/*
 * 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/radeon_drm.h>
#include "radeon.h"
#include "radeon_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.
 */

/**
 * radeon_vm_num_pde - return the number of page directory entries
 *
 * @rdev: radeon_device pointer
 *
 * Calculate the number of page directory entries (cayman+).
 */
static unsigned radeon_vm_num_pdes(struct radeon_device *rdev)
{
        return rdev->vm_manager.max_pfn >> radeon_vm_block_size;
}

/**
 * radeon_vm_directory_size - returns the size of the page directory in bytes
 *
 * @rdev: radeon_device pointer
 *
 * Calculate the size of the page directory in bytes (cayman+).
 */
static unsigned radeon_vm_directory_size(struct radeon_device *rdev)
{
        return RADEON_GPU_PAGE_ALIGN(radeon_vm_num_pdes(rdev) * 8);
}

/**
 * radeon_vm_manager_init - init the vm manager
 *
 * @rdev: radeon_device pointer
 *
 * Init the vm manager (cayman+).
 * Returns 0 for success, error for failure.
 */
int radeon_vm_manager_init(struct radeon_device *rdev)
{
        int r;

        if (!rdev->vm_manager.enabled) {
                r = radeon_asic_vm_init(rdev);
                if (r)
                        return r;

                rdev->vm_manager.enabled = true;
        }
        return 0;
}

/**
 * radeon_vm_manager_fini - tear down the vm manager
 *
 * @rdev: radeon_device pointer
 *
 * Tear down the VM manager (cayman+).
 */
void radeon_vm_manager_fini(struct radeon_device *rdev)
{
        int i;

        if (!rdev->vm_manager.enabled)
                return;

        for (i = 0; i < RADEON_NUM_VM; ++i)
                radeon_fence_unref(&rdev->vm_manager.active[i]);
        radeon_asic_vm_fini(rdev);
        rdev->vm_manager.enabled = false;
}

/**
 * radeon_vm_get_bos - add the vm BOs to a validation list
 *
 * @vm: vm providing the BOs
 * @head: head of validation list
 *
 * Add the page directory to the list of BOs to
 * validate for command submission (cayman+).
 */
struct radeon_bo_list *radeon_vm_get_bos(struct radeon_device *rdev,
                                          struct radeon_vm *vm,
                                          struct list_head *head)
{
        struct radeon_bo_list *list;
        unsigned i, idx;

        list = drm_malloc_ab(vm->max_pde_used + 2,
                             sizeof(struct radeon_bo_list));
        if (!list)
                return NULL;

        /* add the vm page table to the list */
        list[0].robj = vm->page_directory;
        list[0].prefered_domains = RADEON_GEM_DOMAIN_VRAM;
        list[0].allowed_domains = RADEON_GEM_DOMAIN_VRAM;
        list[0].tv.bo = &vm->page_directory->tbo;
        list[0].tv.shared = true;
        list[0].tiling_flags = 0;
        list_add(&list[0].tv.head, head);

        for (i = 0, idx = 1; i <= vm->max_pde_used; i++) {
                if (!vm->page_tables[i].bo)
                        continue;

                list[idx].robj = vm->page_tables[i].bo;
                list[idx].prefered_domains = RADEON_GEM_DOMAIN_VRAM;
                list[idx].allowed_domains = RADEON_GEM_DOMAIN_VRAM;
                list[idx].tv.bo = &list[idx].robj->tbo;
                list[idx].tv.shared = true;
                list[idx].tiling_flags = 0;
                list_add(&list[idx++].tv.head, head);
        }

        return list;
}

/**
 * radeon_vm_grab_id - allocate the next free VMID
 *
 * @rdev: radeon_device pointer
 * @vm: vm to allocate id for
 * @ring: ring we want to submit job to
 *
 * Allocate an id for the vm (cayman+).
 * Returns the fence we need to sync to (if any).
 *
 * Global and local mutex must be locked!
 */
struct radeon_fence *radeon_vm_grab_id(struct radeon_device *rdev,
                                       struct radeon_vm *vm, int ring)
{
        struct radeon_fence *best[RADEON_NUM_RINGS] = {};
        struct radeon_vm_id *vm_id = &vm->ids[ring];

