drivers/timer.c

   1 /*
   2  *   OpenBIOS native timer driver
   3  *
   4  *   (C) 2004 Stefan Reinauer <stepan@openbios.org>
   5  *
   6  *   This program is free software; you can redistribute it and/or
   7  *   modify it under the terms of the GNU General Public License
   8  *   version 2
   9  *
  10  */
  11
  12 #include "config.h"
  13 #include "timer.h"
  14 #include "asm/io.h"
  15
  16 #if defined(CONFIG_X86) || defined(CONFIG_AMD64)
  17
  18 void setup_timers(void)
  19 {
  20         /* nothing to do */
  21 }
  22
  23 static void load_timer2(unsigned int ticks)
  24 {
  25         /* Set up the timer gate, turn off the speaker */
  26         outb((inb(PPC_PORTB) & ~PPCB_SPKR) | PPCB_T2GATE, PPC_PORTB);
  27         outb(TIMER2_SEL | WORD_ACCESS | MODE0 | BINARY_COUNT,
  28              TIMER_MODE_PORT);
  29         outb(ticks & 0xFF, TIMER2_PORT);
  30         outb(ticks >> 8, TIMER2_PORT);
  31 }
  32
  33 void udelay(unsigned int usecs)
  34 {
  35         load_timer2((usecs * TICKS_PER_MS) / 1000);
  36         while ((inb(PPC_PORTB) & PPCB_T2OUT) == 0);
  37 }
  38
  39 unsigned long currticks(void)
  40 {
  41         static unsigned long totticks = 0UL;    /* High resolution */
  42         unsigned long ticks = 0;
  43         unsigned char portb = inb(PPC_PORTB);
  44
  45         /*
  46          * Read the timer, and hope it hasn't wrapped around
  47          * (call this again within 54ms), then restart it
  48          */
  49         outb(TIMER2_SEL | LATCH_COUNT, TIMER_MODE_PORT);
  50         ticks = inb(TIMER2_PORT);
  51         ticks |= inb(TIMER2_PORT) << 8;
  52         outb(TIMER2_SEL | WORD_ACCESS | MODE0 | BINARY_COUNT,
  53              TIMER_MODE_PORT);
  54         outb(0, TIMER2_PORT);
  55         outb(0, TIMER2_PORT);
  56
  57         /*
  58          * Check if the timer was running. If not,
  59          * result is rubbish and need to start it
  60          */
  61         if (portb & PPCB_T2GATE) {
  62                 totticks += (0x10000 - ticks);
  63         } else {
  64                 /* Set up the timer gate, turn off the speaker */
  65                 outb((portb & ~PPCB_SPKR) | PPCB_T2GATE, PPC_PORTB);
  66         }
  67         return totticks / TICKS_PER_MS;
  68 }
  69 #endif
  70
  71 #ifdef CONFIG_PPC
  72
  73 void setup_timers(void)
  74 {
  75         /* nothing to do */
  76 }
  77
  78 /*
  79  * TODO: pass via lb table
  80  */
  81
  82 unsigned long get_timer_freq(void)
  83 {
  84         return 10000000 / 4;
  85 }
  86
  87 void udelay(unsigned int usecs)
  88 {
  89         extern void _wait_ticks(unsigned long);
  90         unsigned long ticksperusec = get_timer_freq() / 1000000;
  91         _wait_ticks(ticksperusec * usecs);
  92 }
  93
  94 #endif
  95
  96 void ndelay(unsigned int nsecs)
  97 {
  98         udelay((nsecs + 999) / 1000);
  99 }
 100
 101 void mdelay(unsigned int msecs)
 102 {
 103         udelay(msecs * 1000);
 104 }