On Wed, Apr 11, 2007 at 09:40:36AM +0800, Shaohua Li wrote:
> On Tue, 2007-04-10 at 06:03 -0700, Greg KH wrote:
> > On Tue, Apr 10, 2007 at 04:11:38PM +0800, Shaohua Li wrote:
> > > On Mon, 2007-04-09 at 20:46 -0700, Greg KH wrote:
> > > > On Mon, Apr 09, 2007 at 02:55:54PM -0700, Ashok Raj wrote:
> > > > > +/*
> > > > > + * find the upstream PCIE-to-PCI bridge of a PCI device
> > > > > + * if the device is PCIE, return NULL
> > > > > + * if the device isn't connected to a PCIE bridge (that is its
> > > > > parent is a
> > > > > + * legacy PCI bridge and the bridge is directly connected to bus 0),
> > > > > return its
> > > > > + * parent
> > > > > + */
> > > > > +struct pci_dev *
> > > > > +pci_find_upstream_pcie_bridge(struct pci_dev *pdev)
> > > > > +{
> > > > > + struct pci_dev *tmp = NULL;
> > > > > +
> > > > > + if (pdev->is_pcie)
> > > > > + return NULL;
> > > > > + while (1) {
> > > > > + if (!pdev->bus->self)
> > > > > + break;
> > > > > + pdev = pdev->bus->self;
> > > > > + /* a p2p bridge */
> > > > > + if (!pdev->is_pcie) {
> > > > > + tmp = pdev;
> > > > > + continue;
> > > > > + }
> > > > > + /* PCI device should connect to a PCIE bridge */
> > > > > + BUG_ON(pdev->pcie_type != PCI_EXP_TYPE_PCI_BRIDGE);
> > > > > + return pdev;
> > > > > + }
> > > > > +
> > > > > + return tmp;
> > > > > +}
> > > >
> > > > No locking while you walk up the bus list?
> > > hmm, iommu driver didn't support pci hotplug in current stage. But we
> > > can add lock here.
> >
> > Please do, as PCI-E hotplug is much more common than PCI hotplug these
> > days (think ExpressCard in millions of laptops...)
> >
> > > > > --- linux-2.6.21-rc5.orig/include/linux/pci.h 2007-04-03
> > > > > 04:30:51.000000000 -0700
> > > > > +++ linux-2.6.21-rc5/include/linux/pci.h 2007-04-03
> > > > > 06:58:58.000000000 -0700
> > > > > @@ -126,6 +126,7 @@
> > > > > unsigned short subsystem_device;
> > > > > unsigned int class; /* 3 bytes: (base,sub,prog-if)
> > > > > */
> > > > > u8 hdr_type; /* PCI header type (`multi'
> > > > > flag masked out) */
> > > > > + u8 pcie_type; /* PCI-E device/port type */
> > > > > u8 rom_base_reg; /* which config register
> > > > > controls the ROM */
> > > > > u8 pin; /* which interrupt pin this
> > > > > device uses */
> > > > >
> > > > > @@ -168,6 +169,7 @@
> > > > > unsigned int msi_enabled:1;
> > > > > unsigned int msix_enabled:1;
> > > > > unsigned int is_managed:1;
> > > > > + unsigned int is_pcie:1;
> > > >
> > > > Do you really need both fields? Wouldn't just the pcie_type one work
> > > > (with some NOT_PCIE type being set for it if it isn't I suppose.)
> > > There are some encodings are reserved for future. Just don't want to use
> > > reserved bits, as we don't know which one is proper for NOT_PCIE.
> >
> > What are the current encodings? I don't have my copy of the pci spec
> > availble at the moment...
> 0 - 1010b is defined. Other bits are reserved. How about the pcie_type's
> highest bit determines NOT_PCIE? the pcie spec just use 4 bits for pcie
> type.
No, nevermind, it's fine to use two variables, it would just be too
messy to put them in the same one with no real benifit.
thanks,
greg k-h
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