- 根目录:
- arch
- arm
- mach-davinci
- time.c
/*
* 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/io.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/sched_clock.h>
#include <asm/mach/irq.h>
#include <asm/mach/time.h>
#include <mach/cputype.h>
#include <mach/hardware.h>
#include <mach/time.h>
#include "clock.h"
static struct clock_event_device clockevent_davinci;
static unsigned int davinci_clock_tick_rate;
/*
* This driver configures the 2 64-bit count-up timers as 4 independent
* 32-bit count-up timers used as follows:
*/
enum {
TID_CLOCKEVENT,
TID_CLOCKSOURCE,
};
/* 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
/* Offsets of the 8 compare registers */
#define CMP12_0 0x60
#define CMP12_1 0x64
#define CMP12_2 0x68
#define CMP12_3 0x6c
#define CMP12_4 0x70
#define CMP12_5 0x74
#define CMP12_6 0x78
#define CMP12_7 0x7c
/* 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 flags;
void __iomem *base;
unsigned long tim_off;
unsigned long prd_off;
unsigned long enamode_shift;
struct irqaction irqaction;
};
static struct timer_s timers[];
/* values for 'opts' field of struct timer_s */
#define TIMER_OPTS_DISABLED 0x01
#define TIMER_OPTS_ONESHOT 0x02
#define TIMER_OPTS_PERIODIC 0x04
#define TIMER_OPTS_STATE_MASK 0x07
#define TIMER_OPTS_USE_COMPARE 0x80000000
#define USING_COMPARE(t) ((t)->opts & TIMER_OPTS_USE_COMPARE)
static char *id_to_name[] = {
[T0_BOT] = "timer0_0",
[T0_TOP] = "timer0_1",
[T1_BOT] = "timer1_0",
[T1_TOP] = "timer1_1",
};
static int timer32_config(struct timer_s *t)
{
u32 tcr;
struct davinci_soc_info *soc_info = &davinci_soc_info;
if (USING_COMPARE(t)) {
struct davinci_timer_instance *dtip =
soc_info->timer_info->timers;
int event_timer = ID_TO_TIMER(timers[TID_CLOCKEVENT].id);
/*
* Next interrupt should be the current time reg value plus
* the new period (using 32-bit unsigned addition/wrapping
* to 0 on overflow). This assumes that the clocksource
* is setup to count to 2^32-1 before wrapping around to 0.
*/
__raw_writel(__raw_readl(t->base + t->tim_off) + t->period,
t->base + dtip[event_timer].cmp_off);
} else {
tcr = __raw_readl(t->base + TCR);
/* disable timer */
tcr &= ~(TCR_ENAMODE_MASK << t->enamode_shift);
__raw_writel(tcr, t->base + TCR);
/* reset counter to zero, set new period */
__raw_writel(0, t->base + t->tim_off);
__raw_writel(t->period, t->base + t->prd_off);
/* 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;
__raw_writel(tcr, t->base + TCR);
}
return 0;
}
static inline u32 timer32_read(struct timer_s *t)
{
return __raw_readl(t->base + t->tim_off);
}
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_TIMER,
.handler = timer_interrupt,
}
},
[TID_CLOCKSOURCE] = {
.name = "free-run counter",
.period = ~0,
.opts = TIMER_OPTS_PERIODIC,
.irqaction = {
.flags = IRQF_TIMER,
.handler = freerun_interrupt,
}
},
};
static void __init timer_init(void)
{
struct davinci_soc_info *soc_info = &davinci_soc_info;
struct davinci_timer_instance *dtip = soc_info->timer_info->timers;
void __iomem *base[2];
int i;
/* Global init of each 64-bit timer as a whole */
for(i=0; i<2; i++) {
u32 tgcr;
