/*
 * Copyright 2009 Red Hat 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: Ben Skeggs
 */

#include <drm/display/drm_dp_helper.h>

#include "nouveau_drv.h"
#include "nouveau_connector.h"
#include "nouveau_encoder.h"
#include "nouveau_crtc.h"

#include <nvif/if0011.h>

MODULE_PARM_DESC(mst, "Enable DisplayPort multi-stream (default: enabled)");
static int nouveau_mst = 1;
module_param_named(mst, nouveau_mst, int, 0400);

static bool
nouveau_dp_has_sink_count(struct drm_connector *connector,
                          struct nouveau_encoder *outp)
{
        return drm_dp_read_sink_count_cap(connector, outp->dp.dpcd, &outp->dp.desc);
}

static bool
nouveau_dp_probe_lttpr(struct nouveau_encoder *outp)
{
        u8 rev, size = sizeof(rev);
        int ret;

        ret = nvif_outp_dp_aux_xfer(&outp->outp, DP_AUX_NATIVE_READ, &size,
                                    DP_LT_TUNABLE_PHY_REPEATER_FIELD_DATA_STRUCTURE_REV,
                                    &rev);
        if (ret || size < sizeof(rev) || rev < 0x14)
                return false;

        return true;
}

static enum drm_connector_status
nouveau_dp_probe_dpcd(struct nouveau_connector *nv_connector,
                      struct nouveau_encoder *outp)
{
        struct drm_connector *connector = &nv_connector->base;
        struct drm_dp_aux *aux = &nv_connector->aux;
        struct nv50_mstm *mstm = NULL;
        enum drm_connector_status status = connector_status_disconnected;
        int ret;
        u8 *dpcd = outp->dp.dpcd;

        outp->dp.lttpr.nr = 0;
        outp->dp.rate_nr  = 0;
        outp->dp.link_nr  = 0;
        outp->dp.link_bw  = 0;

        if (connector->connector_type != DRM_MODE_CONNECTOR_eDP &&
            nouveau_dp_probe_lttpr(outp) &&
            !drm_dp_read_dpcd_caps(aux, dpcd) &&
            !drm_dp_read_lttpr_common_caps(aux, dpcd, outp->dp.lttpr.caps)) {
                int nr = drm_dp_lttpr_count(outp->dp.lttpr.caps);

                if (!drm_dp_lttpr_init(aux, nr))
                        outp->dp.lttpr.nr = nr;
        }

        ret = drm_dp_read_dpcd_caps(aux, dpcd);
        if (ret < 0)
                goto out;

        outp->dp.link_nr = dpcd[DP_MAX_LANE_COUNT] & DP_MAX_LANE_COUNT_MASK;
        if (outp->dcb->dpconf.link_nr < outp->dp.link_nr)
                outp->dp.link_nr = outp->dcb->dpconf.link_nr;

        if (outp->dp.lttpr.nr) {
                int links = drm_dp_lttpr_max_lane_count(outp->dp.lttpr.caps);

                if (links && links < outp->dp.link_nr)
                        outp->dp.link_nr = links;
        }

        if (connector->connector_type == DRM_MODE_CONNECTOR_eDP && dpcd[DP_DPCD_REV] >= 0x13) {
                __le16 rates[DP_MAX_SUPPORTED_RATES];

                ret = drm_dp_dpcd_read(aux, DP_SUPPORTED_LINK_RATES, rates, sizeof(rates));
                if (ret == sizeof(rates)) {
                        for (int i = 0; i < ARRAY_SIZE(rates); i++) {
                                u32 rate = (le16_to_cpu(rates[i]) * 200) / 10;
                                int j;

                                if (!rate)
                                        break;

                                for (j = 0; j < outp->dp.rate_nr; j++) {
                                        if (rate > outp->dp.rate[j].rate) {
                                                for (int k = outp->dp.rate_nr; k > j; k--)
                                                        outp->dp.rate[k] = outp->dp.rate[k - 1];
                                                break;
                                        }
                                }

