Re: [Qemu-ppc] [PATCH 5/5] PPC: e500: Select MPIC v4.2 on ppce500 platform

[Scott Wood]

On 01/25/2013 10:38:39 AM, Scott Wood wrote:
> On 01/25/2013 07:03:02 AM, Alexander Graf wrote:
> > On 22.01.2013, at 02:53, Scott Wood wrote:
> >
> > > The compatible string is changed to fsl,mpic on all e500  
> > platforms, to
> > > advertise the existence of BRR1.  This matches what the device  
> > tree will
> > > have on real hardware.
> > >
> > > With MPIC v4.2 max_cpu can be increased from 15 to 32.
> > >
> > > Signed-off-by: Scott Wood <address@hidden>
> > > ---
> > > hw/ppc/e500.c      |    4 ++--
> > > hw/ppc/e500.h      |    2 ++
> > > hw/ppc/e500plat.c  |    4 +++-
> > > hw/ppc/mpc8544ds.c |    2 ++
> > > 4 files changed, 9 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/hw/ppc/e500.c b/hw/ppc/e500.c
> > > index 530f929..b7474c0 100644
> > > --- a/hw/ppc/e500.c
> > > +++ b/hw/ppc/e500.c
> > > @@ -297,7 +297,7 @@ static int  
> > ppce500_load_device_tree(CPUPPCState *env,
> > >     snprintf(mpic, sizeof(mpic), "%s/address@hidden", soc,  
> > MPC8544_MPIC_REGS_OFFSET);
> > >     qemu_devtree_add_subnode(fdt, mpic);
> > >     qemu_devtree_setprop_string(fdt, mpic, "device_type",  
> > "open-pic");
> > > -    qemu_devtree_setprop_string(fdt, mpic, "compatible",  
> > "chrp,open-pic");
> > > +    qemu_devtree_setprop_string(fdt, mpic, "compatible",  
> > "fsl,mpic");
> >
> > Actually, thinking about this once more, would older kernels  
> > continue to work with "fsl,mpic"? Did the kernels that first  
> > introduced the qemu ppc machine already support "fsl,mpic" or would  
> > they rely on "chrp,open-pic"?
>
> fsl,mpic has been there longer than the qemu ppc machine.

In any case, one of the reasons the new compatible was introduced was  
because people didn't like claiming compatibility with chrp,open-pic  
after we changed #interrupt-cells (which we haven't done yet in QEMU,  
but at some point probably will).  The device trees you'd find when  
running on real hardware will not have a chrp,open-pic compatible (at  
least, the e500v2 ones don't -- the e500mc trees have both, but  
shouldn't).

-Scott