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linux/arch/arm/mach-davinci/time.c

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/*
* DaVinci timer subsystem
*
* Author: Kevin Hilman, MontaVista Software, Inc. <source@mvista.com>
*
* 2007 (c) MontaVista Software, Inc. This file is licensed under
* the terms of the GNU General Public License version 2. This program
* is licensed "as is" without any warranty of any kind, whether express
* or implied.
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/interrupt.h>
#include <linux/clocksource.h>
#include <linux/clockchips.h>
#include <linux/spinlock.h>
#include <linux/io.h>
#include <mach/hardware.h>
#include <asm/system.h>
#include <asm/irq.h>
#include <asm/mach/irq.h>
#include <asm/mach/time.h>
#include <asm/errno.h>
#include <mach/io.h>
static struct clock_event_device clockevent_davinci;
#define DAVINCI_TIMER0_BASE (IO_PHYS + 0x21400)
#define DAVINCI_TIMER1_BASE (IO_PHYS + 0x21800)
#define DAVINCI_WDOG_BASE (IO_PHYS + 0x21C00)
enum {
T0_BOT = 0, T0_TOP, T1_BOT, T1_TOP, NUM_TIMERS,
};
#define IS_TIMER1(id) (id & 0x2)
#define IS_TIMER0(id) (!IS_TIMER1(id))
#define IS_TIMER_TOP(id) ((id & 0x1))
#define IS_TIMER_BOT(id) (!IS_TIMER_TOP(id))
static int timer_irqs[NUM_TIMERS] = {
IRQ_TINT0_TINT12,
IRQ_TINT0_TINT34,
IRQ_TINT1_TINT12,
IRQ_TINT1_TINT34,
};
/*
* This driver configures the 2 64-bit count-up timers as 4 independent
* 32-bit count-up timers used as follows:
*
* T0_BOT: Timer 0, bottom: clockevent source for hrtimers
* T0_TOP: Timer 0, top : clocksource for generic timekeeping
* T1_BOT: Timer 1, bottom: (used by DSP in TI DSPLink code)
* T1_TOP: Timer 1, top : <unused>
*/
#define TID_CLOCKEVENT T0_BOT
#define TID_CLOCKSOURCE T0_TOP
/* Timer register offsets */
#define PID12 0x0
#define TIM12 0x10
#define TIM34 0x14
#define PRD12 0x18
#define PRD34 0x1c
#define TCR 0x20
#define TGCR 0x24
#define WDTCR 0x28
/* Timer register bitfields */
#define TCR_ENAMODE_DISABLE 0x0
#define TCR_ENAMODE_ONESHOT 0x1
#define TCR_ENAMODE_PERIODIC 0x2
#define TCR_ENAMODE_MASK 0x3
#define TGCR_TIMMODE_SHIFT 2
#define TGCR_TIMMODE_64BIT_GP 0x0
#define TGCR_TIMMODE_32BIT_UNCHAINED 0x1
#define TGCR_TIMMODE_64BIT_WDOG 0x2
#define TGCR_TIMMODE_32BIT_CHAINED 0x3
#define TGCR_TIM12RS_SHIFT 0
#define TGCR_TIM34RS_SHIFT 1
#define TGCR_RESET 0x0
#define TGCR_UNRESET 0x1
#define TGCR_RESET_MASK 0x3
#define WDTCR_WDEN_SHIFT 14
#define WDTCR_WDEN_DISABLE 0x0
#define WDTCR_WDEN_ENABLE 0x1
#define WDTCR_WDKEY_SHIFT 16
#define WDTCR_WDKEY_SEQ0 0xa5c6
#define WDTCR_WDKEY_SEQ1 0xda7e
struct timer_s {
char *name;
