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. The debugfs files are automatically 70 * set up if that vfunc is set. CRC samples need to be captured in the driver by 71 * calling drm_crtc_add_crc_entry(). 72 */ 73 74 static int crc_control_show(struct seq_file *m, void *data) 75 { 76 struct drm_crtc *crtc = m->private; 77 78 if (crtc->funcs->get_crc_sources) { 79 size_t count; 80 const char *const *sources = crtc->funcs->get_crc_sources(crtc, 81 &count); 82 size_t values_cnt; 83 int i; 84 85 if (count == 0 || !sources) 86 goto out; 87 88 for (i = 0; i < count; i++) 89 if (!crtc->funcs->verify_crc_source(crtc, sources[i], 90 &values_cnt)) { 91 if (strcmp(sources[i], crtc->crc.source)) 92 seq_printf(m, "%s\n", sources[i]); 93 else 94 seq_printf(m, "%s*\n", sources[i]); 95 } 96 } 97 return 0; 98 99 out: 100 seq_printf(m, "%s*\n", crtc->crc.source); 101 return 0; 102 } 103 104 static int crc_control_open(struct inode *inode, struct file *file) 105 { 106 struct drm_crtc *crtc = inode->i_private; 107 108 return single_open(file, crc_control_show, crtc); 109 } 110 111 static ssize_t crc_control_write(struct file *file, const char __user *ubuf, 112 size_t len, loff_t *offp) 113 { 114 struct seq_file *m = file->private_data; 115 struct drm_crtc *crtc = m->private; 116 struct drm_crtc_crc *crc = &crtc->crc; 117 char *source; 118 size_t values_cnt; 119 int ret; 120 121 if (len == 0) 122 return 0; 123 124 if (len > PAGE_SIZE - 1) { 125 DRM_DEBUG_KMS("Expected < %lu bytes into crtc crc control\n", 126 PAGE_SIZE); 127 return -E2BIG; 128 } 129 130 source = memdup_user_nul(ubuf, len); 131 if (IS_ERR(source)) 132 return PTR_ERR(source); 133 134 if (source[len] == '\n') 135 source[len] = '\0'; 136 137 ret = crtc->funcs->verify_crc_source(crtc, source, &values_cnt); 138 if (ret) 139 return ret; 140 141 spin_lock_irq(&crc->lock); 142 143 if (crc->opened) { 144 spin_unlock_irq(&crc->lock); 145 kfree(source); 146 return -EBUSY; 147 } 148 149 kfree(crc->source); 150 crc->source = source; 151 152 spin_unlock_irq(&crc->lock); 153 154 *offp += len; 155 return len; 156 } 157 158 static const struct file_operations drm_crtc_crc_control_fops = { 159 .owner = THIS_MODULE, 160 .open = crc_control_open, 161 .read = seq_read, 162 .llseek = seq_lseek, 163 .release = single_release, 164 .write = crc_control_write 165 }; 166 167 static int crtc_crc_data_count(struct drm_crtc_crc *crc) 168 { 169 assert_spin_locked(&crc->lock); 170 return CIRC_CNT(crc->head, crc->tail, DRM_CRC_ENTRIES_NR); 171 } 172 173 static void crtc_crc_cleanup(struct drm_crtc_crc *crc) 174 { 175 kfree(crc->entries); 176 crc->overflow = false; 177 crc->entries = NULL; 178 crc->head = 0; 179 crc->tail = 0; 180 crc->values_cnt = 0; 181 crc->opened = false; 182 } 183 184 static int crtc_crc_open(struct inode *inode, struct file *filep) 185 { 186 struct drm_crtc *crtc = inode->i_private; 187 struct drm_crtc_crc *crc = &crtc->crc; 188 struct drm_crtc_crc_entry *entries = NULL; 189 size_t values_cnt; 190 int ret = 0; 191 192 if (drm_drv_uses_atomic_modeset(crtc->dev)) { 