From 44a9a36f6be43636ac2342c06d9feb60db77826a Mon Sep 17 00:00:00 2001 From: Bjorn Helgaas Date: Fri, 13 Jul 2012 14:24:59 -0600 Subject: [PATCH 1/2] 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 | 86 ++++++++++++++++++++++++++++----------------- include/linux/pci.h | 1 + 2 files changed, 54 insertions(+), 33 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 @@ -285,6 +285,58 @@ static int pci_pcie_cap2(struct pci_dev *dev) return pos; } +/** + * 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 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_dev *dev, int start, int cap) +{ + u32 header; + int ttl; + int 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; +} +EXPORT_SYMBOL_GPL(pci_find_next_ext_capability); + /** * pci_find_ext_capability - Find an extended capability * @dev: PCI device to query @@ -301,39 +353,7 @@ static int pci_pcie_cap2(struct pci_dev *dev) */ int pci_find_ext_capability(struct pci_dev *dev, int cap) { - u32 header; - int ttl; - int 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 (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) - 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_capability(dev, 0, cap); } EXPORT_SYMBOL_GPL(pci_find_ext_capability); 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); From defb9446fe417f72855bc8bf97aa5d8af076bdf8 Mon Sep 17 00:00:00 2001 From: Bjorn Helgaas Date: Fri, 13 Jul 2012 14:30:21 -0600 Subject: [PATCH 2/2] PCI: Add Vendor-Specific Extended Capability header info This adds the fields in the Vendor-Specific Header: ID, Rev, and Length. There may be multiple Vendor-Specific capabilities, so drivers should use the VSEC ID to identify the one of interest. Signed-off-by: Bjorn Helgaas --- include/linux/pci_regs.h | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/include/linux/pci_regs.h b/include/linux/pci_regs.h index 7fb75b143755..02448b1a0902 100644 --- a/include/linux/pci_regs.h +++ b/include/linux/pci_regs.h @@ -677,6 +677,12 @@ #define PCI_PWR_CAP_BUDGET(x) ((x) & 1) /* Included in system budget */ #define PCI_EXT_CAP_PWR_SIZEOF 16 +/* Vendor-Specific (VSEC, PCI_EXT_CAP_ID_VNDR) */ +#define PCI_VNDR_HEADER 4 /* Vendor-Specific Header */ +#define PCI_VNDR_HEADER_ID(x) ((x) & 0xffff) +#define PCI_VNDR_HEADER_REV(x) (((x) >> 16) & 0xf) +#define PCI_VNDR_HEADER_LEN(x) (((x) >> 20) & 0xfff) + /* * Hypertransport sub capability types *