/*
 * Copyright © 2008-2012 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>
 *    Chris Wilson <chris@chris-wilson.co.uk>
 *
 */

#include <drm/drmP.h>
#include <drm/i915_drm.h>
#include "i915_drv.h"

/*
 * The BIOS typically reserves some of the system's memory for the exclusive
 * use of the integrated graphics. This memory is no longer available for
 * use by the OS and so the user finds that his system has less memory
 * available than he put in. We refer to this memory as stolen.
 *
 * The BIOS will allocate its framebuffer from the stolen memory. Our
 * goal is try to reuse that object for our own fbcon which must always
 * be available for panics. Anything else we can reuse the stolen memory
 * for is a boon.
 */

int i915_gem_stolen_insert_node(struct drm_i915_private *dev_priv,
				struct drm_mm_node *node, u64 size,
				unsigned alignment)
{
	int ret;

	if (!drm_mm_initialized(&dev_priv->mm.stolen))
		return -ENODEV;

	mutex_lock(&dev_priv->mm.stolen_lock);
	ret = drm_mm_insert_node(&dev_priv->mm.stolen, node, size, alignment,
				 DRM_MM_SEARCH_DEFAULT);
	mutex_unlock(&dev_priv->mm.stolen_lock);

	return ret;
}

void i915_gem_stolen_remove_node(struct drm_i915_private *dev_priv,
				 struct drm_mm_node *node)
{
	mutex_lock(&dev_priv->mm.stolen_lock);
	drm_mm_remove_node(node);
	mutex_unlock(&dev_priv->mm.stolen_lock);
}

static unsigned long i915_stolen_to_physical(struct drm_device *dev)
{
	struct drm_i915_private *dev_priv = dev->dev_private;
	struct resource *r;
	u32 base;

	/* Almost universally we can find the Graphics Base of Stolen Memory
	 * at offset 0x5c in the igfx configuration space. On a few (desktop)
	 * machines this is also mirrored in the bridge device at different
	 * locations, or in the MCHBAR. On gen2, the layout is again slightly
	 * different with the Graphics Segment immediately following Top of
	 * Memory (or Top of Usable DRAM). Note it appears that TOUD is only
	 * reported by 865g, so we just use the top of memory as determined
	 * by the e820 probe.
	 *
	 * XXX However gen2 requires an unavailable symbol.
	 */
	base = 0;
	if (INTEL_INFO(dev)->gen >= 3) {
		/* Read Graphics Base of Stolen Memory directly */
		pci_read_config_dword(dev->pdev, 0x5c, &base);
		base &= ~((1<<20) - 1);
	} else { /* GEN2 */
#if 0
		/* Stolen is immediately above Top of Memory */
		base = max_low_pfn_mapped << PAGE_SHIFT;
#endif
	}

	if (base == 0)
		return 0;

	/* make sure we don't clobber the GTT if it's within stolen memory */
	if (INTEL_INFO(dev)->gen <= 4 && !IS_G33(dev) && !IS_G4X(dev)) {
		struct {
			u32 start, end;
		} stolen[2] = {
			{ .start = base, .end = base + dev_priv->gtt.stolen_size, },
			{ .start = base, .end = base + dev_priv->gtt.stolen_size, },
		};
		u64 gtt_start, gtt_end;

		gtt_start = I915_READ(PGTBL_CTL);
		if (IS_GEN4(dev))
			gtt_start = (gtt_start & PGTBL_ADDRESS_LO_MASK) |
				(gtt_start & PGTBL_ADDRESS_HI_MASK) << 28;
		else
			gtt_start &= PGTBL_ADDRESS_LO_MASK;
		gtt_end = gtt_start + gtt_total_entries(dev_priv->gtt) * 4;

		if (gtt_start >= stolen[0].start && gtt_start < stolen[0].end)
			stolen[0].end = gtt_start;
		if (gtt_end > stolen[1].start && gtt_end <= stolen[1].end)
			stolen[1].start = gtt_end;

		/* pick the larger of the two chunks */
		if (stolen[0].end - stolen[0].start >
		    stolen[1].end - stolen[1].start) {
			base = stolen[0].start;
			dev_priv->gtt.stolen_size = stolen[0].end - stolen[0].start;
		} else {
			base = stolen[1].start;
			dev_priv->gtt.stolen_size = stolen[1].end - stolen[1].start;
		}

		if (stolen[0].start != stolen[1].start ||
		    stolen[0].end != stolen[1].end) {
			DRM_DEBUG_KMS("GTT within stolen memory at 0x%llx-0x%llx\n",
				      (unsigned long long) gtt_start,
				      (unsigned long long) gtt_end - 1);
			DRM_DEBUG_KMS("Stolen memory adjusted to 0x%x-0x%x\n",
				      base, base + (u32) dev_priv->gtt.stolen_size - 1);
		}
	}


