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/* Copyright (c) 2012 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.
*/
/* Timer module for Chrome EC operating system */
#ifndef __CROS_EC_TIMER_H
#define __CROS_EC_TIMER_H
#include "common.h"
#include "task_id.h"
/* Microsecond timestamp. */
typedef union {
uint64_t val;
struct {
uint32_t lo;
uint32_t hi;
} le /* little endian words */;
} timestamp_t;
/* Initializes the Timer module. */
int timer_init(void);
/* Launch a one-shot timer for task <tskid> which expires at timestamp
* <tstamp>. */
int timer_arm(timestamp_t tstamp, task_id_t tskid);
/* Cancel a running timer for the specified task id. */
int timer_cancel(task_id_t tskid);
/**
* Check if a timestamp has passed / expired
*
* @param deadline deadline timer value to check
* @param now pointer to value of time_now() if known, else NULL
* @return 0 if deadline has not yet passed, 1 if it has passed
*/
int timestamp_expired(timestamp_t deadline, const timestamp_t *now);
/* Busy-wait the selected number of microseconds. Note that calling this
* with us>1000 may impact system performance; use usleep for longer delays. */
void udelay(unsigned us);
/* Sleep during the selected number of microseconds. The current task will be
* de-scheduled until the delay expires.
*
* Note: if an event happens before the end of sleep, the function will return.
*/
void usleep(unsigned us);
/* Get the current timestamp from the system timer. */
timestamp_t get_time(void);
/* Print the current timer information using the command output channel. This
* may be called from interrupt level. */
void timer_print_info(void);
/**
* Returns the number of microseconds that have elapsed from a start time.
*
* This function is for timing short delays typically of a few milliseconds
* or so.
*
* Note that this is limited to a maximum of 32 bits, which is around an
* hour. After that, the value returned will wrap.
*
* @param start Start time to compare against
* @return number of microseconds that have elspsed since that start time
*/
static inline unsigned time_since32(timestamp_t start)
{
return get_time().le.lo - start.le.lo;
}
#endif /* __CROS_EC_TIMER_H */
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