arch/powerpc/kernel/eeh_driver.c

   1 /*
   2  * PCI Error Recovery Driver for RPA-compliant PPC64 platform.
   3  * Copyright IBM Corp. 2004 2005
   4  * Copyright Linas Vepstas <[email protected]> 2004, 2005
   5  *
   6  * All rights reserved.
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or (at
  11  * your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful, but
  14  * WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
  16  * NON INFRINGEMENT.  See the GNU General Public License for more
  17  * details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  22  *
  23  * Send comments and feedback to Linas Vepstas <[email protected]>
  24  */
  25 #include <linux/delay.h>
  26 #include <linux/interrupt.h>
  27 #include <linux/irq.h>
  28 #include <linux/module.h>
  29 #include <linux/pci.h>
  30 #include <asm/eeh.h>
  31 #include <asm/eeh_event.h>
  32 #include <asm/ppc-pci.h>
  33 #include <asm/pci-bridge.h>
  34 #include <asm/prom.h>
  35 #include <asm/rtas.h>
  36
  37 struct eeh_rmv_data {
  38         struct list_head removed_vf_list;
  39         int removed_dev_count;
  40 };
  41
  42 static int eeh_result_priority(enum pci_ers_result result)
  43 {
  44         switch (result) {
  45         case PCI_ERS_RESULT_NONE:
  46                 return 1;
  47         case PCI_ERS_RESULT_NO_AER_DRIVER:
  48                 return 2;
  49         case PCI_ERS_RESULT_RECOVERED:
  50                 return 3;
  51         case PCI_ERS_RESULT_CAN_RECOVER:
  52                 return 4;
  53         case PCI_ERS_RESULT_DISCONNECT:
  54                 return 5;
  55         case PCI_ERS_RESULT_NEED_RESET:
  56                 return 6;
  57         default:
  58                 WARN_ONCE(1, "Unknown pci_ers_result value: %d\n", (int)result);
  59                 return 0;
  60         }
  61 };
  62
  63 static const char *pci_ers_result_name(enum pci_ers_result result)
  64 {
  65         switch (result) {
  66         case PCI_ERS_RESULT_NONE:
  67                 return "none";
  68         case PCI_ERS_RESULT_CAN_RECOVER:
  69                 return "can recover";
  70         case PCI_ERS_RESULT_NEED_RESET:
  71                 return "need reset";
  72         case PCI_ERS_RESULT_DISCONNECT:
  73                 return "disconnect";
  74         case PCI_ERS_RESULT_RECOVERED:
  75                 return "recovered";
  76         case PCI_ERS_RESULT_NO_AER_DRIVER:
  77                 return "no AER driver";
  78         default:
  79                 WARN_ONCE(1, "Unknown result type: %d\n", (int)result);
  80                 return "unknown";
  81         }
  82 };
  83
  84 static __printf(2, 3) void eeh_edev_info(const struct eeh_dev *edev,
  85                                          const char *fmt, ...)
  86 {
  87         struct va_format vaf;
  88         va_list args;
  89
  90         va_start(args, fmt);
  91
  92         vaf.fmt = fmt;
  93         vaf.va = &args;
  94
  95         printk(KERN_INFO "EEH: PE#%x (PCI %s): %pV\n", edev->pe_config_addr,
  96                edev->pdev ? dev_name(&edev->pdev->dev) : "none", &vaf);
  97
  98         va_end(args);
  99 }
 100
 101 static enum pci_ers_result pci_ers_merge_result(enum pci_ers_result old,
 102                                                 enum pci_ers_result new)
 103 {
 104         if (eeh_result_priority(new) > eeh_result_priority(old))
 105                 return new;
 106         return old;
 107 }
 108
 109 static bool eeh_dev_removed(struct eeh_dev *edev)
 110 {
 111         return !edev || (edev->mode & EEH_DEV_REMOVED);
 112 }
 113
 114 static bool eeh_edev_actionable(struct eeh_dev *edev)
 115 {
 116         return (edev->pdev && !eeh_dev_removed(edev) &&
 117                 !eeh_pe_passed(edev->pe));
 118 }
 119
 120 /**
 121  * eeh_pcid_get - Get the PCI device driver
 122  * @pdev: PCI device
 123  *
 124  * The function is used to retrieve the PCI device driver for
 125  * the indicated PCI device. Besides, we will increase the reference
 126  * of the PCI device driver to prevent that being unloaded on
 127  * the fly. Otherwise, kernel crash would be seen.
 128  */
 129 static inline struct pci_driver *eeh_pcid_get(struct pci_dev *pdev)
 130 {
 131         if (!pdev || !pdev->driver)
 132                 return NULL;
 133
 134         if (!try_module_get(pdev->driver->driver.owner))
 135                 return NULL;
 136
 137         return pdev->driver;
 138 }
 139
 140 /**
 141  * eeh_pcid_put - Dereference on the PCI device driver
 142  * @pdev: PCI device
 143  *
 144  * The function is called to do dereference on the PCI device
 145  * driver of the indicated PCI device.
 146  */
 147 static inline void eeh_pcid_put(struct pci_dev *pdev)
 148 {
 149         if (!pdev || !pdev->driver)
 150                 return;
 151
 152         module_put(pdev->driver->driver.owner);
 153 }
 154
 155 /**
 156  * eeh_disable_irq - Disable interrupt for the recovering device
 157  * @dev: PCI device
 158  *
 159  * This routine must be called when reporting temporary or permanent
 160  * error to the particular PCI device to disable interrupt of that
 161  * device. If the device has enabled MSI or MSI-X interrupt, we needn't
 162  * do real work because EEH should freeze DMA transfers for those PCI
 163  * devices encountering EEH errors, which includes MSI or MSI-X.
