From 075192ae807579448afcc0833bd349ccce057825 Mon Sep 17 00:00:00 2001
From: Kevin Hilman <khilman@mvista.com>
Date: Thu, 8 Mar 2007 20:32:19 +0100
Subject: [ARM] 4262/1: OMAP: clocksource and clockevent support
Update OMAP1 to enable support for hrtimers and dynticks by using new clocksource and clockevent infrastructure.
Signed-off-by: Kevin Hilman <khilman@mvista.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
---
arch/arm/mach-omap1/time.c | 206 +++++++++++++++++++++++++++++----------------
1 file changed, 133 insertions(+), 73 deletions(-)
(limited to 'arch/arm/mach-omap1')
diff --git a/arch/arm/mach-omap1/time.c b/arch/arm/mach-omap1/time.c
index 1b7e4a5..85e048b 100644
--- a/arch/arm/mach-omap1/time.c
+++ b/arch/arm/mach-omap1/time.c
@@ -39,6 +39,10 @@
#include <linux/interrupt.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/clocksource.h>
+#include <linux/clockchips.h>
#include <asm/system.h>
#include <asm/hardware.h>
@@ -48,13 +52,7 @@
#include <asm/mach/irq.h>
#include <asm/mach/time.h>
-struct sys_timer omap_timer;
-/*
- * ---------------------------------------------------------------------------
- * MPU timer
- * ---------------------------------------------------------------------------
- */
#define OMAP_MPU_TIMER_BASE OMAP_MPU_TIMER1_BASE
#define OMAP_MPU_TIMER_OFFSET 0x100
@@ -88,21 +86,6 @@ static inline unsigned long long cycles_2_ns(unsigned long long cyc)
return (cyc * cyc2ns_scale) >> CYC2NS_SCALE_FACTOR;
}
-/*
- * MPU_TICKS_PER_SEC must be an even number, otherwise machinecycles_to_usecs
- * will break. On P2, the timer count rate is 6.5 MHz after programming PTV
- * with 0. This divides the 13MHz input by 2, and is undocumented.
- */
-#if defined(CONFIG_MACH_OMAP_PERSEUS2) || defined(CONFIG_MACH_OMAP_FSAMPLE)
-/* REVISIT: This ifdef construct should be replaced by a query to clock
- * framework to see if timer base frequency is 12.0, 13.0 or 19.2 MHz.
- */
-#define MPU_TICKS_PER_SEC (13000000 / 2)
-#else
-#define MPU_TICKS_PER_SEC (12000000 / 2)
-#endif
-
-#define MPU_TIMER_TICK_PERIOD ((MPU_TICKS_PER_SEC / HZ) - 1)
typedef struct {
u32 cntl; /* CNTL_TIMER, R/W */
@@ -120,98 +103,164 @@ static inline unsigned long omap_mpu_timer_read(int nr)
return timer->read_tim;
}
-static inline void omap_mpu_timer_start(int nr, unsigned long load_val)
+static inline void omap_mpu_set_autoreset(int nr)
{
volatile omap_mpu_timer_regs_t* timer = omap_mpu_timer_base(nr);
- timer->cntl = MPU_TIMER_CLOCK_ENABLE;
- udelay(1);
- timer->load_tim = load_val;
- udelay(1);
- timer->cntl = (MPU_TIMER_CLOCK_ENABLE | MPU_TIMER_AR | MPU_TIMER_ST);
+ timer->cntl = timer->cntl | MPU_TIMER_AR;
}
-unsigned long omap_mpu_timer_ticks_to_usecs(unsigned long nr_ticks)
+static inline void omap_mpu_remove_autoreset(int nr)
{
- unsigned long long nsec;
+ volatile omap_mpu_timer_regs_t* timer = omap_mpu_timer_base(nr);
- nsec = cycles_2_ns((unsigned long long)nr_ticks);
- return (unsigned long)nsec / 1000;
