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 56 int drm_mode_create_dumb(struct drm_device *dev, 57 struct drm_mode_create_dumb *args, 58 struct drm_file *file_priv) 59 { 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 if (args->bpp > U32_MAX - 8) 69 return -EINVAL; 70 cpp = DIV_ROUND_UP(args->bpp, 8); 71 if (cpp > U32_MAX / args->width) 72 return -EINVAL; 73 stride = cpp * args->width; 74 if (args->height > U32_MAX / stride) 75 return -EINVAL; 76 77 /* test for wrap-around */ 78 size = args->height * stride; 79 if (PAGE_ALIGN(size) == 0) 80 return -EINVAL; 81 82 /* 83 * handle, pitch and size are output parameters. Zero them out to 84 * prevent drivers from accidentally using uninitialized data. Since 85 * not all existing userspace is clearing these fields properly we 86 * cannot reject IOCTL with garbage in them. 87 */ 88 args->handle = 0; 89 args->pitch = 0; 90 args->size = 0; 91 92 return dev->driver->dumb_create(file_priv, dev, args); 93 } 94 95 int drm_mode_create_dumb_ioctl(struct drm_device *dev, 96 void *data, struct drm_file *file_priv) 97 { 98 return drm_mode_create_dumb(dev, data, file_priv); 99 } 100 101 /** 102 * drm_mode_mmap_dumb_ioctl - create an mmap offset for a dumb backing storage buffer 103 * @dev: DRM device 104 * @data: ioctl data 105 * @file_priv: DRM file info 106 * 107 * Allocate an offset in the drm device node's address space to be able to 108 * memory map a dumb buffer. 109 * 110 * Called by the user via ioctl. 111 * 112 * Returns: 113 * Zero on success, negative errno on failure. 114 */ 115 int drm_mode_mmap_dumb_ioctl(struct drm_device *dev, 116 void *data, struct drm_file *file_priv) 117 { 118 struct drm_mode_map_dumb *args = data; 119 120 if (!dev->driver->dumb_create) 121 return -ENOSYS; 122 123 if (dev->driver->dumb_map_offset) 124 return dev->driver->dumb_map_offset(file_priv, dev, 125 args->handle, 126 &args->offset); 127 else 128 return drm_gem_dumb_map_offset(file_priv, dev, args->handle, 129 &args->offset); 130 } 131 132 int drm_mode_destroy_dumb(struct drm_device *dev, u32 handle, 133 struct drm_file *file_priv) 134 { 135 if (!dev->driver->dumb_create) 136 return -ENOSYS; 137 138 if (dev->driver->dumb_destroy) 139 return dev->driver->dumb_destroy(file_priv, dev, handle); 140 else 141 return drm_gem_dumb_destroy(file_priv, dev, handle); 142 } 143 144 int drm_mode_destroy_dumb_ioctl(struct drm_device *dev, 145 void *data, struct drm_file *file_priv) 146 { 147 struct drm_mode_destroy_dumb *args = data; 148 149 return drm_mode_destroy_dumb(dev, args->handle, file_priv); 150 } 151