/*
 * Copyright © 2014 Intel Corporation
 *
 * 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 (including the next
 * paragraph) 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 AUTHORS OR COPYRIGHT HOLDERS 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.
 */

/**
 * DOC: Panel Self Refresh (PSR/SRD)
 *
 * Since Haswell Display controller supports Panel Self-Refresh on display
 * panels witch have a remote frame buffer (RFB) implemented according to PSR
 * spec in eDP1.3. PSR feature allows the display to go to lower standby states
 * when system is idle but display is on as it eliminates display refresh
 * request to DDR memory completely as long as the frame buffer for that
 * display is unchanged.
 *
 * Panel Self Refresh must be supported by both Hardware (source) and
 * Panel (sink).
 *
 * PSR saves power by caching the framebuffer in the panel RFB, which allows us
 * to power down the link and memory controller. For DSI panels the same idea
 * is called "manual mode".
 *
 * The implementation uses the hardware-based PSR support which automatically
 * enters/exits self-refresh mode. The hardware takes care of sending the
 * required DP aux message and could even retrain the link (that part isn't
 * enabled yet though). The hardware also keeps track of any frontbuffer
 * changes to know when to exit self-refresh mode again. Unfortunately that
 * part doesn't work too well, hence why the i915 PSR support uses the
 * software frontbuffer tracking to make sure it doesn't miss a screen
 * update. For this integration intel_psr_invalidate() and intel_psr_flush()
 * get called by the frontbuffer tracking code. Note that because of locking
 * issues the self-refresh re-enable code is done from a work queue, which
 * must be correctly synchronized/cancelled when shutting down the pipe."
 */

#include <drm/drmP.h>

#include "intel_drv.h"
#include "i915_drv.h"

static bool is_edp_psr(struct intel_dp *intel_dp)
{
        return intel_dp->psr_dpcd[0] & DP_PSR_IS_SUPPORTED;
}

static bool vlv_is_psr_active_on_pipe(struct drm_device *dev, int pipe)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        uint32_t val;

        val = I915_READ(VLV_PSRSTAT(pipe)) &
              VLV_EDP_PSR_CURR_STATE_MASK;
        return (val == VLV_EDP_PSR_ACTIVE_NORFB_UP) ||
               (val == VLV_EDP_PSR_ACTIVE_SF_UPDATE);
}

static void intel_psr_write_vsc(struct intel_dp *intel_dp,
                                const struct edp_vsc_psr *vsc_psr)
{
        struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
        struct drm_device *dev = dig_port->base.base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct intel_crtc *crtc = to_intel_crtc(dig_port->base.base.crtc);
        enum transcoder cpu_transcoder = crtc->config->cpu_transcoder;
        i915_reg_t ctl_reg = HSW_TVIDEO_DIP_CTL(cpu_transcoder);
        uint32_t *data = (uint32_t *) vsc_psr;
        unsigned int i;

        /* As per BSPec (Pipe Video Data Island Packet), we need to disable
           the video DIP being updated before program video DIP data buffer
           registers for DIP being updated. */
        I915_WRITE(ctl_reg, 0);
        POSTING_READ(ctl_reg);

        for (i = 0; i < sizeof(*vsc_psr); i += 4) {
                I915_WRITE(HSW_TVIDEO_DIP_VSC_DATA(cpu_transcoder,
                                                   i >> 2), *data);
                data++;
        }
        for (; i < VIDEO_DIP_VSC_DATA_SIZE; i += 4)
                I915_WRITE(HSW_TVIDEO_DIP_VSC_DATA(cpu_transcoder,
                                                   i >> 2), 0);

        I915_WRITE(ctl_reg, VIDEO_DIP_ENABLE_VSC_HSW);
        POSTING_READ(ctl_reg);
}

static void vlv_psr_setup_vsc(struct intel_dp *intel_dp)
{
        struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
        struct drm_device *dev = intel_dig_port->base.base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct drm_crtc *crtc = intel_dig_port->base.base.crtc;
        enum pipe pipe = to_intel_crtc(crtc)->pipe;
        uint32_t val;

