Re: [PATCH]Enabling Auto poweron after power is restored.

[Manish Ahuja <ahuja@austin.ibm.com>]

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Resubmitting this patch with a sysfs interface instead of /proc.
During some off line discussion, /sys/power was suggested as a possible 
candidate area for this functionality to reside.

-------------------------------------------------------------------------------------------------------------------------

During power outages, the ups notifies the system for a shutdown. In the 
current setup, it isn't possible to poweron when power is restored. This 
patch fixes the issue by calling the right ibm,power-off-ups token 
during such events. It also adds a sysfs interface so that rc.powerfail 
can parse the epow events and modify the power-off behavior accordingly 
to enable the right token to be called.

Signed-off-by: Manish Ahuja <ahuja@austin.ibm.com>


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Index: 2.6.20-rc6-git1-t2/arch/powerpc/kernel/rtas.c
===================================================================
--- 2.6.20-rc6-git1-t2.orig/arch/powerpc/kernel/rtas.c	2007-02-02 05:47:13.000000000 -0800
+++ 2.6.20-rc6-git1-t2/arch/powerpc/kernel/rtas.c	2007-02-02 08:37:09.000000000 -0800
@@ -607,13 +607,31 @@
 	for (;;);
 }
 
+/**
+ * rtas_power_off - tell firmware about how to power off the system.
+ *
+ * This function calls either the power-off rtas token in normal cases
+ * or the ibm,power-off-ups token (if present & requested) in case of
+ * a power failure. If power-off token is used, power on will only be
+ * possible with power button press. If ibm,power-off-ups token is used
+ * it will allow auto poweron after power is restored.
+ */
 void rtas_power_off(void)
 {
+	int rc;
+	int rtas_poweroff_ups_token = rtas_token("ibm,power-off-ups");
+
 	if (rtas_flash_term_hook)
-		rtas_flash_term_hook(SYS_POWER_OFF);
-	/* allow power on only with power button press */
-	printk("RTAS power-off returned %d\n",
-	       rtas_call(rtas_token("power-off"), 2, 1, NULL, -1, -1));
+	rtas_flash_term_hook(SYS_POWER_OFF);
+
+	if (rtas_poweron_auto == 0 ||
+		rtas_poweroff_ups_token == RTAS_UNKNOWN_SERVICE) {
+		rc = rtas_call(rtas_token("power-off"), 2, 1, NULL, -1, -1);
+		printk(KERN_INFO "RTAS power-off returned %d\n", rc);
+	} else {
+		rc = rtas_call(rtas_poweroff_ups_token, 0, 1, NULL);
+		printk(KERN_INFO "RTAS ibm,power-off-ups returned %d\n", rc);
+	}
 	for (;;);
 }
 
Index: 2.6.20-rc6-git1-t2/include/asm-powerpc/rtas.h
===================================================================
--- 2.6.20-rc6-git1-t2.orig/include/asm-powerpc/rtas.h	2007-02-02 05:47:32.000000000 -0800
+++ 2.6.20-rc6-git1-t2/include/asm-powerpc/rtas.h	2007-02-02 08:39:25.000000000 -0800
@@ -225,6 +225,9 @@
 /* RMO buffer reserved for user-space RTAS use */
 extern unsigned long rtas_rmo_buf;
 
+/* Poweron buffer used for enabling auto ups restart */
+extern unsigned long rtas_poweron_auto;
+
 #define GLOBAL_INTERRUPT_QUEUE 9005
 
 /**
Index: 2.6.20-rc6-git1-t2/arch/powerpc/platforms/pseries/power.c
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ 2.6.20-rc6-git1-t2/arch/powerpc/platforms/pseries/power.c	2007-02-02 13:18:09.000000000 -0800
@@ -0,0 +1,87 @@
+/*
+ *  Interface for power-management for ppc64 compliant platform
+ *
+ *  Manish Ahuja <mahuja@us.ibm.com>
+ *
+ *  Feb 2007
+ *
+ *  Copyright (C) 2007 IBM Corporation.
+ *
+ *  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; version 2 of the License.
+ *
+ *  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
+ */
+
+#include <linux/kobject.h>
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+
+unsigned long rtas_poweron_auto; /* default and normal state is 0 */
+
+static ssize_t auto_poweron_show(struct subsystem * subsys, char * buf)
+{
+        return sprintf(buf, "%lu\n", rtas_poweron_auto);
+}
+
+static ssize_t
+auto_poweron_store(struct subsystem * subsys, const char * buf, size_t n)
+{
+	int ret;
+	unsigned long ups_restart;
+	ret = sscanf(buf, "%lu", &ups_restart);
+
+	if ((ret == 1) && ((ups_restart == 1) || (ups_restart == 0))){
+		rtas_poweron_auto = ups_restart;
+		return n;
+	}
+	return -EINVAL;
+}
+
+static struct subsys_attribute auto_poweron_attr = {
+        .attr   = {
+                .name = __stringify(auto_poweron),
+                .mode = 0644,
+        },
+        .show   = auto_poweron_show,
+        .store  = auto_poweron_store,
+};
+
+#ifndef CONFIG_PM
+decl_subsys(power,NULL,NULL);
+
+static struct attribute * g[] = {
+        &auto_poweron_attr.attr,
+        NULL,
+};
+
+static struct attribute_group attr_group = {
+        .attrs = g,
+};
+
+static int __init pm_init(void)
+{
+        int error = subsystem_register(&power_subsys);
+        if (!error)
+                error = sysfs_create_group(&power_subsys.kset.kobj,&attr_group);
+        return error;
+}
+core_initcall(pm_init);
+#else
+extern struct subsystem power_subsys;
+
+static int __init apo_pm_init(void)
+{
+	return(subsys_create_file(&power_subsys, &auto_poweron_attr));
+}
+__initcall(apo_pm_init);
+#endif
Index: 2.6.20-rc6-git1-t2/arch/powerpc/platforms/pseries/Makefile
===================================================================
--- 2.6.20-rc6-git1-t2.orig/arch/powerpc/platforms/pseries/Makefile	2007-02-02 05:47:13.000000000 -0800
+++ 2.6.20-rc6-git1-t2/arch/powerpc/platforms/pseries/Makefile	2007-02-02 09:32:09.000000000 -0800
@@ -4,7 +4,7 @@
 
 obj-y			:= pci.o lpar.o hvCall.o nvram.o reconfig.o \
 			   setup.o iommu.o ras.o rtasd.o pci_dlpar.o \
-			   firmware.o
+			   firmware.o power.o
 obj-$(CONFIG_SMP)	+= smp.o
 obj-$(CONFIG_XICS)	+= xics.o
 obj-$(CONFIG_SCANLOG)	+= scanlog.o