1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * PCI Express Precision Time Measurement 4 * Copyright (c) 2016, Intel Corporation. 5 */ 6 7 #include <linux/bitfield.h> 8 #include <linux/debugfs.h> 9 #include <linux/module.h> 10 #include <linux/init.h> 11 #include <linux/pci.h> 12 #include "../pci.h" 13 14 /* 15 * If the next upstream device supports PTM, return it; otherwise return 16 * NULL. PTM Messages are local, so both link partners must support it. 17 */ 18 static struct pci_dev *pci_upstream_ptm(struct pci_dev *dev) 19 { 20 struct pci_dev *ups = pci_upstream_bridge(dev); 21 22 /* 23 * Switch Downstream Ports are not permitted to have a PTM 24 * capability; their PTM behavior is controlled by the Upstream 25 * Port (PCIe r5.0, sec 7.9.16), so if the upstream bridge is a 26 * Switch Downstream Port, look up one more level. 27 */ 28 if (ups && pci_pcie_type(ups) == PCI_EXP_TYPE_DOWNSTREAM) 29 ups = pci_upstream_bridge(ups); 30 31 if (ups && ups->ptm_cap) 32 return ups; 33 34 return NULL; 35 } 36 37 /* 38 * Find the PTM Capability (if present) and extract the information we need 39 * to use it. 40 */ 41 void pci_ptm_init(struct pci_dev *dev) 42 { 43 u16 ptm; 44 u32 cap; 45 struct pci_dev *ups; 46 47 if (!pci_is_pcie(dev)) 48 return; 49 50 ptm = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_PTM); 51 if (!ptm) 52 return; 53 54 dev->ptm_cap = ptm; 55 pci_add_ext_cap_save_buffer(dev, PCI_EXT_CAP_ID_PTM, sizeof(u32)); 56 57 pci_read_config_dword(dev, ptm + PCI_PTM_CAP, &cap); 58 dev->ptm_granularity = FIELD_GET(PCI_PTM_GRANULARITY_MASK, cap); 59 60 /* 61 * Per the spec recommendation (PCIe r6.0, sec 7.9.15.3), select the 62 * furthest upstream Time Source as the PTM Root. For Endpoints, 63 * "the Effective Granularity is the maximum Local Clock Granularity 64 * reported by the PTM Root and all intervening PTM Time Sources." 65 */ 66 ups = pci_upstream_ptm(dev); 67 if (ups) { 68 if (ups->ptm_granularity == 0) 69 dev->ptm_granularity = 0; 70 else if (ups->ptm_granularity > dev->ptm_granularity) 71 dev->ptm_granularity = ups->ptm_granularity; 72 } else if (cap & PCI_PTM_CAP_ROOT) { 73 dev->ptm_root = 1; 74 } else if (pci_pcie_type(dev) == PCI_EXP_TYPE_RC_END) { 75 76 /* 77 * Per sec 7.9.15.3, this should be the Local Clock 78 * Granularity of the associated Time Source. But it 79 * doesn't say how to find that Time Source. 80 */ 81 dev->ptm_granularity = 0; 82 } 83 84 if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT || 85 pci_pcie_type(dev) == PCI_EXP_TYPE_UPSTREAM) 86 pci_enable_ptm(dev, NULL); 87 } 88 89 void pci_save_ptm_state(struct pci_dev *dev) 90 { 91 u16 ptm = dev->ptm_cap; 92 struct pci_cap_saved_state *save_state; 93 u32 *cap; 94 95 if (!ptm) 96 return; 97 98 save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_PTM); 99 if (!save_state) 100 return; 101 102 cap = (u32 *)&save_state->cap.data[0]; 103 pci_read_config_dword(dev, ptm + PCI_PTM_CTRL, cap); 