Skip to content
Snippets Groups Projects
Select Git revision
  • 95f697eb024d7def7f9050cd5eba9502034dd94d
  • vme-testing default
  • ci-test
  • master
  • remoteproc
  • am625-sk-ov5640
  • pcal6534-upstreaming
  • lps22df-upstreaming
  • msc-upstreaming
  • imx8mp
  • iio/noa1305
  • vme-next
  • vme-next-4.14-rc4
  • v4.14-rc4
  • v4.14-rc3
  • v4.14-rc2
  • v4.14-rc1
  • v4.13
  • vme-next-4.13-rc7
  • v4.13-rc7
  • v4.13-rc6
  • v4.13-rc5
  • v4.13-rc4
  • v4.13-rc3
  • v4.13-rc2
  • v4.13-rc1
  • v4.12
  • v4.12-rc7
  • v4.12-rc6
  • v4.12-rc5
  • v4.12-rc4
  • v4.12-rc3
32 results

intel_ringbuffer.c

Blame
  • intel_ringbuffer.c 60.46 KiB
    /*
     * 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 <linux/log2.h>
    
    #include <drm/i915_drm.h>
    
    #include "i915_drv.h"
    #include "i915_gem_render_state.h"
    #include "i915_reset.h"
    #include "i915_trace.h"
    #include "intel_drv.h"
    #include "intel_workarounds.h"
    
    /* Rough estimate of the typical request size, performing a flush,
     * set-context and then emitting the batch.
     */
    #define LEGACY_REQUEST_SIZE 200
    
    static inline u32 hws_hangcheck_address(struct intel_engine_cs *engine)
    {
    	return (i915_ggtt_offset(engine->status_page.vma) +
    		I915_GEM_HWS_HANGCHECK_ADDR);
    }
    
    unsigned int intel_ring_update_space(struct intel_ring *ring)
    {
    	unsigned int space;
    
    	space = __intel_ring_space(ring->head, ring->emit, ring->size);
    
    	ring->space = space;
    	return space;
    }
    
    static int
    gen2_render_ring_flush(struct i915_request *rq, u32 mode)
    {
    	unsigned int num_store_dw;
    	u32 cmd, *cs;
    
    	cmd = MI_FLUSH;
    	num_store_dw = 0;
    	if (mode & EMIT_INVALIDATE)
    		cmd |= MI_READ_FLUSH;
    	if (mode & EMIT_FLUSH)
    		num_store_dw = 4;
    
    	cs = intel_ring_begin(rq, 2 + 3 * num_store_dw);
    	if (IS_ERR(cs))
    		return PTR_ERR(cs);
    
    	*cs++ = cmd;
    	while (num_store_dw--) {
    		*cs++ = MI_STORE_DWORD_IMM | MI_MEM_VIRTUAL;
    		*cs++ = i915_scratch_offset(rq->i915);
    		*cs++ = 0;
    	}
    	*cs++ = MI_FLUSH | MI_NO_WRITE_FLUSH;
    
    	intel_ring_advance(rq, cs);
    
    	return 0;
    }
    
    static int
    gen4_render_ring_flush(struct i915_request *rq, u32 mode)
    {
    	u32 cmd, *cs;
    	int i;
    
    	/*
    	 * 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;
    	if (mode & EMIT_INVALIDATE) {
    		cmd |= MI_EXE_FLUSH;
    		if (IS_G4X(rq->i915) || IS_GEN(rq->i915, 5))
    			cmd |= MI_INVALIDATE_ISP;
    	}
    
    	i = 2;
    	if (mode & EMIT_INVALIDATE)
    		i += 20;
    
    	cs = intel_ring_begin(rq, i);
    	if (IS_ERR(cs))
    		return PTR_ERR(cs);
    
    	*cs++ = cmd;
    
    	/*
    	 * A random delay to let the CS invalidate take effect? Without this
    	 * delay, the GPU relocation path fails as the CS does not see
    	 * the updated contents. Just as important, if we apply the flushes
    	 * to the EMIT_FLUSH branch (i.e. immediately after the relocation
    	 * write and before the invalidate on the next batch), the relocations
    	 * still fail. This implies that is a delay following invalidation
    	 * that is required to reset the caches as opposed to a delay to
    	 * ensure the memory is written.
    	 */
    	if (mode & EMIT_INVALIDATE) {
    		*cs++ = GFX_OP_PIPE_CONTROL(4) | PIPE_CONTROL_QW_WRITE;
    		*cs++ = i915_scratch_offset(rq->i915) | PIPE_CONTROL_GLOBAL_GTT;
    		*cs++ = 0;
    		*cs++ = 0;
    
    		for (i = 0; i < 12; i++)
    			*cs++ = MI_FLUSH;
    
    		*cs++ = GFX_OP_PIPE_CONTROL(4) | PIPE_CONTROL_QW_WRITE;
    		*cs++ = i915_scratch_offset(rq->i915) | PIPE_CONTROL_GLOBAL_GTT;
    		*cs++ = 0;
    		*cs++ = 0;
    	}
    
    	*cs++ = cmd;
    
    	intel_ring_advance(rq, cs);
    
    	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
    gen6_emit_post_sync_nonzero_flush(struct i915_request *rq)
    {
    	u32 scratch_addr = i915_scratch_offset(rq->i915) + 2 * CACHELINE_BYTES;
    	u32 *cs;
    
    	cs = intel_ring_begin(rq, 6);
    	if (IS_ERR(cs))
    		return PTR_ERR(cs);
    
    	*cs++ = GFX_OP_PIPE_CONTROL(5);
    	*cs++ = PIPE_CONTROL_CS_STALL | PIPE_CONTROL_STALL_AT_SCOREBOARD;
    	*cs++ = scratch_addr | PIPE_CONTROL_GLOBAL_GTT;
    	*cs++ = 0; /* low dword */
    	*cs++ = 0; /* high dword */
    	*cs++ = MI_NOOP;
    	intel_ring_advance(rq, cs);
    
    	cs = intel_ring_begin(rq, 6);
    	if (IS_ERR(cs))
    		return PTR_ERR(cs);
    
    	*cs++ = GFX_OP_PIPE_CONTROL(5);
    	*cs++ = PIPE_CONTROL_QW_WRITE;
    	*cs++ = scratch_addr | PIPE_CONTROL_GLOBAL_GTT;
    	*cs++ = 0;
    	*cs++ = 0;
    	*cs++ = MI_NOOP;
    	intel_ring_advance(rq, cs);
    
    	return 0;
    }
    
    static int
    gen6_render_ring_flush(struct i915_request *rq, u32 mode)
    {
    	u32 scratch_addr = i915_scratch_offset(rq->i915) + 2 * CACHELINE_BYTES;
    	u32 *cs, flags = 0;
    	int ret;
    
    	/* Force SNB workarounds for PIPE_CONTROL flushes */
    	ret = gen6_emit_post_sync_nonzero_flush(rq);
    	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 (mode & EMIT_FLUSH) {
    		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 (mode & EMIT_INVALIDATE) {
    		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 | PIPE_CONTROL_CS_STALL;
    	}
    
    	cs = intel_ring_begin(rq, 4);
    	if (IS_ERR(cs))
    		return PTR_ERR(cs);
    
    	*cs++ = GFX_OP_PIPE_CONTROL(4);
    	*cs++ = flags;
    	*cs++ = scratch_addr | PIPE_CONTROL_GLOBAL_GTT;
    	*cs++ = 0;
    	intel_ring_advance(rq, cs);
    
    	return 0;
    }
    
    static u32 *gen6_rcs_emit_breadcrumb(struct i915_request *rq, u32 *cs)
    {
    	/* First we do the gen6_emit_post_sync_nonzero_flush w/a */
    	*cs++ = GFX_OP_PIPE_CONTROL(4);
    	*cs++ = PIPE_CONTROL_CS_STALL | PIPE_CONTROL_STALL_AT_SCOREBOARD;
    	*cs++ = 0;
    	*cs++ = 0;
    
    	*cs++ = GFX_OP_PIPE_CONTROL(4);
    	*cs++ = PIPE_CONTROL_QW_WRITE;
    	*cs++ = i915_scratch_offset(rq->i915) | PIPE_CONTROL_GLOBAL_GTT;
    	*cs++ = 0;
    
    	/* Finally we can flush and with it emit the breadcrumb */
    	*cs++ = GFX_OP_PIPE_CONTROL(4);
    	*cs++ = (PIPE_CONTROL_RENDER_TARGET_CACHE_FLUSH |
    		 PIPE_CONTROL_DEPTH_CACHE_FLUSH |
    		 PIPE_CONTROL_DC_FLUSH_ENABLE |
    		 PIPE_CONTROL_QW_WRITE |
    		 PIPE_CONTROL_CS_STALL);
    	*cs++ = rq->timeline->hwsp_offset | PIPE_CONTROL_GLOBAL_GTT;
    	*cs++ = rq->fence.seqno;
    
    	*cs++ = GFX_OP_PIPE_CONTROL(4);
    	*cs++ = PIPE_CONTROL_QW_WRITE;
    	*cs++ = hws_hangcheck_address(rq->engine) | PIPE_CONTROL_GLOBAL_GTT;
    	*cs++ = intel_engine_next_hangcheck_seqno(rq->engine);
    
    	*cs++ = MI_USER_INTERRUPT;
    	*cs++ = MI_NOOP;
    
    	rq->tail = intel_ring_offset(rq, cs);
    	assert_ring_tail_valid(rq->ring, rq->tail);
    
    	return cs;
    }
    
    static int
    gen7_render_ring_cs_stall_wa(struct i915_request *rq)
    {
    	u32 *cs;
    
    	cs = intel_ring_begin(rq, 4);
    	if (IS_ERR(cs))
    		return PTR_ERR(cs);
    
    	*cs++ = GFX_OP_PIPE_CONTROL(4);
    	*cs++ = PIPE_CONTROL_CS_STALL | PIPE_CONTROL_STALL_AT_SCOREBOARD;
    	*cs++ = 0;
    	*cs++ = 0;
    	intel_ring_advance(rq, cs);
    
    	return 0;
    }
    
    static int
    gen7_render_ring_flush(struct i915_request *rq, u32 mode)
    {
    	u32 scratch_addr = i915_scratch_offset(rq->i915) + 2 * CACHELINE_BYTES;
    	u32 *cs, flags = 0;
    
