Subject: [PATCH 3/6] irqchip: gic: use writel instead of dsb + writel_relaxed

From: [email-masked] (Catalin Marinas)
Date: Thu, 6 Feb 2014 11:45:59 +0000

On Thu, Feb 06, 2014 at 11:30:50AM +0000, Will Deacon wrote:
> diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
> index 341c6016812d..03fe5ef3f2fe 100644
> --- a/drivers/irqchip/irq-gic.c
> +++ b/drivers/irqchip/irq-gic.c
> @@ -662,11 +662,10 @@ void gic_raise_softirq(const struct cpumask *mask, unsigned int irq)
>  	/*
>  	 * Ensure that stores to Normal memory are visible to the
>  	 * other CPUs before issuing the IPI.
> +	 *
> +	 * This always happens on GIC0.
>  	 */
> -	dsb();
> -
> -	/* this always happens on GIC0 */
> -	writel_relaxed(map << 16 | irq, gic_data_dist_base(&gic_data[0]) + GIC_DIST_SOFTINT);
> +	writel(map << 16 | irq, gic_data_dist_base(&gic_data[0]) + GIC_DIST_SOFTINT);

That's heavier than a dsb() since with outer caches on ARM we also get
an outer_sync() call.

-- 
Catalin