/*
 * Copyright 2009 Jerome Glisse.
 * All Rights Reserved.
 *
 * 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, sub license, 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 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 NON-INFRINGEMENT. IN NO EVENT SHALL
 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS 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.
 *
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial portions
 * of the Software.
 *
 */
/*
 * Authors:
 *    Jerome Glisse <glisse@freedesktop.org>
 *    Thomas Hellstrom <thomas-at-tungstengraphics-dot-com>
 *    Dave Airlie
 */

#include <linux/dma-mapping.h>
#include <linux/iommu.h>
#include <linux/hmm.h>
#include <linux/pagemap.h>
#include <linux/sched/task.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/swap.h>
#include <linux/swiotlb.h>

#include <drm/ttm/ttm_bo_api.h>
#include <drm/ttm/ttm_bo_driver.h>
#include <drm/ttm/ttm_placement.h>
#include <drm/ttm/ttm_module.h>
#include <drm/ttm/ttm_page_alloc.h>

#include <drm/drm_debugfs.h>
#include <drm/amdgpu_drm.h>

#include "amdgpu.h"
#include "amdgpu_object.h"
#include "amdgpu_trace.h"
#include "amdgpu_amdkfd.h"
#include "amdgpu_sdma.h"
#include "bif/bif_4_1_d.h"

static int amdgpu_map_buffer(struct ttm_buffer_object *bo,
                             struct ttm_mem_reg *mem, unsigned num_pages,
                             uint64_t offset, unsigned window,
                             struct amdgpu_ring *ring,
                             uint64_t *addr);

static int amdgpu_ttm_debugfs_init(struct amdgpu_device *adev);
static void amdgpu_ttm_debugfs_fini(struct amdgpu_device *adev);

static int amdgpu_invalidate_caches(struct ttm_bo_device *bdev, uint32_t flags)
{
        return 0;
}

/**
 * amdgpu_init_mem_type - Initialize a memory manager for a specific type of
 * memory request.
 *
 * @bdev: The TTM BO device object (contains a reference to amdgpu_device)
 * @type: The type of memory requested
 * @man: The memory type manager for each domain
 *
 * This is called by ttm_bo_init_mm() when a buffer object is being
 * initialized.
 */
static int amdgpu_init_mem_type(struct ttm_bo_device *bdev, uint32_t type,
                                struct ttm_mem_type_manager *man)
{
        struct amdgpu_device *adev;

        adev = amdgpu_ttm_adev(bdev);

        switch (type) {
        case TTM_PL_SYSTEM:
                /* System memory */
                man->flags = TTM_MEMTYPE_FLAG_MAPPABLE;
                man->available_caching = TTM_PL_MASK_CACHING;
                man->default_caching = TTM_PL_FLAG_CACHED;
                break;
        case TTM_PL_TT:
                /* GTT memory  */
                man->func = &amdgpu_gtt_mgr_func;
                man->gpu_offset = adev->gmc.gart_start;
                man->available_caching = TTM_PL_MASK_CACHING;
                man->default_caching = TTM_PL_FLAG_CACHED;
                man->flags = TTM_MEMTYPE_FLAG_MAPPABLE | TTM_MEMTYPE_FLAG_CMA;
                break;
        case TTM_PL_VRAM:
                /* "On-card" video ram */
                man->func = &amdgpu_vram_mgr_func;
                man->gpu_offset = adev->gmc.vram_start;
                man->flags = TTM_MEMTYPE_FLAG_FIXED |
                             TTM_MEMTYPE_FLAG_MAPPABLE;
                man->available_caching = TTM_PL_FLAG_UNCACHED | TTM_PL_FLAG_WC;
                man->default_caching = TTM_PL_FLAG_WC;
                break;
        case AMDGPU_PL_GDS:
        case AMDGPU_PL_GWS:
        case AMDGPU_PL_OA:
                /* On-chip GDS memory*/
                man->func = &ttm_bo_manager_func;
                man->gpu_offset = 0;
                man->flags = TTM_MEMTYPE_FLAG_FIXED | TTM_MEMTYPE_FLAG_CMA;
                man->available_caching = TTM_PL_FLAG_UNCACHED;
                man->default_caching = TTM_PL_FLAG_UNCACHED;
                break;
        default:
                DRM_ERROR("Unsupported memory type %u\n", (unsigned)type);
                return -EINVAL;
        }
        return 0;
}

/**
 * amdgpu_evict_flags - Compute placement flags
 *
 * @bo: The buffer object to evict
 * @placement: Possible destination(s) for evicted BO
 *
 * Fill in placement data when ttm_bo_evict() is called
 */
static void amdgpu_evict_flags(struct ttm_buffer_object *bo,
                                struct ttm_placement *placement)
{
        struct amdgpu_device *adev = amdgpu_ttm_adev(bo->bdev);
        struct amdgpu_bo *abo;
        static const struct ttm_place placements = {
                .fpfn = 0,
                .lpfn = 0,
                .flags = TTM_PL_MASK_CACHING | TTM_PL_FLAG_SYSTEM
        };

        /* Don't handle scatter gather BOs */
        if (bo->type == ttm_bo_type_sg) {
                placement->num_placement = 0;
                placement->num_busy_placement = 0;
                return;
        }

        /* Object isn't an AMDGPU object so ignore */
        if (!amdgpu_bo_is_amdgpu_bo(bo)) {
                placement->placement = &placements;
                placement->busy_placement = &placements;
                placement->num_placement = 1;
                placement->num_busy_placement = 1;
                return;
        }

        abo = ttm_to_amdgpu_bo(bo);
        switch (bo->mem.mem_type) {
        case AMDGPU_PL_GDS:
        case AMDGPU_PL_GWS:
        case AMDGPU_PL_OA:
                placement->num_placement = 0;
                placement->num_busy_placement = 0;
                return;

        case TTM_PL_VRAM:
                if (!adev->mman.buffer_funcs_enabled) {
                        /* Move to system memory */
                        amdgpu_bo_placement_from_domain(abo, AMDGPU_GEM_DOMAIN_CPU);
                } else if (!amdgpu_gmc_vram_full_visible(&adev->gmc) &&
                           !(abo->flags & AMDGPU_GEM_CREATE_CPU_ACCESS_REQUIRED) &&
                           amdgpu_bo_in_cpu_visible_vram(abo)) {

                        /* Try evicting to the CPU inaccessible part of VRAM
                         * first, but only set GTT as busy placement, so this
                         * BO will be evicted to GTT rather than causing other
                         * BOs to be evicted from VRAM
                         */
                        amdgpu_bo_placement_from_domain(abo, AMDGPU_GEM_DOMAIN_VRAM |
                                                         AMDGPU_GEM_DOMAIN_GTT);
                        abo->placements[0].fpfn = adev->gmc.visible_vram_size >> PAGE_SHIFT;
                        abo->placements[0].lpfn = 0;
                        abo->placement.busy_placement = &abo->placements[1];
                        abo->placement.num_busy_placement = 1;
                } else {
                        /* Move to GTT memory */
                        amdgpu_bo_placement_from_domain(abo, AMDGPU_GEM_DOMAIN_GTT);
                }
                break;
        case TTM_PL_TT:
        default:
                amdgpu_bo_placement_from_domain(abo, AMDGPU_GEM_DOMAIN_CPU);
                break;
        }
        *placement = abo->placement;
}

/**
 * amdgpu_verify_access - Verify access for a mmap call
 *
 * @bo: The buffer object to map
 * @filp: The file pointer from the process performing the mmap
 *
 * This is called by ttm_bo_mmap() to verify whether a process
 * has the right to mmap a BO to their process space.
 */
static int amdgpu_verify_access(struct ttm_buffer_object *bo, struct file *filp)
{
        struct amdgpu_bo *abo = ttm_to_amdgpu_bo(bo);

        /*
         * Don't verify access for KFD BOs. They don't have a GEM
         * object associated with them.
         */
        if (abo->kfd_bo)
                return 0;

        if (amdgpu_ttm_tt_get_usermm(bo->ttm))
                return -EPERM;
        return drm_vma_node_verify_access(&abo->gem_base.vma_node,
                                          filp->private_data);
}

/**
 * amdgpu_move_null - Register memory for a buffer object
 *
 * @bo: The bo to assign the memory to
 * @new_mem: The memory to be assigned.
 *
 * Assign the memory from new_mem to the memory of the buffer object bo.
 */
static void amdgpu_move_null(struct ttm_buffer_object *bo,
                             struct ttm_mem_reg *new_mem)
{
        struct ttm_mem_reg *old_mem = &bo->mem;

        BUG_ON(old_mem->mm_node != NULL);
        *old_mem = *new_mem;
        new_mem->mm_node = NULL;
}

/**
 * amdgpu_mm_node_addr - Compute the GPU relative offset of a GTT buffer.
 *
 * @bo: The bo to assign the memory to.
 * @mm_node: Memory manager node for drm allocator.
 * @mem: The region where the bo resides.
 *
 */
static uint64_t amdgpu_mm_node_addr(struct ttm_buffer_object *bo,
                                    struct drm_mm_node *mm_node,
                                    struct ttm_mem_reg *mem)
{
        uint64_t addr = 0;

        if (mm_node->start != AMDGPU_BO_INVALID_OFFSET) {
                addr = mm_node->start << PAGE_SHIFT;
                addr += bo->bdev->man[mem->mem_type].gpu_offset;
        }
        return addr;
}

/**
 * amdgpu_find_mm_node - Helper function finds the drm_mm_node corresponding to
 * @offset. It also modifies the offset to be within the drm_mm_node returned
 *
 * @mem: The region where the bo resides.
 * @offset: The offset that drm_mm_node is used for finding.
 *
 */
static struct drm_mm_node *amdgpu_find_mm_node(struct ttm_mem_reg *mem,
                                               unsigned long *offset)
{
        struct drm_mm_node *mm_node = mem->mm_node;

        while (*offset >= (mm_node->size << PAGE_SHIFT)) {
                *offset -= (mm_node->size << PAGE_SHIFT);
                ++mm_node;
        }
        return mm_node;
}

