Some extended capabilities, e.g., the vendor-specific capability, can
occur several times. The existing pci_find_ext_capability() always finds
the first occurrence. This adds pci_find_next_ext_capability(), which can
iterate through all of them.
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
---
drivers/pci/pci.c | 40 ++++++++++++++++++++++++++++++----------
include/linux/pci.h | 3 +--
2 files changed, 31 insertions(+), 12 deletions(-)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 447e834..fa0aa94 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -278,20 +278,17 @@ int pci_bus_find_capability(struct pci_bus *bus, unsigned int devfn, int cap)
}
/**
- * pci_find_ext_capability - Find an extended capability
+ * 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 requested extended capability structure
+ * 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. Possible values for @cap:
- *
- * %PCI_EXT_CAP_ID_ERR Advanced Error Reporting
- * %PCI_EXT_CAP_ID_VC Virtual Channel
- * %PCI_EXT_CAP_ID_DSN Device Serial Number
- * %PCI_EXT_CAP_ID_PWR Power Budgeting
+ * 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_ext_capability(struct pci_dev *dev, int cap)
+int pci_find_next_ext_capability(struct pci_dev *dev, int start, int cap)
{
u32 header;
int ttl;
@@ -303,6 +300,9 @@ int pci_find_ext_capability(struct pci_dev *dev, int cap)
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;
@@ -314,7 +314,7 @@ int pci_find_ext_capability(struct pci_dev *dev, int cap)
return 0;
while (ttl-- > 0) {
- if (PCI_EXT_CAP_ID(header) == cap)
+ if (PCI_EXT_CAP_ID(header) == cap && pos != start)
return pos;
pos = PCI_EXT_CAP_NEXT(header);
@@ -327,6 +327,26 @@ int pci_find_ext_capability(struct pci_dev *dev, int cap)
return 0;
}
+EXPORT_SYMBOL_GPL(pci_find_next_ext_capability);
+
+/**
+ * pci_find_ext_capability - Find an extended capability
+ * @dev: PCI device to query
+ * @cap: capability code
+ *
+ * Returns the address of the requested extended capability structure
+ * within the device's PCI configuration space or 0 if the device does
+ * not support it. Possible values for @cap:
+ *
+ * %PCI_EXT_CAP_ID_ERR Advanced Error Reporting
+ * %PCI_EXT_CAP_ID_VC Virtual Channel
+ * %PCI_EXT_CAP_ID_DSN Device Serial Number
+ * %PCI_EXT_CAP_ID_PWR Power Budgeting
+ */
+int pci_find_ext_capability(struct pci_dev *dev, int cap)
+{
+ 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 d8c379d..39d2fe0 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -714,8 +714,7 @@ 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_bus_find_ext_capability(struct pci_bus *bus, unsigned int devfn,
- 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);
--
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