/* SPDX-License-Identifier: GPL-2.0 OR MIT */
/**************************************************************************
 *
 * Copyright (c) 2007-2009 VMware, Inc., Palo Alto, CA., USA
 * All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sub license, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice (including the
 * next paragraph) 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 NON-INFRINGEMENT. IN NO EVENT SHALL
 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 * USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 **************************************************************************/
/*
 * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
 */

#include <drm/ttm/ttm_bo_driver.h>
#include <drm/ttm/ttm_placement.h>
#include <drm/drm_cache.h>
#include <drm/drm_vma_manager.h>
#include <linux/dma-buf-map.h>
#include <linux/io.h>
#include <linux/highmem.h>
#include <linux/wait.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/module.h>
#include <linux/dma-resv.h>

struct ttm_transfer_obj {
        struct ttm_buffer_object base;
        struct ttm_buffer_object *bo;
};

int ttm_mem_io_reserve(struct ttm_device *bdev,
                       struct ttm_resource *mem)
{
        if (mem->bus.offset || mem->bus.addr)
                return 0;

        mem->bus.is_iomem = false;
        if (!bdev->funcs->io_mem_reserve)
                return 0;

        return bdev->funcs->io_mem_reserve(bdev, mem);
}

void ttm_mem_io_free(struct ttm_device *bdev,
                     struct ttm_resource *mem)
{
        if (!mem)
                return;

        if (!mem->bus.offset && !mem->bus.addr)
                return;

        if (bdev->funcs->io_mem_free)
                bdev->funcs->io_mem_free(bdev, mem);

        mem->bus.offset = 0;
        mem->bus.addr = NULL;
}

/**
 * ttm_move_memcpy - Helper to perform a memcpy ttm move operation.
 * @bo: The struct ttm_buffer_object.
 * @new_mem: The struct ttm_resource we're moving to (copy destination).
 * @new_iter: A struct ttm_kmap_iter representing the destination resource.
 * @src_iter: A struct ttm_kmap_iter representing the source resource.
 *
 * This function is intended to be able to move out async under a
 * dma-fence if desired.
 */
void ttm_move_memcpy(struct ttm_buffer_object *bo,
                     u32 num_pages,
                     struct ttm_kmap_iter *dst_iter,
                     struct ttm_kmap_iter *src_iter)
{
        const struct ttm_kmap_iter_ops *dst_ops = dst_iter->ops;
        const struct ttm_kmap_iter_ops *src_ops = src_iter->ops;
        struct ttm_tt *ttm = bo->ttm;
        struct dma_buf_map src_map, dst_map;
        pgoff_t i;

        /* Single TTM move. NOP */
        if (dst_ops->maps_tt && src_ops->maps_tt)
                return;

        /* Don't move nonexistent data. Clear destination instead. */
        if (src_ops->maps_tt && (!ttm || !ttm_tt_is_populated(ttm))) {
                if (ttm && !(ttm->page_flags & TTM_PAGE_FLAG_ZERO_ALLOC))
                        return;

                for (i = 0; i < num_pages; ++i) {
                        dst_ops->map_local(dst_iter, &dst_map, i);
                        if (dst_map.is_iomem)
                                memset_io(dst_map.vaddr_iomem, 0, PAGE_SIZE);
                        else
                                memset(dst_map.vaddr, 0, PAGE_SIZE);
                        if (dst_ops->unmap_local)
                                dst_ops->unmap_local(dst_iter, &dst_map);
                }
                return;
        }

        for (i = 0; i < num_pages; ++i) {
                dst_ops->map_local(dst_iter, &dst_map, i);
                src_ops->map_local(src_iter, &src_map, i);

                drm_memcpy_from_wc(&dst_map, &src_map, PAGE_SIZE);

                if (src_ops->unmap_local)
                        src_ops->unmap_local(src_iter, &src_map);
                if (dst_ops->unmap_local)
                        dst_ops->unmap_local(dst_iter, &dst_map);
        }
}
EXPORT_SYMBOL(ttm_move_memcpy);

