powerpc/eeh: pseries platform config space access in EEH

With the original EEH implementation, the access to config space of
the corresponding PCI device is done by RTAS sensitive function. That
depends on pci_dn heavily. That would limit EEH extension to other
platforms like powernv because other platforms might have different
ways to access PCI config space.

The patch splits those functions used to access PCI config space
and implement them in platform related EEH component. It would be
helpful to support EEH on multiple platforms simutaneously in future.

Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/include/asm/eeh.h b/arch/powerpc/include/asm/eeh.h
index daaad91..d60f998 100644
--- a/arch/powerpc/include/asm/eeh.h
+++ b/arch/powerpc/include/asm/eeh.h
@@ -102,6 +102,8 @@
 	int (*wait_state)(struct device_node *dn, int max_wait);
 	int (*get_log)(struct device_node *dn, int severity, char *drv_log, unsigned long len);
 	int (*configure_bridge)(struct device_node *dn);
+	int (*read_config)(struct device_node *dn, int where, int size, u32 *val);
+	int (*write_config)(struct device_node *dn, int where, int size, u32 val);
 };
 
 extern struct eeh_ops *eeh_ops;