Re: [RFC PATCH] arm: kernel: pci: remove pci=firmware command line parameter handling

[Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>]

On Mon, Feb 29, 2016 at 04:56:53PM -0600, Bjorn Helgaas wrote:
> On Mon, Feb 29, 2016 at 05:43:20PM +0000, Lorenzo Pieralisi wrote:
> > According to kernel documentation, the pci=firmware command line
> > parameter is only meant to be used on IXP2000 ARM platforms to prevent
> > the kernel from assigning PCI resources configured by the bootloader.
> > 
> > Since the IXP2000 ARM platforms support has been removed from the
> > kernel in commit:
> > 
> > commit c65f2abf54a6 ("ARM: remove ixp23xx and ixp2000 platforms")
> > 
> > its platforms specific kernel parameters should be removed
> > too from the kernel documentation along with the kernel code
> > currently handling them in that they have just become obsolete.
> > 
> > This patch removes the pci=firmware command line parameter handling
> > from ARM code and the related kernel parameters documentation
> > section.
> > 
> > Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> 
> Acked-by: Bjorn Helgaas <bhelgaas@google.com>

Thank you !

> It looks like Rob merged c65f2abf54a6, so maybe he will merge this as
> well?  Otherwise I'd be happy to merge it; just let me know if you
> want me to.

Hopefully the kernel parameter description matches current usage
on ARM systems, it could affect all ARM 32-bit platforms (if any ?) that
abused the pci=firmware parameter, it is just impossible for me to check
(that's why I posted it as an RFC. It would be very good to remove that
kernel parameter though).

Having said that, either way of merging it is fine by me, I can send it
to Russell's patch system too, given that there are already patches queued
to remove PCI_PROBE_ONLY from some PCI host controllers I am happy for it
to go via PCI tree.

Rob, Russell, any preferences ?

Thanks !
Lorenzo

> 
> > Cc: Arnd Bergmann <arnd@arndb.de>
> > Cc: Lennert Buytenhek <kernel@wantstofly.org>
> > Cc: Jonathan Corbet <corbet@lwn.net>
> > Cc: Bjorn Helgaas <bhelgaas@google.com>
> > Cc: Rob Herring <robh@kernel.org>
> > Cc: Russell King <linux@arm.linux.org.uk>
> > ---
> >  Documentation/kernel-parameters.txt | 5 -----
> >  arch/arm/kernel/bios32.c            | 3 ---
> >  2 files changed, 8 deletions(-)
> > 
> > diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
> > index 9a53c92..e213acc 100644
> > --- a/Documentation/kernel-parameters.txt
> > +++ b/Documentation/kernel-parameters.txt
> > @@ -2875,11 +2875,6 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
> >  				for broken drivers that don't call it.
> >  		skip_isa_align	[X86] do not align io start addr, so can
> >  				handle more pci cards
> > -		firmware	[ARM] Do not re-enumerate the bus but instead
> > -				just use the configuration from the
> > -				bootloader. This is currently used on
> > -				IXP2000 systems where the bus has to be
> > -				configured a certain way for adjunct CPUs.
> >  		noearly		[X86] Don't do any early type 1 scanning.
> >  				This might help on some broken boards which
> >  				machine check when some devices' config space
> > diff --git a/arch/arm/kernel/bios32.c b/arch/arm/kernel/bios32.c
> > index 066f7f9..05e61a2 100644
> > --- a/arch/arm/kernel/bios32.c
> > +++ b/arch/arm/kernel/bios32.c
> > @@ -550,9 +550,6 @@ char * __init pcibios_setup(char *str)
> >  	if (!strcmp(str, "debug")) {
> >  		debug_pci = 1;
> >  		return NULL;
> > -	} else if (!strcmp(str, "firmware")) {
> > -		pci_add_flags(PCI_PROBE_ONLY);
> > -		return NULL;
> >  	}
> >  	return str;
> >  }
> > -- 
> > 2.5.1
> > 
> > --
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