/* i915_irq.c -- IRQ support for the I915 -*- linux-c -*-
 */
/*
 * Copyright 2003 Tungsten Graphics, Inc., Cedar Park, Texas.
 * All Rights Reserved.
 *
 * 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, sub license, 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 NON-INFRINGEMENT.
 * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS 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.
 *
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/sysrq.h>
#include <linux/slab.h>
#include <drm/drmP.h>
#include <drm/i915_drm.h>
#include "i915_drv.h"
#include "i915_trace.h"
#include "intel_drv.h"

static const u32 hpd_ibx[] = {
        [HPD_CRT] = SDE_CRT_HOTPLUG,
        [HPD_SDVO_B] = SDE_SDVOB_HOTPLUG,
        [HPD_PORT_B] = SDE_PORTB_HOTPLUG,
        [HPD_PORT_C] = SDE_PORTC_HOTPLUG,
        [HPD_PORT_D] = SDE_PORTD_HOTPLUG
};

static const u32 hpd_cpt[] = {
        [HPD_CRT] = SDE_CRT_HOTPLUG_CPT,
        [HPD_SDVO_B] = SDE_SDVOB_HOTPLUG_CPT,
        [HPD_PORT_B] = SDE_PORTB_HOTPLUG_CPT,
        [HPD_PORT_C] = SDE_PORTC_HOTPLUG_CPT,
        [HPD_PORT_D] = SDE_PORTD_HOTPLUG_CPT
};

static const u32 hpd_mask_i915[] = {
        [HPD_CRT] = CRT_HOTPLUG_INT_EN,
        [HPD_SDVO_B] = SDVOB_HOTPLUG_INT_EN,
        [HPD_SDVO_C] = SDVOC_HOTPLUG_INT_EN,
        [HPD_PORT_B] = PORTB_HOTPLUG_INT_EN,
        [HPD_PORT_C] = PORTC_HOTPLUG_INT_EN,
        [HPD_PORT_D] = PORTD_HOTPLUG_INT_EN
};

static const u32 hpd_status_gen4[] = {
        [HPD_CRT] = CRT_HOTPLUG_INT_STATUS,
        [HPD_SDVO_B] = SDVOB_HOTPLUG_INT_STATUS_G4X,
        [HPD_SDVO_C] = SDVOC_HOTPLUG_INT_STATUS_G4X,
        [HPD_PORT_B] = PORTB_HOTPLUG_INT_STATUS,
        [HPD_PORT_C] = PORTC_HOTPLUG_INT_STATUS,
        [HPD_PORT_D] = PORTD_HOTPLUG_INT_STATUS
};

static const u32 hpd_status_i915[] = { /* i915 and valleyview are the same */
        [HPD_CRT] = CRT_HOTPLUG_INT_STATUS,
        [HPD_SDVO_B] = SDVOB_HOTPLUG_INT_STATUS_I915,
        [HPD_SDVO_C] = SDVOC_HOTPLUG_INT_STATUS_I915,
        [HPD_PORT_B] = PORTB_HOTPLUG_INT_STATUS,
        [HPD_PORT_C] = PORTC_HOTPLUG_INT_STATUS,
        [HPD_PORT_D] = PORTD_HOTPLUG_INT_STATUS
};

/* For display hotplug interrupt */
static void
ironlake_enable_display_irq(drm_i915_private_t *dev_priv, u32 mask)
{
        assert_spin_locked(&dev_priv->irq_lock);

        if (dev_priv->pc8.irqs_disabled) {
                WARN(1, "IRQs disabled\n");
                dev_priv->pc8.regsave.deimr &= ~mask;
                return;
        }

        if ((dev_priv->irq_mask & mask) != 0) {
                dev_priv->irq_mask &= ~mask;
                I915_WRITE(DEIMR, dev_priv->irq_mask);
                POSTING_READ(DEIMR);
        }
}

static void
ironlake_disable_display_irq(drm_i915_private_t *dev_priv, u32 mask)
{
        assert_spin_locked(&dev_priv->irq_lock);

        if (dev_priv->pc8.irqs_disabled) {
                WARN(1, "IRQs disabled\n");
                dev_priv->pc8.regsave.deimr |= mask;
                return;
        }

        if ((dev_priv->irq_mask & mask) != mask) {
                dev_priv->irq_mask |= mask;
                I915_WRITE(DEIMR, dev_priv->irq_mask);
                POSTING_READ(DEIMR);
        }
}

/**
 * ilk_update_gt_irq - update GTIMR
 * @dev_priv: driver private
 * @interrupt_mask: mask of interrupt bits to update
 * @enabled_irq_mask: mask of interrupt bits to enable
 */
static void ilk_update_gt_irq(struct drm_i915_private *dev_priv,
                              uint32_t interrupt_mask,
                              uint32_t enabled_irq_mask)
{
        assert_spin_locked(&dev_priv->irq_lock);

        if (dev_priv->pc8.irqs_disabled) {
                WARN(1, "IRQs disabled\n");
                dev_priv->pc8.regsave.gtimr &= ~interrupt_mask;
                dev_priv->pc8.regsave.gtimr |= (~enabled_irq_mask &
                                                interrupt_mask);
                return;
        }

        dev_priv->gt_irq_mask &= ~interrupt_mask;
        dev_priv->gt_irq_mask |= (~enabled_irq_mask & interrupt_mask);
        I915_WRITE(GTIMR, dev_priv->gt_irq_mask);
        POSTING_READ(GTIMR);
}

void ilk_enable_gt_irq(struct drm_i915_private *dev_priv, uint32_t mask)
{
        ilk_update_gt_irq(dev_priv, mask, mask);
}

void ilk_disable_gt_irq(struct drm_i915_private *dev_priv, uint32_t mask)
{
        ilk_update_gt_irq(dev_priv, mask, 0);
}

/**
  * snb_update_pm_irq - update GEN6_PMIMR
  * @dev_priv: driver private
  * @interrupt_mask: mask of interrupt bits to update
  * @enabled_irq_mask: mask of interrupt bits to enable
  */
static void snb_update_pm_irq(struct drm_i915_private *dev_priv,
                              uint32_t interrupt_mask,
                              uint32_t enabled_irq_mask)
{
        uint32_t new_val;

        assert_spin_locked(&dev_priv->irq_lock);

        if (dev_priv->pc8.irqs_disabled) {
                WARN(1, "IRQs disabled\n");
                dev_priv->pc8.regsave.gen6_pmimr &= ~interrupt_mask;
                dev_priv->pc8.regsave.gen6_pmimr |= (~enabled_irq_mask &
                                                     interrupt_mask);
                return;
        }

        new_val = dev_priv->pm_irq_mask;
        new_val &= ~interrupt_mask;
        new_val |= (~enabled_irq_mask & interrupt_mask);

        if (new_val != dev_priv->pm_irq_mask) {
                dev_priv->pm_irq_mask = new_val;
                I915_WRITE(GEN6_PMIMR, dev_priv->pm_irq_mask);
                POSTING_READ(GEN6_PMIMR);
        }
}

void snb_enable_pm_irq(struct drm_i915_private *dev_priv, uint32_t mask)
{
        snb_update_pm_irq(dev_priv, mask, mask);
}

void snb_disable_pm_irq(struct drm_i915_private *dev_priv, uint32_t mask)
{
        snb_update_pm_irq(dev_priv, mask, 0);
}

static bool ivb_can_enable_err_int(struct drm_device *dev)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct intel_crtc *crtc;
        enum pipe pipe;

        assert_spin_locked(&dev_priv->irq_lock);

        for_each_pipe(pipe) {
                crtc = to_intel_crtc(dev_priv->pipe_to_crtc_mapping[pipe]);

                if (crtc->cpu_fifo_underrun_disabled)
                        return false;
        }

        return true;
}

static bool cpt_can_enable_serr_int(struct drm_device *dev)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        enum pipe pipe;
        struct intel_crtc *crtc;

        assert_spin_locked(&dev_priv->irq_lock);

        for_each_pipe(pipe) {
                crtc = to_intel_crtc(dev_priv->pipe_to_crtc_mapping[pipe]);

                if (crtc->pch_fifo_underrun_disabled)
                        return false;
        }

        return true;
}

static void ironlake_set_fifo_underrun_reporting(struct drm_device *dev,
                                                 enum pipe pipe, bool enable)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        uint32_t bit = (pipe == PIPE_A) ? DE_PIPEA_FIFO_UNDERRUN :
                                          DE_PIPEB_FIFO_UNDERRUN;

        if (enable)
                ironlake_enable_display_irq(dev_priv, bit);
        else
                ironlake_disable_display_irq(dev_priv, bit);
}

static void ivybridge_set_fifo_underrun_reporting(struct drm_device *dev,
                                                  enum pipe pipe, bool enable)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        if (enable) {
                I915_WRITE(GEN7_ERR_INT, ERR_INT_FIFO_UNDERRUN(pipe));

                if (!ivb_can_enable_err_int(dev))
                        return;

                ironlake_enable_display_irq(dev_priv, DE_ERR_INT_IVB);
        } else {
                bool was_enabled = !(I915_READ(DEIMR) & DE_ERR_INT_IVB);

                /* Change the state _after_ we've read out the current one. */
                ironlake_disable_display_irq(dev_priv, DE_ERR_INT_IVB);

                if (!was_enabled &&
                    (I915_READ(GEN7_ERR_INT) & ERR_INT_FIFO_UNDERRUN(pipe))) {
                        DRM_DEBUG_KMS("uncleared fifo underrun on pipe %c\n",
                                      pipe_name(pipe));
                }
        }
}

/**
 * ibx_display_interrupt_update - update SDEIMR
 * @dev_priv: driver private
 * @interrupt_mask: mask of interrupt bits to update
 * @enabled_irq_mask: mask of interrupt bits to enable
 */
static void ibx_display_interrupt_update(struct drm_i915_private *dev_priv,
                                         uint32_t interrupt_mask,
                                         uint32_t enabled_irq_mask)
{
        uint32_t sdeimr = I915_READ(SDEIMR);
        sdeimr &= ~interrupt_mask;
        sdeimr |= (~enabled_irq_mask & interrupt_mask);

        assert_spin_locked(&dev_priv->irq_lock);

        if (dev_priv->pc8.irqs_disabled &&
            (interrupt_mask & SDE_HOTPLUG_MASK_CPT)) {
                WARN(1, "IRQs disabled\n");
                dev_priv->pc8.regsave.sdeimr &= ~interrupt_mask;
                dev_priv->pc8.regsave.sdeimr |= (~enabled_irq_mask &
                                                 interrupt_mask);
                return;
        }

        I915_WRITE(SDEIMR, sdeimr);
        POSTING_READ(SDEIMR);
}
#define ibx_enable_display_interrupt(dev_priv, bits) \
        ibx_display_interrupt_update((dev_priv), (bits), (bits))
#define ibx_disable_display_interrupt(dev_priv, bits) \
        ibx_display_interrupt_update((dev_priv), (bits), 0)

static void ibx_set_fifo_underrun_reporting(struct drm_device *dev,
                                            enum transcoder pch_transcoder,
                                            bool enable)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        uint32_t bit = (pch_transcoder == TRANSCODER_A) ?
                       SDE_TRANSA_FIFO_UNDER : SDE_TRANSB_FIFO_UNDER;

        if (enable)
                ibx_enable_display_interrupt(dev_priv, bit);
        else
                ibx_disable_display_interrupt(dev_priv, bit);
}

static void cpt_set_fifo_underrun_reporting(struct drm_device *dev,
                                            enum transcoder pch_transcoder,
                                            bool enable)
{
        struct drm_i915_private *dev_priv = dev->dev_private;

        if (enable) {
                I915_WRITE(SERR_INT,
                           SERR_INT_TRANS_FIFO_UNDERRUN(pch_transcoder));

                if (!cpt_can_enable_serr_int(dev))
                        return;

                ibx_enable_display_interrupt(dev_priv, SDE_ERROR_CPT);
        } else {
                uint32_t tmp = I915_READ(SERR_INT);
                bool was_enabled = !(I915_READ(SDEIMR) & SDE_ERROR_CPT);

                /* Change the state _after_ we've read out the current one. */
                ibx_disable_display_interrupt(dev_priv, SDE_ERROR_CPT);

                if (!was_enabled &&
                    (tmp & SERR_INT_TRANS_FIFO_UNDERRUN(pch_transcoder))) {
                        DRM_DEBUG_KMS("uncleared pch fifo underrun on pch transcoder %c\n",
                                      transcoder_name(pch_transcoder));
                }
        }
}

/**
 * intel_set_cpu_fifo_underrun_reporting - enable/disable FIFO underrun messages
 * @dev: drm device
 * @pipe: pipe
 * @enable: true if we want to report FIFO underrun errors, false otherwise
 *
 * This function makes us disable or enable CPU fifo underruns for a specific
 * pipe. Notice that on some Gens (e.g. IVB, HSW), disabling FIFO underrun
 * reporting for one pipe may also disable all the other CPU error interruts for
 * the other pipes, due to the fact that there's just one interrupt mask/enable
 * bit for all the pipes.
 *
 * Returns the previous state of underrun reporting.
 */
bool intel_set_cpu_fifo_underrun_reporting(struct drm_device *dev,
                                           enum pipe pipe, bool enable)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct drm_crtc *crtc = dev_priv->pipe_to_crtc_mapping[pipe];
        struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
        unsigned long flags;
        bool ret;

        spin_lock_irqsave(&dev_priv->irq_lock, flags);

        ret = !intel_crtc->cpu_fifo_underrun_disabled;

        if (enable == ret)
                goto done;

        intel_crtc->cpu_fifo_underrun_disabled = !enable;

        if (IS_GEN5(dev) || IS_GEN6(dev))
                ironlake_set_fifo_underrun_reporting(dev, pipe, enable);
        else if (IS_GEN7(dev))
                ivybridge_set_fifo_underrun_reporting(dev, pipe, enable);

done:
        spin_unlock_irqrestore(&dev_priv->irq_lock, flags);
        return ret;
}