        /* VLV auto-generate VSC package as per EDP 1.3 spec, Table 3.10 */
        val  = I915_READ(VLV_VSCSDP(pipe));
        val &= ~VLV_EDP_PSR_SDP_FREQ_MASK;
        val |= VLV_EDP_PSR_SDP_FREQ_EVFRAME;
        I915_WRITE(VLV_VSCSDP(pipe), val);
}

static void skl_psr_setup_su_vsc(struct intel_dp *intel_dp)
{
        struct edp_vsc_psr psr_vsc;

        /* Prepare VSC Header for SU as per EDP 1.4 spec, Table 6.11 */
        memset(&psr_vsc, 0, sizeof(psr_vsc));
        psr_vsc.sdp_header.HB0 = 0;
        psr_vsc.sdp_header.HB1 = 0x7;
        psr_vsc.sdp_header.HB2 = 0x3;
        psr_vsc.sdp_header.HB3 = 0xb;
        intel_psr_write_vsc(intel_dp, &psr_vsc);
}

static void hsw_psr_setup_vsc(struct intel_dp *intel_dp)
{
        struct edp_vsc_psr psr_vsc;

        /* Prepare VSC packet as per EDP 1.3 spec, Table 3.10 */
        memset(&psr_vsc, 0, sizeof(psr_vsc));
        psr_vsc.sdp_header.HB0 = 0;
        psr_vsc.sdp_header.HB1 = 0x7;
        psr_vsc.sdp_header.HB2 = 0x2;
        psr_vsc.sdp_header.HB3 = 0x8;
        intel_psr_write_vsc(intel_dp, &psr_vsc);
}

static void vlv_psr_enable_sink(struct intel_dp *intel_dp)
{
        drm_dp_dpcd_writeb(&intel_dp->aux, DP_PSR_EN_CFG,
                           DP_PSR_ENABLE | DP_PSR_MAIN_LINK_ACTIVE);
}

static i915_reg_t psr_aux_ctl_reg(struct drm_i915_private *dev_priv,
                                       enum port port)
{
        if (INTEL_INFO(dev_priv)->gen >= 9)
                return DP_AUX_CH_CTL(port);
        else
                return EDP_PSR_AUX_CTL;
}

static i915_reg_t psr_aux_data_reg(struct drm_i915_private *dev_priv,
                                        enum port port, int index)
{
        if (INTEL_INFO(dev_priv)->gen >= 9)
                return DP_AUX_CH_DATA(port, index);
        else
                return EDP_PSR_AUX_DATA(index);
}

static void hsw_psr_enable_sink(struct intel_dp *intel_dp)
{
        struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
        struct drm_device *dev = dig_port->base.base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        uint32_t aux_clock_divider;
        i915_reg_t aux_ctl_reg;
        int precharge = 0x3;
        static const uint8_t aux_msg[] = {
                [0] = DP_AUX_NATIVE_WRITE << 4,
                [1] = DP_SET_POWER >> 8,
                [2] = DP_SET_POWER & 0xff,
                [3] = 1 - 1,
                [4] = DP_SET_POWER_D0,
        };
        enum port port = dig_port->port;
        int i;

        BUILD_BUG_ON(sizeof(aux_msg) > 20);

        aux_clock_divider = intel_dp->get_aux_clock_divider(intel_dp, 0);

        /* Enable AUX frame sync at sink */
        if (dev_priv->psr.aux_frame_sync)
                drm_dp_dpcd_writeb(&intel_dp->aux,
                                DP_SINK_DEVICE_AUX_FRAME_SYNC_CONF,
                                DP_AUX_FRAME_SYNC_ENABLE);

        aux_ctl_reg = psr_aux_ctl_reg(dev_priv, port);