                                outp->dp.rate[j].dpcd = i;
                                outp->dp.rate[j].rate = rate;
                                outp->dp.rate_nr++;
                        }
                }
        }

        if (!outp->dp.rate_nr) {
                const u32 rates[] = { 810000, 540000, 270000, 162000 };
                u32 max_rate = dpcd[DP_MAX_LINK_RATE] * 27000;

                if (outp->dp.lttpr.nr) {
                        int rate = drm_dp_lttpr_max_link_rate(outp->dp.lttpr.caps);

                        if (rate && rate < max_rate)
                                max_rate = rate;
                }

                max_rate = min_t(int, max_rate, outp->dcb->dpconf.link_bw);

                for (int i = 0; i < ARRAY_SIZE(rates); i++) {
                        if (rates[i] <= max_rate) {
                                outp->dp.rate[outp->dp.rate_nr].dpcd = -1;
                                outp->dp.rate[outp->dp.rate_nr].rate = rates[i];
                                outp->dp.rate_nr++;
                        }
                }

                if (WARN_ON(!outp->dp.rate_nr))
                        goto out;
        }

        ret = nvif_outp_dp_rates(&outp->outp, outp->dp.rate, outp->dp.rate_nr);
        if (ret)
                goto out;

        for (int i = 0; i < outp->dp.rate_nr; i++) {
                u32 link_bw = outp->dp.rate[i].rate;

                if (link_bw > outp->dp.link_bw)
                        outp->dp.link_bw = link_bw;
        }

        ret = drm_dp_read_desc(aux, &outp->dp.desc, drm_dp_is_branch(dpcd));
        if (ret < 0)
                goto out;

        if (nouveau_mst) {
                mstm = outp->dp.mstm;
                if (mstm)
                        mstm->can_mst = drm_dp_read_mst_cap(aux, dpcd) == DRM_DP_MST;
        }

        if (nouveau_dp_has_sink_count(connector, outp)) {
                ret = drm_dp_read_sink_count(aux);
                if (ret < 0)
                        goto out;

                outp->dp.sink_count = ret;

                /*
                 * Dongle connected, but no display. Don't bother reading
                 * downstream port info
                 */
                if (!outp->dp.sink_count)
                        return connector_status_disconnected;
        }

        ret = drm_dp_read_downstream_info(aux, dpcd,
                                          outp->dp.downstream_ports);
        if (ret < 0)
                goto out;

        status = connector_status_connected;
out:
        if (status != connector_status_connected) {
                /* Clear any cached info */
                outp->dp.sink_count = 0;
        }
        return status;
}

int
nouveau_dp_detect(struct nouveau_connector *nv_connector,
                  struct nouveau_encoder *nv_encoder)
{
        struct drm_device *dev = nv_encoder->base.base.dev;
        struct nouveau_drm *drm = nouveau_drm(dev);
        struct drm_connector *connector = &nv_connector->base;
        struct nv50_mstm *mstm = nv_encoder->dp.mstm;
        enum drm_connector_status status;
        u8 *dpcd = nv_encoder->dp.dpcd;
        int ret = NOUVEAU_DP_NONE, hpd;

        /* eDP ports don't support hotplugging - so there's no point in probing eDP ports unless we
         * haven't probed them once before.
         */
        if (connector->connector_type == DRM_MODE_CONNECTOR_eDP) {
                if (connector->status == connector_status_connected)
                        return NOUVEAU_DP_SST;
                else if (connector->status == connector_status_disconnected)
                        return NOUVEAU_DP_NONE;
        }

        // Ensure that the aux bus is enabled for probing
        drm_dp_dpcd_set_powered(&nv_connector->aux, true);

        mutex_lock(&nv_encoder->dp.hpd_irq_lock);
        if (mstm) {
                /* If we're not ready to handle MST state changes yet, just
                 * report the last status of the connector. We'll reprobe it
                 * once we've resumed.
                 */
                if (mstm->suspended) {
                        if (mstm->is_mst)
                                ret = NOUVEAU_DP_MST;
                        else if (connector->status ==
                                 connector_status_connected)
                                ret = NOUVEAU_DP_SST;

