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 #include <drm/drm_print.h> 33 34 #include "drm_crtc_internal.h" 35 #include "drm_internal.h" 36 37 /** 38 * DOC: overview 39 * 40 * The KMS API doesn't standardize backing storage object creation and leaves it 41 * to driver-specific ioctls. Furthermore actually creating a buffer object even 42 * for GEM-based drivers is done through a driver-specific ioctl - GEM only has 43 * a common userspace interface for sharing and destroying objects. While not an 44 * issue for full-fledged graphics stacks that include device-specific userspace 45 * components (in libdrm for instance), this limit makes DRM-based early boot 46 * graphics unnecessarily complex. 47 * 48 * Dumb objects partly alleviate the problem by providing a standard API to 49 * create dumb buffers suitable for scanout, which can then be used to create 50 * KMS frame buffers. 51 * 52 * To support dumb objects drivers must implement the &drm_driver.dumb_create 53 * and &drm_driver.dumb_map_offset operations (the latter defaults to 54 * drm_gem_dumb_map_offset() if not set). Drivers that don't use GEM handles 55 * additionally need to implement the &drm_driver.dumb_destroy operation. See 56 * the callbacks for further details. 57 * 58 * Note that dumb objects may not be used for gpu acceleration, as has been 59 * attempted on some ARM embedded platforms. Such drivers really must have 60 * a hardware-specific ioctl to allocate suitable buffer objects. 61 */ 62 63 static int drm_mode_align_dumb(struct drm_mode_create_dumb *args, 64 unsigned long hw_pitch_align, 65 unsigned long hw_size_align) 66 { 67 u32 pitch = args->pitch; 68 u32 size; 69 70 if (!pitch) 71 return -EINVAL; 72 73 if (hw_pitch_align) { 74 pitch = roundup(pitch, hw_pitch_align); 75 if (pitch < hw_pitch_align) 76 return -EINVAL; 77 } 78 79 if (!hw_size_align) 80 hw_size_align = PAGE_SIZE; 81 else if (!IS_ALIGNED(hw_size_align, PAGE_SIZE)) 82 return -EINVAL; /* TODO: handle this if necessary */ 83 84 if (check_mul_overflow(args->height, pitch, &size)) 85 return -EINVAL; 86 size = roundup(size, hw_size_align); 87 if (!size) 88 return -EINVAL; 89 90 args->pitch = pitch; 91 args->size = size; 92 93 return 0; 94 } 95 96 /** 97 * drm_mode_size_dumb - Calculates the scanline and buffer sizes for dumb buffers 98 * @dev: DRM device 99 * @args: Parameters for the dumb buffer 100 * @hw_pitch_align: Hardware scanline alignment in bytes 101 * @hw_size_align: Hardware buffer-size alignment in bytes 102 * 103 * The helper drm_mode_size_dumb() calculates the size of the buffer 104 * allocation and the scanline size for a dumb buffer. Callers have to 105 * set the buffers width, height and color mode in the argument @arg. 106 * The helper validates the correctness of the input and tests for 107 * possible overflows. If successful, it returns the dumb buffer's 108 * required scanline pitch and size in &args. 109 * 110 * The parameter @hw_pitch_align allows the driver to specifies an 111 * alignment for the scanline pitch, if the hardware requires any. The 112 * calculated pitch will be a multiple of the alignment. The parameter 113 * @hw_size_align allows to specify an alignment for buffer sizes. The 114 * provided alignment should represent requirements of the graphics 115 * hardware. drm_mode_size_dumb() handles GEM-related constraints 116 * automatically across all drivers and hardware. For example, the 117 * returned buffer size is always a multiple of PAGE_SIZE, which is 118 * required by mmap(). 119 * 120 * Returns: 121 * Zero on success, or a negative error code otherwise. 122 */ 123 int drm_mode_size_dumb(struct drm_device *dev, 124 struct drm_mode_create_dumb *args, 125 unsigned long hw_pitch_align, 126 unsigned long hw_size_align) 127 { 128 u64 pitch = 0; 129 u32 fourcc; 130 131 /* 132 * The scanline pitch depends on the buffer width and the color 133 * format. The latter is specified as a color-mode constant for 134 * which we first have to find the corresponding color format. 135 * 136 * Different color formats can have the same color-mode constant. 137 * For example XRGB8888 and BGRX8888 both have a color mode of 32. 138 * It is possible to use different formats for dumb-buffer allocation 139 * and rendering as long as all involved formats share the same 140 * color-mode constant. 141 */ 142 fourcc = drm_driver_color_mode_format(dev, args->bpp); 143 if (fourcc != DRM_FORMAT_INVALID) { 144 const struct drm_format_info *info = drm_format_info(fourcc); 145 146 if (!info) 147 return -EINVAL; 148 pitch = drm_format_info_min_pitch(info, 0, args->width); 149 } else if (args->bpp) { 150 /* 151 * Some userspace throws in arbitrary values for bpp and 152 * relies on the kernel to figure it out. In this case we 153 * fall back to the old method of using bpp directly. The 154 * over-commitment of memory from the rounding is acceptable 155 * for compatibility with legacy userspace. We have a number 156 * of deprecated legacy values that are explicitly supported. 