2 files changed, 75 insertions, 84 deletions

diff --git a/arch/arm/cpu/armv7/s5p-common/pwm.c b/arch/arm/cpu/armv7/s5p-common/pwm.c
index 44d7bc360e..6f401b8d9e 100644
--- a/arch/arm/cpu/armv7/s5p-common/pwm.c
+++ b/arch/arm/cpu/armv7/s5p-common/pwm.c
@@ -70,7 +70,7 @@ static unsigned long pwm_calc_tin(int pwm_id, unsigned long freq)
 	return tin_parent_rate / 16;
 }
 
-#define NS_IN_HZ (1000000000UL)
+#define NS_IN_SEC 1000000000UL
 
 int pwm_config(int pwm_id, int duty_ns, int period_ns)
 {
@@ -79,7 +79,7 @@ int pwm_config(int pwm_id, int duty_ns, int period_ns)
 	unsigned int offset;
 	unsigned long tin_rate;
 	unsigned long tin_ns;
-	unsigned long period;
+	unsigned long frequency;
 	unsigned long tcon;
 	unsigned long tcnt;
 	unsigned long tcmp;
@@ -89,34 +89,24 @@ int pwm_config(int pwm_id, int duty_ns, int period_ns)
 	 * fact that anything faster than 1GHz is easily representable
 	 * by 32bits.
 	 */
-	if (period_ns > NS_IN_HZ || duty_ns > NS_IN_HZ)
+	if (period_ns > NS_IN_SEC || duty_ns > NS_IN_SEC || period_ns == 0)
 		return -ERANGE;
 
 	if (duty_ns > period_ns)
 		return -EINVAL;
 
-	period = NS_IN_HZ / period_ns;
+	frequency = NS_IN_SEC / period_ns;
 
 	/* Check to see if we are changing the clock rate of the PWM */
-	tin_rate = pwm_calc_tin(pwm_id, period);
+	tin_rate = pwm_calc_tin(pwm_id, frequency);
 
-	tin_ns = NS_IN_HZ / tin_rate;
+	tin_ns = NS_IN_SEC / tin_rate;
 	tcnt = period_ns / tin_ns;
 
 	/* Note, counters count down */
 	tcmp = duty_ns / tin_ns;
 	tcmp = tcnt - tcmp;
 
-	/*
-	 * the pwm hw only checks the compare register after a decrement,
-	 * so the pin never toggles if tcmp = tcnt
-	 */
-	if (tcmp == tcnt)
-		tcmp--;
-
-	if (tcmp < 0)
-		tcmp = 0;
-
 	/* Update the PWM register block. */
 	offset = pwm_id * 3;
 	if (pwm_id < 4) {
@@ -143,7 +133,7 @@ int pwm_init(int pwm_id, int div, int invert)
 	u32 val;
 	const struct s5p_timer *pwm =
 			(struct s5p_timer *)samsung_get_base_timer();
-	unsigned long timer_rate_hz;
+	unsigned long ticks_per_period;
 	unsigned int offset, prescaler;
 
 	/*
@@ -167,14 +157,24 @@ int pwm_init(int pwm_id, int div, int invert)
 	val |= (div & 0xf) << MUX_DIV_SHIFT(pwm_id);
 	writel(val, &pwm->tcfg1);
 
-	timer_rate_hz = get_pwm_clk() / ((prescaler + 1) *
-			(div + 1));
+	if (pwm_id == 4) {
+		/*
+		 * TODO(sjg): Use this as a countdown timer for now. We count
+		 * down from the maximum value to 0, then reset.
+		 */
+		ticks_per_period = -1UL;
+	} else {
+		const unsigned long pwm_hz = 1000;
+		unsigned long timer_rate_hz = get_pwm_clk() /
+			((prescaler + 1) * (1 << div));
 
-	timer_rate_hz = timer_rate_hz / CONFIG_SYS_HZ;
+		ticks_per_period = timer_rate_hz / pwm_hz;
+	}
 
 	/* set count value */
 	offset = pwm_id * 3;
-	writel(timer_rate_hz, &pwm->tcntb0 + offset);
+
+	writel(ticks_per_period, &pwm->tcntb0 + offset);
 
 	val = readl(&pwm->tcon) & ~(0xf << TCON_OFFSET(pwm_id));
 	if (invert && (pwm_id < 4))
diff --git a/arch/arm/cpu/armv7/s5p-common/timer.c b/arch/arm/cpu/armv7/s5p-common/timer.c
index e78c716d3f..6a0fa5862e 100644
--- a/arch/arm/cpu/armv7/s5p-common/timer.c
+++ b/arch/arm/cpu/armv7/s5p-common/timer.c
@@ -39,13 +39,33 @@ static inline struct s5p_timer *s5p_get_base_timer(void)
 	return (struct s5p_timer *)samsung_get_base_timer();
 }
 
