/*
 * Copyright © 2008-2010 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 *
 * Authors:
 *    Eric Anholt <eric@anholt.net>
 *    Zou Nan hai <nanhai.zou@intel.com>
 *    Xiang Hai hao<haihao.xiang@intel.com>
 *
 */

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

/*
 * 965+ support PIPE_CONTROL commands, which provide finer grained control
 * over cache flushing.
 */
struct pipe_control {
        struct drm_i915_gem_object *obj;
        volatile u32 *cpu_page;
        u32 gtt_offset;
};

static inline int ring_space(struct intel_ring_buffer *ring)
{
        int space = (ring->head & HEAD_ADDR) - (ring->tail + 8);
        if (space < 0)
                space += ring->size;
        return space;
}

static int
gen2_render_ring_flush(struct intel_ring_buffer *ring,
                       u32      invalidate_domains,
                       u32      flush_domains)
{
        u32 cmd;
        int ret;

        cmd = MI_FLUSH;
        if (((invalidate_domains|flush_domains) & I915_GEM_DOMAIN_RENDER) == 0)
                cmd |= MI_NO_WRITE_FLUSH;

        if (invalidate_domains & I915_GEM_DOMAIN_SAMPLER)
                cmd |= MI_READ_FLUSH;

        ret = intel_ring_begin(ring, 2);
        if (ret)
                return ret;

        intel_ring_emit(ring, cmd);
        intel_ring_emit(ring, MI_NOOP);
        intel_ring_advance(ring);

        return 0;
}

static int
gen4_render_ring_flush(struct intel_ring_buffer *ring,
                       u32      invalidate_domains,
                       u32      flush_domains)
{
        struct drm_device *dev = ring->dev;
        u32 cmd;
        int ret;

        /*
         * read/write caches:
         *
         * I915_GEM_DOMAIN_RENDER is always invalidated, but is
         * only flushed if MI_NO_WRITE_FLUSH is unset.  On 965, it is
         * also flushed at 2d versus 3d pipeline switches.
         *
         * read-only caches:
         *
         * I915_GEM_DOMAIN_SAMPLER is flushed on pre-965 if
         * MI_READ_FLUSH is set, and is always flushed on 965.
         *
         * I915_GEM_DOMAIN_COMMAND may not exist?
         *
         * I915_GEM_DOMAIN_INSTRUCTION, which exists on 965, is
         * invalidated when MI_EXE_FLUSH is set.
         *
         * I915_GEM_DOMAIN_VERTEX, which exists on 965, is
         * invalidated with every MI_FLUSH.
         *
         * TLBs:
         *
         * On 965, TLBs associated with I915_GEM_DOMAIN_COMMAND
         * and I915_GEM_DOMAIN_CPU in are invalidated at PTE write and
         * I915_GEM_DOMAIN_RENDER and I915_GEM_DOMAIN_SAMPLER
         * are flushed at any MI_FLUSH.
         */

        cmd = MI_FLUSH | MI_NO_WRITE_FLUSH;
        if ((invalidate_domains|flush_domains) & I915_GEM_DOMAIN_RENDER)
                cmd &= ~MI_NO_WRITE_FLUSH;
        if (invalidate_domains & I915_GEM_DOMAIN_INSTRUCTION)
                cmd |= MI_EXE_FLUSH;

        if (invalidate_domains & I915_GEM_DOMAIN_COMMAND &&
            (IS_G4X(dev) || IS_GEN5(dev)))
                cmd |= MI_INVALIDATE_ISP;

        ret = intel_ring_begin(ring, 2);
        if (ret)
                return ret;

        intel_ring_emit(ring, cmd);
        intel_ring_emit(ring, MI_NOOP);
        intel_ring_advance(ring);

        return 0;
}

/**
 * Emits a PIPE_CONTROL with a non-zero post-sync operation, for
 * implementing two workarounds on gen6.  From section 1.4.7.1
 * "PIPE_CONTROL" of the Sandy Bridge PRM volume 2 part 1:
 *
 * [DevSNB-C+{W/A}] Before any depth stall flush (including those
 * produced by non-pipelined state commands), software needs to first
 * send a PIPE_CONTROL with no bits set except Post-Sync Operation !=
 * 0.
 *
 * [Dev-SNB{W/A}]: Before a PIPE_CONTROL with Write Cache Flush Enable
 * =1, a PIPE_CONTROL with any non-zero post-sync-op is required.
 *
 * And the workaround for these two requires this workaround first:
 *
 * [Dev-SNB{W/A}]: Pipe-control with CS-stall bit set must be sent
 * BEFORE the pipe-control with a post-sync op and no write-cache
 * flushes.
 *
 * And this last workaround is tricky because of the requirements on
 * that bit.  From section 1.4.7.2.3 "Stall" of the Sandy Bridge PRM
 * volume 2 part 1:
 *
 *     "1 of the following must also be set:
 *      - Render Target Cache Flush Enable ([12] of DW1)
 *      - Depth Cache Flush Enable ([0] of DW1)
 *      - Stall at Pixel Scoreboard ([1] of DW1)
 *      - Depth Stall ([13] of DW1)
 *      - Post-Sync Operation ([13] of DW1)
 *      - Notify Enable ([8] of DW1)"
 *
 * The cache flushes require the workaround flush that triggered this
 * one, so we can't use it.  Depth stall would trigger the same.
 * Post-sync nonzero is what triggered this second workaround, so we
 * can't use that one either.  Notify enable is IRQs, which aren't
 * really our business.  That leaves only stall at scoreboard.
 */
static int
intel_emit_post_sync_nonzero_flush(struct intel_ring_buffer *ring)
{
        struct pipe_control *pc = ring->private;
        u32 scratch_addr = pc->gtt_offset + 128;
        int ret;


        ret = intel_ring_begin(ring, 6);
        if (ret)
                return ret;

        intel_ring_emit(ring, GFX_OP_PIPE_CONTROL(5));
        intel_ring_emit(ring, PIPE_CONTROL_CS_STALL |
                        PIPE_CONTROL_STALL_AT_SCOREBOARD);
        intel_ring_emit(ring, scratch_addr | PIPE_CONTROL_GLOBAL_GTT); /* address */
        intel_ring_emit(ring, 0); /* low dword */
        intel_ring_emit(ring, 0); /* high dword */
        intel_ring_emit(ring, MI_NOOP);
        intel_ring_advance(ring);

        ret = intel_ring_begin(ring, 6);
        if (ret)
                return ret;

        intel_ring_emit(ring, GFX_OP_PIPE_CONTROL(5));
        intel_ring_emit(ring, PIPE_CONTROL_QW_WRITE);
        intel_ring_emit(ring, scratch_addr | PIPE_CONTROL_GLOBAL_GTT); /* address */
        intel_ring_emit(ring, 0);
        intel_ring_emit(ring, 0);
        intel_ring_emit(ring, MI_NOOP);
        intel_ring_advance(ring);

        return 0;
}

static int
gen6_render_ring_flush(struct intel_ring_buffer *ring,
                         u32 invalidate_domains, u32 flush_domains)
{
        u32 flags = 0;
        struct pipe_control *pc = ring->private;
        u32 scratch_addr = pc->gtt_offset + 128;
        int ret;

        /* Force SNB workarounds for PIPE_CONTROL flushes */
        ret = intel_emit_post_sync_nonzero_flush(ring);
        if (ret)
                return ret;

