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 <linas@linas.org> 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 <linas@austin.ibm.com>
  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 /**
  38  * eeh_pcid_name - Retrieve name of PCI device driver
  39  * @pdev: PCI device
  40  *
  41  * This routine is used to retrieve the name of PCI device driver
  42  * if that's valid.
  43  */
  44 static inline const char *eeh_pcid_name(struct pci_dev *pdev)
  45 {
  46         if (pdev && pdev->dev.driver)
  47                 return pdev->dev.driver->name;
  48         return "";
  49 }
  50
  51 /**
  52  * eeh_pcid_get - Get the PCI device driver
  53  * @pdev: PCI device
  54  *
  55  * The function is used to retrieve the PCI device driver for
  56  * the indicated PCI device. Besides, we will increase the reference
  57  * of the PCI device driver to prevent that being unloaded on
  58  * the fly. Otherwise, kernel crash would be seen.
  59  */
  60 static inline struct pci_driver *eeh_pcid_get(struct pci_dev *pdev)
  61 {
  62         if (!pdev || !pdev->driver)
  63                 return NULL;
  64
  65         if (!try_module_get(pdev->driver->driver.owner))
  66                 return NULL;
  67
  68         return pdev->driver;
  69 }
  70
  71 /**
  72  * eeh_pcid_put - Dereference on the PCI device driver
  73  * @pdev: PCI device
  74  *
  75  * The function is called to do dereference on the PCI device
  76  * driver of the indicated PCI device.
  77  */
  78 static inline void eeh_pcid_put(struct pci_dev *pdev)
  79 {
  80         if (!pdev || !pdev->driver)
  81                 return;
  82
  83         module_put(pdev->driver->driver.owner);
  84 }
  85
  86 /**
  87  * eeh_disable_irq - Disable interrupt for the recovering device
  88  * @dev: PCI device
  89  *
  90  * This routine must be called when reporting temporary or permanent
  91  * error to the particular PCI device to disable interrupt of that
  92  * device. If the device has enabled MSI or MSI-X interrupt, we needn't
  93  * do real work because EEH should freeze DMA transfers for those PCI
  94  * devices encountering EEH errors, which includes MSI or MSI-X.
  95  */
  96 static void eeh_disable_irq(struct pci_dev *dev)
  97 {
  98         struct eeh_dev *edev = pci_dev_to_eeh_dev(dev);
  99
 100         /* Don't disable MSI and MSI-X interrupts. They are
 101          * effectively disabled by the DMA Stopped state
 102          * when an EEH error occurs.
 103          */
 104         if (dev->msi_enabled || dev->msix_enabled)
 105                 return;
 106
 107         if (!irq_has_action(dev->irq))
 108                 return;
 109
 110         edev->mode |= EEH_DEV_IRQ_DISABLED;
 111         disable_irq_nosync(dev->irq);
 112 }
 113
 114 /**
 115  * eeh_enable_irq - Enable interrupt for the recovering device
 116  * @dev: PCI device
 117  *
 118  * This routine must be called to enable interrupt while failed
 119  * device could be resumed.
 120  */
 121 static void eeh_enable_irq(struct pci_dev *dev)
 122 {
 123         struct eeh_dev *edev = pci_dev_to_eeh_dev(dev);
 124
 125         if ((edev->mode) & EEH_DEV_IRQ_DISABLED) {
 126                 edev->mode &= ~EEH_DEV_IRQ_DISABLED;
 127                 /*
 128                  * FIXME !!!!!
 129                  *
 130                  * This is just ass backwards. This maze has
 131                  * unbalanced irq_enable/disable calls. So instead of
 132                  * finding the root cause it works around the warning
 133                  * in the irq_enable code by conditionally calling
 134                  * into it.
 135                  *
 136                  * That's just wrong.The warning in the core code is
 137                  * there to tell people to fix their assymetries in
 138                  * their own code, not by abusing the core information
 139                  * to avoid it.
 140                  *
 141                  * I so wish that the assymetry would be the other way
 142                  * round and a few more irq_disable calls render that
 143                  * shit unusable forever.
 144                  *
 145                  *      tglx
 146                  */
 147                 if (irqd_irq_disabled(irq_get_irq_data(dev->irq)))
 148                         enable_irq(dev->irq);
 149         }
 150 }
 151
 152 static bool eeh_dev_removed(struct eeh_dev *edev)
 153 {
 154         /* EEH device removed ? */
 155         if (!edev || (edev->mode & EEH_DEV_REMOVED))
 156                 return true;
 157
 158         return false;
 159 }
 160
 161 static void *eeh_dev_save_state(void *data, void *userdata)
 162 {
 163         struct eeh_dev *edev = data;
 164         struct pci_dev *pdev;
 165
 166         if (!edev)
 167                 return NULL;
 168
 169         /*
 170          * We cannot access the config space on some adapters.