    	/*
    	 * 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 (mode & EMIT_FLUSH) {
    		flags |= PIPE_CONTROL_RENDER_TARGET_CACHE_FLUSH;
    		flags |= PIPE_CONTROL_DEPTH_CACHE_FLUSH;
    		flags |= PIPE_CONTROL_DC_FLUSH_ENABLE;
    		flags |= PIPE_CONTROL_FLUSH_ENABLE;
    	}
    	if (mode & EMIT_INVALIDATE) {
    		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;
    		flags |= PIPE_CONTROL_MEDIA_STATE_CLEAR;
    		/*
    		 * TLB invalidate requires a post-sync write.
    		 */
    		flags |= PIPE_CONTROL_QW_WRITE;
    		flags |= PIPE_CONTROL_GLOBAL_GTT_IVB;
    
    		flags |= PIPE_CONTROL_STALL_AT_SCOREBOARD;
    
    		/* 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(rq);
    	}
    
    	cs = intel_ring_begin(rq, 4);
    	if (IS_ERR(cs))
    		return PTR_ERR(cs);
    
    	*cs++ = GFX_OP_PIPE_CONTROL(4);
    	*cs++ = flags;
    	*cs++ = scratch_addr;
    	*cs++ = 0;
    	intel_ring_advance(rq, cs);
    
    	return 0;
    }
    
    static u32 *gen7_rcs_emit_breadcrumb(struct i915_request *rq, u32 *cs)
    {
    	*cs++ = GFX_OP_PIPE_CONTROL(4);
    	*cs++ = (PIPE_CONTROL_RENDER_TARGET_CACHE_FLUSH |
    		 PIPE_CONTROL_DEPTH_CACHE_FLUSH |
    		 PIPE_CONTROL_DC_FLUSH_ENABLE |
    		 PIPE_CONTROL_FLUSH_ENABLE |
    		 PIPE_CONTROL_QW_WRITE |
    		 PIPE_CONTROL_GLOBAL_GTT_IVB |
    		 PIPE_CONTROL_CS_STALL);
    	*cs++ = rq->timeline->hwsp_offset;
    	*cs++ = rq->fence.seqno;
    
    	*cs++ = GFX_OP_PIPE_CONTROL(4);
    	*cs++ = PIPE_CONTROL_QW_WRITE | PIPE_CONTROL_GLOBAL_GTT_IVB;
    	*cs++ = hws_hangcheck_address(rq->engine);
    	*cs++ = intel_engine_next_hangcheck_seqno(rq->engine);
    
    	*cs++ = MI_USER_INTERRUPT;
    	*cs++ = MI_NOOP;
    
    	rq->tail = intel_ring_offset(rq, cs);
    	assert_ring_tail_valid(rq->ring, rq->tail);
    
    	return cs;
    }
    
    static u32 *gen6_xcs_emit_breadcrumb(struct i915_request *rq, u32 *cs)
    {
    	GEM_BUG_ON(rq->timeline->hwsp_ggtt != rq->engine->status_page.vma);
    	GEM_BUG_ON(offset_in_page(rq->timeline->hwsp_offset) != I915_GEM_HWS_SEQNO_ADDR);
    
    	*cs++ = MI_FLUSH_DW | MI_FLUSH_DW_OP_STOREDW | MI_FLUSH_DW_STORE_INDEX;
    	*cs++ = I915_GEM_HWS_SEQNO_ADDR | MI_FLUSH_DW_USE_GTT;
    	*cs++ = rq->fence.seqno;
    
    	*cs++ = MI_FLUSH_DW | MI_FLUSH_DW_OP_STOREDW | MI_FLUSH_DW_STORE_INDEX;
    	*cs++ = I915_GEM_HWS_HANGCHECK_ADDR | MI_FLUSH_DW_USE_GTT;
    	*cs++ = intel_engine_next_hangcheck_seqno(rq->engine);
    
    	*cs++ = MI_USER_INTERRUPT;
    	*cs++ = MI_NOOP;
    
    	rq->tail = intel_ring_offset(rq, cs);
    	assert_ring_tail_valid(rq->ring, rq->tail);
    
    	return cs;
    }
    
    #define GEN7_XCS_WA 32
    static u32 *gen7_xcs_emit_breadcrumb(struct i915_request *rq, u32 *cs)
    {
    	int i;
    
    	GEM_BUG_ON(rq->timeline->hwsp_ggtt != rq->engine->status_page.vma);
    	GEM_BUG_ON(offset_in_page(rq->timeline->hwsp_offset) != I915_GEM_HWS_SEQNO_ADDR);
    
    	*cs++ = MI_FLUSH_DW | MI_FLUSH_DW_OP_STOREDW | MI_FLUSH_DW_STORE_INDEX;
    	*cs++ = I915_GEM_HWS_SEQNO_ADDR | MI_FLUSH_DW_USE_GTT;
    	*cs++ = rq->fence.seqno;
    
    	*cs++ = MI_FLUSH_DW | MI_FLUSH_DW_OP_STOREDW | MI_FLUSH_DW_STORE_INDEX;
    	*cs++ = I915_GEM_HWS_HANGCHECK_ADDR | MI_FLUSH_DW_USE_GTT;
    	*cs++ = intel_engine_next_hangcheck_seqno(rq->engine);
    
    	for (i = 0; i < GEN7_XCS_WA; i++) {
    		*cs++ = MI_STORE_DWORD_INDEX;
    		*cs++ = I915_GEM_HWS_SEQNO_ADDR;
    		*cs++ = rq->fence.seqno;
    	}
    
    	*cs++ = MI_FLUSH_DW;
    	*cs++ = 0;
    	*cs++ = 0;
    
    	*cs++ = MI_USER_INTERRUPT;
    
    	rq->tail = intel_ring_offset(rq, cs);
    	assert_ring_tail_valid(rq->ring, rq->tail);
    
    	return cs;
    }
    #undef GEN7_XCS_WA
    
    static void set_hwstam(struct intel_engine_cs *engine, u32 mask)
    {
    	/*
    	 * Keep the render interrupt unmasked as this papers over
    	 * lost interrupts following a reset.
    	 */
    	if (engine->class == RENDER_CLASS) {
    		if (INTEL_GEN(engine->i915) >= 6)
    			mask &= ~BIT(0);
    		else
    			mask &= ~I915_USER_INTERRUPT;
    	}
    
    	intel_engine_set_hwsp_writemask(engine, mask);
    }
    
    static void set_hws_pga(struct intel_engine_cs *engine, phys_addr_t phys)
    {
    	struct drm_i915_private *dev_priv = engine->i915;
    	u32 addr;
    
    	addr = lower_32_bits(phys);
    	if (INTEL_GEN(dev_priv) >= 4)
    		addr |= (phys >> 28) & 0xf0;
    
    	I915_WRITE(HWS_PGA, addr);
    }
    
    static struct page *status_page(struct intel_engine_cs *engine)
    {
    	struct drm_i915_gem_object *obj = engine->status_page.vma->obj;
    
    	GEM_BUG_ON(!i915_gem_object_has_pinned_pages(obj));
    	return sg_page(obj->mm.pages->sgl);
    }
    
    static void ring_setup_phys_status_page(struct intel_engine_cs *engine)
    {
    	set_hws_pga(engine, PFN_PHYS(page_to_pfn(status_page(engine))));
    	set_hwstam(engine, ~0u);
    }
    
    static void set_hwsp(struct intel_engine_cs *engine, u32 offset)
    {
    	struct drm_i915_private *dev_priv = engine->i915;
    	i915_reg_t hwsp;
    
    	/*
    	 * The ring status page addresses are no longer next to the rest of
    	 * the ring registers as of gen7.
    	 */
    	if (IS_GEN(dev_priv, 7)) {
    		switch (engine->id) {
    		/*
    		 * No more rings exist on Gen7. Default case is only to shut up
    		 * gcc switch check warning.
    		 */
    		default:
    			GEM_BUG_ON(engine->id);
    			/* fallthrough */
    		case RCS0:
    			hwsp = RENDER_HWS_PGA_GEN7;
    			break;
    		case BCS0:
    			hwsp = BLT_HWS_PGA_GEN7;
    			break;
    		case VCS0:
    			hwsp = BSD_HWS_PGA_GEN7;
    			break;
    		case VECS0:
    			hwsp = VEBOX_HWS_PGA_GEN7;
    			break;
    		}
    	} else if (IS_GEN(dev_priv, 6)) {
    		hwsp = RING_HWS_PGA_GEN6(engine->mmio_base);
    	} else {
    		hwsp = RING_HWS_PGA(engine->mmio_base);
    	}
    
    	I915_WRITE(hwsp, offset);
    	POSTING_READ(hwsp);
    }
    
    static void flush_cs_tlb(struct intel_engine_cs *engine)
    {
    	struct drm_i915_private *dev_priv = engine->i915;
    	i915_reg_t instpm = RING_INSTPM(engine->mmio_base);
    
    	if (!IS_GEN_RANGE(dev_priv, 6, 7))
    		return;
    
    	/* ring should be idle before issuing a sync flush*/
    	WARN_ON((I915_READ_MODE(engine) & MODE_IDLE) == 0);
    
    	I915_WRITE(instpm,
    		   _MASKED_BIT_ENABLE(INSTPM_TLB_INVALIDATE |
    				      INSTPM_SYNC_FLUSH));
    	if (intel_wait_for_register(dev_priv,
    				    instpm, INSTPM_SYNC_FLUSH, 0,
    				    1000))
    		DRM_ERROR("%s: wait for SyncFlush to complete for TLB invalidation timed out\n",
    			  engine->name);
    }
    
    static void ring_setup_status_page(struct intel_engine_cs *engine)
    {
    	set_hwsp(engine, i915_ggtt_offset(engine->status_page.vma));
    	set_hwstam(engine, ~0u);
    
    	flush_cs_tlb(engine);
    }
    
    static bool stop_ring(struct intel_engine_cs *engine)
    {
    	struct drm_i915_private *dev_priv = engine->i915;
    
    	if (INTEL_GEN(dev_priv) > 2) {
    		I915_WRITE_MODE(engine, _MASKED_BIT_ENABLE(STOP_RING));
    		if (intel_wait_for_register(dev_priv,
    					    RING_MI_MODE(engine->mmio_base),
    					    MODE_IDLE,
    					    MODE_IDLE,
    					    1000)) {
    			DRM_ERROR("%s : timed out trying to stop ring\n",
    				  engine->name);
    			/* Sometimes we observe that the idle flag is not
    			 * set even though the ring is empty. So double
    			 * check before giving up.
    			 */
    			if (I915_READ_HEAD(engine) != I915_READ_TAIL(engine))
    				return false;
    		}
    	}
    
    	I915_WRITE_HEAD(engine, I915_READ_TAIL(engine));
    
