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Cc: tglx@linutronix.de, "Sergei Shtylyov" <sshtylyov@ru.mvista.com>,
       linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org
From: Segher Boessenkool <segher@kernel.crashing.org>
Subject: Re: [PATCH 2.6.21-rt2] PowerPC: decrementer clockevent driver
Date: Sat, 19 May 2007 14:28:14 +0200
To: "Albert Cahalan" <acahalan@gmail.com>
Sender: linux-kernel-owner@vger.kernel.org
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>> Unfortunately, FIT exists only on Book E CPUs and MPC74xx aren't Book 
>> E, IIUC.
>
> By the name "FIT" perhaps, but MPC74xx has essentially
> the same thing.

> Set MMCR0[TBEE], set MMCR0[PMXE], and choose a TBL bit via 
> MMCR0[TBSEL].

That's the performance monitor, which could very well be
in use already (for performance monitoring stuff, who
would have guessed).

> It's also possible to trigger on the CPU cycle counter, but this would
> cost one of the performance counters. MPC7400 has 4, later CPUs have 6
> or more, and I think xPC7x0 had only 2.

7xx has at least four as well.


Segher

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