Blackfin: add support for gptimer0 as a tick source
For systems where the core cycles are not a usable tick source (like SMP
or cycles gets updated), enable gptimer0 as an alternative.
Signed-off-by: Graf Yang <graf.yang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
diff --git a/arch/blackfin/kernel/time-ts.c b/arch/blackfin/kernel/time-ts.c
index 2764612..0791eba 100644
--- a/arch/blackfin/kernel/time-ts.c
+++ b/arch/blackfin/kernel/time-ts.c
@@ -20,8 +20,9 @@
#include <asm/blackfin.h>
#include <asm/time.h>
+#include <asm/gptimers.h>
-#ifdef CONFIG_CYCLES_CLOCKSOURCE
+#if defined(CONFIG_CYCLES_CLOCKSOURCE)
/* Accelerators for sched_clock()
* convert from cycles(64bits) => nanoseconds (64bits)
@@ -58,15 +59,15 @@
return (cyc * cyc2ns_scale) >> CYC2NS_SCALE_FACTOR;
}
-static cycle_t read_cycles(struct clocksource *cs)
+static cycle_t bfin_read_cycles(struct clocksource *cs)
{
return __bfin_cycles_off + (get_cycles() << __bfin_cycles_mod);
}
-static struct clocksource clocksource_bfin = {
- .name = "bfin_cycles",
+static struct clocksource bfin_cs_cycles = {
+ .name = "bfin_cs_cycles",
.rating = 350,
- .read = read_cycles,
+ .read = bfin_read_cycles,
.mask = CLOCKSOURCE_MASK(64),
.shift = 22,
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
@@ -74,53 +75,198 @@
unsigned long long sched_clock(void)
{
- return cycles_2_ns(read_cycles(&clocksource_bfin));
+ return cycles_2_ns(bfin_read_cycles(&bfin_cs_cycles));
}
-static int __init bfin_clocksource_init(void)
+static int __init bfin_cs_cycles_init(void)
{
set_cyc2ns_scale(get_cclk() / 1000);
- clocksource_bfin.mult = clocksource_hz2mult(get_cclk(), clocksource_bfin.shift);
+ bfin_cs_cycles.mult = \
+ clocksource_hz2mult(get_cclk(), bfin_cs_cycles.shift);
- if (clocksource_register(&clocksource_bfin))
+ if (clocksource_register(&bfin_cs_cycles))
panic("failed to register clocksource");
return 0;
}
-
#else
-# define bfin_clocksource_init()
+# define bfin_cs_cycles_init()
#endif
+#ifdef CONFIG_GPTMR0_CLOCKSOURCE
+
+void __init setup_gptimer0(void)
+{
+ disable_gptimers(TIMER0bit);
+
+ set_gptimer_config(TIMER0_id, \
+ TIMER_OUT_DIS | TIMER_PERIOD_CNT | TIMER_MODE_PWM);
+ set_gptimer_period(TIMER0_id, -1);
+ set_gptimer_pwidth(TIMER0_id, -2);
+ SSYNC();
+ enable_gptimers(TIMER0bit);
+}
+
+static cycle_t bfin_read_gptimer0(void)
+{
+ return bfin_read_TIMER0_COUNTER();
+}
+
+static struct clocksource bfin_cs_gptimer0 = {
+ .name = "bfin_cs_gptimer0",
+ .rating = 400,
+ .read = bfin_read_gptimer0,
+ .mask = CLOCKSOURCE_MASK(32),
+ .shift = 22,
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+static int __init bfin_cs_gptimer0_init(void)
+{
+ setup_gptimer0();
+
+ bfin_cs_gptimer0.mult = \
+ clocksource_hz2mult(get_sclk(), bfin_cs_gptimer0.shift);
+
+ if (clocksource_register(&bfin_cs_gptimer0))
