Option Parameters for Linuxbios.

[Peter Stuge]

Hi, I've been confused by these commands and options too.  Below are some
suggested namechanges followed by some reasoning about documentation in
general.


On Sat, Jan 11, 2003 at 12:48:06PM -0500, steven james wrote:
> > biosbase 0xffff0000
> 
> The BIOS image will begin at the biosbase address in the CPU's memory
> space

imagephysaddr
or
stage1physaddr


> > rambase 0x00000800
> Once RAM is set up, the C portion of LinuxBIOS will be uncompressed and
> loaded to rambase in system memory.

cportionramaddr
or
stage2ramaddr


> > option XIP_ROM_BASE=0xffff0000
> 
> same as biosbase

XIP_IMAGE_PHYS_ADDR

Why is there both a command and an option for this?  And what is XIP?


> > option XIP_ROM_SIZE=0x10000
> 
> The rom size for LinuxBIOS is this size (a 64K blockmany cases)

XIP_IMAGE_SIZE  # if this accounts for the payload
or
XIP_LINUXBIOS_SIZE  # if not

Reading some Config files this doesn't seem to be the whole story, caching
is mentioned.  What's up?


> > option STACK_SIZE=0x2000
> 
> This is the size of RAM allocated for the stack used by the C code

C_STACK_SIZE  # for cportionramaddr
or
STAGE2_STACK_SIZE  # for stage2ramaddr

Already pretty good the way it is but adding the context should help.


> > option ZKERNEL_START=0xfff40000
> 
> This is where the payload (such as etherboot) will be located in the
> memory space (as part of the flash).

PAYLOAD_PHYS_ADDR

Does LinuxBIOS require this to be aligned in any way?


> > option ZKERNEL_MASK=0x3ed
> 
> Near as I can tell, this is just a legacy now.

Great, then it can be removed.  :)  What has it been used for?


I'd be happy to make these changes.

What about general documentation, e.g. regarding current LinuxBIOS structure?
I know I've read about the different parts of LinuxBIOS somewhere but it
might have been here on the mailing list.  I'm thinking of the stage1/stage2
names I used above, is it a good idea to establish a stage 1 and a stage 2
(or similar) of LinuxBIOS or should it just continue to be "in assembly"
and "in C" ?

Also, I would very much like a complete documenatation of the Config files,
I'm thinking about doing something along the lines of a Capabilities or
Options file that specifies all possible (used) options for that particular
directory, along with sane default values where possible.  It might only
apply to mainboards but would be useful for learning the structure, when
porting to new mainboards and for the web Config creator.  Thoughts?


//Peter