just saw this from QEMU (vl.c) - on how its uses the HPET and RTC
timer (just a a brief extracts), and this is a userspace program,
assuming that the kernel has been compiled for it (CONFIG_HPET,
CONFIG_HPET_TIMER etc):
static int hpet_start_timer(struct qemu_alarm_timer *t)
{
struct hpet_info info;
int r, fd;
fd = open("/dev/hpet", O_RDONLY);
if (fd < 0)
return -1;
/* Set frequency */
r = ioctl(fd, HPET_IRQFREQ, RTC_FREQ);
if (r < 0) {
fprintf(stderr, "Could not configure '/dev/hpet' to have a
1024Hz timer. This is not a fatal\n"
"error, but for better emulation accuracy type:\n"
"'echo 1024 > /proc/sys/dev/hpet/max-user-freq' as root.\n");
goto fail;
}
/* Check capabilities */
r = ioctl(fd, HPET_INFO, &info);
if (r < 0)
goto fail;
/* Enable periodic mode */
r = ioctl(fd, HPET_EPI, 0);
if (info.hi_flags && (r < 0))
goto fail;
/* Enable interrupt */
r = ioctl(fd, HPET_IE_ON, 0);
if (r < 0)
goto fail;
enable_sigio_timer(fd);
t->priv = (void *)(long)fd;
return 0;
fail:
close(fd);
return -1;
}
static void hpet_stop_timer(struct qemu_alarm_timer *t)
{
int fd = (long)t->priv;
close(fd);
}
static int rtc_start_timer(struct qemu_alarm_timer *t)
{
int rtc_fd;
TFR(rtc_fd = open("/dev/rtc", O_RDONLY));
if (rtc_fd < 0)
return -1;
if (ioctl(rtc_fd, RTC_IRQP_SET, RTC_FREQ) < 0) {
fprintf(stderr, "Could not configure '/dev/rtc' to have a 1024
Hz timer. This is not a fatal\n"
"error, but for better emulation accuracy either use a
2.6 host Linux kernel or\n"
"type 'echo 1024 > /proc/sys/dev/rtc/max-user-freq' as
root.\n");
goto fail;
}
if (ioctl(rtc_fd, RTC_PIE_ON, 0) < 0) {
fail:
close(rtc_fd);
return -1;
}
enable_sigio_timer(rtc_fd);
t->priv = (void *)(long)rtc_fd;
return 0;
}
static void rtc_stop_timer(struct qemu_alarm_timer *t)
{
int rtc_fd = (long)t->priv;
close(rtc_fd);
}
Have fun!!!!
--
Regards,
Peter Teoh
--
To unsubscribe from this list: send an email with
"unsubscribe kernelnewbies" to [EMAIL PROTECTED]
Please read the FAQ at http://kernelnewbies.org/FAQ