        /* Setup AUX registers */
        for (i = 0; i < sizeof(aux_msg); i += 4)
                I915_WRITE(psr_aux_data_reg(dev_priv, port, i >> 2),
                           intel_dp_pack_aux(&aux_msg[i], sizeof(aux_msg) - i));

        if (INTEL_INFO(dev)->gen >= 9) {
                uint32_t val;

                val = I915_READ(aux_ctl_reg);
                val &= ~DP_AUX_CH_CTL_TIME_OUT_MASK;
                val |= DP_AUX_CH_CTL_TIME_OUT_1600us;
                val &= ~DP_AUX_CH_CTL_MESSAGE_SIZE_MASK;
                val |= (sizeof(aux_msg) << DP_AUX_CH_CTL_MESSAGE_SIZE_SHIFT);
                /* Use hardcoded data values for PSR, frame sync and GTC */
                val &= ~DP_AUX_CH_CTL_PSR_DATA_AUX_REG_SKL;
                val &= ~DP_AUX_CH_CTL_FS_DATA_AUX_REG_SKL;
                val &= ~DP_AUX_CH_CTL_GTC_DATA_AUX_REG_SKL;
                I915_WRITE(aux_ctl_reg, val);
        } else {
                I915_WRITE(aux_ctl_reg,
                   DP_AUX_CH_CTL_TIME_OUT_400us |
                   (sizeof(aux_msg) << DP_AUX_CH_CTL_MESSAGE_SIZE_SHIFT) |
                   (precharge << DP_AUX_CH_CTL_PRECHARGE_2US_SHIFT) |
                   (aux_clock_divider << DP_AUX_CH_CTL_BIT_CLOCK_2X_SHIFT));
        }

        if (dev_priv->psr.link_standby)
                drm_dp_dpcd_writeb(&intel_dp->aux, DP_PSR_EN_CFG,
                                   DP_PSR_ENABLE | DP_PSR_MAIN_LINK_ACTIVE);
        else
                drm_dp_dpcd_writeb(&intel_dp->aux, DP_PSR_EN_CFG,
                                   DP_PSR_ENABLE);
}

static void vlv_psr_enable_source(struct intel_dp *intel_dp)
{
        struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
        struct drm_device *dev = dig_port->base.base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct drm_crtc *crtc = dig_port->base.base.crtc;
        enum pipe pipe = to_intel_crtc(crtc)->pipe;

        /* Transition from PSR_state 0 to PSR_state 1, i.e. PSR Inactive */
        I915_WRITE(VLV_PSRCTL(pipe),
                   VLV_EDP_PSR_MODE_SW_TIMER |
                   VLV_EDP_PSR_SRC_TRANSMITTER_STATE |
                   VLV_EDP_PSR_ENABLE);
}

static void vlv_psr_activate(struct intel_dp *intel_dp)
{
        struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
        struct drm_device *dev = dig_port->base.base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct drm_crtc *crtc = dig_port->base.base.crtc;
        enum pipe pipe = to_intel_crtc(crtc)->pipe;

        /* Let's do the transition from PSR_state 1 to PSR_state 2
         * that is PSR transition to active - static frame transmission.
         * Then Hardware is responsible for the transition to PSR_state 3
         * that is PSR active - no Remote Frame Buffer (RFB) update.
         */
        I915_WRITE(VLV_PSRCTL(pipe), I915_READ(VLV_PSRCTL(pipe)) |
                   VLV_EDP_PSR_ACTIVE_ENTRY);
}

static void hsw_psr_enable_source(struct intel_dp *intel_dp)
{
        struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
        struct drm_device *dev = dig_port->base.base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;

        uint32_t max_sleep_time = 0x1f;
        /*
         * Let's respect VBT in case VBT asks a higher idle_frame value.
         * Let's use 6 as the minimum to cover all known cases including
         * the off-by-one issue that HW has in some cases. Also there are
         * cases where sink should be able to train
         * with the 5 or 6 idle patterns.
         */
        uint32_t idle_frames = max(6, dev_priv->vbt.psr.idle_frames);
        uint32_t val = 0x0;

        if (IS_HASWELL(dev))
                val |= EDP_PSR_MIN_LINK_ENTRY_TIME_8_LINES;

        if (dev_priv->psr.link_standby)
                val |= EDP_PSR_LINK_STANDBY;

