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Re: MPC8260 cache patch

From: Jonathan Larmour <jifl at eCosCentric dot com>
To: Patrick Doyle <wpd at delcomsys dot com>
Cc: Gary Thomas <gary at mlbassoc dot com>,eCos patches <ecos-patches at sources dot redhat dot com>
Date: Sun, 30 Mar 2003 18:24:49 +0100
Subject: Re: MPC8260 cache patch
References: <NFBBJAJICAKJPMMKDAGBOELMDNAA.wpd@delcomsys.com>

Patrick Doyle wrote:

So, here is my question:

Why don't we always use the "dcbf" instruction

I'll let Nick (the original PPC HAL author) and Gary work that one out. I'm sure the difficulty is because the API isn't quite rich enough to differentiate between the two operations - someone who wants to sync doesn't necessarily want to invalidate.

On a related but different topic, I'm still not to sure about the disable
vs. disable and invalidate point.  It still sounds familiar to me, but I
don't see anything like that in the OMAP documenation (Jonathan's point
about it being one of Jesper's ports has me really worried here).  Perhaps
it was back when I was reading the MIPS book...

I think we're pretty convinced now that we have to leave it as it is if we want it to remain portable. It's not like flash operations are fast enough that the overhead of the invalidate will matter much.

Jifl
--
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--[ "You can complain because roses have thorns, or you ]--
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References:
- RE: MPC8260 cache patch
  - From: Patrick Doyle

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