ARM: 5869/1: ixp4xx: implement sched_clock()

Add a better sched_clock() to the ixp4xx platform,
implemented via its clocksource support.

This is based on the sched_clock() I implemented for
the IOP platform. Tested on a ds101 ixp420 machine.
Signed-off-by: NMikael Pettersson <mikpe@it.uu.se>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mach-ixp4xx/common.c

@@ -426,6 +426,17 @@ static void __init ixp4xx_clocksource_init(void)
 	clocksource_register(&clocksource_ixp4xx);
 }
 
+/*
+ * sched_clock()
+ */
+unsigned long long sched_clock(void)
+{
+	cycle_t cyc = ixp4xx_get_cycles(NULL);
+	struct clocksource *cs = &clocksource_ixp4xx;
+
+	return clocksource_cyc2ns(cyc, cs->mult, cs->shift);
+}
+
 /*
  * clockevents
  */