Subject: [PATCH 06/10] arm: arch_timer: divorce from local_timer api

From: [email-masked] (Stephen Boyd)
Date: Fri, 07 Dec 2012 14:16:42 -0800

On 11/30/12 09:46, Mark Rutland wrote:
> Currently, the arch_timer driver is tied to the arm port, as it relies
> on code in arch/arm/smp.c to setup and teardown timers as cores are
> hotplugged on and off. The timer is registered through an arm-specific
> registration mechanism, preventing sharing the driver with the arm64
> port.
>
> This patch moves the driver to using a cpu notifier instead, making it
> easier to port.

How does ipi_timer() work after this change? Don't we need it because of
FEAT_C3_STOP?

>
> Signed-off-by: Mark Rutland <[email-masked]>
> Acked-by: Catalin Marinas <[email-masked]>
> Acked-by: Marc Zyngier <[email-masked]>
> ---
[snip]
> @@ -245,12 +244,28 @@ static void __cpuinit arch_timer_stop(struct clock_event_device *clk)
>  	clk->set_mode(CLOCK_EVT_MODE_UNUSED, clk);
>  }
>  
> -static struct local_timer_ops arch_timer_ops __cpuinitdata = {
> -	.setup	= arch_timer_setup,
> -	.stop	= arch_timer_stop,
> -};
> +static int __cpuinit arch_timer_cpu_notify(struct notifier_block *self,
> +					   unsigned long action, void *hcpu)
> +{
> +	struct clock_event_device *evt = this_cpu_ptr(arch_timer_evt);
> +
> +	switch (action) {
> +	case CPU_STARTING:
> +	case CPU_STARTING_FROZEN:
> +		arch_timer_setup(evt);
> +		break;
> +	case CPU_DYING:
> +	case CPU_DYING_FROZEN:
> +		arch_timer_stop(evt);
> +		break;
> +	}

You can save 2 lines with a switch (action & ~CPU_TASKS_FROZEN) here.

> +
> +	return NOTIFY_OK;
> +}
>  
> -static struct clock_event_device arch_timer_global_evt;
> +static struct notifier_block __cpuinitdata arch_timer_cpu_nb = {

__cpuinitdata goes last before the equals sign.

> +	.notifier_call = arch_timer_cpu_notify,
> +};
>  
>  static int __init arch_timer_register(void)
>  {
>

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