sio: Add test for availability

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.

For the moment *all* errors produced by the SIO::isAvailable() LPC bus
access will result in the SIO code assuming the device is absent. We
should be more precise about this, but the hardware behaviour seen under
hostboot currently prevents us from being more specific. This problem is
highlighted by a FIXME block in the implementation of
SIO::isAvailable().

Change-Id: Id30a09b48586d2054e0cdae625ee23df68ac2aa3
Signed-off-by: Andrew Jeffery <andrewrj@au1.ibm.com>
Reviewed-on: http://rchgit01.rchland.ibm.com/gerrit1/67460
Tested-by: Jenkins Server <pfd-jenkins+hostboot@us.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: Daniel M. Crowell <dcrowell@us.ibm.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/src/usr/initservice/bootconfig/bootconfig_ast2400.C b/src/usr/initservice/bootconfig/bootconfig_ast2400.C
index c7e0a3d8b..87caa32a5 100644
--- a/src/usr/initservice/bootconfig/bootconfig_ast2400.C
+++ b/src/usr/initservice/bootconfig/bootconfig_ast2400.C
@@ -212,6 +212,21 @@ errlHndl_t AST2400BootConfig::readAndProcessBootConfig()
     size_t l_len = sizeof(uint8_t);
     do
     {
+        // The BMC may have disabled SIO, in which case we use a default set of
+        // boot flags
+        bool haveSio;
+        l_err = SIO::isAvailable(haveSio);
+        if (l_err)
+        {
+            break;
+        }
+
+        if (!haveSio)
+        {
+            processBootFlagsV1(0);
+            break;
+        }
+
         // read the register holding the agreed upon magic
         // number to indicate registers have been configured