/*
 * 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 <linux/dma-mapping.h>
#include <linux/moduleparam.h>

#include "virtgpu_drv.h"

static int virtio_gpu_virglrenderer_workaround = 1;
module_param_named(virglhack, virtio_gpu_virglrenderer_workaround, int, 0400);

static int virtio_gpu_resource_id_get(struct virtio_gpu_device *vgdev,
                                       uint32_t *resid)
{
        if (virtio_gpu_virglrenderer_workaround) {
                /*
                 * Hack to avoid re-using resource IDs.
                 *
                 * virglrenderer versions up to (and including) 0.7.0
                 * can't deal with that.  virglrenderer commit
                 * "f91a9dd35715 Fix unlinking resources from hash
                 * table." (Feb 2019) fixes the bug.
                 */
                static atomic_t seqno = ATOMIC_INIT(0);
                int handle = atomic_inc_return(&seqno);
                *resid = handle + 1;
        } else {
                int handle = ida_alloc(&vgdev->resource_ida, GFP_KERNEL);
                if (handle < 0)
                        return handle;
                *resid = handle + 1;
        }
        return 0;
}

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

void virtio_gpu_cleanup_object(struct virtio_gpu_object *bo)
{
        struct virtio_gpu_device *vgdev = bo->base.base.dev->dev_private;

        virtio_gpu_resource_id_put(vgdev, bo->hw_res_handle);
        if (virtio_gpu_is_shmem(bo)) {
                struct virtio_gpu_object_shmem *shmem = to_virtio_gpu_shmem(bo);

                if (shmem->pages) {
                        if (shmem->mapped) {
                                dma_unmap_sgtable(vgdev->vdev->dev.parent,
                                             shmem->pages, DMA_TO_DEVICE, 0);
                                shmem->mapped = 0;
                        }

                        sg_free_table(shmem->pages);
                        kfree(shmem->pages);
                        shmem->pages = NULL;
                        drm_gem_shmem_unpin(&bo->base.base);
                }

                drm_gem_shmem_free_object(&bo->base.base);
        }
}

static void virtio_gpu_free_object(struct drm_gem_object *obj)
{
        struct virtio_gpu_object *bo = gem_to_virtio_gpu_obj(obj);
        struct virtio_gpu_device *vgdev = bo->base.base.dev->dev_private;

        if (bo->created) {
                virtio_gpu_cmd_unref_resource(vgdev, bo);
                virtio_gpu_notify(vgdev);
                /* completion handler calls virtio_gpu_cleanup_object() */
                return;
        }
        virtio_gpu_cleanup_object(bo);
}

static const struct drm_gem_object_funcs virtio_gpu_shmem_funcs = {
        .free = virtio_gpu_free_object,
        .open = virtio_gpu_gem_object_open,
        .close = virtio_gpu_gem_object_close,

        .print_info = drm_gem_shmem_print_info,
        .pin = drm_gem_shmem_pin,
        .unpin = drm_gem_shmem_unpin,
        .get_sg_table = drm_gem_shmem_get_sg_table,
        .vmap = drm_gem_shmem_vmap,
        .vunmap = drm_gem_shmem_vunmap,
        .mmap = drm_gem_shmem_mmap,
};

bool virtio_gpu_is_shmem(struct virtio_gpu_object *bo)
{
        return bo->base.base.funcs == &virtio_gpu_shmem_funcs;
}

struct drm_gem_object *virtio_gpu_create_object(struct drm_device *dev,
                                                size_t size)
{
        struct virtio_gpu_object_shmem *shmem;
        struct drm_gem_shmem_object *dshmem;

        shmem = kzalloc(sizeof(*shmem), GFP_KERNEL);
        if (!shmem)
                return NULL;

        dshmem = &shmem->base.base;
        dshmem->base.funcs = &virtio_gpu_shmem_funcs;
        dshmem->map_cached = true;
        return &dshmem->base;
}

static int virtio_gpu_object_shmem_init(struct virtio_gpu_device *vgdev,
                                        struct virtio_gpu_object *bo,
                                        struct virtio_gpu_mem_entry **ents,
                                        unsigned int *nents)
{
        bool use_dma_api = !virtio_has_dma_quirk(vgdev->vdev);
        struct virtio_gpu_object_shmem *shmem = to_virtio_gpu_shmem(bo);
        struct scatterlist *sg;
        int si, ret;

        ret = drm_gem_shmem_pin(&bo->base.base);
        if (ret < 0)
                return -EINVAL;

