[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 a43a814bc7cf..4b984b120999 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 d29345501762..6f295158b168 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 = {