PCI: Add pci_bus_set_ops

pci_bus_set_ops changes pci_ops associated with a pci_bus. This can be
used by debug tools such as PCIE AER error injection to fake some PCI
configuration registers.

Acked-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

drivers/pci/access.c

@@ -66,6 +66,25 @@ EXPORT_SYMBOL(pci_bus_write_config_byte);
 EXPORT_SYMBOL(pci_bus_write_config_word);
 EXPORT_SYMBOL(pci_bus_write_config_dword);
 
+/**
+ * pci_bus_set_ops - Set raw operations of pci bus
+ * @bus:	pci bus struct
+ * @ops:	new raw operations
+ *
+ * Return previous raw operations
+ */
+struct pci_ops *pci_bus_set_ops(struct pci_bus *bus, struct pci_ops *ops)
+{
+	struct pci_ops *old_ops;
+	unsigned long flags;
+
+	spin_lock_irqsave(&pci_lock, flags);
+	old_ops = bus->ops;
+	bus->ops = ops;
+	spin_unlock_irqrestore(&pci_lock, flags);
+	return old_ops;
+}
+EXPORT_SYMBOL(pci_bus_set_ops);
 
 /**
  * pci_read_vpd - Read one entry from Vital Product Data

include/linux/pci.h

@@ -637,6 +637,7 @@ int pci_bus_write_config_word(struct pci_bus *bus, unsigned int devfn,
 			      int where, u16 val);
 int pci_bus_write_config_dword(struct pci_bus *bus, unsigned int devfn,
 			       int where, u32 val);
+struct pci_ops *pci_bus_set_ops(struct pci_bus *bus, struct pci_ops *ops);
 
 static inline int pci_read_config_byte(struct pci_dev *dev, int where, u8 *val)
 {