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/* -*- mode: c; c-file-style: "bsd"; -*- */
/*
Copyright (C) 2001-2003 Paul Davis
Copyright (C) 2005 Jussi Laako
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include <config.h>
#include <stdint.h>
jack_time_t (*_jack_get_microseconds)(void) = 0;
#if defined(__gnu_linux__) && (defined(__i386__) || defined(__x86_64__))
#define HPET_SUPPORT
#define HPET_MMAP_SIZE 1024
#define HPET_CAPS 0x000
#define HPET_PERIOD 0x004
#define HPET_COUNTER 0x0f0
#define HPET_CAPS_COUNTER_64BIT (1 << 13)
#if defined(__x86_64__)
typedef uint64_t hpet_counter_t;
#else
typedef uint32_t hpet_counter_t;
#endif
static int hpet_fd;
static unsigned char *hpet_ptr;
static uint32_t hpet_period; /* period length in femto secs */
static uint64_t hpet_offset = 0;
static uint64_t hpet_wrap;
static hpet_counter_t hpet_previous = 0;
#endif /* defined(__gnu_linux__) && (__i386__ || __x86_64__) */
#ifdef HPET_SUPPORT
int
jack_hpet_init ()
{
uint32_t hpet_caps;
hpet_fd = open ("/dev/hpet", O_RDONLY);
if (hpet_fd < 0) {
jack_error ("This system has no accessible HPET device (%s)", strerror (errno));
return -1;
}
hpet_ptr = (unsigned char*)mmap (NULL, HPET_MMAP_SIZE,
PROT_READ, MAP_SHARED, hpet_fd, 0);
if (hpet_ptr == MAP_FAILED) {
jack_error ("This system has no mappable HPET device (%s)", strerror (errno));
close (hpet_fd);
return -1;
}
/* this assumes period to be constant. if needed,
it can be moved to the clock access function
*/
hpet_period = *((uint32_t*)(hpet_ptr + HPET_PERIOD));
hpet_caps = *((uint32_t*)(hpet_ptr + HPET_CAPS));
hpet_wrap = ((hpet_caps & HPET_CAPS_COUNTER_64BIT) &&
(sizeof(hpet_counter_t) == sizeof(uint64_t))) ?
0 : ((uint64_t)1 << 32);
return 0;
}
static jack_time_t
jack_get_microseconds_from_hpet (void)
{
hpet_counter_t hpet_counter;
long double hpet_time;
hpet_counter = *((hpet_counter_t*)(hpet_ptr + HPET_COUNTER));
if (unlikely (hpet_counter < hpet_previous)) {
hpet_offset += hpet_wrap;
}
hpet_previous = hpet_counter;
hpet_time = (long double)(hpet_offset + hpet_counter) *
(long double)hpet_period * (long double)1e-9;
return (jack_time_t)(hpet_time + 0.5);
}
#else
static int
jack_hpet_init ()
{
jack_error ("This version of JACK or this computer does not have HPET support.\n"
"Please choose a different clock source.");
return -1;
}
static jack_time_t
jack_get_microseconds_from_hpet (void)
{
/* never called */
return 0;
}
#endif /* HPET_SUPPORT */
void
jack_init_time ()
{
/* nothing to do on a generic system - we use the system clock */
}
void
jack_set_clock_source (jack_timer_type_t clocksrc)
{
switch (clocksrc) {
case JACK_TIMER_HPET:
if (jack_hpet_init () == 0) {
_jack_get_microseconds = jack_get_microseconds_from_hpet;
} else {
_jack_get_microseconds = jack_get_microseconds_from_system;
}
break;
case JACK_TIMER_SYSTEM_CLOCK:
default:
_jack_get_microseconds = jack_get_microseconds_from_system;
break;
}
}
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