Adding support for MOXA ART SoC. Testing port of linux-2.6.32.60-moxart.

[linux-3.6.7-moxart.git] / arch / powerpc / platforms / pseries / eeh_driver.c

/*
 * PCI Error Recovery Driver for RPA-compliant PPC64 platform.
 * Copyright IBM Corp. 2004 2005
 * Copyright Linas Vepstas <linas@linas.org> 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 <linas@austin.ibm.com>
 */
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/irq.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>

/**
 * eeh_pcid_name - Retrieve name of PCI device driver
 * @pdev: PCI device
 *
 * This routine is used to retrieve the name of PCI device driver
 * if that's valid.
 */
static inline const char *eeh_pcid_name(struct pci_dev *pdev)
{
        if (pdev && pdev->dev.driver)
                return pdev->dev.driver->name;
        return "";
}

#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

/**
 * eeh_disable_irq - Disable interrupt for the recovering device
 * @dev: PCI device
 *
 * This routine must be called when reporting temporary or permanent
 * error to the particular PCI device to disable interrupt of that
 * device. If the device has enabled MSI or MSI-X interrupt, we needn't
 * do real work because EEH should freeze DMA transfers for those PCI
 * devices encountering EEH errors, which includes MSI or MSI-X.
 */
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_MODE_IRQ_DISABLED;
        disable_irq_nosync(dev->irq);
}

/**
 * eeh_enable_irq - Enable interrupt for the recovering device
 * @dev: PCI device
 *
 * This routine must be called to enable interrupt while failed
 * device could be resumed.
 */
static void eeh_enable_irq(struct pci_dev *dev)
{
        struct eeh_dev *edev = pci_dev_to_eeh_dev(dev);

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

/**
 * eeh_report_error - Report pci error to each device driver
 * @dev: PCI device
 * @userdata: return value
 * 
 * Report an EEH error to each device driver, collect up and 
 * merge the device driver responses. Cumulative response 
 * passed back in "userdata".
 */
static int eeh_report_error(struct pci_dev *dev, void *userdata)
{
        enum pci_ers_result rc, *res = userdata;
        struct pci_driver *driver = dev->driver;

        dev->error_state = pci_channel_io_frozen;

        if (!driver)
                return 0;

        eeh_disable_irq(dev);

        if (!driver->err_handler ||
            !driver->err_handler->error_detected)
                return 0;

        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;

        return 0;
}

/**
 * eeh_report_mmio_enabled - Tell drivers that MMIO has been enabled
 * @dev: PCI device
 * @userdata: return value
 *
 * Tells each device driver that IO ports, MMIO and config space I/O
 * are now enabled. Collects up and merges the device driver responses.
 * Cumulative response passed back in "userdata".
 */
static int eeh_report_mmio_enabled(struct pci_dev *dev, void *userdata)
{
        enum pci_ers_result rc, *res = userdata;
        struct pci_driver *driver = dev->driver;

        if (!driver ||
            !driver->err_handler ||
            !driver->err_handler->mmio_enabled)
                return 0;

        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;

        return 0;
}

/**
 * eeh_report_reset - Tell device that slot has been reset
 * @dev: PCI device
 * @userdata: return value
 *
 * This routine must be called while EEH tries to reset particular
 * PCI device so that the associated PCI device driver could take
 * some actions, usually to save data the driver needs so that the
 * driver can work again while the device is recovered.
 */
static int eeh_report_reset(struct pci_dev *dev, void *userdata)
{
        enum pci_ers_result rc, *res = userdata;
        struct pci_driver *driver = dev->driver;

        if (!driver)
                return 0;

        dev->error_state = pci_channel_io_normal;

        eeh_enable_irq(dev);

        if (!driver->err_handler ||
            !driver->err_handler->slot_reset)
                return 0;

        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;

        return 0;
}

/**
 * eeh_report_resume - Tell device to resume normal operations
 * @dev: PCI device
 * @userdata: return value
 *
 * This routine must be called to notify the device driver that it
 * could resume so that the device driver can do some initialization
 * to make the recovered device work again.
 */
static int eeh_report_resume(struct pci_dev *dev, void *userdata)
{
        struct pci_driver *driver = dev->driver;

        dev->error_state = pci_channel_io_normal;

        if (!driver)
                return 0;

        eeh_enable_irq(dev);

        if (!driver->err_handler ||
            !driver->err_handler->resume)
                return 0;

        driver->err_handler->resume(dev);

        return 0;
}

/**
 * eeh_report_failure - Tell device driver that device is dead.
 * @dev: PCI device
 * @userdata: return value
 *
 * This informs the device driver that the device is permanently
 * dead, and that no further recovery attempts will be made on it.
 */
static int eeh_report_failure(struct pci_dev *dev, void *userdata)
{
        struct pci_driver *driver = dev->driver;

        dev->error_state = pci_channel_io_perm_failure;

        if (!driver)
                return 0;

        eeh_disable_irq(dev);

        if (!driver->err_handler ||
            !driver->err_handler->error_detected)
                return 0;

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

        return 0;
}

/**
 * eeh_reset_device - Perform actual reset of a pci slot
 * @edev: PE associated EEH device
 * @bus: PCI bus corresponding to the isolcated slot
 *
 * This routine must be called to do reset on the indicated PE.
 * During the reset, udev might be invoked because those affected
 * PCI devices will be removed and then added.
 */
static int eeh_reset_device(struct eeh_dev *edev, struct pci_bus *bus)
{
        struct device_node *dn;
        int cnt, rc;

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

        if (bus)
                pcibios_remove_pci_devices(bus);

        /* 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(edev);
        if (rc)
                return rc;

