linux_kernel/drivers/gpu/drm/amd/display/modules/freesync/freesync.c

/*
 * Copyright 2016 Advanced Micro Devices, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 *
 * Authors: AMD
 *
 */

#include "dm_services.h"
#include "dc.h"
#include "mod_freesync.h"
#include "core_types.h"

#define MOD_FREESYNC_MAX_CONCURRENT_STREAMS  32

/* Refresh rate ramp at a fixed rate of 65 Hz/second */
#define STATIC_SCREEN_RAMP_DELTA_REFRESH_RATE_PER_FRAME ((1000 / 60) * 65)
/* Number of elements in the render times cache array */
#define RENDER_TIMES_MAX_COUNT 20
/* Threshold to exit BTR (to avoid frequent enter-exits at the lower limit) */
#define BTR_EXIT_MARGIN 2000
/* Number of consecutive frames to check before entering/exiting fixed refresh*/
#define FIXED_REFRESH_ENTER_FRAME_COUNT 5
#define FIXED_REFRESH_EXIT_FRAME_COUNT 5

#define FREESYNC_REGISTRY_NAME "freesync_v1"

#define FREESYNC_NO_STATIC_FOR_EXTERNAL_DP_REGKEY "DalFreeSyncNoStaticForExternalDp"

#define FREESYNC_NO_STATIC_FOR_INTERNAL_REGKEY "DalFreeSyncNoStaticForInternal"

struct gradual_static_ramp {
	bool ramp_is_active;
	bool ramp_direction_is_up;
	unsigned int ramp_current_frame_duration_in_ns;
};

struct time_cache {
	/* video (48Hz feature) related */
	unsigned int update_duration_in_ns;

	/* BTR/fixed refresh related */
	unsigned int prev_time_stamp_in_us;

	unsigned int min_render_time_in_us;
	unsigned int max_render_time_in_us;

	unsigned int render_times_index;
	unsigned int render_times[RENDER_TIMES_MAX_COUNT];
};

struct below_the_range {
	bool btr_active;
	bool program_btr;

	unsigned int mid_point_in_us;

	unsigned int inserted_frame_duration_in_us;
	unsigned int frames_to_insert;
	unsigned int frame_counter;
};

struct fixed_refresh {
	bool fixed_active;
	bool program_fixed;
	unsigned int frame_counter;
};

struct freesync_range {
	unsigned int min_refresh;
	unsigned int max_frame_duration;
	unsigned int vmax;

	unsigned int max_refresh;
	unsigned int min_frame_duration;
	unsigned int vmin;
};

struct freesync_state {
	bool fullscreen;
	bool static_screen;
	bool video;

	unsigned int nominal_refresh_rate_in_micro_hz;
	bool windowed_fullscreen;

	struct time_cache time;

	struct gradual_static_ramp static_ramp;
	struct below_the_range btr;
	struct fixed_refresh fixed_refresh;
	struct freesync_range freesync_range;
};

struct freesync_entity {
	struct dc_stream_state *stream;
	struct mod_freesync_caps *caps;
	struct freesync_state state;
	struct mod_freesync_user_enable user_enable;
};

struct freesync_registry_options {
	bool drr_external_supported;
	bool drr_internal_supported;
};

struct core_freesync {
	struct mod_freesync public;
	struct dc *dc;
	struct freesync_entity *map;
	int num_entities;
	struct freesync_registry_options opts;
};

#define MOD_FREESYNC_TO_CORE(mod_freesync)\
		container_of(mod_freesync, struct core_freesync, public)

static bool check_dc_support(const struct dc *dc)
{
	if (dc->stream_funcs.adjust_vmin_vmax == NULL)
		return false;

	return true;
}

struct mod_freesync *mod_freesync_create(struct dc *dc)
{
	struct core_freesync *core_freesync =
			kzalloc(sizeof(struct core_freesync), GFP_KERNEL);


	struct persistent_data_flag flag;

	int i, data = 0;

	if (core_freesync == NULL)
		goto fail_alloc_context;

	core_freesync->map = kzalloc(sizeof(struct freesync_entity) * MOD_FREESYNC_MAX_CONCURRENT_STREAMS,
				     GFP_KERNEL);

	if (core_freesync->map == NULL)
		goto fail_alloc_map;

	for (i = 0; i < MOD_FREESYNC_MAX_CONCURRENT_STREAMS; i++)
		core_freesync->map[i].stream = NULL;

	core_freesync->num_entities = 0;

	if (dc == NULL)
		goto fail_construct;

	core_freesync->dc = dc;

	if (!check_dc_support(dc))
		goto fail_construct;

	/* Create initial module folder in registry for freesync enable data */
	flag.save_per_edid = true;
	flag.save_per_link = false;
	dm_write_persistent_data(dc->ctx, NULL, FREESYNC_REGISTRY_NAME,
			NULL, NULL, 0, &flag);
	flag.save_per_edid = false;
	flag.save_per_link = false;

	if (dm_read_persistent_data(dc->ctx, NULL, NULL,
			FREESYNC_NO_STATIC_FOR_INTERNAL_REGKEY,
			&data, sizeof(data), &flag)) {
		core_freesync->opts.drr_internal_supported =
			(data & 1) ? false : true;
	}

	if (dm_read_persistent_data(dc->ctx, NULL, NULL,
			FREESYNC_NO_STATIC_FOR_EXTERNAL_DP_REGKEY,
			&data, sizeof(data), &flag)) {
		core_freesync->opts.drr_external_supported =
				(data & 1) ? false : true;
	}

	return &core_freesync->public;

fail_construct:
	kfree(core_freesync->map);

fail_alloc_map:
	kfree(core_freesync);

fail_alloc_context:
	return NULL;
}

void mod_freesync_destroy(struct mod_freesync *mod_freesync)
{
	if (mod_freesync != NULL) {
		int i;
		struct core_freesync *core_freesync =
				MOD_FREESYNC_TO_CORE(mod_freesync);