/**
 * intel_set_pch_fifo_underrun_reporting - enable/disable FIFO underrun messages
 * @dev: drm device
 * @pch_transcoder: the PCH transcoder (same as pipe on IVB and older)
 * @enable: true if we want to report FIFO underrun errors, false otherwise
 *
 * This function makes us disable or enable PCH fifo underruns for a specific
 * PCH transcoder. Notice that on some PCHs (e.g. CPT/PPT), disabling FIFO
 * underrun reporting for one transcoder may also disable all the other PCH
 * error interruts for the other transcoders, due to the fact that there's just
 * one interrupt mask/enable bit for all the transcoders.
 *
 * Returns the previous state of underrun reporting.
 */
bool intel_set_pch_fifo_underrun_reporting(struct drm_device *dev,
                                           enum transcoder pch_transcoder,
                                           bool enable)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct drm_crtc *crtc = dev_priv->pipe_to_crtc_mapping[pch_transcoder];
        struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
        unsigned long flags;
        bool ret;

        /*
         * NOTE: Pre-LPT has a fixed cpu pipe -> pch transcoder mapping, but LPT
         * has only one pch transcoder A that all pipes can use. To avoid racy
         * pch transcoder -> pipe lookups from interrupt code simply store the
         * underrun statistics in crtc A. Since we never expose this anywhere
         * nor use it outside of the fifo underrun code here using the "wrong"
         * crtc on LPT won't cause issues.
         */

        spin_lock_irqsave(&dev_priv->irq_lock, flags);

        ret = !intel_crtc->pch_fifo_underrun_disabled;

        if (enable == ret)
                goto done;

        intel_crtc->pch_fifo_underrun_disabled = !enable;

        if (HAS_PCH_IBX(dev))
                ibx_set_fifo_underrun_reporting(dev, pch_transcoder, enable);
        else
                cpt_set_fifo_underrun_reporting(dev, pch_transcoder, enable);

done:
        spin_unlock_irqrestore(&dev_priv->irq_lock, flags);
        return ret;
}


void
i915_enable_pipestat(drm_i915_private_t *dev_priv, int pipe, u32 mask)
{
        u32 reg = PIPESTAT(pipe);
        u32 pipestat = I915_READ(reg) & 0x7fff0000;

        assert_spin_locked(&dev_priv->irq_lock);

        if ((pipestat & mask) == mask)
                return;

        /* Enable the interrupt, clear any pending status */
        pipestat |= mask | (mask >> 16);
        I915_WRITE(reg, pipestat);
        POSTING_READ(reg);
}

void
i915_disable_pipestat(drm_i915_private_t *dev_priv, int pipe, u32 mask)
{
        u32 reg = PIPESTAT(pipe);
        u32 pipestat = I915_READ(reg) & 0x7fff0000;

        assert_spin_locked(&dev_priv->irq_lock);

        if ((pipestat & mask) == 0)
                return;

        pipestat &= ~mask;
        I915_WRITE(reg, pipestat);
        POSTING_READ(reg);
}

/**
 * i915_enable_asle_pipestat - enable ASLE pipestat for OpRegion
 */
static void i915_enable_asle_pipestat(struct drm_device *dev)
{
        drm_i915_private_t *dev_priv = dev->dev_private;
        unsigned long irqflags;

        if (!dev_priv->opregion.asle || !IS_MOBILE(dev))
                return;

        spin_lock_irqsave(&dev_priv->irq_lock, irqflags);

        i915_enable_pipestat(dev_priv, 1, PIPE_LEGACY_BLC_EVENT_ENABLE);
        if (INTEL_INFO(dev)->gen >= 4)
                i915_enable_pipestat(dev_priv, 0, PIPE_LEGACY_BLC_EVENT_ENABLE);

        spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
}

/**
 * i915_pipe_enabled - check if a pipe is enabled
 * @dev: DRM device
 * @pipe: pipe to check
 *
 * Reading certain registers when the pipe is disabled can hang the chip.
 * Use this routine to make sure the PLL is running and the pipe is active
 * before reading such registers if unsure.
 */
static int
i915_pipe_enabled(struct drm_device *dev, int pipe)
{
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;

        if (drm_core_check_feature(dev, DRIVER_MODESET)) {
                /* Locking is horribly broken here, but whatever. */
                struct drm_crtc *crtc = dev_priv->pipe_to_crtc_mapping[pipe];
                struct intel_crtc *intel_crtc = to_intel_crtc(crtc);

                return intel_crtc->active;
        } else {
                return I915_READ(PIPECONF(pipe)) & PIPECONF_ENABLE;
        }
}

/* Called from drm generic code, passed a 'crtc', which
 * we use as a pipe index
 */
static u32 i915_get_vblank_counter(struct drm_device *dev, int pipe)
{
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
        unsigned long high_frame;
        unsigned long low_frame;
        u32 high1, high2, low;

        if (!i915_pipe_enabled(dev, pipe)) {
                DRM_DEBUG_DRIVER("trying to get vblank count for disabled "
                                "pipe %c\n", pipe_name(pipe));
                return 0;
        }

        high_frame = PIPEFRAME(pipe);
        low_frame = PIPEFRAMEPIXEL(pipe);

        /*
         * High & low register fields aren't synchronized, so make sure
         * we get a low value that's stable across two reads of the high
         * register.
         */
        do {
                high1 = I915_READ(high_frame) & PIPE_FRAME_HIGH_MASK;
                low   = I915_READ(low_frame)  & PIPE_FRAME_LOW_MASK;
                high2 = I915_READ(high_frame) & PIPE_FRAME_HIGH_MASK;
        } while (high1 != high2);

        high1 >>= PIPE_FRAME_HIGH_SHIFT;
        low >>= PIPE_FRAME_LOW_SHIFT;
        return (high1 << 8) | low;
}

static u32 gm45_get_vblank_counter(struct drm_device *dev, int pipe)
{
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
        int reg = PIPE_FRMCOUNT_GM45(pipe);

        if (!i915_pipe_enabled(dev, pipe)) {
                DRM_DEBUG_DRIVER("trying to get vblank count for disabled "
                                 "pipe %c\n", pipe_name(pipe));
                return 0;
        }

        return I915_READ(reg);
}

static int i915_get_crtc_scanoutpos(struct drm_device *dev, int pipe,
                             int *vpos, int *hpos)
{
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
        u32 vbl = 0, position = 0;
        int vbl_start, vbl_end, htotal, vtotal;
        bool in_vbl = true;
        int ret = 0;
        enum transcoder cpu_transcoder = intel_pipe_to_cpu_transcoder(dev_priv,
                                                                      pipe);

        if (!i915_pipe_enabled(dev, pipe)) {
                DRM_DEBUG_DRIVER("trying to get scanoutpos for disabled "
                                 "pipe %c\n", pipe_name(pipe));
                return 0;
        }

        /* Get vtotal. */
        vtotal = 1 + ((I915_READ(VTOTAL(cpu_transcoder)) >> 16) & 0x1fff);

        if (INTEL_INFO(dev)->gen >= 4) {
                /* No obvious pixelcount register. Only query vertical
                 * scanout position from Display scan line register.
                 */
                position = I915_READ(PIPEDSL(pipe));

                /* Decode into vertical scanout position. Don't have
                 * horizontal scanout position.
                 */
                *vpos = position & 0x1fff;
                *hpos = 0;
        } else {
                /* Have access to pixelcount since start of frame.
                 * We can split this into vertical and horizontal
                 * scanout position.
                 */
                position = (I915_READ(PIPEFRAMEPIXEL(pipe)) & PIPE_PIXEL_MASK) >> PIPE_PIXEL_SHIFT;

                htotal = 1 + ((I915_READ(HTOTAL(cpu_transcoder)) >> 16) & 0x1fff);
                *vpos = position / htotal;
                *hpos = position - (*vpos * htotal);
        }

        /* Query vblank area. */
        vbl = I915_READ(VBLANK(cpu_transcoder));

        /* Test position against vblank region. */
        vbl_start = vbl & 0x1fff;
        vbl_end = (vbl >> 16) & 0x1fff;

        if ((*vpos < vbl_start) || (*vpos > vbl_end))
                in_vbl = false;

        /* Inside "upper part" of vblank area? Apply corrective offset: */
        if (in_vbl && (*vpos >= vbl_start))
                *vpos = *vpos - vtotal;

        /* Readouts valid? */
        if (vbl > 0)
                ret |= DRM_SCANOUTPOS_VALID | DRM_SCANOUTPOS_ACCURATE;

        /* In vblank? */
        if (in_vbl)
                ret |= DRM_SCANOUTPOS_INVBL;

        return ret;
}

static int i915_get_vblank_timestamp(struct drm_device *dev, int pipe,
                              int *max_error,
                              struct timeval *vblank_time,
                              unsigned flags)
{
        struct drm_crtc *crtc;

        if (pipe < 0 || pipe >= INTEL_INFO(dev)->num_pipes) {
                DRM_ERROR("Invalid crtc %d\n", pipe);
                return -EINVAL;
        }

        /* Get drm_crtc to timestamp: */
        crtc = intel_get_crtc_for_pipe(dev, pipe);
        if (crtc == NULL) {
                DRM_ERROR("Invalid crtc %d\n", pipe);
                return -EINVAL;
        }

        if (!crtc->enabled) {
                DRM_DEBUG_KMS("crtc %d is disabled\n", pipe);
                return -EBUSY;
        }

        /* Helper routine in DRM core does all the work: */
        return drm_calc_vbltimestamp_from_scanoutpos(dev, pipe, max_error,
                                                     vblank_time, flags,
                                                     crtc);
}

static int intel_hpd_irq_event(struct drm_device *dev, struct drm_connector *connector)
{
        enum drm_connector_status old_status;

        WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
        old_status = connector->status;

        connector->status = connector->funcs->detect(connector, false);
        DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %d to %d\n",
                      connector->base.id,
                      drm_get_connector_name(connector),
                      old_status, connector->status);
        return (old_status != connector->status);
}

/*
 * Handle hotplug events outside the interrupt handler proper.
 */
#define I915_REENABLE_HOTPLUG_DELAY (2*60*1000)

static void i915_hotplug_work_func(struct work_struct *work)
{
        drm_i915_private_t *dev_priv = container_of(work, drm_i915_private_t,
                                                    hotplug_work);
        struct drm_device *dev = dev_priv->dev;
        struct drm_mode_config *mode_config = &dev->mode_config;
        struct intel_connector *intel_connector;
        struct intel_encoder *intel_encoder;
        struct drm_connector *connector;
        unsigned long irqflags;
        bool hpd_disabled = false;
        bool changed = false;
        u32 hpd_event_bits;

        /* HPD irq before everything is fully set up. */
        if (!dev_priv->enable_hotplug_processing)
                return;

        mutex_lock(&mode_config->mutex);
        DRM_DEBUG_KMS("running encoder hotplug functions\n");

        spin_lock_irqsave(&dev_priv->irq_lock, irqflags);

        hpd_event_bits = dev_priv->hpd_event_bits;
        dev_priv->hpd_event_bits = 0;
        list_for_each_entry(connector, &mode_config->connector_list, head) {
                intel_connector = to_intel_connector(connector);
                intel_encoder = intel_connector->encoder;
                if (intel_encoder->hpd_pin > HPD_NONE &&
                    dev_priv->hpd_stats[intel_encoder->hpd_pin].hpd_mark == HPD_MARK_DISABLED &&
                    connector->polled == DRM_CONNECTOR_POLL_HPD) {
                        DRM_INFO("HPD interrupt storm detected on connector %s: "
                                 "switching from hotplug detection to polling\n",
                                drm_get_connector_name(connector));
                        dev_priv->hpd_stats[intel_encoder->hpd_pin].hpd_mark = HPD_DISABLED;
                        connector->polled = DRM_CONNECTOR_POLL_CONNECT
                                | DRM_CONNECTOR_POLL_DISCONNECT;
                        hpd_disabled = true;
                }
                if (hpd_event_bits & (1 << intel_encoder->hpd_pin)) {
                        DRM_DEBUG_KMS("Connector %s (pin %i) received hotplug event.\n",
                                      drm_get_connector_name(connector), intel_encoder->hpd_pin);
                }
        }
         /* if there were no outputs to poll, poll was disabled,
          * therefore make sure it's enabled when disabling HPD on
          * some connectors */
        if (hpd_disabled) {
                drm_kms_helper_poll_enable(dev);
                mod_timer(&dev_priv->hotplug_reenable_timer,
                          jiffies + msecs_to_jiffies(I915_REENABLE_HOTPLUG_DELAY));
        }

        spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);

        list_for_each_entry(connector, &mode_config->connector_list, head) {
                intel_connector = to_intel_connector(connector);
                intel_encoder = intel_connector->encoder;
                if (hpd_event_bits & (1 << intel_encoder->hpd_pin)) {
                        if (intel_encoder->hot_plug)
                                intel_encoder->hot_plug(intel_encoder);
                        if (intel_hpd_irq_event(dev, connector))
                                changed = true;
                }
        }
        mutex_unlock(&mode_config->mutex);

        if (changed)
                drm_kms_helper_hotplug_event(dev);
}

static void ironlake_rps_change_irq_handler(struct drm_device *dev)
{
        drm_i915_private_t *dev_priv = dev->dev_private;
        u32 busy_up, busy_down, max_avg, min_avg;
        u8 new_delay;

        spin_lock(&mchdev_lock);

        I915_WRITE16(MEMINTRSTS, I915_READ(MEMINTRSTS));

        new_delay = dev_priv->ips.cur_delay;

        I915_WRITE16(MEMINTRSTS, MEMINT_EVAL_CHG);
        busy_up = I915_READ(RCPREVBSYTUPAVG);
        busy_down = I915_READ(RCPREVBSYTDNAVG);
        max_avg = I915_READ(RCBMAXAVG);
        min_avg = I915_READ(RCBMINAVG);

