diff options
Diffstat (limited to 'package/openwrt/libshared/linux_timer.c')
-rw-r--r-- | package/openwrt/libshared/linux_timer.c | 707 |
1 files changed, 707 insertions, 0 deletions
diff --git a/package/openwrt/libshared/linux_timer.c b/package/openwrt/libshared/linux_timer.c new file mode 100644 index 0000000000..eece9f84e8 --- /dev/null +++ b/package/openwrt/libshared/linux_timer.c @@ -0,0 +1,707 @@ +/* + * Copyright 2004, Broadcom Corporation + * All Rights Reserved. + * + * THIS SOFTWARE IS OFFERED "AS IS", AND BROADCOM GRANTS NO WARRANTIES OF ANY + * KIND, EXPRESS OR IMPLIED, BY STATUTE, COMMUNICATION OR OTHERWISE. BROADCOM + * SPECIFICALLY DISCLAIMS ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS + * FOR A SPECIFIC PURPOSE OR NONINFRINGEMENT CONCERNING THIS SOFTWARE. + * + * Low resolution timer interface linux specific implementation. + * + * $Id$ + */ + +/* +* debug facilities +*/ +#define TIMER_DEBUG 0 +#if TIMER_DEBUG +#define TIMERDBG(fmt, args...) printf("%s: " fmt "\n" , __FUNCTION__ , ## args) +#else +#define TIMERDBG(fmt, args...) +#endif + + +/* + * POSIX timer support for Linux. Taken from linux_timer.c in upnp + */ + +#define __USE_GNU + + +#include <stdlib.h> // for malloc, free, etc. +#include <string.h> // for memset, strncasecmp, etc. +#include <assert.h> // for assert, of course. +#include <signal.h> // for sigemptyset, etc. +#include <stdio.h> // for printf, etc. +#include <sys/time.h> +#include <time.h> + +/* define TIMER_PROFILE to enable code which guages how accurate the timer functions are. + For each expiring timer the code will print the expected time interval and the actual time interval. +#define TIMER_PROFILE +*/ +#undef TIMER_PROFILE + +/* +timer_cancel( ) - cancel a timer +timer_connect( ) - connect a user routine to the timer signal +timer_create( ) - allocate a timer using the specified clock for a timing base (POSIX) +timer_delete( ) - remove a previously created timer (POSIX) +timer_gettime( ) - get the remaining time before expiration and the reload value (POSIX) +timer_getoverrun( ) - return the timer expiration overrun (POSIX) +timer_settime( ) - set the time until the next expiration and arm timer (POSIX) +nanosleep( ) - suspend the current task until the time interval elapses (POSIX) +*/ + +#define MS_PER_SEC 1000 +#define US_PER_SEC 1000000 +#define US_PER_MS 1000 +#define UCLOCKS_PER_SEC 1000000 + +typedef void (*event_callback_t)(timer_t, int); + +#ifndef TIMESPEC_TO_TIMEVAL +# define TIMESPEC_TO_TIMEVAL(tv, ts) { \ + (tv)->tv_sec = (ts)->tv_sec; \ + (tv)->tv_usec = (ts)->tv_nsec / 1000; \ +} +#endif + +#ifndef TIMEVAL_TO_TIMESPEC +# define TIMEVAL_TO_TIMESPEC(tv, ts) { \ + (ts)->tv_sec = (tv)->tv_sec; \ + (ts)->tv_nsec = (tv)->tv_usec * 1000; \ +} +#endif + +#define ROUNDUP(x,y) ((((x)+(y)-1)/(y))*(y)) + +#define timerroundup(t,g) \ + do { \ + if (!timerisset(t)) (t)->tv_usec=1; \ + if ((t)->tv_sec == 0) (t)->tv_usec=ROUNDUP((t)->tv_usec, g); \ + } while (0) + +typedef long uclock_t; + +#define TFLAG_NONE 0 +#define TFLAG_CANCELLED (1<<0) +#define TFLAG_DELETED (1<<1) + +struct event { + struct timeval it_interval; + struct timeval it_value; + event_callback_t func; + int arg; + unsigned short flags; + struct event *next; +#ifdef TIMER_PROFILE + uint expected_ms; + uclock_t start; +#endif +}; + +void timer_cancel(timer_t timerid); + +static void alarm_handler(int i); +static void check_event_queue(); +static void print_event_queue(); +static void check_timer(); +#if THIS_FINDS_USE +static int count_queue(struct event *); +#endif + +void block_timer(); +void unblock_timer(); + +static struct event *event_queue = NULL; +static struct event *event_freelist; +static uint g_granularity; +static int g_maxevents = 0; + +uclock_t uclock() +{ + struct