        /* Just flush everything.  Experiments have shown that reducing the
         * number of bits based on the write domains has little performance
         * impact.
         */
        if (flush_domains) {
                flags |= PIPE_CONTROL_RENDER_TARGET_CACHE_FLUSH;
                flags |= PIPE_CONTROL_DEPTH_CACHE_FLUSH;
                /*
                 * Ensure that any following seqno writes only happen
                 * when the render cache is indeed flushed.
                 */
                flags |= PIPE_CONTROL_CS_STALL;
        }
        if (invalidate_domains) {
                flags |= PIPE_CONTROL_TLB_INVALIDATE;
                flags |= PIPE_CONTROL_INSTRUCTION_CACHE_INVALIDATE;
                flags |= PIPE_CONTROL_TEXTURE_CACHE_INVALIDATE;
                flags |= PIPE_CONTROL_VF_CACHE_INVALIDATE;
                flags |= PIPE_CONTROL_CONST_CACHE_INVALIDATE;
                flags |= PIPE_CONTROL_STATE_CACHE_INVALIDATE;
                /*
                 * TLB invalidate requires a post-sync write.
                 */
                flags |= PIPE_CONTROL_QW_WRITE;
        }

        ret = intel_ring_begin(ring, 4);
        if (ret)
                return ret;

        intel_ring_emit(ring, GFX_OP_PIPE_CONTROL(4));
        intel_ring_emit(ring, flags);
        intel_ring_emit(ring, scratch_addr | PIPE_CONTROL_GLOBAL_GTT);
        intel_ring_emit(ring, 0);
        intel_ring_advance(ring);

        return 0;
}

static int
gen7_render_ring_cs_stall_wa(struct intel_ring_buffer *ring)
{
        int ret;

        ret = intel_ring_begin(ring, 4);
        if (ret)
                return ret;

        intel_ring_emit(ring, GFX_OP_PIPE_CONTROL(4));
        intel_ring_emit(ring, PIPE_CONTROL_CS_STALL |
                              PIPE_CONTROL_STALL_AT_SCOREBOARD);
        intel_ring_emit(ring, 0);
        intel_ring_emit(ring, 0);
        intel_ring_advance(ring);

        return 0;
}

static int
gen7_render_ring_flush(struct intel_ring_buffer *ring,
                       u32 invalidate_domains, u32 flush_domains)
{
        u32 flags = 0;
        struct pipe_control *pc = ring->private;
        u32 scratch_addr = pc->gtt_offset + 128;
        int ret;

        /*
         * Ensure that any following seqno writes only happen when the render
         * cache is indeed flushed.
         *
         * Workaround: 4th PIPE_CONTROL command (except the ones with only
         * read-cache invalidate bits set) must have the CS_STALL bit set. We
         * don't try to be clever and just set it unconditionally.
         */
        flags |= PIPE_CONTROL_CS_STALL;

        /* Just flush everything.  Experiments have shown that reducing the
         * number of bits based on the write domains has little performance
         * impact.
         */
        if (flush_domains) {
                flags |= PIPE_CONTROL_RENDER_TARGET_CACHE_FLUSH;
                flags |= PIPE_CONTROL_DEPTH_CACHE_FLUSH;
        }
        if (invalidate_domains) {
                flags |= PIPE_CONTROL_TLB_INVALIDATE;
                flags |= PIPE_CONTROL_INSTRUCTION_CACHE_INVALIDATE;
                flags |= PIPE_CONTROL_TEXTURE_CACHE_INVALIDATE;
                flags |= PIPE_CONTROL_VF_CACHE_INVALIDATE;
                flags |= PIPE_CONTROL_CONST_CACHE_INVALIDATE;
                flags |= PIPE_CONTROL_STATE_CACHE_INVALIDATE;
                /*
                 * TLB invalidate requires a post-sync write.
                 */
                flags |= PIPE_CONTROL_QW_WRITE;

                /* Workaround: we must issue a pipe_control with CS-stall bit
                 * set before a pipe_control command that has the state cache
                 * invalidate bit set. */
                gen7_render_ring_cs_stall_wa(ring);
        }

        ret = intel_ring_begin(ring, 4);
        if (ret)
                return ret;

        intel_ring_emit(ring, GFX_OP_PIPE_CONTROL(4));
        intel_ring_emit(ring, flags);
        intel_ring_emit(ring, scratch_addr | PIPE_CONTROL_GLOBAL_GTT);
        intel_ring_emit(ring, 0);
        intel_ring_advance(ring);

        return 0;
}

static void ring_write_tail(struct intel_ring_buffer *ring,
                            u32 value)
{
        drm_i915_private_t *dev_priv = ring->dev->dev_private;
        I915_WRITE_TAIL(ring, value);
}

u32 intel_ring_get_active_head(struct intel_ring_buffer *ring)
{
        drm_i915_private_t *dev_priv = ring->dev->dev_private;
        u32 acthd_reg = INTEL_INFO(ring->dev)->gen >= 4 ?
                        RING_ACTHD(ring->mmio_base) : ACTHD;

        return I915_READ(acthd_reg);
}

static int init_ring_common(struct intel_ring_buffer *ring)
{
        struct drm_device *dev = ring->dev;
        drm_i915_private_t *dev_priv = dev->dev_private;
        struct drm_i915_gem_object *obj = ring->obj;
        int ret = 0;
        u32 head;

        if (HAS_FORCE_WAKE(dev))
                gen6_gt_force_wake_get(dev_priv);

        /* Stop the ring if it's running. */
        I915_WRITE_CTL(ring, 0);
        I915_WRITE_HEAD(ring, 0);
        ring->write_tail(ring, 0);

        head = I915_READ_HEAD(ring) & HEAD_ADDR;

        /* G45 ring initialization fails to reset head to zero */
        if (head != 0) {
                DRM_DEBUG_KMS("%s head not reset to zero "
                              "ctl %08x head %08x tail %08x start %08x\n",
                              ring->name,
                              I915_READ_CTL(ring),
                              I915_READ_HEAD(ring),
                              I915_READ_TAIL(ring),
                              I915_READ_START(ring));

                I915_WRITE_HEAD(ring, 0);

                if (I915_READ_HEAD(ring) & HEAD_ADDR) {
                        DRM_ERROR("failed to set %s head to zero "
                                  "ctl %08x head %08x tail %08x start %08x\n",
                                  ring->name,
                                  I915_READ_CTL(ring),
                                  I915_READ_HEAD(ring),
                                  I915_READ_TAIL(ring),
                                  I915_READ_START(ring));
                }
        }

        /* Initialize the ring. This must happen _after_ we've cleared the ring
         * registers with the above sequence (the readback of the HEAD registers
         * also enforces ordering), otherwise the hw might lose the new ring
         * register values. */
        I915_WRITE_START(ring, obj->gtt_offset);
        I915_WRITE_CTL(ring,
                        ((ring->size - PAGE_SIZE) & RING_NR_PAGES)
                        | RING_VALID);

