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/*
* Copyright (C) ST-Ericsson SA 2010
*
* License Terms: GNU General Public License v2
* Author: Rabin Vincent <rabin.vincent@stericsson.com>
*
*/
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/io.h>
#include <linux/clockchips.h>
#include <linux/delay.h>
#include <asm/smp.h>
#include <asm/mach/time.h>
#define RATE_32K 32768
#define LATCH_32K ((RATE_32K + HZ/2) / HZ)
#define WRITE_DELAY 130 /* in us */
#define WRITE_DELAY_32KHZ_TICKS ((WRITE_DELAY * RATE_32K) / 1000000)
#define RTT_IMSC 0x04
#define RTT_ICR 0x10
#define RTT_DR 0x14
#define RTT_LR 0x18
#define RTT_CR 0x1C
#define RTT_CR_RTTEN (1 << 1)
#define RTT_CR_RTTOS (1 << 0)
#define RTC_IMSC 0x10
#define RTC_RIS 0x14
#define RTC_MIS 0x18
#define RTC_ICR 0x1C
#define RTC_TDR 0x20
#define RTC_TLR1 0x24
#define RTC_TCR 0x28
#define RTC_TCR_RTTOS (1 << 0)
#define RTC_TCR_RTTEN (1 << 1)
#define RTC_TCR_RTTSS (1 << 2)
#define RTC_IMSC_TIMSC (1 << 1)
#define RTC_ICR_TIC (1 << 1)
static void __iomem *rtc_base;
static void rtc_writel(unsigned long val, unsigned long addr)
{
writel(val, rtc_base + addr);
}
static unsigned long rtc_readl(unsigned long addr)
{
return readl(rtc_base + addr);
}
static void rtc_set_mode(enum clock_event_mode mode,
struct clock_event_device *evt)
{
switch (mode) {
case CLOCK_EVT_MODE_PERIODIC:
rtc_writel(RTC_TCR_RTTSS, RTC_TCR);
rtc_writel(LATCH_32K, RTC_TLR1);
break;
case CLOCK_EVT_MODE_ONESHOT:
rtc_writel(0, RTC_TCR);
break;
case CLOCK_EVT_MODE_UNUSED:
case CLOCK_EVT_MODE_SHUTDOWN:
rtc_writel(0, RTC_TCR);
break;
case CLOCK_EVT_MODE_RESUME:
break;
}
}
static int rtc_set_event(unsigned long delta,
struct clock_event_device *dev)
{
rtc_writel(RTC_TCR_RTTOS, RTC_TCR);
udelay(WRITE_DELAY);
/*
* Compensate for the time that it takes to start the
* timer
*/
if (delta > WRITE_DELAY_32KHZ_TICKS * 2)
delta -= WRITE_DELAY_32KHZ_TICKS * 2;
else
delta = 1;
rtc_writel(delta, RTC_TLR1);
udelay(WRITE_DELAY);
rtc_writel(RTC_TCR_RTTOS | RTC_TCR_RTTEN, RTC_TCR);
udelay(WRITE_DELAY);
return 0;
}
static irqreturn_t rtc_interrupt(int irq, void *dev)
{
struct clock_event_device *clkevt = dev;
/* we make sure if this is our rtt isr */
if (rtc_readl(RTC_MIS) & 0x2) {
rtc_writel(RTC_ICR_TIC, RTC_ICR);
clkevt->event_handler(clkevt);
return IRQ_HANDLED;
}
return IRQ_NONE;
}
/*
* Added here as asm/smp.h is removed in v2.6.34 and
* this funcitons is needed for current PM setup.
*/
#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
void smp_timer_broadcast(const struct cpumask *mask);
#endif
static struct clock_event_device rtc_dev = {
.name = "rtc-rtt",
.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
.shift = 32,
.rating = 300,
.set_next_event = rtc_set_event,
.set_mode = rtc_set_mode,
#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
.broadcast = smp_timer_broadcast,
#endif
.cpumask = cpu_all_mask,
};
static struct irqaction rtc_irq = {
.name = "RTC-RTT Timer Tick",
.flags = IRQF_DISABLED | IRQF_TIMER | IRQF_SHARED,
.handler = rtc_interrupt,
.dev_id = &rtc_dev,
};
void rtc_rtt_timer_init(unsigned int cpu)
{
int irq;
if (cpu_is_u8500()) {
rtc_base = __io_address(U8500_RTC_BASE);
irq = IRQ_DB8500_RTC;
} else if (cpu_is_u5500()) {
rtc_base = __io_address(U5500_RTC_BASE);
irq = IRQ_DB5500_RTC;
} else {
pr_err("timer-rtt: Unknown DB Asic!\n");
return;
}
rtc_dev.irq = irq;
rtc_writel(0, RTC_TCR);
rtc_writel(RTC_ICR_TIC, RTC_ICR);
rtc_writel(RTC_IMSC_TIMSC, RTC_IMSC);
rtc_dev.mult = div_sc(RATE_32K, NSEC_PER_SEC, rtc_dev.shift);
rtc_dev.max_delta_ns = clockevent_delta2ns(0xffffffff, &rtc_dev);
rtc_dev.min_delta_ns = clockevent_delta2ns(0xff, &rtc_dev);
setup_irq(irq, &rtc_irq);
clockevents_register_device(&rtc_dev);
}
int rtc_rtt_adjust_next_wakeup(int delta_in_us)
{
int delta_ticks;
u64 temp;
u64 remainder;
u32 val;
/* Convert us to 32768 hz ticks */
temp = ((u64)abs(delta_in_us)) * RATE_32K;
remainder = do_div(temp, 1000000);
if (delta_in_us < 0) {
delta_ticks = - ((int) temp);
/* Round upwards, since better to wake a little early */
if ( remainder >= (1000000 / 2))
delta_ticks--;
} else {
delta_ticks = (int) temp;
}
val = readl(rtc_base + RTC_TDR);
/*
* Make sure that if we want to wake up earlier that it is
* possible.
*/
if ((int)val < -delta_ticks)
return -EINVAL;
/* Make sure we can wake up as late as requested */
if (((u64)val + (u64)delta_ticks) > UINT_MAX)
return -EINVAL;
return rtc_set_event(val + delta_ticks, &rtc_dev);
}
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