/*
 * 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 <linux/slab.h>

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

#define MOD_FREESYNC_MAX_CONCURRENT_STREAMS  32

#define MIN_REFRESH_RANGE 10
/* 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 10
/* Threshold to exit/exit BTR (to avoid frequent enter-exits at the lower limit) */
#define BTR_MAX_MARGIN 2500
/* Threshold to change BTR multiplier (to avoid frequent changes) */
#define BTR_DRIFT_MARGIN 2000
/* Threshold to exit fixed refresh rate */
#define FIXED_REFRESH_EXIT_MARGIN_IN_HZ 1
/* Number of consecutive frames to check before entering/exiting fixed refresh */
#define FIXED_REFRESH_ENTER_FRAME_COUNT 5
#define FIXED_REFRESH_EXIT_FRAME_COUNT 10

struct core_freesync {
        struct mod_freesync public;
        struct dc *dc;
};

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

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

        if (core_freesync == NULL)
                goto fail_alloc_context;

        if (dc == NULL)
                goto fail_construct;

        core_freesync->dc = dc;
        return &core_freesync->public;

fail_construct:
        kfree(core_freesync);

fail_alloc_context:
        return NULL;
}

void mod_freesync_destroy(struct mod_freesync *mod_freesync)
{
        struct core_freesync *core_freesync = NULL;
        if (mod_freesync == NULL)
                return;
        core_freesync = MOD_FREESYNC_TO_CORE(mod_freesync);
        kfree(core_freesync);
}

#if 0 /* Unused currently */
static unsigned int calc_refresh_in_uhz_from_duration(
                unsigned int duration_in_ns)
{
        unsigned int refresh_in_uhz =
                        ((unsigned int)(div64_u64((1000000000ULL * 1000000),
                                        duration_in_ns)));
        return refresh_in_uhz;
}
#endif

static unsigned int calc_duration_in_us_from_refresh_in_uhz(
                unsigned int refresh_in_uhz)
{
        unsigned int duration_in_us =
                        ((unsigned int)(div64_u64((1000000000ULL * 1000),
                                        refresh_in_uhz)));
        return duration_in_us;
}

static unsigned int calc_duration_in_us_from_v_total(
                const struct dc_stream_state *stream,
                const struct mod_vrr_params *in_vrr,
                unsigned int v_total)
{
        unsigned int duration_in_us =
                        (unsigned int)(div64_u64(((unsigned long long)(v_total)
                                * 10000) * stream->timing.h_total,
                                        stream->timing.pix_clk_100hz));

        return duration_in_us;
}

static unsigned int calc_v_total_from_refresh(
                const struct dc_stream_state *stream,
                unsigned int refresh_in_uhz)
{
        unsigned int v_total;
        unsigned int frame_duration_in_ns;

        frame_duration_in_ns =
                        ((unsigned int)(div64_u64((1000000000ULL * 1000000),
                                        refresh_in_uhz)));

        v_total = div64_u64(div64_u64(((unsigned long long)(
                        frame_duration_in_ns) * (stream->timing.pix_clk_100hz / 10)),
                        stream->timing.h_total), 1000000);

        /* v_total cannot be less than nominal */
        if (v_total < stream->timing.v_total) {
                ASSERT(v_total < stream->timing.v_total);
                v_total = stream->timing.v_total;
        }

        return v_total;
}

static unsigned int calc_v_total_from_duration(
                const struct dc_stream_state *stream,
                const struct mod_vrr_params *vrr,
                unsigned int duration_in_us)
{
        unsigned int v_total = 0;

        if (duration_in_us < vrr->min_duration_in_us)
                duration_in_us = vrr->min_duration_in_us;

        if (duration_in_us > vrr->max_duration_in_us)
                duration_in_us = vrr->max_duration_in_us;

        v_total = div64_u64(div64_u64(((unsigned long long)(
                                duration_in_us) * (stream->timing.pix_clk_100hz / 10)),
                                stream->timing.h_total), 1000);

        /* v_total cannot be less than nominal */
        if (v_total < stream->timing.v_total) {
                ASSERT(v_total < stream->timing.v_total);
                v_total = stream->timing.v_total;
        }

        return v_total;
}

static void update_v_total_for_static_ramp(
                struct core_freesync *core_freesync,
                const struct dc_stream_state *stream,
                struct mod_vrr_params *in_out_vrr)
{
        unsigned int v_total = 0;
        unsigned int current_duration_in_us =
                        calc_duration_in_us_from_v_total(
                                stream, in_out_vrr,
                                in_out_vrr->adjust.v_total_max);
        unsigned int target_duration_in_us =
                        calc_duration_in_us_from_refresh_in_uhz(
                                in_out_vrr->fixed.target_refresh_in_uhz);
        bool ramp_direction_is_up = (current_duration_in_us >
                                target_duration_in_us) ? true : false;

        /* Calculate 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) *
                current_duration_in_us),
                1000000)));

        /* Calculate delta between new and current frame duration in us */
        unsigned int frame_duration_delta = div64_u64(((unsigned long long)(
                current_duration_in_us) *
                (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) * current_duration_in_us), 16666);

        /* Going to a higher refresh rate (lower frame duration) */
        if (ramp_direction_is_up) {
                /* Reduce frame duration */
                current_duration_in_us -= ramp_rate_interpolated;

                /* Adjust for frame duration below min */
                if (current_duration_in_us <= target_duration_in_us) {
                        in_out_vrr->fixed.ramping_active = false;
                        in_out_vrr->fixed.ramping_done = true;
                        current_duration_in_us =
                                calc_duration_in_us_from_refresh_in_uhz(
                                in_out_vrr->fixed.target_refresh_in_uhz);
                }
        /* Going to a lower refresh rate (larger frame duration) */
        } else {
                /* Increase frame duration */
                current_duration_in_us += ramp_rate_interpolated;

