Re: [RFC 5/5] powerpc/fsl: Add supported-irq-ranges for P2020

[Scott Wood <oss@buserror.net>]

On Wed, 2018-08-08 at 03:44 +0000, Bharat Bhushan wrote:
> > -----Original Message-----
> > From: Scott Wood [mailto:oss@buserror.net]
> > Sent: Wednesday, August 8, 2018 2:44 AM
> > To: Bharat Bhushan <bharat.bhushan@nxp.com>;
> > benh@kernel.crashing.org; paulus@samba.org; mpe@ellerman.id.au;
> > galak@kernel.crashing.org; mark.rutland@arm.com;
> > kstewart@linuxfoundation.org; gregkh@linuxfoundation.org;
> > devicetree@vger.kernel.org; linuxppc-dev@lists.ozlabs.org; linux-
> > kernel@vger.kernel.org
> > Cc: robh@kernel.org; keescook@chromium.org; tyreld@linux.vnet.ibm.com;
> > joe@perches.com
> > Subject: Re: [RFC 5/5] powerpc/fsl: Add supported-irq-ranges for P2020
> > 
> > On Fri, 2018-07-27 at 15:18 +0530, Bharat Bhushan wrote:
> > > MPIC on NXP (Freescale) P2020 supports following irq
> > > ranges:
> > >   > 0 - 11      (External interrupt)
> > >   > 16 - 79     (Internal interrupt)
> > >   > 176 - 183   (Messaging interrupt)
> > >   > 224 - 231   (Shared message signaled interrupt)
> > 
> > Why don't you convert to the 4-cell interrupt specifiers that make dealing
> > with these ranges less error-prone?
> 
> Ok , will do if we agree to have this series as per comment on other patch.

If you're concerned with errors, this would be a good things to do regardless.
 Actually, it seems that p2020si-post.dtsi already uses 4-cell interrupts.

What is motivating this patchset?  Is there something wrong in the existing
dts files?


> 
> > 
> > > diff --git a/arch/powerpc/platforms/85xx/mpc85xx_rdb.c
> > > b/arch/powerpc/platforms/85xx/mpc85xx_rdb.c
> > > index 1006950..49ff348 100644
> > > --- a/arch/powerpc/platforms/85xx/mpc85xx_rdb.c
> > > +++ b/arch/powerpc/platforms/85xx/mpc85xx_rdb.c
> > > @@ -57,6 +57,11 @@ void __init mpc85xx_rdb_pic_init(void)
> > >  			MPIC_BIG_ENDIAN |
> > >  			MPIC_SINGLE_DEST_CPU,
> > >  			0, 256, " OpenPIC  ");
> > > +	} else if (of_machine_is_compatible("fsl,P2020RDB-PC")) {
> > > +		mpic = mpic_alloc(NULL, 0,
> > > +		  MPIC_BIG_ENDIAN |
> > > +		  MPIC_SINGLE_DEST_CPU,
> > > +		  0, 0, " OpenPIC  ");
> > >  	} else {
> > >  		mpic = mpic_alloc(NULL, 0,
> > >  		  MPIC_BIG_ENDIAN |
> > 
> > I don't think we want to grow a list of every single revision of every
> > board in
> > these platform files.
> 
> One other confusing observation I have is that "irq_count" from platform
> code is given precedence over "last-interrupt-source" in device-tree.
> Should not device-tree should have precedence otherwise there is no point
> using " last-interrupt-source" if platform code passes "irq_count" in
> mpic_alloc().

Maybe, though I don't think it matters much given that last-interrupt-source
was only added to avoid having to pass irq_count in platform code.

-Scott