/*
 * Copyright 2008 Advanced Micro Devices, Inc.
 * Copyright 2008 Red Hat Inc.
 * Copyright 2009 Jerome Glisse.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 *
 * Authors: Dave Airlie
 *          Alex Deucher
 *          Jerome Glisse
 */
#include <drm/drmP.h>
#include <drm/amdgpu_drm.h>
#include "amdgpu.h"
#include "amdgpu_trace.h"

/*
 * GPUVM
 * GPUVM is similar to the legacy gart on older asics, however
 * rather than there being a single global gart table
 * for the entire GPU, there are multiple VM page tables active
 * at any given time.  The VM page tables can contain a mix
 * vram pages and system memory pages and system memory pages
 * can be mapped as snooped (cached system pages) or unsnooped
 * (uncached system pages).
 * Each VM has an ID associated with it and there is a page table
 * associated with each VMID.  When execting a command buffer,
 * the kernel tells the the ring what VMID to use for that command
 * buffer.  VMIDs are allocated dynamically as commands are submitted.
 * The userspace drivers maintain their own address space and the kernel
 * sets up their pages tables accordingly when they submit their
 * command buffers and a VMID is assigned.
 * Cayman/Trinity support up to 8 active VMs at any given time;
 * SI supports 16.
 */

/**
 * amdgpu_vm_num_pde - return the number of page directory entries
 *
 * @adev: amdgpu_device pointer
 *
 * Calculate the number of page directory entries (cayman+).
 */
static unsigned amdgpu_vm_num_pdes(struct amdgpu_device *adev)
{
        return adev->vm_manager.max_pfn >> amdgpu_vm_block_size;
}

/**
 * amdgpu_vm_directory_size - returns the size of the page directory in bytes
 *
 * @adev: amdgpu_device pointer
 *
 * Calculate the size of the page directory in bytes (cayman+).
 */
static unsigned amdgpu_vm_directory_size(struct amdgpu_device *adev)
{
        return AMDGPU_GPU_PAGE_ALIGN(amdgpu_vm_num_pdes(adev) * 8);
}

/**
 * amdgpu_vm_get_pd_bo - add the VM PD to a validation list
 *
 * @vm: vm providing the BOs
 * @validated: head of validation list
 * @entry: entry to add
 *
 * Add the page directory to the list of BOs to
 * validate for command submission.
 */
void amdgpu_vm_get_pd_bo(struct amdgpu_vm *vm,
                         struct list_head *validated,
                         struct amdgpu_bo_list_entry *entry)
{
        entry->robj = vm->page_directory;
        entry->prefered_domains = AMDGPU_GEM_DOMAIN_VRAM;
        entry->allowed_domains = AMDGPU_GEM_DOMAIN_VRAM;
        entry->priority = 0;
        entry->tv.bo = &vm->page_directory->tbo;
        entry->tv.shared = true;
        list_add(&entry->tv.head, validated);
}

/**
 * amdgpu_vm_get_bos - add the vm BOs to a duplicates list
 *
 * @vm: vm providing the BOs
 * @duplicates: head of duplicates list
 *
 * Add the page directory to the BO duplicates list
 * for command submission.
 */
void amdgpu_vm_get_pt_bos(struct amdgpu_vm *vm, struct list_head *duplicates)
{
        unsigned i;

        /* add the vm page table to the list */
        for (i = 0; i <= vm->max_pde_used; ++i) {
                struct amdgpu_bo_list_entry *entry = &vm->page_tables[i].entry;

                if (!entry->robj)
                        continue;

                list_add(&entry->tv.head, duplicates);
        }

}

/**
 * amdgpu_vm_move_pt_bos_in_lru - move the PT BOs to the LRU tail
 *
 * @adev: amdgpu device instance
 * @vm: vm providing the BOs
 *
 * Move the PT BOs to the tail of the LRU.
 */
void amdgpu_vm_move_pt_bos_in_lru(struct amdgpu_device *adev,
                                  struct amdgpu_vm *vm)
{
        struct ttm_bo_global *glob = adev->mman.bdev.glob;
        unsigned i;

        spin_lock(&glob->lru_lock);
        for (i = 0; i <= vm->max_pde_used; ++i) {
                struct amdgpu_bo_list_entry *entry = &vm->page_tables[i].entry;

                if (!entry->robj)
                        continue;

                ttm_bo_move_to_lru_tail(&entry->robj->tbo);
        }
        spin_unlock(&glob->lru_lock);
}

/**
 * amdgpu_vm_grab_id - allocate the next free VMID
 *
 * @vm: vm to allocate id for
 * @ring: ring we want to submit job to
 * @sync: sync object where we add dependencies
 *
 * Allocate an id for the vm, adding fences to the sync obj as necessary.
 *
 * Global mutex must be locked!
 */
int amdgpu_vm_grab_id(struct amdgpu_vm *vm, struct amdgpu_ring *ring,
                      struct amdgpu_sync *sync)
{
        struct fence *best[AMDGPU_MAX_RINGS] = {};
        struct amdgpu_vm_id *vm_id = &vm->ids[ring->idx];
        struct amdgpu_device *adev = ring->adev;

        unsigned choices[2] = {};
        unsigned i;

        /* check if the id is still valid */
        if (vm_id->id) {
                unsigned id = vm_id->id;
                long owner;

                owner = atomic_long_read(&adev->vm_manager.ids[id].owner);
                if (owner == (long)vm) {
                        trace_amdgpu_vm_grab_id(vm_id->id, ring->idx);
                        return 0;
                }
        }

        /* we definately need to flush */
        vm_id->pd_gpu_addr = ~0ll;