                /* Adjust for frame duration above max */
                if (current_duration_in_us >= target_duration_in_us) {
                        in_out_vrr->fixed.ramping_active = false;
                        in_out_vrr->fixed.ramping_done = true;
                        current_duration_in_us =
                                calc_duration_in_us_from_refresh_in_uhz(
                                in_out_vrr->fixed.target_refresh_in_uhz);
                }
        }

        v_total = div64_u64(div64_u64(((unsigned long long)(
                        current_duration_in_us) * (stream->timing.pix_clk_100hz / 10)),
                                stream->timing.h_total), 1000);

        /* v_total cannot be less than nominal */
        if (v_total < stream->timing.v_total)
                v_total = stream->timing.v_total;

        in_out_vrr->adjust.v_total_min = v_total;
        in_out_vrr->adjust.v_total_max = v_total;
}

static void apply_below_the_range(struct core_freesync *core_freesync,
                const struct dc_stream_state *stream,
                unsigned int last_render_time_in_us,
                struct mod_vrr_params *in_out_vrr)
{
        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 delta_from_mid_point_delta_in_us;
        unsigned int max_render_time_in_us =
                        in_out_vrr->max_duration_in_us - in_out_vrr->btr.margin_in_us;

        /* Program BTR */
        if ((last_render_time_in_us + in_out_vrr->btr.margin_in_us / 2) < max_render_time_in_us) {
                /* Exit Below the Range */
                if (in_out_vrr->btr.btr_active) {
                        in_out_vrr->btr.frame_counter = 0;
                        in_out_vrr->btr.btr_active = false;
                }
        } else if (last_render_time_in_us > (max_render_time_in_us + in_out_vrr->btr.margin_in_us / 2)) {
                /* Enter Below the Range */
                if (!in_out_vrr->btr.btr_active) {
                        in_out_vrr->btr.btr_active = true;
                }
        }

        /* BTR set to "not active" so disengage */
        if (!in_out_vrr->btr.btr_active) {
                in_out_vrr->btr.inserted_duration_in_us = 0;
                in_out_vrr->btr.frames_to_insert = 0;
                in_out_vrr->btr.frame_counter = 0;

                /* Restore FreeSync */
                in_out_vrr->adjust.v_total_min =
                        calc_v_total_from_refresh(stream,
                                in_out_vrr->max_refresh_in_uhz);
                in_out_vrr->adjust.v_total_max =
                        calc_v_total_from_refresh(stream,
                                in_out_vrr->min_refresh_in_uhz);
        /* 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 +
                                in_out_vrr->btr.mid_point_in_us - 1) /
                                        in_out_vrr->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 =
                                (in_out_vrr->btr.mid_point_in_us >
                                frame_time_in_us) ?
                                (in_out_vrr->btr.mid_point_in_us - frame_time_in_us) :
                                (frame_time_in_us - in_out_vrr->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 /
                                in_out_vrr->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 =
                                (in_out_vrr->btr.mid_point_in_us >
                                frame_time_in_us) ?
                                (in_out_vrr->btr.mid_point_in_us - frame_time_in_us) :
                                (frame_time_in_us - in_out_vrr->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.
                 *  - Delta for CEIL: delta_from_mid_point_in_us_1
                 *  - Delta for FLOOR: delta_from_mid_point_in_us_2
                 */
                if ((last_render_time_in_us / mid_point_frames_ceil) < in_out_vrr->min_duration_in_us) {
                        /* Check for out of range.
                         * If using CEIL produces a value that is out of range,
                         * then we are forced to use FLOOR.
                         */
                        frames_to_insert = mid_point_frames_floor;
                } else if (mid_point_frames_floor < 2) {
                        /* Check if FLOOR would result in non-LFC. In this case
                         * choose to use CEIL
                         */
                        frames_to_insert = mid_point_frames_ceil;
                } else if (delta_from_mid_point_in_us_1 < delta_from_mid_point_in_us_2) {
                        /* If choosing CEIL results in a frame duration that is
                         * closer to the mid point of the range.
                         * Choose CEIL
                         */
                        frames_to_insert = mid_point_frames_ceil;
                } else {
                        /* If choosing FLOOR results in a frame duration that is
                         * closer to the mid point of the range.
                         * Choose FLOOR
                         */
                        frames_to_insert = mid_point_frames_floor;
                }

                /* Prefer current frame multiplier when BTR is enabled unless it drifts
                 * too far from the midpoint
                 */
                if (delta_from_mid_point_in_us_1 < delta_from_mid_point_in_us_2) {
                        delta_from_mid_point_delta_in_us = delta_from_mid_point_in_us_2 -
                                        delta_from_mid_point_in_us_1;
                } else {
                        delta_from_mid_point_delta_in_us = delta_from_mid_point_in_us_1 -
                                        delta_from_mid_point_in_us_2;
                }
                if (in_out_vrr->btr.frames_to_insert != 0 &&
                                delta_from_mid_point_delta_in_us < BTR_DRIFT_MARGIN) {
                        if (((last_render_time_in_us / in_out_vrr->btr.frames_to_insert) <
                                        max_render_time_in_us) &&
                                ((last_render_time_in_us / in_out_vrr->btr.frames_to_insert) >
                                        in_out_vrr->min_duration_in_us))
                                frames_to_insert = in_out_vrr->btr.frames_to_insert;
                }

                /* Either we've calculated the number of frames to insert,
                 * or we need to insert min duration frames
                 */
                if (last_render_time_in_us / frames_to_insert <
                                in_out_vrr->min_duration_in_us){
                        frames_to_insert -= (frames_to_insert > 1) ?
                                        1 : 0;
                }

                if (frames_to_insert > 0)
                        inserted_frame_duration_in_us = last_render_time_in_us /
                                                        frames_to_insert;

                if (inserted_frame_duration_in_us < in_out_vrr->min_duration_in_us)
                        inserted_frame_duration_in_us = in_out_vrr->min_duration_in_us;

