/*
 * Copyright 2010 Red Hat Inc.
 *
 * 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: Ben Skeggs
 */

#include "drmP.h"
#include "nouveau_drv.h"
#include "nouveau_mm.h"
#include "nouveau_vm.h"

void
nouveau_vm_map_at(struct nouveau_vma *vma, u64 delta, struct nouveau_vram *vram)
{
        struct nouveau_vm *vm = vma->vm;
        struct nouveau_mm_node *r;
        int big = vma->node->type != vm->spg_shift;
        u32 offset = vma->node->offset + (delta >> 12);
        u32 bits = vma->node->type - 12;
        u32 pde  = (offset >> vm->pgt_bits) - vm->fpde;
        u32 pte  = (offset & ((1 << vm->pgt_bits) - 1)) >> bits;
        u32 max  = 1 << (vm->pgt_bits - bits);
        u32 end, len;

        list_for_each_entry(r, &vram->regions, rl_entry) {
                u64 phys = (u64)r->offset << 12;
                u32 num  = r->length >> bits;

                while (num) {
                        struct nouveau_gpuobj *pgt = vm->pgt[pde].obj[big];

                        end = (pte + num);
                        if (unlikely(end >= max))
                                end = max;
                        len = end - pte;

                        vm->map(vma, pgt, vram, pte, len, phys);

                        num -= len;
                        pte += len;
                        if (unlikely(end >= max)) {
                                pde++;
                                pte = 0;
                        }
                }
        }

        vm->flush(vm);
}

void
nouveau_vm_map(struct nouveau_vma *vma, struct nouveau_vram *vram)
{
        nouveau_vm_map_at(vma, 0, vram);
}

void
nouveau_vm_map_sg(struct nouveau_vma *vma, u64 delta, u64 length,
                  dma_addr_t *list)
{
        struct nouveau_vm *vm = vma->vm;
        int big = vma->node->type != vm->spg_shift;
        u32 offset = vma->node->offset + (delta >> 12);
        u32 bits = vma->node->type - 12;
        u32 num  = length >> vma->node->type;
        u32 pde  = (offset >> vm->pgt_bits) - vm->fpde;
        u32 pte  = (offset & ((1 << vm->pgt_bits) - 1)) >> bits;
        u32 max  = 1 << (vm->pgt_bits - bits);
        u32 end, len;

        while (num) {
                struct nouveau_gpuobj *pgt = vm->pgt[pde].obj[big];

                end = (pte + num);
                if (unlikely(end >= max))
                        end = max;
                len = end - pte;

                vm->map_sg(vma, pgt, pte, list, len);

                num  -= len;
                pte  += len;
                list += len;
                if (unlikely(end >= max)) {
                        pde++;
                        pte = 0;
                }
        }

        vm->flush(vm);
}

void
nouveau_vm_unmap_at(struct nouveau_vma *vma, u64 delta, u64 length)
{
        struct nouveau_vm *vm = vma->vm;
        int big = vma->node->type != vm->spg_shift;
        u32 offset = vma->node->offset + (delta >> 12);
        u32 bits = vma->node->type - 12;
        u32 num  = length >> vma->node->type;
        u32 pde  = (offset >> vm->pgt_bits) - vm->fpde;
        u32 pte  = (offset & ((1 << vm->pgt_bits) - 1)) >> bits;
        u32 max  = 1 << (vm->pgt_bits - bits);
        u32 end, len;

        while (num) {
                struct nouveau_gpuobj *pgt = vm->pgt[pde].obj[big];

                end = (pte + num);
                if (unlikely(end >= max))
                        end = max;
                len = end - pte;

                vm->unmap(pgt, pte, len);

                num -= len;
                pte += len;
                if (unlikely(end >= max)) {
                        pde++;
                        pte = 0;
                }
        }

        vm->flush(vm);
}

void
nouveau_vm_unmap(struct nouveau_vma *vma)
{
        nouveau_vm_unmap_at(vma, 0, (u64)vma->node->length << 12);
}

static void
nouveau_vm_unmap_pgt(struct nouveau_vm *vm, int big, u32 fpde, u32 lpde)
{
        struct nouveau_vm_pgd *vpgd;
        struct nouveau_vm_pgt *vpgt;
        struct nouveau_gpuobj *pgt;
        u32 pde;

        for (pde = fpde; pde <= lpde; pde++) {
                vpgt = &vm->pgt[pde - vm->fpde];
                if (--vpgt->refcount[big])
                        continue;