        /* skip over VMID 0, since it is the system VM */
        for (i = 1; i < adev->vm_manager.nvm; ++i) {
                struct fence *fence = adev->vm_manager.ids[i].active;
                struct amdgpu_ring *fring;

                if (fence == NULL) {
                        /* found a free one */
                        vm_id->id = i;
                        trace_amdgpu_vm_grab_id(i, ring->idx);
                        return 0;
                }

                fring = amdgpu_ring_from_fence(fence);
                if (best[fring->idx] == NULL ||
                    fence_is_later(best[fring->idx], fence)) {
                        best[fring->idx] = fence;
                        choices[fring == ring ? 0 : 1] = i;
                }
        }

        for (i = 0; i < 2; ++i) {
                if (choices[i]) {
                        struct fence *fence;

                        fence  = adev->vm_manager.ids[choices[i]].active;
                        vm_id->id = choices[i];

                        trace_amdgpu_vm_grab_id(choices[i], ring->idx);
                        return amdgpu_sync_fence(ring->adev, sync, fence);
                }
        }

        /* should never happen */
        BUG();
        return -EINVAL;
}

/**
 * amdgpu_vm_flush - hardware flush the vm
 *
 * @ring: ring to use for flush
 * @vm: vm we want to flush
 * @updates: last vm update that we waited for
 *
 * Flush the vm (cayman+).
 *
 * Global and local mutex must be locked!
 */
void amdgpu_vm_flush(struct amdgpu_ring *ring,
                     struct amdgpu_vm *vm,
                     struct fence *updates)
{
        uint64_t pd_addr = amdgpu_bo_gpu_offset(vm->page_directory);
        struct amdgpu_vm_id *vm_id = &vm->ids[ring->idx];
        struct fence *flushed_updates = vm_id->flushed_updates;
        bool is_later;

        if (!flushed_updates)
                is_later = true;
        else if (!updates)
                is_later = false;
        else
                is_later = fence_is_later(updates, flushed_updates);

        if (pd_addr != vm_id->pd_gpu_addr || is_later) {
                trace_amdgpu_vm_flush(pd_addr, ring->idx, vm_id->id);
                if (is_later) {
                        vm_id->flushed_updates = fence_get(updates);
                        fence_put(flushed_updates);
                }
                vm_id->pd_gpu_addr = pd_addr;
                amdgpu_ring_emit_vm_flush(ring, vm_id->id, vm_id->pd_gpu_addr);
        }
}

/**
 * amdgpu_vm_fence - remember fence for vm
 *
 * @adev: amdgpu_device pointer
 * @vm: vm we want to fence
 * @fence: fence to remember
 *
 * Fence the vm (cayman+).
 * Set the fence used to protect page table and id.
 *
 * Global and local mutex must be locked!
 */
void amdgpu_vm_fence(struct amdgpu_device *adev,
                     struct amdgpu_vm *vm,
                     struct fence *fence)
{
        struct amdgpu_ring *ring = amdgpu_ring_from_fence(fence);
        unsigned vm_id = vm->ids[ring->idx].id;

        fence_put(adev->vm_manager.ids[vm_id].active);
        adev->vm_manager.ids[vm_id].active = fence_get(fence);
        atomic_long_set(&adev->vm_manager.ids[vm_id].owner, (long)vm);
}

/**
 * amdgpu_vm_bo_find - find the bo_va for a specific vm & bo
 *
 * @vm: requested vm
 * @bo: requested buffer object
 *
 * Find @bo inside the requested vm (cayman+).
 * Search inside the @bos vm list for the requested vm
 * Returns the found bo_va or NULL if none is found
 *
 * Object has to be reserved!
 */
struct amdgpu_bo_va *amdgpu_vm_bo_find(struct amdgpu_vm *vm,
                                       struct amdgpu_bo *bo)
{
        struct amdgpu_bo_va *bo_va;

        list_for_each_entry(bo_va, &bo->va, bo_list) {
                if (bo_va->vm == vm) {
                        return bo_va;
                }
        }
        return NULL;
}

/**
 * amdgpu_vm_update_pages - helper to call the right asic function
 *
 * @adev: amdgpu_device pointer
 * @ib: indirect buffer to fill with commands
 * @pe: addr of the page entry
 * @addr: dst addr to write into pe
 * @count: number of page entries to update
 * @incr: increase next addr by incr bytes
 * @flags: hw access flags
 * @gtt_flags: GTT hw access flags
 *
 * Traces the parameters and calls the right asic functions
 * to setup the page table using the DMA.
 */
static void amdgpu_vm_update_pages(struct amdgpu_device *adev,
                                   struct amdgpu_ib *ib,
                                   uint64_t pe, uint64_t addr,
                                   unsigned count, uint32_t incr,
                                   uint32_t flags, uint32_t gtt_flags)
{
        trace_amdgpu_vm_set_page(pe, addr, count, incr, flags);

        if ((flags & AMDGPU_PTE_SYSTEM) && (flags == gtt_flags)) {
                uint64_t src = adev->gart.table_addr + (addr >> 12) * 8;
                amdgpu_vm_copy_pte(adev, ib, pe, src, count);

        } else if ((flags & AMDGPU_PTE_SYSTEM) || (count < 3)) {
                amdgpu_vm_write_pte(adev, ib, pe, addr,
                                      count, incr, flags);

        } else {
                amdgpu_vm_set_pte_pde(adev, ib, pe, addr,
                                      count, incr, flags);
        }
}

int amdgpu_vm_free_job(struct amdgpu_job *job)
{
        int i;
        for (i = 0; i < job->num_ibs; i++)
                amdgpu_ib_free(job->adev, &job->ibs[i]);
        kfree(job->ibs);
        return 0;
}

