1/*
2 * Copyright 2011 Red Hat, Inc.
3 * Copyright © 2014 The Chromium OS Authors
4 *
5 * Permission is hereby granted, free of charge, to any person obtaining a
6 * copy of this software and associated documentation files (the "Software")
7 * to deal in the software without restriction, including without limitation
8 * on the rights to use, copy, modify, merge, publish, distribute, sub
9 * license, and/or sell copies of the Software, and to permit persons to whom
10 * them Software is furnished to do so, subject to the following conditions:
11 *
12 * The above copyright notice and this permission notice (including the next
13 * paragraph) shall be included in all copies or substantial portions of the
14 * Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTIBILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES, OR OTHER LIABILITY, WHETHER
20 * IN AN ACTION OF CONTRACT, TORT, OR OTHERWISE, ARISING FROM, OUT OF OR IN
21 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
22 *
23 * Authors:
24 * Adam Jackson <ajax@redhat.com>
25 * Ben Widawsky <ben@bwidawsk.net>
26 */
27
28/*
29 * This is vgem, a (non-hardware-backed) GEM service. This is used by Mesa's
30 * software renderer and the X server for efficient buffer sharing.
31 */
32
33#include <linux/dma-buf.h>
34#include <linux/module.h>
35#include <linux/device/faux.h>
36#include <linux/shmem_fs.h>
37#include <linux/vmalloc.h>
38
39#include <drm/drm_drv.h>
40#include <drm/drm_file.h>
41#include <drm/drm_gem_shmem_helper.h>
42#include <drm/drm_ioctl.h>
43#include <drm/drm_managed.h>
44#include <drm/drm_prime.h>
45
46#include "vgem_drv.h"
47
48#define DRIVER_NAME "vgem"
49#define DRIVER_DESC "Virtual GEM provider"
50#define DRIVER_MAJOR 1
51#define DRIVER_MINOR 0
52
53static struct vgem_device {
54 struct drm_device drm;
55 struct faux_device *faux_dev;
56} *vgem_device;
57
58static int vgem_open(struct drm_device *dev, struct drm_file *file)
59{
60 struct vgem_file *vfile;
61 int ret;
62
63 vfile = kzalloc(sizeof(*vfile), GFP_KERNEL);
64 if (!vfile)
65 return -ENOMEM;
66
67 file->driver_priv = vfile;
68
69 ret = vgem_fence_open(file: vfile);
70 if (ret) {
71 kfree(objp: vfile);
72 return ret;
73 }
74
75 return 0;
76}
77
78static void vgem_postclose(struct drm_device *dev, struct drm_file *file)
79{
80 struct vgem_file *vfile = file->driver_priv;
81
82 vgem_fence_close(file: vfile);
83 kfree(objp: vfile);
84}
85
86static struct drm_ioctl_desc vgem_ioctls[] = {
87 DRM_IOCTL_DEF_DRV(VGEM_FENCE_ATTACH, vgem_fence_attach_ioctl, DRM_RENDER_ALLOW),
88 DRM_IOCTL_DEF_DRV(VGEM_FENCE_SIGNAL, vgem_fence_signal_ioctl, DRM_RENDER_ALLOW),
89};
90
91DEFINE_DRM_GEM_FOPS(vgem_driver_fops);
92
93static struct drm_gem_object *vgem_gem_create_object(struct drm_device *dev, size_t size)
94{
95 struct drm_gem_shmem_object *obj;
96
97 obj = kzalloc(sizeof(*obj), GFP_KERNEL);
98 if (!obj)
99 return ERR_PTR(error: -ENOMEM);
100
101 /*
102 * vgem doesn't have any begin/end cpu access ioctls, therefore must use
103 * coherent memory or dma-buf sharing just wont work.
104 */
105 obj->map_wc = true;
106
107 return &obj->base;
108}
109
110static const struct drm_driver vgem_driver = {
111 .driver_features = DRIVER_GEM | DRIVER_RENDER,
112 .open = vgem_open,
113 .postclose = vgem_postclose,
114 .ioctls = vgem_ioctls,
115 .num_ioctls = ARRAY_SIZE(vgem_ioctls),
116 .fops = &vgem_driver_fops,
117
118 DRM_GEM_SHMEM_DRIVER_OPS,
119 .gem_create_object = vgem_gem_create_object,
120
121 .name = DRIVER_NAME,
122 .desc = DRIVER_DESC,
123 .major = DRIVER_MAJOR,
124 .minor = DRIVER_MINOR,
125};
126
127static int __init vgem_init(void)
128{
129 int ret;
130 struct faux_device *fdev;
131
132 fdev = faux_device_create(name: "vgem", NULL, NULL);
133 if (!fdev)
134 return -ENODEV;
135
136 if (!devres_open_group(dev: &fdev->dev, NULL, GFP_KERNEL)) {
137 ret = -ENOMEM;
138 goto out_unregister;
139 }
140
141 dma_coerce_mask_and_coherent(dev: &fdev->dev,
142 DMA_BIT_MASK(64));
143
144 vgem_device = devm_drm_dev_alloc(&fdev->dev, &vgem_driver,
145 struct vgem_device, drm);
146 if (IS_ERR(ptr: vgem_device)) {
147 ret = PTR_ERR(ptr: vgem_device);
148 goto out_devres;
149 }
150 vgem_device->faux_dev = fdev;
151
152 /* Final step: expose the device/driver to userspace */
153 ret = drm_dev_register(dev: &vgem_device->drm, flags: 0);
154 if (ret)
155 goto out_devres;
156
157 return 0;
158
159out_devres:
160 devres_release_group(dev: &fdev->dev, NULL);
161out_unregister:
162 faux_device_destroy(faux_dev: fdev);
163 return ret;
164}
165
166static void __exit vgem_exit(void)
167{
168 struct faux_device *fdev = vgem_device->faux_dev;
169
170 drm_dev_unregister(dev: &vgem_device->drm);
171 devres_release_group(dev: &fdev->dev, NULL);
172 faux_device_destroy(faux_dev: fdev);
173}
174
175module_init(vgem_init);
176module_exit(vgem_exit);
177
178MODULE_AUTHOR("Red Hat, Inc.");
179MODULE_AUTHOR("Intel Corporation");
180MODULE_DESCRIPTION(DRIVER_DESC);
181MODULE_LICENSE("GPL and additional rights");
182

source code of linux/drivers/gpu/drm/vgem/vgem_drv.c