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 60 int 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 99 int 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, 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 */ 119 int 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_priv, dev, args->handle, 133 &args->offset); 134 } 135 136 int 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 if (dev->driver->dumb_destroy) 143 return dev->driver->dumb_destroy(file_priv, dev, handle); 144 else 145 return drm_gem_dumb_destroy(file_priv, dev, handle); 146 } 147 148 int drm_mode_destroy_dumb_ioctl(struct drm_device *dev, 149 void *data, struct drm_file *file_priv) 150 { 151 struct drm_mode_destroy_dumb *args = data; 152 153 return drm_mode_destroy_dumb(dev, args->handle, file_priv); 154 } 155