drm/i915/ringbuffer: Be consistent in use of ring->size when initialising

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

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

static u32 i915_gem_get_seqno(struct drm_device *dev)
{
        drm_i915_private_t *dev_priv = dev->dev_private;
        u32 seqno;

        seqno = dev_priv->next_seqno;

        /* reserve 0 for non-seqno */
        if (++dev_priv->next_seqno == 0)
                dev_priv->next_seqno = 1;

        return seqno;
}

static void
render_ring_flush(struct intel_ring_buffer *ring,
                  u32   invalidate_domains,
                  u32   flush_domains)
{
        struct drm_device *dev = ring->dev;
        drm_i915_private_t *dev_priv = dev->dev_private;
        u32 cmd;

#if WATCH_EXEC
        DRM_INFO("%s: invalidate %08x flush %08x\n", __func__,
                  invalidate_domains, flush_domains);
#endif

        trace_i915_gem_request_flush(dev, dev_priv->next_seqno,
                                     invalidate_domains, flush_domains);

        if ((invalidate_domains | flush_domains) & I915_GEM_GPU_DOMAINS) {
                /*
                 * 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 (INTEL_INFO(dev)->gen < 4) {
                        /*
                         * On the 965, the sampler cache always gets flushed
                         * and this bit is reserved.
                         */
                        if (invalidate_domains & I915_GEM_DOMAIN_SAMPLER)
                                cmd |= MI_READ_FLUSH;
                }
                if (invalidate_domains & I915_GEM_DOMAIN_INSTRUCTION)
                        cmd |= MI_EXE_FLUSH;

#if WATCH_EXEC
                DRM_INFO("%s: queue flush %08x to ring\n", __func__, cmd);
#endif
                if (intel_ring_begin(ring, 2) == 0) {
                        intel_ring_emit(ring, cmd);
                        intel_ring_emit(ring, MI_NOOP);
                        intel_ring_advance(ring);
                }
        }
}

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)
{
        drm_i915_private_t *dev_priv = ring->dev->dev_private;
        struct drm_i915_gem_object *obj_priv = to_intel_bo(ring->gem_object);
        u32 head;

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

        /* Initialize the ring. */
        I915_WRITE_START(ring, obj_priv->gtt_offset);
        head = I915_READ_HEAD(ring) & HEAD_ADDR;

        /* G45 ring initialization fails to reset head to zero */
        if (head != 0) {
                DRM_ERROR("%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);

                DRM_ERROR("%s head forced 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_CTL(ring,
                        ((ring->size - PAGE_SIZE) & RING_NR_PAGES)
                        | RING_REPORT_64K | RING_VALID);

        /* If the head is still not zero, the ring is dead */
        if ((I915_READ_CTL(ring) & RING_VALID) == 0 ||
            I915_READ_START(ring) != obj_priv->gtt_offset ||
            (I915_READ_HEAD(ring) & HEAD_ADDR) != 0) {
                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));
                return -EIO;
        }

        if (!drm_core_check_feature(ring->dev, DRIVER_MODESET))
                i915_kernel_lost_context(ring->dev);
        else {
                ring->head = I915_READ_HEAD(ring) & HEAD_ADDR;
                ring->tail = I915_READ_TAIL(ring) & TAIL_ADDR;
                ring->space = ring->head - (ring->tail + 8);
                if (ring->space < 0)
                        ring->space += ring->size;
        }
        return 0;
}

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

        if (INTEL_INFO(dev)->gen > 3) {
                drm_i915_private_t *dev_priv = dev->dev_private;
                int mode = VS_TIMER_DISPATCH << 16 | VS_TIMER_DISPATCH;
                if (IS_GEN6(dev))
                        mode |= MI_FLUSH_ENABLE << 16 | MI_FLUSH_ENABLE;
                I915_WRITE(MI_MODE, mode);
        }

        return ret;
}

#define PIPE_CONTROL_FLUSH(ring__, addr__)                                      \
do {                                                                    \
        intel_ring_emit(ring__, GFX_OP_PIPE_CONTROL | PIPE_CONTROL_QW_WRITE |           \
                 PIPE_CONTROL_DEPTH_STALL | 2);                         \
        intel_ring_emit(ring__, (addr__) | PIPE_CONTROL_GLOBAL_GTT);                    \
        intel_ring_emit(ring__, 0);                                                     \
        intel_ring_emit(ring__, 0);                                                     \
} while (0)