    	I915_WRITE_HEAD(engine, 0);
    	I915_WRITE_TAIL(engine, 0);
    
    	/* The ring must be empty before it is disabled */
    	I915_WRITE_CTL(engine, 0);
    
    	return (I915_READ_HEAD(engine) & HEAD_ADDR) == 0;
    }
    
    static int init_ring_common(struct intel_engine_cs *engine)
    {
    	struct drm_i915_private *dev_priv = engine->i915;
    	struct intel_ring *ring = engine->buffer;
    	int ret = 0;
    
    	intel_uncore_forcewake_get(dev_priv, FORCEWAKE_ALL);
    
    	if (!stop_ring(engine)) {
    		/* G45 ring initialization often fails to reset head to zero */
    		DRM_DEBUG_DRIVER("%s head not reset to zero "
    				"ctl %08x head %08x tail %08x start %08x\n",
    				engine->name,
    				I915_READ_CTL(engine),
    				I915_READ_HEAD(engine),
    				I915_READ_TAIL(engine),
    				I915_READ_START(engine));
    
    		if (!stop_ring(engine)) {
    			DRM_ERROR("failed to set %s head to zero "
    				  "ctl %08x head %08x tail %08x start %08x\n",
    				  engine->name,
    				  I915_READ_CTL(engine),
    				  I915_READ_HEAD(engine),
    				  I915_READ_TAIL(engine),
    				  I915_READ_START(engine));
    			ret = -EIO;
    			goto out;
    		}
    	}
    
    	if (HWS_NEEDS_PHYSICAL(dev_priv))
    		ring_setup_phys_status_page(engine);
    	else
    		ring_setup_status_page(engine);
    
    	intel_engine_reset_breadcrumbs(engine);
    
    	/* Enforce ordering by reading HEAD register back */
    	I915_READ_HEAD(engine);
    
    	/* 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(engine, i915_ggtt_offset(ring->vma));
    
    	/* WaClearRingBufHeadRegAtInit:ctg,elk */
    	if (I915_READ_HEAD(engine))
    		DRM_DEBUG_DRIVER("%s initialization failed [head=%08x], fudging\n",
    				 engine->name, I915_READ_HEAD(engine));
    
    	/* Check that the ring offsets point within the ring! */
    	GEM_BUG_ON(!intel_ring_offset_valid(ring, ring->head));
    	GEM_BUG_ON(!intel_ring_offset_valid(ring, ring->tail));
    	intel_ring_update_space(ring);
    
    	/* First wake the ring up to an empty/idle ring */
    	I915_WRITE_HEAD(engine, ring->head);
    	I915_WRITE_TAIL(engine, ring->head);
    	(void)I915_READ_TAIL(engine);
    
    	I915_WRITE_CTL(engine, RING_CTL_SIZE(ring->size) | RING_VALID);
    
    	/* If the head is still not zero, the ring is dead */
    	if (intel_wait_for_register(dev_priv, RING_CTL(engine->mmio_base),
    				    RING_VALID, RING_VALID,
    				    50)) {
    		DRM_ERROR("%s initialization failed "
    			  "ctl %08x (valid? %d) head %08x [%08x] tail %08x [%08x] start %08x [expected %08x]\n",
    			  engine->name,
    			  I915_READ_CTL(engine),
    			  I915_READ_CTL(engine) & RING_VALID,
    			  I915_READ_HEAD(engine), ring->head,
    			  I915_READ_TAIL(engine), ring->tail,
    			  I915_READ_START(engine),
    			  i915_ggtt_offset(ring->vma));
    		ret = -EIO;
    		goto out;
    	}
    
    	if (INTEL_GEN(dev_priv) > 2)
    		I915_WRITE_MODE(engine, _MASKED_BIT_DISABLE(STOP_RING));
    
    	/* Now awake, let it get started */
    	if (ring->tail != ring->head) {
    		I915_WRITE_TAIL(engine, ring->tail);
    		(void)I915_READ_TAIL(engine);
    	}
    
    	/* Papering over lost _interrupts_ immediately following the restart */
    	intel_engine_queue_breadcrumbs(engine);
    out:
    	intel_uncore_forcewake_put(dev_priv, FORCEWAKE_ALL);
    
    	return ret;
    }
    
    static void reset_prepare(struct intel_engine_cs *engine)
    {
    	intel_engine_stop_cs(engine);
    }
    
    static void reset_ring(struct intel_engine_cs *engine, bool stalled)
    {
    	struct i915_timeline *tl = &engine->timeline;
    	struct i915_request *pos, *rq;
    	unsigned long flags;
    	u32 head;
    
    	rq = NULL;
    	spin_lock_irqsave(&tl->lock, flags);
    	list_for_each_entry(pos, &tl->requests, link) {
    		if (!i915_request_completed(pos)) {
    			rq = pos;
    			break;
    		}
    	}
    
    	GEM_TRACE("%s stalled? %s\n", engine->name, yesno(stalled));
    
    	/*
    	 * The guilty request will get skipped on a hung engine.
    	 *
    	 * Users of client default contexts do not rely on logical
    	 * state preserved between batches so it is safe to execute
    	 * queued requests following the hang. Non default contexts
    	 * rely on preserved state, so skipping a batch loses the
    	 * evolution of the state and it needs to be considered corrupted.
    	 * Executing more queued batches on top of corrupted state is
    	 * risky. But we take the risk by trying to advance through
    	 * the queued requests in order to make the client behaviour
    	 * more predictable around resets, by not throwing away random
    	 * amount of batches it has prepared for execution. Sophisticated
    	 * clients can use gem_reset_stats_ioctl and dma fence status
    	 * (exported via sync_file info ioctl on explicit fences) to observe
    	 * when it loses the context state and should rebuild accordingly.
    	 *
    	 * The context ban, and ultimately the client ban, mechanism are safety
    	 * valves if client submission ends up resulting in nothing more than
    	 * subsequent hangs.
    	 */
    
    	if (rq) {
    		/*
    		 * Try to restore the logical GPU state to match the
    		 * continuation of the request queue. If we skip the
    		 * context/PD restore, then the next request may try to execute
    		 * assuming that its context is valid and loaded on the GPU and
    		 * so may try to access invalid memory, prompting repeated GPU
    		 * hangs.
    		 *
    		 * If the request was guilty, we still restore the logical
    		 * state in case the next request requires it (e.g. the
    		 * aliasing ppgtt), but skip over the hung batch.
    		 *
    		 * If the request was innocent, we try to replay the request
    		 * with the restored context.
    		 */
    		i915_reset_request(rq, stalled);
    
    		GEM_BUG_ON(rq->ring != engine->buffer);
    		head = rq->head;
    	} else {
    		head = engine->buffer->tail;
    	}
    	engine->buffer->head = intel_ring_wrap(engine->buffer, head);
    
    	spin_unlock_irqrestore(&tl->lock, flags);
    }
    
    static void reset_finish(struct intel_engine_cs *engine)
    {
    }
    
    static int intel_rcs_ctx_init(struct i915_request *rq)
    {
    	int ret;
    
    	ret = intel_engine_emit_ctx_wa(rq);
    	if (ret != 0)
    		return ret;
    
    	ret = i915_gem_render_state_emit(rq);
    	if (ret)
    		return ret;
    
    	return 0;
    }
    
    static int init_render_ring(struct intel_engine_cs *engine)
    {
    	struct drm_i915_private *dev_priv = engine->i915;
    	int ret = init_ring_common(engine);
    	if (ret)
    		return ret;
    
    	/* WaTimedSingleVertexDispatch:cl,bw,ctg,elk,ilk,snb */
    	if (IS_GEN_RANGE(dev_priv, 4, 6))
    		I915_WRITE(MI_MODE, _MASKED_BIT_ENABLE(VS_TIMER_DISPATCH));
    
    	/* We need to disable the AsyncFlip performance optimisations in order
    	 * to use MI_WAIT_FOR_EVENT within the CS. It should already be
    	 * programmed to '1' on all products.
    	 *
    	 * WaDisableAsyncFlipPerfMode:snb,ivb,hsw,vlv
    	 */
    	if (IS_GEN_RANGE(dev_priv, 6, 7))
    		I915_WRITE(MI_MODE, _MASKED_BIT_ENABLE(ASYNC_FLIP_PERF_DISABLE));
    
    	/* Required for the hardware to program scanline values for waiting */
    	/* WaEnableFlushTlbInvalidationMode:snb */
    	if (IS_GEN(dev_priv, 6))
    		I915_WRITE(GFX_MODE,
    			   _MASKED_BIT_ENABLE(GFX_TLB_INVALIDATE_EXPLICIT));
    
    	/* WaBCSVCSTlbInvalidationMode:ivb,vlv,hsw */
    	if (IS_GEN(dev_priv, 7))
    		I915_WRITE(GFX_MODE_GEN7,
    			   _MASKED_BIT_ENABLE(GFX_TLB_INVALIDATE_EXPLICIT) |
    			   _MASKED_BIT_ENABLE(GFX_REPLAY_MODE));
    
    	if (IS_GEN(dev_priv, 6)) {
    		/* 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));
    	}
    
    	if (IS_GEN_RANGE(dev_priv, 6, 7))
    		I915_WRITE(INSTPM, _MASKED_BIT_ENABLE(INSTPM_FORCE_ORDERING));
    
    	if (INTEL_GEN(dev_priv) >= 6)
    		I915_WRITE_IMR(engine, ~engine->irq_keep_mask);
    
    	return 0;
    }
    
    static void cancel_requests(struct intel_engine_cs *engine)
    {
    	struct i915_request *request;
    	unsigned long flags;
    
    	spin_lock_irqsave(&engine->timeline.lock, flags);
    
    	/* Mark all submitted requests as skipped. */
    	list_for_each_entry(request, &engine->timeline.requests, link) {
    		if (!i915_request_signaled(request))
    			dma_fence_set_error(&request->fence, -EIO);
    
    		i915_request_mark_complete(request);
    	}
    
    	/* Remaining _unready_ requests will be nop'ed when submitted */
    
    	spin_unlock_irqrestore(&engine->timeline.lock, flags);
    }
    
    static void i9xx_submit_request(struct i915_request *request)
    {
    	struct drm_i915_private *dev_priv = request->i915;
    
    	i915_request_submit(request);
    
    	I915_WRITE_TAIL(request->engine,
    			intel_ring_set_tail(request->ring, request->tail));
    }
    
    static u32 *i9xx_emit_breadcrumb(struct i915_request *rq, u32 *cs)
    {
    	GEM_BUG_ON(rq->timeline->hwsp_ggtt != rq->engine->status_page.vma);
    	GEM_BUG_ON(offset_in_page(rq->timeline->hwsp_offset) != I915_GEM_HWS_SEQNO_ADDR);
    
