 /* Threshold to change BTR multiplier (to avoid frequent changes) */
43 #define BTR_DRIFT_MARGIN 2000
44 /*Threshold to exit fixed refresh rate*/
45 #define FIXED_REFRESH_EXIT_MARGIN_IN_HZ 4
46 /* Number of consecutive frames to check before entering/exiting fixed refresh*/
47 #define FIXED_REFRESH_ENTER_FRAME_COUNT 5
48 #define FIXED_REFRESH_EXIT_FRAME_COUNT 5
49 
50 struct core_freesync {
51 	struct mod_freesync public;
52 	struct dc *dc;
53 };
54 
55 #define MOD_FREESYNC_TO_CORE(mod_freesync)\
56 		container_of(mod_freesync, struct core_freesync, public)
57 
58 struct mod_freesync *mod_freesync_create(struct dc *dc)
59 {
60 	struct core_freesync *core_freesync =
61 			kzalloc(sizeof(struct core_freesync), GFP_KERNEL);
62 
63 	if (core_freesync == NULL)
64 		goto fail_alloc_context;
65 
66 	if (dc == NULL)
67 		goto fail_construct;
68 
69 	core_freesync->dc = dc;
70 	return &core_freesync->public;
71 
72 fail_construct:
73 	kfree(core_freesync);
74 
75 fail_alloc_context:
76 	return NULL;
77 }
78 
79 void mod_freesync_destroy(struct mod_freesync *mod_freesync)
80 {
81 	struct core_freesync *core_freesync = NULL;
82 	if (mod_freesync == NULL)
83 		return;
84 	core_freesync = MOD_FREESYNC_TO_CORE(mod_freesync);
85 	kfree(core_freesync);
86 }
87 
88 #if 0 /* unused currently */
89 static unsigned int calc_refresh_in_uhz_from_duration(
90 		unsigned int duration_in_ns)
91 {
92 	unsigned int refresh_in_uhz =
93 			((unsigned int)(div64_u64((1000000000ULL * 1000000),
94 					duration_in_ns)));
95 	return refresh_in_uhz;
96 }
97 #endif
98 
99 static unsigned int calc_duration_in_us_from_refresh_in_uhz(
100 		unsigned int refresh_in_uhz)
101 {
102 	unsigned int duration_in_us =
103 			((unsigned int)(div64_u64((1000000000ULL * 1000),
104 					refresh_in_uhz)));
105 	return duration_in_us;
106 }
107 
108 static unsigned int calc_duration_in_us_from_v_total(
109 		const struct dc_stream_state *stream,
110 		const struct mod_vrr_params *in_vrr,
111 		unsigned int v_total)
112 {
113 	unsigned int duration_in_us =
114 			(unsigned int)(div64_u64(((unsigned long long)(v_total)
115 				* 10000) * stream->timing.h_total,
116 					stream->timing.pix_clk_100hz));
117 
118 	return duration_in_us;
119 }
120 
121 static unsigned int calc_v_total_from_refresh(
122 		const struct dc_stream_state *stream,
123 		unsigned int refresh_in_uhz)
124 {
125 	unsigned int v_total;
126 	unsigned int frame_duration_in_ns;
127 
128 	frame_duration_in_ns =
129 			((unsigned int)(div64_u64((1000000000ULL * 1000000),
130 					refresh_in_uhz)));
131 
132 	v_total = div64_u64(div64_u64(((unsigned long long)(
133 			frame_duration_in_ns) * (stream->timing.pix_clk_100hz / 10)),
134 			stream->timing.h_total), 1000000);
135 
136 	/* v_total cannot be less than nominal */
137 	if (v_total < stream->timing.v_total) {
138 		ASSERT(v_total < stream->timing.v_total);
139 		v_total = stream->timing.v_total;
140 	}
141 
142 	return v_total;
143 }
144 
145 static unsigned int calc_v_total_from_duration(
146 		const struct dc_stream_state *stream,
147 		const struct mod_vrr_params *vrr,
148 		unsigned int duration_in_us)
149 {
150 	unsigned int v_total = 0;
151 
152 	if (duration_in_us < vrr->min_duration_in_us)
153 		duration_in_us = vrr->min_duration_in_us;
154 
155 	if (duration_in_us > vrr->max_duration_in_us)
156 		duration_in_us = vrr->max_duration_in_us;
157 
158 	v_total = div64_u64(div64_u64(((unsigned long long)(
159 				duration_in_us) * (stream->timing.pix_clk_100hz / 10)),
160 				stream->timing.h_total), 1000);
161 
162 	/* v_total cannot be less than nominal */
163 	if (v_total < stream->timing.v_total) {
164 		ASSERT(v_total < stream->timing.v_total);
165 		v_total = stream->timing.v_total;
166 	}
167 
168 	return v_total;
169 }
170 
171 static void update_v_total_for_static_ramp(
172 		struct core_freesync *core_freesync,
173 		const struct dc_stream_state *stream,
174 		struct mod_vrr_params *in_out_vrr)
175 {
176 	unsigned int v_total = 0;
177 	unsigned int current_duration_in_us =
178 			calc_duration_in_us_from_v_total(
179 				stream, in_out_vrr,
180 				in_out_vrr->adjust.v_total_max);
181 	unsigned int target_duration_in_us =
182 			calc_duration_in_us_from_refresh_in_uhz(
183 				in_out_vrr->fixed.target_refresh_in_uhz);
184 	bool ramp_direction_is_up = (current_duration_in_us >
185 				target_duration_in_us) ? true : false;
186 
187 	/* Calc ratio between new and current frame duration with 3 digit */
188 	unsigned int frame_duration_ratio = div64_u64(1000000,
189 		(1000 +  div64_u64(((unsigned long long)(
190 		STATIC_SCREEN_RAMP_DELTA_REFRESH_RATE_PER_FRAME) *
191 		current_duration_in_us),
192 		1000000)));
193 
194 	/* Calculate delta between new and current frame duration in us */
195 	unsigned int frame_duration_delta = div64_u64(((unsigned long long)(
196 		current_duration_in_us) *
197 		(1000 - frame_duration_ratio)), 1000);
198 
199 	/* Adjust frame duration delta based on ratio between current and
200 	 * standard frame duration (frame duration at 60 Hz refresh rate).