                pgt = vpgt->obj[big];
                vpgt->obj[big] = NULL;

                list_for_each_entry(vpgd, &vm->pgd_list, head) {
                        vm->map_pgt(vpgd->obj, pde, vpgt->obj);
                }

                mutex_unlock(&vm->mm->mutex);
                nouveau_gpuobj_ref(NULL, &pgt);
                mutex_lock(&vm->mm->mutex);
        }
}

static int
nouveau_vm_map_pgt(struct nouveau_vm *vm, u32 pde, u32 type)
{
        struct nouveau_vm_pgt *vpgt = &vm->pgt[pde - vm->fpde];
        struct nouveau_vm_pgd *vpgd;
        struct nouveau_gpuobj *pgt;
        int big = (type != vm->spg_shift);
        u32 pgt_size;
        int ret;

        pgt_size  = (1 << (vm->pgt_bits + 12)) >> type;
        pgt_size *= 8;

        mutex_unlock(&vm->mm->mutex);
        ret = nouveau_gpuobj_new(vm->dev, NULL, pgt_size, 0x1000,
                                 NVOBJ_FLAG_ZERO_ALLOC, &pgt);
        mutex_lock(&vm->mm->mutex);
        if (unlikely(ret))
                return ret;

        /* someone beat us to filling the PDE while we didn't have the lock */
        if (unlikely(vpgt->refcount[big]++)) {
                mutex_unlock(&vm->mm->mutex);
                nouveau_gpuobj_ref(NULL, &pgt);
                mutex_lock(&vm->mm->mutex);
                return 0;
        }

        vpgt->obj[big] = pgt;
        list_for_each_entry(vpgd, &vm->pgd_list, head) {
                vm->map_pgt(vpgd->obj, pde, vpgt->obj);
        }

        return 0;
}

int
nouveau_vm_get(struct nouveau_vm *vm, u64 size, u32 page_shift,
               u32 access, struct nouveau_vma *vma)
{
        u32 align = (1 << page_shift) >> 12;
        u32 msize = size >> 12;
        u32 fpde, lpde, pde;
        int ret;

        mutex_lock(&vm->mm->mutex);
        ret = nouveau_mm_get(vm->mm, page_shift, msize, 0, align, &vma->node);
        if (unlikely(ret != 0)) {
                mutex_unlock(&vm->mm->mutex);
                return ret;
        }

        fpde = (vma->node->offset >> vm->pgt_bits);
        lpde = (vma->node->offset + vma->node->length - 1) >> vm->pgt_bits;
        for (pde = fpde; pde <= lpde; pde++) {
                struct nouveau_vm_pgt *vpgt = &vm->pgt[pde - vm->fpde];
                int big = (vma->node->type != vm->spg_shift);

                if (likely(vpgt->refcount[big])) {
                        vpgt->refcount[big]++;
                        continue;
                }

                ret = nouveau_vm_map_pgt(vm, pde, vma->node->type);
                if (ret) {
                        if (pde != fpde)
                                nouveau_vm_unmap_pgt(vm, big, fpde, pde - 1);
                        nouveau_mm_put(vm->mm, vma->node);
                        mutex_unlock(&vm->mm->mutex);
                        vma->node = NULL;
                        return ret;
                }
        }
        mutex_unlock(&vm->mm->mutex);

        vma->vm     = vm;
        vma->offset = (u64)vma->node->offset << 12;
        vma->access = access;
        return 0;
}

void
nouveau_vm_put(struct nouveau_vma *vma)
{
        struct nouveau_vm *vm = vma->vm;
        u32 fpde, lpde;

        if (unlikely(vma->node == NULL))
                return;
        fpde = (vma->node->offset >> vm->pgt_bits);
        lpde = (vma->node->offset + vma->node->length - 1) >> vm->pgt_bits;

        mutex_lock(&vm->mm->mutex);
        nouveau_vm_unmap_pgt(vm, vma->node->type != vm->spg_shift, fpde, lpde);
        nouveau_mm_put(vm->mm, vma->node);
        vma->node = NULL;
        mutex_unlock(&vm->mm->mutex);
}

int
nouveau_vm_new(struct drm_device *dev, u64 offset, u64 length, u64 mm_offset,
               struct nouveau_vm **pvm)
{
        struct drm_nouveau_private *dev_priv = dev->dev_private;
        struct nouveau_vm *vm;
        u64 mm_length = (offset + length) - mm_offset;
        u32 block, pgt_bits;
        int ret;

