drivers/gpu/drm/i915/i915_gem_gtt.c - kernel/msm-4.19 - Gitiles

 /*
  * 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.
  *
  */

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

 /* PPGTT support for Sandybdrige/Gen6 and later */
 static void i915_ppgtt_clear_range(struct i915_hw_ppgtt *ppgtt,
 				   unsigned first_entry,
 				   unsigned num_entries)
 {
 	uint32_t *pt_vaddr;
 	uint32_t scratch_pte;
 	unsigned act_pd = first_entry / I915_PPGTT_PT_ENTRIES;
 	unsigned first_pte = first_entry % I915_PPGTT_PT_ENTRIES;
 	unsigned last_pte, i;

 	scratch_pte = GEN6_PTE_ADDR_ENCODE(ppgtt->scratch_page_dma_addr);
 	scratch_pte |= GEN6_PTE_VALID | GEN6_PTE_CACHE_LLC;

 	while (num_entries) {
 		last_pte = first_pte + num_entries;
 		if (last_pte > I915_PPGTT_PT_ENTRIES)
 			last_pte = I915_PPGTT_PT_ENTRIES;

 		pt_vaddr = kmap_atomic(ppgtt->pt_pages[act_pd]);

 		for (i = first_pte; i < last_pte; i++)
 			pt_vaddr[i] = scratch_pte;

 		kunmap_atomic(pt_vaddr);

 		num_entries -= last_pte - first_pte;
 		first_pte = 0;
 		act_pd++;
 	}
 }

 int i915_gem_init_aliasing_ppgtt(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct i915_hw_ppgtt *ppgtt;
 	uint32_t pd_entry;
 	unsigned first_pd_entry_in_global_pt;
 	uint32_t __iomem *pd_addr;
 	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 = 512*1024 - I915_PPGTT_PD_ENTRIES;

 	ppgtt = kzalloc(sizeof(*ppgtt), GFP_KERNEL);
 	if (!ppgtt)
 		return ret;

 	ppgtt->num_pd_entries = I915_PPGTT_PD_ENTRIES;
 	ppgtt->pt_pages = kzalloc(sizeof(struct page *)*ppgtt->num_pd_entries,
 				  GFP_KERNEL);
 	if (!ppgtt->pt_pages)
 		goto err_ppgtt;

 	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;
 	}

 	if (dev_priv->mm.gtt->needs_dmar) {
 		ppgtt->pt_dma_addr = kzalloc(sizeof(dma_addr_t)
 						*ppgtt->num_pd_entries,
 					     GFP_KERNEL);
 		if (!ppgtt->pt_dma_addr)
 			goto err_pt_alloc;
 	}

 	pd_addr = dev_priv->mm.gtt->gtt + first_pd_entry_in_global_pt;
 	for (i = 0; i < ppgtt->num_pd_entries; i++) {
 		dma_addr_t pt_addr;
 		if (dev_priv->mm.gtt->needs_dmar) {
 			pt_addr = pci_map_page(dev->pdev, ppgtt->pt_pages[i],
 					       0, 4096,
 					       PCI_DMA_BIDIRECTIONAL);

 			if (pci_dma_mapping_error(dev->pdev,
 						  pt_addr)) {
 				ret = -EIO;
 				goto err_pd_pin;

 			}
 			ppgtt->pt_dma_addr[i] = pt_addr;
 		} else
 			pt_addr = page_to_phys(ppgtt->pt_pages[i]);

 		pd_entry = GEN6_PDE_ADDR_ENCODE(pt_addr);
 		pd_entry |= GEN6_PDE_VALID;

 		writel(pd_entry, pd_addr + i);
 	}
 	readl(pd_addr);

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

 	i915_ppgtt_clear_range(ppgtt, 0,
 			       ppgtt->num_pd_entries*I915_PPGTT_PT_ENTRIES);

 	ppgtt->pd_offset = (first_pd_entry_in_global_pt)*sizeof(uint32_t);

 	dev_priv->mm.aliasing_ppgtt = ppgtt;

