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/*

 * Copyright © 2010 Daniel Vetter

 *

 * 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.

 *

 */

#define AGP_NORMAL_MEMORY 0

#define AGP_USER_TYPES (1 << 16)

#define AGP_USER_MEMORY (AGP_USER_TYPES)

#define AGP_USER_CACHED_MEMORY (AGP_USER_TYPES + 1)

#include 

#include 

#include "i915_drv.h"

#include "i915_trace.h"

#include "intel_drv.h"

typedef uint32_t gen6_gtt_pte_t;

/* PPGTT stuff */

#define GEN6_GTT_ADDR_ENCODE(addr)	((addr) | (((addr) >> 28) & 0xff0))

#define GEN6_PDE_VALID			(1 << 0)

/* gen6+ has bit 11-4 for physical addr bit 39-32 */

#define GEN6_PDE_ADDR_ENCODE(addr)	GEN6_GTT_ADDR_ENCODE(addr)

#define GEN6_PTE_VALID			(1 << 0)

#define GEN6_PTE_UNCACHED		(1 << 1)

#define HSW_PTE_UNCACHED		(0)

#define GEN6_PTE_CACHE_LLC		(2 << 1)

#define GEN6_PTE_CACHE_LLC_MLC		(3 << 1)

#define GEN6_PTE_ADDR_ENCODE(addr)	GEN6_GTT_ADDR_ENCODE(addr)

static inline gen6_gtt_pte_t gen6_pte_encode(struct drm_device *dev,

				   dma_addr_t addr,

				   enum i915_cache_level level)

{

	gen6_gtt_pte_t pte = GEN6_PTE_VALID;

	pte |= GEN6_PTE_ADDR_ENCODE(addr);

	switch (level) {

	case I915_CACHE_LLC_MLC:

		/* Haswell doesn't set L3 this way */

		if (IS_HASWELL(dev))

			pte |= GEN6_PTE_CACHE_LLC;

		else

			pte |= GEN6_PTE_CACHE_LLC_MLC;

		break;

	case I915_CACHE_LLC:

		pte |= GEN6_PTE_CACHE_LLC;

		break;

	case I915_CACHE_NONE:

		if (IS_HASWELL(dev))

			pte |= HSW_PTE_UNCACHED;

		else

			pte |= GEN6_PTE_UNCACHED;

		break;

	default:

		BUG();

	}

	return pte;

}

static int gen6_ppgtt_enable(struct drm_device *dev)

{

	drm_i915_private_t *dev_priv = dev->dev_private;

	uint32_t pd_offset;

	struct intel_ring_buffer *ring;

	struct i915_hw_ppgtt *ppgtt = dev_priv->mm.aliasing_ppgtt;

	gen6_gtt_pte_t __iomem *pd_addr;

	uint32_t pd_entry;

	int i;

	pd_addr = (gen6_gtt_pte_t __iomem*)dev_priv->gtt.gsm +

		ppgtt->pd_offset / sizeof(gen6_gtt_pte_t);

	for (i = 0; i < ppgtt->num_pd_entries; i++) {

		dma_addr_t pt_addr;

		pt_addr = ppgtt->pt_dma_addr[i];

		pd_entry = GEN6_PDE_ADDR_ENCODE(pt_addr);

		pd_entry |= GEN6_PDE_VALID;

		writel(pd_entry, pd_addr + i);

	}

	readl(pd_addr);

	pd_offset = ppgtt->pd_offset;

	pd_offset /= 64; /* in cachelines, */

	pd_offset <<= 16;

	if (INTEL_INFO(dev)->gen == 6) {

		uint32_t ecochk, gab_ctl, ecobits;

		ecobits = I915_READ(GAC_ECO_BITS);

		I915_WRITE(GAC_ECO_BITS, ecobits | ECOBITS_SNB_BIT |

					 ECOBITS_PPGTT_CACHE64B);

		gab_ctl = I915_READ(GAB_CTL);

		I915_WRITE(GAB_CTL, gab_ctl | GAB_CTL_CONT_AFTER_PAGEFAULT);

		ecochk = I915_READ(GAM_ECOCHK);

		I915_WRITE(GAM_ECOCHK, ecochk | ECOCHK_SNB_BIT |

				       ECOCHK_PPGTT_CACHE64B);

		I915_WRITE(GFX_MODE, _MASKED_BIT_ENABLE(GFX_PPGTT_ENABLE));

	} else if (INTEL_INFO(dev)->gen >= 7) {

		uint32_t ecochk, ecobits;

		ecobits = I915_READ(GAC_ECO_BITS);

