[ARM] 4593/1: ns9xxx: implement generic clockevents

Signed-off-by: Uwe Kleine-König <ukleinek@informatik.uni-freiburg.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

2 files changed, 109 insertions, 42 deletions

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index a43a814bc7c..4b984b12099 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -320,6 +320,7 @@ config ARCH_NS9XXX
 	bool "NetSilicon NS9xxx"
 	select GENERIC_GPIO
 	select GENERIC_TIME
+	select GENERIC_CLOCKEVENTS
 	help
 	  Say Y here if you intend to run this kernel on a NetSilicon NS9xxx
 	  System.
diff --git a/arch/arm/mach-ns9xxx/time.c b/arch/arm/mach-ns9xxx/time.c
index d2934550176..6f295158b16 100644
--- a/arch/arm/mach-ns9xxx/time.c
+++ b/arch/arm/mach-ns9xxx/time.c
@@ -13,6 +13,7 @@
 #include <linux/irq.h>
 #include <linux/stringify.h>
 #include <linux/clocksource.h>
+#include <linux/clockchips.h>
 
 #include <asm/arch-ns9xxx/regs-sys.h>
 #include <asm/arch-ns9xxx/clock.h>
@@ -20,18 +21,87 @@
 #include <asm/arch/system.h>
 #include "generic.h"
 
-#define TIMERCLOCKSELECT 64
-#define TIMER_CLOCKSOURCE 1
+#define TIMER_CLOCKSOURCE 0
+#define TIMER_CLOCKEVENT 1
+static u32 latch;
 
-static irqreturn_t
-ns9xxx_timer_interrupt(int irq, void *dev_id)
+static cycle_t ns9xxx_clocksource_read(void)
+{
+	return SYS_TR(TIMER_CLOCKSOURCE);
+}
+
+static struct clocksource ns9xxx_clocksource = {
+	.name	= "ns9xxx-timer" __stringify(TIMER_CLOCKSOURCE),
+	.rating	= 300,
+	.read	= ns9xxx_clocksource_read,
+	.mask	= CLOCKSOURCE_MASK(32),
+	.shift	= 20,
+	.flags	= CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+static void ns9xxx_clockevent_setmode(enum clock_event_mode mode,
+		struct clock_event_device *clk)
+{
+	u32 tc = SYS_TC(TIMER_CLOCKEVENT);
+
+	switch(mode) {
+	case CLOCK_EVT_MODE_PERIODIC:
+		SYS_TRC(TIMER_CLOCKEVENT) = latch;
+		REGSET(tc, SYS_TCx, REN, EN);
+		REGSET(tc, SYS_TCx, INTS, EN);
+		REGSET(tc, SYS_TCx, TEN, EN);
+		break;
+
+	case CLOCK_EVT_MODE_ONESHOT:
+		REGSET(tc, SYS_TCx, REN, DIS);
+		REGSET(tc, SYS_TCx, INTS, EN);
+
+		/* fall through */
+
+	case CLOCK_EVT_MODE_UNUSED:
+	case CLOCK_EVT_MODE_SHUTDOWN:
+	case CLOCK_EVT_MODE_RESUME:
+	default:
+		REGSET(tc, SYS_TCx, TEN, DIS);
+		break;
+	}
+
+	SYS_TC(TIMER_CLOCKEVENT) = tc;
+}
+
+static int ns9xxx_clockevent_setnextevent(unsigned long evt,
+		struct clock_event_device *clk)
+{
+	u32 tc = SYS_TC(TIMER_CLOCKEVENT);
+
+	if (REGGET(tc, SYS_TCx, TEN)) {
+		REGSET(tc, SYS_TCx, TEN, DIS);
+		SYS_TC(TIMER_CLOCKEVENT) = tc;
+	}
+
+	REGSET(tc, SYS_TCx, TEN, EN);
+
+	SYS_TRC(TIMER_CLOCKEVENT) = evt;
+
+	SYS_TC(TIMER_CLOCKEVENT) = tc;
+
+	return 0;
+}
+
+static struct clock_event_device ns9xxx_clockevent_device = {
+	.name		= "ns9xxx-timer" __stringify(TIMER_CLOCKEVENT),
+	.shift		= 20,
+	.features	= CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
+	.set_mode	= ns9xxx_clockevent_setmode,
+	.set_next_event	= ns9xxx_clockevent_setnextevent,
+};
+
+static irqreturn_t ns9xxx_clockevent_handler(int irq, void *dev_id)
 {
 	int timerno = irq - IRQ_TIMER0;
 	u32 tc;
 
