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authorDuncan Laurie <dlaurie@chromium.org>2014-08-11 13:38:26 -0700
committerMarc Jones <marc.jones@se-eng.com>2015-03-27 05:51:30 +0100
commit542307b8153dc773013f8be29251d9b8be8d13b8 (patch)
treebb25bb98a3dafdabea06f6613de4e20d767786cd /src/soc/intel
parent047f03ab548ba298c01cbdb1fc64cbde8e1122ce (diff)
downloadcoreboot-542307b8153dc773013f8be29251d9b8be8d13b8.tar.xz
broadwell: Add small delay before Flex Ratio reboot
In order to prevent possible TPM lockout due to PLTRST assertion shortly after powering up add a small delay before the reset. This will affect cold power up only, reboot/resume/warmboot will all have the flex ratio locked already so this reset is unneeded. BUG=chrome-os-partner:29859 BRANCH=None TEST=build and boot on samus. I tried unsuccessfully to trigger the TPM lockout, but I was not able to do that consistently without this patch so it is unknown yet whether this is 100% effective. Original-Change-Id: Ief8c9261c0268b0f90a3022213ebd2b06633b481 Original-Signed-off-by: Duncan Laurie <dlaurie@chromium.org> Original-Reviewed-on: https://chromium-review.googlesource.com/211893 Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org> (cherry picked from commit 20413f2eafa144f5f381eb6f92d8b959415ca049) Signed-off-by: Marc Jones <marc.jones@se-eng.com> Change-Id: I665e9ed1faa65e88d988660a24bdad40a4c5ab7e Reviewed-on: http://review.coreboot.org/8957 Tested-by: build bot (Jenkins) Reviewed-by: Aaron Durbin <adurbin@google.com>
Diffstat (limited to 'src/soc/intel')
-rw-r--r--src/soc/intel/broadwell/bootblock/cpu.c14
1 files changed, 14 insertions, 0 deletions
diff --git a/src/soc/intel/broadwell/bootblock/cpu.c b/src/soc/intel/broadwell/bootblock/cpu.c
index e20ced2cf6..796f884f8c 100644
--- a/src/soc/intel/broadwell/bootblock/cpu.c
+++ b/src/soc/intel/broadwell/bootblock/cpu.c
@@ -57,6 +57,17 @@ static void enable_rom_caching(void)
wrmsr(MTRRdefType_MSR, msr);
}
+static void bootblock_mdelay(int ms)
+{
+ u32 target = ms * 24 * 1000;
+ msr_t current;
+ msr_t start = rdmsr(MSR_COUNTER_24_MHZ);
+
+ do {
+ current = rdmsr(MSR_COUNTER_24_MHZ);
+ } while ((current.lo - start.lo) < target);
+}
+
static void set_flex_ratio_to_tdp_nominal(void)
{
msr_t flex_ratio, msr;
@@ -97,6 +108,9 @@ static void set_flex_ratio_to_tdp_nominal(void)
/* Set soft reset control to use register value */
RCBA32_OR(SOFT_RESET_CTRL, 1);
+ /* Delay before reset to avoid potential TPM lockout */
+ bootblock_mdelay(30);
+
/* Issue warm reset, will be "CPU only" due to soft reset data */
outb(0x0, 0xcf9);
outb(0x6, 0xcf9);