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

        /* check if the id is still valid */
        if (vm_id->id && vm_id->last_id_use &&
            vm_id->last_id_use == rdev->vm_manager.active[vm_id->id])
                return NULL;

        /* 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 < rdev->vm_manager.nvm; ++i) {
                struct radeon_fence *fence = rdev->vm_manager.active[i];

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

                if (radeon_fence_is_earlier(fence, best[fence->ring])) {
                        best[fence->ring] = fence;
                        choices[fence->ring == ring ? 0 : 1] = i;
                }
        }

        for (i = 0; i < 2; ++i) {
                if (choices[i]) {
                        vm_id->id = choices[i];
                        trace_radeon_vm_grab_id(choices[i], ring);
                        return rdev->vm_manager.active[choices[i]];
                }
        }

        /* should never happen */
        BUG();
        return NULL;
}

/**
 * radeon_vm_flush - hardware flush the vm
 *
 * @rdev: radeon_device pointer
 * @vm: vm we want to flush
 * @ring: ring to use for flush
 * @updates: last vm update that is waited for
 *
 * Flush the vm (cayman+).
 *
 * Global and local mutex must be locked!
 */
void radeon_vm_flush(struct radeon_device *rdev,
                     struct radeon_vm *vm,
                     int ring, struct radeon_fence *updates)
{
        uint64_t pd_addr = radeon_bo_gpu_offset(vm->page_directory);
        struct radeon_vm_id *vm_id = &vm->ids[ring];

        if (pd_addr != vm_id->pd_gpu_addr || !vm_id->flushed_updates ||
            radeon_fence_is_earlier(vm_id->flushed_updates, updates)) {

                trace_radeon_vm_flush(pd_addr, ring, vm->ids[ring].id);
                radeon_fence_unref(&vm_id->flushed_updates);
                vm_id->flushed_updates = radeon_fence_ref(updates);
                vm_id->pd_gpu_addr = pd_addr;
                radeon_ring_vm_flush(rdev, &rdev->ring[ring],
                                     vm_id->id, vm_id->pd_gpu_addr);

        }
}

/**
 * radeon_vm_fence - remember fence for vm
 *
 * @rdev: radeon_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 radeon_vm_fence(struct radeon_device *rdev,
                     struct radeon_vm *vm,
                     struct radeon_fence *fence)
{
        unsigned vm_id = vm->ids[fence->ring].id;

        radeon_fence_unref(&rdev->vm_manager.active[vm_id]);
        rdev->vm_manager.active[vm_id] = radeon_fence_ref(fence);

        radeon_fence_unref(&vm->ids[fence->ring].last_id_use);
        vm->ids[fence->ring].last_id_use = radeon_fence_ref(fence);
}

/**
 * radeon_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 radeon_bo_va *radeon_vm_bo_find(struct radeon_vm *vm,
                                       struct radeon_bo *bo)
{
        struct radeon_bo_va *bo_va;

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

/**
 * radeon_vm_bo_add - add a bo to a specific vm
 *
 * @rdev: radeon_device pointer
 * @vm: requested vm
 * @bo: radeon 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 radeon_bo_va *radeon_vm_bo_add(struct radeon_device *rdev,
                                      struct radeon_vm *vm,
                                      struct radeon_bo *bo)
{
        struct radeon_bo_va *bo_va;

        bo_va = kzalloc(sizeof(struct radeon_bo_va), GFP_KERNEL);
        if (bo_va == NULL) {
                return NULL;
        }
        bo_va->vm = vm;
        bo_va->bo = bo;
        bo_va->it.start = 0;
        bo_va->it.last = 0;
        bo_va->flags = 0;
        bo_va->ref_count = 1;
        INIT_LIST_HEAD(&bo_va->bo_list);
        INIT_LIST_HEAD(&bo_va->vm_status);

        mutex_lock(&vm->mutex);
        list_add_tail(&bo_va->bo_list, &bo->va);
        mutex_unlock(&vm->mutex);

        return bo_va;
}

/**
 * radeon_vm_set_pages - helper to call the right asic function
 *
 * @rdev: radeon_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
 *
 * Traces the parameters and calls the right asic functions
 * to setup the page table using the DMA.
 */
static void radeon_vm_set_pages(struct radeon_device *rdev,
                                struct radeon_ib *ib,
                                uint64_t pe,
                                uint64_t addr, unsigned count,
                                uint32_t incr, uint32_t flags)
{
        trace_radeon_vm_set_page(pe, addr, count, incr, flags);

        if ((flags & R600_PTE_GART_MASK) == R600_PTE_GART_MASK) {
                uint64_t src = rdev->gart.table_addr + (addr >> 12) * 8;
                radeon_asic_vm_copy_pages(rdev, ib, pe, src, count);

