Add pci_find_vsec_capability() that crawls through the device config space searching in all Vendor-Specific Extended Capabilities for a particular capability ID.
Vendor-Specific Extended Capability (VSEC) is a PCIe capability (acts like a wrapper) specified by PCI-SIG that allows the vendor to create their own and specific capability in the device config space. Signed-off-by: Gustavo Pimentel <[email protected]> --- drivers/pci/pci.c | 29 +++++++++++++++++++++++++++++ include/linux/pci.h | 1 + include/uapi/linux/pci_regs.h | 5 +++++ 3 files changed, 35 insertions(+) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 6d4d5a2..235d0b2 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -623,6 +623,35 @@ u64 pci_get_dsn(struct pci_dev *dev) } EXPORT_SYMBOL_GPL(pci_get_dsn); +/** + * pci_find_vsec_capability - Find a vendor-specific extended capability + * @dev: PCI device to query + * @cap: vendor-specific capability id code + * + * Returns the address of the vendor-specific structure that matches the + * requested capability id code within the device's PCI configuration space + * or 0 if it does not find a match. + */ +int pci_find_vsec_capability(struct pci_dev *dev, int vsec_cap_id) +{ + u32 header; + int vsec; + + vsec = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_VNDR); + while (vsec) { + if (pci_read_config_dword(dev, vsec + 0x4, + &header) == PCIBIOS_SUCCESSFUL && + PCI_VSEC_CAP_ID(header) == vsec_cap_id) + break; + + vsec = pci_find_next_ext_capability(dev, vsec, + PCI_EXT_CAP_ID_VNDR); + } + + return vsec; +} +EXPORT_SYMBOL_GPL(pci_find_vsec_capability); + 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 22207a7..effecb0 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1067,6 +1067,7 @@ 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_dev *dev, int pos, int cap); +int pci_find_vsec_capability(struct pci_dev *dev, int vsec_cap_id); 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); diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h index a95d55f..f5d17be 100644 --- a/include/uapi/linux/pci_regs.h +++ b/include/uapi/linux/pci_regs.h @@ -730,6 +730,11 @@ #define PCI_EXT_CAP_DSN_SIZEOF 12 #define PCI_EXT_CAP_MCAST_ENDPOINT_SIZEOF 40 +/* Vendor-Specific Extended Capabilities */ +#define PCI_VSEC_CAP_ID(header) (header & 0x0000ffff) +#define PCI_VSEC_CAP_REV(header) ((header >> 16) & 0xf) +#define PCI_VSEC_CAP_LEN(header) ((header >> 20) & 0xffc) + /* Advanced Error Reporting */ #define PCI_ERR_UNCOR_STATUS 4 /* Uncorrectable Error Status */ #define PCI_ERR_UNC_UND 0x00000001 /* Undefined */ -- 2.7.4
