powerpc/eeh: Allow disabling recovery

Currently when we detect an error we automatically invoke the EEH recovery
handler. This can be annoying when debugging EEH problems, or when working
on EEH itself so this patch adds a debugfs knob that will prevent a
recovery event from being queued up when an issue is detected.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/kernel/eeh.c

@@ -111,6 +111,13 @@ EXPORT_SYMBOL(eeh_subsystem_flags);
  */
 u32 eeh_max_freezes = 5;
 
+/*
+ * Controls whether a recovery event should be scheduled when an
+ * isolated device is discovered. This is only really useful for
+ * debugging problems with the EEH core.
+ */
+bool eeh_debugfs_no_recover;
+
 /* Platform dependent EEH operations */
 struct eeh_ops *eeh_ops = NULL;
 
@@ -1843,6 +1850,9 @@ static int __init eeh_init_proc(void)
 					   &eeh_enable_dbgfs_ops);
 		debugfs_create_u32("eeh_max_freezes", 0600,
 				powerpc_debugfs_root, &eeh_max_freezes);
+		debugfs_create_bool("eeh_disable_recovery", 0600,
+				powerpc_debugfs_root,
+				&eeh_debugfs_no_recover);
 		eeh_cache_debugfs_init();
 #endif
 	}