WebSVN – HelenOS-historic – Diff – /uspace/trunk/libc/generic/time.c


/*
 * Copyright (C) 2006 Ondrej Palkovsky
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
#include <sys/time.h>
#include <unistd.h>
#include <ipc/ipc.h>
#include <stdio.h>
#include <arch/barrier.h>
#include <unistd.h>
#include <atomic.h>
#include <futex.h>
 
#include <sysinfo.h>
#include <as.h>
#include <ddi.h>
 
/* Pointers to public variables with time */
struct {
    volatile sysarg_t seconds1;
    volatile sysarg_t useconds;
    volatile sysarg_t seconds2;
} *ktime = NULL;
 
 
/** POSIX gettimeofday
 *
 * The time variables are memory mapped(RO) from kernel, which updates
 * them periodically. As it is impossible to read 2 values atomically, we
 * use a trick: First read a seconds, then read microseconds, then
 * read seconds again. If a second elapsed in the meantime, read
 * useconds again. This provides assurance, that at least the
 * sequence of subsequent gettimeofday calls is ordered.
 */
 
int gettimeofday(struct timeval *tv, struct timezone *tz)
{
    void *mapping;
    sysarg_t s1, s2;
    sysarg_t rights;
    int res;
 
    if (!ktime) {
        mapping = as_get_mappable_page(PAGE_SIZE);
        /* Get the mapping of kernel clock */
        res = ipc_call_sync_3(PHONE_NS, IPC_M_AS_AREA_RECV,
 
                      mapping, PAGE_SIZE, 0,
 
                      NULL,&rights,NULL);
        if (res) {
            printf("Failed to initialize timeofday memarea\n");
            _exit(1);
        }
        if (rights != (AS_AREA_READ | AS_AREA_CACHEABLE)) {
            printf("Received bad rights on time area: %X\n",
                   rights);
            as_area_destroy(mapping);
            _exit(1);
        }
        ktime = mapping;
    }
    if (tz) {
        tz->tz_minuteswest = 0;
        tz->tz_dsttime = DST_NONE;
    }
 
    s2 = ktime->seconds2;
    read_barrier();
    tv->tv_usec = ktime->useconds;
    read_barrier();
    s1 = ktime->seconds1;
    if (s1 != s2) {
        tv->tv_usec = 0;
        tv->tv_sec = s1 > s2 ? s1 : s2;
    } else
        tv->tv_sec = s1;
 
    return 0;
}
 
/** Wait unconditionally for specified microseconds */
void usleep(unsigned long usec)
{
    atomic_t futex = FUTEX_INITIALIZER;
 