193 ret = drm_modeset_lock_single_interruptible(&crtc->mutex); 194 if (ret) 195 return ret; 196 197 if (!crtc->state->active) 198 ret = -EIO; 199 drm_modeset_unlock(&crtc->mutex); 200 201 if (ret) 202 return ret; 203 } 204 205 ret = crtc->funcs->verify_crc_source(crtc, crc->source, &values_cnt); 206 if (ret) 207 return ret; 208 209 if (WARN_ON(values_cnt > DRM_MAX_CRC_NR)) 210 return -EINVAL; 211 212 if (WARN_ON(values_cnt == 0)) 213 return -EINVAL; 214 215 entries = kcalloc(DRM_CRC_ENTRIES_NR, sizeof(*entries), GFP_KERNEL); 216 if (!entries) 217 return -ENOMEM; 218 219 spin_lock_irq(&crc->lock); 220 if (!crc->opened) { 221 crc->opened = true; 222 crc->entries = entries; 223 crc->values_cnt = values_cnt; 224 } else { 225 ret = -EBUSY; 226 } 227 spin_unlock_irq(&crc->lock); 228 229 if (ret) { 230 kfree(entries); 231 return ret; 232 } 233 234 ret = crtc->funcs->set_crc_source(crtc, crc->source); 235 if (ret) 236 goto err; 237 238 return 0; 239 240 err: 241 spin_lock_irq(&crc->lock); 242 crtc_crc_cleanup(crc); 243 spin_unlock_irq(&crc->lock); 244 return ret; 245 } 246 247 static int crtc_crc_release(struct inode *inode, struct file *filep) 248 { 249 struct drm_crtc *crtc = filep->f_inode->i_private; 250 struct drm_crtc_crc *crc = &crtc->crc; 251 252 crtc->funcs->set_crc_source(crtc, NULL); 253 254 spin_lock_irq(&crc->lock); 255 crtc_crc_cleanup(crc); 256 spin_unlock_irq(&crc->lock); 257 258 return 0; 259 } 260 261 /* 262 * 1 frame field of 10 chars plus a number of CRC fields of 10 chars each, space 263 * separated, with a newline at the end and null-terminated. 264 */ 265 #define LINE_LEN(values_cnt) (10 + 11 * values_cnt + 1 + 1) 266 #define MAX_LINE_LEN (LINE_LEN(DRM_MAX_CRC_NR)) 267 268 static ssize_t crtc_crc_read(struct file *filep, char __user *user_buf, 269 size_t count, loff_t *pos) 270 { 271 struct drm_crtc *crtc = filep->f_inode->i_private; 272 struct drm_crtc_crc *crc = &crtc->crc; 273 struct drm_crtc_crc_entry *entry; 274 char buf[MAX_LINE_LEN]; 275 int ret, i; 276 277 spin_lock_irq(&crc->lock); 278 279 if (!crc->source) { 280 spin_unlock_irq(&crc->lock); 281 return 0; 282 } 283 284 /* Nothing to read? */ 285 while (crtc_crc_data_count(crc) == 0) { 286 if (filep->f_flags & O_NONBLOCK) { 287 spin_unlock_irq(&crc->lock); 288 return -EAGAIN; 289 } 290 291 ret = wait_event_interruptible_lock_irq(crc->wq, 292 crtc_crc_data_count(crc), 293 crc->lock); 294 if (ret) { 295 spin_unlock_irq(&crc->lock); 296 return ret; 297 } 298 } 299 300 /* We know we have an entry to be read */ 301 entry = &crc->entries[crc->tail]; 302 303 if (count < LINE_LEN(crc->values_cnt)) { 304 spin_unlock_irq(&crc->lock); 305 return -EINVAL; 306 } 307 308 BUILD_BUG_ON_NOT_POWER_OF_2(DRM_CRC_ENTRIES_NR); 309 crc->tail = (crc->tail + 1) & (DRM_CRC_ENTRIES_NR - 1); 310 311 spin_unlock_irq(&crc->lock); 312 313 if (entry->has_frame_counter) 314 sprintf(buf, "0x%08x", entry->frame); 315 else 316 sprintf(buf, "XXXXXXXXXX"); 317 318 for (i = 0; i < crc->values_cnt; i++) 319 sprintf(buf + 10 + i * 