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Re: Portmap on the Encore M3

To: Ashlesha Shintre <ashlesha@kenati.com>
Subject: Re: Portmap on the Encore M3
From: Ralf Baechle <ralf@linux-mips.org>
Date: Tue, 14 Nov 2006 13:05:03 +0000
Cc: linux-mips@linux-mips.org
In-reply-to: <1163469787.6532.26.camel@sandbar.kenati.com>
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References: <1163443607.6532.9.camel@sandbar.kenati.com> <20061113233802.GA17130@linux-mips.org> <1163469787.6532.26.camel@sandbar.kenati.com>
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On Mon, Nov 13, 2006 at 06:03:07PM -0800, Ashlesha Shintre wrote:

> > > > 16.35 BogoMIPS (lpj=8176)
> > 
> > Sounds about right if your CPU clock hapens to be 8MHz so probably not.
> > Chances the counter was missprogrammed.  Or are you running uncached?
> > Uncached will completly devastate performance.
> > 
> 
> For the AU1500 processor, the CPU Clock is derived from the PLL whose
> input is 12MHz.. Upon reading the value of the SYS_CPUPLL register in
> the calibrate_delay function, I found out that the multiplying factor is
> 40, thus, the CPU Clock frequency is 480MHz.. Thus the lpj should be
> approximately 480000 -- right?

From a CPU core like the Alchemy core I would more expect half of that
number, 240000.  That is if HZ is 1000 which I believe it was still
hardwired for kernels of the vintage you're running.

> Also I dont know what you mean by "running uncached"?

CONFIG_MIPS_UNCACHED which disables all processor caches.  Bad idea.

> Thanks a lot, I will check the problem with the serial driver -- i m
> using the 8250.c serial driver..

Use CONFIG_SERIAL_AU1X00.

  Ralf

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