/*
* 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/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 <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/sched_clock.h>
#include <asm/mach/time.h>
#include <asm/smp_twd.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;
static void __iomem *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 u64 notrace tegra_read_sched_clock(void)
{
return timer_readl(TIMERUS_CNTR_1US);
}
/*
* 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;
}
/*
* tegra_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
*/
static void tegra_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_TIMER | IRQF_TRIGGER_HIGH,
.handler = tegra_timer_interrupt,
.dev_id = &tegra_clockevent,
};
static void __init tegra20_init_timer(struct device_node *np)
{
struct clk *clk;
unsigned long rate;
int ret;
timer_reg_base = of_iomap(np, 0);
if (!timer_reg_base) {
pr_err("Can't map timer registers\n");
BUG();
}
tegra_timer_irq.irq = irq_of_parse_and_map(np, 2);
if (tegra_timer_irq.irq <= 0) {
pr_err("Failed to map timer IRQ\n");
BUG();
}
clk = of_clk_get(np, 0);
if (IS_ERR(clk)) {
pr_warn("Unable to get timer clock. Assuming 12Mhz input clock.\n");
rate = 12000000;
} else {
clk_prepare_enable(clk);
rate = clk_get_rate(clk);
}
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");
}
sched_clock_register(tegra_read_sched_clock, 32, 1000000);
if (clocksource_mmio_init(timer_reg_base + TIMERUS_CNTR_1US,
"timer_us", 1000000, 300, 32, clocksource_mmio_readl_up)) {
pr_err("Failed to register clocksource\n");
BUG();
}
ret = setup_irq(tegra_timer_irq.irq, &tegra_timer_irq);
if (ret) {
pr_err("Failed to register timer IRQ: %d\n", ret);
BUG();
}
tegra_clockevent.cpumask = cpu_all_mask;
tegra_clockevent.irq = tegra_timer_irq.irq;
clockevents_config_and_register(&tegra_clockevent, 1000000,
0x1, 0x1fffffff);
}
CLOCKSOURCE_OF_DECLARE(tegra20_timer, "nvidia,tegra20-timer", tegra20_init_timer);
static void __init tegra20_init_rtc(struct device_node *np)
{
struct clk *clk;
rtc_base = of_iomap(np, 0);
if (!rtc_base) {
pr_err("Can't map RTC registers");
BUG();
}
/*
* rtc registers are used by read_persistent_clock, keep the rtc clock
* enabled
*/
clk = of_clk_get(np, 0);
if (IS_ERR(clk))
pr_warn("Unable to get rtc-tegra clock\n");
else
clk_prepare_enable(clk);
register_persistent_clock(NULL, tegra_read_persistent_clock);
}
CLOCKSOURCE_OF_DECLARE(tegra20_rtc, "nvidia,tegra20-rtc", tegra20_init_rtc);
#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