/*
 * SPDX-License-Identifier: MIT
 *
 * Copyright © 2008-2012 Intel Corporation
 */

#include <linux/errno.h>
#include <linux/mutex.h>

#include <drm/drm_mm.h>
#include <drm/i915_drm.h>

#include "gem/i915_gem_lmem.h"
#include "gem/i915_gem_region.h"
#include "i915_drv.h"
#include "i915_gem_stolen.h"
#include "i915_vgpu.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_in_range(struct drm_i915_private *i915,
                                         struct drm_mm_node *node, u64 size,
                                         unsigned alignment, u64 start, u64 end)
{
        int ret;

        if (!drm_mm_initialized(&i915->mm.stolen))
                return -ENODEV;

        /* WaSkipStolenMemoryFirstPage:bdw+ */
        if (GRAPHICS_VER(i915) >= 8 && start < 4096)
                start = 4096;

        mutex_lock(&i915->mm.stolen_lock);
        ret = drm_mm_insert_node_in_range(&i915->mm.stolen, node,
                                          size, alignment, 0,
                                          start, end, DRM_MM_INSERT_BEST);
        mutex_unlock(&i915->mm.stolen_lock);

        return ret;
}

int i915_gem_stolen_insert_node(struct drm_i915_private *i915,
                                struct drm_mm_node *node, u64 size,
                                unsigned alignment)
{
        return i915_gem_stolen_insert_node_in_range(i915, node,
                                                    size, alignment,
                                                    I915_GEM_STOLEN_BIAS,
                                                    U64_MAX);
}

void i915_gem_stolen_remove_node(struct drm_i915_private *i915,
                                 struct drm_mm_node *node)
{
        mutex_lock(&i915->mm.stolen_lock);
        drm_mm_remove_node(node);
        mutex_unlock(&i915->mm.stolen_lock);
}

static int i915_adjust_stolen(struct drm_i915_private *i915,
                              struct resource *dsm)
{
        struct i915_ggtt *ggtt = &i915->ggtt;
        struct intel_uncore *uncore = ggtt->vm.gt->uncore;
        struct resource *r;

        if (dsm->start == 0 || dsm->end <= dsm->start)
                return -EINVAL;

        /*
         * TODO: We have yet too encounter the case where the GTT wasn't at the
         * end of stolen. With that assumption we could simplify this.
         */

        /* Make sure we don't clobber the GTT if it's within stolen memory */
        if (GRAPHICS_VER(i915) <= 4 &&
            !IS_G33(i915) && !IS_PINEVIEW(i915) && !IS_G4X(i915)) {
                struct resource stolen[2] = {*dsm, *dsm};
                struct resource ggtt_res;
                resource_size_t ggtt_start;

                ggtt_start = intel_uncore_read(uncore, PGTBL_CTL);
                if (GRAPHICS_VER(i915) == 4)
                        ggtt_start = (ggtt_start & PGTBL_ADDRESS_LO_MASK) |
                                     (ggtt_start & PGTBL_ADDRESS_HI_MASK) << 28;
                else
                        ggtt_start &= PGTBL_ADDRESS_LO_MASK;

                ggtt_res =
                        (struct resource) DEFINE_RES_MEM(ggtt_start,
                                                         ggtt_total_entries(ggtt) * 4);

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

                /* Pick the larger of the two chunks */
                if (resource_size(&stolen[0]) > resource_size(&stolen[1]))
                        *dsm = stolen[0];
                else
                        *dsm = stolen[1];

                if (stolen[0].start != stolen[1].start ||
                    stolen[0].end != stolen[1].end) {
                        drm_dbg(&i915->drm,
                                "GTT within stolen memory at %pR\n",
                                &ggtt_res);
                        drm_dbg(&i915->drm, "Stolen memory adjusted to %pR\n",
                                dsm);
                }
        }

        /*
         * With stolen lmem, we don't need to check if the address range
         * overlaps with the non-stolen system memory range, since lmem is local
         * to the gpu.
         */
        if (HAS_LMEM(i915))
                return 0;