 	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);
 err_ppgtt:
 	kfree(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;
 	int i;

 	if (!ppgtt)
 		return;

 	if (ppgtt->pt_dma_addr) {
 		for (i = 0; i < ppgtt->num_pd_entries; i++)
 			pci_unmap_page(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 void i915_ppgtt_insert_sg_entries(struct i915_hw_ppgtt *ppgtt,
 					 struct scatterlist *sg_list,
 					 unsigned sg_len,
 					 unsigned first_entry,
 					 uint32_t pte_flags)
 {
 	uint32_t *pt_vaddr, pte;
 	unsigned act_pd = first_entry / I915_PPGTT_PT_ENTRIES;
 	unsigned first_pte = first_entry % I915_PPGTT_PT_ENTRIES;
 	unsigned i, j, m, segment_len;
 	dma_addr_t page_addr;
 	struct scatterlist *sg;

 	/* init sg walking */
 	sg = sg_list;
 	i = 0;
 	segment_len = sg_dma_len(sg) >> PAGE_SHIFT;
 	m = 0;

 	while (i < sg_len) {
 		pt_vaddr = kmap_atomic(ppgtt->pt_pages[act_pd]);

 		for (j = first_pte; j < I915_PPGTT_PT_ENTRIES; j++) {
 			page_addr = sg_dma_address(sg) + (m << PAGE_SHIFT);
 			pte = GEN6_PTE_ADDR_ENCODE(page_addr);
 			pt_vaddr[j] = pte | pte_flags;

 			/* grab the next page */
 			m++;
 			if (m == segment_len) {
 				sg = sg_next(sg);
 				i++;
 				if (i == sg_len)
 					break;

 				segment_len = sg_dma_len(sg) >> PAGE_SHIFT;
 				m = 0;
 			}
 		}

 		kunmap_atomic(pt_vaddr);

 		first_pte = 0;
 		act_pd++;
 	}
 }

 static void i915_ppgtt_insert_pages(struct i915_hw_ppgtt *ppgtt,
 				    unsigned first_entry, unsigned num_entries,
 				    struct page **pages, uint32_t pte_flags)
 {
 	uint32_t *pt_vaddr, pte;
 	unsigned act_pd = first_entry / I915_PPGTT_PT_ENTRIES;
 	unsigned first_pte = first_entry % I915_PPGTT_PT_ENTRIES;
 	unsigned last_pte, i;
 	dma_addr_t page_addr;

 	while (num_entries) {
 		last_pte = first_pte + num_entries;
 		last_pte = min_t(unsigned, last_pte, I915_PPGTT_PT_ENTRIES);

 		pt_vaddr = kmap_atomic(ppgtt->pt_pages[act_pd]);

 		for (i = first_pte; i < last_pte; i++) {
 			page_addr = page_to_phys(*pages);
 			pte = GEN6_PTE_ADDR_ENCODE(page_addr);
 			pt_vaddr[i] = pte | pte_flags;

 			pages++;
 		}

 		kunmap_atomic(pt_vaddr);

 		num_entries -= last_pte - first_pte;
 		first_pte = 0;
 		act_pd++;
 	}
 }

 void i915_ppgtt_bind_object(struct i915_hw_ppgtt *ppgtt,
 			    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;
 	uint32_t pte_flags = GEN6_PTE_VALID;

 	switch (cache_level) {
 	case I915_CACHE_LLC_MLC:
 		pte_flags |= GEN6_PTE_CACHE_LLC_MLC;
 		break;
 	case I915_CACHE_LLC:
 		pte_flags |= GEN6_PTE_CACHE_LLC;
 		break;
 	case I915_CACHE_NONE:
 		pte_flags |= GEN6_PTE_UNCACHED;
 		break;
 	default:
 		BUG();
 	}

 	if (dev_priv->mm.gtt->needs_dmar) {
 		BUG_ON(!obj->sg_list);

 		i915_ppgtt_insert_sg_entries(ppgtt,
 					     obj->sg_list,
 					     obj->num_sg,
 					     obj->gtt_space->start >> PAGE_SHIFT,
 					     pte_flags);
 	} else
 		i915_ppgtt_insert_pages(ppgtt,
 					obj->gtt_space->start >> PAGE_SHIFT,
 					obj->base.size >> PAGE_SHIFT,
 					obj->pages,
 					pte_flags);
 }

 void i915_ppgtt_unbind_object(struct i915_hw_ppgtt *ppgtt,
 			      struct drm_i915_gem_object *obj)
 {
 	i915_ppgtt_clear_range(ppgtt,
 			       obj->gtt_space->start >> PAGE_SHIFT,
 			       obj->base.size >> PAGE_SHIFT);
 }

