> -----Original Message-----
> From: Wood Scott-B07421
> Sent: Wednesday, July 25, 2012 2:48 AM
> To: Jia Hongtao-B38951
> Cc: linuxppc-dev@lists.ozlabs.org; ga...@kernel.crashing.org; Wood Scott-
> B07421; Li Yang-R58472
> Subject: Re: [PATCH 3/6] powerpc/fsl-pci: Determine primary bus by
> looking for ISA node
>
> On 07/24/2012 05:20 AM, Jia Hongtao wrote:
> > PCI host bridge is primary bus if it contains an ISA node. But not all
> boards
> > fit this rule. Device tree should be updated for all these boards.
> >
> > Signed-off-by: Jia Hongtao <b38...@freescale.com>
> > Signed-off-by: Li Yang <le...@freescale.com>
> > ---
> > arch/powerpc/include/asm/pci-bridge.h | 1 +
> > arch/powerpc/sysdev/fsl_pci.c | 31 ++++++++++++++++++++++++-
> ------
> > arch/powerpc/sysdev/fsl_pci.h | 12 +++++++++++-
> > 3 files changed, 36 insertions(+), 8 deletions(-)
> >
> > diff --git a/arch/powerpc/include/asm/pci-bridge.h
> b/arch/powerpc/include/asm/pci-bridge.h
> > index ac39e6a..b48fa7f 100644
> > --- a/arch/powerpc/include/asm/pci-bridge.h
> > +++ b/arch/powerpc/include/asm/pci-bridge.h
> > @@ -20,6 +20,7 @@ struct device_node;
> > struct pci_controller {
> > struct pci_bus *bus;
> > char is_dynamic;
> > + int is_primary;
> > #ifdef CONFIG_PPC64
> > int node;
> > #endif
> > diff --git a/arch/powerpc/sysdev/fsl_pci.c
> b/arch/powerpc/sysdev/fsl_pci.c
> > index 99a3e78..2a369be 100644
> > --- a/arch/powerpc/sysdev/fsl_pci.c
> > +++ b/arch/powerpc/sysdev/fsl_pci.c
> > @@ -453,6 +453,7 @@ int __init fsl_add_bridge(struct device_node *dev,
> int is_primary)
> >
> > hose->first_busno = bus_range ? bus_range[0] : 0x0;
> > hose->last_busno = bus_range ? bus_range[1] : 0xff;
> > + hose->is_primary = is_primary;
> >
> > setup_indirect_pci(hose, rsrc.start, rsrc.start + 0x4,
> > PPC_INDIRECT_TYPE_BIG_ENDIAN);
> > @@ -932,18 +933,34 @@ void pci_check_swiotlb(void)
> > }
> > #endif
> >
> > -int primary_phb_addr;
> > +/*
> > + * Recursively scan all the children nodes of parent and find out if
> there
> > + * is "isa" node. Return 1 if parent has isa node otherwise return 0.
> > + */
> > +int has_isa_node(struct device_node *parent)
> > +{
> > + static int result;
> > + struct device_node *cur_child;
> > +
> > + cur_child = NULL;
> > + result = 0;
> > + while (!result && (cur_child = of_get_next_child(parent,
> cur_child))) {
> > + /* Get "isa" node and return 1 */
> > + if (of_node_cmp(cur_child->type, "isa") == 0)
> > + return result = 1;
> > + has_isa_node(cur_child);
> > + }
> > +
> > + return result;
> > +}
>
> Why are you reimplementing this? It's already in Linus's tree. See
> fsl_pci_init().
>
> Plus, your version is recursive which is unacceptable in kernel code
> with a small stack (outside of a few rare examples where the depth has a
> small fixed upper bound), and once it finds an ISA node, it returns 1
> forever, regardless of what node you pass in in the future.
>
> -Scott
About recursion I will do some more investigation.
If it finds ISA it returns 1. But for next PCI node it will return 0 if
no ISA is found (note that I set result to 0 at the beginning).
-Hongtao.
_______________________________________________
Linuxppc-dev mailing list
Linuxppc-dev@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/linuxppc-dev
