LXR linux/arch/powerpc/platforms/pseries/eeh

   1/*
   2 * eeh_event.c
   3 *
   4 * This program is free software; you can redistribute it and/or modify
   5 * it under the terms of the GNU General Public License as published by
   6 * the Free Software Foundation; either version 2 of the License, or
   7 * (at your option) any later version.
   8 *
   9 * This program is distributed in the hope that it will be useful,
  10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 * GNU General Public License for more details.
  13 *
  14 * You should have received a copy of the GNU General Public License
  15 * along with this program; if not, write to the Free Software
  16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  17 *
  18 * Copyright (c) 2005 Linas Vepstas <linas@linas.org>
  19 */
  20
  21#include <linux/delay.h>
  22#include <linux/list.h>
  23#include <linux/mutex.h>
  24#include <linux/pci.h>
  25#include <linux/workqueue.h>
  26#include <asm/eeh_event.h>
  27#include <asm/ppc-pci.h>
  28
  29/** Overview:
  30 *  EEH error states may be detected within exception handlers;
  31 *  however, the recovery processing needs to occur asynchronously
  32 *  in a normal kernel context and not an interrupt context.
  33 *  This pair of routines creates an event and queues it onto a
  34 *  work-queue, where a worker thread can drive recovery.
  35 */
  36
  37/* EEH event workqueue setup. */
  38static DEFINE_SPINLOCK(eeh_eventlist_lock);
  39LIST_HEAD(eeh_eventlist);
  40static void eeh_thread_launcher(struct work_struct *);
  41DECLARE_WORK(eeh_event_wq, eeh_thread_launcher);
  42
  43/* Serialize reset sequences for a given pci device */
  44DEFINE_MUTEX(eeh_event_mutex);
  45
  46/**
  47 * eeh_event_handler - dispatch EEH events.
  48 * @dummy - unused
  49 *
  50 * The detection of a frozen slot can occur inside an interrupt,
  51 * where it can be hard to do anything about it.  The goal of this
  52 * routine is to pull these detection events out of the context
  53 * of the interrupt handler, and re-dispatch them for processing
  54 * at a later time in a normal context.
  55 */
  56static int eeh_event_handler(void * dummy)
  57{
  58        unsigned long flags;
  59        struct eeh_event        *event;
  60        struct pci_dn *pdn;
  61
  62        daemonize ("eehd");
  63        set_current_state(TASK_INTERRUPTIBLE);
  64
  65        spin_lock_irqsave(&eeh_eventlist_lock, flags);
  66        event = NULL;
  67
  68        /* Unqueue the event, get ready to process. */
  69        if (!list_empty(&eeh_eventlist)) {
  70                event = list_entry(eeh_eventlist.next, struct eeh_event, list);
  71                list_del(&event->list);
  72        }
  73        spin_unlock_irqrestore(&eeh_eventlist_lock, flags);
  74
  75        if (event == NULL)
  76                return 0;
  77
  78        /* Serialize processing of EEH events */
  79        mutex_lock(&eeh_event_mutex);
  80        eeh_mark_slot(event->dn, EEH_MODE_RECOVERING);
  81
  82        printk(KERN_INFO "EEH: Detected PCI bus error on device %s\n",
  83               pci_name(event->dev));
  84
  85        pdn = handle_eeh_events(event);
  86
  87        eeh_clear_slot(event->dn, EEH_MODE_RECOVERING);
  88        pci_dev_put(event->dev);
  89        kfree(event);
  90        mutex_unlock(&eeh_event_mutex);
  91
  92        /* If there are no new errors after an hour, clear the counter. */
  93        if (pdn && pdn->eeh_freeze_count>0) {
  94                msleep_interruptible (3600*1000);
  95                if (pdn->eeh_freeze_count>0)
  96                        pdn->eeh_freeze_count--;
  97        }
  98
  99        return 0;
 100}
 101
 102/**
 103 * eeh_thread_launcher
 104 * @dummy - unused
 105 */
 106static void eeh_thread_launcher(struct work_struct *dummy)
 107{
 108        if (kernel_thread(eeh_event_handler, NULL, CLONE_KERNEL) < 0)
 109                printk(KERN_ERR "Failed to start EEH daemon\n");
 110}
 111
 112/**
 113 * eeh_send_failure_event - generate a PCI error event
 114 * @dev pci device
 115 *
 116 * This routine can be called within an interrupt context;
 117 * the actual event will be delivered in a normal context
 118 * (from a workqueue).
 119 */
 120int eeh_send_failure_event (struct device_node *dn,
 121                            struct pci_dev *dev)
 122{
 123        unsigned long flags;
 124        struct eeh_event *event;
 125        const char *location;
 126
 127        if (!mem_init_done) {
 128                printk(KERN_ERR "EEH: event during early boot not handled\n");
 129                location = of_get_property(dn, "ibm,loc-code", NULL);
 130                printk(KERN_ERR "EEH: device node = %s\n", dn->full_name);
 131                printk(KERN_ERR "EEH: PCI location = %s\n", location);
 132                return 1;
 133        }
 134        event = kmalloc(sizeof(*event), GFP_ATOMIC);
 135        if (event == NULL) {
 136                printk (KERN_ERR "EEH: out of memory, event not handled\n");
 137                return 1;
 138        }
 139
 140        if (dev)
 141                pci_dev_get(dev);
 142
 143        event->dn = dn;
 144        event->dev = dev;
 145
 146        /* We may or may not be called in an interrupt context */
 147        spin_lock_irqsave(&eeh_eventlist_lock, flags);
 148        list_add(&event->list, &eeh_eventlist);
 149        spin_unlock_irqrestore(&eeh_eventlist_lock, flags);
 150
 151        schedule_work(&eeh_event_wq);
 152
 153        return 0;
 154}
 155
 156/********************** END OF FILE ******************************/
 157