 /* XXX kill agp_type! */
 static unsigned int cache_level_to_agp_type(struct drm_device *dev,
 					    enum i915_cache_level cache_level)
 {
 	switch (cache_level) {
 	case I915_CACHE_LLC_MLC:
 		if (INTEL_INFO(dev)->gen >= 6)
 			return AGP_USER_CACHED_MEMORY_LLC_MLC;
 		/* Older chipsets do not have this extra level of CPU
 		 * cacheing, so fallthrough and request the PTE simply
 		 * as cached.
 		 */
 	case I915_CACHE_LLC:
 		return AGP_USER_CACHED_MEMORY;
 	default:
 	case I915_CACHE_NONE:
 		return AGP_USER_MEMORY;
 	}
 }

 static bool do_idling(struct drm_i915_private *dev_priv)
 {
 	bool ret = dev_priv->mm.interruptible;

 	if (unlikely(dev_priv->mm.gtt->do_idle_maps)) {
 		dev_priv->mm.interruptible = false;
 		if (i915_gpu_idle(dev_priv->dev, false)) {
 			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->mm.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 */
 	intel_gtt_clear_range(dev_priv->mm.gtt_start / PAGE_SIZE,
 			      (dev_priv->mm.gtt_end - dev_priv->mm.gtt_start) / PAGE_SIZE);

 	list_for_each_entry(obj, &dev_priv->mm.gtt_list, gtt_list) {
 		i915_gem_clflush_object(obj);
 		i915_gem_gtt_bind_object(obj, obj->cache_level);
 	}

 	intel_gtt_chipset_flush();
 }

 int i915_gem_gtt_prepare_object(struct drm_i915_gem_object *obj)
 {
 	struct drm_device *dev = obj->base.dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;

 	if (dev_priv->mm.gtt->needs_dmar)
 		return intel_gtt_map_memory(obj->pages,
 					    obj->base.size >> PAGE_SHIFT,
 					    &obj->sg_list,
 					    &obj->num_sg);
 	else
 		return 0;
 }

 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;
 	unsigned int agp_type = cache_level_to_agp_type(dev, cache_level);

 	if (dev_priv->mm.gtt->needs_dmar) {
 		BUG_ON(!obj->sg_list);

 		intel_gtt_insert_sg_entries(obj->sg_list,
 					    obj->num_sg,
 					    obj->gtt_space->start >> PAGE_SHIFT,
 					    agp_type);
 	} else
 		intel_gtt_insert_pages(obj->gtt_space->start >> PAGE_SHIFT,
 				       obj->base.size >> PAGE_SHIFT,
 				       obj->pages,
 				       agp_type);

 	obj->has_global_gtt_mapping = 1;
 }

 void i915_gem_gtt_unbind_object(struct drm_i915_gem_object *obj)
 {
 	intel_gtt_clear_range(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->sg_list) {
 		intel_gtt_unmap_memory(obj->sg_list, obj->num_sg);
 		obj->sg_list = NULL;
 	}

 	undo_idling(dev_priv, interruptible);
 }

 void i915_gem_init_global_gtt(struct drm_device *dev,
 			      unsigned long start,
 			      unsigned long mappable_end,
 			      unsigned long end)
 {
 	drm_i915_private_t *dev_priv = dev->dev_private;

 	/* Substract the guard page ... */
 	drm_mm_init(&dev_priv->mm.gtt_space, start, end - start - PAGE_SIZE);

 	dev_priv->mm.gtt_start = start;
 	dev_priv->mm.gtt_mappable_end = mappable_end;
 	dev_priv->mm.gtt_end = end;
 	dev_priv->mm.gtt_total = end - start;
 	dev_priv->mm.mappable_gtt_total = min(end, mappable_end) - start;