/**
 * Creates a new sequence number, emitting a write of it to the status page
 * plus an interrupt, which will trigger i915_user_interrupt_handler.
 *
 * Must be called with struct_lock held.
 *
 * Returned sequence numbers are nonzero on success.
 */
static int
render_ring_add_request(struct intel_ring_buffer *ring,
                        u32 *result)
{
        struct drm_device *dev = ring->dev;
        drm_i915_private_t *dev_priv = dev->dev_private;
        u32 seqno = i915_gem_get_seqno(dev);
        int ret;

        if (IS_GEN6(dev)) {
                ret = intel_ring_begin(ring, 6);
                if (ret)
                    return ret;

                intel_ring_emit(ring, GFX_OP_PIPE_CONTROL | 3);
                intel_ring_emit(ring, PIPE_CONTROL_QW_WRITE |
                                PIPE_CONTROL_WC_FLUSH | PIPE_CONTROL_IS_FLUSH |
                                PIPE_CONTROL_NOTIFY);
                intel_ring_emit(ring, dev_priv->seqno_gfx_addr | PIPE_CONTROL_GLOBAL_GTT);
                intel_ring_emit(ring, seqno);
                intel_ring_emit(ring, 0);
                intel_ring_emit(ring, 0);
        } else if (HAS_PIPE_CONTROL(dev)) {
                u32 scratch_addr = dev_priv->seqno_gfx_addr + 128;

                /*
                 * Workaround qword write incoherence by flushing the
                 * 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 | PIPE_CONTROL_QW_WRITE |
                                PIPE_CONTROL_WC_FLUSH | PIPE_CONTROL_TC_FLUSH);
                intel_ring_emit(ring, dev_priv->seqno_gfx_addr | 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 | PIPE_CONTROL_QW_WRITE |
                                PIPE_CONTROL_WC_FLUSH | PIPE_CONTROL_TC_FLUSH |
                                PIPE_CONTROL_NOTIFY);
                intel_ring_emit(ring, dev_priv->seqno_gfx_addr | PIPE_CONTROL_GLOBAL_GTT);
                intel_ring_emit(ring, seqno);
                intel_ring_emit(ring, 0);
        } else {
                ret = intel_ring_begin(ring, 4);
                if (ret)
                    return ret;

                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 u32
render_ring_get_seqno(struct intel_ring_buffer *ring)
{
        struct drm_device *dev = ring->dev;
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
        if (HAS_PIPE_CONTROL(dev))
                return ((volatile u32 *)(dev_priv->seqno_page))[0];
        else
                return intel_read_status_page(ring, I915_GEM_HWS_INDEX);
}

static void
render_ring_get_user_irq(struct intel_ring_buffer *ring)
{
        struct drm_device *dev = ring->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 && (++ring->user_irq_refcount == 1)) {
                if (HAS_PCH_SPLIT(dev))
                        ironlake_enable_graphics_irq(dev_priv, GT_PIPE_NOTIFY);
                else
                        i915_enable_irq(dev_priv, I915_USER_INTERRUPT);
        }
        spin_unlock_irqrestore(&dev_priv->user_irq_lock, irqflags);
}

static void
render_ring_put_user_irq(struct intel_ring_buffer *ring)
{
        struct drm_device *dev = ring->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 && ring->user_irq_refcount <= 0);
        if (dev->irq_enabled && (--ring->user_irq_refcount == 0)) {
                if (HAS_PCH_SPLIT(dev))
                        ironlake_disable_graphics_irq(dev_priv, GT_PIPE_NOTIFY);
                else
                        i915_disable_irq(dev_priv, I915_USER_INTERRUPT);
        }
        spin_unlock_irqrestore(&dev_priv->user_irq_lock, irqflags);
}

void intel_ring_setup_status_page(struct intel_ring_buffer *ring)
{
        drm_i915_private_t *dev_priv = ring->dev->dev_private;
        u32 mmio = IS_GEN6(ring->dev) ?
                RING_HWS_PGA_GEN6(ring->mmio_base) :
                RING_HWS_PGA(ring->mmio_base);
        I915_WRITE(mmio, (u32)ring->status_page.gfx_addr);
        POSTING_READ(mmio);
}

static void
bsd_ring_flush(struct intel_ring_buffer *ring,
               u32     invalidate_domains,
               u32     flush_domains)
{
        if (intel_ring_begin(ring, 2) == 0) {
                intel_ring_emit(ring, MI_FLUSH);
                intel_ring_emit(ring, MI_NOOP);
                intel_ring_advance(ring);
        }
}

static int
ring_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_get_seqno(ring->dev);

