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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 */
#include "atomic.h"
#include "console.h"
#include "hooks.h"
#include "hwtimer.h"
#include "system.h"
#include "util.h"
#include "task.h"
#include "timer.h"
#define TIMER_SYSJUMP_TAG 0x4d54 /* "TM" */
/* High word of the 64-bit timestamp counter */
static volatile uint32_t clksrc_high;
/* Bitmap of currently running timers */
static uint32_t timer_running;
/* Deadlines of all timers */
static timestamp_t timer_deadline[TASK_ID_COUNT];
static uint32_t next_deadline = 0xffffffff;
/* Hardware timer routine IRQ number */
static int timer_irq;
static void expire_timer(task_id_t tskid)
{
/* we are done with this timer */
atomic_clear(&timer_running, 1 << tskid);
/* wake up the taks waiting for this timer */
task_set_event(tskid, TASK_EVENT_TIMER, 0);
}
int timestamp_expired(timestamp_t deadline, const timestamp_t *now)
{
timestamp_t now_val;
if (!now) {
now_val = get_time();
now = &now_val;
}
return ((int64_t)(now->val - deadline.val) >= 0);
}
void process_timers(int overflow)
{
uint32_t check_timer, running_t0;
timestamp_t next;
timestamp_t now;
if (overflow)
clksrc_high++;
do {
next.val = -1ull;
now = get_time();
do {
/* read atomically the current state of timer running */
check_timer = running_t0 = timer_running;
while (check_timer) {
int tskid = __fls(check_timer);
/* timer has expired ? */
if (timer_deadline[tskid].val <= now.val)
expire_timer(tskid);
else if ((timer_deadline[tskid].le.hi ==
now.le.hi) &&
(timer_deadline[tskid].le.lo <
next.le.lo))
next.val = timer_deadline[tskid].val;
check_timer &= ~(1 << tskid);
}
/* if there is a new timer, let's retry */
} while (timer_running & ~running_t0);
if (next.le.hi == 0xffffffff) {
/* no deadline to set */
__hw_clock_event_clear();
next_deadline = 0xffffffff;
return;
}
__hw_clock_event_set(next.le.lo);
next_deadline = next.le.lo;
} while (next.val <= get_time().val);
}
#ifndef CONFIG_HW_SPECIFIC_UDELAY
void udelay(unsigned us)
{
unsigned t0 = __hw_clock_source_read();
/*
* udelay() may be called with interrupts disabled, so we can't rely on
* process_timers() updating the top 32 bits. So handle wraparound
* ourselves rather than calling get_time() and comparing with a
* deadline.
*
* This may fail for delays close to 2^32 us (~4000 sec), because the
* subtraction below can overflow. That's acceptable, because the
* watchdog timer would have tripped long before that anyway.
*/
while (__hw_clock_source_read() - t0 <= us)
;
}
#endif
int timer_arm(timestamp_t tstamp, task_id_t tskid)
{
ASSERT(tskid < TASK_ID_COUNT);
if (timer_running & (1<<tskid))
return EC_ERROR_BUSY;
timer_deadline[tskid] = tstamp;
atomic_or(&timer_running, 1<<tskid);
/* Modify the next event if needed */
if ((tstamp.le.hi < clksrc_high) ||
((tstamp.le.hi == clksrc_high) && (tstamp.le.lo <= next_deadline)))
task_trigger_irq(timer_irq);
return EC_SUCCESS;
}
void timer_cancel(task_id_t tskid)
{
ASSERT(tskid < TASK_ID_COUNT);
atomic_clear(&timer_running, 1 << tskid);
/*
* Don't need to cancel the hardware timer interrupt, instead do
* timer-related housekeeping when the next timer interrupt fires.
*/
}
/*
* For us < (2^31 - task scheduling latency)(~ 2147 sec), this function will
* sleep for at least us, and no more than 2*us. As us approaches 2^32-1, the
* probability of delay longer than 2*us (and possibly infinite delay)
* increases.
