1 /* 2 * Copyright © 2008 Intel Corporation 3 * Copyright © 2016 Collabora Ltd 4 * 5 * Permission is hereby granted, free of charge, to any person obtaining a 6 * copy of this software and associated documentation files (the "Software"), 7 * to deal in the Software without restriction, including without limitation 8 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 9 * and/or sell copies of the Software, and to permit persons to whom the 10 * Software is furnished to do so, subject to the following conditions: 11 * 12 * The above copyright notice and this permission notice (including the next 13 * paragraph) shall be included in all copies or substantial portions of the 14 * Software. 15 * 16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 21 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 22 * IN THE SOFTWARE. 23 * 24 * Based on code from the i915 driver. 25 * Original author: Damien Lespiau <damien.lespiau@intel.com> 26 * 27 */ 28 29 #include <linux/circ_buf.h> 30 #include <linux/ctype.h> 31 #include <linux/debugfs.h> 32 #include <drm/drmP.h> 33 #include "drm_internal.h" 34 35 /** 36 * DOC: CRC ABI 37 * 38 * DRM device drivers can provide to userspace CRC information of each frame as 39 * it reached a given hardware component (a CRC sampling "source"). 40 * 41 * Userspace can control generation of CRCs in a given CRTC by writing to the 42 * file dri/0/crtc-N/crc/control in debugfs, with N being the index of the CRTC. 43 * Accepted values are source names (which are driver-specific) and the "auto" 44 * keyword, which will let the driver select a default source of frame CRCs 45 * for this CRTC. 46 * 47 * Once frame CRC generation is enabled, userspace can capture them by reading 48 * the dri/0/crtc-N/crc/data file. Each line in that file contains the frame 49 * number in the first field and then a number of unsigned integer fields 50 * containing the CRC data. Fields are separated by a single space and the number 51 * of CRC fields is source-specific. 52 * 53 * Note that though in some cases the CRC is computed in a specified way and on 54 * the frame contents as supplied by userspace (eDP 1.3), in general the CRC 55 * computation is performed in an unspecified way and on frame contents that have 56 * been already processed in also an unspecified way and thus userspace cannot 57 * rely on being able to generate matching CRC values for the frame contents that 58 * it submits. In this general case, the maximum userspace can do is to compare 59 * the reported CRCs of frames that should have the same contents. 60 * 61 * On the driver side the implementation effort is minimal, drivers only need to 62 * implement &drm_crtc_funcs.set_crc_source. The debugfs files are automatically 63 * set up if that vfunc is set. CRC samples need to be captured in the driver by 64 * calling drm_crtc_add_crc_entry(). 65 */ 66 67 static int crc_control_show(struct seq_file *m, void *data) 68 { 69 struct drm_crtc *crtc = m->private; 70 71 seq_printf(m, "%s\n", crtc->crc.source); 72 73 return 0; 74 } 75 76 static int crc_control_open(struct inode *inode, struct file *file) 77 { 78 struct drm_crtc *crtc = inode->i_private; 79 80 return single_open(file, crc_control_show, crtc); 81 } 82 83 static ssize_t crc_control_write(struct file *file, const char __user *ubuf, 84 size_t len, loff_t *offp) 85 { 86 struct seq_file *m = file->private_data; 87 struct drm_crtc *crtc = m->private; 88 struct drm_crtc_crc *crc = &crtc->crc; 89 char *source; 90 91 if (len == 0) 92 return 0; 93 94 if (len > PAGE_SIZE - 1) { 95 DRM_DEBUG_KMS("Expected < %lu bytes into crtc crc control\n", 96 PAGE_SIZE); 97 return -E2BIG; 98 } 99 100 source = memdup_user_nul(ubuf, len); 101 if (IS_ERR(source)) 102 return PTR_ERR(source); 103 104 if (source[len] == '\n') 105 source[len] = '\0'; 106 107 spin_lock_irq(&crc->lock); 108 109 if (crc->opened) { 110 