201 	 */
202 	unsigned int ramp_rate_interpolated = div64_u64(((unsigned long long)(
203 		frame_duration_delta) * current_duration_in_us), 16666);
204 
205 	/* Going to a higher refresh rate (lower frame duration) */
206 	if (ramp_direction_is_up) {
207 		/* reduce frame duration */
208 		current_duration_in_us -= ramp_rate_interpolated;
209 
210 		/* adjust for frame duration below min */
211 		if (current_duration_in_us <= target_duration_in_us) {
212 			in_out_vrr->fixed.ramping_active = false;
213 			in_out_vrr->fixed.ramping_done = true;
214 			current_duration_in_us =
215 				calc_duration_in_us_from_refresh_in_uhz(
216 				in_out_vrr->fixed.target_refresh_in_uhz);
217 		}
218 	/* Going to a lower refresh rate (larger frame duration) */
219 	} else {
220 		/* increase frame duration */
221 		current_duration_in_us += ramp_rate_interpolated;
222 
223 		/* adjust for frame duration above max */
224 		if (current_duration_in_us >= target_duration_in_us) {
225 			in_out_vrr->fixed.ramping_active = false;
226 			in_out_vrr->fixed.ramping_done = true;
227 			current_duration_in_us =
228 				calc_duration_in_us_from_refresh_in_uhz(
229 				in_out_vrr->fixed.target_refresh_in_uhz);
230 		}
231 	}
232 
233 	v_total = div64_u64(div64_u64(((unsigned long long)(
234 			current_duration_in_us) * (stream->timing.pix_clk_100hz / 10)),
235 				stream->timing.h_total), 1000);
236 
237 	/* v_total cannot be less than nominal */
238 	if (v_total < stream->timing.v_total)
239 		v_total = stream->timing.v_total;
240 
241 	in_out_vrr->adjust.v_total_min = v_total;
242 	in_out_vrr->adjust.v_total_max = v_total;
243 }
244 
245 static void apply_below_the_range(struct core_freesync *core_freesync,
246 		const struct dc_stream_state *stream,
247 		unsigned int last_render_time_in_us,
248 		struct mod_vrr_params *in_out_vrr)
249 {
250 	unsigned int inserted_frame_duration_in_us = 0;
251 	unsigned int mid_point_frames_ceil = 0;
252 	unsigned int mid_point_frames_floor = 0;
253 	unsigned int frame_time_in_us = 0;
254 	unsigned int delta_from_mid_point_in_us_1 = 0xFFFFFFFF;
255 	unsigned int delta_from_mid_point_in_us_2 = 0xFFFFFFFF;
256 	unsigned int frames_to_insert = 0;
257 	unsigned int delta_from_mid_point_delta_in_us;
258 	unsigned int max_render_time_in_us =
259 			in_out_vrr->max_duration_in_us - in_out_vrr->btr.margin_in_us;
260 
261 	/* Program BTR */
262 	if ((last_render_time_in_us + in_out_vrr->btr.margin_in_us / 2) < max_render_time_in_us) {
263 		/* Exit Below the Range */
264 		if (in_out_vrr->btr.btr_active) {
265 			in_out_vrr->btr.frame_counter = 0;
266 			in_out_vrr->btr.btr_active = false;
267 		}
268 	} else if (last_render_time_in_us > (max_render_time_in_us + in_out_vrr->btr.margin_in_us / 2)) {
269 		/* Enter Below the Range */
270 		if (!in_out_vrr->btr.btr_active) {
271 			in_out_vrr->btr.btr_active = true;
272 		}
273 	}
274 
275 	/* BTR set to "not active" so disengage */
276 	if (!in_out_vrr->btr.btr_active) {
277 		in_out_vrr->btr.inserted_duration_in_us = 0;
278 		in_out_vrr->btr.frames_to_insert = 0;
279 		in_out_vrr->btr.frame_counter = 0;
280 
281 		/* Restore FreeSync */
282 		in_out_vrr->adjust.v_total_min =
283 			calc_v_total_from_refresh(stream,
284 				in_out_vrr->max_refresh_in_uhz);
285 		in_out_vrr->adjust.v_total_max =
286 			calc_v_total_from_refresh(stream,
287 				in_out_vrr->min_refresh_in_uhz);
288 	/* BTR set to "active" so engage */
289 	} else {
290 
291 		/* Calculate number of midPoint frames that could fit within
292 		 * the render time interval- take ceil of this value
293 		 */
294 		mid_point_frames_ceil = (last_render_time_in_us +
295 				in_out_vrr->btr.mid_point_in_us - 1) /
296 					in_out_vrr->btr.mid_point_in_us;
297 
298 		if (mid_point_frames_ceil > 0) {
299 			frame_time_in_us = last_render_time_in_us /
300 				mid_point_frames_ceil;
301 			delta_from_mid_point_in_us_1 =
302 				(in_out_vrr->btr.mid_point_in_us >
303 				frame_time_in_us) ?
304 				(in_out_vrr->btr.mid_point_in_us - frame_time_in_us) :
305 				(frame_time_in_us - in_out_vrr->btr.mid_point_in_us);
306 		}
307 
308 		/* Calculate number of midPoint frames that could fit within
309 		 * the render time interval- take floor of this value
310 		 */
311 		mid_point_frames_floor = last_render_time_in_us /
312 				in_out_vrr->btr.mid_point_in_us;
313 
314 		if (mid_point_frames_floor > 0) {
315 
316 			frame_time_in_us = last_render_time_in_us /
317 				mid_point_frames_floor;
318 			delta_from_mid_point_in_us_2 =
319 				(in_out_vrr->btr.mid_point_in_us >
320 				frame_time_in_us) ?
321 				(in_out_vrr->btr.mid_point_in_us - frame_time_in_us) :
322 				(frame_time_in_us - in_out_vrr->btr.mid_point_in_us);
323 		}
324 
325 		/* Choose number of frames to insert based on how close it
326 		 * can get to the mid point of the variable range.
327 		 */
328 		if ((frame_time_in_us / mid_point_frames_ceil) > in_out_vrr->min_duration_in_us &&
329 				(delta_from_mid_point_in_us_1 < delta_from_mid_point_in_us_2 ||
330 						mid_point_frames_floor < 2)) {
331 			frames_to_insert = mid_point_frames_ceil;
332 			delta_from_mid_point_delta_in_us = delta_from_mid_point_in_us_2 -
333 					delta_from_mid_point_in_us_1;
334 		} else {
335 			frames_to_insert = mid_point_frames_floor;
336 			delta_from_mid_point_delta_in_us = delta_from_mid_point_in_us_1 -
337 					delta_from_mid_point_in_us_2;
338 		}
339 
340 		/* Prefer current frame multiplier when BTR is enabled unless it drifts
341 		 * too far from the midpoint
342 		 */
343 		if (in_out_vrr->btr.frames_to_insert != 0 &&
344 				delta_from_mid_point_delta_in_us < BTR_DRIFT_MARGIN) {
345 			if (((last_render_time_in_us / in_out_vrr->btr.frames_to_insert) <
346 					max_render_time_in_us) &&
347 				((last_render_time_in_us / in_out_vrr->btr.frames_to_insert) >
348 					in_out_vrr->min_duration_in_us))
349 				frames_to_insert = in_out_vrr->btr.frames_to_insert;
350 		}
351 
352 		/* Either we've calculated the number of frames to insert,
353 		 * or we need to insert min duration frames
354 		 */
355 		if (last_render_time_in_us / frames_to_insert <
356 				in_out_vrr->min_duration_in_us){
357 			frames_to_insert -= (frames_to_insert > 1) ?