		for (i = 0; i < core_freesync->num_entities; i++)
			if (core_freesync->map[i].stream)
				dc_stream_release(core_freesync->map[i].stream);

		kfree(core_freesync->map);

		kfree(core_freesync);
	}
}

/* Given a specific dc_stream* this function finds its equivalent
 * on the core_freesync->map and returns the corresponding index
 */
static unsigned int map_index_from_stream(struct core_freesync *core_freesync,
		struct dc_stream_state *stream)
{
	unsigned int index = 0;

	for (index = 0; index < core_freesync->num_entities; index++) {
		if (core_freesync->map[index].stream == stream) {
			return index;
		}
	}
	/* Could not find stream requested */
	ASSERT(false);
	return index;
}

bool mod_freesync_add_stream(struct mod_freesync *mod_freesync,
		struct dc_stream_state *stream, struct mod_freesync_caps *caps)
{
	struct dc  *dc = NULL;
	struct core_freesync *core_freesync = NULL;
	int persistent_freesync_enable = 0;
	struct persistent_data_flag flag;
	unsigned int nom_refresh_rate_uhz;
	unsigned long long temp;

	if (mod_freesync == NULL)
		return false;

	core_freesync = MOD_FREESYNC_TO_CORE(mod_freesync);
	dc = core_freesync->dc;

	flag.save_per_edid = true;
	flag.save_per_link = false;

	if (core_freesync->num_entities < MOD_FREESYNC_MAX_CONCURRENT_STREAMS) {

		dc_stream_retain(stream);

		temp = stream->timing.pix_clk_khz;
		temp *= 1000ULL * 1000ULL * 1000ULL;
		temp = div_u64(temp, stream->timing.h_total);
		temp = div_u64(temp, stream->timing.v_total);

		nom_refresh_rate_uhz = (unsigned int) temp;

		core_freesync->map[core_freesync->num_entities].stream = stream;
		core_freesync->map[core_freesync->num_entities].caps = caps;

		core_freesync->map[core_freesync->num_entities].state.
			fullscreen = false;
		core_freesync->map[core_freesync->num_entities].state.
			static_screen = false;
		core_freesync->map[core_freesync->num_entities].state.
			video = false;
		core_freesync->map[core_freesync->num_entities].state.time.
			update_duration_in_ns = 0;
		core_freesync->map[core_freesync->num_entities].state.
			static_ramp.ramp_is_active = false;

		/* get persistent data from registry */
		if (dm_read_persistent_data(dc->ctx, stream->sink,
					FREESYNC_REGISTRY_NAME,
					"userenable", &persistent_freesync_enable,
					sizeof(int), &flag)) {
			core_freesync->map[core_freesync->num_entities].user_enable.
				enable_for_gaming =
				(persistent_freesync_enable & 1) ? true : false;
			core_freesync->map[core_freesync->num_entities].user_enable.
				enable_for_static =
				(persistent_freesync_enable & 2) ? true : false;
			core_freesync->map[core_freesync->num_entities].user_enable.
				enable_for_video =
				(persistent_freesync_enable & 4) ? true : false;
		} else {
			core_freesync->map[core_freesync->num_entities].user_enable.
					enable_for_gaming = false;
			core_freesync->map[core_freesync->num_entities].user_enable.
					enable_for_static = false;
			core_freesync->map[core_freesync->num_entities].user_enable.
					enable_for_video = false;
		}

		if (caps->supported &&
			nom_refresh_rate_uhz >= caps->min_refresh_in_micro_hz &&
			nom_refresh_rate_uhz <= caps->max_refresh_in_micro_hz)
			stream->ignore_msa_timing_param = 1;

		core_freesync->num_entities++;
		return true;
	}
	return false;
}

bool mod_freesync_remove_stream(struct mod_freesync *mod_freesync,
		struct dc_stream_state *stream)
{
	int i = 0;
	struct core_freesync *core_freesync = NULL;
	unsigned int index = 0;

	if (mod_freesync == NULL)
		return false;

	core_freesync = MOD_FREESYNC_TO_CORE(mod_freesync);
	index = map_index_from_stream(core_freesync, stream);

	dc_stream_release(core_freesync->map[index].stream);
	core_freesync->map[index].stream = NULL;
	/* To remove this entity, shift everything after down */
	for (i = index; i < core_freesync->num_entities - 1; i++)
		core_freesync->map[i] = core_freesync->map[i + 1];
	core_freesync->num_entities--;
	return true;
}

static void update_stream_freesync_context(struct core_freesync *core_freesync,
		struct dc_stream_state *stream)
{
	unsigned int index;
	struct freesync_context *ctx;

	ctx = &stream->freesync_ctx;

	index = map_index_from_stream(core_freesync, stream);

	ctx->supported = core_freesync->map[index].caps->supported;
	ctx->enabled = (core_freesync->map[index].user_enable.enable_for_gaming ||
		core_freesync->map[index].user_enable.enable_for_video ||
		core_freesync->map[index].user_enable.enable_for_static);
	ctx->active = (core_freesync->map[index].state.fullscreen ||
		core_freesync->map[index].state.video ||
		core_freesync->map[index].state.static_ramp.ramp_is_active);
	ctx->min_refresh_in_micro_hz =
			core_freesync->map[index].caps->min_refresh_in_micro_hz;
	ctx->nominal_refresh_in_micro_hz = core_freesync->
		map[index].state.nominal_refresh_rate_in_micro_hz;

