[U-Boot-Users] U-Boot-NG ?

[Sascha Hauer]

On Mon, Jul 02, 2007 at 01:22:43PM -0400, Jerry Van Baren wrote:
> Sascha Hauer wrote:
> > Hi,
> > 
> > I just prepared a git repository for our U-Boot-NG proposal. Do a
> > 
> > git clone http://iocaste.extern.pengutronix.de/git/U-Boot-NG.git
> > 
> > (no native git support at the moment)
> > 
> > There is also a tarball snapshot available here:
> > 
> > http://pengutronix.de/software/ptxdist/temporary-src/U-Boot-NG-20070702.tar.gz
> > 
> > This is only a temporary place for the source, further development should
> > probably either be done on Wolgangs server or some other dedicated
> > server.
> > The tree is based on vanilla U-Boot-1.2.0.
> > 
> > As a starting point I've included the README in this mail. It's also
> > included in the source tree under README.u2. Further documentation can be
> > found under Documentation/ and of course in the code ;)
> > 
> > Regards,
> >   Sascha Hauer
> 
> Hi Sascha,
> 
> This is very, very interesting.  One stupid ;-) question, what sort of 
> trade-offs are we looking at, other than the lack of backwards support 
> of various boards?  In particular, how does the memory footprint compare 
> for an equivalently configured target?

Hi Jerry,

The image space needed has not significantly changed. On Arm it's slightly
bigger if you enable the same features. But on Arm you do not need zlib,
which is configurable now. This saves you around 15k.
The PowerPC images got smaller than before. The code is not position
independent anymore, this saves around 10% of binary space.
Console support has been rewritten. Together with the list implementation
which was only used for console this gained 5k. The environment support
was very complicated with the serial functions used on startup. With
these fixes and many other ones enough space was available to implement
filesystem support without increasing the image size.

My current Arm image (for the scb9328) is 85k, it includes hush parser,
networking and nor flash support. With cramfs enabled (zlib) it has 97k
The PowerPC image (MPC5200, Phytec Phycore board) has 127k with hush
parser, cramfs and oftree support.

I think that big U-Boot images will get smaller because there is more
infrastructure you can use. Small images may get bigger because the
infrastructure is still in place

I did not look at RAM usage, but I think that is no matter for most
boards since they have orders magnitude more RAM than U-Boot needs.

Sascha

-- 
Pengutronix - Linux Solutions for Science and Industry
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