        /*
         * 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(i915->drm.dev, dsm->start,
                                    resource_size(dsm),
                                    "Graphics Stolen Memory");
        if (r == NULL) {
                /*
                 * One more attempt but this time requesting region from
                 * start + 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.
                 * There's also BIOS with off-by-one on the other end.
                 */
                r = devm_request_mem_region(i915->drm.dev, dsm->start + 1,
                                            resource_size(dsm) - 2,
                                            "Graphics Stolen Memory");
                /*
                 * GEN3 firmware likes to smash pci bridges into the stolen
                 * range. Apparently this works.
                 */
                if (!r && GRAPHICS_VER(i915) != 3) {
                        drm_err(&i915->drm,
                                "conflict detected with stolen region: %pR\n",
                                dsm);

                        return -EBUSY;
                }
        }

        return 0;
}

static void i915_gem_cleanup_stolen(struct drm_i915_private *i915)
{
        if (!drm_mm_initialized(&i915->mm.stolen))
                return;

        drm_mm_takedown(&i915->mm.stolen);
}

static void g4x_get_stolen_reserved(struct drm_i915_private *i915,
                                    struct intel_uncore *uncore,
                                    resource_size_t *base,
                                    resource_size_t *size)
{
        u32 reg_val = intel_uncore_read(uncore,
                                        IS_GM45(i915) ?
                                        CTG_STOLEN_RESERVED :
                                        ELK_STOLEN_RESERVED);
        resource_size_t stolen_top = i915->dsm.end + 1;

        drm_dbg(&i915->drm, "%s_STOLEN_RESERVED = %08x\n",
                IS_GM45(i915) ? "CTG" : "ELK", reg_val);

        if ((reg_val & G4X_STOLEN_RESERVED_ENABLE) == 0)
                return;

        /*
         * Whether ILK really reuses the ELK register for this is unclear.
         * Let's see if we catch anyone with this supposedly enabled on ILK.
         */
        drm_WARN(&i915->drm, GRAPHICS_VER(i915) == 5,
                 "ILK stolen reserved found? 0x%08x\n",
                 reg_val);

        if (!(reg_val & G4X_STOLEN_RESERVED_ADDR2_MASK))
                return;

        *base = (reg_val & G4X_STOLEN_RESERVED_ADDR2_MASK) << 16;
        drm_WARN_ON(&i915->drm,
                    (reg_val & G4X_STOLEN_RESERVED_ADDR1_MASK) < *base);

        *size = stolen_top - *base;
}

static void gen6_get_stolen_reserved(struct drm_i915_private *i915,
                                     struct intel_uncore *uncore,
                                     resource_size_t *base,
                                     resource_size_t *size)
{
        u32 reg_val = intel_uncore_read(uncore, GEN6_STOLEN_RESERVED);

        drm_dbg(&i915->drm, "GEN6_STOLEN_RESERVED = %08x\n", reg_val);

        if (!(reg_val & GEN6_STOLEN_RESERVED_ENABLE))
                return;

        *base = reg_val & GEN6_STOLEN_RESERVED_ADDR_MASK;

        switch (reg_val & GEN6_STOLEN_RESERVED_SIZE_MASK) {
        case GEN6_STOLEN_RESERVED_1M:
                *size = 1024 * 1024;
                break;
        case GEN6_STOLEN_RESERVED_512K:
                *size = 512 * 1024;
                break;
        case GEN6_STOLEN_RESERVED_256K:
                *size = 256 * 1024;
                break;
        case GEN6_STOLEN_RESERVED_128K:
                *size = 128 * 1024;
                break;
        default:
                *size = 1024 * 1024;
                MISSING_CASE(reg_val & GEN6_STOLEN_RESERVED_SIZE_MASK);
        }
}

static void vlv_get_stolen_reserved(struct drm_i915_private *i915,
                                    struct intel_uncore *uncore,
                                    resource_size_t *base,
                                    resource_size_t *size)
{
        u32 reg_val = intel_uncore_read(uncore, GEN6_STOLEN_RESERVED);
        resource_size_t stolen_top = i915->dsm.end + 1;

        drm_dbg(&i915->drm, "GEN6_STOLEN_RESERVED = %08x\n", reg_val);

        if (!(reg_val & GEN6_STOLEN_RESERVED_ENABLE))
                return;

        switch (reg_val & GEN7_STOLEN_RESERVED_SIZE_MASK) {
        default:
                MISSING_CASE(reg_val & GEN7_STOLEN_RESERVED_SIZE_MASK);
                fallthrough;
        case GEN7_STOLEN_RESERVED_1M:
                *size = 1024 * 1024;
                break;
        }

