From owner-linux-pci@atrey.karlin.mff.cuni.cz Fri Oct 28 17:42:52 2005 To: gregkh@suse.de Subject: PCI: add pci_find_next_capability() From: Roland Dreier Date: Fri, 28 Oct 2005 17:35:34 -0700 Message-ID: <52u0f1p3c9.fsf@cisco.com> Some devices have more than one capability of the same type. For example, the PCI header for the PathScale InfiniPath looks like: 04:01.0 InfiniBand: Unknown device 1fc1:000d (rev 02) Subsystem: Unknown device 1fc1:000d Flags: bus master, fast devsel, latency 0, IRQ 193 Memory at fea00000 (64-bit, non-prefetchable) [size=2M] Capabilities: [c0] HyperTransport: Slave or Primary Interface Capabilities: [f8] HyperTransport: Interrupt Discovery and Configuration There are _two_ HyperTransport capabilities, and the PathScale driver wants to look at both of them. The current pci_find_capability() API doesn't work for this, since it only allows us to get to the first capability of a given type. The patch below introduces a new pci_find_next_capability(), which can be used in a loop like for (pos = pci_find_capability(pdev, ); pos; pos = pci_find_next_capability(pdev, pos, )) { /* ... */ } Signed-off-by: Roland Dreier Signed-off-by: Matthew Wilcox Signed-off-by: Greg Kroah-Hartman drivers/pci/pci.c | 46 ++++++++++++++++++++++++++++++++-------------- include/linux/pci.h | 2 ++ 2 files changed, 34 insertions(+), 14 deletions(-) --- gregkh-2.6.orig/drivers/pci/pci.c 2005-11-02 09:26:01.000000000 -0800 +++ gregkh-2.6/drivers/pci/pci.c 2005-11-02 10:35:48.000000000 -0800 @@ -63,11 +63,38 @@ return max; } +static int __pci_find_next_cap(struct pci_bus *bus, unsigned int devfn, u8 pos, int cap) +{ + u8 id; + int ttl = 48; + + while (ttl--) { + pci_bus_read_config_byte(bus, devfn, pos, &pos); + if (pos < 0x40) + break; + pos &= ~3; + pci_bus_read_config_byte(bus, devfn, pos + PCI_CAP_LIST_ID, + &id); + if (id == 0xff) + break; + if (id == cap) + return pos; + pos += PCI_CAP_LIST_NEXT; + } + return 0; +} + +int pci_find_next_capability(struct pci_dev *dev, u8 pos, int cap) +{ + return __pci_find_next_cap(dev->bus, dev->devfn, + pos + PCI_CAP_LIST_NEXT, cap); +} +EXPORT_SYMBOL_GPL(pci_find_next_capability); + static int __pci_bus_find_cap(struct pci_bus *bus, unsigned int devfn, u8 hdr_type, int cap) { u16 status; - u8 pos, id; - int ttl = 48; + u8 pos; pci_bus_read_config_word(bus, devfn, PCI_STATUS, &status); if (!(status & PCI_STATUS_CAP_LIST)) @@ -76,24 +103,15 @@ switch (hdr_type) { case PCI_HEADER_TYPE_NORMAL: case PCI_HEADER_TYPE_BRIDGE: - pci_bus_read_config_byte(bus, devfn, PCI_CAPABILITY_LIST, &pos); + pos = PCI_CAPABILITY_LIST; break; case PCI_HEADER_TYPE_CARDBUS: - pci_bus_read_config_byte(bus, devfn, PCI_CB_CAPABILITY_LIST, &pos); + pos = PCI_CB_CAPABILITY_LIST; break; default: return 0; } - while (ttl-- && pos >= 0x40) { - pos &= ~3; - pci_bus_read_config_byte(bus, devfn, pos + PCI_CAP_LIST_ID, &id); - if (id == 0xff) - break; - if (id == cap) - return pos; - pci_bus_read_config_byte(bus, devfn, pos + PCI_CAP_LIST_NEXT, &pos); - } - return 0; + return __pci_find_next_cap(bus, devfn, pos, cap); } /** --- gregkh-2.6.orig/include/linux/pci.h 2005-11-02 09:25:08.000000000 -0800 +++ gregkh-2.6/include/linux/pci.h 2005-11-02 10:35:48.000000000 -0800 @@ -338,6 +338,7 @@ struct pci_dev *pci_find_device_reverse (unsigned int vendor, unsigned int device, const struct pci_dev *from); struct pci_dev *pci_find_slot (unsigned int bus, unsigned int devfn); 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); struct pci_bus * pci_find_next_bus(const struct pci_bus *from); @@ -550,6 +551,7 @@ static inline int pci_register_driver(struct pci_driver *drv) { return 0;} static inline void pci_unregister_driver(struct pci_driver *drv) { } static inline int pci_find_capability (struct pci_dev *dev, int cap) {return 0; } +static inline int pci_find_next_capability (struct pci_dev *dev, u8 post, int cap) { return 0; } static inline int pci_find_ext_capability (struct pci_dev *dev, int cap) {return 0; } static inline const struct pci_device_id *pci_match_device(const struct pci_device_id *ids, const struct pci_dev *dev) { return NULL; }