        /* Handle RCS change request from hw */
        if (busy_up > max_avg) {
                if (dev_priv->ips.cur_delay != dev_priv->ips.max_delay)
                        new_delay = dev_priv->ips.cur_delay - 1;
                if (new_delay < dev_priv->ips.max_delay)
                        new_delay = dev_priv->ips.max_delay;
        } else if (busy_down < min_avg) {
                if (dev_priv->ips.cur_delay != dev_priv->ips.min_delay)
                        new_delay = dev_priv->ips.cur_delay + 1;
                if (new_delay > dev_priv->ips.min_delay)
                        new_delay = dev_priv->ips.min_delay;
        }

        if (ironlake_set_drps(dev, new_delay))
                dev_priv->ips.cur_delay = new_delay;

        spin_unlock(&mchdev_lock);

        return;
}

static void notify_ring(struct drm_device *dev,
                        struct intel_ring_buffer *ring)
{
        if (ring->obj == NULL)
                return;

        trace_i915_gem_request_complete(ring, ring->get_seqno(ring, false));

        wake_up_all(&ring->irq_queue);
        i915_queue_hangcheck(dev);
}

static void gen6_pm_rps_work(struct work_struct *work)
{
        drm_i915_private_t *dev_priv = container_of(work, drm_i915_private_t,
                                                    rps.work);
        u32 pm_iir;
        u8 new_delay;

        spin_lock_irq(&dev_priv->irq_lock);
        pm_iir = dev_priv->rps.pm_iir;
        dev_priv->rps.pm_iir = 0;
        /* Make sure not to corrupt PMIMR state used by ringbuffer code */
        snb_enable_pm_irq(dev_priv, GEN6_PM_RPS_EVENTS);
        spin_unlock_irq(&dev_priv->irq_lock);

        /* Make sure we didn't queue anything we're not going to process. */
        WARN_ON(pm_iir & ~GEN6_PM_RPS_EVENTS);

        if ((pm_iir & GEN6_PM_RPS_EVENTS) == 0)
                return;

        mutex_lock(&dev_priv->rps.hw_lock);

        if (pm_iir & GEN6_PM_RP_UP_THRESHOLD) {
                new_delay = dev_priv->rps.cur_delay + 1;

                /*
                 * For better performance, jump directly
                 * to RPe if we're below it.
                 */
                if (IS_VALLEYVIEW(dev_priv->dev) &&
                    dev_priv->rps.cur_delay < dev_priv->rps.rpe_delay)
                        new_delay = dev_priv->rps.rpe_delay;
        } else
                new_delay = dev_priv->rps.cur_delay - 1;

        /* sysfs frequency interfaces may have snuck in while servicing the
         * interrupt
         */
        if (new_delay >= dev_priv->rps.min_delay &&
            new_delay <= dev_priv->rps.max_delay) {
                if (IS_VALLEYVIEW(dev_priv->dev))
                        valleyview_set_rps(dev_priv->dev, new_delay);
                else
                        gen6_set_rps(dev_priv->dev, new_delay);
        }

        if (IS_VALLEYVIEW(dev_priv->dev)) {
                /*
                 * On VLV, when we enter RC6 we may not be at the minimum
                 * voltage level, so arm a timer to check.  It should only
                 * fire when there's activity or once after we've entered
                 * RC6, and then won't be re-armed until the next RPS interrupt.
                 */
                mod_delayed_work(dev_priv->wq, &dev_priv->rps.vlv_work,
                                 msecs_to_jiffies(100));
        }

        mutex_unlock(&dev_priv->rps.hw_lock);
}


/**
 * ivybridge_parity_work - Workqueue called when a parity error interrupt
 * occurred.
 * @work: workqueue struct
 *
 * Doesn't actually do anything except notify userspace. As a consequence of
 * this event, userspace should try to remap the bad rows since statistically
 * it is likely the same row is more likely to go bad again.
 */
static void ivybridge_parity_work(struct work_struct *work)
{
        drm_i915_private_t *dev_priv = container_of(work, drm_i915_private_t,
                                                    l3_parity.error_work);
        u32 error_status, row, bank, subbank;
        char *parity_event[5];
        uint32_t misccpctl;
        unsigned long flags;

        /* We must turn off DOP level clock gating to access the L3 registers.
         * In order to prevent a get/put style interface, acquire struct mutex
         * any time we access those registers.
         */
        mutex_lock(&dev_priv->dev->struct_mutex);

        misccpctl = I915_READ(GEN7_MISCCPCTL);
        I915_WRITE(GEN7_MISCCPCTL, misccpctl & ~GEN7_DOP_CLOCK_GATE_ENABLE);
        POSTING_READ(GEN7_MISCCPCTL);

        error_status = I915_READ(GEN7_L3CDERRST1);
        row = GEN7_PARITY_ERROR_ROW(error_status);
        bank = GEN7_PARITY_ERROR_BANK(error_status);
        subbank = GEN7_PARITY_ERROR_SUBBANK(error_status);

        I915_WRITE(GEN7_L3CDERRST1, GEN7_PARITY_ERROR_VALID |
                                    GEN7_L3CDERRST1_ENABLE);
        POSTING_READ(GEN7_L3CDERRST1);

        I915_WRITE(GEN7_MISCCPCTL, misccpctl);

        spin_lock_irqsave(&dev_priv->irq_lock, flags);
        ilk_enable_gt_irq(dev_priv, GT_RENDER_L3_PARITY_ERROR_INTERRUPT);
        spin_unlock_irqrestore(&dev_priv->irq_lock, flags);

        mutex_unlock(&dev_priv->dev->struct_mutex);

        parity_event[0] = I915_L3_PARITY_UEVENT "=1";
        parity_event[1] = kasprintf(GFP_KERNEL, "ROW=%d", row);
        parity_event[2] = kasprintf(GFP_KERNEL, "BANK=%d", bank);
        parity_event[3] = kasprintf(GFP_KERNEL, "SUBBANK=%d", subbank);
        parity_event[4] = NULL;

        kobject_uevent_env(&dev_priv->dev->primary->kdev.kobj,
                           KOBJ_CHANGE, parity_event);

        DRM_DEBUG("Parity error: Row = %d, Bank = %d, Sub bank = %d.\n",
                  row, bank, subbank);

        kfree(parity_event[3]);
        kfree(parity_event[2]);
        kfree(parity_event[1]);
}

static void ivybridge_parity_error_irq_handler(struct drm_device *dev)
{
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;

        if (!HAS_L3_GPU_CACHE(dev))
                return;

        spin_lock(&dev_priv->irq_lock);
        ilk_disable_gt_irq(dev_priv, GT_RENDER_L3_PARITY_ERROR_INTERRUPT);
        spin_unlock(&dev_priv->irq_lock);

        queue_work(dev_priv->wq, &dev_priv->l3_parity.error_work);
}

static void ilk_gt_irq_handler(struct drm_device *dev,
                               struct drm_i915_private *dev_priv,
                               u32 gt_iir)
{
        if (gt_iir &
            (GT_RENDER_USER_INTERRUPT | GT_RENDER_PIPECTL_NOTIFY_INTERRUPT))
                notify_ring(dev, &dev_priv->ring[RCS]);
        if (gt_iir & ILK_BSD_USER_INTERRUPT)
                notify_ring(dev, &dev_priv->ring[VCS]);
}

static void snb_gt_irq_handler(struct drm_device *dev,
                               struct drm_i915_private *dev_priv,
                               u32 gt_iir)
{

        if (gt_iir &
            (GT_RENDER_USER_INTERRUPT | GT_RENDER_PIPECTL_NOTIFY_INTERRUPT))
                notify_ring(dev, &dev_priv->ring[RCS]);
        if (gt_iir & GT_BSD_USER_INTERRUPT)
                notify_ring(dev, &dev_priv->ring[VCS]);
        if (gt_iir & GT_BLT_USER_INTERRUPT)
                notify_ring(dev, &dev_priv->ring[BCS]);

        if (gt_iir & (GT_BLT_CS_ERROR_INTERRUPT |
                      GT_BSD_CS_ERROR_INTERRUPT |
                      GT_RENDER_CS_MASTER_ERROR_INTERRUPT)) {
                DRM_ERROR("GT error interrupt 0x%08x\n", gt_iir);
                i915_handle_error(dev, false);
        }

        if (gt_iir & GT_RENDER_L3_PARITY_ERROR_INTERRUPT)
                ivybridge_parity_error_irq_handler(dev);
}

#define HPD_STORM_DETECT_PERIOD 1000
#define HPD_STORM_THRESHOLD 5

static inline void intel_hpd_irq_handler(struct drm_device *dev,
                                         u32 hotplug_trigger,
                                         const u32 *hpd)
{
        drm_i915_private_t *dev_priv = dev->dev_private;
        int i;
        bool storm_detected = false;

        if (!hotplug_trigger)
                return;

        spin_lock(&dev_priv->irq_lock);
        for (i = 1; i < HPD_NUM_PINS; i++) {

                WARN(((hpd[i] & hotplug_trigger) &&
                      dev_priv->hpd_stats[i].hpd_mark != HPD_ENABLED),

                     "Received HPD interrupt although disabled\n");

                if (!(hpd[i] & hotplug_trigger) ||
                    dev_priv->hpd_stats[i].hpd_mark != HPD_ENABLED)
                        continue;

                dev_priv->hpd_event_bits |= (1 << i);
                if (!time_in_range(jiffies, dev_priv->hpd_stats[i].hpd_last_jiffies,
                                   dev_priv->hpd_stats[i].hpd_last_jiffies
                                   + msecs_to_jiffies(HPD_STORM_DETECT_PERIOD))) {
                        dev_priv->hpd_stats[i].hpd_last_jiffies = jiffies;
                        dev_priv->hpd_stats[i].hpd_cnt = 0;
                        DRM_DEBUG_KMS("Received HPD interrupt on PIN %d - cnt: 0\n", i);
                } else if (dev_priv->hpd_stats[i].hpd_cnt > HPD_STORM_THRESHOLD) {
                        dev_priv->hpd_stats[i].hpd_mark = HPD_MARK_DISABLED;
                        dev_priv->hpd_event_bits &= ~(1 << i);
                        DRM_DEBUG_KMS("HPD interrupt storm detected on PIN %d\n", i);
                        storm_detected = true;
                } else {
                        dev_priv->hpd_stats[i].hpd_cnt++;
                        DRM_DEBUG_KMS("Received HPD interrupt on PIN %d - cnt: %d\n", i,
                                      dev_priv->hpd_stats[i].hpd_cnt);
                }
        }

        if (storm_detected)
                dev_priv->display.hpd_irq_setup(dev);
        spin_unlock(&dev_priv->irq_lock);

        /*
         * Our hotplug handler can grab modeset locks (by calling down into the
         * fb helpers). Hence it must not be run on our own dev-priv->wq work
         * queue for otherwise the flush_work in the pageflip code will
         * deadlock.
         */
        schedule_work(&dev_priv->hotplug_work);
}

static void gmbus_irq_handler(struct drm_device *dev)
{
        struct drm_i915_private *dev_priv = (drm_i915_private_t *) dev->dev_private;

        wake_up_all(&dev_priv->gmbus_wait_queue);
}

static void dp_aux_irq_handler(struct drm_device *dev)
{
        struct drm_i915_private *dev_priv = (drm_i915_private_t *) dev->dev_private;

        wake_up_all(&dev_priv->gmbus_wait_queue);
}

/* The RPS events need forcewake, so we add them to a work queue and mask their
 * IMR bits until the work is done. Other interrupts can be processed without
 * the work queue. */
static void gen6_rps_irq_handler(struct drm_i915_private *dev_priv, u32 pm_iir)
{
        if (pm_iir & GEN6_PM_RPS_EVENTS) {
                spin_lock(&dev_priv->irq_lock);
                dev_priv->rps.pm_iir |= pm_iir & GEN6_PM_RPS_EVENTS;
                snb_disable_pm_irq(dev_priv, pm_iir & GEN6_PM_RPS_EVENTS);
                spin_unlock(&dev_priv->irq_lock);

                queue_work(dev_priv->wq, &dev_priv->rps.work);
        }

        if (HAS_VEBOX(dev_priv->dev)) {
                if (pm_iir & PM_VEBOX_USER_INTERRUPT)
                        notify_ring(dev_priv->dev, &dev_priv->ring[VECS]);

                if (pm_iir & PM_VEBOX_CS_ERROR_INTERRUPT) {
                        DRM_ERROR("VEBOX CS error interrupt 0x%08x\n", pm_iir);
                        i915_handle_error(dev_priv->dev, false);
                }
        }
}

static irqreturn_t valleyview_irq_handler(int irq, void *arg)
{
        struct drm_device *dev = (struct drm_device *) arg;
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
        u32 iir, gt_iir, pm_iir;
        irqreturn_t ret = IRQ_NONE;
        unsigned long irqflags;
        int pipe;
        u32 pipe_stats[I915_MAX_PIPES];

        atomic_inc(&dev_priv->irq_received);

        while (true) {
                iir = I915_READ(VLV_IIR);
                gt_iir = I915_READ(GTIIR);
                pm_iir = I915_READ(GEN6_PMIIR);

                if (gt_iir == 0 && pm_iir == 0 && iir == 0)
                        goto out;

                ret = IRQ_HANDLED;

                snb_gt_irq_handler(dev, dev_priv, gt_iir);

                spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
                for_each_pipe(pipe) {
                        int reg = PIPESTAT(pipe);
                        pipe_stats[pipe] = I915_READ(reg);

                        /*
                         * Clear the PIPE*STAT regs before the IIR
                         */
                        if (pipe_stats[pipe] & 0x8000ffff) {
                                if (pipe_stats[pipe] & PIPE_FIFO_UNDERRUN_STATUS)
                                        DRM_DEBUG_DRIVER("pipe %c underrun\n",
                                                         pipe_name(pipe));
                                I915_WRITE(reg, pipe_stats[pipe]);
                        }
                }
                spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);

                for_each_pipe(pipe) {
                        if (pipe_stats[pipe] & PIPE_VBLANK_INTERRUPT_STATUS)
                                drm_handle_vblank(dev, pipe);

                        if (pipe_stats[pipe] & PLANE_FLIPDONE_INT_STATUS_VLV) {
                                intel_prepare_page_flip(dev, pipe);
                                intel_finish_page_flip(dev, pipe);
                        }
                }

                /* Consume port.  Then clear IIR or we'll miss events */
                if (iir & I915_DISPLAY_PORT_INTERRUPT) {
                        u32 hotplug_status = I915_READ(PORT_HOTPLUG_STAT);
                        u32 hotplug_trigger = hotplug_status & HOTPLUG_INT_STATUS_I915;

                        DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
                                         hotplug_status);

                        intel_hpd_irq_handler(dev, hotplug_trigger, hpd_status_i915);

