/*
 * Copyright 2012-15 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 "atomfirmware.h"
#include "dm_helpers.h"
#include "dc.h"
#include "grph_object_id.h"
#include "gpio_service_interface.h"
#include "core_status.h"
#include "dc_link_dp.h"
#include "dc_link_ddc.h"
#include "link_hwss.h"
#include "opp.h"

#include "link_encoder.h"
#include "hw_sequencer.h"
#include "resource.h"
#include "abm.h"
#include "fixed31_32.h"
#include "dpcd_defs.h"
#include "dmcu.h"
#include "hw/clk_mgr.h"
#include "dce/dmub_psr.h"
#include "dmub/dmub_srv.h"
#include "inc/hw/panel_cntl.h"
#include "inc/link_enc_cfg.h"
#include "inc/link_dpcd.h"

#define DC_LOGGER_INIT(logger)

#define LINK_INFO(...) \
        DC_LOG_HW_HOTPLUG(  \
                __VA_ARGS__)

#define RETIMER_REDRIVER_INFO(...) \
        DC_LOG_RETIMER_REDRIVER(  \
                __VA_ARGS__)

/*******************************************************************************
 * Private functions
 ******************************************************************************/
static void dc_link_destruct(struct dc_link *link)
{
        int i;

        if (link->hpd_gpio) {
                dal_gpio_destroy_irq(&link->hpd_gpio);
                link->hpd_gpio = NULL;
        }

        if (link->ddc)
                dal_ddc_service_destroy(&link->ddc);

        if (link->panel_cntl)
                link->panel_cntl->funcs->destroy(&link->panel_cntl);

        if (link->link_enc) {
                /* Update link encoder resource tracking variables. These are used for
                 * the dynamic assignment of link encoders to streams. Virtual links
                 * are not assigned encoder resources on creation.
                 */
                if (link->link_id.id != CONNECTOR_ID_VIRTUAL) {
                        link->dc->res_pool->link_encoders[link->eng_id - ENGINE_ID_DIGA] = NULL;
                        link->dc->res_pool->dig_link_enc_count--;
                }
                link->link_enc->funcs->destroy(&link->link_enc);
        }

        if (link->local_sink)
                dc_sink_release(link->local_sink);

        for (i = 0; i < link->sink_count; ++i)
                dc_sink_release(link->remote_sinks[i]);
}

struct gpio *get_hpd_gpio(struct dc_bios *dcb,
                          struct graphics_object_id link_id,
                          struct gpio_service *gpio_service)
{
        enum bp_result bp_result;
        struct graphics_object_hpd_info hpd_info;
        struct gpio_pin_info pin_info;

        if (dcb->funcs->get_hpd_info(dcb, link_id, &hpd_info) != BP_RESULT_OK)
                return NULL;

        bp_result = dcb->funcs->get_gpio_pin_info(dcb,
                hpd_info.hpd_int_gpio_uid, &pin_info);

        if (bp_result != BP_RESULT_OK) {
                ASSERT(bp_result == BP_RESULT_NORECORD);
                return NULL;
        }

        return dal_gpio_service_create_irq(gpio_service,
                                           pin_info.offset,
                                           pin_info.mask);
}

/*
 *  Function: program_hpd_filter
 *
 *  @brief
 *     Programs HPD filter on associated HPD line
 *
 *  @param [in] delay_on_connect_in_ms: Connect filter timeout
 *  @param [in] delay_on_disconnect_in_ms: Disconnect filter timeout
 *
 *  @return
 *     true on success, false otherwise
 */
static bool program_hpd_filter(const struct dc_link *link)
{
        bool result = false;
        struct gpio *hpd;
        int delay_on_connect_in_ms = 0;
        int delay_on_disconnect_in_ms = 0;

        if (link->is_hpd_filter_disabled)
                return false;
        /* Verify feature is supported */
        switch (link->connector_signal) {
        case SIGNAL_TYPE_DVI_SINGLE_LINK:
        case SIGNAL_TYPE_DVI_DUAL_LINK:
        case SIGNAL_TYPE_HDMI_TYPE_A:
                /* Program hpd filter */
                delay_on_connect_in_ms = 500;
                delay_on_disconnect_in_ms = 100;
                break;
        case SIGNAL_TYPE_DISPLAY_PORT:
        case SIGNAL_TYPE_DISPLAY_PORT_MST:
                /* Program hpd filter to allow DP signal to settle */
                /* 500: not able to detect MST <-> SST switch as HPD is low for
                 * only 100ms on DELL U2413
                 * 0: some passive dongle still show aux mode instead of i2c
                 * 20-50: not enough to hide bouncing HPD with passive dongle.
                 * also see intermittent i2c read issues.
                 */
                delay_on_connect_in_ms = 80;
                delay_on_disconnect_in_ms = 0;
                break;
        case SIGNAL_TYPE_LVDS:
        case SIGNAL_TYPE_EDP:
        default:
                /* Don't program hpd filter */
                return false;
        }

        /* Obtain HPD handle */
        hpd = get_hpd_gpio(link->ctx->dc_bios, link->link_id,
                           link->ctx->gpio_service);

        if (!hpd)
                return result;

        /* Setup HPD filtering */
        if (dal_gpio_open(hpd, GPIO_MODE_INTERRUPT) == GPIO_RESULT_OK) {
                struct gpio_hpd_config config;

                config.delay_on_connect = delay_on_connect_in_ms;
                config.delay_on_disconnect = delay_on_disconnect_in_ms;

                dal_irq_setup_hpd_filter(hpd, &config);

                dal_gpio_close(hpd);

                result = true;
        } else {
                ASSERT_CRITICAL(false);
        }

        /* Release HPD handle */
        dal_gpio_destroy_irq(&hpd);

        return result;
}

bool dc_link_wait_for_t12(struct dc_link *link)
{
        if (link->connector_signal == SIGNAL_TYPE_EDP && link->dc->hwss.edp_wait_for_T12) {
                link->dc->hwss.edp_wait_for_T12(link);

                return true;
        }

        return false;
}

/**
 * dc_link_detect_sink() - Determine if there is a sink connected
 *
 * @link: pointer to the dc link
 * @type: Returned connection type
 * Does not detect downstream devices, such as MST sinks
 * or display connected through active dongles
 */
bool dc_link_detect_sink(struct dc_link *link, enum dc_connection_type *type)
{
        uint32_t is_hpd_high = 0;
        struct gpio *hpd_pin;

        if (link->connector_signal == SIGNAL_TYPE_LVDS) {
                *type = dc_connection_single;
                return true;
        }

        if (link->connector_signal == SIGNAL_TYPE_EDP) {
                /*in case it is not on*/
                link->dc->hwss.edp_power_control(link, true);
                link->dc->hwss.edp_wait_for_hpd_ready(link, true);
        }

        /* Link may not have physical HPD pin. */
        if (link->ep_type != DISPLAY_ENDPOINT_PHY) {
                if (link->hpd_status)
                        *type = dc_connection_single;
                else
                        *type = dc_connection_none;

                return true;
        }

        /* todo: may need to lock gpio access */
        hpd_pin = get_hpd_gpio(link->ctx->dc_bios, link->link_id,
                               link->ctx->gpio_service);
        if (!hpd_pin)
                goto hpd_gpio_failure;

        dal_gpio_open(hpd_pin, GPIO_MODE_INTERRUPT);
        dal_gpio_get_value(hpd_pin, &is_hpd_high);
        dal_gpio_close(hpd_pin);
        dal_gpio_destroy_irq(&hpd_pin);

        if (is_hpd_high) {
                *type = dc_connection_single;
                /* TODO: need to do the actual detection */
        } else {
                *type = dc_connection_none;
        }

        return true;

hpd_gpio_failure:
        return false;
}

static enum ddc_transaction_type get_ddc_transaction_type(enum signal_type sink_signal)
{
        enum ddc_transaction_type transaction_type = DDC_TRANSACTION_TYPE_NONE;

        switch (sink_signal) {
        case SIGNAL_TYPE_DVI_SINGLE_LINK:
        case SIGNAL_TYPE_DVI_DUAL_LINK:
        case SIGNAL_TYPE_HDMI_TYPE_A:
        case SIGNAL_TYPE_LVDS:
        case SIGNAL_TYPE_RGB:
                transaction_type = DDC_TRANSACTION_TYPE_I2C;
                break;

        case SIGNAL_TYPE_DISPLAY_PORT:
        case SIGNAL_TYPE_EDP:
                transaction_type = DDC_TRANSACTION_TYPE_I2C_OVER_AUX;
                break;

        case SIGNAL_TYPE_DISPLAY_PORT_MST:
                /* MST does not use I2COverAux, but there is the
                 * SPECIAL use case for "immediate dwnstrm device
                 * access" (EPR#370830).
                 */
                transaction_type = DDC_TRANSACTION_TYPE_I2C_OVER_AUX;
                break;