/**
 * amdgpu_copy_ttm_mem_to_mem - Helper function for copy
 *
 * The function copies @size bytes from {src->mem + src->offset} to
 * {dst->mem + dst->offset}. src->bo and dst->bo could be same BO for a
 * move and different for a BO to BO copy.
 *
 * @f: Returns the last fence if multiple jobs are submitted.
 */
int amdgpu_ttm_copy_mem_to_mem(struct amdgpu_device *adev,
                               struct amdgpu_copy_mem *src,
                               struct amdgpu_copy_mem *dst,
                               uint64_t size,
                               struct reservation_object *resv,
                               struct dma_fence **f)
{
        struct amdgpu_ring *ring = adev->mman.buffer_funcs_ring;
        struct drm_mm_node *src_mm, *dst_mm;
        uint64_t src_node_start, dst_node_start, src_node_size,
                 dst_node_size, src_page_offset, dst_page_offset;
        struct dma_fence *fence = NULL;
        int r = 0;
        const uint64_t GTT_MAX_BYTES = (AMDGPU_GTT_MAX_TRANSFER_SIZE *
                                        AMDGPU_GPU_PAGE_SIZE);

        if (!adev->mman.buffer_funcs_enabled) {
                DRM_ERROR("Trying to move memory with ring turned off.\n");
                return -EINVAL;
        }

        src_mm = amdgpu_find_mm_node(src->mem, &src->offset);
        src_node_start = amdgpu_mm_node_addr(src->bo, src_mm, src->mem) +
                                             src->offset;
        src_node_size = (src_mm->size << PAGE_SHIFT) - src->offset;
        src_page_offset = src_node_start & (PAGE_SIZE - 1);

        dst_mm = amdgpu_find_mm_node(dst->mem, &dst->offset);
        dst_node_start = amdgpu_mm_node_addr(dst->bo, dst_mm, dst->mem) +
                                             dst->offset;
        dst_node_size = (dst_mm->size << PAGE_SHIFT) - dst->offset;
        dst_page_offset = dst_node_start & (PAGE_SIZE - 1);

        mutex_lock(&adev->mman.gtt_window_lock);

        while (size) {
                unsigned long cur_size;
                uint64_t from = src_node_start, to = dst_node_start;
                struct dma_fence *next;

                /* Copy size cannot exceed GTT_MAX_BYTES. So if src or dst
                 * begins at an offset, then adjust the size accordingly
                 */
                cur_size = min3(min(src_node_size, dst_node_size), size,
                                GTT_MAX_BYTES);
                if (cur_size + src_page_offset > GTT_MAX_BYTES ||
                    cur_size + dst_page_offset > GTT_MAX_BYTES)
                        cur_size -= max(src_page_offset, dst_page_offset);

                /* Map only what needs to be accessed. Map src to window 0 and
                 * dst to window 1
                 */
                if (src->mem->start == AMDGPU_BO_INVALID_OFFSET) {
                        r = amdgpu_map_buffer(src->bo, src->mem,
                                        PFN_UP(cur_size + src_page_offset),
                                        src_node_start, 0, ring,
                                        &from);
                        if (r)
                                goto error;
                        /* Adjust the offset because amdgpu_map_buffer returns
                         * start of mapped page
                         */
                        from += src_page_offset;
                }

                if (dst->mem->start == AMDGPU_BO_INVALID_OFFSET) {
                        r = amdgpu_map_buffer(dst->bo, dst->mem,
                                        PFN_UP(cur_size + dst_page_offset),
                                        dst_node_start, 1, ring,
                                        &to);
                        if (r)
                                goto error;
                        to += dst_page_offset;
                }

                r = amdgpu_copy_buffer(ring, from, to, cur_size,
                                       resv, &next, false, true);
                if (r)
                        goto error;

                dma_fence_put(fence);
                fence = next;

                size -= cur_size;
                if (!size)
                        break;

                src_node_size -= cur_size;
                if (!src_node_size) {
                        src_node_start = amdgpu_mm_node_addr(src->bo, ++src_mm,
                                                             src->mem);
                        src_node_size = (src_mm->size << PAGE_SHIFT);
                        src_page_offset = 0;
                } else {
                        src_node_start += cur_size;
                        src_page_offset = src_node_start & (PAGE_SIZE - 1);
                }
                dst_node_size -= cur_size;
                if (!dst_node_size) {
                        dst_node_start = amdgpu_mm_node_addr(dst->bo, ++dst_mm,
                                                             dst->mem);
                        dst_node_size = (dst_mm->size << PAGE_SHIFT);
                        dst_page_offset = 0;
                } else {
                        dst_node_start += cur_size;
                        dst_page_offset = dst_node_start & (PAGE_SIZE - 1);
                }
        }
error:
        mutex_unlock(&adev->mman.gtt_window_lock);
        if (f)
                *f = dma_fence_get(fence);
        dma_fence_put(fence);
        return r;
}

/**
 * amdgpu_move_blit - Copy an entire buffer to another buffer
 *
 * This is a helper called by amdgpu_bo_move() and amdgpu_move_vram_ram() to
 * help move buffers to and from VRAM.
 */
static int amdgpu_move_blit(struct ttm_buffer_object *bo,
                            bool evict, bool no_wait_gpu,
                            struct ttm_mem_reg *new_mem,
                            struct ttm_mem_reg *old_mem)
{
        struct amdgpu_device *adev = amdgpu_ttm_adev(bo->bdev);
        struct amdgpu_copy_mem src, dst;
        struct dma_fence *fence = NULL;
        int r;

        src.bo = bo;
        dst.bo = bo;
        src.mem = old_mem;
        dst.mem = new_mem;
        src.offset = 0;
        dst.offset = 0;

        r = amdgpu_ttm_copy_mem_to_mem(adev, &src, &dst,
                                       new_mem->num_pages << PAGE_SHIFT,
                                       bo->resv, &fence);
        if (r)
                goto error;

        /* Always block for VM page tables before committing the new location */
        if (bo->type == ttm_bo_type_kernel)
                r = ttm_bo_move_accel_cleanup(bo, fence, true, new_mem);
        else
                r = ttm_bo_pipeline_move(bo, fence, evict, new_mem);
        dma_fence_put(fence);
        return r;

error:
        if (fence)
                dma_fence_wait(fence, false);
        dma_fence_put(fence);
        return r;
}

/**
 * amdgpu_move_vram_ram - Copy VRAM buffer to RAM buffer
 *
 * Called by amdgpu_bo_move().
 */
static int amdgpu_move_vram_ram(struct ttm_buffer_object *bo, bool evict,
                                struct ttm_operation_ctx *ctx,
                                struct ttm_mem_reg *new_mem)
{
        struct amdgpu_device *adev;
        struct ttm_mem_reg *old_mem = &bo->mem;
        struct ttm_mem_reg tmp_mem;
        struct ttm_place placements;
        struct ttm_placement placement;
        int r;

        adev = amdgpu_ttm_adev(bo->bdev);

        /* create space/pages for new_mem in GTT space */
        tmp_mem = *new_mem;
        tmp_mem.mm_node = NULL;
        placement.num_placement = 1;
        placement.placement = &placements;
        placement.num_busy_placement = 1;
        placement.busy_placement = &placements;
        placements.fpfn = 0;
        placements.lpfn = 0;
        placements.flags = TTM_PL_MASK_CACHING | TTM_PL_FLAG_TT;
        r = ttm_bo_mem_space(bo, &placement, &tmp_mem, ctx);
        if (unlikely(r)) {
                pr_err("Failed to find GTT space for blit from VRAM\n");
                return r;
        }

        /* set caching flags */
        r = ttm_tt_set_placement_caching(bo->ttm, tmp_mem.placement);
        if (unlikely(r)) {
                goto out_cleanup;
        }

        /* Bind the memory to the GTT space */
        r = ttm_tt_bind(bo->ttm, &tmp_mem, ctx);
        if (unlikely(r)) {
                goto out_cleanup;
        }

        /* blit VRAM to GTT */
        r = amdgpu_move_blit(bo, evict, ctx->no_wait_gpu, &tmp_mem, old_mem);
        if (unlikely(r)) {
                goto out_cleanup;
        }

        /* move BO (in tmp_mem) to new_mem */
        r = ttm_bo_move_ttm(bo, ctx, new_mem);
out_cleanup:
        ttm_bo_mem_put(bo, &tmp_mem);
        return r;
}

/**
 * amdgpu_move_ram_vram - Copy buffer from RAM to VRAM
 *
 * Called by amdgpu_bo_move().
 */
static int amdgpu_move_ram_vram(struct ttm_buffer_object *bo, bool evict,
                                struct ttm_operation_ctx *ctx,
                                struct ttm_mem_reg *new_mem)
{
        struct amdgpu_device *adev;
        struct ttm_mem_reg *old_mem = &bo->mem;
        struct ttm_mem_reg tmp_mem;
        struct ttm_placement placement;
        struct ttm_place placements;
        int r;

        adev = amdgpu_ttm_adev(bo->bdev);

        /* make space in GTT for old_mem buffer */
        tmp_mem = *new_mem;
        tmp_mem.mm_node = NULL;
        placement.num_placement = 1;
        placement.placement = &placements;
        placement.num_busy_placement = 1;
        placement.busy_placement = &placements;
        placements.fpfn = 0;
        placements.lpfn = 0;
        placements.flags = TTM_PL_MASK_CACHING | TTM_PL_FLAG_TT;
        r = ttm_bo_mem_space(bo, &placement, &tmp_mem, ctx);
        if (unlikely(r)) {
                pr_err("Failed to find GTT space for blit to VRAM\n");
                return r;
        }

        /* move/bind old memory to GTT space */
        r = ttm_bo_move_ttm(bo, ctx, &tmp_mem);
        if (unlikely(r)) {
                goto out_cleanup;
        }

        /* copy to VRAM */
        r = amdgpu_move_blit(bo, evict, ctx->no_wait_gpu, new_mem, old_mem);
        if (unlikely(r)) {
                goto out_cleanup;
        }
out_cleanup:
        ttm_bo_mem_put(bo, &tmp_mem);
        return r;
}

/**
 * amdgpu_mem_visible - Check that memory can be accessed by ttm_bo_move_memcpy
 *
 * Called by amdgpu_bo_move()
 */
static bool amdgpu_mem_visible(struct amdgpu_device *adev,
                               struct ttm_mem_reg *mem)
{
        struct drm_mm_node *nodes = mem->mm_node;

        if (mem->mem_type == TTM_PL_SYSTEM ||
            mem->mem_type == TTM_PL_TT)
                return true;
        if (mem->mem_type != TTM_PL_VRAM)
                return false;

        /* ttm_mem_reg_ioremap only supports contiguous memory */
        if (nodes->size != mem->num_pages)
                return false;

        return ((nodes->start + nodes->size) << PAGE_SHIFT)
                <= adev->gmc.visible_vram_size;
}

/**
 * amdgpu_bo_move - Move a buffer object to a new memory location
 *
 * Called by ttm_bo_handle_move_mem()
 */
static int amdgpu_bo_move(struct ttm_buffer_object *bo, bool evict,
                          struct ttm_operation_ctx *ctx,
                          struct ttm_mem_reg *new_mem)
{
        struct amdgpu_device *adev;
        struct amdgpu_bo *abo;
        struct ttm_mem_reg *old_mem = &bo->mem;
        int r;

