/*
* eeh_event.c
*
* 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. 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Copyright (c) 2005 Linas Vepstas <linas@linas.org>
*/
#include <linux/list.h>
#include <linux/pci.h>
#include <asm/eeh_event.h>
/** Overview:
* EEH error states may be detected within exception handlers;
* however, the recovery processing needs to occur asynchronously
* in a normal kernel context and not an interrupt context.
* This pair of routines creates an event and queues it onto a
* work-queue, where a worker thread can drive recovery.
*/
/* EEH event workqueue setup. */
static spinlock_t eeh_eventlist_lock = SPIN_LOCK_UNLOCKED;
LIST_HEAD(eeh_eventlist);
static void eeh_thread_launcher(void *);
DECLARE_WORK(eeh_event_wq, eeh_thread_launcher, NULL);
/**
* eeh_panic - call panic() for an eeh event that cannot be handled.
* The philosophy of this routine is that it is better to panic and
* halt the OS than it is to risk possible data corruption by
* oblivious device drivers that don't know better.
*
* @dev pci device that had an eeh event
* @reset_state current reset state of the device slot
*/
static void eeh_panic(struct pci_dev *dev, int reset_state)
{
/*
* Since the panic_on_oops sysctl is used to halt the system
* in light of potential corruption, we can use it here.
*/
if (panic_on_oops) {
panic("EEH: MMIO failure (%d) on device:%s\n", reset_state,
pci_name(dev));
}
else {
printk(KERN_INFO "EEH: Ignored MMIO failure (%d) on device:%s\n",
reset_state, pci_name(dev));
}
}
/**
* eeh_event_handler - dispatch EEH events. The detection of a frozen
* slot can occur inside an interrupt, where it can be hard to do
* anything about it. The goal of this routine is to pull these
* detection events out of the context of the interrupt handler, and
* re-dispatch them for processing at a later time in a normal context.
*
* @dummy - unused
*/
static int eeh_event_handler(void * dummy)
{
unsigned long flags;
struct eeh_event *event;
daemonize ("eehd");
while (1) {
set_current_state(TASK_INTERRUPTIBLE);
spin_lock_irqsave(&eeh_eventlist_lock, flags);
event = NULL;
if (!list_empty(&eeh_eventlist)) {
event = list_entry(eeh_eventlist.next, struct eeh_event, list);
list_del(&event->list);
}
spin_unlock_irqrestore(&eeh_eventlist_lock, flags);
if (event == NULL)
break;
printk(KERN_INFO "EEH: Detected PCI bus error on device %s\n",
pci_name(event->dev));
eeh_panic (event->dev, event->state);
kfree(event);
}
return 0;
}
/**
* eeh_thread_launcher
*
* @dummy - unused
*/
static void eeh_thread_launcher(void *dummy)
{
if (kernel_thread(eeh_event_handler, NULL, CLONE_KERNEL) < 0)
printk(KERN_ERR "Failed to start EEH daemon\n");
}
/**
* eeh_send_failure_event - generate a PCI error event
* @dev pci device
*
* This routine can be called within an interrupt context;
* the actual event will be delivered in a normal context
* (from a workqueue).
*/
int eeh_send_failure_event (struct device_node *dn,
struct pci_dev *dev,
int state,
int time_unavail)
{
unsigned long flags;
struct eeh_event *event;
event = kmalloc(sizeof(*event), GFP_ATOMIC);
if (event == NULL) {
printk (KERN_ERR "EEH: out of memory, event not handled\n");
return 1;
}
if (dev)
pci_dev_get(dev);
event->dn = dn;
event->dev = dev;
event->state = state;
event->time_unavail = time_unavail;
/* We may or may not be called in an interrupt context */
spin_lock_irqsave(&eeh_eventlist_lock, flags);
list_add(&event->list, &eeh_eventlist);
spin_unlock_irqrestore(&eeh_eventlist_lock, flags);
schedule_work(&eeh_event_wq);
return 0;
}
/********************** END OF FILE ******************************/
