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 76 if (!hw_size_align) 77 hw_size_align = PAGE_SIZE; 78 else if (!IS_ALIGNED(hw_size_align, PAGE_SIZE)) 79 return -EINVAL; /* TODO: handle this if necessary */ 80 81 if (check_mul_overflow(args->height, pitch, &size)) 82 return -EINVAL; 83 size = ALIGN(size, hw_size_align); 84 if (!size) 85 return -EINVAL; 86 87 args->pitch = pitch; 88 args->size = size; 89 90 return 0; 91 } 92 93 /** 94 * drm_mode_size_dumb - Calculates the scanline and buffer sizes for dumb buffers 95 * @dev: DRM device 96 * @args: Parameters for the dumb buffer 97 * @hw_pitch_align: Hardware scanline alignment in bytes 98 * @hw_size_align: Hardware buffer-size alignment in bytes 99 * 100 * The helper drm_mode_size_dumb() calculates the size of the buffer 101 * allocation and the scanline size for a dumb buffer. Callers have to 102 * set the buffers width, height and color mode in the argument @arg. 103 * The helper validates the correctness of the input and tests for 104 * possible overflows. If successful, it returns the dumb buffer's 105 * required scanline pitch and size in &args. 106 * 107 * The parameter @hw_pitch_align allows the driver to specifies an 108 * alignment for the scanline pitch, if the hardware requires any. The 109 * calculated pitch will be a multiple of the alignment. The parameter 110 * @hw_size_align allows to specify an alignment for buffer sizes. The 111 * provided alignment should represent requirements of the graphics 112 * hardware. drm_mode_size_dumb() handles GEM-related constraints 113 * automatically across all drivers and hardware. For example, the 114 * returned buffer size is always a multiple of PAGE_SIZE, which is 115 * required by mmap(). 116 * 117 * Returns: 118 * Zero on success, or a negative error code otherwise. 119 */ 120 int drm_mode_size_dumb(struct drm_device *dev, 121 struct drm_mode_create_dumb *args, 122 unsigned long hw_pitch_align, 123 unsigned long hw_size_align) 124 { 125 u64 pitch = 0; 126 u32 fourcc; 127 128 /* 129 * The scanline pitch depends on the buffer width and the color 130 * format. The latter is specified as a color-mode constant for 131 * which we first have to find the corresponding color format. 132 * 133 * Different color formats can have the same color-mode constant. 134 * For example XRGB8888 and BGRX8888 both have a color mode of 32. 135 * It is possible to use different formats for dumb-buffer allocation 136 * and rendering as long as all involved formats share the same 137 * color-mode constant. 138 */ 139 fourcc = drm_driver_color_mode_format(dev, args->bpp); 140 if (fourcc != DRM_FORMAT_INVALID) { 141 const struct drm_format_info *info = drm_format_info(fourcc); 142 143 if (!info) 144 return -EINVAL; 145 pitch = drm_format_info_min_pitch(info, 0, args->width); 146 } else if (args->bpp) { 147 /* 148 * Some userspace throws in arbitrary values for bpp and 149 * relies on the kernel to figure it out. In this case we 150 * fall back to the old method of using bpp directly. The 151 * over-commitment of memory from the rounding is acceptable 152 * for compatibility with legacy userspace. We have a number 153 * of deprecated legacy values that are explicitly supported. 154 */ 155 switch (args->bpp) { 156 default: 157 drm_warn_once(dev, 158 "Unknown color mode %u; guessing buffer size.\n", 159 args->bpp); 160 fallthrough; 161 /* 162 * These constants represent various YUV formats supported by 163 * drm_gem_afbc_get_bpp(). 