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/drmP.h>
27 #include <drm/drm_gem.h>
28
29 #include "drm_crtc_internal.h"
30
31 /**
32 * DOC: overview
33 *
34 * The KMS API doesn't standardize backing storage object creation and leaves it
35 * to driver-specific ioctls. Furthermore actually creating a buffer object even
36 * for GEM-based drivers is done through a driver-specific ioctl - GEM only has
37 * a common userspace interface for sharing and destroying objects. While not an
38 * issue for full-fledged graphics stacks that include device-specific userspace
39 * components (in libdrm for instance), this limit makes DRM-based early boot
40 * graphics unnecessarily complex.
41 *
42 * Dumb objects partly alleviate the problem by providing a standard API to
43 * create dumb buffers suitable for scanout, which can then be used to create
44 * KMS frame buffers.
45 *
46 * To support dumb objects drivers must implement the &drm_driver.dumb_create
47 * operation. &drm_driver.dumb_destroy defaults to drm_gem_dumb_destroy() if
48 * not set and &drm_driver.dumb_map_offset defaults to
49 * drm_gem_dumb_map_offset(). See the callbacks for further details.
50 *
51 * Note that dumb objects may not be used for gpu acceleration, as has been
52 * attempted on some ARM embedded platforms. Such drivers really must have
53 * a hardware-specific ioctl to allocate suitable buffer objects.
54 */
55
drm_mode_create_dumb_ioctl(struct drm_device * dev,void * data,struct drm_file * file_priv)56 int drm_mode_create_dumb_ioctl(struct drm_device *dev,
57 void *data, struct drm_file *file_priv)
58 {
59 struct drm_mode_create_dumb *args = data;
60 u32 cpp, stride, size;
61
62 if (!dev->driver->dumb_create)
63 return -ENOSYS;
64 if (!args->width || !args->height || !args->bpp)
65 return -EINVAL;
66
67 /* overflow checks for 32bit size calculations */
68 /* NOTE: DIV_ROUND_UP() can overflow */
69 cpp = DIV_ROUND_UP(args->bpp, 8);
70 if (!cpp || cpp > 0xffffffffU / args->width)
71 return -EINVAL;
72 stride = cpp * args->width;
73 if (args->height > 0xffffffffU / stride)
74 return -EINVAL;
75
76 /* test for wrap-around */
77 size = args->height * stride;
78 if (PAGE_ALIGN(size) == 0)
79 return -EINVAL;
80
81 /*
82 * handle, pitch and size are output parameters. Zero them out to
83 * prevent drivers from accidentally using uninitialized data. Since
84 * not all existing userspace is clearing these fields properly we
85 * cannot reject IOCTL with garbage in them.
86 */
87 args->handle = 0;
88 args->pitch = 0;
89 args->size = 0;
90
91 return dev->driver->dumb_create(file_priv, dev, args);
92 }
93
94 /**
95 * drm_mode_mmap_dumb_ioctl - create an mmap offset for a dumb backing storage buffer
96 * @dev: DRM device
97 * @data: ioctl data
98 * @file_priv: DRM file info
99 *
100 * Allocate an offset in the drm device node's address space to be able to
101 * memory map a dumb buffer.
102 *
103 * Called by the user via ioctl.
104 *
105 * Returns:
106 * Zero on success, negative errno on failure.
107 */
drm_mode_mmap_dumb_ioctl(struct drm_device * dev,void * data,struct drm_file * file_priv)108 int drm_mode_mmap_dumb_ioctl(struct drm_device *dev,
109 void *data, struct drm_file *file_priv)
110 {
111 struct drm_mode_map_dumb *args = data;
112
113 if (!dev->driver->dumb_create)
114 return -ENOSYS;
115
116 if (dev->driver->dumb_map_offset)
117 return dev->driver->dumb_map_offset(file_priv, dev,
118 args->handle,
119 (uint64_t *)&args->offset);
120 else
121 return drm_gem_dumb_map_offset(file_priv, dev, args->handle,
122 &args->offset);
123 }
124
drm_mode_destroy_dumb_ioctl(struct drm_device * dev,void * data,struct drm_file * file_priv)125 int drm_mode_destroy_dumb_ioctl(struct drm_device *dev,
126 void *data, struct drm_file *file_priv)
127 {
128 struct drm_mode_destroy_dumb *args = data;
129
130 if (!dev->driver->dumb_create)
131 return -ENOSYS;
132
133 if (dev->driver->dumb_destroy)
134 return dev->driver->dumb_destroy(file_priv, dev, args->handle);
135 else
136 return drm_gem_dumb_destroy(file_priv, dev, args->handle);
137 }
138