blob: fc66af6a9448e0dc8013194ab032d793012dd1bd [file] [log] [blame]
/*
* 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"
/*
* 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
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 (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 (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 */
intel_emit_post_sync_nonzero_flush(ring);
/* Just flush everything. Experiments have shown that reducing the
* number of bits based on the write domains has little performance
* impact.
*/
flags |= PIPE_CONTROL_RENDER_TARGET_CACHE_FLUSH;
flags |= PIPE_CONTROL_INSTRUCTION_CACHE_INVALIDATE;
flags |= PIPE_CONTROL_TEXTURE_CACHE_INVALIDATE;
flags |= PIPE_CONTROL_DEPTH_CACHE_FLUSH;
flags |= PIPE_CONTROL_VF_CACHE_INVALIDATE;
flags |= PIPE_CONTROL_CONST_CACHE_INVALIDATE;
flags |= PIPE_CONTROL_STATE_CACHE_INVALIDATE;
ret = intel_ring_begin(ring, 6);
if (ret)
return ret;
intel_ring_emit(ring, GFX_OP_PIPE_CONTROL(5));
intel_ring_emit(ring, flags);
intel_ring_emit(ring, scratch_addr | PIPE_CONTROL_GLOBAL_GTT);
intel_ring_emit(ring, 0); /* lower dword */
intel_ring_emit(ring, 0); /* uppwer dword */
intel_ring_emit(ring, MI_NOOP);
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)
{
drm_i915_private_t *dev_priv = ring->dev->dev_private;
struct drm_i915_gem_object *obj = ring->obj;
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->gtt_offset);
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));
}
}
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 ((I915_READ_CTL(ring) & RING_VALID) == 0 ||
I915_READ_START(ring) != obj->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);
ring->tail = I915_READ_TAIL(ring) & TAIL_ADDR;
ring->space = ring_space(ring);
}
return 0;
}
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);
if (ret)
goto err_unref;
pc->gtt_offset = obj->gtt_offset;
pc->cpu_page = kmap(obj->pages[0]);
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(obj->pages[0]);
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) {
int mode = VS_TIMER_DISPATCH << 16 | VS_TIMER_DISPATCH;
I915_WRITE(MI_MODE, mode);
if (IS_GEN7(dev))
I915_WRITE(GFX_MODE_GEN7,
GFX_MODE_DISABLE(GFX_TLB_INVALIDATE_ALWAYS) |
GFX_MODE_ENABLE(GFX_REPLAY_MODE));
}
if (INTEL_INFO(dev)->gen >= 5) {
ret = init_pipe_control(ring);
if (ret)
return ret;
}
if (INTEL_INFO(dev)->gen >= 6) {
I915_WRITE(INSTPM,
INSTPM_FORCE_ORDERING << 16 | INSTPM_FORCE_ORDERING);
}
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
intel_ring_sync(struct intel_ring_buffer *waiter,
struct intel_ring_buffer *signaller,
int ring,
u32 seqno)
{
int ret;
u32 dw1 = MI_SEMAPHORE_MBOX |
MI_SEMAPHORE_COMPARE |
MI_SEMAPHORE_REGISTER;
ret = intel_ring_begin(waiter, 4);
if (ret)
return ret;
intel_ring_emit(waiter, dw1 | signaller->semaphore_register[ring]);
intel_ring_emit(waiter, seqno);
intel_ring_emit(waiter, 0);
intel_ring_emit(waiter, MI_NOOP);
intel_ring_advance(waiter);
return 0;
}
/* VCS->RCS (RVSYNC) or BCS->RCS (RBSYNC) */
int
render_ring_sync_to(struct intel_ring_buffer *waiter,
struct intel_ring_buffer *signaller,
u32 seqno)
{
WARN_ON(signaller->semaphore_register[RCS] == MI_SEMAPHORE_SYNC_INVALID);
return intel_ring_sync(waiter,
signaller,
RCS,
seqno);
}
/* RCS->VCS (VRSYNC) or BCS->VCS (VBSYNC) */
int
gen6_bsd_ring_sync_to(struct intel_ring_buffer *waiter,
struct intel_ring_buffer *signaller,
u32 seqno)
{
WARN_ON(signaller->semaphore_register[VCS] == MI_SEMAPHORE_SYNC_INVALID);
return intel_ring_sync(waiter,
signaller,
VCS,
seqno);
}
/* RCS->BCS (BRSYNC) or VCS->BCS (BVSYNC) */
int
gen6_blt_ring_sync_to(struct intel_ring_buffer *waiter,
struct intel_ring_buffer *signaller,
u32 seqno)
{
WARN_ON(signaller->semaphore_register[BCS] == MI_SEMAPHORE_SYNC_INVALID);
return intel_ring_sync(waiter,
signaller,
BCS,
seqno);
}
