/*
* arch/arch/mach-tegra/timer.c
*
* Copyright (C) 2010 Google, Inc.
*
* Author:
* Colin Cross <ccross@google.com>
*
* 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/err.h>
#include <linux/sched.h>
#include <linux/time.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/clockchips.h>
#include <linux/clocksource.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <asm/mach/time.h>
#include <asm/localtimer.h>
#include <asm/sched_clock.h>
#include <mach/iomap.h>
#include <mach/irqs.h>
#include <mach/suspend.h>
#include "board.h"
#include "clock.h"
#define RTC_SECONDS 0x08
#define RTC_SHADOW_SECONDS 0x0c
#define RTC_MILLISECONDS 0x10
#define TIMERUS_CNTR_1US 0x10
#define TIMERUS_USEC_CFG 0x14
#define TIMERUS_CNTR_FREEZE 0x4c
#define TIMER1_BASE 0x0
#define TIMER2_BASE 0x8
#define TIMER3_BASE 0x50
#define TIMER4_BASE 0x58
#define TIMER_PTV 0x0
#define TIMER_PCR 0x4
static void __iomem *timer_reg_base = IO_ADDRESS(TEGRA_TMR1_BASE);
static void __iomem *rtc_base = IO_ADDRESS(TEGRA_RTC_BASE);
static struct timespec persistent_ts;
static u64 persistent_ms, last_persistent_ms;
#define timer_writel(value, reg) \
__raw_writel(value, timer_reg_base + (reg))
#define timer_readl(reg) \
__raw_readl(timer_reg_base + (reg))
static int tegra_timer_set_next_event(unsigned long cycles,
struct clock_event_device *evt)
{
u32 reg;
reg = 0x80000000 | ((cycles > 1) ? (cycles-1) : 0);
timer_writel(reg, TIMER3_BASE + TIMER_PTV);
return 0;
}
static void tegra_timer_set_mode(enum clock_event_mode mode,
struct clock_event_device *evt)
{
u32 reg;
timer_writel(0, TIMER3_BASE + TIMER_PTV);
switch (mode) {
case CLOCK_EVT_MODE_PERIODIC:
reg = 0xC0000000 | ((1000000/HZ)-1);
timer_writel(reg, TIMER3_BASE + TIMER_PTV);
break;
case CLOCK_EVT_MODE_ONESHOT:
break;
case CLOCK_EVT_MODE_UNUSED:
case CLOCK_EVT_MODE_SHUTDOWN:
case CLOCK_EVT_MODE_RESUME:
break;
}
}
static struct clock_event_device tegra_clockevent = {
.name = "timer0",
.rating = 300,
.features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC,
.set_next_event = tegra_timer_set_next_event,
.set_mode = tegra_timer_set_mode,
};
static DEFINE_CLOCK_DATA(cd);
/*
* Constants generated by clocks_calc_mult_shift(m, s, 1MHz, NSEC_PER_SEC, 60).
* This gives a resolution of about 1us and a wrap period of about 1h11min.
*/
#define SC_MULT 4194304000u
#define SC_SHIFT 22
unsigned long long notrace sched_clock(void)
{
u32 cyc = timer_readl(TIMERUS_CNTR_1US);
return cyc_to_fixed_sched_clock(&cd, cyc, (u32)~0, SC_MULT, SC_SHIFT);
}
static void notrace tegra_update_sched_clock(void)
{
u32 cyc = timer_readl(TIMERUS_CNTR_1US);
update_sched_clock(&cd, cyc, (u32)~0);
}
/*
* tegra_rtc_read - Reads the Tegra RTC registers
* Care must be taken that this funciton is not called while the
* tegra_rtc driver could be executing to avoid race conditions
* on the RTC shadow register
*/
static u64 tegra_rtc_read_ms(void)
{
u32 ms = readl(rtc_base + RTC_MILLISECONDS);
u32 s = readl(rtc_base + RTC_SHADOW_SECONDS);
return (u64)s * MSEC_PER_SEC + ms;
}
/*
* read_persistent_clock - Return time from a persistent clock.