        /*
         * On vlv, the ADDR_MASK portion is left as 0 and HW deduces the
         * reserved location as (top - size).
         */
        *base = stolen_top - *size;
}

static void gen7_get_stolen_reserved(struct drm_i915_private *i915,
                                     struct intel_uncore *uncore,
                                     resource_size_t *base,
                                     resource_size_t *size)
{
        u32 reg_val = intel_uncore_read(uncore, GEN6_STOLEN_RESERVED);

        drm_dbg(&i915->drm, "GEN6_STOLEN_RESERVED = %08x\n", reg_val);

        if (!(reg_val & GEN6_STOLEN_RESERVED_ENABLE))
                return;

        *base = reg_val & GEN7_STOLEN_RESERVED_ADDR_MASK;

        switch (reg_val & GEN7_STOLEN_RESERVED_SIZE_MASK) {
        case GEN7_STOLEN_RESERVED_1M:
                *size = 1024 * 1024;
                break;
        case GEN7_STOLEN_RESERVED_256K:
                *size = 256 * 1024;
                break;
        default:
                *size = 1024 * 1024;
                MISSING_CASE(reg_val & GEN7_STOLEN_RESERVED_SIZE_MASK);
        }
}

static void chv_get_stolen_reserved(struct drm_i915_private *i915,
                                    struct intel_uncore *uncore,
                                    resource_size_t *base,
                                    resource_size_t *size)
{
        u32 reg_val = intel_uncore_read(uncore, GEN6_STOLEN_RESERVED);

        drm_dbg(&i915->drm, "GEN6_STOLEN_RESERVED = %08x\n", reg_val);

        if (!(reg_val & GEN6_STOLEN_RESERVED_ENABLE))
                return;

        *base = reg_val & GEN6_STOLEN_RESERVED_ADDR_MASK;

        switch (reg_val & GEN8_STOLEN_RESERVED_SIZE_MASK) {
        case GEN8_STOLEN_RESERVED_1M:
                *size = 1024 * 1024;
                break;
        case GEN8_STOLEN_RESERVED_2M:
                *size = 2 * 1024 * 1024;
                break;
        case GEN8_STOLEN_RESERVED_4M:
                *size = 4 * 1024 * 1024;
                break;
        case GEN8_STOLEN_RESERVED_8M:
                *size = 8 * 1024 * 1024;
                break;
        default:
                *size = 8 * 1024 * 1024;
                MISSING_CASE(reg_val & GEN8_STOLEN_RESERVED_SIZE_MASK);
        }
}

static void bdw_get_stolen_reserved(struct drm_i915_private *i915,
                                    struct intel_uncore *uncore,
                                    resource_size_t *base,
                                    resource_size_t *size)
{
        u32 reg_val = intel_uncore_read(uncore, GEN6_STOLEN_RESERVED);
        resource_size_t stolen_top = i915->dsm.end + 1;

        drm_dbg(&i915->drm, "GEN6_STOLEN_RESERVED = %08x\n", reg_val);

        if (!(reg_val & GEN6_STOLEN_RESERVED_ENABLE))
                return;

        if (!(reg_val & GEN6_STOLEN_RESERVED_ADDR_MASK))
                return;

        *base = reg_val & GEN6_STOLEN_RESERVED_ADDR_MASK;
        *size = stolen_top - *base;
}

static void icl_get_stolen_reserved(struct drm_i915_private *i915,
                                    struct intel_uncore *uncore,
                                    resource_size_t *base,
                                    resource_size_t *size)
{
        u64 reg_val = intel_uncore_read64(uncore, GEN6_STOLEN_RESERVED);

        drm_dbg(&i915->drm, "GEN6_STOLEN_RESERVED = 0x%016llx\n", reg_val);