                /* Cache the calculated variables */
                in_out_vrr->btr.inserted_duration_in_us =
                        inserted_frame_duration_in_us;
                in_out_vrr->btr.frames_to_insert = frames_to_insert;
                in_out_vrr->btr.frame_counter = frames_to_insert;
        }
}

static void apply_fixed_refresh(struct core_freesync *core_freesync,
                const struct dc_stream_state *stream,
                unsigned int last_render_time_in_us,
                struct mod_vrr_params *in_out_vrr)
{
        bool update = false;
        unsigned int max_render_time_in_us = in_out_vrr->max_duration_in_us;

        /* Compute the exit refresh rate and exit frame duration */
        unsigned int exit_refresh_rate_in_milli_hz = ((1000000000/max_render_time_in_us)
                        + (1000*FIXED_REFRESH_EXIT_MARGIN_IN_HZ));
        unsigned int exit_frame_duration_in_us = 1000000000/exit_refresh_rate_in_milli_hz;

        if (last_render_time_in_us < exit_frame_duration_in_us) {
                /* Exit Fixed Refresh mode */
                if (in_out_vrr->fixed.fixed_active) {
                        in_out_vrr->fixed.frame_counter++;

                        if (in_out_vrr->fixed.frame_counter >
                                        FIXED_REFRESH_EXIT_FRAME_COUNT) {
                                in_out_vrr->fixed.frame_counter = 0;
                                in_out_vrr->fixed.fixed_active = false;
                                in_out_vrr->fixed.target_refresh_in_uhz = 0;
                                update = true;
                        }
                } else
                        in_out_vrr->fixed.frame_counter = 0;
        } else if (last_render_time_in_us > max_render_time_in_us) {
                /* Enter Fixed Refresh mode */
                if (!in_out_vrr->fixed.fixed_active) {
                        in_out_vrr->fixed.frame_counter++;

                        if (in_out_vrr->fixed.frame_counter >
                                        FIXED_REFRESH_ENTER_FRAME_COUNT) {
                                in_out_vrr->fixed.frame_counter = 0;
                                in_out_vrr->fixed.fixed_active = true;
                                in_out_vrr->fixed.target_refresh_in_uhz =
                                                in_out_vrr->max_refresh_in_uhz;
                                update = true;
                        }
                } else
                        in_out_vrr->fixed.frame_counter = 0;
        }

        if (update) {
                if (in_out_vrr->fixed.fixed_active) {
                        in_out_vrr->adjust.v_total_min =
                                calc_v_total_from_refresh(
                                stream, in_out_vrr->max_refresh_in_uhz);
                        in_out_vrr->adjust.v_total_max =
                                        in_out_vrr->adjust.v_total_min;
                } else {
                        in_out_vrr->adjust.v_total_min =
                                calc_v_total_from_refresh(stream,
                                        in_out_vrr->max_refresh_in_uhz);
                        in_out_vrr->adjust.v_total_max =
                                calc_v_total_from_refresh(stream,
                                        in_out_vrr->min_refresh_in_uhz);
                }
        }
}

static bool vrr_settings_require_update(struct core_freesync *core_freesync,
                struct mod_freesync_config *in_config,
                unsigned int min_refresh_in_uhz,
                unsigned int max_refresh_in_uhz,
                struct mod_vrr_params *in_vrr)
{
        if (in_vrr->state != in_config->state) {
                return true;
        } else if (in_vrr->state == VRR_STATE_ACTIVE_FIXED &&
                        in_vrr->fixed.target_refresh_in_uhz !=
                                        in_config->fixed_refresh_in_uhz) {
                return true;
        } else if (in_vrr->min_refresh_in_uhz != min_refresh_in_uhz) {
                return true;
        } else if (in_vrr->max_refresh_in_uhz != max_refresh_in_uhz) {
                return true;
        }

        return false;
}

bool mod_freesync_get_vmin_vmax(struct mod_freesync *mod_freesync,
                const struct dc_stream_state *stream,
                unsigned int *vmin,
                unsigned int *vmax)
{
        *vmin = stream->adjust.v_total_min;
        *vmax = stream->adjust.v_total_max;

        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)
{
        struct core_freesync *core_freesync = NULL;
        struct crtc_position position;

        if (mod_freesync == NULL)
                return false;

        core_freesync = MOD_FREESYNC_TO_CORE(mod_freesync);

        if (dc_stream_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;
}

static void build_vrr_infopacket_data_v1(const struct mod_vrr_params *vrr,
                struct dc_info_packet *infopacket)
{
        /* PB1 = 0x1A (24bit AMD IEEE OUI (0x00001A) - Byte 0) */
        infopacket->sb[1] = 0x1A;

        /* PB2 = 0x00 (24bit AMD IEEE OUI (0x00001A) - Byte 1) */
        infopacket->sb[2] = 0x00;

        /* PB3 = 0x00 (24bit AMD IEEE OUI (0x00001A) - Byte 2) */
        infopacket->sb[3] = 0x00;

        /* PB4 = Reserved */

        /* PB5 = Reserved */

        /* PB6 = [Bits 7:3 = Reserved] */

        /* PB6 = [Bit 0 = FreeSync Supported] */
        if (vrr->state != VRR_STATE_UNSUPPORTED)
                infopacket->sb[6] |= 0x01;

        /* PB6 = [Bit 1 = FreeSync Enabled] */
        if (vrr->state != VRR_STATE_DISABLED &&
                        vrr->state != VRR_STATE_UNSUPPORTED)
                infopacket->sb[6] |= 0x02;

        /* PB6 = [Bit 2 = FreeSync Active] */
        if (vrr->state == VRR_STATE_ACTIVE_VARIABLE ||
                        vrr->state == VRR_STATE_ACTIVE_FIXED)
                infopacket->sb[6] |= 0x04;

        // For v1 & 2 infoframes program nominal if non-fs mode, otherwise full range
        /* PB7 = FreeSync Minimum refresh rate (Hz) */
        if (vrr->state == VRR_STATE_ACTIVE_VARIABLE ||
                        vrr->state == VRR_STATE_ACTIVE_FIXED) {
                infopacket->sb[7] = (unsigned char)((vrr->min_refresh_in_uhz + 500000) / 1000000);
        } else {
                infopacket->sb[7] = (unsigned char)((vrr->max_refresh_in_uhz + 500000) / 1000000);
        }