358 					1 : 0;
359 		}
360 
361 		if (frames_to_insert > 0)
362 			inserted_frame_duration_in_us = last_render_time_in_us /
363 							frames_to_insert;
364 
365 		if (inserted_frame_duration_in_us < in_out_vrr->min_duration_in_us)
366 			inserted_frame_duration_in_us = in_out_vrr->min_duration_in_us;
367 
368 		/* Cache the calculated variables */
369 		in_out_vrr->btr.inserted_duration_in_us =
370 			inserted_frame_duration_in_us;
371 		in_out_vrr->btr.frames_to_insert = frames_to_insert;
372 		in_out_vrr->btr.frame_counter = frames_to_insert;
373 	}
374 }
375 
376 static void apply_fixed_refresh(struct core_freesync *core_freesync,
377 		const struct dc_stream_state *stream,
378 		unsigned int last_render_time_in_us,
379 		struct mod_vrr_params *in_out_vrr)
380 {
381 	bool update = false;
382 	unsigned int max_render_time_in_us = in_out_vrr->max_duration_in_us;
383 
384 	/* Compute the exit refresh rate and exit frame duration */
385 	unsigned int exit_refresh_rate_in_milli_hz = ((1000000000/max_render_time_in_us)
386 			+ (1000*FIXED_REFRESH_EXIT_MARGIN_IN_HZ));
387 	unsigned int exit_frame_duration_in_us = 1000000000/exit_refresh_rate_in_milli_hz;
388 
389 	if (last_render_time_in_us < exit_frame_duration_in_us) {
390 		/* Exit Fixed Refresh mode */
391 		if (in_out_vrr->fixed.fixed_active) {
392 			in_out_vrr->fixed.frame_counter++;
393 
394 			if (in_out_vrr->fixed.frame_counter >
395 					FIXED_REFRESH_EXIT_FRAME_COUNT) {
396 				in_out_vrr->fixed.frame_counter = 0;
397 				in_out_vrr->fixed.fixed_active = false;
398 				in_out_vrr->fixed.target_refresh_in_uhz = 0;
399 				update = true;
400 			}
401 		}
402 	} else if (last_render_time_in_us > max_render_time_in_us) {
403 		/* Enter Fixed Refresh mode */
404 		if (!in_out_vrr->fixed.fixed_active) {
405 			in_out_vrr->fixed.frame_counter++;
406 
407 			if (in_out_vrr->fixed.frame_counter >
408 					FIXED_REFRESH_ENTER_FRAME_COUNT) {
409 				in_out_vrr->fixed.frame_counter = 0;
410 				in_out_vrr->fixed.fixed_active = true;
411 				in_out_vrr->fixed.target_refresh_in_uhz =
412 						in_out_vrr->max_refresh_in_uhz;
413 				update = true;
414 			}
415 		}
416 	}
417 
418 	if (update) {
419 		if (in_out_vrr->fixed.fixed_active) {
420 			in_out_vrr->adjust.v_total_min =
421 				calc_v_total_from_refresh(
422 				stream, in_out_vrr->max_refresh_in_uhz);
423 			in_out_vrr->adjust.v_total_max =
424 					in_out_vrr->adjust.v_total_min;
425 		} else {
426 			in_out_vrr->adjust.v_total_min =
427 				calc_v_total_from_refresh(stream,
428 					in_out_vrr->max_refresh_in_uhz);
429 			in_out_vrr->adjust.v_total_max =
430 				calc_v_total_from_refresh(stream,
431 					in_out_vrr->min_refresh_in_uhz);
432 		}
433 	}
434 }
435 
436 static bool vrr_settings_require_update(struct core_freesync *core_freesync,
437 		struct mod_freesync_config *in_config,
438 		unsigned int min_refresh_in_uhz,
439 		unsigned int max_refresh_in_uhz,
440 		struct mod_vrr_params *in_vrr)
441 {
442 	if (in_vrr->state != in_config->state) {
443 		return true;
444 	} else if (in_vrr->state == VRR_STATE_ACTIVE_FIXED &&
445 			in_vrr->fixed.target_refresh_in_uhz !=
446 					in_config->fixed_refresh_in_uhz) {
447 		return true;
448 	} else if (in_vrr->min_refresh_in_uhz != min_refresh_in_uhz) {
449 		return true;
450 	} else if (in_vrr->max_refresh_in_uhz != max_refresh_in_uhz) {
451 		return true;
452 	}
453 
454 	return false;
455 }
456 
457 bool mod_freesync_get_vmin_vmax(struct mod_freesync *mod_freesync,
458 		const struct dc_stream_state *stream,
459 		unsigned int *vmin,
460 		unsigned int *vmax)
461 {
462 	*vmin = stream->adjust.v_total_min;
463 	*vmax = stream->adjust.v_total_max;
464 
465 	return true;
466 }
467 
468 bool mod_freesync_get_v_position(struct mod_freesync *mod_freesync,
469 		struct dc_stream_state *stream,
470 		unsigned int *nom_v_pos,
471 		unsigned int *v_pos)
472 {
473 	struct core_freesync *core_freesync = NULL;
474 	struct crtc_position position;
475 
476 	if (mod_freesync == NULL)
477 		return false;
478 
479 	core_freesync = MOD_FREESYNC_TO_CORE(mod_freesync);
480 
481 	if (dc_stream_get_crtc_position(core_freesync->dc, &stream, 1,
482 					&position.vertical_count,
483 					&position.nominal_vcount)) {
484 
485 		*nom_v_pos = position.nominal_vcount;
486 		*v_pos = position.vertical_count;
487 
488 		return true;
489 	}
490 
491 	return false;
492 }
493 
494 static void build_vrr_infopacket_data_v1(const struct mod_vrr_params *vrr,
495 		struct dc_info_packet *infopacket)
496 {
497 	/* PB1 = 0x1A (24bit AMD IEEE OUI (0x00001A) - Byte 0) */
498 	infopacket->sb[1] = 0x1A;
499 
500 	/* PB2 = 0x00 (24bit AMD IEEE OUI (0x00001A) - Byte 1) */
501 	infopacket->sb[2] = 0x00;
502 
503 	/* PB3 = 0x00 (24bit AMD IEEE OUI (0x00001A) - Byte 2) */
504 	infopacket->sb[3] = 0x00;
505 
506 	/* PB4 = Reserved */
507 
508 	/* PB5 = Reserved */
509 
510 	/* PB6 = [Bits 7:3 = Reserved] */
511 