        /* If the head is still not zero, the ring is dead */
        if (wait_for((I915_READ_CTL(ring) & RING_VALID) != 0 &&
                     I915_READ_START(ring) == obj->gtt_offset &&
                     (I915_READ_HEAD(ring) & HEAD_ADDR) == 0, 50)) {
                DRM_ERROR("%s initialization failed "
                                "ctl %08x head %08x tail %08x start %08x\n",
                                ring->name,
                                I915_READ_CTL(ring),
                                I915_READ_HEAD(ring),
                                I915_READ_TAIL(ring),
                                I915_READ_START(ring));
                ret = -EIO;
                goto out;
        }

        if (!drm_core_check_feature(ring->dev, DRIVER_MODESET))
                i915_kernel_lost_context(ring->dev);
        else {
                ring->head = I915_READ_HEAD(ring);
                ring->tail = I915_READ_TAIL(ring) & TAIL_ADDR;
                ring->space = ring_space(ring);
                ring->last_retired_head = -1;
        }

out:
        if (HAS_FORCE_WAKE(dev))
                gen6_gt_force_wake_put(dev_priv);

        return ret;
}

static int
init_pipe_control(struct intel_ring_buffer *ring)
{
        struct pipe_control *pc;
        struct drm_i915_gem_object *obj;
        int ret;

        if (ring->private)
                return 0;

        pc = kmalloc(sizeof(*pc), GFP_KERNEL);
        if (!pc)
                return -ENOMEM;

        obj = i915_gem_alloc_object(ring->dev, 4096);
        if (obj == NULL) {
                DRM_ERROR("Failed to allocate seqno page\n");
                ret = -ENOMEM;
                goto err;
        }

        i915_gem_object_set_cache_level(obj, I915_CACHE_LLC);

        ret = i915_gem_object_pin(obj, 4096, true, false);
        if (ret)
                goto err_unref;

        pc->gtt_offset = obj->gtt_offset;
        pc->cpu_page =  kmap(sg_page(obj->pages->sgl));
        if (pc->cpu_page == NULL)
                goto err_unpin;

        pc->obj = obj;
        ring->private = pc;
        return 0;

err_unpin:
        i915_gem_object_unpin(obj);
err_unref:
        drm_gem_object_unreference(&obj->base);
err:
        kfree(pc);
        return ret;
}

static void
cleanup_pipe_control(struct intel_ring_buffer *ring)
{
        struct pipe_control *pc = ring->private;
        struct drm_i915_gem_object *obj;

        if (!ring->private)
                return;

        obj = pc->obj;

        kunmap(sg_page(obj->pages->sgl));
        i915_gem_object_unpin(obj);
        drm_gem_object_unreference(&obj->base);

        kfree(pc);
        ring->private = NULL;
}

static int init_render_ring(struct intel_ring_buffer *ring)
{
        struct drm_device *dev = ring->dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        int ret = init_ring_common(ring);

        if (INTEL_INFO(dev)->gen > 3) {
                I915_WRITE(MI_MODE, _MASKED_BIT_ENABLE(VS_TIMER_DISPATCH));
                if (IS_GEN7(dev))
                        I915_WRITE(GFX_MODE_GEN7,
                                   _MASKED_BIT_DISABLE(GFX_TLB_INVALIDATE_ALWAYS) |
                                   _MASKED_BIT_ENABLE(GFX_REPLAY_MODE));
        }

        if (INTEL_INFO(dev)->gen >= 5) {
                ret = init_pipe_control(ring);
                if (ret)
                        return ret;
        }

        if (IS_GEN6(dev)) {
                /* From the Sandybridge PRM, volume 1 part 3, page 24:
                 * "If this bit is set, STCunit will have LRA as replacement
                 *  policy. [...] This bit must be reset.  LRA replacement
                 *  policy is not supported."
                 */
                I915_WRITE(CACHE_MODE_0,
                           _MASKED_BIT_DISABLE(CM0_STC_EVICT_DISABLE_LRA_SNB));

                /* This is not explicitly set for GEN6, so read the register.
                 * see intel_ring_mi_set_context() for why we care.
                 * TODO: consider explicitly setting the bit for GEN5
                 */
                ring->itlb_before_ctx_switch =
                        !!(I915_READ(GFX_MODE) & GFX_TLB_INVALIDATE_ALWAYS);
        }

        if (INTEL_INFO(dev)->gen >= 6)
                I915_WRITE(INSTPM, _MASKED_BIT_ENABLE(INSTPM_FORCE_ORDERING));

        if (HAS_L3_GPU_CACHE(dev))
                I915_WRITE_IMR(ring, ~GEN6_RENDER_L3_PARITY_ERROR);

        return ret;
}

static void render_ring_cleanup(struct intel_ring_buffer *ring)
{
        if (!ring->private)
                return;

        cleanup_pipe_control(ring);
}

static void
update_mboxes(struct intel_ring_buffer *ring,
            u32 seqno,
            u32 mmio_offset)
{
        intel_ring_emit(ring, MI_SEMAPHORE_MBOX |
                              MI_SEMAPHORE_GLOBAL_GTT |
                              MI_SEMAPHORE_REGISTER |
                              MI_SEMAPHORE_UPDATE);
        intel_ring_emit(ring, seqno);
        intel_ring_emit(ring, mmio_offset);
}

/**
 * gen6_add_request - Update the semaphore mailbox registers
 * 
 * @ring - ring that is adding a request
 * @seqno - return seqno stuck into the ring
 *
 * Update the mailbox registers in the *other* rings with the current seqno.
 * This acts like a signal in the canonical semaphore.
 */
static int
gen6_add_request(struct intel_ring_buffer *ring,
                 u32 *seqno)
{
        u32 mbox1_reg;
        u32 mbox2_reg;
        int ret;

        ret = intel_ring_begin(ring, 10);
        if (ret)
                return ret;

        mbox1_reg = ring->signal_mbox[0];
        mbox2_reg = ring->signal_mbox[1];

        *seqno = i915_gem_next_request_seqno(ring);

        update_mboxes(ring, *seqno, mbox1_reg);
        update_mboxes(ring, *seqno, mbox2_reg);
        intel_ring_emit(ring, MI_STORE_DWORD_INDEX);
        intel_ring_emit(ring, I915_GEM_HWS_INDEX << MI_STORE_DWORD_INDEX_SHIFT);
        intel_ring_emit(ring, *seqno);
        intel_ring_emit(ring, MI_USER_INTERRUPT);
        intel_ring_advance(ring);

        return 0;
}

/**
 * intel_ring_sync - sync the waiter to the signaller on seqno
 *
 * @waiter - ring that is waiting
 * @signaller - ring which has, or will signal
 * @seqno - seqno which the waiter will block on
 */
static int
gen6_ring_sync(struct intel_ring_buffer *waiter,
               struct intel_ring_buffer *signaller,
               u32 seqno)
{
        int ret;
        u32 dw1 = MI_SEMAPHORE_MBOX |
                  MI_SEMAPHORE_COMPARE |
                  MI_SEMAPHORE_REGISTER;

        /* Throughout all of the GEM code, seqno passed implies our current
         * seqno is >= the last seqno executed. However for hardware the
         * comparison is strictly greater than.
         */
        seqno -= 1;