                        goto out;
                }
        }

        hpd = nvif_outp_detect(&nv_encoder->outp);
        if (hpd == NOT_PRESENT) {
                nvif_outp_dp_aux_pwr(&nv_encoder->outp, false);
                goto out;
        }
        nvif_outp_dp_aux_pwr(&nv_encoder->outp, true);

        status = nouveau_dp_probe_dpcd(nv_connector, nv_encoder);
        if (status == connector_status_disconnected) {
                nvif_outp_dp_aux_pwr(&nv_encoder->outp, false);
                goto out;
        }

        /* If we're in MST mode, we're done here */
        if (mstm && mstm->can_mst && mstm->is_mst) {
                ret = NOUVEAU_DP_MST;
                goto out;
        }

        NV_DEBUG(drm, "sink dpcd version: 0x%02x\n", dpcd[DP_DPCD_REV]);
        for (int i = 0; i < nv_encoder->dp.rate_nr; i++)
                NV_DEBUG(drm, "sink rate %d: %d\n", i, nv_encoder->dp.rate[i].rate);

        NV_DEBUG(drm, "encoder: %dx%d\n", nv_encoder->dcb->dpconf.link_nr,
                                          nv_encoder->dcb->dpconf.link_bw);
        NV_DEBUG(drm, "maximum: %dx%d\n", nv_encoder->dp.link_nr,
                                          nv_encoder->dp.link_bw);

        if (mstm && mstm->can_mst) {
                ret = nv50_mstm_detect(nv_encoder);
                if (ret == 1) {
                        ret = NOUVEAU_DP_MST;
                        goto out;
                } else if (ret != 0) {
                        nvif_outp_dp_aux_pwr(&nv_encoder->outp, false);
                        goto out;
                }
        }
        ret = NOUVEAU_DP_SST;

out:
        if (mstm && !mstm->suspended && ret != NOUVEAU_DP_MST)
                nv50_mstm_remove(mstm);

        /* GSP doesn't like when we try to do aux transactions on a port it considers disconnected,
         * and since we don't really have a usecase for that anyway - just disable the aux bus here
         * if we've decided the connector is disconnected
         */
        if (ret == NOUVEAU_DP_NONE)
                drm_dp_dpcd_set_powered(&nv_connector->aux, false);

        mutex_unlock(&nv_encoder->dp.hpd_irq_lock);
        return ret;
}

void
nouveau_dp_power_down(struct nouveau_encoder *outp)
{
        struct drm_dp_aux *aux = &outp->conn->aux;
        int ret;
        u8 pwr;

        mutex_lock(&outp->dp.hpd_irq_lock);

        ret = drm_dp_dpcd_readb(aux, DP_SET_POWER, &pwr);
        if (ret == 1) {
                pwr &= ~DP_SET_POWER_MASK;
                pwr |=  DP_SET_POWER_D3;
                drm_dp_dpcd_writeb(aux, DP_SET_POWER, pwr);
        }

        outp->dp.lt.nr = 0;
        mutex_unlock(&outp->dp.hpd_irq_lock);
}

static bool
nouveau_dp_train_link(struct nouveau_encoder *outp, bool retrain)
{
        struct drm_dp_aux *aux = &outp->conn->aux;
        bool post_lt = false;
        int ret, retries = 0;

        if ( (outp->dp.dpcd[DP_MAX_LANE_COUNT] & 0x20) &&
            !(outp->dp.dpcd[DP_MAX_DOWNSPREAD] & DP_TPS4_SUPPORTED))
            post_lt = true;

retry:
        ret = nvif_outp_dp_train(&outp->outp, outp->dp.dpcd,
                                              outp->dp.lttpr.nr,
                                              outp->dp.lt.nr,
                                              outp->dp.lt.bw,
                                              outp->dp.lt.mst,
                                              post_lt,
                                              retrain);
        if (ret)
                return false;

        if (post_lt) {
                u8 stat[DP_LINK_STATUS_SIZE];
                u8 prev[2];
                u8 time = 0, adjusts = 0, tmp;

                ret = drm_dp_dpcd_read_phy_link_status(aux, DP_PHY_DPRX, stat);
                if (ret)
                        return false;

                for (;;) {
                        if (!drm_dp_channel_eq_ok(stat, outp->dp.lt.nr)) {
                                ret = 1;
                                break;
                        }

