eeh_driver.c

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/*
 * PCI Error Recovery Driver for RPA-compliant PPC64 platform.
 * Copyright IBM Corp. 2004 2005
 * Copyright Linas Vepstas <[email protected]> 2004, 2005
 *
 * All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or (at
 * your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
 * NON INFRINGEMENT.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * Send comments and feedback to Linas Vepstas <[email protected]>
 */
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <asm/eeh.h>
#include <asm/eeh_event.h>
#include <asm/ppc-pci.h>
#include <asm/pci-bridge.h>
#include <asm/prom.h>
#include <asm/rtas.h>

static inline const char *eeh_pcid_name(struct pci_dev *pdev)
{
    if (pdev && pdev->dev.driver)
        return pdev->dev.driver->name;
    return "";
}

static inline struct pci_driver *eeh_pcid_get(struct pci_dev *pdev)
{
    if (!pdev || !pdev->driver)
        return NULL;

    if (!try_module_get(pdev->driver->driver.owner))
        return NULL;

    return pdev->driver;
}

static inline void eeh_pcid_put(struct pci_dev *pdev)
{
    if (!pdev || !pdev->driver)
        return;

    module_put(pdev->driver->driver.owner);
}

#if 0
static void print_device_node_tree(struct pci_dn *pdn, int dent)
{
    int i;
    struct device_node *pc;

    if (!pdn)
        return;
    for (i = 0; i < dent; i++)
        printk(" ");
    printk("dn=%s mode=%x \tcfg_addr=%x pe_addr=%x \tfull=%s\n",
        pdn->node->name, pdn->eeh_mode, pdn->eeh_config_addr,
        pdn->eeh_pe_config_addr, pdn->node->full_name);
    dent += 3;
    pc = pdn->node->child;
    while (pc) {
        print_device_node_tree(PCI_DN(pc), dent);
        pc = pc->sibling;
    }
}
#endif

static void eeh_disable_irq(struct pci_dev *dev)
{
    struct eeh_dev *edev = pci_dev_to_eeh_dev(dev);

    /* Don't disable MSI and MSI-X interrupts. They are
     * effectively disabled by the DMA Stopped state
     * when an EEH error occurs.
     */
    if (dev->msi_enabled || dev->msix_enabled)
        return;

    if (!irq_has_action(dev->irq))
        return;

    edev->mode |= EEH_DEV_IRQ_DISABLED;
    disable_irq_nosync(dev->irq);
}

static void eeh_enable_irq(struct pci_dev *dev)
{
    struct eeh_dev *edev = pci_dev_to_eeh_dev(dev);

    if ((edev->mode) & EEH_DEV_IRQ_DISABLED) {
        edev->mode &= ~EEH_DEV_IRQ_DISABLED;
        enable_irq(dev->irq);
    }
}

static void *eeh_report_error(void *data, void *userdata)
{
    struct eeh_dev *edev = (struct eeh_dev *)data;
    struct pci_dev *dev = eeh_dev_to_pci_dev(edev);
    enum pci_ers_result rc, *res = userdata;
    struct pci_driver *driver;

    /* We might not have the associated PCI device,
     * then we should continue for next one.
     */
    if (!dev) return NULL;
    dev->error_state = pci_channel_io_frozen;

    driver = eeh_pcid_get(dev);
    if (!driver) return NULL;

    eeh_disable_irq(dev);

    if (!driver->err_handler ||
        !driver->err_handler->error_detected) {
        eeh_pcid_put(dev);
        return NULL;
    }

    rc = driver->err_handler->error_detected(dev, pci_channel_io_frozen);

    /* A driver that needs a reset trumps all others */
    if (rc == PCI_ERS_RESULT_NEED_RESET) *res = rc;
    if (*res == PCI_ERS_RESULT_NONE) *res = rc;

    eeh_pcid_put(dev);
    return NULL;
}

static void *eeh_report_mmio_enabled(void *data, void *userdata)
{
    struct eeh_dev *edev = (struct eeh_dev *)data;
    struct pci_dev *dev = eeh_dev_to_pci_dev(edev);
    enum pci_ers_result rc, *res = userdata;
    struct pci_driver *driver;

    driver = eeh_pcid_get(dev);
    if (!driver) return NULL;

    if (!driver->err_handler ||
        !driver->err_handler->mmio_enabled) {
        eeh_pcid_put(dev);
        return NULL;
    }

    rc = driver->err_handler->mmio_enabled(dev);

