msm: scm: Add atomic SCM APIs
The atomic SCM APIs are useful for commands that are guaranteed
by the secure side to be uninterruptable, atomic and SMP safe.
The calling convention use registers for passing parameters and
return values between the secure and non-secure side. Support
this interface with scm_call_atomic[1-2]() functions
corresponding to the number of arguments passed.
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 737ba76..48df22e 100644
--- a/arch/arm/mach-msm/scm.c
+++ b/arch/arm/mach-msm/scm.c
@@ -266,6 +266,73 @@
}
EXPORT_SYMBOL(scm_call);
+#define SCM_CLASS_REGISTER (0x2 << 8)
+#define SCM_MASK_IRQS BIT(5)
+#define SCM_ATOMIC(svc, cmd, n) (((((svc) << 10)|((cmd) & 0x3ff)) << 12) | \
+ SCM_CLASS_REGISTER | \
+ SCM_MASK_IRQS | \
+ (n & 0xf))
+
+/**
+ * scm_call_atomic1() - Send an atomic SCM command with one argument
+ * @svc_id: service identifier
+ * @cmd_id: command identifier
+ * @arg1: first argument
+ *
+ * This shall only be used with commands that are guaranteed to be
+ * uninterruptable, atomic and SMP safe.
+ */
+u32 scm_call_atomic1(u32 svc, u32 cmd, u32 arg1)
+{
+ int context_id;
+ register u32 r0 asm("r0") = SCM_ATOMIC(svc, cmd, 1);
+ register u32 r1 asm("r1") = (u32)&context_id;
+ register u32 r2 asm("r2") = arg1;
+
+ asm volatile(
+ __asmeq("%0", "r0")
+ __asmeq("%1", "r0")
+ __asmeq("%2", "r1")
+ __asmeq("%3", "r2")
+ "smc #0 @ switch to secure world\n"
+ : "=r" (r0)
+ : "r" (r0), "r" (r1), "r" (r2)
+ : "r3");
+ return r0;
+}
+EXPORT_SYMBOL(scm_call_atomic1);
+
+/**
+ * scm_call_atomic2() - Send an atomic SCM command with two arguments
+ * @svc_id: service identifier
+ * @cmd_id: command identifier
+ * @arg1: first argument
+ * @arg2: second argument
+ *
+ * This shall only be used with commands that are guaranteed to be
+ * uninterruptable, atomic and SMP safe.
+ */
+u32 scm_call_atomic2(u32 svc, u32 cmd, u32 arg1, u32 arg2)
+{
+ int context_id;
+ register u32 r0 asm("r0") = SCM_ATOMIC(svc, cmd, 2);
+ register u32 r1 asm("r1") = (u32)&context_id;
+ register u32 r2 asm("r2") = arg1;
+ register u32 r3 asm("r3") = arg2;
+
+ asm volatile(
+ __asmeq("%0", "r0")
+ __asmeq("%1", "r0")
+ __asmeq("%2", "r1")
+ __asmeq("%3", "r2")
+ __asmeq("%4", "r3")
+ "smc #0 @ switch to secure world\n"
+ : "=r" (r0)
+ : "r" (r0), "r" (r1), "r" (r2), "r" (r3));
+ return r0;
+}
+EXPORT_SYMBOL(scm_call_atomic2);
+
u32 scm_get_version(void)
{
int context_id;