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 <linux/poll.h> 33 #include <linux/uaccess.h> 34 35 #include <drm/drm_crtc.h> 36 #include <drm/drm_debugfs_crc.h> 37 #include <drm/drm_drv.h> 38 #include <drm/drm_print.h> 39 40 #include "drm_internal.h" 41 42 /** 43 * DOC: CRC ABI 44 * 45 * DRM device drivers can provide to userspace CRC information of each frame as 46 * it reached a given hardware component (a CRC sampling "source"). 47 * 48 * Userspace can control generation of CRCs in a given CRTC by writing to the 49 * file dri/0/crtc-N/crc/control in debugfs, with N being the index of the CRTC. 50 * Accepted values are source names (which are driver-specific) and the "auto" 51 * keyword, which will let the driver select a default source of frame CRCs 52 * for this CRTC. 53 * 54 * Once frame CRC generation is enabled, userspace can capture them by reading 55 * the dri/0/crtc-N/crc/data file. Each line in that file contains the frame 56 * number in the first field and then a number of unsigned integer fields 57 * containing the CRC data. Fields are separated by a single space and the number 58 * of CRC fields is source-specific. 59 * 60 * Note that though in some cases the CRC is computed in a specified way and on 61 * the frame contents as supplied by userspace (eDP 1.3), in general the CRC 62 * computation is performed in an unspecified way and on frame contents that have 63 * been already processed in also an unspecified way and thus userspace cannot 64 * rely on being able to generate matching CRC values for the frame contents that 65 * it submits. In this general case, the maximum userspace can do is to compare 66 * the reported CRCs of frames that should have the same contents. 67 * 68 * On the driver side the implementation effort is minimal, drivers only need to 69 * implement &drm_crtc_funcs.set_crc_source and &drm_crtc_funcs.verify_crc_source. 70 * The debugfs files are automatically set up if those vfuncs are set. CRC samples 71 * need to be captured in the driver by calling drm_crtc_add_crc_entry(). 72 * Depending on the driver and HW requirements, &drm_crtc_funcs.set_crc_source 73 * may result in a commit (even a full modeset). 74 * 75 * CRC results must be reliable across non-full-modeset atomic commits, so if a 76 * commit via DRM_IOCTL_MODE_ATOMIC would disable or otherwise interfere with 77 * CRC generation, then the driver must mark that commit as a full modeset 78 * (drm_atomic_crtc_needs_modeset() should return true). As a result, to ensure 79 * consistent results, generic userspace must re-setup CRC generation after a 80 * legacy SETCRTC or an atomic commit with DRM_MODE_ATOMIC_ALLOW_MODESET. 81 */ 82 83 static int crc_control_show(struct seq_file *m, void *data) 84 { 85 struct drm_crtc *crtc = m->private; 86 87 if (crtc->funcs->get_crc_sources) { 88 size_t count; 89 const char *const *sources = crtc->funcs->get_crc_sources(crtc, 90 &count); 91 size_t values_cnt; 92 int i; 93 94 if (count == 0 || !sources) 95 goto out; 96 97 for (i = 0; i < count; i++) 98 if (!crtc->funcs->verify_crc_source(crtc, sources[i], 99 &values_cnt)) { 100 if (strcmp(sources[i], crtc->crc.source)) 101 seq_printf(m, "%s\n", sources[i]); 102 else 103 seq_printf(m, "%s*\n", sources[i]); 104 } 105 } 106 return 0; 107 108 out: 109 seq_printf(m, "%s*\n", crtc->crc.source); 110 return 0; 111 } 112 113 static int crc_control_open(struct inode *inode, struct file *file) 114 { 115 struct drm_crtc *crtc = inode->i_private; 116 117 return single_open(file, crc_control_show, crtc); 118 } 119 120 static ssize_t crc_control_write(struct file *file, const char __user *ubuf, 121 size_t len, loff_t *offp) 122 { 123 struct seq_file *m = file->private_data; 124 struct drm_crtc *crtc = m->private; 125 struct drm_crtc_crc *crc = &crtc->crc; 126 char *source; 127 size_t values_cnt; 128 int ret; 129 130 if (len == 