157 */ 158 switch (args->bpp) { 159 default: 160 drm_warn_once(dev, 161 "Unknown color mode %u; guessing buffer size.\n", 162 args->bpp); 163 fallthrough; 164 /* 165 * These constants represent various YUV formats supported by 166 * drm_gem_afbc_get_bpp(). 167 */ 168 case 12: // DRM_FORMAT_YUV420_8BIT 169 case 15: // DRM_FORMAT_YUV420_10BIT 170 case 30: // DRM_FORMAT_VUY101010 171 fallthrough; 172 /* 173 * Used by Mesa and Gstreamer to allocate NV formats and others 174 * as RGB buffers. Technically, XRGB16161616F formats are RGB, 175 * but the dumb buffers are not supposed to be used for anything 176 * beyond 32 bits per pixels. 177 */ 178 case 10: // DRM_FORMAT_NV{15,20,30}, DRM_FORMAT_P010 179 case 64: // DRM_FORMAT_{XRGB,XBGR,ARGB,ABGR}16161616F 180 pitch = args->width * DIV_ROUND_UP(args->bpp, SZ_8); 181 break; 182 } 183 } 184 185 if (!pitch || pitch > U32_MAX) 186 return -EINVAL; 187 188 args->pitch = pitch; 189 190 return drm_mode_align_dumb(args, hw_pitch_align, hw_size_align); 191 } 192 EXPORT_SYMBOL(drm_mode_size_dumb); 193 194 int drm_mode_create_dumb(struct drm_device *dev, 195 struct drm_mode_create_dumb *args, 196 struct drm_file *file_priv) 197 { 198 u32 cpp, stride, size; 199 200 if (!dev->driver->dumb_create) 201 return -ENOSYS; 202 if (!args->width || !args->height || !args->bpp) 203 return -EINVAL; 204 205 /* Reject unreasonable inputs early. Dumb buffers are for software 206 * rendering; nothing legitimate needs more than 8192x8192 at 32bpp. 207 * This prevents overflows in downstream alignment helpers. 208 */ 209 if (args->width >= 8192 || args->height >= 8192 || args->bpp > 32) 210 return -EINVAL; 211 212 /* overflow checks for 32bit size calculations */ 213 if (args->bpp > U32_MAX - 8) 214 return -EINVAL; 215 cpp = DIV_ROUND_UP(args->bpp, 8); 216 if (cpp > U32_MAX / args->width) 217 return -EINVAL; 218 stride = cpp * args->width; 219 if (args->height > U32_MAX / stride) 220 return -EINVAL; 221 222 /* test for wrap-around */ 223 size = args->height * stride; 224 if (PAGE_ALIGN(size) == 0) 225 return -EINVAL; 226 227 /* 228 * handle, pitch and size are output parameters. Zero them out to 229 * prevent drivers from accidentally using uninitialized data. Since 230 * not all existing userspace is clearing these fields properly we 231 * cannot reject IOCTL with garbage in them. 232 */ 233 args->handle = 0; 234 args->pitch = 0; 235 args->size = 0; 236 237 return dev->driver->dumb_create(file_priv, dev, args); 238 } 239 240 int drm_mode_create_dumb_ioctl(struct drm_device *dev, 241 void *data, struct drm_file *file_priv) 242 { 243 struct drm_mode_create_dumb *args = data; 244 int err; 245 246 err = drm_mode_create_dumb(dev, args, file_priv); 247 if (err) { 248 args->handle = 0; 249 args->pitch = 0; 250 args->size = 0; 251 } 252 return err; 253 } 254 255 static int drm_mode_mmap_dumb(struct drm_device *dev, struct drm_mode_map_dumb *args, 256 struct drm_file *file_priv) 257 { 258 if (!dev->driver->dumb_create) 259 return -ENOSYS; 260 261 if (dev->driver->dumb_map_offset) 262 return dev->driver->dumb_map_offset(file_priv, dev, args->handle, 263 &args->offset); 264 else 265 return drm_gem_dumb_map_offset(file_priv, dev, args->handle, 266 &args->offset); 267 } 268 269 /** 270 * drm_mode_mmap_dumb_ioctl - create an mmap offset for a dumb backing storage buffer 271 * @dev: DRM device 272 * @data: ioctl data 273 * @file_priv: DRM file info 274 * 275 * Allocate an offset in the drm device node's address space to be able to 276 * memory map a dumb buffer. 277 * 278 * Called by the user via ioctl. 279 * 280 * Returns: 281 * Zero on success, negative errno on failure. 282 */ 283 int drm_mode_mmap_dumb_ioctl(struct drm_device *dev, 284 void *data, struct drm_file *file_priv) 285 { 286 struct drm_mode_map_dumb *args = data; 287 int err; 288 289 err = drm_mode_mmap_dumb(dev, args, file_priv); 290 if (err) 291 args->offset = 0; 292 return err; 293 } 294 295 int drm_mode_destroy_dumb(struct drm_device *dev, u32 handle, 296 struct drm_file *file_priv) 297 { 298 if (!dev->driver->dumb_create) 299 return -ENOSYS; 300 301 return drm_gem_handle_delete(file_priv, handle); 302 } 303 304 int drm_mode_destroy_dumb_ioctl(struct drm_device *dev, 305 void *data, struct drm_file *file_priv) 306 { 307 struct drm_mode_destroy_dumb *args = data; 308 309 return drm_mode_destroy_dumb(dev, args->handle, file_priv); 310 } 311