I've searched the archives for instructions on modifying the kernel
to run on headless (no VGA or keyboard controller), and have seen only a
few references to a "serial console patch" that can be applied.
I suspect that porting Linux to headless systems has been done many times,
and I'd appreciate pointers to info.
I'm porting Linux to set of x86 embedded boards that are distinctly
NOT PC-architecture:
PII
BX northbridge
custom southbridge (no PIIX!!)
custom interrupt controller (31 separately maskable interrupt inputs)
Dec 21143 PCI ethernet controller, with MII PHY
Symbios 53C876 dual-SCSI PCI chip.
unusual I/O ports, e.g., UART at 0x1480 (instead of 0x3f8)
no VGA
no keyboard
no floppy
no IDE
no BIOS
I've written the code that configures the BX, and I've used gcc to write
a bunch of test code that bangs on all the devices, including minimal
drivers that send/receive ethernet packets and do things on the SCSI busses.
The writing of this low-level test code was necessary, for diagnostic
purposes, even if one ports an OS to the boards. However, for more
comprehensive stress testing, I'd like to get Linux ported. So far, I've
made the minor tweaks needed to bios32.c to keep it from poking about for
a BIOS, I've started the tweaks needed to have the "irq" family of routines
use our custom interrupt controller instead of those gawdawful 8259's, and
I'm finishing tweaks to tulip.c so that the driver won't get confused by the
non-standard layout of the srom.
I think I've figured out a boot procedure (put the gzipped vmlunix in my
4 Mbyte ROM and use existing gunzip code already ported to inflate it
into memory).
The major unknown is configuring the system to use the serial port for all
console operations. I can probably thrash through it myself, but why
reinvent the wheel?
Thanks,
-- bilker