/**
 * amdgpu_vm_clear_bo - initially clear the page dir/table
 *
 * @adev: amdgpu_device pointer
 * @bo: bo to clear
 *
 * need to reserve bo first before calling it.
 */
static int amdgpu_vm_clear_bo(struct amdgpu_device *adev,
                              struct amdgpu_bo *bo)
{
        struct amdgpu_ring *ring = adev->vm_manager.vm_pte_funcs_ring;
        struct fence *fence = NULL;
        struct amdgpu_ib *ib;
        unsigned entries;
        uint64_t addr;
        int r;

        r = reservation_object_reserve_shared(bo->tbo.resv);
        if (r)
                return r;

        r = ttm_bo_validate(&bo->tbo, &bo->placement, true, false);
        if (r)
                goto error;

        addr = amdgpu_bo_gpu_offset(bo);
        entries = amdgpu_bo_size(bo) / 8;

        ib = kzalloc(sizeof(struct amdgpu_ib), GFP_KERNEL);
        if (!ib)
                goto error;

        r = amdgpu_ib_get(ring, NULL, entries * 2 + 64, ib);
        if (r)
                goto error_free;

        ib->length_dw = 0;

        amdgpu_vm_update_pages(adev, ib, addr, 0, entries, 0, 0, 0);
        amdgpu_vm_pad_ib(adev, ib);
        WARN_ON(ib->length_dw > 64);
        r = amdgpu_sched_ib_submit_kernel_helper(adev, ring, ib, 1,
                                                 &amdgpu_vm_free_job,
                                                 AMDGPU_FENCE_OWNER_VM,
                                                 &fence);
        if (!r)
                amdgpu_bo_fence(bo, fence, true);
        fence_put(fence);
        if (amdgpu_enable_scheduler)
                return 0;

error_free:
        amdgpu_ib_free(adev, ib);
        kfree(ib);

error:
        return r;
}

/**
 * amdgpu_vm_map_gart - get the physical address of a gart page
 *
 * @adev: amdgpu_device pointer
 * @addr: the unmapped addr
 *
 * Look up the physical address of the page that the pte resolves
 * to (cayman+).
 * Returns the physical address of the page.
 */
uint64_t amdgpu_vm_map_gart(struct amdgpu_device *adev, uint64_t addr)
{
        uint64_t result;

        /* page table offset */
        result = adev->gart.pages_addr[addr >> PAGE_SHIFT];

        /* in case cpu page size != gpu page size*/
        result |= addr & (~PAGE_MASK);

        return result;
}

/**
 * amdgpu_vm_update_pdes - make sure that page directory is valid
 *
 * @adev: amdgpu_device pointer
 * @vm: requested vm
 * @start: start of GPU address range
 * @end: end of GPU address range
 *
 * Allocates new page tables if necessary
 * and updates the page directory (cayman+).
 * Returns 0 for success, error for failure.
 *
 * Global and local mutex must be locked!
 */
int amdgpu_vm_update_page_directory(struct amdgpu_device *adev,
                                    struct amdgpu_vm *vm)
{
        struct amdgpu_ring *ring = adev->vm_manager.vm_pte_funcs_ring;
        struct amdgpu_bo *pd = vm->page_directory;
        uint64_t pd_addr = amdgpu_bo_gpu_offset(pd);
        uint32_t incr = AMDGPU_VM_PTE_COUNT * 8;
        uint64_t last_pde = ~0, last_pt = ~0;
        unsigned count = 0, pt_idx, ndw;
        struct amdgpu_ib *ib;
        struct fence *fence = NULL;

        int r;

        /* padding, etc. */
        ndw = 64;

        /* assume the worst case */
        ndw += vm->max_pde_used * 6;

        /* update too big for an IB */
        if (ndw > 0xfffff)
                return -ENOMEM;

        ib = kzalloc(sizeof(struct amdgpu_ib), GFP_KERNEL);
        if (!ib)
                return -ENOMEM;

        r = amdgpu_ib_get(ring, NULL, ndw * 4, ib);
        if (r) {
                kfree(ib);
                return r;
        }
        ib->length_dw = 0;

        /* walk over the address space and update the page directory */
        for (pt_idx = 0; pt_idx <= vm->max_pde_used; ++pt_idx) {
                struct amdgpu_bo *bo = vm->page_tables[pt_idx].entry.robj;
                uint64_t pde, pt;

                if (bo == NULL)
                        continue;

                pt = amdgpu_bo_gpu_offset(bo);
                if (vm->page_tables[pt_idx].addr == pt)
                        continue;
                vm->page_tables[pt_idx].addr = pt;

                pde = pd_addr + pt_idx * 8;
                if (((last_pde + 8 * count) != pde) ||
                    ((last_pt + incr * count) != pt)) {

                        if (count) {
                                amdgpu_vm_update_pages(adev, ib, last_pde,
                                                       last_pt, count, incr,
                                                       AMDGPU_PTE_VALID, 0);
                        }

                        count = 1;
                        last_pde = pde;
                        last_pt = pt;
                } else {
                        ++count;
                }
        }

        if (count)
                amdgpu_vm_update_pages(adev, ib, last_pde, last_pt, count,
                                       incr, AMDGPU_PTE_VALID, 0);

        if (ib->length_dw != 0) {
                amdgpu_vm_pad_ib(adev, ib);
                amdgpu_sync_resv(adev, &ib->sync, pd->tbo.resv, AMDGPU_FENCE_OWNER_VM);
                WARN_ON(ib->length_dw > ndw);
                r = amdgpu_sched_ib_submit_kernel_helper(adev, ring, ib, 1,
                                                         &amdgpu_vm_free_job,
                                                         AMDGPU_FENCE_OWNER_VM,
                                                         &fence);
                if (r)
                        goto error_free;

                amdgpu_bo_fence(pd, fence, true);
                fence_put(vm->page_directory_fence);
                vm->page_directory_fence = fence_get(fence);
                fence_put(fence);
        }

        if (!amdgpu_enable_scheduler || ib->length_dw == 0) {
                amdgpu_ib_free(adev, ib);
                kfree(ib);
        }

        return 0;

error_free:
        amdgpu_ib_free(adev, ib);
        kfree(ib);
        return r;
}