        WARN_ON(signaller->semaphore_register[waiter->id] ==
                MI_SEMAPHORE_SYNC_INVALID);

        ret = intel_ring_begin(waiter, 4);
        if (ret)
                return ret;

        intel_ring_emit(waiter,
                        dw1 | signaller->semaphore_register[waiter->id]);
        intel_ring_emit(waiter, seqno);
        intel_ring_emit(waiter, 0);
        intel_ring_emit(waiter, MI_NOOP);
        intel_ring_advance(waiter);

        return 0;
}

#define PIPE_CONTROL_FLUSH(ring__, addr__)                                      \
do {                                                                    \
        intel_ring_emit(ring__, GFX_OP_PIPE_CONTROL(4) | PIPE_CONTROL_QW_WRITE |                \
                 PIPE_CONTROL_DEPTH_STALL);                             \
        intel_ring_emit(ring__, (addr__) | PIPE_CONTROL_GLOBAL_GTT);                    \
        intel_ring_emit(ring__, 0);                                                     \
        intel_ring_emit(ring__, 0);                                                     \
} while (0)

static int
pc_render_add_request(struct intel_ring_buffer *ring,
                      u32 *result)
{
        u32 seqno = i915_gem_next_request_seqno(ring);
        struct pipe_control *pc = ring->private;
        u32 scratch_addr = pc->gtt_offset + 128;
        int ret;

        /* For Ironlake, MI_USER_INTERRUPT was deprecated and apparently
         * incoherent with writes to memory, i.e. completely fubar,
         * so we need to use PIPE_NOTIFY instead.
         *
         * However, we also need to workaround the qword write
         * incoherence by flushing the 6 PIPE_NOTIFY buffers out to
         * memory before requesting an interrupt.
         */
        ret = intel_ring_begin(ring, 32);
        if (ret)
                return ret;

        intel_ring_emit(ring, GFX_OP_PIPE_CONTROL(4) | PIPE_CONTROL_QW_WRITE |
                        PIPE_CONTROL_WRITE_FLUSH |
                        PIPE_CONTROL_TEXTURE_CACHE_INVALIDATE);
        intel_ring_emit(ring, pc->gtt_offset | PIPE_CONTROL_GLOBAL_GTT);
        intel_ring_emit(ring, seqno);
        intel_ring_emit(ring, 0);
        PIPE_CONTROL_FLUSH(ring, scratch_addr);
        scratch_addr += 128; /* write to separate cachelines */
        PIPE_CONTROL_FLUSH(ring, scratch_addr);
        scratch_addr += 128;
        PIPE_CONTROL_FLUSH(ring, scratch_addr);
        scratch_addr += 128;
        PIPE_CONTROL_FLUSH(ring, scratch_addr);
        scratch_addr += 128;
        PIPE_CONTROL_FLUSH(ring, scratch_addr);
        scratch_addr += 128;
        PIPE_CONTROL_FLUSH(ring, scratch_addr);

        intel_ring_emit(ring, GFX_OP_PIPE_CONTROL(4) | PIPE_CONTROL_QW_WRITE |
                        PIPE_CONTROL_WRITE_FLUSH |
                        PIPE_CONTROL_TEXTURE_CACHE_INVALIDATE |
                        PIPE_CONTROL_NOTIFY);
        intel_ring_emit(ring, pc->gtt_offset | PIPE_CONTROL_GLOBAL_GTT);
        intel_ring_emit(ring, seqno);
        intel_ring_emit(ring, 0);
        intel_ring_advance(ring);

        *result = seqno;
        return 0;
}

static u32
gen6_ring_get_seqno(struct intel_ring_buffer *ring, bool lazy_coherency)
{
        /* Workaround to force correct ordering between irq and seqno writes on
         * ivb (and maybe also on snb) by reading from a CS register (like
         * ACTHD) before reading the status page. */
        if (!lazy_coherency)
                intel_ring_get_active_head(ring);
        return intel_read_status_page(ring, I915_GEM_HWS_INDEX);
}

static u32
ring_get_seqno(struct intel_ring_buffer *ring, bool lazy_coherency)
{
        return intel_read_status_page(ring, I915_GEM_HWS_INDEX);
}

static u32
pc_render_get_seqno(struct intel_ring_buffer *ring, bool lazy_coherency)
{
        struct pipe_control *pc = ring->private;
        return pc->cpu_page[0];
}

static bool
gen5_ring_get_irq(struct intel_ring_buffer *ring)
{
        struct drm_device *dev = ring->dev;
        drm_i915_private_t *dev_priv = dev->dev_private;
        unsigned long flags;

        if (!dev->irq_enabled)
                return false;

        spin_lock_irqsave(&dev_priv->irq_lock, flags);
        if (ring->irq_refcount++ == 0) {
                dev_priv->gt_irq_mask &= ~ring->irq_enable_mask;
                I915_WRITE(GTIMR, dev_priv->gt_irq_mask);
                POSTING_READ(GTIMR);
        }
        spin_unlock_irqrestore(&dev_priv->irq_lock, flags);

        return true;
}

static void
gen5_ring_put_irq(struct intel_ring_buffer *ring)
{
        struct drm_device *dev = ring->dev;
        drm_i915_private_t *dev_priv = dev->dev_private;
        unsigned long flags;

        spin_lock_irqsave(&dev_priv->irq_lock, flags);
        if (--ring->irq_refcount == 0) {
                dev_priv->gt_irq_mask |= ring->irq_enable_mask;
                I915_WRITE(GTIMR, dev_priv->gt_irq_mask);
                POSTING_READ(GTIMR);
        }
        spin_unlock_irqrestore(&dev_priv->irq_lock, flags);
}

static bool
i9xx_ring_get_irq(struct intel_ring_buffer *ring)
{
        struct drm_device *dev = ring->dev;
        drm_i915_private_t *dev_priv = dev->dev_private;
        unsigned long flags;

        if (!dev->irq_enabled)
                return false;

        spin_lock_irqsave(&dev_priv->irq_lock, flags);
        if (ring->irq_refcount++ == 0) {
                dev_priv->irq_mask &= ~ring->irq_enable_mask;
                I915_WRITE(IMR, dev_priv->irq_mask);
                POSTING_READ(IMR);
        }
        spin_unlock_irqrestore(&dev_priv->irq_lock, flags);

        return true;
}

static void
i9xx_ring_put_irq(struct intel_ring_buffer *ring)
{
        struct drm_device *dev = ring->dev;
        drm_i915_private_t *dev_priv = dev->dev_private;
        unsigned long flags;

        spin_lock_irqsave(&dev_priv->irq_lock, flags);
        if (--ring->irq_refcount == 0) {
                dev_priv->irq_mask |= ring->irq_enable_mask;
                I915_WRITE(IMR, dev_priv->irq_mask);
                POSTING_READ(IMR);
        }
        spin_unlock_irqrestore(&dev_priv->irq_lock, flags);
}

static bool
i8xx_ring_get_irq(struct intel_ring_buffer *ring)
{
        struct drm_device *dev = ring->dev;
        drm_i915_private_t *dev_priv = dev->dev_private;
        unsigned long flags;

        if (!dev->irq_enabled)
                return false;

        spin_lock_irqsave(&dev_priv->irq_lock, flags);
        if (ring->irq_refcount++ == 0) {
                dev_priv->irq_mask &= ~ring->irq_enable_mask;
                I915_WRITE16(IMR, dev_priv->irq_mask);
                POSTING_READ16(IMR);
        }
        spin_unlock_irqrestore(&dev_priv->irq_lock, flags);

        return true;
}

static void
i8xx_ring_put_irq(struct intel_ring_buffer *ring)
{
        struct drm_device *dev = ring->dev;
        drm_i915_private_t *dev_priv = dev->dev_private;
        unsigned long flags;

        spin_lock_irqsave(&dev_priv->irq_lock, flags);
        if (--ring->irq_refcount == 0) {
                dev_priv->irq_mask |= ring->irq_enable_mask;
                I915_WRITE16(IMR, dev_priv->irq_mask);
                POSTING_READ16(IMR);
        }
        spin_unlock_irqrestore(&dev_priv->irq_lock, flags);
}

void intel_ring_setup_status_page(struct intel_ring_buffer *ring)
{
        struct drm_device *dev = ring->dev;
        drm_i915_private_t *dev_priv = ring->dev->dev_private;
        u32 mmio = 0;

