Meta Boot Loader

[Johnson, Erik J]

> If the boot loader can load our code directly, this is just what we
> want.  I guess we just need to get the details of the initial boot
> loader.  For example, what is the format of the file it pulls over?

a.out, if I remember the code correctly.  After pulling it down, it
will jump to the entry point given in the a.out header.

> Where in memory is the image placed?  (i.e., where do we need to
> link our text, bss, and data sections.)

there should be MACROs and a routine that determines this in
the BSP (BoardSupport/VxWorks/...../sysLib.c) (sorry I don't
have the code handy right now, so I might have
the names wrong).  But look for things of the
nature like sysMemTop() and SYS_MEM???.  The memory map
given in in the HRM might also provide the information.

erik

> 
> -Scott
> 
> 
> Raghunandan, Makaram writes:
> > 
> > The VxWorks boot image that is on the Flash ROM of IXP1200 
> Evaluation
> > system does exactly what you need.  The initial boot loader comes up
> > initializes the Chip, and, the Ethernet NIC.  After that the full
> > suite of VxWorks is pulled over from the network.  Now, in 
> your case,
> > you can use this method to load your OS rather than the 
> default file.
> >
> > Another alternative is to use the Angel Debug Monitor that is also
> > loaded on the FlashROM. The ARM SDT (from ARM LTD.) can be used in
> > conjunction with this to load any program on to the StrongARM core.
> > 
> > -----Original Message-----
> > From: Scott C. Karlin [mailto:scott at CS.Princeton.EDU]
> > Sent: Wednesday, April 19, 2000 8:27 PM
> > To: ixp1200 at CS.Princeton.EDU
> > Subject: Meta Boot Loader
> > 
> > 
> > We'd like to begin porting our own operating system (Scout)
> > to the StrongARM core of the IXP1200.  To do this we'll
> > need a way to get code into the device.  We have a couple
> > of thoughts on this and would like to get some feedback
> > (especially from the Intel folks who are on the list).
> > We basically need a way to load a raw image into the core
> > and start running it.  We are not using VxWorks or eCOS.
> > 
> > Approaches:
> > 
> >    1.  Purchase or lease a NetROM device.
> >    2.  Use a device programmer to program the flash EEPROM.
> >        Is the flash in a socket?  The chip packaging looks
> >        unfamiliar.
> >    3.  Use a Meta Boot Loader.  This is code that runs
> >        under VxWorks.  The preprogrammed boot loader in
> >        ROM can load the meta boot loader which will, in
> >        turn, load our OS code.  
> > 
> > Number 3 has the advantage that it is an all software solution.
> > The problem is that it appears to need a VxWorks executable
> > (the meta boot loader) but we aren't interested in purchasing
> > a license for this one little program.  Is this something
> > that someone else has done (or could do)?
>