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Re: address translation with TLB

To: Tom Appermont <tea@sonycom.com>
Subject: Re: address translation with TLB
From: Ralf Baechle <ralf@oss.sgi.com>
Date: Thu, 19 Apr 2001 09:57:43 -0300
Cc: linux-mips@oss.sgi.com
In-reply-to: <20010419100147.A467@ginger.sonytel.be>; from tea@sonycom.com on Thu, Apr 19, 2001 at 10:01:47AM +0200
References: <20010414102901.A13595@ginger.sonytel.be> <20010417141122.D7177@bacchus.dhis.org> <20010419100147.A467@ginger.sonytel.be>
Sender: owner-linux-mips@oss.sgi.com
User-agent: Mutt/1.2.5i
On Thu, Apr 19, 2001 at 10:01:47AM +0200, Tom Appermont wrote:

> > Sane designs make sure that peripherals are at physical addresses of 512mb
> > or less so can be addressed through KSEG1 without using TLB entries.  So
> > far the only violation of this rule are the Jazz systems.
> 
> In the setup.c file for the jazz board, is written:
> 
>         add_wired_entry (0x02000017, 0x03c00017, 0xe0000000, PM_64K);
>         add_wired_entry (0x02400017, 0x02440017, 0xe2000000, PM_16M);
>         add_wired_entry (0x01800017, 0x01000017, 0xe4000000, PM_4M);
> 
> Why do these physical addresses which are all below 512MB need TLB entries? 

These are not physical addresses but entry[01] entries so actually are
addresses outside the low 512mb.

  Ralf

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