        } else if ((flags & R600_PTE_SYSTEM) || (count < 3)) {
                radeon_asic_vm_write_pages(rdev, ib, pe, addr,
                                           count, incr, flags);

        } else {
                radeon_asic_vm_set_pages(rdev, ib, pe, addr,
                                         count, incr, flags);
        }
}

/**
 * radeon_vm_clear_bo - initially clear the page dir/table
 *
 * @rdev: radeon_device pointer
 * @bo: bo to clear
 */
static int radeon_vm_clear_bo(struct radeon_device *rdev,
                              struct radeon_bo *bo)
{
        struct radeon_ib ib;
        unsigned entries;
        uint64_t addr;
        int r;

        r = radeon_bo_reserve(bo, false);
        if (r)
                return r;

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

        addr = radeon_bo_gpu_offset(bo);
        entries = radeon_bo_size(bo) / 8;

        r = radeon_ib_get(rdev, R600_RING_TYPE_DMA_INDEX, &ib, NULL, 256);
        if (r)
                goto error_unreserve;

        ib.length_dw = 0;

        radeon_vm_set_pages(rdev, &ib, addr, 0, entries, 0, 0);
        radeon_asic_vm_pad_ib(rdev, &ib);
        WARN_ON(ib.length_dw > 64);

        r = radeon_ib_schedule(rdev, &ib, NULL, false);
        if (r)
                goto error_free;

        ib.fence->is_vm_update = true;
        radeon_bo_fence(bo, ib.fence, false);

error_free:
        radeon_ib_free(rdev, &ib);

error_unreserve:
        radeon_bo_unreserve(bo);
        return r;
}

/**
 * radeon_vm_bo_set_addr - set bos virtual address inside a vm
 *
 * @rdev: radeon_device pointer
 * @bo_va: bo_va to store the address
 * @soffset: requested offset of the buffer in the VM address space
 * @flags: attributes of pages (read/write/valid/etc.)
 *
 * Set offset of @bo_va (cayman+).
 * Validate and set the offset requested within the vm address space.
 * Returns 0 for success, error for failure.
 *
 * Object has to be reserved and gets unreserved by this function!
 */
int radeon_vm_bo_set_addr(struct radeon_device *rdev,
                          struct radeon_bo_va *bo_va,
                          uint64_t soffset,
                          uint32_t flags)
{
        uint64_t size = radeon_bo_size(bo_va->bo);
        struct radeon_vm *vm = bo_va->vm;
        unsigned last_pfn, pt_idx;
        uint64_t eoffset;
        int r;

        if (soffset) {
                /* make sure object fit at this offset */
                eoffset = soffset + size - 1;
                if (soffset >= eoffset) {
                        r = -EINVAL;
                        goto error_unreserve;
                }

                last_pfn = eoffset / RADEON_GPU_PAGE_SIZE;
                if (last_pfn >= rdev->vm_manager.max_pfn) {
                        dev_err(rdev->dev, "va above limit (0x%08X >= 0x%08X)\n",
                                last_pfn, rdev->vm_manager.max_pfn);
                        r = -EINVAL;
                        goto error_unreserve;
                }

        } else {
                eoffset = last_pfn = 0;
        }

        mutex_lock(&vm->mutex);
        soffset /= RADEON_GPU_PAGE_SIZE;
        eoffset /= RADEON_GPU_PAGE_SIZE;
        if (soffset || eoffset) {
                struct interval_tree_node *it;
                it = interval_tree_iter_first(&vm->va, soffset, eoffset);
                if (it && it != &bo_va->it) {
                        struct radeon_bo_va *tmp;
                        tmp = container_of(it, struct radeon_bo_va, it);
                        /* bo and tmp overlap, invalid offset */
                        dev_err(rdev->dev, "bo %p va 0x%010Lx conflict with "
                                "(bo %p 0x%010lx 0x%010lx)\n", bo_va->bo,
                                soffset, tmp->bo, tmp->it.start, tmp->it.last);
                        mutex_unlock(&vm->mutex);
                        r = -EINVAL;
                        goto error_unreserve;
                }
        }

