RM9200 tuning

[M. Warner Losh]

In message: <20100308233822.GC19800 at cicely7.cicely.de>
            Bernd Walter <ticso at cicely7.cicely.de> writes:
: On Mon, Mar 08, 2010 at 04:06:22PM -0700, M. Warner Losh wrote:
: > In message: <20100308225420.GB19800 at cicely7.cicely.de>
: >             Bernd Walter <ticso at cicely7.cicely.de> writes:
: > : On Mon, Mar 08, 2010 at 02:38:50PM -0800, Stanislav Sedov wrote:
: > : > On Mon, 8 Mar 2010 22:32:57 +0100
: > : > Bernd Walter <ticso at cicely7.cicely.de> mentioned:
: > : > 
: > : > > Well I still don't use a real loader, just the plain bootcode.
: > : > > I would be very happy to switch to loader(8) with FICL, tuneables and
: > : > > bootpromt.
: > : > > Is it possible to do today?
: > : > > I was with Warner using my elfbuild hardware for the first time when he
: > : > > did the first steps on RM9200.
: > : > > Therefor I'm probably still using obsolete old quick and dirty hacks.
: > : > > If loader(8) can be used now it is the first thing I will change before
: > : > > trying anything else.
: > : > 
: > : > I belive it should be pretty easy to port ubldr(8) to support AT91 as raj@ made it
: > : > working on the Marverll ARM platform.  I'm not sure which details should be
: > : > reimplemented, though, but from what I seen it should be quite a little work
: > : > required.
: > : > 
: > : > I'm just using plain uboot loading direclty from flash without Atmel 1st level
: > : > loader and then use uboot to load FreeBSD kernel/pass hints and kenv variables.
: > : > I think I posted the relevant code a couple of times to the list, but maybe it
: > : > really makes more sense to port loader(8) instead as my code isn't going to make
: > : > it into the official uboot distribution.
: > : 
: > : The ability to configure kenv variables is a big win.
: > : I'm using sys/boot/arm/at91/boot2 from spiflash instead of uboot, which
: > : directly starts the kernel.
: > : The kernel has ugly hardcoded things, such as rootdev and hints.
: > : There is already a good amount of support for loader(8) in libat91
: > : so it shouldn't be too hard to do.
: > : I may give it a try after finishing some other projects.
: > 
: > I have an 8MB SPI flash on one of my boards...  Maybe I should get
: > /boot/loader support going with it..  as well as the different
: > GEOM_FOO partioning schemes...  Certainly would make a certain local
: > company interested...
: 
: I just thought about boot2 retrieving loader from SD instead of
: kernel.
: But you are probably right to retrieve the loader from flash instead.
: boot2 with UFS support is already too big for AT91 with just 8k SRAM.

But the AT91RM9200 has 16k :)  We are at about 9.5k, and further space
savings is difficult.

: A boot2 with just flash support would be much smaller and loader then
: can switch between netboot and such, which currently has to be hardcoded
: to keep the size down.
: My boards usually have AT45DB161D (some early boards have 321C) chips.
: Considered the loader size on i386 this should fit.
: I remeber you also worked with boards booting from I2C flash?

Yes.

Warner