diff options
Diffstat (limited to 'common/timer.c')
-rw-r--r-- | common/timer.c | 278 |
1 files changed, 278 insertions, 0 deletions
diff --git a/common/timer.c b/common/timer.c new file mode 100644 index 0000000000..0256d673bc --- /dev/null +++ b/common/timer.c @@ -0,0 +1,278 @@ +/* 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 "uart.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 = 0; + +/* 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 = 31 - __builtin_clz(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); +} + +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) + ; +} + +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 interrupt: it would be slow, just do it on + * the next IT + */ +} + +void usleep(unsigned us) +{ + uint32_t evt = 0; + + /* 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)); + + /* 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; +} + +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); +} + +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\n" + "Deadline: 0x%016lx -> %11.6ld s from now\n" + "Active timers:\n", + 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(); + } + } +} + +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); + +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", + NULL); + +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_CONSOLE_COMMAND(gettime, command_get_time, + NULL, + "Print current time", + NULL); + +int command_timer_info(int argc, char **argv) +{ + timer_print_info(); + + return EC_SUCCESS; +} +DECLARE_CONSOLE_COMMAND(timerinfo, command_timer_info, + NULL, + "Print timer info", + NULL); |