        if (bo_va->it.start || bo_va->it.last) {
                /* add a clone of the bo_va to clear the old address */
                struct radeon_bo_va *tmp;
                tmp = kzalloc(sizeof(struct radeon_bo_va), GFP_KERNEL);
                if (!tmp) {
                        mutex_unlock(&vm->mutex);
                        r = -ENOMEM;
                        goto error_unreserve;
                }
                tmp->it.start = bo_va->it.start;
                tmp->it.last = bo_va->it.last;
                tmp->vm = vm;
                tmp->bo = radeon_bo_ref(bo_va->bo);

                interval_tree_remove(&bo_va->it, &vm->va);
                spin_lock(&vm->status_lock);
                bo_va->it.start = 0;
                bo_va->it.last = 0;
                list_del_init(&bo_va->vm_status);
                list_add(&tmp->vm_status, &vm->freed);
                spin_unlock(&vm->status_lock);
        }

        if (soffset || eoffset) {
                spin_lock(&vm->status_lock);
                bo_va->it.start = soffset;
                bo_va->it.last = eoffset;
                list_add(&bo_va->vm_status, &vm->cleared);
                spin_unlock(&vm->status_lock);
                interval_tree_insert(&bo_va->it, &vm->va);
        }

        bo_va->flags = flags;

        soffset >>= radeon_vm_block_size;
        eoffset >>= radeon_vm_block_size;

        BUG_ON(eoffset >= radeon_vm_num_pdes(rdev));

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

        radeon_bo_unreserve(bo_va->bo);

        /* walk over the address space and allocate the page tables */
        for (pt_idx = soffset; pt_idx <= eoffset; ++pt_idx) {
                struct radeon_bo *pt;

                if (vm->page_tables[pt_idx].bo)
                        continue;

                /* drop mutex to allocate and clear page table */
                mutex_unlock(&vm->mutex);

                r = radeon_bo_create(rdev, RADEON_VM_PTE_COUNT * 8,
                                     RADEON_GPU_PAGE_SIZE, true,
                                     RADEON_GEM_DOMAIN_VRAM, 0,
                                     NULL, NULL, &pt);
                if (r)
                        return r;

                r = radeon_vm_clear_bo(rdev, pt);
                if (r) {
                        radeon_bo_unref(&pt);
                        return r;
                }

                /* aquire mutex again */
                mutex_lock(&vm->mutex);
                if (vm->page_tables[pt_idx].bo) {
                        /* someone else allocated the pt in the meantime */
                        mutex_unlock(&vm->mutex);
                        radeon_bo_unref(&pt);
                        mutex_lock(&vm->mutex);
                        continue;
                }

                vm->page_tables[pt_idx].addr = 0;
                vm->page_tables[pt_idx].bo = pt;
        }

        mutex_unlock(&vm->mutex);
        return 0;

error_unreserve:
        radeon_bo_unreserve(bo_va->bo);
        return r;
}

/**
 * radeon_vm_map_gart - get the physical address of a gart page
 *
 * @rdev: radeon_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 radeon_vm_map_gart(struct radeon_device *rdev, uint64_t addr)
{
        uint64_t result;

        /* page table offset */
        result = rdev->gart.pages_entry[addr >> RADEON_GPU_PAGE_SHIFT];
        result &= ~RADEON_GPU_PAGE_MASK;

        return result;
}

/**
 * radeon_vm_page_flags - translate page flags to what the hw uses
 *
 * @flags: flags comming from userspace
 *
 * Translate the flags the userspace ABI uses to hw flags.
 */
static uint32_t radeon_vm_page_flags(uint32_t flags)
{
        uint32_t hw_flags = 0;

        hw_flags |= (flags & RADEON_VM_PAGE_VALID) ? R600_PTE_VALID : 0;
        hw_flags |= (flags & RADEON_VM_PAGE_READABLE) ? R600_PTE_READABLE : 0;
        hw_flags |= (flags & RADEON_VM_PAGE_WRITEABLE) ? R600_PTE_WRITEABLE : 0;
        if (flags & RADEON_VM_PAGE_SYSTEM) {
                hw_flags |= R600_PTE_SYSTEM;
                hw_flags |= (flags & RADEON_VM_PAGE_SNOOPED) ? R600_PTE_SNOOPED : 0;
        }
        return hw_flags;
}

