[PATCH] powerpc: Support CMDLINE_EXTEND

[Chris Packham]

Hi Christophe,

On Tue, 2019-07-30 at 09:02 +0200, Christophe Leroy wrote:
> 
> Le 24/07/2019 à 07:33, Chris Packham a écrit :
> > 
> > Device tree aware platforms can make use of CMDLINE_EXTEND to
> > extend the
> > kernel command line provided by the bootloader. This is
> > particularly
> > useful to set parameters for built-in modules that would otherwise
> > be
> > done at module insertion. Add support for this in the powerpc
> > architecture.
> > 
> > Signed-off-by: Chris Packham <chris.packham at alliedtelesis.co.nz>
> > ---
> >   arch/powerpc/Kconfig | 12 ++++++++++++
> I think you also have to implement some stuff in
> early_cmdline_parse() 
> in arch/powerpc/kernel/prom_init.c

I my case I didn't need to since the generic code in drivers/of/fdt.c
did what I need. For early options or platforms that don't use a device
tree then I can see why I'd need the update to update to prom_init.

> 
> Maybe look at https://patchwork.ozlabs.org/patch/1074126/
> 

Do you mind if I take this and fold it into a v2 of my patch? Any
particular reason it didn't get picked up in April?

> Christophe
> 
> > 
> >   1 file changed, 12 insertions(+)
> > 
> > diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> > index d8dcd8820369..cd9b3974aa36 100644
> > --- a/arch/powerpc/Kconfig
> > +++ b/arch/powerpc/Kconfig
> > @@ -851,6 +851,11 @@ config CMDLINE
> >   	  some command-line options at build time by entering
> > them here.  In
> >   	  most cases you will need to specify the root device
> > here.
> >   
> > +choice
> > +	prompt "Kernel command line type" if CMDLINE != ""
> > +	default CMDLINE_FORCE
> > +	depends on CMDLINE_BOOL
> > +
> >   config CMDLINE_FORCE
> >   	bool "Always use the default kernel command string"
> >   	depends on CMDLINE_BOOL
> > @@ -860,6 +865,13 @@ config CMDLINE_FORCE
> >   	  This is useful if you cannot or don't want to change
> > the
> >   	  command-line options your boot loader passes to the
> > kernel.
> >   
> > +config CMDLINE_EXTEND
> > +	bool "Extend bootloader kernel arguments"
> > +	help
> > +	  The command-line arguments provided by the boot loader
> > will be
> > +	  appended to the default kernel command string.
> > +endchoice
> > +
> >   config EXTRA_TARGETS
> >   	string "Additional default image types"
> >   	help
> >