#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 int
render_ring_add_request(struct intel_ring_buffer *ring,
u32 *result)
{
u32 seqno = i915_gem_next_request_seqno(ring);
int ret;
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
gen6_ring_get_seqno(struct intel_ring_buffer *ring)
{
struct drm_device *dev = ring->dev;
/* 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 (IS_GEN7(dev))
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)
{
return intel_read_status_page(ring, I915_GEM_HWS_INDEX);
}
static u32
pc_render_get_seqno(struct intel_ring_buffer *ring)
{
struct pipe_control *pc = ring->private;
return pc->cpu_page[0];
}
static void
ironlake_enable_irq(drm_i915_private_t *dev_priv, u32 mask)
{
dev_priv->gt_irq_mask &= ~mask;
I915_WRITE(GTIMR, dev_priv->gt_irq_mask);
POSTING_READ(GTIMR);
}
static void
ironlake_disable_irq(drm_i915_private_t *dev_priv, u32 mask)
{
dev_priv->gt_irq_mask |= mask;
I915_WRITE(GTIMR, dev_priv->gt_irq_mask);
POSTING_READ(GTIMR);
}
static void
i915_enable_irq(drm_i915_private_t *dev_priv, u32 mask)
{
dev_priv->irq_mask &= ~mask;
I915_WRITE(IMR, dev_priv->irq_mask);
POSTING_READ(IMR);
}
static void
i915_disable_irq(drm_i915_private_t *dev_priv, u32 mask)
{
dev_priv->irq_mask |= mask;
I915_WRITE(IMR, dev_priv->irq_mask);
POSTING_READ(IMR);
}
static bool
render_ring_get_irq(struct intel_ring_buffer *ring)
{
struct drm_device *dev = ring->dev;
drm_i915_private_t *dev_priv = dev->dev_private;
if (!dev->irq_enabled)
return false;
spin_lock(&ring->irq_lock);
if (ring->irq_refcount++ == 0) {
if (HAS_PCH_SPLIT(dev))
ironlake_enable_irq(dev_priv,
GT_PIPE_NOTIFY | GT_USER_INTERRUPT);
else
i915_enable_irq(dev_priv, I915_USER_INTERRUPT);
}
spin_unlock(&ring->irq_lock);
return true;
}
static void
render_ring_put_irq(struct intel_ring_buffer *ring)
{
struct drm_device *dev = ring->dev;
drm_i915_private_t *dev_priv = dev->dev_private;
spin_lock(&ring->irq_lock);
if (--ring->irq_refcount == 0) {
if (HAS_PCH_SPLIT(dev))
ironlake_disable_irq(dev_priv,
GT_USER_INTERRUPT |
GT_PIPE_NOTIFY);
else
i915_disable_irq(dev_priv, I915_USER_INTERRUPT);
}
spin_unlock(&ring->irq_lock);
}
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
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_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, u32 gflag, u32 rflag)
{
struct drm_device *dev = ring->dev;
drm_i915_private_t *dev_priv = dev->dev_private;
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(&ring->irq_lock);
if (ring->irq_refcount++ == 0) {
ring->irq_mask &= ~rflag;
I915_WRITE_IMR(ring, ring->irq_mask);
ironlake_enable_irq(dev_priv, gflag);
}
spin_unlock(&ring->irq_lock);
return true;
}
static void
gen6_ring_put_irq(struct intel_ring_buffer *ring, u32 gflag, u32 rflag)
{
struct drm_device *dev = ring->dev;
drm_i915_private_t *dev_priv = dev->dev_private;
spin_lock(&ring->irq_lock);
if (--ring->irq_refcount == 0) {
ring->irq_mask |= rflag;
I915_WRITE_IMR(ring, ring->irq_mask);
ironlake_disable_irq(dev_priv, gflag);
}
spin_unlock(&ring->irq_lock);
gen6_gt_force_wake_put(dev_priv);
}
static bool
bsd_ring_get_irq(struct intel_ring_buffer *ring)
{
struct drm_device *dev = ring->dev;
drm_i915_private_t *dev_priv = dev->dev_private;
if (!dev->irq_enabled)
return false;
spin_lock(&ring->irq_lock);
if (ring->irq_refcount++ == 0) {
if (IS_G4X(dev))
i915_enable_irq(dev_priv, I915_BSD_USER_INTERRUPT);
else
ironlake_enable_irq(dev_priv, GT_BSD_USER_INTERRUPT);
}
spin_unlock(&ring->irq_lock);
return true;
}
static void
bsd_ring_put_irq(struct intel_ring_buffer *ring)
{
struct drm_device *dev = ring->dev;
drm_i915_private_t *dev_priv = dev->dev_private;
spin_lock(&ring->irq_lock);
if (--ring->irq_refcount == 0) {
if (IS_G4X(dev))
i915_disable_irq(dev_priv, I915_BSD_USER_INTERRUPT);
else
ironlake_disable_irq(dev_priv, GT_BSD_USER_INTERRUPT);
}