 171          * Otherwise, it will cause fenced PHB. We don't save
 172          * the content in their config space and will restore
 173          * from the initial config space saved when the EEH
 174          * device is created.
 175          */
 176         if (edev->pe && (edev->pe->state & EEH_PE_CFG_RESTRICTED))
 177                 return NULL;
 178
 179         pdev = eeh_dev_to_pci_dev(edev);
 180         if (!pdev)
 181                 return NULL;
 182
 183         pci_save_state(pdev);
 184         return NULL;
 185 }
 186
 187 /**
 188  * eeh_report_error - Report pci error to each device driver
 189  * @data: eeh device
 190  * @userdata: return value
 191  *
 192  * Report an EEH error to each device driver, collect up and
 193  * merge the device driver responses. Cumulative response
 194  * passed back in "userdata".
 195  */
 196 static void *eeh_report_error(void *data, void *userdata)
 197 {
 198         struct eeh_dev *edev = (struct eeh_dev *)data;
 199         struct pci_dev *dev = eeh_dev_to_pci_dev(edev);
 200         enum pci_ers_result rc, *res = userdata;
 201         struct pci_driver *driver;
 202
 203         if (!dev || eeh_dev_removed(edev))
 204                 return NULL;
 205         dev->error_state = pci_channel_io_frozen;
 206
 207         driver = eeh_pcid_get(dev);
 208         if (!driver) return NULL;
 209
 210         eeh_disable_irq(dev);
 211
 212         if (!driver->err_handler ||
 213             !driver->err_handler->error_detected) {
 214                 eeh_pcid_put(dev);
 215                 return NULL;
 216         }
 217
 218         rc = driver->err_handler->error_detected(dev, pci_channel_io_frozen);
 219
 220         /* A driver that needs a reset trumps all others */
 221         if (rc == PCI_ERS_RESULT_NEED_RESET) *res = rc;
 222         if (*res == PCI_ERS_RESULT_NONE) *res = rc;
 223
 224         eeh_pcid_put(dev);
 225         return NULL;
 226 }
 227
 228 /**
 229  * eeh_report_mmio_enabled - Tell drivers that MMIO has been enabled
 230  * @data: eeh device
 231  * @userdata: return value
 232  *
 233  * Tells each device driver that IO ports, MMIO and config space I/O
 234  * are now enabled. Collects up and merges the device driver responses.
 235  * Cumulative response passed back in "userdata".
 236  */
 237 static void *eeh_report_mmio_enabled(void *data, void *userdata)
 238 {
 239         struct eeh_dev *edev = (struct eeh_dev *)data;
 240         struct pci_dev *dev = eeh_dev_to_pci_dev(edev);
 241         enum pci_ers_result rc, *res = userdata;
 242         struct pci_driver *driver;
 243
 244         if (!dev || eeh_dev_removed(edev))
 245                 return NULL;
 246
 247         driver = eeh_pcid_get(dev);
 248         if (!driver) return NULL;
 249
 250         if (!driver->err_handler ||
 251             !driver->err_handler->mmio_enabled ||
 252             (edev->mode & EEH_DEV_NO_HANDLER)) {
 253                 eeh_pcid_put(dev);
 254                 return NULL;
 255         }
 256
 257         rc = driver->err_handler->mmio_enabled(dev);
 258
 259         /* A driver that needs a reset trumps all others */
 260         if (rc == PCI_ERS_RESULT_NEED_RESET) *res = rc;
 261         if (*res == PCI_ERS_RESULT_NONE) *res = rc;
 262
 263         eeh_pcid_put(dev);
 264         return NULL;
 265 }
 266
 267 /**
 268  * eeh_report_reset - Tell device that slot has been reset
 269  * @data: eeh device
 270  * @userdata: return value
 271  *
 272  * This routine must be called while EEH tries to reset particular
 273  * PCI device so that the associated PCI device driver could take
 274  * some actions, usually to save data the driver needs so that the
 275  * driver can work again while the device is recovered.
