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/*
* 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/delay.h>
#include <linux/list.h>
#include <linux/sched.h>
#include <linux/semaphore.h>
#include <linux/pci.h>
#include <linux/slab.h>
#include <linux/kthread.h>
#include <asm/eeh_event.h>
#include <asm/ppc-pci.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.
*/
static DEFINE_SPINLOCK(eeh_eventlist_lock);
static struct semaphore eeh_eventlist_sem;
LIST_HEAD(eeh_eventlist);
/**
* eeh_event_handler - Dispatch EEH events.
* @dummy - unused
*
* 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.
*/
static int eeh_event_handler(void * dummy)
{
unsigned long flags;
struct eeh_event *event;
struct eeh_pe *pe;
while (!kthread_should_stop()) {
down(&eeh_eventlist_sem);
/* Fetch EEH event from the queue */
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)
continue;
/* We might have event without binding PE */
pe = event->pe;
if (pe) {
eeh_pe_state_mark(pe, EEH_PE_RECOVERING);
pr_info("EEH: Detected PCI bus error on PHB#%d-PE#%x\n",
pe->phb->global_number, pe->addr);
eeh_handle_event(pe);
eeh_pe_state_clear(pe, EEH_PE_RECOVERING);
} else {
eeh_handle_event(NULL);
}
kfree(event);
}
return 0;
}
/**
* eeh_event_init - Start kernel thread to handle EEH events
*
* This routine is called to start the kernel thread for processing
* EEH event.
*/
int eeh_event_init(void)
{
struct task_struct *t;
int ret = 0;
/* Initialize semaphore */
sema_init(&eeh_eventlist_sem, 0);
t = kthread_run(eeh_event_handler, NULL, "eehd");
if (IS_ERR(t)) {
ret = PTR_ERR(t);
pr_err("%s: Failed to start EEH daemon (%d)\n",
__func__, ret);
return ret;
}
return 0;
}
/**
* eeh_send_failure_event - Generate a PCI error event
* @pe: EEH PE
*
* 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 eeh_pe *pe)
{
unsigned long flags;
struct eeh_event *event;
event = kzalloc(sizeof(*event), GFP_ATOMIC);
if (!event) {
pr_err("EEH: out of memory, event not handled\n");
return -ENOMEM;
}
event->pe = pe;
/* 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);
/* For EEH deamon to knick in */
up(&eeh_eventlist_sem);
return 0;
}
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