        /* Can't move a pinned BO */
        abo = ttm_to_amdgpu_bo(bo);
        if (WARN_ON_ONCE(abo->pin_count > 0))
                return -EINVAL;

        adev = amdgpu_ttm_adev(bo->bdev);

        if (old_mem->mem_type == TTM_PL_SYSTEM && bo->ttm == NULL) {
                amdgpu_move_null(bo, new_mem);
                return 0;
        }
        if ((old_mem->mem_type == TTM_PL_TT &&
             new_mem->mem_type == TTM_PL_SYSTEM) ||
            (old_mem->mem_type == TTM_PL_SYSTEM &&
             new_mem->mem_type == TTM_PL_TT)) {
                /* bind is enough */
                amdgpu_move_null(bo, new_mem);
                return 0;
        }
        if (old_mem->mem_type == AMDGPU_PL_GDS ||
            old_mem->mem_type == AMDGPU_PL_GWS ||
            old_mem->mem_type == AMDGPU_PL_OA ||
            new_mem->mem_type == AMDGPU_PL_GDS ||
            new_mem->mem_type == AMDGPU_PL_GWS ||
            new_mem->mem_type == AMDGPU_PL_OA) {
                /* Nothing to save here */
                amdgpu_move_null(bo, new_mem);
                return 0;
        }

        if (!adev->mman.buffer_funcs_enabled) {
                r = -ENODEV;
                goto memcpy;
        }

        if (old_mem->mem_type == TTM_PL_VRAM &&
            new_mem->mem_type == TTM_PL_SYSTEM) {
                r = amdgpu_move_vram_ram(bo, evict, ctx, new_mem);
        } else if (old_mem->mem_type == TTM_PL_SYSTEM &&
                   new_mem->mem_type == TTM_PL_VRAM) {
                r = amdgpu_move_ram_vram(bo, evict, ctx, new_mem);
        } else {
                r = amdgpu_move_blit(bo, evict, ctx->no_wait_gpu,
                                     new_mem, old_mem);
        }

        if (r) {
memcpy:
                /* Check that all memory is CPU accessible */
                if (!amdgpu_mem_visible(adev, old_mem) ||
                    !amdgpu_mem_visible(adev, new_mem)) {
                        pr_err("Move buffer fallback to memcpy unavailable\n");
                        return r;
                }

                r = ttm_bo_move_memcpy(bo, ctx, new_mem);
                if (r)
                        return r;
        }

        if (bo->type == ttm_bo_type_device &&
            new_mem->mem_type == TTM_PL_VRAM &&
            old_mem->mem_type != TTM_PL_VRAM) {
                /* amdgpu_bo_fault_reserve_notify will re-set this if the CPU
                 * accesses the BO after it's moved.
                 */
                abo->flags &= ~AMDGPU_GEM_CREATE_CPU_ACCESS_REQUIRED;
        }

        /* update statistics */
        atomic64_add((u64)bo->num_pages << PAGE_SHIFT, &adev->num_bytes_moved);
        return 0;
}

/**
 * amdgpu_ttm_io_mem_reserve - Reserve a block of memory during a fault
 *
 * Called by ttm_mem_io_reserve() ultimately via ttm_bo_vm_fault()
 */
static int amdgpu_ttm_io_mem_reserve(struct ttm_bo_device *bdev, struct ttm_mem_reg *mem)
{
        struct ttm_mem_type_manager *man = &bdev->man[mem->mem_type];
        struct amdgpu_device *adev = amdgpu_ttm_adev(bdev);
        struct drm_mm_node *mm_node = mem->mm_node;

        mem->bus.addr = NULL;
        mem->bus.offset = 0;
        mem->bus.size = mem->num_pages << PAGE_SHIFT;
        mem->bus.base = 0;
        mem->bus.is_iomem = false;
        if (!(man->flags & TTM_MEMTYPE_FLAG_MAPPABLE))
                return -EINVAL;
        switch (mem->mem_type) {
        case TTM_PL_SYSTEM:
                /* system memory */
                return 0;
        case TTM_PL_TT:
                break;
        case TTM_PL_VRAM:
                mem->bus.offset = mem->start << PAGE_SHIFT;
                /* check if it's visible */
                if ((mem->bus.offset + mem->bus.size) > adev->gmc.visible_vram_size)
                        return -EINVAL;
                /* Only physically contiguous buffers apply. In a contiguous
                 * buffer, size of the first mm_node would match the number of
                 * pages in ttm_mem_reg.
                 */
                if (adev->mman.aper_base_kaddr &&
                    (mm_node->size == mem->num_pages))
                        mem->bus.addr = (u8 *)adev->mman.aper_base_kaddr +
                                        mem->bus.offset;

                mem->bus.base = adev->gmc.aper_base;
                mem->bus.is_iomem = true;
                break;
        default:
                return -EINVAL;
        }
        return 0;
}

static void amdgpu_ttm_io_mem_free(struct ttm_bo_device *bdev, struct ttm_mem_reg *mem)
{
}

static unsigned long amdgpu_ttm_io_mem_pfn(struct ttm_buffer_object *bo,
                                           unsigned long page_offset)
{
        struct drm_mm_node *mm;
        unsigned long offset = (page_offset << PAGE_SHIFT);

        mm = amdgpu_find_mm_node(&bo->mem, &offset);
        return (bo->mem.bus.base >> PAGE_SHIFT) + mm->start +
                (offset >> PAGE_SHIFT);
}

/*
 * TTM backend functions.
 */
struct amdgpu_ttm_tt {
        struct ttm_dma_tt       ttm;
        u64                     offset;
        uint64_t                userptr;
        struct task_struct      *usertask;
        uint32_t                userflags;
#if IS_ENABLED(CONFIG_DRM_AMDGPU_USERPTR)
        struct hmm_range        *range;
#endif
};

/**
 * amdgpu_ttm_tt_get_user_pages - get device accessible pages that back user
 * memory and start HMM tracking CPU page table update
 *
 * Calling function must call amdgpu_ttm_tt_userptr_range_done() once and only
 * once afterwards to stop HMM tracking
 */
#if IS_ENABLED(CONFIG_DRM_AMDGPU_USERPTR)

#define MAX_RETRY_HMM_RANGE_FAULT       16

int amdgpu_ttm_tt_get_user_pages(struct amdgpu_bo *bo, struct page **pages)
{
        struct hmm_mirror *mirror = bo->mn ? &bo->mn->mirror : NULL;
        struct ttm_tt *ttm = bo->tbo.ttm;
        struct amdgpu_ttm_tt *gtt = (void *)ttm;
        struct mm_struct *mm = gtt->usertask->mm;
        unsigned long start = gtt->userptr;
        struct vm_area_struct *vma;
        struct hmm_range *range;
        unsigned long i;
        uint64_t *pfns;
        int retry = 0;
        int r = 0;

        if (!mm) /* Happens during process shutdown */
                return -ESRCH;

        if (unlikely(!mirror)) {
                DRM_DEBUG_DRIVER("Failed to get hmm_mirror\n");
                r = -EFAULT;
                goto out;
        }

        vma = find_vma(mm, start);
        if (unlikely(!vma || start < vma->vm_start)) {
                r = -EFAULT;
                goto out;
        }
        if (unlikely((gtt->userflags & AMDGPU_GEM_USERPTR_ANONONLY) &&
                vma->vm_file)) {
                r = -EPERM;
                goto out;
        }

        range = kzalloc(sizeof(*range), GFP_KERNEL);
        if (unlikely(!range)) {
                r = -ENOMEM;
                goto out;
        }

        pfns = kvmalloc_array(ttm->num_pages, sizeof(*pfns), GFP_KERNEL);
        if (unlikely(!pfns)) {
                r = -ENOMEM;
                goto out_free_ranges;
        }

        amdgpu_hmm_init_range(range);
        range->default_flags = range->flags[HMM_PFN_VALID];
        range->default_flags |= amdgpu_ttm_tt_is_readonly(ttm) ?
                                0 : range->flags[HMM_PFN_WRITE];
        range->pfn_flags_mask = 0;
        range->pfns = pfns;
        hmm_range_register(range, mirror, start,
                           start + ttm->num_pages * PAGE_SIZE, PAGE_SHIFT);

retry:
        /*
         * Just wait for range to be valid, safe to ignore return value as we
         * will use the return value of hmm_range_fault() below under the
         * mmap_sem to ascertain the validity of the range.
         */
        hmm_range_wait_until_valid(range, HMM_RANGE_DEFAULT_TIMEOUT);

        down_read(&mm->mmap_sem);

        r = hmm_range_fault(range, true);
        if (unlikely(r < 0)) {
                if (likely(r == -EAGAIN)) {
                        /*
                         * return -EAGAIN, mmap_sem is dropped
                         */
                        if (retry++ < MAX_RETRY_HMM_RANGE_FAULT)
                                goto retry;
                        else
                                pr_err("Retry hmm fault too many times\n");
                }

                goto out_up_read;
        }

        up_read(&mm->mmap_sem);

        for (i = 0; i < ttm->num_pages; i++) {
                pages[i] = hmm_device_entry_to_page(range, pfns[i]);
                if (unlikely(!pages[i])) {
                        pr_err("Page fault failed for pfn[%lu] = 0x%llx\n",
                               i, pfns[i]);
                        r = -ENOMEM;

                        goto out_free_pfns;
                }
        }

        gtt->range = range;

        return 0;

out_up_read:
        if (likely(r != -EAGAIN))
                up_read(&mm->mmap_sem);
out_free_pfns:
        hmm_range_unregister(range);
        kvfree(pfns);
out_free_ranges:
        kfree(range);
out:
        return r;
}

/**
 * amdgpu_ttm_tt_userptr_range_done - stop HMM track the CPU page table change
 * Check if the pages backing this ttm range have been invalidated
 *
 * Returns: true if pages are still valid
 */
bool amdgpu_ttm_tt_get_user_pages_done(struct ttm_tt *ttm)
{
        struct amdgpu_ttm_tt *gtt = (void *)ttm;
        bool r = false;

        if (!gtt || !gtt->userptr)
                return false;

        DRM_DEBUG_DRIVER("user_pages_done 0x%llx pages 0x%lx\n",
                gtt->userptr, ttm->num_pages);

        WARN_ONCE(!gtt->range || !gtt->range->pfns,
                "No user pages to check\n");

        if (gtt->range) {
                r = hmm_range_valid(gtt->range);
                hmm_range_unregister(gtt->range);

                kvfree(gtt->range->pfns);
                kfree(gtt->range);
                gtt->range = NULL;
        }

        return r;
}
#endif

/**
 * amdgpu_ttm_tt_set_user_pages - Copy pages in, putting old pages as necessary.
 *
 * Called by amdgpu_cs_list_validate(). This creates the page list
 * that backs user memory and will ultimately be mapped into the device
 * address space.
 */
void amdgpu_ttm_tt_set_user_pages(struct ttm_tt *ttm, struct page **pages)
{
        unsigned long i;

        for (i = 0; i < ttm->num_pages; ++i)
                ttm->pages[i] = pages ? pages[i] : NULL;
}

/**
 * amdgpu_ttm_tt_pin_userptr -  prepare the sg table with the user pages
 *
 * Called by amdgpu_ttm_backend_bind()
 **/
static int amdgpu_ttm_tt_pin_userptr(struct ttm_tt *ttm)
{
        struct amdgpu_device *adev = amdgpu_ttm_adev(ttm->bdev);
        struct amdgpu_ttm_tt *gtt = (void *)ttm;
        unsigned nents;
        int r;

        int write = !(gtt->userflags & AMDGPU_GEM_USERPTR_READONLY);
        enum dma_data_direction direction = write ?
                DMA_BIDIRECTIONAL : DMA_TO_DEVICE;