int ttm_bo_move_memcpy(struct ttm_buffer_object *bo,
                       struct ttm_operation_ctx *ctx,
                       struct ttm_resource *dst_mem)
{
        struct ttm_device *bdev = bo->bdev;
        struct ttm_resource_manager *dst_man =
                ttm_manager_type(bo->bdev, dst_mem->mem_type);
        struct ttm_tt *ttm = bo->ttm;
        struct ttm_resource *src_mem = bo->resource;
        struct ttm_resource_manager *src_man =
                ttm_manager_type(bdev, src_mem->mem_type);
        union {
                struct ttm_kmap_iter_tt tt;
                struct ttm_kmap_iter_linear_io io;
        } _dst_iter, _src_iter;
        struct ttm_kmap_iter *dst_iter, *src_iter;
        int ret = 0;

        if (ttm && ((ttm->page_flags & TTM_PAGE_FLAG_SWAPPED) ||
                    dst_man->use_tt)) {
                ret = ttm_tt_populate(bdev, ttm, ctx);
                if (ret)
                        return ret;
        }

        dst_iter = ttm_kmap_iter_linear_io_init(&_dst_iter.io, bdev, dst_mem);
        if (PTR_ERR(dst_iter) == -EINVAL && dst_man->use_tt)
                dst_iter = ttm_kmap_iter_tt_init(&_dst_iter.tt, bo->ttm);
        if (IS_ERR(dst_iter))
                return PTR_ERR(dst_iter);

        src_iter = ttm_kmap_iter_linear_io_init(&_src_iter.io, bdev, src_mem);
        if (PTR_ERR(src_iter) == -EINVAL && src_man->use_tt)
                src_iter = ttm_kmap_iter_tt_init(&_src_iter.tt, bo->ttm);
        if (IS_ERR(src_iter)) {
                ret = PTR_ERR(src_iter);
                goto out_src_iter;
        }

        ttm_move_memcpy(bo, dst_mem->num_pages, dst_iter, src_iter);

        if (!src_iter->ops->maps_tt)
                ttm_kmap_iter_linear_io_fini(&_src_iter.io, bdev, src_mem);
        ttm_bo_move_sync_cleanup(bo, dst_mem);

out_src_iter:
        if (!dst_iter->ops->maps_tt)
                ttm_kmap_iter_linear_io_fini(&_dst_iter.io, bdev, dst_mem);

        return ret;
}
EXPORT_SYMBOL(ttm_bo_move_memcpy);

static void ttm_transfered_destroy(struct ttm_buffer_object *bo)
{
        struct ttm_transfer_obj *fbo;

        fbo = container_of(bo, struct ttm_transfer_obj, base);
        dma_resv_fini(&fbo->base.base._resv);
        ttm_bo_put(fbo->bo);
        kfree(fbo);
}

/**
 * ttm_buffer_object_transfer
 *
 * @bo: A pointer to a struct ttm_buffer_object.
 * @new_obj: A pointer to a pointer to a newly created ttm_buffer_object,
 * holding the data of @bo with the old placement.
 *
 * This is a utility function that may be called after an accelerated move
 * has been scheduled. A new buffer object is created as a placeholder for
 * the old data while it's being copied. When that buffer object is idle,
 * it can be destroyed, releasing the space of the old placement.
 * Returns:
 * !0: Failure.
 */

static int ttm_buffer_object_transfer(struct ttm_buffer_object *bo,
                                      struct ttm_buffer_object **new_obj)
{
        struct ttm_transfer_obj *fbo;
        int ret;

        fbo = kmalloc(sizeof(*fbo), GFP_KERNEL);
        if (!fbo)
                return -ENOMEM;

        fbo->base = *bo;

        ttm_bo_get(bo);
        fbo->bo = bo;

        /**
         * Fix up members that we shouldn't copy directly:
         * TODO: Explicit member copy would probably be better here.
         */

        atomic_inc(&ttm_glob.bo_count);
        INIT_LIST_HEAD(&fbo->base.ddestroy);
        INIT_LIST_HEAD(&fbo->base.lru);
        fbo->base.moving = NULL;
        drm_vma_node_reset(&fbo->base.base.vma_node);

        kref_init(&fbo->base.kref);
        fbo->base.destroy = &ttm_transfered_destroy;
        fbo->base.pin_count = 0;
        if (bo->type != ttm_bo_type_sg)
                fbo->base.base.resv = &fbo->base.base._resv;

        dma_resv_init(&fbo->base.base._resv);
        fbo->base.base.dev = NULL;
        ret = dma_resv_trylock(&fbo->base.base._resv);
        WARN_ON(!ret);

        ttm_bo_move_to_lru_tail_unlocked(&fbo->base);

