/*
 * Copyright (C) 2015 Red Hat, Inc.
 * 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, 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 (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 NONINFRINGEMENT.
 * IN NO EVENT SHALL THE COPYRIGHT OWNER(S) 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.
 */

#include <drm/ttm/ttm_execbuf_util.h>

#include "virtgpu_drv.h"

static int virtio_gpu_resource_id_get(struct virtio_gpu_device *vgdev,
                                       uint32_t *resid)
{
#if 0
        int handle = ida_alloc(&vgdev->resource_ida, GFP_KERNEL);

        if (handle < 0)
                return handle;
#else
        static int handle;

        /*
         * FIXME: dirty hack to avoid re-using IDs, virglrenderer
         * can't deal with that.  Needs fixing in virglrenderer, also
         * should figure a better way to handle that in the guest.
         */
        handle++;
#endif

        *resid = handle + 1;
        return 0;
}

static void virtio_gpu_resource_id_put(struct virtio_gpu_device *vgdev, uint32_t id)
{
#if 0
        ida_free(&vgdev->resource_ida, id - 1);
#endif
}

static void virtio_gpu_ttm_bo_destroy(struct ttm_buffer_object *tbo)
{
        struct virtio_gpu_object *bo;
        struct virtio_gpu_device *vgdev;

        bo = container_of(tbo, struct virtio_gpu_object, tbo);
        vgdev = (struct virtio_gpu_device *)bo->gem_base.dev->dev_private;

        if (bo->created)
                virtio_gpu_cmd_unref_resource(vgdev, bo->hw_res_handle);
        if (bo->pages)
                virtio_gpu_object_free_sg_table(bo);
        if (bo->vmap)
                virtio_gpu_object_kunmap(bo);
        drm_gem_object_release(&bo->gem_base);
        virtio_gpu_resource_id_put(vgdev, bo->hw_res_handle);
        kfree(bo);
}

static void virtio_gpu_init_ttm_placement(struct virtio_gpu_object *vgbo)
{
        u32 c = 1;

        vgbo->placement.placement = &vgbo->placement_code;
        vgbo->placement.busy_placement = &vgbo->placement_code;
        vgbo->placement_code.fpfn = 0;
        vgbo->placement_code.lpfn = 0;
        vgbo->placement_code.flags =
                TTM_PL_MASK_CACHING | TTM_PL_FLAG_TT |
                TTM_PL_FLAG_NO_EVICT;
        vgbo->placement.num_placement = c;
        vgbo->placement.num_busy_placement = c;

}

int virtio_gpu_object_create(struct virtio_gpu_device *vgdev,
                             struct virtio_gpu_object_params *params,
                             struct virtio_gpu_object **bo_ptr,
                             struct virtio_gpu_fence *fence)
{
        struct virtio_gpu_object *bo;
        size_t acc_size;
        int ret;

        *bo_ptr = NULL;

        acc_size = ttm_bo_dma_acc_size(&vgdev->mman.bdev, params->size,
                                       sizeof(struct virtio_gpu_object));

        bo = kzalloc(sizeof(struct virtio_gpu_object), GFP_KERNEL);
        if (bo == NULL)
                return -ENOMEM;
        ret = virtio_gpu_resource_id_get(vgdev, &bo->hw_res_handle);
        if (ret < 0) {
                kfree(bo);
                return ret;
        }
        params->size = roundup(params->size, PAGE_SIZE);
        ret = drm_gem_object_init(vgdev->ddev, &bo->gem_base, params->size);
        if (ret != 0) {
                virtio_gpu_resource_id_put(vgdev, bo->hw_res_handle);
                kfree(bo);
                return ret;
        }
        bo->dumb = params->dumb;

        if (params->virgl) {
                virtio_gpu_cmd_resource_create_3d(vgdev, bo, params, fence);
        } else {
                virtio_gpu_cmd_create_resource(vgdev, bo, params, fence);
        }

        virtio_gpu_init_ttm_placement(bo);
        ret = ttm_bo_init(&vgdev->mman.bdev, &bo->tbo, params->size,
                          ttm_bo_type_device, &bo->placement, 0,
                          true, acc_size, NULL, NULL,
                          &virtio_gpu_ttm_bo_destroy);
        /* ttm_bo_init failure will call the destroy */
        if (ret != 0)
                return ret;

        if (fence) {
                struct virtio_gpu_fence_driver *drv = &vgdev->fence_drv;
                struct list_head validate_list;
                struct ttm_validate_buffer mainbuf;
                struct ww_acquire_ctx ticket;
                unsigned long irq_flags;
                bool signaled;

