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Merge pull request #463 from LudwigOrtmann/native_hwtimer_fixup

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fix native hwtimer
This commit is contained in:
Christian Mehlis 2013-12-20 09:58:50 -08:00
commit f683771f11
1 changed files with 65 additions and 17 deletions
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82
cpu/native/hwtimer_cpu.c
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@ -31,6 +31,7 @@
#include <signal.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <err.h>
#include "hwtimer.h"
@ -56,6 +57,41 @@ static int native_hwtimer_isset[ARCH_MAXTIMERS];
static int next_timer = -1;
static void (*int_handler)(int);
/**
* Subtract the `struct timeval' values x and y, storing the result in
* result.
* Return 1 if the difference is negative, otherwise 0.
*
* Source:
* http://www.gnu.org/software/libc/manual/html_node/Elapsed-Time.html
*/
int timeval_subtract(struct timeval *result, struct timeval *x, struct timeval *y)
{
/* Perform the carry for the later subtraction by updating y. */
if (x->tv_usec < y->tv_usec) {
int nsec = (y->tv_usec - x->tv_usec) / 1000000 + 1;
y->tv_usec -= 1000000 * nsec;
y->tv_sec += nsec;
}
if (x->tv_usec - y->tv_usec > 1000000) {
int nsec = (x->tv_usec - y->tv_usec) / 1000000;
y->tv_usec += 1000000 * nsec;
y->tv_sec -= nsec;
}
/**
* Compute the time remaining to wait.
* tv_usec is certainly positive.
*/
result->tv_sec = x->tv_sec - y->tv_sec;
result->tv_usec = x->tv_usec - y->tv_usec;
/* Return 1 if result is negative. */
return x->tv_sec < y->tv_sec;
}
/**
* sets timeval to given ticks
*/
@ -114,8 +150,25 @@ void schedule_timer(void)
}
/* next pending timer is in slot next_timer */
if (setitimer(ITIMER_REAL, &native_hwtimer[next_timer], NULL) == -1) {
err(EXIT_FAILURE, "schedule_timer");
struct timeval now;
ticks2tv(native_hwtimer_now, &now);
struct itimerval result;
memset(&result, 0, sizeof(result));
int retval = timeval_subtract(&result.it_value, &native_hwtimer[next_timer].it_value, &now);
if (retval || (tv2ticks(&result.it_value) < HWTIMERMINOFFSET)) {
/* the timeout has happened already, schedule an interrupt */
int sig = SIGALRM;
if (real_write(_sig_pipefd[1], &sig, sizeof(int)) == -1) {
err(EXIT_FAILURE, "schedule_timer(): real_write()");
}
_native_sigpend++;
return;
}
if (setitimer(ITIMER_REAL, &result, NULL) == -1) {
err(EXIT_FAILURE, "schedule_timer: setitimer");
}
else {
DEBUG("schedule_timer(): set next timer (%i).\n", next_timer);
@ -184,19 +237,8 @@ void hwtimer_arch_set(unsigned long offset, short timer)
{
DEBUG("hwtimer_arch_set(%lu, \033[31m%i\033[0m)\n", offset, timer);
if (offset < HWTIMERMINOFFSET) {
offset = HWTIMERMINOFFSET;
DEBUG("hwtimer_arch_set: offset < MIN, set to: %lu\n", offset);
}
native_hwtimer_isset[timer] = 1;
ticks2tv(offset, &(native_hwtimer[timer].it_value));
DEBUG("hwtimer_arch_set(): that is %lu s %lu us from now\n",
(unsigned long)native_hwtimer[timer].it_value.tv_sec,
(unsigned long)native_hwtimer[timer].it_value.tv_usec);
schedule_timer();
offset += native_hwtimer_now;
hwtimer_arch_set_absolute(offset, timer);
return;
}
@ -204,9 +246,15 @@ void hwtimer_arch_set(unsigned long offset, short timer)
void hwtimer_arch_set_absolute(unsigned long value, short timer)
{
DEBUG("hwtimer_arch_set_absolute(%lu, %i)\n", value, timer);
value -= native_hwtimer_now;
hwtimer_arch_set(value, timer);
ticks2tv(value, &(native_hwtimer[timer].it_value));
DEBUG("hwtimer_arch_set_absolute(): that is %lu s %lu us from now\n",
(unsigned long)native_hwtimer[timer].it_value.tv_sec,
(unsigned long)native_hwtimer[timer].it_value.tv_usec);
native_hwtimer_isset[timer] = 1;
schedule_timer();
return;
}