        *new_obj = &fbo->base;
        return 0;
}

pgprot_t ttm_io_prot(struct ttm_buffer_object *bo, struct ttm_resource *res,
                     pgprot_t tmp)
{
        struct ttm_resource_manager *man;
        enum ttm_caching caching;

        man = ttm_manager_type(bo->bdev, res->mem_type);
        caching = man->use_tt ? bo->ttm->caching : res->bus.caching;

        return ttm_prot_from_caching(caching, tmp);
}
EXPORT_SYMBOL(ttm_io_prot);

static int ttm_bo_ioremap(struct ttm_buffer_object *bo,
                          unsigned long offset,
                          unsigned long size,
                          struct ttm_bo_kmap_obj *map)
{
        struct ttm_resource *mem = bo->resource;

        if (bo->resource->bus.addr) {
                map->bo_kmap_type = ttm_bo_map_premapped;
                map->virtual = ((u8 *)bo->resource->bus.addr) + offset;
        } else {
                resource_size_t res = bo->resource->bus.offset + offset;

                map->bo_kmap_type = ttm_bo_map_iomap;
                if (mem->bus.caching == ttm_write_combined)
                        map->virtual = ioremap_wc(res, size);
#ifdef CONFIG_X86
                else if (mem->bus.caching == ttm_cached)
                        map->virtual = ioremap_cache(res, size);
#endif
                else
                        map->virtual = ioremap(res, size);
        }
        return (!map->virtual) ? -ENOMEM : 0;
}

static int ttm_bo_kmap_ttm(struct ttm_buffer_object *bo,
                           unsigned long start_page,
                           unsigned long num_pages,
                           struct ttm_bo_kmap_obj *map)
{
        struct ttm_resource *mem = bo->resource;
        struct ttm_operation_ctx ctx = {
                .interruptible = false,
                .no_wait_gpu = false
        };
        struct ttm_tt *ttm = bo->ttm;
        pgprot_t prot;
        int ret;

        BUG_ON(!ttm);

        ret = ttm_tt_populate(bo->bdev, ttm, &ctx);
        if (ret)
                return ret;

        if (num_pages == 1 && ttm->caching == ttm_cached) {
                /*
                 * We're mapping a single page, and the desired
                 * page protection is consistent with the bo.
                 */

                map->bo_kmap_type = ttm_bo_map_kmap;
                map->page = ttm->pages[start_page];
                map->virtual = kmap(map->page);
        } else {
                /*
                 * We need to use vmap to get the desired page protection
                 * or to make the buffer object look contiguous.
                 */
                prot = ttm_io_prot(bo, mem, PAGE_KERNEL);
                map->bo_kmap_type = ttm_bo_map_vmap;
                map->virtual = vmap(ttm->pages + start_page, num_pages,
                                    0, prot);
        }
        return (!map->virtual) ? -ENOMEM : 0;
}

int ttm_bo_kmap(struct ttm_buffer_object *bo,
                unsigned long start_page, unsigned long num_pages,
                struct ttm_bo_kmap_obj *map)
{
        unsigned long offset, size;
        int ret;

        map->virtual = NULL;
        map->bo = bo;
        if (num_pages > bo->resource->num_pages)
                return -EINVAL;
        if ((start_page + num_pages) > bo->resource->num_pages)
                return -EINVAL;

        ret = ttm_mem_io_reserve(bo->bdev, bo->resource);
        if (ret)
                return ret;
        if (!bo->resource->bus.is_iomem) {
                return ttm_bo_kmap_ttm(bo, start_page, num_pages, map);
        } else {
                offset = start_page << PAGE_SHIFT;
                size = num_pages << PAGE_SHIFT;
                return ttm_bo_ioremap(bo, offset, size, map);
        }
}
EXPORT_SYMBOL(ttm_bo_kmap);

void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map)
{
        if (!map->virtual)
                return;
        switch (map->bo_kmap_type) {
        case ttm_bo_map_iomap:
                iounmap(map->virtual);
                break;
        case ttm_bo_map_vmap:
                vunmap(map->virtual);
                break;
        case ttm_bo_map_kmap:
                kunmap(map->page);
                break;
        case ttm_bo_map_premapped:
                break;
        default:
                BUG();
        }
        ttm_mem_io_free(map->bo->bdev, map->bo->resource);
        map->virtual = NULL;
        map->page = NULL;
}
EXPORT_SYMBOL(ttm_bo_kunmap);

