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Commit d8328f3b authored by Paul Walmsley's avatar Paul Walmsley
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OMAP: counter_32k: init clocksource as part of machine timer init 

After commit dc548fbb ("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: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
Tested-by: default avatarThomas Weber <weber@corscience.de>
Signed-off-by: default avatarPaul Walmsley <paul@pwsan.com>
parent e78bf5e6

arch/arm/mach-omap1/time.c

+7 −0
Original line number Diff line number Diff line
@@ -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

+8 −2
Original line number Diff line number Diff line
@@ -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

+1 −2
Original line number Diff line number Diff line
@@ -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

+1 −0
Original line number Diff line number Diff line
@@ -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);