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| author | Paul Walmsley <paul@pwsan.com> | 2011-02-22 19:59:49 -0700 |
|---|---|---|
| committer | Tony Lindgren <tony@atomide.com> | 2011-02-24 12:21:21 -0800 |
| commit | cbc9438075ca9dee3f39a2e7310f81c304b40359 (patch) | |
| tree | eac5f9ed25b96e64a664f5af441e0c238e44cd18 /arch | |
| parent | c03773206bf2249a890c4d420ed32ef500630095 (diff) | |
| download | linux-cbc9438075ca9dee3f39a2e7310f81c304b40359.tar.gz linux-cbc9438075ca9dee3f39a2e7310f81c304b40359.tar.bz2 linux-cbc9438075ca9dee3f39a2e7310f81c304b40359.zip | |
OMAP2+: clocksource: fix crash on boot when !CONFIG_OMAP_32K_TIMER
OMAP2+ kernels built without CONFIG_OMAP_32K_TIMER crash on boot after the
2.6.38 sched_clock changes:
[ 0.000000] OMAP clockevent source: GPTIMER1 at 13000000 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 Not tainted (2.6.38-rc5-00057-g04aa67d #152)
[ 0.000000] PC is at 0x0
[ 0.000000] LR is at sched_clock_poll+0x2c/0x3c
Without CONFIG_OMAP_32K_TIMER, the kernel has an clockevent and
clocksource resolution about three orders of magnitude higher than
with CONFIG_OMAP_32K_TIMER set. The tradeoff is that the lowest
power consumption states are not available.
Fix by calling init_sched_clock() from the GPTIMER clocksource init code.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm/mach-omap2/timer-gp.c | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/arch/arm/mach-omap2/timer-gp.c b/arch/arm/mach-omap2/timer-gp.c index 7b7c2683ae7b..0fc550e7e482 100644 --- a/arch/arm/mach-omap2/timer-gp.c +++ b/arch/arm/mach-omap2/timer-gp.c @@ -39,6 +39,7 @@ #include <asm/mach/time.h> #include <plat/dmtimer.h> #include <asm/localtimer.h> +#include <asm/sched_clock.h> #include "timer-gp.h" @@ -190,6 +191,7 @@ static void __init omap2_gp_clocksource_init(void) /* * clocksource */ +static DEFINE_CLOCK_DATA(cd); static struct omap_dm_timer *gpt_clocksource; static cycle_t clocksource_read_cycles(struct clocksource *cs) { @@ -204,6 +206,15 @@ static struct clocksource clocksource_gpt = { .flags = CLOCK_SOURCE_IS_CONTINUOUS, }; +static void notrace dmtimer_update_sched_clock(void) +{ + u32 cyc; + + cyc = omap_dm_timer_read_counter(gpt_clocksource); + + update_sched_clock(&cd, cyc, (u32)~0); +} + /* Setup free-running counter for clocksource */ static void __init omap2_gp_clocksource_init(void) { @@ -224,6 +235,8 @@ static void __init omap2_gp_clocksource_init(void) omap_dm_timer_set_load_start(gpt, 1, 0); + init_sched_clock(&cd, dmtimer_update_sched_clock, 32, tick_rate); + if (clocksource_register_hz(&clocksource_gpt, tick_rate)) printk(err2, clocksource_gpt.name); } |