        /* PB8 = FreeSync Maximum refresh rate (Hz)
         * Note: We should never go above the field rate of the mode timing set.
         */
        infopacket->sb[8] = (unsigned char)((vrr->max_refresh_in_uhz + 500000) / 1000000);

        /* FreeSync HDR */
        infopacket->sb[9] = 0;
        infopacket->sb[10] = 0;
}

static void build_vrr_infopacket_data_v3(const struct mod_vrr_params *vrr,
                struct dc_info_packet *infopacket)
{
        unsigned int min_refresh;
        unsigned int max_refresh;
        unsigned int fixed_refresh;
        unsigned int min_programmed;
        unsigned int max_programmed;

        /* PB1 = 0x1A (24bit AMD IEEE OUI (0x00001A) - Byte 0) */
        infopacket->sb[1] = 0x1A;

        /* PB2 = 0x00 (24bit AMD IEEE OUI (0x00001A) - Byte 1) */
        infopacket->sb[2] = 0x00;

        /* PB3 = 0x00 (24bit AMD IEEE OUI (0x00001A) - Byte 2) */
        infopacket->sb[3] = 0x00;

        /* PB4 = Reserved */

        /* PB5 = Reserved */

        /* PB6 = [Bits 7:3 = Reserved] */

        /* PB6 = [Bit 0 = FreeSync Supported] */
        if (vrr->state != VRR_STATE_UNSUPPORTED)
                infopacket->sb[6] |= 0x01;

        /* PB6 = [Bit 1 = FreeSync Enabled] */
        if (vrr->state != VRR_STATE_DISABLED &&
                        vrr->state != VRR_STATE_UNSUPPORTED)
                infopacket->sb[6] |= 0x02;

        /* PB6 = [Bit 2 = FreeSync Active] */
        if (vrr->state == VRR_STATE_ACTIVE_VARIABLE ||
                        vrr->state == VRR_STATE_ACTIVE_FIXED)
                infopacket->sb[6] |= 0x04;

        min_refresh = (vrr->min_refresh_in_uhz + 500000) / 1000000;
        max_refresh = (vrr->max_refresh_in_uhz + 500000) / 1000000;
        fixed_refresh = (vrr->fixed_refresh_in_uhz + 500000) / 1000000;

        min_programmed = (vrr->state == VRR_STATE_ACTIVE_FIXED) ? fixed_refresh :
                        (vrr->state == VRR_STATE_ACTIVE_VARIABLE) ? min_refresh :
                        (vrr->state == VRR_STATE_INACTIVE) ? min_refresh :
                        max_refresh; // Non-fs case, program nominal range

        max_programmed = (vrr->state == VRR_STATE_ACTIVE_FIXED) ? fixed_refresh :
                        (vrr->state == VRR_STATE_ACTIVE_VARIABLE) ? max_refresh :
                        max_refresh;// Non-fs case, program nominal range

        /* PB7 = FreeSync Minimum refresh rate (Hz) */
        infopacket->sb[7] = min_programmed & 0xFF;

        /* PB8 = FreeSync Maximum refresh rate (Hz) */
        infopacket->sb[8] = max_programmed & 0xFF;

        /* PB11 : MSB FreeSync Minimum refresh rate [Hz] - bits 9:8 */
        infopacket->sb[11] = (min_programmed >> 8) & 0x03;

        /* PB12 : MSB FreeSync Maximum refresh rate [Hz] - bits 9:8 */
        infopacket->sb[12] = (max_programmed >> 8) & 0x03;

        /* PB16 : Reserved bits 7:1, FixedRate bit 0 */
        infopacket->sb[16] = (vrr->state == VRR_STATE_ACTIVE_FIXED) ? 1 : 0;

        //FreeSync HDR
        infopacket->sb[9] = 0;
        infopacket->sb[10] = 0;
}

static void build_vrr_infopacket_fs2_data(enum color_transfer_func app_tf,
                struct dc_info_packet *infopacket)
{
        if (app_tf != TRANSFER_FUNC_UNKNOWN) {
                infopacket->valid = true;

                infopacket->sb[6] |= 0x08;  // PB6 = [Bit 3 = Native Color Active]

                if (app_tf == TRANSFER_FUNC_GAMMA_22) {
                        infopacket->sb[9] |= 0x04;  // PB6 = [Bit 2 = Gamma 2.2 EOTF Active]
                }
        }
}

static void build_vrr_infopacket_header_v1(enum signal_type signal,
                struct dc_info_packet *infopacket,
                unsigned int *payload_size)
{
        if (dc_is_hdmi_signal(signal)) {

                /* HEADER */

                /* HB0  = Packet Type = 0x83 (Source Product
                 *        Descriptor InfoFrame)
                 */
                infopacket->hb0 = DC_HDMI_INFOFRAME_TYPE_SPD;

                /* HB1  = Version = 0x01 */
                infopacket->hb1 = 0x01;

                /* HB2  = [Bits 7:5 = 0] [Bits 4:0 = Length = 0x08] */
                infopacket->hb2 = 0x08;

                *payload_size = 0x08;

        } else if (dc_is_dp_signal(signal)) {

                /* HEADER */

                /* HB0  = Secondary-data Packet ID = 0 - Only non-zero
                 *        when used to associate audio related info packets
                 */
                infopacket->hb0 = 0x00;

                /* HB1  = Packet Type = 0x83 (Source Product
                 *        Descriptor InfoFrame)
                 */
                infopacket->hb1 = DC_HDMI_INFOFRAME_TYPE_SPD;

                /* HB2  = [Bits 7:0 = Least significant eight bits -
                 *        For INFOFRAME, the value must be 1Bh]
                 */
                infopacket->hb2 = 0x1B;