        /* The ring status page addresses are no longer next to the rest of
         * the ring registers as of gen7.
         */
        if (IS_GEN7(dev)) {
                switch (ring->id) {
                case RCS:
                        mmio = RENDER_HWS_PGA_GEN7;
                        break;
                case BCS:
                        mmio = BLT_HWS_PGA_GEN7;
                        break;
                case VCS:
                        mmio = BSD_HWS_PGA_GEN7;
                        break;
                }
        } else if (IS_GEN6(ring->dev)) {
                mmio = RING_HWS_PGA_GEN6(ring->mmio_base);
        } else {
                mmio = RING_HWS_PGA(ring->mmio_base);
        }

        I915_WRITE(mmio, (u32)ring->status_page.gfx_addr);
        POSTING_READ(mmio);
}

static int
bsd_ring_flush(struct intel_ring_buffer *ring,
               u32     invalidate_domains,
               u32     flush_domains)
{
        int ret;

        ret = intel_ring_begin(ring, 2);
        if (ret)
                return ret;

        intel_ring_emit(ring, MI_FLUSH);
        intel_ring_emit(ring, MI_NOOP);
        intel_ring_advance(ring);
        return 0;
}

static int
i9xx_add_request(struct intel_ring_buffer *ring,
                 u32 *result)
{
        u32 seqno;
        int ret;

        ret = intel_ring_begin(ring, 4);
        if (ret)
                return ret;

        seqno = i915_gem_next_request_seqno(ring);

        intel_ring_emit(ring, MI_STORE_DWORD_INDEX);
        intel_ring_emit(ring, I915_GEM_HWS_INDEX << MI_STORE_DWORD_INDEX_SHIFT);
        intel_ring_emit(ring, seqno);
        intel_ring_emit(ring, MI_USER_INTERRUPT);
        intel_ring_advance(ring);

        *result = seqno;
        return 0;
}

static bool
gen6_ring_get_irq(struct intel_ring_buffer *ring)
{
        struct drm_device *dev = ring->dev;
        drm_i915_private_t *dev_priv = dev->dev_private;
        unsigned long flags;

        if (!dev->irq_enabled)
               return false;

        /* It looks like we need to prevent the gt from suspending while waiting
         * for an notifiy irq, otherwise irqs seem to get lost on at least the
         * blt/bsd rings on ivb. */
        gen6_gt_force_wake_get(dev_priv);

        spin_lock_irqsave(&dev_priv->irq_lock, flags);
        if (ring->irq_refcount++ == 0) {
                if (HAS_L3_GPU_CACHE(dev) && ring->id == RCS)
                        I915_WRITE_IMR(ring, ~(ring->irq_enable_mask |
                                                GEN6_RENDER_L3_PARITY_ERROR));
                else
                        I915_WRITE_IMR(ring, ~ring->irq_enable_mask);
                dev_priv->gt_irq_mask &= ~ring->irq_enable_mask;
                I915_WRITE(GTIMR, dev_priv->gt_irq_mask);
                POSTING_READ(GTIMR);
        }
        spin_unlock_irqrestore(&dev_priv->irq_lock, flags);

        return true;
}

static void
gen6_ring_put_irq(struct intel_ring_buffer *ring)
{
        struct drm_device *dev = ring->dev;
        drm_i915_private_t *dev_priv = dev->dev_private;
        unsigned long flags;

        spin_lock_irqsave(&dev_priv->irq_lock, flags);
        if (--ring->irq_refcount == 0) {
                if (HAS_L3_GPU_CACHE(dev) && ring->id == RCS)
                        I915_WRITE_IMR(ring, ~GEN6_RENDER_L3_PARITY_ERROR);
                else
                        I915_WRITE_IMR(ring, ~0);
                dev_priv->gt_irq_mask |= ring->irq_enable_mask;
                I915_WRITE(GTIMR, dev_priv->gt_irq_mask);
                POSTING_READ(GTIMR);
        }
        spin_unlock_irqrestore(&dev_priv->irq_lock, flags);

        gen6_gt_force_wake_put(dev_priv);
}

static int
i965_dispatch_execbuffer(struct intel_ring_buffer *ring, u32 offset, u32 length)
{
        int ret;

        ret = intel_ring_begin(ring, 2);
        if (ret)
                return ret;

        intel_ring_emit(ring,
                        MI_BATCH_BUFFER_START |
                        MI_BATCH_GTT |
                        MI_BATCH_NON_SECURE_I965);
        intel_ring_emit(ring, offset);
        intel_ring_advance(ring);

        return 0;
}

static int
i830_dispatch_execbuffer(struct intel_ring_buffer *ring,
                                u32 offset, u32 len)
{
        int ret;

        ret = intel_ring_begin(ring, 4);
        if (ret)
                return ret;

        intel_ring_emit(ring, MI_BATCH_BUFFER);
        intel_ring_emit(ring, offset | MI_BATCH_NON_SECURE);
        intel_ring_emit(ring, offset + len - 8);
        intel_ring_emit(ring, 0);
        intel_ring_advance(ring);

        return 0;
}

static int
i915_dispatch_execbuffer(struct intel_ring_buffer *ring,
                                u32 offset, u32 len)
{
        int ret;

        ret = intel_ring_begin(ring, 2);
        if (ret)
                return ret;

        intel_ring_emit(ring, MI_BATCH_BUFFER_START | MI_BATCH_GTT);
        intel_ring_emit(ring, offset | MI_BATCH_NON_SECURE);
        intel_ring_advance(ring);

        return 0;
}

static void cleanup_status_page(struct intel_ring_buffer *ring)
{
        struct drm_i915_gem_object *obj;

        obj = ring->status_page.obj;
        if (obj == NULL)
                return;

        kunmap(sg_page(obj->pages->sgl));
        i915_gem_object_unpin(obj);
        drm_gem_object_unreference(&obj->base);
        ring->status_page.obj = NULL;
}

static int init_status_page(struct intel_ring_buffer *ring)
{
        struct drm_device *dev = ring->dev;
        struct drm_i915_gem_object *obj;
        int ret;

        obj = i915_gem_alloc_object(dev, 4096);
        if (obj == NULL) {
                DRM_ERROR("Failed to allocate status page\n");
                ret = -ENOMEM;
                goto err;
        }

        i915_gem_object_set_cache_level(obj, I915_CACHE_LLC);

        ret = i915_gem_object_pin(obj, 4096, true, false);
        if (ret != 0) {
                goto err_unref;
        }