    /* A driver that needs a reset trumps all others */
    if (rc == PCI_ERS_RESULT_NEED_RESET) *res = rc;
    if (*res == PCI_ERS_RESULT_NONE) *res = rc;

    eeh_pcid_put(dev);
    return NULL;
}

static void *eeh_report_reset(void *data, void *userdata)
{
    struct eeh_dev *edev = (struct eeh_dev *)data;
    struct pci_dev *dev = eeh_dev_to_pci_dev(edev);
    enum pci_ers_result rc, *res = userdata;
    struct pci_driver *driver;

    if (!dev) return NULL;
    dev->error_state = pci_channel_io_normal;

    driver = eeh_pcid_get(dev);
    if (!driver) return NULL;

    eeh_enable_irq(dev);

    if (!driver->err_handler ||
        !driver->err_handler->slot_reset) {
        eeh_pcid_put(dev);
        return NULL;
    }

    rc = driver->err_handler->slot_reset(dev);
    if ((*res == PCI_ERS_RESULT_NONE) ||
        (*res == PCI_ERS_RESULT_RECOVERED)) *res = rc;
    if (*res == PCI_ERS_RESULT_DISCONNECT &&
         rc == PCI_ERS_RESULT_NEED_RESET) *res = rc;

    eeh_pcid_put(dev);
    return NULL;
}

static void *eeh_report_resume(void *data, void *userdata)
{
    struct eeh_dev *edev = (struct eeh_dev *)data;
    struct pci_dev *dev = eeh_dev_to_pci_dev(edev);
    struct pci_driver *driver;

    if (!dev) return NULL;
    dev->error_state = pci_channel_io_normal;

    driver = eeh_pcid_get(dev);
    if (!driver) return NULL;

    eeh_enable_irq(dev);

    if (!driver->err_handler ||
        !driver->err_handler->resume) {
        eeh_pcid_put(dev);
        return NULL;
    }

    driver->err_handler->resume(dev);

    eeh_pcid_put(dev);
    return NULL;
}

static void *eeh_report_failure(void *data, void *userdata)
{
    struct eeh_dev *edev = (struct eeh_dev *)data;
    struct pci_dev *dev = eeh_dev_to_pci_dev(edev);
    struct pci_driver *driver;

    if (!dev) return NULL;
    dev->error_state = pci_channel_io_perm_failure;

    driver = eeh_pcid_get(dev);
    if (!driver) return NULL;

    eeh_disable_irq(dev);

    if (!driver->err_handler ||
        !driver->err_handler->error_detected) {
        eeh_pcid_put(dev);
        return NULL;
    }

    driver->err_handler->error_detected(dev, pci_channel_io_perm_failure);

    eeh_pcid_put(dev);
    return NULL;
}

static int eeh_reset_device(struct eeh_pe *pe, struct pci_bus *bus)
{
    int cnt, rc;

    /* pcibios will clear the counter; save the value */
    cnt = pe->freeze_count;

    /*
     * We don't remove the corresponding PE instances because
     * we need the information afterwords. The attached EEH
     * devices are expected to be attached soon when calling
     * into pcibios_add_pci_devices().
     */
    if (bus)
        __pcibios_remove_pci_devices(bus, 0);

    /* Reset the pci controller. (Asserts RST#; resets config space).
     * Reconfigure bridges and devices. Don't try to bring the system
     * up if the reset failed for some reason.
     */
    rc = eeh_reset_pe(pe);
    if (rc)
        return rc;

    /* Restore PE */
    eeh_ops->configure_bridge(pe);
    eeh_pe_restore_bars(pe);

    /* Give the system 5 seconds to finish running the user-space
     * hotplug shutdown scripts, e.g. ifdown for ethernet.  Yes, 
     * this is a hack, but if we don't do this, and try to bring 
     * the device up before the scripts have taken it down, 
     * potentially weird things happen.
     */
    if (bus) {
        ssleep(5);
        pcibios_add_pci_devices(bus);
    }
    pe->freeze_count = cnt;

    return 0;
}

/* The longest amount of time to wait for a pci device
 * to come back on line, in seconds.
 */
#define MAX_WAIT_FOR_RECOVERY 150

void eeh_handle_event(struct eeh_pe *pe)
{
    struct pci_bus *frozen_bus;
    int rc = 0;
    enum pci_ers_result result = PCI_ERS_RESULT_NONE;

    frozen_bus = eeh_pe_bus_get(pe);
    if (!frozen_bus) {
        pr_err("%s: Cannot find PCI bus for PHB#%d-PE#%x\n",
            __func__, pe->phb->global_number, pe->addr);
        return;
    }

    pe->freeze_count++;
    if (pe->freeze_count > EEH_MAX_ALLOWED_FREEZES)
        goto excess_failures;
    pr_warning("EEH: This PCI device has failed %d times in the last hour\n",
        pe->freeze_count);