        *base = reg_val & GEN11_STOLEN_RESERVED_ADDR_MASK;

        switch (reg_val & GEN8_STOLEN_RESERVED_SIZE_MASK) {
        case GEN8_STOLEN_RESERVED_1M:
                *size = 1024 * 1024;
                break;
        case GEN8_STOLEN_RESERVED_2M:
                *size = 2 * 1024 * 1024;
                break;
        case GEN8_STOLEN_RESERVED_4M:
                *size = 4 * 1024 * 1024;
                break;
        case GEN8_STOLEN_RESERVED_8M:
                *size = 8 * 1024 * 1024;
                break;
        default:
                *size = 8 * 1024 * 1024;
                MISSING_CASE(reg_val & GEN8_STOLEN_RESERVED_SIZE_MASK);
        }
}

static int i915_gem_init_stolen(struct intel_memory_region *mem)
{
        struct drm_i915_private *i915 = mem->i915;
        struct intel_uncore *uncore = &i915->uncore;
        resource_size_t reserved_base, stolen_top;
        resource_size_t reserved_total, reserved_size;

        mutex_init(&i915->mm.stolen_lock);

        if (intel_vgpu_active(i915)) {
                drm_notice(&i915->drm,
                           "%s, disabling use of stolen memory\n",
                           "iGVT-g active");
                return 0;
        }

        if (intel_vtd_active() && GRAPHICS_VER(i915) < 8) {
                drm_notice(&i915->drm,
                           "%s, disabling use of stolen memory\n",
                           "DMAR active");
                return 0;
        }

        if (resource_size(&mem->region) == 0)
                return 0;

        i915->dsm = mem->region;

        if (i915_adjust_stolen(i915, &i915->dsm))
                return 0;

        GEM_BUG_ON(i915->dsm.start == 0);
        GEM_BUG_ON(i915->dsm.end <= i915->dsm.start);

        stolen_top = i915->dsm.end + 1;
        reserved_base = stolen_top;
        reserved_size = 0;

        switch (GRAPHICS_VER(i915)) {
        case 2:
        case 3:
                break;
        case 4:
                if (!IS_G4X(i915))
                        break;
                fallthrough;
        case 5:
                g4x_get_stolen_reserved(i915, uncore,
                                        &reserved_base, &reserved_size);
                break;
        case 6:
                gen6_get_stolen_reserved(i915, uncore,
                                         &reserved_base, &reserved_size);
                break;
        case 7:
                if (IS_VALLEYVIEW(i915))
                        vlv_get_stolen_reserved(i915, uncore,
                                                &reserved_base, &reserved_size);
                else
                        gen7_get_stolen_reserved(i915, uncore,
                                                 &reserved_base, &reserved_size);
                break;
        case 8:
        case 9:
                if (IS_LP(i915))
                        chv_get_stolen_reserved(i915, uncore,
                                                &reserved_base, &reserved_size);
                else
                        bdw_get_stolen_reserved(i915, uncore,
                                                &reserved_base, &reserved_size);
                break;
        default:
                MISSING_CASE(GRAPHICS_VER(i915));
                fallthrough;
        case 11:
        case 12:
                icl_get_stolen_reserved(i915, uncore,
                                        &reserved_base,
                                        &reserved_size);
                break;
        }

        /*
         * Our expectation is that the reserved space is at the top of the
         * stolen region and *never* at the bottom. If we see !reserved_base,
         * it likely means we failed to read the registers correctly.
         */
        if (!reserved_base) {
                drm_err(&i915->drm,
                        "inconsistent reservation %pa + %pa; ignoring\n",
                        &reserved_base, &reserved_size);
                reserved_base = stolen_top;
                reserved_size = 0;
        }

        i915->dsm_reserved =
                (struct resource)DEFINE_RES_MEM(reserved_base, reserved_size);

        if (!resource_contains(&i915->dsm, &i915->dsm_reserved)) {
                drm_err(&i915->drm,
                        "Stolen reserved area %pR outside stolen memory %pR\n",
                        &i915->dsm_reserved, &i915->dsm);
                return 0;
        }