    	*cs++ = MI_FLUSH;
    
    	*cs++ = MI_STORE_DWORD_INDEX;
    	*cs++ = I915_GEM_HWS_SEQNO_ADDR;
    	*cs++ = rq->fence.seqno;
    
    	*cs++ = MI_STORE_DWORD_INDEX;
    	*cs++ = I915_GEM_HWS_HANGCHECK_ADDR;
    	*cs++ = intel_engine_next_hangcheck_seqno(rq->engine);
    
    	*cs++ = MI_USER_INTERRUPT;
    
    	rq->tail = intel_ring_offset(rq, cs);
    	assert_ring_tail_valid(rq->ring, rq->tail);
    
    	return cs;
    }
    
    #define GEN5_WA_STORES 8 /* must be at least 1! */
    static u32 *gen5_emit_breadcrumb(struct i915_request *rq, u32 *cs)
    {
    	int i;
    
    	GEM_BUG_ON(rq->timeline->hwsp_ggtt != rq->engine->status_page.vma);
    	GEM_BUG_ON(offset_in_page(rq->timeline->hwsp_offset) != I915_GEM_HWS_SEQNO_ADDR);
    
    	*cs++ = MI_FLUSH;
    
    	*cs++ = MI_STORE_DWORD_INDEX;
    	*cs++ = I915_GEM_HWS_HANGCHECK_ADDR;
    	*cs++ = intel_engine_next_hangcheck_seqno(rq->engine);
    
    	BUILD_BUG_ON(GEN5_WA_STORES < 1);
    	for (i = 0; i < GEN5_WA_STORES; i++) {
    		*cs++ = MI_STORE_DWORD_INDEX;
    		*cs++ = I915_GEM_HWS_SEQNO_ADDR;
    		*cs++ = rq->fence.seqno;
    	}
    
    	*cs++ = MI_USER_INTERRUPT;
    	*cs++ = MI_NOOP;
    
    	rq->tail = intel_ring_offset(rq, cs);
    	assert_ring_tail_valid(rq->ring, rq->tail);
    
    	return cs;
    }
    #undef GEN5_WA_STORES
    
    static void
    gen5_irq_enable(struct intel_engine_cs *engine)
    {
    	gen5_enable_gt_irq(engine->i915, engine->irq_enable_mask);
    }
    
    static void
    gen5_irq_disable(struct intel_engine_cs *engine)
    {
    	gen5_disable_gt_irq(engine->i915, engine->irq_enable_mask);
    }
    
    static void
    i9xx_irq_enable(struct intel_engine_cs *engine)
    {
    	struct drm_i915_private *dev_priv = engine->i915;
    
    	dev_priv->irq_mask &= ~engine->irq_enable_mask;
    	I915_WRITE(IMR, dev_priv->irq_mask);
    	POSTING_READ_FW(RING_IMR(engine->mmio_base));
    }
    
    static void
    i9xx_irq_disable(struct intel_engine_cs *engine)
    {
    	struct drm_i915_private *dev_priv = engine->i915;
    
    	dev_priv->irq_mask |= engine->irq_enable_mask;
    	I915_WRITE(IMR, dev_priv->irq_mask);
    }
    
    static void
    i8xx_irq_enable(struct intel_engine_cs *engine)
    {
    	struct drm_i915_private *dev_priv = engine->i915;
    
    	dev_priv->irq_mask &= ~engine->irq_enable_mask;
    	I915_WRITE16(IMR, dev_priv->irq_mask);
    	POSTING_READ16(RING_IMR(engine->mmio_base));
    }
    
    static void
    i8xx_irq_disable(struct intel_engine_cs *engine)
    {
    	struct drm_i915_private *dev_priv = engine->i915;
    
    	dev_priv->irq_mask |= engine->irq_enable_mask;
    	I915_WRITE16(IMR, dev_priv->irq_mask);
    }
    
    static int
    bsd_ring_flush(struct i915_request *rq, u32 mode)
    {
    	u32 *cs;
    
    	cs = intel_ring_begin(rq, 2);
    	if (IS_ERR(cs))
    		return PTR_ERR(cs);
    
    	*cs++ = MI_FLUSH;
    	*cs++ = MI_NOOP;
    	intel_ring_advance(rq, cs);
    	return 0;
    }
    
    static void
    gen6_irq_enable(struct intel_engine_cs *engine)
    {
    	struct drm_i915_private *dev_priv = engine->i915;
    
    	I915_WRITE_IMR(engine,
    		       ~(engine->irq_enable_mask |
    			 engine->irq_keep_mask));
    
    	/* Flush/delay to ensure the RING_IMR is active before the GT IMR */
    	POSTING_READ_FW(RING_IMR(engine->mmio_base));
    
    	gen5_enable_gt_irq(dev_priv, engine->irq_enable_mask);
    }
    
    static void
    gen6_irq_disable(struct intel_engine_cs *engine)
    {
    	struct drm_i915_private *dev_priv = engine->i915;
    
    	I915_WRITE_IMR(engine, ~engine->irq_keep_mask);
    	gen5_disable_gt_irq(dev_priv, engine->irq_enable_mask);
    }
    
    static void
    hsw_vebox_irq_enable(struct intel_engine_cs *engine)
    {
    	struct drm_i915_private *dev_priv = engine->i915;
    
    	I915_WRITE_IMR(engine, ~engine->irq_enable_mask);
    
    	/* Flush/delay to ensure the RING_IMR is active before the GT IMR */
    	POSTING_READ_FW(RING_IMR(engine->mmio_base));
    
    	gen6_unmask_pm_irq(dev_priv, engine->irq_enable_mask);
    }
    
    static void
    hsw_vebox_irq_disable(struct intel_engine_cs *engine)
    {
    	struct drm_i915_private *dev_priv = engine->i915;
    
    	I915_WRITE_IMR(engine, ~0);
    	gen6_mask_pm_irq(dev_priv, engine->irq_enable_mask);
    }
    
    static int
    i965_emit_bb_start(struct i915_request *rq,
    		   u64 offset, u32 length,
    		   unsigned int dispatch_flags)
    {
    	u32 *cs;
    
    	cs = intel_ring_begin(rq, 2);
    	if (IS_ERR(cs))
    		return PTR_ERR(cs);
    
    	*cs++ = MI_BATCH_BUFFER_START | MI_BATCH_GTT | (dispatch_flags &
    		I915_DISPATCH_SECURE ? 0 : MI_BATCH_NON_SECURE_I965);
    	*cs++ = offset;
    	intel_ring_advance(rq, cs);
    
    	return 0;
    }
    
    /* Just userspace ABI convention to limit the wa batch bo to a resonable size */
    #define I830_BATCH_LIMIT SZ_256K
    #define I830_TLB_ENTRIES (2)
    #define I830_WA_SIZE max(I830_TLB_ENTRIES*4096, I830_BATCH_LIMIT)
    static int
    i830_emit_bb_start(struct i915_request *rq,
    		   u64 offset, u32 len,
    		   unsigned int dispatch_flags)
    {
    	u32 *cs, cs_offset = i915_scratch_offset(rq->i915);
    
    	GEM_BUG_ON(rq->i915->gt.scratch->size < I830_WA_SIZE);
    
    	cs = intel_ring_begin(rq, 6);
    	if (IS_ERR(cs))
    		return PTR_ERR(cs);
    
    	/* Evict the invalid PTE TLBs */
    	*cs++ = COLOR_BLT_CMD | BLT_WRITE_RGBA;
    	*cs++ = BLT_DEPTH_32 | BLT_ROP_COLOR_COPY | 4096;
    	*cs++ = I830_TLB_ENTRIES << 16 | 4; /* load each page */
    	*cs++ = cs_offset;
    	*cs++ = 0xdeadbeef;
    	*cs++ = MI_NOOP;
    	intel_ring_advance(rq, cs);
    
    	if ((dispatch_flags & I915_DISPATCH_PINNED) == 0) {
    		if (len > I830_BATCH_LIMIT)
    			return -ENOSPC;
    
    		cs = intel_ring_begin(rq, 6 + 2);
    		if (IS_ERR(cs))
    			return PTR_ERR(cs);
    
    		/* Blit the batch (which has now all relocs applied) to the
    		 * stable batch scratch bo area (so that the CS never
    		 * stumbles over its tlb invalidation bug) ...
    		 */
    		*cs++ = SRC_COPY_BLT_CMD | BLT_WRITE_RGBA;
    		*cs++ = BLT_DEPTH_32 | BLT_ROP_SRC_COPY | 4096;
    		*cs++ = DIV_ROUND_UP(len, 4096) << 16 | 4096;
    		*cs++ = cs_offset;
    		*cs++ = 4096;
    		*cs++ = offset;
    
    		*cs++ = MI_FLUSH;
    		*cs++ = MI_NOOP;
    		intel_ring_advance(rq, cs);
    
    		/* ... and execute it. */
    		offset = cs_offset;
    	}
    
    	cs = intel_ring_begin(rq, 2);
    	if (IS_ERR(cs))
    		return PTR_ERR(cs);
    
    	*cs++ = MI_BATCH_BUFFER_START | MI_BATCH_GTT;
    	*cs++ = offset | (dispatch_flags & I915_DISPATCH_SECURE ? 0 :
    		MI_BATCH_NON_SECURE);
    	intel_ring_advance(rq, cs);
    
    	return 0;
    }
    
    static int
    i915_emit_bb_start(struct i915_request *rq,
    		   u64 offset, u32 len,
    		   unsigned int dispatch_flags)
    {
    	u32 *cs;
    
    	cs = intel_ring_begin(rq, 2);
    	if (IS_ERR(cs))
    		return PTR_ERR(cs);
    
    	*cs++ = MI_BATCH_BUFFER_START | MI_BATCH_GTT;
    	*cs++ = offset | (dispatch_flags & I915_DISPATCH_SECURE ? 0 :
    		MI_BATCH_NON_SECURE);
    	intel_ring_advance(rq, cs);
    
    	return 0;
    }
    
    int intel_ring_pin(struct intel_ring *ring)
    {
    	struct i915_vma *vma = ring->vma;
    	enum i915_map_type map = i915_coherent_map_type(vma->vm->i915);
    	unsigned int flags;
    	void *addr;
    	int ret;
    
    	GEM_BUG_ON(ring->vaddr);
    
    	ret = i915_timeline_pin(ring->timeline);
    	if (ret)
    		return ret;
    
    	flags = PIN_GLOBAL;
    
