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Re: early_ioremap for MIPS

To: Ralf Baechle <ralf@linux-mips.org>
Subject: Re: early_ioremap for MIPS
From: "Maciej W. Rozycki" <macro@linux-mips.org>
Date: Fri, 8 Feb 2008 15:03:18 +0000 (GMT)
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>, Florian Fainelli <florian.fainelli@telecomint.eu>, linux-mips@linux-mips.org
In-reply-to: <20080208144417.GA22331@linux-mips.org>
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <200802071932.23965.florian.fainelli@telecomint.eu> <Pine.LNX.4.64N.0802081058350.7017@blysk.ds.pg.gda.pl> <20080208122858.GA8267@alpha.franken.de> <20080208144417.GA22331@linux-mips.org>
Sender: linux-mips-bounce@linux-mips.org
On Fri, 8 Feb 2008, Ralf Baechle wrote:

> > Jazz has the same problem. Right now it's solved by using wired tlb
> > entries. Which is sort of an early_ioremap.
> 
> One with a totally awkward API requiring the user having to know about
> the underlying TLB organization.  A better implementation wouldn't be
> hard to do, for anything that's outside of KSEG1's address range grab
> a new TLB entry if needed and wire an entry into it.  Use the same
> API as good old ioremap() and call the result early_ioremap().

 And presumably by the time paging has been set up for real, all the early 
allocations could get automatically graduated to ordinary ones, freeing up 
all the wired TLB entries set up so far and keeping the values of cookies 
obtained intact.

  Maciej

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