        /* It is possible for the reserved area to end before the end of stolen
         * memory, so just consider the start. */
        reserved_total = stolen_top - reserved_base;

        drm_dbg(&i915->drm,
                "Memory reserved for graphics device: %lluK, usable: %lluK\n",
                (u64)resource_size(&i915->dsm) >> 10,
                ((u64)resource_size(&i915->dsm) - reserved_total) >> 10);

        i915->stolen_usable_size =
                resource_size(&i915->dsm) - reserved_total;

        /* Basic memrange allocator for stolen space. */
        drm_mm_init(&i915->mm.stolen, 0, i915->stolen_usable_size);

        return 0;
}

static void dbg_poison(struct i915_ggtt *ggtt,
                       dma_addr_t addr, resource_size_t size,
                       u8 x)
{
#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM)
        if (!drm_mm_node_allocated(&ggtt->error_capture))
                return;

        if (ggtt->vm.bind_async_flags & I915_VMA_GLOBAL_BIND)
                return; /* beware stop_machine() inversion */

        GEM_BUG_ON(!IS_ALIGNED(size, PAGE_SIZE));

        mutex_lock(&ggtt->error_mutex);
        while (size) {
                void __iomem *s;

                ggtt->vm.insert_page(&ggtt->vm, addr,
                                     ggtt->error_capture.start,
                                     I915_CACHE_NONE, 0);
                mb();

                s = io_mapping_map_wc(&ggtt->iomap,
                                      ggtt->error_capture.start,
                                      PAGE_SIZE);
                memset_io(s, x, PAGE_SIZE);
                io_mapping_unmap(s);

                addr += PAGE_SIZE;
                size -= PAGE_SIZE;
        }
        mb();
        ggtt->vm.clear_range(&ggtt->vm, ggtt->error_capture.start, PAGE_SIZE);
        mutex_unlock(&ggtt->error_mutex);
#endif
}

static struct sg_table *
i915_pages_create_for_stolen(struct drm_device *dev,
                             resource_size_t offset, resource_size_t size)
{
        struct drm_i915_private *i915 = to_i915(dev);
        struct sg_table *st;
        struct scatterlist *sg;

        GEM_BUG_ON(range_overflows(offset, size, resource_size(&i915->dsm)));

        /* 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 ERR_PTR(-ENOMEM);

        if (sg_alloc_table(st, 1, GFP_KERNEL)) {
                kfree(st);
                return ERR_PTR(-ENOMEM);
        }

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

        sg_dma_address(sg) = (dma_addr_t)i915->dsm.start + offset;
        sg_dma_len(sg) = size;

        return st;
}

static int i915_gem_object_get_pages_stolen(struct drm_i915_gem_object *obj)
{
        struct sg_table *pages =
                i915_pages_create_for_stolen(obj->base.dev,
                                             obj->stolen->start,
                                             obj->stolen->size);
        if (IS_ERR(pages))
                return PTR_ERR(pages);

        dbg_poison(&to_i915(obj->base.dev)->ggtt,
                   sg_dma_address(pages->sgl),
                   sg_dma_len(pages->sgl),
                   POISON_INUSE);

        __i915_gem_object_set_pages(obj, pages, obj->stolen->size);

        return 0;
}

static void i915_gem_object_put_pages_stolen(struct drm_i915_gem_object *obj,
                                             struct sg_table *pages)
{
        /* Should only be called from i915_gem_object_release_stolen() */

        dbg_poison(&to_i915(obj->base.dev)->ggtt,
                   sg_dma_address(pages->sgl),
                   sg_dma_len(pages->sgl),
                   POISON_FREE);

        sg_free_table(pages);
        kfree(pages);
}

static void
i915_gem_object_release_stolen(struct drm_i915_gem_object *obj)
{
        struct drm_i915_private *i915 = to_i915(obj->base.dev);
        struct drm_mm_node *stolen = fetch_and_zero(&obj->stolen);

        GEM_BUG_ON(!stolen);
        i915_gem_stolen_remove_node(i915, stolen);
        kfree(stolen);

        i915_gem_object_release_memory_region(obj);
}

static const struct drm_i915_gem_object_ops i915_gem_object_stolen_ops = {
        .name = "i915_gem_object_stolen",
        .get_pages = i915_gem_object_get_pages_stolen,
        .put_pages = i915_gem_object_put_pages_stolen,
        .release = i915_gem_object_release_stolen,
};

static int __i915_gem_object_create_stolen(struct intel_memory_region *mem,
                                           struct drm_i915_gem_object *obj,
                                           struct drm_mm_node *stolen)
{
        static struct lock_class_key lock_class;
        unsigned int cache_level;
        unsigned int flags;
        int err;

