Sometimes we need to find PCI EXT CAP before pci_dev set up. So introduce pci_bus_find_ext_capability(), it will be used to get PCI EXT DSN before pci_dev set up. Signed-off-by: Yijing Wang <wangyijing@xxxxxxxxxx> --- drivers/pci/pci.c | 31 +++++++++++++++++++++++++++++++ include/linux/pci.h | 1 + 2 files changed, 32 insertions(+), 0 deletions(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index a263c0a..432ac86 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -327,6 +327,37 @@ int pci_find_ext_capability(struct pci_dev *dev, int cap) } EXPORT_SYMBOL_GPL(pci_find_ext_capability); +/** + * pci_bus_find_ext_capability - Find an extended capability + * @bus: the PCI bus to query + * @devfn: PCI device to query + * @cap: capability code + * + * Like pci_find_ext_capability() but works for pci devices that do not have a + * pci_dev structure set up yet. + * + * Returns the address of the requested capability structure within the + * device's PCI configuration space or 0 in case the device does not + * support it. + * + * */ +int pci_bus_find_ext_capability(struct pci_bus *bus, int devfn, int cap) +{ + int pos; + u32 status; + + pos = pci_bus_find_capability(bus, devfn, PCI_CAP_ID_EXP); + if (!pos) + return 0; + + if (pci_bus_read_config_dword(bus, devfn, PCI_CFG_SPACE_SIZE, &status) != + PCIBIOS_SUCCESSFUL || status == 0xffffffff) + return 0; + + return pci_find_next_ext_capability(bus, devfn, 0, cap); +} + + static int __pci_find_next_ht_cap(struct pci_dev *dev, int pos, int ht_cap) { int rc, ttl = PCI_FIND_CAP_TTL; diff --git a/include/linux/pci.h b/include/linux/pci.h index df495e9..470de02 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -797,6 +797,7 @@ int pci_find_capability(struct pci_dev *dev, int cap); int pci_find_next_capability(struct pci_dev *dev, u8 pos, int cap); int pci_find_ext_capability(struct pci_dev *dev, int cap); int pci_find_next_ext_capability(struct pci_bus *bus, int devfn, int pos, int cap); +int pci_bus_find_ext_capability(struct pci_bus *bus, int devfn, int cap); int pci_find_ht_capability(struct pci_dev *dev, int ht_cap); int pci_find_next_ht_capability(struct pci_dev *dev, int pos, int ht_cap); struct pci_bus *pci_find_next_bus(const struct pci_bus *from); -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html