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