base[i] = ioremap(dtip[i].base, SZ_4K);
if (WARN_ON(!base[i]))
continue;
/* Disabled, Internal clock source */
__raw_writel(0, base[i] + TCR);
/* reset both timers, no pre-scaler for timer34 */
tgcr = 0;
__raw_writel(tgcr, base[i] + TGCR);
/* Set both timers to unchained 32-bit */
tgcr = TGCR_TIMMODE_32BIT_UNCHAINED << TGCR_TIMMODE_SHIFT;
__raw_writel(tgcr, base[i] + TGCR);
/* Unreset timers */
tgcr |= (TGCR_UNRESET << TGCR_TIM12RS_SHIFT) |
(TGCR_UNRESET << TGCR_TIM34RS_SHIFT);
__raw_writel(tgcr, base[i] + TGCR);
/* Init both counters to zero */
__raw_writel(0, base[i] + TIM12);
__raw_writel(0, base[i] + TIM34);
}
/* Init of each timer as a 32-bit timer */
for (i=0; i< ARRAY_SIZE(timers); i++) {
struct timer_s *t = &timers[i];
int timer = ID_TO_TIMER(t->id);
u32 irq;
t->base = base[timer];
if (!t->base)
continue;
if (IS_TIMER_BOT(t->id)) {
t->enamode_shift = 6;
t->tim_off = TIM12;
t->prd_off = PRD12;
irq = dtip[timer].bottom_irq;
} else {
t->enamode_shift = 22;
t->tim_off = TIM34;
t->prd_off = PRD34;
irq = dtip[timer].top_irq;
}
/* Register interrupt */
t->irqaction.name = t->name;
t->irqaction.dev_id = (void *)t;
if (t->irqaction.handler != NULL) {
irq = USING_COMPARE(t) ? dtip[i].cmp_irq : irq;
setup_irq(irq, &t->irqaction);
}
}
}
/*
* 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 = {
.rating = 300,
.read = read_cycles,
.mask = CLOCKSOURCE_MASK(32),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
/*
* Overwrite weak default sched_clock with something more precise
*/
static u64 notrace davinci_read_sched_clock(void)
{
return timer32_read(&timers[TID_CLOCKSOURCE]);
}
/*
* 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 int davinci_shutdown(struct clock_event_device *evt)
{
struct timer_s *t = &timers[TID_CLOCKEVENT];
t->opts &= ~TIMER_OPTS_STATE_MASK;
t->opts |= TIMER_OPTS_DISABLED;
return 0;
}
static int davinci_set_oneshot(struct clock_event_device *evt)
{
struct timer_s *t = &timers[TID_CLOCKEVENT];
t->opts &= ~TIMER_OPTS_STATE_MASK;
t->opts |= TIMER_OPTS_ONESHOT;
return 0;
}
static int davinci_set_periodic(struct clock_event_device *evt)
{
struct timer_s *t = &timers[TID_CLOCKEVENT];
t->period = davinci_clock_tick_rate / (HZ);
t->opts &= ~TIMER_OPTS_STATE_MASK;
t->opts |= TIMER_OPTS_PERIODIC;
timer32_config(t);
return 0;
}
static struct clock_event_device clockevent_davinci = {
.features = CLOCK_EVT_FEAT_PERIODIC |
CLOCK_EVT_FEAT_ONESHOT,
.set_next_event = davinci_set_next_event,
.set_state_shutdown = davinci_shutdown,
.set_state_periodic = davinci_set_periodic,
.set_state_oneshot = davinci_set_oneshot,
};
void __init davinci_timer_init(void)
{
struct clk *timer_clk;
struct davinci_soc_info *soc_info = &davinci_soc_info;
unsigned int clockevent_id;
unsigned int clocksource_id;
int i;
clockevent_id = soc_info->timer_info->clockevent_id;
clocksource_id = soc_info->timer_info->clocksource_id;
timers[TID_CLOCKEVENT].id = clockevent_id;
timers[TID_CLOCKSOURCE].id = clocksource_id;
/*
* If using same timer for both clock events & clocksource,
* a compare register must be used to generate an event interrupt.
