OMAP: counter_32k: init clocksource as part of machine timer init

After commit dc548fb ("ARM: omap: convert
sched_clock() to use new infrastructure"), OMAPs that use the 32KiHz
"synchronization timer" as their clocksource crash during boot:

[    0.000000] OMAP clockevent source: GPTIMER1 at 32768 Hz
[    0.000000] Unable to handle kernel NULL pointer dereference at virtual address 00000000
[    0.000000] pgd = c0004000
[    0.000000] [00000000] *pgd=00000000
[    0.000000] Internal error: Oops: 80000005 [#1] SMP
[    0.000000] last sysfs file:
[    0.000000] Modules linked in:
[    0.000000] CPU: 0    Tainted: G        W    (2.6.37-07734-g2467802 #7)
[    0.000000] PC is at 0x0
[    0.000000] LR is at sched_clock_poll+0x2c/0x3c
[    0.000000] pc : [<00000000>]    lr : [<c0060b74>]    psr: 600001d3
[    0.000000] sp : c058bfd0  ip : c058a000  fp : 00000000
[    0.000000] r10: 00000000  r9 : 411fc092  r8 : 800330c8
[    0.000000] r7 : c05a08e0  r6 : c0034c48  r5 : c05ffc40  r4 : c0034c4c
[    0.000000] r3 : c05ffe6c  r2 : c05a0bc0  r1 : c059f098  r0 : 00000000
[    0.000000] Flags: nZCv  IRQs off  FIQs off  Mode SVC_32  ISA ARM  Segment kernel
[    0.000000] Control: 10c53c7f  Table: 8000404a  DAC: 00000017

This is due to the recent ARM init_sched_clock() changes and the late
initialization of the counter_32k clock source.  More information here:

   http://marc.info/?l=linux-omap&m=129513468605208&w=2

Fix by initializing the counter_32k clocksource during the machine timer
initialization.

Reported-by: Russell King <rmk+kernel@arm.linux.org.uk>
Tested-by: Thomas Weber <weber@corscience.de>
Signed-off-by: Paul Walmsley <paul@pwsan.com>

arch/arm/mach-omap1/time.c

@@ -244,6 +244,13 @@ static void __init omap_timer_init(void)
 
 	omap_init_mpu_timer(rate);
 	omap_init_clocksource(rate);
+	/*
+	 * XXX Since this file seems to deal mostly with the MPU timer,
+	 * this doesn't seem like the correct place for the sync timer
+	 * clocksource init.
+	 */
+	if (!cpu_is_omap7xx() && !cpu_is_omap15xx())
+		omap_init_clocksource_32k();
 }
 
 struct sys_timer omap_timer = {

arch/arm/mach-omap2/timer-gp.c

@@ -42,6 +42,8 @@
 
 #include "timer-gp.h"
 
+#include <plat/common.h>
+
 /* MAX_GPTIMER_ID: number of GPTIMERs on the chip */
 #define MAX_GPTIMER_ID		12
 
@@ -176,10 +178,14 @@ static void __init omap2_gp_clockevent_init(void)
 /* 
  * When 32k-timer is enabled, don't use GPTimer for clocksource
  * instead, just leave default clocksource which uses the 32k
- * sync counter.  See clocksource setup in see plat-omap/common.c. 
+ * sync counter.  See clocksource setup in plat-omap/counter_32k.c
  */
 
-static inline void __init omap2_gp_clocksource_init(void) {}
+static void __init omap2_gp_clocksource_init(void)
+{
+	omap_init_clocksource_32k();
+}
+
 #else
 /*
  * clocksource

arch/arm/plat-omap/counter_32k.c

@@ -160,7 +160,7 @@ void read_persistent_clock(struct timespec *ts)
 	*ts = *tsp;
 }
 
-static int __init omap_init_clocksource_32k(void)
+int __init omap_init_clocksource_32k(void)
 {
 	static char err[] __initdata = KERN_ERR
 			"%s: can't register clocksource!\n";
@@ -195,7 +195,6 @@ static int __init omap_init_clocksource_32k(void)
 	}
 	return 0;
 }
-arch_initcall(omap_init_clocksource_32k);
 
 #endif	/* !(defined(CONFIG_ARCH_OMAP730) || defined(CONFIG_ARCH_OMAP15XX)) */
 

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

@@ -35,6 +35,7 @@ struct sys_timer;
 
 extern void omap_map_common_io(void);
 extern struct sys_timer omap_timer;
+extern int __init omap_init_clocksource_32k(void);
 
 extern void omap_reserve(void);