sio: Add test for availability - LPC error tweak

Some components can continue to operate in the face of the SuperIO
controller being unavailable on the LPC bus (specifically, the UART and
boot flag processing). Other components require it present (AST-based
SFC implementations and the AST mailbox). Components in the latter
category can just fail with an errl when they attempt to access the
controller, but for those in the former category we add an isAvailable()
function in the SIO namespace to sidestep dealing with errors.

Specifically, isAvailable() tests for the expected error when the
SuperIO controller is disabled, and returns an errlHndl_t if any other
error occurs. This way true LPC errors are propagated to the caller to
commit as desired.

Change-Id: Ib94ceabfd4f4e9c63c114cfe3db3c954dbb6d6e5
Reviewed-on: http://rchgit01.rchland.ibm.com/gerrit1/67315
Tested-by: Jenkins Server <pfd-jenkins+hostboot@us.ibm.com>
Reviewed-by: ANDREW R. JEFFERY <andrewrj@au1.ibm.com>
Tested-by: Jenkins OP Build CI <op-jenkins+hostboot@us.ibm.com>
Tested-by: Jenkins OP HW <op-hw-jenkins+hostboot@us.ibm.com>
Tested-by: FSP CI Jenkins <fsp-CI-jenkins+hostboot@us.ibm.com>
Reviewed-by: Corey V. Swenson <cswenson@us.ibm.com>
Reviewed-by: William G. Hoffa <wghoffa@us.ibm.com>

2 files changed, 16 insertions, 1 deletions

diff --git a/src/include/usr/lpc/lpc_reasoncodes.H b/src/include/usr/lpc/lpc_reasoncodes.H
index d5c15628a..ed2de4bfb 100644
--- a/src/include/usr/lpc/lpc_reasoncodes.H
+++ b/src/include/usr/lpc/lpc_reasoncodes.H
@@ -5,7 +5,7 @@
 /*                                                                        */
 /* OpenPOWER HostBoot Project                                             */
 /*                                                                        */
-/* Contributors Listed Below - COPYRIGHT 2014,2017                        */
+/* Contributors Listed Below - COPYRIGHT 2014,2018                        */
 /* [+] Google Inc.                                                        */
 /* [+] International Business Machines Corp.                              */
 /*                                                                        */
@@ -55,6 +55,7 @@ namespace LPC
         RC_CANT_USE_SENTINEL         = LPC_COMP_ID | 0x08,
         RC_BAD_TARGET                = LPC_COMP_ID | 0x09,
         RC_LPCHC_ERROR               = LPC_COMP_ID | 0x0A,
+        RC_LPCHC_SYNCAB_ERROR        = LPC_COMP_ID | 0x0B,
     };
 };
 
diff --git a/src/include/usr/sio/sio.H b/src/include/usr/sio/sio.H
index 52f752da7..ec422d8b7 100644
--- a/src/include/usr/sio/sio.H
+++ b/src/include/usr/sio/sio.H
@@ -25,6 +25,8 @@
 #ifndef __SIO_SIO_H
 #define __SIO_SIO_H
 
+#include <errl/errlentry.H>
+
 namespace SIO
 {
     /**
@@ -47,5 +49,17 @@ namespace SIO
         SIO_SCRATCH_REG1        = 0x21,     /**< Scratch Reg */
         SIO_SCRATCH_REG2        = 0x22,     /**< Scratch Reg */
     };
+
+    /**
+     * @brief Test if SuperIO is accessible on the LPC bus
+     *
+     * @param[out] o_available Set true if the SuperIO controller is available,
+     *                         false if it explicitly detected as unavailable,
+     *                         and unchanged if an unexpected error occurs.
+     *
+     * @return NULL if the test did not fail unexpectedly, otherwise a pointer
+     *         to an errorlog associated with the error.
+     */
+    errlHndl_t isAvailable(bool& o_available);
 }
 #endif