Subject: Re: Low Power Arm Board
To: Toru Nishimura <locore64@alkyltechnology.com>
From: David Laight <david@l8s.co.uk>
List: port-arm
Date: 09/17/2006 20:20:38
On Sun, Sep 17, 2006 at 09:49:34AM +0900, Toru Nishimura wrote:
>
> - control transition from bootloader to NetBSD is always pain since
> it's common that vaddr arrangement of bootloader disagrees with
> what NetBSD expects. This may end up with large amount of sweat
> and time to be spent before completing init_arm(). Every single line
> of code must be well understood. That's the most significant part.
I managed to simplify that sequence (for a well know RTOS that wants
DRAM at address 0) by running the bootloader ROM code from its hardware
aliases at 32MB - allowing the bootloader code to enable the mmu with
a similar mapping to the OS required without having to do a 'dance of
death'.
(dunno if that helps with netbsd, but it might)
You do want the enable the icache and dcache during the load process,
without them bootload performance will suck.
David
--
David Laight: david@l8s.co.uk