Re: [Xenomai] [PATCH] AT91: SAMA5D3: Adapt Ipipe for AIC5

[Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>]

On 07/01/2014 12:27 PM, Maxime Ripard wrote:
> -
> -	at91_pic_muter_register();
>  }

Obviously, some if (soc_is_foo()) missing here.

> +static void __maybe_unused at91_aic5_eoi(struct irq_data *d)
> +{
> +	at91_aic_write(AT91_AIC5_EOICR, 0);
> +}

You want to make that inline, so that the hold callback ends-up doing
just two register writes without any function calls, improving interrupt
latency.

> +
>  #ifdef CONFIG_IPIPE
>  static void at91_aic_hold_irq(struct irq_data *d)
>  {
> @@ -258,13 +283,20 @@ static void at91_aic_release_irq(struct irq_data *d)
>  {
>  	at91_aic_hard_unmask_irq(d);
>  }
> -#endif /* CONFIG_IPIPE */
>  
> -static void __maybe_unused at91_aic5_eoi(struct irq_data *d)
> +static void at91_aic5_hold_irq(struct irq_data *d)
>  {
> -	at91_aic_write(AT91_AIC5_EOICR, 0);
> +	at91_aic5_hard_mask_irq(d);
> +	at91_aic5_eoi(d);
>  }
>  
> +static void at91_aic5_release_irq(struct irq_data *d)
> +{
> +	at91_aic5_hard_unmask_irq(d);
> +}

The ->release callback is called with irqs on, so you may want to call
hard_local_irq_save / hard_local_irq_restore to make it atomic (note
that the old at91s are also broken by the addition of the call to
set_backup). Alternatively, you may move the clear_backup/set_bakcup
calls to the linux mask/unmask routines, so that the register writes
remain atomic, and you can avoid the save/restore and function calls and
improve the interrupt latency.


-- 
                                                                Gilles.