        I915_WRITE(EDP_PSR_CTL, val |
                   max_sleep_time << EDP_PSR_MAX_SLEEP_TIME_SHIFT |
                   idle_frames << EDP_PSR_IDLE_FRAME_SHIFT |
                   EDP_PSR_ENABLE);

        if (dev_priv->psr.psr2_support)
                I915_WRITE(EDP_PSR2_CTL, EDP_PSR2_ENABLE |
                                EDP_SU_TRACK_ENABLE | EDP_PSR2_TP2_TIME_100);
}

static bool intel_psr_match_conditions(struct intel_dp *intel_dp)
{
        struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
        struct drm_device *dev = dig_port->base.base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct drm_crtc *crtc = dig_port->base.base.crtc;
        struct intel_crtc *intel_crtc = to_intel_crtc(crtc);

        lockdep_assert_held(&dev_priv->psr.lock);
        WARN_ON(!drm_modeset_is_locked(&dev->mode_config.connection_mutex));
        WARN_ON(!drm_modeset_is_locked(&crtc->mutex));

        dev_priv->psr.source_ok = false;

        /*
         * HSW spec explicitly says PSR is tied to port A.
         * BDW+ platforms with DDI implementation of PSR have different
         * PSR registers per transcoder and we only implement transcoder EDP
         * ones. Since by Display design transcoder EDP is tied to port A
         * we can safely escape based on the port A.
         */
        if (HAS_DDI(dev) && dig_port->port != PORT_A) {
                DRM_DEBUG_KMS("PSR condition failed: Port not supported\n");
                return false;
        }

        if (!i915.enable_psr) {
                DRM_DEBUG_KMS("PSR disable by flag\n");
                return false;
        }

        if ((IS_VALLEYVIEW(dev) || IS_CHERRYVIEW(dev)) &&
            !dev_priv->psr.link_standby) {
                DRM_ERROR("PSR condition failed: Link off requested but not supported on this platform\n");
                return false;
        }

        if (IS_HASWELL(dev) &&
            I915_READ(HSW_STEREO_3D_CTL(intel_crtc->config->cpu_transcoder)) &
                      S3D_ENABLE) {
                DRM_DEBUG_KMS("PSR condition failed: Stereo 3D is Enabled\n");
                return false;
        }

        if (IS_HASWELL(dev) &&
            intel_crtc->config->base.adjusted_mode.flags & DRM_MODE_FLAG_INTERLACE) {
                DRM_DEBUG_KMS("PSR condition failed: Interlaced is Enabled\n");
                return false;
        }

        dev_priv->psr.source_ok = true;
        return true;
}

static void intel_psr_activate(struct intel_dp *intel_dp)
{
        struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
        struct drm_device *dev = intel_dig_port->base.base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;

        WARN_ON(I915_READ(EDP_PSR_CTL) & EDP_PSR_ENABLE);
        WARN_ON(dev_priv->psr.active);
        lockdep_assert_held(&dev_priv->psr.lock);

        /* Enable/Re-enable PSR on the host */
        if (HAS_DDI(dev))
                /* On HSW+ after we enable PSR on source it will activate it
                 * as soon as it match configure idle_frame count. So
                 * we just actually enable it here on activation time.
                 */
                hsw_psr_enable_source(intel_dp);
        else
                vlv_psr_activate(intel_dp);

        dev_priv->psr.active = true;
}

/**
 * intel_psr_enable - Enable PSR
 * @intel_dp: Intel DP
 *
 * This function can only be called after the pipe is fully trained and enabled.
 */
void intel_psr_enable(struct intel_dp *intel_dp)
{
        struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
        struct drm_device *dev = intel_dig_port->base.base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct intel_crtc *crtc = to_intel_crtc(intel_dig_port->base.base.crtc);

        if (!HAS_PSR(dev)) {
                DRM_DEBUG_KMS("PSR not supported on this platform\n");
                return;
        }

