/*
 * Copyright (C) 2015 Red Hat, Inc.
 * All Rights Reserved.
 *
 * Authors:
 *    Dave Airlie
 *    Alon Levy
 *
 * 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.
 */

#include <linux/delay.h>

#include <drm/drm.h>
#include <drm/drm_file.h>
#include <drm/ttm/ttm_bo_api.h>
#include <drm/ttm/ttm_bo_driver.h>
#include <drm/ttm/ttm_module.h>
#include <drm/ttm/ttm_page_alloc.h>
#include <drm/ttm/ttm_placement.h>
#include <drm/virtgpu_drm.h>

#include "virtgpu_drv.h"

static struct
virtio_gpu_device *virtio_gpu_get_vgdev(struct ttm_bo_device *bdev)
{
	struct virtio_gpu_mman *mman;
	struct virtio_gpu_device *vgdev;

	mman = container_of(bdev, struct virtio_gpu_mman, bdev);
	vgdev = container_of(mman, struct virtio_gpu_device, mman);
	return vgdev;
}

int virtio_gpu_mmap(struct file *filp, struct vm_area_struct *vma)
{
	struct drm_file *file_priv;
	struct virtio_gpu_device *vgdev;
	int r;

	file_priv = filp->private_data;
	vgdev = file_priv->minor->dev->dev_private;
	if (vgdev == NULL) {
		DRM_ERROR(
		 "filp->private_data->minor->dev->dev_private == NULL\n");
		return -EINVAL;
	}
	r = ttm_bo_mmap(filp, vma, &vgdev->mman.bdev);

	return r;
}

static int virtio_gpu_invalidate_caches(struct ttm_bo_device *bdev,
					uint32_t flags)
{
	return 0;
}

static int ttm_bo_man_get_node(struct ttm_mem_type_manager *man,
			       struct ttm_buffer_object *bo,
			       const struct ttm_place *place,
			       struct ttm_mem_reg *mem)
{
	mem->mm_node = (void *)1;
	return 0;
}

static void ttm_bo_man_put_node(struct ttm_mem_type_manager *man,
				struct ttm_mem_reg *mem)
{
	mem->mm_node = (void *)NULL;
}

static int ttm_bo_man_init(struct ttm_mem_type_manager *man,
			   unsigned long p_size)
{
	return 0;
}

static int ttm_bo_man_takedown(struct ttm_mem_type_manager *man)
{
	return 0;
}

static void ttm_bo_man_debug(struct ttm_mem_type_manager *man,
			     struct drm_printer *printer)
{
}

static const struct ttm_mem_type_manager_func virtio_gpu_bo_manager_func = {
	.init = ttm_bo_man_init,
	.takedown = ttm_bo_man_takedown,
	.get_node = ttm_bo_man_get_node,
	.put_node = ttm_bo_man_put_node,
	.debug = ttm_bo_man_debug
};

static int virtio_gpu_init_mem_type(struct ttm_bo_device *bdev, uint32_t type,
				    struct ttm_mem_type_manager *man)
{
	switch (type) {
	case TTM_PL_SYSTEM:
		/* System memory */
		man->flags = TTM_MEMTYPE_FLAG_MAPPABLE;
		man->available_caching = TTM_PL_MASK_CACHING;
		man->default_caching = TTM_PL_FLAG_CACHED;
		break;
	case TTM_PL_TT:
		man->func = &virtio_gpu_bo_manager_func;
		man->flags = TTM_MEMTYPE_FLAG_MAPPABLE;
		man->available_caching = TTM_PL_MASK_CACHING;
		man->default_caching = TTM_PL_FLAG_CACHED;
		break;
	case TTM_PL_VRAM:
		man->func = &ttm_bo_manager_func;
		man->flags = TTM_MEMTYPE_FLAG_MAPPABLE;
		man->available_caching = TTM_PL_MASK_CACHING;
		man->default_caching = TTM_PL_FLAG_CACHED;
		break;
	default:
		DRM_ERROR("Unsupported memory type %u\n", (unsigned int)type);
		return -EINVAL;
	}
	return 0;
}

