powerpc: Add support for using doorbells for SMP IPI
The e500mc supports the new msgsnd/doorbell mechanisms that were added in
the Power ISA 2.05 architecture. We use the normal level doorbell for
doing SMP IPIs at this point.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/kernel/dbell.c b/arch/powerpc/kernel/dbell.c
new file mode 100644
index 0000000..1493734
--- /dev/null
+++ b/arch/powerpc/kernel/dbell.c
@@ -0,0 +1,44 @@
+/*
+ * Author: Kumar Gala <galak@kernel.crashing.org>
+ *
+ * Copyright 2009 Freescale Semiconductor Inc.
+ *
+ * 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/stddef.h>
+#include <linux/kernel.h>
+#include <linux/smp.h>
+#include <linux/threads.h>
+
+#include <asm/dbell.h>
+
+#ifdef CONFIG_SMP
+unsigned long dbell_smp_message[NR_CPUS];
+
+void smp_dbell_message_pass(int target, int msg)
+{
+ int i;
+
+ if(target < NR_CPUS) {
+ set_bit(msg, &dbell_smp_message[target]);
+ ppc_msgsnd(PPC_DBELL, 0, target);
+ }
+ else if(target == MSG_ALL_BUT_SELF) {
+ for_each_online_cpu(i) {
+ if (i == smp_processor_id())
+ continue;
+ set_bit(msg, &dbell_smp_message[i]);
+ ppc_msgsnd(PPC_DBELL, 0, i);
+ }
+ }
+ else { /* target == MSG_ALL */
+ for_each_online_cpu(i)
+ set_bit(msg, &dbell_smp_message[i]);
+ ppc_msgsnd(PPC_DBELL, PPC_DBELL_MSG_BRDCAST, 0);
+ }
+}
+#endif