uspace/libc/generic/time.c

   1 /*
   2  * Copyright (c) 2006 Ondrej Palkovsky
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * - Redistributions of source code must retain the above copyright
  10  *   notice, this list of conditions and the following disclaimer.
  11  * - Redistributions in binary form must reproduce the above copyright
  12  *   notice, this list of conditions and the following disclaimer in the
  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
  15  *   derived from this software without specific prior written permission.
  16  *
  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
  19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  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
  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
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 /** @addtogroup libc
  30  * @{
  31  */
  32 /** @file
  33  */
  34
  35 #include <sys/time.h>
  36 #include <unistd.h>
  37 #include <ipc/ipc.h>
  38 #include <stdio.h>
  39 #include <arch/barrier.h>
  40 #include <unistd.h>
  41 #include <atomic.h>
  42 #include <futex.h>
  43 #include <sysinfo.h>
  44 #include <ipc/services.h>
  45
  46 #include <sysinfo.h>
  47 #include <as.h>
  48 #include <ddi.h>
  49
  50 /* Pointers to public variables with time */
  51 struct {
  52         volatile sysarg_t seconds1;
  53         volatile sysarg_t useconds;
  54         volatile sysarg_t seconds2;
  55 } *ktime = NULL;
  56
  57
  58 /** POSIX gettimeofday
  59  *
  60  * The time variables are memory mapped(RO) from kernel, which updates
  61  * them periodically. As it is impossible to read 2 values atomically, we
  62  * use a trick: First read a seconds, then read microseconds, then
  63  * read seconds again. If a second elapsed in the meantime, set it to zero.
  64  * This provides assurance, that at least the
  65  * sequence of subsequent gettimeofday calls is ordered.
  66  */
  67 int gettimeofday(struct timeval *tv, struct timezone *tz)
  68 {
  69         void *mapping;
  70         sysarg_t s1, s2;
  71         sysarg_t rights;
  72         int res;
  73
  74         if (!ktime) {
  75                 mapping = as_get_mappable_page(PAGE_SIZE, (int)
  76                         sysinfo_value("clock.fcolor"));
  77                 /* Get the mapping of kernel clock */
  78                 res = ipc_call_sync_3(PHONE_NS, IPC_M_AS_AREA_RECV, (sysarg_t)
  79                         mapping, PAGE_SIZE, SERVICE_MEM_REALTIME, NULL, &rights,
  80                         NULL);
  81                 if (res) {
  82                         printf("Failed to initialize timeofday memarea\n");
  83                         _exit(1);
  84                 }
  85                 if (! (rights & AS_AREA_READ)) {
  86                         printf("Received bad rights on time area: %X\n",
  87                                rights);
  88                         as_area_destroy(mapping);
  89                         _exit(1);
  90                 }
  91                 ktime = mapping;
  92         }
  93         if (tz) {
  94                 tz->tz_minuteswest = 0;
  95                 tz->tz_dsttime = DST_NONE;
  96         }
  97
  98         s2 = ktime->seconds2;
  99         read_barrier();
 100         tv->tv_usec = ktime->useconds;
 101         read_barrier();
 102         s1 = ktime->seconds1;
 103         if (s1 != s2) {
 104                 tv->tv_usec = 0;
 105                 tv->tv_sec = s1 > s2 ? s1 : s2;
 106         } else
 107                 tv->tv_sec = s1;
 108
 109         return 0;
 110 }
 111
 112 /** Wait unconditionally for specified microseconds */
 113 void usleep(unsigned long usec)
 114 {
 115         atomic_t futex = FUTEX_INITIALIZER;
 116
 117         futex_initialize(&futex,0);
 118         futex_down_timeout(&futex, usec, 0);
 119 }
 120
 121 /** @}
 122  */