        /*
         * Stolen objects are always physically contiguous since we just
         * allocate one big block underneath using the drm_mm range allocator.
         */
        flags = I915_BO_ALLOC_CONTIGUOUS;

        drm_gem_private_object_init(&mem->i915->drm, &obj->base, stolen->size);
        i915_gem_object_init(obj, &i915_gem_object_stolen_ops, &lock_class, flags);

        obj->stolen = stolen;
        obj->read_domains = I915_GEM_DOMAIN_CPU | I915_GEM_DOMAIN_GTT;
        cache_level = HAS_LLC(mem->i915) ? I915_CACHE_LLC : I915_CACHE_NONE;
        i915_gem_object_set_cache_coherency(obj, cache_level);

        if (WARN_ON(!i915_gem_object_trylock(obj)))
                return -EBUSY;

        i915_gem_object_init_memory_region(obj, mem);

        err = i915_gem_object_pin_pages(obj);
        if (err)
                i915_gem_object_release_memory_region(obj);
        i915_gem_object_unlock(obj);

        return err;
}

static int _i915_gem_object_stolen_init(struct intel_memory_region *mem,
                                        struct drm_i915_gem_object *obj,
                                        resource_size_t size,
                                        resource_size_t page_size,
                                        unsigned int flags)
{
        struct drm_i915_private *i915 = mem->i915;
        struct drm_mm_node *stolen;
        int ret;

        if (!drm_mm_initialized(&i915->mm.stolen))
                return -ENODEV;

        if (size == 0)
                return -EINVAL;

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

        ret = i915_gem_stolen_insert_node(i915, stolen, size,
                                          mem->min_page_size);
        if (ret)
                goto err_free;

        ret = __i915_gem_object_create_stolen(mem, obj, stolen);
        if (ret)
                goto err_remove;

        return 0;

err_remove:
        i915_gem_stolen_remove_node(i915, stolen);
err_free:
        kfree(stolen);
        return ret;
}

struct drm_i915_gem_object *
i915_gem_object_create_stolen(struct drm_i915_private *i915,
                              resource_size_t size)
{
        return i915_gem_object_create_region(i915->mm.stolen_region, size, 0, 0);
}

static int init_stolen_smem(struct intel_memory_region *mem)
{
        /*
         * Initialise stolen early so that we may reserve preallocated
         * objects for the BIOS to KMS transition.
         */
        return i915_gem_init_stolen(mem);
}

static void release_stolen_smem(struct intel_memory_region *mem)
{
        i915_gem_cleanup_stolen(mem->i915);
}

static const struct intel_memory_region_ops i915_region_stolen_smem_ops = {
        .init = init_stolen_smem,
        .release = release_stolen_smem,
        .init_object = _i915_gem_object_stolen_init,
};

static int init_stolen_lmem(struct intel_memory_region *mem)
{
        int err;

        if (GEM_WARN_ON(resource_size(&mem->region) == 0))
                return -ENODEV;

        if (!io_mapping_init_wc(&mem->iomap,
                                mem->io_start,
                                resource_size(&mem->region)))
                return -EIO;

        /*
         * TODO: For stolen lmem we mostly just care about populating the dsm
         * related bits and setting up the drm_mm allocator for the range.
         * Perhaps split up i915_gem_init_stolen() for this.
         */
        err = i915_gem_init_stolen(mem);
        if (err)
                goto err_fini;

        return 0;

err_fini:
        io_mapping_fini(&mem->iomap);
        return err;
}

static void release_stolen_lmem(struct intel_memory_region *mem)
{
        io_mapping_fini(&mem->iomap);
        i915_gem_cleanup_stolen(mem->i915);
}

static const struct intel_memory_region_ops i915_region_stolen_lmem_ops = {
        .init = init_stolen_lmem,
        .release = release_stolen_lmem,
        .init_object = _i915_gem_object_stolen_init,
};

