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 :ref:`index of 50 * the CRTC<crtc_index>`. Accepted values are source names (which are 51 * driver-specific) and the "auto" keyword, which will let the driver select a 52 * default source of frame CRCs 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 crc_control_show(struct seq_file * m,void * data)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 crc_control_open(struct inode * inode,struct file * file)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 crc_control_write(struct file * file,const char __user * ubuf,size_t len,loff_t * offp)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 - 1] == '\n') 144 source[len - 1] = '\0'; 145 146 ret = crtc->funcs->verify_crc_source(crtc, source, &values_cnt); 147 if (ret) { 148 kfree(source); 149 return ret; 150 } 151 152 spin_lock_irq(&crc->lock); 153 154 if (crc->opened) { 155 spin_unlock_irq(&crc->lock); 156 kfree(source); 157 return -EBUSY; 158 } 159 160 kfree(crc->source); 161 crc->source = source; 162 163 spin_unlock_irq(&crc->lock); 164 165 *offp += len; 166 return len; 167 } 168 169 static const struct file_operations drm_crtc_crc_control_fops = { 170 .owner = THIS_MODULE, 171 .open = crc_control_open, 172 .read = seq_read, 173 .llseek = seq_lseek, 174 .release = single_release, 175 .write = crc_control_write 176 }; 177 crtc_crc_data_count(struct drm_crtc_crc * crc)178 static int crtc_crc_data_count(struct drm_crtc_crc *crc) 179 { 180 assert_spin_locked(&crc->lock); 181 return CIRC_CNT(crc->head, crc->tail, DRM_CRC_ENTRIES_NR); 182 } 183 crtc_crc_cleanup(struct drm_crtc_crc * crc)184 static void crtc_crc_cleanup(struct drm_crtc_crc *crc) 185 { 186 kfree(crc->entries); 187 crc->overflow = false; 188 crc->entries = NULL; 189 crc->head = 0; 190 crc->tail = 0; 191 crc->values_cnt = 0; 192 crc->opened = false; 193 } 194 crtc_crc_open(struct inode * inode,struct file * filep)195 static int crtc_crc_open(struct inode *inode, struct file *filep) 196 { 197 struct drm_crtc *crtc = inode->i_private; 198 struct drm_crtc_crc *crc = &crtc->crc; 199 struct drm_crtc_crc_entry *entries = NULL; 200 size_t values_cnt; 201 int ret = 0; 202 203 if (drm_drv_uses_atomic_modeset(crtc->dev)) { 204 ret = drm_modeset_lock_single_interruptible(&crtc->mutex); 205 if (ret) 206 return ret; 207 208 if (!crtc->state->active) 209 ret = -EIO; 210 drm_modeset_unlock(&crtc->mutex); 211 212 if (ret) 213 return ret; 214 } 215 216 ret = crtc->funcs->verify_crc_source(crtc, crc->source, &values_cnt); 217 if (ret) 218 return ret; 219 220 if (WARN_ON(values_cnt > DRM_MAX_CRC_NR)) 221 return -EINVAL; 222 223 if (WARN_ON(values_cnt == 0)) 224 return -EINVAL; 225 226 entries = kcalloc(DRM_CRC_ENTRIES_NR, sizeof(*entries), GFP_KERNEL); 227 if (!entries) 228 return -ENOMEM; 229 230 spin_lock_irq(&crc->lock); 231 if (!crc->opened) { 232 crc->opened = true; 233 crc->entries = entries; 234 crc->values_cnt = values_cnt; 235 } else { 236 ret = -EBUSY; 237 } 238 spin_unlock_irq(&crc->lock); 239 240 if (ret) { 241 kfree(entries); 242 return ret; 243 } 244 245 ret = crtc->funcs->set_crc_source(crtc, crc->source); 246 if (ret) 247 goto err; 248 249 return 0; 250 251 err: 252 spin_lock_irq(&crc->lock); 253 crtc_crc_cleanup(crc); 254 spin_unlock_irq(&crc->lock); 255 return ret; 256 } 257 crtc_crc_release(struct inode * inode,struct file * filep)258 static int crtc_crc_release(struct inode *inode, struct file *filep) 259 { 260 struct drm_crtc *crtc = filep->f_inode->i_private; 261 struct drm_crtc_crc *crc = &crtc->crc; 262 263 /* terminate the infinite while loop if 'drm_dp_aux_crc_work' running */ 264 spin_lock_irq(&crc->lock); 265 crc->opened = false; 266 spin_unlock_irq(&crc->lock); 267 268 crtc->funcs->set_crc_source(crtc, NULL); 269 270 spin_lock_irq(&crc->lock); 271 crtc_crc_cleanup(crc); 272 spin_unlock_irq(&crc->lock); 273 274 return 0; 275 } 276 277 /* 278 * 1 frame field of 10 chars plus a number of CRC fields of 10 chars each, space 279 * separated, with a newline at the end and null-terminated. 