11, " 0x%08x", entry->crcs[i]); 320 sprintf(buf + 10 + crc->values_cnt * 11, "\n"); 321 322 if (copy_to_user(user_buf, buf, LINE_LEN(crc->values_cnt))) 323 return -EFAULT; 324 325 return LINE_LEN(crc->values_cnt); 326 } 327 328 static unsigned int crtc_crc_poll(struct file *file, poll_table *wait) 329 { 330 struct drm_crtc *crtc = file->f_inode->i_private; 331 struct drm_crtc_crc *crc = &crtc->crc; 332 unsigned ret; 333 334 poll_wait(file, &crc->wq, wait); 335 336 spin_lock_irq(&crc->lock); 337 if (crc->source && crtc_crc_data_count(crc)) 338 ret = POLLIN | POLLRDNORM; 339 else 340 ret = 0; 341 spin_unlock_irq(&crc->lock); 342 343 return ret; 344 } 345 346 static const struct file_operations drm_crtc_crc_data_fops = { 347 .owner = THIS_MODULE, 348 .open = crtc_crc_open, 349 .read = crtc_crc_read, 350 .poll = crtc_crc_poll, 351 .release = crtc_crc_release, 352 }; 353 354 void drm_debugfs_crtc_crc_add(struct drm_crtc *crtc) 355 { 356 struct dentry *crc_ent; 357 358 if (!crtc->funcs->set_crc_source || !crtc->funcs->verify_crc_source) 359 return; 360 361 crc_ent = debugfs_create_dir("crc", crtc->debugfs_entry); 362 363 debugfs_create_file("control", S_IRUGO, crc_ent, crtc, 364 &drm_crtc_crc_control_fops); 365 debugfs_create_file("data", S_IRUGO, crc_ent, crtc, 366 &drm_crtc_crc_data_fops); 367 } 368 369 /** 370 * drm_crtc_add_crc_entry - Add entry with CRC information for a frame 371 * @crtc: CRTC to which the frame belongs 372 * @has_frame: whether this entry has a frame number to go with 373 * @frame: number of the frame these CRCs are about 374 * @crcs: array of CRC values, with length matching #drm_crtc_crc.values_cnt 375 * 376 * For each frame, the driver polls the source of CRCs for new data and calls 377 * this function to add them to the buffer from where userspace reads. 378 */ 379 int drm_crtc_add_crc_entry(struct drm_crtc *crtc, bool has_frame, 380 uint32_t frame, uint32_t *crcs) 381 { 382 struct drm_crtc_crc *crc = &crtc->crc; 383 struct drm_crtc_crc_entry *entry; 384 int head, tail; 385 unsigned long flags; 386 387 spin_lock_irqsave(&crc->lock, flags); 388 389 /* Caller may not have noticed yet that userspace has stopped reading */ 390 if (!crc->entries) { 391 spin_unlock_irqrestore(&crc->lock, flags); 392 return -EINVAL; 393 } 394 395 head = crc->head; 396 tail = crc->tail; 397 398 if (CIRC_SPACE(head, tail, DRM_CRC_ENTRIES_NR) < 1) { 399 bool was_overflow = crc->overflow; 400 401 crc->overflow = true; 402 spin_unlock_irqrestore(&crc->lock, flags); 403 404 if (!was_overflow) 405 DRM_ERROR("Overflow of CRC buffer, userspace reads too slow.\n"); 406 407 return -ENOBUFS; 408 } 409 410 entry = &crc->entries[head]; 411 entry->frame = frame; 412 entry->has_frame_counter = has_frame; 413 memcpy(&entry->crcs, crcs, sizeof(*crcs) * crc->values_cnt); 414 415 head = (head + 1) & (DRM_CRC_ENTRIES_NR - 1); 416 crc->head = head; 417 418 spin_unlock_irqrestore(&crc->lock, flags); 419 420 wake_up_interruptible(&crc->wq); 421 422 return 0; 423 } 424 EXPORT_SYMBOL_GPL(drm_crtc_add_crc_entry); 425