                        I915_WRITE(PORT_HOTPLUG_STAT, hotplug_status);
                        I915_READ(PORT_HOTPLUG_STAT);
                }

                if (pipe_stats[0] & PIPE_GMBUS_INTERRUPT_STATUS)
                        gmbus_irq_handler(dev);

                if (pm_iir)
                        gen6_rps_irq_handler(dev_priv, pm_iir);

                I915_WRITE(GTIIR, gt_iir);
                I915_WRITE(GEN6_PMIIR, pm_iir);
                I915_WRITE(VLV_IIR, iir);
        }

out:
        return ret;
}

static void ibx_irq_handler(struct drm_device *dev, u32 pch_iir)
{
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
        int pipe;
        u32 hotplug_trigger = pch_iir & SDE_HOTPLUG_MASK;

        intel_hpd_irq_handler(dev, hotplug_trigger, hpd_ibx);

        if (pch_iir & SDE_AUDIO_POWER_MASK) {
                int port = ffs((pch_iir & SDE_AUDIO_POWER_MASK) >>
                               SDE_AUDIO_POWER_SHIFT);
                DRM_DEBUG_DRIVER("PCH audio power change on port %d\n",
                                 port_name(port));
        }

        if (pch_iir & SDE_AUX_MASK)
                dp_aux_irq_handler(dev);

        if (pch_iir & SDE_GMBUS)
                gmbus_irq_handler(dev);

        if (pch_iir & SDE_AUDIO_HDCP_MASK)
                DRM_DEBUG_DRIVER("PCH HDCP audio interrupt\n");

        if (pch_iir & SDE_AUDIO_TRANS_MASK)
                DRM_DEBUG_DRIVER("PCH transcoder audio interrupt\n");

        if (pch_iir & SDE_POISON)
                DRM_ERROR("PCH poison interrupt\n");

        if (pch_iir & SDE_FDI_MASK)
                for_each_pipe(pipe)
                        DRM_DEBUG_DRIVER("  pipe %c FDI IIR: 0x%08x\n",
                                         pipe_name(pipe),
                                         I915_READ(FDI_RX_IIR(pipe)));

        if (pch_iir & (SDE_TRANSB_CRC_DONE | SDE_TRANSA_CRC_DONE))
                DRM_DEBUG_DRIVER("PCH transcoder CRC done interrupt\n");

        if (pch_iir & (SDE_TRANSB_CRC_ERR | SDE_TRANSA_CRC_ERR))
                DRM_DEBUG_DRIVER("PCH transcoder CRC error interrupt\n");

        if (pch_iir & SDE_TRANSA_FIFO_UNDER)
                if (intel_set_pch_fifo_underrun_reporting(dev, TRANSCODER_A,
                                                          false))
                        DRM_DEBUG_DRIVER("PCH transcoder A FIFO underrun\n");

        if (pch_iir & SDE_TRANSB_FIFO_UNDER)
                if (intel_set_pch_fifo_underrun_reporting(dev, TRANSCODER_B,
                                                          false))
                        DRM_DEBUG_DRIVER("PCH transcoder B FIFO underrun\n");
}

static void ivb_err_int_handler(struct drm_device *dev)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        u32 err_int = I915_READ(GEN7_ERR_INT);

        if (err_int & ERR_INT_POISON)
                DRM_ERROR("Poison interrupt\n");

        if (err_int & ERR_INT_FIFO_UNDERRUN_A)
                if (intel_set_cpu_fifo_underrun_reporting(dev, PIPE_A, false))
                        DRM_DEBUG_DRIVER("Pipe A FIFO underrun\n");

        if (err_int & ERR_INT_FIFO_UNDERRUN_B)
                if (intel_set_cpu_fifo_underrun_reporting(dev, PIPE_B, false))
                        DRM_DEBUG_DRIVER("Pipe B FIFO underrun\n");

        if (err_int & ERR_INT_FIFO_UNDERRUN_C)
                if (intel_set_cpu_fifo_underrun_reporting(dev, PIPE_C, false))
                        DRM_DEBUG_DRIVER("Pipe C FIFO underrun\n");

        I915_WRITE(GEN7_ERR_INT, err_int);
}

static void cpt_serr_int_handler(struct drm_device *dev)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        u32 serr_int = I915_READ(SERR_INT);

        if (serr_int & SERR_INT_POISON)
                DRM_ERROR("PCH poison interrupt\n");

        if (serr_int & SERR_INT_TRANS_A_FIFO_UNDERRUN)
                if (intel_set_pch_fifo_underrun_reporting(dev, TRANSCODER_A,
                                                          false))
                        DRM_DEBUG_DRIVER("PCH transcoder A FIFO underrun\n");

        if (serr_int & SERR_INT_TRANS_B_FIFO_UNDERRUN)
                if (intel_set_pch_fifo_underrun_reporting(dev, TRANSCODER_B,
                                                          false))
                        DRM_DEBUG_DRIVER("PCH transcoder B FIFO underrun\n");

        if (serr_int & SERR_INT_TRANS_C_FIFO_UNDERRUN)
                if (intel_set_pch_fifo_underrun_reporting(dev, TRANSCODER_C,
                                                          false))
                        DRM_DEBUG_DRIVER("PCH transcoder C FIFO underrun\n");

        I915_WRITE(SERR_INT, serr_int);
}

static void cpt_irq_handler(struct drm_device *dev, u32 pch_iir)
{
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
        int pipe;
        u32 hotplug_trigger = pch_iir & SDE_HOTPLUG_MASK_CPT;

        intel_hpd_irq_handler(dev, hotplug_trigger, hpd_cpt);

        if (pch_iir & SDE_AUDIO_POWER_MASK_CPT) {
                int port = ffs((pch_iir & SDE_AUDIO_POWER_MASK_CPT) >>
                               SDE_AUDIO_POWER_SHIFT_CPT);
                DRM_DEBUG_DRIVER("PCH audio power change on port %c\n",
                                 port_name(port));
        }

        if (pch_iir & SDE_AUX_MASK_CPT)
                dp_aux_irq_handler(dev);

        if (pch_iir & SDE_GMBUS_CPT)
                gmbus_irq_handler(dev);

        if (pch_iir & SDE_AUDIO_CP_REQ_CPT)
                DRM_DEBUG_DRIVER("Audio CP request interrupt\n");

        if (pch_iir & SDE_AUDIO_CP_CHG_CPT)
                DRM_DEBUG_DRIVER("Audio CP change interrupt\n");

        if (pch_iir & SDE_FDI_MASK_CPT)
                for_each_pipe(pipe)
                        DRM_DEBUG_DRIVER("  pipe %c FDI IIR: 0x%08x\n",
                                         pipe_name(pipe),
                                         I915_READ(FDI_RX_IIR(pipe)));

        if (pch_iir & SDE_ERROR_CPT)
                cpt_serr_int_handler(dev);
}

static void ilk_display_irq_handler(struct drm_device *dev, u32 de_iir)
{
        struct drm_i915_private *dev_priv = dev->dev_private;

        if (de_iir & DE_AUX_CHANNEL_A)
                dp_aux_irq_handler(dev);

        if (de_iir & DE_GSE)
                intel_opregion_asle_intr(dev);

        if (de_iir & DE_PIPEA_VBLANK)
                drm_handle_vblank(dev, 0);

        if (de_iir & DE_PIPEB_VBLANK)
                drm_handle_vblank(dev, 1);

        if (de_iir & DE_POISON)
                DRM_ERROR("Poison interrupt\n");

        if (de_iir & DE_PIPEA_FIFO_UNDERRUN)
                if (intel_set_cpu_fifo_underrun_reporting(dev, PIPE_A, false))
                        DRM_DEBUG_DRIVER("Pipe A FIFO underrun\n");

        if (de_iir & DE_PIPEB_FIFO_UNDERRUN)
                if (intel_set_cpu_fifo_underrun_reporting(dev, PIPE_B, false))
                        DRM_DEBUG_DRIVER("Pipe B FIFO underrun\n");

        if (de_iir & DE_PLANEA_FLIP_DONE) {
                intel_prepare_page_flip(dev, 0);
                intel_finish_page_flip_plane(dev, 0);
        }

        if (de_iir & DE_PLANEB_FLIP_DONE) {
                intel_prepare_page_flip(dev, 1);
                intel_finish_page_flip_plane(dev, 1);
        }

        /* check event from PCH */
        if (de_iir & DE_PCH_EVENT) {
                u32 pch_iir = I915_READ(SDEIIR);

                if (HAS_PCH_CPT(dev))
                        cpt_irq_handler(dev, pch_iir);
                else
                        ibx_irq_handler(dev, pch_iir);

                /* should clear PCH hotplug event before clear CPU irq */
                I915_WRITE(SDEIIR, pch_iir);
        }

        if (IS_GEN5(dev) && de_iir & DE_PCU_EVENT)
                ironlake_rps_change_irq_handler(dev);
}

static void ivb_display_irq_handler(struct drm_device *dev, u32 de_iir)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        int i;

        if (de_iir & DE_ERR_INT_IVB)
                ivb_err_int_handler(dev);

        if (de_iir & DE_AUX_CHANNEL_A_IVB)
                dp_aux_irq_handler(dev);

        if (de_iir & DE_GSE_IVB)
                intel_opregion_asle_intr(dev);

        for (i = 0; i < 3; i++) {
                if (de_iir & (DE_PIPEA_VBLANK_IVB << (5 * i)))
                        drm_handle_vblank(dev, i);
                if (de_iir & (DE_PLANEA_FLIP_DONE_IVB << (5 * i))) {
                        intel_prepare_page_flip(dev, i);
                        intel_finish_page_flip_plane(dev, i);
                }
        }

        /* check event from PCH */
        if (!HAS_PCH_NOP(dev) && (de_iir & DE_PCH_EVENT_IVB)) {
                u32 pch_iir = I915_READ(SDEIIR);

                cpt_irq_handler(dev, pch_iir);

                /* clear PCH hotplug event before clear CPU irq */
                I915_WRITE(SDEIIR, pch_iir);
        }
}

static irqreturn_t ironlake_irq_handler(int irq, void *arg)
{
        struct drm_device *dev = (struct drm_device *) arg;
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
        u32 de_iir, gt_iir, de_ier, sde_ier = 0;
        irqreturn_t ret = IRQ_NONE;
        bool err_int_reenable = false;

        atomic_inc(&dev_priv->irq_received);

        /* We get interrupts on unclaimed registers, so check for this before we
         * do any I915_{READ,WRITE}. */
        intel_uncore_check_errors(dev);

        /* disable master interrupt before clearing iir  */
        de_ier = I915_READ(DEIER);
        I915_WRITE(DEIER, de_ier & ~DE_MASTER_IRQ_CONTROL);
        POSTING_READ(DEIER);

        /* Disable south interrupts. We'll only write to SDEIIR once, so further
         * interrupts will will be stored on its back queue, and then we'll be
         * able to process them after we restore SDEIER (as soon as we restore
         * it, we'll get an interrupt if SDEIIR still has something to process
         * due to its back queue). */
        if (!HAS_PCH_NOP(dev)) {
                sde_ier = I915_READ(SDEIER);
                I915_WRITE(SDEIER, 0);
                POSTING_READ(SDEIER);
        }

        /* On Haswell, also mask ERR_INT because we don't want to risk
         * generating "unclaimed register" interrupts from inside the interrupt
         * handler. */
        if (IS_HASWELL(dev)) {
                spin_lock(&dev_priv->irq_lock);
                err_int_reenable = ~dev_priv->irq_mask & DE_ERR_INT_IVB;
                if (err_int_reenable)
                        ironlake_disable_display_irq(dev_priv, DE_ERR_INT_IVB);
                spin_unlock(&dev_priv->irq_lock);
        }

        gt_iir = I915_READ(GTIIR);
        if (gt_iir) {
                if (INTEL_INFO(dev)->gen >= 6)
                        snb_gt_irq_handler(dev, dev_priv, gt_iir);
                else
                        ilk_gt_irq_handler(dev, dev_priv, gt_iir);
                I915_WRITE(GTIIR, gt_iir);
                ret = IRQ_HANDLED;
        }

        de_iir = I915_READ(DEIIR);
        if (de_iir) {
                if (INTEL_INFO(dev)->gen >= 7)
                        ivb_display_irq_handler(dev, de_iir);
                else
                        ilk_display_irq_handler(dev, de_iir);
                I915_WRITE(DEIIR, de_iir);
                ret = IRQ_HANDLED;
        }

        if (INTEL_INFO(dev)->gen >= 6) {
                u32 pm_iir = I915_READ(GEN6_PMIIR);
                if (pm_iir) {
                        gen6_rps_irq_handler(dev_priv, pm_iir);
                        I915_WRITE(GEN6_PMIIR, pm_iir);
                        ret = IRQ_HANDLED;
                }
        }

        if (err_int_reenable) {
                spin_lock(&dev_priv->irq_lock);
                if (ivb_can_enable_err_int(dev))
                        ironlake_enable_display_irq(dev_priv, DE_ERR_INT_IVB);
                spin_unlock(&dev_priv->irq_lock);
        }

        I915_WRITE(DEIER, de_ier);
        POSTING_READ(DEIER);
        if (!HAS_PCH_NOP(dev)) {
                I915_WRITE(SDEIER, sde_ier);
                POSTING_READ(SDEIER);
        }

        return ret;
}

static void i915_error_wake_up(struct drm_i915_private *dev_priv,
                               bool reset_completed)
{
        struct intel_ring_buffer *ring;
        int i;

        /*
         * Notify all waiters for GPU completion events that reset state has
         * been changed, and that they need to restart their wait after
         * checking for potential errors (and bail out to drop locks if there is
         * a gpu reset pending so that i915_error_work_func can acquire them).
         */

        /* Wake up __wait_seqno, potentially holding dev->struct_mutex. */
        for_each_ring(ring, dev_priv, i)
                wake_up_all(&ring->irq_queue);

        /* Wake up intel_crtc_wait_for_pending_flips, holding crtc->mutex. */
        wake_up_all(&dev_priv->pending_flip_queue);

        /*
         * Signal tasks blocked in i915_gem_wait_for_error that the pending
         * reset state is cleared.
         */
        if (reset_completed)
                wake_up_all(&dev_priv->gpu_error.reset_queue);
}