        default:
                break;
        }

        return transaction_type;
}

static enum signal_type get_basic_signal_type(struct graphics_object_id encoder,
                                              struct graphics_object_id downstream)
{
        if (downstream.type == OBJECT_TYPE_CONNECTOR) {
                switch (downstream.id) {
                case CONNECTOR_ID_SINGLE_LINK_DVII:
                        switch (encoder.id) {
                        case ENCODER_ID_INTERNAL_DAC1:
                        case ENCODER_ID_INTERNAL_KLDSCP_DAC1:
                        case ENCODER_ID_INTERNAL_DAC2:
                        case ENCODER_ID_INTERNAL_KLDSCP_DAC2:
                                return SIGNAL_TYPE_RGB;
                        default:
                                return SIGNAL_TYPE_DVI_SINGLE_LINK;
                        }
                break;
                case CONNECTOR_ID_DUAL_LINK_DVII:
                {
                        switch (encoder.id) {
                        case ENCODER_ID_INTERNAL_DAC1:
                        case ENCODER_ID_INTERNAL_KLDSCP_DAC1:
                        case ENCODER_ID_INTERNAL_DAC2:
                        case ENCODER_ID_INTERNAL_KLDSCP_DAC2:
                                return SIGNAL_TYPE_RGB;
                        default:
                                return SIGNAL_TYPE_DVI_DUAL_LINK;
                        }
                }
                break;
                case CONNECTOR_ID_SINGLE_LINK_DVID:
                        return SIGNAL_TYPE_DVI_SINGLE_LINK;
                case CONNECTOR_ID_DUAL_LINK_DVID:
                        return SIGNAL_TYPE_DVI_DUAL_LINK;
                case CONNECTOR_ID_VGA:
                        return SIGNAL_TYPE_RGB;
                case CONNECTOR_ID_HDMI_TYPE_A:
                        return SIGNAL_TYPE_HDMI_TYPE_A;
                case CONNECTOR_ID_LVDS:
                        return SIGNAL_TYPE_LVDS;
                case CONNECTOR_ID_DISPLAY_PORT:
                        return SIGNAL_TYPE_DISPLAY_PORT;
                case CONNECTOR_ID_EDP:
                        return SIGNAL_TYPE_EDP;
                default:
                        return SIGNAL_TYPE_NONE;
                }
        } else if (downstream.type == OBJECT_TYPE_ENCODER) {
                switch (downstream.id) {
                case ENCODER_ID_EXTERNAL_NUTMEG:
                case ENCODER_ID_EXTERNAL_TRAVIS:
                        return SIGNAL_TYPE_DISPLAY_PORT;
                default:
                        return SIGNAL_TYPE_NONE;
                }
        }

        return SIGNAL_TYPE_NONE;
}

/*
 * dc_link_is_dp_sink_present() - Check if there is a native DP
 * or passive DP-HDMI dongle connected
 */
bool dc_link_is_dp_sink_present(struct dc_link *link)
{
        enum gpio_result gpio_result;
        uint32_t clock_pin = 0;
        uint8_t retry = 0;
        struct ddc *ddc;

        enum connector_id connector_id =
                dal_graphics_object_id_get_connector_id(link->link_id);

        bool present =
                ((connector_id == CONNECTOR_ID_DISPLAY_PORT) ||
                (connector_id == CONNECTOR_ID_EDP));

        ddc = dal_ddc_service_get_ddc_pin(link->ddc);

        if (!ddc) {
                BREAK_TO_DEBUGGER();
                return present;
        }

        /* Open GPIO and set it to I2C mode */
        /* Note: this GpioMode_Input will be converted
         * to GpioConfigType_I2cAuxDualMode in GPIO component,
         * which indicates we need additional delay
         */

        if (dal_ddc_open(ddc, GPIO_MODE_INPUT,
                         GPIO_DDC_CONFIG_TYPE_MODE_I2C) != GPIO_RESULT_OK) {
                dal_ddc_close(ddc);

                return present;
        }

        /*
         * Read GPIO: DP sink is present if both clock and data pins are zero
         *
         * [W/A] plug-unplug DP cable, sometimes customer board has
         * one short pulse on clk_pin(1V, < 1ms). DP will be config to HDMI/DVI
         * then monitor can't br light up. Add retry 3 times
         * But in real passive dongle, it need additional 3ms to detect
         */
        do {
                gpio_result = dal_gpio_get_value(ddc->pin_clock, &clock_pin);
                ASSERT(gpio_result == GPIO_RESULT_OK);
                if (clock_pin)
                        udelay(1000);
                else
                        break;
        } while (retry++ < 3);

        present = (gpio_result == GPIO_RESULT_OK) && !clock_pin;

        dal_ddc_close(ddc);

        return present;
}

/*
 * @brief
 * Detect output sink type
 */
static enum signal_type link_detect_sink(struct dc_link *link,
                                         enum dc_detect_reason reason)
{
        enum signal_type result;
        struct graphics_object_id enc_id;

        if (link->is_dig_mapping_flexible)
                enc_id = (struct graphics_object_id){.id = ENCODER_ID_UNKNOWN};
        else
                enc_id = link->link_enc->id;
        result = get_basic_signal_type(enc_id, link->link_id);

        /* Use basic signal type for link without physical connector. */
        if (link->ep_type != DISPLAY_ENDPOINT_PHY)
                return result;

        /* Internal digital encoder will detect only dongles
         * that require digital signal
         */

        /* Detection mechanism is different
         * for different native connectors.
         * LVDS connector supports only LVDS signal;
         * PCIE is a bus slot, the actual connector needs to be detected first;
         * eDP connector supports only eDP signal;
         * HDMI should check straps for audio
         */

        /* PCIE detects the actual connector on add-on board */
        if (link->link_id.id == CONNECTOR_ID_PCIE) {
                /* ZAZTODO implement PCIE add-on card detection */
        }

        switch (link->link_id.id) {
        case CONNECTOR_ID_HDMI_TYPE_A: {
                /* check audio support:
                 * if native HDMI is not supported, switch to DVI
                 */
                struct audio_support *aud_support =
                                        &link->dc->res_pool->audio_support;

                if (!aud_support->hdmi_audio_native)
                        if (link->link_id.id == CONNECTOR_ID_HDMI_TYPE_A)
                                result = SIGNAL_TYPE_DVI_SINGLE_LINK;
        }
        break;
        case CONNECTOR_ID_DISPLAY_PORT: {
                /* DP HPD short pulse. Passive DP dongle will not
                 * have short pulse
                 */
                if (reason != DETECT_REASON_HPDRX) {
                        /* Check whether DP signal detected: if not -
                         * we assume signal is DVI; it could be corrected
                         * to HDMI after dongle detection
                         */
                        if (!dm_helpers_is_dp_sink_present(link))
                                result = SIGNAL_TYPE_DVI_SINGLE_LINK;
                }
        }
        break;
        default:
        break;
        }

        return result;
}

static enum signal_type decide_signal_from_strap_and_dongle_type(enum display_dongle_type dongle_type,
                                                                 struct audio_support *audio_support)
{
        enum signal_type signal = SIGNAL_TYPE_NONE;

        switch (dongle_type) {
        case DISPLAY_DONGLE_DP_HDMI_DONGLE:
                if (audio_support->hdmi_audio_on_dongle)
                        signal = SIGNAL_TYPE_HDMI_TYPE_A;
                else
                        signal = SIGNAL_TYPE_DVI_SINGLE_LINK;
                break;
        case DISPLAY_DONGLE_DP_DVI_DONGLE:
                signal = SIGNAL_TYPE_DVI_SINGLE_LINK;
                break;
        case DISPLAY_DONGLE_DP_HDMI_MISMATCHED_DONGLE:
                if (audio_support->hdmi_audio_native)
                        signal =  SIGNAL_TYPE_HDMI_TYPE_A;
                else
                        signal = SIGNAL_TYPE_DVI_SINGLE_LINK;
                break;
        default:
                signal = SIGNAL_TYPE_NONE;
                break;
        }

        return signal;
}

static enum signal_type dp_passive_dongle_detection(struct ddc_service *ddc,
                                                    struct display_sink_capability *sink_cap,
                                                    struct audio_support *audio_support)
{
        dal_ddc_service_i2c_query_dp_dual_mode_adaptor(ddc, sink_cap);

        return decide_signal_from_strap_and_dongle_type(sink_cap->dongle_type,
                                                        audio_support);
}

static void link_disconnect_sink(struct dc_link *link)
{
        if (link->local_sink) {
                dc_sink_release(link->local_sink);
                link->local_sink = NULL;
        }

        link->dpcd_sink_count = 0;
}

static void link_disconnect_remap(struct dc_sink *prev_sink, struct dc_link *link)
{
        dc_sink_release(link->local_sink);
        link->local_sink = prev_sink;
}