spin_unlock_irq(&crc->lock); 111 kfree(source); 112 return -EBUSY; 113 } 114 115 kfree(crc->source); 116 crc->source = source; 117 118 spin_unlock_irq(&crc->lock); 119 120 *offp += len; 121 return len; 122 } 123 124 static const struct file_operations drm_crtc_crc_control_fops = { 125 .owner = THIS_MODULE, 126 .open = crc_control_open, 127 .read = seq_read, 128 .llseek = seq_lseek, 129 .release = single_release, 130 .write = crc_control_write 131 }; 132 133 static int crtc_crc_data_count(struct drm_crtc_crc *crc) 134 { 135 assert_spin_locked(&crc->lock); 136 return CIRC_CNT(crc->head, crc->tail, DRM_CRC_ENTRIES_NR); 137 } 138 139 static void crtc_crc_cleanup(struct drm_crtc_crc *crc) 140 { 141 kfree(crc->entries); 142 crc->overflow = false; 143 crc->entries = NULL; 144 crc->head = 0; 145 crc->tail = 0; 146 crc->values_cnt = 0; 147 crc->opened = false; 148 } 149 150 static int crtc_crc_open(struct inode *inode, struct file *filep) 151 { 152 struct drm_crtc *crtc = inode->i_private; 153 struct drm_crtc_crc *crc = &crtc->crc; 154 struct drm_crtc_crc_entry *entries = NULL; 155 size_t values_cnt; 156 int ret = 0; 157 158 if (drm_drv_uses_atomic_modeset(crtc->dev)) { 159 ret = drm_modeset_lock_single_interruptible(&crtc->mutex); 160 if (ret) 161 return ret; 162 163 if (!crtc->state->active) 164 ret = -EIO; 165 drm_modeset_unlock(&crtc->mutex); 166 167 if (ret) 168 return ret; 169 } 170 171 spin_lock_irq(&crc->lock); 172 if (!crc->opened) 173 crc->opened = true; 174 else 175 ret = -EBUSY; 176 spin_unlock_irq(&crc->lock); 177 178 if (ret) 179 return ret; 180 181 ret = crtc->funcs->set_crc_source(crtc, crc->source, &values_cnt); 182 if (ret) 183 goto err; 184 185 if (WARN_ON(values_cnt > DRM_MAX_CRC_NR)) { 186 ret = -EINVAL; 187 goto err_disable; 188 } 189 190 if (WARN_ON(values_cnt == 0)) { 191 ret = -EINVAL; 192 goto err_disable; 193 } 194 195 entries = kcalloc(DRM_CRC_ENTRIES_NR, sizeof(*entries), GFP_KERNEL); 196 if (!entries) { 197 ret = -ENOMEM; 198 goto err_disable; 199 } 200 201 spin_lock_irq(&crc->lock); 202 crc->entries = entries; 203 crc->values_cnt = values_cnt; 204 205 /* 206 * Only return once we got a first frame, so userspace doesn't have to 207 * guess when this particular piece of HW will be ready to start 208 * generating CRCs. 209 */ 210 ret = wait_event_interruptible_lock_irq(crc->wq, 211 crtc_crc_data_count(crc), 212 crc->lock); 213 spin_unlock_irq(&crc->lock); 214 215 if (ret) 216 goto err_disable; 217 218 return 0; 219 220 err_disable: 221 crtc->funcs->set_crc_source(crtc, NULL, &values_cnt); 222 err: 223 spin_lock_irq(&crc->lock); 224 crtc_crc_cleanup(crc); 225 spin_unlock_irq(&crc->lock); 226 return ret; 227 } 228 229 static int crtc_crc_release(struct inode *inode, struct file *filep) 230 { 231 struct drm_crtc *crtc = filep->f_inode->i_private; 232 struct drm_crtc_crc *crc = &crtc->crc; 233 size_t values_cnt; 234 235 crtc->funcs->set_crc_source(crtc, NULL, &values_cnt); 236 237 spin_lock_irq(&crc->lock); 238 crtc_crc_cleanup(crc); 239 spin_unlock_irq(&crc->lock); 240 241 return 0; 242 } 243 244 /* 245 * 1 frame field of 10 chars plus a number of CRC fields of 10 chars each, space 246 * separated, with a newline at the end and null-terminated. 247 */ 248 #define LINE_LEN(values_cnt) (10 + 11 * values_cnt + 1 + 1) 249 #define MAX_LINE_LEN (LINE_LEN(DRM_MAX_CRC_NR)) 250 251 static ssize_t crtc_crc_read(struct file *filep, char __user *user_buf, 252 size_t count, loff_t *pos) 253 { 254 struct drm_crtc *crtc = filep->f_inode->i_private; 255 struct drm_crtc_crc *crc = &crtc->crc; 256 struct drm_crtc_crc_entry *entry; 257 char buf[MAX_LINE_LEN]; 258 int ret, i; 259 260 spin_lock_irq(&crc->lock); 261 262 if (!crc->source) { 263 spin_unlock_irq(&crc->lock); 264 return 0; 265 } 266 267 /* Nothing to read? */ 268 while (crtc_crc_data_count(crc) == 0) { 269 if (filep->f_flags & O_NONBLOCK) { 270 spin_unlock_irq(&crc->lock); 