1 files changed, 31 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
index d9a9974c6938..c434823b8c83 100644
--- a/arch/powerpc/kernel/rtas.c
+++ b/arch/powerpc/kernel/rtas.c
@@ -38,6 +38,7 @@
 #include <asm/syscalls.h>
 #include <asm/smp.h>
 #include <asm/atomic.h>
+#include <asm/time.h>
 
 struct rtas_t rtas = {
         .lock = __RAW_SPIN_LOCK_UNLOCKED
@@ -971,3 +972,33 @@ int __init early_init_dt_scan_rtas(unsigned long node,
         /* break now */
         return 1;
 }
+
+static raw_spinlock_t timebase_lock;
+static u64 timebase = 0;
+
+void __cpuinit rtas_give_timebase(void)
+{
+        unsigned long flags;
+
+        local_irq_save(flags);
+        hard_irq_disable();
+        __raw_spin_lock(&timebase_lock);
+        rtas_call(rtas_token("freeze-time-base"), 0, 1, NULL);
+        timebase = get_tb();
+        __raw_spin_unlock(&timebase_lock);
+
+        while (timebase)
+                barrier();
+        rtas_call(rtas_token("thaw-time-base"), 0, 1, NULL);
+        local_irq_restore(flags);
+}
+
+void __cpuinit rtas_take_timebase(void)
+{
+        while (!timebase)
+                barrier();
+        __raw_spin_lock(&timebase_lock);
+        set_tb(timebase >> 32, timebase & 0xffffffff);
+        timebase = 0;
+        __raw_spin_unlock(&timebase_lock);
+}