		I915_WRITE(GAC_ECO_BITS, ecobits | ECOBITS_PPGTT_CACHE64B);

		ecochk = I915_READ(GAM_ECOCHK);

		if (IS_HASWELL(dev)) {

			ecochk |= ECOCHK_PPGTT_WB_HSW;

		} else {

			ecochk |= ECOCHK_PPGTT_LLC_IVB;

			ecochk &= ~ECOCHK_PPGTT_GFDT_IVB;

		}

		I915_WRITE(GAM_ECOCHK, ecochk);

		/* GFX_MODE is per-ring on gen7+ */

	}

	for_each_ring(ring, dev_priv, i) {

		if (INTEL_INFO(dev)->gen >= 7)

			I915_WRITE(RING_MODE_GEN7(ring),

				   _MASKED_BIT_ENABLE(GFX_PPGTT_ENABLE));

		I915_WRITE(RING_PP_DIR_DCLV(ring), PP_DIR_DCLV_2G);

		I915_WRITE(RING_PP_DIR_BASE(ring), pd_offset);

	}

	return 0;

}

/* PPGTT support for Sandybdrige/Gen6 and later */

static void gen6_ppgtt_clear_range(struct i915_hw_ppgtt *ppgtt,

				   unsigned first_entry,

				   unsigned num_entries)

{

	gen6_gtt_pte_t *pt_vaddr, scratch_pte;

	unsigned act_pt = first_entry / I915_PPGTT_PT_ENTRIES;

	unsigned first_pte = first_entry % I915_PPGTT_PT_ENTRIES;

	unsigned last_pte, i;

	scratch_pte = gen6_pte_encode(ppgtt->dev,

				      ppgtt->scratch_page_dma_addr,

				 I915_CACHE_LLC);

    pt_vaddr = AllocKernelSpace(4096);

    if(pt_vaddr == NULL)

        return;

	while (num_entries) {

            last_pte = first_pte + num_entries;

            if (last_pte > I915_PPGTT_PT_ENTRIES)

                last_pte = I915_PPGTT_PT_ENTRIES;

            MapPage(pt_vaddr,(addr_t)(ppgtt->pt_pages[act_pt]), 3);

            for (i = first_pte; i < last_pte; i++)

                pt_vaddr[i] = scratch_pte;

            num_entries -= last_pte - first_pte;

            first_pte = 0;

            act_pt++;

    };

    FreeKernelSpace(pt_vaddr);

}

static void gen6_ppgtt_insert_entries(struct i915_hw_ppgtt *ppgtt,

				      struct sg_table *pages,

				      unsigned first_entry,

				      enum i915_cache_level cache_level)

{

	gen6_gtt_pte_t *pt_vaddr;

	unsigned act_pt = first_entry / I915_PPGTT_PT_ENTRIES;

	unsigned act_pte = first_entry % I915_PPGTT_PT_ENTRIES;

	struct sg_page_iter sg_iter;

	dma_addr_t page_addr;

    pt_vaddr = AllocKernelSpace(4096);

    if(pt_vaddr == NULL)

        return;

    MapPage(pt_vaddr,(addr_t)(ppgtt->pt_pages[act_pt]), 3);

	for_each_sg_page(pages->sgl, &sg_iter, pages->nents, 0) {

		dma_addr_t page_addr;

		page_addr = sg_page_iter_dma_address(&sg_iter);

		pt_vaddr[act_pte] = gen6_pte_encode(ppgtt->dev, page_addr,

						      cache_level);

		if (++act_pte == I915_PPGTT_PT_ENTRIES) {

			act_pt++;

    		MapPage(pt_vaddr,(addr_t)(ppgtt->pt_pages[act_pt]), 3);

			act_pte = 0;

		}

        }

        FreeKernelSpace(pt_vaddr);

}

static void gen6_ppgtt_cleanup(struct i915_hw_ppgtt *ppgtt)

{

	int i;

	if (ppgtt->pt_dma_addr) {

		for (i = 0; i < ppgtt->num_pd_entries; i++)

			pci_unmap_page(ppgtt->dev->pdev,

				       ppgtt->pt_dma_addr[i],

				       4096, PCI_DMA_BIDIRECTIONAL);

	}

	kfree(ppgtt->pt_dma_addr);

	for (i = 0; i < ppgtt->num_pd_entries; i++)

		__free_page(ppgtt->pt_pages[i]);

	kfree(ppgtt->pt_pages);

	kfree(ppgtt);

}

static int gen6_ppgtt_init(struct i915_hw_ppgtt *ppgtt)

