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SubjectRe: [PATCH v4 05/17] arch_timer: Move to generic sched_clock framework
On 10/14/13 11:44, Kevin Hilman wrote:
> Stephen Boyd <sboyd@codeaurora.org> writes:
>
>> Register with the generic sched_clock framework now that it
>> supports 64 bits. This fixes two problems with the current
>> sched_clock support for machines using the architected timers.
>> First off, we don't subtract the start value from subsequent
>> sched_clock calls so we can potentially start off with
>> sched_clock returning gigantic numbers. Second, there is no
>> support for suspend/resume handling so problems such as discussed
>> in 6a4dae5 (ARM: 7565/1: sched: stop sched_clock() during
>> suspend, 2012-10-23) can happen without this patch. Finally, it
>> allows us to move the sched_clock setup into drivers clocksource
>> out of the arch ports.
>>
>> Cc: Christopher Covington <cov@codeaurora.org>
>> Cc: Catalin Marinas <catalin.marinas@arm.com>
>> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
> A boot failure on Exynos5/Arndale showed up in next-20131014[1], and a
> subsequent bisect has fingered this patch as the culprit.
>
> I haven't had a chance to debug this any further, but wanted to share in
> case someone else can debug.
>
> The console log is below, but don't think there is much useful there as
> it shows nothing after the 'Starting kernel ...' from u-boot.

debug_ll output would be nice. Anyway, that patch looks "weird". It is
definitely not what I sent out. Most notably, this hunk jumps out

@@ -471,6 +472,15 @@ static int __init arch_timer_register(void)
goto out;
}

+ clocksource_register_hz(&clocksource_counter, arch_timer_rate);
+ cyclecounter.mult = clocksource_counter.mult;
+ cyclecounter.shift = clocksource_counter.shift;
+ timecounter_init(&timecounter, &cyclecounter,
+ arch_counter_get_cntvct());
+
+ /* 56 bits minimum, so we assume worst case rollover */
+ sched_clock_register(arch_timer_read_counter, 56, arch_timer_rate);
+
if (arch_timer_use_virtual) {
ppi = arch_timer_ppi[VIRT_PPI];
err = request_percpu_irq(ppi, arch_timer_handler_virt,


Which is adding the clocksource_register_hz() and timecounter_init()
call twice. It should only be adding the sched_clock_register() call and
the sched_clock_register() call should be in arch_counter_register().
Can you try this patch?

----8<----

diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index 5d52789..865ecd8 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -420,6 +420,9 @@ static void __init arch_counter_register(unsigned type)
cyclecounter.mult = clocksource_counter.mult;
cyclecounter.shift = clocksource_counter.shift;
timecounter_init(&timecounter, &cyclecounter, start_count);
+
+ /* 56 bits minimum, so we assume worst case rollover */
+ sched_clock_register(arch_timer_read_counter, 56, arch_timer_rate);
}

static void arch_timer_stop(struct clock_event_device *clk)
@@ -472,15 +475,6 @@ static int __init arch_timer_register(void)
goto out;
}

- clocksource_register_hz(&clocksource_counter, arch_timer_rate);
- cyclecounter.mult = clocksource_counter.mult;
- cyclecounter.shift = clocksource_counter.shift;
- timecounter_init(&timecounter, &cyclecounter,
- arch_counter_get_cntvct());
-
- /* 56 bits minimum, so we assume worst case rollover */
- sched_clock_register(arch_timer_read_counter, 56, arch_timer_rate);
-
if (arch_timer_use_virtual) {
ppi = arch_timer_ppi[VIRT_PPI];
err = request_percpu_irq(ppi, arch_timer_handler_virt,
--
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