                /* HB3  = [Bits 7:2 = INFOFRAME SDP Version Number = 0x1]
                 *        [Bits 1:0 = Most significant two bits = 0x00]
                 */
                infopacket->hb3 = 0x04;

                *payload_size = 0x1B;
        }
}

static void build_vrr_infopacket_header_v2(enum signal_type signal,
                struct dc_info_packet *infopacket,
                unsigned int *payload_size)
{
        if (dc_is_hdmi_signal(signal)) {

                /* HEADER */

                /* HB0  = Packet Type = 0x83 (Source Product
                 *        Descriptor InfoFrame)
                 */
                infopacket->hb0 = DC_HDMI_INFOFRAME_TYPE_SPD;

                /* HB1  = Version = 0x02 */
                infopacket->hb1 = 0x02;

                /* HB2  = [Bits 7:5 = 0] [Bits 4:0 = Length = 0x09] */
                infopacket->hb2 = 0x09;

                *payload_size = 0x0A;

        } else if (dc_is_dp_signal(signal)) {

                /* HEADER */

                /* HB0  = Secondary-data Packet ID = 0 - Only non-zero
                 *        when used to associate audio related info packets
                 */
                infopacket->hb0 = 0x00;

                /* HB1  = Packet Type = 0x83 (Source Product
                 *        Descriptor InfoFrame)
                 */
                infopacket->hb1 = DC_HDMI_INFOFRAME_TYPE_SPD;

                /* HB2  = [Bits 7:0 = Least significant eight bits -
                 *        For INFOFRAME, the value must be 1Bh]
                 */
                infopacket->hb2 = 0x1B;

                /* HB3  = [Bits 7:2 = INFOFRAME SDP Version Number = 0x2]
                 *        [Bits 1:0 = Most significant two bits = 0x00]
                 */
                infopacket->hb3 = 0x08;

                *payload_size = 0x1B;
        }
}

static void build_vrr_infopacket_header_v3(enum signal_type signal,
                struct dc_info_packet *infopacket,
                unsigned int *payload_size)
{
        unsigned char version;

        version = 3;
        if (dc_is_hdmi_signal(signal)) {

                /* HEADER */

                /* HB0  = Packet Type = 0x83 (Source Product
                 *        Descriptor InfoFrame)
                 */
                infopacket->hb0 = DC_HDMI_INFOFRAME_TYPE_SPD;

                /* HB1  = Version = 0x03 */
                infopacket->hb1 = version;

                /* HB2  = [Bits 7:5 = 0] [Bits 4:0 = Length] */
                *payload_size = 0x10;
                infopacket->hb2 = *payload_size - 1; //-1 for checksum

        } else if (dc_is_dp_signal(signal)) {

                /* HEADER */

                /* HB0  = Secondary-data Packet ID = 0 - Only non-zero
                 *        when used to associate audio related info packets
                 */
                infopacket->hb0 = 0x00;

                /* HB1  = Packet Type = 0x83 (Source Product
                 *        Descriptor InfoFrame)
                 */
                infopacket->hb1 = DC_HDMI_INFOFRAME_TYPE_SPD;

                /* HB2  = [Bits 7:0 = Least significant eight bits -
                 *        For INFOFRAME, the value must be 1Bh]
                 */
                infopacket->hb2 = 0x1B;

                /* HB3  = [Bits 7:2 = INFOFRAME SDP Version Number = 0x2]
                 *        [Bits 1:0 = Most significant two bits = 0x00]
                 */

                infopacket->hb3 = (version & 0x3F) << 2;

                *payload_size = 0x1B;
        }
}

static void build_vrr_infopacket_checksum(unsigned int *payload_size,
                struct dc_info_packet *infopacket)
{
        /* Calculate checksum */
        unsigned int idx = 0;
        unsigned char checksum = 0;

        checksum += infopacket->hb0;
        checksum += infopacket->hb1;
        checksum += infopacket->hb2;
        checksum += infopacket->hb3;

        for (idx = 1; idx <= *payload_size; idx++)
                checksum += infopacket->sb[idx];

        /* PB0 = Checksum (one byte complement) */
        infopacket->sb[0] = (unsigned char)(0x100 - checksum);

        infopacket->valid = true;
}

static void build_vrr_infopacket_v1(enum signal_type signal,
                const struct mod_vrr_params *vrr,
                struct dc_info_packet *infopacket)
{
        /* SPD info packet for FreeSync */
        unsigned int payload_size = 0;

        build_vrr_infopacket_header_v1(signal, infopacket, &payload_size);
        build_vrr_infopacket_data_v1(vrr, infopacket);
        build_vrr_infopacket_checksum(&payload_size, infopacket);

        infopacket->valid = true;
}

static void build_vrr_infopacket_v2(enum signal_type signal,
                const struct mod_vrr_params *vrr,
                enum color_transfer_func app_tf,
                struct dc_info_packet *infopacket)
{
        unsigned int payload_size = 0;

        build_vrr_infopacket_header_v2(signal, infopacket, &payload_size);
        build_vrr_infopacket_data_v1(vrr, infopacket);

        build_vrr_infopacket_fs2_data(app_tf, infopacket);

        build_vrr_infopacket_checksum(&payload_size, infopacket);

        infopacket->valid = true;
}
#ifndef TRIM_FSFT
static void build_vrr_infopacket_fast_transport_data(
        bool ftActive,
        unsigned int ftOutputRate,
        struct dc_info_packet *infopacket)
{
        /* PB9 : bit7 - fast transport Active*/
        unsigned char activeBit = (ftActive) ? 1 << 7 : 0;

        infopacket->sb[1] &= ~activeBit;  //clear bit
        infopacket->sb[1] |=  activeBit;  //set bit

        /* PB13 : Target Output Pixel Rate [kHz] - bits 7:0  */
        infopacket->sb[13] = ftOutputRate & 0xFF;

