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/* Copyright (c) 2014 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
/* Hardware timers driver */
#include "clock.h"
#include "clock_chip.h"
#include "common.h"
#include "hooks.h"
#include "hwtimer.h"
#include "hwtimer_chip.h"
#include "registers.h"
#include "task.h"
#include "timer.h"
/* (2^TICK_ITIM_DEPTH us) between 2 ticks of timer */
#define TICK_ITIM_DEPTH 16 /* Depth of ITIM Unit: bits */
#define TICK_INTERVAL (1 << TICK_ITIM_DEPTH) /* Unit: us */
#define TICK_INTERVAL_MASK (TICK_INTERVAL - 1) /* Mask of interval */
#define TICK_ITIM_MAX_CNT (TICK_INTERVAL - 1) /* Maximum counter value */
/* 32-bits counter value */
static volatile uint32_t cur_cnt_us;
static volatile uint32_t pre_cnt_us;
/* Time when event will be expired unit:us */
static volatile uint32_t evt_expired_us;
/* 32-bits event counter */
static volatile uint32_t evt_cnt;
/* Debugger information */
#if DEBUG_TMR
static volatile uint32_t evt_cnt_us_dbg;
static volatile uint32_t cur_cnt_us_dbg;
#endif
/*****************************************************************************/
/* Internal functions */
void init_hw_timer(int itim_no, enum ITIM16_SOURCE_CLOCK_T source)
{
/* Use internal 32K clock/APB2 for ITIM16 */
UPDATE_BIT(NPCX_ITCTS(itim_no), NPCX_ITIM16_CKSEL,
source != ITIM16_SOURCE_CLOCK_APB2);
/* Clear timeout status */
SET_BIT(NPCX_ITCTS(itim_no), NPCX_ITIM16_TO_STS);
/* ITIM timeout interrupt enable */
SET_BIT(NPCX_ITCTS(itim_no), NPCX_ITIM16_TO_IE);
/* ITIM timeout wake-up enable */
SET_BIT(NPCX_ITCTS(itim_no), NPCX_ITIM16_TO_WUE);
}
/*****************************************************************************/
/* HWTimer event handlers */
void __hw_clock_event_set(uint32_t deadline)
{
float inv_evt_tick = INT_32K_CLOCK/(float)SECOND;
uint32_t evt_cnt_us;
/* Is deadline min value? */
if (evt_expired_us != 0 && evt_expired_us < deadline)
return;
/* mark min event value */
evt_expired_us = deadline;
evt_cnt_us = deadline - __hw_clock_source_read();
#if DEBUG_TMR
evt_cnt_us_dbg = deadline - __hw_clock_source_read();
#endif
/* Event module disable */
CLEAR_BIT(NPCX_ITCTS(ITIM_EVENT_NO), NPCX_ITIM16_ITEN);
/*
* ITIM count down : event expired : Unit: 1/32768 sec
* It must exceed evt_expired_us for process_timers function
*/
evt_cnt = ((uint32_t)(evt_cnt_us*inv_evt_tick)+1)-1;
if (evt_cnt > TICK_ITIM_MAX_CNT)
evt_cnt = TICK_ITIM_MAX_CNT;
NPCX_ITCNT16(ITIM_EVENT_NO) = evt_cnt;
/* Event module enable */
SET_BIT(NPCX_ITCTS(ITIM_EVENT_NO), NPCX_ITIM16_ITEN);
/* Enable interrupt of ITIM */
task_enable_irq(ITIM16_INT(ITIM_EVENT_NO));
}
/* Returns the time-stamp of the next programmed event */
uint32_t __hw_clock_event_get(void)
{
return evt_expired_us;
}
/* Returns time delay cause of deep idle */
uint32_t __hw_clock_get_sleep_time(void)
{
float evt_tick = SECOND/(float)INT_32K_CLOCK;
uint32_t sleep_time;
uint32_t cnt = NPCX_ITCNT16(ITIM_EVENT_NO);
interrupt_disable();
/* Event has been triggered but timer ISR dosen't handle it */
if (IS_BIT_SET(NPCX_ITCTS(ITIM_EVENT_NO), NPCX_ITIM16_TO_STS))
sleep_time = (uint32_t) (evt_cnt+1)*evt_tick;
/* Event hasn't been triggered */
else
sleep_time = (uint32_t) (evt_cnt+1 - cnt)*evt_tick;
interrupt_enable();
return sleep_time;
}
/* Cancel the next event programmed by __hw_clock_event_set */
void __hw_clock_event_clear(void)
{
