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_dumb_buffers.h> 29 #include <drm/drm_fourcc.h> 30 #include <drm/drm_gem.h> 31 #include <drm/drm_mode.h> 32 33 #include "drm_crtc_internal.h" 34 #include "drm_internal.h" 35 36 /** 37 * DOC: overview 38 * 39 * The KMS API doesn't standardize backing storage object creation and leaves it 40 * to driver-specific ioctls. Furthermore actually creating a buffer object even 41 * for GEM-based drivers is done through a driver-specific ioctl - GEM only has 42 * a common userspace interface for sharing and destroying objects. While not an 43 * issue for full-fledged graphics stacks that include device-specific userspace 44 * components (in libdrm for instance), this limit makes DRM-based early boot 45 * graphics unnecessarily complex. 46 * 47 * Dumb objects partly alleviate the problem by providing a standard API to 48 * create dumb buffers suitable for scanout, which can then be used to create 49 * KMS frame buffers. 50 * 51 * To support dumb objects drivers must implement the &drm_driver.dumb_create 52 * and &drm_driver.dumb_map_offset operations (the latter defaults to 53 * drm_gem_dumb_map_offset() if not set). Drivers that don't use GEM handles 54 * additionally need to implement the &drm_driver.dumb_destroy operation. See 55 * the callbacks for further details. 56 * 57 * Note that dumb objects may not be used for gpu acceleration, as has been 58 * attempted on some ARM embedded platforms. Such drivers really must have 59 * a hardware-specific ioctl to allocate suitable buffer objects. 60 */ 61 62 static int drm_mode_align_dumb(struct drm_mode_create_dumb *args, 63 unsigned long hw_pitch_align, 64 unsigned long hw_size_align) 65 { 66 u32 pitch = args->pitch; 67 u32 size; 68 69 if (!pitch) 70 return -EINVAL; 71 72 if (hw_pitch_align) 73 pitch = roundup(pitch, hw_pitch_align); 74 75 if (!hw_size_align) 76 hw_size_align = PAGE_SIZE; 77 else if (!IS_ALIGNED(hw_size_align, PAGE_SIZE)) 78 return -EINVAL; /* TODO: handle this if necessary */ 79 80 if (check_mul_overflow(args->height, pitch, &size)) 81 return -EINVAL; 82 size = ALIGN(size, hw_size_align); 83 if (!size) 84 return -EINVAL; 85 86 args->pitch = pitch; 87 args->size = size; 88 89 return 0; 90 } 91 92 /** 93 * drm_mode_size_dumb - Calculates the scanline and buffer sizes for dumb buffers 94 * @dev: DRM device 95 * @args: Parameters for the dumb buffer 96 * @hw_pitch_align: Hardware scanline alignment in bytes 97 * @hw_size_align: Hardware buffer-size alignment in bytes 98 * 99 * The helper drm_mode_size_dumb() calculates the size of the buffer 100 * allocation and the scanline size for a dumb buffer. Callers have to 101 * set the buffers width, height and color mode in the argument @arg. 102 * The helper validates the correctness of the input and tests for 103 * possible overflows. If successful, it returns the dumb buffer's 104 * required scanline pitch and size in &args. 105 * 106 * The parameter @hw_pitch_align allows the driver to specifies an 107 * alignment for the scanline pitch, if the hardware requires any. The 108 * calculated pitch will be a multiple of the alignment. The parameter 109 * @hw_size_align allows to specify an alignment for buffer sizes. The 110 * provided alignment should represent requirements of the graphics 111 * hardware. drm_mode_size_dumb() handles GEM-related constraints 112 * automatically across all drivers and hardware. For example, the 113 * returned buffer size is always a multiple of PAGE_SIZE, which is 114 * required by mmap(). 115 * 116 * Returns: 117 * Zero on success, or a negative error code otherwise. 118 */ 119 int drm_mode_size_dumb(struct drm_device *dev, 120 struct drm_mode_create_dumb *args, 121 unsigned long hw_pitch_align, 122 unsigned long hw_size_align) 123 { 124 u64 pitch = 0; 125 u32 fourcc; 126 127 /* 128 * The scanline pitch depends on the buffer width and the color 129 * format. The latter is specified as a color-mode constant for 130 * which we first have to find the corresponding color format. 131 * 132 * Different color formats can have the same color-mode constant. 133 * For example XRGB8888 and BGRX8888 both have a color mode of 32. 134 * It is possible to use different formats for dumb-buffer allocation 135 * and rendering as long as all involved formats share the same 136 * color-mode constant. 