 	/* ... but ensure that we clear the entire range. */
 	intel_gtt_clear_range(start / PAGE_SIZE, (end-start) / PAGE_SIZE);
 }
	/*
	* 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.
	*
	*/

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

	/* PPGTT support for Sandybdrige/Gen6 and later */
	static void i915_ppgtt_clear_range(struct i915_hw_ppgtt *ppgtt,
	unsigned first_entry,
	unsigned num_entries)
	{
	uint32_t *pt_vaddr;
	uint32_t scratch_pte;
	unsigned act_pd = first_entry / I915_PPGTT_PT_ENTRIES;
	unsigned first_pte = first_entry % I915_PPGTT_PT_ENTRIES;
	unsigned last_pte, i;

	scratch_pte = GEN6_PTE_ADDR_ENCODE(ppgtt->scratch_page_dma_addr);
	scratch_pte \|= GEN6_PTE_VALID \| GEN6_PTE_CACHE_LLC;

	while (num_entries) {
	last_pte = first_pte + num_entries;
	if (last_pte > I915_PPGTT_PT_ENTRIES)
	last_pte = I915_PPGTT_PT_ENTRIES;

	pt_vaddr = kmap_atomic(ppgtt->pt_pages[act_pd]);

	for (i = first_pte; i < last_pte; i++)
	pt_vaddr[i] = scratch_pte;

	kunmap_atomic(pt_vaddr);

	num_entries -= last_pte - first_pte;
	first_pte = 0;
	act_pd++;
	}
	}

	int i915_gem_init_aliasing_ppgtt(struct drm_device *dev)
	{
	struct drm_i915_private *dev_priv = dev->dev_private;
	struct i915_hw_ppgtt *ppgtt;
	uint32_t pd_entry;
	unsigned first_pd_entry_in_global_pt;
	uint32_t __iomem *pd_addr;
	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 = 512*1024 - I915_PPGTT_PD_ENTRIES;

	ppgtt = kzalloc(sizeof(*ppgtt), GFP_KERNEL);
	if (!ppgtt)
	return ret;

	ppgtt->num_pd_entries = I915_PPGTT_PD_ENTRIES;
	ppgtt->pt_pages = kzalloc(sizeof(struct page )ppgtt->num_pd_entries,
	GFP_KERNEL);
	if (!ppgtt->pt_pages)
	goto err_ppgtt;

	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;
	}

	if (dev_priv->mm.gtt->needs_dmar) {
	ppgtt->pt_dma_addr = kzalloc(sizeof(dma_addr_t)
	*ppgtt->num_pd_entries,
	GFP_KERNEL);
	if (!ppgtt->pt_dma_addr)
	goto err_pt_alloc;
	}

	pd_addr = dev_priv->mm.gtt->gtt + first_pd_entry_in_global_pt;
	for (i = 0; i < ppgtt->num_pd_entries; i++) {
	dma_addr_t pt_addr;
	if (dev_priv->mm.gtt->needs_dmar) {
	pt_addr = pci_map_page(dev->pdev, ppgtt->pt_pages[i],
	0, 4096,
	PCI_DMA_BIDIRECTIONAL);

	if (pci_dma_mapping_error(dev->pdev,
	pt_addr)) {
	ret = -EIO;
	goto err_pd_pin;

	}
	ppgtt->pt_dma_addr[i] = pt_addr;
	} else
	pt_addr = page_to_phys(ppgtt->pt_pages[i]);

	pd_entry = GEN6_PDE_ADDR_ENCODE(pt_addr);
	pd_entry \|= GEN6_PDE_VALID;

	writel(pd_entry, pd_addr + i);
	}
	readl(pd_addr);

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

	i915_ppgtt_clear_range(ppgtt, 0,
	ppgtt->num_pd_entries*I915_PPGTT_PT_ENTRIES);

	ppgtt->pd_offset = (first_pd_entry_in_global_pt)*sizeof(uint32_t);

	dev_priv->mm.aliasing_ppgtt = ppgtt;