 276  */
 277 static void *eeh_report_reset(void *data, void *userdata)
 278 {
 279         struct eeh_dev *edev = (struct eeh_dev *)data;
 280         struct pci_dev *dev = eeh_dev_to_pci_dev(edev);
 281         enum pci_ers_result rc, *res = userdata;
 282         struct pci_driver *driver;
 283
 284         if (!dev || eeh_dev_removed(edev))
 285                 return NULL;
 286         dev->error_state = pci_channel_io_normal;
 287
 288         driver = eeh_pcid_get(dev);
 289         if (!driver) return NULL;
 290
 291         eeh_enable_irq(dev);
 292
 293         if (!driver->err_handler ||
 294             !driver->err_handler->slot_reset ||
 295             (edev->mode & EEH_DEV_NO_HANDLER)) {
 296                 eeh_pcid_put(dev);
 297                 return NULL;
 298         }
 299
 300         rc = driver->err_handler->slot_reset(dev);
 301         if ((*res == PCI_ERS_RESULT_NONE) ||
 302             (*res == PCI_ERS_RESULT_RECOVERED)) *res = rc;
 303         if (*res == PCI_ERS_RESULT_DISCONNECT &&
 304              rc == PCI_ERS_RESULT_NEED_RESET) *res = rc;
 305
 306         eeh_pcid_put(dev);
 307         return NULL;
 308 }
 309
 310 static void *eeh_dev_restore_state(void *data, void *userdata)
 311 {
 312         struct eeh_dev *edev = data;
 313         struct pci_dev *pdev;
 314
 315         if (!edev)
 316                 return NULL;
 317
 318         /*
 319          * The content in the config space isn't saved because
 320          * the blocked config space on some adapters. We have
 321          * to restore the initial saved config space when the
 322          * EEH device is created.
 323          */
 324         if (edev->pe && (edev->pe->state & EEH_PE_CFG_RESTRICTED)) {
 325                 if (list_is_last(&edev->list, &edev->pe->edevs))
 326                         eeh_pe_restore_bars(edev->pe);
 327
 328                 return NULL;
 329         }
 330
 331         pdev = eeh_dev_to_pci_dev(edev);
 332         if (!pdev)
 333                 return NULL;
 334
 335         pci_restore_state(pdev);
 336         return NULL;
 337 }
 338
 339 /**
 340  * eeh_report_resume - Tell device to resume normal operations
 341  * @data: eeh device
 342  * @userdata: return value
 343  *
 344  * This routine must be called to notify the device driver that it
 345  * could resume so that the device driver can do some initialization
 346  * to make the recovered device work again.
 347  */
 348 static void *eeh_report_resume(void *data, void *userdata)
 349 {
 350         struct eeh_dev *edev = (struct eeh_dev *)data;
 351         struct pci_dev *dev = eeh_dev_to_pci_dev(edev);
 352         struct pci_driver *driver;
 353
 354         if (!dev || eeh_dev_removed(edev))
 355                 return NULL;
 356         dev->error_state = pci_channel_io_normal;
 357
 358         driver = eeh_pcid_get(dev);
 359         if (!driver) return NULL;
 360
 361         eeh_enable_irq(dev);
 362
 363         if (!driver->err_handler ||
 364             !driver->err_handler->resume ||
 365             (edev->mode & EEH_DEV_NO_HANDLER)) {
 366                 edev->mode &= ~EEH_DEV_NO_HANDLER;
 367                 eeh_pcid_put(dev);
 368                 return NULL;
 369         }
 370
 371         driver->err_handler->resume(dev);
 372
 373         eeh_pcid_put(dev);
 374         return NULL;
 375 }
 376
 377 /**
 378  * eeh_report_failure - Tell device driver that device is dead.
 379  * @data: eeh device
 380  * @userdata: return value
 381  *
 382  * This informs the device driver that the device is permanently
 383  * dead, and that no further recovery attempts will be made on it.
 384  */
 385 static void *eeh_report_failure(void *data, void *userdata)
 386 {
 387         struct eeh_dev *edev = (struct eeh_dev *)data;
 388         struct pci_dev *dev = eeh_dev_to_pci_dev(edev);
 389         struct pci_driver *driver;
 390
 391         if (!dev || eeh_dev_removed(edev))
 392                 return NULL;
 393         dev->error_state = pci_channel_io_perm_failure;
 394
 395         driver = eeh_pcid_get(dev);
 396         if (!driver) return NULL;
 397
 398         eeh_disable_irq(dev);
 399
 400         if (!driver->err_handler ||
 401             !driver->err_handler->error_detected) {
 402                 eeh_pcid_put(dev);
 403                 return NULL;
 404         }
 405
 406         driver->err_handler->error_detected(dev, pci_channel_io_perm_failure);
 407
 408         eeh_pcid_put(dev);
 409         return NULL;
 410 }
 411
 412 static void *eeh_rmv_device(void *data, void *userdata)
 413 {
 414         struct pci_driver *driver;
 415         struct eeh_dev *edev = (struct eeh_dev *)data;
 416         struct pci_dev *dev = eeh_dev_to_pci_dev(edev);
 417         int *removed = (int *)userdata;
 418
 419         /*
 420          * Actually, we should remove the PCI bridges as well.