        /*
         * virtio_gpu uses drm_gem_shmem_get_sg_table instead of
         * drm_gem_shmem_get_pages_sgt because virtio has it's own set of
         * dma-ops. This is discouraged for other drivers, but should be fine
         * since virtio_gpu doesn't support dma-buf import from other devices.
         */
        shmem->pages = drm_gem_shmem_get_sg_table(&bo->base.base);
        if (!shmem->pages) {
                drm_gem_shmem_unpin(&bo->base.base);
                return -EINVAL;
        }

        if (use_dma_api) {
                ret = dma_map_sgtable(vgdev->vdev->dev.parent,
                                      shmem->pages, DMA_TO_DEVICE, 0);
                if (ret)
                        return ret;
                *nents = shmem->mapped = shmem->pages->nents;
        } else {
                *nents = shmem->pages->orig_nents;
        }

        *ents = kmalloc_array(*nents, sizeof(struct virtio_gpu_mem_entry),
                              GFP_KERNEL);
        if (!(*ents)) {
                DRM_ERROR("failed to allocate ent list\n");
                return -ENOMEM;
        }

        if (use_dma_api) {
                for_each_sgtable_dma_sg(shmem->pages, sg, si) {
                        (*ents)[si].addr = cpu_to_le64(sg_dma_address(sg));
                        (*ents)[si].length = cpu_to_le32(sg_dma_len(sg));
                        (*ents)[si].padding = 0;
                }
        } else {
                for_each_sgtable_sg(shmem->pages, sg, si) {
                        (*ents)[si].addr = cpu_to_le64(sg_phys(sg));
                        (*ents)[si].length = cpu_to_le32(sg->length);
                        (*ents)[si].padding = 0;
                }
        }

        return 0;
}

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_array *objs = NULL;
        struct drm_gem_shmem_object *shmem_obj;
        struct virtio_gpu_object *bo;
        struct virtio_gpu_mem_entry *ents;
        unsigned int nents;
        int ret;

        *bo_ptr = NULL;

        params->size = roundup(params->size, PAGE_SIZE);
        shmem_obj = drm_gem_shmem_create(vgdev->ddev, params->size);
        if (IS_ERR(shmem_obj))
                return PTR_ERR(shmem_obj);
        bo = gem_to_virtio_gpu_obj(&shmem_obj->base);

        ret = virtio_gpu_resource_id_get(vgdev, &bo->hw_res_handle);
        if (ret < 0)
                goto err_free_gem;

        bo->dumb = params->dumb;

        if (fence) {
                ret = -ENOMEM;
                objs = virtio_gpu_array_alloc(1);
                if (!objs)
                        goto err_put_id;
                virtio_gpu_array_add_obj(objs, &bo->base.base);

                ret = virtio_gpu_array_lock_resv(objs);
                if (ret != 0)
                        goto err_put_objs;
        }

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

        ret = virtio_gpu_object_shmem_init(vgdev, bo, &ents, &nents);
        if (ret != 0) {
                virtio_gpu_free_object(&shmem_obj->base);
                return ret;
        }

        virtio_gpu_object_attach(vgdev, bo, ents, nents);

        *bo_ptr = bo;
        return 0;

err_put_objs:
        virtio_gpu_array_put_free(objs);
err_put_id:
        virtio_gpu_resource_id_put(vgdev, bo->hw_res_handle);
err_free_gem:
        drm_gem_shmem_free_object(&shmem_obj->base);
        return ret;
}