diff options
Diffstat (limited to 'drivers/pci/pci.c')
-rw-r--r-- | drivers/pci/pci.c | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 157491c..df50b48 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -526,3 +526,56 @@ int pci_find_cap(struct pci_controller *hose, pci_dev_t dev, int pos, int cap) } return 0; } + +/** + * pci_find_next_ext_capability - Find an extended capability + * + * 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. Some capabilities can occur several times, e.g., the + * vendor-specific capability, and this provides a way to find them all. + */ +int pci_find_next_ext_capability(struct pci_controller *hose, pci_dev_t dev, + int start, int cap) +{ + u32 header; + int ttl, pos = PCI_CFG_SPACE_SIZE; + + /* minimum 8 bytes per capability */ + ttl = (PCI_CFG_SPACE_EXP_SIZE - PCI_CFG_SPACE_SIZE) / 8; + + if (start) + pos = start; + + pci_hose_read_config_dword(hose, dev, pos, &header); + if (header == 0xffffffff || header == 0) + return 0; + + while (ttl-- > 0) { + if (PCI_EXT_CAP_ID(header) == cap && pos != start) + return pos; + + pos = PCI_EXT_CAP_NEXT(header); + if (pos < PCI_CFG_SPACE_SIZE) + break; + + pci_hose_read_config_dword(hose, dev, pos, &header); + if (header == 0xffffffff || header == 0) + break; + } + + return 0; +} + +/** + * pci_hose_find_ext_capability - Find an extended capability + * + * 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. + */ +int pci_hose_find_ext_capability(struct pci_controller *hose, pci_dev_t dev, + int cap) +{ + return pci_find_next_ext_capability(hose, dev, 0, cap); +} |