From patchwork Mon Oct 18 16:38:55 2010
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Subject: faster AP launch for recent AMD processors
Date: Mon, 18 Oct 2010 16:38:55 -0000
From: Scott <scott@notabs.org>
X-Patchwork-Id: 2137
Message-Id: <133458B4C40B45598D9C8042D34DAE4F@m3a78>
To: <coreboot@coreboot.org>

To reduce boot time, removing the double startup IPI and 10 ms
delay from lapic_cpu_init.c should be considered. Because I can
test this code only on recent AMD cpu models, it is only safe
to apply the change in those cases. The following patch uses
a compile time check to identify CPUs where the change is known
to work. Would a runtime check be better?

Thanks,
Scott

Signed-off-by: Scott Duplichan <scott@notabs.org>
Acked-by: Myles Watson <mylesgw@gmail.com>


Index: src/cpu/x86/lapic/lapic_cpu_init.c
===================================================================
--- src/cpu/x86/lapic/lapic_cpu_init.c  (revision 5965)
+++ src/cpu/x86/lapic/lapic_cpu_init.c  (working copy)
@@ -113,7 +113,9 @@
                }
                return 0;
        }
+   #if !defined (CONFIG_CPU_AMD_MODEL_10XXX) && !defined (CONFIG_CPU_AMD_MODEL_14XXX)
        mdelay(10);
+   #endif

        printk(BIOS_SPEW, "Deasserting INIT.\n");

@@ -144,6 +146,9 @@
 #endif

        num_starts = 2;
+   #if defined (CONFIG_CPU_AMD_MODEL_10XXX) || defined (CONFIG_CPU_AMD_MODEL_14XXX)
+       num_starts = 1;
+       #endif

        /*
         * Run STARTUP IPI loop.