512 	/* PB6 = [Bit 0 = FreeSync Supported] */
513 	if (vrr->state != VRR_STATE_UNSUPPORTED)
514 		infopacket->sb[6] |= 0x01;
515 
516 	/* PB6 = [Bit 1 = FreeSync Enabled] */
517 	if (vrr->state != VRR_STATE_DISABLED &&
518 			vrr->state != VRR_STATE_UNSUPPORTED)
519 		infopacket->sb[6] |= 0x02;
520 
521 	/* PB6 = [Bit 2 = FreeSync Active] */
522 	if (vrr->state == VRR_STATE_ACTIVE_VARIABLE ||
523 			vrr->state == VRR_STATE_ACTIVE_FIXED)
524 		infopacket->sb[6] |= 0x04;
525 
526 	// For v1 & 2 infoframes program nominal if non-fs mode, otherwise full range
527 	/* PB7 = FreeSync Minimum refresh rate (Hz) */
528 	if (vrr->state == VRR_STATE_ACTIVE_VARIABLE ||
529 			vrr->state == VRR_STATE_ACTIVE_FIXED) {
530 		infopacket->sb[7] = (unsigned char)((vrr->min_refresh_in_uhz + 500000) / 1000000);
531 	} else {
532 		infopacket->sb[7] = (unsigned char)((vrr->max_refresh_in_uhz + 500000) / 1000000);
533 	}
534 
535 	/* PB8 = FreeSync Maximum refresh rate (Hz)
536 	 * Note: We should never go above the field rate of the mode timing set.
537 	 */
538 	infopacket->sb[8] = (unsigned char)((vrr->max_refresh_in_uhz + 500000) / 1000000);
539 
540 	//FreeSync HDR
541 	infopacket->sb[9] = 0;
542 	infopacket->sb[10] = 0;
543 }
544 
545 static void build_vrr_infopacket_data_v3(const struct mod_vrr_params *vrr,
546 		struct dc_info_packet *infopacket)
547 {
548 	/* PB1 = 0x1A (24bit AMD IEEE OUI (0x00001A) - Byte 0) */
549 	infopacket->sb[1] = 0x1A;
550 
551 	/* PB2 = 0x00 (24bit AMD IEEE OUI (0x00001A) - Byte 1) */
552 	infopacket->sb[2] = 0x00;
553 
554 	/* PB3 = 0x00 (24bit AMD IEEE OUI (0x00001A) - Byte 2) */
555 	infopacket->sb[3] = 0x00;
556 
557 	/* PB4 = Reserved */
558 
559 	/* PB5 = Reserved */
560 
561 	/* PB6 = [Bits 7:3 = Reserved] */
562 
563 	/* PB6 = [Bit 0 = FreeSync Supported] */
564 	if (vrr->state != VRR_STATE_UNSUPPORTED)
565 		infopacket->sb[6] |= 0x01;
566 
567 	/* PB6 = [Bit 1 = FreeSync Enabled] */
568 	if (vrr->state != VRR_STATE_DISABLED &&
569 			vrr->state != VRR_STATE_UNSUPPORTED)
570 		infopacket->sb[6] |= 0x02;
571 
572 	/* PB6 = [Bit 2 = FreeSync Active] */
573 	if (vrr->state == VRR_STATE_ACTIVE_VARIABLE ||
574 			vrr->state == VRR_STATE_ACTIVE_FIXED)
575 		infopacket->sb[6] |= 0x04;
576 
577 	if (vrr->state == VRR_STATE_ACTIVE_FIXED) {
578 		/* PB7 = FreeSync Minimum refresh rate (Hz) */
579 		infopacket->sb[7] = (unsigned char)((vrr->fixed_refresh_in_uhz + 500000) / 1000000);
580 		/* PB8 = FreeSync Maximum refresh rate (Hz) */
581 		infopacket->sb[8] = (unsigned char)((vrr->fixed_refresh_in_uhz + 500000) / 1000000);
582 	} else if (vrr->state == VRR_STATE_ACTIVE_VARIABLE) {
583 		/* PB7 = FreeSync Minimum refresh rate (Hz) */
584 		infopacket->sb[7] = (unsigned char)((vrr->min_refresh_in_uhz + 500000) / 1000000);
585 		/* PB8 = FreeSync Maximum refresh rate (Hz) */
586 		infopacket->sb[8] = (unsigned char)((vrr->max_refresh_in_uhz + 500000) / 1000000);
587 	} else {
588 		// Non-fs case, program nominal range
589 		/* PB7 = FreeSync Minimum refresh rate (Hz) */
590 		infopacket->sb[7] = (unsigned char)((vrr->max_refresh_in_uhz + 500000) / 1000000);
591 		/* PB8 = FreeSync Maximum refresh rate (Hz) */
592 		infopacket->sb[8] = (unsigned char)((vrr->max_refresh_in_uhz + 500000) / 1000000);
593 	}
594 
595 	//FreeSync HDR
596 	infopacket->sb[9] = 0;
597 	infopacket->sb[10] = 0;
598 }
599 
600 static void build_vrr_infopacket_fs2_data(enum color_transfer_func app_tf,
601 		struct dc_info_packet *infopacket)
602 {
603 	if (app_tf != TRANSFER_FUNC_UNKNOWN) {
604 		infopacket->valid = true;
605 
606 		infopacket->sb[6] |= 0x08;  // PB6 = [Bit 3 = Native Color Active]
607 
608 		if (app_tf == TRANSFER_FUNC_GAMMA_22) {
609 			infopacket->sb[9] |= 0x04;  // PB6 = [Bit 2 = Gamma 2.2 EOTF Active]
610 		}
611 	}
612 }
613 
614 static void build_vrr_infopacket_header_v1(enum signal_type signal,
615 		struct dc_info_packet *infopacket,
616 		unsigned int *payload_size)
617 {
618 	if (dc_is_hdmi_signal(signal)) {
619 
620 		/* HEADER */
621 
622 		/* HB0  = Packet Type = 0x83 (Source Product
623 		 *	  Descriptor InfoFrame)
624 		 */
625 		infopacket->hb0 = DC_HDMI_INFOFRAME_TYPE_SPD;
626 
627 		/* HB1  = Version = 0x01 */
628 		infopacket->hb1 = 0x01;
629 
630 		/* HB2  = [Bits 7:5 = 0] [Bits 4:0 = Length = 0x08] */
631 		infopacket->hb2 = 0x08;
632 
633 		*payload_size = 0x08;
634 
635 	} else if (dc_is_dp_signal(signal)) {
636 
637 		/* HEADER */
638 
639 		/* HB0  = Secondary-data Packet ID = 0 - Only non-zero
640 		 *	  when used to associate audio related info packets
641 		 */
642 		infopacket->hb0 = 0x00;
643 
644 		/* HB1  = Packet Type = 0x83 (Source Product
645 		 *	  Descriptor InfoFrame)
646 		 */
647 		infopacket->hb1 = DC_HDMI_INFOFRAME_TYPE_SPD;
648 
649 		/* HB2  = [Bits 7:0 = Least significant eight bits -
650 		 *	  For INFOFRAME, the value must be 1Bh]
651 		 */
652 		infopacket->hb2 = 0x1B;
653 
