drm/i915: Fix use-before-null-check in i915_irq_emit().

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / gpu / drm / i915 / i915_irq.c

/* 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.
 *
 */

#include "drmP.h"
#include "drm.h"
#include "i915_drm.h"
#include "i915_drv.h"
#include "intel_drv.h"

#define MAX_NOPID ((u32)~0)

/**
 * Interrupts that are always left unmasked.
 *
 * Since pipe events are edge-triggered from the PIPESTAT register to IIR,
 * we leave them always unmasked in IMR and then control enabling them through
 * PIPESTAT alone.
 */
#define I915_INTERRUPT_ENABLE_FIX (I915_ASLE_INTERRUPT | \
                                   I915_DISPLAY_PIPE_A_EVENT_INTERRUPT |  \
                                   I915_DISPLAY_PIPE_B_EVENT_INTERRUPT)

/** Interrupts that we mask and unmask at runtime. */
#define I915_INTERRUPT_ENABLE_VAR (I915_USER_INTERRUPT)

/** These are all of the interrupts used by the driver */
#define I915_INTERRUPT_ENABLE_MASK (I915_INTERRUPT_ENABLE_FIX | \
                                    I915_INTERRUPT_ENABLE_VAR)

#define I915_PIPE_VBLANK_STATUS (PIPE_START_VBLANK_INTERRUPT_STATUS |\
                                 PIPE_VBLANK_INTERRUPT_STATUS)

#define I915_PIPE_VBLANK_ENABLE (PIPE_START_VBLANK_INTERRUPT_ENABLE |\
                                 PIPE_VBLANK_INTERRUPT_ENABLE)

#define DRM_I915_VBLANK_PIPE_ALL        (DRM_I915_VBLANK_PIPE_A | \
                                         DRM_I915_VBLANK_PIPE_B)

void
i915_enable_irq(drm_i915_private_t *dev_priv, u32 mask)
{
        if ((dev_priv->irq_mask_reg & mask) != 0) {
                dev_priv->irq_mask_reg &= ~mask;
                I915_WRITE(IMR, dev_priv->irq_mask_reg);
                (void) I915_READ(IMR);
        }
}

static inline void
i915_disable_irq(drm_i915_private_t *dev_priv, u32 mask)
{
        if ((dev_priv->irq_mask_reg & mask) != mask) {
                dev_priv->irq_mask_reg |= mask;
                I915_WRITE(IMR, dev_priv->irq_mask_reg);
                (void) I915_READ(IMR);
        }
}

static inline u32
i915_pipestat(int pipe)
{
        if (pipe == 0)
                return PIPEASTAT;
        if (pipe == 1)
                return PIPEBSTAT;
        BUG();
}

void
i915_enable_pipestat(drm_i915_private_t *dev_priv, int pipe, u32 mask)
{
        if ((dev_priv->pipestat[pipe] & mask) != mask) {
                u32 reg = i915_pipestat(pipe);

                dev_priv->pipestat[pipe] |= mask;
                /* Enable the interrupt, clear any pending status */
                I915_WRITE(reg, dev_priv->pipestat[pipe] | (mask >> 16));
                (void) I915_READ(reg);
        }
}

void
i915_disable_pipestat(drm_i915_private_t *dev_priv, int pipe, u32 mask)
{
        if ((dev_priv->pipestat[pipe] & mask) != 0) {
                u32 reg = i915_pipestat(pipe);

                dev_priv->pipestat[pipe] &= ~mask;
                I915_WRITE(reg, dev_priv->pipestat[pipe]);
                (void) I915_READ(reg);
        }
}

/**
 * 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;
        unsigned long pipeconf = pipe ? PIPEBCONF : PIPEACONF;

        if (I915_READ(pipeconf) & PIPEACONF_ENABLE)
                return 1;

        return 0;
}

/* Called from drm generic code, passed a 'crtc', which
 * we use as a pipe index
 */
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, count;

        high_frame = pipe ? PIPEBFRAMEHIGH : PIPEAFRAMEHIGH;
        low_frame = pipe ? PIPEBFRAMEPIXEL : PIPEAFRAMEPIXEL;