int ttm_bo_vmap(struct ttm_buffer_object *bo, struct dma_buf_map *map)
{
        struct ttm_resource *mem = bo->resource;
        int ret;

        ret = ttm_mem_io_reserve(bo->bdev, mem);
        if (ret)
                return ret;

        if (mem->bus.is_iomem) {
                void __iomem *vaddr_iomem;

                if (mem->bus.addr)
                        vaddr_iomem = (void __iomem *)mem->bus.addr;
                else if (mem->bus.caching == ttm_write_combined)
                        vaddr_iomem = ioremap_wc(mem->bus.offset,
                                                 bo->base.size);
#ifdef CONFIG_X86
                else if (mem->bus.caching == ttm_cached)
                        vaddr_iomem = ioremap_cache(mem->bus.offset,
                                                  bo->base.size);
#endif
                else
                        vaddr_iomem = ioremap(mem->bus.offset, bo->base.size);

                if (!vaddr_iomem)
                        return -ENOMEM;

                dma_buf_map_set_vaddr_iomem(map, vaddr_iomem);

        } else {
                struct ttm_operation_ctx ctx = {
                        .interruptible = false,
                        .no_wait_gpu = false
                };
                struct ttm_tt *ttm = bo->ttm;
                pgprot_t prot;
                void *vaddr;

                ret = ttm_tt_populate(bo->bdev, ttm, &ctx);
                if (ret)
                        return ret;

                /*
                 * We need to use vmap to get the desired page protection
                 * or to make the buffer object look contiguous.
                 */
                prot = ttm_io_prot(bo, mem, PAGE_KERNEL);
                vaddr = vmap(ttm->pages, ttm->num_pages, 0, prot);
                if (!vaddr)
                        return -ENOMEM;

                dma_buf_map_set_vaddr(map, vaddr);
        }

        return 0;
}
EXPORT_SYMBOL(ttm_bo_vmap);

void ttm_bo_vunmap(struct ttm_buffer_object *bo, struct dma_buf_map *map)
{
        struct ttm_resource *mem = bo->resource;

        if (dma_buf_map_is_null(map))
                return;

        if (!map->is_iomem)
                vunmap(map->vaddr);
        else if (!mem->bus.addr)
                iounmap(map->vaddr_iomem);
        dma_buf_map_clear(map);

        ttm_mem_io_free(bo->bdev, bo->resource);
}
EXPORT_SYMBOL(ttm_bo_vunmap);

static int ttm_bo_wait_free_node(struct ttm_buffer_object *bo,
                                 bool dst_use_tt)
{
        int ret;
        ret = ttm_bo_wait(bo, false, false);
        if (ret)
                return ret;

        if (!dst_use_tt)
                ttm_bo_tt_destroy(bo);
        ttm_resource_free(bo, &bo->resource);
        return 0;
}

static int ttm_bo_move_to_ghost(struct ttm_buffer_object *bo,
                                struct dma_fence *fence,
                                bool dst_use_tt)
{
        struct ttm_buffer_object *ghost_obj;
        int ret;

        /**
         * This should help pipeline ordinary buffer moves.
         *
         * Hang old buffer memory on a new buffer object,
         * and leave it to be released when the GPU
         * operation has completed.
         */

        dma_fence_put(bo->moving);
        bo->moving = dma_fence_get(fence);

        ret = ttm_buffer_object_transfer(bo, &ghost_obj);
        if (ret)
                return ret;

        dma_resv_add_excl_fence(&ghost_obj->base._resv, fence);

        /**
         * If we're not moving to fixed memory, the TTM object
         * needs to stay alive. Otherwhise hang it on the ghost
         * bo to be unbound and destroyed.
         */

        if (dst_use_tt)
                ghost_obj->ttm = NULL;
        else
                bo->ttm = NULL;
        bo->resource = NULL;

        dma_resv_unlock(&ghost_obj->base._resv);
        ttm_bo_put(ghost_obj);
        return 0;
}

static void ttm_bo_move_pipeline_evict(struct ttm_buffer_object *bo,
                                       struct dma_fence *fence)
{
        struct ttm_device *bdev = bo->bdev;
        struct ttm_resource_manager *from;

        from = ttm_manager_type(bdev, bo->resource->mem_type);