 164  */
 165 static void eeh_disable_irq(struct eeh_dev *edev)
 166 {
 167         /* Don't disable MSI and MSI-X interrupts. They are
 168          * effectively disabled by the DMA Stopped state
 169          * when an EEH error occurs.
 170          */
 171         if (edev->pdev->msi_enabled || edev->pdev->msix_enabled)
 172                 return;
 173
 174         if (!irq_has_action(edev->pdev->irq))
 175                 return;
 176
 177         edev->mode |= EEH_DEV_IRQ_DISABLED;
 178         disable_irq_nosync(edev->pdev->irq);
 179 }
 180
 181 /**
 182  * eeh_enable_irq - Enable interrupt for the recovering device
 183  * @dev: PCI device
 184  *
 185  * This routine must be called to enable interrupt while failed
 186  * device could be resumed.
 187  */
 188 static void eeh_enable_irq(struct eeh_dev *edev)
 189 {
 190         if ((edev->mode) & EEH_DEV_IRQ_DISABLED) {
 191                 edev->mode &= ~EEH_DEV_IRQ_DISABLED;
 192                 /*
 193                  * FIXME !!!!!
 194                  *
 195                  * This is just ass backwards. This maze has
 196                  * unbalanced irq_enable/disable calls. So instead of
 197                  * finding the root cause it works around the warning
 198                  * in the irq_enable code by conditionally calling
 199                  * into it.
 200                  *
 201                  * That's just wrong.The warning in the core code is
 202                  * there to tell people to fix their asymmetries in
 203                  * their own code, not by abusing the core information
 204                  * to avoid it.
 205                  *
 206                  * I so wish that the assymetry would be the other way
 207                  * round and a few more irq_disable calls render that
 208                  * shit unusable forever.
 209                  *
 210                  *      tglx
 211                  */
 212                 if (irqd_irq_disabled(irq_get_irq_data(edev->pdev->irq)))
 213                         enable_irq(edev->pdev->irq);
 214         }
 215 }
 216
 217 static void *eeh_dev_save_state(struct eeh_dev *edev, void *userdata)
 218 {
 219         struct pci_dev *pdev;
 220
 221         if (!edev)
 222                 return NULL;
 223
 224         /*
 225          * We cannot access the config space on some adapters.
 226          * Otherwise, it will cause fenced PHB. We don't save
 227          * the content in their config space and will restore
 228          * from the initial config space saved when the EEH
 229          * device is created.
 230          */
 231         if (edev->pe && (edev->pe->state & EEH_PE_CFG_RESTRICTED))
 232                 return NULL;
 233
 234         pdev = eeh_dev_to_pci_dev(edev);
 235         if (!pdev)
 236                 return NULL;
 237
 238         pci_save_state(pdev);
 239         return NULL;
 240 }
 241
 242 static void eeh_set_channel_state(struct eeh_pe *root, enum pci_channel_state s)
 243 {
 244         struct eeh_pe *pe;
 245         struct eeh_dev *edev, *tmp;
 246
 247         eeh_for_each_pe(root, pe)
 248                 eeh_pe_for_each_dev(pe, edev, tmp)
 249                         if (eeh_edev_actionable(edev))
 250                                 edev->pdev->error_state = s;
 251 }
 252
 253 static void eeh_set_irq_state(struct eeh_pe *root, bool enable)
 254 {
 255         struct eeh_pe *pe;
 256         struct eeh_dev *edev, *tmp;
 257
 258         eeh_for_each_pe(root, pe) {
 259                 eeh_pe_for_each_dev(pe, edev, tmp) {
 260                         if (!eeh_edev_actionable(edev))
 261                                 continue;
 262
 263                         if (!eeh_pcid_get(edev->pdev))
 264                                 continue;
 265
 266                         if (enable)
 267                                 eeh_enable_irq(edev);
 268                         else
 269                                 eeh_disable_irq(edev);
 270
 271                         eeh_pcid_put(edev->pdev);
 272                 }
 273         }
 274 }
 275
 276 typedef enum pci_ers_result (*eeh_report_fn)(struct eeh_dev *,
 277                                              struct pci_driver *);
 278 static void eeh_pe_report_edev(struct eeh_dev *edev, eeh_report_fn fn,
 279                                enum pci_ers_result *result)
 280 {
 281         struct pci_driver *driver;
 282         enum pci_ers_result new_result;
 283
 284         if (!edev->pdev) {
 285                 eeh_edev_info(edev, "no device");
 286                 return;
 287         }
 288         device_lock(&edev->pdev->dev);
 289         if (eeh_edev_actionable(edev)) {
 290                 driver = eeh_pcid_get(edev->pdev);
 291
 292                 if (!driver)
 293                         eeh_edev_info(edev, "no driver");
 294                 else if (!driver->err_handler)
 295                         eeh_edev_info(edev, "driver not EEH aware");
 296                 else if (edev->mode & EEH_DEV_NO_HANDLER)
 297                         eeh_edev_info(edev, "driver bound too late");
 298                 else {
 299                         new_result = fn(edev, driver);
 300                         eeh_edev_info(edev, "%s driver reports: '%s'",
 301                                       driver->name,
 302                                       pci_ers_result_name(new_result));
 303                         if (result)
 304                                 *result = pci_ers_merge_result(*result,
 305                                                                new_result);
 306                 }
 307                 if (driver)
 308                         eeh_pcid_put(edev->pdev);
 309         } else {
 310                 eeh_edev_info(edev, "not actionable (%d,%d,%d)", !!edev->pdev,
 311                               !eeh_dev_removed(edev), !eeh_pe_passed(edev->pe));
 312         }
 313         device_unlock(&edev->pdev->dev);
 314 }
 315
 316 static void eeh_pe_report(const char *name, struct eeh_pe *root,
 317                           eeh_report_fn fn, enum pci_ers_result *result)
 318 {
 319         struct eeh_pe *pe;
 320         struct eeh_dev *edev, *tmp;
 321
 322         pr_info("EEH: Beginning: '%s'\n", name);
 323         eeh_for_each_pe(root, pe) eeh_pe_for_each_dev(pe, edev, tmp)
 324                 eeh_pe_report_edev(edev, fn, result);
 325         if (result)
 326                 pr_info("EEH: Finished:'%s' with aggregate recovery state:'%s'\n",
 327                         name, pci_ers_result_name(*result));
 328         else
 329                 pr_info("EEH: Finished:'%s'", name);
 330 }
 331
 332 /**
 333  * eeh_report_error - Report pci error to each device driver
 334  * @edev: eeh device
 335  * @driver: device's PCI driver
 336  *
 337  * Report an EEH error to each device driver.
