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/slab.h> 26#include <linux/workqueue.h> 27#include <asm/eeh_event.h> 28#include <asm/ppc-pci.h> 29 30/** Overview: 31 * EEH error states may be detected within exception handlers; 32 * however, the recovery processing needs to occur asynchronously 33 * in a normal kernel context and not an interrupt context. 34 * This pair of routines creates an event and queues it onto a 35 * work-queue, where a worker thread can drive recovery. 36 */ 37 38/* EEH event workqueue setup. */ 39static DEFINE_SPINLOCK(eeh_eventlist_lock); 40LIST_HEAD(eeh_eventlist); 41static void eeh_thread_launcher(struct work_struct *); 42DECLARE_WORK(eeh_event_wq, eeh_thread_launcher); 43 44/* Serialize reset sequences for a given pci device */ 45DEFINE_MUTEX(eeh_event_mutex); 46 47/** 48 * eeh_event_handler - dispatch EEH events. 49 * @dummy - unused 50 * 51 * The detection of a frozen slot can occur inside an interrupt, 52 * where it can be hard to do anything about it. The goal of this 53 * routine is to pull these detection events out of the context 54 * of the interrupt handler, and re-dispatch them for processing 55 * at a later time in a normal context. 56 */ 57static int eeh_event_handler(void * dummy) 58{ 59 unsigned long flags; 60 struct eeh_event *event; 61 struct pci_dn *pdn; 62 63 daemonize ("eehd"); 64 set_current_state(TASK_INTERRUPTIBLE); 65 66 spin_lock_irqsave(&eeh_eventlist_lock, flags); 67 event = NULL; 68 69 /* Unqueue the event, get ready to process. */ 70 if (!list_empty(&eeh_eventlist)) { 71 event = list_entry(eeh_eventlist.next, struct eeh_event, list); 72 list_del(&event->list); 73 } 74 spin_unlock_irqrestore(&eeh_eventlist_lock, flags); 75 76 if (event == NULL) 77 return 0; 78 79 /* Serialize processing of EEH events */ 80 mutex_lock(&eeh_event_mutex); 81 eeh_mark_slot(event->dn, EEH_MODE_RECOVERING); 82 83 printk(KERN_INFO "EEH: Detected PCI bus error on device %s\n", 84 eeh_pci_name(event->dev)); 85 86 pdn = handle_eeh_events(event); 87 88 eeh_clear_slot(event->dn, EEH_MODE_RECOVERING); 89 pci_dev_put(event->dev); 90 kfree(event); 91 mutex_unlock(&eeh_event_mutex); 92 93 /* If there are no new errors after an hour, clear the counter. */ 94 if (pdn && pdn->eeh_freeze_count>0) { 95 msleep_interruptible (3600*1000); 96 if (pdn->eeh_freeze_count>0) 97 pdn->eeh_freeze_count--; 98 } 99 100 return 0; 101} 102 103/** 104 * eeh_thread_launcher 105 * @dummy - unused 106 */ 107static void eeh_thread_launcher(struct work_struct *dummy) 108{ 109 if (kernel_thread(eeh_event_handler, NULL, CLONE_KERNEL) < 0) 110 printk(KERN_ERR "Failed to start EEH daemon\n"); 111} 112 113/** 114 * eeh_send_failure_event - generate a PCI error event 115 * @dev pci device 116 * 117 * This routine can be called within an interrupt context; 118 * the actual event will be delivered in a normal context 119 * (from a workqueue). 120 */ 121int eeh_send_failure_event (struct device_node *dn, 122 struct pci_dev *dev) 123{ 124 unsigned long flags; 125 struct eeh_event *event; 126 const char *location; 127 128 if (!mem_init_done) { 129 printk(KERN_ERR "EEH: event during early boot not handled\n"); 130 location = of_get_property(dn, "ibm,loc-code", NULL); 131 printk(KERN_ERR "EEH: device node = %s\n", dn->full_name); 132 printk(KERN_ERR "EEH: PCI location = %s\n", location); 133 return 1; 134 } 135 event = kmalloc(sizeof(*event), GFP_ATOMIC); 136 if (event == NULL) { 137 printk (KERN_ERR "EEH: out of memory, event not handled\n"); 138 return 1; 139 } 140 141 if (dev) 142 pci_dev_get(dev); 143 144 event->dn = dn; 145 event->dev = dev; 146 147 /* We may or may not be called in an interrupt context */ 148 spin_lock_irqsave(&eeh_eventlist_lock, flags); 149 list_add(&event->list, &eeh_eventlist); 150 spin_unlock_irqrestore(&eeh_eventlist_lock, flags); 151 152 schedule_work(&eeh_event_wq); 153 154 return 0; 155} 156 157/********************** END OF FILE ******************************/ 158