/* ITIM event module disable */
CLEAR_BIT(NPCX_ITCTS(ITIM_EVENT_NO), NPCX_ITIM16_ITEN);
/* Disable interrupt of Event */
task_disable_irq(ITIM16_INT(ITIM_EVENT_NO));
/* Clear event parameters */
evt_expired_us = 0;
evt_cnt = 0;
}
/* Irq for hwtimer event */
void __hw_clock_event_irq(void)
{
int delay;
/* Clear timeout status for event */
SET_BIT(NPCX_ITCTS(ITIM_EVENT_NO), NPCX_ITIM16_TO_STS);
/* ITIM event module disable */
CLEAR_BIT(NPCX_ITCTS(ITIM_EVENT_NO), NPCX_ITIM16_ITEN);
/* Disable interrupt of event */
task_disable_irq(ITIM16_INT(ITIM_EVENT_NO));
/* Workaround for tick interrupt latency */
delay = evt_expired_us - __hw_clock_source_read();
if (delay > 0)
cur_cnt_us += delay;
/* Clear event parameters */
evt_expired_us = 0;
evt_cnt = 0;
/* handle upper driver */
process_timers(0);
}
DECLARE_IRQ(ITIM16_INT(ITIM_EVENT_NO) , __hw_clock_event_irq, 1);
/*****************************************************************************/
/* HWTimer tick handlers */
/* Returns the value of the free-running counter used as clock. */
uint32_t __hw_clock_source_read(void)
{
uint32_t us;
uint32_t cnt = NPCX_ITCNT16(ITIM_TIME_NO);
/* Is timeout expired? - but timer ISR dosen't handle it */
if (IS_BIT_SET(NPCX_ITCTS(ITIM_TIME_NO), NPCX_ITIM16_TO_STS))
us = TICK_INTERVAL;
else
us = TICK_INTERVAL - cnt;
#if DEBUG_TMR
cur_cnt_us_dbg = cur_cnt_us + us;
#endif
return cur_cnt_us + us;
}
/* Override the current value of the hardware counter */
void __hw_clock_source_set(uint32_t ts)
{
/* Set current time */
cur_cnt_us = ts;
}
/* Irq for hwtimer tick */
void __hw_clock_source_irq(void)
{
/* Is timeout trigger trigger? */
if (IS_BIT_SET(NPCX_ITCTS(ITIM_TIME_NO), NPCX_ITIM16_TO_STS)) {
/* Clear timeout status*/
SET_BIT(NPCX_ITCTS(ITIM_TIME_NO), NPCX_ITIM16_TO_STS);
/* Store previous time counter value */
pre_cnt_us = cur_cnt_us;
/* Increase TICK_INTERVAL unit:us */
cur_cnt_us += TICK_INTERVAL;
/* Is 32-bits timer count overflow? */
if (pre_cnt_us > cur_cnt_us)
process_timers(1);
} else { /* Handle soft trigger */
process_timers(0);
}
}
DECLARE_IRQ(NPCX_IRQ_ITIM16_1, __hw_clock_source_irq, 1);
static void update_prescaler(void)
{
/*
* prescaler to time tick
* Ttick_unit = (PRE_8+1) * Tapb2_clk
* PRE_8 = (Ttick_unit/Tapb2_clk) -1
*/
NPCX_ITPRE(ITIM_TIME_NO) = (clock_get_apb2_freq() / SECOND) - 1;
/* Set event tick unit = 1/32768 sec */
NPCX_ITPRE(ITIM_EVENT_NO) = 0;
}
DECLARE_HOOK(HOOK_FREQ_CHANGE, update_prescaler, HOOK_PRIO_DEFAULT);
int __hw_clock_source_init(uint32_t start_t)
{
/*
* 1. Use ITIM16-1 as internal time reading
* 2. Use ITIM16-2 for event handling
*/
/* Enable clock for ITIM peripheral */
clock_enable_peripheral(CGC_OFFSET_TIMER, CGC_TIMER_MASK,
CGC_MODE_RUN | CGC_MODE_SLEEP);
/* init tick & event timer first */
init_hw_timer(ITIM_TIME_NO, ITIM16_SOURCE_CLOCK_APB2);
init_hw_timer(ITIM_EVENT_NO, ITIM16_SOURCE_CLOCK_32K);
/* Set initial prescaler */
update_prescaler();
/* ITIM count down : TICK_INTERVAL expired*/
NPCX_ITCNT16(ITIM_TIME_NO) = TICK_ITIM_MAX_CNT;
/*
* Override the count with the start value now that counting has
* started.
*/
__hw_clock_source_set(start_t);
/* ITIM module enable */
SET_BIT(NPCX_ITCTS(ITIM_TIME_NO), NPCX_ITIM16_ITEN);
/* Enable interrupt of ITIM */
task_enable_irq(ITIM16_INT(ITIM_TIME_NO));
return ITIM16_INT(ITIM_TIME_NO);
}
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