{

	struct drm_device *dev = ppgtt->dev;

	struct drm_i915_private *dev_priv = dev->dev_private;

	unsigned first_pd_entry_in_global_pt;

	int i;

	int ret = -ENOMEM;

	/* ppgtt PDEs reside in the global gtt pagetable, which has 512*1024

	 * entries. For aliasing ppgtt support we just steal them at the end for

	 * now. */

       first_pd_entry_in_global_pt = gtt_total_entries(dev_priv->gtt);

	ppgtt->num_pd_entries = I915_PPGTT_PD_ENTRIES;

	ppgtt->enable = gen6_ppgtt_enable;

	ppgtt->clear_range = gen6_ppgtt_clear_range;

	ppgtt->insert_entries = gen6_ppgtt_insert_entries;

	ppgtt->cleanup = gen6_ppgtt_cleanup;

	ppgtt->pt_pages = kzalloc(sizeof(struct page *)*ppgtt->num_pd_entries,

				  GFP_KERNEL);

	if (!ppgtt->pt_pages)

		return -ENOMEM;

	for (i = 0; i < ppgtt->num_pd_entries; i++) {

		ppgtt->pt_pages[i] = alloc_page(GFP_KERNEL);

		if (!ppgtt->pt_pages[i])

			goto err_pt_alloc;

	}

	ppgtt->pt_dma_addr = kzalloc(sizeof(dma_addr_t) *ppgtt->num_pd_entries,

					     GFP_KERNEL);

		if (!ppgtt->pt_dma_addr)

			goto err_pt_alloc;

		for (i = 0; i < ppgtt->num_pd_entries; i++) {

			dma_addr_t pt_addr;

		pt_addr = pci_map_page(dev->pdev, ppgtt->pt_pages[i], 0, 4096,

					       PCI_DMA_BIDIRECTIONAL);

			ppgtt->pt_dma_addr[i] = pt_addr;

		}

	ppgtt->clear_range(ppgtt, 0,

			       ppgtt->num_pd_entries*I915_PPGTT_PT_ENTRIES);

	ppgtt->pd_offset = first_pd_entry_in_global_pt * sizeof(gen6_gtt_pte_t);

	return 0;

err_pd_pin:

	if (ppgtt->pt_dma_addr) {

		for (i--; i >= 0; i--)

			pci_unmap_page(dev->pdev, ppgtt->pt_dma_addr[i],

				       4096, PCI_DMA_BIDIRECTIONAL);

	}

err_pt_alloc:

	kfree(ppgtt->pt_dma_addr);

	for (i = 0; i < ppgtt->num_pd_entries; i++) {

		if (ppgtt->pt_pages[i])

			__free_page(ppgtt->pt_pages[i]);

	}

	kfree(ppgtt->pt_pages);

	return ret;

}

static int i915_gem_init_aliasing_ppgtt(struct drm_device *dev)

{

	struct drm_i915_private *dev_priv = dev->dev_private;

	struct i915_hw_ppgtt *ppgtt;

	int ret;

	ppgtt = kzalloc(sizeof(*ppgtt), GFP_KERNEL);

	if (!ppgtt)

		return -ENOMEM;

	ppgtt->dev = dev;

	ppgtt->scratch_page_dma_addr = dev_priv->gtt.scratch_page_dma;

	if (INTEL_INFO(dev)->gen < 8)

	ret = gen6_ppgtt_init(ppgtt);

	else

		BUG();

	if (ret)

	kfree(ppgtt);

	else

		dev_priv->mm.aliasing_ppgtt = ppgtt;

	return ret;

}

void i915_gem_cleanup_aliasing_ppgtt(struct drm_device *dev)

{

	struct drm_i915_private *dev_priv = dev->dev_private;

	struct i915_hw_ppgtt *ppgtt = dev_priv->mm.aliasing_ppgtt;

	if (!ppgtt)

		return;

	ppgtt->cleanup(ppgtt);

	dev_priv->mm.aliasing_ppgtt = NULL;

}

void i915_ppgtt_bind_object(struct i915_hw_ppgtt *ppgtt,

			    struct drm_i915_gem_object *obj,

			    enum i915_cache_level cache_level)

{

	ppgtt->insert_entries(ppgtt, obj->pages,

				     obj->gtt_space->start >> PAGE_SHIFT,

				     cache_level);

}

void i915_ppgtt_unbind_object(struct i915_hw_ppgtt *ppgtt,

			      struct drm_i915_gem_object *obj)

{

	ppgtt->clear_range(ppgtt,

			       obj->gtt_space->start >> PAGE_SHIFT,

			       obj->base.size >> PAGE_SHIFT);

}

extern int intel_iommu_gfx_mapped;

/* Certain Gen5 chipsets require require idling the GPU before

 * unmapping anything from the GTT when VT-d is enabled.