/**
 * i915_error_work_func - do process context error handling work
 * @work: work struct
 *
 * Fire an error uevent so userspace can see that a hang or error
 * was detected.
 */
static void i915_error_work_func(struct work_struct *work)
{
        struct i915_gpu_error *error = container_of(work, struct i915_gpu_error,
                                                    work);
        drm_i915_private_t *dev_priv = container_of(error, drm_i915_private_t,
                                                    gpu_error);
        struct drm_device *dev = dev_priv->dev;
        char *error_event[] = { I915_ERROR_UEVENT "=1", NULL };
        char *reset_event[] = { I915_RESET_UEVENT "=1", NULL };
        char *reset_done_event[] = { I915_ERROR_UEVENT "=0", NULL };
        int ret;

        kobject_uevent_env(&dev->primary->kdev.kobj, KOBJ_CHANGE, error_event);

        /*
         * Note that there's only one work item which does gpu resets, so we
         * need not worry about concurrent gpu resets potentially incrementing
         * error->reset_counter twice. We only need to take care of another
         * racing irq/hangcheck declaring the gpu dead for a second time. A
         * quick check for that is good enough: schedule_work ensures the
         * correct ordering between hang detection and this work item, and since
         * the reset in-progress bit is only ever set by code outside of this
         * work we don't need to worry about any other races.
         */
        if (i915_reset_in_progress(error) && !i915_terminally_wedged(error)) {
                DRM_DEBUG_DRIVER("resetting chip\n");
                kobject_uevent_env(&dev->primary->kdev.kobj, KOBJ_CHANGE,
                                   reset_event);

                /*
                 * All state reset _must_ be completed before we update the
                 * reset counter, for otherwise waiters might miss the reset
                 * pending state and not properly drop locks, resulting in
                 * deadlocks with the reset work.
                 */
                ret = i915_reset(dev);

                intel_display_handle_reset(dev);

                if (ret == 0) {
                        /*
                         * After all the gem state is reset, increment the reset
                         * counter and wake up everyone waiting for the reset to
                         * complete.
                         *
                         * Since unlock operations are a one-sided barrier only,
                         * we need to insert a barrier here to order any seqno
                         * updates before
                         * the counter increment.
                         */
                        smp_mb__before_atomic_inc();
                        atomic_inc(&dev_priv->gpu_error.reset_counter);

                        kobject_uevent_env(&dev->primary->kdev.kobj,
                                           KOBJ_CHANGE, reset_done_event);
                } else {
                        atomic_set(&error->reset_counter, I915_WEDGED);
                }

                /*
                 * Note: The wake_up also serves as a memory barrier so that
                 * waiters see the update value of the reset counter atomic_t.
                 */
                i915_error_wake_up(dev_priv, true);
        }
}

static void i915_report_and_clear_eir(struct drm_device *dev)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        uint32_t instdone[I915_NUM_INSTDONE_REG];
        u32 eir = I915_READ(EIR);
        int pipe, i;

        if (!eir)
                return;

        pr_err("render error detected, EIR: 0x%08x\n", eir);

        i915_get_extra_instdone(dev, instdone);

        if (IS_G4X(dev)) {
                if (eir & (GM45_ERROR_MEM_PRIV | GM45_ERROR_CP_PRIV)) {
                        u32 ipeir = I915_READ(IPEIR_I965);

                        pr_err("  IPEIR: 0x%08x\n", I915_READ(IPEIR_I965));
                        pr_err("  IPEHR: 0x%08x\n", I915_READ(IPEHR_I965));
                        for (i = 0; i < ARRAY_SIZE(instdone); i++)
                                pr_err("  INSTDONE_%d: 0x%08x\n", i, instdone[i]);
                        pr_err("  INSTPS: 0x%08x\n", I915_READ(INSTPS));
                        pr_err("  ACTHD: 0x%08x\n", I915_READ(ACTHD_I965));
                        I915_WRITE(IPEIR_I965, ipeir);
                        POSTING_READ(IPEIR_I965);
                }
                if (eir & GM45_ERROR_PAGE_TABLE) {
                        u32 pgtbl_err = I915_READ(PGTBL_ER);
                        pr_err("page table error\n");
                        pr_err("  PGTBL_ER: 0x%08x\n", pgtbl_err);
                        I915_WRITE(PGTBL_ER, pgtbl_err);
                        POSTING_READ(PGTBL_ER);
                }
        }

        if (!IS_GEN2(dev)) {
                if (eir & I915_ERROR_PAGE_TABLE) {
                        u32 pgtbl_err = I915_READ(PGTBL_ER);
                        pr_err("page table error\n");
                        pr_err("  PGTBL_ER: 0x%08x\n", pgtbl_err);
                        I915_WRITE(PGTBL_ER, pgtbl_err);
                        POSTING_READ(PGTBL_ER);
                }
        }

        if (eir & I915_ERROR_MEMORY_REFRESH) {
                pr_err("memory refresh error:\n");
                for_each_pipe(pipe)
                        pr_err("pipe %c stat: 0x%08x\n",
                               pipe_name(pipe), I915_READ(PIPESTAT(pipe)));
                /* pipestat has already been acked */
        }
        if (eir & I915_ERROR_INSTRUCTION) {
                pr_err("instruction error\n");
                pr_err("  INSTPM: 0x%08x\n", I915_READ(INSTPM));
                for (i = 0; i < ARRAY_SIZE(instdone); i++)
                        pr_err("  INSTDONE_%d: 0x%08x\n", i, instdone[i]);
                if (INTEL_INFO(dev)->gen < 4) {
                        u32 ipeir = I915_READ(IPEIR);

                        pr_err("  IPEIR: 0x%08x\n", I915_READ(IPEIR));
                        pr_err("  IPEHR: 0x%08x\n", I915_READ(IPEHR));
                        pr_err("  ACTHD: 0x%08x\n", I915_READ(ACTHD));
                        I915_WRITE(IPEIR, ipeir);
                        POSTING_READ(IPEIR);
                } else {
                        u32 ipeir = I915_READ(IPEIR_I965);

                        pr_err("  IPEIR: 0x%08x\n", I915_READ(IPEIR_I965));
                        pr_err("  IPEHR: 0x%08x\n", I915_READ(IPEHR_I965));
                        pr_err("  INSTPS: 0x%08x\n", I915_READ(INSTPS));
                        pr_err("  ACTHD: 0x%08x\n", I915_READ(ACTHD_I965));
                        I915_WRITE(IPEIR_I965, ipeir);
                        POSTING_READ(IPEIR_I965);
                }
        }

        I915_WRITE(EIR, eir);
        POSTING_READ(EIR);
        eir = I915_READ(EIR);
        if (eir) {
                /*
                 * some errors might have become stuck,
                 * mask them.
                 */
                DRM_ERROR("EIR stuck: 0x%08x, masking\n", eir);
                I915_WRITE(EMR, I915_READ(EMR) | eir);
                I915_WRITE(IIR, I915_RENDER_COMMAND_PARSER_ERROR_INTERRUPT);
        }
}

/**
 * i915_handle_error - handle an error interrupt
 * @dev: drm device
 *
 * Do some basic checking of regsiter state at error interrupt time and
 * dump it to the syslog.  Also call i915_capture_error_state() to make
 * sure we get a record and make it available in debugfs.  Fire a uevent
 * so userspace knows something bad happened (should trigger collection
 * of a ring dump etc.).
 */
void i915_handle_error(struct drm_device *dev, bool wedged)
{
        struct drm_i915_private *dev_priv = dev->dev_private;

        i915_capture_error_state(dev);
        i915_report_and_clear_eir(dev);

        if (wedged) {
                atomic_set_mask(I915_RESET_IN_PROGRESS_FLAG,
                                &dev_priv->gpu_error.reset_counter);

                /*
                 * Wakeup waiting processes so that the reset work function
                 * i915_error_work_func doesn't deadlock trying to grab various
                 * locks. By bumping the reset counter first, the woken
                 * processes will see a reset in progress and back off,
                 * releasing their locks and then wait for the reset completion.
                 * We must do this for _all_ gpu waiters that might hold locks
                 * that the reset work needs to acquire.
                 *
                 * Note: The wake_up serves as the required memory barrier to
                 * ensure that the waiters see the updated value of the reset
                 * counter atomic_t.
                 */
                i915_error_wake_up(dev_priv, false);
        }

        /*
         * Our reset work can grab modeset locks (since it needs to reset the
         * state of outstanding pagelips). Hence it must not be run on our own
         * dev-priv->wq work queue for otherwise the flush_work in the pageflip
         * code will deadlock.
         */
        schedule_work(&dev_priv->gpu_error.work);
}

static void __always_unused i915_pageflip_stall_check(struct drm_device *dev, int pipe)
{
        drm_i915_private_t *dev_priv = dev->dev_private;
        struct drm_crtc *crtc = dev_priv->pipe_to_crtc_mapping[pipe];
        struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
        struct drm_i915_gem_object *obj;
        struct intel_unpin_work *work;
        unsigned long flags;
        bool stall_detected;

        /* Ignore early vblank irqs */
        if (intel_crtc == NULL)
                return;

        spin_lock_irqsave(&dev->event_lock, flags);
        work = intel_crtc->unpin_work;

        if (work == NULL ||
            atomic_read(&work->pending) >= INTEL_FLIP_COMPLETE ||
            !work->enable_stall_check) {
                /* Either the pending flip IRQ arrived, or we're too early. Don't check */
                spin_unlock_irqrestore(&dev->event_lock, flags);
                return;
        }

        /* Potential stall - if we see that the flip has happened, assume a missed interrupt */
        obj = work->pending_flip_obj;
        if (INTEL_INFO(dev)->gen >= 4) {
                int dspsurf = DSPSURF(intel_crtc->plane);
                stall_detected = I915_HI_DISPBASE(I915_READ(dspsurf)) ==
                                        i915_gem_obj_ggtt_offset(obj);
        } else {
                int dspaddr = DSPADDR(intel_crtc->plane);
                stall_detected = I915_READ(dspaddr) == (i915_gem_obj_ggtt_offset(obj) +
                                                        crtc->y * crtc->fb->pitches[0] +
                                                        crtc->x * crtc->fb->bits_per_pixel/8);
        }

        spin_unlock_irqrestore(&dev->event_lock, flags);

        if (stall_detected) {
                DRM_DEBUG_DRIVER("Pageflip stall detected\n");
                intel_prepare_page_flip(dev, intel_crtc->plane);
        }
}

/* Called from drm generic code, passed 'crtc' which
 * we use as a pipe index
 */
static int i915_enable_vblank(struct drm_device *dev, int pipe)
{
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
        unsigned long irqflags;

        if (!i915_pipe_enabled(dev, pipe))
                return -EINVAL;

        spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
        if (INTEL_INFO(dev)->gen >= 4)
                i915_enable_pipestat(dev_priv, pipe,
                                     PIPE_START_VBLANK_INTERRUPT_ENABLE);
        else
                i915_enable_pipestat(dev_priv, pipe,
                                     PIPE_VBLANK_INTERRUPT_ENABLE);

        /* maintain vblank delivery even in deep C-states */
        if (dev_priv->info->gen == 3)
                I915_WRITE(INSTPM, _MASKED_BIT_DISABLE(INSTPM_AGPBUSY_DIS));
        spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);

        return 0;
}

static int ironlake_enable_vblank(struct drm_device *dev, int pipe)
{
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
        unsigned long irqflags;
        uint32_t bit = (INTEL_INFO(dev)->gen >= 7) ? DE_PIPE_VBLANK_IVB(pipe) :
                                                     DE_PIPE_VBLANK_ILK(pipe);

        if (!i915_pipe_enabled(dev, pipe))
                return -EINVAL;

        spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
        ironlake_enable_display_irq(dev_priv, bit);
        spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);

        return 0;
}

static int valleyview_enable_vblank(struct drm_device *dev, int pipe)
{
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
        unsigned long irqflags;
        u32 imr;

        if (!i915_pipe_enabled(dev, pipe))
                return -EINVAL;

        spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
        imr = I915_READ(VLV_IMR);
        if (pipe == 0)
                imr &= ~I915_DISPLAY_PIPE_A_VBLANK_INTERRUPT;
        else
                imr &= ~I915_DISPLAY_PIPE_B_VBLANK_INTERRUPT;
        I915_WRITE(VLV_IMR, imr);
        i915_enable_pipestat(dev_priv, pipe,
                             PIPE_START_VBLANK_INTERRUPT_ENABLE);
        spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);

        return 0;
}

/* Called from drm generic code, passed 'crtc' which
 * we use as a pipe index
 */
static void i915_disable_vblank(struct drm_device *dev, int pipe)
{
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
        unsigned long irqflags;

        spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
        if (dev_priv->info->gen == 3)
                I915_WRITE(INSTPM, _MASKED_BIT_ENABLE(INSTPM_AGPBUSY_DIS));

        i915_disable_pipestat(dev_priv, pipe,
                              PIPE_VBLANK_INTERRUPT_ENABLE |
                              PIPE_START_VBLANK_INTERRUPT_ENABLE);
        spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
}

static void ironlake_disable_vblank(struct drm_device *dev, int pipe)
{
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
        unsigned long irqflags;
        uint32_t bit = (INTEL_INFO(dev)->gen >= 7) ? DE_PIPE_VBLANK_IVB(pipe) :
                                                     DE_PIPE_VBLANK_ILK(pipe);

        spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
        ironlake_disable_display_irq(dev_priv, bit);
        spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
}

static void valleyview_disable_vblank(struct drm_device *dev, int pipe)
{
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
        unsigned long irqflags;
        u32 imr;

        spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
        i915_disable_pipestat(dev_priv, pipe,
                              PIPE_START_VBLANK_INTERRUPT_ENABLE);
        imr = I915_READ(VLV_IMR);
        if (pipe == 0)
                imr |= I915_DISPLAY_PIPE_A_VBLANK_INTERRUPT;
        else
                imr |= I915_DISPLAY_PIPE_B_VBLANK_INTERRUPT;
        I915_WRITE(VLV_IMR, imr);
        spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
}

static u32
ring_last_seqno(struct intel_ring_buffer *ring)
{
        return list_entry(ring->request_list.prev,
                          struct drm_i915_gem_request, list)->seqno;
}

static bool
ring_idle(struct intel_ring_buffer *ring, u32 seqno)
{
        return (list_empty(&ring->request_list) ||
                i915_seqno_passed(seqno, ring_last_seqno(ring)));
}

static struct intel_ring_buffer *
semaphore_waits_for(struct intel_ring_buffer *ring, u32 *seqno)
{
        struct drm_i915_private *dev_priv = ring->dev->dev_private;
        u32 cmd, ipehr, acthd, acthd_min;

        ipehr = I915_READ(RING_IPEHR(ring->mmio_base));
        if ((ipehr & ~(0x3 << 16)) !=
            (MI_SEMAPHORE_MBOX | MI_SEMAPHORE_COMPARE | MI_SEMAPHORE_REGISTER))
                return NULL;