        if (!is_edp_psr(intel_dp)) {
                DRM_DEBUG_KMS("PSR not supported by this panel\n");
                return;
        }

        mutex_lock(&dev_priv->psr.lock);
        if (dev_priv->psr.enabled) {
                DRM_DEBUG_KMS("PSR already in use\n");
                goto unlock;
        }

        if (!intel_psr_match_conditions(intel_dp))
                goto unlock;

        dev_priv->psr.busy_frontbuffer_bits = 0;

        if (HAS_DDI(dev)) {
                hsw_psr_setup_vsc(intel_dp);

                if (dev_priv->psr.psr2_support) {
                        /* PSR2 is restricted to work with panel resolutions upto 3200x2000 */
                        if (crtc->config->pipe_src_w > 3200 ||
                                crtc->config->pipe_src_h > 2000)
                                dev_priv->psr.psr2_support = false;
                        else
                                skl_psr_setup_su_vsc(intel_dp);
                }

                /*
                 * Per Spec: Avoid continuous PSR exit by masking MEMUP and HPD.
                 * Also mask LPSP to avoid dependency on other drivers that
                 * might block runtime_pm besides preventing other hw tracking
                 * issues now we can rely on frontbuffer tracking.
                 */
                I915_WRITE(EDP_PSR_DEBUG_CTL, EDP_PSR_DEBUG_MASK_MEMUP |
                           EDP_PSR_DEBUG_MASK_HPD | EDP_PSR_DEBUG_MASK_LPSP);

                /* Enable PSR on the panel */
                hsw_psr_enable_sink(intel_dp);

                if (INTEL_INFO(dev)->gen >= 9)
                        intel_psr_activate(intel_dp);
        } else {
                vlv_psr_setup_vsc(intel_dp);

                /* Enable PSR on the panel */
                vlv_psr_enable_sink(intel_dp);

                /* On HSW+ enable_source also means go to PSR entry/active
                 * state as soon as idle_frame achieved and here would be
                 * to soon. However on VLV enable_source just enable PSR
                 * but let it on inactive state. So we might do this prior
                 * to active transition, i.e. here.
                 */
                vlv_psr_enable_source(intel_dp);
        }

        /*
         * FIXME: Activation should happen immediately since this function
         * is just called after pipe is fully trained and enabled.
         * However on every platform we face issues when first activation
         * follows a modeset so quickly.
         *     - On VLV/CHV we get bank screen on first activation
         *     - On HSW/BDW we get a recoverable frozen screen until next
         *       exit-activate sequence.
         */
        if (INTEL_INFO(dev)->gen < 9)
                schedule_delayed_work(&dev_priv->psr.work,
                                      msecs_to_jiffies(intel_dp->panel_power_cycle_delay * 5));

        dev_priv->psr.enabled = intel_dp;
unlock:
        mutex_unlock(&dev_priv->psr.lock);
}

static void vlv_psr_disable(struct intel_dp *intel_dp)
{
        struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
        struct drm_device *dev = intel_dig_port->base.base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct intel_crtc *intel_crtc =
                to_intel_crtc(intel_dig_port->base.base.crtc);
        uint32_t val;

        if (dev_priv->psr.active) {
                /* Put VLV PSR back to PSR_state 0 that is PSR Disabled. */
                if (wait_for((I915_READ(VLV_PSRSTAT(intel_crtc->pipe)) &
                              VLV_EDP_PSR_IN_TRANS) == 0, 1))
                        WARN(1, "PSR transition took longer than expected\n");

                val = I915_READ(VLV_PSRCTL(intel_crtc->pipe));
                val &= ~VLV_EDP_PSR_ACTIVE_ENTRY;
                val &= ~VLV_EDP_PSR_ENABLE;
                val &= ~VLV_EDP_PSR_MODE_MASK;
                I915_WRITE(VLV_PSRCTL(intel_crtc->pipe), val);

                dev_priv->psr.active = false;
        } else {
                WARN_ON(vlv_is_psr_active_on_pipe(dev, intel_crtc->pipe));
        }
}

static void hsw_psr_disable(struct intel_dp *intel_dp)
{
        struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
        struct drm_device *dev = intel_dig_port->base.base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;

        if (dev_priv->psr.active) {
                I915_WRITE(EDP_PSR_CTL,
                           I915_READ(EDP_PSR_CTL) & ~EDP_PSR_ENABLE);