 */

static inline bool needs_idle_maps(struct drm_device *dev)

{

#ifdef CONFIG_INTEL_IOMMU

	/* Query intel_iommu to see if we need the workaround. Presumably that

	 * was loaded first.

	 */

	if (IS_GEN5(dev) && IS_MOBILE(dev) && intel_iommu_gfx_mapped)

		return true;

#endif

	return false;

}

static bool do_idling(struct drm_i915_private *dev_priv)

{

	bool ret = dev_priv->mm.interruptible;

	if (unlikely(dev_priv->gtt.do_idle_maps)) {

		dev_priv->mm.interruptible = false;

		if (i915_gpu_idle(dev_priv->dev)) {

			DRM_ERROR("Couldn't idle GPU\n");

			/* Wait a bit, in hopes it avoids the hang */

			udelay(10);

		}

	}

	return ret;

}

static void undo_idling(struct drm_i915_private *dev_priv, bool interruptible)

{

	if (unlikely(dev_priv->gtt.do_idle_maps))

		dev_priv->mm.interruptible = interruptible;

}

void i915_gem_restore_gtt_mappings(struct drm_device *dev)

{

	struct drm_i915_private *dev_priv = dev->dev_private;

	struct drm_i915_gem_object *obj;

	/* First fill our portion of the GTT with scratch pages */

	dev_priv->gtt.gtt_clear_range(dev, dev_priv->gtt.start / PAGE_SIZE,

				      dev_priv->gtt.total / PAGE_SIZE);

	list_for_each_entry(obj, &dev_priv->mm.bound_list, gtt_list) {

		i915_gem_clflush_object(obj);

		i915_gem_gtt_bind_object(obj, obj->cache_level);

	}

	i915_gem_chipset_flush(dev);

}

int i915_gem_gtt_prepare_object(struct drm_i915_gem_object *obj)

{

	if (obj->has_dma_mapping)

		return 0;

	if (!dma_map_sg(&obj->base.dev->pdev->dev,

			obj->pages->sgl, obj->pages->nents,

			PCI_DMA_BIDIRECTIONAL))

		return -ENOSPC;

	return 0;

}

/*

 * Binds an object into the global gtt with the specified cache level. The object

 * will be accessible to the GPU via commands whose operands reference offsets

 * within the global GTT as well as accessible by the GPU through the GMADR

 * mapped BAR (dev_priv->mm.gtt->gtt).

 */

static void gen6_ggtt_insert_entries(struct drm_device *dev,

				     struct sg_table *st,

				     unsigned int first_entry,

				  enum i915_cache_level level)

{

	struct drm_i915_private *dev_priv = dev->dev_private;

	gen6_gtt_pte_t __iomem *gtt_entries =

		(gen6_gtt_pte_t __iomem *)dev_priv->gtt.gsm + first_entry;

	int i = 0;

	struct sg_page_iter sg_iter;

	dma_addr_t addr;

	for_each_sg_page(st->sgl, &sg_iter, st->nents, 0) {

		addr = sg_page_iter_dma_address(&sg_iter);

		iowrite32(gen6_pte_encode(dev, addr, level), >t_entries[i]);

			i++;

		}

	/* XXX: This serves as a posting read to make sure that the PTE has

	 * actually been updated. There is some concern that even though

	 * registers and PTEs are within the same BAR that they are potentially

	 * of NUMA access patterns. Therefore, even with the way we assume

	 * hardware should work, we must keep this posting read for paranoia.

	 */

	if (i != 0)

		WARN_ON(readl(>t_entries[i-1])

			!= gen6_pte_encode(dev, addr, level));

	/* This next bit makes the above posting read even more important. We

	 * want to flush the TLBs only after we're certain all the PTE updates

	 * have finished.

	 */

	I915_WRITE(GFX_FLSH_CNTL_GEN6, GFX_FLSH_CNTL_EN);

	POSTING_READ(GFX_FLSH_CNTL_GEN6);

}

static void gen6_ggtt_clear_range(struct drm_device *dev,

				  unsigned int first_entry,

				  unsigned int num_entries)

{

	struct drm_i915_private *dev_priv = dev->dev_private;

	gen6_gtt_pte_t scratch_pte, __iomem *gtt_base =

		(gen6_gtt_pte_t __iomem *) dev_priv->gtt.gsm + first_entry;

	const int max_entries = gtt_total_entries(dev_priv->gtt) - first_entry;

	int i;

