ipmi_watchdog: restore settings when BMC reset

If the BMC gets reset, it will return 0x80 response errors.

In less than a week
# grep "Error 80 on cmd 22" /var/log/kernel |wc -l
378681

In this case, it is probably a good idea to restore the IPMI settings.
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Tested-by: Arkadiusz Miśkiewicz <a.miskiewicz@gmail.com>
Reported-by: Arkadiusz Miśkiewicz <a.miskiewicz@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/char/ipmi/ipmi_watchdog.c

@@ -139,6 +139,8 @@
 #define IPMI_WDOG_SET_TIMER		0x24
 #define IPMI_WDOG_GET_TIMER		0x25
 
+#define IPMI_WDOG_TIMER_NOT_INIT_RESP	0x80
+
 /* These are here until the real ones get into the watchdog.h interface. */
 #ifndef WDIOC_GETTIMEOUT
 #define	WDIOC_GETTIMEOUT        _IOW(WATCHDOG_IOCTL_BASE, 20, int)
@@ -596,6 +598,7 @@ static int ipmi_heartbeat(void)
 	struct kernel_ipmi_msg            msg;
 	int                               rv;
 	struct ipmi_system_interface_addr addr;
+	int				  timeout_retries = 0;
 
 	if (ipmi_ignore_heartbeat)
 		return 0;
@@ -616,6 +619,7 @@ static int ipmi_heartbeat(void)
 
 	mutex_lock(&heartbeat_lock);
 
+restart:
 	atomic_set(&heartbeat_tofree, 2);
 
 	/*
@@ -653,7 +657,33 @@ static int ipmi_heartbeat(void)
 	/* Wait for the heartbeat to be sent. */
 	wait_for_completion(&heartbeat_wait);
 
-	if (heartbeat_recv_msg.msg.data[0] != 0) {
+	if (heartbeat_recv_msg.msg.data[0] == IPMI_WDOG_TIMER_NOT_INIT_RESP)  {
+		timeout_retries++;
+		if (timeout_retries > 3) {
+			printk(KERN_ERR PFX ": Unable to restore the IPMI"
+			       " watchdog's settings, giving up.\n");
+			rv = -EIO;
+			goto out_unlock;
+		}
+
+		/*
+		 * The timer was not initialized, that means the BMC was
+		 * probably reset and lost the watchdog information.  Attempt
+		 * to restore the timer's info.  Note that we still hold
+		 * the heartbeat lock, to keep a heartbeat from happening
+		 * in this process, so must say no heartbeat to avoid a
+		 * deadlock on this mutex.
+		 */
+		rv = ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
+		if (rv) {
+			printk(KERN_ERR PFX ": Unable to send the command to"
+			       " set the watchdog's settings, giving up.\n");
+			goto out_unlock;
+		}
+
+		/* We might need a new heartbeat, so do it now */
+		goto restart;
+	} else if (heartbeat_recv_msg.msg.data[0] != 0) {
 		/*
 		 * Got an error in the heartbeat response.  It was already
 		 * reported in ipmi_wdog_msg_handler, but we should return
@@ -662,6 +692,7 @@ static int ipmi_heartbeat(void)
 		rv = -EINVAL;
 	}
 
+out_unlock:
 	mutex_unlock(&heartbeat_lock);
 
 	return rv;
@@ -922,11 +953,15 @@ static struct miscdevice ipmi_wdog_miscdev = {
 static void ipmi_wdog_msg_handler(struct ipmi_recv_msg *msg,
 				  void                 *handler_data)
 {
-	if (msg->msg.data[0] != 0) {
+	if (msg->msg.cmd == IPMI_WDOG_RESET_TIMER &&
+			msg->msg.data[0] == IPMI_WDOG_TIMER_NOT_INIT_RESP)
+		printk(KERN_INFO PFX "response: The IPMI controller appears"
+		       " to have been reset, will attempt to reinitialize"
+		       " the watchdog timer\n");
+	else if (msg->msg.data[0] != 0)
 		printk(KERN_ERR PFX "response: Error %x on cmd %x\n",
 		       msg->msg.data[0],
 		       msg->msg.cmd);
-	}
 
 	ipmi_free_recv_msg(msg);
 }