                /* Wait till PSR is idle */
                if (_wait_for((I915_READ(EDP_PSR_STATUS_CTL) &
                               EDP_PSR_STATUS_STATE_MASK) == 0, 2000, 10))
                        DRM_ERROR("Timed out waiting for PSR Idle State\n");

                dev_priv->psr.active = false;
        } else {
                WARN_ON(I915_READ(EDP_PSR_CTL) & EDP_PSR_ENABLE);
        }
}

/**
 * intel_psr_disable - Disable PSR
 * @intel_dp: Intel DP
 *
 * This function needs to be called before disabling pipe.
 */
void intel_psr_disable(struct intel_dp *intel_dp)
{
        struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
        struct drm_device *dev = intel_dig_port->base.base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;

        mutex_lock(&dev_priv->psr.lock);
        if (!dev_priv->psr.enabled) {
                mutex_unlock(&dev_priv->psr.lock);
                return;
        }

        /* Disable PSR on Source */
        if (HAS_DDI(dev))
                hsw_psr_disable(intel_dp);
        else
                vlv_psr_disable(intel_dp);

        /* Disable PSR on Sink */
        drm_dp_dpcd_writeb(&intel_dp->aux, DP_PSR_EN_CFG, 0);

        dev_priv->psr.enabled = NULL;
        mutex_unlock(&dev_priv->psr.lock);

        cancel_delayed_work_sync(&dev_priv->psr.work);
}

static void intel_psr_work(struct work_struct *work)
{
        struct drm_i915_private *dev_priv =
                container_of(work, typeof(*dev_priv), psr.work.work);
        struct intel_dp *intel_dp = dev_priv->psr.enabled;
        struct drm_crtc *crtc = dp_to_dig_port(intel_dp)->base.base.crtc;
        enum pipe pipe = to_intel_crtc(crtc)->pipe;

        /* We have to make sure PSR is ready for re-enable
         * otherwise it keeps disabled until next full enable/disable cycle.
         * PSR might take some time to get fully disabled
         * and be ready for re-enable.
         */
        if (HAS_DDI(dev_priv->dev)) {
                if (wait_for((I915_READ(EDP_PSR_STATUS_CTL) &
                              EDP_PSR_STATUS_STATE_MASK) == 0, 50)) {
                        DRM_ERROR("Timed out waiting for PSR Idle for re-enable\n");
                        return;
                }
        } else {
                if (wait_for((I915_READ(VLV_PSRSTAT(pipe)) &
                              VLV_EDP_PSR_IN_TRANS) == 0, 1)) {
                        DRM_ERROR("Timed out waiting for PSR Idle for re-enable\n");
                        return;
                }
        }
        mutex_lock(&dev_priv->psr.lock);
        intel_dp = dev_priv->psr.enabled;

        if (!intel_dp)
                goto unlock;

        /*
         * The delayed work can race with an invalidate hence we need to
         * recheck. Since psr_flush first clears this and then reschedules we
         * won't ever miss a flush when bailing out here.
         */
        if (dev_priv->psr.busy_frontbuffer_bits)
                goto unlock;

        intel_psr_activate(intel_dp);
unlock:
        mutex_unlock(&dev_priv->psr.lock);
}

static void intel_psr_exit(struct drm_device *dev)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct intel_dp *intel_dp = dev_priv->psr.enabled;
        struct drm_crtc *crtc = dp_to_dig_port(intel_dp)->base.base.crtc;
        enum pipe pipe = to_intel_crtc(crtc)->pipe;
        u32 val;

        if (!dev_priv->psr.active)
                return;

        if (HAS_DDI(dev)) {
                val = I915_READ(EDP_PSR_CTL);