/**
 * radeon_vm_update_pdes - make sure that page directory is valid
 *
 * @rdev: radeon_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 radeon_vm_update_page_directory(struct radeon_device *rdev,
                                    struct radeon_vm *vm)
{
        struct radeon_bo *pd = vm->page_directory;
        uint64_t pd_addr = radeon_bo_gpu_offset(pd);
        uint32_t incr = RADEON_VM_PTE_COUNT * 8;
        uint64_t last_pde = ~0, last_pt = ~0;
        unsigned count = 0, pt_idx, ndw;
        struct radeon_ib ib;
        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;

        r = radeon_ib_get(rdev, R600_RING_TYPE_DMA_INDEX, &ib, NULL, ndw * 4);
        if (r)
                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 radeon_bo *bo = vm->page_tables[pt_idx].bo;
                uint64_t pde, pt;

                if (bo == NULL)
                        continue;

                pt = radeon_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) {
                                radeon_vm_set_pages(rdev, &ib, last_pde,
                                                    last_pt, count, incr,
                                                    R600_PTE_VALID);
                        }

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

        if (count)
                radeon_vm_set_pages(rdev, &ib, last_pde, last_pt, count,
                                    incr, R600_PTE_VALID);

        if (ib.length_dw != 0) {
                radeon_asic_vm_pad_ib(rdev, &ib);

                radeon_sync_resv(rdev, &ib.sync, pd->tbo.resv, true);
                WARN_ON(ib.length_dw > ndw);
                r = radeon_ib_schedule(rdev, &ib, NULL, false);
                if (r) {
                        radeon_ib_free(rdev, &ib);
                        return r;
                }
                ib.fence->is_vm_update = true;
                radeon_bo_fence(pd, ib.fence, false);
        }
        radeon_ib_free(rdev, &ib);

        return 0;
}

/**
 * radeon_vm_frag_ptes - add fragment information to PTEs
 *
 * @rdev: radeon_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
 *
 * Global and local mutex must be locked!
 */
static void radeon_vm_frag_ptes(struct radeon_device *rdev,
                                struct radeon_ib *ib,
                                uint64_t pe_start, uint64_t pe_end,
                                uint64_t addr, uint32_t 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.
         */

        /* NI is optimized for 256KB fragments, SI and newer for 64KB */
        uint64_t frag_flags = ((rdev->family == CHIP_CAYMAN) ||
                               (rdev->family == CHIP_ARUBA)) ?
                        R600_PTE_FRAG_256KB : R600_PTE_FRAG_64KB;
        uint64_t frag_align = ((rdev->family == CHIP_CAYMAN) ||
                               (rdev->family == CHIP_ARUBA)) ? 0x200 : 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 & R600_PTE_SYSTEM) || !(flags & R600_PTE_VALID) ||
            (frag_start >= frag_end)) {

                count = (pe_end - pe_start) / 8;
                radeon_vm_set_pages(rdev, ib, pe_start, addr, count,
                                    RADEON_GPU_PAGE_SIZE, flags);
                return;
        }

        /* handle the 4K area at the beginning */
        if (pe_start != frag_start) {
                count = (frag_start - pe_start) / 8;
                radeon_vm_set_pages(rdev, ib, pe_start, addr, count,
                                    RADEON_GPU_PAGE_SIZE, flags);
                addr += RADEON_GPU_PAGE_SIZE * count;
        }

        /* handle the area in the middle */
        count = (frag_end - frag_start) / 8;
        radeon_vm_set_pages(rdev, ib, frag_start, addr, count,
                            RADEON_GPU_PAGE_SIZE, flags | frag_flags);

        /* handle the 4K area at the end */
        if (frag_end != pe_end) {
                addr += RADEON_GPU_PAGE_SIZE * count;
                count = (pe_end - frag_end) / 8;
                radeon_vm_set_pages(rdev, ib, frag_end, addr, count,
                                    RADEON_GPU_PAGE_SIZE, flags);
        }
}