/**
 * amdgpu_vm_frag_ptes - add fragment information to PTEs
 *
 * @adev: amdgpu_device pointer
 * @ib: IB for the update
 * @pe_start: first PTE to handle
 * @pe_end: last PTE to handle
 * @addr: addr those PTEs should point to
 * @flags: hw mapping flags
 * @gtt_flags: GTT hw mapping flags
 *
 * Global and local mutex must be locked!
 */
static void amdgpu_vm_frag_ptes(struct amdgpu_device *adev,
                                struct amdgpu_ib *ib,
                                uint64_t pe_start, uint64_t pe_end,
                                uint64_t addr, uint32_t flags,
                                uint32_t gtt_flags)
{
        /**
         * The MC L1 TLB supports variable sized pages, based on a fragment
         * field in the PTE. When this field is set to a non-zero value, page
         * granularity is increased from 4KB to (1 << (12 + frag)). The PTE
         * flags are considered valid for all PTEs within the fragment range
         * and corresponding mappings are assumed to be physically contiguous.
         *
         * The L1 TLB can store a single PTE for the whole fragment,
         * significantly increasing the space available for translation
         * caching. This leads to large improvements in throughput when the
         * TLB is under pressure.
         *
         * The L2 TLB distributes small and large fragments into two
         * asymmetric partitions. The large fragment cache is significantly
         * larger. Thus, we try to use large fragments wherever possible.
         * Userspace can support this by aligning virtual base address and
         * allocation size to the fragment size.
         */

        /* SI and newer are optimized for 64KB */
        uint64_t frag_flags = AMDGPU_PTE_FRAG_64KB;
        uint64_t frag_align = 0x80;

        uint64_t frag_start = ALIGN(pe_start, frag_align);
        uint64_t frag_end = pe_end & ~(frag_align - 1);

        unsigned count;

        /* system pages are non continuously */
        if ((flags & AMDGPU_PTE_SYSTEM) || !(flags & AMDGPU_PTE_VALID) ||
            (frag_start >= frag_end)) {

                count = (pe_end - pe_start) / 8;
                amdgpu_vm_update_pages(adev, ib, pe_start, addr, count,
                                       AMDGPU_GPU_PAGE_SIZE, flags, gtt_flags);
                return;
        }

        /* handle the 4K area at the beginning */
        if (pe_start != frag_start) {
                count = (frag_start - pe_start) / 8;
                amdgpu_vm_update_pages(adev, ib, pe_start, addr, count,
                                       AMDGPU_GPU_PAGE_SIZE, flags, gtt_flags);
                addr += AMDGPU_GPU_PAGE_SIZE * count;
        }

        /* handle the area in the middle */
        count = (frag_end - frag_start) / 8;
        amdgpu_vm_update_pages(adev, ib, frag_start, addr, count,
                               AMDGPU_GPU_PAGE_SIZE, flags | frag_flags,
                               gtt_flags);

        /* handle the 4K area at the end */
        if (frag_end != pe_end) {
                addr += AMDGPU_GPU_PAGE_SIZE * count;
                count = (pe_end - frag_end) / 8;
                amdgpu_vm_update_pages(adev, ib, frag_end, addr, count,
                                       AMDGPU_GPU_PAGE_SIZE, flags, gtt_flags);
        }
}

/**
 * amdgpu_vm_update_ptes - make sure that page tables are valid
 *
 * @adev: amdgpu_device pointer
 * @vm: requested vm
 * @start: start of GPU address range
 * @end: end of GPU address range
 * @dst: destination address to map to
 * @flags: mapping flags
 *
 * Update the page tables in the range @start - @end (cayman+).
 *
 * Global and local mutex must be locked!
 */
static int amdgpu_vm_update_ptes(struct amdgpu_device *adev,
                                 struct amdgpu_vm *vm,
                                 struct amdgpu_ib *ib,
                                 uint64_t start, uint64_t end,
                                 uint64_t dst, uint32_t flags,
                                 uint32_t gtt_flags)
{
        uint64_t mask = AMDGPU_VM_PTE_COUNT - 1;
        uint64_t last_pte = ~0, last_dst = ~0;
        void *owner = AMDGPU_FENCE_OWNER_VM;
        unsigned count = 0;
        uint64_t addr;

        /* sync to everything on unmapping */
        if (!(flags & AMDGPU_PTE_VALID))
                owner = AMDGPU_FENCE_OWNER_UNDEFINED;

        /* walk over the address space and update the page tables */
        for (addr = start; addr < end; ) {
                uint64_t pt_idx = addr >> amdgpu_vm_block_size;
                struct amdgpu_bo *pt = vm->page_tables[pt_idx].entry.robj;
                unsigned nptes;
                uint64_t pte;
                int r;

                amdgpu_sync_resv(adev, &ib->sync, pt->tbo.resv, owner);
                r = reservation_object_reserve_shared(pt->tbo.resv);
                if (r)
                        return r;

                if ((addr & ~mask) == (end & ~mask))
                        nptes = end - addr;
                else
                        nptes = AMDGPU_VM_PTE_COUNT - (addr & mask);

                pte = amdgpu_bo_gpu_offset(pt);
                pte += (addr & mask) * 8;

                if ((last_pte + 8 * count) != pte) {

                        if (count) {
                                amdgpu_vm_frag_ptes(adev, ib, last_pte,
                                                    last_pte + 8 * count,
                                                    last_dst, flags,
                                                    gtt_flags);
                        }