        /* Allocate an SG array and squash pages into it */
        r = sg_alloc_table_from_pages(ttm->sg, ttm->pages, ttm->num_pages, 0,
                                      ttm->num_pages << PAGE_SHIFT,
                                      GFP_KERNEL);
        if (r)
                goto release_sg;

        /* Map SG to device */
        r = -ENOMEM;
        nents = dma_map_sg(adev->dev, ttm->sg->sgl, ttm->sg->nents, direction);
        if (nents != ttm->sg->nents)
                goto release_sg;

        /* convert SG to linear array of pages and dma addresses */
        drm_prime_sg_to_page_addr_arrays(ttm->sg, ttm->pages,
                                         gtt->ttm.dma_address, ttm->num_pages);

        return 0;

release_sg:
        kfree(ttm->sg);
        return r;
}

/**
 * amdgpu_ttm_tt_unpin_userptr - Unpin and unmap userptr pages
 */
static void amdgpu_ttm_tt_unpin_userptr(struct ttm_tt *ttm)
{
        struct amdgpu_device *adev = amdgpu_ttm_adev(ttm->bdev);
        struct amdgpu_ttm_tt *gtt = (void *)ttm;

        int write = !(gtt->userflags & AMDGPU_GEM_USERPTR_READONLY);
        enum dma_data_direction direction = write ?
                DMA_BIDIRECTIONAL : DMA_TO_DEVICE;

        /* double check that we don't free the table twice */
        if (!ttm->sg->sgl)
                return;

        /* unmap the pages mapped to the device */
        dma_unmap_sg(adev->dev, ttm->sg->sgl, ttm->sg->nents, direction);

        sg_free_table(ttm->sg);

#if IS_ENABLED(CONFIG_DRM_AMDGPU_USERPTR)
        if (gtt->range &&
            ttm->pages[0] == hmm_device_entry_to_page(gtt->range,
                                                      gtt->range->pfns[0]))
                WARN_ONCE(1, "Missing get_user_page_done\n");
#endif
}

int amdgpu_ttm_gart_bind(struct amdgpu_device *adev,
                                struct ttm_buffer_object *tbo,
                                uint64_t flags)
{
        struct amdgpu_bo *abo = ttm_to_amdgpu_bo(tbo);

        struct ttm_tt *ttm = tbo->ttm;
        struct amdgpu_ttm_tt *gtt = (void *)ttm;
        int r;

        if (abo->flags & AMDGPU_GEM_CREATE_MQD_GFX9) {
                uint64_t page_idx = 1;

                r = amdgpu_gart_bind(adev, gtt->offset, page_idx,
                                ttm->pages, gtt->ttm.dma_address, flags);
                if (r)
                        goto gart_bind_fail;

                /* Patch mtype of the second part BO */
                flags &= ~AMDGPU_PTE_MTYPE_VG10_MASK;
                flags |= AMDGPU_PTE_MTYPE_VG10(AMDGPU_MTYPE_NC);

                r = amdgpu_gart_bind(adev,
                                gtt->offset + (page_idx << PAGE_SHIFT),
                                ttm->num_pages - page_idx,
                                &ttm->pages[page_idx],
                                &(gtt->ttm.dma_address[page_idx]), flags);
        } else {
                r = amdgpu_gart_bind(adev, gtt->offset, ttm->num_pages,
                                     ttm->pages, gtt->ttm.dma_address, flags);
        }

gart_bind_fail:
        if (r)
                DRM_ERROR("failed to bind %lu pages at 0x%08llX\n",
                          ttm->num_pages, gtt->offset);

        return r;
}

/**
 * amdgpu_ttm_backend_bind - Bind GTT memory
 *
 * Called by ttm_tt_bind() on behalf of ttm_bo_handle_move_mem().
 * This handles binding GTT memory to the device address space.
 */
static int amdgpu_ttm_backend_bind(struct ttm_tt *ttm,
                                   struct ttm_mem_reg *bo_mem)
{
        struct amdgpu_device *adev = amdgpu_ttm_adev(ttm->bdev);
        struct amdgpu_ttm_tt *gtt = (void*)ttm;
        uint64_t flags;
        int r = 0;

        if (gtt->userptr) {
                r = amdgpu_ttm_tt_pin_userptr(ttm);
                if (r) {
                        DRM_ERROR("failed to pin userptr\n");
                        return r;
                }
        }
        if (!ttm->num_pages) {
                WARN(1, "nothing to bind %lu pages for mreg %p back %p!\n",
                     ttm->num_pages, bo_mem, ttm);
        }

        if (bo_mem->mem_type == AMDGPU_PL_GDS ||
            bo_mem->mem_type == AMDGPU_PL_GWS ||
            bo_mem->mem_type == AMDGPU_PL_OA)
                return -EINVAL;

        if (!amdgpu_gtt_mgr_has_gart_addr(bo_mem)) {
                gtt->offset = AMDGPU_BO_INVALID_OFFSET;
                return 0;
        }

        /* compute PTE flags relevant to this BO memory */
        flags = amdgpu_ttm_tt_pte_flags(adev, ttm, bo_mem);

        /* bind pages into GART page tables */
        gtt->offset = (u64)bo_mem->start << PAGE_SHIFT;
        r = amdgpu_gart_bind(adev, gtt->offset, ttm->num_pages,
                ttm->pages, gtt->ttm.dma_address, flags);

        if (r)
                DRM_ERROR("failed to bind %lu pages at 0x%08llX\n",
                          ttm->num_pages, gtt->offset);
        return r;
}

/**
 * amdgpu_ttm_alloc_gart - Allocate GART memory for buffer object
 */
int amdgpu_ttm_alloc_gart(struct ttm_buffer_object *bo)
{
        struct amdgpu_device *adev = amdgpu_ttm_adev(bo->bdev);
        struct ttm_operation_ctx ctx = { false, false };
        struct amdgpu_ttm_tt *gtt = (void*)bo->ttm;
        struct ttm_mem_reg tmp;
        struct ttm_placement placement;
        struct ttm_place placements;
        uint64_t addr, flags;
        int r;

        if (bo->mem.start != AMDGPU_BO_INVALID_OFFSET)
                return 0;

        addr = amdgpu_gmc_agp_addr(bo);
        if (addr != AMDGPU_BO_INVALID_OFFSET) {
                bo->mem.start = addr >> PAGE_SHIFT;
        } else {

                /* allocate GART space */
                tmp = bo->mem;
                tmp.mm_node = NULL;
                placement.num_placement = 1;
                placement.placement = &placements;
                placement.num_busy_placement = 1;
                placement.busy_placement = &placements;
                placements.fpfn = 0;
                placements.lpfn = adev->gmc.gart_size >> PAGE_SHIFT;
                placements.flags = (bo->mem.placement & ~TTM_PL_MASK_MEM) |
                        TTM_PL_FLAG_TT;

                r = ttm_bo_mem_space(bo, &placement, &tmp, &ctx);
                if (unlikely(r))
                        return r;

                /* compute PTE flags for this buffer object */
                flags = amdgpu_ttm_tt_pte_flags(adev, bo->ttm, &tmp);

                /* Bind pages */
                gtt->offset = (u64)tmp.start << PAGE_SHIFT;
                r = amdgpu_ttm_gart_bind(adev, bo, flags);
                if (unlikely(r)) {
                        ttm_bo_mem_put(bo, &tmp);
                        return r;
                }

                ttm_bo_mem_put(bo, &bo->mem);
                bo->mem = tmp;
        }

        bo->offset = (bo->mem.start << PAGE_SHIFT) +
                bo->bdev->man[bo->mem.mem_type].gpu_offset;

        return 0;
}

/**
 * amdgpu_ttm_recover_gart - Rebind GTT pages
 *
 * Called by amdgpu_gtt_mgr_recover() from amdgpu_device_reset() to
 * rebind GTT pages during a GPU reset.
 */
int amdgpu_ttm_recover_gart(struct ttm_buffer_object *tbo)
{
        struct amdgpu_device *adev = amdgpu_ttm_adev(tbo->bdev);
        uint64_t flags;
        int r;

        if (!tbo->ttm)
                return 0;

        flags = amdgpu_ttm_tt_pte_flags(adev, tbo->ttm, &tbo->mem);
        r = amdgpu_ttm_gart_bind(adev, tbo, flags);

        return r;
}

/**
 * amdgpu_ttm_backend_unbind - Unbind GTT mapped pages
 *
 * Called by ttm_tt_unbind() on behalf of ttm_bo_move_ttm() and
 * ttm_tt_destroy().
 */
static int amdgpu_ttm_backend_unbind(struct ttm_tt *ttm)
{
        struct amdgpu_device *adev = amdgpu_ttm_adev(ttm->bdev);
        struct amdgpu_ttm_tt *gtt = (void *)ttm;
        int r;

        /* if the pages have userptr pinning then clear that first */
        if (gtt->userptr)
                amdgpu_ttm_tt_unpin_userptr(ttm);

        if (gtt->offset == AMDGPU_BO_INVALID_OFFSET)
                return 0;

        /* unbind shouldn't be done for GDS/GWS/OA in ttm_bo_clean_mm */
        r = amdgpu_gart_unbind(adev, gtt->offset, ttm->num_pages);
        if (r)
                DRM_ERROR("failed to unbind %lu pages at 0x%08llX\n",
                          gtt->ttm.ttm.num_pages, gtt->offset);
        return r;
}

static void amdgpu_ttm_backend_destroy(struct ttm_tt *ttm)
{
        struct amdgpu_ttm_tt *gtt = (void *)ttm;

        if (gtt->usertask)
                put_task_struct(gtt->usertask);

        ttm_dma_tt_fini(&gtt->ttm);
        kfree(gtt);
}

static struct ttm_backend_func amdgpu_backend_func = {
        .bind = &amdgpu_ttm_backend_bind,
        .unbind = &amdgpu_ttm_backend_unbind,
        .destroy = &amdgpu_ttm_backend_destroy,
};

/**
 * amdgpu_ttm_tt_create - Create a ttm_tt object for a given BO
 *
 * @bo: The buffer object to create a GTT ttm_tt object around
 *
 * Called by ttm_tt_create().
 */
static struct ttm_tt *amdgpu_ttm_tt_create(struct ttm_buffer_object *bo,
                                           uint32_t page_flags)
{
        struct amdgpu_device *adev;
        struct amdgpu_ttm_tt *gtt;

        adev = amdgpu_ttm_adev(bo->bdev);

        gtt = kzalloc(sizeof(struct amdgpu_ttm_tt), GFP_KERNEL);
        if (gtt == NULL) {
                return NULL;
        }
        gtt->ttm.ttm.func = &amdgpu_backend_func;

        /* allocate space for the uninitialized page entries */
        if (ttm_sg_tt_init(&gtt->ttm, bo, page_flags)) {
                kfree(gtt);
                return NULL;
        }
        return &gtt->ttm.ttm;
}