spin_unlock(&ring->irq_lock);
}
static int
ring_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 | (2 << 6) |
MI_BATCH_NON_SECURE_I965);
intel_ring_emit(ring, offset);
intel_ring_advance(ring);
return 0;
}
static int
render_ring_dispatch_execbuffer(struct intel_ring_buffer *ring,
u32 offset, u32 len)
{
struct drm_device *dev = ring->dev;
int 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, offset | MI_BATCH_NON_SECURE);
intel_ring_emit(ring, offset + len - 8);
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, offset);
} else {
intel_ring_emit(ring,
MI_BATCH_BUFFER_START | (2 << 6));
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)
{
drm_i915_private_t *dev_priv = ring->dev->dev_private;
struct drm_i915_gem_object *obj;
obj = ring->status_page.obj;
if (obj == NULL)
return;
kunmap(obj->pages[0]);
i915_gem_object_unpin(obj);
drm_gem_object_unreference(&obj->base);
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_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);
if (ret != 0) {
goto err_unref;
}
ring->status_page.gfx_addr = obj->gtt_offset;
ring->status_page.page_addr = kmap(obj->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->base);
err:
return ret;
}
int intel_init_ring_buffer(struct drm_device *dev,
struct intel_ring_buffer *ring)
{
struct drm_i915_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);
init_waitqueue_head(&ring->irq_queue);
spin_lock_init(&ring->irq_lock);
ring->irq_mask = ~0;
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);
if (ret)
goto err_unref;
ring->map.size = ring->size;
ring->map.offset = dev->agp->base + obj->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;
/* 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))
ring->effective_size -= 128;
return 0;
err_unmap:
drm_core_ioremapfree(&ring->map, dev);
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);
drm_core_ioremapfree(&ring->map, ring->dev);
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)
{
unsigned int *virt;
int 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_space(ring);
return 0;
}
static int intel_ring_wait_seqno(struct intel_ring_buffer *ring, u32 seqno)
{
struct drm_i915_private *dev_priv = ring->dev->dev_private;
bool was_interruptible;
int ret;
/* XXX As we have not yet audited all the paths to check that
* they are ready for ERESTARTSYS from intel_ring_begin, do not
* allow us to be interruptible by a signal.
*/
was_interruptible = dev_priv->mm.interruptible;
dev_priv->mm.interruptible = false;
ret = i915_wait_request(ring, seqno, true);
dev_priv->mm.interruptible = was_interruptible;
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);
if (drm_core_check_feature(dev, DRIVER_GEM))
/* 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;
else
end = jiffies + 3 * 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);
if (atomic_read(&dev_priv->mm.wedged))
return -EAGAIN;
} 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)
{
struct drm_i915_private *dev_priv = ring->dev->dev_private;
int n = 4*num_dwords;
int ret;
if (unlikely(atomic_read(&dev_priv->mm.wedged)))
return -EIO;
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)
{
ring->tail &= ring->size - 1;
ring->write_tail(ring, ring->tail);
}
static const struct intel_ring_buffer render_ring = {
.name = "render ring",
.id = RCS,
.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 = ring_get_seqno,
.irq_get = render_ring_get_irq,
.irq_put = render_ring_put_irq,
.dispatch_execbuffer = render_ring_dispatch_execbuffer,
.cleanup = render_ring_cleanup,
.sync_to = render_ring_sync_to,
.semaphore_register = {MI_SEMAPHORE_SYNC_INVALID,
MI_SEMAPHORE_SYNC_RV,
MI_SEMAPHORE_SYNC_RB},
.signal_mbox = {GEN6_VRSYNC, GEN6_BRSYNC},
};
/* ring buffer for bit-stream decoder */
static const struct intel_ring_buffer bsd_ring = {
