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