mirror of
https://github.com/xcat2/xNBA.git
synced 2024-11-22 17:41:55 +00:00
53 lines
2.1 KiB
Plaintext
53 lines
2.1 KiB
Plaintext
|
From: "Paolo Marini" <paolom@prisma-eng.it>
|
||
|
|
Subject: Etherboot on bare metal
|
||
|
|
Date: Tue, 10 Apr 2001 23:19:19 +0200
|
||
|
|
Organization: Prisma Engineering srl
|
||
|
|
|
||
|
|
Hi Ken,
|
||
|
|
I have ported Etherboot on an embedded, biosless platform and would like
|
||
|
|
to contribute the code.
|
||
|
|
|
||
|
|
Essentially, the hardware I was running Etherboot is a Pentium based
|
||
|
|
embedded system, with an Intel Chipset, *but* without serial, VGA,
|
||
|
|
keyboard etc., only an 82559 Intel (custom) Ethernet controller (I debug
|
||
|
|
it with the etheral Ethernet packet analyser and an emulator).
|
||
|
|
|
||
|
|
What I did was:
|
||
|
|
|
||
|
|
a.. integrate the init.s file within the firmware, with GDT
|
||
|
|
(re)initialisation (a simple and single entry point taking control of
|
||
|
|
the boot process)
|
||
|
|
b.. provide some stupid BIOS stubs in order to let the OS boot and
|
||
|
|
still belive that an INT10 call goes to the BIOS
|
||
|
|
c.. provide some basic functions to Etherboot, like timer (I used the
|
||
|
|
Pentium TSC internal counter)
|
||
|
|
d.. hardwire in the code information about the RAM size
|
||
|
|
The BIOS stubs are enough to boot Linux, pSOS and QNX with bootp. QNX is
|
||
|
|
somewhat difficult to load, because the i82559 driver tries to find the
|
||
|
|
component using the BIOS32 calls, so I had to patch it.
|
||
|
|
|
||
|
|
what i I got from the original firmware is the PCI initialisation and
|
||
|
|
resource (I/O, interrupts, memory) allocation.
|
||
|
|
|
||
|
|
I send you what I changed, that is, the initialisation code and the
|
||
|
|
misc.c file containing the timer, and the makefile (I don't remember
|
||
|
|
exactly the options I used to compile all).
|
||
|
|
|
||
|
|
Of course, it is only a good starting point for anyone wanting to
|
||
|
|
implement a bootp client on a biosless platform; some integration work
|
||
|
|
still needs to be done.
|
||
|
|
|
||
|
|
Ciao
|
||
|
|
Paolo
|
||
|
|
|
||
|
|
And in a subsequent email:
|
||
|
|
|
||
|
|
I worked with version 4.6.12, but the real modifications involve the
|
||
|
|
init.S file, which I think is quite sstable between releases. I forgot
|
||
|
|
to say that my entry point (symbol _start in init.s) assumes the
|
||
|
|
processor is already in protected mode.
|
||
|
|
|
||
|
|
[The only difference between main.c and misc.c from those in Etherboot
|
||
|
|
4.6.12 seems to be the deletion of eth_reset(). This may be of use to
|
||
|
|
others trying to make these changes work on more recent releases. Ken]
|