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Date:   Mon, 10 Jun 2013 18:17:24 +0100 (BST)
From:   "Maciej W. Rozycki" <macro@linux-mips.org>
To:     Manuel Lauss <manuel.lauss@gmail.com>
cc:     Linux-MIPS <linux-mips@linux-mips.org>,
        Ralf Baechle <ralf@linux-mips.org>
Subject: Re: [PATCH v3] MIPS: Alchemy: fix wait function
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On Sat, 8 Jun 2013, Manuel Lauss wrote:

> diff --git a/arch/mips/kernel/idle.c b/arch/mips/kernel/idle.c
> index 3b09b88..0c655de 100644
> --- a/arch/mips/kernel/idle.c
> +++ b/arch/mips/kernel/idle.c
> @@ -93,26 +93,27 @@ static void rm7k_wait_irqoff(void)
>  }
>  
>  /*
> - * The Au1xxx wait is available only if using 32khz counter or
> - * external timer source, but specifically not CP0 Counter.
> - * alchemy/common/time.c may override cpu_wait!
> + * Au1 'wait' is only useful when the 32kHz counter is used as timer,
> + * since coreclock (and the cp0 counter) stops upon executing it. Only an
> + * interrupt can wake it, so they must be enabled before entering idle modes.
>   */
>  static void au1k_wait(void)
>  {
> +	unsigned long c0status = read_c0_status() | 1;	/* irqs on */
> +
>  	__asm__(
>  	"	.set	mips3			\n"
>  	"	cache	0x14, 0(%0)		\n"
>  	"	cache	0x14, 32(%0)		\n"
>  	"	sync				\n"
> -	"	nop				\n"
> +	"	mtc0	%1, $12			\n" /* wr c0status */
>  	"	wait				\n"
>  	"	nop				\n"
>  	"	nop				\n"
>  	"	nop				\n"
>  	"	nop				\n"
>  	"	.set	mips0			\n"
> -	: : "r" (au1k_wait));
> -	local_irq_enable();
> +	: : "r" (au1k_wait), "r" (c0status));
>  }
>  
>  static int __initdata nowait;

 Not exacly what I had in mind, but this looks good to me too. :)

Acked-by: Maciej W. Rozycki <macro@linux-mips.org>

  Maciej