powerpc/powernv: Add OPAL soft-poweroff routine

Register a notifier for a OPAL message indicating that the machine
should prepare itself for a graceful power off.

OPAL will tell us if the power off is a reboot or shutdown, but for now
we perform the same orderly_poweroff action.
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/include/asm/opal.h

@@ -304,7 +304,7 @@ enum OpalMessageType {
 					 */
 	OPAL_MSG_MEM_ERR,
 	OPAL_MSG_EPOW,
-	OPAL_MSG_SHUTDOWN,
+	OPAL_MSG_SHUTDOWN,		/* params[0] = 1 reboot, 0 shutdown */
 	OPAL_MSG_HMI_EVT,
 	OPAL_MSG_TYPE_MAX,
 };

arch/powerpc/platforms/powernv/Makefile

 obj-y			+= setup.o opal-wrappers.o opal.o opal-async.o
 obj-y			+= opal-rtc.o opal-nvram.o opal-lpc.o opal-flash.o
 obj-y			+= rng.o opal-elog.o opal-dump.o opal-sysparam.o opal-sensor.o
-obj-y			+= opal-msglog.o opal-hmi.o
+obj-y			+= opal-msglog.o opal-hmi.o opal-power.o
 
 obj-$(CONFIG_SMP)	+= smp.o subcore.o subcore-asm.o
 obj-$(CONFIG_PCI)	+= pci.o pci-p5ioc2.o pci-ioda.o

arch/powerpc/platforms/powernv/opal-power.c

+/*
+ * PowerNV OPAL power control for graceful shutdown handling
+ *
+ * Copyright 2015 IBM Corp.
+ *
+ * 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; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/reboot.h>
+#include <linux/notifier.h>
+
+#include <asm/opal.h>
+#include <asm/machdep.h>
+
+#define SOFT_OFF 0x00
+#define SOFT_REBOOT 0x01
+
+static int opal_power_control_event(struct notifier_block *nb,
+				    unsigned long msg_type, void *msg)
+{
+	struct opal_msg *power_msg = msg;
+	uint64_t type;
+
+	type = be64_to_cpu(power_msg->params[0]);
+
+	switch (type) {
+	case SOFT_REBOOT:
+		/* Fall through. The service processor is responsible for
+		 * bringing the machine back up */
+	case SOFT_OFF:
+		pr_info("OPAL: poweroff requested\n");
+		orderly_poweroff(true);
+		break;
+	default:
+		pr_err("OPAL: power control type unexpected %016llx\n", type);
+	}
+
+	return 0;
+}
+
+static struct notifier_block opal_power_control_nb = {
+	.notifier_call	= opal_power_control_event,
+	.next		= NULL,
+	.priority	= 0,
+};
+
+static int __init opal_power_control_init(void)
+{
+	int ret;
+
+	ret = opal_message_notifier_register(OPAL_MSG_SHUTDOWN,
+					     &opal_power_control_nb);
+	if (ret) {
+		pr_err("%s: Can't register OPAL event notifier (%d)\n",
+				__func__, ret);
+		return ret;
+	}
+
+	return 0;
+}
+machine_subsys_initcall(powernv, opal_power_control_init);