+ panic("failed to register clocksource");
+
+ return 0;
+}
+#else
+# define bfin_cs_gptimer0_init()
+#endif
+
+#ifdef CONFIG_CORE_TIMER_IRQ_L1
+__attribute__((l1_text))
+#endif
+irqreturn_t timer_interrupt(int irq, void *dev_id);
+
+static int bfin_timer_set_next_event(unsigned long, \
+ struct clock_event_device *);
+
+static void bfin_timer_set_mode(enum clock_event_mode, \
+ struct clock_event_device *);
+
+static struct clock_event_device clockevent_bfin = {
+#if defined(CONFIG_TICKSOURCE_GPTMR0)
+ .name = "bfin_gptimer0",
+ .rating = 300,
+ .irq = IRQ_TIMER0,
+#else
+ .name = "bfin_core_timer",
+ .rating = 350,
+ .irq = IRQ_CORETMR,
+#endif
+ .shift = 32,
+ .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
+ .set_next_event = bfin_timer_set_next_event,
+ .set_mode = bfin_timer_set_mode,
+};
+
+static struct irqaction bfin_timer_irq = {
+#if defined(CONFIG_TICKSOURCE_GPTMR0)
+ .name = "Blackfin GPTimer0",
+#else
+ .name = "Blackfin CoreTimer",
+#endif
+ .flags = IRQF_DISABLED | IRQF_TIMER | \
+ IRQF_IRQPOLL | IRQF_PERCPU,
+ .handler = timer_interrupt,
+ .dev_id = &clockevent_bfin,
+};
+
+#if defined(CONFIG_TICKSOURCE_GPTMR0)
static int bfin_timer_set_next_event(unsigned long cycles,
struct clock_event_device *evt)
{
- bfin_write_TCOUNT(cycles);
- CSYNC();
+ disable_gptimers(TIMER0bit);
+
+ /* it starts counting three SCLK cycles after the TIMENx bit is set */
+ set_gptimer_pwidth(TIMER0_id, cycles - 3);
+ enable_gptimers(TIMER0bit);
return 0;
}
static void bfin_timer_set_mode(enum clock_event_mode mode,
- struct clock_event_device *evt)
+ struct clock_event_device *evt)
+{
+ switch (mode) {
+ case CLOCK_EVT_MODE_PERIODIC: {
+ set_gptimer_config(TIMER0_id, \
+ TIMER_OUT_DIS | TIMER_IRQ_ENA | \
+ TIMER_PERIOD_CNT | TIMER_MODE_PWM);
+ set_gptimer_period(TIMER0_id, get_sclk() / HZ);
+ set_gptimer_pwidth(TIMER0_id, get_sclk() / HZ - 1);
+ enable_gptimers(TIMER0bit);
+ break;
+ }
+ case CLOCK_EVT_MODE_ONESHOT:
+ disable_gptimers(TIMER0bit);
+ set_gptimer_config(TIMER0_id, \
+ TIMER_OUT_DIS | TIMER_IRQ_ENA | TIMER_MODE_PWM);
+ set_gptimer_period(TIMER0_id, 0);
+ break;
+ case CLOCK_EVT_MODE_UNUSED:
+ case CLOCK_EVT_MODE_SHUTDOWN:
+ disable_gptimers(TIMER0bit);
+ break;
+ case CLOCK_EVT_MODE_RESUME:
+ break;
+ }
+}
+
+static void bfin_timer_ack(void)
+{
+ set_gptimer_status(TIMER_GROUP1, TIMER_STATUS_TIMIL0);
+}
+
+static void __init bfin_timer_init(void)
+{
+ disable_gptimers(TIMER0bit);
+}
+
+static unsigned long __init bfin_clockevent_check(void)
+{
+ setup_irq(IRQ_TIMER0, &bfin_timer_irq);
+ return get_sclk();
+}
+
+#else /* CONFIG_TICKSOURCE_CORETMR */
+
+static int bfin_timer_set_next_event(unsigned long cycles,
+ struct clock_event_device *evt)
+{
+ bfin_write_TCNTL(TMPWR);
+ CSYNC();
+ bfin_write_TCOUNT(cycles);