        /* PB14 : Target Output Pixel Rate [kHz] - bits 15:8  */
        infopacket->sb[14] = (ftOutputRate >> 8) & 0xFF;

        /* PB15 : Target Output Pixel Rate [kHz] - bits 23:16  */
        infopacket->sb[15] = (ftOutputRate >> 16) & 0xFF;

}
#endif

static void build_vrr_infopacket_v3(enum signal_type signal,
                const struct mod_vrr_params *vrr,
#ifndef TRIM_FSFT
                bool ftActive, unsigned int ftOutputRate,
#endif
                enum color_transfer_func app_tf,
                struct dc_info_packet *infopacket)
{
        unsigned int payload_size = 0;

        build_vrr_infopacket_header_v3(signal, infopacket, &payload_size);
        build_vrr_infopacket_data_v3(vrr, infopacket);

        build_vrr_infopacket_fs2_data(app_tf, infopacket);

#ifndef TRIM_FSFT
        build_vrr_infopacket_fast_transport_data(
                        ftActive,
                        ftOutputRate,
                        infopacket);
#endif

        build_vrr_infopacket_checksum(&payload_size, infopacket);

        infopacket->valid = true;
}

void mod_freesync_build_vrr_infopacket(struct mod_freesync *mod_freesync,
                const struct dc_stream_state *stream,
                const struct mod_vrr_params *vrr,
                enum vrr_packet_type packet_type,
                enum color_transfer_func app_tf,
                struct dc_info_packet *infopacket)
{
        /* SPD info packet for FreeSync
         * VTEM info packet for HdmiVRR
         * Check if Freesync is supported. Return if false. If true,
         * set the corresponding bit in the info packet
         */
        if (!vrr->send_info_frame)
                return;

        switch (packet_type) {
        case PACKET_TYPE_FS_V3:
#ifndef TRIM_FSFT
                // always populate with pixel rate.
                build_vrr_infopacket_v3(
                                stream->signal, vrr,
                                stream->timing.flags.FAST_TRANSPORT,
                                (stream->timing.flags.FAST_TRANSPORT) ?
                                                stream->timing.fast_transport_output_rate_100hz :
                                                stream->timing.pix_clk_100hz,
                                app_tf, infopacket);
#else
                build_vrr_infopacket_v3(stream->signal, vrr, app_tf, infopacket);
#endif
                break;
        case PACKET_TYPE_FS_V2:
                build_vrr_infopacket_v2(stream->signal, vrr, app_tf, infopacket);
                break;
        case PACKET_TYPE_VRR:
        case PACKET_TYPE_FS_V1:
        default:
                build_vrr_infopacket_v1(stream->signal, vrr, infopacket);
        }
}

void mod_freesync_build_vrr_params(struct mod_freesync *mod_freesync,
                const struct dc_stream_state *stream,
                struct mod_freesync_config *in_config,
                struct mod_vrr_params *in_out_vrr)
{
        struct core_freesync *core_freesync = NULL;
        unsigned long long nominal_field_rate_in_uhz = 0;
        unsigned long long rounded_nominal_in_uhz = 0;
        unsigned int refresh_range = 0;
        unsigned long long min_refresh_in_uhz = 0;
        unsigned long long max_refresh_in_uhz = 0;

        if (mod_freesync == NULL)
                return;

        core_freesync = MOD_FREESYNC_TO_CORE(mod_freesync);

        /* Calculate nominal field rate for stream */
        nominal_field_rate_in_uhz =
                        mod_freesync_calc_nominal_field_rate(stream);

        min_refresh_in_uhz = in_config->min_refresh_in_uhz;
        max_refresh_in_uhz = in_config->max_refresh_in_uhz;

        /* Full range may be larger than current video timing, so cap at nominal */
        if (max_refresh_in_uhz > nominal_field_rate_in_uhz)
                max_refresh_in_uhz = nominal_field_rate_in_uhz;

        /* Full range may be larger than current video timing, so cap at nominal */
        if (min_refresh_in_uhz > max_refresh_in_uhz)
                min_refresh_in_uhz = max_refresh_in_uhz;

        /* If a monitor reports exactly max refresh of 2x of min, enforce it on nominal */
        rounded_nominal_in_uhz =
                        div_u64(nominal_field_rate_in_uhz + 50000, 100000) * 100000;
        if (in_config->max_refresh_in_uhz == (2 * in_config->min_refresh_in_uhz) &&
                in_config->max_refresh_in_uhz == rounded_nominal_in_uhz)
                min_refresh_in_uhz = div_u64(nominal_field_rate_in_uhz, 2);

        if (!vrr_settings_require_update(core_freesync,
                        in_config, (unsigned int)min_refresh_in_uhz, (unsigned int)max_refresh_in_uhz,
                        in_out_vrr))
                return;

        in_out_vrr->state = in_config->state;
        in_out_vrr->send_info_frame = in_config->vsif_supported;

        if (in_config->state == VRR_STATE_UNSUPPORTED) {
                in_out_vrr->state = VRR_STATE_UNSUPPORTED;
                in_out_vrr->supported = false;
                in_out_vrr->adjust.v_total_min = stream->timing.v_total;
                in_out_vrr->adjust.v_total_max = stream->timing.v_total;

                return;