        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);

        DRM_DEBUG_DRIVER("%s %d\n", ring->name, seqno);
        *result = seqno;
        return 0;
}

static void
bsd_ring_get_user_irq(struct intel_ring_buffer *ring)
{
        /* do nothing */
}
static void
bsd_ring_put_user_irq(struct intel_ring_buffer *ring)
{
        /* do nothing */
}

static u32
ring_status_page_get_seqno(struct intel_ring_buffer *ring)
{
        return intel_read_status_page(ring, I915_GEM_HWS_INDEX);
}

static int
ring_dispatch_execbuffer(struct intel_ring_buffer *ring,
                         struct drm_i915_gem_execbuffer2 *exec,
                         struct drm_clip_rect *cliprects,
                         uint64_t exec_offset)
{
        uint32_t exec_start;
        int ret;

        exec_start = (uint32_t) exec_offset + exec->batch_start_offset;

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

        intel_ring_emit(ring,
                        MI_BATCH_BUFFER_START |
                        (2 << 6) |
                        MI_BATCH_NON_SECURE_I965);
        intel_ring_emit(ring, exec_start);
        intel_ring_advance(ring);

        return 0;
}

static int
render_ring_dispatch_execbuffer(struct intel_ring_buffer *ring,
                                struct drm_i915_gem_execbuffer2 *exec,
                                struct drm_clip_rect *cliprects,
                                uint64_t exec_offset)
{
        struct drm_device *dev = ring->dev;
        drm_i915_private_t *dev_priv = dev->dev_private;
        int nbox = exec->num_cliprects;
        uint32_t exec_start, exec_len;
        int i, count, ret;

        exec_start = (uint32_t) exec_offset + exec->batch_start_offset;
        exec_len = (uint32_t) exec->batch_len;

        trace_i915_gem_request_submit(dev, dev_priv->next_seqno + 1);

        count = nbox ? nbox : 1;
        for (i = 0; i < count; i++) {
                if (i < nbox) {
                        ret = i915_emit_box(dev, cliprects, i,
                                            exec->DR1, exec->DR4);
                        if (ret)
                                return ret;
                }

                if (IS_I830(dev) || IS_845G(dev)) {
                        ret = intel_ring_begin(ring, 4);
                        if (ret)
                                return ret;

                        intel_ring_emit(ring, MI_BATCH_BUFFER);
                        intel_ring_emit(ring, exec_start | MI_BATCH_NON_SECURE);
                        intel_ring_emit(ring, exec_start + exec_len - 4);
                        intel_ring_emit(ring, 0);
                } else {
                        ret = intel_ring_begin(ring, 2);
                        if (ret)
                                return ret;

                        if (INTEL_INFO(dev)->gen >= 4) {
                                intel_ring_emit(ring,
                                                MI_BATCH_BUFFER_START | (2 << 6)
                                                | MI_BATCH_NON_SECURE_I965);
                                intel_ring_emit(ring, exec_start);
                        } else {
                                intel_ring_emit(ring, MI_BATCH_BUFFER_START
                                                | (2 << 6));
                                intel_ring_emit(ring, exec_start |
                                                MI_BATCH_NON_SECURE);
                        }
                }
                intel_ring_advance(ring);
        }

        if (IS_G4X(dev) || IS_GEN5(dev)) {
                if (intel_ring_begin(ring, 2) == 0) {
                        intel_ring_emit(ring, MI_FLUSH |
                                        MI_NO_WRITE_FLUSH |
                                        MI_INVALIDATE_ISP );
                        intel_ring_emit(ring, MI_NOOP);
                        intel_ring_advance(ring);
                }
        }
        /* XXX breadcrumb */

        return 0;
}

static void cleanup_status_page(struct intel_ring_buffer *ring)
{
        drm_i915_private_t *dev_priv = ring->dev->dev_private;
        struct drm_gem_object *obj;
        struct drm_i915_gem_object *obj_priv;

