linux-kernel - Re: [PATCH V2 14/63] clocksource/drivers/bcm_kona: Convert init function to return error

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Date:	Mon, 20 Jun 2016 10:22:08 -0700
From:	Ray Jui <ray.jui@...adcom.com>
To:	Daniel Lezcano <daniel.lezcano@...aro.org>, tglx@...utronix.de
Cc:	linux-kernel@...r.kernel.org,
	Florian Fainelli <f.fainelli@...il.com>,
	Ray Jui <rjui@...adcom.com>,
	Scott Branden <sbranden@...adcom.com>,
	"open list:BROADCOM BCM281XX..." 
	<bcm-kernel-feedback-list@...adcom.com>
Subject: Re: [PATCH V2 14/63] clocksource/drivers/bcm_kona: Convert init
 function to return error

Hi Daniel,

On 6/16/2016 2:26 PM, Daniel Lezcano wrote:
> The init functions do not return any error. They behave as the following:
>
>   - panic, thus leading to a kernel crash while another timer may work and
>        make the system boot up correctly
>
>   or
>
>   - print an error and let the caller unaware if the state of the system
>
> Change that by converting the init functions to return an error conforming
> to the CLOCKSOURCE_OF_RET prototype.
>
> Proper error handling (rollback, errno value) will be changed later case
> by case, thus this change just return back an error or success in the init
> function.
>
> Signed-off-by: Daniel Lezcano <daniel.lezcano@...aro.org>
> ---
>  drivers/clocksource/bcm_kona_timer.c | 12 +++++++-----
>  1 file changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/clocksource/bcm_kona_timer.c b/drivers/clocksource/bcm_kona_timer.c
> index e717e87..98bc2a2 100644
> --- a/drivers/clocksource/bcm_kona_timer.c
> +++ b/drivers/clocksource/bcm_kona_timer.c
> @@ -163,14 +163,14 @@ static struct irqaction kona_timer_irq = {
>  	.handler = kona_timer_interrupt,
>  };
>
> -static void __init kona_timer_init(struct device_node *node)
> +static int __init kona_timer_init(struct device_node *node)
>  {
>  	u32 freq;
>  	struct clk *external_clk;
>
>  	if (!of_device_is_available(node)) {
>  		pr_info("Kona Timer v1 marked as disabled in device tree\n");
> -		return;
> +		return 0;

I thought we should return -ENODEV here.

Moreover, if this device node is not enabled, kona_timer_init won't even 
be invoked. Can we simply get rid of this check here?

>  	}
>
>  	external_clk = of_clk_get_by_name(node, NULL);
> @@ -182,7 +182,7 @@ static void __init kona_timer_init(struct device_node *node)
>  		arch_timer_rate = freq;
>  	} else {
>  		pr_err("Kona Timer v1 unable to determine clock-frequency");
> -		return;
> +		return -EINVAL;
>  	}
>
>  	/* Setup IRQ numbers */
> @@ -196,11 +196,13 @@ static void __init kona_timer_init(struct device_node *node)
>  	kona_timer_clockevents_init();
>  	setup_irq(timers.tmr_irq, &kona_timer_irq);
>  	kona_timer_set_next_event((arch_timer_rate / HZ), NULL);
> +
> +	return 0;
>  }
>
> -CLOCKSOURCE_OF_DECLARE(brcm_kona, "brcm,kona-timer", kona_timer_init);
> +CLOCKSOURCE_OF_DECLARE_RET(brcm_kona, "brcm,kona-timer", kona_timer_init);
>  /*
>   * bcm,kona-timer is deprecated by brcm,kona-timer
>   * being kept here for driver compatibility
>   */
> -CLOCKSOURCE_OF_DECLARE(bcm_kona, "bcm,kona-timer", kona_timer_init);
> +CLOCKSOURCE_OF_DECLARE_RET(bcm_kona, "bcm,kona-timer", kona_timer_init);
>

Thanks,

Ray