654 		/* HB3  = [Bits 7:2 = INFOFRAME SDP Version Number = 0x1]
655 		 *	  [Bits 1:0 = Most significant two bits = 0x00]
656 		 */
657 		infopacket->hb3 = 0x04;
658 
659 		*payload_size = 0x1B;
660 	}
661 }
662 
663 static void build_vrr_infopacket_header_v2(enum signal_type signal,
664 		struct dc_info_packet *infopacket,
665 		unsigned int *payload_size)
666 {
667 	if (dc_is_hdmi_signal(signal)) {
668 
669 		/* HEADER */
670 
671 		/* HB0  = Packet Type = 0x83 (Source Product
672 		 *	  Descriptor InfoFrame)
673 		 */
674 		infopacket->hb0 = DC_HDMI_INFOFRAME_TYPE_SPD;
675 
676 		/* HB1  = Version = 0x02 */
677 		infopacket->hb1 = 0x02;
678 
679 		/* HB2  = [Bits 7:5 = 0] [Bits 4:0 = Length = 0x09] */
680 		infopacket->hb2 = 0x09;
681 
682 		*payload_size = 0x0A;
683 
684 	} else if (dc_is_dp_signal(signal)) {
685 
686 		/* HEADER */
687 
688 		/* HB0  = Secondary-data Packet ID = 0 - Only non-zero
689 		 *	  when used to associate audio related info packets
690 		 */
691 		infopacket->hb0 = 0x00;
692 
693 		/* HB1  = Packet Type = 0x83 (Source Product
694 		 *	  Descriptor InfoFrame)
695 		 */
696 		infopacket->hb1 = DC_HDMI_INFOFRAME_TYPE_SPD;
697 
698 		/* HB2  = [Bits 7:0 = Least significant eight bits -
699 		 *	  For INFOFRAME, the value must be 1Bh]
700 		 */
701 		infopacket->hb2 = 0x1B;
702 
703 		/* HB3  = [Bits 7:2 = INFOFRAME SDP Version Number = 0x2]
704 		 *	  [Bits 1:0 = Most significant two bits = 0x00]
705 		 */
706 		infopacket->hb3 = 0x08;
707 
708 		*payload_size = 0x1B;
709 	}
710 }
711 
712 static void build_vrr_infopacket_checksum(unsigned int *payload_size,
713 		struct dc_info_packet *infopacket)
714 {
715 	/* Calculate checksum */
716 	unsigned int idx = 0;
717 	unsigned char checksum = 0;
718 
719 	checksum += infopacket->hb0;
720 	checksum += infopacket->hb1;
721 	checksum += infopacket->hb2;
722 	checksum += infopacket->hb3;
723 
724 	for (idx = 1; idx <= *payload_size; idx++)
725 		checksum += infopacket->sb[idx];
726 
727 	/* PB0 = Checksum (one byte complement) */
728 	infopacket->sb[0] = (unsigned char)(0x100 - checksum);
729 
730 	infopacket->valid = true;
731 }
732 
733 static void build_vrr_infopacket_v1(enum signal_type signal,
734 		const struct mod_vrr_params *vrr,
735 		struct dc_info_packet *infopacket)
736 {
737 	/* SPD info packet for FreeSync */
738 	unsigned int payload_size = 0;
739 
740 	build_vrr_infopacket_header_v1(signal, infopacket, &payload_size);
741 	build_vrr_infopacket_data_v1(vrr, infopacket);
742 	build_vrr_infopacket_checksum(&payload_size, infopacket);
743 
744 	infopacket->valid = true;
745 }
746 
747 static void build_vrr_infopacket_v2(enum signal_type signal,
748 		const struct mod_vrr_params *vrr,
749 		enum color_transfer_func app_tf,
750 		struct dc_info_packet *infopacket)
751 {
752 	unsigned int payload_size = 0;
753 
754 	build_vrr_infopacket_header_v2(signal, infopacket, &payload_size);
755 	build_vrr_infopacket_data_v1(vrr, infopacket);
756 
757 	build_vrr_infopacket_fs2_data(app_tf, infopacket);
758 
759 	build_vrr_infopacket_checksum(&payload_size, infopacket);
760 
761 	infopacket->valid = true;
762 }
763 
764 static void build_vrr_infopacket_v3(enum signal_type signal,
765 		const struct mod_vrr_params *vrr,
766 		enum color_transfer_func app_tf,
767 		struct dc_info_packet *infopacket)
768 {
769 	unsigned int payload_size = 0;
770 
771 	build_vrr_infopacket_header_v2(signal, infopacket, &payload_size);
772 	build_vrr_infopacket_data_v3(vrr, infopacket);
773 
774 	build_vrr_infopacket_fs2_data(app_tf, infopacket);
775 
776 	build_vrr_infopacket_checksum(&payload_size, infopacket);
777 
778 	infopacket->valid = true;
779 }
780 
781 void mod_freesync_build_vrr_infopacket(struct mod_freesync *mod_freesync,
782 		const struct dc_stream_state *stream,
783 		const struct mod_vrr_params *vrr,
784 		enum vrr_packet_type packet_type,
785 		enum color_transfer_func app_tf,
786 		struct dc_info_packet *infopacket)
787 {
788 	/* SPD info packet for FreeSync
789 	 * VTEM info packet for HdmiVRR
790 	 * Check if Freesync is supported. Return if false. If true,
791 	 * set the corresponding bit in the info packet
792 	 */
793 	if (!vrr->supported || (!vrr->send_info_frame))
794 		return;
795 
796 	switch (packet_type) {
797 	case PACKET_TYPE_FS_V3:
798 		build_vrr_infopacket_v3(stream->signal, vrr, app_tf, infopacket);
799 		break;
800 	case PACKET_TYPE_FS_V2:
801 		build_vrr_infopacket_v2(stream->signal, vrr, app_tf, infopacket);
802 		break;
803 	case PACKET_TYPE_VRR:
804 	case PACKET_TYPE_FS_V1:
805 	default:
806 		build_vrr_infopacket_v1(stream->signal, vrr, infopacket);
807 	}
808 }
809 
810 void mod_freesync_build_vrr_params(struct mod_freesync *mod_freesync,
811 		const struct dc_stream_state *stream,
812 		struct mod_freesync_config *in_config,
813 		struct mod_vrr_params *in_out_vrr)
814 {
815 	struct core_freesync *core_freesync = NULL;
