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>

3 files changed, 16 insertions, 1 deletions

diff --git a/src/usr/pnor/ast_mboxdd.C b/src/usr/pnor/ast_mboxdd.C
index b7504e934..5b6e58300 100644
--- a/src/usr/pnor/ast_mboxdd.C
+++ b/src/usr/pnor/ast_mboxdd.C
@@ -365,6 +365,11 @@ errlHndl_t astMbox::initializeMbox(void)
 
     do
     {
+        // The BMC may have disabled SIO access, but there's not much point in
+        // testing whether it's available as there's no alternative action if
+        // it is not. Instead, just try the SIO accesses and bail out with the
+        // errl if they fail.
+
         //First disable SIO Mailbox engine to configure it
         // 0x30 - Enable/Disable Reg
         l_data = SIO::DISABLE_DEVICE;
diff --git a/src/usr/pnor/sfc_ast2400.C b/src/usr/pnor/sfc_ast2400.C
index e8e612efa..aa0e2bb07 100644
--- a/src/usr/pnor/sfc_ast2400.C
+++ b/src/usr/pnor/sfc_ast2400.C
@@ -5,7 +5,7 @@
 /*                                                                        */
 /* OpenPOWER HostBoot Project                                             */
 /*                                                                        */
-/* Contributors Listed Below - COPYRIGHT 2014,2016                        */
+/* Contributors Listed Below - COPYRIGHT 2014,2018                        */
 /* [+] Google Inc.                                                        */
 /* [+] International Business Machines Corp.                              */
 /*                                                                        */
@@ -95,6 +95,11 @@ errlHndl_t SfcAST2400::hwInit( )
     uint32_t l_lpc_addr;
     do
     {
+        // The BMC may have disabled SIO access, but there's not much point in
+        // testing whether it's available as there's no alternative action if
+        // it is not. Instead, just try the SIO accesses and bail out with the
+        // errl if they fail.
+
         /* Enable device 0x0D*/
         uint8_t l_data = SIO::ENABLE_DEVICE;
         size_t l_len = sizeof(l_data);
diff --git a/src/usr/pnor/sfc_ast2500.C b/src/usr/pnor/sfc_ast2500.C
index 39465f9b2..9f4d88ae1 100644
--- a/src/usr/pnor/sfc_ast2500.C
+++ b/src/usr/pnor/sfc_ast2500.C
@@ -94,6 +94,11 @@ errlHndl_t SfcAST2500::hwInit( )
     uint32_t l_lpc_addr;
     do
     {
+        // The BMC may have disabled SIO access, but there's not much point in
+        // testing whether it's available as there's no alternative action if
+        // it is not. Instead, just try the SIO accesses and bail out with the
+        // errl if they fail.
+
         /* Enable device 0x0D*/
         uint8_t l_data = SIO::ENABLE_DEVICE;
         size_t l_len = sizeof(l_data);