0) 131 return 0; 132 133 if (len > PAGE_SIZE - 1) { 134 DRM_DEBUG_KMS("Expected < %lu bytes into crtc crc control\n", 135 PAGE_SIZE); 136 return -E2BIG; 137 } 138 139 source = memdup_user_nul(ubuf, len); 140 if (IS_ERR(source)) 141 return PTR_ERR(source); 142 143 if (source[len] == '\n') 144 source[len] = '\0'; 145 146 ret = crtc->funcs->verify_crc_source(crtc, source, &values_cnt); 147 if (ret) 148 return ret; 149 150 spin_lock_irq(&crc->lock); 151 152 if (crc->opened) { 153 spin_unlock_irq(&crc->lock); 154 kfree(source); 155 return -EBUSY; 156 } 157 158 kfree(crc->source); 159 crc->source = source; 160 161 spin_unlock_irq(&crc->lock); 162 163 *offp += len; 164 return len; 165 } 166 167 static const struct file_operations drm_crtc_crc_control_fops = { 168 .owner = THIS_MODULE, 169 .open = crc_control_open, 170 .read = seq_read, 171 .llseek = seq_lseek, 172 .release = single_release, 173 .write = crc_control_write 174 }; 175 176 static int crtc_crc_data_count(struct drm_crtc_crc *crc) 177 { 178 assert_spin_locked(&crc->lock); 179 return CIRC_CNT(crc->head, crc->tail, DRM_CRC_ENTRIES_NR); 180 } 181 182 static void crtc_crc_cleanup(struct drm_crtc_crc *crc) 183 { 184 kfree(crc->entries); 185 crc->overflow = false; 186 crc->entries = NULL; 187 crc->head = 0; 188 crc->tail = 0; 189 crc->values_cnt = 0; 190 crc->opened = false; 191 } 192 193 static int crtc_crc_open(struct inode *inode, struct file *filep) 194 { 195 struct drm_crtc *crtc = inode->i_private; 196 struct drm_crtc_crc *crc = &crtc->crc; 197 struct drm_crtc_crc_entry *entries = NULL; 198 size_t values_cnt; 199 int ret = 0; 200 201 if (drm_drv_uses_atomic_modeset(crtc->dev)) { 202 ret = drm_modeset_lock_single_interruptible(&crtc->mutex); 203 if (ret) 204 return ret; 205 206 if (!crtc->state->active) 207 ret = -EIO; 208 drm_modeset_unlock(&crtc->mutex); 209 210 if (ret) 211 return ret; 212 } 213 214 ret = crtc->funcs->verify_crc_source(crtc, crc->source, &values_cnt); 215 if (ret) 216 return ret; 217 218 if (WARN_ON(values_cnt > DRM_MAX_CRC_NR)) 219 return -EINVAL; 220 221 if (WARN_ON(values_cnt == 0)) 222 return -EINVAL; 223 224 entries = kcalloc(DRM_CRC_ENTRIES_NR, sizeof(*entries), GFP_KERNEL); 225 if (!entries) 226 return -ENOMEM; 227 228 spin_lock_irq(&crc->lock); 229 if (!crc->opened) { 230 crc->opened = true; 231 crc->entries = entries; 232 crc->values_cnt = values_cnt; 233 } else { 234 ret = -EBUSY; 235 } 236 spin_unlock_irq(&crc->lock); 237 238 if (ret) { 239 kfree(entries); 240 return ret; 241 } 242 243 ret = crtc->funcs->set_crc_source(crtc, crc->source); 244 if (ret) 245 goto err; 246 247 return 0; 248 249 err: 250 spin_lock_irq(&crc->lock); 251 crtc_crc_cleanup(crc); 252 spin_unlock_irq(&crc->lock); 253 return ret; 254 } 255 256 static int crtc_crc_release(struct inode *inode, struct file *filep) 257 { 258 struct drm_crtc *crtc = filep->f_inode->i_private; 259 struct drm_crtc_crc *crc = &crtc->crc; 260 261 crtc->funcs->set_crc_source(crtc, NULL); 262 263 spin_lock_irq(&crc->lock); 264 crtc_crc_cleanup(crc); 265 spin_unlock_irq(&crc->lock); 266 267 return 0; 268 } 269 270 /* 271 * 1 frame field of 10 chars plus a number of CRC fields of 10 chars each, space 272 * separated, with a newline at the end and null-terminated. 273 */ 274 #define LINE_LEN(values_cnt) (10 + 11 * values_cnt + 1 + 1) 275 #define MAX_LINE_LEN (LINE_LEN(DRM_MAX_CRC_NR)) 276 277 static ssize_t crtc_crc_read(struct file *filep, char __user *user_buf, 278 size_t count, loff_t *pos) 279 { 280 struct drm_crtc *crtc = filep->f_inode->i_private; 281 struct drm_crtc_crc *crc = &crtc->crc; 282 struct drm_crtc_crc_entry *entry; 283 char buf[MAX_LINE_LEN]; 284 int ret, i; 285 286 spin_lock_irq(&crc->lock); 287 288 if (!crc->source) { 289 spin_unlock_irq(&crc->lock); 290 return 0; 291 } 292 293 /* Nothing to read? */ 294 while (crtc_crc_data_count(crc) == 0) { 295 