                        count = nptes;
                        last_pte = pte;
                        last_dst = dst;
                } else {
                        count += nptes;
                }

                addr += nptes;
                dst += nptes * AMDGPU_GPU_PAGE_SIZE;
        }

        if (count) {
                amdgpu_vm_frag_ptes(adev, ib, last_pte,
                                    last_pte + 8 * count,
                                    last_dst, flags, gtt_flags);
        }

        return 0;
}

/**
 * amdgpu_vm_bo_update_mapping - update a mapping in the vm page table
 *
 * @adev: amdgpu_device pointer
 * @vm: requested vm
 * @mapping: mapped range and flags to use for the update
 * @addr: addr to set the area to
 * @gtt_flags: flags as they are used for GTT
 * @fence: optional resulting fence
 *
 * Fill in the page table entries for @mapping.
 * Returns 0 for success, -EINVAL for failure.
 *
 * Object have to be reserved and mutex must be locked!
 */
static int amdgpu_vm_bo_update_mapping(struct amdgpu_device *adev,
                                       struct amdgpu_vm *vm,
                                       struct amdgpu_bo_va_mapping *mapping,
                                       uint64_t addr, uint32_t gtt_flags,
                                       struct fence **fence)
{
        struct amdgpu_ring *ring = adev->vm_manager.vm_pte_funcs_ring;
        unsigned nptes, ncmds, ndw;
        uint32_t flags = gtt_flags;
        struct amdgpu_ib *ib;
        struct fence *f = NULL;
        int r;

        /* normally,bo_va->flags only contians READABLE and WIRTEABLE bit go here
         * but in case of something, we filter the flags in first place
         */
        if (!(mapping->flags & AMDGPU_PTE_READABLE))
                flags &= ~AMDGPU_PTE_READABLE;
        if (!(mapping->flags & AMDGPU_PTE_WRITEABLE))
                flags &= ~AMDGPU_PTE_WRITEABLE;

        trace_amdgpu_vm_bo_update(mapping);

        nptes = mapping->it.last - mapping->it.start + 1;

        /*
         * reserve space for one command every (1 << BLOCK_SIZE)
         *  entries or 2k dwords (whatever is smaller)
         */
        ncmds = (nptes >> min(amdgpu_vm_block_size, 11)) + 1;

        /* padding, etc. */
        ndw = 64;

        if ((flags & AMDGPU_PTE_SYSTEM) && (flags == gtt_flags)) {
                /* only copy commands needed */
                ndw += ncmds * 7;

        } else if (flags & AMDGPU_PTE_SYSTEM) {
                /* header for write data commands */
                ndw += ncmds * 4;

                /* body of write data command */
                ndw += nptes * 2;

        } else {
                /* set page commands needed */
                ndw += ncmds * 10;

                /* two extra commands for begin/end of fragment */
                ndw += 2 * 10;
        }

        /* update too big for an IB */
        if (ndw > 0xfffff)
                return -ENOMEM;

        ib = kzalloc(sizeof(struct amdgpu_ib), GFP_KERNEL);
        if (!ib)
                return -ENOMEM;

        r = amdgpu_ib_get(ring, NULL, ndw * 4, ib);
        if (r) {
                kfree(ib);
                return r;
        }

        ib->length_dw = 0;

        r = amdgpu_vm_update_ptes(adev, vm, ib, mapping->it.start,
                                  mapping->it.last + 1, addr + mapping->offset,
                                  flags, gtt_flags);

        if (r) {
                amdgpu_ib_free(adev, ib);
                kfree(ib);
                return r;
        }

        amdgpu_vm_pad_ib(adev, ib);
        WARN_ON(ib->length_dw > ndw);
        r = amdgpu_sched_ib_submit_kernel_helper(adev, ring, ib, 1,
                                                 &amdgpu_vm_free_job,
                                                 AMDGPU_FENCE_OWNER_VM,
                                                 &f);
        if (r)
                goto error_free;

        amdgpu_bo_fence(vm->page_directory, f, true);
        if (fence) {
                fence_put(*fence);
                *fence = fence_get(f);
        }
        fence_put(f);
        if (!amdgpu_enable_scheduler) {
                amdgpu_ib_free(adev, ib);
                kfree(ib);
        }
        return 0;

error_free:
        amdgpu_ib_free(adev, ib);
        kfree(ib);
        return r;
}

/**
 * amdgpu_vm_bo_update - update all BO mappings in the vm page table
 *
 * @adev: amdgpu_device pointer
 * @bo_va: requested BO and VM object
 * @mem: ttm mem
 *
 * Fill in the page table entries for @bo_va.
 * Returns 0 for success, -EINVAL for failure.
 *
 * Object have to be reserved and mutex must be locked!
 */
int amdgpu_vm_bo_update(struct amdgpu_device *adev,
                        struct amdgpu_bo_va *bo_va,
                        struct ttm_mem_reg *mem)
{
        struct amdgpu_vm *vm = bo_va->vm;
        struct amdgpu_bo_va_mapping *mapping;
        uint32_t flags;
        uint64_t addr;
        int r;

        if (mem) {
                addr = (u64)mem->start << PAGE_SHIFT;
                if (mem->mem_type != TTM_PL_TT)
                        addr += adev->vm_manager.vram_base_offset;
        } else {
                addr = 0;
        }

        flags = amdgpu_ttm_tt_pte_flags(adev, bo_va->bo->tbo.ttm, mem);

        spin_lock(&vm->status_lock);
        if (!list_empty(&bo_va->vm_status))
                list_splice_init(&bo_va->valids, &bo_va->invalids);
        spin_unlock(&vm->status_lock);

        list_for_each_entry(mapping, &bo_va->invalids, list) {
                r = amdgpu_vm_bo_update_mapping(adev, vm, mapping, addr,
                                                flags, &bo_va->last_pt_update);
                if (r)
                        return r;
        }

        if (trace_amdgpu_vm_bo_mapping_enabled()) {
                list_for_each_entry(mapping, &bo_va->valids, list)
                        trace_amdgpu_vm_bo_mapping(mapping);

                list_for_each_entry(mapping, &bo_va->invalids, list)
                        trace_amdgpu_vm_bo_mapping(mapping);
        }

        spin_lock(&vm->status_lock);
        list_splice_init(&bo_va->invalids, &bo_va->valids);
        list_del_init(&bo_va->vm_status);
        if (!mem)
                list_add(&bo_va->vm_status, &vm->cleared);
        spin_unlock(&vm->status_lock);