	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);
	err_ppgtt:
	kfree(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;
	int i;

	if (!ppgtt)
	return;

	if (ppgtt->pt_dma_addr) {
	for (i = 0; i < ppgtt->num_pd_entries; i++)
	pci_unmap_page(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 void i915_ppgtt_insert_sg_entries(struct i915_hw_ppgtt *ppgtt,
	struct scatterlist *sg_list,
	unsigned sg_len,
	unsigned first_entry,
	uint32_t pte_flags)
	{
	uint32_t *pt_vaddr, pte;
	unsigned act_pd = first_entry / I915_PPGTT_PT_ENTRIES;
	unsigned first_pte = first_entry % I915_PPGTT_PT_ENTRIES;
	unsigned i, j, m, segment_len;
	dma_addr_t page_addr;
	struct scatterlist *sg;

	/* init sg walking */
	sg = sg_list;
	i = 0;
	segment_len = sg_dma_len(sg) >> PAGE_SHIFT;
	m = 0;

	while (i < sg_len) {
	pt_vaddr = kmap_atomic(ppgtt->pt_pages[act_pd]);

	for (j = first_pte; j < I915_PPGTT_PT_ENTRIES; j++) {
	page_addr = sg_dma_address(sg) + (m << PAGE_SHIFT);
	pte = GEN6_PTE_ADDR_ENCODE(page_addr);
	pt_vaddr[j] = pte \| pte_flags;

	/* grab the next page */
	m++;
	if (m == segment_len) {
	sg = sg_next(sg);
	i++;
	if (i == sg_len)
	break;

	segment_len = sg_dma_len(sg) >> PAGE_SHIFT;
	m = 0;
	}
	}

	kunmap_atomic(pt_vaddr);

	first_pte = 0;
	act_pd++;
	}
	}

	static void i915_ppgtt_insert_pages(struct i915_hw_ppgtt *ppgtt,
	unsigned first_entry, unsigned num_entries,
	struct page **pages, uint32_t pte_flags)
	{
	uint32_t *pt_vaddr, pte;
	unsigned act_pd = first_entry / I915_PPGTT_PT_ENTRIES;
	unsigned first_pte = first_entry % I915_PPGTT_PT_ENTRIES;
	unsigned last_pte, i;
	dma_addr_t page_addr;

	while (num_entries) {
	last_pte = first_pte + num_entries;
	last_pte = min_t(unsigned, last_pte, I915_PPGTT_PT_ENTRIES);

	pt_vaddr = kmap_atomic(ppgtt->pt_pages[act_pd]);

	for (i = first_pte; i < last_pte; i++) {
	page_addr = page_to_phys(*pages);
	pte = GEN6_PTE_ADDR_ENCODE(page_addr);
	pt_vaddr[i] = pte \| pte_flags;

	pages++;
	}

	kunmap_atomic(pt_vaddr);

	num_entries -= last_pte - first_pte;
	first_pte = 0;
	act_pd++;
	}
	}

	void i915_ppgtt_bind_object(struct i915_hw_ppgtt *ppgtt,
	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;
	uint32_t pte_flags = GEN6_PTE_VALID;

	switch (cache_level) {
	case I915_CACHE_LLC_MLC:
	pte_flags \|= GEN6_PTE_CACHE_LLC_MLC;
	break;
	case I915_CACHE_LLC:
	pte_flags \|= GEN6_PTE_CACHE_LLC;
	break;
	case I915_CACHE_NONE:
	pte_flags \|= GEN6_PTE_UNCACHED;
	break;
	default:
	BUG();
	}

	if (dev_priv->mm.gtt->needs_dmar) {
	BUG_ON(!obj->sg_list);

	i915_ppgtt_insert_sg_entries(ppgtt,
	obj->sg_list,
	obj->num_sg,
	obj->gtt_space->start >> PAGE_SHIFT,
	pte_flags);
	} else
	i915_ppgtt_insert_pages(ppgtt,
	obj->gtt_space->start >> PAGE_SHIFT,
	obj->base.size >> PAGE_SHIFT,
	obj->pages,
	pte_flags);
	}

	void i915_ppgtt_unbind_object(struct i915_hw_ppgtt *ppgtt,
	struct drm_i915_gem_object *obj)
	{
	i915_ppgtt_clear_range(ppgtt,
	obj->gtt_space->start >> PAGE_SHIFT,
	obj->base.size >> PAGE_SHIFT);
	}