#if defined(CONFIG_DRM_AMD_DC_HDCP)
bool dc_link_is_hdcp14(struct dc_link *link, enum signal_type signal)
{
        bool ret = false;

        switch (signal) {
        case SIGNAL_TYPE_DISPLAY_PORT:
        case SIGNAL_TYPE_DISPLAY_PORT_MST:
                ret = link->hdcp_caps.bcaps.bits.HDCP_CAPABLE;
                break;
        case SIGNAL_TYPE_DVI_SINGLE_LINK:
        case SIGNAL_TYPE_DVI_DUAL_LINK:
        case SIGNAL_TYPE_HDMI_TYPE_A:
        /* HDMI doesn't tell us its HDCP(1.4) capability, so assume to always be capable,
         * we can poll for bksv but some displays have an issue with this. Since its so rare
         * for a display to not be 1.4 capable, this assumtion is ok
         */
                ret = true;
                break;
        default:
                break;
        }
        return ret;
}

bool dc_link_is_hdcp22(struct dc_link *link, enum signal_type signal)
{
        bool ret = false;

        switch (signal) {
        case SIGNAL_TYPE_DISPLAY_PORT:
        case SIGNAL_TYPE_DISPLAY_PORT_MST:
                ret = (link->hdcp_caps.bcaps.bits.HDCP_CAPABLE &&
                                link->hdcp_caps.rx_caps.fields.byte0.hdcp_capable &&
                                (link->hdcp_caps.rx_caps.fields.version == 0x2)) ? 1 : 0;
                break;
        case SIGNAL_TYPE_DVI_SINGLE_LINK:
        case SIGNAL_TYPE_DVI_DUAL_LINK:
        case SIGNAL_TYPE_HDMI_TYPE_A:
                ret = (link->hdcp_caps.rx_caps.fields.version == 0x4) ? 1:0;
                break;
        default:
                break;
        }

        return ret;
}

static void query_hdcp_capability(enum signal_type signal, struct dc_link *link)
{
        struct hdcp_protection_message msg22;
        struct hdcp_protection_message msg14;

        memset(&msg22, 0, sizeof(struct hdcp_protection_message));
        memset(&msg14, 0, sizeof(struct hdcp_protection_message));
        memset(link->hdcp_caps.rx_caps.raw, 0,
                sizeof(link->hdcp_caps.rx_caps.raw));

        if ((link->connector_signal == SIGNAL_TYPE_DISPLAY_PORT &&
                        link->ddc->transaction_type ==
                        DDC_TRANSACTION_TYPE_I2C_OVER_AUX) ||
                        link->connector_signal == SIGNAL_TYPE_EDP) {
                msg22.data = link->hdcp_caps.rx_caps.raw;
                msg22.length = sizeof(link->hdcp_caps.rx_caps.raw);
                msg22.msg_id = HDCP_MESSAGE_ID_RX_CAPS;
        } else {
                msg22.data = &link->hdcp_caps.rx_caps.fields.version;
                msg22.length = sizeof(link->hdcp_caps.rx_caps.fields.version);
                msg22.msg_id = HDCP_MESSAGE_ID_HDCP2VERSION;
        }
        msg22.version = HDCP_VERSION_22;
        msg22.link = HDCP_LINK_PRIMARY;
        msg22.max_retries = 5;
        dc_process_hdcp_msg(signal, link, &msg22);

        if (signal == SIGNAL_TYPE_DISPLAY_PORT || signal == SIGNAL_TYPE_DISPLAY_PORT_MST) {
                msg14.data = &link->hdcp_caps.bcaps.raw;
                msg14.length = sizeof(link->hdcp_caps.bcaps.raw);
                msg14.msg_id = HDCP_MESSAGE_ID_READ_BCAPS;
                msg14.version = HDCP_VERSION_14;
                msg14.link = HDCP_LINK_PRIMARY;
                msg14.max_retries = 5;

                dc_process_hdcp_msg(signal, link, &msg14);
        }

}
#endif

static void read_current_link_settings_on_detect(struct dc_link *link)
{
        union lane_count_set lane_count_set = { {0} };
        uint8_t link_bw_set;
        uint8_t link_rate_set;
        uint32_t read_dpcd_retry_cnt = 10;
        enum dc_status status = DC_ERROR_UNEXPECTED;
        int i;
        union max_down_spread max_down_spread = { {0} };

        // Read DPCD 00101h to find out the number of lanes currently set
        for (i = 0; i < read_dpcd_retry_cnt; i++) {
                status = core_link_read_dpcd(link,
                                             DP_LANE_COUNT_SET,
                                             &lane_count_set.raw,
                                             sizeof(lane_count_set));
                /* First DPCD read after VDD ON can fail if the particular board
                 * does not have HPD pin wired correctly. So if DPCD read fails,
                 * which it should never happen, retry a few times. Target worst
                 * case scenario of 80 ms.
                 */
                if (status == DC_OK) {
                        link->cur_link_settings.lane_count =
                                        lane_count_set.bits.LANE_COUNT_SET;
                        break;
                }

                msleep(8);
        }

        // Read DPCD 00100h to find if standard link rates are set
        core_link_read_dpcd(link, DP_LINK_BW_SET,
                            &link_bw_set, sizeof(link_bw_set));

        if (link_bw_set == 0) {
                if (link->connector_signal == SIGNAL_TYPE_EDP) {
                        /* If standard link rates are not being used,
                         * Read DPCD 00115h to find the edp link rate set used
                         */
                        core_link_read_dpcd(link, DP_LINK_RATE_SET,
                                            &link_rate_set, sizeof(link_rate_set));

                        // edp_supported_link_rates_count = 0 for DP
                        if (link_rate_set < link->dpcd_caps.edp_supported_link_rates_count) {
                                link->cur_link_settings.link_rate =
                                        link->dpcd_caps.edp_supported_link_rates[link_rate_set];
                                link->cur_link_settings.link_rate_set = link_rate_set;
                                link->cur_link_settings.use_link_rate_set = true;
                        }
                } else {
                        // Link Rate not found. Seamless boot may not work.
                        ASSERT(false);
                }
        } else {
                link->cur_link_settings.link_rate = link_bw_set;
                link->cur_link_settings.use_link_rate_set = false;
        }
        // Read DPCD 00003h to find the max down spread.
        core_link_read_dpcd(link, DP_MAX_DOWNSPREAD,
                            &max_down_spread.raw, sizeof(max_down_spread));
        link->cur_link_settings.link_spread =
                max_down_spread.bits.MAX_DOWN_SPREAD ?
                LINK_SPREAD_05_DOWNSPREAD_30KHZ : LINK_SPREAD_DISABLED;
}

static bool detect_dp(struct dc_link *link,
                      struct display_sink_capability *sink_caps,
                      enum dc_detect_reason reason)
{
        struct audio_support *audio_support = &link->dc->res_pool->audio_support;

        sink_caps->signal = link_detect_sink(link, reason);
        sink_caps->transaction_type =
                get_ddc_transaction_type(sink_caps->signal);

        if (sink_caps->transaction_type == DDC_TRANSACTION_TYPE_I2C_OVER_AUX) {
                sink_caps->signal = SIGNAL_TYPE_DISPLAY_PORT;
                if (!detect_dp_sink_caps(link))
                        return false;
                if (is_mst_supported(link)) {
                        sink_caps->signal = SIGNAL_TYPE_DISPLAY_PORT_MST;
                        link->type = dc_connection_mst_branch;

                        dal_ddc_service_set_transaction_type(link->ddc,
                                                             sink_caps->transaction_type);

#if defined(CONFIG_DRM_AMD_DC_HDCP)
                        /* In case of fallback to SST when topology discovery below fails
                         * HDCP caps will be querried again later by the upper layer (caller
                         * of this function). */
                        query_hdcp_capability(SIGNAL_TYPE_DISPLAY_PORT_MST, link);
#endif
                }

                if (link->type != dc_connection_mst_branch &&
                                is_dp_branch_device(link))
                        /* DP SST branch */
                        link->type = dc_connection_sst_branch;
        } else {
                /* DP passive dongles */
                sink_caps->signal = dp_passive_dongle_detection(link->ddc,
                                                                sink_caps,
                                                                audio_support);
                link->dpcd_caps.dongle_type = sink_caps->dongle_type;
        }

        return true;
}

static bool is_same_edid(struct dc_edid *old_edid, struct dc_edid *new_edid)
{
        if (old_edid->length != new_edid->length)
                return false;

        if (new_edid->length == 0)
                return false;

        return (memcmp(old_edid->raw_edid,
                       new_edid->raw_edid, new_edid->length) == 0);
}

static bool wait_for_entering_dp_alt_mode(struct dc_link *link)
{
        /**
         * something is terribly wrong if time out is > 200ms. (5Hz)
         * 500 microseconds * 400 tries us 200 ms
         **/
        unsigned int sleep_time_in_microseconds = 500;
        unsigned int tries_allowed = 400;
        bool is_in_alt_mode;
        unsigned long long enter_timestamp;
        unsigned long long finish_timestamp;
        unsigned long long time_taken_in_ns;
        int tries_taken;

        DC_LOGGER_INIT(link->ctx->logger);

        if (!link->link_enc->funcs->is_in_alt_mode)
                return true;

        is_in_alt_mode = link->link_enc->funcs->is_in_alt_mode(link->link_enc);
        DC_LOG_WARNING("DP Alt mode state on HPD: %d\n", is_in_alt_mode);

        if (is_in_alt_mode)
                return true;

        enter_timestamp = dm_get_timestamp(link->ctx);

        for (tries_taken = 0; tries_taken < tries_allowed; tries_taken++) {
                udelay(sleep_time_in_microseconds);
                /* ask the link if alt mode is enabled, if so return ok */
                if (link->link_enc->funcs->is_in_alt_mode(link->link_enc)) {
                        finish_timestamp = dm_get_timestamp(link->ctx);
                        time_taken_in_ns =
                                dm_get_elapse_time_in_ns(link->ctx,
                                                         finish_timestamp,
                                                         enter_timestamp);
                        DC_LOG_WARNING("Alt mode entered finished after %llu ms\n",
                                       div_u64(time_taken_in_ns, 1000000));
                        return true;
                }
        }
        finish_timestamp = dm_get_timestamp(link->ctx);
        time_taken_in_ns = dm_get_elapse_time_in_ns(link->ctx, finish_timestamp,
                                                    enter_timestamp);
        DC_LOG_WARNING("Alt mode has timed out after %llu ms\n",
                       div_u64(time_taken_in_ns, 1000000));
        return false;
}

