include/arch/x86/time/i8254.h

   1 #ifndef X86_I8254_H
   2 #define X86_I8254_H
   3
   4 #include <stdint.h>
   5 #include <io.h>
   6 #include <irq/i8259a.h>
   7
   8 /* for setting reload value and reading current count */
   9 #define PORT_CHANNEL_0_DATA     0x40
  10 #define PORT_CHANNEL_1_DATA     0x41
  11 #define PORT_CHANNEL_2_DATA     0x42
  12
  13 /* for configuring the channels */
  14 #define PORT_MODE_CMD_REG       0x43
  15
  16 /* operating modes */
  17 #define INT_ON_TERM_CNT         0x0
  18 #define HW_RETRIGGER_ONESHOT    0x1
  19 #define RATE_GENERATOR          0x2
  20 #define SQUARE_WAVE_GENERATOR   0x3
  21 #define SW_TRIGGERED_STROBE     0x4
  22 #define HW_TRIGGERED_STROBE     0x5
  23
  24 /* access modes */
  25 #define ACMODE_COUNTER_LATCH_CMD        0x0
  26 #define ACMODE_LSB_ONLY                 0x1
  27 #define ACMODE_MSB_ONLY                 0x2
  28 #define ACMODE_LSB_MSB                  0x3
  29
  30 union mode_command {
  31         struct {
  32                 unsigned bcd: 1, /* if set, uses BCD for reload value */
  33                          opmode: 3, /* operating mode */
  34                          acmode: 2, /* access mode */
  35                          channel: 2; /* channel to configure */
  36         } fields;
  37         uint8_t command;
  38 };
  39
  40 extern unsigned int ticks;
  41 extern uint16_t reload;
  42
  43 extern void i8254_configure_channel(char channel, char opmode, uint16_t new_reload);
  44 extern void i8254_irq_enable();
  45
  46 #endif