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

        if (dev_priv->card_type == NV_50) {
                vm->map_pgt = nv50_vm_map_pgt;
                vm->map = nv50_vm_map;
                vm->map_sg = nv50_vm_map_sg;
                vm->unmap = nv50_vm_unmap;
                vm->flush = nv50_vm_flush;
                vm->spg_shift = 12;
                vm->lpg_shift = 16;

                pgt_bits = 29;
                block = (1 << pgt_bits);
                if (length < block)
                        block = length;

        } else
        if (dev_priv->card_type == NV_C0) {
                vm->map_pgt = nvc0_vm_map_pgt;
                vm->map = nvc0_vm_map;
                vm->map_sg = nvc0_vm_map_sg;
                vm->unmap = nvc0_vm_unmap;
                vm->flush = nvc0_vm_flush;
                vm->spg_shift = 12;
                vm->lpg_shift = 17;
                pgt_bits = 27;

                /* Should be 4096 everywhere, this is a hack that's
                 * currently necessary to avoid an elusive bug that
                 * causes corruption when mixing small/large pages
                 */
                if (length < (1ULL << 40))
                        block = 4096;
                else {
                        block = (1 << pgt_bits);
                        if (length < block)
                                block = length;
                }
        } else {
                kfree(vm);
                return -ENOSYS;
        }

        vm->fpde   = offset >> pgt_bits;
        vm->lpde   = (offset + length - 1) >> pgt_bits;
        vm->pgt = kcalloc(vm->lpde - vm->fpde + 1, sizeof(*vm->pgt), GFP_KERNEL);
        if (!vm->pgt) {
                kfree(vm);
                return -ENOMEM;
        }

        INIT_LIST_HEAD(&vm->pgd_list);
        vm->dev = dev;
        vm->refcount = 1;
        vm->pgt_bits = pgt_bits - 12;

        ret = nouveau_mm_init(&vm->mm, mm_offset >> 12, mm_length >> 12,
                              block >> 12);
        if (ret) {
                kfree(vm);
                return ret;
        }

        *pvm = vm;
        return 0;
}

static int
nouveau_vm_link(struct nouveau_vm *vm, struct nouveau_gpuobj *pgd)
{
        struct nouveau_vm_pgd *vpgd;
        int i;

        if (!pgd)
                return 0;

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

        nouveau_gpuobj_ref(pgd, &vpgd->obj);

        mutex_lock(&vm->mm->mutex);
        for (i = vm->fpde; i <= vm->lpde; i++)
                vm->map_pgt(pgd, i, vm->pgt[i - vm->fpde].obj);
        list_add(&vpgd->head, &vm->pgd_list);
        mutex_unlock(&vm->mm->mutex);
        return 0;
}

static void
nouveau_vm_unlink(struct nouveau_vm *vm, struct nouveau_gpuobj *pgd)
{
        struct nouveau_vm_pgd *vpgd, *tmp;

        if (!pgd)
                return;

        mutex_lock(&vm->mm->mutex);
        list_for_each_entry_safe(vpgd, tmp, &vm->pgd_list, head) {
                if (vpgd->obj != pgd)
                        continue;

                list_del(&vpgd->head);
                nouveau_gpuobj_ref(NULL, &vpgd->obj);
                kfree(vpgd);
        }
        mutex_unlock(&vm->mm->mutex);
}

static void
nouveau_vm_del(struct nouveau_vm *vm)
{
        struct nouveau_vm_pgd *vpgd, *tmp;

        list_for_each_entry_safe(vpgd, tmp, &vm->pgd_list, head) {
                nouveau_vm_unlink(vm, vpgd->obj);
        }
        WARN_ON(nouveau_mm_fini(&vm->mm) != 0);

        kfree(vm->pgt);
        kfree(vm);
}

int
nouveau_vm_ref(struct nouveau_vm *ref, struct nouveau_vm **ptr,
               struct nouveau_gpuobj *pgd)
{
        struct nouveau_vm *vm;
        int ret;

        vm = ref;
        if (vm) {
                ret = nouveau_vm_link(vm, pgd);
                if (ret)
                        return ret;

                vm->refcount++;
        }

        vm = *ptr;
        *ptr = ref;

        if (vm) {
                nouveau_vm_unlink(vm, pgd);

                if (--vm->refcount == 0)
                        nouveau_vm_del(vm);
        }

        return 0;
}