/*
 * dc_link_detect() - Detect if a sink is attached to a given link
 *
 * link->local_sink is created or destroyed as needed.
 *
 * This does not create remote sinks but will trigger DM
 * to start MST detection if a branch is detected.
 */
static bool dc_link_detect_helper(struct dc_link *link,
                                  enum dc_detect_reason reason)
{
        struct dc_sink_init_data sink_init_data = { 0 };
        struct display_sink_capability sink_caps = { 0 };
        uint32_t i;
        bool converter_disable_audio = false;
        struct audio_support *aud_support = &link->dc->res_pool->audio_support;
        bool same_edid = false;
        enum dc_edid_status edid_status;
        struct dc_context *dc_ctx = link->ctx;
        struct dc_sink *sink = NULL;
        struct dc_sink *prev_sink = NULL;
        struct dpcd_caps prev_dpcd_caps;
        enum dc_connection_type new_connection_type = dc_connection_none;
        enum dc_connection_type pre_connection_type = dc_connection_none;
        bool perform_dp_seamless_boot = false;
        const uint32_t post_oui_delay = 30; // 30ms

        DC_LOGGER_INIT(link->ctx->logger);

        if (dc_is_virtual_signal(link->connector_signal))
                return false;

        if (((link->connector_signal == SIGNAL_TYPE_LVDS ||
                link->connector_signal == SIGNAL_TYPE_EDP) &&
                (!link->dc->config.allow_edp_hotplug_detection)) &&
                link->local_sink) {
                // need to re-write OUI and brightness in resume case
                if (link->connector_signal == SIGNAL_TYPE_EDP) {
                        dpcd_set_source_specific_data(link);
                        msleep(post_oui_delay);
                        dc_link_set_default_brightness_aux(link);
                        //TODO: use cached
                }

                return true;
        }

        if (!dc_link_detect_sink(link, &new_connection_type)) {
                BREAK_TO_DEBUGGER();
                return false;
        }

        prev_sink = link->local_sink;
        if (prev_sink) {
                dc_sink_retain(prev_sink);
                memcpy(&prev_dpcd_caps, &link->dpcd_caps, sizeof(struct dpcd_caps));
        }

        link_disconnect_sink(link);
        if (new_connection_type != dc_connection_none) {
                pre_connection_type = link->type;
                link->type = new_connection_type;
                link->link_state_valid = false;

                /* From Disconnected-to-Connected. */
                switch (link->connector_signal) {
                case SIGNAL_TYPE_HDMI_TYPE_A: {
                        sink_caps.transaction_type = DDC_TRANSACTION_TYPE_I2C;
                        if (aud_support->hdmi_audio_native)
                                sink_caps.signal = SIGNAL_TYPE_HDMI_TYPE_A;
                        else
                                sink_caps.signal = SIGNAL_TYPE_DVI_SINGLE_LINK;
                        break;
                }

                case SIGNAL_TYPE_DVI_SINGLE_LINK: {
                        sink_caps.transaction_type = DDC_TRANSACTION_TYPE_I2C;
                        sink_caps.signal = SIGNAL_TYPE_DVI_SINGLE_LINK;
                        break;
                }

                case SIGNAL_TYPE_DVI_DUAL_LINK: {
                        sink_caps.transaction_type = DDC_TRANSACTION_TYPE_I2C;
                        sink_caps.signal = SIGNAL_TYPE_DVI_DUAL_LINK;
                        break;
                }

                case SIGNAL_TYPE_LVDS: {
                        sink_caps.transaction_type = DDC_TRANSACTION_TYPE_I2C;
                        sink_caps.signal = SIGNAL_TYPE_LVDS;
                        break;
                }

                case SIGNAL_TYPE_EDP: {
                        read_current_link_settings_on_detect(link);

                        detect_edp_sink_caps(link);
                        read_current_link_settings_on_detect(link);
                        sink_caps.transaction_type = DDC_TRANSACTION_TYPE_I2C_OVER_AUX;
                        sink_caps.signal = SIGNAL_TYPE_EDP;
                        break;
                }

                case SIGNAL_TYPE_DISPLAY_PORT: {
                        /* wa HPD high coming too early*/
                        if (link->ep_type == DISPLAY_ENDPOINT_PHY &&
                            link->link_enc->features.flags.bits.DP_IS_USB_C == 1) {
                                /* if alt mode times out, return false */
                                if (!wait_for_entering_dp_alt_mode(link))
                                        return false;
                        }

                        if (!detect_dp(link, &sink_caps, reason)) {
                                if (prev_sink)
                                        dc_sink_release(prev_sink);
                                return false;
                        }

                        if (link->type == dc_connection_mst_branch) {
                                LINK_INFO("link=%d, mst branch is now Connected\n",
                                          link->link_index);
                                /* Need to setup mst link_cap struct here
                                 * otherwise dc_link_detect() will leave mst link_cap
                                 * empty which leads to allocate_mst_payload() has "0"
                                 * pbn_per_slot value leading to exception on dc_fixpt_div()
                                 */
                                dp_verify_mst_link_cap(link);

                                /*
                                 * This call will initiate MST topology discovery. Which
                                 * will detect MST ports and add new DRM connector DRM
                                 * framework. Then read EDID via remote i2c over aux. In
                                 * the end, will notify DRM detect result and save EDID
                                 * into DRM framework.
                                 *
                                 * .detect is called by .fill_modes.
                                 * .fill_modes is called by user mode ioctl
                                 * DRM_IOCTL_MODE_GETCONNECTOR.
                                 *
                                 * .get_modes is called by .fill_modes.
                                 *
                                 * call .get_modes, AMDGPU DM implementation will create
                                 * new dc_sink and add to dc_link. For long HPD plug
                                 * in/out, MST has its own handle.
                                 *
                                 * Therefore, just after dc_create, link->sink is not
                                 * created for MST until user mode app calls
                                 * DRM_IOCTL_MODE_GETCONNECTOR.
                                 *
                                 * Need check ->sink usages in case ->sink = NULL
                                 * TODO: s3 resume check
                                 */

                                dm_helpers_dp_update_branch_info(link->ctx, link);
                                if (dm_helpers_dp_mst_start_top_mgr(link->ctx,
                                                link, reason == DETECT_REASON_BOOT)) {
                                        if (prev_sink)
                                                dc_sink_release(prev_sink);
                                        return false;
                                } else {
                                        link->type = dc_connection_sst_branch;
                                        sink_caps.signal = SIGNAL_TYPE_DISPLAY_PORT;
                                }
                        }

                        /* Active SST downstream branch device unplug*/
                        if (link->type == dc_connection_sst_branch &&
                            link->dpcd_caps.sink_count.bits.SINK_COUNT == 0) {
                                if (prev_sink)
                                        /* Downstream unplug */
                                        dc_sink_release(prev_sink);
                                return true;
                        }

                        /* disable audio for non DP to HDMI active sst converter */
                        if (link->type == dc_connection_sst_branch &&
                                        is_dp_active_dongle(link) &&
                                        (link->dpcd_caps.dongle_type !=
                                                        DISPLAY_DONGLE_DP_HDMI_CONVERTER))
                                converter_disable_audio = true;

                        // link switch from MST to non-MST stop topology manager
                        if (pre_connection_type == dc_connection_mst_branch &&
                                        link->type != dc_connection_mst_branch)
                                dm_helpers_dp_mst_stop_top_mgr(link->ctx, link);


                        // For seamless boot, to skip verify link cap, we read UEFI settings and set them as verified.
                        if (reason == DETECT_REASON_BOOT &&
                                        !dc_ctx->dc->config.power_down_display_on_boot &&

                                        link->link_status.link_active)
                                perform_dp_seamless_boot = true;

                        if (perform_dp_seamless_boot) {
                                read_current_link_settings_on_detect(link);
                                link->verified_link_cap = link->reported_link_cap;
                        }

                        break;
                }

                default:
                        DC_ERROR("Invalid connector type! signal:%d\n",
                                 link->connector_signal);
                        if (prev_sink)
                                dc_sink_release(prev_sink);
                        return false;
                } /* switch() */

                if (link->dpcd_caps.sink_count.bits.SINK_COUNT)
                        link->dpcd_sink_count =
                                link->dpcd_caps.sink_count.bits.SINK_COUNT;
                else
                        link->dpcd_sink_count = 1;

                dal_ddc_service_set_transaction_type(link->ddc,
                                                     sink_caps.transaction_type);

                link->aux_mode =
                        dal_ddc_service_is_in_aux_transaction_mode(link->ddc);

                sink_init_data.link = link;
                sink_init_data.sink_signal = sink_caps.signal;

                sink = dc_sink_create(&sink_init_data);
                if (!sink) {
                        DC_ERROR("Failed to create sink!\n");
                        if (prev_sink)
                                dc_sink_release(prev_sink);
                        return false;
                }

                sink->link->dongle_max_pix_clk = sink_caps.max_hdmi_pixel_clock;
                sink->converter_disable_audio = converter_disable_audio;