struct intel_memory_region *
i915_gem_stolen_lmem_setup(struct drm_i915_private *i915, u16 type,
                           u16 instance)
{
        struct intel_uncore *uncore = &i915->uncore;
        struct pci_dev *pdev = to_pci_dev(i915->drm.dev);
        struct intel_memory_region *mem;
        resource_size_t io_start;
        resource_size_t lmem_size;
        u64 lmem_base;

        lmem_base = intel_uncore_read64(uncore, GEN12_DSMBASE);
        if (GEM_WARN_ON(lmem_base >= pci_resource_len(pdev, 2)))
                return ERR_PTR(-ENODEV);

        lmem_size = pci_resource_len(pdev, 2) - lmem_base;
        io_start = pci_resource_start(pdev, 2) + lmem_base;

        mem = intel_memory_region_create(i915, lmem_base, lmem_size,
                                         I915_GTT_PAGE_SIZE_4K, io_start,
                                         type, instance,
                                         &i915_region_stolen_lmem_ops);
        if (IS_ERR(mem))
                return mem;

        /*
         * TODO: consider creating common helper to just print all the
         * interesting stuff from intel_memory_region, which we can use for all
         * our probed regions.
         */

        drm_dbg(&i915->drm, "Stolen Local memory IO start: %pa\n",
                &mem->io_start);

        intel_memory_region_set_name(mem, "stolen-local");

        mem->private = true;

        return mem;
}

struct intel_memory_region*
i915_gem_stolen_smem_setup(struct drm_i915_private *i915, u16 type,
                           u16 instance)
{
        struct intel_memory_region *mem;

        mem = intel_memory_region_create(i915,
                                         intel_graphics_stolen_res.start,
                                         resource_size(&intel_graphics_stolen_res),
                                         PAGE_SIZE, 0, type, instance,
                                         &i915_region_stolen_smem_ops);
        if (IS_ERR(mem))
                return mem;

        intel_memory_region_set_name(mem, "stolen-system");

        mem->private = true;
        return mem;
}

struct drm_i915_gem_object *
i915_gem_object_create_stolen_for_preallocated(struct drm_i915_private *i915,
                                               resource_size_t stolen_offset,
                                               resource_size_t size)
{
        struct intel_memory_region *mem = i915->mm.stolen_region;
        struct drm_i915_gem_object *obj;
        struct drm_mm_node *stolen;
        int ret;

        if (!drm_mm_initialized(&i915->mm.stolen))
                return ERR_PTR(-ENODEV);

        drm_dbg(&i915->drm,
                "creating preallocated stolen object: stolen_offset=%pa, size=%pa\n",
                &stolen_offset, &size);

        /* KISS and expect everything to be page-aligned */
        if (GEM_WARN_ON(size == 0) ||
            GEM_WARN_ON(!IS_ALIGNED(size, mem->min_page_size)) ||
            GEM_WARN_ON(!IS_ALIGNED(stolen_offset, mem->min_page_size)))
                return ERR_PTR(-EINVAL);

        stolen = kzalloc(sizeof(*stolen), GFP_KERNEL);
        if (!stolen)
                return ERR_PTR(-ENOMEM);

        stolen->start = stolen_offset;
        stolen->size = size;
        mutex_lock(&i915->mm.stolen_lock);
        ret = drm_mm_reserve_node(&i915->mm.stolen, stolen);
        mutex_unlock(&i915->mm.stolen_lock);
        if (ret)
                goto err_free;

        obj = i915_gem_object_alloc();
        if (!obj) {
                ret = -ENOMEM;
                goto err_stolen;
        }

        ret = __i915_gem_object_create_stolen(mem, obj, stolen);
        if (ret)
                goto err_object_free;

        i915_gem_object_set_cache_coherency(obj, I915_CACHE_NONE);
        return obj;

err_object_free:
        i915_gem_object_free(obj);
err_stolen:
        i915_gem_stolen_remove_node(i915, stolen);
err_free:
        kfree(stolen);
        return ERR_PTR(ret);
}

bool i915_gem_object_is_stolen(const struct drm_i915_gem_object *obj)
{
        return obj->ops == &i915_gem_object_stolen_ops;
}