[coreboot-gerrit] New patch to review for coreboot: cpu/x86/tsc: prepare for CAR_GLOBAL in delay_tsc.c

[Aaron Durbin (adurbin@chromium.org)]

Aaron Durbin (adurbin at chromium.org) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/14300

-gerrit

commit beba79329ac43f6c820ff1ad9edea237b6c4dfe3
Author: Aaron Durbin <adurbin at chromium.org>
Date:   Fri Apr 8 21:12:01 2016 -0500

    cpu/x86/tsc: prepare for CAR_GLOBAL in delay_tsc.c
    
    The current code in delay_tsc.c uses globals and is heavily
    guarded by a lot of preprocessor macros.  In order to remove
    __PRE_RAM__ constraints one needs to use CAR_GLOBAL for the
    global variables.  Therefore, abstract away direct access to
    the globals such that CAR_GLOBAL can be easily employed.
    
    Change-Id: I3350d1a762120476926c8d9f5f5a7aba138daf5f
    Signed-off-by: Aaron Durbin <adurbin at chromium.org>
---
 src/cpu/x86/tsc/delay_tsc.c | 29 +++++++++++++++++++----------
 1 file changed, 19 insertions(+), 10 deletions(-)

diff --git a/src/cpu/x86/tsc/delay_tsc.c b/src/cpu/x86/tsc/delay_tsc.c
index 9441622..1aec472 100644
--- a/src/cpu/x86/tsc/delay_tsc.c
+++ b/src/cpu/x86/tsc/delay_tsc.c
@@ -137,32 +137,41 @@ static struct monotonic_counter {
 	int initialized;
 	struct mono_time time;
 	uint64_t last_value;
-} mono_counter;
+} mono_counter_g;
+
+static inline struct monotonic_counter *get_monotonic_context(void)
+{
+	return &mono_counter_g;
+}
 
 void timer_monotonic_get(struct mono_time *mt)
 {
 	uint64_t current_tick;
 	uint64_t ticks_elapsed;
+	unsigned long ticks_per_usec;
+	struct monotonic_counter *mono_counter;
 
-	if (!mono_counter.initialized) {
+	mono_counter = get_monotonic_context();
+	if (!mono_counter->initialized) {
 		init_timer();
-		mono_counter.last_value = rdtscll();
-		mono_counter.initialized = 1;
+		mono_counter->last_value = rdtscll();
+		mono_counter->initialized = 1;
 	}
 
 	current_tick = rdtscll();
-	ticks_elapsed = current_tick - mono_counter.last_value;
+	ticks_elapsed = current_tick - mono_counter->last_value;
+	ticks_per_usec = get_clocks_per_usec();
 
 	/* Update current time and tick values only if a full tick occurred. */
-	if (ticks_elapsed >= clocks_per_usec) {
+	if (ticks_elapsed >= ticks_per_usec) {
 		uint64_t usecs_elapsed;
 
-		usecs_elapsed = ticks_elapsed / clocks_per_usec;
-		mono_time_add_usecs(&mono_counter.time, (long)usecs_elapsed);
-		mono_counter.last_value = current_tick;
+		usecs_elapsed = ticks_elapsed / ticks_per_usec;
+		mono_time_add_usecs(&mono_counter->time, (long)usecs_elapsed);
+		mono_counter->last_value = current_tick;
 	}
 
 	/* Save result. */
-	*mt = mono_counter.time;
+	*mt = mono_counter->time;
 }
 #endif