        return 0;
}

/**
 * amdgpu_vm_clear_freed - clear freed BOs in the PT
 *
 * @adev: amdgpu_device pointer
 * @vm: requested vm
 *
 * Make sure all freed BOs are cleared in the PT.
 * Returns 0 for success.
 *
 * PTs have to be reserved and mutex must be locked!
 */
int amdgpu_vm_clear_freed(struct amdgpu_device *adev,
                          struct amdgpu_vm *vm)
{
        struct amdgpu_bo_va_mapping *mapping;
        int r;

        spin_lock(&vm->freed_lock);
        while (!list_empty(&vm->freed)) {
                mapping = list_first_entry(&vm->freed,
                        struct amdgpu_bo_va_mapping, list);
                list_del(&mapping->list);
                spin_unlock(&vm->freed_lock);
                r = amdgpu_vm_bo_update_mapping(adev, vm, mapping, 0, 0, NULL);
                kfree(mapping);
                if (r)
                        return r;

                spin_lock(&vm->freed_lock);
        }
        spin_unlock(&vm->freed_lock);

        return 0;

}

/**
 * amdgpu_vm_clear_invalids - clear invalidated BOs in the PT
 *
 * @adev: amdgpu_device pointer
 * @vm: requested vm
 *
 * Make sure all invalidated BOs are cleared in the PT.
 * Returns 0 for success.
 *
 * PTs have to be reserved and mutex must be locked!
 */
int amdgpu_vm_clear_invalids(struct amdgpu_device *adev,
                             struct amdgpu_vm *vm, struct amdgpu_sync *sync)
{
        struct amdgpu_bo_va *bo_va = NULL;
        int r = 0;

        spin_lock(&vm->status_lock);
        while (!list_empty(&vm->invalidated)) {
                bo_va = list_first_entry(&vm->invalidated,
                        struct amdgpu_bo_va, vm_status);
                spin_unlock(&vm->status_lock);
                mutex_lock(&bo_va->mutex);
                r = amdgpu_vm_bo_update(adev, bo_va, NULL);
                mutex_unlock(&bo_va->mutex);
                if (r)
                        return r;

                spin_lock(&vm->status_lock);
        }
        spin_unlock(&vm->status_lock);

        if (bo_va)
                r = amdgpu_sync_fence(adev, sync, bo_va->last_pt_update);

        return r;
}

/**
 * amdgpu_vm_bo_add - add a bo to a specific vm
 *
 * @adev: amdgpu_device pointer
 * @vm: requested vm
 * @bo: amdgpu buffer object
 *
 * Add @bo into the requested vm (cayman+).
 * Add @bo to the list of bos associated with the vm
 * Returns newly added bo_va or NULL for failure
 *
 * Object has to be reserved!
 */
struct amdgpu_bo_va *amdgpu_vm_bo_add(struct amdgpu_device *adev,
                                      struct amdgpu_vm *vm,
                                      struct amdgpu_bo *bo)
{
        struct amdgpu_bo_va *bo_va;

        bo_va = kzalloc(sizeof(struct amdgpu_bo_va), GFP_KERNEL);
        if (bo_va == NULL) {
                return NULL;
        }
        bo_va->vm = vm;
        bo_va->bo = bo;
        bo_va->ref_count = 1;
        INIT_LIST_HEAD(&bo_va->bo_list);
        INIT_LIST_HEAD(&bo_va->valids);
        INIT_LIST_HEAD(&bo_va->invalids);

        INIT_LIST_HEAD(&bo_va->vm_status);
        mutex_init(&bo_va->mutex);
        list_add_tail(&bo_va->bo_list, &bo->va);

        return bo_va;
}

/**
 * amdgpu_vm_bo_map - map bo inside a vm
 *
 * @adev: amdgpu_device pointer
 * @bo_va: bo_va to store the address
 * @saddr: where to map the BO
 * @offset: requested offset in the BO
 * @flags: attributes of pages (read/write/valid/etc.)
 *
 * Add a mapping of the BO at the specefied addr into the VM.
 * Returns 0 for success, error for failure.
 *
 * Object has to be reserved and unreserved outside!
 */
int amdgpu_vm_bo_map(struct amdgpu_device *adev,
                     struct amdgpu_bo_va *bo_va,
                     uint64_t saddr, uint64_t offset,
                     uint64_t size, uint32_t flags)
{
        struct amdgpu_bo_va_mapping *mapping;
        struct amdgpu_vm *vm = bo_va->vm;
        struct interval_tree_node *it;
        unsigned last_pfn, pt_idx;
        uint64_t eaddr;
        int r;

        /* validate the parameters */
        if (saddr & AMDGPU_GPU_PAGE_MASK || offset & AMDGPU_GPU_PAGE_MASK ||
            size == 0 || size & AMDGPU_GPU_PAGE_MASK)
                return -EINVAL;

        /* make sure object fit at this offset */
        eaddr = saddr + size - 1;
        if ((saddr >= eaddr) || (offset + size > amdgpu_bo_size(bo_va->bo)))
                return -EINVAL;

        last_pfn = eaddr / AMDGPU_GPU_PAGE_SIZE;
        if (last_pfn >= adev->vm_manager.max_pfn) {
                dev_err(adev->dev, "va above limit (0x%08X >= 0x%08X)\n",
                        last_pfn, adev->vm_manager.max_pfn);
                return -EINVAL;
        }

        saddr /= AMDGPU_GPU_PAGE_SIZE;
        eaddr /= AMDGPU_GPU_PAGE_SIZE;

        spin_lock(&vm->it_lock);
        it = interval_tree_iter_first(&vm->va, saddr, eaddr);
        spin_unlock(&vm->it_lock);
        if (it) {
                struct amdgpu_bo_va_mapping *tmp;
                tmp = container_of(it, struct amdgpu_bo_va_mapping, it);
                /* bo and tmp overlap, invalid addr */
                dev_err(adev->dev, "bo %p va 0x%010Lx-0x%010Lx conflict with "
                        "0x%010lx-0x%010lx\n", bo_va->bo, saddr, eaddr,
                        tmp->it.start, tmp->it.last + 1);
                r = -EINVAL;
                goto error;
        }

        mapping = kmalloc(sizeof(*mapping), GFP_KERNEL);
        if (!mapping) {
                r = -ENOMEM;
                goto error;
        }