280 */ 281 #define LINE_LEN(values_cnt) (10 + 11 * values_cnt + 1 + 1) 282 #define MAX_LINE_LEN (LINE_LEN(DRM_MAX_CRC_NR)) 283 crtc_crc_read(struct file * filep,char __user * user_buf,size_t count,loff_t * pos)284 static ssize_t crtc_crc_read(struct file *filep, char __user *user_buf, 285 size_t count, loff_t *pos) 286 { 287 struct drm_crtc *crtc = filep->f_inode->i_private; 288 struct drm_crtc_crc *crc = &crtc->crc; 289 struct drm_crtc_crc_entry *entry; 290 char buf[MAX_LINE_LEN]; 291 int ret, i; 292 293 spin_lock_irq(&crc->lock); 294 295 if (!crc->source) { 296 spin_unlock_irq(&crc->lock); 297 return 0; 298 } 299 300 /* Nothing to read? */ 301 while (crtc_crc_data_count(crc) == 0) { 302 if (filep->f_flags & O_NONBLOCK) { 303 spin_unlock_irq(&crc->lock); 304 return -EAGAIN; 305 } 306 307 ret = wait_event_interruptible_lock_irq(crc->wq, 308 crtc_crc_data_count(crc), 309 crc->lock); 310 if (ret) { 311 spin_unlock_irq(&crc->lock); 312 return ret; 313 } 314 } 315 316 /* We know we have an entry to be read */ 317 entry = &crc->entries[crc->tail]; 318 319 if (count < LINE_LEN(crc->values_cnt)) { 320 spin_unlock_irq(&crc->lock); 321 return -EINVAL; 322 } 323 324 BUILD_BUG_ON_NOT_POWER_OF_2(DRM_CRC_ENTRIES_NR); 325 crc->tail = (crc->tail + 1) & (DRM_CRC_ENTRIES_NR - 1); 326 327 spin_unlock_irq(&crc->lock); 328 329 if (entry->has_frame_counter) 330 sprintf(buf, "0x%08x", entry->frame); 331 else 332 sprintf(buf, "XXXXXXXXXX"); 333 334 for (i = 0; i < crc->values_cnt; i++) 335 sprintf(buf + 10 + i * 11, " 0x%08x", entry->crcs[i]); 336 sprintf(buf + 10 + crc->values_cnt * 11, "\n"); 337 338 if (copy_to_user(user_buf, buf, LINE_LEN(crc->values_cnt))) 339 return -EFAULT; 340 341 return LINE_LEN(crc->values_cnt); 342 } 343 crtc_crc_poll(struct file * file,poll_table * wait)344 static __poll_t crtc_crc_poll(struct file *file, poll_table *wait) 345 { 346 struct drm_crtc *crtc = file->f_inode->i_private; 347 struct drm_crtc_crc *crc = &crtc->crc; 348 __poll_t ret = 0; 349 350 poll_wait(file, &crc->wq, wait); 351 352 spin_lock_irq(&crc->lock); 353 if (crc->source && crtc_crc_data_count(crc)) 354 ret |= EPOLLIN | EPOLLRDNORM; 355 spin_unlock_irq(&crc->lock); 356 357 return ret; 358 } 359 360 static const struct file_operations drm_crtc_crc_data_fops = { 361 .owner = THIS_MODULE, 362 .open = crtc_crc_open, 363 .read = crtc_crc_read, 364 .poll = crtc_crc_poll, 365 .release = crtc_crc_release, 366 }; 367 drm_debugfs_crtc_crc_add(struct drm_crtc * crtc)368 void drm_debugfs_crtc_crc_add(struct drm_crtc *crtc) 369 { 370 struct dentry *crc_ent; 371 372 if (!crtc->funcs->set_crc_source || !crtc->funcs->verify_crc_source) 373 return; 374 375 crc_ent = debugfs_create_dir("crc", crtc->debugfs_entry); 376 377 debugfs_create_file("control", S_IRUGO | S_IWUSR, crc_ent, crtc, 378 &drm_crtc_crc_control_fops); 379 debugfs_create_file("data", S_IRUGO, crc_ent, crtc, 380 &drm_crtc_crc_data_fops); 381 } 382 383 /** 384 * drm_crtc_add_crc_entry - Add entry with CRC information for a frame 385 * @crtc: CRTC to which the frame belongs 386 * @has_frame: whether this entry has a frame number to go with 387 * @frame: number of the frame these CRCs are about 388 * @crcs: array of CRC values, with length matching #drm_crtc_crc.values_cnt 389 * 390 * For each frame, the driver polls the source of CRCs for new data and calls 391 * this function to add them to the buffer from where userspace reads. 392 */ drm_crtc_add_crc_entry(struct drm_crtc * crtc,bool has_frame,uint32_t frame,uint32_t * crcs)393 int drm_crtc_add_crc_entry(struct drm_crtc *crtc, bool has_frame, 394 uint32_t frame, uint32_t *crcs) 395 { 396 struct drm_crtc_crc *crc = &crtc->crc; 397 struct drm_crtc_crc_entry *entry; 398 int head, tail; 399 unsigned long flags; 400 401 spin_lock_irqsave(&crc->lock, flags); 402 403 /* Caller may not have noticed yet that userspace has stopped reading */ 404 if (!crc->entries) { 405 spin_unlock_irqrestore(&crc->lock, flags); 406 return -EINVAL; 407 } 408 409 head = crc->head; 410 tail = crc->tail; 411 412 if (CIRC_SPACE(head, tail, DRM_CRC_ENTRIES_NR) < 1) { 413 bool was_overflow = crc->overflow; 414 415 crc->overflow = true; 416 spin_unlock_irqrestore(&crc->lock, flags); 417 418 if (!was_overflow) 419 DRM_ERROR("Overflow of CRC buffer, userspace reads too slow.\n"); 420 421 return -ENOBUFS; 422 } 423 424 entry = &crc->entries[head]; 425 entry->frame = frame; 426 entry->has_frame_counter = has_frame; 427 memcpy(&entry->crcs, crcs, sizeof(*crcs) * crc->values_cnt); 428 429 head = (head + 1) & (DRM_CRC_ENTRIES_NR - 1); 430 crc->head = head; 431 432 spin_unlock_irqrestore(&crc->lock, flags); 433 434 wake_up_interruptible(&crc->wq); 435 436 return 0; 437 } 438 EXPORT_SYMBOL_GPL(drm_crtc_add_crc_entry); 439