static void virtio_gpu_evict_flags(struct ttm_buffer_object *bo,
				struct ttm_placement *placement)
{
	static const struct ttm_place placements = {
		.fpfn  = 0,
		.lpfn  = 0,
		.flags = TTM_PL_MASK_CACHING | TTM_PL_FLAG_SYSTEM,
	};

	placement->placement = &placements;
	placement->busy_placement = &placements;
	placement->num_placement = 1;
	placement->num_busy_placement = 1;
}

static int virtio_gpu_verify_access(struct ttm_buffer_object *bo,
				    struct file *filp)
{
	return 0;
}

static int virtio_gpu_ttm_io_mem_reserve(struct ttm_bo_device *bdev,
					 struct ttm_mem_reg *mem)
{
	struct virtio_gpu_device *vgdev = virtio_gpu_get_vgdev(bdev);
	struct ttm_mem_type_manager *man = &bdev->man[mem->mem_type];

	mem->bus.addr = NULL;
	mem->bus.offset = 0;
	mem->bus.size = mem->num_pages << PAGE_SHIFT;
	mem->bus.base = 0;
	mem->bus.is_iomem = false;
	if (!(man->flags & TTM_MEMTYPE_FLAG_MAPPABLE))
		return -EINVAL;
	switch (mem->mem_type) {
	case TTM_PL_SYSTEM:
	case TTM_PL_TT:
		/* system memory */
		mem->bus.offset = 0;
		mem->bus.base = 0;
		mem->bus.is_iomem = false;
		return 0;
	case TTM_PL_VRAM:
		/* coherent memory (pci bar) */
		mem->bus.offset = mem->start << PAGE_SHIFT;
		mem->bus.base = vgdev->caddr;
		mem->bus.is_iomem = true;
		return 0;
	default:
		DRM_ERROR("Unsupported memory type %u\n", mem->mem_type);
		return -EINVAL;
	}
	return 0;
}

static void virtio_gpu_ttm_io_mem_free(struct ttm_bo_device *bdev,
				       struct ttm_mem_reg *mem)
{
}

/*
 * TTM backend functions.
 */
struct virtio_gpu_ttm_tt {
	struct ttm_dma_tt		ttm;
	struct virtio_gpu_object        *obj;
};

static int virtio_gpu_ttm_vram_bind(struct ttm_tt *ttm,
				    struct ttm_mem_reg *bo_mem)
{
	return 0;
}

static int virtio_gpu_ttm_vram_unbind(struct ttm_tt *ttm)
{
	struct virtio_gpu_ttm_tt *gtt =
		container_of(ttm, struct virtio_gpu_ttm_tt, ttm.ttm);
	struct virtio_gpu_device *vgdev =
		virtio_gpu_get_vgdev(gtt->obj->tbo.bdev);
	struct virtio_gpu_object *obj = gtt->obj;

	virtio_gpu_cmd_unmap(vgdev, obj->hw_res_handle);
	return 0;
}

static int virtio_gpu_ttm_tt_bind(struct ttm_tt *ttm,
				  struct ttm_mem_reg *bo_mem)
{
	struct virtio_gpu_ttm_tt *gtt =
		container_of(ttm, struct virtio_gpu_ttm_tt, ttm.ttm);
	struct virtio_gpu_device *vgdev =
		virtio_gpu_get_vgdev(gtt->obj->tbo.bdev);

	virtio_gpu_object_attach(vgdev, gtt->obj, NULL);
	return 0;
}

static int virtio_gpu_ttm_tt_unbind(struct ttm_tt *ttm)
{
	struct virtio_gpu_ttm_tt *gtt =
		container_of(ttm, struct virtio_gpu_ttm_tt, ttm.ttm);
	struct virtio_gpu_device *vgdev =
		virtio_gpu_get_vgdev(gtt->obj->tbo.bdev);

	virtio_gpu_object_detach(vgdev, gtt->obj);
	return 0;
}

static void virtio_gpu_ttm_tt_destroy(struct ttm_tt *ttm)
{
	struct virtio_gpu_ttm_tt *gtt =
		container_of(ttm, struct virtio_gpu_ttm_tt, ttm.ttm);

	ttm_dma_tt_fini(&gtt->ttm);
	kfree(gtt);
}

static struct ttm_backend_func virtio_gpu_tt_func = {
	.bind = &virtio_gpu_ttm_tt_bind,
	.unbind = &virtio_gpu_ttm_tt_unbind,
	.destroy = &virtio_gpu_ttm_tt_destroy,
};

