Re: [PATCH 02/19] bootwrapper: Set -msoft-float and assembler target options.

On Tue, Mar 13, 2007 at 01:53:09PM +1100, Paul Mackerras wrote:

Many of these are really mine to answer...

Scott Wood writes:

quoted

Without the assembler target option, the assembler will use the old
dedicated mftb/mftbu instructions, rather than mfspr.  This causes the
boot to hang on e500, which doesn't have the dedicated instructions.

I see mftb being used for udelay in util.S, and udelay being used in
serial_edit_cmdline in serial.c.  It's somewhat bogus that we just
hard-code an assumed timebase frequency in util.S, and also bogus that

The timebase stuff was a straight copy from arch/ppc/boot/common/util.S.
I agree that its a bogus and should be fixed.

we get command line editing for serial consoles but not for OF
consoles (why should they be different?).

IIRC, a few of us talked about that on IRC way back.  The consensus
was that you would just change it with OF.  I added editing for non-OF
(should really be any fw that doesn't pass in an updated dtb (i.e.,
anything but OF and the new u-boot)) because, the cmdline would be
coming from the dtb embedded in the zImage (or from builtin_cmdline).
To change it, you have to find the dts, change it, and run 'wrapper'
(or run a pgm to set builtin_cmdline).  Seems like a lot to do for
a quick, temporary cmdline edit.

Its easy enough to add for OF, if you think its worth it.  I lack the OF
knowledge to do so though.

It looks to me like we should at least make the platform code provide
udelay (or mdelay), possibly with the aid of a helper function.

Agreed.

We
should also consider whether the command-line editing is generally
useful, or not, and whether the function to do it should be made more
generic.

IMHO, it is very useful if you have fw that doesn't update the dtb for
you (i.e., OF and u-boot).  Don't know if it makes sense for OF and/or
u-boot.

Mark