New patch to review for coreboot: skylake: allow timer_monotonic_get() in all stages

[Patrick Georgi]

Patrick Georgi ([e-mail]) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/11540

-gerrit

commit 37fa5de61c1751104e26eb6f7e5143ce1fd7055c
Author: Aaron Durbin 
Date:   Fri Aug 28 01:58:18 2015 -0500

skylake: allow timer_monotonic_get() in all stages

The timer_monotonic_get() function wasn't being compiled for
    romstage. To simplify the implementation don't keep track of
    partial microsecond ticks and just return the MSR value divided
    by 24 (24MHz clock).

BUG=chrome-os-partner:42115
    BRANCH=None
    TEST=Build and booted glados. Used monotonic timers in romstage
         in subsequent patches.

Change-Id: I8294c74abe09947fb4438bf5c1d0fc5265491694
    Signed-off-by: Patrick Georgi 
    Original-Commit-Id: 6d60ef204fc92c26748ab57d4ff37830cd8dc664
    Original-Change-Id: Ibdb6b9e20b9f2d48ff0f8a8c782f5c1f7ddde4f7
    Original-Signed-off-by: Aaron Durbin 
    Original-Reviewed-on: https://chromium-review.googlesource.com/295237
    Original-Reviewed-by: Duncan Laurie 
---
 src/soc/intel/skylake/Makefile.inc      |  1 +
 src/soc/intel/skylake/monotonic_timer.c | 27 ++-------------------------
 2 files changed, 3 insertions(+), 25 deletions(-)

diff --git a/src/soc/intel/skylake/Makefile.inc b/src/soc/intel/skylake/Makefile.inc
index defb945..3bd9823 100644
--- a/src/soc/intel/skylake/Makefile.inc
+++ b/src/soc/intel/skylake/Makefile.inc
@@ -13,6 +13,7 @@ subdirs-y += ../../../cpu/x86/tsc
 romstage-y += flash_controller.c
 romstage-y += gpio.c
 romstage-y += memmap.c
+romstage-y += monotonic_timer.c
 romstage-y += pch.c
 romstage-y += pcr.c
 romstage-y += pei_data.c
diff --git a/src/soc/intel/skylake/monotonic_timer.c b/src/soc/intel/skylake/monotonic_timer.c
index 35ad911..55430ef 100644
--- a/src/soc/intel/skylake/monotonic_timer.c
+++ b/src/soc/intel/skylake/monotonic_timer.c
@@ -23,12 +23,6 @@
 #include <timer.h>
 #include <soc/msr.h>

-static struct monotonic_counter {
-	int initialized;
-	struct mono_time time;
-	uint32_t last_value;
-} mono_counter;
-
 static inline uint32_t read_counter_msr(void)
 {
    /*
@@ -44,23 +38,6 @@ static inline uint32_t read_counter_msr(void)

void timer_monotonic_get(struct mono_time *mt)
 {
-	uint32_t current_tick;
-	uint32_t usecs_elapsed;
-
-	if (!mono_counter.initialized) {
-		mono_counter.last_value = read_counter_msr();
-		mono_counter.initialized = 1;
-	}
-
-	current_tick = read_counter_msr();
-	usecs_elapsed = (current_tick - mono_counter.last_value) / 24;
-
-	/* Update current time and tick values only if a full tick occurred. */
-	if (usecs_elapsed) {
-		mono_time_add_usecs(&mono_counter.time, usecs_elapsed);
-		mono_counter.last_value = current_tick;
-	}
-
-	/* Save result. */
-	*mt = mono_counter.time;
+	/* Always increases. Don't normalize to 0 between stages. */
+	mono_time_set_usecs(mt, read_counter_msr() / 24);
 }