816 	unsigned long long nominal_field_rate_in_uhz = 0;
817 	unsigned long long rounded_nominal_in_uhz = 0;
818 	unsigned int refresh_range = 0;
819 	unsigned long long min_refresh_in_uhz = 0;
820 	unsigned long long max_refresh_in_uhz = 0;
821 
822 	if (mod_freesync == NULL)
823 		return;
824 
825 	core_freesync = MOD_FREESYNC_TO_CORE(mod_freesync);
826 
827 	/* Calculate nominal field rate for stream */
828 	nominal_field_rate_in_uhz =
829 			mod_freesync_calc_nominal_field_rate(stream);
830 
831 	min_refresh_in_uhz = in_config->min_refresh_in_uhz;
832 	max_refresh_in_uhz = in_config->max_refresh_in_uhz;
833 
834 	// Full range may be larger than current video timing, so cap at nominal
835 	if (max_refresh_in_uhz > nominal_field_rate_in_uhz)
836 		max_refresh_in_uhz = nominal_field_rate_in_uhz;
837 
838 	// Full range may be larger than current video timing, so cap at nominal
839 	if (min_refresh_in_uhz > max_refresh_in_uhz)
840 		min_refresh_in_uhz = max_refresh_in_uhz;
841 
842 	// If a monitor reports exactly max refresh of 2x of min, enforce it on nominal
843 	rounded_nominal_in_uhz =
844 			div_u64(nominal_field_rate_in_uhz + 50000, 100000) * 100000;
845 	if (in_config->max_refresh_in_uhz == (2 * in_config->min_refresh_in_uhz) &&
846 		in_config->max_refresh_in_uhz == rounded_nominal_in_uhz)
847 		min_refresh_in_uhz = div_u64(nominal_field_rate_in_uhz, 2);
848 
849 	if (!vrr_settings_require_update(core_freesync,
850 			in_config, (unsigned int)min_refresh_in_uhz, (unsigned int)max_refresh_in_uhz,
851 			in_out_vrr))
852 		return;
853 
854 	in_out_vrr->state = in_config->state;
855 	in_out_vrr->send_info_frame = in_config->vsif_supported;
856 
857 	if (in_config->state == VRR_STATE_UNSUPPORTED) {
858 		in_out_vrr->state = VRR_STATE_UNSUPPORTED;
859 		in_out_vrr->supported = false;
860 		in_out_vrr->adjust.v_total_min = stream->timing.v_total;
861 		in_out_vrr->adjust.v_total_max = stream->timing.v_total;
862 
863 		return;
864 
865 	} else {
866 		in_out_vrr->min_refresh_in_uhz = (unsigned int)min_refresh_in_uhz;
867 		in_out_vrr->max_duration_in_us =
868 				calc_duration_in_us_from_refresh_in_uhz(
869 						(unsigned int)min_refresh_in_uhz);
870 
871 		in_out_vrr->max_refresh_in_uhz = (unsigned int)max_refresh_in_uhz;
872 		in_out_vrr->min_duration_in_us =
873 				calc_duration_in_us_from_refresh_in_uhz(
874 						(unsigned int)max_refresh_in_uhz);
875 
876 		if (in_config->state == VRR_STATE_ACTIVE_FIXED)
877 			in_out_vrr->fixed_refresh_in_uhz = in_config->fixed_refresh_in_uhz;
878 		else
879 			in_out_vrr->fixed_refresh_in_uhz = 0;
880 
881 		refresh_range = in_out_vrr->max_refresh_in_uhz -
882 				in_out_vrr->min_refresh_in_uhz;
883 
884 		in_out_vrr->supported = true;
885 	}
886 
887 	in_out_vrr->fixed.ramping_active = in_config->ramping;
888 
889 	in_out_vrr->btr.btr_enabled = in_config->btr;
890 
891 	if (in_out_vrr->max_refresh_in_uhz < (2 * in_out_vrr->min_refresh_in_uhz))
892 		in_out_vrr->btr.btr_enabled = false;
893 	else {
894 		in_out_vrr->btr.margin_in_us = in_out_vrr->max_duration_in_us -
895 				2 * in_out_vrr->min_duration_in_us;
896 		if (in_out_vrr->btr.margin_in_us > BTR_MAX_MARGIN)
897 			in_out_vrr->btr.margin_in_us = BTR_MAX_MARGIN;
898 	}
899 
900 	in_out_vrr->btr.btr_active = false;
901 	in_out_vrr->btr.inserted_duration_in_us = 0;
902 	in_out_vrr->btr.frames_to_insert = 0;
903 	in_out_vrr->btr.frame_counter = 0;
904 	in_out_vrr->fixed.fixed_active = false;
905 	in_out_vrr->fixed.target_refresh_in_uhz = 0;
906 
907 	in_out_vrr->btr.mid_point_in_us =
908 				(in_out_vrr->min_duration_in_us +
909 				 in_out_vrr->max_duration_in_us) / 2;
910 
911 	if (in_out_vrr->state == VRR_STATE_UNSUPPORTED) {
912 		in_out_vrr->adjust.v_total_min = stream->timing.v_total;
913 		in_out_vrr->adjust.v_total_max = stream->timing.v_total;
914 	} else if (in_out_vrr->state == VRR_STATE_DISABLED) {
915 		in_out_vrr->adjust.v_total_min = stream->timing.v_total;
916 		in_out_vrr->adjust.v_total_max = stream->timing.v_total;
917 	} else if (in_out_vrr->state == VRR_STATE_INACTIVE) {
918 		in_out_vrr->adjust.v_total_min = stream->timing.v_total;
919 		in_out_vrr->adjust.v_total_max = stream->timing.v_total;
920 	} else if (in_out_vrr->state == VRR_STATE_ACTIVE_VARIABLE &&
921 			refresh_range >= MIN_REFRESH_RANGE_IN_US) {
922 
923 		in_out_vrr->adjust.v_total_min =
924 			calc_v_total_from_refresh(stream,
925 				in_out_vrr->max_refresh_in_uhz);
926 		in_out_vrr->adjust.v_total_max =
927 			calc_v_total_from_refresh(stream,
928 				in_out_vrr->min_refresh_in_uhz);
929 	} else if (in_out_vrr->state == VRR_STATE_ACTIVE_FIXED) {
930 		in_out_vrr->fixed.target_refresh_in_uhz =
931 				in_out_vrr->fixed_refresh_in_uhz;
932 		if (in_out_vrr->fixed.ramping_active &&
933 				in_out_vrr->fixed.fixed_active) {
934 			/* Do not update vtotals if ramping is already active
935 			 * in order to continue ramp from current refresh.