                INIT_LIST_HEAD(&validate_list);
                memset(&mainbuf, 0, sizeof(struct ttm_validate_buffer));

                /* use a gem reference since unref list undoes them */
                drm_gem_object_get(&bo->gem_base);
                mainbuf.bo = &bo->tbo;
                list_add(&mainbuf.head, &validate_list);

                ret = virtio_gpu_object_list_validate(&ticket, &validate_list);
                if (ret == 0) {
                        spin_lock_irqsave(&drv->lock, irq_flags);
                        signaled = virtio_fence_signaled(&fence->f);
                        if (!signaled)
                                /* virtio create command still in flight */
                                ttm_eu_fence_buffer_objects(&ticket, &validate_list,
                                                            &fence->f);
                        spin_unlock_irqrestore(&drv->lock, irq_flags);
                        if (signaled)
                                /* virtio create command finished */
                                ttm_eu_backoff_reservation(&ticket, &validate_list);
                }
                virtio_gpu_unref_list(&validate_list);
        }

        *bo_ptr = bo;
        return 0;
}

void virtio_gpu_object_kunmap(struct virtio_gpu_object *bo)
{
        bo->vmap = NULL;
        ttm_bo_kunmap(&bo->kmap);
}

int virtio_gpu_object_kmap(struct virtio_gpu_object *bo)
{
        bool is_iomem;
        int r;

        WARN_ON(bo->vmap);

        r = ttm_bo_kmap(&bo->tbo, 0, bo->tbo.num_pages, &bo->kmap);
        if (r)
                return r;
        bo->vmap = ttm_kmap_obj_virtual(&bo->kmap, &is_iomem);
        return 0;
}

int virtio_gpu_object_get_sg_table(struct virtio_gpu_device *qdev,
                                   struct virtio_gpu_object *bo)
{
        int ret;
        struct page **pages = bo->tbo.ttm->pages;
        int nr_pages = bo->tbo.num_pages;
        struct ttm_operation_ctx ctx = {
                .interruptible = false,
                .no_wait_gpu = false
        };
        size_t max_segment;

        /* wtf swapping */
        if (bo->pages)
                return 0;

        if (bo->tbo.ttm->state == tt_unpopulated)
                bo->tbo.ttm->bdev->driver->ttm_tt_populate(bo->tbo.ttm, &ctx);
        bo->pages = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
        if (!bo->pages)
                goto out;

        max_segment = virtio_max_dma_size(qdev->vdev);
        max_segment &= PAGE_MASK;
        if (max_segment > SCATTERLIST_MAX_SEGMENT)
                max_segment = SCATTERLIST_MAX_SEGMENT;
        ret = __sg_alloc_table_from_pages(bo->pages, pages, nr_pages, 0,
                                          nr_pages << PAGE_SHIFT,
                                          max_segment, GFP_KERNEL);
        if (ret)
                goto out;
        return 0;
out:
        kfree(bo->pages);
        bo->pages = NULL;
        return -ENOMEM;
}

void virtio_gpu_object_free_sg_table(struct virtio_gpu_object *bo)
{
        sg_free_table(bo->pages);
        kfree(bo->pages);
        bo->pages = NULL;
}

int virtio_gpu_object_wait(struct virtio_gpu_object *bo, bool no_wait)
{
        int r;

        r = ttm_bo_reserve(&bo->tbo, true, no_wait, NULL);
        if (unlikely(r != 0))
                return r;
        r = ttm_bo_wait(&bo->tbo, true, no_wait);
        ttm_bo_unreserve(&bo->tbo);
        return r;
}