1 files changed, 64 insertions, 21 deletions

diff --git a/src/usr/sio/siodd.C b/src/usr/sio/siodd.C
index 5301d9e1c..8bbc59f5b 100755
--- a/src/usr/sio/siodd.C
+++ b/src/usr/sio/siodd.C
@@ -37,6 +37,9 @@
 #include <hbotcompid.H>
 #include <stdarg.h>
 #include <targeting/common/target.H>
+#include <lpc/lpc_reasoncodes.H>
+
+#include <console/consoleif.H>
 
 // Trace definition
 trace_desc_t* g_trac_sio = NULL;
@@ -191,32 +194,64 @@ DEVICE_REGISTER_ROUTE( DeviceFW::WRITE,
                        TARGETING::TYPE_PROC,
                        ahbSioWriteDD );
 
-//function to unlock superIO password register
-void SioDD::unlock_SIO(TARGETING::Target* i_target)
+errlHndl_t SIO::isAvailable(bool& available)
 {
     uint8_t l_byte = SIO::SIO_PASSWORD_REG;
-    errlHndl_t l_err = NULL;
-    do
-    {
-        // Unlock the SIO registers
-        //  (write 0xA5 password to offset 0x2E two times)
     size_t l_len = sizeof(uint8_t);
-    l_err = deviceWrite(i_target,
-                        &l_byte,
-                        l_len,
-                        DEVICE_LPC_ADDRESS(LPC::TRANS_IO, SIO::SIO_ADDR_REG_2E));
-    if(l_err) { break; }
-    l_err = deviceWrite(i_target,
-                        &l_byte,
-                        l_len,
+    errlHndl_t l_err = NULL;
+
+    l_err = deviceWrite(TARGETING::MASTER_PROCESSOR_CHIP_TARGET_SENTINEL,
+                        &l_byte, l_len,
                         DEVICE_LPC_ADDRESS(LPC::TRANS_IO, SIO::SIO_ADDR_REG_2E));
-    } while(0);
 
     if (l_err)
     {
-        TRACFCOMP(g_trac_sio,"Error in unlocking SIO password register\n");
-        errlCommit(l_err, SIO_COMP_ID);
+        /* FIXME: The implementation assumes that any error indicates that the
+         * SIO device is not available. This, generally, is a terribe
+         * assumption. We should instead look for the specific failure, which
+         * is a LPC SYNC No Response (and this is what we see in skiboot).
+         * Currently there are open questions about the hardware behaviour as
+         * observed by hostboot: We see an OPBM Error Acknowledge state when we
+         * try to access an absent SIO device, but no error state is present in
+         * the LPCHC status register.
+         *
+         * We retain the interface of returning an errlHndl_t to future-proof
+         * the code. The caller should commit the errl if it is valid.
+         */
+        TRACFCOMP(g_trac_sio,
+                  "Received error during SIO availability test, assuming "
+                  "absent. Reason code: 0x%x, user data: [0x%8x, 0x%8x]",
+                  l_err->reasonCode(), l_err->getUserData1(),
+                  l_err->getUserData2());
+        available = false;
+        delete l_err;
+        l_err = NULL;
+    }
+    else
+    {
+        available = true;
     }
+
+    return l_err;
+}
+
+//function to unlock superIO password register
+errlHndl_t SioDD::unlock_SIO(TARGETING::Target* i_target)
+{
+    uint8_t l_byte = SIO::SIO_PASSWORD_REG;
+    size_t l_len = sizeof(uint8_t);
+    errlHndl_t l_err = NULL;
+    int again = 1;
+
+    do
+    {
+    // Unlock the SIO registers (write 0xA5 password to offset 0x2E two times)
+    l_err = deviceWrite(i_target, &l_byte, l_len,
+                        DEVICE_LPC_ADDRESS(LPC::TRANS_IO,
+                                           SIO::SIO_ADDR_REG_2E));
+    } while(!l_err && again--);
+
+    return l_err;
 }
 
 //SioDD constructor
@@ -225,7 +260,16 @@ SioDD::SioDD(TARGETING::Target* i_target)
     assert(i_target == TARGETING::MASTER_PROCESSOR_CHIP_TARGET_SENTINEL);
     mutex_init(&iv_sio_mutex);
     iv_prev_dev = 0x00;
-    unlock_SIO(i_target);
+
+    errlHndl_t err = unlock_SIO(i_target);
+    bool failed = (err != NULL);
+    delete err;
+
+    /* Unlocked very early, so make some noise if we fail */
+    if (failed)
+    {
+        printk("SuperIO unlock failed! Expect future errors\n");
+    }
 }
 
 //SioDD destructor
@@ -279,8 +323,7 @@ errlHndl_t SioDD::_readSIO(TARGETING::Target* i_target,
 //function to change logical device in SIO
 errlHndl_t SioDD::changeDevice(TARGETING::Target* i_target, uint8_t i_dev)
 {
-    uint8_t l_reg = SIO::SIO_DEVICE_SELECT_REG;
-    return _writeSIO(i_target, l_reg, &i_dev);
+    return _writeSIO(i_target, SIO::SIO_DEVICE_SELECT_REG, &i_dev);
 }
 
 //function to read from SIO register