/*
 * 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.
 */

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;
}

static int find_compression_threshold(struct drm_device *dev,
                                      struct drm_mm_node *node,
                                      int size,
                                      int fb_cpp)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        int compression_threshold = 1;
        int ret;

        /* HACK: This code depends on what we will do in *_enable_fbc. If that
         * code changes, this code needs to change as well.
         *
         * The enable_fbc code will attempt to use one of our 2 compression
         * thresholds, therefore, in that case, we only have 1 resort.
         */

        /* Try to over-allocate to reduce reallocations and fragmentation. */
        ret = drm_mm_insert_node(&dev_priv->mm.stolen, node,
                                 size <<= 1, 4096, DRM_MM_SEARCH_DEFAULT);
        if (ret == 0)
                return compression_threshold;

again:
        /* HW's ability to limit the CFB is 1:4 */
        if (compression_threshold > 4 ||
            (fb_cpp == 2 && compression_threshold == 2))
                return 0;

        ret = drm_mm_insert_node(&dev_priv->mm.stolen, node,
                                 size >>= 1, 4096,
                                 DRM_MM_SEARCH_DEFAULT);
        if (ret && INTEL_INFO(dev)->gen <= 4) {
                return 0;
        } else if (ret) {
                compression_threshold <<= 1;
                goto again;
        } else {
                return compression_threshold;
        }
}

static int i915_setup_compression(struct drm_device *dev, int size, int fb_cpp)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct drm_mm_node *uninitialized_var(compressed_llb);
        int ret;

        ret = find_compression_threshold(dev, &dev_priv->fbc.compressed_fb,
                                         size, fb_cpp);
        if (!ret)
                goto err_llb;
        else if (ret > 1) {
                DRM_INFO("Reducing the compressed framebuffer size. This may lead to less power savings than a non-reduced-size. Try to increase stolen memory size if available in BIOS.\n");

        }

        dev_priv->fbc.threshold = ret;

        if (HAS_PCH_SPLIT(dev))
                I915_WRITE(ILK_DPFC_CB_BASE, dev_priv->fbc.compressed_fb.start);
        else if (IS_GM45(dev)) {
                I915_WRITE(DPFC_CB_BASE, dev_priv->fbc.compressed_fb.start);
        } else {
                compressed_llb = kzalloc(sizeof(*compressed_llb), GFP_KERNEL);
                if (!compressed_llb)
                        goto err_fb;

                ret = drm_mm_insert_node(&dev_priv->mm.stolen, compressed_llb,
                                         4096, 4096, DRM_MM_SEARCH_DEFAULT);
                if (ret)
                        goto err_fb;

                dev_priv->fbc.compressed_llb = compressed_llb;

                I915_WRITE(FBC_CFB_BASE,
                           dev_priv->mm.stolen_base + dev_priv->fbc.compressed_fb.start);
                I915_WRITE(FBC_LL_BASE,
                           dev_priv->mm.stolen_base + compressed_llb->start);
        }

        dev_priv->fbc.size = size / dev_priv->fbc.threshold;

        DRM_DEBUG_KMS("reserved %d bytes of contiguous stolen space for FBC\n",
                      size);

        return 0;

err_fb:
        kfree(compressed_llb);
        drm_mm_remove_node(&dev_priv->fbc.compressed_fb);
err_llb:
        pr_info_once("drm: not enough stolen space for compressed buffer (need %d more bytes), disabling. Hint: you may be able to increase stolen memory size in the BIOS to avoid this.\n", size);
        return -ENOSPC;
}

int i915_gem_stolen_setup_compression(struct drm_device *dev, int size, int fb_cpp)
{
        struct drm_i915_private *dev_priv = dev->dev_private;

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

        if (size < dev_priv->fbc.size)
                return 0;

        /* Release any current block */
        i915_gem_stolen_cleanup_compression(dev);

        return i915_setup_compression(dev, size, fb_cpp);
}

void i915_gem_stolen_cleanup_compression(struct drm_device *dev)
{
        struct drm_i915_private *dev_priv = dev->dev_private;

        if (dev_priv->fbc.size == 0)
                return;

        drm_mm_remove_node(&dev_priv->fbc.compressed_fb);

        if (dev_priv->fbc.compressed_llb) {
                drm_mm_remove_node(dev_priv->fbc.compressed_llb);
                kfree(dev_priv->fbc.compressed_llb);
        }

        dev_priv->fbc.size = 0;
}

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;

        i915_gem_stolen_cleanup_compression(dev);
        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;

#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)
{
        if (obj->stolen) {
                drm_mm_remove_node(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;

        obj->has_dma_mapping = true;
        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 = drm_mm_insert_node(&dev_priv->mm.stolen, stolen, size,
                                 4096, DRM_MM_SEARCH_DEFAULT);
        if (ret) {
                kfree(stolen);
                return NULL;
        }

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

        drm_mm_remove_node(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;
        ret = drm_mm_reserve_node(&dev_priv->mm.stolen, stolen);
        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");
                drm_mm_remove_node(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:
        drm_mm_remove_node(stolen);
        kfree(stolen);
        drm_gem_object_unreference(&obj->base);
        return NULL;
}