 338  */
 339 static enum pci_ers_result eeh_report_error(struct eeh_dev *edev,
 340                                             struct pci_driver *driver)
 341 {
 342         enum pci_ers_result rc;
 343         struct pci_dev *dev = edev->pdev;
 344
 345         if (!driver->err_handler->error_detected)
 346                 return PCI_ERS_RESULT_NONE;
 347
 348         eeh_edev_info(edev, "Invoking %s->error_detected(IO frozen)",
 349                       driver->name);
 350         rc = driver->err_handler->error_detected(dev, pci_channel_io_frozen);
 351
 352         edev->in_error = true;
 353         pci_uevent_ers(dev, PCI_ERS_RESULT_NONE);
 354         return rc;
 355 }
 356
 357 /**
 358  * eeh_report_mmio_enabled - Tell drivers that MMIO has been enabled
 359  * @edev: eeh device
 360  * @driver: device's PCI driver
 361  *
 362  * Tells each device driver that IO ports, MMIO and config space I/O
 363  * are now enabled.
 364  */
 365 static enum pci_ers_result eeh_report_mmio_enabled(struct eeh_dev *edev,
 366                                                    struct pci_driver *driver)
 367 {
 368         if (!driver->err_handler->mmio_enabled)
 369                 return PCI_ERS_RESULT_NONE;
 370         eeh_edev_info(edev, "Invoking %s->mmio_enabled()", driver->name);
 371         return driver->err_handler->mmio_enabled(edev->pdev);
 372 }
 373
 374 /**
 375  * eeh_report_reset - Tell device that slot has been reset
 376  * @edev: eeh device
 377  * @driver: device's PCI driver
 378  *
 379  * This routine must be called while EEH tries to reset particular
 380  * PCI device so that the associated PCI device driver could take
 381  * some actions, usually to save data the driver needs so that the
 382  * driver can work again while the device is recovered.
 383  */
 384 static enum pci_ers_result eeh_report_reset(struct eeh_dev *edev,
 385                                             struct pci_driver *driver)
 386 {
 387         if (!driver->err_handler->slot_reset || !edev->in_error)
 388                 return PCI_ERS_RESULT_NONE;
 389         eeh_edev_info(edev, "Invoking %s->slot_reset()", driver->name);
 390         return driver->err_handler->slot_reset(edev->pdev);
 391 }
 392
 393 static void *eeh_dev_restore_state(struct eeh_dev *edev, void *userdata)
 394 {
 395         struct pci_dev *pdev;
 396
 397         if (!edev)
 398                 return NULL;
 399
 400         /*
 401          * The content in the config space isn't saved because
 402          * the blocked config space on some adapters. We have
 403          * to restore the initial saved config space when the
 404          * EEH device is created.
 405          */
 406         if (edev->pe && (edev->pe->state & EEH_PE_CFG_RESTRICTED)) {
 407                 if (list_is_last(&edev->entry, &edev->pe->edevs))
 408                         eeh_pe_restore_bars(edev->pe);
 409
 410                 return NULL;
 411         }
 412
 413         pdev = eeh_dev_to_pci_dev(edev);
 414         if (!pdev)
 415                 return NULL;
 416
 417         pci_restore_state(pdev);
 418         return NULL;
 419 }
 420
 421 /**
 422  * eeh_report_resume - Tell device to resume normal operations
 423  * @edev: eeh device
 424  * @driver: device's PCI driver
 425  *
 426  * This routine must be called to notify the device driver that it
 427  * could resume so that the device driver can do some initialization
 428  * to make the recovered device work again.
 429  */
 430 static enum pci_ers_result eeh_report_resume(struct eeh_dev *edev,
 431                                              struct pci_driver *driver)
 432 {
 433         if (!driver->err_handler->resume || !edev->in_error)
 434                 return PCI_ERS_RESULT_NONE;
 435
 436         eeh_edev_info(edev, "Invoking %s->resume()", driver->name);
 437         driver->err_handler->resume(edev->pdev);
 438
 439         pci_uevent_ers(edev->pdev, PCI_ERS_RESULT_RECOVERED);
 440 #ifdef CONFIG_PCI_IOV
 441         if (eeh_ops->notify_resume && eeh_dev_to_pdn(edev))
 442                 eeh_ops->notify_resume(eeh_dev_to_pdn(edev));
 443 #endif
 444         return PCI_ERS_RESULT_NONE;
 445 }
 446
 447 /**
 448  * eeh_report_failure - Tell device driver that device is dead.
