Subject: [PATCH v2] clocksource: arm_arch_timer: discard unavailable timers correctly

From: [email-masked] (Sudeep Holla)
Date: Wed, 24 Sep 2014 16:16:47 +0100

Hi Mark,

On 17/09/14 20:39, Sudeep Holla wrote:
> Currently we wait until both cp15 and mem timers are probed if we
> have both timer device nodes present in the device tree without
> checking if the device is actually available. If one of the timer
> device node present is disabled, the system locks up on the boot
> as no timer gets registered.
>
> This patch adds the check for the availablity of the timer device
> so that we unavailable timers are discarded correctly. It also adds
> the missing of_node_put.
>
> Cc: Stephen Boyd <[email-masked]>
> Cc: Mark Rutland <[email-masked]>

If your are fine with this, can I ask Daniel you pick this up ?

Regards,
Sudeep

> Signed-off-by: Sudeep Holla <[email-masked]>
> ---
>   drivers/clocksource/arm_arch_timer.c | 20 ++++++++++++++++----
>   1 file changed, 16 insertions(+), 4 deletions(-)
>
> Changes v1->v2:
> 	- Added missing of_node_put in the original code
> 	- Updated the commit log as suggested
>
> diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
> index 5163ec13429d..7e267e3990ab 100644
> --- a/drivers/clocksource/arm_arch_timer.c
> +++ b/drivers/clocksource/arm_arch_timer.c
> @@ -616,17 +616,29 @@ static const struct of_device_id arch_timer_mem_of_match[] __initconst = {
>   	{},
>   };
>
> +static bool __init
> +arch_timer_probed(int type, const struct of_device_id *matches)
> +{
> +	struct device_node *dn;
> +	bool probed = false;
> +
> +	dn = of_find_matching_node(NULL, matches);
> +	if (dn && of_device_is_available(dn) && (arch_timers_present & type))
> +		probed = true;
> +	of_node_put(dn);
> +
> +	return probed;
> +}
> +
>   static void __init arch_timer_common_init(void)
>   {
>   	unsigned mask = ARCH_CP15_TIMER | ARCH_MEM_TIMER;
>
>   	/* Wait until both nodes are probed if we have two timers */
>   	if ((arch_timers_present & mask) != mask) {
> -		if (of_find_matching_node(NULL, arch_timer_mem_of_match) &&
> -				!(arch_timers_present & ARCH_MEM_TIMER))
> +		if (!arch_timer_probed(ARCH_MEM_TIMER, arch_timer_mem_of_match))
>   			return;
> -		if (of_find_matching_node(NULL, arch_timer_of_match) &&
> -				!(arch_timers_present & ARCH_CP15_TIMER))
> +		if (!arch_timer_probed(ARCH_CP15_TIMER, arch_timer_of_match))
>   			return;
>   	}
>
>