From mboxrd@z Thu Jan  1 00:00:00 1970
From: arnd@arndb.de (Arnd Bergmann)
Date: Sat, 15 Feb 2014 14:18:08 +0100
Subject: [PATCH v2 05/23] ARM: Kirkwood: Seperate board-dt from common and
 pcie code.
In-Reply-To: <1392459621-24003-6-git-send-email-andrew@lunn.ch>
References: <1392459621-24003-1-git-send-email-andrew@lunn.ch>
 <1392459621-24003-6-git-send-email-andrew@lunn.ch>
Message-ID: <3017687.o0PD1Sf7lM@wuerfel>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Saturday 15 February 2014 11:20:03 Andrew Lunn wrote:
> +static void __init kirkwood_l2_init(void)
> +{
> +#ifdef CONFIG_CACHE_FEROCEON_L2
> +#ifdef CONFIG_CACHE_FEROCEON_L2_WRITETHROUGH
> +       writel(readl(L2_CONFIG_REG) | L2_WRITETHROUGH, L2_CONFIG_REG);
> +       feroceon_l2_init(1);
> +#else
> +       writel(readl(L2_CONFIG_REG) & ~L2_WRITETHROUGH, L2_CONFIG_REG);
> +       feroceon_l2_init(0);
> +#endif
> +#endif
> +}

I assume this is correct, but I don't understand it. Why is there a
configuration option for this? Do both write-through and write-back
work on all machines, or could there be a case where some machine
actually requires a particular mode? If not, isn't write-back
normally "better", so you won't actually ever want to set write-through
mode?

	Arnd