 421          * However, that's lots of complexity to do that,
 422          * particularly some of devices under the bridge might
 423          * support EEH. So we just care about PCI devices for
 424          * simplicity here.
 425          */
 426         if (!dev || (dev->hdr_type & PCI_HEADER_TYPE_BRIDGE))
 427                 return NULL;
 428
 429         /*
 430          * We rely on count-based pcibios_release_device() to
 431          * detach permanently offlined PEs. Unfortunately, that's
 432          * not reliable enough. We might have the permanently
 433          * offlined PEs attached, but we needn't take care of
 434          * them and their child devices.
 435          */
 436         if (eeh_dev_removed(edev))
 437                 return NULL;
 438
 439         driver = eeh_pcid_get(dev);
 440         if (driver) {
 441                 eeh_pcid_put(dev);
 442                 if (driver->err_handler &&
 443                     driver->err_handler->error_detected &&
 444                     driver->err_handler->slot_reset)
 445                         return NULL;
 446         }
 447
 448         /* Remove it from PCI subsystem */
 449         pr_debug("EEH: Removing %s without EEH sensitive driver\n",
 450                  pci_name(dev));
 451         edev->bus = dev->bus;
 452         edev->mode |= EEH_DEV_DISCONNECTED;
 453         (*removed)++;
 454
 455         pci_lock_rescan_remove();
 456         pci_stop_and_remove_bus_device(dev);
 457         pci_unlock_rescan_remove();
 458
 459         return NULL;
 460 }
 461
 462 static void *eeh_pe_detach_dev(void *data, void *userdata)
 463 {
 464         struct eeh_pe *pe = (struct eeh_pe *)data;
 465         struct eeh_dev *edev, *tmp;
 466
 467         eeh_pe_for_each_dev(pe, edev, tmp) {
 468                 if (!(edev->mode & EEH_DEV_DISCONNECTED))
 469                         continue;
 470
 471                 edev->mode &= ~(EEH_DEV_DISCONNECTED | EEH_DEV_IRQ_DISABLED);
 472                 eeh_rmv_from_parent_pe(edev);
 473         }
 474
 475         return NULL;
 476 }
 477
 478 /*
 479  * Explicitly clear PE's frozen state for PowerNV where
 480  * we have frozen PE until BAR restore is completed. It's
 481  * harmless to clear it for pSeries. To be consistent with
 482  * PE reset (for 3 times), we try to clear the frozen state
 483  * for 3 times as well.
 484  */
 485 static void *__eeh_clear_pe_frozen_state(void *data, void *flag)
 486 {
 487         struct eeh_pe *pe = (struct eeh_pe *)data;
 488         bool *clear_sw_state = flag;
 489         int i, rc = 1;
 490
 491         for (i = 0; rc && i < 3; i++)
 492                 rc = eeh_unfreeze_pe(pe, clear_sw_state);
 493
 494         /* Stop immediately on any errors */
 495         if (rc) {
 496                 pr_warn("%s: Failure %d unfreezing PHB#%x-PE#%x\n",
 497                         __func__, rc, pe->phb->global_number, pe->addr);
 498                 return (void *)pe;
 499         }
 500
 501         return NULL;
 502 }
 503
 504 static int eeh_clear_pe_frozen_state(struct eeh_pe *pe,
 505                                      bool clear_sw_state)
 506 {
 507         void *rc;
 508
 509         rc = eeh_pe_traverse(pe, __eeh_clear_pe_frozen_state, &clear_sw_state);
 510         if (!rc)
 511                 eeh_pe_state_clear(pe, EEH_PE_ISOLATED);
 512
 513         return rc ? -EIO : 0;
 514 }
 515
 516 int eeh_pe_reset_and_recover(struct eeh_pe *pe)
 517 {
 518         int result, ret;
 519
 520         /* Bail if the PE is being recovered */
 521         if (pe->state & EEH_PE_RECOVERING)
 522                 return 0;
 523
 524         /* Put the PE into recovery mode */
 525         eeh_pe_state_mark(pe, EEH_PE_RECOVERING);
 526
 527         /* Save states */
 528         eeh_pe_dev_traverse(pe, eeh_dev_save_state, NULL);
 529
 530         /* Issue reset */