	/* Verify that nothing else uses this physical address. Stolen
	 * memory should be reserved by the BIOS and hidden from the
	 * kernel. So if the region is already marked as busy, something
	 * is seriously wrong.
	 */
	r = devm_request_mem_region(dev->dev, base, dev_priv->gtt.stolen_size,
				    "Graphics Stolen Memory");
	if (r == NULL) {
		/*
		 * One more attempt but this time requesting region from
		 * base + 1, as we have seen that this resolves the region
		 * conflict with the PCI Bus.
		 * This is a BIOS w/a: Some BIOS wrap stolen in the root
		 * PCI bus, but have an off-by-one error. Hence retry the
		 * reservation starting from 1 instead of 0.
		 */
		r = devm_request_mem_region(dev->dev, base + 1,
					    dev_priv->gtt.stolen_size - 1,
					    "Graphics Stolen Memory");
		/*
		 * GEN3 firmware likes to smash pci bridges into the stolen
		 * range. Apparently this works.
		 */
		if (r == NULL && !IS_GEN3(dev)) {
			DRM_ERROR("conflict detected with stolen region: [0x%08x - 0x%08x]\n",
				  base, base + (uint32_t)dev_priv->gtt.stolen_size);
			base = 0;
		}
	}

	return base;
}

void i915_gem_cleanup_stolen(struct drm_device *dev)
{
	struct drm_i915_private *dev_priv = dev->dev_private;

	if (!drm_mm_initialized(&dev_priv->mm.stolen))
		return;

	drm_mm_takedown(&dev_priv->mm.stolen);
}

int i915_gem_init_stolen(struct drm_device *dev)
{
	struct drm_i915_private *dev_priv = dev->dev_private;
	u32 tmp;
	int bios_reserved = 0;

	mutex_init(&dev_priv->mm.stolen_lock);

#ifdef CONFIG_INTEL_IOMMU
	if (intel_iommu_gfx_mapped && INTEL_INFO(dev)->gen < 8) {
		DRM_INFO("DMAR active, disabling use of stolen memory\n");
		return 0;
	}
#endif

	if (dev_priv->gtt.stolen_size == 0)
		return 0;

	dev_priv->mm.stolen_base = i915_stolen_to_physical(dev);
	if (dev_priv->mm.stolen_base == 0)
		return 0;

	DRM_DEBUG_KMS("found %zd bytes of stolen memory at %08lx\n",
		      dev_priv->gtt.stolen_size, dev_priv->mm.stolen_base);

	if (INTEL_INFO(dev)->gen >= 8) {
		tmp = I915_READ(GEN7_BIOS_RESERVED);
		tmp >>= GEN8_BIOS_RESERVED_SHIFT;
		tmp &= GEN8_BIOS_RESERVED_MASK;
		bios_reserved = (1024*1024) << tmp;
	} else if (IS_GEN7(dev)) {
		tmp = I915_READ(GEN7_BIOS_RESERVED);
		bios_reserved = tmp & GEN7_BIOS_RESERVED_256K ?
			256*1024 : 1024*1024;
	}

	if (WARN_ON(bios_reserved > dev_priv->gtt.stolen_size))
		return 0;

	/* Basic memrange allocator for stolen space */
	drm_mm_init(&dev_priv->mm.stolen, 0, dev_priv->gtt.stolen_size -
		    bios_reserved);

	return 0;
}

static struct sg_table *
i915_pages_create_for_stolen(struct drm_device *dev,
			     u32 offset, u32 size)
{
	struct drm_i915_private *dev_priv = dev->dev_private;
	struct sg_table *st;
	struct scatterlist *sg;

	DRM_DEBUG_DRIVER("offset=0x%x, size=%d\n", offset, size);
	BUG_ON(offset > dev_priv->gtt.stolen_size - size);

	/* We hide that we have no struct page backing our stolen object
	 * by wrapping the contiguous physical allocation with a fake
	 * dma mapping in a single scatterlist.
	 */

	st = kmalloc(sizeof(*st), GFP_KERNEL);
	if (st == NULL)
		return NULL;

	if (sg_alloc_table(st, 1, GFP_KERNEL)) {
		kfree(st);
		return NULL;
	}

	sg = st->sgl;
	sg->offset = 0;
	sg->length = size;

	sg_dma_address(sg) = (dma_addr_t)dev_priv->mm.stolen_base + offset;
	sg_dma_len(sg) = size;

	return st;
}

static int i915_gem_object_get_pages_stolen(struct drm_i915_gem_object *obj)
{
	BUG();
	return -EINVAL;
}

static void i915_gem_object_put_pages_stolen(struct drm_i915_gem_object *obj)
{
	/* Should only be called during free */
	sg_free_table(obj->pages);
	kfree(obj->pages);
}


static void
i915_gem_object_release_stolen(struct drm_i915_gem_object *obj)
{
	struct drm_i915_private *dev_priv = obj->base.dev->dev_private;

	if (obj->stolen) {
		i915_gem_stolen_remove_node(dev_priv, obj->stolen);
		kfree(obj->stolen);
		obj->stolen = NULL;
	}
}
static const struct drm_i915_gem_object_ops i915_gem_object_stolen_ops = {
	.get_pages = i915_gem_object_get_pages_stolen,
	.put_pages = i915_gem_object_put_pages_stolen,
	.release = i915_gem_object_release_stolen,
};