        /* ACTHD is likely pointing to the dword after the actual command,
         * so scan backwards until we find the MBOX.
         */
        acthd = intel_ring_get_active_head(ring) & HEAD_ADDR;
        acthd_min = max((int)acthd - 3 * 4, 0);
        do {
                cmd = ioread32(ring->virtual_start + acthd);
                if (cmd == ipehr)
                        break;

                acthd -= 4;
                if (acthd < acthd_min)
                        return NULL;
        } while (1);

        *seqno = ioread32(ring->virtual_start+acthd+4)+1;
        return &dev_priv->ring[(ring->id + (((ipehr >> 17) & 1) + 1)) % 3];
}

static int semaphore_passed(struct intel_ring_buffer *ring)
{
        struct drm_i915_private *dev_priv = ring->dev->dev_private;
        struct intel_ring_buffer *signaller;
        u32 seqno, ctl;

        ring->hangcheck.deadlock = true;

        signaller = semaphore_waits_for(ring, &seqno);
        if (signaller == NULL || signaller->hangcheck.deadlock)
                return -1;

        /* cursory check for an unkickable deadlock */
        ctl = I915_READ_CTL(signaller);
        if (ctl & RING_WAIT_SEMAPHORE && semaphore_passed(signaller) < 0)
                return -1;

        return i915_seqno_passed(signaller->get_seqno(signaller, false), seqno);
}

static void semaphore_clear_deadlocks(struct drm_i915_private *dev_priv)
{
        struct intel_ring_buffer *ring;
        int i;

        for_each_ring(ring, dev_priv, i)
                ring->hangcheck.deadlock = false;
}

static enum intel_ring_hangcheck_action
ring_stuck(struct intel_ring_buffer *ring, u32 acthd)
{
        struct drm_device *dev = ring->dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        u32 tmp;

        if (ring->hangcheck.acthd != acthd)
                return HANGCHECK_ACTIVE;

        if (IS_GEN2(dev))
                return HANGCHECK_HUNG;

        /* Is the chip hanging on a WAIT_FOR_EVENT?
         * If so we can simply poke the RB_WAIT bit
         * and break the hang. This should work on
         * all but the second generation chipsets.
         */
        tmp = I915_READ_CTL(ring);
        if (tmp & RING_WAIT) {
                DRM_ERROR("Kicking stuck wait on %s\n",
                          ring->name);
                I915_WRITE_CTL(ring, tmp);
                return HANGCHECK_KICK;
        }

        if (INTEL_INFO(dev)->gen >= 6 && tmp & RING_WAIT_SEMAPHORE) {
                switch (semaphore_passed(ring)) {
                default:
                        return HANGCHECK_HUNG;
                case 1:
                        DRM_ERROR("Kicking stuck semaphore on %s\n",
                                  ring->name);
                        I915_WRITE_CTL(ring, tmp);
                        return HANGCHECK_KICK;
                case 0:
                        return HANGCHECK_WAIT;
                }
        }

        return HANGCHECK_HUNG;
}

/**
 * This is called when the chip hasn't reported back with completed
 * batchbuffers in a long time. We keep track per ring seqno progress and
 * if there are no progress, hangcheck score for that ring is increased.
 * Further, acthd is inspected to see if the ring is stuck. On stuck case
 * we kick the ring. If we see no progress on three subsequent calls
 * we assume chip is wedged and try to fix it by resetting the chip.
 */
static void i915_hangcheck_elapsed(unsigned long data)
{
        struct drm_device *dev = (struct drm_device *)data;
        drm_i915_private_t *dev_priv = dev->dev_private;

        struct intel_ring_buffer *ring;
        int i;
        int busy_count = 0, rings_hung = 0;
        bool stuck[I915_NUM_RINGS] = { 0 };
#define BUSY 1
#define KICK 5
#define HUNG 20
#define FIRE 30

        if (!i915_enable_hangcheck)
                return;

        for_each_ring(ring, dev_priv, i) {
                u32 seqno, acthd;
                bool busy = true;

                semaphore_clear_deadlocks(dev_priv);

                seqno = ring->get_seqno(ring, false);
                acthd = intel_ring_get_active_head(ring);

                if (ring->hangcheck.seqno == seqno) {
                        if (ring_idle(ring, seqno)) {
                                if (waitqueue_active(&ring->irq_queue)) {
                                        /* Issue a wake-up to catch stuck h/w. */
                                        DRM_ERROR("Hangcheck timer elapsed... %s idle\n",
                                                  ring->name);
                                        wake_up_all(&ring->irq_queue);
                                        ring->hangcheck.score += HUNG;
                                } else
                                        busy = false;
                        } else {
                                /* We always increment the hangcheck score
                                 * if the ring is busy and still processing
                                 * the same request, so that no single request
                                 * can run indefinitely (such as a chain of
                                 * batches). The only time we do not increment
                                 * the hangcheck score on this ring, if this
                                 * ring is in a legitimate wait for another
                                 * ring. In that case the waiting ring is a
                                 * victim and we want to be sure we catch the
                                 * right culprit. Then every time we do kick
                                 * the ring, add a small increment to the
                                 * score so that we can catch a batch that is
                                 * being repeatedly kicked and so responsible
                                 * for stalling the machine.
                                 */
                                ring->hangcheck.action = ring_stuck(ring,
                                                                    acthd);

                                switch (ring->hangcheck.action) {
                                case HANGCHECK_WAIT:
                                        break;
                                case HANGCHECK_ACTIVE:
                                        ring->hangcheck.score += BUSY;
                                        break;
                                case HANGCHECK_KICK:
                                        ring->hangcheck.score += KICK;
                                        break;
                                case HANGCHECK_HUNG:
                                        ring->hangcheck.score += HUNG;
                                        stuck[i] = true;
                                        break;
                                }
                        }
                } else {
                        /* Gradually reduce the count so that we catch DoS
                         * attempts across multiple batches.
                         */
                        if (ring->hangcheck.score > 0)
                                ring->hangcheck.score--;
                }

                ring->hangcheck.seqno = seqno;
                ring->hangcheck.acthd = acthd;
                busy_count += busy;
        }

        for_each_ring(ring, dev_priv, i) {
                if (ring->hangcheck.score > FIRE) {
                        DRM_INFO("%s on %s\n",
                                 stuck[i] ? "stuck" : "no progress",
                                 ring->name);
                        rings_hung++;
                }
        }

        if (rings_hung)
                return i915_handle_error(dev, true);

        if (busy_count)
                /* Reset timer case chip hangs without another request
                 * being added */
                i915_queue_hangcheck(dev);
}

void i915_queue_hangcheck(struct drm_device *dev)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        if (!i915_enable_hangcheck)
                return;

        mod_timer(&dev_priv->gpu_error.hangcheck_timer,
                  round_jiffies_up(jiffies + DRM_I915_HANGCHECK_JIFFIES));
}

static void ibx_irq_preinstall(struct drm_device *dev)
{
        struct drm_i915_private *dev_priv = dev->dev_private;

        if (HAS_PCH_NOP(dev))
                return;

        /* south display irq */
        I915_WRITE(SDEIMR, 0xffffffff);
        /*
         * SDEIER is also touched by the interrupt handler to work around missed
         * PCH interrupts. Hence we can't update it after the interrupt handler
         * is enabled - instead we unconditionally enable all PCH interrupt
         * sources here, but then only unmask them as needed with SDEIMR.
         */
        I915_WRITE(SDEIER, 0xffffffff);
        POSTING_READ(SDEIER);
}

static void gen5_gt_irq_preinstall(struct drm_device *dev)
{
        struct drm_i915_private *dev_priv = dev->dev_private;

        /* and GT */
        I915_WRITE(GTIMR, 0xffffffff);
        I915_WRITE(GTIER, 0x0);
        POSTING_READ(GTIER);

        if (INTEL_INFO(dev)->gen >= 6) {
                /* and PM */
                I915_WRITE(GEN6_PMIMR, 0xffffffff);
                I915_WRITE(GEN6_PMIER, 0x0);
                POSTING_READ(GEN6_PMIER);
        }
}

/* drm_dma.h hooks
*/
static void ironlake_irq_preinstall(struct drm_device *dev)
{
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;

        atomic_set(&dev_priv->irq_received, 0);

        I915_WRITE(HWSTAM, 0xeffe);

        I915_WRITE(DEIMR, 0xffffffff);
        I915_WRITE(DEIER, 0x0);
        POSTING_READ(DEIER);

        gen5_gt_irq_preinstall(dev);

        ibx_irq_preinstall(dev);
}

static void valleyview_irq_preinstall(struct drm_device *dev)
{
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
        int pipe;

        atomic_set(&dev_priv->irq_received, 0);

        /* VLV magic */
        I915_WRITE(VLV_IMR, 0);
        I915_WRITE(RING_IMR(RENDER_RING_BASE), 0);
        I915_WRITE(RING_IMR(GEN6_BSD_RING_BASE), 0);
        I915_WRITE(RING_IMR(BLT_RING_BASE), 0);

        /* and GT */
        I915_WRITE(GTIIR, I915_READ(GTIIR));
        I915_WRITE(GTIIR, I915_READ(GTIIR));

        gen5_gt_irq_preinstall(dev);

        I915_WRITE(DPINVGTT, 0xff);

        I915_WRITE(PORT_HOTPLUG_EN, 0);
        I915_WRITE(PORT_HOTPLUG_STAT, I915_READ(PORT_HOTPLUG_STAT));
        for_each_pipe(pipe)
                I915_WRITE(PIPESTAT(pipe), 0xffff);
        I915_WRITE(VLV_IIR, 0xffffffff);
        I915_WRITE(VLV_IMR, 0xffffffff);
        I915_WRITE(VLV_IER, 0x0);
        POSTING_READ(VLV_IER);
}

static void ibx_hpd_irq_setup(struct drm_device *dev)
{
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
        struct drm_mode_config *mode_config = &dev->mode_config;
        struct intel_encoder *intel_encoder;
        u32 hotplug_irqs, hotplug, enabled_irqs = 0;

        if (HAS_PCH_IBX(dev)) {
                hotplug_irqs = SDE_HOTPLUG_MASK;
                list_for_each_entry(intel_encoder, &mode_config->encoder_list, base.head)
                        if (dev_priv->hpd_stats[intel_encoder->hpd_pin].hpd_mark == HPD_ENABLED)
                                enabled_irqs |= hpd_ibx[intel_encoder->hpd_pin];
        } else {
                hotplug_irqs = SDE_HOTPLUG_MASK_CPT;
                list_for_each_entry(intel_encoder, &mode_config->encoder_list, base.head)
                        if (dev_priv->hpd_stats[intel_encoder->hpd_pin].hpd_mark == HPD_ENABLED)
                                enabled_irqs |= hpd_cpt[intel_encoder->hpd_pin];
        }

        ibx_display_interrupt_update(dev_priv, hotplug_irqs, enabled_irqs);

        /*
         * Enable digital hotplug on the PCH, and configure the DP short pulse
         * duration to 2ms (which is the minimum in the Display Port spec)
         *
         * This register is the same on all known PCH chips.
         */
        hotplug = I915_READ(PCH_PORT_HOTPLUG);
        hotplug &= ~(PORTD_PULSE_DURATION_MASK|PORTC_PULSE_DURATION_MASK|PORTB_PULSE_DURATION_MASK);
        hotplug |= PORTD_HOTPLUG_ENABLE | PORTD_PULSE_DURATION_2ms;
        hotplug |= PORTC_HOTPLUG_ENABLE | PORTC_PULSE_DURATION_2ms;
        hotplug |= PORTB_HOTPLUG_ENABLE | PORTB_PULSE_DURATION_2ms;
        I915_WRITE(PCH_PORT_HOTPLUG, hotplug);
}

static void ibx_irq_postinstall(struct drm_device *dev)
{
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
        u32 mask;

        if (HAS_PCH_NOP(dev))
                return;

        if (HAS_PCH_IBX(dev)) {
                mask = SDE_GMBUS | SDE_AUX_MASK | SDE_TRANSB_FIFO_UNDER |
                       SDE_TRANSA_FIFO_UNDER | SDE_POISON;
        } else {
                mask = SDE_GMBUS_CPT | SDE_AUX_MASK_CPT | SDE_ERROR_CPT;

                I915_WRITE(SERR_INT, I915_READ(SERR_INT));
        }

        I915_WRITE(SDEIIR, I915_READ(SDEIIR));
        I915_WRITE(SDEIMR, ~mask);
}

static void gen5_gt_irq_postinstall(struct drm_device *dev)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        u32 pm_irqs, gt_irqs;

        pm_irqs = gt_irqs = 0;

        dev_priv->gt_irq_mask = ~0;
        if (HAS_L3_GPU_CACHE(dev)) {
                /* L3 parity interrupt is always unmasked. */
                dev_priv->gt_irq_mask = ~GT_RENDER_L3_PARITY_ERROR_INTERRUPT;
                gt_irqs |= GT_RENDER_L3_PARITY_ERROR_INTERRUPT;
        }

        gt_irqs |= GT_RENDER_USER_INTERRUPT;
        if (IS_GEN5(dev)) {
                gt_irqs |= GT_RENDER_PIPECTL_NOTIFY_INTERRUPT |
                           ILK_BSD_USER_INTERRUPT;
        } else {
                gt_irqs |= GT_BLT_USER_INTERRUPT | GT_BSD_USER_INTERRUPT;
        }