}

static void update_stream(struct core_freesync *core_freesync,
		struct dc_stream_state *stream)
{
	unsigned int index = map_index_from_stream(core_freesync, stream);
	if (core_freesync->map[index].caps->supported) {
		stream->ignore_msa_timing_param = 1;
		update_stream_freesync_context(core_freesync, stream);
	}
}

static void calc_freesync_range(struct core_freesync *core_freesync,
		struct dc_stream_state *stream,
		struct freesync_state *state,
		unsigned int min_refresh_in_uhz,
		unsigned int max_refresh_in_uhz)
{
	unsigned int min_frame_duration_in_ns = 0, max_frame_duration_in_ns = 0;
	unsigned int index = map_index_from_stream(core_freesync, stream);
	uint32_t vtotal = stream->timing.v_total;

	if ((min_refresh_in_uhz == 0) || (max_refresh_in_uhz == 0)) {
		state->freesync_range.min_refresh =
				state->nominal_refresh_rate_in_micro_hz;
		state->freesync_range.max_refresh =
				state->nominal_refresh_rate_in_micro_hz;

		state->freesync_range.max_frame_duration = 0;
		state->freesync_range.min_frame_duration = 0;

		state->freesync_range.vmax = vtotal;
		state->freesync_range.vmin = vtotal;

		return;
	}

	min_frame_duration_in_ns = ((unsigned int) (div64_u64(
					(1000000000ULL * 1000000),
					max_refresh_in_uhz)));
	max_frame_duration_in_ns = ((unsigned int) (div64_u64(
		(1000000000ULL * 1000000),
		min_refresh_in_uhz)));

	state->freesync_range.min_refresh = min_refresh_in_uhz;
	state->freesync_range.max_refresh = max_refresh_in_uhz;

	state->freesync_range.max_frame_duration = max_frame_duration_in_ns;
	state->freesync_range.min_frame_duration = min_frame_duration_in_ns;

	state->freesync_range.vmax = div64_u64(div64_u64(((unsigned long long)(
		max_frame_duration_in_ns) * stream->timing.pix_clk_khz),
		stream->timing.h_total), 1000000);
	state->freesync_range.vmin = div64_u64(div64_u64(((unsigned long long)(
		min_frame_duration_in_ns) * stream->timing.pix_clk_khz),
		stream->timing.h_total), 1000000);

	/* vmin/vmax cannot be less than vtotal */
	if (state->freesync_range.vmin < vtotal) {
		/* Error of 1 is permissible */
		ASSERT((state->freesync_range.vmin + 1) >= vtotal);
		state->freesync_range.vmin = vtotal;
	}

	if (state->freesync_range.vmax < vtotal) {
		/* Error of 1 is permissible */
		ASSERT((state->freesync_range.vmax + 1) >= vtotal);
		state->freesync_range.vmax = vtotal;
	}

	/* Determine whether BTR can be supported */
	if (max_frame_duration_in_ns >=
			2 * min_frame_duration_in_ns)
		core_freesync->map[index].caps->btr_supported = true;
	else
		core_freesync->map[index].caps->btr_supported = false;

	/* Cache the time variables */
	state->time.max_render_time_in_us =
		max_frame_duration_in_ns / 1000;
	state->time.min_render_time_in_us =
		min_frame_duration_in_ns / 1000;
	state->btr.mid_point_in_us =
		(max_frame_duration_in_ns +
		min_frame_duration_in_ns) / 2000;
}

static void calc_v_total_from_duration(struct dc_stream_state *stream,
		unsigned int duration_in_ns, int *v_total_nominal)
{
	*v_total_nominal = div64_u64(div64_u64(((unsigned long long)(
				duration_in_ns) * stream->timing.pix_clk_khz),
				stream->timing.h_total), 1000000);
}

static void calc_v_total_for_static_ramp(struct core_freesync *core_freesync,
		struct dc_stream_state *stream,
		unsigned int index, int *v_total)
{
	unsigned int frame_duration = 0;

	struct gradual_static_ramp *static_ramp_variables =
				&core_freesync->map[index].state.static_ramp;

	/* Calc ratio between new and current frame duration with 3 digit */
	unsigned int frame_duration_ratio = div64_u64(1000000,
		(1000 +  div64_u64(((unsigned long long)(
		STATIC_SCREEN_RAMP_DELTA_REFRESH_RATE_PER_FRAME) *
		static_ramp_variables->ramp_current_frame_duration_in_ns),
		1000000000)));

	/* Calculate delta between new and current frame duration in ns */
	unsigned int frame_duration_delta = div64_u64(((unsigned long long)(
		static_ramp_variables->ramp_current_frame_duration_in_ns) *
		(1000 - frame_duration_ratio)), 1000);

	/* Adjust frame duration delta based on ratio between current and
	 * standard frame duration (frame duration at 60 Hz refresh rate).
	 */
	unsigned int ramp_rate_interpolated = div64_u64(((unsigned long long)(
		frame_duration_delta) * static_ramp_variables->
		ramp_current_frame_duration_in_ns), 16666666);

	/* Going to a higher refresh rate (lower frame duration) */
	if (static_ramp_variables->ramp_direction_is_up) {
		/* reduce frame duration */
		static_ramp_variables->ramp_current_frame_duration_in_ns -=
			ramp_rate_interpolated;

		/* min frame duration */
		frame_duration = ((unsigned int) (div64_u64(
			(1000000000ULL * 1000000),
			core_freesync->map[index].state.
			nominal_refresh_rate_in_micro_hz)));

		/* adjust for frame duration below min */
		if (static_ramp_variables->ramp_current_frame_duration_in_ns <=
			frame_duration) {

			static_ramp_variables->ramp_is_active = false;
			static_ramp_variables->
				ramp_current_frame_duration_in_ns =
				frame_duration;
		}
	/* Going to a lower refresh rate (larger frame duration) */
	} else {
		/* increase frame duration */
		static_ramp_variables->ramp_current_frame_duration_in_ns +=
			ramp_rate_interpolated;

		/* max frame duration */
		frame_duration = ((unsigned int) (div64_u64(
			(1000000000ULL * 1000000),
			core_freesync->map[index].caps->min_refresh_in_micro_hz)));

