add ARM architecture-dependent files

The atomic.h file is currently only a dummy, but it is sufficient to
get basic real-time tasks to run.

2 files changed, 32 insertions, 0 deletions

diff --git a/arch/arm/include/asm/atomic.h b/arch/arm/include/asm/atomic.h
new file mode 100644
index 0000000..70dbf80
--- /dev/null
+++ b/arch/arm/include/asm/atomic.h
@@ -0,0 +1,9 @@
+#ifndef ASM_ATOMIC_H
+#define ASM_ATOMIC_H
+
+static inline void barrier(void)
+{
+        /* not yet implemented */
+}
+
+#endif
diff --git a/arch/arm/include/asm/cycles.h b/arch/arm/include/asm/cycles.h
new file mode 100644
index 0000000..73632f8
--- /dev/null
+++ b/arch/arm/include/asm/cycles.h
@@ -0,0 +1,23 @@
+#ifndef ASM_CYCLES_H
+#define ASM_CYCLES_H
+
+typedef unsigned long cycles_t;
+
+#define CYCLES_FMT "lu"
+
+/* system call wrapper */
+int null_call(cycles_t *timestamp);
+
+static inline cycles_t get_cycles(void)
+{
+        cycles_t c;
+        /* On the ARM11 MPCore chips, userspace cannot access the cycle counter
+         * directly. So ask the kernel to read it instead. Eventually, this
+         * should support newer ARM chips that do allow accessing the cycle
+         * counter in userspace.
+         */
+        null_call(&c);
+        return c;
+}
+
+#endif