 449  * @edev: eeh device
 450  * @driver: device's PCI driver
 451  *
 452  * This informs the device driver that the device is permanently
 453  * dead, and that no further recovery attempts will be made on it.
 454  */
 455 static enum pci_ers_result eeh_report_failure(struct eeh_dev *edev,
 456                                               struct pci_driver *driver)
 457 {
 458         enum pci_ers_result rc;
 459
 460         if (!driver->err_handler->error_detected)
 461                 return PCI_ERS_RESULT_NONE;
 462
 463         eeh_edev_info(edev, "Invoking %s->error_detected(permanent failure)",
 464                       driver->name);
 465         rc = driver->err_handler->error_detected(edev->pdev,
 466                                                  pci_channel_io_perm_failure);
 467
 468         pci_uevent_ers(edev->pdev, PCI_ERS_RESULT_DISCONNECT);
 469         return rc;
 470 }
 471
 472 static void *eeh_add_virt_device(struct eeh_dev *edev)
 473 {
 474         struct pci_driver *driver;
 475         struct pci_dev *dev = eeh_dev_to_pci_dev(edev);
 476         struct pci_dn *pdn = eeh_dev_to_pdn(edev);
 477
 478         if (!(edev->physfn)) {
 479                 pr_warn("%s: EEH dev %04x:%02x:%02x.%01x not for VF\n",
 480                         __func__, pdn->phb->global_number, pdn->busno,
 481                         PCI_SLOT(pdn->devfn), PCI_FUNC(pdn->devfn));
 482                 return NULL;
 483         }
 484
 485         driver = eeh_pcid_get(dev);
 486         if (driver) {
 487                 if (driver->err_handler) {
 488                         eeh_pcid_put(dev);
 489                         return NULL;
 490                 }
 491                 eeh_pcid_put(dev);
 492         }
 493
 494 #ifdef CONFIG_PCI_IOV
 495         pci_iov_add_virtfn(edev->physfn, pdn->vf_index);
 496 #endif
 497         return NULL;
 498 }
 499
 500 static void *eeh_rmv_device(struct eeh_dev *edev, void *userdata)
 501 {
 502         struct pci_driver *driver;
 503         struct pci_dev *dev = eeh_dev_to_pci_dev(edev);
 504         struct eeh_rmv_data *rmv_data = (struct eeh_rmv_data *)userdata;
 505
 506         /*
 507          * Actually, we should remove the PCI bridges as well.
 508          * However, that's lots of complexity to do that,
 509          * particularly some of devices under the bridge might
 510          * support EEH. So we just care about PCI devices for
 511          * simplicity here.
 512          */
 513         if (!dev || (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE))
 514                 return NULL;
 515
 516         /*
 517          * We rely on count-based pcibios_release_device() to
 518          * detach permanently offlined PEs. Unfortunately, that's
 519          * not reliable enough. We might have the permanently
 520          * offlined PEs attached, but we needn't take care of
 521          * them and their child devices.
 522          */
 523         if (eeh_dev_removed(edev))
 524                 return NULL;
 525
 526         if (rmv_data) {
 527                 if (eeh_pe_passed(edev->pe))
 528                         return NULL;
 529                 driver = eeh_pcid_get(dev);
 530                 if (driver) {
 531                         if (driver->err_handler &&
 532                             driver->err_handler->error_detected &&
 533                             driver->err_handler->slot_reset) {
 534                                 eeh_pcid_put(dev);
 535                                 return NULL;
 536                         }
 537                         eeh_pcid_put(dev);
 538                 }
 539         }
 540
 541         /* Remove it from PCI subsystem */
 542         pr_debug("EEH: Removing %s without EEH sensitive driver\n",
 543                  pci_name(dev));
 544         edev->mode |= EEH_DEV_DISCONNECTED;
 545         if (rmv_data)
 546                 rmv_data->removed_dev_count++;
 547
 548         if (edev->physfn) {
 549 #ifdef CONFIG_PCI_IOV
 550                 struct pci_dn *pdn = eeh_dev_to_pdn(edev);
 551
 552                 pci_iov_remove_virtfn(edev->physfn, pdn->vf_index);
 553                 edev->pdev = NULL;
 554
 555                 /*
 556                  * We have to set the VF PE number to invalid one, which is
 557                  * required to plug the VF successfully.
 558                  */
 559                 pdn->pe_number = IODA_INVALID_PE;
 560 #endif
 561                 if (rmv_data)
 562                         list_add(&edev->rmv_entry, &rmv_data->removed_vf_list);
 563         } else {
 564                 pci_lock_rescan_remove();
 565                 pci_stop_and_remove_bus_device(dev);
 566                 pci_unlock_rescan_remove();
 567         }
 568
 569         return NULL;
 570 }
 571
 572 static void *eeh_pe_detach_dev(struct eeh_pe *pe, void *userdata)
 573 {
 574         struct eeh_dev *edev, *tmp;
 575
 576         eeh_pe_for_each_dev(pe, edev, tmp) {
 577                 if (!(edev->mode & EEH_DEV_DISCONNECTED))
 578                         continue;
 579
 580                 edev->mode &= ~(EEH_DEV_DISCONNECTED | EEH_DEV_IRQ_DISABLED);
 581                 eeh_rmv_from_parent_pe(edev);
 582         }
 583
 584         return NULL;
 585 }
 586
 587 /*
 588  * Explicitly clear PE's frozen state for PowerNV where
 589  * we have frozen PE until BAR restore is completed. It's
 590  * harmless to clear it for pSeries. To be consistent with
 591  * PE reset (for 3 times), we try to clear the frozen state
 592  * for 3 times as well.
