Subject: [PATCH v3] powerpc/powernv: Add poweroff (EPOW, DPO) events support for PowerNV platform

From: Vipin K Parashar <[email-masked]>
Date: Thu, 14 May 2015 16:16:59 +0530

This patch adds support for FSP EPOW (Early Power Off Warning) and
DPO (Delayed Power Off) events support for PowerNV platform. EPOW events
are generated by SPCN/FSP due to various critical system conditions that
need system shutdown. Few examples of these conditions are high ambient
temperature or system running on UPS power with low UPS battery. DPO event
is generated in response to admin initiated system shutdown request.
	Upon receipt of EPOW and DPO events host kernel invokes orderly_poweroff
for performing graceful system shutdown. System admin can also add systemd
service shutdown scripts to perform any specific actions like graceful guest
shutdown upon system poweroff. libvirt-guests is systemd service available on
recent distros for management of guests at system start/shutdown time.

Signed-off-by: Vipin K Parashar <[email-masked]>
---
 arch/powerpc/include/asm/opal-api.h            |  44 +++++++
 arch/powerpc/include/asm/opal.h                |   3 +-
 arch/powerpc/platforms/powernv/opal-power.c    | 167 ++++++++++++++++++++++---
 arch/powerpc/platforms/powernv/opal-wrappers.S |   1 +
 4 files changed, 197 insertions(+), 18 deletions(-)

diff --git a/arch/powerpc/include/asm/opal-api.h b/arch/powerpc/include/asm/opal-api.h
index 0321a90..90fa364 100644
--- a/arch/powerpc/include/asm/opal-api.h
+++ b/arch/powerpc/include/asm/opal-api.h
@@ -355,6 +355,10 @@ enum opal_msg_type {
 	OPAL_MSG_TYPE_MAX,
 };
 
+/* OPAL_MSG_SHUTDOWN parameter values */
+#define	SOFT_OFF	0x00
+#define	SOFT_REBOOT	0x01
+
 struct opal_msg {
 	__be32 msg_type;
 	__be32 reserved;
@@ -730,6 +734,46 @@ struct opal_i2c_request {
 	__be64 buffer_ra;		/* Buffer real address */
 };
 
+/*
+ * EPOW status sharing (OPAL and the host)
+ *
+ * The host will pass on OPAL, a buffer of length OPAL_SYSEPOW_MAX
+ * with individual elements being 16 bits wide to fetch the system
+ * wide EPOW status. Each element in the buffer will contain the
+ * EPOW status in it's bit representation for a particular EPOW sub
+ * class as defiend here. So multiple detailed EPOW status bits
+ * specific for any sub class can be represented in a single buffer
+ * element as it's bit representation.
+ */
+
+/* System EPOW type */
+enum OpalSysEpow {
+	OPAL_SYSEPOW_POWER	= 0,	/* Power EPOW */
+	OPAL_SYSEPOW_TEMP	= 1,	/* Temperature EPOW */
+	OPAL_SYSEPOW_COOLING	= 2,	/* Cooling EPOW */
+	OPAL_SYSEPOW_MAX	= 3,	/* Max EPOW categories */
+};
+
+/* Power EPOW */
+enum OpalSysPower {
+	OPAL_SYSPOWER_UPS	= 0x0001, /* System on UPS power */
+	OPAL_SYSPOWER_CHNG	= 0x0002, /* System power config change */
+	OPAL_SYSPOWER_FAIL	= 0x0004, /* System impending power failure */
+	OPAL_SYSPOWER_INCL	= 0x0008, /* System incomplete power */
+};
+
+/* Temperature EPOW */
+enum OpalSysTemp {
+	OPAL_SYSTEMP_AMB	= 0x0001, /* System over ambient temperature */
+	OPAL_SYSTEMP_INT	= 0x0002, /* System over internal temperature */
+	OPAL_SYSTEMP_HMD	= 0x0004, /* System over ambient humidity */
+};
+
+/* Cooling EPOW */
+enum OpalSysCooling {
+	OPAL_SYSCOOL_INSF	= 0x0001, /* System insufficient cooling */
+};
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* __OPAL_API_H */
diff --git a/arch/powerpc/include/asm/opal.h b/arch/powerpc/include/asm/opal.h
index 042af1a..d30766f 100644
--- a/arch/powerpc/include/asm/opal.h
+++ b/arch/powerpc/include/asm/opal.h
@@ -141,7 +141,8 @@ int64_t opal_pci_fence_phb(uint64_t phb_id);
 int64_t opal_pci_reinit(uint64_t phb_id, uint64_t reinit_scope, uint64_t data);
 int64_t opal_pci_mask_pe_error(uint64_t phb_id, uint16_t pe_number, uint8_t error_type, uint8_t mask_action);
 int64_t opal_set_slot_led_status(uint64_t phb_id, uint64_t slot_id, uint8_t led_type, uint8_t led_action);
-int64_t opal_get_epow_status(__be64 *status);
+int64_t opal_get_epow_status(uint16_t *status, uint16_t *length);
+int64_t opal_get_dpo_status(int64_t *dpo_timeout);
 int64_t opal_set_system_attention_led(uint8_t led_action);
 int64_t opal_pci_next_error(uint64_t phb_id, __be64 *first_frozen_pe,
 			    __be16 *pci_error_type, __be16 *severity);
diff --git a/arch/powerpc/platforms/powernv/opal-power.c b/arch/powerpc/platforms/powernv/opal-power.c
index ac46c2c..0a1e07b 100644
--- a/arch/powerpc/platforms/powernv/opal-power.c
+++ b/arch/powerpc/platforms/powernv/opal-power.c
@@ -1,5 +1,5 @@
 /*
- * PowerNV OPAL power control for graceful shutdown handling
+ * PowerNV support for OPAL power-control, poweroff events
  *
  * Copyright 2015 IBM Corp.
  *
@@ -9,40 +9,137 @@
  * 2 of the License, or (at your option) any later version.
  */
 
