/*
 * 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/virtio.h>
#include <linux/virtio_config.h>
#include <drm/drmP.h>
#include "virtgpu_drv.h"

static int virtio_gpu_fbdev = 1;

MODULE_PARM_DESC(fbdev, "Disable/Enable framebuffer device & console");
module_param_named(fbdev, virtio_gpu_fbdev, int, 0400);

static void virtio_gpu_config_changed_work_func(struct work_struct *work)
{
	struct virtio_gpu_device *vgdev =
		container_of(work, struct virtio_gpu_device,
			     config_changed_work);
	u32 events_read, events_clear = 0;

	/* read the config space */
	virtio_cread(vgdev->vdev, struct virtio_gpu_config,
		     events_read, &events_read);
	if (events_read & VIRTIO_GPU_EVENT_DISPLAY) {
		virtio_gpu_cmd_get_display_info(vgdev);
		drm_helper_hpd_irq_event(vgdev->ddev);
		events_clear |= VIRTIO_GPU_EVENT_DISPLAY;
	}
	virtio_cwrite(vgdev->vdev, struct virtio_gpu_config,
		      events_clear, &events_clear);
}

static void virtio_gpu_init_vq(struct virtio_gpu_queue *vgvq,
			       void (*work_func)(struct work_struct *work))
{
	spin_lock_init(&vgvq->qlock);
	init_waitqueue_head(&vgvq->ack_queue);
	INIT_WORK(&vgvq->dequeue_work, work_func);
}

int virtio_gpu_driver_load(struct drm_device *dev, unsigned long flags)
{
	static vq_callback_t *callbacks[] = {
		virtio_gpu_ctrl_ack, virtio_gpu_cursor_ack
	};
	static const char *names[] = { "control", "cursor" };

	struct virtio_gpu_device *vgdev;
	/* this will expand later */
	struct virtqueue *vqs[2];
	u32 num_scanouts;
	int ret;

	if (!virtio_has_feature(dev->virtdev, VIRTIO_F_VERSION_1))
		return -ENODEV;

	vgdev = kzalloc(sizeof(struct virtio_gpu_device), GFP_KERNEL);
	if (!vgdev)
		return -ENOMEM;

	vgdev->ddev = dev;
	dev->dev_private = vgdev;
	vgdev->vdev = dev->virtdev;
	vgdev->dev = dev->dev;

	spin_lock_init(&vgdev->display_info_lock);
	spin_lock_init(&vgdev->ctx_id_idr_lock);
	idr_init(&vgdev->ctx_id_idr);
	spin_lock_init(&vgdev->resource_idr_lock);
	idr_init(&vgdev->resource_idr);
	init_waitqueue_head(&vgdev->resp_wq);
	virtio_gpu_init_vq(&vgdev->ctrlq, virtio_gpu_dequeue_ctrl_func);
	virtio_gpu_init_vq(&vgdev->cursorq, virtio_gpu_dequeue_cursor_func);

	spin_lock_init(&vgdev->fence_drv.lock);
	INIT_LIST_HEAD(&vgdev->fence_drv.fences);
	INIT_WORK(&vgdev->config_changed_work,
		  virtio_gpu_config_changed_work_func);

	ret = vgdev->vdev->config->find_vqs(vgdev->vdev, 2, vqs,
					    callbacks, names);
	if (ret) {
		DRM_ERROR("failed to find virt queues\n");
		goto err_vqs;
	}
	vgdev->ctrlq.vq = vqs[0];
	vgdev->cursorq.vq = vqs[1];
	ret = virtio_gpu_alloc_vbufs(vgdev);
	if (ret) {
		DRM_ERROR("failed to alloc vbufs\n");
		goto err_vbufs;
	}

	ret = virtio_gpu_ttm_init(vgdev);
	if (ret) {
		DRM_ERROR("failed to init ttm %d\n", ret);
		goto err_ttm;
	}

	/* get display info */
	virtio_cread(vgdev->vdev, struct virtio_gpu_config,
		     num_scanouts, &num_scanouts);
	vgdev->num_scanouts = min_t(uint32_t, num_scanouts,
				    VIRTIO_GPU_MAX_SCANOUTS);
	if (!vgdev->num_scanouts) {
		DRM_ERROR("num_scanouts is zero\n");
		ret = -EINVAL;
		goto err_scanouts;
	}

	ret = virtio_gpu_modeset_init(vgdev);
	if (ret)
		goto err_modeset;

	virtio_device_ready(vgdev->vdev);
	vgdev->vqs_ready = true;

	virtio_gpu_cmd_get_display_info(vgdev);
	wait_event_timeout(vgdev->resp_wq, !vgdev->display_info_pending,
			   5 * HZ);
	if (virtio_gpu_fbdev)
		virtio_gpu_fbdev_init(vgdev);

	return 0;

err_modeset:
err_scanouts:
	virtio_gpu_ttm_fini(vgdev);
err_ttm:
	virtio_gpu_free_vbufs(vgdev);
err_vbufs:
	vgdev->vdev->config->del_vqs(vgdev->vdev);
err_vqs:
	kfree(vgdev);
	return ret;
}

int virtio_gpu_driver_unload(struct drm_device *dev)
{
	struct virtio_gpu_device *vgdev = dev->dev_private;

	vgdev->vqs_ready = false;
	flush_work(&vgdev->ctrlq.dequeue_work);
	flush_work(&vgdev->cursorq.dequeue_work);
	flush_work(&vgdev->config_changed_work);
	vgdev->vdev->config->del_vqs(vgdev->vdev);

	virtio_gpu_modeset_fini(vgdev);
	virtio_gpu_ttm_fini(vgdev);
	virtio_gpu_free_vbufs(vgdev);
	kfree(vgdev);
	return 0;
}