        ring->status_page.gfx_addr = obj->gtt_offset;
        ring->status_page.page_addr = kmap(sg_page(obj->pages->sgl));
        if (ring->status_page.page_addr == NULL) {
                ret = -ENOMEM;
                goto err_unpin;
        }
        ring->status_page.obj = obj;
        memset(ring->status_page.page_addr, 0, PAGE_SIZE);

        intel_ring_setup_status_page(ring);
        DRM_DEBUG_DRIVER("%s hws offset: 0x%08x\n",
                        ring->name, ring->status_page.gfx_addr);

        return 0;

err_unpin:
        i915_gem_object_unpin(obj);
err_unref:
        drm_gem_object_unreference(&obj->base);
err:
        return ret;
}

static int intel_init_ring_buffer(struct drm_device *dev,
                                  struct intel_ring_buffer *ring)
{
        struct drm_i915_gem_object *obj;
        struct drm_i915_private *dev_priv = dev->dev_private;
        int ret;

        ring->dev = dev;
        INIT_LIST_HEAD(&ring->active_list);
        INIT_LIST_HEAD(&ring->request_list);
        ring->size = 32 * PAGE_SIZE;

        init_waitqueue_head(&ring->irq_queue);

        if (I915_NEED_GFX_HWS(dev)) {
                ret = init_status_page(ring);
                if (ret)
                        return ret;
        }

        obj = i915_gem_alloc_object(dev, ring->size);
        if (obj == NULL) {
                DRM_ERROR("Failed to allocate ringbuffer\n");
                ret = -ENOMEM;
                goto err_hws;
        }

        ring->obj = obj;

        ret = i915_gem_object_pin(obj, PAGE_SIZE, true, false);
        if (ret)
                goto err_unref;

        ret = i915_gem_object_set_to_gtt_domain(obj, true);
        if (ret)
                goto err_unpin;

        ring->virtual_start =
                ioremap_wc(dev_priv->mm.gtt->gma_bus_addr + obj->gtt_offset,
                           ring->size);
        if (ring->virtual_start == NULL) {
                DRM_ERROR("Failed to map ringbuffer.\n");
                ret = -EINVAL;
                goto err_unpin;
        }

        ret = ring->init(ring);
        if (ret)
                goto err_unmap;

        /* Workaround an erratum on the i830 which causes a hang if
         * the TAIL pointer points to within the last 2 cachelines
         * of the buffer.
         */
        ring->effective_size = ring->size;
        if (IS_I830(ring->dev) || IS_845G(ring->dev))
                ring->effective_size -= 128;

        return 0;

err_unmap:
        iounmap(ring->virtual_start);
err_unpin:
        i915_gem_object_unpin(obj);
err_unref:
        drm_gem_object_unreference(&obj->base);
        ring->obj = NULL;
err_hws:
        cleanup_status_page(ring);
        return ret;
}

void intel_cleanup_ring_buffer(struct intel_ring_buffer *ring)
{
        struct drm_i915_private *dev_priv;
        int ret;

        if (ring->obj == NULL)
                return;

        /* Disable the ring buffer. The ring must be idle at this point */
        dev_priv = ring->dev->dev_private;
        ret = intel_wait_ring_idle(ring);
        if (ret)
                DRM_ERROR("failed to quiesce %s whilst cleaning up: %d\n",
                          ring->name, ret);

        I915_WRITE_CTL(ring, 0);

        iounmap(ring->virtual_start);

        i915_gem_object_unpin(ring->obj);
        drm_gem_object_unreference(&ring->obj->base);
        ring->obj = NULL;

        if (ring->cleanup)
                ring->cleanup(ring);

        cleanup_status_page(ring);
}

static int intel_wrap_ring_buffer(struct intel_ring_buffer *ring)
{
        uint32_t __iomem *virt;
        int rem = ring->size - ring->tail;

        if (ring->space < rem) {
                int ret = intel_wait_ring_buffer(ring, rem);
                if (ret)
                        return ret;
        }

        virt = ring->virtual_start + ring->tail;
        rem /= 4;
        while (rem--)
                iowrite32(MI_NOOP, virt++);

        ring->tail = 0;
        ring->space = ring_space(ring);

        return 0;
}

static int intel_ring_wait_seqno(struct intel_ring_buffer *ring, u32 seqno)
{
        int ret;

        ret = i915_wait_seqno(ring, seqno);
        if (!ret)
                i915_gem_retire_requests_ring(ring);

        return ret;
}

static int intel_ring_wait_request(struct intel_ring_buffer *ring, int n)
{
        struct drm_i915_gem_request *request;
        u32 seqno = 0;
        int ret;

        i915_gem_retire_requests_ring(ring);

        if (ring->last_retired_head != -1) {
                ring->head = ring->last_retired_head;
                ring->last_retired_head = -1;
                ring->space = ring_space(ring);
                if (ring->space >= n)
                        return 0;
        }

        list_for_each_entry(request, &ring->request_list, list) {
                int space;

                if (request->tail == -1)
                        continue;

                space = request->tail - (ring->tail + 8);
                if (space < 0)
                        space += ring->size;
                if (space >= n) {
                        seqno = request->seqno;
                        break;
                }

                /* Consume this request in case we need more space than
                 * is available and so need to prevent a race between
                 * updating last_retired_head and direct reads of
                 * I915_RING_HEAD. It also provides a nice sanity check.
                 */
                request->tail = -1;
        }

        if (seqno == 0)
                return -ENOSPC;

        ret = intel_ring_wait_seqno(ring, seqno);
        if (ret)
                return ret;

        if (WARN_ON(ring->last_retired_head == -1))
                return -ENOSPC;

        ring->head = ring->last_retired_head;
        ring->last_retired_head = -1;
        ring->space = ring_space(ring);
        if (WARN_ON(ring->space < n))
                return -ENOSPC;

        return 0;
}

int intel_wait_ring_buffer(struct intel_ring_buffer *ring, int n)
{
        struct drm_device *dev = ring->dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        unsigned long end;
        int ret;

        ret = intel_ring_wait_request(ring, n);
        if (ret != -ENOSPC)
                return ret;

        trace_i915_ring_wait_begin(ring);
        /* With GEM the hangcheck timer should kick us out of the loop,
         * leaving it early runs the risk of corrupting GEM state (due
         * to running on almost untested codepaths). But on resume
         * timers don't work yet, so prevent a complete hang in that
         * case by choosing an insanely large timeout. */
        end = jiffies + 60 * HZ;

        do {
                ring->head = I915_READ_HEAD(ring);
                ring->space = ring_space(ring);
                if (ring->space >= n) {
                        trace_i915_ring_wait_end(ring);
                        return 0;
                }

                if (dev->primary->master) {
                        struct drm_i915_master_private *master_priv = dev->primary->master->driver_priv;
                        if (master_priv->sarea_priv)
                                master_priv->sarea_priv->perf_boxes |= I915_BOX_WAIT;
                }

                msleep(1);

                ret = i915_gem_check_wedge(dev_priv, dev_priv->mm.interruptible);
                if (ret)
                        return ret;
        } while (!time_after(jiffies, end));
        trace_i915_ring_wait_end(ring);
        return -EBUSY;
}

int intel_ring_begin(struct intel_ring_buffer *ring,
                     int num_dwords)
{
        drm_i915_private_t *dev_priv = ring->dev->dev_private;
        int n = 4*num_dwords;
        int ret;

        ret = i915_gem_check_wedge(dev_priv, dev_priv->mm.interruptible);
        if (ret)
                return ret;

        if (unlikely(ring->tail + n > ring->effective_size)) {
                ret = intel_wrap_ring_buffer(ring);
                if (unlikely(ret))
                        return ret;
        }

        if (unlikely(ring->space < n)) {
                ret = intel_wait_ring_buffer(ring, n);
                if (unlikely(ret))
                        return ret;
        }

        ring->space -= n;
        return 0;
}

void intel_ring_advance(struct intel_ring_buffer *ring)
{
        struct drm_i915_private *dev_priv = ring->dev->dev_private;

        ring->tail &= ring->size - 1;
        if (dev_priv->stop_rings & intel_ring_flag(ring))
                return;
        ring->write_tail(ring, ring->tail);
}


static void gen6_bsd_ring_write_tail(struct intel_ring_buffer *ring,
                                     u32 value)
{
        drm_i915_private_t *dev_priv = ring->dev->dev_private;

