Messages in this thread | | | Date | Wed, 06 Oct 2004 14:54:09 -0500 | From | Colin Ngam <> | Subject | Re: [PATCH] 2.6 SGI Altix I/O code reorganization |
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Grant Grundler wrote:
> Colin, > thanks for ACKing the feedback. > I think there is still some confusion... > > On Wed, Oct 06, 2004 at 02:09:54PM -0500, Colin Ngam wrote: > ... > > > Mathew explained replacing the raw_pci_ops pointer is the Right Thing > > > and I suspect it's easier to properly implement. > > > > I believe we did just that. We did not touch pci_root_ops. > > Correct. The patch ignores/overides pci_root_ops with sn_pci_root_ops > (which is what I originally suggested). > > Mathew's point was only raw_pci_ops needs to point at a different > set of struct pci_raw_ops (see include/linux/pci.h).
Hi Grant,
Well, I am confused then.
Originally, we needed to use pci_root_ops in io_init.c to pass it to pci_scan_bus(). But pci_root_ops is defined as a static in pci/pci.c. We took out the static so that we can use this in io_init.c. However, it sounded like you guys do not want to externalize pci_root_ops. Okay, we created sn_pci_root_ops.
We do not want pci_raw_ops to point at anything different. It is exactly what we needed now that we have implemented in our Prom all the pci config read/write SAL calls.
> > > > > I realize that's not easy to add/maintain in the arch/ia64 port though > > > since pcibios_fixup_bus() is common code for multiple platforms. > > > > Yes, would anybody allow us to make a platform specific callout > > from within generic pcibios_fixup_bus()??? > > If it can be avoided, preferably not. But that's up to Jesse/Tony I think. > > ... > > > It means we are telling PCI subsystem to walk root busses that don't > > > exist in all configurations. I hope there are no nasty side effects > > > from that. > > > > Not at all. If you look at the loop, sn_pci_fixup_bus(0 gets called for 0 - > > PCI_BUSES_TO_SCAN but if the bus does not exist, > > Can you quote the bit of the patch which implements "if the bus does not > exist" check? > I can't find it.
In the routine sn_pci_fixup_bus()
+static void sn_pci_fixup_bus(int segment, int busnum) +{ + int status = 0; + int nasid, cnode; + struct pci_bus *bus; + struct pci_controller *controller; + struct pcibus_bussoft *prom_bussoft_ptr; + struct hubdev_info *hubdev_info; + void *provider_soft; + + status = + sal_get_pcibus_info((u64) segment, (u64) busnum, + (u64) ia64_tpa(&prom_bussoft_ptr)); + if (status > 0) { + return; /* bus # does not exist */ + } + + prom_bussoft_ptr = __va(prom_bussoft_ptr); + controller = sn_alloc_pci_sysdata(); + if (!controller) { + BUG(); + } + + bus = pci_scan_bus(busnum, &sn_pci_root_ops, controller); + if (bus == NULL) { + return; /* error, or bus already scanned */ + }
We bail if sal_get_pcibus_info() is not successful. Am I missing something?
> > > > One favour. Would you agree to letting this patch be included by Tony > > and we will come up with another patch to fix the 2 obvious items listed > > above? It will be great to avoid spinning this big patch. > > I think that's up to Jesse/Tony. > I don't "own" any of the code in question. > Just trying to undo the confusion I caused.
Thanks.
colin
> > > grant
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