    	/* Ring wraparound at offset 0 sometimes hangs. No idea why. */
    	flags |= PIN_OFFSET_BIAS | i915_ggtt_pin_bias(vma);
    
    	if (vma->obj->stolen)
    		flags |= PIN_MAPPABLE;
    	else
    		flags |= PIN_HIGH;
    
    	if (!(vma->flags & I915_VMA_GLOBAL_BIND)) {
    		if (flags & PIN_MAPPABLE || map == I915_MAP_WC)
    			ret = i915_gem_object_set_to_gtt_domain(vma->obj, true);
    		else
    			ret = i915_gem_object_set_to_cpu_domain(vma->obj, true);
    		if (unlikely(ret))
    			goto unpin_timeline;
    	}
    
    	ret = i915_vma_pin(vma, 0, 0, flags);
    	if (unlikely(ret))
    		goto unpin_timeline;
    
    	if (i915_vma_is_map_and_fenceable(vma))
    		addr = (void __force *)i915_vma_pin_iomap(vma);
    	else
    		addr = i915_gem_object_pin_map(vma->obj, map);
    	if (IS_ERR(addr)) {
    		ret = PTR_ERR(addr);
    		goto unpin_ring;
    	}
    
    	vma->obj->pin_global++;
    
    	ring->vaddr = addr;
    	return 0;
    
    unpin_ring:
    	i915_vma_unpin(vma);
    unpin_timeline:
    	i915_timeline_unpin(ring->timeline);
    	return ret;
    }
    
    void intel_ring_reset(struct intel_ring *ring, u32 tail)
    {
    	GEM_BUG_ON(!intel_ring_offset_valid(ring, tail));
    
    	ring->tail = tail;
    	ring->head = tail;
    	ring->emit = tail;
    	intel_ring_update_space(ring);
    }
    
    void intel_ring_unpin(struct intel_ring *ring)
    {
    	GEM_BUG_ON(!ring->vma);
    	GEM_BUG_ON(!ring->vaddr);
    
    	/* Discard any unused bytes beyond that submitted to hw. */
    	intel_ring_reset(ring, ring->tail);
    
    	if (i915_vma_is_map_and_fenceable(ring->vma))
    		i915_vma_unpin_iomap(ring->vma);
    	else
    		i915_gem_object_unpin_map(ring->vma->obj);
    	ring->vaddr = NULL;
    
    	ring->vma->obj->pin_global--;
    	i915_vma_unpin(ring->vma);
    
    	i915_timeline_unpin(ring->timeline);
    }
    
    static struct i915_vma *
    intel_ring_create_vma(struct drm_i915_private *dev_priv, int size)
    {
    	struct i915_address_space *vm = &dev_priv->ggtt.vm;
    	struct drm_i915_gem_object *obj;
    	struct i915_vma *vma;
    
    	obj = i915_gem_object_create_stolen(dev_priv, size);
    	if (!obj)
    		obj = i915_gem_object_create_internal(dev_priv, size);
    	if (IS_ERR(obj))
    		return ERR_CAST(obj);
    
    	/*
    	 * Mark ring buffers as read-only from GPU side (so no stray overwrites)
    	 * if supported by the platform's GGTT.
    	 */
    	if (vm->has_read_only)
    		i915_gem_object_set_readonly(obj);
    
    	vma = i915_vma_instance(obj, vm, NULL);
    	if (IS_ERR(vma))
    		goto err;
    
    	return vma;
    
    err:
    	i915_gem_object_put(obj);
    	return vma;
    }
    
    struct intel_ring *
    intel_engine_create_ring(struct intel_engine_cs *engine,
    			 struct i915_timeline *timeline,
    			 int size)
    {
    	struct intel_ring *ring;
    	struct i915_vma *vma;
    
    	GEM_BUG_ON(!is_power_of_2(size));
    	GEM_BUG_ON(RING_CTL_SIZE(size) & ~RING_NR_PAGES);
    	GEM_BUG_ON(timeline == &engine->timeline);
    	lockdep_assert_held(&engine->i915->drm.struct_mutex);
    
    	ring = kzalloc(sizeof(*ring), GFP_KERNEL);
    	if (!ring)
    		return ERR_PTR(-ENOMEM);
    
    	INIT_LIST_HEAD(&ring->request_list);
    	ring->timeline = i915_timeline_get(timeline);
    
    	ring->size = size;
    	/* 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 = size;
    	if (IS_I830(engine->i915) || IS_I845G(engine->i915))
    		ring->effective_size -= 2 * CACHELINE_BYTES;
    
    	intel_ring_update_space(ring);
    
    	vma = intel_ring_create_vma(engine->i915, size);
    	if (IS_ERR(vma)) {
    		kfree(ring);
    		return ERR_CAST(vma);
    	}
    	ring->vma = vma;
    
    	return ring;
    }
    
    void
    intel_ring_free(struct intel_ring *ring)
    {
    	struct drm_i915_gem_object *obj = ring->vma->obj;
    
    	i915_vma_close(ring->vma);
    	__i915_gem_object_release_unless_active(obj);
    
    	i915_timeline_put(ring->timeline);
    	kfree(ring);
    }
    
    static void __ring_context_fini(struct intel_context *ce)
    {
    	GEM_BUG_ON(i915_gem_object_is_active(ce->state->obj));
    	i915_gem_object_put(ce->state->obj);
    }
    
    static void ring_context_destroy(struct intel_context *ce)
    {
    	GEM_BUG_ON(ce->pin_count);
    
    	if (ce->state)
    		__ring_context_fini(ce);
    
    	intel_context_free(ce);
    }
    
    static int __context_pin_ppgtt(struct i915_gem_context *ctx)
    {
    	struct i915_hw_ppgtt *ppgtt;
    	int err = 0;
    
    	ppgtt = ctx->ppgtt ?: ctx->i915->mm.aliasing_ppgtt;
    	if (ppgtt)
    		err = gen6_ppgtt_pin(ppgtt);
    
    	return err;
    }
    
    static void __context_unpin_ppgtt(struct i915_gem_context *ctx)
    {
    	struct i915_hw_ppgtt *ppgtt;
    
    	ppgtt = ctx->ppgtt ?: ctx->i915->mm.aliasing_ppgtt;
    	if (ppgtt)
    		gen6_ppgtt_unpin(ppgtt);
    }
    
    static int __context_pin(struct intel_context *ce)
    {
    	struct i915_vma *vma;
    	int err;
    
    	vma = ce->state;
    	if (!vma)
    		return 0;
    
    	/*
    	 * Clear this page out of any CPU caches for coherent swap-in/out.
    	 * We only want to do this on the first bind so that we do not stall
    	 * on an active context (which by nature is already on the GPU).
    	 */
    	if (!(vma->flags & I915_VMA_GLOBAL_BIND)) {
    		err = i915_gem_object_set_to_gtt_domain(vma->obj, true);
    		if (err)
    			return err;
    	}
    
    	err = i915_vma_pin(vma, 0, 0, PIN_GLOBAL | PIN_HIGH);
    	if (err)
    		return err;
    
    	/*
    	 * And mark is as a globally pinned object to let the shrinker know
    	 * it cannot reclaim the object until we release it.
    	 */
    	vma->obj->pin_global++;
    
    	return 0;
    }
    
    static void __context_unpin(struct intel_context *ce)
    {
    	struct i915_vma *vma;
    
    	vma = ce->state;
    	if (!vma)
    		return;
    
    	vma->obj->pin_global--;
    	i915_vma_unpin(vma);
    }
    
    static void ring_context_unpin(struct intel_context *ce)
    {
    	__context_unpin_ppgtt(ce->gem_context);
    	__context_unpin(ce);
    
    	list_del(&ce->active_link);
    	i915_gem_context_put(ce->gem_context);
    }
    
    static struct i915_vma *
    alloc_context_vma(struct intel_engine_cs *engine)
    {
    	struct drm_i915_private *i915 = engine->i915;
    	struct drm_i915_gem_object *obj;
    	struct i915_vma *vma;
    	int err;
    
    	obj = i915_gem_object_create(i915, engine->context_size);
    	if (IS_ERR(obj))
    		return ERR_CAST(obj);
    
    	if (engine->default_state) {
    		void *defaults, *vaddr;
    
    		vaddr = i915_gem_object_pin_map(obj, I915_MAP_WB);
    		if (IS_ERR(vaddr)) {
    			err = PTR_ERR(vaddr);
    			goto err_obj;
    		}
    
    		defaults = i915_gem_object_pin_map(engine->default_state,
    						   I915_MAP_WB);
    		if (IS_ERR(defaults)) {
    			err = PTR_ERR(defaults);
    			goto err_map;
    		}
    
    		memcpy(vaddr, defaults, engine->context_size);
    
    		i915_gem_object_unpin_map(engine->default_state);
    		i915_gem_object_unpin_map(obj);
    	}
    
    	/*
    	 * Try to make the context utilize L3 as well as LLC.
    	 *
    	 * On VLV we don't have L3 controls in the PTEs so we
    	 * shouldn't touch the cache level, especially as that
    	 * would make the object snooped which might have a
    	 * negative performance impact.
    	 *
    	 * Snooping is required on non-llc platforms in execlist
    	 * mode, but since all GGTT accesses use PAT entry 0 we
    	 * get snooping anyway regardless of cache_level.
    	 *
    	 * This is only applicable for Ivy Bridge devices since
    	 * later platforms don't have L3 control bits in the PTE.
    	 */
    	if (IS_IVYBRIDGE(i915)) {
    		/* Ignore any error, regard it as a simple optimisation */
    		i915_gem_object_set_cache_level(obj, I915_CACHE_L3_LLC);
    	}
    
    	vma = i915_vma_instance(obj, &i915->ggtt.vm, NULL);
    	if (IS_ERR(vma)) {
    		err = PTR_ERR(vma);
    		goto err_obj;
    	}
    
    	return vma;
    
    err_map:
    	i915_gem_object_unpin_map(obj);
    err_obj:
    	i915_gem_object_put(obj);
    	return ERR_PTR(err);
    }
    
    static int ring_context_pin(struct intel_context *ce)
    {
    	struct intel_engine_cs *engine = ce->engine;
    	int err;
    
