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 if (crtc->funcs->get_crc_sources) { 72 size_t count; 73 const char *const *sources = crtc->funcs->get_crc_sources(crtc, 74 &count); 75 size_t values_cnt; 76 int i; 77 78 if (count == 0 || !sources) 79 goto out; 80 81 for (i = 0; i < count; i++) 82 if (!crtc->funcs->verify_crc_source(crtc, sources[i], 83 &values_cnt)) { 84 if (strcmp(sources[i], crtc->crc.source)) 85 seq_printf(m, "%s\n", sources[i]); 86 else 87 seq_printf(m, "%s*\n", sources[i]); 88 } 89 } 90 return 0; 91 92 out: 93 seq_printf(m, "%s*\n", crtc->crc.source); 94 return 0; 95 } 96 97 static int crc_control_open(struct inode *inode, struct file *file) 98 { 99 struct drm_crtc *crtc = inode->i_private; 100 101 return single_open(file, crc_control_show, crtc); 102 } 103 104 static ssize_t crc_control_write(struct file *file, const char __user *ubuf, 105 size_t len, loff_t *offp) 106 { 107 struct seq_file *m = file->private_data; 108 struct drm_crtc *crtc = m->private; 109 struct drm_crtc_crc *crc = &crtc->crc; 110 char *source; 111 size_t values_cnt; 112 int ret; 113 114 if (len == 0) 115 return 0; 116 117 if (len > PAGE_SIZE - 1) { 118 DRM_DEBUG_KMS("Expected < %lu bytes into crtc crc control\n", 119 PAGE_SIZE); 120 return -E2BIG; 121 } 122 123 source = memdup_user_nul(ubuf, len); 124 if (IS_ERR(source)) 125 return PTR_ERR(source); 126 127 if (source[len] == '\n') 128 source[len] = '\0'; 129 130 ret = crtc->funcs->verify_crc_source(crtc, source, &values_cnt); 131 if (ret) 132 return ret; 133 134 spin_lock_irq(&crc->lock); 135 136 if (crc->opened) { 137 spin_unlock_irq(&crc->lock); 138 kfree(source); 139 return -EBUSY; 140 } 141 142 kfree(crc->source); 143 crc->source = source; 144 145 spin_unlock_irq(&crc->lock); 146 147 *offp += len; 148 return len; 149 } 150 151 static const struct file_operations drm_crtc_crc_control_fops = { 152 .owner = THIS_MODULE, 153 .open = crc_control_open, 154 .read = seq_read, 155 .llseek = seq_lseek, 156 .release = single_release, 157 .write = crc_control_write 158 }; 159 160 static int crtc_crc_data_count(struct drm_crtc_crc *crc) 161 { 162 assert_spin_locked(&crc->lock); 163 return CIRC_CNT(crc->head, crc->tail, DRM_CRC_ENTRIES_NR); 164 } 165 166 static void crtc_crc_cleanup(struct drm_crtc_crc *crc) 167 { 168 kfree(crc->entries); 169 crc->overflow = false; 170 crc->entries = NULL; 171 crc->head = 0; 172 crc->tail = 0; 173 crc->values_cnt = 0; 174 crc->opened = false; 175 } 176 177 static int crtc_crc_open(struct inode *inode, struct file *filep) 178 { 179 struct drm_crtc *crtc = inode->i_private; 180 struct drm_crtc_crc *crc = &crtc->crc; 181 struct drm_crtc_crc_entry *entries = NULL; 182 size_t values_cnt; 183 int ret = 0; 184 185 if (drm_drv_uses_atomic_modeset(crtc->dev)) { 186 ret = drm_modeset_lock_single_interruptible(&crtc->mutex); 187 if (ret) 188 return ret; 189 190 if (!crtc->state->active) 191 ret = -EIO; 192 drm_modeset_unlock(&crtc->mutex); 193 194 if (ret) 195 return ret; 