src/lib/timer.c

   1 /*
   2  * This file is part of the coreboot project.
   3  *
   4  * Copyright 2014 Google Inc.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; version 2 of the License.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  */
  15
  16 #include <console/console.h>
  17 #include <timer.h>
  18 #include <delay.h>
  19 #include <thread.h>
  20
  21 __attribute__((weak)) void init_timer() { /* do nothing */ }
  22
  23 void udelay(unsigned usec)
  24 {
  25         struct stopwatch sw;
  26
  27         /*
  28          * As the timer granularity is in microseconds pad the
  29          * requested delay by one to get at least >= requested usec delay.
  30          */
  31         usec += 1;
  32
  33         if (!thread_yield_microseconds(usec))
  34                 return;
  35
  36         stopwatch_init_usecs_expire(&sw, usec);
  37
  38         while (!stopwatch_expired(&sw))
  39                 ;
  40 }