[PATCH] omap1: Fix sched_clock implementation when both MPU timer and 32K timer are used (Re: State of LDP3430 platform)

Tony Lindgren
2011-01-19T18:43:37Z

* Tony Lindgren <tony@atomide.com> [110118 15:20]:
> * Tony Lindgren <tony@atomide.com> [110118 14:34]:
> > For omap15xx and 730 we need to use the MPU timer
> > as the 32K timer is not available. For omap16xx
> > we want to use the 32K timer because of PM. Fix this
> > by allowing to build in both timers.
>
> This still needs one more patch to deal with the
> sched_clock for MPU timer..

And here's that patch to make sched_clock work with both
timers.

Tony

From: Tony Lindgren <tony@atomide.com>
Date: Tue, 18 Jan 2011 17:00:00 -0800
Subject: [PATCH] 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>

--- a/arch/arm/mach-omap1/time.c
+++ b/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 = {
--- a/arch/arm/plat-omap/counter_32k.c
+++ b/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);
--- a/arch/arm/plat-omap/include/plat/common.h
+++ b/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);