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#include "drm_internal.h"
33
34/**
35 * DOC: overview
36 *
37 * The KMS API doesn't standardize backing storage object creation and leaves it
38 * to driver-specific ioctls. Furthermore actually creating a buffer object even
39 * for GEM-based drivers is done through a driver-specific ioctl - GEM only has
40 * a common userspace interface for sharing and destroying objects. While not an
41 * issue for full-fledged graphics stacks that include device-specific userspace
42 * components (in libdrm for instance), this limit makes DRM-based early boot
43 * graphics unnecessarily complex.
44 *
45 * Dumb objects partly alleviate the problem by providing a standard API to
46 * create dumb buffers suitable for scanout, which can then be used to create
47 * KMS frame buffers.
48 *
49 * To support dumb objects drivers must implement the &drm_driver.dumb_create
50 * and &drm_driver.dumb_map_offset operations (the latter defaults to
51 * drm_gem_dumb_map_offset() if not set). Drivers that don't use GEM handles
52 * additionally need to implement the &drm_driver.dumb_destroy operation. See
53 * the callbacks for further details.
54 *
55 * Note that dumb objects may not be used for gpu acceleration, as has been
56 * attempted on some ARM embedded platforms. Such drivers really must have
57 * a hardware-specific ioctl to allocate suitable buffer objects.
58 */
59
60int drm_mode_create_dumb(struct drm_device *dev,
61 struct drm_mode_create_dumb *args,
62 struct drm_file *file_priv)
63{
64 u32 cpp, stride, size;
65
66 if (!dev->driver->dumb_create)
67 return -ENOSYS;
68 if (!args->width || !args->height || !args->bpp)
69 return -EINVAL;
70
71 /* overflow checks for 32bit size calculations */
72 if (args->bpp > U32_MAX - 8)
73 return -EINVAL;
74 cpp = DIV_ROUND_UP(args->bpp, 8);
75 if (cpp > U32_MAX / args->width)
76 return -EINVAL;
77 stride = cpp * args->width;
78 if (args->height > U32_MAX / stride)
79 return -EINVAL;
80
81 /* test for wrap-around */
82 size = args->height * stride;
83 if (PAGE_ALIGN(size) == 0)
84 return -EINVAL;
85
86 /*
87 * handle, pitch and size are output parameters. Zero them out to
88 * prevent drivers from accidentally using uninitialized data. Since
89 * not all existing userspace is clearing these fields properly we
90 * cannot reject IOCTL with garbage in them.
91 */
92 args->handle = 0;
93 args->pitch = 0;
94 args->size = 0;
95
96 return dev->driver->dumb_create(file_priv, dev, args);
97}
98
99int drm_mode_create_dumb_ioctl(struct drm_device *dev,
100 void *data, struct drm_file *file_priv)
101{
102 return drm_mode_create_dumb(dev, args: data, file_priv);
103}
104
105/**
106 * drm_mode_mmap_dumb_ioctl - create an mmap offset for a dumb backing storage buffer
107 * @dev: DRM device
108 * @data: ioctl data
109 * @file_priv: DRM file info
110 *
111 * Allocate an offset in the drm device node's address space to be able to
112 * memory map a dumb buffer.
113 *
114 * Called by the user via ioctl.
115 *
116 * Returns:
117 * Zero on success, negative errno on failure.
118 */
119int drm_mode_mmap_dumb_ioctl(struct drm_device *dev,
120 void *data, struct drm_file *file_priv)
121{
122 struct drm_mode_map_dumb *args = data;
123
124 if (!dev->driver->dumb_create)
125 return -ENOSYS;
126
127 if (dev->driver->dumb_map_offset)
128 return dev->driver->dumb_map_offset(file_priv, dev,
129 args->handle,
130 &args->offset);
131 else
132 return drm_gem_dumb_map_offset(file: file_priv, dev, handle: args->handle,
133 offset: &args->offset);
134}
135
136int drm_mode_destroy_dumb(struct drm_device *dev, u32 handle,
137 struct drm_file *file_priv)
138{
139 if (!dev->driver->dumb_create)
140 return -ENOSYS;
141
142 return drm_gem_handle_delete(filp: file_priv, handle);
143}
144
145int drm_mode_destroy_dumb_ioctl(struct drm_device *dev,
146 void *data, struct drm_file *file_priv)
147{
148 struct drm_mode_destroy_dumb *args = data;
149
150 return drm_mode_destroy_dumb(dev, handle: args->handle, file_priv);
151}
152