 593  */
 594 static void *__eeh_clear_pe_frozen_state(struct eeh_pe *pe, void *flag)
 595 {
 596         bool clear_sw_state = *(bool *)flag;
 597         int i, rc = 1;
 598
 599         for (i = 0; rc && i < 3; i++)
 600                 rc = eeh_unfreeze_pe(pe, clear_sw_state);
 601
 602         /* Stop immediately on any errors */
 603         if (rc) {
 604                 pr_warn("%s: Failure %d unfreezing PHB#%x-PE#%x\n",
 605                         __func__, rc, pe->phb->global_number, pe->addr);
 606                 return (void *)pe;
 607         }
 608
 609         return NULL;
 610 }
 611
 612 static int eeh_clear_pe_frozen_state(struct eeh_pe *pe,
 613                                      bool clear_sw_state)
 614 {
 615         void *rc;
 616
 617         rc = eeh_pe_traverse(pe, __eeh_clear_pe_frozen_state, &clear_sw_state);
 618         if (!rc)
 619                 eeh_pe_state_clear(pe, EEH_PE_ISOLATED);
 620
 621         return rc ? -EIO : 0;
 622 }
 623
 624 int eeh_pe_reset_and_recover(struct eeh_pe *pe)
 625 {
 626         int ret;
 627
 628         /* Bail if the PE is being recovered */
 629         if (pe->state & EEH_PE_RECOVERING)
 630                 return 0;
 631
 632         /* Put the PE into recovery mode */
 633         eeh_pe_state_mark(pe, EEH_PE_RECOVERING);
 634
 635         /* Save states */
 636         eeh_pe_dev_traverse(pe, eeh_dev_save_state, NULL);
 637
 638         /* Issue reset */
 639         ret = eeh_pe_reset_full(pe);
 640         if (ret) {
 641                 eeh_pe_state_clear(pe, EEH_PE_RECOVERING);
 642                 return ret;
 643         }
 644
 645         /* Unfreeze the PE */
 646         ret = eeh_clear_pe_frozen_state(pe, true);
 647         if (ret) {
 648                 eeh_pe_state_clear(pe, EEH_PE_RECOVERING);
 649                 return ret;
 650         }
 651
 652         /* Restore device state */
 653         eeh_pe_dev_traverse(pe, eeh_dev_restore_state, NULL);
 654
 655         /* Clear recovery mode */
 656         eeh_pe_state_clear(pe, EEH_PE_RECOVERING);
 657
 658         return 0;
 659 }
 660
 661 /**
 662  * eeh_reset_device - Perform actual reset of a pci slot
 663  * @driver_eeh_aware: Does the device's driver provide EEH support?
 664  * @pe: EEH PE
 665  * @bus: PCI bus corresponding to the isolcated slot
 666  * @rmv_data: Optional, list to record removed devices
 667  *
 668  * This routine must be called to do reset on the indicated PE.
 669  * During the reset, udev might be invoked because those affected
 670  * PCI devices will be removed and then added.
 671  */
 672 static int eeh_reset_device(struct eeh_pe *pe, struct pci_bus *bus,
 673                             struct eeh_rmv_data *rmv_data,
 674                             bool driver_eeh_aware)
 675 {
 676         time64_t tstamp;
 677         int cnt, rc;
 678         struct eeh_dev *edev;
 679
 680         /* pcibios will clear the counter; save the value */
 681         cnt = pe->freeze_count;
 682         tstamp = pe->tstamp;
 683
 684         /*
 685          * We don't remove the corresponding PE instances because
 686          * we need the information afterwords. The attached EEH
 687          * devices are expected to be attached soon when calling
 688          * into pci_hp_add_devices().
 689          */
 690         eeh_pe_state_mark(pe, EEH_PE_KEEP);
 691         if (driver_eeh_aware || (pe->type & EEH_PE_VF)) {
 692                 eeh_pe_dev_traverse(pe, eeh_rmv_device, rmv_data);
 693         } else {
 694                 pci_lock_rescan_remove();
 695                 pci_hp_remove_devices(bus);
 696                 pci_unlock_rescan_remove();
 697         }
 698
 699         /*
 700          * Reset the pci controller. (Asserts RST#; resets config space).
 701          * Reconfigure bridges and devices. Don't try to bring the system
 702          * up if the reset failed for some reason.
 703          *
 704          * During the reset, it's very dangerous to have uncontrolled PCI
 705          * config accesses. So we prefer to block them. However, controlled
 706          * PCI config accesses initiated from EEH itself are allowed.
 707          */
 708         rc = eeh_pe_reset_full(pe);
 709         if (rc)
 710                 return rc;
 711
 712         pci_lock_rescan_remove();
 713
 714         /* Restore PE */
 715         eeh_ops->configure_bridge(pe);
 716         eeh_pe_restore_bars(pe);
 717
 718         /* Clear frozen state */
 719         rc = eeh_clear_pe_frozen_state(pe, false);
 720         if (rc) {
 721                 pci_unlock_rescan_remove();
 722                 return rc;
 723         }
 724
 725         /* Give the system 5 seconds to finish running the user-space
 726          * hotplug shutdown scripts, e.g. ifdown for ethernet.  Yes,
 727          * this is a hack, but if we don't do this, and try to bring
 728          * the device up before the scripts have taken it down,
 729          * potentially weird things happen.