        I915_WRITE(GTIIR, I915_READ(GTIIR));
        I915_WRITE(GTIMR, dev_priv->gt_irq_mask);
        I915_WRITE(GTIER, gt_irqs);
        POSTING_READ(GTIER);

        if (INTEL_INFO(dev)->gen >= 6) {
                pm_irqs |= GEN6_PM_RPS_EVENTS;

                if (HAS_VEBOX(dev))
                        pm_irqs |= PM_VEBOX_USER_INTERRUPT;

                dev_priv->pm_irq_mask = 0xffffffff;
                I915_WRITE(GEN6_PMIIR, I915_READ(GEN6_PMIIR));
                I915_WRITE(GEN6_PMIMR, dev_priv->pm_irq_mask);
                I915_WRITE(GEN6_PMIER, pm_irqs);
                POSTING_READ(GEN6_PMIER);
        }
}

static int ironlake_irq_postinstall(struct drm_device *dev)
{
        unsigned long irqflags;
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
        u32 display_mask, extra_mask;

        if (INTEL_INFO(dev)->gen >= 7) {
                display_mask = (DE_MASTER_IRQ_CONTROL | DE_GSE_IVB |
                                DE_PCH_EVENT_IVB | DE_PLANEC_FLIP_DONE_IVB |
                                DE_PLANEB_FLIP_DONE_IVB |
                                DE_PLANEA_FLIP_DONE_IVB | DE_AUX_CHANNEL_A_IVB |
                                DE_ERR_INT_IVB);
                extra_mask = (DE_PIPEC_VBLANK_IVB | DE_PIPEB_VBLANK_IVB |
                              DE_PIPEA_VBLANK_IVB);

                I915_WRITE(GEN7_ERR_INT, I915_READ(GEN7_ERR_INT));
        } else {
                display_mask = (DE_MASTER_IRQ_CONTROL | DE_GSE | DE_PCH_EVENT |
                                DE_PLANEA_FLIP_DONE | DE_PLANEB_FLIP_DONE |
                                DE_AUX_CHANNEL_A | DE_PIPEB_FIFO_UNDERRUN |
                                DE_PIPEA_FIFO_UNDERRUN | DE_POISON);
                extra_mask = DE_PIPEA_VBLANK | DE_PIPEB_VBLANK | DE_PCU_EVENT;
        }

        dev_priv->irq_mask = ~display_mask;

        /* should always can generate irq */
        I915_WRITE(DEIIR, I915_READ(DEIIR));
        I915_WRITE(DEIMR, dev_priv->irq_mask);
        I915_WRITE(DEIER, display_mask | extra_mask);
        POSTING_READ(DEIER);

        gen5_gt_irq_postinstall(dev);

        ibx_irq_postinstall(dev);

        if (IS_IRONLAKE_M(dev)) {
                /* Enable PCU event interrupts
                 *
                 * spinlocking not required here for correctness since interrupt
                 * setup is guaranteed to run in single-threaded context. But we
                 * need it to make the assert_spin_locked happy. */
                spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
                ironlake_enable_display_irq(dev_priv, DE_PCU_EVENT);
                spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
        }

        return 0;
}

static int valleyview_irq_postinstall(struct drm_device *dev)
{
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
        u32 enable_mask;
        u32 pipestat_enable = PLANE_FLIP_DONE_INT_EN_VLV;
        unsigned long irqflags;

        enable_mask = I915_DISPLAY_PORT_INTERRUPT;
        enable_mask |= I915_DISPLAY_PIPE_A_EVENT_INTERRUPT |
                I915_DISPLAY_PIPE_A_VBLANK_INTERRUPT |
                I915_DISPLAY_PIPE_B_EVENT_INTERRUPT |
                I915_DISPLAY_PIPE_B_VBLANK_INTERRUPT;

        /*
         *Leave vblank interrupts masked initially.  enable/disable will
         * toggle them based on usage.
         */
        dev_priv->irq_mask = (~enable_mask) |
                I915_DISPLAY_PIPE_A_VBLANK_INTERRUPT |
                I915_DISPLAY_PIPE_B_VBLANK_INTERRUPT;

        I915_WRITE(PORT_HOTPLUG_EN, 0);
        POSTING_READ(PORT_HOTPLUG_EN);

        I915_WRITE(VLV_IMR, dev_priv->irq_mask);
        I915_WRITE(VLV_IER, enable_mask);
        I915_WRITE(VLV_IIR, 0xffffffff);
        I915_WRITE(PIPESTAT(0), 0xffff);
        I915_WRITE(PIPESTAT(1), 0xffff);
        POSTING_READ(VLV_IER);

        /* Interrupt setup is already guaranteed to be single-threaded, this is
         * just to make the assert_spin_locked check happy. */
        spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
        i915_enable_pipestat(dev_priv, 0, pipestat_enable);
        i915_enable_pipestat(dev_priv, 0, PIPE_GMBUS_EVENT_ENABLE);
        i915_enable_pipestat(dev_priv, 1, pipestat_enable);
        spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);

        I915_WRITE(VLV_IIR, 0xffffffff);
        I915_WRITE(VLV_IIR, 0xffffffff);

        gen5_gt_irq_postinstall(dev);

        /* ack & enable invalid PTE error interrupts */
#if 0 /* FIXME: add support to irq handler for checking these bits */
        I915_WRITE(DPINVGTT, DPINVGTT_STATUS_MASK);
        I915_WRITE(DPINVGTT, DPINVGTT_EN_MASK);
#endif

        I915_WRITE(VLV_MASTER_IER, MASTER_INTERRUPT_ENABLE);

        return 0;
}

static void valleyview_irq_uninstall(struct drm_device *dev)
{
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
        int pipe;

        if (!dev_priv)
                return;

        del_timer_sync(&dev_priv->hotplug_reenable_timer);

        for_each_pipe(pipe)
                I915_WRITE(PIPESTAT(pipe), 0xffff);

        I915_WRITE(HWSTAM, 0xffffffff);
        I915_WRITE(PORT_HOTPLUG_EN, 0);
        I915_WRITE(PORT_HOTPLUG_STAT, I915_READ(PORT_HOTPLUG_STAT));
        for_each_pipe(pipe)
                I915_WRITE(PIPESTAT(pipe), 0xffff);
        I915_WRITE(VLV_IIR, 0xffffffff);
        I915_WRITE(VLV_IMR, 0xffffffff);
        I915_WRITE(VLV_IER, 0x0);
        POSTING_READ(VLV_IER);
}

static void ironlake_irq_uninstall(struct drm_device *dev)
{
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;

        if (!dev_priv)
                return;

        del_timer_sync(&dev_priv->hotplug_reenable_timer);

        I915_WRITE(HWSTAM, 0xffffffff);

        I915_WRITE(DEIMR, 0xffffffff);
        I915_WRITE(DEIER, 0x0);
        I915_WRITE(DEIIR, I915_READ(DEIIR));
        if (IS_GEN7(dev))
                I915_WRITE(GEN7_ERR_INT, I915_READ(GEN7_ERR_INT));

        I915_WRITE(GTIMR, 0xffffffff);
        I915_WRITE(GTIER, 0x0);
        I915_WRITE(GTIIR, I915_READ(GTIIR));

        if (HAS_PCH_NOP(dev))
                return;

        I915_WRITE(SDEIMR, 0xffffffff);
        I915_WRITE(SDEIER, 0x0);
        I915_WRITE(SDEIIR, I915_READ(SDEIIR));
        if (HAS_PCH_CPT(dev) || HAS_PCH_LPT(dev))
                I915_WRITE(SERR_INT, I915_READ(SERR_INT));
}

static void i8xx_irq_preinstall(struct drm_device * dev)
{
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
        int pipe;

        atomic_set(&dev_priv->irq_received, 0);

        for_each_pipe(pipe)
                I915_WRITE(PIPESTAT(pipe), 0);
        I915_WRITE16(IMR, 0xffff);
        I915_WRITE16(IER, 0x0);
        POSTING_READ16(IER);
}

static int i8xx_irq_postinstall(struct drm_device *dev)
{
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;

        I915_WRITE16(EMR,
                     ~(I915_ERROR_PAGE_TABLE | I915_ERROR_MEMORY_REFRESH));

        /* Unmask the interrupts that we always want on. */
        dev_priv->irq_mask =
                ~(I915_DISPLAY_PIPE_A_EVENT_INTERRUPT |
                  I915_DISPLAY_PIPE_B_EVENT_INTERRUPT |
                  I915_DISPLAY_PLANE_A_FLIP_PENDING_INTERRUPT |
                  I915_DISPLAY_PLANE_B_FLIP_PENDING_INTERRUPT |
                  I915_RENDER_COMMAND_PARSER_ERROR_INTERRUPT);
        I915_WRITE16(IMR, dev_priv->irq_mask);

        I915_WRITE16(IER,
                     I915_DISPLAY_PIPE_A_EVENT_INTERRUPT |
                     I915_DISPLAY_PIPE_B_EVENT_INTERRUPT |
                     I915_RENDER_COMMAND_PARSER_ERROR_INTERRUPT |
                     I915_USER_INTERRUPT);
        POSTING_READ16(IER);

        return 0;
}

/*
 * Returns true when a page flip has completed.
 */
static bool i8xx_handle_vblank(struct drm_device *dev,
                               int pipe, u16 iir)
{
        drm_i915_private_t *dev_priv = dev->dev_private;
        u16 flip_pending = DISPLAY_PLANE_FLIP_PENDING(pipe);

        if (!drm_handle_vblank(dev, pipe))
                return false;

        if ((iir & flip_pending) == 0)
                return false;

        intel_prepare_page_flip(dev, pipe);

        /* We detect FlipDone by looking for the change in PendingFlip from '1'
         * to '0' on the following vblank, i.e. IIR has the Pendingflip
         * asserted following the MI_DISPLAY_FLIP, but ISR is deasserted, hence
         * the flip is completed (no longer pending). Since this doesn't raise
         * an interrupt per se, we watch for the change at vblank.
         */
        if (I915_READ16(ISR) & flip_pending)
                return false;

        intel_finish_page_flip(dev, pipe);

        return true;
}

static irqreturn_t i8xx_irq_handler(int irq, void *arg)
{
        struct drm_device *dev = (struct drm_device *) arg;
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
        u16 iir, new_iir;
        u32 pipe_stats[2];
        unsigned long irqflags;
        int pipe;
        u16 flip_mask =
                I915_DISPLAY_PLANE_A_FLIP_PENDING_INTERRUPT |
                I915_DISPLAY_PLANE_B_FLIP_PENDING_INTERRUPT;

        atomic_inc(&dev_priv->irq_received);

        iir = I915_READ16(IIR);
        if (iir == 0)
                return IRQ_NONE;

        while (iir & ~flip_mask) {
                /* Can't rely on pipestat interrupt bit in iir as it might
                 * have been cleared after the pipestat interrupt was received.
                 * It doesn't set the bit in iir again, but it still produces
                 * interrupts (for non-MSI).
                 */
                spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
                if (iir & I915_RENDER_COMMAND_PARSER_ERROR_INTERRUPT)
                        i915_handle_error(dev, false);

                for_each_pipe(pipe) {
                        int reg = PIPESTAT(pipe);
                        pipe_stats[pipe] = I915_READ(reg);

                        /*
                         * Clear the PIPE*STAT regs before the IIR
                         */
                        if (pipe_stats[pipe] & 0x8000ffff) {
                                if (pipe_stats[pipe] & PIPE_FIFO_UNDERRUN_STATUS)
                                        DRM_DEBUG_DRIVER("pipe %c underrun\n",
                                                         pipe_name(pipe));
                                I915_WRITE(reg, pipe_stats[pipe]);
                        }
                }
                spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);

                I915_WRITE16(IIR, iir & ~flip_mask);
                new_iir = I915_READ16(IIR); /* Flush posted writes */

                i915_update_dri1_breadcrumb(dev);

                if (iir & I915_USER_INTERRUPT)
                        notify_ring(dev, &dev_priv->ring[RCS]);

                if (pipe_stats[0] & PIPE_VBLANK_INTERRUPT_STATUS &&
                    i8xx_handle_vblank(dev, 0, iir))
                        flip_mask &= ~DISPLAY_PLANE_FLIP_PENDING(0);

                if (pipe_stats[1] & PIPE_VBLANK_INTERRUPT_STATUS &&
                    i8xx_handle_vblank(dev, 1, iir))
                        flip_mask &= ~DISPLAY_PLANE_FLIP_PENDING(1);

                iir = new_iir;
        }

        return IRQ_HANDLED;
}

static void i8xx_irq_uninstall(struct drm_device * dev)
{
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
        int pipe;

        for_each_pipe(pipe) {
                /* Clear enable bits; then clear status bits */
                I915_WRITE(PIPESTAT(pipe), 0);
                I915_WRITE(PIPESTAT(pipe), I915_READ(PIPESTAT(pipe)));
        }
        I915_WRITE16(IMR, 0xffff);
        I915_WRITE16(IER, 0x0);
        I915_WRITE16(IIR, I915_READ16(IIR));
}

static void i915_irq_preinstall(struct drm_device * dev)
{
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
        int pipe;

        atomic_set(&dev_priv->irq_received, 0);

        if (I915_HAS_HOTPLUG(dev)) {
                I915_WRITE(PORT_HOTPLUG_EN, 0);
                I915_WRITE(PORT_HOTPLUG_STAT, I915_READ(PORT_HOTPLUG_STAT));
        }

        I915_WRITE16(HWSTAM, 0xeffe);
        for_each_pipe(pipe)
                I915_WRITE(PIPESTAT(pipe), 0);
        I915_WRITE(IMR, 0xffffffff);
        I915_WRITE(IER, 0x0);
        POSTING_READ(IER);
}

static int i915_irq_postinstall(struct drm_device *dev)
{
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
        u32 enable_mask;

        I915_WRITE(EMR, ~(I915_ERROR_PAGE_TABLE | I915_ERROR_MEMORY_REFRESH));

