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Diffstat (limited to 'arch/arm/cpu/armv7/s5p-common/timer.c')
-rw-r--r--arch/arm/cpu/armv7/s5p-common/timer.c192
1 files changed, 192 insertions, 0 deletions
diff --git a/arch/arm/cpu/armv7/s5p-common/timer.c b/arch/arm/cpu/armv7/s5p-common/timer.c
new file mode 100644
index 0000000000..04906503e6
--- /dev/null
+++ b/arch/arm/cpu/armv7/s5p-common/timer.c
@@ -0,0 +1,192 @@
+/*
+ * Copyright (C) 2009 Samsung Electronics
+ * Heungjun Kim <riverful.kim@samsung.com>
+ * Inki Dae <inki.dae@samsung.com>
+ * Minkyu Kang <mk7.kang@samsung.com>
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * 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., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <asm/arch/pwm.h>
+#include <asm/arch/clk.h>
+
+#define PRESCALER_1 (16 - 1) /* prescaler of timer 2, 3, 4 */
+#define MUX_DIV_2 1 /* 1/2 period */
+#define MUX_DIV_4 2 /* 1/4 period */
+#define MUX_DIV_8 3 /* 1/8 period */
+#define MUX_DIV_16 4 /* 1/16 period */
+#define MUX4_DIV_SHIFT 16
+
+#define TCON_TIMER4_SHIFT 20
+
+static unsigned long count_value;
+
+/* Internal tick units */
+static unsigned long long timestamp; /* Monotonic incrementing timer */
+static unsigned long lastdec; /* Last decremneter snapshot */
+
+/* macro to read the 16 bit timer */
+static inline struct s5p_timer *s5p_get_base_timer(void)
+{
+ return (struct s5p_timer *)samsung_get_base_timer();
+}
+
+int timer_init(void)
+{
+ struct s5p_timer *const timer = s5p_get_base_timer();
+ u32 val;
+
+ /*
+ * @ PWM Timer 4
+ * Timer Freq(HZ) =
+ * PWM_CLK / { (prescaler_value + 1) * (divider_value) }
+ */
+
+ /* set prescaler : 16 */
+ /* set divider : 2 */
+ writel((PRESCALER_1 & 0xff) << 8, &timer->tcfg0);
+ writel((MUX_DIV_2 & 0xf) << MUX4_DIV_SHIFT, &timer->tcfg1);
+
+ if (count_value == 0) {
+ /* reset initial value */
+ /* count_value = 2085937.5(HZ) (per 1 sec)*/
+ count_value = get_pwm_clk() / ((PRESCALER_1 + 1) *
+ (MUX_DIV_2 + 1));
+
+ /* count_value / 100 = 20859.375(HZ) (per 10 msec) */
+ count_value = count_value / 100;
+ }
+
+ /* set count value */
+ writel(count_value, &timer->tcntb4);
+ lastdec = count_value;
+
+ val = (readl(&timer->tcon) & ~(0x07 << TCON_TIMER4_SHIFT)) |
+ TCON4_AUTO_RELOAD;
+
+ /* auto reload & manual update */
+ writel(val | TCON4_UPDATE, &timer->tcon);
+
+ /* start PWM timer 4 */
+ writel(val | TCON4_START, &timer->tcon);
+
+ timestamp = 0;
+
+ return 0;
+}
+
+/*
+ * timer without interrupts
+ */
+void reset_timer(void)
+{
+ reset_timer_masked();
+}
+
+unsigned long get_timer(unsigned long base)
+{
+ return get_timer_masked() - base;
+}
+
+void set_timer(unsigned long t)
+{
+ timestamp = t;
+}
+
+/* delay x useconds */
+void __udelay(unsigned long usec)
+{
+ unsigned long tmo, tmp;
+
+ if (usec >= 1000) {
+ /*
+ * if "big" number, spread normalization
+ * to seconds
+ * 1. start to normalize for usec to ticks per sec
+ * 2. find number of "ticks" to wait to achieve target
+ * 3. finish normalize.
+ */
+ tmo = usec / 1000;
+ tmo *= (CONFIG_SYS_HZ * count_value / 10);
+ tmo /= 1000;
+ } else {
+ /* else small number, don't kill it prior to HZ multiply */
+ tmo = usec * CONFIG_SYS_HZ * count_value / 10;
+ tmo /= (1000 * 1000);
+ }
+
+ /* get current timestamp */
+ tmp = get_timer(0);
+
+ /* if setting this fordward will roll time stamp */
+ /* reset "advancing" timestamp to 0, set lastdec value */
+ /* else, set advancing stamp wake up time */
+ if ((tmo + tmp + 1) < tmp)
+ reset_timer_masked();
+ else
+ tmo += tmp;
+
+ /* loop till event */
+ while (get_timer_masked() < tmo)
+ ; /* nop */
+}
+
+void reset_timer_masked(void)
+{
+ struct s5p_timer *const timer = s5p_get_base_timer();
+
+ /* reset time */
+ lastdec = readl(&timer->tcnto4);
+ timestamp = 0;
+}
+
+unsigned long get_timer_masked(void)
+{
+ struct s5p_timer *const timer = s5p_get_base_timer();
+ unsigned long now = readl(&timer->tcnto4);
+
+ if (lastdec >= now)
+ timestamp += lastdec - now;
+ else
+ timestamp += lastdec + count_value - now;
+
+ lastdec = now;
+
+ return timestamp;
+}
+
+/*
+ * This function is derived from PowerPC code (read timebase as long long).
+ * On ARM it just returns the timer value.
+ */
+unsigned long long get_ticks(void)
+{
+ return get_timer(0);
+}
+
+/*
+ * This function is derived from PowerPC code (timebase clock frequency).
+ * On ARM it returns the number of timer ticks per second.
+ */
+unsigned long get_tbclk(void)
+{
+ return CONFIG_SYS_HZ;
+}