    futex_initialize(&futex,0);
    futex_down_timeout(&futex, usec, 0);
}
 

Rev 1462	Rev 1501
1	/*	1	/*
2	* Copyright (C) 2006 Ondrej Palkovsky	2	* Copyright (C) 2006 Ondrej Palkovsky
3	* All rights reserved.	3	* All rights reserved.
4	*	4	*
5	* Redistribution and use in source and binary forms, with or without	5	* Redistribution and use in source and binary forms, with or without
6	* modification, are permitted provided that the following conditions	6	* modification, are permitted provided that the following conditions
7	* are met:	7	* are met:
8	*	8	*
9	* - Redistributions of source code must retain the above copyright	9	* - Redistributions of source code must retain the above copyright
10	* notice, this list of conditions and the following disclaimer.	10	* notice, this list of conditions and the following disclaimer.
11	* - Redistributions in binary form must reproduce the above copyright	11	* - Redistributions in binary form must reproduce the above copyright
12	* notice, this list of conditions and the following disclaimer in the	12	* notice, this list of conditions and the following disclaimer in the
13	* documentation and/or other materials provided with the distribution.	13	* documentation and/or other materials provided with the distribution.
14	* - The name of the author may not be used to endorse or promote products	14	* - The name of the author may not be used to endorse or promote products
15	* derived from this software without specific prior written permission.	15	* derived from this software without specific prior written permission.
16	*	16	*
17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR	17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES	18	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.	19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,	20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT	21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,	22	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY	23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT	24	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF	25	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.	26	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27	*/	27	*/
28		28
29	#include <sys/time.h>	29	#include <sys/time.h>
30	#include <unistd.h>	30	#include <unistd.h>
31	#include <ipc/ipc.h>	31	#include <ipc/ipc.h>
32	#include <stdio.h>	32	#include <stdio.h>
33	#include <arch/barrier.h>	33	#include <arch/barrier.h>
34	#include <unistd.h>	34	#include <unistd.h>
35	#include <atomic.h>	35	#include <atomic.h>
36	#include <futex.h>	36	#include <futex.h>
37		37
38	#include <sysinfo.h>	38	#include <sysinfo.h>
39	#include <as.h>	39	#include <as.h>
40	#include <ddi.h>	40	#include <ddi.h>
41		41
42	/* Pointers to public variables with time */	42	/* Pointers to public variables with time */
43	struct {	43	struct {
44	volatile sysarg_t seconds1;	44	volatile sysarg_t seconds1;
45	volatile sysarg_t useconds;	45	volatile sysarg_t useconds;
46	volatile sysarg_t seconds2;	46	volatile sysarg_t seconds2;
47	} *ktime = NULL;	47	} *ktime = NULL;
48		48
49		49
50	/** POSIX gettimeofday	50	/** POSIX gettimeofday
51	*	51	*
52	* The time variables are memory mapped(RO) from kernel, which updates	52	* The time variables are memory mapped(RO) from kernel, which updates
53	* them periodically. As it is impossible to read 2 values atomically, we	53	* them periodically. As it is impossible to read 2 values atomically, we
54	* use a trick: First read a seconds, then read microseconds, then	54	* use a trick: First read a seconds, then read microseconds, then
55	* read seconds again. If a second elapsed in the meantime, read	55	* read seconds again. If a second elapsed in the meantime, read
56	* useconds again. This provides assurance, that at least the	56	* useconds again. This provides assurance, that at least the
57	* sequence of subsequent gettimeofday calls is ordered.	57	* sequence of subsequent gettimeofday calls is ordered.
58	*/	58	*/
59	#define TMAREA (10010241024)	-
60	int gettimeofday(struct timeval tv, struct timezone tz)	59	int gettimeofday(struct timeval tv, struct timezone tz)
61	{	60	{
62	void *mapping;	61	void *mapping;
63	sysarg_t s1, s2;	62	sysarg_t s1, s2;
64	sysarg_t rights;	63	sysarg_t rights;
65	int res;	64	int res;
66		65
67	if (!ktime) {	66	if (!ktime) {
68	/* TODO: specify better, where to map the area */	67	mapping = as_get_mappable_page(PAGE_SIZE);
69	/* Get the mapping of kernel clock */	68	/* Get the mapping of kernel clock */
70	res = ipc_call_sync_3(PHONE_NS, IPC_M_AS_AREA_RECV,	69	res = ipc_call_sync_3(PHONE_NS, IPC_M_AS_AREA_RECV,
71	TMAREA,	-
72	PAGE_SIZE,	70	mapping, PAGE_SIZE, 0,
73	0,	-
74	NULL,&rights,NULL);	71	NULL,&rights,NULL);
75	if (res) {	72	if (res) {
76	printf("Failed to initialize timeofday memarea\n");	73	printf("Failed to initialize timeofday memarea\n");
77	_exit(1);	74	_exit(1);
78	}	75	}
79	if (rights != (AS_AREA_READ \| AS_AREA_CACHEABLE)) {	76	if (rights != (AS_AREA_READ \| AS_AREA_CACHEABLE)) {
80	printf("Received bad rights on time area: %X\n",	77	printf("Received bad rights on time area: %X\n",
81	rights);	78	rights);
82	as_area_destroy(TMAREA);	79	as_area_destroy(mapping);
83	_exit(1);	80	_exit(1);
84	}	81	}
85	ktime = (void *) (TMAREA);	82	ktime = mapping;
86	}	83	}
87	if (tz) {	84	if (tz) {
88	tz->tz_minuteswest = 0;	85	tz->tz_minuteswest = 0;
89	tz->tz_dsttime = DST_NONE;	86	tz->tz_dsttime = DST_NONE;
90	}	87	}
91		88
92	s2 = ktime->seconds2;	89	s2 = ktime->seconds2;
93	read_barrier();	90	read_barrier();
94	tv->tv_usec = ktime->useconds;	91	tv->tv_usec = ktime->useconds;
95	read_barrier();	92	read_barrier();
96	s1 = ktime->seconds1;	93	s1 = ktime->seconds1;
97	if (s1 != s2) {	94	if (s1 != s2) {
98	tv->tv_usec = 0;	95	tv->tv_usec = 0;
99	tv->tv_sec = s1 > s2 ? s1 : s2;	96	tv->tv_sec = s1 > s2 ? s1 : s2;
100	} else	97	} else
101	tv->tv_sec = s1;	98	tv->tv_sec = s1;
102		99
103	return 0;	100	return 0;
104	}	101	}
105		102
106	/** Wait unconditionally for specified microseconds */	103	/** Wait unconditionally for specified microseconds */
107	void usleep(unsigned long usec)	104	void usleep(unsigned long usec)
108	{	105	{
109	atomic_t futex = FUTEX_INITIALIZER;	106	atomic_t futex = FUTEX_INITIALIZER;
110		107
111	futex_initialize(&futex,0);	108	futex_initialize(&futex,0);
112	futex_down_timeout(&futex, usec, 0);	109	futex_down_timeout(&futex, usec, 0);
113	}	110	}
114		111

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(root)/uspace/trunk/libc/generic/time.c – Rev 1462 → 1501