/*
 * Copyright (C) 2015 Red Hat, Inc.
 * All Rights Reserved.
 *
 * Authors:
 *    Dave Airlie <airlied@redhat.com>
 *    Gerd Hoffmann <kraxel@redhat.com>
 *
 * 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
 * VA LINUX SYSTEMS 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/module.h>
#include <linux/console.h>
#include <linux/pci.h>
#include <linux/poll.h>
#include <linux/wait.h>

#include <drm/drm.h>
#include <drm/drm_aperture.h>
#include <drm/drm_atomic_helper.h>
#include <drm/drm_drv.h>
#include <drm/drm_file.h>

#include "virtgpu_drv.h"

static const struct drm_driver driver;

static int virtio_gpu_modeset = -1;

MODULE_PARM_DESC(modeset, "Disable/Enable modesetting");
module_param_named(modeset, virtio_gpu_modeset, int, 0400);

static int virtio_gpu_pci_quirk(struct drm_device *dev, struct virtio_device *vdev)
{
	struct pci_dev *pdev = to_pci_dev(vdev->dev.parent);
	const char *pname = dev_name(&pdev->dev);
	bool vga = (pdev->class >> 8) == PCI_CLASS_DISPLAY_VGA;
	char unique[20];
	int ret;

	DRM_INFO("pci: %s detected at %s\n",
		 vga ? "virtio-vga" : "virtio-gpu-pci",
		 pname);
	if (vga) {
		ret = drm_aperture_remove_conflicting_pci_framebuffers(pdev, &driver);
		if (ret)
			return ret;
	}

	/*
	 * Normally the drm_dev_set_unique() call is done by core DRM.
	 * The following comment covers, why virtio cannot rely on it.
	 *
	 * Unlike the other virtual GPU drivers, virtio abstracts the
	 * underlying bus type by using struct virtio_device.
	 *
	 * Hence the dev_is_pci() check, used in core DRM, will fail
	 * and the unique returned will be the virtio_device "virtio0",
	 * while a "pci:..." one is required.
	 *
	 * A few other ideas were considered:
	 * - Extend the dev_is_pci() check [in drm_set_busid] to
	 *   consider virtio.
	 *   Seems like a bigger hack than what we have already.
	 *
	 * - Point drm_device::dev to the parent of the virtio_device
	 *   Semantic changes:
	 *   * Using the wrong device for i2c, framebuffer_alloc and
	 *     prime import.
	 *   Visual changes:
	 *   * Helpers such as DRM_DEV_ERROR, dev_info, drm_printer,
	 *     will print the wrong information.
	 *
	 * We could address the latter issues, by introducing
	 * drm_device::bus_dev, ... which would be used solely for this.
	 *
	 * So for the moment keep things as-is, with a bulky comment
	 * for the next person who feels like removing this
	 * drm_dev_set_unique() quirk.
	 */
	snprintf(unique, sizeof(unique), "pci:%s", pname);
	return drm_dev_set_unique(dev, unique);
}

static int virtio_gpu_probe(struct virtio_device *vdev)
{
	struct drm_device *dev;
	int ret;

	if (vgacon_text_force() && virtio_gpu_modeset == -1)
		return -EINVAL;

	if (virtio_gpu_modeset == 0)
		return -EINVAL;

	dev = drm_dev_alloc(&driver, &vdev->dev);
	if (IS_ERR(dev))
		return PTR_ERR(dev);
	vdev->priv = dev;

	if (!strcmp(vdev->dev.parent->bus->name, "pci")) {
		ret = virtio_gpu_pci_quirk(dev, vdev);
		if (ret)
			goto err_free;
	}

	ret = virtio_gpu_init(dev);
	if (ret)
		goto err_free;

	ret = drm_dev_register(dev, 0);
	if (ret)
		goto err_deinit;

	drm_fbdev_generic_setup(vdev->priv, 32);
	return 0;

err_deinit:
	virtio_gpu_deinit(dev);
err_free:
	drm_dev_put(dev);
	return ret;
}

static void virtio_gpu_remove(struct virtio_device *vdev)
{
	struct drm_device *dev = vdev->priv;

	drm_dev_unplug(dev);
	drm_atomic_helper_shutdown(dev);
	virtio_gpu_deinit(dev);
	drm_dev_put(dev);
}

static void virtio_gpu_config_changed(struct virtio_device *vdev)
{
	struct drm_device *dev = vdev->priv;
	struct virtio_gpu_device *vgdev = dev->dev_private;