       /* Every tail move must follow the sequence below */

        /* Disable notification that the ring is IDLE. The GT
         * will then assume that it is busy and bring it out of rc6.
         */
        I915_WRITE(GEN6_BSD_SLEEP_PSMI_CONTROL,
                   _MASKED_BIT_ENABLE(GEN6_BSD_SLEEP_MSG_DISABLE));

        /* Clear the context id. Here be magic! */
        I915_WRITE64(GEN6_BSD_RNCID, 0x0);

        /* Wait for the ring not to be idle, i.e. for it to wake up. */
        if (wait_for((I915_READ(GEN6_BSD_SLEEP_PSMI_CONTROL) &
                      GEN6_BSD_SLEEP_INDICATOR) == 0,
                     50))
                DRM_ERROR("timed out waiting for the BSD ring to wake up\n");

        /* Now that the ring is fully powered up, update the tail */
        I915_WRITE_TAIL(ring, value);
        POSTING_READ(RING_TAIL(ring->mmio_base));

        /* Let the ring send IDLE messages to the GT again,
         * and so let it sleep to conserve power when idle.
         */
        I915_WRITE(GEN6_BSD_SLEEP_PSMI_CONTROL,
                   _MASKED_BIT_DISABLE(GEN6_BSD_SLEEP_MSG_DISABLE));
}

static int gen6_ring_flush(struct intel_ring_buffer *ring,
                           u32 invalidate, u32 flush)
{
        uint32_t cmd;
        int ret;

        ret = intel_ring_begin(ring, 4);
        if (ret)
                return ret;

        cmd = MI_FLUSH_DW;
        if (invalidate & I915_GEM_GPU_DOMAINS)
                cmd |= MI_INVALIDATE_TLB | MI_INVALIDATE_BSD;
        intel_ring_emit(ring, cmd);
        intel_ring_emit(ring, 0);
        intel_ring_emit(ring, 0);
        intel_ring_emit(ring, MI_NOOP);
        intel_ring_advance(ring);
        return 0;
}

static int
gen6_ring_dispatch_execbuffer(struct intel_ring_buffer *ring,
                              u32 offset, u32 len)
{
        int ret;

        ret = intel_ring_begin(ring, 2);
        if (ret)
                return ret;

        intel_ring_emit(ring, MI_BATCH_BUFFER_START | MI_BATCH_NON_SECURE_I965);
        /* bit0-7 is the length on GEN6+ */
        intel_ring_emit(ring, offset);
        intel_ring_advance(ring);

        return 0;
}

/* Blitter support (SandyBridge+) */

static int blt_ring_flush(struct intel_ring_buffer *ring,
                          u32 invalidate, u32 flush)
{
        uint32_t cmd;
        int ret;

        ret = intel_ring_begin(ring, 4);
        if (ret)
                return ret;

        cmd = MI_FLUSH_DW;
        if (invalidate & I915_GEM_DOMAIN_RENDER)
                cmd |= MI_INVALIDATE_TLB;
        intel_ring_emit(ring, cmd);
        intel_ring_emit(ring, 0);
        intel_ring_emit(ring, 0);
        intel_ring_emit(ring, MI_NOOP);
        intel_ring_advance(ring);
        return 0;
}

int intel_init_render_ring_buffer(struct drm_device *dev)
{
        drm_i915_private_t *dev_priv = dev->dev_private;
        struct intel_ring_buffer *ring = &dev_priv->ring[RCS];

        ring->name = "render ring";
        ring->id = RCS;
        ring->mmio_base = RENDER_RING_BASE;

        if (INTEL_INFO(dev)->gen >= 6) {
                ring->add_request = gen6_add_request;
                ring->flush = gen7_render_ring_flush;
                if (INTEL_INFO(dev)->gen == 6)
                        ring->flush = gen6_render_ring_flush;
                ring->irq_get = gen6_ring_get_irq;
                ring->irq_put = gen6_ring_put_irq;
                ring->irq_enable_mask = GT_USER_INTERRUPT;
                ring->get_seqno = gen6_ring_get_seqno;
                ring->sync_to = gen6_ring_sync;
                ring->semaphore_register[0] = MI_SEMAPHORE_SYNC_INVALID;
                ring->semaphore_register[1] = MI_SEMAPHORE_SYNC_RV;
                ring->semaphore_register[2] = MI_SEMAPHORE_SYNC_RB;
                ring->signal_mbox[0] = GEN6_VRSYNC;
                ring->signal_mbox[1] = GEN6_BRSYNC;
        } else if (IS_GEN5(dev)) {
                ring->add_request = pc_render_add_request;
                ring->flush = gen4_render_ring_flush;
                ring->get_seqno = pc_render_get_seqno;
                ring->irq_get = gen5_ring_get_irq;
                ring->irq_put = gen5_ring_put_irq;
                ring->irq_enable_mask = GT_USER_INTERRUPT | GT_PIPE_NOTIFY;
        } else {
                ring->add_request = i9xx_add_request;
                if (INTEL_INFO(dev)->gen < 4)
                        ring->flush = gen2_render_ring_flush;
                else
                        ring->flush = gen4_render_ring_flush;
                ring->get_seqno = ring_get_seqno;
                if (IS_GEN2(dev)) {
                        ring->irq_get = i8xx_ring_get_irq;
                        ring->irq_put = i8xx_ring_put_irq;
                } else {
                        ring->irq_get = i9xx_ring_get_irq;
                        ring->irq_put = i9xx_ring_put_irq;
                }
                ring->irq_enable_mask = I915_USER_INTERRUPT;
        }
        ring->write_tail = ring_write_tail;
        if (INTEL_INFO(dev)->gen >= 6)
                ring->dispatch_execbuffer = gen6_ring_dispatch_execbuffer;
        else if (INTEL_INFO(dev)->gen >= 4)
                ring->dispatch_execbuffer = i965_dispatch_execbuffer;
        else if (IS_I830(dev) || IS_845G(dev))
                ring->dispatch_execbuffer = i830_dispatch_execbuffer;
        else
                ring->dispatch_execbuffer = i915_dispatch_execbuffer;
        ring->init = init_render_ring;
        ring->cleanup = render_ring_cleanup;


        if (!I915_NEED_GFX_HWS(dev)) {
                ring->status_page.page_addr = dev_priv->status_page_dmah->vaddr;
                memset(ring->status_page.page_addr, 0, PAGE_SIZE);
        }

        return intel_init_ring_buffer(dev, ring);
}

int intel_render_ring_init_dri(struct drm_device *dev, u64 start, u32 size)
{
        drm_i915_private_t *dev_priv = dev->dev_private;
        struct intel_ring_buffer *ring = &dev_priv->ring[RCS];

        ring->name = "render ring";
        ring->id = RCS;
        ring->mmio_base = RENDER_RING_BASE;

        if (INTEL_INFO(dev)->gen >= 6) {
                /* non-kms not supported on gen6+ */
                return -ENODEV;
        }