//   if (WARN(num_entries > max_entries,

//        "First entry = %d; Num entries = %d (max=%d)\n",

//        first_entry, num_entries, max_entries))

   if (num_entries > max_entries)

		num_entries = max_entries;

	scratch_pte = gen6_pte_encode(dev, dev_priv->gtt.scratch_page_dma,

				      I915_CACHE_LLC);

	for (i = 0; i < num_entries; i++)

		iowrite32(scratch_pte, >t_base[i]);

	readl(gtt_base);

}

static void i915_ggtt_insert_entries(struct drm_device *dev,

				     struct sg_table *st,

				     unsigned int pg_start,

				     enum i915_cache_level cache_level)

{

	unsigned int flags = (cache_level == I915_CACHE_NONE) ?

		AGP_USER_MEMORY : AGP_USER_CACHED_MEMORY;

	intel_gtt_insert_sg_entries(st, pg_start, flags);

}

static void i915_ggtt_clear_range(struct drm_device *dev,

				  unsigned int first_entry,

				  unsigned int num_entries)

{

	intel_gtt_clear_range(first_entry, num_entries);

}

void i915_gem_gtt_bind_object(struct drm_i915_gem_object *obj,

				enum i915_cache_level cache_level)

{

	struct drm_device *dev = obj->base.dev;

	struct drm_i915_private *dev_priv = dev->dev_private;

	dev_priv->gtt.gtt_insert_entries(dev, obj->pages,

					    obj->gtt_space->start >> PAGE_SHIFT,

					 cache_level);

	obj->has_global_gtt_mapping = 1;

}

void i915_gem_gtt_unbind_object(struct drm_i915_gem_object *obj)

{

	struct drm_device *dev = obj->base.dev;

	struct drm_i915_private *dev_priv = dev->dev_private;

	dev_priv->gtt.gtt_clear_range(obj->base.dev,

			      obj->gtt_space->start >> PAGE_SHIFT,

			      obj->base.size >> PAGE_SHIFT);

	obj->has_global_gtt_mapping = 0;

}

void i915_gem_gtt_finish_object(struct drm_i915_gem_object *obj)

{

	struct drm_device *dev = obj->base.dev;

	struct drm_i915_private *dev_priv = dev->dev_private;

	bool interruptible;

	interruptible = do_idling(dev_priv);

	if (!obj->has_dma_mapping)

		dma_unmap_sg(&dev->pdev->dev,

			     obj->pages->sgl, obj->pages->nents,

			     PCI_DMA_BIDIRECTIONAL);

	undo_idling(dev_priv, interruptible);

}

static void i915_gtt_color_adjust(struct drm_mm_node *node,

				  unsigned long color,

				  unsigned long *start,

				  unsigned long *end)

{

	if (node->color != color)

		*start += 4096;

	if (!list_empty(&node->node_list)) {

		node = list_entry(node->node_list.next,

				  struct drm_mm_node,

				  node_list);

		if (node->allocated && node->color != color)

			*end -= 4096;

	}

}

void i915_gem_setup_global_gtt(struct drm_device *dev,

			      unsigned long start,

			      unsigned long mappable_end,

			      unsigned long end)

{

	/* Let GEM Manage all of the aperture.

	 *

	 * However, leave one page at the end still bound to the scratch page.

	 * There are a number of places where the hardware apparently prefetches

	 * past the end of the object, and we've seen multiple hangs with the

	 * GPU head pointer stuck in a batchbuffer bound at the last page of the

	 * aperture.  One page should be enough to keep any prefetching inside

	 * of the aperture.

	 */

	drm_i915_private_t *dev_priv = dev->dev_private;

	struct drm_mm_node *entry;

	struct drm_i915_gem_object *obj;

	unsigned long hole_start, hole_end;

	BUG_ON(mappable_end > end);

	/* Subtract the guard page ... */

	drm_mm_init(&dev_priv->mm.gtt_space, start, end - start - PAGE_SIZE);

	if (!HAS_LLC(dev))

		dev_priv->mm.gtt_space.color_adjust = i915_gtt_color_adjust;

	/* Mark any preallocated objects as occupied */

	list_for_each_entry(obj, &dev_priv->mm.bound_list, gtt_list) {

		DRM_DEBUG_KMS("reserving preallocated space: %x + %zx\n",

			      obj->gtt_offset, obj->base.size);

		BUG_ON(obj->gtt_space != I915_GTT_RESERVED);

		obj->gtt_space = drm_mm_create_block(&dev_priv->mm.gtt_space,

						     obj->gtt_offset,

						     obj->base.size,

						     false);

		obj->has_global_gtt_mapping = 1;

