ARM: 5674/1: Add clocksource/clockevent support for w90p910 platform

Add clocksource/clockevent support for w90p910 platform.

Signed-off-by: Wan ZongShun <mcuos.com@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 127 insertions, 24 deletions

diff --git a/arch/arm/mach-w90x900/time.c b/arch/arm/mach-w90x900/time.c
index bcc838f6b393..5e06770e6014 100644
--- a/arch/arm/mach-w90x900/time.c
+++ b/arch/arm/mach-w90x900/time.c
@@ -3,7 +3,7 @@
  *
  * Based on linux/arch/arm/plat-s3c24xx/time.c by Ben Dooks
  *
- * Copyright (c) 2008 Nuvoton technology corporation
+ * Copyright (c) 2009 Nuvoton technology corporation
  * All rights reserved.
  *
  * Wan ZongShun <mcuos.com@gmail.com>
@@ -23,6 +23,8 @@
 #include <linux/clk.h>
 #include <linux/io.h>
 #include <linux/leds.h>
+#include <linux/clocksource.h>
+#include <linux/clockchips.h>
 
 #include <asm/mach-types.h>
 #include <asm/mach/irq.h>
@@ -31,49 +33,150 @@
 #include <mach/map.h>
 #include <mach/regs-timer.h>
 
-static unsigned long w90x900_gettimeoffset(void)
+#define RESETINT        0x1f
+#define PERIOD          (0x01 << 27)
+#define ONESHOT         (0x00 << 27)
+#define COUNTEN         (0x01 << 30)
+#define INTEN           (0x01 << 29)
+
+#define TICKS_PER_SEC   100
+#define PRESCALE        0x63 /* Divider = prescale + 1 */
+
+unsigned int timer0_load;
+
+static void w90p910_clockevent_setmode(enum clock_event_mode mode,
+                struct clock_event_device *clk)
 {
+        unsigned int val;
+
+        val = __raw_readl(REG_TCSR0);
+        val &= ~(0x03 << 27);
+
+        switch (mode) {
+        case CLOCK_EVT_MODE_PERIODIC:
+                __raw_writel(timer0_load, REG_TICR0);
+                val |= (PERIOD | COUNTEN | INTEN | PRESCALE);
+                break;
+
+        case CLOCK_EVT_MODE_ONESHOT:
+                val |= (ONESHOT | COUNTEN | INTEN | PRESCALE);
+                break;
+
+        case CLOCK_EVT_MODE_UNUSED:
+        case CLOCK_EVT_MODE_SHUTDOWN:
+        case CLOCK_EVT_MODE_RESUME:
+                break;
+        }
+
+        __raw_writel(val, REG_TCSR0);
+}
+
+static int w90p910_clockevent_setnextevent(unsigned long evt,
+                struct clock_event_device *clk)
+{
+        unsigned int val;
+
+        __raw_writel(evt, REG_TICR0);
+
+        val = __raw_readl(REG_TCSR0);
+        val |= (COUNTEN | INTEN | PRESCALE);
+        __raw_writel(val, REG_TCSR0);
+
         return 0;
 }
 
+static struct clock_event_device w90p910_clockevent_device = {
+        .name           = "w90p910-timer0",
+        .shift          = 32,
+        .features       = CLOCK_EVT_MODE_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
+        .set_mode       = w90p910_clockevent_setmode,
+        .set_next_event = w90p910_clockevent_setnextevent,
+        .rating         = 300,
+};
+
 /*IRQ handler for the timer*/
 
-static irqreturn_t
-w90x900_timer_interrupt(int irq, void *dev_id)
+static irqreturn_t w90p910_timer0_interrupt(int irq, void *dev_id)
 {
-        timer_tick();
+        struct clock_event_device *evt = &w90p910_clockevent_device;
+
         __raw_writel(0x01, REG_TISR); /* clear TIF0 */
+
+        evt->event_handler(evt);
         return IRQ_HANDLED;
 }
 
-static struct irqaction w90x900_timer_irq = {
-        .name           = "w90x900 Timer Tick",
+static struct irqaction w90p910_timer0_irq = {
+        .name           = "w90p910-timer0",
         .flags          = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
-        .handler        = w90x900_timer_interrupt,
+        .handler        = w90p910_timer0_interrupt,
 };
 
-/*Set up timer reg.*/
+static void __init w90p910_clockevents_init(unsigned int rate)
+{
+        w90p910_clockevent_device.mult = div_sc(rate, NSEC_PER_SEC,
+                                        w90p910_clockevent_device.shift);
+        w90p910_clockevent_device.max_delta_ns = clockevent_delta2ns(0xffffffff,
+                                        &w90p910_clockevent_device);
+        w90p910_clockevent_device.min_delta_ns = clockevent_delta2ns(0xf,
+                                        &w90p910_clockevent_device);
+        w90p910_clockevent_device.cpumask = cpumask_of(0);
 
-static void w90x900_timer_setup(void)
+        clockevents_register_device(&w90p910_clockevent_device);
+}
+
+static cycle_t w90p910_get_cycles(struct clocksource *cs)
 {
-        __raw_writel(0, REG_TCSR0);
-        __raw_writel(0, REG_TCSR1);
-        __raw_writel(0, REG_TCSR2);
-        __raw_writel(0, REG_TCSR3);
-        __raw_writel(0, REG_TCSR4);
-        __raw_writel(0x1F, REG_TISR);
-        __raw_writel(15000000/(100 * 100), REG_TICR0);
-        __raw_writel(0x68000063, REG_TCSR0);
+        return ~__raw_readl(REG_TDR1);
 }
 
-static void __init w90x900_timer_init(void)
+static struct clocksource clocksource_w90p910 = {
+        .name   = "w90p910-timer1",
+        .rating = 200,
+        .read   = w90p910_get_cycles,
+        .mask   = CLOCKSOURCE_MASK(32),
+        .shift  = 20,
+        .flags  = CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+static void __init w90p910_clocksource_init(unsigned int rate)
 {
-        w90x900_timer_setup();
-        setup_irq(IRQ_TIMER0, &w90x900_timer_irq);
+        unsigned int val;
+
+        __raw_writel(0xffffffff, REG_TICR1);
+
+        val = __raw_readl(REG_TCSR1);
+        val |= (COUNTEN | PERIOD);
+        __raw_writel(val, REG_TCSR1);
+
+        clocksource_w90p910.mult =
+                clocksource_khz2mult((rate / 1000), clocksource_w90p910.shift);
+        clocksource_register(&clocksource_w90p910);
+}
+
+static void __init w90p910_timer_init(void)
+{
+        struct clk *ck_ext = clk_get(NULL, "ext");
+        unsigned int    rate;
+
+        BUG_ON(IS_ERR(ck_ext));
+
+        rate = clk_get_rate(ck_ext);
+        clk_put(ck_ext);
+        rate = rate / (PRESCALE + 0x01);
+
+         /* set a known state */
+        __raw_writel(0x00, REG_TCSR0);
+        __raw_writel(0x00, REG_TCSR1);
+        __raw_writel(RESETINT, REG_TISR);
+        timer0_load = (rate / TICKS_PER_SEC);
+
+        setup_irq(IRQ_TIMER0, &w90p910_timer0_irq);
+
+        w90p910_clocksource_init(rate);
+        w90p910_clockevents_init(rate);
 }
 
 struct sys_timer w90x900_timer = {
-        .init           = w90x900_timer_init,
-        .offset         = w90x900_gettimeoffset,
-        .resume         = w90x900_timer_setup
+        .init           = w90p910_timer_init,
 };