*
* Reads the time from a source which isn't disabled during PM, the
* 32k sync timer. Convert the cycles elapsed since last read into
* nsecs and adds to a monotonically increasing timespec.
* Care must be taken that this funciton is not called while the
* tegra_rtc driver could be executing to avoid race conditions
* on the RTC shadow register
*/
void read_persistent_clock(struct timespec *ts)
{
u64 delta;
struct timespec *tsp = &persistent_ts;
last_persistent_ms = persistent_ms;
persistent_ms = tegra_rtc_read_ms();
delta = persistent_ms - last_persistent_ms;
timespec_add_ns(tsp, delta * NSEC_PER_MSEC);
*ts = *tsp;
}
static irqreturn_t tegra_timer_interrupt(int irq, void *dev_id)
{
struct clock_event_device *evt = (struct clock_event_device *)dev_id;
timer_writel(1<<30, TIMER3_BASE + TIMER_PCR);
evt->event_handler(evt);
return IRQ_HANDLED;
}
static struct irqaction tegra_timer_irq = {
.name = "timer0",
.flags = IRQF_DISABLED | IRQF_TIMER | IRQF_TRIGGER_HIGH,
.handler = tegra_timer_interrupt,
.dev_id = &tegra_clockevent,
.irq = INT_TMR3,
};
static void __init tegra_init_timer(void)
{
struct clk *clk;
unsigned long rate = clk_measure_input_freq();
int ret;
clk = clk_get_sys("timer", NULL);
BUG_ON(IS_ERR(clk));
clk_enable(clk);
/*
* rtc registers are used by read_persistent_clock, keep the rtc clock
* enabled
*/
clk = clk_get_sys("rtc-tegra", NULL);
BUG_ON(IS_ERR(clk));
clk_enable(clk);
#ifdef CONFIG_HAVE_ARM_TWD
twd_base = IO_ADDRESS(TEGRA_ARM_PERIF_BASE + 0x600);
#endif
switch (rate) {
case 12000000:
timer_writel(0x000b, TIMERUS_USEC_CFG);
break;
case 13000000:
timer_writel(0x000c, TIMERUS_USEC_CFG);
break;
case 19200000:
timer_writel(0x045f, TIMERUS_USEC_CFG);
break;
case 26000000:
timer_writel(0x0019, TIMERUS_USEC_CFG);
break;
default:
WARN(1, "Unknown clock rate");
}
init_fixed_sched_clock(&cd, tegra_update_sched_clock, 32,
1000000, SC_MULT, SC_SHIFT);
if (clocksource_mmio_init(timer_reg_base + TIMERUS_CNTR_1US,
"timer_us", 1000000, 300, 32, clocksource_mmio_readl_up)) {
printk(KERN_ERR "Failed to register clocksource\n");
BUG();
}
ret = setup_irq(tegra_timer_irq.irq, &tegra_timer_irq);
if (ret) {
printk(KERN_ERR "Failed to register timer IRQ: %d\n", ret);
BUG();
}
clockevents_calc_mult_shift(&tegra_clockevent, 1000000, 5);
tegra_clockevent.max_delta_ns =
clockevent_delta2ns(0x1fffffff, &tegra_clockevent);
tegra_clockevent.min_delta_ns =
clockevent_delta2ns(0x1, &tegra_clockevent);
tegra_clockevent.cpumask = cpu_all_mask;
tegra_clockevent.irq = tegra_timer_irq.irq;
clockevents_register_device(&tegra_clockevent);
}
struct sys_timer tegra_timer = {
.init = tegra_init_timer,
};
#ifdef CONFIG_PM
static u32 usec_config;
void tegra_timer_suspend(void)
{
usec_config = timer_readl(TIMERUS_USEC_CFG);
}
void tegra_timer_resume(void)
{
timer_writel(usec_config, TIMERUS_USEC_CFG);
}
#endif
