diff options
| -rw-r--r-- | drivers/pci/pci.c | 35 | ||||
| -rw-r--r-- | drivers/pci/pci.h | 40 |
2 files changed, 42 insertions, 33 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index ac2658d946ea..e698278229f2 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -527,42 +527,11 @@ EXPORT_SYMBOL(pci_bus_find_capability); */ u16 pci_find_next_ext_capability(struct pci_dev *dev, u16 start, int cap) { - u32 header; - int ttl; - u16 pos = PCI_CFG_SPACE_SIZE; - - /* minimum 8 bytes per capability */ - ttl = (PCI_CFG_SPACE_EXP_SIZE - PCI_CFG_SPACE_SIZE) / 8; - 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; - - /* - * If we have no capabilities, this is indicated by cap ID, - * cap version and next pointer all being 0. - */ - if (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; - - if (pci_read_config_dword(dev, pos, &header) != PCIBIOS_SUCCESSFUL) - break; - } - - return 0; + return PCI_FIND_NEXT_EXT_CAP(pci_bus_read_config, start, cap, + dev->bus, dev->devfn); } EXPORT_SYMBOL_GPL(pci_find_next_ext_capability); diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index 81580987509f..7fb44faf2c44 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -133,6 +133,46 @@ bool pcie_cap_has_rtctl(const struct pci_dev *dev); __found_pos; \ }) +/* Extended Capability finder */ +/** + * PCI_FIND_NEXT_EXT_CAP - Find a PCI extended capability + * @read_cfg: Function pointer for reading PCI config space + * @start: Starting position to begin search (0 for initial search) + * @cap: Extended capability ID to find + * @args: Arguments to pass to read_cfg function + * + * Search the extended capability list in PCI config space to find @cap. + * Implements TTL protection against infinite loops using a calculated + * maximum search count. + * + * Return: Position of the capability if found, 0 otherwise. + */ +#define PCI_FIND_NEXT_EXT_CAP(read_cfg, start, cap, args...) \ +({ \ + u16 __pos = (start) ?: PCI_CFG_SPACE_SIZE; \ + u16 __found_pos = 0; \ + int __ttl, __ret; \ + u32 __header; \ + \ + __ttl = (PCI_CFG_SPACE_EXP_SIZE - PCI_CFG_SPACE_SIZE) / 8; \ + while (__ttl-- > 0 && __pos >= PCI_CFG_SPACE_SIZE) { \ + __ret = read_cfg##_dword(args, __pos, &__header); \ + if (__ret != PCIBIOS_SUCCESSFUL) \ + break; \ + \ + if (__header == 0) \ + break; \ + \ + if (PCI_EXT_CAP_ID(__header) == (cap) && __pos != start) {\ + __found_pos = __pos; \ + break; \ + } \ + \ + __pos = PCI_EXT_CAP_NEXT(__header); \ + } \ + __found_pos; \ +}) + /* Functions internal to the PCI core code */ #ifdef CONFIG_DMI |