    /* Walk the various device drivers attached to this slot through
     * a reset sequence, giving each an opportunity to do what it needs
     * to accomplish the reset.  Each child gets a report of the
     * status ... if any child can't handle the reset, then the entire
     * slot is dlpar removed and added.
     */
    eeh_pe_dev_traverse(pe, eeh_report_error, &result);

    /* Get the current PCI slot state. This can take a long time,
     * sometimes over 3 seconds for certain systems.
     */
    rc = eeh_ops->wait_state(pe, MAX_WAIT_FOR_RECOVERY*1000);
    if (rc < 0 || rc == EEH_STATE_NOT_SUPPORT) {
        printk(KERN_WARNING "EEH: Permanent failure\n");
        goto hard_fail;
    }

    /* Since rtas may enable MMIO when posting the error log,
     * don't post the error log until after all dev drivers
     * have been informed.
     */
    eeh_slot_error_detail(pe, EEH_LOG_TEMP);

    /* If all device drivers were EEH-unaware, then shut
     * down all of the device drivers, and hope they
     * go down willingly, without panicing the system.
     */
    if (result == PCI_ERS_RESULT_NONE) {
        rc = eeh_reset_device(pe, frozen_bus);
        if (rc) {
            printk(KERN_WARNING "EEH: Unable to reset, rc=%d\n", rc);
            goto hard_fail;
        }
    }

    /* If all devices reported they can proceed, then re-enable MMIO */
    if (result == PCI_ERS_RESULT_CAN_RECOVER) {
        rc = eeh_pci_enable(pe, EEH_OPT_THAW_MMIO);

        if (rc < 0)
            goto hard_fail;
        if (rc) {
            result = PCI_ERS_RESULT_NEED_RESET;
        } else {
            result = PCI_ERS_RESULT_NONE;
            eeh_pe_dev_traverse(pe, eeh_report_mmio_enabled, &result);
        }
    }

    /* If all devices reported they can proceed, then re-enable DMA */
    if (result == PCI_ERS_RESULT_CAN_RECOVER) {
        rc = eeh_pci_enable(pe, EEH_OPT_THAW_DMA);

        if (rc < 0)
            goto hard_fail;
        if (rc)
            result = PCI_ERS_RESULT_NEED_RESET;
        else
            result = PCI_ERS_RESULT_RECOVERED;
    }

    /* If any device has a hard failure, then shut off everything. */
    if (result == PCI_ERS_RESULT_DISCONNECT) {
        printk(KERN_WARNING "EEH: Device driver gave up\n");
        goto hard_fail;
    }

    /* If any device called out for a reset, then reset the slot */
    if (result == PCI_ERS_RESULT_NEED_RESET) {
        rc = eeh_reset_device(pe, NULL);
        if (rc) {
            printk(KERN_WARNING "EEH: Cannot reset, rc=%d\n", rc);
            goto hard_fail;
        }
        result = PCI_ERS_RESULT_NONE;
        eeh_pe_dev_traverse(pe, eeh_report_reset, &result);
    }

    /* All devices should claim they have recovered by now. */
    if ((result != PCI_ERS_RESULT_RECOVERED) &&
        (result != PCI_ERS_RESULT_NONE)) {
        printk(KERN_WARNING "EEH: Not recovered\n");
        goto hard_fail;
    }

    /* Tell all device drivers that they can resume operations */
    eeh_pe_dev_traverse(pe, eeh_report_resume, NULL);

    return;
    
excess_failures:
    /*
     * About 90% of all real-life EEH failures in the field
     * are due to poorly seated PCI cards. Only 10% or so are
     * due to actual, failed cards.
     */
    pr_err("EEH: PHB#%d-PE#%x has failed %d times in the\n"
           "last hour and has been permanently disabled.\n"
           "Please try reseating or replacing it.\n",
        pe->phb->global_number, pe->addr,
        pe->freeze_count);
    goto perm_error;

hard_fail:
    pr_err("EEH: Unable to recover from failure from PHB#%d-PE#%x.\n"
           "Please try reseating or replacing it\n",
        pe->phb->global_number, pe->addr);

perm_error:
    eeh_slot_error_detail(pe, EEH_LOG_PERM);

    /* Notify all devices that they're about to go down. */
    eeh_pe_dev_traverse(pe, eeh_report_failure, NULL);

    /* Shut down the device drivers for good. */
    if (frozen_bus)
        pcibios_remove_pci_devices(frozen_bus);
}