                /* dc_sink_create returns a new reference */
                link->local_sink = sink;

                edid_status = dm_helpers_read_local_edid(link->ctx,
                                                         link, sink);

                switch (edid_status) {
                case EDID_BAD_CHECKSUM:
                        DC_LOG_ERROR("EDID checksum invalid.\n");
                        break;
                case EDID_NO_RESPONSE:
                        DC_LOG_ERROR("No EDID read.\n");
                        /*
                         * Abort detection for non-DP connectors if we have
                         * no EDID
                         *
                         * DP needs to report as connected if HDP is high
                         * even if we have no EDID in order to go to
                         * fail-safe mode
                         */
                        if (dc_is_hdmi_signal(link->connector_signal) ||
                            dc_is_dvi_signal(link->connector_signal)) {
                                if (prev_sink)
                                        dc_sink_release(prev_sink);

                                return false;
                        }
                        break;
                default:
                        break;
                }

                // Check if edid is the same
                if ((prev_sink) &&
                    (edid_status == EDID_THE_SAME || edid_status == EDID_OK))
                        same_edid = is_same_edid(&prev_sink->dc_edid,
                                                 &sink->dc_edid);

                if (sink->edid_caps.panel_patch.skip_scdc_overwrite)
                        link->ctx->dc->debug.hdmi20_disable = true;

                if (link->connector_signal == SIGNAL_TYPE_DISPLAY_PORT &&
                    sink_caps.transaction_type ==
                    DDC_TRANSACTION_TYPE_I2C_OVER_AUX) {
                        /*
                         * TODO debug why Dell 2413 doesn't like
                         *  two link trainings
                         */
#if defined(CONFIG_DRM_AMD_DC_HDCP)
                        query_hdcp_capability(sink->sink_signal, link);
#endif

                        // verify link cap for SST non-seamless boot
                        if (!perform_dp_seamless_boot)
                                dp_verify_link_cap_with_retries(link,
                                                                &link->reported_link_cap,
                                                                LINK_TRAINING_MAX_VERIFY_RETRY);
                } else {
                        // If edid is the same, then discard new sink and revert back to original sink
                        if (same_edid) {
                                link_disconnect_remap(prev_sink, link);
                                sink = prev_sink;
                                prev_sink = NULL;
                        }
#if defined(CONFIG_DRM_AMD_DC_HDCP)
                        query_hdcp_capability(sink->sink_signal, link);
#endif
                }

                /* HDMI-DVI Dongle */
                if (sink->sink_signal == SIGNAL_TYPE_HDMI_TYPE_A &&
                    !sink->edid_caps.edid_hdmi)
                        sink->sink_signal = SIGNAL_TYPE_DVI_SINGLE_LINK;

                /* Connectivity log: detection */
                for (i = 0; i < sink->dc_edid.length / DC_EDID_BLOCK_SIZE; i++) {
                        CONN_DATA_DETECT(link,
                                         &sink->dc_edid.raw_edid[i * DC_EDID_BLOCK_SIZE],
                                         DC_EDID_BLOCK_SIZE,
                                         "%s: [Block %d] ", sink->edid_caps.display_name, i);
                }

                DC_LOG_DETECTION_EDID_PARSER("%s: "
                        "manufacturer_id = %X, "
                        "product_id = %X, "
                        "serial_number = %X, "
                        "manufacture_week = %d, "
                        "manufacture_year = %d, "
                        "display_name = %s, "
                        "speaker_flag = %d, "
                        "audio_mode_count = %d\n",
                        __func__,
                        sink->edid_caps.manufacturer_id,
                        sink->edid_caps.product_id,
                        sink->edid_caps.serial_number,
                        sink->edid_caps.manufacture_week,
                        sink->edid_caps.manufacture_year,
                        sink->edid_caps.display_name,
                        sink->edid_caps.speaker_flags,
                        sink->edid_caps.audio_mode_count);

                for (i = 0; i < sink->edid_caps.audio_mode_count; i++) {
                        DC_LOG_DETECTION_EDID_PARSER("%s: mode number = %d, "
                                "format_code = %d, "
                                "channel_count = %d, "
                                "sample_rate = %d, "
                                "sample_size = %d\n",
                                __func__,
                                i,
                                sink->edid_caps.audio_modes[i].format_code,
                                sink->edid_caps.audio_modes[i].channel_count,
                                sink->edid_caps.audio_modes[i].sample_rate,
                                sink->edid_caps.audio_modes[i].sample_size);
                }
        } else {
                /* From Connected-to-Disconnected. */
                if (link->type == dc_connection_mst_branch) {
                        LINK_INFO("link=%d, mst branch is now Disconnected\n",
                                  link->link_index);

                        dm_helpers_dp_mst_stop_top_mgr(link->ctx, link);

                        link->mst_stream_alloc_table.stream_count = 0;
                        memset(link->mst_stream_alloc_table.stream_allocations,
                               0,
                               sizeof(link->mst_stream_alloc_table.stream_allocations));
                }

                link->type = dc_connection_none;
                sink_caps.signal = SIGNAL_TYPE_NONE;
                /* When we unplug a passive DP-HDMI dongle connection, dongle_max_pix_clk
                 *  is not cleared. If we emulate a DP signal on this connection, it thinks
                 *  the dongle is still there and limits the number of modes we can emulate.
                 *  Clear dongle_max_pix_clk on disconnect to fix this
                 */
                link->dongle_max_pix_clk = 0;
        }

        LINK_INFO("link=%d, dc_sink_in=%p is now %s prev_sink=%p edid same=%d\n",
                  link->link_index, sink,
                  (sink_caps.signal ==
                   SIGNAL_TYPE_NONE ? "Disconnected" : "Connected"),
                  prev_sink, same_edid);

        if (prev_sink)
                dc_sink_release(prev_sink);

        return true;
}

bool dc_link_detect(struct dc_link *link, enum dc_detect_reason reason)
{
        const struct dc *dc = link->dc;
        bool ret;
        bool can_apply_seamless_boot = false;
        int i;

        for (i = 0; i < dc->current_state->stream_count; i++) {
                if (dc->current_state->streams[i]->apply_seamless_boot_optimization) {
                        can_apply_seamless_boot = true;
                        break;
                }
        }

        /* get out of low power state */
        if (!can_apply_seamless_boot && reason != DETECT_REASON_BOOT)
                clk_mgr_exit_optimized_pwr_state(dc, dc->clk_mgr);

        ret = dc_link_detect_helper(link, reason);

        /* Go back to power optimized state */
        if (!can_apply_seamless_boot && reason != DETECT_REASON_BOOT)
                clk_mgr_optimize_pwr_state(dc, dc->clk_mgr);

        return ret;
}

bool dc_link_get_hpd_state(struct dc_link *dc_link)
{
        uint32_t state;

        dal_gpio_lock_pin(dc_link->hpd_gpio);
        dal_gpio_get_value(dc_link->hpd_gpio, &state);
        dal_gpio_unlock_pin(dc_link->hpd_gpio);

        return state;
}

static enum hpd_source_id get_hpd_line(struct dc_link *link)
{
        struct gpio *hpd;
        enum hpd_source_id hpd_id = HPD_SOURCEID_UNKNOWN;

        hpd = get_hpd_gpio(link->ctx->dc_bios, link->link_id,
                           link->ctx->gpio_service);

        if (hpd) {
                switch (dal_irq_get_source(hpd)) {
                case DC_IRQ_SOURCE_HPD1:
                        hpd_id = HPD_SOURCEID1;
                break;
                case DC_IRQ_SOURCE_HPD2:
                        hpd_id = HPD_SOURCEID2;
                break;
                case DC_IRQ_SOURCE_HPD3:
                        hpd_id = HPD_SOURCEID3;
                break;
                case DC_IRQ_SOURCE_HPD4:
                        hpd_id = HPD_SOURCEID4;
                break;
                case DC_IRQ_SOURCE_HPD5:
                        hpd_id = HPD_SOURCEID5;
                break;
                case DC_IRQ_SOURCE_HPD6:
                        hpd_id = HPD_SOURCEID6;
                break;
                default:
                        BREAK_TO_DEBUGGER();
                break;
                }

                dal_gpio_destroy_irq(&hpd);
        }

        return hpd_id;
}

static enum channel_id get_ddc_line(struct dc_link *link)
{
        struct ddc *ddc;
        enum channel_id channel = CHANNEL_ID_UNKNOWN;

        ddc = dal_ddc_service_get_ddc_pin(link->ddc);

