| /* |
| * 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/mutex.h> |
| #include <linux/sched.h> |
| #include <linux/pci.h> |
| #include <linux/slab.h> |
| #include <linux/workqueue.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. |
| */ |
| |
| /* EEH event workqueue setup. */ |
| static DEFINE_SPINLOCK(eeh_eventlist_lock); |
| LIST_HEAD(eeh_eventlist); |
| static void eeh_thread_launcher(struct work_struct *); |
| DECLARE_WORK(eeh_event_wq, eeh_thread_launcher); |
| |
| /* Serialize reset sequences for a given pci device */ |
| DEFINE_MUTEX(eeh_event_mutex); |
| |
| /** |
| * 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; |
| |
| set_task_comm(current, "eehd"); |
| |
| spin_lock_irqsave(&eeh_eventlist_lock, flags); |
| event = NULL; |
| |
| /* Unqueue the event, get ready to process. */ |
| 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) |
| return 0; |
| |
| /* Serialize processing of EEH events */ |
| mutex_lock(&eeh_event_mutex); |
| pe = event->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); |
| |
| set_current_state(TASK_INTERRUPTIBLE); /* Don't add to load average */ |
| handle_eeh_events(event); |
| eeh_pe_state_clear(pe, EEH_PE_RECOVERING); |
| |
| kfree(event); |
| mutex_unlock(&eeh_event_mutex); |
| |
| /* If there are no new errors after an hour, clear the counter. */ |
| if (pe && pe->freeze_count > 0) { |
| msleep_interruptible(3600*1000); |
| if (pe->freeze_count > 0) |
| pe->freeze_count--; |
| |
| } |
| |
| return 0; |
| } |
| |
| /** |
| * eeh_thread_launcher - Start kernel thread to handle EEH events |
| * @dummy - unused |
| * |
| * This routine is called to start the kernel thread for processing |
| * EEH event. |
| */ |
| static void eeh_thread_launcher(struct work_struct *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 |
| * @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); |
| |
| schedule_work(&eeh_event_wq); |
| |
| return 0; |
| } |