/**
 * radeon_vm_update_ptes - make sure that page tables are valid
 *
 * @rdev: radeon_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 radeon_vm_update_ptes(struct radeon_device *rdev,
                                 struct radeon_vm *vm,
                                 struct radeon_ib *ib,
                                 uint64_t start, uint64_t end,
                                 uint64_t dst, uint32_t flags)
{
        uint64_t mask = RADEON_VM_PTE_COUNT - 1;
        uint64_t last_pte = ~0, last_dst = ~0;
        unsigned count = 0;
        uint64_t addr;

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

                radeon_sync_resv(rdev, &ib->sync, pt->tbo.resv, true);
                r = reservation_object_reserve_shared(pt->tbo.resv);
                if (r)
                        return r;

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

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

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

                        if (count) {
                                radeon_vm_frag_ptes(rdev, ib, last_pte,
                                                    last_pte + 8 * count,
                                                    last_dst, flags);
                        }

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

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

        if (count) {
                radeon_vm_frag_ptes(rdev, ib, last_pte,
                                    last_pte + 8 * count,
                                    last_dst, flags);
        }

        return 0;
}

/**
 * radeon_vm_fence_pts - fence page tables after an update
 *
 * @vm: requested vm
 * @start: start of GPU address range
 * @end: end of GPU address range
 * @fence: fence to use
 *
 * Fence the page tables in the range @start - @end (cayman+).
 *
 * Global and local mutex must be locked!
 */
static void radeon_vm_fence_pts(struct radeon_vm *vm,
                                uint64_t start, uint64_t end,
                                struct radeon_fence *fence)
{
        unsigned i;

        start >>= radeon_vm_block_size;
        end = (end - 1) >> radeon_vm_block_size;

        for (i = start; i <= end; ++i)
                radeon_bo_fence(vm->page_tables[i].bo, fence, true);
}

/**
 * radeon_vm_bo_update - map a bo into the vm page table
 *
 * @rdev: radeon_device pointer
 * @vm: requested vm
 * @bo: radeon buffer object
 * @mem: ttm mem
 *
 * Fill in the page table entries for @bo (cayman+).
 * Returns 0 for success, -EINVAL for failure.
 *
 * Object have to be reserved and mutex must be locked!
 */
int radeon_vm_bo_update(struct radeon_device *rdev,
                        struct radeon_bo_va *bo_va,
                        struct ttm_mem_reg *mem)
{
        struct radeon_vm *vm = bo_va->vm;
        struct radeon_ib ib;
        unsigned nptes, ncmds, ndw;
        uint64_t addr;
        uint32_t flags;
        int r;

        if (!bo_va->it.start) {
                dev_err(rdev->dev, "bo %p don't has a mapping in vm %p\n",
                        bo_va->bo, vm);
                return -EINVAL;
        }

        spin_lock(&vm->status_lock);
        if (mem) {
                if (list_empty(&bo_va->vm_status)) {
                        spin_unlock(&vm->status_lock);
                        return 0;
                }
                list_del_init(&bo_va->vm_status);
        } else {
                list_del(&bo_va->vm_status);
                list_add(&bo_va->vm_status, &vm->cleared);
        }
        spin_unlock(&vm->status_lock);

        bo_va->flags &= ~RADEON_VM_PAGE_VALID;
        bo_va->flags &= ~RADEON_VM_PAGE_SYSTEM;
        bo_va->flags &= ~RADEON_VM_PAGE_SNOOPED;
        if (bo_va->bo && radeon_ttm_tt_is_readonly(bo_va->bo->tbo.ttm))
                bo_va->flags &= ~RADEON_VM_PAGE_WRITEABLE;

        if (mem) {
                addr = mem->start << PAGE_SHIFT;
                if (mem->mem_type != TTM_PL_SYSTEM) {
                        bo_va->flags |= RADEON_VM_PAGE_VALID;
                }
                if (mem->mem_type == TTM_PL_TT) {
                        bo_va->flags |= RADEON_VM_PAGE_SYSTEM;
                        if (!(bo_va->bo->flags & (RADEON_GEM_GTT_WC | RADEON_GEM_GTT_UC)))
                                bo_va->flags |= RADEON_VM_PAGE_SNOOPED;