104 } 105 106 void pci_restore_ptm_state(struct pci_dev *dev) 107 { 108 u16 ptm = dev->ptm_cap; 109 struct pci_cap_saved_state *save_state; 110 u32 *cap; 111 112 if (!ptm) 113 return; 114 115 save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_PTM); 116 if (!save_state) 117 return; 118 119 cap = (u32 *)&save_state->cap.data[0]; 120 pci_write_config_dword(dev, ptm + PCI_PTM_CTRL, *cap); 121 } 122 123 /* Enable PTM in the Control register if possible */ 124 static int __pci_enable_ptm(struct pci_dev *dev) 125 { 126 u16 ptm = dev->ptm_cap; 127 struct pci_dev *ups; 128 u32 ctrl; 129 130 if (!ptm) 131 return -EINVAL; 132 133 /* 134 * A device uses local PTM Messages to request time information 135 * from a PTM Root that's farther upstream. Every device along the 136 * path must support PTM and have it enabled so it can handle the 137 * messages. Therefore, if this device is not a PTM Root, the 138 * upstream link partner must have PTM enabled before we can enable 139 * PTM. 140 */ 141 if (!dev->ptm_root) { 142 ups = pci_upstream_ptm(dev); 143 if (!ups || !ups->ptm_enabled) 144 return -EINVAL; 145 } 146 147 pci_read_config_dword(dev, ptm + PCI_PTM_CTRL, &ctrl); 148 149 ctrl |= PCI_PTM_CTRL_ENABLE; 150 ctrl &= ~PCI_PTM_GRANULARITY_MASK; 151 ctrl |= FIELD_PREP(PCI_PTM_GRANULARITY_MASK, dev->ptm_granularity); 152 if (dev->ptm_root) 153 ctrl |= PCI_PTM_CTRL_ROOT; 154 155 pci_write_config_dword(dev, ptm + PCI_PTM_CTRL, ctrl); 156 return 0; 157 } 158 159 /** 160 * pci_enable_ptm() - Enable Precision Time Measurement 161 * @dev: PCI device 162 * @granularity: pointer to return granularity 163 * 164 * Enable Precision Time Measurement for @dev. If successful and 165 * @granularity is non-NULL, return the Effective Granularity. 166 * 167 * Return: zero if successful, or -EINVAL if @dev lacks a PTM Capability or 168 * is not a PTM Root and lacks an upstream path of PTM-enabled devices. 169 */ 170 int pci_enable_ptm(struct pci_dev *dev, u8 *granularity) 171 { 172 int rc; 173 char clock_desc[8]; 174 175 rc = __pci_enable_ptm(dev); 176 if (rc) 177 return rc; 178 179 dev->ptm_enabled = 1; 180 181 if (granularity) 182 *granularity = dev->ptm_granularity; 183 184 switch (dev->ptm_granularity) { 185 case 0: 186 snprintf(clock_desc, sizeof(clock_desc), "unknown"); 187 break; 188 case 255: 189 snprintf(clock_desc, sizeof(clock_desc), ">254ns"); 190 break; 191 default: 192 snprintf(clock_desc, sizeof(clock_desc), "%uns", 193 dev->ptm_granularity); 194 break; 195 } 196 pci_info(dev, "PTM enabled%s, %s granularity\n", 197 dev->ptm_root ? " (root)" : "", clock_desc); 198 199 return 0; 200 } 201 EXPORT_SYMBOL(pci_enable_ptm); 202 203 static void __pci_disable_ptm(struct pci_dev *dev) 204 { 205 u16 ptm = dev->ptm_cap; 206 u32 ctrl; 207 208 if (!ptm) 209 return; 210 211 pci_read_config_dword(dev, ptm + PCI_PTM_CTRL, &ctrl); 212 ctrl &= ~(PCI_PTM_CTRL_ENABLE | PCI_PTM_CTRL_ROOT); 213 