timeval tv; + + gettimeofday(&tv, NULL); + return ((tv.tv_sec * US_PER_SEC) + tv.tv_usec); +} + + +void init_event_queue(int n) +{ + int i; + struct itimerval tv; + + g_maxevents = n; + event_freelist = (struct event *) malloc(n * sizeof(struct event)); + memset(event_freelist, 0, n * sizeof(struct event)); + + for (i = 0; i < (n-1); i++) + event_freelist[i].next = &event_freelist[i+1]; + + event_freelist[i].next = NULL; + + tv.it_interval.tv_sec = 0; + tv.it_interval.tv_usec = 1; + tv.it_value.tv_sec = 0; + tv.it_value.tv_usec = 0; + setitimer (ITIMER_REAL, &tv, 0); + setitimer (ITIMER_REAL, 0, &tv); + g_granularity = tv.it_interval.tv_usec; + + signal(SIGALRM, alarm_handler); +} + + +int clock_gettime( + clockid_t clock_id, /* clock ID (always CLOCK_REALTIME) */ + struct timespec * tp /* where to store current time */ +) +{ + struct timeval tv; + int n; + + + n = gettimeofday(&tv, NULL); + TIMEVAL_TO_TIMESPEC(&tv, tp); + + return n; +} + + +int timer_create( + clockid_t clock_id, /* clock ID (always CLOCK_REALTIME) */ + struct sigevent * evp, /* user event handler */ + timer_t * pTimer /* ptr to return value */ +) +{ + struct event *event; + + if (clock_id != CLOCK_REALTIME) { + TIMERDBG("timer_create can only support clock id CLOCK_REALTIME"); + exit(1); + } + + if (evp != NULL) { + if (evp->sigev_notify != SIGEV_SIGNAL || evp->sigev_signo != SIGALRM) { + TIMERDBG("timer_create can only support signalled alarms using SIGALRM"); + exit(1); + } + } + + event = event_freelist; + if (event == NULL) { + print_event_queue(); + } + assert(event != NULL); + + event->flags = TFLAG_NONE; + + event_freelist = event->next; + event->next = NULL; + + check_event_queue(); + + *pTimer = (timer_t) event; + + return 0; +} + +int timer_delete( + timer_t timerid /* timer ID */ +) +{ + struct event *event = (struct event *) timerid; + + if (event->flags & TFLAG_DELETED) { + TIMERDBG("Cannot delete a deleted event"); + return 1; + } + + timer_cancel(timerid); + + event->flags |= TFLAG_DELETED; + + event->next = event_freelist; + event_freelist = event; + + return 0; +} + +int timer_connect +( + timer_t timerid, /* timer ID */ + void (*routine)(timer_t, int), /* user routine */ + int arg /* user argument */ +) +{ + struct event *event = (struct event *) timerid; + + assert(routine != NULL); + event->func = routine; + event->arg = arg; + + return 0; +} + + +int timer_settime +( + timer_t timerid, /* timer ID */ + int flags, /* absolute or relative */ + const struct itimerspec * value, /* time to be set */ + struct itimerspec * ovalue /* previous time set (NULL=no result) */ +) +{ + struct itimerval itimer; + struct event *event = (struct event *) timerid; + struct event **ppevent; + + TIMESPEC_TO_TIMEVAL(&event->it_interval, &value->it_interval); + TIMESPEC_TO_TIMEVAL(&event->it_value, &value->it_value); + + /* if .it_value is zero, the timer is disarmed */ + if (!timerisset(&event->it_value)) { + timer_cancel(timerid); + return 0; + } + + block_timer(); + +#ifdef TIMER_PROFILE + event->expected_ms = (event->it_value.tv_sec * MS_PER_SEC) + (event->it_value.tv_usec / US_PER_MS); + event->start = uclock(); +#endif + if (event->next) { + TIMERDBG("calling timer_settime with a timer that is already on the queue."); + } + + + /* We always want to make sure that the event at the head of the + queue has a timeout greater than the itimer granularity. + Otherwise we end up with the situation that the time remaining + on an itimer is greater than the time at the head of the queue + in the first place. */ + timerroundup(&event->it_value, g_granularity); + + timerclear(&itimer.it_value); + getitimer(ITIMER_REAL, &itimer); + if (timerisset(&itimer.it_value)) { + // reset the top timer to have an interval equal to the remaining