unsigned int id;
unsigned long period;
unsigned long opts;
unsigned long reg_base;
unsigned long tim_reg;
unsigned long prd_reg;
unsigned long enamode_shift;
struct irqaction irqaction;
};
static struct timer_s timers[];
/* values for 'opts' field of struct timer_s */
#define TIMER_OPTS_DISABLED 0x00
#define TIMER_OPTS_ONESHOT 0x01
#define TIMER_OPTS_PERIODIC 0x02
static int timer32_config(struct timer_s *t)
{
u32 tcr = davinci_readl(t->reg_base + TCR);
/* disable timer */
tcr &= ~(TCR_ENAMODE_MASK << t->enamode_shift);
davinci_writel(tcr, t->reg_base + TCR);
/* reset counter to zero, set new period */
davinci_writel(0, t->tim_reg);
davinci_writel(t->period, t->prd_reg);
/* Set enable mode */
if (t->opts & TIMER_OPTS_ONESHOT) {
tcr |= TCR_ENAMODE_ONESHOT << t->enamode_shift;
} else if (t->opts & TIMER_OPTS_PERIODIC) {
tcr |= TCR_ENAMODE_PERIODIC << t->enamode_shift;
}
davinci_writel(tcr, t->reg_base + TCR);
return 0;
}
static inline u32 timer32_read(struct timer_s *t)
{
return davinci_readl(t->tim_reg);
}
static irqreturn_t timer_interrupt(int irq, void *dev_id)
{
struct clock_event_device *evt = &clockevent_davinci;
evt->event_handler(evt);
return IRQ_HANDLED;
}
/* called when 32-bit counter wraps */
static irqreturn_t freerun_interrupt(int irq, void *dev_id)
{
return IRQ_HANDLED;
}
static struct timer_s timers[] = {
[TID_CLOCKEVENT] = {
.name = "clockevent",
.opts = TIMER_OPTS_DISABLED,
.irqaction = {
.flags = IRQF_DISABLED | IRQF_TIMER,
.handler = timer_interrupt,
}
},
[TID_CLOCKSOURCE] = {
.name = "free-run counter",
.period = ~0,
.opts = TIMER_OPTS_PERIODIC,
.irqaction = {
.flags = IRQF_DISABLED | IRQF_TIMER,
.handler = freerun_interrupt,
}
},
};
static void __init timer_init(void)
{
u32 bases[] = {DAVINCI_TIMER0_BASE, DAVINCI_TIMER1_BASE};
int i;
/* Global init of each 64-bit timer as a whole */
for(i=0; i<2; i++) {
u32 tgcr, base = bases[i];
/* Disabled, Internal clock source */
davinci_writel(0, base + TCR);
/* reset both timers, no pre-scaler for timer34 */
tgcr = 0;
davinci_writel(tgcr, base + TGCR);
/* Set both timers to unchained 32-bit */
tgcr = TGCR_TIMMODE_32BIT_UNCHAINED << TGCR_TIMMODE_SHIFT;
davinci_writel(tgcr, base + TGCR);
/* Unreset timers */
tgcr |= (TGCR_UNRESET << TGCR_TIM12RS_SHIFT) |
(TGCR_UNRESET << TGCR_TIM34RS_SHIFT);
davinci_writel(tgcr, base + TGCR);
/* Init both counters to zero */
davinci_writel(0, base + TIM12);
davinci_writel(0, base + TIM34);
}
/* Init of each timer as a 32-bit timer */
for (i=0; i< ARRAY_SIZE(timers); i++) {
struct timer_s *t = &timers[i];
if (t->name) {
t->id = i;
t->reg_base = (IS_TIMER1(t->id) ?