        /* Note: gem is not supported on gen5/ilk without kms (the corresponding
         * gem_init ioctl returns with -ENODEV). Hence we do not need to set up
         * the special gen5 functions. */
        ring->add_request = i9xx_add_request;
        if (INTEL_INFO(dev)->gen < 4)
                ring->flush = gen2_render_ring_flush;
        else
                ring->flush = gen4_render_ring_flush;
        ring->get_seqno = ring_get_seqno;
        if (IS_GEN2(dev)) {
                ring->irq_get = i8xx_ring_get_irq;
                ring->irq_put = i8xx_ring_put_irq;
        } else {
                ring->irq_get = i9xx_ring_get_irq;
                ring->irq_put = i9xx_ring_put_irq;
        }
        ring->irq_enable_mask = I915_USER_INTERRUPT;
        ring->write_tail = ring_write_tail;
        if (INTEL_INFO(dev)->gen >= 4)
                ring->dispatch_execbuffer = i965_dispatch_execbuffer;
        else if (IS_I830(dev) || IS_845G(dev))
                ring->dispatch_execbuffer = i830_dispatch_execbuffer;
        else
                ring->dispatch_execbuffer = i915_dispatch_execbuffer;
        ring->init = init_render_ring;
        ring->cleanup = render_ring_cleanup;

        if (!I915_NEED_GFX_HWS(dev))
                ring->status_page.page_addr = dev_priv->status_page_dmah->vaddr;

        ring->dev = dev;
        INIT_LIST_HEAD(&ring->active_list);
        INIT_LIST_HEAD(&ring->request_list);

        ring->size = size;
        ring->effective_size = ring->size;
        if (IS_I830(ring->dev))
                ring->effective_size -= 128;

        ring->virtual_start = ioremap_wc(start, size);
        if (ring->virtual_start == NULL) {
                DRM_ERROR("can not ioremap virtual address for"
                          " ring buffer\n");
                return -ENOMEM;
        }

        return 0;
}

int intel_init_bsd_ring_buffer(struct drm_device *dev)
{
        drm_i915_private_t *dev_priv = dev->dev_private;
        struct intel_ring_buffer *ring = &dev_priv->ring[VCS];

        ring->name = "bsd ring";
        ring->id = VCS;

        ring->write_tail = ring_write_tail;
        if (IS_GEN6(dev) || IS_GEN7(dev)) {
                ring->mmio_base = GEN6_BSD_RING_BASE;
                /* gen6 bsd needs a special wa for tail updates */
                if (IS_GEN6(dev))
                        ring->write_tail = gen6_bsd_ring_write_tail;
                ring->flush = gen6_ring_flush;
                ring->add_request = gen6_add_request;
                ring->get_seqno = gen6_ring_get_seqno;
                ring->irq_enable_mask = GEN6_BSD_USER_INTERRUPT;
                ring->irq_get = gen6_ring_get_irq;
                ring->irq_put = gen6_ring_put_irq;
                ring->dispatch_execbuffer = gen6_ring_dispatch_execbuffer;
                ring->sync_to = gen6_ring_sync;
                ring->semaphore_register[0] = MI_SEMAPHORE_SYNC_VR;
                ring->semaphore_register[1] = MI_SEMAPHORE_SYNC_INVALID;
                ring->semaphore_register[2] = MI_SEMAPHORE_SYNC_VB;
                ring->signal_mbox[0] = GEN6_RVSYNC;
                ring->signal_mbox[1] = GEN6_BVSYNC;
        } else {
                ring->mmio_base = BSD_RING_BASE;
                ring->flush = bsd_ring_flush;
                ring->add_request = i9xx_add_request;
                ring->get_seqno = ring_get_seqno;
                if (IS_GEN5(dev)) {
                        ring->irq_enable_mask = GT_BSD_USER_INTERRUPT;
                        ring->irq_get = gen5_ring_get_irq;
                        ring->irq_put = gen5_ring_put_irq;
                } else {
                        ring->irq_enable_mask = I915_BSD_USER_INTERRUPT;
                        ring->irq_get = i9xx_ring_get_irq;
                        ring->irq_put = i9xx_ring_put_irq;
                }
                ring->dispatch_execbuffer = i965_dispatch_execbuffer;
        }
        ring->init = init_ring_common;


        return intel_init_ring_buffer(dev, ring);
}

int intel_init_blt_ring_buffer(struct drm_device *dev)
{
        drm_i915_private_t *dev_priv = dev->dev_private;
        struct intel_ring_buffer *ring = &dev_priv->ring[BCS];

        ring->name = "blitter ring";
        ring->id = BCS;

        ring->mmio_base = BLT_RING_BASE;
        ring->write_tail = ring_write_tail;
        ring->flush = blt_ring_flush;
        ring->add_request = gen6_add_request;
        ring->get_seqno = gen6_ring_get_seqno;
        ring->irq_enable_mask = GEN6_BLITTER_USER_INTERRUPT;
        ring->irq_get = gen6_ring_get_irq;
        ring->irq_put = gen6_ring_put_irq;
        ring->dispatch_execbuffer = gen6_ring_dispatch_execbuffer;
        ring->sync_to = gen6_ring_sync;
        ring->semaphore_register[0] = MI_SEMAPHORE_SYNC_BR;
        ring->semaphore_register[1] = MI_SEMAPHORE_SYNC_BV;
        ring->semaphore_register[2] = MI_SEMAPHORE_SYNC_INVALID;
        ring->signal_mbox[0] = GEN6_RBSYNC;
        ring->signal_mbox[1] = GEN6_VBSYNC;
        ring->init = init_ring_common;

        return intel_init_ring_buffer(dev, ring);
}

int
intel_ring_flush_all_caches(struct intel_ring_buffer *ring)
{
        int ret;

        if (!ring->gpu_caches_dirty)
                return 0;

        ret = ring->flush(ring, 0, I915_GEM_GPU_DOMAINS);
        if (ret)
                return ret;

        trace_i915_gem_ring_flush(ring, 0, I915_GEM_GPU_DOMAINS);

        ring->gpu_caches_dirty = false;
        return 0;
}

int
intel_ring_invalidate_all_caches(struct intel_ring_buffer *ring)
{
        uint32_t flush_domains;
        int ret;

        flush_domains = 0;
        if (ring->gpu_caches_dirty)
                flush_domains = I915_GEM_GPU_DOMAINS;

        ret = ring->flush(ring, I915_GEM_GPU_DOMAINS, flush_domains);
        if (ret)
                return ret;

        trace_i915_gem_ring_flush(ring, I915_GEM_GPU_DOMAINS, flush_domains);

        ring->gpu_caches_dirty = false;
        return 0;
}