    	/* One ringbuffer to rule them all */
    	GEM_BUG_ON(!engine->buffer);
    	ce->ring = engine->buffer;
    
    	if (!ce->state && engine->context_size) {
    		struct i915_vma *vma;
    
    		vma = alloc_context_vma(engine);
    		if (IS_ERR(vma))
    			return PTR_ERR(vma);
    
    		ce->state = vma;
    	}
    
    	err = __context_pin(ce);
    	if (err)
    		return err;
    
    	err = __context_pin_ppgtt(ce->gem_context);
    	if (err)
    		goto err_unpin;
    
    	return 0;
    
    err_unpin:
    	__context_unpin(ce);
    	return err;
    }
    
    static const struct intel_context_ops ring_context_ops = {
    	.pin = ring_context_pin,
    	.unpin = ring_context_unpin,
    	.destroy = ring_context_destroy,
    };
    
    static int intel_init_ring_buffer(struct intel_engine_cs *engine)
    {
    	struct i915_timeline *timeline;
    	struct intel_ring *ring;
    	int err;
    
    	err = intel_engine_setup_common(engine);
    	if (err)
    		return err;
    
    	timeline = i915_timeline_create(engine->i915,
    					engine->name,
    					engine->status_page.vma);
    	if (IS_ERR(timeline)) {
    		err = PTR_ERR(timeline);
    		goto err;
    	}
    	GEM_BUG_ON(timeline->has_initial_breadcrumb);
    
    	ring = intel_engine_create_ring(engine, timeline, 32 * PAGE_SIZE);
    	i915_timeline_put(timeline);
    	if (IS_ERR(ring)) {
    		err = PTR_ERR(ring);
    		goto err;
    	}
    
    	err = intel_ring_pin(ring);
    	if (err)
    		goto err_ring;
    
    	GEM_BUG_ON(engine->buffer);
    	engine->buffer = ring;
    
    	err = intel_engine_init_common(engine);
    	if (err)
    		goto err_unpin;
    
    	GEM_BUG_ON(ring->timeline->hwsp_ggtt != engine->status_page.vma);
    
    	return 0;
    
    err_unpin:
    	intel_ring_unpin(ring);
    err_ring:
    	intel_ring_free(ring);
    err:
    	intel_engine_cleanup_common(engine);
    	return err;
    }
    
    void intel_engine_cleanup(struct intel_engine_cs *engine)
    {
    	struct drm_i915_private *dev_priv = engine->i915;
    
    	WARN_ON(INTEL_GEN(dev_priv) > 2 &&
    		(I915_READ_MODE(engine) & MODE_IDLE) == 0);
    
    	intel_ring_unpin(engine->buffer);
    	intel_ring_free(engine->buffer);
    
    	if (engine->cleanup)
    		engine->cleanup(engine);
    
    	intel_engine_cleanup_common(engine);
    
    	dev_priv->engine[engine->id] = NULL;
    	kfree(engine);
    }
    
    void intel_legacy_submission_resume(struct drm_i915_private *dev_priv)
    {
    	struct intel_engine_cs *engine;
    	enum intel_engine_id id;
    
    	/* Restart from the beginning of the rings for convenience */
    	for_each_engine(engine, dev_priv, id)
    		intel_ring_reset(engine->buffer, 0);
    }
    
    static int load_pd_dir(struct i915_request *rq,
    		       const struct i915_hw_ppgtt *ppgtt)
    {
    	const struct intel_engine_cs * const engine = rq->engine;
    	u32 *cs;
    
    	cs = intel_ring_begin(rq, 6);
    	if (IS_ERR(cs))
    		return PTR_ERR(cs);
    
    	*cs++ = MI_LOAD_REGISTER_IMM(1);
    	*cs++ = i915_mmio_reg_offset(RING_PP_DIR_DCLV(engine));
    	*cs++ = PP_DIR_DCLV_2G;
    
    	*cs++ = MI_LOAD_REGISTER_IMM(1);
    	*cs++ = i915_mmio_reg_offset(RING_PP_DIR_BASE(engine));
    	*cs++ = ppgtt->pd.base.ggtt_offset << 10;
    
    	intel_ring_advance(rq, cs);
    
    	return 0;
    }
    
    static int flush_pd_dir(struct i915_request *rq)
    {
    	const struct intel_engine_cs * const engine = rq->engine;
    	u32 *cs;
    
    	cs = intel_ring_begin(rq, 4);
    	if (IS_ERR(cs))
    		return PTR_ERR(cs);
    
    	/* Stall until the page table load is complete */
    	*cs++ = MI_STORE_REGISTER_MEM | MI_SRM_LRM_GLOBAL_GTT;
    	*cs++ = i915_mmio_reg_offset(RING_PP_DIR_BASE(engine));
    	*cs++ = i915_scratch_offset(rq->i915);
    	*cs++ = MI_NOOP;
    
    	intel_ring_advance(rq, cs);
    	return 0;
    }
    
    static inline int mi_set_context(struct i915_request *rq, u32 flags)
    {
    	struct drm_i915_private *i915 = rq->i915;
    	struct intel_engine_cs *engine = rq->engine;
    	enum intel_engine_id id;
    	const int num_engines =
    		IS_HSW_GT1(i915) ? RUNTIME_INFO(i915)->num_engines - 1 : 0;
    	bool force_restore = false;
    	int len;
    	u32 *cs;
    
    	flags |= MI_MM_SPACE_GTT;
    	if (IS_HASWELL(i915))
    		/* These flags are for resource streamer on HSW+ */
    		flags |= HSW_MI_RS_SAVE_STATE_EN | HSW_MI_RS_RESTORE_STATE_EN;
    	else
    		flags |= MI_SAVE_EXT_STATE_EN | MI_RESTORE_EXT_STATE_EN;
    
    	len = 4;
    	if (IS_GEN(i915, 7))
    		len += 2 + (num_engines ? 4 * num_engines + 6 : 0);
    	if (flags & MI_FORCE_RESTORE) {
    		GEM_BUG_ON(flags & MI_RESTORE_INHIBIT);
    		flags &= ~MI_FORCE_RESTORE;
    		force_restore = true;
    		len += 2;
    	}
    
    	cs = intel_ring_begin(rq, len);
    	if (IS_ERR(cs))
    		return PTR_ERR(cs);
    
    	/* WaProgramMiArbOnOffAroundMiSetContext:ivb,vlv,hsw,bdw,chv */
    	if (IS_GEN(i915, 7)) {
    		*cs++ = MI_ARB_ON_OFF | MI_ARB_DISABLE;
    		if (num_engines) {
    			struct intel_engine_cs *signaller;
    
    			*cs++ = MI_LOAD_REGISTER_IMM(num_engines);
    			for_each_engine(signaller, i915, id) {
    				if (signaller == engine)
    					continue;
    
    				*cs++ = i915_mmio_reg_offset(
    					   RING_PSMI_CTL(signaller->mmio_base));
    				*cs++ = _MASKED_BIT_ENABLE(
    						GEN6_PSMI_SLEEP_MSG_DISABLE);
    			}
    		}
    	}
    
    	if (force_restore) {
    		/*
    		 * The HW doesn't handle being told to restore the current
    		 * context very well. Quite often it likes goes to go off and
    		 * sulk, especially when it is meant to be reloading PP_DIR.
    		 * A very simple fix to force the reload is to simply switch
    		 * away from the current context and back again.
    		 *
    		 * Note that the kernel_context will contain random state
    		 * following the INHIBIT_RESTORE. We accept this since we
    		 * never use the kernel_context state; it is merely a
    		 * placeholder we use to flush other contexts.
    		 */
    		*cs++ = MI_SET_CONTEXT;
    		*cs++ = i915_ggtt_offset(intel_context_lookup(i915->kernel_context,
    							      engine)->state) |
    			MI_MM_SPACE_GTT |
    			MI_RESTORE_INHIBIT;
    	}
    
    	*cs++ = MI_NOOP;
    	*cs++ = MI_SET_CONTEXT;
    	*cs++ = i915_ggtt_offset(rq->hw_context->state) | flags;
    	/*
    	 * w/a: MI_SET_CONTEXT must always be followed by MI_NOOP
    	 * WaMiSetContext_Hang:snb,ivb,vlv
    	 */
    	*cs++ = MI_NOOP;
    
    	if (IS_GEN(i915, 7)) {
    		if (num_engines) {
    			struct intel_engine_cs *signaller;
    			i915_reg_t last_reg = {}; /* keep gcc quiet */
    
    			*cs++ = MI_LOAD_REGISTER_IMM(num_engines);
    			for_each_engine(signaller, i915, id) {
    				if (signaller == engine)
    					continue;
    
    				last_reg = RING_PSMI_CTL(signaller->mmio_base);
    				*cs++ = i915_mmio_reg_offset(last_reg);
    				*cs++ = _MASKED_BIT_DISABLE(
    						GEN6_PSMI_SLEEP_MSG_DISABLE);
    			}
    
    			/* Insert a delay before the next switch! */
    			*cs++ = MI_STORE_REGISTER_MEM | MI_SRM_LRM_GLOBAL_GTT;
    			*cs++ = i915_mmio_reg_offset(last_reg);
    			*cs++ = i915_scratch_offset(rq->i915);
    			*cs++ = MI_NOOP;
    		}
    		*cs++ = MI_ARB_ON_OFF | MI_ARB_ENABLE;
    	}
    
    	intel_ring_advance(rq, cs);
    
    	return 0;
    }
    
    static int remap_l3(struct i915_request *rq, int slice)
    {
    	u32 *cs, *remap_info = rq->i915->l3_parity.remap_info[slice];
    	int i;
    
    	if (!remap_info)
    		return 0;
    
    	cs = intel_ring_begin(rq, GEN7_L3LOG_SIZE/4 * 2 + 2);
    	if (IS_ERR(cs))
    		return PTR_ERR(cs);
    
    	/*
    	 * Note: We do not worry about the concurrent register cacheline hang
    	 * here because no other code should access these registers other than
    	 * at initialization time.
    	 */
    	*cs++ = MI_LOAD_REGISTER_IMM(GEN7_L3LOG_SIZE/4);
    	for (i = 0; i < GEN7_L3LOG_SIZE/4; i++) {
    		*cs++ = i915_mmio_reg_offset(GEN7_L3LOG(slice, i));
    		*cs++ = remap_info[i];
    	}
    	*cs++ = MI_NOOP;
    	intel_ring_advance(rq, cs);
    
    	return 0;
    }
    
    static int switch_context(struct i915_request *rq)
    {
    	struct intel_engine_cs *engine = rq->engine;
    	struct i915_gem_context *ctx = rq->gem_context;
    	struct i915_hw_ppgtt *ppgtt = ctx->ppgtt ?: rq->i915->mm.aliasing_ppgtt;
    	unsigned int unwind_mm = 0;
    	u32 hw_flags = 0;
    	int ret, i;
    
    	lockdep_assert_held(&rq->i915->drm.struct_mutex);
    	GEM_BUG_ON(HAS_EXECLISTS(rq->i915));
    
    	if (ppgtt) {
    		int loops;
    
