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.
> > --- 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.
Thanks,
Shaohua
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