powerpc/eeh: Debugfs for error injection

The patch creates debugfs entries (powerpc/PCIxxxx/err_injct) for
injecting EEH errors for testing purpose.
Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/platforms/powernv/eeh-ioda.c

@@ -12,6 +12,7 @@
  */
 
 #include <linux/bootmem.h>
+#include <linux/debugfs.h>
 #include <linux/delay.h>
 #include <linux/init.h>
 #include <linux/io.h>
@@ -64,6 +65,29 @@ static struct notifier_block ioda_eeh_nb = {
 	.priority	= 0
 };
 
+#ifdef CONFIG_DEBUG_FS
+static int ioda_eeh_dbgfs_set(void *data, u64 val)
+{
+	struct pci_controller *hose = data;
+	struct pnv_phb *phb = hose->private_data;
+
+	out_be64(phb->regs + 0xD10, val);
+	return 0;
+}
+
+static int ioda_eeh_dbgfs_get(void *data, u64 *val)
+{
+	struct pci_controller *hose = data;
+	struct pnv_phb *phb = hose->private_data;
+
+	*val = in_be64(phb->regs + 0xD10);
+	return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(ioda_eeh_dbgfs_ops, ioda_eeh_dbgfs_get,
+			ioda_eeh_dbgfs_set, "0x%llx\n");
+#endif /* CONFIG_DEBUG_FS */
+
 /**
  * ioda_eeh_post_init - Chip dependent post initialization
  * @hose: PCI controller
@@ -101,6 +125,13 @@ static int ioda_eeh_post_init(struct pci_controller *hose)
 			}
 		}
 
+#ifdef CONFIG_DEBUG_FS
+		if (phb->dbgfs)
+			debugfs_create_file("err_injct", 0600,
+					    phb->dbgfs, hose,
+					    &ioda_eeh_dbgfs_ops);
+#endif
+
 		phb->eeh_enabled = 1;
 	}