        /**
         * BO doesn't have a TTM we need to bind/unbind. Just remember
         * this eviction and free up the allocation
         */
        spin_lock(&from->move_lock);
        if (!from->move || dma_fence_is_later(fence, from->move)) {
                dma_fence_put(from->move);
                from->move = dma_fence_get(fence);
        }
        spin_unlock(&from->move_lock);

        ttm_resource_free(bo, &bo->resource);

        dma_fence_put(bo->moving);
        bo->moving = dma_fence_get(fence);
}

int ttm_bo_move_accel_cleanup(struct ttm_buffer_object *bo,
                              struct dma_fence *fence,
                              bool evict,
                              bool pipeline,
                              struct ttm_resource *new_mem)
{
        struct ttm_device *bdev = bo->bdev;
        struct ttm_resource_manager *from = ttm_manager_type(bdev, bo->resource->mem_type);
        struct ttm_resource_manager *man = ttm_manager_type(bdev, new_mem->mem_type);
        int ret = 0;

        dma_resv_add_excl_fence(bo->base.resv, fence);
        if (!evict)
                ret = ttm_bo_move_to_ghost(bo, fence, man->use_tt);
        else if (!from->use_tt && pipeline)
                ttm_bo_move_pipeline_evict(bo, fence);
        else
                ret = ttm_bo_wait_free_node(bo, man->use_tt);

        if (ret)
                return ret;

        ttm_bo_assign_mem(bo, new_mem);

        return 0;
}
EXPORT_SYMBOL(ttm_bo_move_accel_cleanup);

/**
 * ttm_bo_pipeline_gutting - purge the contents of a bo
 * @bo: The buffer object
 *
 * Purge the contents of a bo, async if the bo is not idle.
 * After a successful call, the bo is left unpopulated in
 * system placement. The function may wait uninterruptible
 * for idle on OOM.
 *
 * Return: 0 if successful, negative error code on failure.
 */
int ttm_bo_pipeline_gutting(struct ttm_buffer_object *bo)
{
        static const struct ttm_place sys_mem = { .mem_type = TTM_PL_SYSTEM };
        struct ttm_buffer_object *ghost;
        struct ttm_resource *sys_res;
        struct ttm_tt *ttm;
        int ret;

        ret = ttm_resource_alloc(bo, &sys_mem, &sys_res);
        if (ret)
                return ret;

        /* If already idle, no need for ghost object dance. */
        ret = ttm_bo_wait(bo, false, true);
        if (ret != -EBUSY) {
                if (!bo->ttm) {
                        /* See comment below about clearing. */
                        ret = ttm_tt_create(bo, true);
                        if (ret)
                                goto error_free_sys_mem;
                } else {
                        ttm_tt_unpopulate(bo->bdev, bo->ttm);
                        if (bo->type == ttm_bo_type_device)
                                ttm_tt_mark_for_clear(bo->ttm);
                }
                ttm_resource_free(bo, &bo->resource);
                ttm_bo_assign_mem(bo, sys_res);
                return 0;
        }

        /*
         * We need an unpopulated ttm_tt after giving our current one,
         * if any, to the ghost object. And we can't afford to fail
         * creating one *after* the operation. If the bo subsequently gets
         * resurrected, make sure it's cleared (if ttm_bo_type_device)
         * to avoid leaking sensitive information to user-space.
         */

        ttm = bo->ttm;
        bo->ttm = NULL;
        ret = ttm_tt_create(bo, true);
        swap(bo->ttm, ttm);
        if (ret)
                goto error_free_sys_mem;

        ret = ttm_buffer_object_transfer(bo, &ghost);
        if (ret)
                goto error_destroy_tt;

        ret = dma_resv_copy_fences(&ghost->base._resv, bo->base.resv);
        /* Last resort, wait for the BO to be idle when we are OOM */
        if (ret)
                ttm_bo_wait(bo, false, false);

        dma_resv_unlock(&ghost->base._resv);
        ttm_bo_put(ghost);
        bo->ttm = ttm;
        bo->resource = NULL;
        ttm_bo_assign_mem(bo, sys_res);
        return 0;

error_destroy_tt:
        ttm_tt_destroy(bo->bdev, ttm);

error_free_sys_mem:
        ttm_resource_free(bo, &sys_res);
        return ret;
}