        if (ddc) {
                switch (dal_ddc_get_line(ddc)) {
                case GPIO_DDC_LINE_DDC1:
                        channel = CHANNEL_ID_DDC1;
                        break;
                case GPIO_DDC_LINE_DDC2:
                        channel = CHANNEL_ID_DDC2;
                        break;
                case GPIO_DDC_LINE_DDC3:
                        channel = CHANNEL_ID_DDC3;
                        break;
                case GPIO_DDC_LINE_DDC4:
                        channel = CHANNEL_ID_DDC4;
                        break;
                case GPIO_DDC_LINE_DDC5:
                        channel = CHANNEL_ID_DDC5;
                        break;
                case GPIO_DDC_LINE_DDC6:
                        channel = CHANNEL_ID_DDC6;
                        break;
                case GPIO_DDC_LINE_DDC_VGA:
                        channel = CHANNEL_ID_DDC_VGA;
                        break;
                case GPIO_DDC_LINE_I2C_PAD:
                        channel = CHANNEL_ID_I2C_PAD;
                        break;
                default:
                        BREAK_TO_DEBUGGER();
                        break;
                }
        }

        return channel;
}

static enum transmitter translate_encoder_to_transmitter(struct graphics_object_id encoder)
{
        switch (encoder.id) {
        case ENCODER_ID_INTERNAL_UNIPHY:
                switch (encoder.enum_id) {
                case ENUM_ID_1:
                        return TRANSMITTER_UNIPHY_A;
                case ENUM_ID_2:
                        return TRANSMITTER_UNIPHY_B;
                default:
                        return TRANSMITTER_UNKNOWN;
                }
        break;
        case ENCODER_ID_INTERNAL_UNIPHY1:
                switch (encoder.enum_id) {
                case ENUM_ID_1:
                        return TRANSMITTER_UNIPHY_C;
                case ENUM_ID_2:
                        return TRANSMITTER_UNIPHY_D;
                default:
                        return TRANSMITTER_UNKNOWN;
                }
        break;
        case ENCODER_ID_INTERNAL_UNIPHY2:
                switch (encoder.enum_id) {
                case ENUM_ID_1:
                        return TRANSMITTER_UNIPHY_E;
                case ENUM_ID_2:
                        return TRANSMITTER_UNIPHY_F;
                default:
                        return TRANSMITTER_UNKNOWN;
                }
        break;
        case ENCODER_ID_INTERNAL_UNIPHY3:
                switch (encoder.enum_id) {
                case ENUM_ID_1:
                        return TRANSMITTER_UNIPHY_G;
                default:
                        return TRANSMITTER_UNKNOWN;
                }
        break;
        case ENCODER_ID_EXTERNAL_NUTMEG:
                switch (encoder.enum_id) {
                case ENUM_ID_1:
                        return TRANSMITTER_NUTMEG_CRT;
                default:
                        return TRANSMITTER_UNKNOWN;
                }
        break;
        case ENCODER_ID_EXTERNAL_TRAVIS:
                switch (encoder.enum_id) {
                case ENUM_ID_1:
                        return TRANSMITTER_TRAVIS_CRT;
                case ENUM_ID_2:
                        return TRANSMITTER_TRAVIS_LCD;
                default:
                        return TRANSMITTER_UNKNOWN;
                }
        break;
        default:
                return TRANSMITTER_UNKNOWN;
        }
}

static bool dc_link_construct(struct dc_link *link,
                              const struct link_init_data *init_params)
{
        uint8_t i;
        struct ddc_service_init_data ddc_service_init_data = { { 0 } };
        struct dc_context *dc_ctx = init_params->ctx;
        struct encoder_init_data enc_init_data = { 0 };
        struct panel_cntl_init_data panel_cntl_init_data = { 0 };
        struct integrated_info *info;
        struct dc_bios *bios = init_params->dc->ctx->dc_bios;
        const struct dc_vbios_funcs *bp_funcs = bios->funcs;
        struct bp_disp_connector_caps_info disp_connect_caps_info = { 0 };

        DC_LOGGER_INIT(dc_ctx->logger);

        info = kzalloc(sizeof(*info), GFP_KERNEL);
        if (!info)
                goto create_fail;

        link->irq_source_hpd = DC_IRQ_SOURCE_INVALID;
        link->irq_source_hpd_rx = DC_IRQ_SOURCE_INVALID;

        link->link_status.dpcd_caps = &link->dpcd_caps;

        link->dc = init_params->dc;
        link->ctx = dc_ctx;
        link->link_index = init_params->link_index;

        memset(&link->preferred_training_settings, 0,
               sizeof(struct dc_link_training_overrides));
        memset(&link->preferred_link_setting, 0,
               sizeof(struct dc_link_settings));

        link->link_id =
                bios->funcs->get_connector_id(bios, init_params->connector_index);

        link->ep_type = DISPLAY_ENDPOINT_PHY;

        DC_LOG_DC("BIOS object table - link_id: %d", link->link_id.id);

        if (bios->funcs->get_disp_connector_caps_info) {
                bios->funcs->get_disp_connector_caps_info(bios, link->link_id, &disp_connect_caps_info);
                link->is_internal_display = disp_connect_caps_info.INTERNAL_DISPLAY;
                DC_LOG_DC("BIOS object table - is_internal_display: %d", link->is_internal_display);
        }

        if (link->link_id.type != OBJECT_TYPE_CONNECTOR) {
                dm_output_to_console("%s: Invalid Connector ObjectID from Adapter Service for connector index:%d! type %d expected %d\n",
                                     __func__, init_params->connector_index,
                                     link->link_id.type, OBJECT_TYPE_CONNECTOR);
                goto create_fail;
        }

        if (link->dc->res_pool->funcs->link_init)
                link->dc->res_pool->funcs->link_init(link);

        link->hpd_gpio = get_hpd_gpio(link->ctx->dc_bios, link->link_id,
                                      link->ctx->gpio_service);

        if (link->hpd_gpio) {
                dal_gpio_open(link->hpd_gpio, GPIO_MODE_INTERRUPT);
                dal_gpio_unlock_pin(link->hpd_gpio);
                link->irq_source_hpd = dal_irq_get_source(link->hpd_gpio);

                DC_LOG_DC("BIOS object table - hpd_gpio id: %d", link->hpd_gpio->id);
                DC_LOG_DC("BIOS object table - hpd_gpio en: %d", link->hpd_gpio->en);
        }

        switch (link->link_id.id) {
        case CONNECTOR_ID_HDMI_TYPE_A:
                link->connector_signal = SIGNAL_TYPE_HDMI_TYPE_A;

                break;
        case CONNECTOR_ID_SINGLE_LINK_DVID:
        case CONNECTOR_ID_SINGLE_LINK_DVII:
                link->connector_signal = SIGNAL_TYPE_DVI_SINGLE_LINK;
                break;
        case CONNECTOR_ID_DUAL_LINK_DVID:
        case CONNECTOR_ID_DUAL_LINK_DVII:
                link->connector_signal = SIGNAL_TYPE_DVI_DUAL_LINK;
                break;
        case CONNECTOR_ID_DISPLAY_PORT:
                link->connector_signal = SIGNAL_TYPE_DISPLAY_PORT;

                if (link->hpd_gpio)
                        link->irq_source_hpd_rx =
                                        dal_irq_get_rx_source(link->hpd_gpio);

                break;
        case CONNECTOR_ID_EDP:
                link->connector_signal = SIGNAL_TYPE_EDP;

                if (link->hpd_gpio) {
                        if (!link->dc->config.allow_edp_hotplug_detection)
                                link->irq_source_hpd = DC_IRQ_SOURCE_INVALID;
                        link->irq_source_hpd_rx =
                                        dal_irq_get_rx_source(link->hpd_gpio);
                }

                break;
        case CONNECTOR_ID_LVDS:
                link->connector_signal = SIGNAL_TYPE_LVDS;
                break;
        default:
                DC_LOG_WARNING("Unsupported Connector type:%d!\n",
                               link->link_id.id);
                goto create_fail;
        }

        /* TODO: #DAL3 Implement id to str function.*/
        LINK_INFO("Connector[%d] description:"
                  "signal %d\n",
                  init_params->connector_index,
                  link->connector_signal);

        ddc_service_init_data.ctx = link->ctx;
        ddc_service_init_data.id = link->link_id;
        ddc_service_init_data.link = link;
        link->ddc = dal_ddc_service_create(&ddc_service_init_data);

        if (!link->ddc) {
                DC_ERROR("Failed to create ddc_service!\n");
                goto ddc_create_fail;
        }

        if (!link->ddc->ddc_pin) {
                DC_ERROR("Failed to get I2C info for connector!\n");
                goto ddc_create_fail;
        }

        link->ddc_hw_inst =
                dal_ddc_get_line(dal_ddc_service_get_ddc_pin(link->ddc));


        if (link->dc->res_pool->funcs->panel_cntl_create &&
                (link->link_id.id == CONNECTOR_ID_EDP ||
                        link->link_id.id == CONNECTOR_ID_LVDS)) {
                panel_cntl_init_data.ctx = dc_ctx;
                panel_cntl_init_data.inst =
                        panel_cntl_init_data.ctx->dc_edp_id_count;
                link->panel_cntl =
                        link->dc->res_pool->funcs->panel_cntl_create(
                                                                &panel_cntl_init_data);
                panel_cntl_init_data.ctx->dc_edp_id_count++;

                if (link->panel_cntl == NULL) {
                        DC_ERROR("Failed to create link panel_cntl!\n");
                        goto panel_cntl_create_fail;
                }
        }

        enc_init_data.ctx = dc_ctx;
        bp_funcs->get_src_obj(dc_ctx->dc_bios, link->link_id, 0,
                              &enc_init_data.encoder);
        enc_init_data.connector = link->link_id;
        enc_init_data.channel = get_ddc_line(link);
        enc_init_data.hpd_source = get_hpd_line(link);

        link->hpd_src = enc_init_data.hpd_source;

        enc_init_data.transmitter =
                translate_encoder_to_transmitter(enc_init_data.encoder);
        link->link_enc =
                link->dc->res_pool->funcs->link_enc_create(&enc_init_data);

        if (!link->link_enc) {
                DC_ERROR("Failed to create link encoder!\n");
                goto link_enc_create_fail;
        }