        INIT_LIST_HEAD(&mapping->list);
        mapping->it.start = saddr;
        mapping->it.last = eaddr;
        mapping->offset = offset;
        mapping->flags = flags;

        mutex_lock(&bo_va->mutex);
        list_add(&mapping->list, &bo_va->invalids);
        mutex_unlock(&bo_va->mutex);
        spin_lock(&vm->it_lock);
        interval_tree_insert(&mapping->it, &vm->va);
        spin_unlock(&vm->it_lock);
        trace_amdgpu_vm_bo_map(bo_va, mapping);

        /* Make sure the page tables are allocated */
        saddr >>= amdgpu_vm_block_size;
        eaddr >>= amdgpu_vm_block_size;

        BUG_ON(eaddr >= amdgpu_vm_num_pdes(adev));

        if (eaddr > vm->max_pde_used)
                vm->max_pde_used = eaddr;

        /* walk over the address space and allocate the page tables */
        for (pt_idx = saddr; pt_idx <= eaddr; ++pt_idx) {
                struct reservation_object *resv = vm->page_directory->tbo.resv;
                struct amdgpu_bo_list_entry *entry;
                struct amdgpu_bo *pt;

                entry = &vm->page_tables[pt_idx].entry;
                if (entry->robj)
                        continue;

                r = amdgpu_bo_create(adev, AMDGPU_VM_PTE_COUNT * 8,
                                     AMDGPU_GPU_PAGE_SIZE, true,
                                     AMDGPU_GEM_DOMAIN_VRAM,
                                     AMDGPU_GEM_CREATE_NO_CPU_ACCESS,
                                     NULL, resv, &pt);
                if (r)
                        goto error_free;

                /* Keep a reference to the page table to avoid freeing
                 * them up in the wrong order.
                 */
                pt->parent = amdgpu_bo_ref(vm->page_directory);

                r = amdgpu_vm_clear_bo(adev, pt);
                if (r) {
                        amdgpu_bo_unref(&pt);
                        goto error_free;
                }

                entry->robj = pt;
                entry->prefered_domains = AMDGPU_GEM_DOMAIN_VRAM;
                entry->allowed_domains = AMDGPU_GEM_DOMAIN_VRAM;
                entry->priority = 0;
                entry->tv.bo = &entry->robj->tbo;
                entry->tv.shared = true;
                vm->page_tables[pt_idx].addr = 0;
        }

        return 0;

error_free:
        list_del(&mapping->list);
        spin_lock(&vm->it_lock);
        interval_tree_remove(&mapping->it, &vm->va);
        spin_unlock(&vm->it_lock);
        trace_amdgpu_vm_bo_unmap(bo_va, mapping);
        kfree(mapping);

error:
        return r;
}

/**
 * amdgpu_vm_bo_unmap - remove bo mapping from vm
 *
 * @adev: amdgpu_device pointer
 * @bo_va: bo_va to remove the address from
 * @saddr: where to the BO is mapped
 *
 * Remove a mapping of the BO at the specefied addr from the VM.
 * Returns 0 for success, error for failure.
 *
 * Object has to be reserved and unreserved outside!
 */
int amdgpu_vm_bo_unmap(struct amdgpu_device *adev,
                       struct amdgpu_bo_va *bo_va,
                       uint64_t saddr)
{
        struct amdgpu_bo_va_mapping *mapping;
        struct amdgpu_vm *vm = bo_va->vm;
        bool valid = true;

        saddr /= AMDGPU_GPU_PAGE_SIZE;
        mutex_lock(&bo_va->mutex);
        list_for_each_entry(mapping, &bo_va->valids, list) {
                if (mapping->it.start == saddr)
                        break;
        }

        if (&mapping->list == &bo_va->valids) {
                valid = false;

                list_for_each_entry(mapping, &bo_va->invalids, list) {
                        if (mapping->it.start == saddr)
                                break;
                }

                if (&mapping->list == &bo_va->invalids) {
                        mutex_unlock(&bo_va->mutex);
                        return -ENOENT;
                }
        }
        mutex_unlock(&bo_va->mutex);
        list_del(&mapping->list);
        spin_lock(&vm->it_lock);
        interval_tree_remove(&mapping->it, &vm->va);
        spin_unlock(&vm->it_lock);
        trace_amdgpu_vm_bo_unmap(bo_va, mapping);

        if (valid) {
                spin_lock(&vm->freed_lock);
                list_add(&mapping->list, &vm->freed);
                spin_unlock(&vm->freed_lock);
        } else {
                kfree(mapping);
        }

        return 0;
}

/**
 * amdgpu_vm_bo_rmv - remove a bo to a specific vm
 *
 * @adev: amdgpu_device pointer
 * @bo_va: requested bo_va
 *
 * Remove @bo_va->bo from the requested vm (cayman+).
 *
 * Object have to be reserved!
 */
void amdgpu_vm_bo_rmv(struct amdgpu_device *adev,
                      struct amdgpu_bo_va *bo_va)
{
        struct amdgpu_bo_va_mapping *mapping, *next;
        struct amdgpu_vm *vm = bo_va->vm;

        list_del(&bo_va->bo_list);

        spin_lock(&vm->status_lock);
        list_del(&bo_va->vm_status);
        spin_unlock(&vm->status_lock);

        list_for_each_entry_safe(mapping, next, &bo_va->valids, list) {
                list_del(&mapping->list);
                spin_lock(&vm->it_lock);
                interval_tree_remove(&mapping->it, &vm->va);
                spin_unlock(&vm->it_lock);
                trace_amdgpu_vm_bo_unmap(bo_va, mapping);
                spin_lock(&vm->freed_lock);
                list_add(&mapping->list, &vm->freed);
                spin_unlock(&vm->freed_lock);
        }
        list_for_each_entry_safe(mapping, next, &bo_va->invalids, list) {
                list_del(&mapping->list);
                spin_lock(&vm->it_lock);
                interval_tree_remove(&mapping->it, &vm->va);
                spin_unlock(&vm->it_lock);
                kfree(mapping);
        }
        fence_put(bo_va->last_pt_update);
        mutex_destroy(&bo_va->mutex);
        kfree(bo_va);
}

