Re: [PATCH] Add generic clock events support for w90p910 timer

[Wan ZongShun <mcuos.com@gmail.com>]

Dear sirs,

I fixed this patch according to Russell's advice, and added
time1 for clocksource.

Either setting 'LOCK_EVT_MODE_PERIODIC' or setting 'CLOCK_EVT_FEAT_ONESHOT' can
run in my w90p910 evaluation board. but, if I set 'future' to following:

".features	= CLOCK_EVT_MODE_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,"

If so, the timer works on the periodic mode.


Signed-off-by: Wan ZongShun <mcuos.com@gmail.com>

---
 arch/arm/Kconfig                |    2 +
 arch/arm/mach-w90x900/clock.c   |    6 ++
 arch/arm/mach-w90x900/time.c    |  151 ++++++++++++++++++++++++++++++++------
 arch/arm/mach-w90x900/w90p910.c |    2 +
 4 files changed, 137 insertions(+), 24 deletions(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index c3fed1e..8c4f03d 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -495,6 +495,8 @@ config ARCH_W90X900
 	select GENERIC_GPIO
 	select HAVE_CLK
 	select COMMON_CLKDEV
+	select GENERIC_TIME
+	select GENERIC_CLOCKEVENTS
 	help
 		Support for Nuvoton (Winbond logic dept.) ARM9 processor,You
 		can login www.mcuos.com or www.nuvoton.com to know more.
diff --git a/arch/arm/mach-w90x900/clock.c b/arch/arm/mach-w90x900/clock.c
index 49cf1fb..70b6710 100644
--- a/arch/arm/mach-w90x900/clock.c
+++ b/arch/arm/mach-w90x900/clock.c
@@ -55,6 +55,12 @@ void clk_disable(struct clk *clk)
 }
 EXPORT_SYMBOL(clk_disable);
 
+unsigned long clk_get_rate(struct clk *clk)
+{
+	return 15000000;
+}
+EXPORT_SYMBOL(clk_get_rate);
+
 void w90x900_clk_enable(struct clk *clk, int enable)
 {
 	unsigned int clocks = clk->cken;
diff --git a/arch/arm/mach-w90x900/time.c b/arch/arm/mach-w90x900/time.c
index bcc838f..5e06770 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,
 };
diff --git a/arch/arm/mach-w90x900/w90p910.c b/arch/arm/mach-w90x900/w90p910.c
index 8444eab..d33723b 100644
--- a/arch/arm/mach-w90x900/w90p910.c
+++ b/arch/arm/mach-w90x900/w90p910.c
@@ -76,6 +76,7 @@ static DEFINE_CLK(wdt, 26);
 static DEFINE_CLK(gdma, 27);
 static DEFINE_CLK(adc, 28);
 static DEFINE_CLK(usi, 29);
+static DEFINE_CLK(ext, 0);
 
 static struct clk_lookup w90p910_clkregs[] = {
 	DEF_CLKLOOK(&clk_lcd, "w90p910-lcd", NULL),
@@ -97,6 +98,7 @@ static struct clk_lookup w90p910_clkregs[] = {
 	DEF_CLKLOOK(&clk_gdma, "w90p910-gdma", NULL),
 	DEF_CLKLOOK(&clk_adc, "w90p910-adc", NULL),
 	DEF_CLKLOOK(&clk_usi, "w90p910-spi", NULL),
+	DEF_CLKLOOK(&clk_ext, NULL, "ext"),
 };
 
 /* Initial serial platform data */
-- 
1.5.6.3