From: Sangbeom Kim <sbki...@samsung.com>
Basically, PWM timer works with 33Mhz on S5P SoCs and counter
overflow every 128 secs. So it is needed 64-bit counter for
supporting proper sched_clock() by 32-bit timer. This patch
handle overflow control and can solve the problem of suspend
to resume
Signed-off-by: Sangbeom Kim <sbki...@samsung.com>
Signed-off-by: Kukjin Kim <kgene....@samsung.com>
---
arch/arm/plat-s5p/s5p-time.c | 80 +++++++++++++++++++++++++++++++++++++++--
1 files changed, 76 insertions(+), 4 deletions(-)
diff --git a/arch/arm/plat-s5p/s5p-time.c b/arch/arm/plat-s5p/s5p-time.c
index 6b26d80..ecc576f 100644
--- a/arch/arm/plat-s5p/s5p-time.c
+++ b/arch/arm/plat-s5p/s5p-time.c
@@ -36,6 +36,12 @@ static struct clk *tdiv_source;
static struct clk *timerclk;
static struct s5p_timer_source timer_source;
static unsigned long clock_count_per_tick;
+static unsigned long long s5p_sched_timer_overflows;
+static unsigned long long time_stamps;
+static unsigned long long old_overflows;
+static cycle_t last_ticks;
+static unsigned int sched_timer_running;
+static unsigned int pending_irq;
static void s5p_time_setup(enum s5p_timer_mode mode, unsigned long tcnt)
{
@@ -188,6 +194,7 @@ static void s5p_timer_resume(void)
/* source timer restart */
s5p_time_setup(timer_source.source_id, TCNT_MAX);
s5p_time_start(timer_source.source_id, PERIODIC);
+ sched_timer_running = 1;
}
static cycle_t s5p_timer_read(struct clocksource *cs)
@@ -223,6 +230,15 @@ static int s5p_set_next_event(unsigned long cycles,
return 0;
}
+static void s5p_val_init(void)
+{
+ last_ticks = 0;
+ s5p_sched_timer_overflows = 0;
+ old_overflows = 0;
+ sched_timer_running = 0;
+ pending_irq = 0;
+}
+
static void s5p_set_mode(enum clock_event_mode mode,
struct clock_event_device *evt)
{
@@ -239,6 +255,7 @@ static void s5p_set_mode(enum clock_event_mode mode,
case CLOCK_EVT_MODE_UNUSED:
case CLOCK_EVT_MODE_SHUTDOWN:
+ s5p_val_init();
break;
case CLOCK_EVT_MODE_RESUME:
@@ -322,15 +339,41 @@ static DEFINE_CLOCK_DATA(cd);
unsigned long long notrace sched_clock(void)
{
- cycle_t cyc;
+ cycle_t ticks, elapsed_ticks = 0;
+ unsigned long long increment = 0;
+ unsigned int overflow_cnt = s5p_sched_timer_overflows - old_overflows;
unsigned long irq_flags;
local_irq_save(irq_flags);
- cyc = s5p_timer_read(&time_clocksource);
-
+ ticks = s5p_timer_read(&time_clocksource);
+
+ if (likely(sched_timer_running)) {
+ if (overflow_cnt) {
+ increment = (overflow_cnt - 1)
+ *
(clocksource_cyc2ns(time_clocksource.read(&time_clocksource),
+ time_clocksource.mult, time_clocksource.shift));
+ elapsed_ticks = time_clocksource.mask - last_ticks
+ + ticks;
+ } else {
+ if (unlikely(last_ticks > ticks)) {
+ pending_irq = 1;
+ elapsed_ticks = time_clocksource.mask
+ - last_ticks + ticks;
+ s5p_sched_timer_overflows++;
+ } else {
+ elapsed_ticks = ticks - last_ticks;
+ }
+ }
+
+ time_stamps += clocksource_cyc2ns(elapsed_ticks,
+ time_clocksource.mult, time_clocksource.shift)
+ + increment;
+ old_overflows = s5p_sched_timer_overflows;
+ last_ticks = ticks;
+ }
local_irq_restore(irq_flags);
- return cyc_to_sched_clock(&cd, cyc, (u32)~0);
+ return time_stamps;
}
static void notrace s5p_update_sched_clock(void)
@@ -341,10 +384,32 @@ static void notrace s5p_update_sched_clock(void)
update_sched_clock(&cd, cyc, (u32)~0);
}
+irqreturn_t s5p_clock_source_isr(int irq, void *dev_id)
+{
+ if (unlikely(pending_irq))
+ pending_irq = 0;
+ else
+ s5p_sched_timer_overflows++;
+
+ return IRQ_HANDLED;
+}
+
+static struct irqaction s5p_clock_source_irq = {
+ .name = "s5p_source_irq",
+ .flags = IRQF_DISABLED ,
+ .handler = s5p_clock_source_isr,
+};
+
static void __init s5p_clocksource_init(void)
{
unsigned long pclk;
unsigned long clock_rate;
+ unsigned int irq_number;
+ unsigned long cstat;
+
+ /* Clear each timer interrupt pending bit */
+ cstat = __raw_readl(S3C64XX_TINT_CSTAT);
+ __raw_writel(cstat, S3C64XX_TINT_CSTAT);
pclk = clk_get_rate(timerclk);
@@ -355,11 +420,15 @@ static void __init s5p_clocksource_init(void)
s5p_time_setup(timer_source.source_id, TCNT_MAX);
s5p_time_start(timer_source.source_id, PERIODIC);
+ sched_timer_running = 1;
init_sched_clock(&cd, s5p_update_sched_clock, 32, clock_rate);
if (clocksource_register_hz(&time_clocksource, clock_rate))
panic("%s: can't register clocksource\n",
time_clocksource.name);
+
+ irq_number = timer_source.source_id + IRQ_TIMER0;
+ setup_irq(irq_number, &s5p_clock_source_irq);
}
static void __init s5p_timer_resources(void)
@@ -368,6 +437,9 @@ static void __init s5p_timer_resources(void)
unsigned long event_id = timer_source.event_id;
unsigned long source_id = timer_source.source_id;
+ s5p_val_init();
+ time_stamps = 0;
+
timerclk = clk_get(NULL, "timers");
if (IS_ERR(timerclk))
panic("failed to get timers clock for timer");
--
1.7.4.4
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