/**
 * amdgpu_vm_bo_invalidate - mark the bo as invalid
 *
 * @adev: amdgpu_device pointer
 * @vm: requested vm
 * @bo: amdgpu buffer object
 *
 * Mark @bo as invalid (cayman+).
 */
void amdgpu_vm_bo_invalidate(struct amdgpu_device *adev,
                             struct amdgpu_bo *bo)
{
        struct amdgpu_bo_va *bo_va;

        list_for_each_entry(bo_va, &bo->va, bo_list) {
                spin_lock(&bo_va->vm->status_lock);
                if (list_empty(&bo_va->vm_status))
                        list_add(&bo_va->vm_status, &bo_va->vm->invalidated);
                spin_unlock(&bo_va->vm->status_lock);
        }
}

/**
 * amdgpu_vm_init - initialize a vm instance
 *
 * @adev: amdgpu_device pointer
 * @vm: requested vm
 *
 * Init @vm fields (cayman+).
 */
int amdgpu_vm_init(struct amdgpu_device *adev, struct amdgpu_vm *vm)
{
        const unsigned align = min(AMDGPU_VM_PTB_ALIGN_SIZE,
                AMDGPU_VM_PTE_COUNT * 8);
        unsigned pd_size, pd_entries;
        int i, r;

        for (i = 0; i < AMDGPU_MAX_RINGS; ++i) {
                vm->ids[i].id = 0;
                vm->ids[i].flushed_updates = NULL;
        }
        vm->va = RB_ROOT;
        spin_lock_init(&vm->status_lock);
        INIT_LIST_HEAD(&vm->invalidated);
        INIT_LIST_HEAD(&vm->cleared);
        INIT_LIST_HEAD(&vm->freed);
        spin_lock_init(&vm->it_lock);
        spin_lock_init(&vm->freed_lock);
        pd_size = amdgpu_vm_directory_size(adev);
        pd_entries = amdgpu_vm_num_pdes(adev);

        /* allocate page table array */
        vm->page_tables = drm_calloc_large(pd_entries, sizeof(struct amdgpu_vm_pt));
        if (vm->page_tables == NULL) {
                DRM_ERROR("Cannot allocate memory for page table array\n");
                return -ENOMEM;
        }

        vm->page_directory_fence = NULL;

        r = amdgpu_bo_create(adev, pd_size, align, true,
                             AMDGPU_GEM_DOMAIN_VRAM,
                             AMDGPU_GEM_CREATE_NO_CPU_ACCESS,
                             NULL, NULL, &vm->page_directory);
        if (r)
                return r;
        r = amdgpu_bo_reserve(vm->page_directory, false);
        if (r) {
                amdgpu_bo_unref(&vm->page_directory);
                vm->page_directory = NULL;
                return r;
        }
        r = amdgpu_vm_clear_bo(adev, vm->page_directory);
        amdgpu_bo_unreserve(vm->page_directory);
        if (r) {
                amdgpu_bo_unref(&vm->page_directory);
                vm->page_directory = NULL;
                return r;
        }

        return 0;
}

/**
 * amdgpu_vm_fini - tear down a vm instance
 *
 * @adev: amdgpu_device pointer
 * @vm: requested vm
 *
 * Tear down @vm (cayman+).
 * Unbind the VM and remove all bos from the vm bo list
 */
void amdgpu_vm_fini(struct amdgpu_device *adev, struct amdgpu_vm *vm)
{
        struct amdgpu_bo_va_mapping *mapping, *tmp;
        int i;

        if (!RB_EMPTY_ROOT(&vm->va)) {
                dev_err(adev->dev, "still active bo inside vm\n");
        }
        rbtree_postorder_for_each_entry_safe(mapping, tmp, &vm->va, it.rb) {
                list_del(&mapping->list);
                interval_tree_remove(&mapping->it, &vm->va);
                kfree(mapping);
        }
        list_for_each_entry_safe(mapping, tmp, &vm->freed, list) {
                list_del(&mapping->list);
                kfree(mapping);
        }

        for (i = 0; i < amdgpu_vm_num_pdes(adev); i++)
                amdgpu_bo_unref(&vm->page_tables[i].entry.robj);
        drm_free_large(vm->page_tables);

        amdgpu_bo_unref(&vm->page_directory);
        fence_put(vm->page_directory_fence);
        for (i = 0; i < AMDGPU_MAX_RINGS; ++i) {
                unsigned id = vm->ids[i].id;

                atomic_long_cmpxchg(&adev->vm_manager.ids[id].owner,
                                    (long)vm, 0);
                fence_put(vm->ids[i].flushed_updates);
        }

}

/**
 * amdgpu_vm_manager_fini - cleanup VM manager
 *
 * @adev: amdgpu_device pointer
 *
 * Cleanup the VM manager and free resources.
 */
void amdgpu_vm_manager_fini(struct amdgpu_device *adev)
{
        unsigned i;

        for (i = 0; i < AMDGPU_NUM_VM; ++i)
                fence_put(adev->vm_manager.ids[i].active);
}