static struct ttm_backend_func virtio_gpu_vram_func = {
	.bind = &virtio_gpu_ttm_vram_bind,
	.unbind = &virtio_gpu_ttm_vram_unbind,
	.destroy = &virtio_gpu_ttm_tt_destroy,
};

static struct ttm_tt *virtio_gpu_ttm_tt_create(struct ttm_buffer_object *bo,
					       uint32_t page_flags)
{
	struct virtio_gpu_device *vgdev;
	struct virtio_gpu_object *obj;
	struct virtio_gpu_ttm_tt *gtt;
	uint32_t has_guest;

	vgdev = virtio_gpu_get_vgdev(bo->bdev);
	obj = container_of(bo, struct virtio_gpu_object, tbo);

	gtt = kzalloc(sizeof(struct virtio_gpu_ttm_tt), GFP_KERNEL);
	if (gtt == NULL)
		return NULL;
	gtt->obj = obj;
	has_guest = (obj->blob_mem == VIRTGPU_BLOB_MEM_GUEST ||
	             obj->blob_mem == VIRTGPU_BLOB_MEM_HOST_GUEST);
	if (!has_guest && obj->blob) {
		gtt->ttm.ttm.func = &virtio_gpu_vram_func;
		if (ttm_tt_init(&gtt->ttm.ttm, bo, page_flags)) {
			kfree(gtt);
			return NULL;
		}
	} else {
		gtt->ttm.ttm.func = &virtio_gpu_tt_func;
		if (ttm_dma_tt_init(&gtt->ttm, bo, page_flags)) {
			kfree(gtt);
			return NULL;
		}
	}

	return &gtt->ttm.ttm;
}

static void virtio_gpu_bo_swap_notify(struct ttm_buffer_object *tbo)
{
	struct virtio_gpu_object *bo;

	bo = container_of(tbo, struct virtio_gpu_object, tbo);

	if (bo->pages)
		virtio_gpu_object_free_sg_table(bo);
}

static struct ttm_bo_driver virtio_gpu_bo_driver = {
	.ttm_tt_create = &virtio_gpu_ttm_tt_create,
	.invalidate_caches = &virtio_gpu_invalidate_caches,
	.init_mem_type = &virtio_gpu_init_mem_type,
	.eviction_valuable = ttm_bo_eviction_valuable,
	.evict_flags = &virtio_gpu_evict_flags,
	.verify_access = &virtio_gpu_verify_access,
	.io_mem_reserve = &virtio_gpu_ttm_io_mem_reserve,
	.io_mem_free = &virtio_gpu_ttm_io_mem_free,
	.swap_notify = &virtio_gpu_bo_swap_notify,
};

int virtio_gpu_ttm_init(struct virtio_gpu_device *vgdev)
{
	int r;

	/* No others user of address space so set it to 0 */
	r = ttm_bo_device_init(&vgdev->mman.bdev,
			       &virtio_gpu_bo_driver,
			       vgdev->ddev->anon_inode->i_mapping,
			       false);
	if (r) {
		DRM_ERROR("failed initializing buffer object driver(%d).\n", r);
		goto err_dev_init;
	}

	r = ttm_bo_init_mm(&vgdev->mman.bdev, TTM_PL_TT, 0);
	if (r) {
		DRM_ERROR("Failed initializing GTT heap.\n");
		goto err_mm_init;
	}

	if (vgdev->has_host_visible) {
		r = ttm_bo_init_mm(&vgdev->mman.bdev, TTM_PL_VRAM,
				   vgdev->csize >> PAGE_SHIFT);
		if (r) {
			DRM_ERROR("Failed initializing VRAM heap.\n");
			goto err_mm_init;
		}
	}
	return 0;

err_mm_init:
	ttm_bo_device_release(&vgdev->mman.bdev);
err_dev_init:
	return r;
}

void virtio_gpu_ttm_fini(struct virtio_gpu_device *vgdev)
{
	ttm_bo_device_release(&vgdev->mman.bdev);
	DRM_INFO("virtio_gpu: ttm finalized\n");
}