From d8328f3b85f34c0dc5866f10bf6e7842fb511d62 Mon Sep 17 00:00:00 2001 From: Paul Walmsley Date: Sat, 15 Jan 2011 21:32:01 -0700 Subject: OMAP: counter_32k: init clocksource as part of machine timer init After commit dc548fbbd2ecd0fc3b02301d551e5f8e19ae58fd ("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 : [] 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 Tested-by: Thomas Weber Signed-off-by: Paul Walmsley --- arch/arm/mach-omap2/timer-gp.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) (limited to 'arch/arm/mach-omap2/timer-gp.c') diff --git a/arch/arm/mach-omap2/timer-gp.c b/arch/arm/mach-omap2/timer-gp.c index 4e48e786bec7..7b7c2683ae7b 100644 --- a/arch/arm/mach-omap2/timer-gp.c +++ b/arch/arm/mach-omap2/timer-gp.c @@ -42,6 +42,8 @@ #include "timer-gp.h" +#include + /* 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 -- cgit v1.2.3 From cbc9438075ca9dee3f39a2e7310f81c304b40359 Mon Sep 17 00:00:00 2001 From: Paul Walmsley Date: Tue, 22 Feb 2011 19:59:49 -0700 Subject: 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 Signed-off-by: Tony Lindgren --- arch/arm/mach-omap2/timer-gp.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'arch/arm/mach-omap2/timer-gp.c') 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 #include #include +#include #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); } -- cgit v1.2.3