drivers/timer.h

   1 /* Taken from Etherboot */
   2 /* Defines for routines to implement a low-overhead timer for drivers */
   3
   4  /*
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License as
   7  * published by the Free Software Foundation; either version 2, or (at
   8  * your option) any later version.
   9  */
  10
  11 #ifndef TIMER_H
  12 #define TIMER_H
  13
  14 /* Ports for the 8254 timer chip */
  15 #define TIMER2_PORT     0x42
  16 #define TIMER_MODE_PORT 0x43
  17
  18 /* Meaning of the mode bits */
  19 #define TIMER0_SEL      0x00
  20 #define TIMER1_SEL      0x40
  21 #define TIMER2_SEL      0x80
  22 #define READBACK_SEL    0xC0
  23
  24 #define LATCH_COUNT     0x00
  25 #define LOBYTE_ACCESS   0x10
  26 #define HIBYTE_ACCESS   0x20
  27 #define WORD_ACCESS     0x30
  28
  29 #define MODE0           0x00
  30 #define MODE1           0x02
  31 #define MODE2           0x04
  32 #define MODE3           0x06
  33 #define MODE4           0x08
  34 #define MODE5           0x0A
  35
  36 #define BINARY_COUNT    0x00
  37 #define BCD_COUNT       0x01
  38
  39 /* Timers tick over at this rate */
  40 #define CLOCK_TICK_RATE 1193180U
  41 #define TICKS_PER_MS    (CLOCK_TICK_RATE/1000)
  42
  43 /* Parallel Peripheral Controller Port B */
  44 #define PPC_PORTB       0x61
  45
  46 /* Meaning of the port bits */
  47 #define PPCB_T2OUT      0x20    /* Bit 5 */
  48 #define PPCB_SPKR       0x02    /* Bit 1 */
  49 #define PPCB_T2GATE     0x01    /* Bit 0 */
  50
  51 extern void setup_timers(void);
  52 extern void ndelay(unsigned int nsecs);
  53 extern void udelay(unsigned int usecs);
  54 extern void mdelay(unsigned int msecs);
  55 extern unsigned long currticks(void);
  56 extern unsigned long get_timer_freq(void);
  57
  58 #define TICKS_PER_SEC 1000
  59
  60 #endif  /* TIMER_H */