	}

	dev_priv->gtt.start = start;

	dev_priv->gtt.total = end - start;

	/* Clear any non-preallocated blocks */

	drm_mm_for_each_hole(entry, &dev_priv->mm.gtt_space,

			     hole_start, hole_end) {

		DRM_DEBUG_KMS("clearing unused GTT space: [%lx, %lx]\n",

			      hole_start, hole_end);

		dev_priv->gtt.gtt_clear_range(dev, hole_start / PAGE_SIZE,

					      (hole_end-hole_start) / PAGE_SIZE);

	}

	/* And finally clear the reserved guard page */

	dev_priv->gtt.gtt_clear_range(dev, end / PAGE_SIZE - 1, 1);

}

static bool

intel_enable_ppgtt(struct drm_device *dev)

{

	if (i915_enable_ppgtt >= 0)

		return i915_enable_ppgtt;

#ifdef CONFIG_INTEL_IOMMU

	/* Disable ppgtt on SNB if VT-d is on. */

	if (INTEL_INFO(dev)->gen == 6 && intel_iommu_gfx_mapped)

		return false;

#endif

	return true;

}

void i915_gem_init_global_gtt(struct drm_device *dev)

{

	struct drm_i915_private *dev_priv = dev->dev_private;

	unsigned long gtt_size, mappable_size;

	gtt_size = dev_priv->gtt.total;

	mappable_size = dev_priv->gtt.mappable_end;

#if 0

	if (intel_enable_ppgtt(dev) && HAS_ALIASING_PPGTT(dev)) {

		int ret;

		if (INTEL_INFO(dev)->gen <= 7) {

		/* PPGTT pdes are stolen from global gtt ptes, so shrink the

		 * aperture accordingly when using aliasing ppgtt. */

        gtt_size -= I915_PPGTT_PD_ENTRIES*PAGE_SIZE;

		}

//        gtt_size -= LFB_SIZE;

        i915_gem_setup_global_gtt(dev, LFB_SIZE, mappable_size, gtt_size);

		ret = i915_gem_init_aliasing_ppgtt(dev);

		if (!ret)

			return;

		DRM_ERROR("Aliased PPGTT setup failed %d\n", ret);

		drm_mm_takedown(&dev_priv->mm.gtt_space);

		gtt_size += I915_PPGTT_PD_ENTRIES*PAGE_SIZE;

}

#endif

    i915_gem_setup_global_gtt(dev, LFB_SIZE, mappable_size, gtt_size);

}

static int setup_scratch_page(struct drm_device *dev)

{

	struct drm_i915_private *dev_priv = dev->dev_private;

	struct page *page;

	dma_addr_t dma_addr;

	page = alloc_page(GFP_KERNEL | GFP_DMA32 | __GFP_ZERO);

	if (page == NULL)

		return -ENOMEM;

	get_page(page);

	set_pages_uc(page, 1);

#ifdef CONFIG_INTEL_IOMMU

	dma_addr = pci_map_page(dev->pdev, page, 0, PAGE_SIZE,

				PCI_DMA_BIDIRECTIONAL);

	if (pci_dma_mapping_error(dev->pdev, dma_addr))

		return -EINVAL;

#else

	dma_addr = page_to_phys(page);

#endif

	dev_priv->gtt.scratch_page = page;

	dev_priv->gtt.scratch_page_dma = dma_addr;

	return 0;

}

static void teardown_scratch_page(struct drm_device *dev)

{

	struct drm_i915_private *dev_priv = dev->dev_private;

	set_pages_wb(dev_priv->gtt.scratch_page, 1);

	pci_unmap_page(dev->pdev, dev_priv->gtt.scratch_page_dma,

		       PAGE_SIZE, PCI_DMA_BIDIRECTIONAL);

	put_page(dev_priv->gtt.scratch_page);

	__free_page(dev_priv->gtt.scratch_page);

}

static inline unsigned int gen6_get_total_gtt_size(u16 snb_gmch_ctl)

{

	snb_gmch_ctl >>= SNB_GMCH_GGMS_SHIFT;

	snb_gmch_ctl &= SNB_GMCH_GGMS_MASK;

	return snb_gmch_ctl << 20;

}

static inline size_t gen6_get_stolen_size(u16 snb_gmch_ctl)

{

	snb_gmch_ctl >>= SNB_GMCH_GMS_SHIFT;

	snb_gmch_ctl &= SNB_GMCH_GMS_MASK;

	return snb_gmch_ctl << 25; /* 32 MB units */

}

static int gen6_gmch_probe(struct drm_device *dev,

			   size_t *gtt_total,

			   size_t *stolen,

			   phys_addr_t *mappable_base,

			   unsigned long *mappable_end)

{

	struct drm_i915_private *dev_priv = dev->dev_private;

	phys_addr_t gtt_bus_addr;

	unsigned int gtt_size;

	u16 snb_gmch_ctl;

	int ret;

	*mappable_base = pci_resource_start(dev->pdev, 2);

	*mappable_end = pci_resource_len(dev->pdev, 2);

	/* 64/512MB is the current min/max we actually know of, but this is just

	 * a coarse sanity check.