        DC_LOG_DC("BIOS object table - DP_IS_USB_C: %d", link->link_enc->features.flags.bits.DP_IS_USB_C);

        /* Update link encoder tracking variables. These are used for the dynamic
         * assignment of link encoders to streams.
         */
        link->eng_id = link->link_enc->preferred_engine;
        link->dc->res_pool->link_encoders[link->eng_id - ENGINE_ID_DIGA] = link->link_enc;
        link->dc->res_pool->dig_link_enc_count++;

        link->link_enc_hw_inst = link->link_enc->transmitter;

        for (i = 0; i < 4; i++) {
                if (bp_funcs->get_device_tag(dc_ctx->dc_bios,
                                             link->link_id, i,
                                             &link->device_tag) != BP_RESULT_OK) {
                        DC_ERROR("Failed to find device tag!\n");
                        goto device_tag_fail;
                }

                /* Look for device tag that matches connector signal,
                 * CRT for rgb, LCD for other supported signal tyes
                 */
                if (!bp_funcs->is_device_id_supported(dc_ctx->dc_bios,
                                                      link->device_tag.dev_id))
                        continue;
                if (link->device_tag.dev_id.device_type == DEVICE_TYPE_CRT &&
                    link->connector_signal != SIGNAL_TYPE_RGB)
                        continue;
                if (link->device_tag.dev_id.device_type == DEVICE_TYPE_LCD &&
                    link->connector_signal == SIGNAL_TYPE_RGB)
                        continue;

                DC_LOG_DC("BIOS object table - device_tag.acpi_device: %d", link->device_tag.acpi_device);
                DC_LOG_DC("BIOS object table - device_tag.dev_id.device_type: %d", link->device_tag.dev_id.device_type);
                DC_LOG_DC("BIOS object table - device_tag.dev_id.enum_id: %d", link->device_tag.dev_id.enum_id);
                break;
        }

        if (bios->integrated_info)
                memcpy(info, bios->integrated_info, sizeof(*info));

        /* Look for channel mapping corresponding to connector and device tag */
        for (i = 0; i < MAX_NUMBER_OF_EXT_DISPLAY_PATH; i++) {
                struct external_display_path *path =
                        &info->ext_disp_conn_info.path[i];

                if (path->device_connector_id.enum_id == link->link_id.enum_id &&
                    path->device_connector_id.id == link->link_id.id &&
                    path->device_connector_id.type == link->link_id.type) {
                        if (link->device_tag.acpi_device != 0 &&
                            path->device_acpi_enum == link->device_tag.acpi_device) {
                                link->ddi_channel_mapping = path->channel_mapping;
                                link->chip_caps = path->caps;
                                DC_LOG_DC("BIOS object table - ddi_channel_mapping: 0x%04X", link->ddi_channel_mapping.raw);
                                DC_LOG_DC("BIOS object table - chip_caps: %d", link->chip_caps);
                        } else if (path->device_tag ==
                                   link->device_tag.dev_id.raw_device_tag) {
                                link->ddi_channel_mapping = path->channel_mapping;
                                link->chip_caps = path->caps;
                                DC_LOG_DC("BIOS object table - ddi_channel_mapping: 0x%04X", link->ddi_channel_mapping.raw);
                                DC_LOG_DC("BIOS object table - chip_caps: %d", link->chip_caps);
                        }
                        break;
                }
        }

        if (bios->funcs->get_atom_dc_golden_table)
                bios->funcs->get_atom_dc_golden_table(bios);

        /*
         * TODO check if GPIO programmed correctly
         *
         * If GPIO isn't programmed correctly HPD might not rise or drain
         * fast enough, leading to bounces.
         */
        program_hpd_filter(link);

        link->psr_settings.psr_version = DC_PSR_VERSION_UNSUPPORTED;

        DC_LOG_DC("BIOS object table - %s finished successfully.\n", __func__);
        kfree(info);
        return true;
device_tag_fail:
        link->link_enc->funcs->destroy(&link->link_enc);
link_enc_create_fail:
        if (link->panel_cntl != NULL)
                link->panel_cntl->funcs->destroy(&link->panel_cntl);
panel_cntl_create_fail:
        dal_ddc_service_destroy(&link->ddc);
ddc_create_fail:
create_fail:

        if (link->hpd_gpio) {
                dal_gpio_destroy_irq(&link->hpd_gpio);
                link->hpd_gpio = NULL;
        }

        DC_LOG_DC("BIOS object table - %s failed.\n", __func__);
        kfree(info);

        return false;
}

/*******************************************************************************
 * Public functions
 ******************************************************************************/
struct dc_link *link_create(const struct link_init_data *init_params)
{
        struct dc_link *link =
                        kzalloc(sizeof(*link), GFP_KERNEL);

        if (NULL == link)
                goto alloc_fail;

        if (false == dc_link_construct(link, init_params))
                goto construct_fail;

        return link;

construct_fail:
        kfree(link);

alloc_fail:
        return NULL;
}

void link_destroy(struct dc_link **link)
{
        dc_link_destruct(*link);
        kfree(*link);
        *link = NULL;
}

static void enable_stream_features(struct pipe_ctx *pipe_ctx)
{
        struct dc_stream_state *stream = pipe_ctx->stream;

        if (pipe_ctx->stream->signal != SIGNAL_TYPE_DISPLAY_PORT_MST) {
                struct dc_link *link = stream->link;
                union down_spread_ctrl old_downspread;
                union down_spread_ctrl new_downspread;

                core_link_read_dpcd(link, DP_DOWNSPREAD_CTRL,
                                &old_downspread.raw, sizeof(old_downspread));

                new_downspread.raw = old_downspread.raw;

                new_downspread.bits.IGNORE_MSA_TIMING_PARAM =
                                (stream->ignore_msa_timing_param) ? 1 : 0;

                if (new_downspread.raw != old_downspread.raw) {
                        core_link_write_dpcd(link, DP_DOWNSPREAD_CTRL,
                                &new_downspread.raw, sizeof(new_downspread));
                }

        } else {
                dm_helpers_mst_enable_stream_features(stream);
        }
}

static enum dc_status enable_link_dp(struct dc_state *state,
                                     struct pipe_ctx *pipe_ctx)
{
        struct dc_stream_state *stream = pipe_ctx->stream;
        enum dc_status status;
        bool skip_video_pattern;
        struct dc_link *link = stream->link;
        struct dc_link_settings link_settings = {0};
        bool fec_enable;
        int i;
        bool apply_seamless_boot_optimization = false;
        uint32_t bl_oled_enable_delay = 50; // in ms
        const uint32_t post_oui_delay = 30; // 30ms
        /* Reduce link bandwidth between failed link training attempts. */
        bool do_fallback = false;

        // check for seamless boot
        for (i = 0; i < state->stream_count; i++) {
                if (state->streams[i]->apply_seamless_boot_optimization) {
                        apply_seamless_boot_optimization = true;
                        break;
                }
        }

        /* get link settings for video mode timing */
        decide_link_settings(stream, &link_settings);

        if (pipe_ctx->stream->signal == SIGNAL_TYPE_EDP) {
                /*in case it is not on*/
                link->dc->hwss.edp_power_control(link, true);
                link->dc->hwss.edp_wait_for_hpd_ready(link, true);
        }

        pipe_ctx->stream_res.pix_clk_params.requested_sym_clk =
                        link_settings.link_rate * LINK_RATE_REF_FREQ_IN_KHZ;
        if (state->clk_mgr && !apply_seamless_boot_optimization)
                state->clk_mgr->funcs->update_clocks(state->clk_mgr,
                                                     state, false);

        // during mode switch we do DP_SET_POWER off then on, and OUI is lost
        dpcd_set_source_specific_data(link);
        if (link->dpcd_sink_ext_caps.raw != 0)
                msleep(post_oui_delay);

        skip_video_pattern = true;

        if (link_settings.link_rate == LINK_RATE_LOW)
                skip_video_pattern = false;

        if (perform_link_training_with_retries(&link_settings,
                                               skip_video_pattern,
                                               LINK_TRAINING_ATTEMPTS,
                                               pipe_ctx,
                                               pipe_ctx->stream->signal,
                                               do_fallback)) {
                link->cur_link_settings = link_settings;
                status = DC_OK;
        } else {
                status = DC_FAIL_DP_LINK_TRAINING;
        }

        if (link->preferred_training_settings.fec_enable)
                fec_enable = *link->preferred_training_settings.fec_enable;
        else
                fec_enable = true;

        dp_set_fec_enable(link, fec_enable);