*/
void usleep(unsigned us)
{
uint32_t evt = 0;
uint32_t t0 = __hw_clock_source_read();
/* If task scheduling has not started, just delay */
if (!task_start_called()) {
udelay(us);
return;
}
ASSERT(us);
do {
evt |= task_wait_event(us);
} while (!(evt & TASK_EVENT_TIMER) &&
((__hw_clock_source_read() - t0) < us));
/* Re-queue other events which happened in the meanwhile */
if (evt)
atomic_or(task_get_event_bitmap(task_get_current()),
evt & ~TASK_EVENT_TIMER);
}
timestamp_t get_time(void)
{
timestamp_t ts;
ts.le.hi = clksrc_high;
ts.le.lo = __hw_clock_source_read();
if (ts.le.hi != clksrc_high) {
ts.le.hi = clksrc_high;
ts.le.lo = __hw_clock_source_read();
}
return ts;
}
clock_t clock(void)
{
/* __hw_clock_source_read() returns a microsecond resolution timer.*/
return (clock_t) __hw_clock_source_read() / 1000;
}
void force_time(timestamp_t ts)
{
clksrc_high = ts.le.hi;
__hw_clock_source_set(ts.le.lo);
/* some timers might be already expired : process them */
task_trigger_irq(timer_irq);
}
#ifdef CONFIG_CMD_TIMERINFO
void timer_print_info(void)
{
uint64_t t = get_time().val;
uint64_t deadline = (uint64_t)clksrc_high << 32 |
__hw_clock_event_get();
int tskid;
ccprintf("Time: 0x%016lx us, %11.6ld s\n"
"Deadline: 0x%016lx -> %11.6ld s from now\n"
"Active timers:\n",
t, t, deadline, deadline - t);
cflush();
for (tskid = 0; tskid < TASK_ID_COUNT; tskid++) {
if (timer_running & (1<<tskid)) {
ccprintf(" Tsk %2d 0x%016lx -> %11.6ld\n", tskid,
timer_deadline[tskid].val,
timer_deadline[tskid].val - t);
cflush();
}
}
}
#else
void timer_print_info(void) { }
#endif
void timer_init(void)
{
const timestamp_t *ts;
int size, version;
BUILD_ASSERT(TASK_ID_COUNT < sizeof(timer_running) * 8);
/* Restore time from before sysjump */
ts = (const timestamp_t *)system_get_jump_tag(TIMER_SYSJUMP_TAG,
&version, &size);
if (ts && version == 1 && size == sizeof(timestamp_t)) {
clksrc_high = ts->le.hi;
timer_irq = __hw_clock_source_init(ts->le.lo);
} else {
clksrc_high = 0;
timer_irq = __hw_clock_source_init(0);
}
}
/* Preserve time across a sysjump */
static void timer_sysjump(void)
{
timestamp_t ts = get_time();
system_add_jump_tag(TIMER_SYSJUMP_TAG, 1, sizeof(ts), &ts);
}
DECLARE_HOOK(HOOK_SYSJUMP, timer_sysjump, HOOK_PRIO_DEFAULT);
#ifdef CONFIG_CMD_WAITMS
static int command_wait(int argc, char **argv)
{
char *e;
int i;
if (argc < 2)
return EC_ERROR_PARAM_COUNT;
i = strtoi(argv[1], &e, 0);
if (*e)
return EC_ERROR_PARAM1;
udelay(i * 1000);
return EC_SUCCESS;
}
DECLARE_CONSOLE_COMMAND(waitms, command_wait,
"msec",
"Busy-wait for msec");
#endif
#ifdef CONFIG_CMD_FORCETIME
static int command_force_time(int argc, char **argv)
{
char *e;
timestamp_t new;
if (argc < 3)
return EC_ERROR_PARAM_COUNT;
new.le.hi = strtoi(argv[1], &e, 0);
if (*e)
return EC_ERROR_PARAM1;
new.le.lo = strtoi(argv[2], &e, 0);
if (*e)
return EC_ERROR_PARAM2;
ccprintf("Time: 0x%016lx = %.6ld s\n", new.val, new.val);
force_time(new);
return EC_SUCCESS;
}
DECLARE_CONSOLE_COMMAND(forcetime, command_force_time,
"hi lo",
"Force current time");
#endif
static int command_get_time(int argc, char **argv)
{
timestamp_t ts = get_time();
ccprintf("Time: 0x%016lx = %.6ld s\n", ts.val, ts.val);
return EC_SUCCESS;
}
DECLARE_SAFE_CONSOLE_COMMAND(gettime, command_get_time,
NULL,
"Print current time");
#ifdef CONFIG_CMD_TIMERINFO
int command_timer_info(int argc, char **argv)
{
timer_print_info();
return EC_SUCCESS;
}
DECLARE_SAFE_CONSOLE_COMMAND(timerinfo, command_timer_info,
NULL,
"Print timer info");
#endif
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