/**
 * amdgpu_ttm_tt_populate - Map GTT pages visible to the device
 *
 * Map the pages of a ttm_tt object to an address space visible
 * to the underlying device.
 */
static int amdgpu_ttm_tt_populate(struct ttm_tt *ttm,
                        struct ttm_operation_ctx *ctx)
{
        struct amdgpu_device *adev = amdgpu_ttm_adev(ttm->bdev);
        struct amdgpu_ttm_tt *gtt = (void *)ttm;
        bool slave = !!(ttm->page_flags & TTM_PAGE_FLAG_SG);

        /* user pages are bound by amdgpu_ttm_tt_pin_userptr() */
        if (gtt && gtt->userptr) {
                ttm->sg = kzalloc(sizeof(struct sg_table), GFP_KERNEL);
                if (!ttm->sg)
                        return -ENOMEM;

                ttm->page_flags |= TTM_PAGE_FLAG_SG;
                ttm->state = tt_unbound;
                return 0;
        }

        if (slave && ttm->sg) {
                drm_prime_sg_to_page_addr_arrays(ttm->sg, ttm->pages,
                                                 gtt->ttm.dma_address,
                                                 ttm->num_pages);
                ttm->state = tt_unbound;
                return 0;
        }

#ifdef CONFIG_SWIOTLB
        if (adev->need_swiotlb && swiotlb_nr_tbl()) {
                return ttm_dma_populate(&gtt->ttm, adev->dev, ctx);
        }
#endif

        /* fall back to generic helper to populate the page array
         * and map them to the device */
        return ttm_populate_and_map_pages(adev->dev, &gtt->ttm, ctx);
}

/**
 * amdgpu_ttm_tt_unpopulate - unmap GTT pages and unpopulate page arrays
 *
 * Unmaps pages of a ttm_tt object from the device address space and
 * unpopulates the page array backing it.
 */
static void amdgpu_ttm_tt_unpopulate(struct ttm_tt *ttm)
{
        struct amdgpu_device *adev;
        struct amdgpu_ttm_tt *gtt = (void *)ttm;
        bool slave = !!(ttm->page_flags & TTM_PAGE_FLAG_SG);

        if (gtt && gtt->userptr) {
                amdgpu_ttm_tt_set_user_pages(ttm, NULL);
                kfree(ttm->sg);
                ttm->page_flags &= ~TTM_PAGE_FLAG_SG;
                return;
        }

        if (slave)
                return;

        adev = amdgpu_ttm_adev(ttm->bdev);

#ifdef CONFIG_SWIOTLB
        if (adev->need_swiotlb && swiotlb_nr_tbl()) {
                ttm_dma_unpopulate(&gtt->ttm, adev->dev);
                return;
        }
#endif

        /* fall back to generic helper to unmap and unpopulate array */
        ttm_unmap_and_unpopulate_pages(adev->dev, &gtt->ttm);
}

/**
 * amdgpu_ttm_tt_set_userptr - Initialize userptr GTT ttm_tt for the current
 * task
 *
 * @ttm: The ttm_tt object to bind this userptr object to
 * @addr:  The address in the current tasks VM space to use
 * @flags: Requirements of userptr object.
 *
 * Called by amdgpu_gem_userptr_ioctl() to bind userptr pages
 * to current task
 */
int amdgpu_ttm_tt_set_userptr(struct ttm_tt *ttm, uint64_t addr,
                              uint32_t flags)
{
        struct amdgpu_ttm_tt *gtt = (void *)ttm;

        if (gtt == NULL)
                return -EINVAL;

        gtt->userptr = addr;
        gtt->userflags = flags;

        if (gtt->usertask)
                put_task_struct(gtt->usertask);
        gtt->usertask = current->group_leader;
        get_task_struct(gtt->usertask);

        return 0;
}

/**
 * amdgpu_ttm_tt_get_usermm - Return memory manager for ttm_tt object
 */
struct mm_struct *amdgpu_ttm_tt_get_usermm(struct ttm_tt *ttm)
{
        struct amdgpu_ttm_tt *gtt = (void *)ttm;

        if (gtt == NULL)
                return NULL;

        if (gtt->usertask == NULL)
                return NULL;

        return gtt->usertask->mm;
}

/**
 * amdgpu_ttm_tt_affect_userptr - Determine if a ttm_tt object lays inside an
 * address range for the current task.
 *
 */
bool amdgpu_ttm_tt_affect_userptr(struct ttm_tt *ttm, unsigned long start,
                                  unsigned long end)
{
        struct amdgpu_ttm_tt *gtt = (void *)ttm;
        unsigned long size;

        if (gtt == NULL || !gtt->userptr)
                return false;

        /* Return false if no part of the ttm_tt object lies within
         * the range
         */
        size = (unsigned long)gtt->ttm.ttm.num_pages * PAGE_SIZE;
        if (gtt->userptr > end || gtt->userptr + size <= start)
                return false;

        return true;
}

/**
 * amdgpu_ttm_tt_is_userptr - Have the pages backing by userptr?
 */
bool amdgpu_ttm_tt_is_userptr(struct ttm_tt *ttm)
{
        struct amdgpu_ttm_tt *gtt = (void *)ttm;

        if (gtt == NULL || !gtt->userptr)
                return false;

        return true;
}

/**
 * amdgpu_ttm_tt_is_readonly - Is the ttm_tt object read only?
 */
bool amdgpu_ttm_tt_is_readonly(struct ttm_tt *ttm)
{
        struct amdgpu_ttm_tt *gtt = (void *)ttm;

        if (gtt == NULL)
                return false;

        return !!(gtt->userflags & AMDGPU_GEM_USERPTR_READONLY);
}

/**
 * amdgpu_ttm_tt_pde_flags - Compute PDE flags for ttm_tt object
 *
 * @ttm: The ttm_tt object to compute the flags for
 * @mem: The memory registry backing this ttm_tt object
 *
 * Figure out the flags to use for a VM PDE (Page Directory Entry).
 */
uint64_t amdgpu_ttm_tt_pde_flags(struct ttm_tt *ttm, struct ttm_mem_reg *mem)
{
        uint64_t flags = 0;

        if (mem && mem->mem_type != TTM_PL_SYSTEM)
                flags |= AMDGPU_PTE_VALID;

        if (mem && mem->mem_type == TTM_PL_TT) {
                flags |= AMDGPU_PTE_SYSTEM;

                if (ttm->caching_state == tt_cached)
                        flags |= AMDGPU_PTE_SNOOPED;
        }

        return flags;
}

/**
 * amdgpu_ttm_tt_pte_flags - Compute PTE flags for ttm_tt object
 *
 * @ttm: The ttm_tt object to compute the flags for
 * @mem: The memory registry backing this ttm_tt object

 * Figure out the flags to use for a VM PTE (Page Table Entry).
 */
uint64_t amdgpu_ttm_tt_pte_flags(struct amdgpu_device *adev, struct ttm_tt *ttm,
                                 struct ttm_mem_reg *mem)
{
        uint64_t flags = amdgpu_ttm_tt_pde_flags(ttm, mem);

        flags |= adev->gart.gart_pte_flags;
        flags |= AMDGPU_PTE_READABLE;

        if (!amdgpu_ttm_tt_is_readonly(ttm))
                flags |= AMDGPU_PTE_WRITEABLE;

        return flags;
}

/**
 * amdgpu_ttm_bo_eviction_valuable - Check to see if we can evict a buffer
 * object.
 *
 * Return true if eviction is sensible. Called by ttm_mem_evict_first() on
 * behalf of ttm_bo_mem_force_space() which tries to evict buffer objects until
 * it can find space for a new object and by ttm_bo_force_list_clean() which is
 * used to clean out a memory space.
 */
static bool amdgpu_ttm_bo_eviction_valuable(struct ttm_buffer_object *bo,
                                            const struct ttm_place *place)
{
        unsigned long num_pages = bo->mem.num_pages;
        struct drm_mm_node *node = bo->mem.mm_node;
        struct reservation_object_list *flist;
        struct dma_fence *f;
        int i;

        /* Don't evict VM page tables while they are busy, otherwise we can't
         * cleanly handle page faults.
         */
        if (bo->type == ttm_bo_type_kernel &&
            !reservation_object_test_signaled_rcu(bo->resv, true))
                return false;

        /* If bo is a KFD BO, check if the bo belongs to the current process.
         * If true, then return false as any KFD process needs all its BOs to
         * be resident to run successfully
         */
        flist = reservation_object_get_list(bo->resv);
        if (flist) {
                for (i = 0; i < flist->shared_count; ++i) {
                        f = rcu_dereference_protected(flist->shared[i],
                                reservation_object_held(bo->resv));
                        if (amdkfd_fence_check_mm(f, current->mm))
                                return false;
                }
        }

        switch (bo->mem.mem_type) {
        case TTM_PL_TT:
                return true;

        case TTM_PL_VRAM:
                /* Check each drm MM node individually */
                while (num_pages) {
                        if (place->fpfn < (node->start + node->size) &&
                            !(place->lpfn && place->lpfn <= node->start))
                                return true;

                        num_pages -= node->size;
                        ++node;
                }
                return false;

        default:
                break;
        }

        return ttm_bo_eviction_valuable(bo, place);
}

/**
 * amdgpu_ttm_access_memory - Read or Write memory that backs a buffer object.
 *
 * @bo:  The buffer object to read/write
 * @offset:  Offset into buffer object
 * @buf:  Secondary buffer to write/read from
 * @len: Length in bytes of access
 * @write:  true if writing
 *
 * This is used to access VRAM that backs a buffer object via MMIO
 * access for debugging purposes.
 */
static int amdgpu_ttm_access_memory(struct ttm_buffer_object *bo,
                                    unsigned long offset,
                                    void *buf, int len, int write)
{
        struct amdgpu_bo *abo = ttm_to_amdgpu_bo(bo);
        struct amdgpu_device *adev = amdgpu_ttm_adev(abo->tbo.bdev);
        struct drm_mm_node *nodes;
        uint32_t value = 0;
        int ret = 0;
        uint64_t pos;
        unsigned long flags;

        if (bo->mem.mem_type != TTM_PL_VRAM)
                return -EIO;

        nodes = amdgpu_find_mm_node(&abo->tbo.mem, &offset);
        pos = (nodes->start << PAGE_SHIFT) + offset;

        while (len && pos < adev->gmc.mc_vram_size) {
                uint64_t aligned_pos = pos & ~(uint64_t)3;
                uint32_t bytes = 4 - (pos & 3);
                uint32_t shift = (pos & 3) * 8;
                uint32_t mask = 0xffffffff << shift;

                if (len < bytes) {
                        mask &= 0xffffffff >> (bytes - len) * 8;
                        bytes = len;
                }

                spin_lock_irqsave(&adev->mmio_idx_lock, flags);
                WREG32_NO_KIQ(mmMM_INDEX, ((uint32_t)aligned_pos) | 0x80000000);
                WREG32_NO_KIQ(mmMM_INDEX_HI, aligned_pos >> 31);
                if (!write || mask != 0xffffffff)
                        value = RREG32_NO_KIQ(mmMM_DATA);
                if (write) {
                        value &= ~mask;
                        value |= (*(uint32_t *)buf << shift) & mask;
                        WREG32_NO_KIQ(mmMM_DATA, value);
                }
                spin_unlock_irqrestore(&adev->mmio_idx_lock, flags);
                if (!write) {
                        value = (value & mask) >> shift;
                        memcpy(buf, &value, bytes);
                }