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

        /*
         * 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) >>
                         PIPE_FRAME_HIGH_SHIFT);
                low =  ((I915_READ(low_frame) & PIPE_FRAME_LOW_MASK) >>
                        PIPE_FRAME_LOW_SHIFT);
                high2 = ((I915_READ(high_frame) & PIPE_FRAME_HIGH_MASK) >>
                         PIPE_FRAME_HIGH_SHIFT);
        } while (high1 != high2);

        count = (high1 << 8) | low;

        return count;
}

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 ? PIPEB_FRMCOUNT_GM45 : PIPEA_FRMCOUNT_GM45;

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

        return I915_READ(reg);
}

irqreturn_t i915_driver_irq_handler(DRM_IRQ_ARGS)
{
        struct drm_device *dev = (struct drm_device *) arg;
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
        struct drm_i915_master_private *master_priv;
        u32 iir, new_iir;
        u32 pipea_stats, pipeb_stats;
        u32 vblank_status;
        u32 vblank_enable;
        int vblank = 0;
        unsigned long irqflags;
        int irq_received;
        int ret = IRQ_NONE;

        atomic_inc(&dev_priv->irq_received);

        iir = I915_READ(IIR);

        if (IS_I965G(dev)) {
                vblank_status = I915_START_VBLANK_INTERRUPT_STATUS;
                vblank_enable = PIPE_START_VBLANK_INTERRUPT_ENABLE;
        } else {
                vblank_status = I915_VBLANK_INTERRUPT_STATUS;
                vblank_enable = I915_VBLANK_INTERRUPT_ENABLE;
        }

        for (;;) {
                irq_received = iir != 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->user_irq_lock, irqflags);
                pipea_stats = I915_READ(PIPEASTAT);
                pipeb_stats = I915_READ(PIPEBSTAT);

                /*
                 * Clear the PIPE(A|B)STAT regs before the IIR
                 */
                if (pipea_stats & 0x8000ffff) {
                        I915_WRITE(PIPEASTAT, pipea_stats);
                        irq_received = 1;
                }

                if (pipeb_stats & 0x8000ffff) {
                        I915_WRITE(PIPEBSTAT, pipeb_stats);
                        irq_received = 1;
                }
                spin_unlock_irqrestore(&dev_priv->user_irq_lock, irqflags);

                if (!irq_received)
                        break;

                ret = IRQ_HANDLED;

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

                if (dev->primary->master) {
                        master_priv = dev->primary->master->driver_priv;
                        if (master_priv->sarea_priv)
                                master_priv->sarea_priv->last_dispatch =
                                        READ_BREADCRUMB(dev_priv);
                }

                if (iir & I915_USER_INTERRUPT) {
                        dev_priv->mm.irq_gem_seqno = i915_get_gem_seqno(dev);
                        DRM_WAKEUP(&dev_priv->irq_queue);
                }

                if (pipea_stats & vblank_status) {
                        vblank++;
                        drm_handle_vblank(dev, 0);
                }

                if (pipeb_stats & vblank_status) {
                        vblank++;
                        drm_handle_vblank(dev, 1);
                }

                if ((pipeb_stats & I915_LEGACY_BLC_EVENT_STATUS) ||
                    (iir & I915_ASLE_INTERRUPT))
                        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.
                 */
                iir = new_iir;
        }

        return ret;
}

static int i915_emit_irq(struct drm_device * dev)
{
        drm_i915_private_t *dev_priv = dev->dev_private;
        struct drm_i915_master_private *master_priv = dev->primary->master->driver_priv;
        RING_LOCALS;

        i915_kernel_lost_context(dev);

        DRM_DEBUG("\n");

        dev_priv->counter++;
        if (dev_priv->counter > 0x7FFFFFFFUL)
                dev_priv->counter = 1;
        if (master_priv->sarea_priv)
                master_priv->sarea_priv->last_enqueue = dev_priv->counter;

        BEGIN_LP_RING(4);
        OUT_RING(MI_STORE_DWORD_INDEX);
        OUT_RING(I915_BREADCRUMB_INDEX << MI_STORE_DWORD_INDEX_SHIFT);
        OUT_RING(dev_priv->counter);
        OUT_RING(MI_USER_INTERRUPT);
        ADVANCE_LP_RING();

        return dev_priv->counter;
}

void i915_user_irq_get(struct drm_device *dev)
{
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
        unsigned long irqflags;