+ CSYNC();
+ bfin_write_TCNTL(TMPWR | TMREN);
+ return 0;
+}
+
+static void bfin_timer_set_mode(enum clock_event_mode mode,
+ struct clock_event_device *evt)
{
switch (mode) {
case CLOCK_EVT_MODE_PERIODIC: {
unsigned long tcount = ((get_cclk() / (HZ * TIME_SCALE)) - 1);
bfin_write_TCNTL(TMPWR);
- bfin_write_TSCALE(TIME_SCALE - 1);
CSYNC();
+ bfin_write_TSCALE(TIME_SCALE - 1);
bfin_write_TPERIOD(tcount);
bfin_write_TCOUNT(tcount);
- bfin_write_TCNTL(TMPWR | TMREN | TAUTORLD);
CSYNC();
+ bfin_write_TCNTL(TMPWR | TMREN | TAUTORLD);
break;
}
case CLOCK_EVT_MODE_ONESHOT:
- bfin_write_TSCALE(TIME_SCALE - 1);
- bfin_write_TCOUNT(0);
- bfin_write_TCNTL(TMPWR | TMREN);
+ bfin_write_TCNTL(TMPWR);
CSYNC();
+ bfin_write_TSCALE(TIME_SCALE - 1);
+ bfin_write_TPERIOD(0);
+ bfin_write_TCOUNT(0);
break;
case CLOCK_EVT_MODE_UNUSED:
case CLOCK_EVT_MODE_SHUTDOWN:
@@ -132,6 +278,10 @@
}
}
+static void bfin_timer_ack(void)
+{
+}
+
static void __init bfin_timer_init(void)
{
/* power up the timer, but don't enable it just yet */
@@ -145,38 +295,32 @@
bfin_write_TPERIOD(0);
bfin_write_TCOUNT(0);
- /* now enable the timer */
CSYNC();
}
+static unsigned long __init bfin_clockevent_check(void)
+{
+ setup_irq(IRQ_CORETMR, &bfin_timer_irq);
+ return get_cclk() / TIME_SCALE;
+}
+
+void __init setup_core_timer(void)
+{
+ bfin_timer_init();
+ bfin_timer_set_mode(CLOCK_EVT_MODE_PERIODIC, NULL);
+}
+#endif /* CONFIG_TICKSOURCE_GPTMR0 */
+
/*
* timer_interrupt() needs to keep up the real-time clock,
* as well as call the "do_timer()" routine every clocktick
*/
-#ifdef CONFIG_CORE_TIMER_IRQ_L1
-__attribute__((l1_text))
-#endif
-irqreturn_t timer_interrupt(int irq, void *dev_id);
-
-static struct clock_event_device clockevent_bfin = {
- .name = "bfin_core_timer",
- .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
- .shift = 32,
- .set_next_event = bfin_timer_set_next_event,
- .set_mode = bfin_timer_set_mode,
-};
-
-static struct irqaction bfin_timer_irq = {
- .name = "Blackfin Core Timer",
- .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
- .handler = timer_interrupt,
- .dev_id = &clockevent_bfin,
-};
-
irqreturn_t timer_interrupt(int irq, void *dev_id)
{
struct clock_event_device *evt = dev_id;
+ smp_mb();
evt->event_handler(evt);
+ bfin_timer_ack();
return IRQ_HANDLED;
}
@@ -184,9 +328,8 @@
{
unsigned long timer_clk;
- timer_clk = get_cclk() / TIME_SCALE;
+ timer_clk = bfin_clockevent_check();
- setup_irq(IRQ_CORETMR, &bfin_timer_irq);
bfin_timer_init();
clockevent_bfin.mult = div_sc(timer_clk, NSEC_PER_SEC, clockevent_bfin.shift);
@@ -218,6 +361,7 @@
xtime.tv_nsec = 0;
set_normalized_timespec(&wall_to_monotonic, -xtime.tv_sec, -xtime.tv_nsec);
- bfin_clocksource_init();
+ bfin_cs_cycles_init();
+ bfin_cs_gptimer0_init();
bfin_clockevent_init();
}