                ret += bytes;
                buf = (uint8_t *)buf + bytes;
                pos += bytes;
                len -= bytes;
                if (pos >= (nodes->start + nodes->size) << PAGE_SHIFT) {
                        ++nodes;
                        pos = (nodes->start << PAGE_SHIFT);
                }
        }

        return ret;
}

static struct ttm_bo_driver amdgpu_bo_driver = {
        .ttm_tt_create = &amdgpu_ttm_tt_create,
        .ttm_tt_populate = &amdgpu_ttm_tt_populate,
        .ttm_tt_unpopulate = &amdgpu_ttm_tt_unpopulate,
        .invalidate_caches = &amdgpu_invalidate_caches,
        .init_mem_type = &amdgpu_init_mem_type,
        .eviction_valuable = amdgpu_ttm_bo_eviction_valuable,
        .evict_flags = &amdgpu_evict_flags,
        .move = &amdgpu_bo_move,
        .verify_access = &amdgpu_verify_access,
        .move_notify = &amdgpu_bo_move_notify,
        .fault_reserve_notify = &amdgpu_bo_fault_reserve_notify,
        .io_mem_reserve = &amdgpu_ttm_io_mem_reserve,
        .io_mem_free = &amdgpu_ttm_io_mem_free,
        .io_mem_pfn = amdgpu_ttm_io_mem_pfn,
        .access_memory = &amdgpu_ttm_access_memory,
        .del_from_lru_notify = &amdgpu_vm_del_from_lru_notify
};

/*
 * Firmware Reservation functions
 */
/**
 * amdgpu_ttm_fw_reserve_vram_fini - free fw reserved vram
 *
 * @adev: amdgpu_device pointer
 *
 * free fw reserved vram if it has been reserved.
 */
static void amdgpu_ttm_fw_reserve_vram_fini(struct amdgpu_device *adev)
{
        amdgpu_bo_free_kernel(&adev->fw_vram_usage.reserved_bo,
                NULL, &adev->fw_vram_usage.va);
}

/**
 * amdgpu_ttm_fw_reserve_vram_init - create bo vram reservation from fw
 *
 * @adev: amdgpu_device pointer
 *
 * create bo vram reservation from fw.
 */
static int amdgpu_ttm_fw_reserve_vram_init(struct amdgpu_device *adev)
{
        struct ttm_operation_ctx ctx = { false, false };
        struct amdgpu_bo_param bp;
        int r = 0;
        int i;
        u64 vram_size = adev->gmc.visible_vram_size;
        u64 offset = adev->fw_vram_usage.start_offset;
        u64 size = adev->fw_vram_usage.size;
        struct amdgpu_bo *bo;

        memset(&bp, 0, sizeof(bp));
        bp.size = adev->fw_vram_usage.size;
        bp.byte_align = PAGE_SIZE;
        bp.domain = AMDGPU_GEM_DOMAIN_VRAM;
        bp.flags = AMDGPU_GEM_CREATE_CPU_ACCESS_REQUIRED |
                AMDGPU_GEM_CREATE_VRAM_CONTIGUOUS;
        bp.type = ttm_bo_type_kernel;
        bp.resv = NULL;
        adev->fw_vram_usage.va = NULL;
        adev->fw_vram_usage.reserved_bo = NULL;

        if (adev->fw_vram_usage.size > 0 &&
                adev->fw_vram_usage.size <= vram_size) {

                r = amdgpu_bo_create(adev, &bp,
                                     &adev->fw_vram_usage.reserved_bo);
                if (r)
                        goto error_create;

                r = amdgpu_bo_reserve(adev->fw_vram_usage.reserved_bo, false);
                if (r)
                        goto error_reserve;

                /* remove the original mem node and create a new one at the
                 * request position
                 */
                bo = adev->fw_vram_usage.reserved_bo;
                offset = ALIGN(offset, PAGE_SIZE);
                for (i = 0; i < bo->placement.num_placement; ++i) {
                        bo->placements[i].fpfn = offset >> PAGE_SHIFT;
                        bo->placements[i].lpfn = (offset + size) >> PAGE_SHIFT;
                }

                ttm_bo_mem_put(&bo->tbo, &bo->tbo.mem);
                r = ttm_bo_mem_space(&bo->tbo, &bo->placement,
                                     &bo->tbo.mem, &ctx);
                if (r)
                        goto error_pin;

                r = amdgpu_bo_pin_restricted(adev->fw_vram_usage.reserved_bo,
                        AMDGPU_GEM_DOMAIN_VRAM,
                        adev->fw_vram_usage.start_offset,
                        (adev->fw_vram_usage.start_offset +
                        adev->fw_vram_usage.size));
                if (r)
                        goto error_pin;
                r = amdgpu_bo_kmap(adev->fw_vram_usage.reserved_bo,
                        &adev->fw_vram_usage.va);
                if (r)
                        goto error_kmap;

                amdgpu_bo_unreserve(adev->fw_vram_usage.reserved_bo);
        }
        return r;

error_kmap:
        amdgpu_bo_unpin(adev->fw_vram_usage.reserved_bo);
error_pin:
        amdgpu_bo_unreserve(adev->fw_vram_usage.reserved_bo);
error_reserve:
        amdgpu_bo_unref(&adev->fw_vram_usage.reserved_bo);
error_create:
        adev->fw_vram_usage.va = NULL;
        adev->fw_vram_usage.reserved_bo = NULL;
        return r;
}
/**
 * amdgpu_ttm_init - Init the memory management (ttm) as well as various
 * gtt/vram related fields.
 *
 * This initializes all of the memory space pools that the TTM layer
 * will need such as the GTT space (system memory mapped to the device),
 * VRAM (on-board memory), and on-chip memories (GDS, GWS, OA) which
 * can be mapped per VMID.
 */
int amdgpu_ttm_init(struct amdgpu_device *adev)
{
        uint64_t gtt_size;
        int r;
        u64 vis_vram_limit;

        mutex_init(&adev->mman.gtt_window_lock);

        /* No others user of address space so set it to 0 */
        r = ttm_bo_device_init(&adev->mman.bdev,
                               &amdgpu_bo_driver,
                               adev->ddev->anon_inode->i_mapping,
                               adev->need_dma32);
        if (r) {
                DRM_ERROR("failed initializing buffer object driver(%d).\n", r);
                return r;
        }
        adev->mman.initialized = true;

        /* We opt to avoid OOM on system pages allocations */
        adev->mman.bdev.no_retry = true;

        /* Initialize VRAM pool with all of VRAM divided into pages */
        r = ttm_bo_init_mm(&adev->mman.bdev, TTM_PL_VRAM,
                                adev->gmc.real_vram_size >> PAGE_SHIFT);
        if (r) {
                DRM_ERROR("Failed initializing VRAM heap.\n");
                return r;
        }

        /* Reduce size of CPU-visible VRAM if requested */
        vis_vram_limit = (u64)amdgpu_vis_vram_limit * 1024 * 1024;
        if (amdgpu_vis_vram_limit > 0 &&
            vis_vram_limit <= adev->gmc.visible_vram_size)
                adev->gmc.visible_vram_size = vis_vram_limit;

        /* Change the size here instead of the init above so only lpfn is affected */
        amdgpu_ttm_set_buffer_funcs_status(adev, false);
#ifdef CONFIG_64BIT
        adev->mman.aper_base_kaddr = ioremap_wc(adev->gmc.aper_base,
                                                adev->gmc.visible_vram_size);
#endif

        /*
         *The reserved vram for firmware must be pinned to the specified
         *place on the VRAM, so reserve it early.
         */
        r = amdgpu_ttm_fw_reserve_vram_init(adev);
        if (r) {
                return r;
        }

        /* allocate memory as required for VGA
         * This is used for VGA emulation and pre-OS scanout buffers to
         * avoid display artifacts while transitioning between pre-OS
         * and driver.  */
        r = amdgpu_bo_create_kernel(adev, adev->gmc.stolen_size, PAGE_SIZE,
                                    AMDGPU_GEM_DOMAIN_VRAM,
                                    &adev->stolen_vga_memory,
                                    NULL, NULL);
        if (r)
                return r;
        DRM_INFO("amdgpu: %uM of VRAM memory ready\n",
                 (unsigned) (adev->gmc.real_vram_size / (1024 * 1024)));

        /* Compute GTT size, either bsaed on 3/4th the size of RAM size
         * or whatever the user passed on module init */
        if (amdgpu_gtt_size == -1) {
                struct sysinfo si;

                si_meminfo(&si);
                gtt_size = min(max((AMDGPU_DEFAULT_GTT_SIZE_MB << 20),
                               adev->gmc.mc_vram_size),
                               ((uint64_t)si.totalram * si.mem_unit * 3/4));
        }
        else
                gtt_size = (uint64_t)amdgpu_gtt_size << 20;

        /* Initialize GTT memory pool */
        r = ttm_bo_init_mm(&adev->mman.bdev, TTM_PL_TT, gtt_size >> PAGE_SHIFT);
        if (r) {
                DRM_ERROR("Failed initializing GTT heap.\n");
                return r;
        }
        DRM_INFO("amdgpu: %uM of GTT memory ready.\n",
                 (unsigned)(gtt_size / (1024 * 1024)));

        /* Initialize various on-chip memory pools */
        r = ttm_bo_init_mm(&adev->mman.bdev, AMDGPU_PL_GDS,
                           adev->gds.gds_size);
        if (r) {
                DRM_ERROR("Failed initializing GDS heap.\n");
                return r;
        }

        r = ttm_bo_init_mm(&adev->mman.bdev, AMDGPU_PL_GWS,
                           adev->gds.gws_size);
        if (r) {
                DRM_ERROR("Failed initializing gws heap.\n");
                return r;
        }

        r = ttm_bo_init_mm(&adev->mman.bdev, AMDGPU_PL_OA,
                           adev->gds.oa_size);
        if (r) {
                DRM_ERROR("Failed initializing oa heap.\n");
                return r;
        }

        /* Register debugfs entries for amdgpu_ttm */
        r = amdgpu_ttm_debugfs_init(adev);
        if (r) {
                DRM_ERROR("Failed to init debugfs\n");
                return r;
        }
        return 0;
}

/**
 * amdgpu_ttm_late_init - Handle any late initialization for amdgpu_ttm
 */
void amdgpu_ttm_late_init(struct amdgpu_device *adev)
{
        /* return the VGA stolen memory (if any) back to VRAM */
        amdgpu_bo_free_kernel(&adev->stolen_vga_memory, NULL, NULL);
}