 531         ret = eeh_reset_pe(pe);
 532         if (ret) {
 533                 eeh_pe_state_clear(pe, EEH_PE_RECOVERING);
 534                 return ret;
 535         }
 536
 537         /* Unfreeze the PE */
 538         ret = eeh_clear_pe_frozen_state(pe, true);
 539         if (ret) {
 540                 eeh_pe_state_clear(pe, EEH_PE_RECOVERING);
 541                 return ret;
 542         }
 543
 544         /* Notify completion of reset */
 545         eeh_pe_dev_traverse(pe, eeh_report_reset, &result);
 546
 547         /* Restore device state */
 548         eeh_pe_dev_traverse(pe, eeh_dev_restore_state, NULL);
 549
 550         /* Resume */
 551         eeh_pe_dev_traverse(pe, eeh_report_resume, NULL);
 552
 553         /* Clear recovery mode */
 554         eeh_pe_state_clear(pe, EEH_PE_RECOVERING);
 555
 556         return 0;
 557 }
 558
 559 /**
 560  * eeh_reset_device - Perform actual reset of a pci slot
 561  * @pe: EEH PE
 562  * @bus: PCI bus corresponding to the isolcated slot
 563  *
 564  * This routine must be called to do reset on the indicated PE.
 565  * During the reset, udev might be invoked because those affected
 566  * PCI devices will be removed and then added.
 567  */
 568 static int eeh_reset_device(struct eeh_pe *pe, struct pci_bus *bus)
 569 {
 570         struct pci_bus *frozen_bus = eeh_pe_bus_get(pe);
 571         struct timeval tstamp;
 572         int cnt, rc, removed = 0;
 573
 574         /* pcibios will clear the counter; save the value */
 575         cnt = pe->freeze_count;
 576         tstamp = pe->tstamp;
 577
 578         /*
 579          * We don't remove the corresponding PE instances because
 580          * we need the information afterwords. The attached EEH
 581          * devices are expected to be attached soon when calling
 582          * into pcibios_add_pci_devices().
 583          */
 584         eeh_pe_state_mark(pe, EEH_PE_KEEP);
 585         if (bus) {
 586                 eeh_pe_state_clear(pe, EEH_PE_PRI_BUS);
 587                 pci_lock_rescan_remove();
 588                 pcibios_remove_pci_devices(bus);
 589                 pci_unlock_rescan_remove();
 590         } else if (frozen_bus) {
 591                 eeh_pe_dev_traverse(pe, eeh_rmv_device, &removed);
 592         }
 593
 594         /*
 595          * Reset the pci controller. (Asserts RST#; resets config space).
 596          * Reconfigure bridges and devices. Don't try to bring the system
 597          * up if the reset failed for some reason.
 598          *
 599          * During the reset, it's very dangerous to have uncontrolled PCI
 600          * config accesses. So we prefer to block them. However, controlled
 601          * PCI config accesses initiated from EEH itself are allowed.
 602          */
 603         rc = eeh_reset_pe(pe);
 604         if (rc)
 605                 return rc;
 606
 607         pci_lock_rescan_remove();
 608
 609         /* Restore PE */
 610         eeh_ops->configure_bridge(pe);
 611         eeh_pe_restore_bars(pe);
 612
 613         /* Clear frozen state */
 614         rc = eeh_clear_pe_frozen_state(pe, false);
 615         if (rc)
 616                 return rc;
 617
 618         /* Give the system 5 seconds to finish running the user-space
 619          * hotplug shutdown scripts, e.g. ifdown for ethernet.  Yes,
 620          * this is a hack, but if we don't do this, and try to bring
 621          * the device up before the scripts have taken it down,
 622          * potentially weird things happen.
 623          */
 624         if (bus) {
 625                 pr_info("EEH: Sleep 5s ahead of complete hotplug\n");
 626                 ssleep(5);
 627
 628                 /*
 629                  * The EEH device is still connected with its parent
 630                  * PE. We should disconnect it so the binding can be
 631                  * rebuilt when adding PCI devices.