                        if (!(stat[2] & 0x02))
                                break;

                        msleep(5);
                        time += 5;

                        memcpy(prev, &stat[4], sizeof(prev));
                        ret = drm_dp_dpcd_read_phy_link_status(aux, DP_PHY_DPRX, stat);
                        if (ret)
                                break;

                        if (!memcmp(prev, &stat[4], sizeof(prev))) {
                                if (time > 200)
                                        break;
                        } else {
                                u8 pe[4], vs[4];

                                if (adjusts++ == 6)
                                        break;

                                for (int i = 0; i < outp->dp.lt.nr; i++) {
                                        pe[i] = drm_dp_get_adjust_request_pre_emphasis(stat, i) >>
                                                        DP_TRAIN_PRE_EMPHASIS_SHIFT;
                                        vs[i] = drm_dp_get_adjust_request_voltage(stat, i) >>
                                                        DP_TRAIN_VOLTAGE_SWING_SHIFT;
                                }

                                ret = nvif_outp_dp_drive(&outp->outp, outp->dp.lt.nr, pe, vs);
                                if (ret)
                                        break;

                                time = 0;
                        }
                }

                if (drm_dp_dpcd_readb(aux, DP_LANE_COUNT_SET, &tmp) == 1) {
                        tmp &= ~0x20;
                        drm_dp_dpcd_writeb(aux, DP_LANE_COUNT_SET, tmp);
                }
        }

        if (ret == 1 && retries++ < 3)
                goto retry;

        return ret == 0;
}

bool
nouveau_dp_train(struct nouveau_encoder *outp, bool mst, u32 khz, u8 bpc)
{
        struct nouveau_drm *drm = nouveau_drm(outp->base.base.dev);
        struct drm_dp_aux *aux = &outp->conn->aux;
        u32 min_rate;
        u8 pwr;
        bool ret = true;

        if (mst)
                min_rate = outp->dp.link_nr * outp->dp.rate[0].rate;
        else
                min_rate = DIV_ROUND_UP(khz * bpc * 3, 8);

        NV_DEBUG(drm, "%s link training (mst:%d min_rate:%d)\n",
                 outp->base.base.name, mst, min_rate);

        mutex_lock(&outp->dp.hpd_irq_lock);

        if (drm_dp_dpcd_readb(aux, DP_SET_POWER, &pwr) == 1) {
                if ((pwr & DP_SET_POWER_MASK) != DP_SET_POWER_D0) {
                        pwr &= ~DP_SET_POWER_MASK;
                        pwr |=  DP_SET_POWER_D0;
                        drm_dp_dpcd_writeb(aux, DP_SET_POWER, pwr);
                }
        }

        for (int nr = outp->dp.link_nr; nr; nr >>= 1) {
                for (int rate = 0; rate < outp->dp.rate_nr; rate++) {
                        if (outp->dp.rate[rate].rate * nr >= min_rate) {
                                outp->dp.lt.nr = nr;
                                outp->dp.lt.bw = outp->dp.rate[rate].rate;
                                outp->dp.lt.mst = mst;
                                if (nouveau_dp_train_link(outp, false))
                                        goto done;
                        }
                }
        }

        ret = false;
done:
        mutex_unlock(&outp->dp.hpd_irq_lock);
        return ret;
}

static bool
nouveau_dp_link_check_locked(struct nouveau_encoder *outp)
{
        u8 link_status[DP_LINK_STATUS_SIZE];