        /* Walk over all functions on this device. */
        dn = eeh_dev_to_of_node(edev);
        if (!pcibios_find_pci_bus(dn) && of_node_to_eeh_dev(dn->parent))
                dn = dn->parent->child;

        while (dn) {
                struct eeh_dev *pedev = of_node_to_eeh_dev(dn);

                /* On Power4, always true because eeh_pe_config_addr=0 */
                if (edev->pe_config_addr == pedev->pe_config_addr) {
                        eeh_ops->configure_bridge(dn);
                        eeh_restore_bars(pedev);
                }
                dn = dn->sibling;
        }

        /* 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);
        }
        edev->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

/**
 * eeh_handle_event - Reset a PCI device after hard lockup.
 * @event: EEH event
 *
 * While PHB detects address or data parity errors on particular PCI
 * slot, the associated PE will be frozen. Besides, DMA's occurring
 * to wild addresses (which usually happen due to bugs in device
 * drivers or in PCI adapter firmware) can cause EEH error. #SERR,
 * #PERR or other misc PCI-related errors also can trigger EEH errors.
 *
 * Recovery process consists of unplugging the device driver (which
 * generated hotplug events to userspace), then issuing a PCI #RST to
 * the device, then reconfiguring the PCI config space for all bridges
 * & devices under this slot, and then finally restarting the device
 * drivers (which cause a second set of hotplug events to go out to
 * userspace).
 */
struct eeh_dev *handle_eeh_events(struct eeh_event *event)
{
        struct device_node *frozen_dn;
        struct eeh_dev *frozen_edev;
        struct pci_bus *frozen_bus;
        int rc = 0;
        enum pci_ers_result result = PCI_ERS_RESULT_NONE;
        const char *location, *pci_str, *drv_str, *bus_pci_str, *bus_drv_str;

        frozen_dn = eeh_find_device_pe(eeh_dev_to_of_node(event->edev));
        if (!frozen_dn) {
                location = of_get_property(eeh_dev_to_of_node(event->edev), "ibm,loc-code", NULL);
                location = location ? location : "unknown";
                printk(KERN_ERR "EEH: Error: Cannot find partition endpoint "
                                "for location=%s pci addr=%s\n",
                        location, eeh_pci_name(eeh_dev_to_pci_dev(event->edev)));
                return NULL;
        }

        frozen_bus = pcibios_find_pci_bus(frozen_dn);
        location = of_get_property(frozen_dn, "ibm,loc-code", NULL);
        location = location ? location : "unknown";

        /* There are two different styles for coming up with the PE.
         * In the old style, it was the highest EEH-capable device
         * which was always an EADS pci bridge.  In the new style,
         * there might not be any EADS bridges, and even when there are,
         * the firmware marks them as "EEH incapable". So another
         * two-step is needed to find the pci bus..
         */
        if (!frozen_bus)
                frozen_bus = pcibios_find_pci_bus(frozen_dn->parent);

        if (!frozen_bus) {
                printk(KERN_ERR "EEH: Cannot find PCI bus "
                        "for location=%s dn=%s\n",
                        location, frozen_dn->full_name);
                return NULL;
        }

        frozen_edev = of_node_to_eeh_dev(frozen_dn);
        frozen_edev->freeze_count++;
        pci_str = eeh_pci_name(eeh_dev_to_pci_dev(event->edev));
        drv_str = eeh_pcid_name(eeh_dev_to_pci_dev(event->edev));

        if (frozen_edev->freeze_count > EEH_MAX_ALLOWED_FREEZES)
                goto excess_failures;

        printk(KERN_WARNING
           "EEH: This PCI device has failed %d times in the last hour:\n",
                frozen_edev->freeze_count);

        if (frozen_edev->pdev) {
                bus_pci_str = pci_name(frozen_edev->pdev);
                bus_drv_str = eeh_pcid_name(frozen_edev->pdev);
                printk(KERN_WARNING
                        "EEH: Bus location=%s driver=%s pci addr=%s\n",
                        location, bus_drv_str, bus_pci_str);
        }

        printk(KERN_WARNING
                "EEH: Device location=%s driver=%s pci addr=%s\n",
                location, drv_str, pci_str);

        /* 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.
         */
        pci_walk_bus(frozen_bus, 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(eeh_dev_to_of_node(frozen_edev), 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(frozen_edev, 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(frozen_edev, 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(frozen_edev, EEH_OPT_THAW_MMIO);

                if (rc < 0)
                        goto hard_fail;
                if (rc) {
                        result = PCI_ERS_RESULT_NEED_RESET;
                } else {
                        result = PCI_ERS_RESULT_NONE;
                        pci_walk_bus(frozen_bus, 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(frozen_edev, 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(frozen_edev, NULL);
                if (rc) {
                        printk(KERN_WARNING "EEH: Cannot reset, rc=%d\n", rc);
                        goto hard_fail;
                }
                result = PCI_ERS_RESULT_NONE;
                pci_walk_bus(frozen_bus, 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 */
        pci_walk_bus(frozen_bus, eeh_report_resume, NULL);

        return frozen_edev;
        
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.
         */
        printk(KERN_ERR
           "EEH: PCI device at location=%s driver=%s pci addr=%s\n"
                "has failed %d times in the last hour "
                "and has been permanently disabled.\n"
                "Please try reseating this device or replacing it.\n",
                location, drv_str, pci_str, frozen_edev->freeze_count);
        goto perm_error;

hard_fail:
        printk(KERN_ERR
           "EEH: Unable to recover from failure of PCI device "
           "at location=%s driver=%s pci addr=%s\n"
           "Please try reseating this device or replacing it.\n",
                location, drv_str, pci_str);

perm_error:
        eeh_slot_error_detail(frozen_edev, EEH_LOG_PERM);

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

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

        return NULL;
}