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_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 */ 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 &args->offset); 120 else 121 return drm_gem_dumb_map_offset(file_priv, dev, args->handle, 122 &args->offset); 123 } 124 125 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 } 138 139