OpenFirmware and interrupt-map

Eric W. Biederman ebiederman at
Wed Feb 4 22:27:01 CET 2004

YhLu <YhLu at> writes:

> SCSI card option rom may do several thing:
> 1. download FW from other address in the Option rom or BIOS into SCSI
> Controller, then start the controller.
> 2. Booting OS from SCSI disk.
> Some SCSI addon card has another EEPROM for FW, and the controller will work
> after power is on.
> For onboard SCSI, may spare that EEPROM and need option rom to download fw
> into it.
> The other thing for Option ROM is providing booting from SCSI disk or CDROM.
> If the System is boot from Network or other media, You may don't need this
> booting feature.
> Actually the FW download and controller starting can be done by Linux kernel
> driver.

Right.  And my experience has been that the linux driver usually
does all of that.

So I think I have come up with a decent short term strategy.  
1) Support all of the architectural hardware in small bootloaders
   like etherboot and FILO.   This can be used as the bootloader
   of the fallback image because it will be small.

2) Support all of the weird hardware with hardware with a Linux kernel.
   If something needs to be run before the Linux driver that can
   easily be done with a user space emulators.

So except for USB step one is done.  Step 2 getting the kernel up
to speed as a bootloader is going to be interesting.


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