 730          */
 731         if (!driver_eeh_aware || rmv_data->removed_dev_count) {
 732                 pr_info("EEH: Sleep 5s ahead of %s hotplug\n",
 733                         (driver_eeh_aware ? "partial" : "complete"));
 734                 ssleep(5);
 735
 736                 /*
 737                  * The EEH device is still connected with its parent
 738                  * PE. We should disconnect it so the binding can be
 739                  * rebuilt when adding PCI devices.
 740                  */
 741                 edev = list_first_entry(&pe->edevs, struct eeh_dev, entry);
 742                 eeh_pe_traverse(pe, eeh_pe_detach_dev, NULL);
 743                 if (pe->type & EEH_PE_VF) {
 744                         eeh_add_virt_device(edev);
 745                 } else {
 746                         if (!driver_eeh_aware)
 747                                 eeh_pe_state_clear(pe, EEH_PE_PRI_BUS);
 748                         pci_hp_add_devices(bus);
 749                 }
 750         }
 751         eeh_pe_state_clear(pe, EEH_PE_KEEP);
 752
 753         pe->tstamp = tstamp;
 754         pe->freeze_count = cnt;
 755
 756         pci_unlock_rescan_remove();
 757         return 0;
 758 }
 759
 760 /* The longest amount of time to wait for a pci device
 761  * to come back on line, in seconds.
 762  */
 763 #define MAX_WAIT_FOR_RECOVERY 300
 764
 765 /**
 766  * eeh_handle_normal_event - Handle EEH events on a specific PE
 767  * @pe: EEH PE - which should not be used after we return, as it may
 768  * have been invalidated.
 769  *
 770  * Attempts to recover the given PE.  If recovery fails or the PE has failed
 771  * too many times, remove the PE.
 772  *
 773  * While PHB detects address or data parity errors on particular PCI
 774  * slot, the associated PE will be frozen. Besides, DMA's occurring
 775  * to wild addresses (which usually happen due to bugs in device
 776  * drivers or in PCI adapter firmware) can cause EEH error. #SERR,
 777  * #PERR or other misc PCI-related errors also can trigger EEH errors.
 778  *
 779  * Recovery process consists of unplugging the device driver (which
 780  * generated hotplug events to userspace), then issuing a PCI #RST to
 781  * the device, then reconfiguring the PCI config space for all bridges
 782  * & devices under this slot, and then finally restarting the device
 783  * drivers (which cause a second set of hotplug events to go out to
 784  * userspace).
 785  */
 786 void eeh_handle_normal_event(struct eeh_pe *pe)
 787 {
 788         struct pci_bus *bus;
 789         struct eeh_dev *edev, *tmp;
 790         struct eeh_pe *tmp_pe;
 791         int rc = 0;
 792         enum pci_ers_result result = PCI_ERS_RESULT_NONE;
 793         struct eeh_rmv_data rmv_data =
 794                 {LIST_HEAD_INIT(rmv_data.removed_vf_list), 0};
 795
 796         bus = eeh_pe_bus_get(pe);
 797         if (!bus) {
 798                 pr_err("%s: Cannot find PCI bus for PHB#%x-PE#%x\n",
 799                         __func__, pe->phb->global_number, pe->addr);
 800                 return;
 801         }
 802
 803         eeh_pe_state_mark(pe, EEH_PE_RECOVERING);
 804
 805         eeh_pe_update_time_stamp(pe);
 806         pe->freeze_count++;
 807         if (pe->freeze_count > eeh_max_freezes) {
 808                 pr_err("EEH: PHB#%x-PE#%x has failed %d times in the last hour and has been permanently disabled.\n",
 809                        pe->phb->global_number, pe->addr,
 810                        pe->freeze_count);
 811                 result = PCI_ERS_RESULT_DISCONNECT;
 812         }
 813
 814         /* Walk the various device drivers attached to this slot through
 815          * a reset sequence, giving each an opportunity to do what it needs
 816          * to accomplish the reset.  Each child gets a report of the
 817          * status ... if any child can't handle the reset, then the entire
 818          * slot is dlpar removed and added.
 819          *
 820          * When the PHB is fenced, we have to issue a reset to recover from
 821          * the error. Override the result if necessary to have partially
 822          * hotplug for this case.
 823          */
 824         if (result != PCI_ERS_RESULT_DISCONNECT) {
 825                 pr_warn("EEH: This PCI device has failed %d times in the last hour and will be permanently disabled after %d failures.\n",
 826                         pe->freeze_count, eeh_max_freezes);
 827                 pr_info("EEH: Notify device drivers to shutdown\n");
 828                 eeh_set_channel_state(pe, pci_channel_io_frozen);
 829                 eeh_set_irq_state(pe, false);
 830                 eeh_pe_report("error_detected(IO frozen)", pe,
 831                               eeh_report_error, &result);
 832                 if ((pe->type & EEH_PE_PHB) &&
 833                     result != PCI_ERS_RESULT_NONE &&
 834                     result != PCI_ERS_RESULT_NEED_RESET)
 835                         result = PCI_ERS_RESULT_NEED_RESET;
 836         }
 837
 838         /* Get the current PCI slot state. This can take a long time,
 839          * sometimes over 300 seconds for certain systems.