        /* Unmask the interrupts that we always want on. */
        dev_priv->irq_mask =
                ~(I915_ASLE_INTERRUPT |
                  I915_DISPLAY_PIPE_A_EVENT_INTERRUPT |
                  I915_DISPLAY_PIPE_B_EVENT_INTERRUPT |
                  I915_DISPLAY_PLANE_A_FLIP_PENDING_INTERRUPT |
                  I915_DISPLAY_PLANE_B_FLIP_PENDING_INTERRUPT |
                  I915_RENDER_COMMAND_PARSER_ERROR_INTERRUPT);

        enable_mask =
                I915_ASLE_INTERRUPT |
                I915_DISPLAY_PIPE_A_EVENT_INTERRUPT |
                I915_DISPLAY_PIPE_B_EVENT_INTERRUPT |
                I915_RENDER_COMMAND_PARSER_ERROR_INTERRUPT |
                I915_USER_INTERRUPT;

        if (I915_HAS_HOTPLUG(dev)) {
                I915_WRITE(PORT_HOTPLUG_EN, 0);
                POSTING_READ(PORT_HOTPLUG_EN);

                /* Enable in IER... */
                enable_mask |= I915_DISPLAY_PORT_INTERRUPT;
                /* and unmask in IMR */
                dev_priv->irq_mask &= ~I915_DISPLAY_PORT_INTERRUPT;
        }

        I915_WRITE(IMR, dev_priv->irq_mask);
        I915_WRITE(IER, enable_mask);
        POSTING_READ(IER);

        i915_enable_asle_pipestat(dev);

        return 0;
}

/*
 * Returns true when a page flip has completed.
 */
static bool i915_handle_vblank(struct drm_device *dev,
                               int plane, int pipe, u32 iir)
{
        drm_i915_private_t *dev_priv = dev->dev_private;
        u32 flip_pending = DISPLAY_PLANE_FLIP_PENDING(plane);

        if (!drm_handle_vblank(dev, pipe))
                return false;

        if ((iir & flip_pending) == 0)
                return false;

        intel_prepare_page_flip(dev, plane);

        /* We detect FlipDone by looking for the change in PendingFlip from '1'
         * to '0' on the following vblank, i.e. IIR has the Pendingflip
         * asserted following the MI_DISPLAY_FLIP, but ISR is deasserted, hence
         * the flip is completed (no longer pending). Since this doesn't raise
         * an interrupt per se, we watch for the change at vblank.
         */
        if (I915_READ(ISR) & flip_pending)
                return false;

        intel_finish_page_flip(dev, pipe);

        return true;
}

static irqreturn_t i915_irq_handler(int irq, void *arg)
{
        struct drm_device *dev = (struct drm_device *) arg;
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
        u32 iir, new_iir, pipe_stats[I915_MAX_PIPES];
        unsigned long irqflags;
        u32 flip_mask =
                I915_DISPLAY_PLANE_A_FLIP_PENDING_INTERRUPT |
                I915_DISPLAY_PLANE_B_FLIP_PENDING_INTERRUPT;
        int pipe, ret = IRQ_NONE;

        atomic_inc(&dev_priv->irq_received);

        iir = I915_READ(IIR);
        do {
                bool irq_received = (iir & ~flip_mask) != 0;
                bool blc_event = false;

                /* Can't rely on pipestat interrupt bit in iir as it might
                 * have been cleared after the pipestat interrupt was received.
                 * It doesn't set the bit in iir again, but it still produces
                 * interrupts (for non-MSI).
                 */
                spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
                if (iir & I915_RENDER_COMMAND_PARSER_ERROR_INTERRUPT)
                        i915_handle_error(dev, false);

                for_each_pipe(pipe) {
                        int reg = PIPESTAT(pipe);
                        pipe_stats[pipe] = I915_READ(reg);

                        /* Clear the PIPE*STAT regs before the IIR */
                        if (pipe_stats[pipe] & 0x8000ffff) {
                                if (pipe_stats[pipe] & PIPE_FIFO_UNDERRUN_STATUS)
                                        DRM_DEBUG_DRIVER("pipe %c underrun\n",
                                                         pipe_name(pipe));
                                I915_WRITE(reg, pipe_stats[pipe]);
                                irq_received = true;
                        }
                }
                spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);

                if (!irq_received)
                        break;

                /* Consume port.  Then clear IIR or we'll miss events */
                if ((I915_HAS_HOTPLUG(dev)) &&
                    (iir & I915_DISPLAY_PORT_INTERRUPT)) {
                        u32 hotplug_status = I915_READ(PORT_HOTPLUG_STAT);
                        u32 hotplug_trigger = hotplug_status & HOTPLUG_INT_STATUS_I915;

                        DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
                                  hotplug_status);

                        intel_hpd_irq_handler(dev, hotplug_trigger, hpd_status_i915);

                        I915_WRITE(PORT_HOTPLUG_STAT, hotplug_status);
                        POSTING_READ(PORT_HOTPLUG_STAT);
                }

                I915_WRITE(IIR, iir & ~flip_mask);
                new_iir = I915_READ(IIR); /* Flush posted writes */

                if (iir & I915_USER_INTERRUPT)
                        notify_ring(dev, &dev_priv->ring[RCS]);

                for_each_pipe(pipe) {
                        int plane = pipe;
                        if (IS_MOBILE(dev))
                                plane = !plane;

                        if (pipe_stats[pipe] & PIPE_VBLANK_INTERRUPT_STATUS &&
                            i915_handle_vblank(dev, plane, pipe, iir))
                                flip_mask &= ~DISPLAY_PLANE_FLIP_PENDING(plane);

                        if (pipe_stats[pipe] & PIPE_LEGACY_BLC_EVENT_STATUS)
                                blc_event = true;
                }

                if (blc_event || (iir & I915_ASLE_INTERRUPT))
                        intel_opregion_asle_intr(dev);

                /* With MSI, interrupts are only generated when iir
                 * transitions from zero to nonzero.  If another bit got
                 * set while we were handling the existing iir bits, then
                 * we would never get another interrupt.
                 *
                 * This is fine on non-MSI as well, as if we hit this path
                 * we avoid exiting the interrupt handler only to generate
                 * another one.
                 *
                 * Note that for MSI this could cause a stray interrupt report
                 * if an interrupt landed in the time between writing IIR and
                 * the posting read.  This should be rare enough to never
                 * trigger the 99% of 100,000 interrupts test for disabling
                 * stray interrupts.
                 */
                ret = IRQ_HANDLED;
                iir = new_iir;
        } while (iir & ~flip_mask);

        i915_update_dri1_breadcrumb(dev);

        return ret;
}

static void i915_irq_uninstall(struct drm_device * dev)
{
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
        int pipe;

        del_timer_sync(&dev_priv->hotplug_reenable_timer);

        if (I915_HAS_HOTPLUG(dev)) {
                I915_WRITE(PORT_HOTPLUG_EN, 0);
                I915_WRITE(PORT_HOTPLUG_STAT, I915_READ(PORT_HOTPLUG_STAT));
        }

        I915_WRITE16(HWSTAM, 0xffff);
        for_each_pipe(pipe) {
                /* Clear enable bits; then clear status bits */
                I915_WRITE(PIPESTAT(pipe), 0);
                I915_WRITE(PIPESTAT(pipe), I915_READ(PIPESTAT(pipe)));
        }
        I915_WRITE(IMR, 0xffffffff);
        I915_WRITE(IER, 0x0);

        I915_WRITE(IIR, I915_READ(IIR));
}

static void i965_irq_preinstall(struct drm_device * dev)
{
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
        int pipe;

        atomic_set(&dev_priv->irq_received, 0);

        I915_WRITE(PORT_HOTPLUG_EN, 0);
        I915_WRITE(PORT_HOTPLUG_STAT, I915_READ(PORT_HOTPLUG_STAT));

        I915_WRITE(HWSTAM, 0xeffe);
        for_each_pipe(pipe)
                I915_WRITE(PIPESTAT(pipe), 0);
        I915_WRITE(IMR, 0xffffffff);
        I915_WRITE(IER, 0x0);
        POSTING_READ(IER);
}

static int i965_irq_postinstall(struct drm_device *dev)
{
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
        u32 enable_mask;
        u32 error_mask;
        unsigned long irqflags;

        /* Unmask the interrupts that we always want on. */
        dev_priv->irq_mask = ~(I915_ASLE_INTERRUPT |
                               I915_DISPLAY_PORT_INTERRUPT |
                               I915_DISPLAY_PIPE_A_EVENT_INTERRUPT |
                               I915_DISPLAY_PIPE_B_EVENT_INTERRUPT |
                               I915_DISPLAY_PLANE_A_FLIP_PENDING_INTERRUPT |
                               I915_DISPLAY_PLANE_B_FLIP_PENDING_INTERRUPT |
                               I915_RENDER_COMMAND_PARSER_ERROR_INTERRUPT);

        enable_mask = ~dev_priv->irq_mask;
        enable_mask &= ~(I915_DISPLAY_PLANE_A_FLIP_PENDING_INTERRUPT |
                         I915_DISPLAY_PLANE_B_FLIP_PENDING_INTERRUPT);
        enable_mask |= I915_USER_INTERRUPT;

        if (IS_G4X(dev))
                enable_mask |= I915_BSD_USER_INTERRUPT;

        /* Interrupt setup is already guaranteed to be single-threaded, this is
         * just to make the assert_spin_locked check happy. */
        spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
        i915_enable_pipestat(dev_priv, 0, PIPE_GMBUS_EVENT_ENABLE);
        spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);

        /*
         * Enable some error detection, note the instruction error mask
         * bit is reserved, so we leave it masked.
         */
        if (IS_G4X(dev)) {
                error_mask = ~(GM45_ERROR_PAGE_TABLE |
                               GM45_ERROR_MEM_PRIV |
                               GM45_ERROR_CP_PRIV |
                               I915_ERROR_MEMORY_REFRESH);
        } else {
                error_mask = ~(I915_ERROR_PAGE_TABLE |
                               I915_ERROR_MEMORY_REFRESH);
        }
        I915_WRITE(EMR, error_mask);

        I915_WRITE(IMR, dev_priv->irq_mask);
        I915_WRITE(IER, enable_mask);
        POSTING_READ(IER);

        I915_WRITE(PORT_HOTPLUG_EN, 0);
        POSTING_READ(PORT_HOTPLUG_EN);

        i915_enable_asle_pipestat(dev);

        return 0;
}

static void i915_hpd_irq_setup(struct drm_device *dev)
{
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
        struct drm_mode_config *mode_config = &dev->mode_config;
        struct intel_encoder *intel_encoder;
        u32 hotplug_en;

        assert_spin_locked(&dev_priv->irq_lock);

        if (I915_HAS_HOTPLUG(dev)) {
                hotplug_en = I915_READ(PORT_HOTPLUG_EN);
                hotplug_en &= ~HOTPLUG_INT_EN_MASK;
                /* Note HDMI and DP share hotplug bits */
                /* enable bits are the same for all generations */
                list_for_each_entry(intel_encoder, &mode_config->encoder_list, base.head)
                        if (dev_priv->hpd_stats[intel_encoder->hpd_pin].hpd_mark == HPD_ENABLED)
                                hotplug_en |= hpd_mask_i915[intel_encoder->hpd_pin];
                /* Programming the CRT detection parameters tends
                   to generate a spurious hotplug event about three
                   seconds later.  So just do it once.
                */
                if (IS_G4X(dev))
                        hotplug_en |= CRT_HOTPLUG_ACTIVATION_PERIOD_64;
                hotplug_en &= ~CRT_HOTPLUG_VOLTAGE_COMPARE_MASK;
                hotplug_en |= CRT_HOTPLUG_VOLTAGE_COMPARE_50;

                /* Ignore TV since it's buggy */
                I915_WRITE(PORT_HOTPLUG_EN, hotplug_en);
        }
}

static irqreturn_t i965_irq_handler(int irq, void *arg)
{
        struct drm_device *dev = (struct drm_device *) arg;
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
        u32 iir, new_iir;
        u32 pipe_stats[I915_MAX_PIPES];
        unsigned long irqflags;
        int irq_received;
        int ret = IRQ_NONE, pipe;
        u32 flip_mask =
                I915_DISPLAY_PLANE_A_FLIP_PENDING_INTERRUPT |
                I915_DISPLAY_PLANE_B_FLIP_PENDING_INTERRUPT;

        atomic_inc(&dev_priv->irq_received);

        iir = I915_READ(IIR);

        for (;;) {
                bool blc_event = false;

                irq_received = (iir & ~flip_mask) != 0;

                /* Can't rely on pipestat interrupt bit in iir as it might
                 * have been cleared after the pipestat interrupt was received.
                 * It doesn't set the bit in iir again, but it still produces
                 * interrupts (for non-MSI).
                 */
                spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
                if (iir & I915_RENDER_COMMAND_PARSER_ERROR_INTERRUPT)
                        i915_handle_error(dev, false);

                for_each_pipe(pipe) {
                        int reg = PIPESTAT(pipe);
                        pipe_stats[pipe] = I915_READ(reg);

                        /*
                         * Clear the PIPE*STAT regs before the IIR
                         */
                        if (pipe_stats[pipe] & 0x8000ffff) {
                                if (pipe_stats[pipe] & PIPE_FIFO_UNDERRUN_STATUS)
                                        DRM_DEBUG_DRIVER("pipe %c underrun\n",
                                                         pipe_name(pipe));
                                I915_WRITE(reg, pipe_stats[pipe]);
                                irq_received = 1;
                        }
                }
                spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);

                if (!irq_received)
                        break;

                ret = IRQ_HANDLED;

                /* Consume port.  Then clear IIR or we'll miss events */
                if (iir & I915_DISPLAY_PORT_INTERRUPT) {
                        u32 hotplug_status = I915_READ(PORT_HOTPLUG_STAT);
                        u32 hotplug_trigger = hotplug_status & (IS_G4X(dev) ?
                                                                  HOTPLUG_INT_STATUS_G4X :
                                                                  HOTPLUG_INT_STATUS_I915);

                        DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
                                  hotplug_status);

                        intel_hpd_irq_handler(dev, hotplug_trigger,
                                              IS_G4X(dev) ? hpd_status_gen4 : hpd_status_i915);

                        I915_WRITE(PORT_HOTPLUG_STAT, hotplug_status);
                        I915_READ(PORT_HOTPLUG_STAT);
                }