        if (!outp || !outp->dp.lt.nr)
                return true;

        if (drm_dp_dpcd_read_phy_link_status(&outp->conn->aux, DP_PHY_DPRX, link_status) < 0)
                return false;

        if (drm_dp_channel_eq_ok(link_status, outp->dp.lt.nr))
                return true;

        return nouveau_dp_train_link(outp, true);
}

bool
nouveau_dp_link_check(struct nouveau_connector *nv_connector)
{
        struct nouveau_encoder *outp = nv_connector->dp_encoder;
        bool link_ok = true;

        if (outp) {
                mutex_lock(&outp->dp.hpd_irq_lock);
                if (outp->dp.lt.nr)
                        link_ok = nouveau_dp_link_check_locked(outp);
                mutex_unlock(&outp->dp.hpd_irq_lock);
        }

        return link_ok;
}

void
nouveau_dp_irq(struct work_struct *work)
{
        struct nouveau_connector *nv_connector =
                container_of(work, typeof(*nv_connector), irq_work);
        struct drm_connector *connector = &nv_connector->base;
        struct nouveau_encoder *outp = find_encoder(connector, DCB_OUTPUT_DP);
        struct nouveau_drm *drm = nouveau_drm(outp->base.base.dev);
        struct nv50_mstm *mstm;
        u64 hpd = 0;
        int ret;

        if (!outp)
                return;

        mstm = outp->dp.mstm;
        NV_DEBUG(drm, "service %s\n", connector->name);

        mutex_lock(&outp->dp.hpd_irq_lock);

        if (mstm && mstm->is_mst) {
                if (!nv50_mstm_service(drm, nv_connector, mstm))
                        hpd |= NVIF_CONN_EVENT_V0_UNPLUG;
        } else {
                drm_dp_cec_irq(&nv_connector->aux);

                if (nouveau_dp_has_sink_count(connector, outp)) {
                        ret = drm_dp_read_sink_count(&nv_connector->aux);
                        if (ret != outp->dp.sink_count)
                                hpd |= NVIF_CONN_EVENT_V0_PLUG;
                        if (ret >= 0)
                                outp->dp.sink_count = ret;
                }
        }

        mutex_unlock(&outp->dp.hpd_irq_lock);

        nouveau_connector_hpd(nv_connector, NVIF_CONN_EVENT_V0_IRQ | hpd);
}

/* TODO:
 * - Validate against the DP caps advertised by the GPU (we don't check these
 *   yet)
 */
enum drm_mode_status
nv50_dp_mode_valid(struct nouveau_encoder *outp,
                   const struct drm_display_mode *mode,
                   unsigned *out_clock)
{
        const unsigned int min_clock = 25000;
        unsigned int max_rate, mode_rate, ds_max_dotclock, clock = mode->clock;
        /* Check with the minmum bpc always, so we can advertise better modes.
         * In particlar not doing this causes modes to be dropped on HDR
         * displays as we might check with a bpc of 16 even.
         */
        const u8 bpp = 6 * 3;

        if (mode->flags & DRM_MODE_FLAG_INTERLACE && !outp->caps.dp_interlace)
                return MODE_NO_INTERLACE;

        if ((mode->flags & DRM_MODE_FLAG_3D_MASK) == DRM_MODE_FLAG_3D_FRAME_PACKING)
                clock *= 2;

        max_rate = outp->dp.link_nr * outp->dp.link_bw;
        mode_rate = DIV_ROUND_UP(clock * bpp, 8);
        if (mode_rate > max_rate)
                return MODE_CLOCK_HIGH;

        ds_max_dotclock = drm_dp_downstream_max_dotclock(outp->dp.dpcd, outp->dp.downstream_ports);
        if (ds_max_dotclock && clock > ds_max_dotclock)
                return MODE_CLOCK_HIGH;

        if (clock < min_clock)
                return MODE_CLOCK_LOW;

        if (out_clock)
                *out_clock = clock;

        return MODE_OK;
}