OF access after kernel boot

OF access after kernel boot

[Vladimir Simonov]

Hi all,
I'd like to change some OF (Open Firmware)
parameters after kernel loading. But arch/ppc/prom.c
runs "Because OF may have mapped I/O devices into the area
starting at KENELBASE,....Therefore all OF calls should be
done within prom_init()...".
Is it possible to keep safe interface to OF
after kernel's mapping to KERNELBASE?
If it is not possible for all PPC, perhaps,
a list of mashines where it works and
some hints how to do it will be useful.

Thanks in advance
Vladimir Simonov

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Re: OF access after kernel boot

[Simon Piette]

Hi,

* Vladimir Simonov (sv@asplinux.ru) [000704 03:40]:
>
> Hi all,
> I'd like to change some OF (Open Firmware)
> parameters after kernel loading. But arch/ppc/prom.c
> runs "Because OF may have mapped I/O devices into the area
> starting at KENELBASE,....Therefore all OF calls should be
> done within prom_init()...".
> Is it possible to keep safe interface to OF
> after kernel's mapping to KERNELBASE?
> If it is not possible for all PPC, perhaps,
> a list of mashines where it works and
> some hints how to do it will be useful.
>

man nvsetenv

Without parameters, nvsetenv will give you the values of nvram
registers.

Cheers,

Simon

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Re: OF access after kernel boot

[Simon Piette]

* Vladimir Simonov (sv@asplinux.ru) [000704 03:40]:
>
I am not sure if your machine is supported by this utility, though.

Simon

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RE: OF access after kernel boot

[Vladimir Simonov]

Thanks,
> man nvsetenv

> Without parameters, nvsetenv will give you the values of nvram
> registers.
I'm using linux-pmac-stable - 2.2.15pre19 on G4. And found that nvram.c
is not linked in spite of CONFIG_NVRAM=y.
Makefile in drivers/char contains
....
ifeq($(CONFIG_NVRAM),y)
	ifeq($(CONFIG_PPC),)
....
Is an absence of "y" a typo or has sence?
Any way nvram.c can't be compiled "for this machine configuration".
Does anybody know which versions of kernel permit
nvram using on G4, iBook?
Thanks again
Vladimir Simonov

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