        } else {
                in_out_vrr->min_refresh_in_uhz = (unsigned int)min_refresh_in_uhz;
                in_out_vrr->max_duration_in_us =
                                calc_duration_in_us_from_refresh_in_uhz(
                                                (unsigned int)min_refresh_in_uhz);

                in_out_vrr->max_refresh_in_uhz = (unsigned int)max_refresh_in_uhz;
                in_out_vrr->min_duration_in_us =
                                calc_duration_in_us_from_refresh_in_uhz(
                                                (unsigned int)max_refresh_in_uhz);

                if (in_config->state == VRR_STATE_ACTIVE_FIXED)
                        in_out_vrr->fixed_refresh_in_uhz = in_config->fixed_refresh_in_uhz;
                else
                        in_out_vrr->fixed_refresh_in_uhz = 0;

                refresh_range = div_u64(in_out_vrr->max_refresh_in_uhz + 500000, 1000000) -
+                               div_u64(in_out_vrr->min_refresh_in_uhz + 500000, 1000000);

                in_out_vrr->supported = true;
        }

        in_out_vrr->fixed.ramping_active = in_config->ramping;

        in_out_vrr->btr.btr_enabled = in_config->btr;

        if (in_out_vrr->max_refresh_in_uhz < (2 * in_out_vrr->min_refresh_in_uhz))
                in_out_vrr->btr.btr_enabled = false;
        else {
                in_out_vrr->btr.margin_in_us = in_out_vrr->max_duration_in_us -
                                2 * in_out_vrr->min_duration_in_us;
                if (in_out_vrr->btr.margin_in_us > BTR_MAX_MARGIN)
                        in_out_vrr->btr.margin_in_us = BTR_MAX_MARGIN;
        }

        in_out_vrr->btr.btr_active = false;
        in_out_vrr->btr.inserted_duration_in_us = 0;
        in_out_vrr->btr.frames_to_insert = 0;
        in_out_vrr->btr.frame_counter = 0;
        in_out_vrr->fixed.fixed_active = false;
        in_out_vrr->fixed.target_refresh_in_uhz = 0;

        in_out_vrr->btr.mid_point_in_us =
                                (in_out_vrr->min_duration_in_us +
                                 in_out_vrr->max_duration_in_us) / 2;

        if (in_out_vrr->state == VRR_STATE_UNSUPPORTED) {
                in_out_vrr->adjust.v_total_min = stream->timing.v_total;
                in_out_vrr->adjust.v_total_max = stream->timing.v_total;
        } else if (in_out_vrr->state == VRR_STATE_DISABLED) {
                in_out_vrr->adjust.v_total_min = stream->timing.v_total;
                in_out_vrr->adjust.v_total_max = stream->timing.v_total;
        } else if (in_out_vrr->state == VRR_STATE_INACTIVE) {
                in_out_vrr->adjust.v_total_min = stream->timing.v_total;
                in_out_vrr->adjust.v_total_max = stream->timing.v_total;
        } else if (in_out_vrr->state == VRR_STATE_ACTIVE_VARIABLE &&
                        refresh_range >= MIN_REFRESH_RANGE) {

                in_out_vrr->adjust.v_total_min =
                        calc_v_total_from_refresh(stream,
                                in_out_vrr->max_refresh_in_uhz);
                in_out_vrr->adjust.v_total_max =
                        calc_v_total_from_refresh(stream,
                                in_out_vrr->min_refresh_in_uhz);
        } else if (in_out_vrr->state == VRR_STATE_ACTIVE_FIXED) {
                in_out_vrr->fixed.target_refresh_in_uhz =
                                in_out_vrr->fixed_refresh_in_uhz;
                if (in_out_vrr->fixed.ramping_active &&
                                in_out_vrr->fixed.fixed_active) {
                        /* Do not update vtotals if ramping is already active
                         * in order to continue ramp from current refresh.
                         */
                        in_out_vrr->fixed.fixed_active = true;
                } else {
                        in_out_vrr->fixed.fixed_active = true;
                        in_out_vrr->adjust.v_total_min =
                                calc_v_total_from_refresh(stream,
                                        in_out_vrr->fixed.target_refresh_in_uhz);
                        in_out_vrr->adjust.v_total_max =
                                in_out_vrr->adjust.v_total_min;
                }
        } else {
                in_out_vrr->state = VRR_STATE_INACTIVE;
                in_out_vrr->adjust.v_total_min = stream->timing.v_total;
                in_out_vrr->adjust.v_total_max = stream->timing.v_total;
        }
}

void mod_freesync_handle_preflip(struct mod_freesync *mod_freesync,
                const struct dc_plane_state *plane,
                const struct dc_stream_state *stream,
                unsigned int curr_time_stamp_in_us,
                struct mod_vrr_params *in_out_vrr)
{
        struct core_freesync *core_freesync = NULL;
        unsigned int last_render_time_in_us = 0;
        unsigned int average_render_time_in_us = 0;

        if (mod_freesync == NULL)
                return;

        core_freesync = MOD_FREESYNC_TO_CORE(mod_freesync);

        if (in_out_vrr->supported &&
                        in_out_vrr->state == VRR_STATE_ACTIVE_VARIABLE) {
                unsigned int i = 0;
                unsigned int oldest_index = plane->time.index + 1;

                if (oldest_index >= DC_PLANE_UPDATE_TIMES_MAX)
                        oldest_index = 0;

                last_render_time_in_us = curr_time_stamp_in_us -
                                plane->time.prev_update_time_in_us;

                /* Sum off all entries except oldest one */
                for (i = 0; i < DC_PLANE_UPDATE_TIMES_MAX; i++) {
                        average_render_time_in_us +=
                                        plane->time.time_elapsed_in_us[i];
                }
                average_render_time_in_us -=
                                plane->time.time_elapsed_in_us[oldest_index];

                /* Add render time for current flip */
                average_render_time_in_us += last_render_time_in_us;
                average_render_time_in_us /= DC_PLANE_UPDATE_TIMES_MAX;

                if (in_out_vrr->btr.btr_enabled) {
                        apply_below_the_range(core_freesync,
                                        stream,
                                        last_render_time_in_us,
                                        in_out_vrr);
                } else {
                        apply_fixed_refresh(core_freesync,
                                stream,
                                last_render_time_in_us,
                                in_out_vrr);
                }

        }
}

void mod_freesync_handle_v_update(struct mod_freesync *mod_freesync,
                const struct dc_stream_state *stream,
                struct mod_vrr_params *in_out_vrr)
{
        struct core_freesync *core_freesync = NULL;

        if ((mod_freesync == NULL) || (stream == NULL) || (in_out_vrr == NULL))
                return;

        core_freesync = MOD_FREESYNC_TO_CORE(mod_freesync);

        if (in_out_vrr->supported == false)
                return;