pci_write_config_dword(dev, ptm + PCI_PTM_CTRL, ctrl); 214 } 215 216 /** 217 * pci_disable_ptm() - Disable Precision Time Measurement 218 * @dev: PCI device 219 * 220 * Disable Precision Time Measurement for @dev. 221 */ 222 void pci_disable_ptm(struct pci_dev *dev) 223 { 224 if (dev->ptm_enabled) { 225 __pci_disable_ptm(dev); 226 dev->ptm_enabled = 0; 227 } 228 } 229 EXPORT_SYMBOL(pci_disable_ptm); 230 231 /* 232 * Disable PTM, but preserve dev->ptm_enabled so we silently re-enable it on 233 * resume if necessary. 234 */ 235 void pci_suspend_ptm(struct pci_dev *dev) 236 { 237 if (dev->ptm_enabled) 238 __pci_disable_ptm(dev); 239 } 240 241 /* If PTM was enabled before suspend, re-enable it when resuming */ 242 void pci_resume_ptm(struct pci_dev *dev) 243 { 244 if (dev->ptm_enabled) 245 __pci_enable_ptm(dev); 246 } 247 248 bool pcie_ptm_enabled(struct pci_dev *dev) 249 { 250 if (!dev) 251 return false; 252 253 return dev->ptm_enabled; 254 } 255 EXPORT_SYMBOL(pcie_ptm_enabled); 256 257 static ssize_t context_update_write(struct file *file, const char __user *ubuf, 258 size_t count, loff_t *ppos) 259 { 260 struct pci_ptm_debugfs *ptm_debugfs = file->private_data; 261 char buf[7]; 262 int ret; 263 u8 mode; 264 265 if (!ptm_debugfs->ops->context_update_write) 266 return -EOPNOTSUPP; 267 268 if (count < 1 || count >= sizeof(buf)) 269 return -EINVAL; 270 271 ret = copy_from_user(buf, ubuf, count); 272 if (ret) 273 return -EFAULT; 274 275 buf[count] = '\0'; 276 277 if (sysfs_streq(buf, "auto")) 278 mode = PCIE_PTM_CONTEXT_UPDATE_AUTO; 279 else if (sysfs_streq(buf, "manual")) 280 mode = PCIE_PTM_CONTEXT_UPDATE_MANUAL; 281 else 282 return -EINVAL; 283 284 mutex_lock(&ptm_debugfs->lock); 285 ret = ptm_debugfs->ops->context_update_write(ptm_debugfs->pdata, mode); 286 mutex_unlock(&ptm_debugfs->lock); 287 if (ret) 288 return ret; 289 290 return count; 291 } 292 293 static ssize_t context_update_read(struct file *file, char __user *ubuf, 294 size_t count, loff_t *ppos) 295 { 296 struct pci_ptm_debugfs *ptm_debugfs = file->private_data; 297 char buf[8]; /* Extra space for NULL termination at the end */ 298 ssize_t pos; 299 u8 mode; 300 301 if (!ptm_debugfs->ops->context_update_read) 302 return -EOPNOTSUPP; 303 304 mutex_lock(&ptm_debugfs->lock); 305 ptm_debugfs->ops->context_update_read(ptm_debugfs->pdata, &mode); 306 mutex_unlock(&ptm_debugfs->lock); 307 308 if (mode == PCIE_PTM_CONTEXT_UPDATE_AUTO) 309 pos = scnprintf(buf, sizeof(buf), "auto\n"); 310 else 311 pos = scnprintf(buf, sizeof(buf), "manual\n"); 312 313 return simple_read_from_buffer(ubuf, count, ppos, buf, pos); 314 } 315 316 static const struct file_operations context_update_fops = { 317 .open = simple_open, 318 .read = context_update_read, 319 .write = context_update_write, 320 }; 321 322 static int context_valid_get(void *data, u64 *val) 323 { 324 struct pci_ptm_debugfs *ptm_debugfs = data; 325 bool valid; 326 int ret; 327 328 if (!ptm_debugfs->ops->context_valid_read) 329 return -EOPNOTSUPP; 330 331 mutex_lock(&ptm_debugfs->lock); 332 ret = ptm_debugfs->ops->context_valid_read(ptm_debugfs->pdata, &valid); 333 mutex_unlock(&ptm_debugfs->lock); 334 if (ret) 335 return ret; 336 337 *val = valid; 338 339 return 0; 340 } 341 342 static int context_valid_set(void *data, u64 val) 343 { 344 struct pci_ptm_debugfs *ptm_debugfs = data; 345 int ret; 346 347 if (!ptm_debugfs->ops->context_valid_write) 348 return -EOPNOTSUPP; 349 350 mutex_lock(&ptm_debugfs->lock); 351 ret = ptm_debugfs->ops->context_valid_write(ptm_debugfs->pdata, !!val); 352 mutex_unlock(&ptm_debugfs->lock); 353 354 return ret; 355 } 356 357 DEFINE_DEBUGFS_ATTRIBUTE(context_valid_fops, context_valid_get, 358 context_valid_set, "%llu\n"); 359 360 static int local_clock_get(void *data, u64 *val) 361 { 362 struct pci_ptm_debugfs *ptm_debugfs = data; 363 u64 clock; 364 int ret; 365 366 if (!ptm_debugfs->ops->local_clock_read) 367 return -EOPNOTSUPP; 368 369 ret = ptm_debugfs->ops->local_clock_read(ptm_debugfs->pdata, &clock); 370 if (ret) 371 return ret; 372 373 *val = clock; 374 375 return 0; 376 } 377 378 DEFINE_DEBUGFS_ATTRIBUTE(local_clock_fops, local_clock_get, NULL, "%llu\n"); 379 380 static int master_clock_get(void *data, u64 *val) 381 { 382 struct pci_ptm_debugfs *ptm_debugfs = data; 383 u64 clock; 384 int ret; 385 386 if (!ptm_debugfs->ops->master_clock_read) 387 return -EOPNOTSUPP; 388 389 ret = ptm_debugfs->ops->master_clock_read(ptm_debugfs->pdata, &clock); 390 if (ret) 391 return ret; 392 393 *val = clock; 394 395 return 0; 396 } 397 398 DEFINE_DEBUGFS_ATTRIBUTE(master_clock_fops, master_clock_get, NULL, "%llu\n"); 399 400 static int t1_get(void *data, u64 *val) 401 { 402 struct pci_ptm_debugfs *ptm_debugfs = data; 403 u64 clock; 404 int ret; 405 406 if (!ptm_debugfs->ops->t1_read) 407 return -EOPNOTSUPP; 408 409 ret = ptm_debugfs->ops->t1_read(ptm_debugfs->pdata, &clock); 410 if (ret) 411 return ret; 412 413 *val = clock; 414 415 return 0; 416 } 417 418 DEFINE_DEBUGFS_ATTRIBUTE(t1_fops, t1_get, NULL, "%llu\n"); 419 420 static int t2_get(void *data, u64 *val) 421 { 422 struct pci_ptm_debugfs *ptm_debugfs = data; 423 u64 clock; 424 int ret; 425 426 if (!ptm_debugfs->ops->t2_read) 427 return -EOPNOTSUPP; 428 429 ret = ptm_debugfs->ops->t2_read(ptm_debugfs->pdata, &clock); 430 if (ret) 431 return ret; 432 433 *val = clock; 434 435 return 0; 436 } 437 438 DEFINE_DEBUGFS_ATTRIBUTE(t2_fops, t2_get, NULL, "%llu\n"); 439 440 static int t3_get(void *data, u64 *val) 441 { 442 struct pci_ptm_debugfs *ptm_debugfs = data; 443 u64 clock; 444 int ret; 445 446 if (!ptm_debugfs->ops->t3_read) 447 return -EOPNOTSUPP; 448 449 ret = ptm_debugfs->ops->t3_read(ptm_debugfs->pdata, &clock); 450 if (ret) 451 return ret; 452 453 *val = clock; 454 455 return 0; 456 } 457 458 DEFINE_DEBUGFS_ATTRIBUTE(t3_fops, t3_get, NULL, "%llu\n"); 459 460 static int t4_get(void *data, u64 *val) 461 { 462 struct pci_ptm_debugfs *ptm_debugfs = data; 463 u64 clock; 464 int ret; 465 466 if (!ptm_debugfs->ops->t4_read) 467 return -EOPNOTSUPP; 468 469 ret = ptm_debugfs->ops->t4_read(ptm_debugfs->pdata, &clock); 470 if (ret) 471 return ret; 472 473 *val = clock; 474 475 return 0; 476 } 477 478 DEFINE_DEBUGFS_ATTRIBUTE(t4_fops, t4_get, NULL, "%llu\n"); 479 480 #define pcie_ptm_create_debugfs_file(pdata, mode, attr) \ 481 do { \ 482 if (ops->attr##_visible && ops->attr##_visible(pdata)) \ 483 debugfs_create_file(#attr, mode, ptm_debugfs->debugfs, \ 484 ptm_debugfs, &attr##_fops); \ 485 } while (0) 486 487 /* 488 * pcie_ptm_create_debugfs() - Create debugfs entries for the PTM context 489 * @dev: PTM capable component device 490 * @pdata: Private data of the PTM capable component device 491 * @ops: PTM callback structure 492 * 493 * Create debugfs entries for exposing the PTM context of the PTM capable 494 * components such as Root Complex and Endpoint controllers. 495 * 496 * Return: Pointer to 'struct pci_ptm_debugfs' if success, NULL otherwise. 497 */ 498 struct pci_ptm_debugfs *pcie_ptm_create_debugfs(struct device *dev, void *pdata, 499 const struct pcie_ptm_ops *ops) 500 { 501 struct pci_ptm_debugfs *ptm_debugfs; 502 char *dirname; 503 int ret; 504 505 /* Caller must provide check_capability() callback */ 506 if (!ops->check_capability) 507 return NULL; 508 509 /* Check for PTM capability before creating debugfs attrbutes */ 510 ret = ops->check_capability(pdata); 511 if (!ret) { 512 dev_dbg(dev, "PTM capability not present\n"); 513 return NULL; 514 } 515 516 ptm_debugfs = kzalloc(sizeof(*ptm_debugfs), GFP_KERNEL); 517 if (!ptm_debugfs) 518 return NULL; 519 520 dirname = devm_kasprintf(dev, GFP_KERNEL, "pcie_ptm_%s", dev_name(dev)); 521 if (!dirname) 522 return NULL; 523 524 ptm_debugfs->debugfs = debugfs_create_dir(dirname, NULL); 525 ptm_debugfs->pdata = pdata; 526 ptm_debugfs->ops = ops; 527 mutex_init(&ptm_debugfs->lock); 528 529 pcie_ptm_create_debugfs_file(pdata, 0644, context_update); 530 pcie_ptm_create_debugfs_file(pdata, 0644, context_valid); 531 pcie_ptm_create_debugfs_file(pdata, 0444, local_clock); 532 pcie_ptm_create_debugfs_file(pdata, 0444, master_clock); 533 pcie_ptm_create_debugfs_file(pdata, 0444, t1); 534 pcie_ptm_create_debugfs_file(pdata, 0444, t2); 535 pcie_ptm_create_debugfs_file(pdata, 0444, t3); 536 pcie_ptm_create_debugfs_file(pdata, 0444, t4); 537 538 return ptm_debugfs; 539 } 540 EXPORT_SYMBOL_GPL(pcie_ptm_create_debugfs); 541 542 /* 543 * pcie_ptm_destroy_debugfs() - Destroy debugfs entries for the PTM context 544 * @ptm_debugfs: Pointer to the PTM debugfs struct 545 */ 546 void pcie_ptm_destroy_debugfs(struct pci_ptm_debugfs *ptm_debugfs) 547 { 548 if (!ptm_debugfs) 549 return; 550 551 mutex_destroy(&ptm_debugfs->lock); 552 debugfs_remove_recursive(ptm_debugfs->debugfs); 553 } 554 EXPORT_SYMBOL_GPL(pcie_ptm_destroy_debugfs); 555