936 			 */
937 			in_out_vrr->fixed.fixed_active = true;
938 		} else {
939 			in_out_vrr->fixed.fixed_active = true;
940 			in_out_vrr->adjust.v_total_min =
941 				calc_v_total_from_refresh(stream,
942 					in_out_vrr->fixed.target_refresh_in_uhz);
943 			in_out_vrr->adjust.v_total_max =
944 				in_out_vrr->adjust.v_total_min;
945 		}
946 	} else {
947 		in_out_vrr->state = VRR_STATE_INACTIVE;
948 		in_out_vrr->adjust.v_total_min = stream->timing.v_total;
949 		in_out_vrr->adjust.v_total_max = stream->timing.v_total;
950 	}
951 }
952 
953 void mod_freesync_handle_preflip(struct mod_freesync *mod_freesync,
954 		const struct dc_plane_state *plane,
955 		const struct dc_stream_state *stream,
956 		unsigned int curr_time_stamp_in_us,
957 		struct mod_vrr_params *in_out_vrr)
958 {
959 	struct core_freesync *core_freesync = NULL;
960 	unsigned int last_render_time_in_us = 0;
961 	unsigned int average_render_time_in_us = 0;
962 
963 	if (mod_freesync == NULL)
964 		return;
965 
966 	core_freesync = MOD_FREESYNC_TO_CORE(mod_freesync);
967 
968 	if (in_out_vrr->supported &&
969 			in_out_vrr->state == VRR_STATE_ACTIVE_VARIABLE) {
970 		unsigned int i = 0;
971 		unsigned int oldest_index = plane->time.index + 1;
972 
973 		if (oldest_index >= DC_PLANE_UPDATE_TIMES_MAX)
974 			oldest_index = 0;
975 
976 		last_render_time_in_us = curr_time_stamp_in_us -
977 				plane->time.prev_update_time_in_us;
978 
979 		// Sum off all entries except oldest one
980 		for (i = 0; i < DC_PLANE_UPDATE_TIMES_MAX; i++) {
981 			average_render_time_in_us +=
982 					plane->time.time_elapsed_in_us[i];
983 		}
984 		average_render_time_in_us -=
985 				plane->time.time_elapsed_in_us[oldest_index];
986 
987 		// Add render time for current flip
988 		average_render_time_in_us += last_render_time_in_us;
989 		average_render_time_in_us /= DC_PLANE_UPDATE_TIMES_MAX;
990 
991 		if (in_out_vrr->btr.btr_enabled) {
992 			apply_below_the_range(core_freesync,
993 					stream,
994 					last_render_time_in_us,
995 					in_out_vrr);
996 		} else {
997 			apply_fixed_refresh(core_freesync,
998 				stream,
999 				last_render_time_in_us,
1000 				in_out_vrr);
1001 		}
1002 
1003 	}
1004 }
1005 
1006 void mod_freesync_handle_v_update(struct mod_freesync *mod_freesync,
1007 		const struct dc_stream_state *stream,
1008 		struct mod_vrr_params *in_out_vrr)
1009 {
1010 	struct core_freesync *core_freesync = NULL;
1011 
1012 	if ((mod_freesync == NULL) || (stream == NULL) || (in_out_vrr == NULL))
1013 		return;
1014 
1015 	core_freesync = MOD_FREESYNC_TO_CORE(mod_freesync);
1016 
1017 	if (in_out_vrr->supported == false)
1018 		return;
1019 
1020 	/* Below the Range Logic */
1021 
1022 	/* Only execute if in fullscreen mode */
1023 	if (in_out_vrr->state == VRR_STATE_ACTIVE_VARIABLE &&
1024 					in_out_vrr->btr.btr_active) {
1025 		/* TODO: pass in flag for Pre-DCE12 ASIC
1026 		 * in order for frame variable duration to take affect,
1027 		 * it needs to be done one VSYNC early, which is at
1028 		 * frameCounter == 1.
