[PATCH 1/2] powerpc/powernv: Enhance opal message read interface

[Vasant Hegde <hegdevasant@linux.vnet.ibm.com>]

Use "opal-msg-size" device tree property to allocate memory for "opal_msg".

Also replace `reserved` field in "struct opal_msg" with `size`. So that
opal_get_msg() user can get actual message size.

Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Cc: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/opal-api.h   |  2 +-
 arch/powerpc/platforms/powernv/opal.c | 30 ++++++++++++++++++++----------
 2 files changed, 21 insertions(+), 11 deletions(-)

diff --git a/arch/powerpc/include/asm/opal-api.h b/arch/powerpc/include/asm/opal-api.h
index 870fb7b239ea..821ed4fa95ad 100644
--- a/arch/powerpc/include/asm/opal-api.h
+++ b/arch/powerpc/include/asm/opal-api.h
@@ -460,7 +460,7 @@ enum opal_msg_type {
 
 struct opal_msg {
 	__be32 msg_type;
-	__be32 reserved;
+	__be32 size;
 	__be64 params[8];
 };
 
diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c
index 2b0eca104f86..52fb52c2ca4b 100644
--- a/arch/powerpc/platforms/powernv/opal.c
+++ b/arch/powerpc/platforms/powernv/opal.c
@@ -62,6 +62,8 @@ static DEFINE_SPINLOCK(opal_write_lock);
 static struct atomic_notifier_head opal_msg_notifier_head[OPAL_MSG_TYPE_MAX];
 static uint32_t opal_heartbeat;
 static struct task_struct *kopald_tsk;
+static struct opal_msg *opal_msg;
+static uint64_t opal_msg_size;
 
 void opal_configure_cores(void)
 {
@@ -268,14 +270,9 @@ static void opal_message_do_notify(uint32_t msg_type, void *msg)
 static void opal_handle_message(void)
 {
 	s64 ret;
-	/*
-	 * TODO: pre-allocate a message buffer depending on opal-msg-size
-	 * value in /proc/device-tree.
-	 */
-	static struct opal_msg msg;
 	u32 type;
 
-	ret = opal_get_msg(__pa(&msg), sizeof(msg));
+	ret = opal_get_msg(__pa(opal_msg), opal_msg_size);
 	/* No opal message pending. */
 	if (ret == OPAL_RESOURCE)
 		return;
@@ -287,14 +284,14 @@ static void opal_handle_message(void)
 		return;
 	}
 
-	type = be32_to_cpu(msg.msg_type);
+	type = be32_to_cpu(opal_msg->msg_type);
 
 	/* Sanity check */
 	if (type >= OPAL_MSG_TYPE_MAX) {
 		pr_warn_once("%s: Unknown message type: %u\n", __func__, type);
 		return;
 	}
-	opal_message_do_notify(type, (void *)&msg);
+	opal_message_do_notify(type, (void *)opal_msg);
 }
 
 static irqreturn_t opal_message_notify(int irq, void *data)
@@ -303,9 +300,22 @@ static irqreturn_t opal_message_notify(int irq, void *data)
 	return IRQ_HANDLED;
 }
 
-static int __init opal_message_init(void)
+static int __init opal_message_init(struct device_node *opal_node)
 {
 	int ret, i, irq;
+	const __be32 *val;
+
+	val = of_get_property(opal_node, "opal-msg-size", NULL);
+	if (val)
+		opal_msg_size = be32_to_cpup(val);
+
+	/* If opal-msg-size property is not available then use default size */
+	if (!opal_msg_size)
+		opal_msg_size = sizeof(struct opal_msg);
+
+	opal_msg = kmalloc(opal_msg_size, GFP_KERNEL);
+	if (!opal_msg)
+		return -ENOMEM;
 
 	for (i = 0; i < OPAL_MSG_TYPE_MAX; i++)
 		ATOMIC_INIT_NOTIFIER_HEAD(&opal_msg_notifier_head[i]);
@@ -886,7 +896,7 @@ static int __init opal_init(void)
 	}
 
 	/* Initialise OPAL messaging system */
-	opal_message_init();
+	opal_message_init(opal_node);
 
 	/* Initialise OPAL asynchronous completion interface */
 	opal_async_comp_init();
-- 
2.14.3