271 return -EAGAIN; 272 } 273 274 ret = wait_event_interruptible_lock_irq(crc->wq, 275 crtc_crc_data_count(crc), 276 crc->lock); 277 if (ret) { 278 spin_unlock_irq(&crc->lock); 279 return ret; 280 } 281 } 282 283 /* We know we have an entry to be read */ 284 entry = &crc->entries[crc->tail]; 285 286 if (count < LINE_LEN(crc->values_cnt)) { 287 spin_unlock_irq(&crc->lock); 288 return -EINVAL; 289 } 290 291 BUILD_BUG_ON_NOT_POWER_OF_2(DRM_CRC_ENTRIES_NR); 292 crc->tail = (crc->tail + 1) & (DRM_CRC_ENTRIES_NR - 1); 293 294 spin_unlock_irq(&crc->lock); 295 296 if (entry->has_frame_counter) 297 sprintf(buf, "0x%08x", entry->frame); 298 else 299 sprintf(buf, "XXXXXXXXXX"); 300 301 for (i = 0; i < crc->values_cnt; i++) 302 sprintf(buf + 10 + i * 11, " 0x%08x", entry->crcs[i]); 303 sprintf(buf + 10 + crc->values_cnt * 11, "\n"); 304 305 if (copy_to_user(user_buf, buf, LINE_LEN(crc->values_cnt))) 306 return -EFAULT; 307 308 return LINE_LEN(crc->values_cnt); 309 } 310 311 static unsigned int crtc_crc_poll(struct file *file, poll_table *wait) 312 { 313 struct drm_crtc *crtc = file->f_inode->i_private; 314 struct drm_crtc_crc *crc = &crtc->crc; 315 unsigned ret; 316 317 poll_wait(file, &crc->wq, wait); 318 319 spin_lock_irq(&crc->lock); 320 if (crc->source && crtc_crc_data_count(crc)) 321 ret = POLLIN | POLLRDNORM; 322 else 323 ret = 0; 324 spin_unlock_irq(&crc->lock); 325 326 return ret; 327 } 328 329 static const struct file_operations drm_crtc_crc_data_fops = { 330 .owner = THIS_MODULE, 331 .open = crtc_crc_open, 332 .read = crtc_crc_read, 333 .poll = crtc_crc_poll, 334 .release = crtc_crc_release, 335 }; 336 337 int drm_debugfs_crtc_crc_add(struct drm_crtc *crtc) 338 { 339 struct dentry *crc_ent, *ent; 340 341 if (!crtc->funcs->set_crc_source) 342 return 0; 343 344 crc_ent = debugfs_create_dir("crc", crtc->debugfs_entry); 345 if (!crc_ent) 346 return -ENOMEM; 347 348 ent = debugfs_create_file("control", S_IRUGO, crc_ent, crtc, 349 &drm_crtc_crc_control_fops); 350 if (!ent) 351 goto error; 352 353 ent = debugfs_create_file("data", S_IRUGO, crc_ent, crtc, 354 &drm_crtc_crc_data_fops); 355 if (!ent) 356 goto error; 357 358 return 0; 359 360 error: 361 debugfs_remove_recursive(crc_ent); 362 363 return -ENOMEM; 364 } 365 366 /** 367 * drm_crtc_add_crc_entry - Add entry with CRC information for a frame 368 * @crtc: CRTC to which the frame belongs 369 * @has_frame: whether this entry has a frame number to go with 370 * @frame: number of the frame these CRCs are about 371 * @crcs: array of CRC values, with length matching #drm_crtc_crc.values_cnt 372 * 373 * For each frame, the driver polls the source of CRCs for new data and calls 374 * this function to add them to the buffer from where userspace reads. 375 */ 376 int drm_crtc_add_crc_entry(struct drm_crtc *crtc, bool has_frame, 377 uint32_t frame, uint32_t *crcs) 378 { 379 struct drm_crtc_crc *crc = &crtc->crc; 380 struct drm_crtc_crc_entry *entry; 381 int head, tail; 382 383 spin_lock(&crc->lock); 384 385 /* Caller may not have noticed yet that userspace has stopped reading */ 386 if (!crc->entries) { 387 spin_unlock(&crc->lock); 388 return -EINVAL; 389 } 390 391 head = crc->head; 392 tail = crc->tail; 393 394 if (CIRC_SPACE(head, tail, DRM_CRC_ENTRIES_NR) < 1) { 395 bool was_overflow = crc->overflow; 396 397 crc->overflow = true; 398 spin_unlock(&crc->lock); 399 400 if (!was_overflow) 401 DRM_ERROR("Overflow of CRC buffer, userspace reads too slow.\n"); 402 403 return -ENOBUFS; 404 } 405 406 entry = &crc->entries[head]; 407 entry->frame = frame; 408 entry->has_frame_counter = has_frame; 409 memcpy(&entry->crcs, crcs, sizeof(*crcs) * crc->values_cnt); 410 411 head = (head + 1) & (DRM_CRC_ENTRIES_NR - 1); 412 crc->head = head; 413 414 spin_unlock(&crc->lock); 415 416 wake_up_interruptible(&crc->wq); 417 418 return 0; 419 } 420 EXPORT_SYMBOL_GPL(drm_crtc_add_crc_entry); 421