196 } 197 198 ret = crtc->funcs->verify_crc_source(crtc, crc->source, &values_cnt); 199 if (ret) 200 return ret; 201 202 if (WARN_ON(values_cnt > DRM_MAX_CRC_NR)) 203 return -EINVAL; 204 205 if (WARN_ON(values_cnt == 0)) 206 return -EINVAL; 207 208 entries = kcalloc(DRM_CRC_ENTRIES_NR, sizeof(*entries), GFP_KERNEL); 209 if (!entries) 210 return -ENOMEM; 211 212 spin_lock_irq(&crc->lock); 213 if (!crc->opened) { 214 crc->opened = true; 215 crc->entries = entries; 216 crc->values_cnt = values_cnt; 217 } else { 218 ret = -EBUSY; 219 } 220 spin_unlock_irq(&crc->lock); 221 222 if (ret) { 223 kfree(entries); 224 return ret; 225 } 226 227 ret = crtc->funcs->set_crc_source(crtc, crc->source); 228 if (ret) 229 goto err; 230 231 return 0; 232 233 err: 234 spin_lock_irq(&crc->lock); 235 crtc_crc_cleanup(crc); 236 spin_unlock_irq(&crc->lock); 237 return ret; 238 } 239 240 static int crtc_crc_release(struct inode *inode, struct file *filep) 241 { 242 struct drm_crtc *crtc = filep->f_inode->i_private; 243 struct drm_crtc_crc *crc = &crtc->crc; 244 245 crtc->funcs->set_crc_source(crtc, NULL); 246 247 spin_lock_irq(&crc->lock); 248 crtc_crc_cleanup(crc); 249 spin_unlock_irq(&crc->lock); 250 251 return 0; 252 } 253 254 /* 255 * 1 frame field of 10 chars plus a number of CRC fields of 10 chars each, space 256 * separated, with a newline at the end and null-terminated. 257 */ 258 #define LINE_LEN(values_cnt) (10 + 11 * values_cnt + 1 + 1) 259 #define MAX_LINE_LEN (LINE_LEN(DRM_MAX_CRC_NR)) 260 261 static ssize_t crtc_crc_read(struct file *filep, char __user *user_buf, 262 size_t count, loff_t *pos) 263 { 264 struct drm_crtc *crtc = filep->f_inode->i_private; 265 struct drm_crtc_crc *crc = &crtc->crc; 266 struct drm_crtc_crc_entry *entry; 267 char buf[MAX_LINE_LEN]; 268 int ret, i; 269 270 spin_lock_irq(&crc->lock); 271 272 if (!crc->source) { 273 spin_unlock_irq(&crc->lock); 274 return 0; 275 } 276 277 /* Nothing to read? */ 278 while (crtc_crc_data_count(crc) == 0) { 279 if (filep->f_flags & O_NONBLOCK) { 280 spin_unlock_irq(&crc->lock); 281 return -EAGAIN; 282 } 283 284 ret = wait_event_interruptible_lock_irq(crc->wq, 285 crtc_crc_data_count(crc), 286 crc->lock); 287 if (ret) { 288 spin_unlock_irq(&crc->lock); 289 return ret; 290 } 291 } 292 293 /* We know we have an entry to be read */ 294 entry = &crc->entries[crc->tail]; 295 296 if (count < LINE_LEN(crc->values_cnt)) { 297 spin_unlock_irq(&crc->lock); 298 return -EINVAL; 299 } 300 301 BUILD_BUG_ON_NOT_POWER_OF_2(DRM_CRC_ENTRIES_NR); 302 crc->tail = (crc->tail + 1) & (DRM_CRC_ENTRIES_NR - 1); 303 304 spin_unlock_irq(&crc->lock); 305 306 if (entry->has_frame_counter) 307 sprintf(buf, "0x%08x", entry->frame); 308 else 309 sprintf(buf, "XXXXXXXXXX"); 310 311 for (i = 0; i < crc->values_cnt; i++) 312 sprintf(buf + 10 + i * 11, " 0x%08x", entry->crcs[i]); 313 sprintf(buf + 10 + crc->values_cnt * 11, "\n"); 314 315 if (copy_to_user(user_buf, buf, LINE_LEN(crc->values_cnt))) 316 return -EFAULT; 317 318 