Would these functions be used outside drivers/iommu? We recently added pci.h under drivers/iommu, maybe we can add a new file for these functions as well.
-Varun > -----Original Message----- > From: iommu-boun...@lists.linux-foundation.org [mailto:iommu- > boun...@lists.linux-foundation.org] On Behalf Of Alex Williamson > Sent: Saturday, May 11, 2013 2:49 AM > To: bhelg...@google.com; step...@networkplumber.org > Cc: linux-...@vger.kernel.org; iommu@lists.linux-foundation.org; > dw...@infradead.org > Subject: [PATCH 1/3] pci: Add PCI walk function and PCIe bridge test > > These will replace pci_find_upstream_pcie_bridge, which is difficult to > use and rather specific to intel-iommu usage. A quirked > pci_is_pcie_bridge function is provided to work around non-compliant > PCIe-to-PCI bridges such as those found in > https://bugzilla.kernel.org/show_bug.cgi?id=44881 > > Signed-off-by: Alex Williamson <alex.william...@redhat.com> > --- > drivers/pci/search.c | 57 > ++++++++++++++++++++++++++++++++++++++++++++++++++ > include/linux/pci.h | 23 ++++++++++++++++++++ > 2 files changed, 80 insertions(+) > > diff --git a/drivers/pci/search.c b/drivers/pci/search.c index > d0627fa..0357f74 100644 > --- a/drivers/pci/search.c > +++ b/drivers/pci/search.c > @@ -17,6 +17,63 @@ > DECLARE_RWSEM(pci_bus_sem); > EXPORT_SYMBOL_GPL(pci_bus_sem); > > +/* Test for PCIe bridges. */ > +bool pci_is_pcie_bridge(struct pci_dev *pdev) { > + if (!pci_is_bridge(pdev)) > + return false; > + > + if (pci_is_pcie(pdev)) > + return true; > + > +#ifdef CONFIG_PCI_QUIRKS > + /* > + * If we're not on the root bus, look one device upstream of the > + * current device. If that device is PCIe and is not a PCIe-to-PCI > + * bridge, then the current device is effectively PCIe as it must > + * be the PCIe-to-PCI bridge. This handles several bridges that > + * violate the PCIe spec by not exposing a PCIe capability: > + * https://bugzilla.kernel.org/show_bug.cgi?id=44881 > + */ > + if (!pci_is_root_bus(pdev->bus)) { > + struct pci_dev *parent = pdev->bus->self; > + > + if (pci_is_pcie(parent) && > + pci_pcie_type(parent) != PCI_EXP_TYPE_PCI_BRIDGE) > + > + return true; > + } > +#endif > + return false; > +} > + > +/* > + * Walk upstream from the given pdev for the first device returning > + * true for the provided match function. If no match is found, return > + * NULL. *last records the previous step in the walk. > + */ > +struct pci_dev *pci_walk_up_to_first_match(struct pci_dev *pdev, > + bool (*match)(struct pci_dev *), > + struct pci_dev **last) > +{ > + *last = NULL; > + > + if (match(pdev)) > + return pdev; > + > + *last = pdev; > + > + while (!pci_is_root_bus(pdev->bus)) { > + *last = pdev; > + pdev = pdev->bus->self; > + > + if (match(pdev)) > + return pdev; > + } > + > + return NULL; > +} > + > /* > * find the upstream PCIe-to-PCI bridge of a PCI device > * if the device is PCIE, return NULL > diff --git a/include/linux/pci.h b/include/linux/pci.h index > bd8ec30..e87423a 100644 > --- a/include/linux/pci.h > +++ b/include/linux/pci.h > @@ -1855,6 +1855,29 @@ static inline struct eeh_dev > *pci_dev_to_eeh_dev(struct pci_dev *pdev) #endif > > /** > + * pci_walk_up_to_first_match - Generic upstream search function > + * @pdev: starting PCI device to search > + * @match: match function to call on each device (true = match) > + * @last: last device examined prior to returned device > + * > + * Walk upstream from the given device, calling match() at each device. > + * Returns the first device matching match(). If the root bus is > +reached > + * without finding a match, return NULL. last returns the N-1 step in > + * the search path. > + */ > +struct pci_dev *pci_walk_up_to_first_match(struct pci_dev *pdev, > + bool (*match)(struct pci_dev *), > + struct pci_dev **last); > + > +/** > + * pci_is_pcie_bridge - Match a PCIe bridge device > + * @pdev: device to test > + * > + * Return true if the given device is a PCIe bridge, false otherwise. > + */ > +bool pci_is_pcie_bridge(struct pci_dev *pdev); > + > +/** > * pci_find_upstream_pcie_bridge - find upstream PCIe-to-PCI bridge of a > device > * @pdev: the PCI device > * > > _______________________________________________ > iommu mailing list > iommu@lists.linux-foundation.org > https://lists.linuxfoundation.org/mailman/listinfo/iommu _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