 632                  */
 633                 eeh_pe_traverse(pe, eeh_pe_detach_dev, NULL);
 634                 pcibios_add_pci_devices(bus);
 635         } else if (frozen_bus && removed) {
 636                 pr_info("EEH: Sleep 5s ahead of partial hotplug\n");
 637                 ssleep(5);
 638
 639                 eeh_pe_traverse(pe, eeh_pe_detach_dev, NULL);
 640                 pcibios_add_pci_devices(frozen_bus);
 641         }
 642         eeh_pe_state_clear(pe, EEH_PE_KEEP);
 643
 644         pe->tstamp = tstamp;
 645         pe->freeze_count = cnt;
 646
 647         pci_unlock_rescan_remove();
 648         return 0;
 649 }
 650
 651 /* The longest amount of time to wait for a pci device
 652  * to come back on line, in seconds.
 653  */
 654 #define MAX_WAIT_FOR_RECOVERY 300
 655
 656 static void eeh_handle_normal_event(struct eeh_pe *pe)
 657 {
 658         struct pci_bus *frozen_bus;
 659         int rc = 0;
 660         enum pci_ers_result result = PCI_ERS_RESULT_NONE;
 661
 662         frozen_bus = eeh_pe_bus_get(pe);
 663         if (!frozen_bus) {
 664                 pr_err("%s: Cannot find PCI bus for PHB#%d-PE#%x\n",
 665                         __func__, pe->phb->global_number, pe->addr);
 666                 return;
 667         }
 668
 669         eeh_pe_update_time_stamp(pe);
 670         pe->freeze_count++;
 671         if (pe->freeze_count > eeh_max_freezes)
 672                 goto excess_failures;
 673         pr_warn("EEH: This PCI device has failed %d times in the last hour\n",
 674                 pe->freeze_count);
 675
 676         /* Walk the various device drivers attached to this slot through
 677          * a reset sequence, giving each an opportunity to do what it needs
 678          * to accomplish the reset.  Each child gets a report of the
 679          * status ... if any child can't handle the reset, then the entire
 680          * slot is dlpar removed and added.
 681          *
 682          * When the PHB is fenced, we have to issue a reset to recover from
 683          * the error. Override the result if necessary to have partially
 684          * hotplug for this case.
 685          */
 686         pr_info("EEH: Notify device drivers to shutdown\n");
 687         eeh_pe_dev_traverse(pe, eeh_report_error, &result);
 688         if ((pe->type & EEH_PE_PHB) &&
 689             result != PCI_ERS_RESULT_NONE &&
 690             result != PCI_ERS_RESULT_NEED_RESET)
 691                 result = PCI_ERS_RESULT_NEED_RESET;
 692
 693         /* Get the current PCI slot state. This can take a long time,
 694          * sometimes over 300 seconds for certain systems.
 695          */
 696         rc = eeh_ops->wait_state(pe, MAX_WAIT_FOR_RECOVERY*1000);
 697         if (rc < 0 || rc == EEH_STATE_NOT_SUPPORT) {
 698                 pr_warn("EEH: Permanent failure\n");
 699                 goto hard_fail;
 700         }
 701
 702         /* Since rtas may enable MMIO when posting the error log,
 703          * don't post the error log until after all dev drivers
 704          * have been informed.
 705          */
 706         pr_info("EEH: Collect temporary log\n");
 707         eeh_slot_error_detail(pe, EEH_LOG_TEMP);
 708
 709         /* If all device drivers were EEH-unaware, then shut
 710          * down all of the device drivers, and hope they
 711          * go down willingly, without panicing the system.
 712          */
 713         if (result == PCI_ERS_RESULT_NONE) {
 714                 pr_info("EEH: Reset with hotplug activity\n");
 715                 rc = eeh_reset_device(pe, frozen_bus);
 716                 if (rc) {
 717                         pr_warn("%s: Unable to reset, err=%d\n",
 718                                 __func__, rc);
 719                         goto hard_fail;
 720                 }
 721         }
 722
 723         /* If all devices reported they can proceed, then re-enable MMIO */
 724         if (result == PCI_ERS_RESULT_CAN_RECOVER) {
 725                 pr_info("EEH: Enable I/O for affected devices\n");
 726                 rc = eeh_pci_enable(pe, EEH_OPT_THAW_MMIO);
 727
 728                 if (rc < 0)
 729                         goto hard_fail;
 730                 if (rc) {
 731                         result = PCI_ERS_RESULT_NEED_RESET;
 732                 } else {
 733                         pr_info("EEH: Notify device drivers to resume I/O\n");
 734                         eeh_pe_dev_traverse(pe, eeh_report_mmio_enabled, &result);
 735                 }
 736         }
 737
 738         /* If all devices reported they can proceed, then re-enable DMA */
 739         if (result == PCI_ERS_RESULT_CAN_RECOVER) {
 740                 pr_info("EEH: Enabled DMA for affected devices\n");
 741                 rc = eeh_pci_enable(pe, EEH_OPT_THAW_DMA);
 742
 743                 if (rc < 0)
 744                         goto hard_fail;
 745                 if (rc) {
 746                         result = PCI_ERS_RESULT_NEED_RESET;
 747                 } else {
 748                         /*
 749                          * We didn't do PE reset for the case. The PE
 750                          * is still in frozen state. Clear it before
 751                          * resuming the PE.