+#define pr_fmt(fmt)	"OPAL-POWER: "	fmt
+
 #include <linux/kernel.h>
+#include <linux/spinlock.h>
+#include <linux/timer.h>
 #include <linux/reboot.h>
-#include <linux/notifier.h>
-
+#include <linux/of.h>
 #include <asm/opal.h>
 #include <asm/machdep.h>
 
-#define SOFT_OFF 0x00
-#define SOFT_REBOOT 0x01
+/* System EPOW, DPO support variable */
+static bool epow_dpo_supported;
+
+/* System EPOW status */
+static u16 epow_status[OPAL_SYSEPOW_MAX];
+static u16 num_epow_classes;
+
+/* Get DPO status */
+static bool get_dpo_status(void)
+{
+	int rc;
+	__be64 opal_dpo_timeout;
+
+	rc = opal_get_dpo_status(&opal_dpo_timeout);
+	if (rc == OPAL_WRONG_STATE)
+		return false;
+
+	return true;
+}
+
+/* Get EPOW status */
+static bool get_epow_status(void)
+{
+	int i;
+
+	__be16 opal_epow_status[OPAL_SYSEPOW_MAX] = {0};
+	__be16 epow_classes;
+
+	/* Send kernel EPOW classes supported info to OPAL */
+	epow_classes = cpu_to_be16(OPAL_SYSEPOW_MAX);
+
+	/* Get EPOW events information from OPAL */
+	opal_get_epow_status(opal_epow_status, &epow_classes);
 
+	/* Copy EPOW status obtained from OPAL */
+	memset(epow_status, 0, sizeof(epow_status));
+	num_epow_classes = be16_to_cpu(epow_classes);
+	for (i = 0; i < num_epow_classes; i++) {
+		epow_status[i] = be16_to_cpu(opal_epow_status[i]);
+		if (epow_status[i])
+			return true;
+	}
+
+	return false;
+}
+
+/* Process existing EPOW, DPO events */
+static void process_existing_poweroff_events(void)
+{
+
+	/* Check for any existing DPO, EPOW event */
+	if (epow_dpo_supported) {
+
+		/* Check for DPO event first */
+		if (get_dpo_status()) {
+			pr_info("Existing DPO event detected. "
+				"Powering off system\n");
+			orderly_poweroff(true);
+			return;
+		}
+
+		/* EPOW event check */
+		if (get_epow_status()) {
+			pr_info("Existing EPOW event detected. "
+				"Powering off system");
+			orderly_poweroff(true);
+			return;
+		}
+	}
+}
+
+/* OPAL EPOW, DPO event notifier */
+static int opal_epow_dpo_event(struct notifier_block *nb,
+				unsigned long msg_type, void *msg)
+{
+	switch (msg_type) {
+	case OPAL_MSG_EPOW:
+		pr_info("EPOW msg received. Powering off system\n");
+		orderly_poweroff(true);
+		break;
+
+	case OPAL_MSG_DPO:
+		pr_info("DPO msg received. Powering off system\n");
+		orderly_poweroff(true);
+	}
+
+	return 0;
+}
+
+/* OPAL power-control events notifier */
 static int opal_power_control_event(struct notifier_block *nb,
-				    unsigned long msg_type, void *msg)
+				unsigned long msg_type, void *msg)
 {
-	struct opal_msg *power_msg = msg;
 	uint64_t type;
+	struct opal_msg *power_msg = msg;
 
