[PATCH] arch_timer: Do not register arch_sys_counter twice

[Will Deacon]

On Tue, Oct 15, 2013 at 02:31:51PM +0100, Thierry Reding wrote:
> Commit 65cd4f6 (arch_timer: Move to generic sched_clock framework) added
> code to register the arch_sys_counter in arch_timer_register() but it is
> already registered in arch_counter_register(). This results in the timer
> being added to the clocksource list twice, therefore causing an infinite
> loop in the list.
> 
> Remove the duplicate registration and register the scheduler clock after
> the original registration instead.
> 
> This fixes a hang during boot on Tegra114 (Cortex-A15).
> 
> Signed-off-by: Thierry Reding <treding at nvidia.com>
> ---
> While I've only tested this on Tegra114, I suspect the same hang during
> boot happens for all processors that use this clock source.
> 
>  drivers/clocksource/arm_arch_timer.c | 12 +++---------
>  1 file changed, 3 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
> index f655036..95fb944 100644
> --- a/drivers/clocksource/arm_arch_timer.c
> +++ b/drivers/clocksource/arm_arch_timer.c
> @@ -436,6 +436,9 @@ 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)
> @@ -515,15 +518,6 @@ 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,

Excuse my ignorance, but I'm failing to apply either this patch or the one
that Stephen Boyd proposed:

  http://lists.infradead.org/pipermail/linux-arm-kernel/2013-October/204665.html

The second hunk (deletions) doesn't apply at all, and if I just apply the
first hunk then things won't compile. Which tree is this against?

Will