ARM: provide get_cycles() for RealView PB11{MP,76} and Cortex-A8

Use the CCNT register to override the default get_cycles() implementation in
arch/arm/asm/timex.h. This is useful for overhead measurements and debugging.

1 files changed, 27 insertions, 0 deletions

diff --git a/arch/arm/mach-realview/include/mach/timex.h b/arch/arm/mach-realview/include/mach/timex.h
index 4eeb069373c2..e8bcc40d1f08 100644
--- a/arch/arm/mach-realview/include/mach/timex.h
+++ b/arch/arm/mach-realview/include/mach/timex.h
@@ -21,3 +21,30 @@
  */
 
 #define CLOCK_TICK_RATE         (50000000 / 16)
+
+#if defined(CONFIG_MACH_REALVIEW_PB11MP) || defined(CONFIG_MACH_REALVIEW_PB1176)
+
+static inline unsigned long realview_get_arm11_cp15_ccnt(void)
+{
+        unsigned long cycles;
+        /* Read CP15 CCNT register. */
+        asm volatile ("mrc p15, 0, %0, c15, c12, 1" : "=r" (cycles));
+        return cycles;
+}
+
+#define get_cycles realview_get_arm11_cp15_ccnt
+
+#elif defined(CONFIG_MACH_REALVIEW_PBA8)
+
+
+static inline unsigned long realview_get_a8_cp15_ccnt(void)
+{
+        unsigned long cycles;
+        /* Read CP15 CCNT register. */
+        asm volatile ("mrc p15, 0, %0, c9, c13, 0" : "=r" (cycles));
+        return cycles;
+}
+
+#define get_cycles realview_get_a8_cp15_ccnt
+
+#endif