Add function that searches for DVSEC and returns the offset in PCI configuration space for the interested DVSEC capability. Signed-off-by: Dave Jiang <dave.jiang@xxxxxxxxx> Reviewed-by: Ashok Raj <ashok.raj@xxxxxxxxx> --- The patch has dependency on David Box’s dvsec definition patch: https://lore.kernel.org/linux-pci/bc5f059c5bae957daebde699945c80808286bf45.camel@xxxxxxxxxxxxxxx/T/#m1d0dc12e3b2c739e2c37106a45f325bb8f001774 drivers/pci/pci.c | 30 ++++++++++++++++++++++++++++++ include/linux/pci.h | 3 +++ 2 files changed, 33 insertions(+) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 6d4d5a2f923d..49e57b831509 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -589,6 +589,36 @@ int pci_find_ext_capability(struct pci_dev *dev, int cap) } EXPORT_SYMBOL_GPL(pci_find_ext_capability); +/** + * pci_find_dvsec - return position of DVSEC with provided vendor and DVSEC ID + * @dev: the PCI device + * @vendor: vendor for the DVSEC + * @id: the DVSEC capibility ID + * + * Return the offset of DVSEC on success or -ENOTSUPP if not found + */ +int pci_find_dvsec(struct pci_dev *dev, u16 vendor, u16 id) +{ + u16 dev_vendor, dev_id; + int pos; + + pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DVSEC); + if (!pos) + return -ENOTSUPP; + + while (pos) { + pci_read_config_word(dev, pos + PCI_DVSEC_HEADER1, &dev_vendor); + pci_read_config_word(dev, pos + PCI_DVSEC_HEADER2, &dev_id); + if (dev_vendor == vendor && dev_id == id) + return pos; + + pos = pci_find_next_ext_capability(dev, pos, PCI_EXT_CAP_ID_DVSEC); + } + + return -ENOTSUPP; +} +EXPORT_SYMBOL_GPL(pci_find_dvsec); + /** * pci_get_dsn - Read and return the 8-byte Device Serial Number * @dev: PCI device to query diff --git a/include/linux/pci.h b/include/linux/pci.h index 22207a79762c..6c692d32c82a 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1069,6 +1069,7 @@ 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); +int pci_find_dvsec(struct pci_dev *dev, u16 vendor, u16 id); struct pci_bus *pci_find_next_bus(const struct pci_bus *from); u64 pci_get_dsn(struct pci_dev *dev); @@ -1726,6 +1727,8 @@ static inline int pci_find_next_capability(struct pci_dev *dev, u8 post, { return 0; } static inline int pci_find_ext_capability(struct pci_dev *dev, int cap) { return 0; } +static inline int pci_find_dvsec(struct pci_dev *dev, u16 vendor, u16 id) +{ return 0; } static inline u64 pci_get_dsn(struct pci_dev *dev) { return 0; }
