/* linux/arch/arm/mach-msm/timer.c
*
* Copyright (C) 2007 Google, Inc.
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
#include <linux/init.h>
#include <linux/time.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/clk.h>
#include <linux/clockchips.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <asm/mach/time.h>
#include <mach/msm_iomap.h>
#define MSM_DGT_BASE (MSM_GPT_BASE + 0x10)
#define MSM_DGT_SHIFT (5)
#define TIMER_MATCH_VAL 0x0000
#define TIMER_COUNT_VAL 0x0004
#define TIMER_ENABLE 0x0008
#define TIMER_ENABLE_CLR_ON_MATCH_EN 2
#define TIMER_ENABLE_EN 1
#define TIMER_CLEAR 0x000C
#define CSR_PROTECTION 0x0020
#define CSR_PROTECTION_EN 1
#define GPT_HZ 32768
#define DGT_HZ 19200000 /* 19.2 MHz or 600 KHz after shift */
struct msm_clock {
struct clock_event_device clockevent;
struct clocksource clocksource;
struct irqaction irq;
void __iomem *regbase;
uint32_t freq;
uint32_t shift;
};
static irqreturn_t msm_timer_interrupt(int irq, void *dev_id)
{
struct clock_event_device *evt = dev_id;
evt->event_handler(evt);
return IRQ_HANDLED;
}
static cycle_t msm_gpt_read(void)
{
return readl(MSM_GPT_BASE + TIMER_COUNT_VAL);
}
static cycle_t msm_dgt_read(void)
{
return readl(MSM_DGT_BASE + TIMER_COUNT_VAL) >> MSM_DGT_SHIFT;
}
static int msm_timer_set_next_event(unsigned long cycles,
struct clock_event_device *evt)
{
struct msm_clock *clock = container_of(evt, struct msm_clock, clockevent);
uint32_t now = readl(clock->regbase + TIMER_COUNT_VAL);
uint32_t alarm = now + (cycles << clock->shift);
int late;
writel(alarm, clock->regbase + TIMER_MATCH_VAL);
now = readl(clock->regbase + TIMER_COUNT_VAL);
late = now - alarm;
if (late >= (-2 << clock->shift) && late < DGT_HZ*5) {
printk(KERN_NOTICE "msm_timer_set_next_event(%lu) clock %s, "
"alarm already expired, now %x, alarm %x, late %d\n",
cycles, clock->clockevent.name, now, alarm, late);
return -ETIME;
}
return 0;
}
static void msm_timer_set_mode(enum clock_event_mode mode,
struct clock_event_device *evt)
{
struct msm_clock *clock = container_of(evt, struct msm_clock, clockevent);
switch (mode) {
case CLOCK_EVT_MODE_RESUME:
case CLOCK_EVT_MODE_PERIODIC:
break;
case CLOCK_EVT_MODE_ONESHOT:
writel(TIMER_ENABLE_EN, clock->regbase + TIMER_ENABLE);
break;
case CLOCK_EVT_MODE_UNUSED:
case CLOCK_EVT_MODE_SHUTDOWN:
writel(0, clock->regbase + TIMER_ENABLE);
break;
}
}
static struct msm_clock msm_clocks[] = {
{
.clockevent = {
.name = "gp_timer",
.features = CLOCK_EVT_FEAT_ONESHOT,
.shift = 32,
.rating = 200,
.set_next_event = msm_timer_set_next_event,
.set_mode = msm_timer_set_mode,
},
.clocksource = {
.name = "gp_timer",
.rating = 200,
.read = msm_gpt_read,
.mask = CLOCKSOURCE_MASK(32),
.shift = 24,
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
},
.irq = {
.name = "gp_timer",
.flags = IRQF_DISABLED | IRQF_TIMER | IRQF_TRIGGER_RISING,
.handler = msm_timer_interrupt,
.dev_id = &msm_clocks[0].clockevent,
.irq = INT_GP_TIMER_EXP
},
.regbase = MSM_GPT_BASE,
.freq = GPT_HZ
},
{
.clockevent = {
.name = "dg_timer",
.features = CLOCK_EVT_FEAT_ONESHOT,
.shift = 32 + MSM_DGT_SHIFT,
.rating = 300,
.set_next_event = msm_timer_set_next_event,
.set_mode = msm_timer_set_mode,
},
.clocksource = {
.name = "dg_timer",
.rating = 300,
.read = msm_dgt_read,
.mask = CLOCKSOURCE_MASK((32 - MSM_DGT_SHIFT)),
.shift = 24 - MSM_DGT_SHIFT,
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
},
.irq = {
.name = "dg_timer",
.flags = IRQF_DISABLED | IRQF_TIMER | IRQF_TRIGGER_RISING,
.handler = msm_timer_interrupt,
.dev_id = &msm_clocks[1].clockevent,
.irq = INT_DEBUG_TIMER_EXP
},
.regbase = MSM_DGT_BASE,
.freq = DGT_HZ >> MSM_DGT_SHIFT,
.shift = MSM_DGT_SHIFT
}
};
static void __init msm_timer_init(void)
{
int i;
int res;
for (i = 0; i < ARRAY_SIZE(msm_clocks); i++) {
struct msm_clock *clock = &msm_clocks[i];
struct clock_event_device *ce = &clock->clockevent;
struct clocksource *cs = &clock->clocksource;
writel(0, clock->regbase + TIMER_ENABLE);
writel(0, clock->regbase + TIMER_CLEAR);
writel(~0, clock->regbase + TIMER_MATCH_VAL);
ce->mult = div_sc(clock->freq, NSEC_PER_SEC, ce->shift);
/* allow at least 10 seconds to notice that the timer wrapped */
ce->max_delta_ns =
clockevent_delta2ns(0xf0000000 >> clock->shift, ce);
/* 4 gets rounded down to 3 */
ce->min_delta_ns = clockevent_delta2ns(4, ce);
ce->cpumask = cpumask_of_cpu(0);
cs->mult = clocksource_hz2mult(clock->freq, cs->shift);
res = clocksource_register(cs);
if (res)
printk(KERN_ERR "msm_timer_init: clocksource_register "
"failed for %s\n", cs->name);
res = setup_irq(clock->irq.irq, &clock->irq);
if (res)
printk(KERN_ERR "msm_timer_init: setup_irq "
"failed for %s\n", cs->name);
clockevents_register_device(ce);
}
}
struct sys_timer msm_timer = {
.init = msm_timer_init
};