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

        kunmap(obj_priv->pages[0]);
        i915_gem_object_unpin(obj);
        drm_gem_object_unreference(obj);
        ring->status_page.obj = NULL;

        memset(&dev_priv->hws_map, 0, sizeof(dev_priv->hws_map));
}

static int init_status_page(struct intel_ring_buffer *ring)
{
        struct drm_device *dev = ring->dev;
        drm_i915_private_t *dev_priv = dev->dev_private;
        struct drm_gem_object *obj;
        struct drm_i915_gem_object *obj_priv;
        int ret;

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

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

        ring->status_page.gfx_addr = obj_priv->gtt_offset;
        ring->status_page.page_addr = kmap(obj_priv->pages[0]);
        if (ring->status_page.page_addr == NULL) {
                memset(&dev_priv->hws_map, 0, sizeof(dev_priv->hws_map));
                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);
err:
        return ret;
}

int intel_init_ring_buffer(struct drm_device *dev,
                           struct intel_ring_buffer *ring)
{
        struct drm_i915_gem_object *obj_priv;
        struct drm_gem_object *obj;
        int ret;

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

        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->gem_object = obj;

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

        obj_priv = to_intel_bo(obj);
        ring->map.size = ring->size;
        ring->map.offset = dev->agp->base + obj_priv->gtt_offset;
        ring->map.type = 0;
        ring->map.flags = 0;
        ring->map.mtrr = 0;

        drm_core_ioremap_wc(&ring->map, dev);
        if (ring->map.handle == NULL) {
                DRM_ERROR("Failed to map ringbuffer.\n");
                ret = -EINVAL;
                goto err_unpin;
        }

        ring->virtual_start = ring->map.handle;
        ret = ring->init(ring);
        if (ret)
                goto err_unmap;

        return 0;

err_unmap:
        drm_core_ioremapfree(&ring->map, dev);
err_unpin:
        i915_gem_object_unpin(obj);
err_unref:
        drm_gem_object_unreference(obj);
        ring->gem_object = 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->gem_object == NULL)
                return;

        /* Disable the ring buffer. The ring must be idle at this point */
        dev_priv = ring->dev->dev_private;
        ret = intel_wait_ring_buffer(ring, ring->size - 8);
        I915_WRITE_CTL(ring, 0);

        drm_core_ioremapfree(&ring->map, ring->dev);

        i915_gem_object_unpin(ring->gem_object);
        drm_gem_object_unreference(ring->gem_object);
        ring->gem_object = NULL;

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

        cleanup_status_page(ring);
}

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

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

        virt = (unsigned int *)(ring->virtual_start + ring->tail);
        rem /= 8;
        while (rem--) {
                *virt++ = MI_NOOP;
                *virt++ = MI_NOOP;
        }

        ring->tail = 0;
        ring->space = ring->head - 8;

        return 0;
}

int intel_wait_ring_buffer(struct intel_ring_buffer *ring, int n)
{
        struct drm_device *dev = ring->dev;
        drm_i915_private_t *dev_priv = dev->dev_private;
        unsigned long end;
        u32 head;

        head = intel_read_status_page(ring, 4);
        if (head) {
                ring->head = head & HEAD_ADDR;
                ring->space = ring->head - (ring->tail + 8);
                if (ring->space < 0)
                        ring->space += ring->size;
                if (ring->space >= n)
                        return 0;
        }

        trace_i915_ring_wait_begin (dev);
        end = jiffies + 3 * HZ;
        do {
                ring->head = I915_READ_HEAD(ring) & HEAD_ADDR;
                ring->space = ring->head - (ring->tail + 8);
                if (ring->space < 0)
                        ring->space += ring->size;
                if (ring->space >= n) {
                        trace_i915_ring_wait_end(dev);
                        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);
                if (atomic_read(&dev_priv->mm.wedged))
                        return -EAGAIN;
        } while (!time_after(jiffies, end));
        trace_i915_ring_wait_end (dev);
        return -EBUSY;
}

int intel_ring_begin(struct intel_ring_buffer *ring,
                     int num_dwords)
{
        int n = 4*num_dwords;
        int ret;