/**
 * amdgpu_ttm_fini - De-initialize the TTM memory pools
 */
void amdgpu_ttm_fini(struct amdgpu_device *adev)
{
        if (!adev->mman.initialized)
                return;

        amdgpu_ttm_debugfs_fini(adev);
        amdgpu_ttm_fw_reserve_vram_fini(adev);
        if (adev->mman.aper_base_kaddr)
                iounmap(adev->mman.aper_base_kaddr);
        adev->mman.aper_base_kaddr = NULL;

        ttm_bo_clean_mm(&adev->mman.bdev, TTM_PL_VRAM);
        ttm_bo_clean_mm(&adev->mman.bdev, TTM_PL_TT);
        ttm_bo_clean_mm(&adev->mman.bdev, AMDGPU_PL_GDS);
        ttm_bo_clean_mm(&adev->mman.bdev, AMDGPU_PL_GWS);
        ttm_bo_clean_mm(&adev->mman.bdev, AMDGPU_PL_OA);
        ttm_bo_device_release(&adev->mman.bdev);
        adev->mman.initialized = false;
        DRM_INFO("amdgpu: ttm finalized\n");
}

/**
 * amdgpu_ttm_set_buffer_funcs_status - enable/disable use of buffer functions
 *
 * @adev: amdgpu_device pointer
 * @enable: true when we can use buffer functions.
 *
 * Enable/disable use of buffer functions during suspend/resume. This should
 * only be called at bootup or when userspace isn't running.
 */
void amdgpu_ttm_set_buffer_funcs_status(struct amdgpu_device *adev, bool enable)
{
        struct ttm_mem_type_manager *man = &adev->mman.bdev.man[TTM_PL_VRAM];
        uint64_t size;
        int r;

        if (!adev->mman.initialized || adev->in_gpu_reset ||
            adev->mman.buffer_funcs_enabled == enable)
                return;

        if (enable) {
                struct amdgpu_ring *ring;
                struct drm_sched_rq *rq;

                ring = adev->mman.buffer_funcs_ring;
                rq = &ring->sched.sched_rq[DRM_SCHED_PRIORITY_KERNEL];
                r = drm_sched_entity_init(&adev->mman.entity, &rq, 1, NULL);
                if (r) {
                        DRM_ERROR("Failed setting up TTM BO move entity (%d)\n",
                                  r);
                        return;
                }
        } else {
                drm_sched_entity_destroy(&adev->mman.entity);
                dma_fence_put(man->move);
                man->move = NULL;
        }

        /* this just adjusts TTM size idea, which sets lpfn to the correct value */
        if (enable)
                size = adev->gmc.real_vram_size;
        else
                size = adev->gmc.visible_vram_size;
        man->size = size >> PAGE_SHIFT;
        adev->mman.buffer_funcs_enabled = enable;
}

int amdgpu_mmap(struct file *filp, struct vm_area_struct *vma)
{
        struct drm_file *file_priv = filp->private_data;
        struct amdgpu_device *adev = file_priv->minor->dev->dev_private;

        if (adev == NULL)
                return -EINVAL;

        return ttm_bo_mmap(filp, vma, &adev->mman.bdev);
}

static int amdgpu_map_buffer(struct ttm_buffer_object *bo,
                             struct ttm_mem_reg *mem, unsigned num_pages,
                             uint64_t offset, unsigned window,
                             struct amdgpu_ring *ring,
                             uint64_t *addr)
{
        struct amdgpu_ttm_tt *gtt = (void *)bo->ttm;
        struct amdgpu_device *adev = ring->adev;
        struct ttm_tt *ttm = bo->ttm;
        struct amdgpu_job *job;
        unsigned num_dw, num_bytes;
        dma_addr_t *dma_address;
        struct dma_fence *fence;
        uint64_t src_addr, dst_addr;
        uint64_t flags;
        int r;

        BUG_ON(adev->mman.buffer_funcs->copy_max_bytes <
               AMDGPU_GTT_MAX_TRANSFER_SIZE * 8);

        *addr = adev->gmc.gart_start;
        *addr += (u64)window * AMDGPU_GTT_MAX_TRANSFER_SIZE *
                AMDGPU_GPU_PAGE_SIZE;

        num_dw = adev->mman.buffer_funcs->copy_num_dw;
        while (num_dw & 0x7)
                num_dw++;

        num_bytes = num_pages * 8;

        r = amdgpu_job_alloc_with_ib(adev, num_dw * 4 + num_bytes, &job);
        if (r)
                return r;

        src_addr = num_dw * 4;
        src_addr += job->ibs[0].gpu_addr;

        dst_addr = amdgpu_bo_gpu_offset(adev->gart.bo);
        dst_addr += window * AMDGPU_GTT_MAX_TRANSFER_SIZE * 8;
        amdgpu_emit_copy_buffer(adev, &job->ibs[0], src_addr,
                                dst_addr, num_bytes);

        amdgpu_ring_pad_ib(ring, &job->ibs[0]);
        WARN_ON(job->ibs[0].length_dw > num_dw);

        dma_address = &gtt->ttm.dma_address[offset >> PAGE_SHIFT];
        flags = amdgpu_ttm_tt_pte_flags(adev, ttm, mem);
        r = amdgpu_gart_map(adev, 0, num_pages, dma_address, flags,
                            &job->ibs[0].ptr[num_dw]);
        if (r)
                goto error_free;

        r = amdgpu_job_submit(job, &adev->mman.entity,
                              AMDGPU_FENCE_OWNER_UNDEFINED, &fence);
        if (r)
                goto error_free;

        dma_fence_put(fence);

        return r;

error_free:
        amdgpu_job_free(job);
        return r;
}

int amdgpu_copy_buffer(struct amdgpu_ring *ring, uint64_t src_offset,
                       uint64_t dst_offset, uint32_t byte_count,
                       struct reservation_object *resv,
                       struct dma_fence **fence, bool direct_submit,
                       bool vm_needs_flush)
{
        struct amdgpu_device *adev = ring->adev;
        struct amdgpu_job *job;

        uint32_t max_bytes;
        unsigned num_loops, num_dw;
        unsigned i;
        int r;

        if (direct_submit && !ring->sched.ready) {
                DRM_ERROR("Trying to move memory with ring turned off.\n");
                return -EINVAL;
        }

        max_bytes = adev->mman.buffer_funcs->copy_max_bytes;
        num_loops = DIV_ROUND_UP(byte_count, max_bytes);
        num_dw = num_loops * adev->mman.buffer_funcs->copy_num_dw;

        /* for IB padding */
        while (num_dw & 0x7)
                num_dw++;

        r = amdgpu_job_alloc_with_ib(adev, num_dw * 4, &job);
        if (r)
                return r;

        if (vm_needs_flush) {
                job->vm_pd_addr = amdgpu_gmc_pd_addr(adev->gart.bo);
                job->vm_needs_flush = true;
        }
        if (resv) {
                r = amdgpu_sync_resv(adev, &job->sync, resv,
                                     AMDGPU_FENCE_OWNER_UNDEFINED,
                                     false);
                if (r) {
                        DRM_ERROR("sync failed (%d).\n", r);
                        goto error_free;
                }
        }

        for (i = 0; i < num_loops; i++) {
                uint32_t cur_size_in_bytes = min(byte_count, max_bytes);

                amdgpu_emit_copy_buffer(adev, &job->ibs[0], src_offset,
                                        dst_offset, cur_size_in_bytes);

                src_offset += cur_size_in_bytes;
                dst_offset += cur_size_in_bytes;
                byte_count -= cur_size_in_bytes;
        }

        amdgpu_ring_pad_ib(ring, &job->ibs[0]);
        WARN_ON(job->ibs[0].length_dw > num_dw);
        if (direct_submit)
                r = amdgpu_job_submit_direct(job, ring, fence);
        else
                r = amdgpu_job_submit(job, &adev->mman.entity,
                                      AMDGPU_FENCE_OWNER_UNDEFINED, fence);
        if (r)
                goto error_free;

        return r;

error_free:
        amdgpu_job_free(job);
        DRM_ERROR("Error scheduling IBs (%d)\n", r);
        return r;
}

int amdgpu_fill_buffer(struct amdgpu_bo *bo,
                       uint32_t src_data,
                       struct reservation_object *resv,
                       struct dma_fence **fence)
{
        struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
        uint32_t max_bytes = adev->mman.buffer_funcs->fill_max_bytes;
        struct amdgpu_ring *ring = adev->mman.buffer_funcs_ring;

        struct drm_mm_node *mm_node;
        unsigned long num_pages;
        unsigned int num_loops, num_dw;

        struct amdgpu_job *job;
        int r;

        if (!adev->mman.buffer_funcs_enabled) {
                DRM_ERROR("Trying to clear memory with ring turned off.\n");
                return -EINVAL;
        }

        if (bo->tbo.mem.mem_type == TTM_PL_TT) {
                r = amdgpu_ttm_alloc_gart(&bo->tbo);
                if (r)
                        return r;
        }

        num_pages = bo->tbo.num_pages;
        mm_node = bo->tbo.mem.mm_node;
        num_loops = 0;
        while (num_pages) {
                uint64_t byte_count = mm_node->size << PAGE_SHIFT;

                num_loops += DIV_ROUND_UP_ULL(byte_count, max_bytes);
                num_pages -= mm_node->size;
                ++mm_node;
        }
        num_dw = num_loops * adev->mman.buffer_funcs->fill_num_dw;

        /* for IB padding */
        num_dw += 64;

        r = amdgpu_job_alloc_with_ib(adev, num_dw * 4, &job);
        if (r)
                return r;

        if (resv) {
                r = amdgpu_sync_resv(adev, &job->sync, resv,
                                     AMDGPU_FENCE_OWNER_UNDEFINED, false);
                if (r) {
                        DRM_ERROR("sync failed (%d).\n", r);
                        goto error_free;
                }
        }

        num_pages = bo->tbo.num_pages;
        mm_node = bo->tbo.mem.mm_node;

        while (num_pages) {
                uint64_t byte_count = mm_node->size << PAGE_SHIFT;
                uint64_t dst_addr;

                dst_addr = amdgpu_mm_node_addr(&bo->tbo, mm_node, &bo->tbo.mem);
                while (byte_count) {
                        uint32_t cur_size_in_bytes = min_t(uint64_t, byte_count,
                                                           max_bytes);

                        amdgpu_emit_fill_buffer(adev, &job->ibs[0], src_data,
                                                dst_addr, cur_size_in_bytes);

