omap1: Fix sched_clock implementation when both MPU timer and 32K timer are used

Earlier patches select HAVE_SCHED_CLOCK for omaps. To have working sched_clock
also for MPU timer, we need to implement it in a way where the right one gets
selected during the runtime.
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/mach-omap1/time.c

@@ -219,6 +219,24 @@ static struct clocksource clocksource_mpu = {
 
 static DEFINE_CLOCK_DATA(cd);
 
+static inline unsigned long long notrace _omap_mpu_sched_clock(void)
+{
+	u32 cyc = mpu_read(&clocksource_mpu);
+	return cyc_to_sched_clock(&cd, cyc, (u32)~0);
+}
+
+#ifndef CONFIG_OMAP_32K_TIMER
+unsigned long long notrace sched_clock(void)
+{
+	return _omap_mpu_sched_clock();
+}
+#else
+static unsigned long long notrace omap_mpu_sched_clock(void)
+{
+	return _omap_mpu_sched_clock();
+}
+#endif
+
 static void notrace mpu_update_sched_clock(void)
 {
 	u32 cyc = mpu_read(&clocksource_mpu);
@@ -262,6 +280,30 @@ static inline void omap_mpu_timer_init(void)
 }
 #endif	/* CONFIG_OMAP_MPU_TIMER */
 
+#if defined(CONFIG_OMAP_MPU_TIMER) && defined(CONFIG_OMAP_32K_TIMER)
+static unsigned long long (*preferred_sched_clock)(void);
+
+unsigned long long notrace sched_clock(void)
+{
+	if (!preferred_sched_clock)
+		return 0;
+
+	return preferred_sched_clock();
+}
+
+static inline void preferred_sched_clock_init(bool use_32k_sched_clock)
+{
+	if (use_32k_sched_clock)
+		preferred_sched_clock = omap_32k_sched_clock;
+	else
+		preferred_sched_clock = omap_mpu_sched_clock;
+}
+#else
+static inline void preferred_sched_clock_init(bool use_32k_sched_clcok)
+{
+}
+#endif
+
 static inline int omap_32k_timer_usable(void)
 {
 	int res = false;
@@ -283,8 +325,12 @@ static inline int omap_32k_timer_usable(void)
  */
 static void __init omap_timer_init(void)
 {
-	if (!omap_32k_timer_usable())
+	if (omap_32k_timer_usable()) {
+		preferred_sched_clock_init(1);
+	} else {
 		omap_mpu_timer_init();
+		preferred_sched_clock_init(0);
+	}
 }
 
 struct sys_timer omap_timer = {

arch/arm/plat-omap/counter_32k.c

@@ -120,12 +120,24 @@ static DEFINE_CLOCK_DATA(cd);
 #define SC_MULT		4000000000u
 #define SC_SHIFT	17
 
-unsigned long long notrace sched_clock(void)
+static inline unsigned long long notrace _omap_32k_sched_clock(void)
 {
 	u32 cyc = clocksource_32k.read(&clocksource_32k);
 	return cyc_to_fixed_sched_clock(&cd, cyc, (u32)~0, SC_MULT, SC_SHIFT);
 }
 
+#ifndef CONFIG_OMAP_MPU_TIMER
+unsigned long long notrace sched_clock(void)
+{
+	return _omap_32k_sched_clock();
+}
+#else
+unsigned long long notrace omap_32k_sched_clock(void)
+{
+	return _omap_32k_sched_clock();
+}
+#endif
+
 static void notrace omap_update_sched_clock(void)
 {
 	u32 cyc = clocksource_32k.read(&clocksource_32k);

arch/arm/plat-omap/include/plat/common.h

@@ -37,6 +37,7 @@ extern void omap_map_common_io(void);
 extern struct sys_timer omap_timer;
 extern bool omap_32k_timer_init(void);
 extern int __init omap_init_clocksource_32k(void);
+extern unsigned long long notrace omap_32k_sched_clock(void);
 
 extern void omap_reserve(void);