137 */ 138 fourcc = drm_driver_color_mode_format(dev, args->bpp); 139 if (fourcc != DRM_FORMAT_INVALID) { 140 const struct drm_format_info *info = drm_format_info(fourcc); 141 142 if (!info) 143 return -EINVAL; 144 pitch = drm_format_info_min_pitch(info, 0, args->width); 145 } else if (args->bpp) { 146 /* 147 * Some userspace throws in arbitrary values for bpp and 148 * relies on the kernel to figure it out. In this case we 149 * fall back to the old method of using bpp directly. The 150 * over-commitment of memory from the rounding is acceptable 151 * for compatibility with legacy userspace. We have a number 152 * of deprecated legacy values that are explicitly supported. 153 */ 154 switch (args->bpp) { 155 default: 156 drm_warn_once(dev, 157 "Unknown color mode %u; guessing buffer size.\n", 158 args->bpp); 159 fallthrough; 160 /* 161 * These constants represent various YUV formats supported by 162 * drm_gem_afbc_get_bpp(). 163 */ 164 case 12: // DRM_FORMAT_YUV420_8BIT 165 case 15: // DRM_FORMAT_YUV420_10BIT 166 case 30: // DRM_FORMAT_VUY101010 167 fallthrough; 168 /* 169 * Used by Mesa and Gstreamer to allocate NV formats and others 170 * as RGB buffers. Technically, XRGB16161616F formats are RGB, 171 * but the dumb buffers are not supposed to be used for anything 172 * beyond 32 bits per pixels. 173 */ 174 case 10: // DRM_FORMAT_NV{15,20,30}, DRM_FORMAT_P010 175 case 64: // DRM_FORMAT_{XRGB,XBGR,ARGB,ABGR}16161616F 176 pitch = args->width * DIV_ROUND_UP(args->bpp, SZ_8); 177 break; 178 } 179 } 180 181 if (!pitch || pitch > U32_MAX) 182 return -EINVAL; 183 184 args->pitch = pitch; 185 186 return drm_mode_align_dumb(args, hw_pitch_align, hw_size_align); 187 } 188 EXPORT_SYMBOL(drm_mode_size_dumb); 189 190 int drm_mode_create_dumb(struct drm_device *dev, 191 struct drm_mode_create_dumb *args, 192 struct drm_file *file_priv) 193 { 194 u32 cpp, stride, size; 195 196 if (!dev->driver->dumb_create) 197 return -ENOSYS; 198 if (!args->width || !args->height || !args->bpp) 199 return -EINVAL; 200 201 /* overflow checks for 32bit size calculations */ 202 if (args->bpp > U32_MAX - 8) 203 return -EINVAL; 204 cpp = DIV_ROUND_UP(args->bpp, 8); 205 if (cpp > U32_MAX / args->width) 206 return -EINVAL; 207 stride = cpp * args->width; 208 if (args->height > U32_MAX / stride) 209 return -EINVAL; 210 211 /* test for wrap-around */ 212 size = args->height * stride; 213 if (PAGE_ALIGN(size) == 0) 214 return -EINVAL; 215 216 /* 217 * handle, pitch and size are output parameters. Zero them out to 218 * prevent drivers from accidentally using uninitialized data. Since 219 * not all existing userspace is clearing these fields properly we 220 * cannot reject IOCTL with garbage in them. 221 */ 222 args->handle = 0; 223 args->pitch = 0; 224 args->size = 0; 225 226 return dev->driver->dumb_create(file_priv, dev, args); 227 } 228 229 int drm_mode_create_dumb_ioctl(struct drm_device *dev, 230 void *data, struct drm_file *file_priv) 231 { 232 struct drm_mode_create_dumb *args = data; 233 int err; 234 235 err = drm_mode_create_dumb(dev, args, file_priv); 236 if (err) { 237 args->handle = 0; 238 args->pitch = 0; 239 args->size = 0; 240 } 241 return err; 242 } 243 244 static int drm_mode_mmap_dumb(struct drm_device *dev, struct drm_mode_map_dumb *args, 245 struct drm_file *file_priv) 246 { 247 if (!dev->driver->dumb_create) 248 return -ENOSYS; 249 250 if (dev->driver->dumb_map_offset) 251 return dev->driver->dumb_map_offset(file_priv, dev, args->handle, 252 &args->offset); 253 else 254 return drm_gem_dumb_map_offset(file_priv, dev, args->handle, 255 &args->offset); 256 } 257 258 /** 259 * drm_mode_mmap_dumb_ioctl - create an mmap offset for a dumb backing storage buffer 260 * @dev: DRM device 261 * @data: ioctl data 262 * @file_priv: DRM file info 263 * 264 * Allocate an offset in the drm device node's address space to be able to 265 * memory map a dumb buffer. 266 * 267 * Called by the user via ioctl. 268 * 269 * Returns: 270 * Zero on success, negative errno on failure. 271 */ 272 int drm_mode_mmap_dumb_ioctl(struct drm_device *dev, 273 void *data, struct drm_file *file_priv) 274 { 275 struct drm_mode_map_dumb *args = data; 276 int err; 277 278 err = drm_mode_mmap_dumb(dev, args, file_priv); 279 if (err) 280 args->offset = 0; 281 return err; 282 } 283 284 int drm_mode_destroy_dumb(struct drm_device *dev, u32 handle, 285 struct drm_file *file_priv) 286 { 287 if (!dev->driver->dumb_create) 288 return -ENOSYS; 289 290 return drm_gem_handle_delete(file_priv, handle); 291 } 292 293 int drm_mode_destroy_dumb_ioctl(struct drm_device *dev, 294 void *data, struct drm_file *file_priv) 295 { 296 struct drm_mode_destroy_dumb *args = data; 297 298 return drm_mode_destroy_dumb(dev, args->handle, file_priv); 299 } 300