src/include/pc80/i8254.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2
   3 #ifndef PC80_I8254_H
   4 #define PC80_I8254_H
   5
   6 /* Ports for the 8254 timer chip */
   7 #define TIMER0_PORT     0x40
   8 #define TIMER1_PORT     0x41
   9 #define TIMER2_PORT     0x42
  10 #define TIMER_MODE_PORT 0x43
  11
  12 /* Meaning of the mode bits */
  13 #define TIMER0_SEL      0x00
  14 #define TIMER1_SEL      0x40
  15 #define TIMER2_SEL      0x80
  16 #define READBACK_SEL    0xC0
  17
  18 #define LATCH_COUNT     0x00
  19 #define LOBYTE_ACCESS   0x10
  20 #define HIBYTE_ACCESS   0x20
  21 #define WORD_ACCESS     0x30
  22
  23 #define MODE0           0x00
  24 #define MODE1           0x02
  25 #define MODE2           0x04
  26 #define MODE3           0x06
  27 #define MODE4           0x08
  28 #define MODE5           0x0A
  29
  30 #define BINARY_COUNT    0x00
  31 #define BCD_COUNT       0x01
  32
  33 /* Timers tick over at this rate */
  34 #define TICKS_PER_MS    1193
  35
  36 /* Parallel Peripheral Controller Port B */
  37 #define PPC_PORTB       0x61
  38
  39 /* Meaning of the port bits */
  40 #define PPCB_T2OUT      0x20    /* Bit 5 */
  41 #define PPCB_SPKR       0x02    /* Bit 1 */
  42 #define PPCB_T2GATE     0x01    /* Bit 0 */
  43
  44 void setup_i8254(void);
  45 unsigned long calibrate_tsc_with_pit(void);
  46 void beep(unsigned int frequency_hz, unsigned int duration_msec);
  47
  48 #endif /* PC80_I8254_H */