return LINE_LEN(crc->values_cnt); 319 } 320 321 static unsigned int crtc_crc_poll(struct file *file, poll_table *wait) 322 { 323 struct drm_crtc *crtc = file->f_inode->i_private; 324 struct drm_crtc_crc *crc = &crtc->crc; 325 unsigned ret; 326 327 poll_wait(file, &crc->wq, wait); 328 329 spin_lock_irq(&crc->lock); 330 if (crc->source && crtc_crc_data_count(crc)) 331 ret = POLLIN | POLLRDNORM; 332 else 333 ret = 0; 334 spin_unlock_irq(&crc->lock); 335 336 return ret; 337 } 338 339 static const struct file_operations drm_crtc_crc_data_fops = { 340 .owner = THIS_MODULE, 341 .open = crtc_crc_open, 342 .read = crtc_crc_read, 343 .poll = crtc_crc_poll, 344 .release = crtc_crc_release, 345 }; 346 347 int drm_debugfs_crtc_crc_add(struct drm_crtc *crtc) 348 { 349 struct dentry *crc_ent, *ent; 350 351 if (!crtc->funcs->set_crc_source || !crtc->funcs->verify_crc_source) 352 return 0; 353 354 crc_ent = debugfs_create_dir("crc", crtc->debugfs_entry); 355 if (!crc_ent) 356 return -ENOMEM; 357 358 ent = debugfs_create_file("control", S_IRUGO, crc_ent, crtc, 359 &drm_crtc_crc_control_fops); 360 if (!ent) 361 goto error; 362 363 ent = debugfs_create_file("data", S_IRUGO, crc_ent, crtc, 364 &drm_crtc_crc_data_fops); 365 if (!ent) 366 goto error; 367 368 return 0; 369 370 error: 371 debugfs_remove_recursive(crc_ent); 372 373 return -ENOMEM; 374 } 375 376 /** 377 * drm_crtc_add_crc_entry - Add entry with CRC information for a frame 378 * @crtc: CRTC to which the frame belongs 379 * @has_frame: whether this entry has a frame number to go with 380 * @frame: number of the frame these CRCs are about 381 * @crcs: array of CRC values, with length matching #drm_crtc_crc.values_cnt 382 * 383 * For each frame, the driver polls the source of CRCs for new data and calls 384 * this function to add them to the buffer from where userspace reads. 385 */ 386 int drm_crtc_add_crc_entry(struct drm_crtc *crtc, bool has_frame, 387 uint32_t frame, uint32_t *crcs) 388 { 389 struct drm_crtc_crc *crc = &crtc->crc; 390 struct drm_crtc_crc_entry *entry; 391 int head, tail; 392 393 spin_lock(&crc->lock); 394 395 /* Caller may not have noticed yet that userspace has stopped reading */ 396 if (!crc->entries) { 397 spin_unlock(&crc->lock); 398 return -EINVAL; 399 } 400 401 head = crc->head; 402 tail = crc->tail; 403 404 if (CIRC_SPACE(head, tail, DRM_CRC_ENTRIES_NR) < 1) { 405 bool was_overflow = crc->overflow; 406 407 crc->overflow = true; 408 spin_unlock(&crc->lock); 409 410 if (!was_overflow) 411 DRM_ERROR("Overflow of CRC buffer, userspace reads too slow.\n"); 412 413 return -ENOBUFS; 414 } 415 416 entry = &crc->entries[head]; 417 entry->frame = frame; 418 entry->has_frame_counter = has_frame; 419 memcpy(&entry->crcs, crcs, sizeof(*crcs) * crc->values_cnt); 420 421 head = (head + 1) & (DRM_CRC_ENTRIES_NR - 1); 422 crc->head = head; 423 424 spin_unlock(&crc->lock); 425 426 wake_up_interruptible(&crc->wq); 427 428 return 0; 429 } 430 EXPORT_SYMBOL_GPL(drm_crtc_add_crc_entry); 431