Re: [loongson-PATCH-v3 17/25] add a machtype kernel command line argument

[Wu Zhangjin <wuzhangjin@gmail.com>]

On Thu, 2009-06-04 at 15:51 +0200, Arnaud Patard wrote:
> wuzhangjin@gmail.com writes:
> 
> Hi,
> 
> > From: Wu Zhangjin <wuzj@lemote.com>
> >
> > the difference between yeeloong-7inch and yeeloong-8.9inch is very
> > small, only including the screen size and shutdown logic. so, it's very
> > important to share the same kernel image file between them instead of
> > adding some new kernel config options. benefit from this, the
> > distribution developers only have a need to compile the kernel one time.
> >
> > to share the same kernel image file between yeelooong-7inch and
> > yeeloong-8.9inch, there is a need to add a kernel command line, here I
> > name is machtype, it works like this:
> >
> >     machtype=lemote-yeeloong-2f-7inch
> >           company - product - cpu revision - size
> 
> I'm curious. Why can't you use the boot monitor to pass the right
> machine type instead ? iirc, you're using pmon and pmon has a variable
> called "systype". If the systype variable is not designed for that, I'll
> be happy to know its use :)
> 

yes, I just checked the PMON variables, there is "systype" there, but
seems can not be set(when reboot, will become the original one), maybe
hard-coded in PMON? so i added another PMON variable: machtype, and
added some source code: if there is a PMON machtype variable there,
transfer it to a kernel command line.

but i think using a kernel command line is better, because we can either
set it as the karg variable in PMON or pass it in the boot.cfg, which is
more flexible and in-dependent from the bootloader.

and perhaps, someday, we can share the same kernel image file between
fuloong2f box and yeeloong2f laptop via this kernel command line:
machtype, because there is really only a few difference between
them(only the reboot/shutdown logic, serial port). I really want to
share them and remove one of the irq.c file :-)

thanks!
Wu Zhangjin

> 
> Arnaud