powerpc/powernv: Enhance opal message read interface

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

Signed-off-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
[mpe: s/uint32_t/u32/ and mark opal_msg_size as __ro_after_init]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190826065701.8853-1-hegdevasant@linux.vnet.ibm.com

diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c
index d271acc..38e9027 100644 (file)
--- a/arch/powerpc/platforms/powernv/opal.c
+++ b/arch/powerpc/platforms/powernv/opal.c
@@ -58,6 +58,8 @@ 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 u32 opal_msg_size __ro_after_init;
 
 void opal_configure_cores(void)
 {
@@ -271,14 +273,9 @@ 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;
@@ -290,14 +287,14 @@ 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)
@@ -306,10 +303,24 @@ 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;
 
+       ret = of_property_read_u32(opal_node, "opal-msg-size", &opal_msg_size);
+       if (ret) {
+               pr_notice("Failed to read opal-msg-size property\n");
+               opal_msg_size = sizeof(struct opal_msg);
+       }
+
+       opal_msg = kmalloc(opal_msg_size, GFP_KERNEL);
+       if (!opal_msg) {
+               opal_msg_size = sizeof(struct opal_msg);
+               /* Try to allocate fixed message size */
+               opal_msg = kmalloc(opal_msg_size, GFP_KERNEL);
+               BUG_ON(opal_msg == NULL);
+       }
+
        for (i = 0; i < OPAL_MSG_TYPE_MAX; i++)
                ATOMIC_INIT_NOTIFIER_HEAD(&opal_msg_notifier_head[i]);
 
@@ -913,7 +924,7 @@ 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();