msm: scm: Add scm_call_atomic3

Some drivers need to pass three arguments atomically. Add support
for it.

Change-Id: Id0f962400c5c4f721eef44069fc3db1779248ae3
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
diff --git a/arch/arm/mach-msm/scm.c b/arch/arm/mach-msm/scm.c
index d070efa..6e05177 100644
--- a/arch/arm/mach-msm/scm.c
+++ b/arch/arm/mach-msm/scm.c
@@ -1,4 +1,4 @@
-/* Copyright (c) 2010-2012, The Linux Foundation. All rights reserved.
+/* Copyright (c) 2010-2013, The Linux Foundation. All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 and
@@ -347,6 +347,43 @@
 }
 EXPORT_SYMBOL(scm_call_atomic2);
 
+/**
+ * scm_call_atomic3() - Send an atomic SCM command with three arguments
+ * @svc_id: service identifier
+ * @cmd_id: command identifier
+ * @arg1: first argument
+ * @arg2: second argument
+ * @arg3: third argument
+ *
+ * This shall only be used with commands that are guaranteed to be
+ * uninterruptable, atomic and SMP safe.
+ */
+s32 scm_call_atomic3(u32 svc, u32 cmd, u32 arg1, u32 arg2, u32 arg3)
+{
+	int context_id;
+	register u32 r0 asm("r0") = SCM_ATOMIC(svc, cmd, 3);
+	register u32 r1 asm("r1") = (u32)&context_id;
+	register u32 r2 asm("r2") = arg1;
+	register u32 r3 asm("r3") = arg2;
+	register u32 r4 asm("r4") = arg3;
+
+	asm volatile(
+		__asmeq("%0", "r0")
+		__asmeq("%1", "r0")
+		__asmeq("%2", "r1")
+		__asmeq("%3", "r2")
+		__asmeq("%4", "r3")
+		__asmeq("%5", "r4")
+#ifdef REQUIRES_SEC
+			".arch_extension sec\n"
+#endif
+		"smc	#0	@ switch to secure world\n"
+		: "=r" (r0)
+		: "r" (r0), "r" (r1), "r" (r2), "r" (r3), "r" (r4));
+	return r0;
+}
+EXPORT_SYMBOL(scm_call_atomic3);
+
 s32 scm_call_atomic4_3(u32 svc, u32 cmd, u32 arg1, u32 arg2,
 		u32 arg3, u32 arg4, u32 *ret1, u32 *ret2)
 {