164 */ 165 case 12: // DRM_FORMAT_YUV420_8BIT 166 case 15: // DRM_FORMAT_YUV420_10BIT 167 case 30: // DRM_FORMAT_VUY101010 168 fallthrough; 169 /* 170 * Used by Mesa and Gstreamer to allocate NV formats and others 171 * as RGB buffers. Technically, XRGB16161616F formats are RGB, 172 * but the dumb buffers are not supposed to be used for anything 173 * beyond 32 bits per pixels. 174 */ 175 case 10: // DRM_FORMAT_NV{15,20,30}, DRM_FORMAT_P010 176 case 64: // DRM_FORMAT_{XRGB,XBGR,ARGB,ABGR}16161616F 177 pitch = args->width * DIV_ROUND_UP(args->bpp, SZ_8); 178 break; 179 } 180 } 181 182 if (!pitch || pitch > U32_MAX) 183 return -EINVAL; 184 185 args->pitch = pitch; 186 187 return drm_mode_align_dumb(args, hw_pitch_align, hw_size_align); 188 } 189 EXPORT_SYMBOL(drm_mode_size_dumb); 190 191 int drm_mode_create_dumb(struct drm_device *dev, 192 struct drm_mode_create_dumb *args, 193 struct drm_file *file_priv) 194 { 195 u32 cpp, stride, size; 196 197 if (!dev->driver->dumb_create) 198 return -ENOSYS; 199 if (!args->width || !args->height || !args->bpp) 200 return -EINVAL; 201 202 /* overflow checks for 32bit size calculations */ 203 if (args->bpp > U32_MAX - 8) 204 return -EINVAL; 205 cpp = DIV_ROUND_UP(args->bpp, 8); 206 if (cpp > U32_MAX / args->width) 207 return -EINVAL; 208 stride = cpp * args->width; 209 if (args->height > U32_MAX / stride) 210 return -EINVAL; 211 212 /* test for wrap-around */ 213 size = args->height * stride; 214 if (PAGE_ALIGN(size) == 0) 215 return -EINVAL; 216 217 /* 218 * handle, pitch and size are output parameters. Zero them out to 219 * prevent drivers from accidentally using uninitialized data. Since 220 * not all existing userspace is clearing these fields properly we 221 * cannot reject IOCTL with garbage in them. 222 */ 223 args->handle = 0; 224 args->pitch = 0; 225 args->size = 0; 226 227 return dev->driver->dumb_create(file_priv, dev, args); 228 } 229 230 int drm_mode_create_dumb_ioctl(struct drm_device *dev, 231 void *data, struct drm_file *file_priv) 232 { 233 struct drm_mode_create_dumb *args = data; 234 int err; 235 236 err = drm_mode_create_dumb(dev, args, file_priv); 237 if (err) { 238 args->handle = 0; 239 args->pitch = 0; 240 args->size = 0; 241 } 242 return err; 243 } 244 245 static int drm_mode_mmap_dumb(struct drm_device *dev, struct drm_mode_map_dumb *args, 246 struct drm_file *file_priv) 247 { 248 if (!dev->driver->dumb_create) 249 return -ENOSYS; 250 251 if (dev->driver->dumb_map_offset) 252 return dev->driver->dumb_map_offset(file_priv, dev, args->handle, 253 &args->offset); 254 else 255 return drm_gem_dumb_map_offset(file_priv, dev, args->handle, 256 &args->offset); 257 } 258 259 /** 260 * drm_mode_mmap_dumb_ioctl - create an mmap offset for a dumb backing storage buffer 261 * @dev: DRM device 262 * @data: ioctl data 263 * @file_priv: DRM file info 264 * 265 * Allocate an offset in the drm device node's address space to be able to 266 * memory map a dumb buffer. 267 * 268 * Called by the user via ioctl. 269 * 270 * Returns: 271 * Zero on success, negative errno on failure. 272 */ 273 int drm_mode_mmap_dumb_ioctl(struct drm_device *dev, 274 void *data, struct drm_file *file_priv) 275 { 276 struct drm_mode_map_dumb *args = data; 277 int err; 278 279 err = drm_mode_mmap_dumb(dev, args, file_priv); 280 if (err) 281 args->offset = 0; 282 return err; 283 } 284 285 int drm_mode_destroy_dumb(struct drm_device *dev, u32 handle, 286 struct drm_file *file_priv) 287 { 288 if (!dev->driver->dumb_create) 289 return -ENOSYS; 290 291 return drm_gem_handle_delete(file_priv, handle); 292 } 293 294 int drm_mode_destroy_dumb_ioctl(struct drm_device *dev, 295 void *data, struct drm_file *file_priv) 296 { 297 struct drm_mode_destroy_dumb *args = data; 298 299 return drm_mode_destroy_dumb(dev, args->handle, file_priv); 300 } 301