From 44a9a36f6be43636ac2342c06d9feb60db77826a Mon Sep 17 00:00:00 2001 From: Bjorn Helgaas Date: Fri, 13 Jul 2012 14:24:59 -0600 Subject: [PATCH] PCI: Add pci_find_next_ext_capability() Some extended capabilities, e.g., the vendor-specific capability, can occur several times. The existing pci_find_ext_capability() only finds the first occurrence. This adds pci_find_next_ext_capability(), which can iterate through all of them. Signed-off-by: Bjorn Helgaas --- drivers/pci/pci.c | 40 ++++++++++++++++++++++++++++++---------- include/linux/pci.h | 1 + 2 files changed, 31 insertions(+), 10 deletions(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index f3ea977a5b1b..d34415ba0f64 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -286,20 +286,17 @@ static int pci_pcie_cap2(struct pci_dev *dev) } /** - * pci_find_ext_capability - Find an extended capability + * pci_find_next_ext_capability - Find an extended capability * @dev: PCI device to query + * @start: address at which to start looking (0 to start at beginning of list) * @cap: capability code * - * Returns the address of the requested extended capability structure + * Returns the address of the next matching extended capability structure * within the device's PCI configuration space or 0 if the device does - * not support it. Possible values for @cap: - * - * %PCI_EXT_CAP_ID_ERR Advanced Error Reporting - * %PCI_EXT_CAP_ID_VC Virtual Channel - * %PCI_EXT_CAP_ID_DSN Device Serial Number - * %PCI_EXT_CAP_ID_PWR Power Budgeting + * not support it. Some capabilities can occur several times, e.g., the + * vendor-specific capability, and this provides a way to find them all. */ -int pci_find_ext_capability(struct pci_dev *dev, int cap) +int pci_find_next_ext_capability(struct pci_dev *dev, int start, int cap) { u32 header; int ttl; @@ -311,6 +308,9 @@ int pci_find_ext_capability(struct pci_dev *dev, int cap) if (dev->cfg_size <= PCI_CFG_SPACE_SIZE) return 0; + if (start) + pos = start; + if (pci_read_config_dword(dev, pos, &header) != PCIBIOS_SUCCESSFUL) return 0; @@ -322,7 +322,7 @@ int pci_find_ext_capability(struct pci_dev *dev, int cap) return 0; while (ttl-- > 0) { - if (PCI_EXT_CAP_ID(header) == cap) + if (PCI_EXT_CAP_ID(header) == cap && pos != start) return pos; pos = PCI_EXT_CAP_NEXT(header); @@ -335,6 +335,26 @@ int pci_find_ext_capability(struct pci_dev *dev, int cap) return 0; } +EXPORT_SYMBOL_GPL(pci_find_next_ext_capability); + +/** + * pci_find_ext_capability - Find an extended capability + * @dev: PCI device to query + * @cap: capability code + * + * Returns the address of the requested extended capability structure + * within the device's PCI configuration space or 0 if the device does + * not support it. Possible values for @cap: + * + * %PCI_EXT_CAP_ID_ERR Advanced Error Reporting + * %PCI_EXT_CAP_ID_VC Virtual Channel + * %PCI_EXT_CAP_ID_DSN Device Serial Number + * %PCI_EXT_CAP_ID_PWR Power Budgeting + */ +int pci_find_ext_capability(struct pci_dev *dev, int cap) +{ + return pci_find_next_ext_capability(dev, 0, cap); +} EXPORT_SYMBOL_GPL(pci_find_ext_capability); static int __pci_find_next_ht_cap(struct pci_dev *dev, int pos, int ht_cap) diff --git a/include/linux/pci.h b/include/linux/pci.h index 5faa8310eec9..65c503cdec3b 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -755,6 +755,7 @@ enum pci_lost_interrupt_reason pci_lost_interrupt(struct pci_dev *dev); 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_dev *dev, int pos, 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); -- 2.34.1