		/* adjust for frame duration above max */
		if (static_ramp_variables->ramp_current_frame_duration_in_ns >=
			frame_duration) {

			static_ramp_variables->ramp_is_active = false;
			static_ramp_variables->
				ramp_current_frame_duration_in_ns =
				frame_duration;
		}
	}

	calc_v_total_from_duration(stream, static_ramp_variables->
		ramp_current_frame_duration_in_ns, v_total);
}

static void reset_freesync_state_variables(struct freesync_state* state)
{
	state->static_ramp.ramp_is_active = false;
	if (state->nominal_refresh_rate_in_micro_hz)
		state->static_ramp.ramp_current_frame_duration_in_ns =
			((unsigned int) (div64_u64(
			(1000000000ULL * 1000000),
			state->nominal_refresh_rate_in_micro_hz)));

	state->btr.btr_active = false;
	state->btr.frame_counter = 0;
	state->btr.frames_to_insert = 0;
	state->btr.inserted_frame_duration_in_us = 0;
	state->btr.program_btr = false;

	state->fixed_refresh.fixed_active = false;
	state->fixed_refresh.program_fixed = false;
}
/*
 * Sets freesync mode on a stream depending on current freesync state.
 */
static bool set_freesync_on_streams(struct core_freesync *core_freesync,
		struct dc_stream_state **streams, int num_streams)
{
	int v_total_nominal = 0, v_total_min = 0, v_total_max = 0;
	unsigned int stream_idx, map_index = 0;
	struct freesync_state *state;

	if (num_streams == 0 || streams == NULL || num_streams > 1)
		return false;

	for (stream_idx = 0; stream_idx < num_streams; stream_idx++) {

		map_index = map_index_from_stream(core_freesync,
				streams[stream_idx]);

		state = &core_freesync->map[map_index].state;

		if (core_freesync->map[map_index].caps->supported) {

			/* Fullscreen has the topmost priority. If the
			 * fullscreen bit is set, we are in a fullscreen
			 * application where it should not matter if it is
			 * static screen. We should not check the static_screen
			 * or video bit.
			 *
			 * Special cases of fullscreen include btr and fixed
			 * refresh. We program btr on every flip and involves
			 * programming full range right before the last inserted frame.
			 * However, we do not want to program the full freesync range
			 * when fixed refresh is active, because we only program
			 * that logic once and this will override it.
			 */
			if (core_freesync->map[map_index].user_enable.
				enable_for_gaming == true &&
				state->fullscreen == true &&
				state->fixed_refresh.fixed_active == false) {
				/* Enable freesync */

				v_total_min = state->freesync_range.vmin;
				v_total_max = state->freesync_range.vmax;

				/* Update the freesync context for the stream */
				update_stream_freesync_context(core_freesync,
						streams[stream_idx]);

				core_freesync->dc->stream_funcs.
				adjust_vmin_vmax(core_freesync->dc, streams,
						num_streams, v_total_min,
						v_total_max);

				return true;

			} else if (core_freesync->map[map_index].user_enable.
				enable_for_video && state->video == true) {
				/* Enable 48Hz feature */

				calc_v_total_from_duration(streams[stream_idx],
					state->time.update_duration_in_ns,
					&v_total_nominal);

				/* Program only if v_total_nominal is in range*/
				if (v_total_nominal >=
					streams[stream_idx]->timing.v_total) {

					/* Update the freesync context for
					 * the stream
					 */
					update_stream_freesync_context(
						core_freesync,
						streams[stream_idx]);

					core_freesync->dc->stream_funcs.
					adjust_vmin_vmax(
						core_freesync->dc, streams,
						num_streams, v_total_nominal,
						v_total_nominal);
				}
				return true;

			} else {
				/* Disable freesync */
				v_total_nominal = streams[stream_idx]->
					timing.v_total;

				/* Update the freesync context for
				 * the stream
				 */
				update_stream_freesync_context(
					core_freesync,
					streams[stream_idx]);

				core_freesync->dc->stream_funcs.
						adjust_vmin_vmax(
						core_freesync->dc, streams,
						num_streams, v_total_nominal,
						v_total_nominal);

				/* Reset the cached variables */
				reset_freesync_state_variables(state);

				return true;
			}
		} else {
			/* Disable freesync */
			v_total_nominal = streams[stream_idx]->
				timing.v_total;
			/*
			 * we have to reset drr always even sink does
			 * not support freesync because a former stream has
			 * be programmed
			 */
			core_freesync->dc->stream_funcs.
					adjust_vmin_vmax(
					core_freesync->dc, streams,
					num_streams, v_total_nominal,
					v_total_nominal);
			/* Reset the cached variables */
			reset_freesync_state_variables(state);
		}

	}

	return false;
}

static void set_static_ramp_variables(struct core_freesync *core_freesync,
		unsigned int index, bool enable_static_screen)
{
	unsigned int frame_duration = 0;
	unsigned int nominal_refresh_rate = core_freesync->map[index].state.
			nominal_refresh_rate_in_micro_hz;
	unsigned int min_refresh_rate= core_freesync->map[index].caps->
			min_refresh_in_micro_hz;
	struct gradual_static_ramp *static_ramp_variables =
			&core_freesync->map[index].state.static_ramp;

	/* If we are ENABLING static screen, refresh rate should go DOWN.
	 * If we are DISABLING static screen, refresh rate should go UP.
	 */
	if (enable_static_screen)
		static_ramp_variables->ramp_direction_is_up = false;
	else
		static_ramp_variables->ramp_direction_is_up = true;