                WARN_ON(!(val & EDP_PSR_ENABLE));

                I915_WRITE(EDP_PSR_CTL, val & ~EDP_PSR_ENABLE);
        } else {
                val = I915_READ(VLV_PSRCTL(pipe));

                /* Here we do the transition from PSR_state 3 to PSR_state 5
                 * directly once PSR State 4 that is active with single frame
                 * update can be skipped. PSR_state 5 that is PSR exit then
                 * Hardware is responsible to transition back to PSR_state 1
                 * that is PSR inactive. Same state after
                 * vlv_edp_psr_enable_source.
                 */
                val &= ~VLV_EDP_PSR_ACTIVE_ENTRY;
                I915_WRITE(VLV_PSRCTL(pipe), val);

                /* Send AUX wake up - Spec says after transitioning to PSR
                 * active we have to send AUX wake up by writing 01h in DPCD
                 * 600h of sink device.
                 * XXX: This might slow down the transition, but without this
                 * HW doesn't complete the transition to PSR_state 1 and we
                 * never get the screen updated.
                 */
                drm_dp_dpcd_writeb(&intel_dp->aux, DP_SET_POWER,
                                   DP_SET_POWER_D0);
        }

        dev_priv->psr.active = false;
}

/**
 * intel_psr_single_frame_update - Single Frame Update
 * @dev: DRM device
 * @frontbuffer_bits: frontbuffer plane tracking bits
 *
 * Some platforms support a single frame update feature that is used to
 * send and update only one frame on Remote Frame Buffer.
 * So far it is only implemented for Valleyview and Cherryview because
 * hardware requires this to be done before a page flip.
 */
void intel_psr_single_frame_update(struct drm_device *dev,
                                   unsigned frontbuffer_bits)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct drm_crtc *crtc;
        enum pipe pipe;
        u32 val;

        /*
         * Single frame update is already supported on BDW+ but it requires
         * many W/A and it isn't really needed.
         */
        if (!IS_VALLEYVIEW(dev) && !IS_CHERRYVIEW(dev))
                return;

        mutex_lock(&dev_priv->psr.lock);
        if (!dev_priv->psr.enabled) {
                mutex_unlock(&dev_priv->psr.lock);
                return;
        }

        crtc = dp_to_dig_port(dev_priv->psr.enabled)->base.base.crtc;
        pipe = to_intel_crtc(crtc)->pipe;

        if (frontbuffer_bits & INTEL_FRONTBUFFER_ALL_MASK(pipe)) {
                val = I915_READ(VLV_PSRCTL(pipe));

                /*
                 * We need to set this bit before writing registers for a flip.
                 * This bit will be self-clear when it gets to the PSR active state.
                 */
                I915_WRITE(VLV_PSRCTL(pipe), val | VLV_EDP_PSR_SINGLE_FRAME_UPDATE);
        }
        mutex_unlock(&dev_priv->psr.lock);
}

/**
 * intel_psr_invalidate - Invalidade PSR
 * @dev: DRM device
 * @frontbuffer_bits: frontbuffer plane tracking bits
 *
 * Since the hardware frontbuffer tracking has gaps we need to integrate
 * with the software frontbuffer tracking. This function gets called every
 * time frontbuffer rendering starts and a buffer gets dirtied. PSR must be
 * disabled if the frontbuffer mask contains a buffer relevant to PSR.
 *
 * Dirty frontbuffers relevant to PSR are tracked in busy_frontbuffer_bits."
 */
void intel_psr_invalidate(struct drm_device *dev,
                          unsigned frontbuffer_bits)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct drm_crtc *crtc;
        enum pipe pipe;

        mutex_lock(&dev_priv->psr.lock);
        if (!dev_priv->psr.enabled) {
                mutex_unlock(&dev_priv->psr.lock);
                return;
        }

        crtc = dp_to_dig_port(dev_priv->psr.enabled)->base.base.crtc;
        pipe = to_intel_crtc(crtc)->pipe;