* This is equivalent to a oneshot timer only (not periodic).
*/
if (clockevent_id == clocksource_id) {
struct davinci_timer_instance *dtip =
soc_info->timer_info->timers;
int event_timer = ID_TO_TIMER(clockevent_id);
/* Only bottom timers can use compare regs */
if (IS_TIMER_TOP(clockevent_id))
pr_warn("%s: Invalid use of system timers. Results unpredictable.\n",
__func__);
else if ((dtip[event_timer].cmp_off == 0)
|| (dtip[event_timer].cmp_irq == 0))
pr_warn("%s: Invalid timer instance setup. Results unpredictable.\n",
__func__);
else {
timers[TID_CLOCKEVENT].opts |= TIMER_OPTS_USE_COMPARE;
clockevent_davinci.features = CLOCK_EVT_FEAT_ONESHOT;
}
}
timer_clk = clk_get(NULL, "timer0");
BUG_ON(IS_ERR(timer_clk));
clk_prepare_enable(timer_clk);
/* init timer hw */
timer_init();
davinci_clock_tick_rate = clk_get_rate(timer_clk);
/* setup clocksource */
clocksource_davinci.name = id_to_name[clocksource_id];
if (clocksource_register_hz(&clocksource_davinci,
davinci_clock_tick_rate))
pr_err("%s: can't register clocksource!\n",
clocksource_davinci.name);
sched_clock_register(davinci_read_sched_clock, 32,
davinci_clock_tick_rate);
/* setup clockevent */
clockevent_davinci.name = id_to_name[timers[TID_CLOCKEVENT].id];
clockevent_davinci.cpumask = cpumask_of(0);
clockevents_config_and_register(&clockevent_davinci,
davinci_clock_tick_rate, 1, 0xfffffffe);
for (i=0; i< ARRAY_SIZE(timers); i++)
timer32_config(&timers[i]);
}
/* reset board using watchdog timer */
void davinci_watchdog_reset(struct platform_device *pdev)
{
u32 tgcr, wdtcr;
void __iomem *base;
struct clk *wd_clk;
base = ioremap(pdev->resource[0].start, SZ_4K);
if (WARN_ON(!base))
return;
wd_clk = clk_get(&pdev->dev, NULL);
if (WARN_ON(IS_ERR(wd_clk)))
return;
clk_prepare_enable(wd_clk);
/* disable, internal clock source */
__raw_writel(0, base + TCR);
/* reset timer, set mode to 64-bit watchdog, and unreset */
tgcr = 0;
__raw_writel(tgcr, base + TGCR);
tgcr = TGCR_TIMMODE_64BIT_WDOG << TGCR_TIMMODE_SHIFT;
tgcr |= (TGCR_UNRESET << TGCR_TIM12RS_SHIFT) |
(TGCR_UNRESET << TGCR_TIM34RS_SHIFT);
__raw_writel(tgcr, base + TGCR);
/* clear counter and period regs */
__raw_writel(0, base + TIM12);
__raw_writel(0, base + TIM34);
__raw_writel(0, base + PRD12);
__raw_writel(0, base + PRD34);
/* put watchdog in pre-active state */
wdtcr = __raw_readl(base + WDTCR);
wdtcr = (WDTCR_WDKEY_SEQ0 << WDTCR_WDKEY_SHIFT) |
(WDTCR_WDEN_ENABLE << WDTCR_WDEN_SHIFT);
__raw_writel(wdtcr, base + WDTCR);
/* put watchdog in active state */
wdtcr = (WDTCR_WDKEY_SEQ1 << WDTCR_WDKEY_SHIFT) |
(WDTCR_WDEN_ENABLE << WDTCR_WDEN_SHIFT);
__raw_writel(wdtcr, base + WDTCR);
/* write an invalid value to the WDKEY field to trigger
* a watchdog reset */
wdtcr = 0x00004000;
__raw_writel(wdtcr, base + WDTCR);
}