	/* If ramp is not active, set initial frame duration depending on
	 * whether we are enabling/disabling static screen mode. If the ramp is
	 * already active, ramp should continue in the opposite direction
	 * starting with the current frame duration
	 */
	if (!static_ramp_variables->ramp_is_active) {
		if (enable_static_screen == true) {
			/* Going to lower refresh rate, so start from max
			 * refresh rate (min frame duration)
			 */
			frame_duration = ((unsigned int) (div64_u64(
				(1000000000ULL * 1000000),
				nominal_refresh_rate)));
		} else {
			/* Going to higher refresh rate, so start from min
			 * refresh rate (max frame duration)
			 */
			frame_duration = ((unsigned int) (div64_u64(
				(1000000000ULL * 1000000),
				min_refresh_rate)));
		}
		static_ramp_variables->
			ramp_current_frame_duration_in_ns = frame_duration;

		static_ramp_variables->ramp_is_active = true;
	}
}

void mod_freesync_handle_v_update(struct mod_freesync *mod_freesync,
		struct dc_stream_state **streams, int num_streams)
{
	unsigned int index, v_total, inserted_frame_v_total = 0;
	unsigned int min_frame_duration_in_ns, vmax, vmin = 0;
	struct freesync_state *state;
	struct core_freesync *core_freesync = NULL;
	struct dc_static_screen_events triggers = {0};

	if (mod_freesync == NULL)
		return;

	core_freesync = MOD_FREESYNC_TO_CORE(mod_freesync);

	if (core_freesync->num_entities == 0)
		return;

	index = map_index_from_stream(core_freesync,
		streams[0]);

	if (core_freesync->map[index].caps->supported == false)
		return;

	state = &core_freesync->map[index].state;

	/* Below the Range Logic */

	/* Only execute if in fullscreen mode */
	if (state->fullscreen == true &&
		core_freesync->map[index].user_enable.enable_for_gaming &&
		core_freesync->map[index].caps->btr_supported &&
		state->btr.btr_active) {

		/* TODO: pass in flag for Pre-DCE12 ASIC
		 * in order for frame variable duration to take affect,
		 * it needs to be done one VSYNC early, which is at
		 * frameCounter == 1.
		 * For DCE12 and newer updates to V_TOTAL_MIN/MAX
		 * will take affect on current frame
		 */
		if (state->btr.frames_to_insert == state->btr.frame_counter) {

			min_frame_duration_in_ns = ((unsigned int) (div64_u64(
					(1000000000ULL * 1000000),
					state->nominal_refresh_rate_in_micro_hz)));

			vmin = state->freesync_range.vmin;

			inserted_frame_v_total = vmin;

			if (min_frame_duration_in_ns / 1000)
				inserted_frame_v_total =
					state->btr.inserted_frame_duration_in_us *
					vmin / (min_frame_duration_in_ns / 1000);

			/* Set length of inserted frames as v_total_max*/
			vmax = inserted_frame_v_total;
			vmin = inserted_frame_v_total;

			/* Program V_TOTAL */
			core_freesync->dc->stream_funcs.adjust_vmin_vmax(
				core_freesync->dc, streams,
				num_streams, vmin, vmax);
		}

		if (state->btr.frame_counter > 0)
			state->btr.frame_counter--;

		/* Restore FreeSync */
		if (state->btr.frame_counter == 0)
			set_freesync_on_streams(core_freesync, streams, num_streams);
	}

	/* If in fullscreen freesync mode or in video, do not program
	 * static screen ramp values
	 */
	if (state->fullscreen == true || state->video == true) {

		state->static_ramp.ramp_is_active = false;

		return;
	}

	/* Gradual Static Screen Ramping Logic */

	/* Execute if ramp is active and user enabled freesync static screen*/
	if (state->static_ramp.ramp_is_active &&
		core_freesync->map[index].user_enable.enable_for_static) {

		calc_v_total_for_static_ramp(core_freesync, streams[0],
				index, &v_total);

		/* Update the freesync context for the stream */
		update_stream_freesync_context(core_freesync, streams[0]);

		/* Program static screen ramp values */
		core_freesync->dc->stream_funcs.adjust_vmin_vmax(
					core_freesync->dc, streams,
					num_streams, v_total,
					v_total);

		triggers.overlay_update = true;
		triggers.surface_update = true;

		core_freesync->dc->stream_funcs.set_static_screen_events(
					core_freesync->dc, streams,	num_streams,
					&triggers);
	}
}

void mod_freesync_update_state(struct mod_freesync *mod_freesync,
		struct dc_stream_state **streams, int num_streams,
		struct mod_freesync_params *freesync_params)
{
	bool freesync_program_required = false;
	unsigned int stream_index;
	struct freesync_state *state;
	struct core_freesync *core_freesync = NULL;
	struct dc_static_screen_events triggers = {0};

	if (mod_freesync == NULL)
		return;

	core_freesync = MOD_FREESYNC_TO_CORE(mod_freesync);

	if (core_freesync->num_entities == 0)
		return;

	for(stream_index = 0; stream_index < num_streams; stream_index++) {

		unsigned int map_index = map_index_from_stream(core_freesync,
				streams[stream_index]);

		bool is_embedded = dc_is_embedded_signal(
				streams[stream_index]->sink->sink_signal);

		struct freesync_registry_options *opts = &core_freesync->opts;

		state = &core_freesync->map[map_index].state;

		switch (freesync_params->state){
		case FREESYNC_STATE_FULLSCREEN:
			state->fullscreen = freesync_params->enable;
			freesync_program_required = true;
			state->windowed_fullscreen =
					freesync_params->windowed_fullscreen;
			break;
		case FREESYNC_STATE_STATIC_SCREEN:
			/* Static screen ramp is disabled by default, but can
			 * be enabled through regkey.
			 */
			if ((is_embedded && opts->drr_internal_supported) ||
				(!is_embedded && opts->drr_external_supported))

				if (state->static_screen !=
						freesync_params->enable) {

					/* Change the state flag */
					state->static_screen =
							freesync_params->enable;

					/* Update static screen ramp */
					set_static_ramp_variables(core_freesync,
						map_index,
						freesync_params->enable);
				}
			/* We program the ramp starting next VUpdate */
			break;
		case FREESYNC_STATE_VIDEO:
			/* Change core variables only if there is a change*/
			if(freesync_params->update_duration_in_ns !=
				state->time.update_duration_in_ns) {

				state->video = freesync_params->enable;
				state->time.update_duration_in_ns =
					freesync_params->update_duration_in_ns;

				freesync_program_required = true;
			}
			break;
		case FREESYNC_STATE_NONE:
			/* handle here to avoid warning */
			break;
		}
	}