+/**
+ * Read the countdown timer.
+ *
+ * This operates at 1MHz and counts downwards. It will wrap about every
+ * hour (2^32 microseconds).
+ *
+ * @return current value of timer
+ */
+static unsigned long timer_get_us_down(void)
+{
+	struct s5p_timer *const timer = s5p_get_base_timer();
+
+	return readl(&timer->tcnto4);
+}
+
 int timer_init(void)
 {
 	/* PWM Timer 4 */
-	pwm_init(4, MUX_DIV_2, 0);
-	pwm_config(4, 0, 0);
+	pwm_init(4, MUX_DIV_4, 0);
+	pwm_config(4, 100000, 100000);
 	pwm_enable(4);
 
+	/* Use this as the current monotonic time in us */
+	gd->arch.timer_reset_value = 0;
+
+	/* Use this as the last timer value we saw */
+	gd->arch.lastinc = timer_get_us_down();
 	reset_timer_masked();
 
 	return 0;
@@ -56,81 +76,52 @@ int timer_init(void)
  */
 unsigned long get_timer(unsigned long base)
 {
-	return get_timer_masked() - base;
-}
+	ulong now = timer_get_us_down();
+
+	/*
+	 * Increment the time by the amount elapsed since the last read.
+	 * The timer may have wrapped around, but it makes no difference to
+	 * our arithmetic here.
+	 */
+	gd->arch.timer_reset_value += gd->arch.lastinc - now;
+	gd->arch.lastinc = now;
 
-/* delay x useconds */
-void __udelay(unsigned long usec)
-{
-	struct s5p_timer *const timer = s5p_get_base_timer();
-	unsigned long tmo, tmp, count_value;
-
-	count_value = readl(&timer->tcntb4);
-
-	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);
-		tmo /= 1000;
-	} else {
-		/* else small number, don't kill it prior to HZ multiply */
-		tmo = usec * CONFIG_SYS_HZ * count_value;
-		tmo /= (1000 * 1000);
-	}
-
-	/* get current timestamp */
-	tmp = get_current_tick();
-
-	/* if setting this fordward will roll time stamp */
-	/* reset "advancing" timestamp to 0, set lastinc value */
-	/* else, set advancing stamp wake up time */
-	if ((tmo + tmp + 1) < tmp)
-		reset_timer_masked();
-	else
-		tmo += tmp;
-
-	/* loop till event */
-	while (get_current_tick() < tmo)
-		;	/* nop */
+	/* Divide by 1000 to convert from us to ms */
+	return gd->arch.timer_reset_value / 1000 - base;
 }
 
-void reset_timer_masked(void)
+unsigned long timer_get_us(void)
 {
-	struct s5p_timer *const timer = s5p_get_base_timer();
+	static unsigned long base_time_us;
 
-	/* reset time */
-	gd->arch.lastinc = readl(&timer->tcnto4);
-	gd->arch.tbl = 0;
+	struct s5p_timer *const timer =
+		(struct s5p_timer *)samsung_get_base_timer();
+	unsigned long now_downward_us = readl(&timer->tcnto4);
+
+	if (!base_time_us)
+		base_time_us = now_downward_us;
+
+	/* Note that this timer counts downward. */
+	return base_time_us - now_downward_us;
 }
 
-unsigned long get_timer_masked(void)
+/* delay x useconds */
+void __udelay(unsigned long usec)
 {
-	struct s5p_timer *const timer = s5p_get_base_timer();
-	unsigned long count_value = readl(&timer->tcntb4);
+	unsigned long count_value;
 
-	return get_current_tick() / count_value;
+	count_value = timer_get_us_down();
+	while ((int)(count_value - timer_get_us_down()) < (int)usec)
+		;
 }
 
-unsigned long get_current_tick(void)
+void reset_timer_masked(void)
 {
 	struct s5p_timer *const timer = s5p_get_base_timer();
-	unsigned long now = readl(&timer->tcnto4);
-	unsigned long count_value = readl(&timer->tcntb4);
-
-	if (gd->arch.lastinc >= now)
-		gd->arch.tbl += gd->arch.lastinc - now;
-	else
-		gd->arch.tbl += gd->arch.lastinc + count_value - now;
-
-	gd->arch.lastinc = now;
 
-	return gd->arch.tbl;
+	/* reset time */
+	gd->arch.lastinc = readl(&timer->tcnto4);
+	gd->arch.tbl = 0;
 }
 
 /*