    		/*
    		 * Baytail takes a little more convincing that it really needs
    		 * to reload the PD between contexts. It is not just a little
    		 * longer, as adding more stalls after the load_pd_dir (i.e.
    		 * adding a long loop around flush_pd_dir) is not as effective
    		 * as reloading the PD umpteen times. 32 is derived from
    		 * experimentation (gem_exec_parallel/fds) and has no good
    		 * explanation.
    		 */
    		loops = 1;
    		if (engine->id == BCS0 && IS_VALLEYVIEW(engine->i915))
    			loops = 32;
    
    		do {
    			ret = load_pd_dir(rq, ppgtt);
    			if (ret)
    				goto err;
    		} while (--loops);
    
    		if (ppgtt->pd_dirty_engines & engine->mask) {
    			unwind_mm = engine->mask;
    			ppgtt->pd_dirty_engines &= ~unwind_mm;
    			hw_flags = MI_FORCE_RESTORE;
    		}
    	}
    
    	if (rq->hw_context->state) {
    		GEM_BUG_ON(engine->id != RCS0);
    
    		/*
    		 * The kernel context(s) is treated as pure scratch and is not
    		 * expected to retain any state (as we sacrifice it during
    		 * suspend and on resume it may be corrupted). This is ok,
    		 * as nothing actually executes using the kernel context; it
    		 * is purely used for flushing user contexts.
    		 */
    		if (i915_gem_context_is_kernel(ctx))
    			hw_flags = MI_RESTORE_INHIBIT;
    
    		ret = mi_set_context(rq, hw_flags);
    		if (ret)
    			goto err_mm;
    	}
    
    	if (ppgtt) {
    		ret = engine->emit_flush(rq, EMIT_INVALIDATE);
    		if (ret)
    			goto err_mm;
    
    		ret = flush_pd_dir(rq);
    		if (ret)
    			goto err_mm;
    
    		/*
    		 * Not only do we need a full barrier (post-sync write) after
    		 * invalidating the TLBs, but we need to wait a little bit
    		 * longer. Whether this is merely delaying us, or the
    		 * subsequent flush is a key part of serialising with the
    		 * post-sync op, this extra pass appears vital before a
    		 * mm switch!
    		 */
    		ret = engine->emit_flush(rq, EMIT_INVALIDATE);
    		if (ret)
    			goto err_mm;
    
    		ret = engine->emit_flush(rq, EMIT_FLUSH);
    		if (ret)
    			goto err_mm;
    	}
    
    	if (ctx->remap_slice) {
    		for (i = 0; i < MAX_L3_SLICES; i++) {
    			if (!(ctx->remap_slice & BIT(i)))
    				continue;
    
    			ret = remap_l3(rq, i);
    			if (ret)
    				goto err_mm;
    		}
    
    		ctx->remap_slice = 0;
    	}
    
    	return 0;
    
    err_mm:
    	if (unwind_mm)
    		ppgtt->pd_dirty_engines |= unwind_mm;
    err:
    	return ret;
    }
    
    static int ring_request_alloc(struct i915_request *request)
    {
    	int ret;
    
    	GEM_BUG_ON(!request->hw_context->pin_count);
    	GEM_BUG_ON(request->timeline->has_initial_breadcrumb);
    
    	/*
    	 * Flush enough space to reduce the likelihood of waiting after
    	 * we start building the request - in which case we will just
    	 * have to repeat work.
    	 */
    	request->reserved_space += LEGACY_REQUEST_SIZE;
    
    	ret = switch_context(request);
    	if (ret)
    		return ret;
    
    	/* Unconditionally invalidate GPU caches and TLBs. */
    	ret = request->engine->emit_flush(request, EMIT_INVALIDATE);
    	if (ret)
    		return ret;
    
    	request->reserved_space -= LEGACY_REQUEST_SIZE;
    	return 0;
    }
    
    static noinline int wait_for_space(struct intel_ring *ring, unsigned int bytes)
    {
    	struct i915_request *target;
    	long timeout;
    
    	lockdep_assert_held(&ring->vma->vm->i915->drm.struct_mutex);
    
    	if (intel_ring_update_space(ring) >= bytes)
    		return 0;
    
    	GEM_BUG_ON(list_empty(&ring->request_list));
    	list_for_each_entry(target, &ring->request_list, ring_link) {
    		/* Would completion of this request free enough space? */
    		if (bytes <= __intel_ring_space(target->postfix,
    						ring->emit, ring->size))
    			break;
    	}
    
    	if (WARN_ON(&target->ring_link == &ring->request_list))
    		return -ENOSPC;
    
    	timeout = i915_request_wait(target,
    				    I915_WAIT_INTERRUPTIBLE | I915_WAIT_LOCKED,
    				    MAX_SCHEDULE_TIMEOUT);
    	if (timeout < 0)
    		return timeout;
    
    	i915_request_retire_upto(target);
    
    	intel_ring_update_space(ring);
    	GEM_BUG_ON(ring->space < bytes);
    	return 0;
    }
    
    u32 *intel_ring_begin(struct i915_request *rq, unsigned int num_dwords)
    {
    	struct intel_ring *ring = rq->ring;
    	const unsigned int remain_usable = ring->effective_size - ring->emit;
    	const unsigned int bytes = num_dwords * sizeof(u32);
    	unsigned int need_wrap = 0;
    	unsigned int total_bytes;
    	u32 *cs;
    
    	/* Packets must be qword aligned. */
    	GEM_BUG_ON(num_dwords & 1);
    
    	total_bytes = bytes + rq->reserved_space;
    	GEM_BUG_ON(total_bytes > ring->effective_size);
    
    	if (unlikely(total_bytes > remain_usable)) {
    		const int remain_actual = ring->size - ring->emit;
    
    		if (bytes > remain_usable) {
    			/*
    			 * Not enough space for the basic request. So need to
    			 * flush out the remainder and then wait for
    			 * base + reserved.
    			 */
    			total_bytes += remain_actual;
    			need_wrap = remain_actual | 1;
    		} else  {
    			/*
    			 * The base request will fit but the reserved space
    			 * falls off the end. So we don't need an immediate
    			 * wrap and only need to effectively wait for the
    			 * reserved size from the start of ringbuffer.
    			 */
    			total_bytes = rq->reserved_space + remain_actual;
    		}
    	}
    
    	if (unlikely(total_bytes > ring->space)) {
    		int ret;
    
    		/*
    		 * Space is reserved in the ringbuffer for finalising the
    		 * request, as that cannot be allowed to fail. During request
    		 * finalisation, reserved_space is set to 0 to stop the
    		 * overallocation and the assumption is that then we never need
    		 * to wait (which has the risk of failing with EINTR).
    		 *
    		 * See also i915_request_alloc() and i915_request_add().
    		 */
    		GEM_BUG_ON(!rq->reserved_space);
    
    		ret = wait_for_space(ring, total_bytes);
    		if (unlikely(ret))
    			return ERR_PTR(ret);
    	}
    
    	if (unlikely(need_wrap)) {
    		need_wrap &= ~1;
    		GEM_BUG_ON(need_wrap > ring->space);
    		GEM_BUG_ON(ring->emit + need_wrap > ring->size);
    		GEM_BUG_ON(!IS_ALIGNED(need_wrap, sizeof(u64)));
    
    		/* Fill the tail with MI_NOOP */
    		memset64(ring->vaddr + ring->emit, 0, need_wrap / sizeof(u64));
    		ring->space -= need_wrap;
    		ring->emit = 0;
    	}
    
    	GEM_BUG_ON(ring->emit > ring->size - bytes);
    	GEM_BUG_ON(ring->space < bytes);
    	cs = ring->vaddr + ring->emit;
    	GEM_DEBUG_EXEC(memset32(cs, POISON_INUSE, bytes / sizeof(*cs)));
    	ring->emit += bytes;
    	ring->space -= bytes;
    
    	return cs;
    }
    
    /* Align the ring tail to a cacheline boundary */
    int intel_ring_cacheline_align(struct i915_request *rq)
    {
    	int num_dwords;
    	void *cs;
    
    	num_dwords = (rq->ring->emit & (CACHELINE_BYTES - 1)) / sizeof(u32);
    	if (num_dwords == 0)
    		return 0;
    
    	num_dwords = CACHELINE_DWORDS - num_dwords;
    	GEM_BUG_ON(num_dwords & 1);
    
    	cs = intel_ring_begin(rq, num_dwords);
    	if (IS_ERR(cs))
    		return PTR_ERR(cs);
    
    	memset64(cs, (u64)MI_NOOP << 32 | MI_NOOP, num_dwords / 2);
    	intel_ring_advance(rq, cs);
    
    	GEM_BUG_ON(rq->ring->emit & (CACHELINE_BYTES - 1));
    	return 0;
    }
    
    static void gen6_bsd_submit_request(struct i915_request *request)
    {
    	struct drm_i915_private *dev_priv = request->i915;
    
    	intel_uncore_forcewake_get(dev_priv, FORCEWAKE_ALL);
    
           /* 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_FW(GEN6_BSD_SLEEP_PSMI_CONTROL,
    		      _MASKED_BIT_ENABLE(GEN6_BSD_SLEEP_MSG_DISABLE));
    
    	/* Clear the context id. Here be magic! */
    	I915_WRITE64_FW(GEN6_BSD_RNCID, 0x0);
    
    	/* Wait for the ring not to be idle, i.e. for it to wake up. */
    	if (__intel_wait_for_register_fw(dev_priv,
    					 GEN6_BSD_SLEEP_PSMI_CONTROL,
    					 GEN6_BSD_SLEEP_INDICATOR,
    					 0,
    					 1000, 0, NULL))
    		DRM_ERROR("timed out waiting for the BSD ring to wake up\n");
    
    	/* Now that the ring is fully powered up, update the tail */
    	i9xx_submit_request(request);
    
    	/* Let the ring send IDLE messages to the GT again,
    	 * and so let it sleep to conserve power when idle.
    	 */
    	I915_WRITE_FW(GEN6_BSD_SLEEP_PSMI_CONTROL,
    		      _MASKED_BIT_DISABLE(GEN6_BSD_SLEEP_MSG_DISABLE));
    
    	intel_uncore_forcewake_put(dev_priv, FORCEWAKE_ALL);
    }
    
    static int mi_flush_dw(struct i915_request *rq, u32 flags)
    {
    	u32 cmd, *cs;
    
    	cs = intel_ring_begin(rq, 4);
    	if (IS_ERR(cs))
    		return PTR_ERR(cs);
    
    	cmd = MI_FLUSH_DW;
    