 	type = be64_to_cpu(power_msg->params[0]);
-
 	switch (type) {
 	case SOFT_REBOOT:
-		pr_info("OPAL: reboot requested\n");
+		pr_info("Reboot requested\n");
 		orderly_reboot();
 		break;
 	case SOFT_OFF:
-		pr_info("OPAL: poweroff requested\n");
+		pr_info("Poweroff requested\n");
 		orderly_poweroff(true);
 		break;
 	default:
-		pr_err("OPAL: power control type unexpected %016llx\n", type);
+		pr_err("Unknown event %llu\n", type);
 	}
 
 	return 0;
 }
 
+/* OPAL EPOW, DPO event notifier block */
+static struct notifier_block opal_epow_dpo_nb = {
+	.notifier_call  = opal_epow_dpo_event,
+	.next           = NULL,
+	.priority       = 0,
+};
+
+/* OPAL power-control event notifier block */
 static struct notifier_block opal_power_control_nb = {
 	.notifier_call	= opal_power_control_event,
 	.next		= NULL,
@@ -52,15 +149,51 @@ static struct notifier_block opal_power_control_nb = {
 static int __init opal_power_control_init(void)
 {
 	int ret;
+	struct device_node *node_epow;
 
-	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;
+	/*
+	* Determine EPOW, DPO support in hardware.
+	*/
+	node_epow = of_find_node_by_path("/ibm,opal/epow");
+	if (node_epow) {
+		if (of_device_is_compatible(node_epow, "ibm,opal-v3-epow")) {
+			epow_dpo_supported = true;
+			pr_info("OPAL EPOW, DPO support detected.\n");
+		}
+		of_node_put(node_epow);
+	}
+
+	/* Prepare to handle EPOW, DPO events */
+	if (epow_dpo_supported) {
+
+		/* Register EPOW event notifier */
+		ret = opal_message_notifier_register(OPAL_MSG_EPOW,
+				&opal_epow_dpo_nb);
+		if (ret)
+			pr_err("EPOW event notifier registration failed, "
+					"ret = %d\n", ret);
+
+		/* Register DPO event notifier */
+		ret = opal_message_notifier_register(OPAL_MSG_DPO,
+				&opal_epow_dpo_nb);
+		if (ret)
+			pr_err("DPO event notifier registration failed, "
+					"ret = %d\n", ret);
 	}
 
+	/* Register OPAL power-control events notifier */
+	ret = opal_message_notifier_register(OPAL_MSG_SHUTDOWN,
+				&opal_power_control_nb);
+	if (ret)
+		pr_err("Power-control events notifier registration "
+				"failed, ret = %d\n", ret);
+
+	/* Check for any existing EPOW or DPO events. */
+	process_existing_poweroff_events();
+
+	pr_info("Power-control, poweroff events support initialized\n");
+
 	return 0;
 }
+
 machine_subsys_initcall(powernv, opal_power_control_init);
diff --git a/arch/powerpc/platforms/powernv/opal-wrappers.S b/arch/powerpc/platforms/powernv/opal-wrappers.S
index a7ade94..5d3c8e3 100644
--- a/arch/powerpc/platforms/powernv/opal-wrappers.S
+++ b/arch/powerpc/platforms/powernv/opal-wrappers.S
@@ -249,6 +249,7 @@ OPAL_CALL(opal_pci_reinit,			OPAL_PCI_REINIT);
 OPAL_CALL(opal_pci_mask_pe_error,		OPAL_PCI_MASK_PE_ERROR);
 OPAL_CALL(opal_set_slot_led_status,		OPAL_SET_SLOT_LED_STATUS);
 OPAL_CALL(opal_get_epow_status,			OPAL_GET_EPOW_STATUS);
+OPAL_CALL(opal_get_dpo_status,			OPAL_GET_DPO_STATUS);
 OPAL_CALL(opal_set_system_attention_led,	OPAL_SET_SYSTEM_ATTENTION_LED);
 OPAL_CALL(opal_pci_next_error,			OPAL_PCI_NEXT_ERROR);
 OPAL_CALL(opal_pci_poll,			OPAL_PCI_POLL);
-- 
1.9.3