1029 		 * For DCE12 and newer updates to V_TOTAL_MIN/MAX
1030 		 * will take affect on current frame
1031 		 */
1032 		if (in_out_vrr->btr.frames_to_insert ==
1033 				in_out_vrr->btr.frame_counter) {
1034 			in_out_vrr->adjust.v_total_min =
1035 				calc_v_total_from_duration(stream,
1036 				in_out_vrr,
1037 				in_out_vrr->btr.inserted_duration_in_us);
1038 			in_out_vrr->adjust.v_total_max =
1039 				in_out_vrr->adjust.v_total_min;
1040 		}
1041 
1042 		if (in_out_vrr->btr.frame_counter > 0)
1043 			in_out_vrr->btr.frame_counter--;
1044 
1045 		/* Restore FreeSync */
1046 		if (in_out_vrr->btr.frame_counter == 0) {
1047 			in_out_vrr->adjust.v_total_min =
1048 				calc_v_total_from_refresh(stream,
1049 				in_out_vrr->max_refresh_in_uhz);
1050 			in_out_vrr->adjust.v_total_max =
1051 				calc_v_total_from_refresh(stream,
1052 				in_out_vrr->min_refresh_in_uhz);
1053 		}
1054 	}
1055 
1056 	/* If in fullscreen freesync mode or in video, do not program
1057 	 * static screen ramp values
1058 	 */
1059 	if (in_out_vrr->state == VRR_STATE_ACTIVE_VARIABLE)
1060 		in_out_vrr->fixed.ramping_active = false;
1061 
1062 	/* Gradual Static Screen Ramping Logic */
1063 	/* Execute if ramp is active and user enabled freesync static screen*/
1064 	if (in_out_vrr->state == VRR_STATE_ACTIVE_FIXED &&
1065 				in_out_vrr->fixed.ramping_active) {
1066 		update_v_total_for_static_ramp(
1067 				core_freesync, stream, in_out_vrr);
1068 	}
1069 }
1070 
1071 void mod_freesync_get_settings(struct mod_freesync *mod_freesync,
1072 		const struct mod_vrr_params *vrr,
1073 		unsigned int *v_total_min, unsigned int *v_total_max,
1074 		unsigned int *event_triggers,
1075 		unsigned int *window_min, unsigned int *window_max,
1076 		unsigned int *lfc_mid_point_in_us,
1077 		unsigned int *inserted_frames,
1078 		unsigned int *inserted_duration_in_us)
1079 {
1080 	if (mod_freesync == NULL)
1081 		return;
1082 
1083 	if (vrr->supported) {
1084 		*v_total_min = vrr->adjust.v_total_min;
1085 		*v_total_max = vrr->adjust.v_total_max;
1086 		*event_triggers = 0;
1087 		*lfc_mid_point_in_us = vrr->btr.mid_point_in_us;
1088 		*inserted_frames = vrr->btr.frames_to_insert;
1089 		*inserted_duration_in_us = vrr->btr.inserted_duration_in_us;
1090 	}
1091 }
1092 
1093 unsigned long long mod_freesync_calc_nominal_field_rate(
1094 			const struct dc_stream_state *stream)
1095 {
1096 	unsigned long long nominal_field_rate_in_uhz = 0;
1097 	unsigned int total = stream->timing.h_total * stream->timing.v_total;
1098 
1099 	/* Calculate nominal field rate for stream, rounded up to nearest integer */
1100 	nominal_field_rate_in_uhz = stream->timing.pix_clk_100hz;
1101 	nominal_field_rate_in_uhz *= 100000000ULL;
1102 
1103 	nominal_field_rate_in_uhz =	div_u64(nominal_field_rate_in_uhz, total);
1104 
1105 	return nominal_field_rate_in_uhz;
1106 }
1107 
1108 bool mod_freesync_is_valid_range(struct mod_freesync *mod_freesync,
1109 		const struct dc_stream_state *stream,
1110 		uint32_t min_refresh_cap_in_uhz,
1111 		uint32_t max_refresh_cap_in_uhz,
1112 		uint32_t min_refresh_request_in_uhz,
1113 		uint32_t max_refresh_request_in_uhz)
1114 {
1115 	/* Calculate nominal field rate for stream */
1116 	unsigned long long nominal_field_rate_in_uhz =
1117 			mod_freesync_calc_nominal_field_rate(stream);
1118 
1119 	/* Typically nominal refresh calculated can have some fractional part.
1120 	 * Allow for some rounding error of actual video timing by taking floor
1121 	 * of caps and request. Round the nominal refresh rate.
1122 	 *
1123 	 * Dividing will convert everything to units in Hz although input
1124 	 * variable name is in uHz!
1125 	 *
1126 	 * Also note, this takes care of rounding error on the nominal refresh
1127 	 * so by rounding error we only expect it to be off by a small amount,
1128 	 * such as < 0.1 Hz. i.e. 143.9xxx or 144.1xxx.
1129 	 *
1130 	 * Example 1. Caps    Min = 40 Hz, Max = 144 Hz
1131 	 *            Request Min = 40 Hz, Max = 144 Hz
1132 	 *                    Nominal = 143.5x Hz rounded to 144 Hz
1133 	 *            This function should allow this as valid request
1134 	 *
1135 	 * Example 2. Caps    Min = 40 Hz, Max = 144 Hz
1136 	 *            Request Min = 40 Hz, Max = 144 Hz
1137 	 *                    Nominal = 144.4x Hz rounded to 144 Hz
1138 	 *            This function should allow this as valid request
1139 	 *
1140 	 * Example 3. Caps    Min = 40 Hz, Max = 144 Hz
1141 	 *            Request Min = 40 Hz, Max = 144 Hz
1142 	 *                    Nominal = 120.xx Hz rounded to 120 Hz
1143 	 *            This function should return NOT valid since the requested
1144 	 *            max is greater than current timing's nominal
1145 	 *
1146 	 * Example 4. Caps    Min = 40 Hz, Max = 120 Hz
1147 	 *            Request Min = 40 Hz, Max = 120 Hz
1148 	 *                    Nominal = 144.xx Hz rounded to 144 Hz
1149 	 *            This function should return NOT valid since the nominal
1150 	 *            is greater than the capability's max refresh
1151 	 */
1152 	nominal_field_rate_in_uhz =
1153 			div_u64(nominal_field_rate_in_uhz + 500000, 1000000);
1154 	min_refresh_cap_in_uhz /= 1000000;
1155 	max_refresh_cap_in_uhz /= 1000000;
1156 	min_refresh_request_in_uhz /= 1000000;
1157 	max_refresh_request_in_uhz /= 1000000;
1158 
1159 	// Check nominal is within range
1160 	if (nominal_field_rate_in_uhz > max_refresh_cap_in_uhz ||
1161 		nominal_field_rate_in_uhz < min_refresh_cap_in_uhz)
1162 		return false;
1163 
1164 	// If nominal is less than max, limit the max allowed refresh rate
1165 	if (nominal_field_rate_in_uhz < max_refresh_cap_in_uhz)
1166 		max_refresh_cap_in_uhz = nominal_field_rate_in_uhz;
1167 
1168 	// Don't allow min > max
1169 	if (min_refresh_request_in_uhz > max_refresh_request_in_uhz)
1170 		return false;
1171 
1172 	// Check min is within range
1173 	if (min_refresh_request_in_uhz > max_refresh_cap_in_uhz ||
1174 		min_refresh_request_in_uhz < min_refresh_cap_in_uhz)
1175 		return false;
1176 
1177 	// Check max is within range
1178 	if (max_refresh_request_in_uhz > max_refresh_cap_in_uhz ||
1179 		max_refresh_request_in_uhz < min_refresh_cap_in_uhz)
1180 		return false;
1181 
1182 	// For variable range, check for at least 10 Hz range
1183 	if ((max_refresh_request_in_uhz != min_refresh_request_in_uhz) &&
1184 		(max_refresh_request_in_uhz - min_refresh_request_in_uhz < 10))
1185 		return false;
1186 
1187 	return true;
1188 }
1189 
1190