        /* Below the Range Logic */

        /* Only execute if in fullscreen mode */
        if (in_out_vrr->state == VRR_STATE_ACTIVE_VARIABLE &&
                                        in_out_vrr->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 (in_out_vrr->btr.frames_to_insert ==
                                in_out_vrr->btr.frame_counter) {
                        in_out_vrr->adjust.v_total_min =
                                calc_v_total_from_duration(stream,
                                in_out_vrr,
                                in_out_vrr->btr.inserted_duration_in_us);
                        in_out_vrr->adjust.v_total_max =
                                in_out_vrr->adjust.v_total_min;
                }

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

                /* Restore FreeSync */
                if (in_out_vrr->btr.frame_counter == 0) {
                        in_out_vrr->adjust.v_total_min =
                                calc_v_total_from_refresh(stream,
                                in_out_vrr->max_refresh_in_uhz);
                        in_out_vrr->adjust.v_total_max =
                                calc_v_total_from_refresh(stream,
                                in_out_vrr->min_refresh_in_uhz);
                }
        }

        /* If in fullscreen freesync mode or in video, do not program
         * static screen ramp values
         */
        if (in_out_vrr->state == VRR_STATE_ACTIVE_VARIABLE)
                in_out_vrr->fixed.ramping_active = false;

        /* Gradual Static Screen Ramping Logic
         * Execute if ramp is active and user enabled freesync static screen
         */
        if (in_out_vrr->state == VRR_STATE_ACTIVE_FIXED &&
                                in_out_vrr->fixed.ramping_active) {
                update_v_total_for_static_ramp(
                                core_freesync, stream, in_out_vrr);
        }
}

void mod_freesync_get_settings(struct mod_freesync *mod_freesync,
                const struct mod_vrr_params *vrr,
                unsigned int *v_total_min, unsigned int *v_total_max,
                unsigned int *event_triggers,
                unsigned int *window_min, unsigned int *window_max,
                unsigned int *lfc_mid_point_in_us,
                unsigned int *inserted_frames,
                unsigned int *inserted_duration_in_us)
{
        if (mod_freesync == NULL)
                return;

        if (vrr->supported) {
                *v_total_min = vrr->adjust.v_total_min;
                *v_total_max = vrr->adjust.v_total_max;
                *event_triggers = 0;
                *lfc_mid_point_in_us = vrr->btr.mid_point_in_us;
                *inserted_frames = vrr->btr.frames_to_insert;
                *inserted_duration_in_us = vrr->btr.inserted_duration_in_us;
        }
}

unsigned long long mod_freesync_calc_nominal_field_rate(
                        const struct dc_stream_state *stream)
{
        unsigned long long nominal_field_rate_in_uhz = 0;
        unsigned int total = stream->timing.h_total * stream->timing.v_total;

        /* Calculate nominal field rate for stream, rounded up to nearest integer */
        nominal_field_rate_in_uhz = stream->timing.pix_clk_100hz;
        nominal_field_rate_in_uhz *= 100000000ULL;

        nominal_field_rate_in_uhz =     div_u64(nominal_field_rate_in_uhz, total);

        return nominal_field_rate_in_uhz;
}

bool mod_freesync_is_valid_range(uint32_t min_refresh_cap_in_uhz,
                uint32_t max_refresh_cap_in_uhz,
                uint32_t nominal_field_rate_in_uhz) 
{

        /* Typically nominal refresh calculated can have some fractional part.
         * Allow for some rounding error of actual video timing by taking floor
         * of caps and request. Round the nominal refresh rate.
         *
         * Dividing will convert everything to units in Hz although input
         * variable name is in uHz!
         *
         * Also note, this takes care of rounding error on the nominal refresh
         * so by rounding error we only expect it to be off by a small amount,
         * such as < 0.1 Hz. i.e. 143.9xxx or 144.1xxx.
         *
         * Example 1. Caps    Min = 40 Hz, Max = 144 Hz
         *            Request Min = 40 Hz, Max = 144 Hz
         *                    Nominal = 143.5x Hz rounded to 144 Hz
         *            This function should allow this as valid request
         *
         * Example 2. Caps    Min = 40 Hz, Max = 144 Hz
         *            Request Min = 40 Hz, Max = 144 Hz
         *                    Nominal = 144.4x Hz rounded to 144 Hz
         *            This function should allow this as valid request
         *
         * Example 3. Caps    Min = 40 Hz, Max = 144 Hz
         *            Request Min = 40 Hz, Max = 144 Hz
         *                    Nominal = 120.xx Hz rounded to 120 Hz
         *            This function should return NOT valid since the requested
         *            max is greater than current timing's nominal
         *
         * Example 4. Caps    Min = 40 Hz, Max = 120 Hz
         *            Request Min = 40 Hz, Max = 120 Hz
         *                    Nominal = 144.xx Hz rounded to 144 Hz
         *            This function should return NOT valid since the nominal
         *            is greater than the capability's max refresh
         */
        nominal_field_rate_in_uhz =
                        div_u64(nominal_field_rate_in_uhz + 500000, 1000000);
        min_refresh_cap_in_uhz /= 1000000;
        max_refresh_cap_in_uhz /= 1000000;

        /* Check nominal is within range */
        if (nominal_field_rate_in_uhz > max_refresh_cap_in_uhz ||
                nominal_field_rate_in_uhz < min_refresh_cap_in_uhz)
                return false;

        /* If nominal is less than max, limit the max allowed refresh rate */
        if (nominal_field_rate_in_uhz < max_refresh_cap_in_uhz)
                max_refresh_cap_in_uhz = nominal_field_rate_in_uhz;

        /* Check min is within range */
        if (min_refresh_cap_in_uhz > max_refresh_cap_in_uhz)
                return false;

        /* For variable range, check for at least 10 Hz range */
        if (nominal_field_rate_in_uhz - min_refresh_cap_in_uhz < 10)
                return false;

        return true;
}