	/* Update mask */
	triggers.overlay_update = true;
	triggers.surface_update = true;

	core_freesync->dc->stream_funcs.set_static_screen_events(
		core_freesync->dc, streams, num_streams,
		&triggers);

	if (freesync_program_required)
		/* Program freesync according to current state*/
		set_freesync_on_streams(core_freesync, streams, num_streams);
}


bool mod_freesync_get_state(struct mod_freesync *mod_freesync,
		struct dc_stream_state *stream,
		struct mod_freesync_params *freesync_params)
{
	unsigned int index = 0;
	struct core_freesync *core_freesync = NULL;

	if (mod_freesync == NULL)
		return false;

	core_freesync = MOD_FREESYNC_TO_CORE(mod_freesync);
	index = map_index_from_stream(core_freesync, stream);

	if (core_freesync->map[index].state.fullscreen) {
		freesync_params->state = FREESYNC_STATE_FULLSCREEN;
		freesync_params->enable = true;
	} else if (core_freesync->map[index].state.static_screen) {
		freesync_params->state = FREESYNC_STATE_STATIC_SCREEN;
		freesync_params->enable = true;
	} else if (core_freesync->map[index].state.video) {
		freesync_params->state = FREESYNC_STATE_VIDEO;
		freesync_params->enable = true;
	} else {
		freesync_params->state = FREESYNC_STATE_NONE;
		freesync_params->enable = false;
	}

	freesync_params->update_duration_in_ns =
		core_freesync->map[index].state.time.update_duration_in_ns;

	freesync_params->windowed_fullscreen =
			core_freesync->map[index].state.windowed_fullscreen;

	return true;
}

bool mod_freesync_set_user_enable(struct mod_freesync *mod_freesync,
		struct dc_stream_state **streams, int num_streams,
		struct mod_freesync_user_enable *user_enable)
{
	unsigned int stream_index, map_index;
	int persistent_data = 0;
	struct persistent_data_flag flag;
	struct dc  *dc = NULL;
	struct core_freesync *core_freesync = NULL;

	if (mod_freesync == NULL)
		return false;

	core_freesync = MOD_FREESYNC_TO_CORE(mod_freesync);
	dc = core_freesync->dc;

	flag.save_per_edid = true;
	flag.save_per_link = false;

	for(stream_index = 0; stream_index < num_streams;
			stream_index++){

		map_index = map_index_from_stream(core_freesync,
				streams[stream_index]);

		core_freesync->map[map_index].user_enable = *user_enable;

		/* Write persistent data in registry*/
		if (core_freesync->map[map_index].user_enable.
				enable_for_gaming)
			persistent_data = persistent_data | 1;
		if (core_freesync->map[map_index].user_enable.
				enable_for_static)
			persistent_data = persistent_data | 2;
		if (core_freesync->map[map_index].user_enable.
				enable_for_video)
			persistent_data = persistent_data | 4;

		dm_write_persistent_data(dc->ctx,
					streams[stream_index]->sink,
					FREESYNC_REGISTRY_NAME,
					"userenable",
					&persistent_data,
					sizeof(int),
					&flag);
	}

	set_freesync_on_streams(core_freesync, streams, num_streams);

	return true;
}

bool mod_freesync_get_user_enable(struct mod_freesync *mod_freesync,
		struct dc_stream_state *stream,
		struct mod_freesync_user_enable *user_enable)
{
	unsigned int index = 0;
	struct core_freesync *core_freesync = NULL;

	if (mod_freesync == NULL)
		return false;

	core_freesync = MOD_FREESYNC_TO_CORE(mod_freesync);
	index = map_index_from_stream(core_freesync, stream);

	*user_enable = core_freesync->map[index].user_enable;

	return true;
}

bool mod_freesync_get_static_ramp_active(struct mod_freesync *mod_freesync,
		struct dc_stream_state *stream,
		bool *is_ramp_active)
{
	unsigned int index = 0;
	struct core_freesync *core_freesync = NULL;

	if (mod_freesync == NULL)
		return false;

	core_freesync = MOD_FREESYNC_TO_CORE(mod_freesync);
	index = map_index_from_stream(core_freesync, stream);

	*is_ramp_active =
		core_freesync->map[index].state.static_ramp.ramp_is_active;

	return true;
}

bool mod_freesync_override_min_max(struct mod_freesync *mod_freesync,
		struct dc_stream_state *streams,
		unsigned int min_refresh,
		unsigned int max_refresh,
		struct mod_freesync_caps *caps)
{
	unsigned int index = 0;
	struct core_freesync *core_freesync;
	struct freesync_state *state;

	if (mod_freesync == NULL)
		return false;

	core_freesync = MOD_FREESYNC_TO_CORE(mod_freesync);
	index = map_index_from_stream(core_freesync, streams);
	state = &core_freesync->map[index].state;

	if (max_refresh == 0)
		max_refresh = state->nominal_refresh_rate_in_micro_hz;

	if (min_refresh == 0) {
		/* Restore defaults */
		calc_freesync_range(core_freesync, streams, state,
			core_freesync->map[index].caps->
			min_refresh_in_micro_hz,
			state->nominal_refresh_rate_in_micro_hz);
	} else {
		calc_freesync_range(core_freesync, streams,
				state,
				min_refresh,
				max_refresh);

		/* Program vtotal min/max */
		core_freesync->dc->stream_funcs.adjust_vmin_vmax(
			core_freesync->dc, &streams, 1,
			state->freesync_range.vmin,
			state->freesync_range.vmax);
	}

	if (min_refresh != 0 &&
			dc_is_embedded_signal(streams->sink->sink_signal) &&
			(max_refresh - min_refresh >= 10000000)) {
		caps->supported = true;
		caps->min_refresh_in_micro_hz = min_refresh;
		caps->max_refresh_in_micro_hz = max_refresh;
	}