DAVINCI_TIMER1_BASE : DAVINCI_TIMER0_BASE);
if (IS_TIMER_BOT(t->id)) {
t->enamode_shift = 6;
t->tim_reg = t->reg_base + TIM12;
t->prd_reg = t->reg_base + PRD12;
} else {
t->enamode_shift = 22;
t->tim_reg = t->reg_base + TIM34;
t->prd_reg = t->reg_base + PRD34;
}
/* Register interrupt */
t->irqaction.name = t->name;
t->irqaction.dev_id = (void *)t;
if (t->irqaction.handler != NULL) {
setup_irq(timer_irqs[t->id], &t->irqaction);
}
timer32_config(&timers[i]);
}
}
}
/*
* clocksource
*/
static cycle_t read_cycles(struct clocksource *cs)
{
struct timer_s *t = &timers[TID_CLOCKSOURCE];
return (cycles_t)timer32_read(t);
}
static struct clocksource clocksource_davinci = {
.name = "timer0_1",
.rating = 300,
.read = read_cycles,
.mask = CLOCKSOURCE_MASK(32),
.shift = 24,
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
/*
* clockevent
*/
static int davinci_set_next_event(unsigned long cycles,
struct clock_event_device *evt)
{
struct timer_s *t = &timers[TID_CLOCKEVENT];
t->period = cycles;
timer32_config(t);
return 0;
}
static void davinci_set_mode(enum clock_event_mode mode,
struct clock_event_device *evt)
{
struct timer_s *t = &timers[TID_CLOCKEVENT];
switch (mode) {
case CLOCK_EVT_MODE_PERIODIC:
t->period = CLOCK_TICK_RATE / (HZ);
t->opts = TIMER_OPTS_PERIODIC;
timer32_config(t);
break;
case CLOCK_EVT_MODE_ONESHOT:
t->opts = TIMER_OPTS_ONESHOT;
break;
case CLOCK_EVT_MODE_UNUSED:
case CLOCK_EVT_MODE_SHUTDOWN:
t->opts = TIMER_OPTS_DISABLED;
break;
case CLOCK_EVT_MODE_RESUME:
break;
}
}
static struct clock_event_device clockevent_davinci = {
.name = "timer0_0",
.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
.shift = 32,
.set_next_event = davinci_set_next_event,
.set_mode = davinci_set_mode,
};
static void __init davinci_timer_init(void)
{
static char err[] __initdata = KERN_ERR
"%s: can't register clocksource!\n";
/* init timer hw */
timer_init();
/* setup clocksource */
clocksource_davinci.mult =
clocksource_khz2mult(CLOCK_TICK_RATE/1000,
clocksource_davinci.shift);
if (clocksource_register(&clocksource_davinci))
printk(err, clocksource_davinci.name);
/* setup clockevent */
clockevent_davinci.mult = div_sc(CLOCK_TICK_RATE, NSEC_PER_SEC,
clockevent_davinci.shift);
clockevent_davinci.max_delta_ns =
clockevent_delta2ns(0xfffffffe, &clockevent_davinci);
clockevent_davinci.min_delta_ns =
clockevent_delta2ns(1, &clockevent_davinci);
clockevent_davinci.cpumask = cpumask_of(0);
clockevents_register_device(&clockevent_davinci);
}
struct sys_timer davinci_timer = {
.init = davinci_timer_init,
};
/* reset board using watchdog timer */
void davinci_watchdog_reset(void) {
u32 tgcr, wdtcr, base = DAVINCI_WDOG_BASE;
/* disable, internal clock source */
davinci_writel(0, base + TCR);
/* reset timer, set mode to 64-bit watchdog, and unreset */
tgcr = 0;
davinci_writel(tgcr, base + TCR);
tgcr = TGCR_TIMMODE_64BIT_WDOG << TGCR_TIMMODE_SHIFT;
tgcr |= (TGCR_UNRESET << TGCR_TIM12RS_SHIFT) |
(TGCR_UNRESET << TGCR_TIM34RS_SHIFT);
davinci_writel(tgcr, base + TCR);
/* clear counter and period regs */
davinci_writel(0, base + TIM12);
davinci_writel(0, base + TIM34);
davinci_writel(0, base + PRD12);
davinci_writel(0, base + PRD34);
/* enable */
wdtcr = davinci_readl(base + WDTCR);
wdtcr |= WDTCR_WDEN_ENABLE << WDTCR_WDEN_SHIFT;
davinci_writel(wdtcr, base + WDTCR);
/* put watchdog in pre-active state */
wdtcr = (WDTCR_WDKEY_SEQ0 << WDTCR_WDKEY_SHIFT) |
(WDTCR_WDEN_ENABLE << WDTCR_WDEN_SHIFT);
davinci_writel(wdtcr, base + WDTCR);
/* put watchdog in active state */
wdtcr = (WDTCR_WDKEY_SEQ1 << WDTCR_WDKEY_SHIFT) |
(WDTCR_WDEN_ENABLE << WDTCR_WDEN_SHIFT);
davinci_writel(wdtcr, base + WDTCR);
/* write an invalid value to the WDKEY field to trigger
* a watchdog reset */
wdtcr = 0x00004000;
davinci_writel(wdtcr, base + WDTCR);
}
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