                        dst_addr += cur_size_in_bytes;
                        byte_count -= cur_size_in_bytes;
                }

                num_pages -= mm_node->size;
                ++mm_node;
        }

        amdgpu_ring_pad_ib(ring, &job->ibs[0]);
        WARN_ON(job->ibs[0].length_dw > num_dw);
        r = amdgpu_job_submit(job, &adev->mman.entity,
                              AMDGPU_FENCE_OWNER_UNDEFINED, fence);
        if (r)
                goto error_free;

        return 0;

error_free:
        amdgpu_job_free(job);
        return r;
}

#if defined(CONFIG_DEBUG_FS)

static int amdgpu_mm_dump_table(struct seq_file *m, void *data)
{
        struct drm_info_node *node = (struct drm_info_node *)m->private;
        unsigned ttm_pl = (uintptr_t)node->info_ent->data;
        struct drm_device *dev = node->minor->dev;
        struct amdgpu_device *adev = dev->dev_private;
        struct ttm_mem_type_manager *man = &adev->mman.bdev.man[ttm_pl];
        struct drm_printer p = drm_seq_file_printer(m);

        man->func->debug(man, &p);
        return 0;
}

static const struct drm_info_list amdgpu_ttm_debugfs_list[] = {
        {"amdgpu_vram_mm", amdgpu_mm_dump_table, 0, (void *)TTM_PL_VRAM},
        {"amdgpu_gtt_mm", amdgpu_mm_dump_table, 0, (void *)TTM_PL_TT},
        {"amdgpu_gds_mm", amdgpu_mm_dump_table, 0, (void *)AMDGPU_PL_GDS},
        {"amdgpu_gws_mm", amdgpu_mm_dump_table, 0, (void *)AMDGPU_PL_GWS},
        {"amdgpu_oa_mm", amdgpu_mm_dump_table, 0, (void *)AMDGPU_PL_OA},
        {"ttm_page_pool", ttm_page_alloc_debugfs, 0, NULL},
#ifdef CONFIG_SWIOTLB
        {"ttm_dma_page_pool", ttm_dma_page_alloc_debugfs, 0, NULL}
#endif
};

/**
 * amdgpu_ttm_vram_read - Linear read access to VRAM
 *
 * Accesses VRAM via MMIO for debugging purposes.
 */
static ssize_t amdgpu_ttm_vram_read(struct file *f, char __user *buf,
                                    size_t size, loff_t *pos)
{
        struct amdgpu_device *adev = file_inode(f)->i_private;
        ssize_t result = 0;
        int r;

        if (size & 0x3 || *pos & 0x3)
                return -EINVAL;

        if (*pos >= adev->gmc.mc_vram_size)
                return -ENXIO;

        while (size) {
                unsigned long flags;
                uint32_t value;

                if (*pos >= adev->gmc.mc_vram_size)
                        return result;

                spin_lock_irqsave(&adev->mmio_idx_lock, flags);
                WREG32_NO_KIQ(mmMM_INDEX, ((uint32_t)*pos) | 0x80000000);
                WREG32_NO_KIQ(mmMM_INDEX_HI, *pos >> 31);
                value = RREG32_NO_KIQ(mmMM_DATA);
                spin_unlock_irqrestore(&adev->mmio_idx_lock, flags);

                r = put_user(value, (uint32_t *)buf);
                if (r)
                        return r;

                result += 4;
                buf += 4;
                *pos += 4;
                size -= 4;
        }

        return result;
}

/**
 * amdgpu_ttm_vram_write - Linear write access to VRAM
 *
 * Accesses VRAM via MMIO for debugging purposes.
 */
static ssize_t amdgpu_ttm_vram_write(struct file *f, const char __user *buf,
                                    size_t size, loff_t *pos)
{
        struct amdgpu_device *adev = file_inode(f)->i_private;
        ssize_t result = 0;
        int r;

        if (size & 0x3 || *pos & 0x3)
                return -EINVAL;

        if (*pos >= adev->gmc.mc_vram_size)
                return -ENXIO;

        while (size) {
                unsigned long flags;
                uint32_t value;

                if (*pos >= adev->gmc.mc_vram_size)
                        return result;

                r = get_user(value, (uint32_t *)buf);
                if (r)
                        return r;

                spin_lock_irqsave(&adev->mmio_idx_lock, flags);
                WREG32_NO_KIQ(mmMM_INDEX, ((uint32_t)*pos) | 0x80000000);
                WREG32_NO_KIQ(mmMM_INDEX_HI, *pos >> 31);
                WREG32_NO_KIQ(mmMM_DATA, value);
                spin_unlock_irqrestore(&adev->mmio_idx_lock, flags);

                result += 4;
                buf += 4;
                *pos += 4;
                size -= 4;
        }

        return result;
}

static const struct file_operations amdgpu_ttm_vram_fops = {
        .owner = THIS_MODULE,
        .read = amdgpu_ttm_vram_read,
        .write = amdgpu_ttm_vram_write,
        .llseek = default_llseek,
};

#ifdef CONFIG_DRM_AMDGPU_GART_DEBUGFS

/**
 * amdgpu_ttm_gtt_read - Linear read access to GTT memory
 */
static ssize_t amdgpu_ttm_gtt_read(struct file *f, char __user *buf,
                                   size_t size, loff_t *pos)
{
        struct amdgpu_device *adev = file_inode(f)->i_private;
        ssize_t result = 0;
        int r;

        while (size) {
                loff_t p = *pos / PAGE_SIZE;
                unsigned off = *pos & ~PAGE_MASK;
                size_t cur_size = min_t(size_t, size, PAGE_SIZE - off);
                struct page *page;
                void *ptr;

                if (p >= adev->gart.num_cpu_pages)
                        return result;

                page = adev->gart.pages[p];
                if (page) {
                        ptr = kmap(page);
                        ptr += off;

                        r = copy_to_user(buf, ptr, cur_size);
                        kunmap(adev->gart.pages[p]);
                } else
                        r = clear_user(buf, cur_size);

                if (r)
                        return -EFAULT;

                result += cur_size;
                buf += cur_size;
                *pos += cur_size;
                size -= cur_size;
        }

        return result;
}

static const struct file_operations amdgpu_ttm_gtt_fops = {
        .owner = THIS_MODULE,
        .read = amdgpu_ttm_gtt_read,
        .llseek = default_llseek
};

#endif

/**
 * amdgpu_iomem_read - Virtual read access to GPU mapped memory
 *
 * This function is used to read memory that has been mapped to the
 * GPU and the known addresses are not physical addresses but instead
 * bus addresses (e.g., what you'd put in an IB or ring buffer).
 */
static ssize_t amdgpu_iomem_read(struct file *f, char __user *buf,
                                 size_t size, loff_t *pos)
{
        struct amdgpu_device *adev = file_inode(f)->i_private;
        struct iommu_domain *dom;
        ssize_t result = 0;
        int r;

        /* retrieve the IOMMU domain if any for this device */
        dom = iommu_get_domain_for_dev(adev->dev);

        while (size) {
                phys_addr_t addr = *pos & PAGE_MASK;
                loff_t off = *pos & ~PAGE_MASK;
                size_t bytes = PAGE_SIZE - off;
                unsigned long pfn;
                struct page *p;
                void *ptr;

                bytes = bytes < size ? bytes : size;

                /* Translate the bus address to a physical address.  If
                 * the domain is NULL it means there is no IOMMU active
                 * and the address translation is the identity
                 */
                addr = dom ? iommu_iova_to_phys(dom, addr) : addr;

                pfn = addr >> PAGE_SHIFT;
                if (!pfn_valid(pfn))
                        return -EPERM;

                p = pfn_to_page(pfn);
                if (p->mapping != adev->mman.bdev.dev_mapping)
                        return -EPERM;

                ptr = kmap(p);
                r = copy_to_user(buf, ptr + off, bytes);
                kunmap(p);
                if (r)
                        return -EFAULT;

                size -= bytes;
                *pos += bytes;
                result += bytes;
        }

        return result;
}

/**
 * amdgpu_iomem_write - Virtual write access to GPU mapped memory
 *
 * This function is used to write memory that has been mapped to the
 * GPU and the known addresses are not physical addresses but instead
 * bus addresses (e.g., what you'd put in an IB or ring buffer).
 */
static ssize_t amdgpu_iomem_write(struct file *f, const char __user *buf,
                                 size_t size, loff_t *pos)
{
        struct amdgpu_device *adev = file_inode(f)->i_private;
        struct iommu_domain *dom;
        ssize_t result = 0;
        int r;

        dom = iommu_get_domain_for_dev(adev->dev);

        while (size) {
                phys_addr_t addr = *pos & PAGE_MASK;
                loff_t off = *pos & ~PAGE_MASK;
                size_t bytes = PAGE_SIZE - off;
                unsigned long pfn;
                struct page *p;
                void *ptr;

                bytes = bytes < size ? bytes : size;

                addr = dom ? iommu_iova_to_phys(dom, addr) : addr;

                pfn = addr >> PAGE_SHIFT;
                if (!pfn_valid(pfn))
                        return -EPERM;

                p = pfn_to_page(pfn);
                if (p->mapping != adev->mman.bdev.dev_mapping)
                        return -EPERM;

                ptr = kmap(p);
                r = copy_from_user(ptr + off, buf, bytes);
                kunmap(p);
                if (r)
                        return -EFAULT;

                size -= bytes;
                *pos += bytes;
                result += bytes;
        }

        return result;
}

static const struct file_operations amdgpu_ttm_iomem_fops = {
        .owner = THIS_MODULE,
        .read = amdgpu_iomem_read,
        .write = amdgpu_iomem_write,
        .llseek = default_llseek
};

static const struct {
        char *name;
        const struct file_operations *fops;
        int domain;
} ttm_debugfs_entries[] = {
        { "amdgpu_vram", &amdgpu_ttm_vram_fops, TTM_PL_VRAM },
#ifdef CONFIG_DRM_AMDGPU_GART_DEBUGFS
        { "amdgpu_gtt", &amdgpu_ttm_gtt_fops, TTM_PL_TT },
#endif
        { "amdgpu_iomem", &amdgpu_ttm_iomem_fops, TTM_PL_SYSTEM },
};

#endif

static int amdgpu_ttm_debugfs_init(struct amdgpu_device *adev)
{
#if defined(CONFIG_DEBUG_FS)
        unsigned count;

        struct drm_minor *minor = adev->ddev->primary;
        struct dentry *ent, *root = minor->debugfs_root;

        for (count = 0; count < ARRAY_SIZE(ttm_debugfs_entries); count++) {
                ent = debugfs_create_file(
                                ttm_debugfs_entries[count].name,
                                S_IFREG | S_IRUGO, root,
                                adev,
                                ttm_debugfs_entries[count].fops);
                if (IS_ERR(ent))
                        return PTR_ERR(ent);
                if (ttm_debugfs_entries[count].domain == TTM_PL_VRAM)
                        i_size_write(ent->d_inode, adev->gmc.mc_vram_size);
                else if (ttm_debugfs_entries[count].domain == TTM_PL_TT)
                        i_size_write(ent->d_inode, adev->gmc.gart_size);
                adev->mman.debugfs_entries[count] = ent;
        }

        count = ARRAY_SIZE(amdgpu_ttm_debugfs_list);

#ifdef CONFIG_SWIOTLB
        if (!(adev->need_swiotlb && swiotlb_nr_tbl()))
                --count;
#endif

        return amdgpu_debugfs_add_files(adev, amdgpu_ttm_debugfs_list, count);
#else
        return 0;
#endif
}

static void amdgpu_ttm_debugfs_fini(struct amdgpu_device *adev)
{
#if defined(CONFIG_DEBUG_FS)
        unsigned i;

        for (i = 0; i < ARRAY_SIZE(ttm_debugfs_entries); i++)
                debugfs_remove(adev->mman.debugfs_entries[i]);
#endif
}