 752                          */
 753                         eeh_pe_state_clear(pe, EEH_PE_ISOLATED);
 754                         result = PCI_ERS_RESULT_RECOVERED;
 755                 }
 756         }
 757
 758         /* If any device has a hard failure, then shut off everything. */
 759         if (result == PCI_ERS_RESULT_DISCONNECT) {
 760                 pr_warn("EEH: Device driver gave up\n");
 761                 goto hard_fail;
 762         }
 763
 764         /* If any device called out for a reset, then reset the slot */
 765         if (result == PCI_ERS_RESULT_NEED_RESET) {
 766                 pr_info("EEH: Reset without hotplug activity\n");
 767                 rc = eeh_reset_device(pe, NULL);
 768                 if (rc) {
 769                         pr_warn("%s: Cannot reset, err=%d\n",
 770                                 __func__, rc);
 771                         goto hard_fail;
 772                 }
 773
 774                 pr_info("EEH: Notify device drivers "
 775                         "the completion of reset\n");
 776                 result = PCI_ERS_RESULT_NONE;
 777                 eeh_pe_dev_traverse(pe, eeh_report_reset, &result);
 778         }
 779
 780         /* All devices should claim they have recovered by now. */
 781         if ((result != PCI_ERS_RESULT_RECOVERED) &&
 782             (result != PCI_ERS_RESULT_NONE)) {
 783                 pr_warn("EEH: Not recovered\n");
 784                 goto hard_fail;
 785         }
 786
 787         /* Tell all device drivers that they can resume operations */
 788         pr_info("EEH: Notify device driver to resume\n");
 789         eeh_pe_dev_traverse(pe, eeh_report_resume, NULL);
 790
 791         return;
 792
 793 excess_failures:
 794         /*
 795          * About 90% of all real-life EEH failures in the field
 796          * are due to poorly seated PCI cards. Only 10% or so are
 797          * due to actual, failed cards.
 798          */
 799         pr_err("EEH: PHB#%d-PE#%x has failed %d times in the\n"
 800                "last hour and has been permanently disabled.\n"
 801                "Please try reseating or replacing it.\n",
 802                 pe->phb->global_number, pe->addr,
 803                 pe->freeze_count);
 804         goto perm_error;
 805
 806 hard_fail:
 807         pr_err("EEH: Unable to recover from failure from PHB#%d-PE#%x.\n"
 808                "Please try reseating or replacing it\n",
 809                 pe->phb->global_number, pe->addr);
 810
 811 perm_error:
 812         eeh_slot_error_detail(pe, EEH_LOG_PERM);
 813
 814         /* Notify all devices that they're about to go down. */
 815         eeh_pe_dev_traverse(pe, eeh_report_failure, NULL);
 816
 817         /* Mark the PE to be removed permanently */
 818         eeh_pe_state_mark(pe, EEH_PE_REMOVED);
 819
 820         /*
 821          * Shut down the device drivers for good. We mark
 822          * all removed devices correctly to avoid access
 823          * the their PCI config any more.