        spin_lock_irqsave(&dev_priv->user_irq_lock, irqflags);
        if (dev->irq_enabled && (++dev_priv->user_irq_refcount == 1))
                i915_enable_irq(dev_priv, I915_USER_INTERRUPT);
        spin_unlock_irqrestore(&dev_priv->user_irq_lock, irqflags);
}

void i915_user_irq_put(struct drm_device *dev)
{
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
        unsigned long irqflags;

        spin_lock_irqsave(&dev_priv->user_irq_lock, irqflags);
        BUG_ON(dev->irq_enabled && dev_priv->user_irq_refcount <= 0);
        if (dev->irq_enabled && (--dev_priv->user_irq_refcount == 0))
                i915_disable_irq(dev_priv, I915_USER_INTERRUPT);
        spin_unlock_irqrestore(&dev_priv->user_irq_lock, irqflags);
}

static int i915_wait_irq(struct drm_device * dev, int irq_nr)
{
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
        struct drm_i915_master_private *master_priv = dev->primary->master->driver_priv;
        int ret = 0;

        DRM_DEBUG("irq_nr=%d breadcrumb=%d\n", irq_nr,
                  READ_BREADCRUMB(dev_priv));

        if (READ_BREADCRUMB(dev_priv) >= irq_nr) {
                if (master_priv->sarea_priv)
                        master_priv->sarea_priv->last_dispatch = READ_BREADCRUMB(dev_priv);
                return 0;
        }

        if (master_priv->sarea_priv)
                master_priv->sarea_priv->perf_boxes |= I915_BOX_WAIT;

        i915_user_irq_get(dev);
        DRM_WAIT_ON(ret, dev_priv->irq_queue, 3 * DRM_HZ,
                    READ_BREADCRUMB(dev_priv) >= irq_nr);
        i915_user_irq_put(dev);

        if (ret == -EBUSY) {
                DRM_ERROR("EBUSY -- rec: %d emitted: %d\n",
                          READ_BREADCRUMB(dev_priv), (int)dev_priv->counter);
        }

        return ret;
}

/* Needs the lock as it touches the ring.
 */
int i915_irq_emit(struct drm_device *dev, void *data,
                         struct drm_file *file_priv)
{
        drm_i915_private_t *dev_priv = dev->dev_private;
        drm_i915_irq_emit_t *emit = data;
        int result;

        if (!dev_priv) {
                DRM_ERROR("called with no initialization\n");
                return -EINVAL;
        }

        RING_LOCK_TEST_WITH_RETURN(dev, file_priv);

        mutex_lock(&dev->struct_mutex);
        result = i915_emit_irq(dev);
        mutex_unlock(&dev->struct_mutex);

        if (DRM_COPY_TO_USER(emit->irq_seq, &result, sizeof(int))) {
                DRM_ERROR("copy_to_user\n");
                return -EFAULT;
        }

        return 0;
}

/* Doesn't need the hardware lock.
 */
int i915_irq_wait(struct drm_device *dev, void *data,
                         struct drm_file *file_priv)
{
        drm_i915_private_t *dev_priv = dev->dev_private;
        drm_i915_irq_wait_t *irqwait = data;

        if (!dev_priv) {
                DRM_ERROR("called with no initialization\n");
                return -EINVAL;
        }

        return i915_wait_irq(dev, irqwait->irq_seq);
}

/* Called from drm generic code, passed 'crtc' which
 * we use as a pipe index
 */
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;
        int pipeconf_reg = (pipe == 0) ? PIPEACONF : PIPEBCONF;
        u32 pipeconf;

        pipeconf = I915_READ(pipeconf_reg);
        if (!(pipeconf & PIPEACONF_ENABLE))
                return -EINVAL;

        spin_lock_irqsave(&dev_priv->user_irq_lock, irqflags);
        if (IS_I965G(dev))
                i915_enable_pipestat(dev_priv, pipe,
                                     PIPE_START_VBLANK_INTERRUPT_ENABLE);
        else
                i915_enable_pipestat(dev_priv, pipe,
                                     PIPE_VBLANK_INTERRUPT_ENABLE);
        spin_unlock_irqrestore(&dev_priv->user_irq_lock, irqflags);
        return 0;
}

/* Called from drm generic code, passed 'crtc' which
 * we use as a pipe index
 */
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->user_irq_lock, irqflags);
        i915_disable_pipestat(dev_priv, pipe,
                              PIPE_VBLANK_INTERRUPT_ENABLE |
                              PIPE_START_VBLANK_INTERRUPT_ENABLE);
        spin_unlock_irqrestore(&dev_priv->user_irq_lock, irqflags);
}

void i915_enable_interrupt (struct drm_device *dev)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        opregion_enable_asle(dev);
        dev_priv->irq_enabled = 1;
}