        // during mode set we do DP_SET_POWER off then on, aux writes are lost
        if (link->dpcd_sink_ext_caps.bits.oled == 1 ||
                link->dpcd_sink_ext_caps.bits.sdr_aux_backlight_control == 1 ||
                link->dpcd_sink_ext_caps.bits.hdr_aux_backlight_control == 1) {
                dc_link_set_default_brightness_aux(link); // TODO: use cached if known
                if (link->dpcd_sink_ext_caps.bits.oled == 1)
                        msleep(bl_oled_enable_delay);
                dc_link_backlight_enable_aux(link, true);
        }

        return status;
}

static enum dc_status enable_link_edp(
                struct dc_state *state,
                struct pipe_ctx *pipe_ctx)
{
        enum dc_status status;

        status = enable_link_dp(state, pipe_ctx);

        return status;
}

static enum dc_status enable_link_dp_mst(
                struct dc_state *state,
                struct pipe_ctx *pipe_ctx)
{
        struct dc_link *link = pipe_ctx->stream->link;

        /* sink signal type after MST branch is MST. Multiple MST sinks
         * share one link. Link DP PHY is enable or training only once.
         */
        if (link->link_status.link_active)
                return DC_OK;

        /* clear payload table */
        dm_helpers_dp_mst_clear_payload_allocation_table(link->ctx, link);

        /* to make sure the pending down rep can be processed
         * before enabling the link
         */
        dm_helpers_dp_mst_poll_pending_down_reply(link->ctx, link);

        /* set the sink to MST mode before enabling the link */
        dp_enable_mst_on_sink(link, true);

        return enable_link_dp(state, pipe_ctx);
}

static bool get_ext_hdmi_settings(struct pipe_ctx *pipe_ctx,
                enum engine_id eng_id,
                struct ext_hdmi_settings *settings)
{
        bool result = false;
        int i = 0;
        struct integrated_info *integrated_info =
                        pipe_ctx->stream->ctx->dc_bios->integrated_info;

        if (integrated_info == NULL)
                return false;

        /*
         * Get retimer settings from sbios for passing SI eye test for DCE11
         * The setting values are varied based on board revision and port id
         * Therefore the setting values of each ports is passed by sbios.
         */

        // Check if current bios contains ext Hdmi settings
        if (integrated_info->gpu_cap_info & 0x20) {
                switch (eng_id) {
                case ENGINE_ID_DIGA:
                        settings->slv_addr = integrated_info->dp0_ext_hdmi_slv_addr;
                        settings->reg_num = integrated_info->dp0_ext_hdmi_6g_reg_num;
                        settings->reg_num_6g = integrated_info->dp0_ext_hdmi_6g_reg_num;
                        memmove(settings->reg_settings,
                                        integrated_info->dp0_ext_hdmi_reg_settings,
                                        sizeof(integrated_info->dp0_ext_hdmi_reg_settings));
                        memmove(settings->reg_settings_6g,
                                        integrated_info->dp0_ext_hdmi_6g_reg_settings,
                                        sizeof(integrated_info->dp0_ext_hdmi_6g_reg_settings));
                        result = true;
                        break;
                case ENGINE_ID_DIGB:
                        settings->slv_addr = integrated_info->dp1_ext_hdmi_slv_addr;
                        settings->reg_num = integrated_info->dp1_ext_hdmi_6g_reg_num;
                        settings->reg_num_6g = integrated_info->dp1_ext_hdmi_6g_reg_num;
                        memmove(settings->reg_settings,
                                        integrated_info->dp1_ext_hdmi_reg_settings,
                                        sizeof(integrated_info->dp1_ext_hdmi_reg_settings));
                        memmove(settings->reg_settings_6g,
                                        integrated_info->dp1_ext_hdmi_6g_reg_settings,
                                        sizeof(integrated_info->dp1_ext_hdmi_6g_reg_settings));
                        result = true;
                        break;
                case ENGINE_ID_DIGC:
                        settings->slv_addr = integrated_info->dp2_ext_hdmi_slv_addr;
                        settings->reg_num = integrated_info->dp2_ext_hdmi_6g_reg_num;
                        settings->reg_num_6g = integrated_info->dp2_ext_hdmi_6g_reg_num;
                        memmove(settings->reg_settings,
                                        integrated_info->dp2_ext_hdmi_reg_settings,
                                        sizeof(integrated_info->dp2_ext_hdmi_reg_settings));
                        memmove(settings->reg_settings_6g,
                                        integrated_info->dp2_ext_hdmi_6g_reg_settings,
                                        sizeof(integrated_info->dp2_ext_hdmi_6g_reg_settings));
                        result = true;
                        break;
                case ENGINE_ID_DIGD:
                        settings->slv_addr = integrated_info->dp3_ext_hdmi_slv_addr;
                        settings->reg_num = integrated_info->dp3_ext_hdmi_6g_reg_num;
                        settings->reg_num_6g = integrated_info->dp3_ext_hdmi_6g_reg_num;
                        memmove(settings->reg_settings,
                                        integrated_info->dp3_ext_hdmi_reg_settings,
                                        sizeof(integrated_info->dp3_ext_hdmi_reg_settings));
                        memmove(settings->reg_settings_6g,
                                        integrated_info->dp3_ext_hdmi_6g_reg_settings,
                                        sizeof(integrated_info->dp3_ext_hdmi_6g_reg_settings));
                        result = true;
                        break;
                default:
                        break;
                }

                if (result == true) {
                        // Validate settings from bios integrated info table
                        if (settings->slv_addr == 0)
                                return false;
                        if (settings->reg_num > 9)
                                return false;
                        if (settings->reg_num_6g > 3)
                                return false;

                        for (i = 0; i < settings->reg_num; i++) {
                                if (settings->reg_settings[i].i2c_reg_index > 0x20)
                                        return false;
                        }

                        for (i = 0; i < settings->reg_num_6g; i++) {
                                if (settings->reg_settings_6g[i].i2c_reg_index > 0x20)
                                        return false;
                        }
                }
        }

        return result;
}

static bool i2c_write(struct pipe_ctx *pipe_ctx,
                uint8_t address, uint8_t *buffer, uint32_t length)
{
        struct i2c_command cmd = {0};
        struct i2c_payload payload = {0};

        memset(&payload, 0, sizeof(payload));
        memset(&cmd, 0, sizeof(cmd));

        cmd.number_of_payloads = 1;
        cmd.engine = I2C_COMMAND_ENGINE_DEFAULT;
        cmd.speed = pipe_ctx->stream->ctx->dc->caps.i2c_speed_in_khz;

        payload.address = address;
        payload.data = buffer;
        payload.length = length;
        payload.write = true;
        cmd.payloads = &payload;

        if (dm_helpers_submit_i2c(pipe_ctx->stream->ctx,
                        pipe_ctx->stream->link, &cmd))
                return true;

        return false;
}

static void write_i2c_retimer_setting(
                struct pipe_ctx *pipe_ctx,
                bool is_vga_mode,
                bool is_over_340mhz,
                struct ext_hdmi_settings *settings)
{
        uint8_t slave_address = (settings->slv_addr >> 1);
        uint8_t buffer[2];
        const uint8_t apply_rx_tx_change = 0x4;
        uint8_t offset = 0xA;
        uint8_t value = 0;
        int i = 0;
        bool i2c_success = false;
        DC_LOGGER_INIT(pipe_ctx->stream->ctx->logger);

        memset(&buffer, 0, sizeof(buffer));

        /* Start Ext-Hdmi programming*/

        for (i = 0; i < settings->reg_num; i++) {
                /* Apply 3G settings */
                if (settings->reg_settings[i].i2c_reg_index <= 0x20) {

                        buffer[0] = settings->reg_settings[i].i2c_reg_index;
                        buffer[1] = settings->reg_settings[i].i2c_reg_val;
                        i2c_success = i2c_write(pipe_ctx, slave_address,
                                                buffer, sizeof(buffer));
                        RETIMER_REDRIVER_INFO("retimer write to slave_address = 0x%x,\
                                offset = 0x%x, reg_val= 0x%x, i2c_success = %d\n",
                                slave_address, buffer[0], buffer[1], i2c_success?1:0);

                        if (!i2c_success)
                                goto i2c_write_fail;

                        /* Based on DP159 specs, APPLY_RX_TX_CHANGE bit in 0x0A
                         * needs to be set to 1 on every 0xA-0xC write.
                         */
                        if (settings->reg_settings[i].i2c_reg_index == 0xA ||
                                settings->reg_settings[i].i2c_reg_index == 0xB ||
                                settings->reg_settings[i].i2c_reg_index == 0xC) {

                                /* Query current value from offset 0xA */
                                if (settings->reg_settings[i].i2c_reg_index == 0xA)
                                        value = settings->reg_settings[i].i2c_reg_val;
                                else {
                                        i2c_success =
                                                dal_ddc_service_query_ddc_data(
                                                pipe_ctx->stream->link->ddc,
                                                slave_address, &offset, 1, &value, 1);
                                        if (!i2c_success)
                                                goto i2c_write_fail;