[PATCH] powerpc/powernv: Support OPAL requested heartbeat

[Benjamin Herrenschmidt <benh@kernel.crashing.org>]

If OPAL requests it, call it back via opal_poll_events() at a
regular interval. Some versions of OPAL on some machines require
this to operate some internal timeouts properly.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---
 arch/powerpc/platforms/powernv/opal.c | 64 ++++++++++++++++++++++++++++++-----
 1 file changed, 55 insertions(+), 9 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c
index f1e0d8c..0153064 100644
--- a/arch/powerpc/platforms/powernv/opal.c
+++ b/arch/powerpc/platforms/powernv/opal.c
@@ -22,6 +22,8 @@
 #include <linux/kobject.h>
 #include <linux/delay.h>
 #include <linux/memblock.h>
+#include <linux/kthread.h>
+#include <linux/freezer.h>
 
 #include <asm/machdep.h>
 #include <asm/opal.h>
@@ -58,6 +60,7 @@ static struct atomic_notifier_head opal_msg_notifier_head[OPAL_MSG_TYPE_MAX];
 static DEFINE_SPINLOCK(opal_notifier_lock);
 static uint64_t last_notified_mask = 0x0ul;
 static atomic_t opal_notifier_hold = ATOMIC_INIT(0);
+static uint32_t opal_heartbeat;
 
 static void opal_reinit_cores(void)
 {
@@ -633,17 +636,9 @@ static void opal_ipmi_init(struct device_node *opal_node)
 			of_platform_device_create(np, NULL, NULL);
 }
 
-static int __init opal_init(void)
+static void opal_console_create_devs(void)
 {
 	struct device_node *np, *consoles;
-	const __be32 *irqs;
-	int rc, i, irqlen;
-
-	opal_node = of_find_node_by_path("/ibm,opal");
-	if (!opal_node) {
-		pr_warn("opal: Node not found\n");
-		return -ENODEV;
-	}
 
 	/* Register OPAL consoles if any ports */
 	if (firmware_has_feature(FW_FEATURE_OPALv2))
@@ -659,6 +654,13 @@ static int __init opal_init(void)
 		of_node_put(consoles);
 	}
 
+}
+
+static void opal_request_interrupts(void)
+{
+	const __be32 *irqs;
+	int rc, i, irqlen;
+
 	/* Find all OPAL interrupts and request them */
 	irqs = of_get_property(opal_node, "opal-interrupts", &irqlen);
 	pr_debug("opal: Found %d interrupts reserved for OPAL\n",
@@ -678,6 +680,49 @@ static int __init opal_init(void)
 				   " (0x%x)\n", rc, irq, hwirq);
 		opal_irqs[i] = irq;
 	}
+}
+
+static int kopald(void *unused)
+{
+	set_freezable();
+	do {
+		try_to_freeze();
+		opal_poll_events(NULL);
+		msleep_interruptible(opal_heartbeat);
+	} while (!kthread_should_stop());
+
+	return 0;
+}
+
+static void opal_init_heartbeat(void)
+{
+	/* Old firwmware, we assume the HVC heartbeat is sufficient */
+	if (of_property_read_u32(opal_node, "ibm,heartbeat-freq",
+				 &opal_heartbeat) != 0)
+		opal_heartbeat = 0;
+
+	if (opal_heartbeat)
+		kthread_run(kopald, NULL, "kopald");
+}
+
+static int __init opal_init(void)
+{
+	int rc;
+
+	opal_node = of_find_node_by_path("/ibm,opal");
+	if (!opal_node) {
+		pr_warn("opal: Node not found\n");
+		return -ENODEV;
+	}
+
+	/* Setup a heatbeat thread if requested by OPAL */
+	opal_init_heartbeat();
+
+	/* Create console platform devices */
+	opal_console_create_devs();
+
+	/* Register OPAL interrupts */
+	opal_request_interrupts();
 
 	/* Create "opal" kobject under /sys/firmware */
 	rc = opal_sysfs_init();
@@ -696,6 +741,7 @@ static int __init opal_init(void)
 		opal_msglog_init();
 	}
 
+	/* Initialize OPAL IPMI backend */
 	opal_ipmi_init(opal_node);
 
 	return 0;