	/* XXX kill agp_type! */
	static unsigned int cache_level_to_agp_type(struct drm_device *dev,
	enum i915_cache_level cache_level)
	{
	switch (cache_level) {
	case I915_CACHE_LLC_MLC:
	if (INTEL_INFO(dev)->gen >= 6)
	return AGP_USER_CACHED_MEMORY_LLC_MLC;
	/* Older chipsets do not have this extra level of CPU
	* cacheing, so fallthrough and request the PTE simply
	* as cached.
	*/
	case I915_CACHE_LLC:
	return AGP_USER_CACHED_MEMORY;
	default:
	case I915_CACHE_NONE:
	return AGP_USER_MEMORY;
	}
	}

	static bool do_idling(struct drm_i915_private *dev_priv)
	{
	bool ret = dev_priv->mm.interruptible;

	if (unlikely(dev_priv->mm.gtt->do_idle_maps)) {
	dev_priv->mm.interruptible = false;
	if (i915_gpu_idle(dev_priv->dev, false)) {
	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->mm.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 */
	intel_gtt_clear_range(dev_priv->mm.gtt_start / PAGE_SIZE,
	(dev_priv->mm.gtt_end - dev_priv->mm.gtt_start) / PAGE_SIZE);

	list_for_each_entry(obj, &dev_priv->mm.gtt_list, gtt_list) {
	i915_gem_clflush_object(obj);
	i915_gem_gtt_bind_object(obj, obj->cache_level);
	}

	intel_gtt_chipset_flush();
	}

	int i915_gem_gtt_prepare_object(struct drm_i915_gem_object *obj)
	{
	struct drm_device *dev = obj->base.dev;
	struct drm_i915_private *dev_priv = dev->dev_private;

	if (dev_priv->mm.gtt->needs_dmar)
	return intel_gtt_map_memory(obj->pages,
	obj->base.size >> PAGE_SHIFT,
	&obj->sg_list,
	&obj->num_sg);
	else
	return 0;
	}

	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;
	unsigned int agp_type = cache_level_to_agp_type(dev, cache_level);

	if (dev_priv->mm.gtt->needs_dmar) {
	BUG_ON(!obj->sg_list);

	intel_gtt_insert_sg_entries(obj->sg_list,
	obj->num_sg,
	obj->gtt_space->start >> PAGE_SHIFT,
	agp_type);
	} else
	intel_gtt_insert_pages(obj->gtt_space->start >> PAGE_SHIFT,
	obj->base.size >> PAGE_SHIFT,
	obj->pages,
	agp_type);

	obj->has_global_gtt_mapping = 1;
	}

	void i915_gem_gtt_unbind_object(struct drm_i915_gem_object *obj)
	{
	intel_gtt_clear_range(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->sg_list) {
	intel_gtt_unmap_memory(obj->sg_list, obj->num_sg);
	obj->sg_list = NULL;
	}

	undo_idling(dev_priv, interruptible);
	}

	void i915_gem_init_global_gtt(struct drm_device *dev,
	unsigned long start,
	unsigned long mappable_end,
	unsigned long end)
	{
	drm_i915_private_t *dev_priv = dev->dev_private;

	/* Substract the guard page ... */
	drm_mm_init(&dev_priv->mm.gtt_space, start, end - start - PAGE_SIZE);

	dev_priv->mm.gtt_start = start;
	dev_priv->mm.gtt_mappable_end = mappable_end;
	dev_priv->mm.gtt_end = end;
	dev_priv->mm.gtt_total = end - start;
	dev_priv->mm.mappable_gtt_total = min(end, mappable_end) - start;

	/* ... but ensure that we clear the entire range. */
	intel_gtt_clear_range(start / PAGE_SIZE, (end-start) / PAGE_SIZE);
	}