/*
 * Copyright 2011 Red Hat, Inc.
 * Copyright © 2014 The Chromium OS Authors
 *
 * 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
 * on the rights to use, copy, modify, merge, publish, distribute, sub
 * license, and/or sell copies of the Software, and to permit persons to whom
 * them 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 MERCHANTIBILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS 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.
 *
 * Authors:
 *      Adam Jackson <ajax@redhat.com>
 *      Ben Widawsky <ben@bwidawsk.net>
 */

/*
 * This is vgem, a (non-hardware-backed) GEM service.  This is used by Mesa's
 * software renderer and the X server for efficient buffer sharing.
 */

#include <linux/dma-buf.h>
#include <linux/module.h>
#include <linux/device/faux.h>
#include <linux/shmem_fs.h>
#include <linux/vmalloc.h>

#include <drm/drm_drv.h>
#include <drm/drm_file.h>
#include <drm/drm_gem_shmem_helper.h>
#include <drm/drm_ioctl.h>
#include <drm/drm_managed.h>
#include <drm/drm_prime.h>

#include "vgem_drv.h"

#define DRIVER_NAME     "vgem"
#define DRIVER_DESC     "Virtual GEM provider"
#define DRIVER_MAJOR    1
#define DRIVER_MINOR    0

static struct vgem_device {
        struct drm_device drm;
        struct faux_device *faux_dev;
} *vgem_device;

static int vgem_open(struct drm_device *dev, struct drm_file *file)
{
        struct vgem_file *vfile;
        int ret;

        vfile = kzalloc_obj(*vfile);
        if (!vfile)
                return -ENOMEM;

        file->driver_priv = vfile;

        ret = vgem_fence_open(vfile);
        if (ret) {
                kfree(vfile);
                return ret;
        }

        return 0;
}

static void vgem_postclose(struct drm_device *dev, struct drm_file *file)
{
        struct vgem_file *vfile = file->driver_priv;

        vgem_fence_close(vfile);
        kfree(vfile);
}

static struct drm_ioctl_desc vgem_ioctls[] = {
        DRM_IOCTL_DEF_DRV(VGEM_FENCE_ATTACH, vgem_fence_attach_ioctl, DRM_RENDER_ALLOW),
        DRM_IOCTL_DEF_DRV(VGEM_FENCE_SIGNAL, vgem_fence_signal_ioctl, DRM_RENDER_ALLOW),
};

DEFINE_DRM_GEM_FOPS(vgem_driver_fops);

static struct drm_gem_object *vgem_gem_create_object(struct drm_device *dev, size_t size)
{
        struct drm_gem_shmem_object *obj;

        obj = kzalloc_obj(*obj);
        if (!obj)
                return ERR_PTR(-ENOMEM);

        /*
         * vgem doesn't have any begin/end cpu access ioctls, therefore must use
         * coherent memory or dma-buf sharing just wont work.
         */
        obj->map_wc = true;

        return &obj->base;
}

static const struct drm_driver vgem_driver = {
        .driver_features                = DRIVER_GEM | DRIVER_RENDER,
        .open                           = vgem_open,
        .postclose                      = vgem_postclose,
        .ioctls                         = vgem_ioctls,
        .num_ioctls                     = ARRAY_SIZE(vgem_ioctls),
        .fops                           = &vgem_driver_fops,

        DRM_GEM_SHMEM_DRIVER_OPS,
        .gem_create_object              = vgem_gem_create_object,

        .name   = DRIVER_NAME,
        .desc   = DRIVER_DESC,
        .major  = DRIVER_MAJOR,
        .minor  = DRIVER_MINOR,
};

static int __init vgem_init(void)
{
        int ret;
        struct faux_device *fdev;

        fdev = faux_device_create("vgem", NULL, NULL);
        if (!fdev)
                return -ENODEV;

        if (!devres_open_group(&fdev->dev, NULL, GFP_KERNEL)) {
                ret = -ENOMEM;
                goto out_unregister;
        }

        dma_coerce_mask_and_coherent(&fdev->dev,
                                     DMA_BIT_MASK(64));

        vgem_device = devm_drm_dev_alloc(&fdev->dev, &vgem_driver,
                                         struct vgem_device, drm);
        if (IS_ERR(vgem_device)) {
                ret = PTR_ERR(vgem_device);
                goto out_devres;
        }
        vgem_device->faux_dev = fdev;

        /* Final step: expose the device/driver to userspace */
        ret = drm_dev_register(&vgem_device->drm, 0);
        if (ret)
                goto out_devres;

        return 0;

out_devres:
        devres_release_group(&fdev->dev, NULL);
out_unregister:
        faux_device_destroy(fdev);
        return ret;
}

static void __exit vgem_exit(void)
{
        struct faux_device *fdev = vgem_device->faux_dev;

        drm_dev_unregister(&vgem_device->drm);
        devres_release_group(&fdev->dev, NULL);
        faux_device_destroy(fdev);
}

module_init(vgem_init);
module_exit(vgem_exit);

MODULE_AUTHOR("Red Hat, Inc.");
MODULE_AUTHOR("Intel Corporation");
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL and additional rights");