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From: Sergei Shtylyov <sshtylyov@mvista.com>
To: Manuel Lauss <manuel.lauss@googlemail.com>
Cc: Linux-MIPS <linux-mips@linux-mips.org>
Subject: Re: [PATCH] MIPS: DB1200: Set Config_OD for improved stability.
Date: Thu, 10 Feb 2011 21:14:53 +0300	[thread overview]
Message-ID: <4D542B1D.1060407@mvista.com> (raw)
In-Reply-To: <1297347429-18215-2-git-send-email-manuel.lauss@googlemail.com>

Hello.

Manuel Lauss wrote:

> Setting Config_OD gets rid of a _LOT_ of spurious CPLD interrupts,
> but also decreases overall performance a bit.

> Signed-off-by: Manuel Lauss <manuel.lauss@googlemail.com>
[...]

> diff --git a/arch/mips/alchemy/devboards/db1200/setup.c b/arch/mips/alchemy/devboards/db1200/setup.c
> index 8876195..a3729c9 100644
> --- a/arch/mips/alchemy/devboards/db1200/setup.c
> +++ b/arch/mips/alchemy/devboards/db1200/setup.c
> @@ -23,6 +23,13 @@ void __init board_setup(void)
>  	unsigned long freq0, clksrc, div, pfc;
>  	unsigned short whoami;
>  
> +	/* Set Config_OD (disable overlapping bus transaction):

    The bit is called Config[OD] by other Alchemy code.
    You just should add your Au1200 revision to au1xxx_cpu_needs_config_od() in 
<asm/mach-au1x00.h> so that plat_mem_setup() automatically sets the bit (just 
after it calls board_setup()); Au1200 rev. AC should have it set already...

> +	 * This gets rid of a _lot_ of spurious interrupts (especially
> +	 * wrt. IDE); but incurs ~10% performance hit in some
> +	 * cpu-bound applications.
> +	 */
> +	set_c0_config(1 << 19);
> +
>  	bcsr_init(DB1200_BCSR_PHYS_ADDR,
>  		  DB1200_BCSR_PHYS_ADDR + DB1200_BCSR_HEXLED_OFS);
>  

WBR, Sergei

  reply	other threads:[~2011-02-10 18:16 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-02-10 14:17 [PATCH RESEND] MIPS: Alchemy: update inlinable GPIO API Manuel Lauss
2011-02-10 14:17 ` [PATCH] MIPS: DB1200: Set Config_OD for improved stability Manuel Lauss
2011-02-10 18:14   ` Sergei Shtylyov [this message]
2011-02-10 18:25     ` Sergei Shtylyov
2011-02-10 14:17 ` [PATCH] Alchemy: irq: replace au_readl/writel accessors Manuel Lauss

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