	 */

	if ((*mappable_end < (64<<20) || (*mappable_end > (512<<20)))) {

		DRM_ERROR("Unknown GMADR size (%lx)\n",

			  dev_priv->gtt.mappable_end);

		return -ENXIO;

		}

	if (!pci_set_dma_mask(dev->pdev, DMA_BIT_MASK(40)))

		pci_set_consistent_dma_mask(dev->pdev, DMA_BIT_MASK(40));

	pci_read_config_word(dev->pdev, SNB_GMCH_CTRL, &snb_gmch_ctl);

	gtt_size = gen6_get_total_gtt_size(snb_gmch_ctl);

		*stolen = gen6_get_stolen_size(snb_gmch_ctl);

	*gtt_total = (gtt_size / sizeof(gen6_gtt_pte_t)) << PAGE_SHIFT;

	/* For Modern GENs the PTEs and register space are split in the BAR */

	gtt_bus_addr = pci_resource_start(dev->pdev, 0) +

		(pci_resource_len(dev->pdev, 0) / 2);

	dev_priv->gtt.gsm = ioremap_wc(gtt_bus_addr, gtt_size);

	if (!dev_priv->gtt.gsm) {

		DRM_ERROR("Failed to map the gtt page table\n");

		return -ENOMEM;

	}

	ret = setup_scratch_page(dev);

	if (ret)

		DRM_ERROR("Scratch setup failed\n");

	dev_priv->gtt.gtt_clear_range = gen6_ggtt_clear_range;

	dev_priv->gtt.gtt_insert_entries = gen6_ggtt_insert_entries;

	return ret;

}

static void gen6_gmch_remove(struct drm_device *dev)

{

	struct drm_i915_private *dev_priv = dev->dev_private;

	iounmap(dev_priv->gtt.gsm);

	teardown_scratch_page(dev_priv->dev);

}

static int i915_gmch_probe(struct drm_device *dev,

			   size_t *gtt_total,

			   size_t *stolen,

			   phys_addr_t *mappable_base,

			   unsigned long *mappable_end)

{

	struct drm_i915_private *dev_priv = dev->dev_private;

	int ret;

	ret = intel_gmch_probe(dev_priv->bridge_dev, dev_priv->dev->pdev, NULL);

	if (!ret) {

		DRM_ERROR("failed to set up gmch\n");

		return -EIO;

	}

	intel_gtt_get(gtt_total, stolen, mappable_base, mappable_end);

	dev_priv->gtt.do_idle_maps = needs_idle_maps(dev_priv->dev);

	dev_priv->gtt.gtt_clear_range = i915_ggtt_clear_range;

	dev_priv->gtt.gtt_insert_entries = i915_ggtt_insert_entries;

	return 0;

}

static void i915_gmch_remove(struct drm_device *dev)

{

//   intel_gmch_remove();

}

int i915_gem_gtt_init(struct drm_device *dev)

{

	struct drm_i915_private *dev_priv = dev->dev_private;

	struct i915_gtt *gtt = &dev_priv->gtt;

	int ret;

	if (INTEL_INFO(dev)->gen <= 5) {

		dev_priv->gtt.gtt_probe = i915_gmch_probe;

		dev_priv->gtt.gtt_remove = i915_gmch_remove;

	} else {

		dev_priv->gtt.gtt_probe = gen6_gmch_probe;

		dev_priv->gtt.gtt_remove = gen6_gmch_remove;

	}

	ret = dev_priv->gtt.gtt_probe(dev, &dev_priv->gtt.total,

				     &dev_priv->gtt.stolen_size,

				     >t->mappable_base,

				     >t->mappable_end);

	if (ret)

	return ret;

	/* GMADR is the PCI mmio aperture into the global GTT. */

	DRM_INFO("Memory usable by graphics device = %zdM\n",

		 dev_priv->gtt.total >> 20);

	DRM_DEBUG_DRIVER("GMADR size = %ldM\n",

			 dev_priv->gtt.mappable_end >> 20);