.name = "bsd ring",
.id = VCS,
.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_get_seqno,
.irq_get = bsd_ring_get_irq,
.irq_put = bsd_ring_put_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 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;
}
static bool
gen6_render_ring_get_irq(struct intel_ring_buffer *ring)
{
return gen6_ring_get_irq(ring,
GT_USER_INTERRUPT,
GEN6_RENDER_USER_INTERRUPT);
}
static void
gen6_render_ring_put_irq(struct intel_ring_buffer *ring)
{
return gen6_ring_put_irq(ring,
GT_USER_INTERRUPT,
GEN6_RENDER_USER_INTERRUPT);
}
static bool
gen6_bsd_ring_get_irq(struct intel_ring_buffer *ring)
{
return gen6_ring_get_irq(ring,
GT_GEN6_BSD_USER_INTERRUPT,
GEN6_BSD_USER_INTERRUPT);
}
static void
gen6_bsd_ring_put_irq(struct intel_ring_buffer *ring)
{
return gen6_ring_put_irq(ring,
GT_GEN6_BSD_USER_INTERRUPT,
GEN6_BSD_USER_INTERRUPT);
}
/* ring buffer for Video Codec for Gen6+ */
static const struct intel_ring_buffer gen6_bsd_ring = {
.name = "gen6 bsd ring",
.id = VCS,
.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 = gen6_add_request,
.get_seqno = gen6_ring_get_seqno,
.irq_get = gen6_bsd_ring_get_irq,
.irq_put = gen6_bsd_ring_put_irq,
.dispatch_execbuffer = gen6_ring_dispatch_execbuffer,
.sync_to = gen6_bsd_ring_sync_to,
.semaphore_register = {MI_SEMAPHORE_SYNC_VR,
MI_SEMAPHORE_SYNC_INVALID,
MI_SEMAPHORE_SYNC_VB},
.signal_mbox = {GEN6_RVSYNC, GEN6_BVSYNC},
};
/* Blitter support (SandyBridge+) */
static bool
blt_ring_get_irq(struct intel_ring_buffer *ring)
{
return gen6_ring_get_irq(ring,
GT_BLT_USER_INTERRUPT,
GEN6_BLITTER_USER_INTERRUPT);
}
static void
blt_ring_put_irq(struct intel_ring_buffer *ring)
{
gen6_ring_put_irq(ring,
GT_BLT_USER_INTERRUPT,
GEN6_BLITTER_USER_INTERRUPT);
}
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;
}
static const struct intel_ring_buffer gen6_blt_ring = {
.name = "blt ring",
.id = BCS,
.mmio_base = BLT_RING_BASE,
.size = 32 * PAGE_SIZE,
.init = init_ring_common,
.write_tail = ring_write_tail,
.flush = blt_ring_flush,
.add_request = gen6_add_request,
.get_seqno = gen6_ring_get_seqno,
.irq_get = blt_ring_get_irq,
.irq_put = blt_ring_put_irq,
.dispatch_execbuffer = gen6_ring_dispatch_execbuffer,
.sync_to = gen6_blt_ring_sync_to,
.semaphore_register = {MI_SEMAPHORE_SYNC_BR,
MI_SEMAPHORE_SYNC_BV,
MI_SEMAPHORE_SYNC_INVALID},
.signal_mbox = {GEN6_RBSYNC, GEN6_VBSYNC},
};
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 = render_ring;
if (INTEL_INFO(dev)->gen >= 6) {
ring->add_request = gen6_add_request;
ring->flush = gen6_render_ring_flush;
ring->irq_get = gen6_render_ring_get_irq;
ring->irq_put = gen6_render_ring_put_irq;
ring->get_seqno = gen6_ring_get_seqno;
} else if (IS_GEN5(dev)) {
ring->add_request = pc_render_add_request;
ring->get_seqno = pc_render_get_seqno;
}
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 = render_ring;
if (INTEL_INFO(dev)->gen >= 6) {
ring->add_request = gen6_add_request;
ring->irq_get = gen6_render_ring_get_irq;
ring->irq_put = gen6_render_ring_put_irq;
} else if (IS_GEN5(dev)) {
ring->add_request = pc_render_add_request;
ring->get_seqno = pc_render_get_seqno;
}
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);
INIT_LIST_HEAD(&ring->gpu_write_list);
ring->size = size;
ring->effective_size = ring->size;
if (IS_I830(ring->dev))
ring->effective_size -= 128;
ring->map.offset = start;
ring->map.size = size;
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("can not ioremap virtual address for"
" ring buffer\n");
return -ENOMEM;
}
ring->virtual_start = (void __force __iomem *)ring->map.handle;
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];
if (IS_GEN6(dev) || IS_GEN7(dev))
*ring = gen6_bsd_ring;
else
*ring = bsd_ring;
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 = gen6_blt_ring;
return intel_init_ring_buffer(dev, ring);
}