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authorJesse Barnes <jbarnes@virtuousgeek.org>2009-07-15 13:13:00 -0700
committerH. Peter Anvin <hpa@zytor.com>2010-02-19 16:12:26 -0800
commitcf4c43dd439b90a1a876b3f836ebe745abb9a269 (patch)
tree59d7a278d9d5cb6c9927819fa75231e284b29556 /drivers/pci
parent724e6d3fe8003c3f60bf404bf22e4e331327c596 (diff)
downloadop-kernel-dev-cf4c43dd439b90a1a876b3f836ebe745abb9a269.zip
op-kernel-dev-cf4c43dd439b90a1a876b3f836ebe745abb9a269.tar.gz
PCI: Add pci_bus_find_ext_capability
For use by code that needs to walk extended capability lists before pci_dev structures are set up. Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org> LKML-Reference: <43F901BD926A4E43B106BF17856F07559FB80CFD@orsmsx508.amr.corp.intel.com> Signed-off-by: Jacob Pan <jacob.jun.pan@intel.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'drivers/pci')
-rw-r--r--drivers/pci/pci.c43
1 files changed, 43 insertions, 0 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 315fea4..aad62af 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -297,6 +297,49 @@ int pci_find_ext_capability(struct pci_dev *dev, int cap)
}
EXPORT_SYMBOL_GPL(pci_find_ext_capability);
+/**
+ * pci_bus_find_ext_capability - find an extended capability
+ * @bus: the PCI bus to query
+ * @devfn: PCI device to query
+ * @cap: capability code
+ *
+ * Like pci_find_ext_capability() but works for pci devices that do not have a
+ * pci_dev structure set up yet.
+ *
+ * Returns the address of the requested capability structure within the
+ * device's PCI configuration space or 0 in case the device does not
+ * support it.
+ */
+int pci_bus_find_ext_capability(struct pci_bus *bus, unsigned int devfn,
+ 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 (!pci_bus_read_config_dword(bus, devfn, pos, &header))
+ return 0;
+ if (header == 0xffffffff || 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_bus_read_config_dword(bus, devfn, pos, &header))
+ break;
+ }
+
+ return 0;
+}
+
static int __pci_find_next_ht_cap(struct pci_dev *dev, int pos, int ht_cap)
{
int rc, ttl = PCI_FIND_CAP_TTL;
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