                } else {
                        addr += rdev->vm_manager.vram_base_offset;
                }
        } else {
                addr = 0;
        }

        trace_radeon_vm_bo_update(bo_va);

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

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

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

        flags = radeon_vm_page_flags(bo_va->flags);
        if ((flags & R600_PTE_GART_MASK) == R600_PTE_GART_MASK) {
                /* only copy commands needed */
                ndw += ncmds * 7;

        } else if (flags & R600_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;

        r = radeon_ib_get(rdev, R600_RING_TYPE_DMA_INDEX, &ib, NULL, ndw * 4);
        if (r)

                return r;
        ib.length_dw = 0;

        if (!(bo_va->flags & RADEON_VM_PAGE_VALID)) {
                unsigned i;

                for (i = 0; i < RADEON_NUM_RINGS; ++i)
                        radeon_sync_fence(&ib.sync, vm->ids[i].last_id_use);
        }

        r = radeon_vm_update_ptes(rdev, vm, &ib, bo_va->it.start,
                                  bo_va->it.last + 1, addr,
                                  radeon_vm_page_flags(bo_va->flags));
        if (r) {
                radeon_ib_free(rdev, &ib);
                return r;
        }

        radeon_asic_vm_pad_ib(rdev, &ib);
        WARN_ON(ib.length_dw > ndw);

        r = radeon_ib_schedule(rdev, &ib, NULL, false);
        if (r) {
                radeon_ib_free(rdev, &ib);
                return r;
        }
        ib.fence->is_vm_update = true;
        radeon_vm_fence_pts(vm, bo_va->it.start, bo_va->it.last + 1, ib.fence);
        radeon_fence_unref(&bo_va->last_pt_update);
        bo_va->last_pt_update = radeon_fence_ref(ib.fence);
        radeon_ib_free(rdev, &ib);

        return 0;
}

/**
 * radeon_vm_clear_freed - clear freed BOs in the PT
 *
 * @rdev: radeon_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 radeon_vm_clear_freed(struct radeon_device *rdev,
                          struct radeon_vm *vm)
{
        struct radeon_bo_va *bo_va;
        int r = 0;

        spin_lock(&vm->status_lock);
        while (!list_empty(&vm->freed)) {
                bo_va = list_first_entry(&vm->freed,
                        struct radeon_bo_va, vm_status);
                spin_unlock(&vm->status_lock);

                r = radeon_vm_bo_update(rdev, bo_va, NULL);
                radeon_bo_unref(&bo_va->bo);
                radeon_fence_unref(&bo_va->last_pt_update);
                spin_lock(&vm->status_lock);
                list_del(&bo_va->vm_status);
                kfree(bo_va);
                if (r)
                        break;

        }
        spin_unlock(&vm->status_lock);
        return r;

}

/**
 * radeon_vm_clear_invalids - clear invalidated BOs in the PT
 *
 * @rdev: radeon_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 radeon_vm_clear_invalids(struct radeon_device *rdev,
                             struct radeon_vm *vm)
{
        struct radeon_bo_va *bo_va;
        int r;

        spin_lock(&vm->status_lock);
        while (!list_empty(&vm->invalidated)) {
                bo_va = list_first_entry(&vm->invalidated,
                        struct radeon_bo_va, vm_status);
                spin_unlock(&vm->status_lock);

                r = radeon_vm_bo_update(rdev, bo_va, NULL);
                if (r)
                        return r;

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

        return 0;
}

/**
 * radeon_vm_bo_rmv - remove a bo to a specific vm
 *
 * @rdev: radeon_device pointer
 * @bo_va: requested bo_va
 *
 * Remove @bo_va->bo from the requested vm (cayman+).
 *
 * Object have to be reserved!
 */
void radeon_vm_bo_rmv(struct radeon_device *rdev,
                      struct radeon_bo_va *bo_va)
{
        struct radeon_vm *vm = bo_va->vm;

        list_del(&bo_va->bo_list);

        mutex_lock(&vm->mutex);
        if (bo_va->it.start || bo_va->it.last)
                interval_tree_remove(&bo_va->it, &vm->va);