interval + // when the timer was cancelled. + if (event_queue) { + if (timercmp(&(itimer.it_value), &(event_queue->it_value), >)) { + // it is an error if the amount of time remaining is more than the amount of time + // requested by the top event. + // + TIMERDBG("timer_settime: TIMER ERROR!"); + + } else { + // some portion of the top event has already expired. + // Reset the interval of the top event to remaining + // time left in that interval. + // + event_queue->it_value = itimer.it_value; + + // if we were the earliest timer before now, we are still the earliest timer now. + // we do not need to reorder the list. + } + } + } + + // Now, march down the list, decrementing the new timer by the + // current it_value of each event on the queue. + ppevent = &event_queue; + while (*ppevent) { + if ( timercmp(&(event->it_value), &((*ppevent)->it_value), <) ) { + // if the proposed event will trigger sooner than the next event + // in the queue, we will insert the new event just before the next one. + // + // we also need to adjust the delta value to the next event. + timersub(&((*ppevent)->it_value), &(event->it_value), &((*ppevent)->it_value)); + break; + } + // subtract the interval of the next event from the proposed interval. + timersub(&(event->it_value), &((*ppevent)->it_value), &(event->it_value)); + + ppevent = &((*ppevent)->next); + } + + // we have found our proper place in the queue, + // link our new event into the pending event queue. + event->next = *ppevent; + *ppevent = event; + + check_event_queue(); + + // if our new event ended up at the front of the queue, reissue the timer. + if (event == event_queue) { + timerroundup(&event_queue->it_value, g_granularity); + timerclear(&itimer.it_interval); + itimer.it_value = event_queue->it_value; + + // we want to be sure to never turn off the timer completely, + // so if the next interval is zero, set it to some small value. + if (!timerisset(&(itimer.it_value))) + itimer.it_value = (struct timeval) { 0, 1 }; + + assert(!timerisset(&itimer.it_interval)); + assert(itimer.it_value.tv_sec > 0 || itimer.it_value.tv_usec >= g_granularity); + assert(event_queue->it_value.tv_sec > 0 || event_queue->it_value.tv_usec >= g_granularity); + setitimer(ITIMER_REAL, &itimer, NULL); + check_timer(); + } + + event->flags &= ~TFLAG_CANCELLED; + + unblock_timer(); + + return 0; +} + +static void check_timer() +{ + struct itimerval itimer; + + getitimer(ITIMER_REAL, &itimer); + if (timerisset(&itimer.it_interval)) { + TIMERDBG("ERROR timer interval is set."); + } + if (timercmp(&(itimer.it_value), &(event_queue->it_value), >)) { + TIMERDBG("ERROR timer expires later than top event."); + } +} + + +static void check_event_queue() +{ + struct timeval sum; + struct event *event; + int i = 0; + +#ifdef notdef + int nfree = 0; + struct event *p; + for (p = event_freelist; p; p = p->next) + nfree++; + printf("%d free events\n", nfree); +#endif + + timerclear(&sum); + for (event = event_queue; event; event = event->next) { + if (i > g_maxevents) { + TIMERDBG("timer queue looks like it loops back on itself!"); + print_event_queue(); + exit(1); + } + i++; + } +} + +#if THIS_FINDS_USE +/* The original upnp version has this unused function, so I left it in + to maintain the resemblance. */ +static int count_queue(struct event *event_queue) +{ + struct event *event; + int i = 0; + for (event = event_queue; event; event = event->next) + i++; + return i; +} +#endif + +static void print_event_queue() +{ + struct event *event; + int i = 0; + + for (event = event_queue; event; event = event->next) { + printf("#%d (0x%x)->0x%x: \t%d sec %d usec\t%p\n", + i++, (unsigned int) event, (unsigned int) event->next, (int) event->it_value.tv_sec, (int) event->it_value.tv_usec, event->func); + if (i > g_maxevents) { + printf("...