On Mon, 2013-05-13 at 13:51 +0000, Sethi Varun-B16395 wrote: > 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.
The intention is to make them generic enough for pci-core, unlike pci_find_upstream_pcie_bridge, which was rather specific to iommu usage. Thanks, Alex > > -----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