static struct drm_i915_gem_object *
_i915_gem_object_create_stolen(struct drm_device *dev,
			       struct drm_mm_node *stolen)
{
	struct drm_i915_gem_object *obj;

	obj = i915_gem_object_alloc(dev);
	if (obj == NULL)
		return NULL;

	drm_gem_private_object_init(dev, &obj->base, stolen->size);
	i915_gem_object_init(obj, &i915_gem_object_stolen_ops);

	obj->pages = i915_pages_create_for_stolen(dev,
						  stolen->start, stolen->size);
	if (obj->pages == NULL)
		goto cleanup;

	i915_gem_object_pin_pages(obj);
	obj->stolen = stolen;

	obj->base.read_domains = I915_GEM_DOMAIN_CPU | I915_GEM_DOMAIN_GTT;
	obj->cache_level = HAS_LLC(dev) ? I915_CACHE_LLC : I915_CACHE_NONE;

	return obj;

cleanup:
	i915_gem_object_free(obj);
	return NULL;
}

struct drm_i915_gem_object *
i915_gem_object_create_stolen(struct drm_device *dev, u32 size)
{
	struct drm_i915_private *dev_priv = dev->dev_private;
	struct drm_i915_gem_object *obj;
	struct drm_mm_node *stolen;
	int ret;

	if (!drm_mm_initialized(&dev_priv->mm.stolen))
		return NULL;

	DRM_DEBUG_KMS("creating stolen object: size=%x\n", size);
	if (size == 0)
		return NULL;

	stolen = kzalloc(sizeof(*stolen), GFP_KERNEL);
	if (!stolen)
		return NULL;

	ret = i915_gem_stolen_insert_node(dev_priv, stolen, size, 4096);
	if (ret) {
		kfree(stolen);
		return NULL;
	}

	obj = _i915_gem_object_create_stolen(dev, stolen);
	if (obj)
		return obj;

	i915_gem_stolen_remove_node(dev_priv, stolen);
	kfree(stolen);
	return NULL;
}

struct drm_i915_gem_object *
i915_gem_object_create_stolen_for_preallocated(struct drm_device *dev,
					       u32 stolen_offset,
					       u32 gtt_offset,
					       u32 size)
{
	struct drm_i915_private *dev_priv = dev->dev_private;
	struct i915_address_space *ggtt = &dev_priv->gtt.base;
	struct drm_i915_gem_object *obj;
	struct drm_mm_node *stolen;
	struct i915_vma *vma;
	int ret;

	if (!drm_mm_initialized(&dev_priv->mm.stolen))
		return NULL;

	DRM_DEBUG_KMS("creating preallocated stolen object: stolen_offset=%x, gtt_offset=%x, size=%x\n",
			stolen_offset, gtt_offset, size);

	/* KISS and expect everything to be page-aligned */
	if (WARN_ON(size == 0) || WARN_ON(size & 4095) ||
	    WARN_ON(stolen_offset & 4095))
		return NULL;

	stolen = kzalloc(sizeof(*stolen), GFP_KERNEL);
	if (!stolen)
		return NULL;

	stolen->start = stolen_offset;
	stolen->size = size;
	mutex_lock(&dev_priv->mm.stolen_lock);
	ret = drm_mm_reserve_node(&dev_priv->mm.stolen, stolen);
	mutex_unlock(&dev_priv->mm.stolen_lock);
	if (ret) {
		DRM_DEBUG_KMS("failed to allocate stolen space\n");
		kfree(stolen);
		return NULL;
	}

	obj = _i915_gem_object_create_stolen(dev, stolen);
	if (obj == NULL) {
		DRM_DEBUG_KMS("failed to allocate stolen object\n");
		i915_gem_stolen_remove_node(dev_priv, stolen);
		kfree(stolen);
		return NULL;
	}

	/* Some objects just need physical mem from stolen space */
	if (gtt_offset == I915_GTT_OFFSET_NONE)
		return obj;

	vma = i915_gem_obj_lookup_or_create_vma(obj, ggtt);
	if (IS_ERR(vma)) {
		ret = PTR_ERR(vma);
		goto err_out;
	}

	/* To simplify the initialisation sequence between KMS and GTT,
	 * we allow construction of the stolen object prior to
	 * setting up the GTT space. The actual reservation will occur
	 * later.
	 */
	vma->node.start = gtt_offset;
	vma->node.size = size;
	if (drm_mm_initialized(&ggtt->mm)) {
		ret = drm_mm_reserve_node(&ggtt->mm, &vma->node);
		if (ret) {
			DRM_DEBUG_KMS("failed to allocate stolen GTT space\n");
			goto err_vma;
		}
	}

	vma->bound |= GLOBAL_BIND;

	list_add_tail(&obj->global_list, &dev_priv->mm.bound_list);
	list_add_tail(&vma->mm_list, &ggtt->inactive_list);
	i915_gem_object_pin_pages(obj);

	return obj;

err_vma:
	i915_gem_vma_destroy(vma);
err_out:
	i915_gem_stolen_remove_node(dev_priv, stolen);
	kfree(stolen);
	drm_gem_object_unreference(&obj->base);
	return NULL;
}