 840          */
 841         if (result != PCI_ERS_RESULT_DISCONNECT) {
 842                 rc = eeh_wait_state(pe, MAX_WAIT_FOR_RECOVERY*1000);
 843                 if (rc < 0 || rc == EEH_STATE_NOT_SUPPORT) {
 844                         pr_warn("EEH: Permanent failure\n");
 845                         result = PCI_ERS_RESULT_DISCONNECT;
 846                 }
 847         }
 848
 849         /* Since rtas may enable MMIO when posting the error log,
 850          * don't post the error log until after all dev drivers
 851          * have been informed.
 852          */
 853         if (result != PCI_ERS_RESULT_DISCONNECT) {
 854                 pr_info("EEH: Collect temporary log\n");
 855                 eeh_slot_error_detail(pe, EEH_LOG_TEMP);
 856         }
 857
 858         /* If all device drivers were EEH-unaware, then shut
 859          * down all of the device drivers, and hope they
 860          * go down willingly, without panicing the system.
 861          */
 862         if (result == PCI_ERS_RESULT_NONE) {
 863                 pr_info("EEH: Reset with hotplug activity\n");
 864                 rc = eeh_reset_device(pe, bus, NULL, false);
 865                 if (rc) {
 866                         pr_warn("%s: Unable to reset, err=%d\n",
 867                                 __func__, rc);
 868                         result = PCI_ERS_RESULT_DISCONNECT;
 869                 }
 870         }
 871
 872         /* If all devices reported they can proceed, then re-enable MMIO */
 873         if (result == PCI_ERS_RESULT_CAN_RECOVER) {
 874                 pr_info("EEH: Enable I/O for affected devices\n");
 875                 rc = eeh_pci_enable(pe, EEH_OPT_THAW_MMIO);
 876
 877                 if (rc < 0) {
 878                         result = PCI_ERS_RESULT_DISCONNECT;
 879                 } else if (rc) {
 880                         result = PCI_ERS_RESULT_NEED_RESET;
 881                 } else {
 882                         pr_info("EEH: Notify device drivers to resume I/O\n");
 883                         eeh_pe_report("mmio_enabled", pe,
 884                                       eeh_report_mmio_enabled, &result);
 885                 }
 886         }
 887
 888         /* If all devices reported they can proceed, then re-enable DMA */
 889         if (result == PCI_ERS_RESULT_CAN_RECOVER) {
 890                 pr_info("EEH: Enabled DMA for affected devices\n");
 891                 rc = eeh_pci_enable(pe, EEH_OPT_THAW_DMA);
 892
 893                 if (rc < 0) {
 894                         result = PCI_ERS_RESULT_DISCONNECT;
 895                 } else if (rc) {
 896                         result = PCI_ERS_RESULT_NEED_RESET;
 897                 } else {
 898                         /*
 899                          * We didn't do PE reset for the case. The PE
 900                          * is still in frozen state. Clear it before
 901                          * resuming the PE.
 902                          */
 903                         eeh_pe_state_clear(pe, EEH_PE_ISOLATED);
 904                         result = PCI_ERS_RESULT_RECOVERED;
 905                 }
 906         }
 907
 908         /* If any device called out for a reset, then reset the slot */
 909         if (result == PCI_ERS_RESULT_NEED_RESET) {
 910                 pr_info("EEH: Reset without hotplug activity\n");
 911                 rc = eeh_reset_device(pe, bus, &rmv_data, true);
 912                 if (rc) {
 913                         pr_warn("%s: Cannot reset, err=%d\n",
 914                                 __func__, rc);
 915                         result = PCI_ERS_RESULT_DISCONNECT;
 916                 } else {
 917                         result = PCI_ERS_RESULT_NONE;
 918                         eeh_set_channel_state(pe, pci_channel_io_normal);
 919                         eeh_set_irq_state(pe, true);
 920                         eeh_pe_report("slot_reset", pe, eeh_report_reset,
 921                                       &result);
 922                 }
 923         }
 924
 925         if ((result == PCI_ERS_RESULT_RECOVERED) ||
 926             (result == PCI_ERS_RESULT_NONE)) {
 927                 /*
 928                  * For those hot removed VFs, we should add back them after PF
 929                  * get recovered properly.
 930                  */
 931                 list_for_each_entry_safe(edev, tmp, &rmv_data.removed_vf_list,
 932                                          rmv_entry) {
 933                         eeh_add_virt_device(edev);
 934                         list_del(&edev->rmv_entry);
 935                 }
 936
 937                 /* Tell all device drivers that they can resume operations */
 938                 pr_info("EEH: Notify device driver to resume\n");
 939                 eeh_set_channel_state(pe, pci_channel_io_normal);
 940                 eeh_set_irq_state(pe, true);
 941                 eeh_pe_report("resume", pe, eeh_report_resume, NULL);
 942                 eeh_for_each_pe(pe, tmp_pe) {
 943                         eeh_pe_for_each_dev(tmp_pe, edev, tmp) {
 944                                 edev->mode &= ~EEH_DEV_NO_HANDLER;
 945                                 edev->in_error = false;
 946                         }
 947                 }
 948
 949                 pr_info("EEH: Recovery successful.\n");
 950         } else  {
 951                 /*
 952                  * About 90% of all real-life EEH failures in the field
 953                  * are due to poorly seated PCI cards. Only 10% or so are
 954                  * due to actual, failed cards.