(giving up)\n"); + break; + } + } +} + +// The top element of the event queue must have expired. +// Remove that element, run its function, and reset the timer. +// if there is no interval, recycle the event structure. +static void alarm_handler(int i) +{ + struct event *event, **ppevent; + struct itimerval itimer; + struct timeval small_interval = { 0, g_granularity/2 }; +#ifdef TIMER_PROFILE + uint junk; + uclock_t end; + uint actual; +#endif + + block_timer(); + + // Loop through the event queue and remove the first event plus any + // subsequent events that will expire very soon thereafter (within 'small_interval'}. + // + do { + // remove the top event. + event = event_queue; + event_queue = event_queue->next; + event->next = NULL; + +#ifdef TIMER_PROFILE + end = uclock(); + actual = ((end-event->start)/((uclock_t)UCLOCKS_PER_SEC/1000)); + if (actual < 0) + junk = end; + TIMERDBG("expected %d ms actual %d ms", event->expected_ms, ((end-event->start)/((uclock_t)UCLOCKS_PER_SEC/1000))); +#endif + + // call the event callback function + (*(event->func))((timer_t) event, (int)event->arg); + + /* If the event has been cancelled, do NOT put it back on the queue. */ + if ( !(event->flags & TFLAG_CANCELLED) ) { + + // if the event is a recurring event, reset the timer and + // find its correct place in the sorted list of events. + // + if (timerisset(&event->it_interval)) { + // event is recurring... + // + event->it_value = event->it_interval; +#ifdef TIMER_PROFILE + event->expected_ms = (event->it_value.tv_sec * MS_PER_SEC) + (event->it_value.tv_usec / US_PER_MS); + event->start = uclock(); +#endif + timerroundup(&event->it_value, g_granularity); + + // Now, march down the list, decrementing the new timer by the + // current delta of each event on the queue. + ppevent = &event_queue; + while (*ppevent) { + if ( timercmp(&(event->it_value), &((*ppevent)->it_value), <) ) { + // if the proposed event will trigger sooner than the next event + // in the queue, we will insert the new event just before the next one. + // + // we also need to adjust the delta value to the next event. + timersub(&((*ppevent)->it_value), &(event->it_value), &((*ppevent)->it_value)); + break; + } + timersub(&(event->it_value), &((*ppevent)->it_value), &(event->it_value)); + ppevent = &((*ppevent)->next); + } + + // we have found our proper place in the queue, + // link our new event into the pending event queue. + event->next = *ppevent; + *ppevent = event; + } else { + // there is no interval, so recycle the event structure. + //timer_delete((timer_t) event); + } + } + + check_event_queue(); + + } while (event_queue && timercmp(&event_queue->it_value, &small_interval, <)); + + // re-issue the timer... + if (event_queue) { + timerroundup(&event_queue->it_value, g_granularity); + + timerclear(&itimer.it_interval); + itimer.it_value = event_queue->it_value; + // we want to be sure to never turn off the timer completely, + // so if the next interval is zero, set it to some small value. + if (!timerisset(&(itimer.it_value))) + itimer.it_value = (struct timeval) { 0, 1 }; + + setitimer(ITIMER_REAL, &itimer, NULL); + check_timer(); + } else { + TIMERDBG("There are no events in the queue - timer not reset."); + } + + unblock_timer(); +} + +static int block_count = 0; + +void block_timer() +{ + sigset_t set; + + if (block_count++ == 0) { + sigemptyset(&set); + sigaddset(&set, SIGALRM); + sigprocmask(SIG_BLOCK, &set, NULL); + } +} + +void unblock_timer() +{ + sigset_t set; + + if (--block_count == 0) { + sigemptyset(&set); + sigaddset(&set, SIGALRM); + sigprocmask(SIG_UNBLOCK, &set, NULL); + } +} + +void timer_cancel_all() +{ + struct itimerval timeroff = { { 0, 0 }, { 0, 0} }; + struct event *event; + struct event **ppevent; + + setitimer(ITIMER_REAL, &timeroff, NULL); + + ppevent = &event_queue; + while (*ppevent) { + event = *ppevent; + *ppevent = event->next; + event->next = NULL; + } +} + + + +void timer_cancel(timer_t timerid) +{ + struct itimerval itimer; + struct itimerval timeroff = { { 0, 0 }, { 0, 0} }; + struct event *event = (struct event *) timerid; + struct event **ppevent; + + if (event->flags & TFLAG_CANCELLED) { + TIMERDBG("Cannot cancel a cancelled event"); + return; + } + + block_timer(); + + ppevent = &event_queue; + while (*ppevent) { + if ( *ppevent == event ) { + + /* RACE CONDITION - if the alarm goes off while we are in + this loop, and if the timer we want to cancel is the + next to expire, the alarm will end up firing + after this routine is complete, causing it to go off early. */ + + /* If the cancelled timer is the next to expire, + we need to do something special to clean up correctly. */ + if (event == event_queue && event->next != NULL) { + timerclear(&itimer.it_value); + getitimer(ITIMER_REAL, &itimer); + + /* subtract the time that has already passed while waiting for this timer... */ + timersub(&(event->it_value), &(itimer.it_value), &(event->it_value)); + + /* and add any remainder to the next timer in the list */ + timeradd(&(event->next->it_value), &(event->it_value), &(event->next->it_value)); + } + + *ppevent = event->next; + event->next = NULL; + + if (event_queue) { + timerroundup(&event_queue->it_value, g_granularity); + timerclear(&itimer.it_interval); + itimer.it_value = event_queue->it_value; + + /* We want to be sure to never turn off the timer + completely if there are more events on the queue, + so if the next interval is zero, set it to some + small value. */ + + if (!timerisset(&(itimer.it_value))) + itimer.it_value = (struct timeval) { 0, 1 }; + + assert(itimer.it_value.tv_sec > 0 || itimer.it_value.tv_usec >= g_granularity); + assert(event_queue->it_value.tv_sec > 0 || event_queue->it_value.tv_usec >= g_granularity); + setitimer(ITIMER_REAL, &itimer, NULL); + check_timer(); + } else { + setitimer(ITIMER_REAL, &timeroff, NULL); + } + break; + } + ppevent = &((*ppevent)->next); + } + + event->flags |= TFLAG_CANCELLED; + + unblock_timer(); +} + +/* +* timer related headers +*/ +#include "bcmtimer.h" + +/* +* locally used global variables and constants +*/ + +/* +* Initialize internal resources used in the timer module. It must be called +* before any other timer function calls. The param 'timer_entries' is used +* to pre-allocate fixed number of timer entries. +*/ +int bcm_timer_module_init(int timer_entries, bcm_timer_module_id *module_id) +{ + init_event_queue(timer_entries); + *module_id = (bcm_timer_module_id)event_freelist; + return 0; +} + +/* +* Cleanup internal resources used by this timer module. It deletes all +* pending timer entries from the backend timer system as well. +*/ +int bcm_timer_module_cleanup(bcm_timer_module_id module_id) +{ + module_id = 0; + return 0; +} + +int bcm_timer_create(bcm_timer_module_id module_id, bcm_timer_id *timer_id) +{ + module_id = 0; + return timer_create(CLOCK_REALTIME, NULL, (timer_t *)timer_id); +} + +int bcm_timer_delete(bcm_timer_id timer_id) +{ + return timer_delete((timer_t)timer_id); +} + +int bcm_timer_gettime(bcm_timer_id timer_id, struct itimerspec *timer_spec) +{ + return -1; +} + +int bcm_timer_settime(bcm_timer_id timer_id, const struct itimerspec *timer_spec) +{ + return timer_settime((timer_t)timer_id, 0, timer_spec, NULL); +} + +int bcm_timer_connect(bcm_timer_id timer_id, bcm_timer_cb func, int data) +{ + return timer_connect((timer_t)timer_id, (void *)func, data); +} + +int bcm_timer_cancel(bcm_timer_id timer_id) +{ + timer_cancel((timer_t)timer_id); + return 0; +} + |