/*
 * 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 <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 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,
};
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");

DEFINE_DRM_GEM_FOPS(virtio_gpu_driver_fops);

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,
};