/*
 * 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/aperture.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/poll.h>
#include <linux/vgaarb.h>
#include <linux/wait.h>

#include <drm/clients/drm_client_setup.h>
#include <drm/drm.h>
#include <drm/drm_atomic_helper.h>
#include <drm/drm_drv.h>
#include <drm/drm_fbdev_shmem.h>
#include <drm/drm_file.h>
#include <drm/drm_print.h>

#include "virtgpu_drv.h"

#define PCI_DEVICE_ID_VIRTIO_GPU 0x1050

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 pci_dev *pdev = to_pci_dev(dev->dev);
        const char *pname = dev_name(&pdev->dev);
        bool vga = pci_is_vga(pdev);
        int ret;

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

        return 0;
}

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

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

        if (virtio_gpu_modeset == 0)
                return -EINVAL;

        /*
         * The virtio-gpu device is a virtual device that doesn't have DMA
         * ops assigned to it, nor DMA mask set and etc. Its parent device
         * is actual GPU device we want to use it for the DRM's device in
         * order to benefit from using generic DRM APIs.
         */
        dev = drm_dev_alloc(&driver, vdev->dev.parent);
        if (IS_ERR(dev))
                return PTR_ERR(dev);
        vdev->priv = dev;

        if (dev_is_pci(vdev->dev.parent)) {
                ret = virtio_gpu_pci_quirk(dev);
                if (ret)
                        goto err_free;
        }

        dma_set_max_seg_size(dev->dev, dma_max_mapping_size(dev->dev) ?: UINT_MAX);
        ret = virtio_gpu_init(vdev, dev);
        if (ret)
                goto err_free;

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

        drm_client_setup(vdev->priv, NULL);

        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_shutdown(struct virtio_device *vdev)
{
        struct drm_device *dev = vdev->priv;

        /* stop talking to the device */
        drm_dev_unplug(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,
        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,
        .id_table = id_table,
        .probe = virtio_gpu_probe,
        .remove = virtio_gpu_remove,
        .shutdown = virtio_gpu_shutdown,
        .config_changed = virtio_gpu_config_changed
};

static int __init virtio_gpu_driver_init(void)
{
        struct pci_dev *pdev;
        int ret;

        pdev = pci_get_device(PCI_VENDOR_ID_REDHAT_QUMRANET,
                              PCI_DEVICE_ID_VIRTIO_GPU,
                              NULL);
        if (pdev && pci_is_vga(pdev)) {
                ret = vga_get_interruptible(pdev,
                        VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM);
                if (ret) {
                        pci_dev_put(pdev);
                        return ret;
                }
        }

        ret = register_virtio_driver(&virtio_gpu_driver);

        if (pdev) {
                if (pci_is_vga(pdev))
                        vga_put(pdev,
                                VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM);

                pci_dev_put(pdev);
        }

        return ret;
}

static void __exit virtio_gpu_driver_exit(void)
{
        unregister_virtio_driver(&virtio_gpu_driver);
}

module_init(virtio_gpu_driver_init);
module_exit(virtio_gpu_driver_exit);

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 = {
        /*
         * If KMS is disabled DRIVER_MODESET and DRIVER_ATOMIC are masked
         * out via drm_device::driver_features:
         */
        .driver_features = DRIVER_MODESET | DRIVER_GEM | DRIVER_RENDER | DRIVER_ATOMIC |
                           DRIVER_SYNCOBJ | DRIVER_SYNCOBJ_TIMELINE | DRIVER_CURSOR_HOTSPOT,
        .open = virtio_gpu_driver_open,
        .postclose = virtio_gpu_driver_postclose,

        .dumb_create = virtio_gpu_mode_dumb_create,

        DRM_FBDEV_SHMEM_DRIVER_OPS,

#if defined(CONFIG_DEBUG_FS)
        .debugfs_init = virtio_gpu_debugfs_init,
#endif
        .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,
        .major = DRIVER_MAJOR,
        .minor = DRIVER_MINOR,
        .patchlevel = DRIVER_PATCHLEVEL,

        .release = virtio_gpu_release,
};