powerpc/eeh: EEH post initialization operation

The patch adds new EEH operation post_init. It's used to notify
the platform that EEH core has completed the EEH probe. By that,
PowerNV platform starts to use the services supplied by EEH
functionality.

Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/include/asm/eeh.h

@@ -131,6 +131,7 @@ static inline struct pci_dev *eeh_dev_to_pci_dev(struct eeh_dev *edev)
 struct eeh_ops {
 	char *name;
 	int (*init)(void);
+	int (*post_init)(void);
 	void* (*of_probe)(struct device_node *dn, void *flag);
 	int (*dev_probe)(struct pci_dev *dev, void *flag);
 	int (*set_option)(struct eeh_pe *pe, int option);

arch/powerpc/kernel/eeh.c

@@ -720,6 +720,17 @@ int __init eeh_init(void)
 		return -EINVAL;
 	}
 
+	/*
+	 * Call platform post-initialization. Actually, It's good chance
+	 * to inform platform that EEH is ready to supply service if the
+	 * I/O cache stuff has been built up.
+	 */
+	if (eeh_ops->post_init) {
+		ret = eeh_ops->post_init();
+		if (ret)
+			return ret;
+	}
+
 	if (eeh_subsystem_enabled)
 		pr_info("EEH: PCI Enhanced I/O Error Handling Enabled\n");
 	else