From: linux@arm.linux.org.uk (Russell King - ARM Linux)
To: linux-arm-kernel@lists.infradead.org
Subject: Alignment Requirement for MT_MEMORY type
Date: Thu, 18 Feb 2010 08:51:25 +0000 [thread overview]
Message-ID: <20100218085125.GA848@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <B125D8217ABC4B43826503DE00A2D44910F4639A8D@SJEXCHCCR01.corp.ad.broadcom.com>
On Wed, Feb 17, 2010 at 04:33:00PM -0800, Henry Li wrote:
> Can someone tell me why there is a requirement for the virtual and physical
> addresses and size using MT_MEMORY memtype (where prot_l1=0) to be aligned
> to section boundary (1MB) in linux-2.6.32/arch/arm/mm/mmu.c/create_mapping
> during IO table init?
Because today SDRAM is always a whole number of MB, so its pointless
defining it in terms of 4K pages. MT_MEMORY is not for general purpose
use, but only for setting up the initial kernel SDRAM mapping.
next prev parent reply other threads:[~2010-02-18 8:51 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-02-18 0:33 Alignment Requirement for MT_MEMORY type Henry Li
2010-02-18 8:51 ` Russell King - ARM Linux [this message]
2010-02-18 18:08 ` Henry Li
2010-02-19 8:44 ` Linus Walleij
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