[coreboot] [PATCH] AMD F10h: avoid timeout when waiting for AP core completion

Scott Duplichan scott at notabs.org
Mon Oct 18 17:20:33 CEST 2010

When debug logging is enabled, a message such as '* AP 02 timed out:02010501'
is sometimes logged. The reason is that the AP first sets a completion value
such as 0x13, which is what function wait_cpu_state() is waiting for. Then a
short time later, the AP calls function init_fidvid_ap(). This function sets
a completion value of 01. When logging is off, wait_cpu_state is fast enough
to see the initial completion value for each of the APs. But with logging
enabled, one or more APs may go on to complete function init_fidvid_ap, which
sets the completion value to 01. While mostly harmless, the timeout does
increase boot time. The following patch eliminates the timeout by making
function wait_cpu_state recognize 01 as an additional valid AP completion

Signed-off-by: Scott Duplichan <scott at notabs.org>

Index: src/cpu/amd/model_10xxx/init_cpus.c
--- src/cpu/amd/model_10xxx/init_cpus.c (revision 5965)
+++ src/cpu/amd/model_10xxx/init_cpus.c (working copy)
@@ -189,8 +189,10 @@
        int loop = 4000000;
        while (--loop > 0) {
                if (lapic_remote_read(apicid, LAPIC_MSG_REG, &readback) != 0)
-                       continue;
-               if ((readback & 0x3f) == state) {
+                       continue;
+               // stop polling if expected state is reached, or if
+               // init_fidvid_ap() sets 'ready for warm reset' state
+               if ((readback & 0x3f) == state || (readback & 0x3f) == 1) {
                        timeout = 0;
                        break;  //target cpu is in stage started
@@ -273,7 +275,7 @@

        /* that is from initial apicid, we need nodeid and coreid
           later */
-       id = get_node_core_id_x();
+       id = get_node_core_id_x();

        /* NB_CFG MSR is shared between cores, so we need make sure
           core0 is done at first --- use wait_all_core0_started  */

More information about the coreboot mailing list