        if (unlikely(ring->tail + n > ring->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)
{
        ring->tail &= ring->size - 1;
        ring->write_tail(ring, ring->tail);
}

static const struct intel_ring_buffer render_ring = {
        .name                   = "render ring",
        .id                     = RING_RENDER,
        .mmio_base              = RENDER_RING_BASE,
        .size                   = 32 * PAGE_SIZE,
        .init                   = init_render_ring,
        .write_tail             = ring_write_tail,
        .flush                  = render_ring_flush,
        .add_request            = render_ring_add_request,
        .get_seqno              = render_ring_get_seqno,
        .user_irq_get           = render_ring_get_user_irq,
        .user_irq_put           = render_ring_put_user_irq,
        .dispatch_execbuffer    = render_ring_dispatch_execbuffer,
};

/* ring buffer for bit-stream decoder */

static const struct intel_ring_buffer bsd_ring = {
        .name                   = "bsd ring",
        .id                     = RING_BSD,
        .mmio_base              = BSD_RING_BASE,
        .size                   = 32 * PAGE_SIZE,
        .init                   = init_ring_common,
        .write_tail             = ring_write_tail,
        .flush                  = bsd_ring_flush,
        .add_request            = ring_add_request,
        .get_seqno              = ring_status_page_get_seqno,
        .user_irq_get           = bsd_ring_get_user_irq,
        .user_irq_put           = bsd_ring_put_user_irq,
        .dispatch_execbuffer    = ring_dispatch_execbuffer,
};


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 */
       I915_WRITE(GEN6_BSD_SLEEP_PSMI_CONTROL,
               GEN6_BSD_SLEEP_PSMI_CONTROL_RC_ILDL_MESSAGE_MODIFY_MASK |
               GEN6_BSD_SLEEP_PSMI_CONTROL_RC_ILDL_MESSAGE_DISABLE);
       I915_WRITE(GEN6_BSD_RNCID, 0x0);

       if (wait_for((I915_READ(GEN6_BSD_SLEEP_PSMI_CONTROL) &
                               GEN6_BSD_SLEEP_PSMI_CONTROL_IDLE_INDICATOR) == 0,
                       50))
               DRM_ERROR("timed out waiting for IDLE Indicator\n");

       I915_WRITE_TAIL(ring, value);
       I915_WRITE(GEN6_BSD_SLEEP_PSMI_CONTROL,
               GEN6_BSD_SLEEP_PSMI_CONTROL_RC_ILDL_MESSAGE_MODIFY_MASK |
               GEN6_BSD_SLEEP_PSMI_CONTROL_RC_ILDL_MESSAGE_ENABLE);
}

static void gen6_ring_flush(struct intel_ring_buffer *ring,
                            u32 invalidate_domains,
                            u32 flush_domains)
{
        if (intel_ring_begin(ring, 4) == 0) {
                intel_ring_emit(ring, MI_FLUSH_DW);
                intel_ring_emit(ring, 0);
                intel_ring_emit(ring, 0);
                intel_ring_emit(ring, 0);
                intel_ring_advance(ring);
        }
}

static int
gen6_ring_dispatch_execbuffer(struct intel_ring_buffer *ring,
                              struct drm_i915_gem_execbuffer2 *exec,
                              struct drm_clip_rect *cliprects,
                              uint64_t exec_offset)
{
       uint32_t exec_start;
       int ret;

       exec_start = (uint32_t) exec_offset + exec->batch_start_offset;

       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, exec_start);
       intel_ring_advance(ring);

       return 0;
}

/* ring buffer for Video Codec for Gen6+ */
static const struct intel_ring_buffer gen6_bsd_ring = {
       .name                    = "gen6 bsd ring",
       .id                      = RING_BSD,
       .mmio_base               = GEN6_BSD_RING_BASE,
       .size                    = 32 * PAGE_SIZE,
       .init                    = init_ring_common,
       .write_tail              = gen6_bsd_ring_write_tail,
       .flush                   = gen6_ring_flush,
       .add_request             = ring_add_request,
       .get_seqno               = ring_status_page_get_seqno,
       .user_irq_get            = bsd_ring_get_user_irq,
       .user_irq_put            = bsd_ring_put_user_irq,
       .dispatch_execbuffer     = gen6_ring_dispatch_execbuffer,
};