        frontbuffer_bits &= INTEL_FRONTBUFFER_ALL_MASK(pipe);
        dev_priv->psr.busy_frontbuffer_bits |= frontbuffer_bits;

        if (frontbuffer_bits)
                intel_psr_exit(dev);

        mutex_unlock(&dev_priv->psr.lock);
}

/**
 * intel_psr_flush - Flush PSR
 * @dev: DRM device
 * @frontbuffer_bits: frontbuffer plane tracking bits
 * @origin: which operation caused the flush
 *
 * Since the hardware frontbuffer tracking has gaps we need to integrate
 * with the software frontbuffer tracking. This function gets called every
 * time frontbuffer rendering has completed and flushed out to memory. PSR
 * can be enabled again if no other frontbuffer relevant to PSR is dirty.
 *
 * Dirty frontbuffers relevant to PSR are tracked in busy_frontbuffer_bits.
 */
void intel_psr_flush(struct drm_device *dev,
                     unsigned frontbuffer_bits, enum fb_op_origin origin)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct drm_crtc *crtc;
        enum pipe pipe;

        mutex_lock(&dev_priv->psr.lock);
        if (!dev_priv->psr.enabled) {
                mutex_unlock(&dev_priv->psr.lock);
                return;
        }

        crtc = dp_to_dig_port(dev_priv->psr.enabled)->base.base.crtc;
        pipe = to_intel_crtc(crtc)->pipe;

        frontbuffer_bits &= INTEL_FRONTBUFFER_ALL_MASK(pipe);
        dev_priv->psr.busy_frontbuffer_bits &= ~frontbuffer_bits;

        /* By definition flush = invalidate + flush */
        if (frontbuffer_bits)
                intel_psr_exit(dev);

        if (!dev_priv->psr.active && !dev_priv->psr.busy_frontbuffer_bits)
                if (!work_busy(&dev_priv->psr.work.work))
                        schedule_delayed_work(&dev_priv->psr.work,
                                              msecs_to_jiffies(100));
        mutex_unlock(&dev_priv->psr.lock);
}

/**
 * intel_psr_init - Init basic PSR work and mutex.
 * @dev: DRM device
 *
 * This function is  called only once at driver load to initialize basic
 * PSR stuff.
 */
void intel_psr_init(struct drm_device *dev)
{
        struct drm_i915_private *dev_priv = dev->dev_private;

        dev_priv->psr_mmio_base = IS_HASWELL(dev_priv) ?
                HSW_EDP_PSR_BASE : BDW_EDP_PSR_BASE;

        /* Per platform default */
        if (i915.enable_psr == -1) {
                if (IS_HASWELL(dev) || IS_BROADWELL(dev) ||
                    IS_VALLEYVIEW(dev) || IS_CHERRYVIEW(dev))
                        i915.enable_psr = 1;
                else
                        i915.enable_psr = 0;
        }

        /* Set link_standby x link_off defaults */
        if (IS_HASWELL(dev) || IS_BROADWELL(dev))
                /* HSW and BDW require workarounds that we don't implement. */
                dev_priv->psr.link_standby = false;
        else if (IS_VALLEYVIEW(dev) || IS_CHERRYVIEW(dev))
                /* On VLV and CHV only standby mode is supported. */
                dev_priv->psr.link_standby = true;
        else
                /* For new platforms let's respect VBT back again */
                dev_priv->psr.link_standby = dev_priv->vbt.psr.full_link;

        /* Override link_standby x link_off defaults */
        if (i915.enable_psr == 2 && !dev_priv->psr.link_standby) {
                DRM_DEBUG_KMS("PSR: Forcing link standby\n");
                dev_priv->psr.link_standby = true;
        }
        if (i915.enable_psr == 3 && dev_priv->psr.link_standby) {
                DRM_DEBUG_KMS("PSR: Forcing main link off\n");
                dev_priv->psr.link_standby = false;
        }

        INIT_DELAYED_WORK(&dev_priv->psr.work, intel_psr_work);
        mutex_init(&dev_priv->psr.lock);
}