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exynos5250: monotonic timer implementation (using MCT) 

This implements the new monotonic timer API using the global
multi-core timer (MCT).

Change-Id: Id56249ff5d3e0f85808f5754954c83c0bc75f1c1
Signed-off-by: David Hendricks <dhendrix@chromium.org>
Reviewed-on: http://review.coreboot.org/3175
Reviewed-by: Aaron Durbin <adurbin@google.com>
Tested-by: build bot (Jenkins)
This commit is contained in:
David Hendricks 2013-05-02 13:23:08 -07:00 committed by Stefan Reinauer
parent 008616247d
commit 5ec69ed884
3 changed files with 62 additions and 3 deletions
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2
src/cpu/samsung/exynos5250/clk.h
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@ -585,4 +585,6 @@ int clock_get_mem_selection(enum ddr_mode *mem_type,
unsigned *frequency_mhz, unsigned *arm_freq,
enum mem_manuf *mem_manuf);
uint64_t mct_raw_value(void);
#endif

5
src/cpu/samsung/exynos5250/mct.c
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@ -88,7 +88,7 @@ static int enabled = 0;
static struct mct_regs *const mct =
(struct mct_regs *)MCT_ADDRESS;
static uint64_t timer_raw_value(void)
uint64_t mct_raw_value(void)
{
if (!enabled) {
writel(readl(&mct->g_tcon) | (0x1 << 8), &mct->g_tcon);
@ -109,9 +109,8 @@ void timer_start(void)
u32 timer_us(void)
{
uint64_t raw = timer_raw_value();
uint64_t raw = mct_raw_value();
static uint32_t ticks_per_microsecond = MCT_HZ/1000000;
uint32_t usec = raw / ticks_per_microsecond;
return usec;
}

58
src/cpu/samsung/exynos5250/monotonic_timer.c Normal file
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@ -0,0 +1,58 @@
/*
* This file is part of the coreboot project.
*
* Copyright (C) 2013 Google, Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <stdint.h>
#include <delay.h>
#include <timer.h>
#include <time.h> /* TODO: deprecate in favor of monotonic timer stuff */
#include "clk.h"
static struct monotonic_counter {
int initialized;
struct mono_time time;
uint64_t last_value;
} mono_counter;
static const uint32_t clocks_per_usec = MCT_HZ/1000000;
void timer_monotonic_get(struct mono_time *mt)
{
uint64_t current_tick;
uint64_t usecs_elapsed;
if (!mono_counter.initialized) {
init_timer();
mono_counter.last_value = mct_raw_value();
mono_counter.initialized = 1;
}
current_tick = mct_raw_value();
usecs_elapsed = (current_tick - mono_counter.last_value) /
clocks_per_usec;
/* 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;
}