	/* Update the stream */
	update_stream(core_freesync, streams);

	return true;
}

bool mod_freesync_get_min_max(struct mod_freesync *mod_freesync,
		struct dc_stream_state *stream,
		unsigned int *min_refresh,
		unsigned int *max_refresh)
{
	unsigned int index = 0;
	struct core_freesync *core_freesync = NULL;

	if (mod_freesync == NULL)
		return false;

	core_freesync = MOD_FREESYNC_TO_CORE(mod_freesync);
	index = map_index_from_stream(core_freesync, stream);

	*min_refresh =
		core_freesync->map[index].state.freesync_range.min_refresh;
	*max_refresh =
		core_freesync->map[index].state.freesync_range.max_refresh;

	return true;
}

bool mod_freesync_get_vmin_vmax(struct mod_freesync *mod_freesync,
		struct dc_stream_state *stream,
		unsigned int *vmin,
		unsigned int *vmax)
{
	unsigned int index = 0;
	struct core_freesync *core_freesync = NULL;

	if (mod_freesync == NULL)
		return false;

	core_freesync = MOD_FREESYNC_TO_CORE(mod_freesync);
	index = map_index_from_stream(core_freesync, stream);

	*vmin =
		core_freesync->map[index].state.freesync_range.vmin;
	*vmax =
		core_freesync->map[index].state.freesync_range.vmax;

	return true;
}

bool mod_freesync_get_v_position(struct mod_freesync *mod_freesync,
		struct dc_stream_state *stream,
		unsigned int *nom_v_pos,
		unsigned int *v_pos)
{
	unsigned int index = 0;
	struct core_freesync *core_freesync = NULL;
	struct crtc_position position;

	if (mod_freesync == NULL)
		return false;

	core_freesync = MOD_FREESYNC_TO_CORE(mod_freesync);
	index = map_index_from_stream(core_freesync, stream);

	if (core_freesync->dc->stream_funcs.get_crtc_position(
			core_freesync->dc, &stream, 1,
			&position.vertical_count, &position.nominal_vcount)) {

		*nom_v_pos = position.nominal_vcount;
		*v_pos = position.vertical_count;

		return true;
	}

	return false;
}

void mod_freesync_notify_mode_change(struct mod_freesync *mod_freesync,
		struct dc_stream_state **streams, int num_streams)
{
	unsigned int stream_index, map_index;
	struct freesync_state *state;
	struct core_freesync *core_freesync = NULL;
	struct dc_static_screen_events triggers = {0};
	unsigned long long temp = 0;

	if (mod_freesync == NULL)
		return;

	core_freesync = MOD_FREESYNC_TO_CORE(mod_freesync);

	for (stream_index = 0; stream_index < num_streams; stream_index++) {
		map_index = map_index_from_stream(core_freesync,
				streams[stream_index]);

		state = &core_freesync->map[map_index].state;

		/* Update the field rate for new timing */
		temp = streams[stream_index]->timing.pix_clk_khz;
		temp *= 1000ULL * 1000ULL * 1000ULL;
		temp = div_u64(temp,
				streams[stream_index]->timing.h_total);
		temp = div_u64(temp,
				streams[stream_index]->timing.v_total);
		state->nominal_refresh_rate_in_micro_hz =
				(unsigned int) temp;

		if (core_freesync->map[map_index].caps->supported) {

			/* Update the stream */
			update_stream(core_freesync, streams[stream_index]);

			/* Calculate vmin/vmax and refresh rate for
			 * current mode
			 */
			calc_freesync_range(core_freesync, *streams, state,
				core_freesync->map[map_index].caps->
				min_refresh_in_micro_hz,
				state->nominal_refresh_rate_in_micro_hz);

			/* Update mask */
			triggers.overlay_update = true;
			triggers.surface_update = true;

			core_freesync->dc->stream_funcs.set_static_screen_events(
				core_freesync->dc, streams, num_streams,
				&triggers);
		}
	}

	/* Program freesync according to current state*/
	set_freesync_on_streams(core_freesync, streams, num_streams);
}

/* Add the timestamps to the cache and determine whether BTR programming
 * is required, depending on the times calculated
 */
static void update_timestamps(struct core_freesync *core_freesync,
		const struct dc_stream_state *stream, unsigned int map_index,
		unsigned int last_render_time_in_us)
{
	struct freesync_state *state = &core_freesync->map[map_index].state;

	state->time.render_times[state->time.render_times_index] =
			last_render_time_in_us;
	state->time.render_times_index++;

	if (state->time.render_times_index >= RENDER_TIMES_MAX_COUNT)
		state->time.render_times_index = 0;

	if (last_render_time_in_us + BTR_EXIT_MARGIN <
		state->time.max_render_time_in_us) {

		/* Exit Below the Range */
		if (state->btr.btr_active) {

			state->btr.program_btr = true;
			state->btr.btr_active = false;
			state->btr.frame_counter = 0;

		/* Exit Fixed Refresh mode */
		} else if (state->fixed_refresh.fixed_active) {

			state->fixed_refresh.frame_counter++;

			if (state->fixed_refresh.frame_counter >
					FIXED_REFRESH_EXIT_FRAME_COUNT) {
				state->fixed_refresh.frame_counter = 0;
				state->fixed_refresh.program_fixed = true;
				state->fixed_refresh.fixed_active = false;
			}
		}

	} else if (last_render_time_in_us > state->time.max_render_time_in_us) {

		/* Enter Below the Range */
		if (!state->btr.btr_active &&
			core_freesync->map[map_index].caps->btr_supported) {

			state->btr.program_btr = true;
			state->btr.btr_active = true;

		/* Enter Fixed Refresh mode */
		} else if (!state->fixed_refresh.fixed_active &&
			!core_freesync->map[map_index].caps->btr_supported) {

			state->fixed_refresh.frame_counter++;

			if (state->fixed_refresh.frame_counter >
					FIXED_REFRESH_ENTER_FRAME_COUNT) {
				state->fixed_refresh.frame_counter = 0;
				state->fixed_refresh.program_fixed = true;
				state->fixed_refresh.fixed_active = true;
			}
		}
	}