if (filep->f_flags & O_NONBLOCK) { 296 spin_unlock_irq(&crc->lock); 297 return -EAGAIN; 298 } 299 300 ret = wait_event_interruptible_lock_irq(crc->wq, 301 crtc_crc_data_count(crc), 302 crc->lock); 303 if (ret) { 304 spin_unlock_irq(&crc->lock); 305 return ret; 306 } 307 } 308 309 /* We know we have an entry to be read */ 310 entry = &crc->entries[crc->tail]; 311 312 if (count < LINE_LEN(crc->values_cnt)) { 313 spin_unlock_irq(&crc->lock); 314 return -EINVAL; 315 } 316 317 BUILD_BUG_ON_NOT_POWER_OF_2(DRM_CRC_ENTRIES_NR); 318 crc->tail = (crc->tail + 1) & (DRM_CRC_ENTRIES_NR - 1); 319 320 spin_unlock_irq(&crc->lock); 321 322 if (entry->has_frame_counter) 323 sprintf(buf, "0x%08x", entry->frame); 324 else 325 sprintf(buf, "XXXXXXXXXX"); 326 327 for (i = 0; i < crc->values_cnt; i++) 328 sprintf(buf + 10 + i * 11, " 0x%08x", entry->crcs[i]); 329 sprintf(buf + 10 + crc->values_cnt * 11, "\n"); 330 331 if (copy_to_user(user_buf, buf, LINE_LEN(crc->values_cnt))) 332 return -EFAULT; 333 334 return LINE_LEN(crc->values_cnt); 335 } 336 337 static unsigned int crtc_crc_poll(struct file *file, poll_table *wait) 338 { 339 struct drm_crtc *crtc = file->f_inode->i_private; 340 struct drm_crtc_crc *crc = &crtc->crc; 341 unsigned ret; 342 343 poll_wait(file, &crc->wq, wait); 344 345 spin_lock_irq(&crc->lock); 346 if (crc->source && crtc_crc_data_count(crc)) 347 ret = POLLIN | POLLRDNORM; 348 else 349 ret = 0; 350 spin_unlock_irq(&crc->lock); 351 352 return ret; 353 } 354 355 static const struct file_operations drm_crtc_crc_data_fops = { 356 .owner = THIS_MODULE, 357 .open = crtc_crc_open, 358 .read = crtc_crc_read, 359 .poll = crtc_crc_poll, 360 .release = crtc_crc_release, 361 }; 362 363 void drm_debugfs_crtc_crc_add(struct drm_crtc *crtc) 364 { 365 struct dentry *crc_ent; 366 367 if (!crtc->funcs->set_crc_source || !crtc->funcs->verify_crc_source) 368 return; 369 370 crc_ent = debugfs_create_dir("crc", crtc->debugfs_entry); 371 372 debugfs_create_file("control", S_IRUGO, crc_ent, crtc, 373 &drm_crtc_crc_control_fops); 374 debugfs_create_file("data", S_IRUGO, crc_ent, crtc, 375 &drm_crtc_crc_data_fops); 376 } 377 378 /** 379 * drm_crtc_add_crc_entry - Add entry with CRC information for a frame 380 * @crtc: CRTC to which the frame belongs 381 * @has_frame: whether this entry has a frame number to go with 382 * @frame: number of the frame these CRCs are about 383 * @crcs: array of CRC values, with length matching #drm_crtc_crc.values_cnt 384 * 385 * For each frame, the driver polls the source of CRCs for new data and calls 386 * this function to add them to the buffer from where userspace reads. 387 */ 388 int drm_crtc_add_crc_entry(struct drm_crtc *crtc, bool has_frame, 389 uint32_t frame, uint32_t *crcs) 390 { 391 struct drm_crtc_crc *crc = &crtc->crc; 392 struct drm_crtc_crc_entry *entry; 393 int head, tail; 394 unsigned long flags; 395 396 spin_lock_irqsave(&crc->lock, flags); 397 398 /* Caller may not have noticed yet that userspace has stopped reading */ 399 if (!crc->entries) { 400 spin_unlock_irqrestore(&crc->lock, flags); 401 return -EINVAL; 402 } 403 404 head = crc->head; 405 tail = crc->tail; 406 407 if (CIRC_SPACE(head, tail, DRM_CRC_ENTRIES_NR) < 1) { 408 bool was_overflow = crc->overflow; 409 410 crc->overflow = true; 411 spin_unlock_irqrestore(&crc->lock, flags); 412 413 if (!was_overflow) 414 DRM_ERROR("Overflow of CRC buffer, userspace reads too slow.\n"); 415 416 return -ENOBUFS; 417 } 418 419 entry = &crc->entries[head]; 420 entry->frame = frame; 421 entry->has_frame_counter = has_frame; 422 memcpy(&entry->crcs, crcs, sizeof(*crcs) * crc->values_cnt); 423 424 head = (head + 1) & (DRM_CRC_ENTRIES_NR - 1); 425 crc->head = head; 426 427 spin_unlock_irqrestore(&crc->lock, flags); 428 429 wake_up_interruptible(&crc->wq); 430 431 return 0; 432 } 433 EXPORT_SYMBOL_GPL(drm_crtc_add_crc_entry); 434