[PATCH] SN: Handle SC env. powerdown events

[Aaron Young <ayoung@google.engr.sgi.com>]

Handle system controller power down pending events
on SN systems. This allows the system to gracefully shutdown
before the system controller removes power due to
an adverse environmental condition.

Signed-off-by: Aaron Young <ayoung@sgi.com>

---

Index: linux/drivers/char/snsc.h
=================================--- linux.orig/drivers/char/snsc.h	2006-01-02 21:21:10 -06:00
+++ linux/drivers/char/snsc.h	2006-01-19 18:26:50 -06:00
@@ -5,7 +5,7 @@
  * License.  See the file "COPYING" in the main directory of this archive
  * for more details.
  *
- * Copyright (C) 2004 Silicon Graphics, Inc. All rights reserved.
+ * Copyright (C) 2004-2006 Silicon Graphics, Inc. All rights reserved.
  */
 
 /*
@@ -69,6 +69,9 @@ struct sysctl_data_s {
 #define EV_CLASS_TEST_FAULT	0x5000ul
 #define EV_CLASS_TEST_WARNING	0x6000ul
 #define EV_CLASS_PWRD_NOTIFY	0x8000ul
+
+/* ENV class codes */
+#define ENV_PWRDN_PEND		0x4101ul
 
 #define EV_SEVERITY_POWER_STABLE	0x0000ul
 #define EV_SEVERITY_POWER_LOW_WARNING	0x0100ul
Index: linux/drivers/char/snsc_event.c
=================================--- linux.orig/drivers/char/snsc_event.c	2006-01-02 21:21:10 -06:00
+++ linux/drivers/char/snsc_event.c	2006-01-20 10:26:38 -06:00
@@ -5,7 +5,7 @@
  * License.  See the file "COPYING" in the main directory of this archive
  * for more details.
  *
- * Copyright (C) 2004 Silicon Graphics, Inc. All rights reserved.
+ * Copyright (C) 2004-2006 Silicon Graphics, Inc. All rights reserved.
  */
 
 /*
@@ -187,7 +187,8 @@ scdrv_event_severity(int code)
 static void
 scdrv_dispatch_event(char *event, int len)
 {
-	int code, esp_code, src;
+	static int snsc_shutting_down = 0;
+	int code, esp_code, src, class;
 	char desc[CHUNKSIZE];
 	char *severity;
 
@@ -199,23 +200,38 @@ scdrv_dispatch_event(char *event, int le
 	/* how urgent is the message? */
 	severity = scdrv_event_severity(code);
 
-	if ((code & EV_CLASS_MASK) = EV_CLASS_PWRD_NOTIFY) {
+	class = (code & EV_CLASS_MASK);
+
+	if (class = EV_CLASS_PWRD_NOTIFY || code = ENV_PWRDN_PEND) {
 		struct task_struct *p;
 
+		if (snsc_shutting_down)
+			return;
+
+		snsc_shutting_down = 1;
+
+		/* give a message for each type of event */
+		if (class = EV_CLASS_PWRD_NOTIFY)
+			printk(KERN_NOTICE "Power off indication received."
+			    " Sending SIGPWR to init...\n");
+		else if (code = ENV_PWRDN_PEND)
+			printk(KERN_CRIT "WARNING: Shutting down the system"
+			    " due to a critical environmental condition."
+			    " Sending SIGPWR to init...\n");
+
 		/* give a SIGPWR signal to init proc */
 
 		/* first find init's task */
 		read_lock(&tasklist_lock);
 		for_each_process(p) {
-			if (p->pid = 1)
+			if (p->pid = 1) /* init's pid is well known to be 1 */
 				break;
 		}
 		if (p) { /* we found init's task */
-			printk(KERN_EMERG "Power off indication received. Initiating power fail sequence...\n");
 			force_sig(SIGPWR, p);
-		} else { /* failed to find init's task - just give message(s) */
-			printk(KERN_WARNING "Failed to find init proc to handle power off!\n");
-			printk("%s|$(0x%x)%s\n", severity, esp_code, desc);
+		} else { /* failed to find init's task */
+			printk(KERN_ERR "Failed to signal init!\n");
+			snsc_shutting_down = 0; /* so can try again (?) */
 		}
 		read_unlock(&tasklist_lock);
 	} else {