payloads/libpayload/libc/time.c

   1 /*
   2  *
   3  * Copyright (C) 2008 Advanced Micro Devices, Inc.
   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  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. The name of the author may not be used to endorse or promote products
  14  *    derived from this software without specific prior written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  */
  28
  29 /**
  30  * @file libc/time.c
  31  * General time functions
  32  */
  33
  34 #define __STDC_FORMAT_MACROS
  35
  36 #include <libpayload-config.h>
  37 #include <libpayload.h>
  38 #if CONFIG(LP_ARCH_X86) && CONFIG(LP_NVRAM)
  39 #include <arch/rdtsc.h>
  40 #endif
  41 #include <commonlib/bsd/gcd.h>
  42 #include <inttypes.h>
  43
  44 extern u32 cpu_khz;
  45
  46 static struct {
  47         u64 ticks;
  48         time_t secs;
  49         suseconds_t usecs;
  50 } clock;
  51
  52 static void update_clock(void)
  53 {
  54         u64 delta = timer_raw_value() - clock.ticks;
  55         int secs;
  56         static uint64_t ticks_per_sec = 0;
  57         static uint64_t ticks_per_usec = 0;
  58         if (!ticks_per_sec) {
  59                 ticks_per_sec = timer_hz();
  60                 ticks_per_usec = timer_hz() / 1000000;
  61         }
  62
  63         clock.ticks += delta;
  64
  65         secs = (int) (delta / ticks_per_sec);
  66         clock.secs += secs;
  67         delta -= (secs * ticks_per_sec);
  68         clock.usecs += (int)(delta / ticks_per_usec);
  69
  70         if (clock.usecs > 1000000) {
  71                 clock.usecs -= 1000000;
  72                 clock.secs++;
  73         }
  74 }
  75
  76 #if CONFIG(LP_NVRAM)
  77
  78 static unsigned int day_of_year(int mon, int day, int year)
  79 {
  80         static u8 mdays[12] = { 31, 28, 31, 30, 31, 30,
  81                                 31, 31, 30, 31, 30, 31 };
  82
  83         int i, ret = 0;
  84
  85         for(i = 0; i < mon; i++) {
  86                 ret += mdays[i];
  87
  88                 if (i == 1 && (year % 4))
  89                         ret++;
  90         }
  91
  92         return (ret + day);
  93 }
  94
  95 static void gettimeofday_init(void)
  96 {
  97         int days, delta;
  98         struct tm tm;
  99
 100         rtc_read_clock(&tm);
 101         clock.ticks = rdtsc();
 102
 103         /* Calculate the number of days in the year so far */
 104         days = day_of_year(tm.tm_mon, tm.tm_mday, tm.tm_year + 1900);
 105
 106         delta = tm.tm_year - 70;
 107
 108         days += (delta * 365);
 109
 110         /* Figure leap years */
 111
 112         if (delta > 2)
 113           days += (delta - 2) / 4;
 114
 115         clock.secs = (days * 86400) + (tm.tm_hour * 3600) +
 116                 (tm.tm_min * 60) + tm.tm_sec;
 117 }
 118 #else
 119 static void gettimeofday_init(void)
 120 {
 121         /* Record the number of ticks */
 122         clock.ticks = timer_raw_value();
 123 }
 124 #endif
 125
 126 /**
 127  * Return the current time expressed as seconds from 00:00:00 UTC, 1 Jan 1970.
 128  *
 129  * @param tp When not NULL, set this to the current time in seconds.
 130  * @return The current time in seconds.
 131  */
 132 time_t time(time_t *tp)
 133 {
 134         /*
 135          * Call the gtod init when we need it - this keeps the code from
 136          * being included in the binary if we don't need it.
 137          */
 138         if (!clock.ticks)
 139                 gettimeofday_init();
 140
 141         update_clock();
 142
 143         if (tp)
 144                 *tp = clock.secs;
 145
 146         return clock.secs;
 147 }
 148
 149 /**
 150  * Return the current time broken into a timeval structure.
 151  *
 152  * @param tv A pointer to a timeval structure.
 153  * @param tz Added for compatibility - not used.
 154  * @return 0 for success (this function cannot return non-zero currently).
 155  */
 156 int gettimeofday(struct timeval *tv, void *tz)
 157 {
 158         tv->tv_sec = time(NULL);
 159         tv->tv_usec = clock.usecs;
 160
 161         return 0;
 162 }
 163
 164 __attribute__((weak))
 165 void arch_ndelay(uint64_t ns)
 166 {
 167         uint64_t delta = ns * timer_hz() / NSECS_PER_SEC;
 168         uint64_t start = timer_raw_value();
 169         while (timer_raw_value() - start < delta) ;
 170 }
 171
 172 u64 timer_us(u64 base)
 173 {
 174         static u64 hz;
 175         static u32 mult = USECS_PER_SEC;
 176         u32 div;
 177
 178         // Only check timer_hz once. Assume it doesn't change.
 179         if (hz == 0) {
 180                 hz = timer_hz();
 181                 if (hz < mult) {
 182                         printf("Timer frequency %" PRIu64 " is too low, "
 183                                "must be at least 1MHz.\n", hz);
 184                         halt();
 185                 }
 186                 div = gcd(hz, mult);
 187                 hz /= div;
 188                 mult /= div;
 189         }
 190
 191         return (mult * timer_raw_value()) / hz - base;
 192 }