netx: add support for clockevents

This is based on a patch by Luotao Fu <lfu@pengutronix.de>

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Luotao Fu <lfu@pengutronix.de>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>

arch/arm/Kconfig

@@ -287,6 +287,7 @@ config ARCH_FOOTBRIDGE
 config ARCH_NETX
 	bool "Hilscher NetX based"
 	select ARM_VIC
+	select GENERIC_CLOCKEVENTS
 	select GENERIC_TIME
 	help
 	  This enables support for systems based on the Hilscher NetX Soc

arch/arm/mach-netx/time.c

@@ -21,25 +21,80 @@
 #include <linux/interrupt.h>
 #include <linux/irq.h>
 #include <linux/clocksource.h>
+#include <linux/clockchips.h>
 #include <linux/io.h>
 
 #include <mach/hardware.h>
 #include <asm/mach/time.h>
 #include <mach/netx-regs.h>
 
+#define TIMER_CLOCKEVENT 0
 #define TIMER_CLOCKSOURCE 1
 
+static void netx_set_mode(enum clock_event_mode mode,
+		struct clock_event_device *clk)
+{
+	u32 tmode;
+
+	/* disable timer */
+	writel(0, NETX_GPIO_COUNTER_CTRL(TIMER_CLOCKEVENT));
+
+	switch (mode) {
+	case CLOCK_EVT_MODE_PERIODIC:
+		writel(LATCH, NETX_GPIO_COUNTER_MAX(TIMER_CLOCKEVENT));
+		tmode = NETX_GPIO_COUNTER_CTRL_RST_EN |
+			NETX_GPIO_COUNTER_CTRL_IRQ_EN |
+			NETX_GPIO_COUNTER_CTRL_RUN;
+		break;
+
+	case CLOCK_EVT_MODE_ONESHOT:
+		writel(0, NETX_GPIO_COUNTER_MAX(TIMER_CLOCKEVENT));
+		tmode = NETX_GPIO_COUNTER_CTRL_IRQ_EN |
+			NETX_GPIO_COUNTER_CTRL_RUN;
+		break;
+
+	default:
+		WARN(1, "%s: unhandled mode %d\n", __func__, mode);
+		/* fall through */
+
+	case CLOCK_EVT_MODE_SHUTDOWN:
+	case CLOCK_EVT_MODE_UNUSED:
+	case CLOCK_EVT_MODE_RESUME:
+		tmode = 0;
+		break;
+	}
+
+	writel(tmode, NETX_GPIO_COUNTER_CTRL(TIMER_CLOCKEVENT));
+}
+
+static int netx_set_next_event(unsigned long evt,
+		struct clock_event_device *clk)
+{
+	writel(0 - evt, NETX_GPIO_COUNTER_CURRENT(TIMER_CLOCKEVENT));
+	return 0;
+}
+
+static struct clock_event_device netx_clockevent = {
+	.name = "netx-timer" __stringify(TIMER_CLOCKEVENT),
+	.shift = 32,
+	.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
+	.set_next_event = netx_set_next_event,
+	.set_mode = netx_set_mode,
+};
+
 /*
  * IRQ handler for the timer
  */
 static irqreturn_t
 netx_timer_interrupt(int irq, void *dev_id)
 {
-	timer_tick();
+	struct clock_event_device *evt = &netx_clockevent;
 
 	/* acknowledge interrupt */
 	writel(COUNTER_BIT(0), NETX_GPIO_IRQ);
 
+	evt->event_handler(evt);
+
 	return IRQ_HANDLED;
 }
 
@@ -99,6 +154,17 @@ static void __init netx_timer_init(void)
 	clocksource_netx.mult =
 		clocksource_hz2mult(CLOCK_TICK_RATE, clocksource_netx.shift);
 	clocksource_register(&clocksource_netx);
+
+	netx_clockevent.mult = div_sc(CLOCK_TICK_RATE, NSEC_PER_SEC,
+			netx_clockevent.shift);
+	netx_clockevent.max_delta_ns =
+		clockevent_delta2ns(0xfffffffe, &netx_clockevent);
+	/* with max_delta_ns >= delta2ns(0x800) the system currently runs fine.
+	 * Adding some safety ... */
+	netx_clockevent.min_delta_ns =
+		clockevent_delta2ns(0xa00, &netx_clockevent);
+	netx_clockevent.cpumask = cpumask_of_cpu(0);
+	clockevents_register_device(&netx_clockevent);
 }
 
 struct sys_timer netx_timer = {