1 /*
2 * Copyright (c) 2006-2008 Intel Corporation
3 * Copyright (c) 2007 Dave Airlie <airlied@linux.ie>
4 * Copyright (c) 2008 Red Hat Inc.
5 * Copyright (c) 2016 Intel Corporation
6 *
7 * Permission to use, copy, modify, distribute, and sell this software and its
8 * documentation for any purpose is hereby granted without fee, provided that
9 * the above copyright notice appear in all copies and that both that copyright
10 * notice and this permission notice appear in supporting documentation, and
11 * that the name of the copyright holders not be used in advertising or
12 * publicity pertaining to distribution of the software without specific,
13 * written prior permission. The copyright holders make no representations
14 * about the suitability of this software for any purpose. It is provided "as
15 * is" without express or implied warranty.
16 *
17 * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
18 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
19 * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
20 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
21 * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
22 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
23 * OF THIS SOFTWARE.
24 */
25
26 #include <drm/drm_device.h>
27 #include <drm/drm_drv.h>
28 #include <drm/drm_gem.h>
29 #include <drm/drm_mode.h>
30
31 #include "drm_crtc_internal.h"
32
33 /**
34 * DOC: overview
35 *
36 * The KMS API doesn't standardize backing storage object creation and leaves it
37 * to driver-specific ioctls. Furthermore actually creating a buffer object even
38 * for GEM-based drivers is done through a driver-specific ioctl - GEM only has
39 * a common userspace interface for sharing and destroying objects. While not an
40 * issue for full-fledged graphics stacks that include device-specific userspace
41 * components (in libdrm for instance), this limit makes DRM-based early boot
42 * graphics unnecessarily complex.
43 *
44 * Dumb objects partly alleviate the problem by providing a standard API to
45 * create dumb buffers suitable for scanout, which can then be used to create
46 * KMS frame buffers.
47 *
48 * To support dumb objects drivers must implement the &drm_driver.dumb_create
49 * operation. &drm_driver.dumb_destroy defaults to drm_gem_dumb_destroy() if
50 * not set and &drm_driver.dumb_map_offset defaults to
51 * drm_gem_dumb_map_offset(). See the callbacks for further details.
52 *
53 * Note that dumb objects may not be used for gpu acceleration, as has been
54 * attempted on some ARM embedded platforms. Such drivers really must have
55 * a hardware-specific ioctl to allocate suitable buffer objects.
56 */
57
58 int drm_mode_create_dumb(struct drm_device *dev,
59 struct drm_mode_create_dumb *args,
60 struct drm_file *file_priv)
61 {
62 u32 cpp, stride, size;
63
64 if (!dev->driver->dumb_create)
65 return -ENOSYS;
66 if (!args->width || !args->height || !args->bpp)
67 return -EINVAL;
68
69 /* overflow checks for 32bit size calculations */
70 if (args->bpp > U32_MAX - 8)
71 return -EINVAL;
72 cpp = DIV_ROUND_UP(args->bpp, 8);
73 if (cpp > U32_MAX / args->width)
74 return -EINVAL;
75 stride = cpp * args->width;
76 if (args->height > U32_MAX / stride)
77 return -EINVAL;
78
79 /* test for wrap-around */
80 size = args->height * stride;
81 if (PAGE_ALIGN(size) == 0)
82 return -EINVAL;
83
84 /*
85 * handle, pitch and size are output parameters. Zero them out to
86 * prevent drivers from accidentally using uninitialized data. Since
87 * not all existing userspace is clearing these fields properly we
88 * cannot reject IOCTL with garbage in them.
89 */
90 args->handle = 0;
91 args->pitch = 0;
92 args->size = 0;
93
94 return dev->driver->dumb_create(file_priv, dev, args);
95 }
96
97 int drm_mode_create_dumb_ioctl(struct drm_device *dev,
98 void *data, struct drm_file *file_priv)
99 {
100 return drm_mode_create_dumb(dev, data, file_priv);
101 }
102
103 /**
104 * drm_mode_mmap_dumb_ioctl - create an mmap offset for a dumb backing storage buffer
105 * @dev: DRM device
106 * @data: ioctl data
107 * @file_priv: DRM file info
108 *
109 * Allocate an offset in the drm device node's address space to be able to
110 * memory map a dumb buffer.
111 *
112 * Called by the user via ioctl.
113 *
114 * Returns:
115 * Zero on success, negative errno on failure.
116 */
117 int drm_mode_mmap_dumb_ioctl(struct drm_device *dev,
118 void *data, struct drm_file *file_priv)
119 {
120 struct drm_mode_map_dumb *args = data;
121
122 if (!dev->driver->dumb_create)
123 return -ENOSYS;
124
125 if (dev->driver->dumb_map_offset)
126 return dev->driver->dumb_map_offset(file_priv, dev,
127 args->handle,
128 &args->offset);
129 else
130 return drm_gem_dumb_map_offset(file_priv, dev, args->handle,
131 &args->offset);
132 }
133
134 int drm_mode_destroy_dumb(struct drm_device *dev, u32 handle,
135 struct drm_file *file_priv)
136 {
137 if (!dev->driver->dumb_create)
138 return -ENOSYS;
139
140 if (dev->driver->dumb_destroy)
141 return dev->driver->dumb_destroy(file_priv, dev, handle);
142 else
143 return drm_gem_dumb_destroy(file_priv, dev, handle);
144 }
145
146 int drm_mode_destroy_dumb_ioctl(struct drm_device *dev,
147 void *data, struct drm_file *file_priv)
148 {
149 struct drm_mode_destroy_dumb *args = data;
150
151 return drm_mode_destroy_dumb(dev, args->handle, file_priv);
152 }