From: llee <llee@huawei.com>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: linuxppc-dev list <linuxppc-dev@lists.linuxppc.org>
Subject: Re: fail to disable MMU on ppc 8241
Date: Tue, 20 Apr 2004 09:45:55 +0800 [thread overview]
Message-ID: <408480D3.1030009@huawei.com> (raw)
In-Reply-To: <1082352050.1689.9.camel@gaston>
Benjamin Herrenschmidt wrote:
>On Mon, 2004-04-19 at 13:55, llee wrote:
>
>
>>Hi, there,
>>I boot linux (2.6.3) on my ppc 8241 through vxworks bootloader. I'd got
>>a port (on address 0x70020006) to constrol three LEDs, so I could know
>>where the kernel going. But after the disable_mmu is called, I lost
>>control to the LEDs, Any suggestion on this? As I know, vxworks use a
>>one-to-one mapping MMU setup, I should must constrol the LEDs through
>>the same address.
>>
>>
>
>With mmu off, I suspect the 8241 acts as if the entire address space
>was cacheable, which is a BAD THING for IOs typically.
>
>Ben.
>
>
>
>
>
>
Thanks Ben, It works when I disable DATA CACHE!
** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/
prev parent reply other threads:[~2004-04-20 1:45 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-04-19 3:55 fail to disable MMU on ppc 8241 llee
2004-04-19 5:20 ` Benjamin Herrenschmidt
2004-04-20 1:45 ` llee [this message]
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