	DRM_DEBUG_DRIVER("GTT stolen size = %zdM\n",

			 dev_priv->gtt.stolen_size >> 20);

	return 0;

}

struct scatterlist *sg_next(struct scatterlist *sg)

{

    if (sg_is_last(sg))

        return NULL;

    sg++;

    if (unlikely(sg_is_chain(sg)))

            sg = sg_chain_ptr(sg);

    return sg;

}

void __sg_free_table(struct sg_table *table, unsigned int max_ents,

                     sg_free_fn *free_fn)

{

    struct scatterlist *sgl, *next;

    if (unlikely(!table->sgl))

            return;

    sgl = table->sgl;

    while (table->orig_nents) {

        unsigned int alloc_size = table->orig_nents;

        unsigned int sg_size;

        /*

         * If we have more than max_ents segments left,

         * then assign 'next' to the sg table after the current one.

         * sg_size is then one less than alloc size, since the last

         * element is the chain pointer.

         */

        if (alloc_size > max_ents) {

                next = sg_chain_ptr(&sgl[max_ents - 1]);

                alloc_size = max_ents;

                sg_size = alloc_size - 1;

        } else {

                sg_size = alloc_size;

                next = NULL;

        }

        table->orig_nents -= sg_size;

        kfree(sgl);

        sgl = next;

    }

    table->sgl = NULL;

}

void sg_free_table(struct sg_table *table)

{

    __sg_free_table(table, SG_MAX_SINGLE_ALLOC, NULL);

}

int sg_alloc_table(struct sg_table *table, unsigned int nents, gfp_t gfp_mask)

{

    struct scatterlist *sg, *prv;

    unsigned int left;

    unsigned int max_ents = SG_MAX_SINGLE_ALLOC;

#ifndef ARCH_HAS_SG_CHAIN

    BUG_ON(nents > max_ents);

#endif

    memset(table, 0, sizeof(*table));

    left = nents;

    prv = NULL;

    do {

        unsigned int sg_size, alloc_size = left;

        if (alloc_size > max_ents) {

                alloc_size = max_ents;

                sg_size = alloc_size - 1;

        } else

                sg_size = alloc_size;

        left -= sg_size;

        sg = kmalloc(alloc_size * sizeof(struct scatterlist), gfp_mask);

        if (unlikely(!sg)) {

                /*

                 * Adjust entry count to reflect that the last

                 * entry of the previous table won't be used for

                 * linkage.  Without this, sg_kfree() may get

                 * confused.

                 */

                if (prv)

                        table->nents = ++table->orig_nents;

                goto err;

        }

        sg_init_table(sg, alloc_size);

        table->nents = table->orig_nents += sg_size;

        /*

         * If this is the first mapping, assign the sg table header.

         * If this is not the first mapping, chain previous part.

         */

        if (prv)

                sg_chain(prv, max_ents, sg);

        else

                table->sgl = sg;

        /*

         * If no more entries after this one, mark the end

         */

        if (!left)

                sg_mark_end(&sg[sg_size - 1]);

        prv = sg;

    } while (left);

    return 0;

err:

    __sg_free_table(table, SG_MAX_SINGLE_ALLOC, NULL);

    return -ENOMEM;

}

void sg_init_table(struct scatterlist *sgl, unsigned int nents)

{

    memset(sgl, 0, sizeof(*sgl) * nents);

#ifdef CONFIG_DEBUG_SG

    {

            unsigned int i;

            for (i = 0; i < nents; i++)

                    sgl[i].sg_magic = SG_MAGIC;

    }

#endif

    sg_mark_end(&sgl[nents - 1]);

}

void __sg_page_iter_start(struct sg_page_iter *piter,

              struct scatterlist *sglist, unsigned int nents,

              unsigned long pgoffset)

{

    piter->__pg_advance = 0;

    piter->__nents = nents;

    piter->sg = sglist;

    piter->sg_pgoffset = pgoffset;

}

static int sg_page_count(struct scatterlist *sg)

{

    return PAGE_ALIGN(sg->offset + sg->length) >> PAGE_SHIFT;

}

bool __sg_page_iter_next(struct sg_page_iter *piter)

{

    if (!piter->__nents || !piter->sg)

        return false;

    piter->sg_pgoffset += piter->__pg_advance;

    piter->__pg_advance = 1;

    while (piter->sg_pgoffset >= sg_page_count(piter->sg)) {

        piter->sg_pgoffset -= sg_page_count(piter->sg);

        piter->sg = sg_next(piter->sg);

        if (!--piter->__nents || !piter->sg)

            return false;

    }

    return true;

}

EXPORT_SYMBOL(__sg_page_iter_next);