ARM5 (?) - PXA255

[M. Warner Losh]

In message: <43D0607F.3000404 at wwrinc.com>
            David Witten <wittend at wwrinc.com> writes:
: For what it is worth, I would really like to be able to run FreeBSD on 
: the Gumstix boards.

Assuming that you mean:
	http://www.gumstix.org/tikiwiki/tiki-index.php?page=gumstix

: In case someone's not familiar with them, they are PXA255 boards (at 
: present) with 6 or 16 MB flash, 64Mb SRAM, a MMC Flash card socket, USB, 
: I2C, SPI, and UARTS.  Very inexpensive add-ons for robotics, WiFi, 
: ethernet and other good stuff are available as well.  Essentially a 200 
: or 400MHz PDA on an 20mm x 80 mm board (like a stick of gum). The least 
: expensive board is < $100 US.

64MB is plenty of space to run FreeBSD.  The company I work for is
looking at running in 64MB, and we're thinking it will be plenty for
what we're looking at putting on the box (although sshd might be a bit
ambitious for our chip).

4MB flash will be enough for a kernel, but might not be enough for
both a kernel and a ram disk.  At least not without a lot of
subsetting work.  We're going to do some, but not likely to the level
of busybox.  Busybox might also be a good alternative, but since it is
GPL'd, our company prefers not to use it...

You'll need drivers for I2C, SPI and MMC controller.  I'm working on a
mmc stack for the board we're using, but the MMC bridge part might
have a different interface and need its own driver.

This is a doable project.

: I would also really like to have an ARM7 port, probably something that 
: could run on the Olimex LPC-H2294 board ($99 US) that has 16k + 1Mb SRAM 
:   and 256k + 4Mb Flash.
: 
: Is either of these projects feasible, and is there anyone out there who 
: has done work in either of these directions?

ARM7TDMI-S doesnt have a MMU.  You are going to have a tough time
porting FreeBSD.  Such a small amount of ram/rom also is likely to be
a problem.  While there are some ARM7 CPUswhich do have a MMU that
FreeBSD could run on (like the Cirrus Logic EP7312), I don't think the
Phillips LPC2294 is one of them.

Warner