-	write_seqlock(&xtime_lock);
-	timer_tick();
-	write_sequnlock(&xtime_lock);
+	struct clock_event_device *evt = &ns9xxx_clockevent_device;
 
 	/* clear irq */
 	tc = SYS_TC(timerno);
@@ -44,50 +114,21 @@ ns9xxx_timer_interrupt(int irq, void *dev_id)
 	REGSET(tc, SYS_TCx, INTC, UNSET);
 	SYS_TC(timerno) = tc;
 
-	return IRQ_HANDLED;
-}
-
-static struct irqaction ns9xxx_timer_irq = {
-	.name = "NS9xxx Timer Tick",
-	.flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
-	.handler = ns9xxx_timer_interrupt,
-};
+	evt->event_handler(evt);
 
-static cycle_t ns9xxx_clocksource_read(void)
-{
-	return SYS_TR(TIMER_CLOCKSOURCE);
+	return IRQ_HANDLED;
 }
 
-static struct clocksource ns9xxx_clocksource = {
-	.name	= "ns9xxx-timer" __stringify(TIMER_CLOCKSOURCE),
-	.rating	= 300,
-	.read	= ns9xxx_clocksource_read,
-	.mask	= CLOCKSOURCE_MASK(32),
-	.shift	= 20,
-	.flags	= CLOCK_SOURCE_IS_CONTINUOUS,
+static struct irqaction ns9xxx_clockevent_action = {
+	.name		= "ns9xxx-timer" __stringify(TIMER_CLOCKEVENT),
+	.flags		= IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
+	.handler	= ns9xxx_clockevent_handler,
 };
 
 static void __init ns9xxx_timer_init(void)
 {
 	int tc;
 
-	/* disable timer */
-	if ((tc = SYS_TC(0)) & SYS_TCx_TEN)
-		SYS_TC(0) = tc & ~SYS_TCx_TEN;
-
-	SYS_TRC(0) = SH_DIV(ns9xxx_cpuclock(), (TIMERCLOCKSELECT * HZ), 0);
-
-	REGSET(tc, SYS_TCx, TEN, EN);
-	REGSET(tc, SYS_TCx, TLCS, DIV64); /* This must match TIMERCLOCKSELECT */
-	REGSET(tc, SYS_TCx, INTS, EN);
-	REGSET(tc, SYS_TCx, UDS, DOWN);
-	REGSET(tc, SYS_TCx, TDBG, STOP);
-	REGSET(tc, SYS_TCx, TSZ, 32);
-	REGSET(tc, SYS_TCx, REN, EN);
-	SYS_TC(0) = tc;
-
-	setup_irq(IRQ_TIMER0, &ns9xxx_timer_irq);
-
 	tc = SYS_TC(TIMER_CLOCKSOURCE);
 	if (REGGET(tc, SYS_TCx, TEN)) {
 		REGSET(tc, SYS_TCx, TEN, DIS);
@@ -111,6 +152,31 @@ static void __init ns9xxx_timer_init(void)
 			ns9xxx_clocksource.shift);
 
 	clocksource_register(&ns9xxx_clocksource);
+
+	latch = SH_DIV(ns9xxx_cpuclock(), HZ, 0);
+
+	tc = SYS_TC(TIMER_CLOCKEVENT);
+	REGSET(tc, SYS_TCx, TEN, DIS);
+	REGSET(tc, SYS_TCx, TDBG, STOP);
+	REGSET(tc, SYS_TCx, TLCS, CPU);
+	REGSET(tc, SYS_TCx, TM, IEE);
+	REGSET(tc, SYS_TCx, INTS, DIS);
+	REGSET(tc, SYS_TCx, UDS, DOWN);
+	REGSET(tc, SYS_TCx, TSZ, 32);
+	REGSET(tc, SYS_TCx, REN, EN);
+	SYS_TC(TIMER_CLOCKEVENT) = tc;
+
+	ns9xxx_clockevent_device.mult = div_sc(ns9xxx_cpuclock(),
+			NSEC_PER_SEC, ns9xxx_clockevent_device.shift);
+	ns9xxx_clockevent_device.max_delta_ns =
+		clockevent_delta2ns(-1, &ns9xxx_clockevent_device);
+	ns9xxx_clockevent_device.min_delta_ns =
+		clockevent_delta2ns(1, &ns9xxx_clockevent_device);
+
+	ns9xxx_clockevent_device.cpumask = cpumask_of_cpu(0);
+	clockevents_register_device(&ns9xxx_clockevent_device);
+
+	setup_irq(IRQ_TIMER0 + TIMER_CLOCKEVENT, &ns9xxx_clockevent_action);
 }
 
 struct sys_timer ns9xxx_timer = {