    	/*
    	 * We always require a command barrier so that subsequent
    	 * commands, such as breadcrumb interrupts, are strictly ordered
    	 * wrt the contents of the write cache being flushed to memory
    	 * (and thus being coherent from the CPU).
    	 */
    	cmd |= MI_FLUSH_DW_STORE_INDEX | MI_FLUSH_DW_OP_STOREDW;
    
    	/*
    	 * Bspec vol 1c.3 - blitter engine command streamer:
    	 * "If ENABLED, all TLBs will be invalidated once the flush
    	 * operation is complete. This bit is only valid when the
    	 * Post-Sync Operation field is a value of 1h or 3h."
    	 */
    	cmd |= flags;
    
    	*cs++ = cmd;
    	*cs++ = I915_GEM_HWS_SCRATCH_ADDR | MI_FLUSH_DW_USE_GTT;
    	*cs++ = 0;
    	*cs++ = MI_NOOP;
    
    	intel_ring_advance(rq, cs);
    
    	return 0;
    }
    
    static int gen6_flush_dw(struct i915_request *rq, u32 mode, u32 invflags)
    {
    	return mi_flush_dw(rq, mode & EMIT_INVALIDATE ? invflags : 0);
    }
    
    static int gen6_bsd_ring_flush(struct i915_request *rq, u32 mode)
    {
    	return gen6_flush_dw(rq, mode, MI_INVALIDATE_TLB | MI_INVALIDATE_BSD);
    }
    
    static int
    hsw_emit_bb_start(struct i915_request *rq,
    		  u64 offset, u32 len,
    		  unsigned int dispatch_flags)
    {
    	u32 *cs;
    
    	cs = intel_ring_begin(rq, 2);
    	if (IS_ERR(cs))
    		return PTR_ERR(cs);
    
    	*cs++ = MI_BATCH_BUFFER_START | (dispatch_flags & I915_DISPATCH_SECURE ?
    		0 : MI_BATCH_PPGTT_HSW | MI_BATCH_NON_SECURE_HSW);
    	/* bit0-7 is the length on GEN6+ */
    	*cs++ = offset;
    	intel_ring_advance(rq, cs);
    
    	return 0;
    }
    
    static int
    gen6_emit_bb_start(struct i915_request *rq,
    		   u64 offset, u32 len,
    		   unsigned int dispatch_flags)
    {
    	u32 *cs;
    
    	cs = intel_ring_begin(rq, 2);
    	if (IS_ERR(cs))
    		return PTR_ERR(cs);
    
    	*cs++ = MI_BATCH_BUFFER_START | (dispatch_flags & I915_DISPATCH_SECURE ?
    		0 : MI_BATCH_NON_SECURE_I965);
    	/* bit0-7 is the length on GEN6+ */
    	*cs++ = offset;
    	intel_ring_advance(rq, cs);
    
    	return 0;
    }
    
    /* Blitter support (SandyBridge+) */
    
    static int gen6_ring_flush(struct i915_request *rq, u32 mode)
    {
    	return gen6_flush_dw(rq, mode, MI_INVALIDATE_TLB);
    }
    
    static void intel_ring_init_irq(struct drm_i915_private *dev_priv,
    				struct intel_engine_cs *engine)
    {
    	if (INTEL_GEN(dev_priv) >= 6) {
    		engine->irq_enable = gen6_irq_enable;
    		engine->irq_disable = gen6_irq_disable;
    	} else if (INTEL_GEN(dev_priv) >= 5) {
    		engine->irq_enable = gen5_irq_enable;
    		engine->irq_disable = gen5_irq_disable;
    	} else if (INTEL_GEN(dev_priv) >= 3) {
    		engine->irq_enable = i9xx_irq_enable;
    		engine->irq_disable = i9xx_irq_disable;
    	} else {
    		engine->irq_enable = i8xx_irq_enable;
    		engine->irq_disable = i8xx_irq_disable;
    	}
    }
    
    static void i9xx_set_default_submission(struct intel_engine_cs *engine)
    {
    	engine->submit_request = i9xx_submit_request;
    	engine->cancel_requests = cancel_requests;
    
    	engine->park = NULL;
    	engine->unpark = NULL;
    }
    
    static void gen6_bsd_set_default_submission(struct intel_engine_cs *engine)
    {
    	i9xx_set_default_submission(engine);
    	engine->submit_request = gen6_bsd_submit_request;
    }
    
    static void intel_ring_default_vfuncs(struct drm_i915_private *dev_priv,
    				      struct intel_engine_cs *engine)
    {
    	/* gen8+ are only supported with execlists */
    	GEM_BUG_ON(INTEL_GEN(dev_priv) >= 8);
    
    	intel_ring_init_irq(dev_priv, engine);
    
    	engine->init_hw = init_ring_common;
    	engine->reset.prepare = reset_prepare;
    	engine->reset.reset = reset_ring;
    	engine->reset.finish = reset_finish;
    
    	engine->cops = &ring_context_ops;
    	engine->request_alloc = ring_request_alloc;
    
    	/*
    	 * Using a global execution timeline; the previous final breadcrumb is
    	 * equivalent to our next initial bread so we can elide
    	 * engine->emit_init_breadcrumb().
    	 */
    	engine->emit_fini_breadcrumb = i9xx_emit_breadcrumb;
    	if (IS_GEN(dev_priv, 5))
    		engine->emit_fini_breadcrumb = gen5_emit_breadcrumb;
    
    	engine->set_default_submission = i9xx_set_default_submission;
    
    	if (INTEL_GEN(dev_priv) >= 6)
    		engine->emit_bb_start = gen6_emit_bb_start;
    	else if (INTEL_GEN(dev_priv) >= 4)
    		engine->emit_bb_start = i965_emit_bb_start;
    	else if (IS_I830(dev_priv) || IS_I845G(dev_priv))
    		engine->emit_bb_start = i830_emit_bb_start;
    	else
    		engine->emit_bb_start = i915_emit_bb_start;
    }
    
    int intel_init_render_ring_buffer(struct intel_engine_cs *engine)
    {
    	struct drm_i915_private *dev_priv = engine->i915;
    	int ret;
    
    	intel_ring_default_vfuncs(dev_priv, engine);
    
    	if (HAS_L3_DPF(dev_priv))
    		engine->irq_keep_mask = GT_RENDER_L3_PARITY_ERROR_INTERRUPT;
    
    	engine->irq_enable_mask = GT_RENDER_USER_INTERRUPT;
    
    	if (INTEL_GEN(dev_priv) >= 7) {
    		engine->init_context = intel_rcs_ctx_init;
    		engine->emit_flush = gen7_render_ring_flush;
    		engine->emit_fini_breadcrumb = gen7_rcs_emit_breadcrumb;
    	} else if (IS_GEN(dev_priv, 6)) {
    		engine->init_context = intel_rcs_ctx_init;
    		engine->emit_flush = gen6_render_ring_flush;
    		engine->emit_fini_breadcrumb = gen6_rcs_emit_breadcrumb;
    	} else if (IS_GEN(dev_priv, 5)) {
    		engine->emit_flush = gen4_render_ring_flush;
    	} else {
    		if (INTEL_GEN(dev_priv) < 4)
    			engine->emit_flush = gen2_render_ring_flush;
    		else
    			engine->emit_flush = gen4_render_ring_flush;
    		engine->irq_enable_mask = I915_USER_INTERRUPT;
    	}
    
    	if (IS_HASWELL(dev_priv))
    		engine->emit_bb_start = hsw_emit_bb_start;
    
    	engine->init_hw = init_render_ring;
    
    	ret = intel_init_ring_buffer(engine);
    	if (ret)
    		return ret;
    
    	return 0;
    }
    
    int intel_init_bsd_ring_buffer(struct intel_engine_cs *engine)
    {
    	struct drm_i915_private *dev_priv = engine->i915;
    
    	intel_ring_default_vfuncs(dev_priv, engine);
    
    	if (INTEL_GEN(dev_priv) >= 6) {
    		/* gen6 bsd needs a special wa for tail updates */
    		if (IS_GEN(dev_priv, 6))
    			engine->set_default_submission = gen6_bsd_set_default_submission;
    		engine->emit_flush = gen6_bsd_ring_flush;
    		engine->irq_enable_mask = GT_BSD_USER_INTERRUPT;
    
    		if (IS_GEN(dev_priv, 6))
    			engine->emit_fini_breadcrumb = gen6_xcs_emit_breadcrumb;
    		else
    			engine->emit_fini_breadcrumb = gen7_xcs_emit_breadcrumb;
    	} else {
    		engine->emit_flush = bsd_ring_flush;
    		if (IS_GEN(dev_priv, 5))
    			engine->irq_enable_mask = ILK_BSD_USER_INTERRUPT;
    		else
    			engine->irq_enable_mask = I915_BSD_USER_INTERRUPT;
    	}
    
    	return intel_init_ring_buffer(engine);
    }
    
    int intel_init_blt_ring_buffer(struct intel_engine_cs *engine)
    {
    	struct drm_i915_private *dev_priv = engine->i915;
    
    	GEM_BUG_ON(INTEL_GEN(dev_priv) < 6);
    
    	intel_ring_default_vfuncs(dev_priv, engine);
    
    	engine->emit_flush = gen6_ring_flush;
    	engine->irq_enable_mask = GT_BLT_USER_INTERRUPT;
    
    	if (IS_GEN(dev_priv, 6))
    		engine->emit_fini_breadcrumb = gen6_xcs_emit_breadcrumb;
    	else
    		engine->emit_fini_breadcrumb = gen7_xcs_emit_breadcrumb;
    
    	return intel_init_ring_buffer(engine);
    }
    
    int intel_init_vebox_ring_buffer(struct intel_engine_cs *engine)
    {
    	struct drm_i915_private *dev_priv = engine->i915;
    
    	GEM_BUG_ON(INTEL_GEN(dev_priv) < 7);
    
    	intel_ring_default_vfuncs(dev_priv, engine);
    
    	engine->emit_flush = gen6_ring_flush;
    	engine->irq_enable_mask = PM_VEBOX_USER_INTERRUPT;
    	engine->irq_enable = hsw_vebox_irq_enable;
    	engine->irq_disable = hsw_vebox_irq_disable;
    
    	engine->emit_fini_breadcrumb = gen7_xcs_emit_breadcrumb;
    
    	return intel_init_ring_buffer(engine);
    }