Sometimes we need to find PCI EXT CAP before
pci_dev set up. So introduce pci_bus_find_ext_capability(),
it will be used to get PCI EXT DSN before pci_dev set up.
Signed-off-by: Yijing Wang <wangyijing@xxxxxxxxxx>
---
drivers/pci/pci.c | 32 ++++++++++++++++++++++++++++++++
include/linux/pci.h | 1 +
2 files changed, 33 insertions(+), 0 deletions(-)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index a263c0a..4502e6f 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -327,6 +327,38 @@ 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, int devfn, int cap)
+{
+ int pos;
+ u32 status;
+
+ pos = pci_bus_find_capability(bus, devfn, PCI_CAP_ID_EXP);
+ if (!pos)
+ return 0;
+
+ if (pci_bus_read_config_dword(bus, devfn, PCI_CFG_SPACE_SIZE,
+ &status) !=
+ PCIBIOS_SUCCESSFUL || status == 0xffffffff)
+ return 0;
+
+ return pci_find_next_ext_capability(bus, devfn, 0, cap);
+}
+
+
static int __pci_find_next_ht_cap(struct pci_dev *dev, int pos, int ht_cap)
{
int rc, ttl = PCI_FIND_CAP_TTL;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index df495e9..470de02 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -797,6 +797,7 @@ 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_bus *bus, int devfn, int pos, int cap);
+int pci_bus_find_ext_capability(struct pci_bus *bus, int devfn, 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);
--
1.7.1
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