/* Blitter support (SandyBridge+) */

static void
blt_ring_get_user_irq(struct intel_ring_buffer *ring)
{
        /* do nothing */
}
static void
blt_ring_put_user_irq(struct intel_ring_buffer *ring)
{
        /* do nothing */
}


/* Workaround for some stepping of SNB,
 * each time when BLT engine ring tail moved,
 * the first command in the ring to be parsed
 * should be MI_BATCH_BUFFER_START
 */
#define NEED_BLT_WORKAROUND(dev) \
        (IS_GEN6(dev) && (dev->pdev->revision < 8))

static inline struct drm_i915_gem_object *
to_blt_workaround(struct intel_ring_buffer *ring)
{
        return ring->private;
}

static int blt_ring_init(struct intel_ring_buffer *ring)
{
        if (NEED_BLT_WORKAROUND(ring->dev)) {
                struct drm_i915_gem_object *obj;
                u32 *ptr;
                int ret;

                obj = to_intel_bo(i915_gem_alloc_object(ring->dev, 4096));
                if (obj == NULL)
                        return -ENOMEM;

                ret = i915_gem_object_pin(&obj->base, 4096, true);
                if (ret) {
                        drm_gem_object_unreference(&obj->base);
                        return ret;
                }

                ptr = kmap(obj->pages[0]);
                *ptr++ = MI_BATCH_BUFFER_END;
                *ptr++ = MI_NOOP;
                kunmap(obj->pages[0]);

                ret = i915_gem_object_set_to_gtt_domain(&obj->base, false);
                if (ret) {
                        i915_gem_object_unpin(&obj->base);
                        drm_gem_object_unreference(&obj->base);
                        return ret;
                }

                ring->private = obj;
        }

        return init_ring_common(ring);
}

static int blt_ring_begin(struct intel_ring_buffer *ring,
                          int num_dwords)
{
        if (ring->private) {
                int ret = intel_ring_begin(ring, num_dwords+2);
                if (ret)
                        return ret;

                intel_ring_emit(ring, MI_BATCH_BUFFER_START);
                intel_ring_emit(ring, to_blt_workaround(ring)->gtt_offset);

                return 0;
        } else
                return intel_ring_begin(ring, 4);
}

static void blt_ring_flush(struct intel_ring_buffer *ring,
                           u32 invalidate_domains,
                           u32 flush_domains)
{
        if (blt_ring_begin(ring, 4) == 0) {
                intel_ring_emit(ring, MI_FLUSH_DW);
                intel_ring_emit(ring, 0);
                intel_ring_emit(ring, 0);
                intel_ring_emit(ring, 0);
                intel_ring_advance(ring);
        }
}

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

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

        seqno = i915_gem_get_seqno(ring->dev);

        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);

        DRM_DEBUG_DRIVER("%s %d\n", ring->name, seqno);
        *result = seqno;
        return 0;
}

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

        i915_gem_object_unpin(ring->private);
        drm_gem_object_unreference(ring->private);
        ring->private = NULL;
}

static const struct intel_ring_buffer gen6_blt_ring = {
       .name                    = "blt ring",
       .id                      = RING_BLT,
       .mmio_base               = BLT_RING_BASE,
       .size                    = 32 * PAGE_SIZE,
       .init                    = blt_ring_init,
       .write_tail              = ring_write_tail,
       .flush                   = blt_ring_flush,
       .add_request             = blt_ring_add_request,
       .get_seqno               = ring_status_page_get_seqno,
       .user_irq_get            = blt_ring_get_user_irq,
       .user_irq_put            = blt_ring_put_user_irq,
       .dispatch_execbuffer     = gen6_ring_dispatch_execbuffer,
       .cleanup                 = blt_ring_cleanup,
};

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

        dev_priv->render_ring = render_ring;

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

        return intel_init_ring_buffer(dev, &dev_priv->render_ring);
}

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

        if (IS_GEN6(dev))
                dev_priv->bsd_ring = gen6_bsd_ring;
        else
                dev_priv->bsd_ring = bsd_ring;

        return intel_init_ring_buffer(dev, &dev_priv->bsd_ring);
}

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

        dev_priv->blt_ring = gen6_blt_ring;

        return intel_init_ring_buffer(dev, &dev_priv->blt_ring);
}