	/* When Below the Range is active, must react on every frame */
	if (state->btr.btr_active)
		state->btr.program_btr = true;
}

static void apply_below_the_range(struct core_freesync *core_freesync,
		struct dc_stream_state *stream, unsigned int map_index,
		unsigned int last_render_time_in_us)
{
	unsigned int inserted_frame_duration_in_us = 0;
	unsigned int mid_point_frames_ceil = 0;
	unsigned int mid_point_frames_floor = 0;
	unsigned int frame_time_in_us = 0;
	unsigned int delta_from_mid_point_in_us_1 = 0xFFFFFFFF;
	unsigned int delta_from_mid_point_in_us_2 = 0xFFFFFFFF;
	unsigned int frames_to_insert = 0;
	unsigned int min_frame_duration_in_ns = 0;
	struct freesync_state *state = &core_freesync->map[map_index].state;

	if (!state->btr.program_btr)
		return;

	state->btr.program_btr = false;

	min_frame_duration_in_ns = ((unsigned int) (div64_u64(
		(1000000000ULL * 1000000),
		state->nominal_refresh_rate_in_micro_hz)));

	/* Program BTR */

	/* BTR set to "not active" so disengage */
	if (!state->btr.btr_active)

		/* Restore FreeSync */
		set_freesync_on_streams(core_freesync, &stream, 1);

	/* BTR set to "active" so engage */
	else {

		/* Calculate number of midPoint frames that could fit within
		 * the render time interval- take ceil of this value
		 */
		mid_point_frames_ceil = (last_render_time_in_us +
			state->btr.mid_point_in_us- 1) /
			state->btr.mid_point_in_us;

		if (mid_point_frames_ceil > 0) {

			frame_time_in_us = last_render_time_in_us /
				mid_point_frames_ceil;
			delta_from_mid_point_in_us_1 =
				(state->btr.mid_point_in_us >
				frame_time_in_us) ?
				(state->btr.mid_point_in_us - frame_time_in_us):
				(frame_time_in_us - state->btr.mid_point_in_us);
		}

		/* Calculate number of midPoint frames that could fit within
		 * the render time interval- take floor of this value
		 */
		mid_point_frames_floor = last_render_time_in_us /
			state->btr.mid_point_in_us;

		if (mid_point_frames_floor > 0) {

			frame_time_in_us = last_render_time_in_us /
				mid_point_frames_floor;
			delta_from_mid_point_in_us_2 =
				(state->btr.mid_point_in_us >
				frame_time_in_us) ?
				(state->btr.mid_point_in_us - frame_time_in_us):
				(frame_time_in_us - state->btr.mid_point_in_us);
		}

		/* Choose number of frames to insert based on how close it
		 * can get to the mid point of the variable range.
		 */
		if (delta_from_mid_point_in_us_1 < delta_from_mid_point_in_us_2)
			frames_to_insert = mid_point_frames_ceil;
		else
			frames_to_insert = mid_point_frames_floor;

		/* Either we've calculated the number of frames to insert,
		 * or we need to insert min duration frames
		 */
		if (frames_to_insert > 0)
			inserted_frame_duration_in_us = last_render_time_in_us /
							frames_to_insert;

		if (inserted_frame_duration_in_us <
			state->time.min_render_time_in_us)

			inserted_frame_duration_in_us =
				state->time.min_render_time_in_us;

		/* Cache the calculated variables */
		state->btr.inserted_frame_duration_in_us =
			inserted_frame_duration_in_us;
		state->btr.frames_to_insert = frames_to_insert;
		state->btr.frame_counter = frames_to_insert;

	}
}

static void apply_fixed_refresh(struct core_freesync *core_freesync,
		struct dc_stream_state *stream, unsigned int map_index)
{
	unsigned int vmin = 0, vmax = 0;
	struct freesync_state *state = &core_freesync->map[map_index].state;

	if (!state->fixed_refresh.program_fixed)
		return;

	state->fixed_refresh.program_fixed = false;

	/* Program Fixed Refresh */

	/* Fixed Refresh set to "not active" so disengage */
	if (!state->fixed_refresh.fixed_active) {
		set_freesync_on_streams(core_freesync, &stream, 1);

	/* Fixed Refresh set to "active" so engage (fix to max) */
	} else {

		vmin = state->freesync_range.vmin;

		vmax = vmin;

		core_freesync->dc->stream_funcs.adjust_vmin_vmax(
				core_freesync->dc, &stream,
				1, vmin,
				vmax);
	}
}

void mod_freesync_pre_update_plane_addresses(struct mod_freesync *mod_freesync,
		struct dc_stream_state **streams, int num_streams,
		unsigned int curr_time_stamp_in_us)
{
	unsigned int stream_index, map_index, last_render_time_in_us = 0;
	struct core_freesync *core_freesync = NULL;

	if (mod_freesync == NULL)
		return;

	core_freesync = MOD_FREESYNC_TO_CORE(mod_freesync);

	for (stream_index = 0; stream_index < num_streams; stream_index++) {

		map_index = map_index_from_stream(core_freesync,
						streams[stream_index]);

		if (core_freesync->map[map_index].caps->supported) {

			last_render_time_in_us = curr_time_stamp_in_us -
					core_freesync->map[map_index].state.time.
					prev_time_stamp_in_us;

			/* Add the timestamps to the cache and determine
			 * whether BTR program is required
			 */
			update_timestamps(core_freesync, streams[stream_index],
					map_index, last_render_time_in_us);

			if (core_freesync->map[map_index].state.fullscreen &&
				core_freesync->map[map_index].user_enable.
				enable_for_gaming) {

				if (core_freesync->map[map_index].caps->btr_supported) {

					apply_below_the_range(core_freesync,
						streams[stream_index], map_index,
						last_render_time_in_us);
				} else {
					apply_fixed_refresh(core_freesync,
						streams[stream_index], map_index);
				}
			}

			core_freesync->map[map_index].state.time.
				prev_time_stamp_in_us = curr_time_stamp_in_us;
		}

	}
}