/* Set the vblank monitor pipe
 */
int i915_vblank_pipe_set(struct drm_device *dev, void *data,
                         struct drm_file *file_priv)
{
        drm_i915_private_t *dev_priv = dev->dev_private;

        if (!dev_priv) {
                DRM_ERROR("called with no initialization\n");
                return -EINVAL;
        }

        return 0;
}

int i915_vblank_pipe_get(struct drm_device *dev, void *data,
                         struct drm_file *file_priv)
{
        drm_i915_private_t *dev_priv = dev->dev_private;
        drm_i915_vblank_pipe_t *pipe = data;

        if (!dev_priv) {
                DRM_ERROR("called with no initialization\n");
                return -EINVAL;
        }

        pipe->pipe = DRM_I915_VBLANK_PIPE_A | DRM_I915_VBLANK_PIPE_B;

        return 0;
}

/**
 * Schedule buffer swap at given vertical blank.
 */
int i915_vblank_swap(struct drm_device *dev, void *data,
                     struct drm_file *file_priv)
{
        /* The delayed swap mechanism was fundamentally racy, and has been
         * removed.  The model was that the client requested a delayed flip/swap
         * from the kernel, then waited for vblank before continuing to perform
         * rendering.  The problem was that the kernel might wake the client
         * up before it dispatched the vblank swap (since the lock has to be
         * held while touching the ringbuffer), in which case the client would
         * clear and start the next frame before the swap occurred, and
         * flicker would occur in addition to likely missing the vblank.
         *
         * In the absence of this ioctl, userland falls back to a correct path
         * of waiting for a vblank, then dispatching the swap on its own.
         * Context switching to userland and back is plenty fast enough for
         * meeting the requirements of vblank swapping.
         */
        return -EINVAL;
}

/* drm_dma.h hooks
*/
void i915_driver_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(PIPEASTAT, 0);
        I915_WRITE(PIPEBSTAT, 0);
        I915_WRITE(IMR, 0xffffffff);
        I915_WRITE(IER, 0x0);
        (void) I915_READ(IER);
}

int i915_driver_irq_postinstall(struct drm_device *dev)
{
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;

        dev_priv->vblank_pipe = DRM_I915_VBLANK_PIPE_A | DRM_I915_VBLANK_PIPE_B;

        dev->max_vblank_count = 0xffffff; /* only 24 bits of frame count */

        /* Unmask the interrupts that we always want on. */
        dev_priv->irq_mask_reg = ~I915_INTERRUPT_ENABLE_FIX;

        dev_priv->pipestat[0] = 0;
        dev_priv->pipestat[1] = 0;

        /* Disable pipe interrupt enables, clear pending pipe status */
        I915_WRITE(PIPEASTAT, I915_READ(PIPEASTAT) & 0x8000ffff);
        I915_WRITE(PIPEBSTAT, I915_READ(PIPEBSTAT) & 0x8000ffff);
        /* Clear pending interrupt status */
        I915_WRITE(IIR, I915_READ(IIR));

        I915_WRITE(IER, I915_INTERRUPT_ENABLE_MASK);
        I915_WRITE(IMR, dev_priv->irq_mask_reg);
        (void) I915_READ(IER);

        opregion_enable_asle(dev);
        DRM_INIT_WAITQUEUE(&dev_priv->irq_queue);

        return 0;
}

void i915_driver_irq_uninstall(struct drm_device * dev)
{
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;

        if (!dev_priv)
                return;

        dev_priv->vblank_pipe = 0;

        I915_WRITE(HWSTAM, 0xffffffff);
        I915_WRITE(PIPEASTAT, 0);
        I915_WRITE(PIPEBSTAT, 0);
        I915_WRITE(IMR, 0xffffffff);
        I915_WRITE(IER, 0x0);

        I915_WRITE(PIPEASTAT, I915_READ(PIPEASTAT) & 0x8000ffff);
        I915_WRITE(PIPEBSTAT, I915_READ(PIPEBSTAT) & 0x8000ffff);
        I915_WRITE(IIR, I915_READ(IIR));
}