	schedule_work(&vgdev->config_changed_work);
}

static __poll_t virtio_gpu_poll(struct file *filp,
				struct poll_table_struct *wait)
{
	struct drm_file *drm_file = filp->private_data;
	struct virtio_gpu_fpriv *vfpriv = drm_file->driver_priv;
	struct drm_device *dev = drm_file->minor->dev;
	struct drm_pending_event *e = NULL;
	__poll_t mask = 0;

	if (!vfpriv->ring_idx_mask)
		return drm_poll(filp, wait);

	poll_wait(filp, &drm_file->event_wait, wait);

	if (!list_empty(&drm_file->event_list)) {
		spin_lock_irq(&dev->event_lock);
		e = list_first_entry(&drm_file->event_list,
				     struct drm_pending_event, link);
		drm_file->event_space += e->event->length;
		list_del(&e->link);
		spin_unlock_irq(&dev->event_lock);

		kfree(e);
		mask |= EPOLLIN | EPOLLRDNORM;
	}

	return mask;
}

static struct virtio_device_id id_table[] = {
	{ VIRTIO_ID_GPU, VIRTIO_DEV_ANY_ID },
	{ 0 },
};

static unsigned int features[] = {
#ifdef __LITTLE_ENDIAN
	/*
	 * Gallium command stream send by virgl is native endian.
	 * Because of that we only support little endian guests on
	 * little endian hosts.
	 */
	VIRTIO_GPU_F_VIRGL,
#endif
	VIRTIO_GPU_F_EDID,
	VIRTIO_GPU_F_RESOURCE_UUID,
	VIRTIO_GPU_F_RESOURCE_BLOB,
	VIRTIO_GPU_F_CONTEXT_INIT,
};
static struct virtio_driver virtio_gpu_driver = {
	.feature_table = features,
	.feature_table_size = ARRAY_SIZE(features),
	.driver.name = KBUILD_MODNAME,
	.driver.owner = THIS_MODULE,
	.id_table = id_table,
	.probe = virtio_gpu_probe,
	.remove = virtio_gpu_remove,
	.config_changed = virtio_gpu_config_changed
};

module_virtio_driver(virtio_gpu_driver);

MODULE_DEVICE_TABLE(virtio, id_table);
MODULE_DESCRIPTION("Virtio GPU driver");
MODULE_LICENSE("GPL and additional rights");
MODULE_AUTHOR("Dave Airlie <airlied@redhat.com>");
MODULE_AUTHOR("Gerd Hoffmann <kraxel@redhat.com>");
MODULE_AUTHOR("Alon Levy");

static const struct file_operations virtio_gpu_driver_fops = {
	.owner          = THIS_MODULE,
	.open           = drm_open,
	.release        = drm_release,
	.unlocked_ioctl = drm_ioctl,
	.compat_ioctl   = drm_compat_ioctl,
	.poll           = virtio_gpu_poll,
	.read           = drm_read,
	.llseek         = noop_llseek,
	.mmap           = drm_gem_mmap
};

static const struct drm_driver driver = {
	.driver_features = DRIVER_MODESET | DRIVER_GEM | DRIVER_RENDER | DRIVER_ATOMIC,
	.open = virtio_gpu_driver_open,
	.postclose = virtio_gpu_driver_postclose,

	.dumb_create = virtio_gpu_mode_dumb_create,
	.dumb_map_offset = virtio_gpu_mode_dumb_mmap,

#if defined(CONFIG_DEBUG_FS)
	.debugfs_init = virtio_gpu_debugfs_init,
#endif
	.prime_handle_to_fd = drm_gem_prime_handle_to_fd,
	.prime_fd_to_handle = drm_gem_prime_fd_to_handle,
	.gem_prime_mmap = drm_gem_prime_mmap,
	.gem_prime_import = virtgpu_gem_prime_import,
	.gem_prime_import_sg_table = virtgpu_gem_prime_import_sg_table,

	.gem_create_object = virtio_gpu_create_object,
	.fops = &virtio_gpu_driver_fops,

	.ioctls = virtio_gpu_ioctls,
	.num_ioctls = DRM_VIRTIO_NUM_IOCTLS,

	.name = DRIVER_NAME,
	.desc = DRIVER_DESC,
	.date = DRIVER_DATE,
	.major = DRIVER_MAJOR,
	.minor = DRIVER_MINOR,
	.patchlevel = DRIVER_PATCHLEVEL,

	.release = virtio_gpu_release,
};