+ timer->cntl = timer->cntl & ~MPU_TIMER_AR;
}
-/*
- * Last processed system timer interrupt
- */
-static unsigned long omap_mpu_timer_last = 0;
+static inline void omap_mpu_timer_start(int nr, unsigned long load_val,
+ int autoreset)
+{
+ volatile omap_mpu_timer_regs_t* timer = omap_mpu_timer_base(nr);
+ unsigned int timerflags = (MPU_TIMER_CLOCK_ENABLE | MPU_TIMER_ST);
+
+ if (autoreset) timerflags |= MPU_TIMER_AR;
+
+ timer->cntl = MPU_TIMER_CLOCK_ENABLE;
+ udelay(1);
+ timer->load_tim = load_val;
+ udelay(1);
+ timer->cntl = timerflags;
+}
/*
- * Returns elapsed usecs since last system timer interrupt
+ * ---------------------------------------------------------------------------
+ * MPU timer 1 ... count down to zero, interrupt, reload
+ * ---------------------------------------------------------------------------
*/
-static unsigned long omap_mpu_timer_gettimeoffset(void)
+static int omap_mpu_set_next_event(unsigned long cycles,
+ struct clock_event_device *evt)
{
- unsigned long now = 0 - omap_mpu_timer_read(0);
- unsigned long elapsed = now - omap_mpu_timer_last;
+ omap_mpu_timer_start(0, cycles, 0);
+ return 0;
+}
- return omap_mpu_timer_ticks_to_usecs(elapsed);
+static void omap_mpu_set_mode(enum clock_event_mode mode,
+ struct clock_event_device *evt)
+{
+ switch (mode) {
+ case CLOCK_EVT_MODE_PERIODIC:
+ omap_mpu_set_autoreset(0);
+ break;
+ case CLOCK_EVT_MODE_ONESHOT:
+ omap_mpu_remove_autoreset(0);
+ break;
+ case CLOCK_EVT_MODE_UNUSED:
+ case CLOCK_EVT_MODE_SHUTDOWN:
+ break;
+ }
}
-/*
- * Elapsed time between interrupts is calculated using timer0.
- * Latency during the interrupt is calculated using timer1.
- * Both timer0 and timer1 are counting at 6MHz (P2 6.5MHz).
- */
-static irqreturn_t omap_mpu_timer_interrupt(int irq, void *dev_id)
+static struct clock_event_device clockevent_mpu_timer1 = {
+ .name = "mpu_timer1",
+ .features = CLOCK_EVT_FEAT_PERIODIC, CLOCK_EVT_FEAT_ONESHOT,
+ .shift = 32,
+ .set_next_event = omap_mpu_set_next_event,
+ .set_mode = omap_mpu_set_mode,
+};
+
+static irqreturn_t omap_mpu_timer1_interrupt(int irq, void *dev_id)
{
- unsigned long now, latency;
+ struct clock_event_device *evt = &clockevent_mpu_timer1;
- write_seqlock(&xtime_lock);
- now = 0 - omap_mpu_timer_read(0);
- latency = MPU_TICKS_PER_SEC / HZ - omap_mpu_timer_read(1);
- omap_mpu_timer_last = now - latency;
- timer_tick();
- write_sequnlock(&xtime_lock);
+ evt->event_handler(evt);
return IRQ_HANDLED;
}
-static struct irqaction omap_mpu_timer_irq = {
- .name = "mpu timer",
+static struct irqaction omap_mpu_timer1_irq = {
+ .name = "mpu_timer1",
.flags = IRQF_DISABLED | IRQF_TIMER,
- .handler = omap_mpu_timer_interrupt,
+ .handler = omap_mpu_timer1_interrupt,
};
-static unsigned long omap_mpu_timer1_overflows;
-static irqreturn_t omap_mpu_timer1_interrupt(int irq, void *dev_id)
+static __init void omap_init_mpu_timer(unsigned long rate)
+{
+ set_cyc2ns_scale(rate / 1000);
+
+ setup_irq(INT_TIMER1, &omap_mpu_timer1_irq);