        spin_lock(&vm->status_lock);
        list_del(&bo_va->vm_status);
        if (bo_va->it.start || bo_va->it.last) {
                bo_va->bo = radeon_bo_ref(bo_va->bo);
                list_add(&bo_va->vm_status, &vm->freed);
        } else {
                radeon_fence_unref(&bo_va->last_pt_update);
                kfree(bo_va);
        }
        spin_unlock(&vm->status_lock);

        mutex_unlock(&vm->mutex);
}

/**
 * radeon_vm_bo_invalidate - mark the bo as invalid
 *
 * @rdev: radeon_device pointer
 * @vm: requested vm
 * @bo: radeon buffer object
 *
 * Mark @bo as invalid (cayman+).
 */
void radeon_vm_bo_invalidate(struct radeon_device *rdev,
                             struct radeon_bo *bo)
{
        struct radeon_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) &&
                    (bo_va->it.start || bo_va->it.last))
                        list_add(&bo_va->vm_status, &bo_va->vm->invalidated);
                spin_unlock(&bo_va->vm->status_lock);
        }
}

/**
 * radeon_vm_init - initialize a vm instance
 *
 * @rdev: radeon_device pointer
 * @vm: requested vm
 *
 * Init @vm fields (cayman+).
 */
int radeon_vm_init(struct radeon_device *rdev, struct radeon_vm *vm)
{
        const unsigned align = min(RADEON_VM_PTB_ALIGN_SIZE,
                RADEON_VM_PTE_COUNT * 8);
        unsigned pd_size, pd_entries, pts_size;
        int i, r;

        vm->ib_bo_va = NULL;
        for (i = 0; i < RADEON_NUM_RINGS; ++i) {
                vm->ids[i].id = 0;
                vm->ids[i].flushed_updates = NULL;
                vm->ids[i].last_id_use = NULL;
        }
        mutex_init(&vm->mutex);
        vm->va = RB_ROOT;
        spin_lock_init(&vm->status_lock);
        INIT_LIST_HEAD(&vm->invalidated);
        INIT_LIST_HEAD(&vm->freed);
        INIT_LIST_HEAD(&vm->cleared);

        pd_size = radeon_vm_directory_size(rdev);
        pd_entries = radeon_vm_num_pdes(rdev);

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

        r = radeon_bo_create(rdev, pd_size, align, true,
                             RADEON_GEM_DOMAIN_VRAM, 0, NULL,
                             NULL, &vm->page_directory);
        if (r)
                return r;

        r = radeon_vm_clear_bo(rdev, vm->page_directory);
        if (r) {
                radeon_bo_unref(&vm->page_directory);
                vm->page_directory = NULL;
                return r;
        }

        return 0;
}

/**
 * radeon_vm_fini - tear down a vm instance
 *
 * @rdev: radeon_device pointer
 * @vm: requested vm
 *
 * Tear down @vm (cayman+).
 * Unbind the VM and remove all bos from the vm bo list
 */
void radeon_vm_fini(struct radeon_device *rdev, struct radeon_vm *vm)
{
        struct radeon_bo_va *bo_va, *tmp;
        int i, r;

        if (!RB_EMPTY_ROOT(&vm->va)) {
                dev_err(rdev->dev, "still active bo inside vm\n");
        }
        rbtree_postorder_for_each_entry_safe(bo_va, tmp, &vm->va, it.rb) {
                interval_tree_remove(&bo_va->it, &vm->va);
                r = radeon_bo_reserve(bo_va->bo, false);
                if (!r) {
                        list_del_init(&bo_va->bo_list);
                        radeon_bo_unreserve(bo_va->bo);
                        radeon_fence_unref(&bo_va->last_pt_update);
                        kfree(bo_va);
                }
        }
        list_for_each_entry_safe(bo_va, tmp, &vm->freed, vm_status) {
                radeon_bo_unref(&bo_va->bo);
                radeon_fence_unref(&bo_va->last_pt_update);
                kfree(bo_va);
        }

        for (i = 0; i < radeon_vm_num_pdes(rdev); i++)
                radeon_bo_unref(&vm->page_tables[i].bo);
        kfree(vm->page_tables);

        radeon_bo_unref(&vm->page_directory);

        for (i = 0; i < RADEON_NUM_RINGS; ++i) {
                radeon_fence_unref(&vm->ids[i].flushed_updates);
                radeon_fence_unref(&vm->ids[i].last_id_use);
        }

        mutex_destroy(&vm->mutex);
}