 824          */
 825         if (frozen_bus) {
 826                 eeh_pe_state_clear(pe, EEH_PE_PRI_BUS);
 827                 eeh_pe_dev_mode_mark(pe, EEH_DEV_REMOVED);
 828
 829                 pci_lock_rescan_remove();
 830                 pcibios_remove_pci_devices(frozen_bus);
 831                 pci_unlock_rescan_remove();
 832         }
 833 }
 834
 835 static void eeh_handle_special_event(void)
 836 {
 837         struct eeh_pe *pe, *phb_pe;
 838         struct pci_bus *bus;
 839         struct pci_controller *hose;
 840         unsigned long flags;
 841         int rc;
 842
 843
 844         do {
 845                 rc = eeh_ops->next_error(&pe);
 846
 847                 switch (rc) {
 848                 case EEH_NEXT_ERR_DEAD_IOC:
 849                         /* Mark all PHBs in dead state */
 850                         eeh_serialize_lock(&flags);
 851
 852                         /* Purge all events */
 853                         eeh_remove_event(NULL, true);
 854
 855                         list_for_each_entry(hose, &hose_list, list_node) {
 856                                 phb_pe = eeh_phb_pe_get(hose);
 857                                 if (!phb_pe) continue;
 858
 859                                 eeh_pe_state_mark(phb_pe, EEH_PE_ISOLATED);
 860                         }
 861
 862                         eeh_serialize_unlock(flags);
 863
 864                         break;
 865                 case EEH_NEXT_ERR_FROZEN_PE:
 866                 case EEH_NEXT_ERR_FENCED_PHB:
 867                 case EEH_NEXT_ERR_DEAD_PHB:
 868                         /* Mark the PE in fenced state */
 869                         eeh_serialize_lock(&flags);
 870
 871                         /* Purge all events of the PHB */
 872                         eeh_remove_event(pe, true);
 873
 874                         if (rc == EEH_NEXT_ERR_DEAD_PHB)
 875                                 eeh_pe_state_mark(pe, EEH_PE_ISOLATED);
 876                         else
 877                                 eeh_pe_state_mark(pe,
 878                                         EEH_PE_ISOLATED | EEH_PE_RECOVERING);
 879
 880                         eeh_serialize_unlock(flags);
 881
 882                         break;
 883                 case EEH_NEXT_ERR_NONE:
 884                         return;
 885                 default:
 886                         pr_warn("%s: Invalid value %d from next_error()\n",
 887                                 __func__, rc);
 888                         return;
 889                 }
 890
 891                 /*
 892                  * For fenced PHB and frozen PE, it's handled as normal
 893                  * event. We have to remove the affected PHBs for dead
 894                  * PHB and IOC
 895                  */
 896                 if (rc == EEH_NEXT_ERR_FROZEN_PE ||
 897                     rc == EEH_NEXT_ERR_FENCED_PHB) {
 898                         eeh_handle_normal_event(pe);
 899                         eeh_pe_state_clear(pe, EEH_PE_RECOVERING);
 900                 } else {
 901                         pci_lock_rescan_remove();
 902                         list_for_each_entry(hose, &hose_list, list_node) {
 903                                 phb_pe = eeh_phb_pe_get(hose);
 904                                 if (!phb_pe ||
 905                                     !(phb_pe->state & EEH_PE_ISOLATED) ||
 906                                     (phb_pe->state & EEH_PE_RECOVERING))
 907                                         continue;
 908
 909                                 /* Notify all devices to be down */
 910                                 eeh_pe_state_clear(pe, EEH_PE_PRI_BUS);
 911                                 bus = eeh_pe_bus_get(phb_pe);
 912                                 if (!bus) {
 913                                         pr_err("%s: Cannot find PCI bus for "
 914                                                "PHB#%d-PE#%x\n",
 915                                                __func__,
 916                                                pe->phb->global_number,
 917                                                pe->addr);
 918                                         break;
 919                                 }
 920                                 eeh_pe_dev_traverse(pe,
 921                                         eeh_report_failure, NULL);
 922                                 pcibios_remove_pci_devices(bus);
 923                         }
 924                         pci_unlock_rescan_remove();
 925                 }
 926
 927                 /*
 928                  * If we have detected dead IOC, we needn't proceed
 929                  * any more since all PHBs would have been removed
 930                  */
 931                 if (rc == EEH_NEXT_ERR_DEAD_IOC)
 932                         break;
 933         } while (rc != EEH_NEXT_ERR_NONE);
 934 }
 935
 936 /**
 937  * eeh_handle_event - Reset a PCI device after hard lockup.
 938  * @pe: EEH PE
 939  *
 940  * While PHB detects address or data parity errors on particular PCI
 941  * slot, the associated PE will be frozen. Besides, DMA's occurring
 942  * to wild addresses (which usually happen due to bugs in device
 943  * drivers or in PCI adapter firmware) can cause EEH error. #SERR,
 944  * #PERR or other misc PCI-related errors also can trigger EEH errors.
 945  *
 946  * Recovery process consists of unplugging the device driver (which
 947  * generated hotplug events to userspace), then issuing a PCI #RST to
 948  * the device, then reconfiguring the PCI config space for all bridges
 949  * & devices under this slot, and then finally restarting the device
 950  * drivers (which cause a second set of hotplug events to go out to
 951  * userspace).
 952  */
 953 void eeh_handle_event(struct eeh_pe *pe)
 954 {
 955         if (pe)
 956                 eeh_handle_normal_event(pe);
 957         else
 958                 eeh_handle_special_event();
 959 }