+ omap_mpu_timer_start(0, (rate / HZ) - 1, 1);
+
+ clockevent_mpu_timer1.mult = div_sc(rate, NSEC_PER_SEC,
+ clockevent_mpu_timer1.shift);
+ clockevent_mpu_timer1.max_delta_ns =
+ clockevent_delta2ns(-1, &clockevent_mpu_timer1);
+ clockevent_mpu_timer1.min_delta_ns =
+ clockevent_delta2ns(1, &clockevent_mpu_timer1);
+
+ clockevent_mpu_timer1.cpumask = cpumask_of_cpu(0);
+ clockevents_register_device(&clockevent_mpu_timer1);
+}
+
+
+/*
+ * ---------------------------------------------------------------------------
+ * MPU timer 2 ... free running 32-bit clock source and scheduler clock
+ * ---------------------------------------------------------------------------
+ */
+
+static unsigned long omap_mpu_timer2_overflows;
+
+static irqreturn_t omap_mpu_timer2_interrupt(int irq, void *dev_id)
{
- omap_mpu_timer1_overflows++;
+ omap_mpu_timer2_overflows++;
return IRQ_HANDLED;
}
-static struct irqaction omap_mpu_timer1_irq = {
- .name = "mpu timer1 overflow",
+static struct irqaction omap_mpu_timer2_irq = {
+ .name = "mpu_timer2",
.flags = IRQF_DISABLED,
- .handler = omap_mpu_timer1_interrupt,
+ .handler = omap_mpu_timer2_interrupt,
};
-static __init void omap_init_mpu_timer(void)
+static cycle_t mpu_read(void)
{
- set_cyc2ns_scale(MPU_TICKS_PER_SEC / 1000);
- omap_timer.offset = omap_mpu_timer_gettimeoffset;
- setup_irq(INT_TIMER1, &omap_mpu_timer1_irq);
- setup_irq(INT_TIMER2, &omap_mpu_timer_irq);
- omap_mpu_timer_start(0, 0xffffffff);
- omap_mpu_timer_start(1, MPU_TIMER_TICK_PERIOD);
+ return ~omap_mpu_timer_read(1);
+}
+
+static struct clocksource clocksource_mpu = {
+ .name = "mpu_timer2",
+ .rating = 300,
+ .read = mpu_read,
+ .mask = CLOCKSOURCE_MASK(32),
+ .shift = 24,
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+static void __init omap_init_clocksource(unsigned long rate)
+{
+ static char err[] __initdata = KERN_ERR
+ "%s: can't register clocksource!\n";
+
+ clocksource_mpu.mult
+ = clocksource_khz2mult(rate/1000, clocksource_mpu.shift);
+
+ setup_irq(INT_TIMER2, &omap_mpu_timer2_irq);
+ omap_mpu_timer_start(1, ~0, 1);
+
+ if (clocksource_register(&clocksource_mpu))
+ printk(err, clocksource_mpu.name);
}
+
/*
* Scheduler clock - returns current time in nanosec units.
*/
unsigned long long sched_clock(void)
{
- unsigned long ticks = 0 - omap_mpu_timer_read(0);
+ unsigned long ticks = 0 - omap_mpu_timer_read(1);
unsigned long long ticks64;
- ticks64 = omap_mpu_timer1_overflows;
+ ticks64 = omap_mpu_timer2_overflows;
ticks64 <<= 32;
ticks64 |= ticks;
@@ -225,10 +274,21 @@ unsigned long long sched_clock(void)
*/
static void __init omap_timer_init(void)
{
- omap_init_mpu_timer();
+ struct clk *ck_ref = clk_get(NULL, "ck_ref");
+ unsigned long rate;
+
+ BUG_ON(IS_ERR(ck_ref));
+
+ rate = clk_get_rate(ck_ref);
+ clk_put(ck_ref);
+
+ /* PTV = 0 */
+ rate /= 2;
+
+ omap_init_mpu_timer(rate);
+ omap_init_clocksource(rate);
}
struct sys_timer omap_timer = {
.init = omap_timer_init,
- .offset = NULL, /* Initialized later */
};
--
cgit v1.1