 955                  */
 956                 pr_err("EEH: Unable to recover from failure from PHB#%x-PE#%x.\n"
 957                        "Please try reseating or replacing it\n",
 958                         pe->phb->global_number, pe->addr);
 959
 960                 eeh_slot_error_detail(pe, EEH_LOG_PERM);
 961
 962                 /* Notify all devices that they're about to go down. */
 963                 eeh_set_channel_state(pe, pci_channel_io_perm_failure);
 964                 eeh_set_irq_state(pe, false);
 965                 eeh_pe_report("error_detected(permanent failure)", pe,
 966                               eeh_report_failure, NULL);
 967
 968                 /* Mark the PE to be removed permanently */
 969                 eeh_pe_state_mark(pe, EEH_PE_REMOVED);
 970
 971                 /*
 972                  * Shut down the device drivers for good. We mark
 973                  * all removed devices correctly to avoid access
 974                  * the their PCI config any more.
 975                  */
 976                 if (pe->type & EEH_PE_VF) {
 977                         eeh_pe_dev_traverse(pe, eeh_rmv_device, NULL);
 978                         eeh_pe_dev_mode_mark(pe, EEH_DEV_REMOVED);
 979                 } else {
 980                         eeh_pe_state_clear(pe, EEH_PE_PRI_BUS);
 981                         eeh_pe_dev_mode_mark(pe, EEH_DEV_REMOVED);
 982
 983                         pci_lock_rescan_remove();
 984                         pci_hp_remove_devices(bus);
 985                         pci_unlock_rescan_remove();
 986                         /* The passed PE should no longer be used */
 987                         return;
 988                 }
 989         }
 990         eeh_pe_state_clear(pe, EEH_PE_RECOVERING);
 991 }
 992
 993 /**
 994  * eeh_handle_special_event - Handle EEH events without a specific failing PE
 995  *
 996  * Called when an EEH event is detected but can't be narrowed down to a
 997  * specific PE.  Iterates through possible failures and handles them as
 998  * necessary.
 999  */
1000 void eeh_handle_special_event(void)
1001 {
1002         struct eeh_pe *pe, *phb_pe;
1003         struct pci_bus *bus;
1004         struct pci_controller *hose;
1005         unsigned long flags;
1006         int rc;
1007
1008
1009         do {
1010                 rc = eeh_ops->next_error(&pe);
1011
1012                 switch (rc) {
1013                 case EEH_NEXT_ERR_DEAD_IOC:
1014                         /* Mark all PHBs in dead state */
1015                         eeh_serialize_lock(&flags);
1016
1017                         /* Purge all events */
1018                         eeh_remove_event(NULL, true);
1019
1020                         list_for_each_entry(hose, &hose_list, list_node) {
1021                                 phb_pe = eeh_phb_pe_get(hose);
1022                                 if (!phb_pe) continue;
1023
1024                                 eeh_pe_mark_isolated(phb_pe);
1025                         }
1026
1027                         eeh_serialize_unlock(flags);
1028
1029                         break;
1030                 case EEH_NEXT_ERR_FROZEN_PE:
1031                 case EEH_NEXT_ERR_FENCED_PHB:
1032                 case EEH_NEXT_ERR_DEAD_PHB:
1033                         /* Mark the PE in fenced state */
1034                         eeh_serialize_lock(&flags);
1035
1036                         /* Purge all events of the PHB */
1037                         eeh_remove_event(pe, true);
1038
1039                         if (rc != EEH_NEXT_ERR_DEAD_PHB)
1040                                 eeh_pe_state_mark(pe, EEH_PE_RECOVERING);
1041                         eeh_pe_mark_isolated(pe);
1042
1043                         eeh_serialize_unlock(flags);
1044
1045                         break;
1046                 case EEH_NEXT_ERR_NONE:
1047                         return;
1048                 default:
1049                         pr_warn("%s: Invalid value %d from next_error()\n",
1050                                 __func__, rc);
1051                         return;
1052                 }
1053
1054                 /*
1055                  * For fenced PHB and frozen PE, it's handled as normal
1056                  * event. We have to remove the affected PHBs for dead
1057                  * PHB and IOC
1058                  */
1059                 if (rc == EEH_NEXT_ERR_FROZEN_PE ||
1060                     rc == EEH_NEXT_ERR_FENCED_PHB) {
1061                         eeh_handle_normal_event(pe);
1062                 } else {
1063                         pci_lock_rescan_remove();
1064                         list_for_each_entry(hose, &hose_list, list_node) {
1065                                 phb_pe = eeh_phb_pe_get(hose);
1066                                 if (!phb_pe ||
1067                                     !(phb_pe->state & EEH_PE_ISOLATED) ||
1068                                     (phb_pe->state & EEH_PE_RECOVERING))
1069                                         continue;
1070
1071                                 /* Notify all devices to be down */
1072                                 eeh_pe_state_clear(pe, EEH_PE_PRI_BUS);
1073                                 eeh_set_channel_state(pe, pci_channel_io_perm_failure);
1074                                 eeh_pe_report(
1075                                         "error_detected(permanent failure)", pe,
1076                                         eeh_report_failure, NULL);
1077                                 bus = eeh_pe_bus_get(phb_pe);
1078                                 if (!bus) {
1079                                         pr_err("%s: Cannot find PCI bus for "
1080                                                "PHB#%x-PE#%x\n",
1081                                                __func__,
1082                                                pe->phb->global_number,
1083                                                pe->addr);
1084                                         break;
1085                                 }
1086                                 pci_hp_remove_devices(bus);
1087                         }
1088                         pci_unlock_rescan_remove();
1089                 }
1090
1091                 /*
1092                  * If we have detected dead IOC, we needn't proceed
1093                  * any more since all PHBs would have been removed
1094                  */
1095                 if (rc == EEH_NEXT_ERR_DEAD_IOC)
1096                         break;
1097         } while (rc != EEH_NEXT_ERR_NONE);
1098 }