src/system/kernel/arch/x86/timers/pit.h

   1 /*
   2  * Copyright 2008, Dustin Howett, dustin.howett@gmail.com. All rights reserved.
   3  * Distributed under the terms of the MIT License.
   4  */
   5 #ifndef _KERNEL_ARCH_x86_TIMERS_PIT_H
   6 #define _KERNEL_ARCH_x86_TIMERS_PIT_H
   7
   8 #include <SupportDefs.h>
   9
  10 /* ports */
  11 #define PIT_CTRL        0x43
  12 #define PIT_CNT0        0x40
  13 #define PIT_CNT1        0x41
  14 #define PIT_CNT2        0x42
  15
  16 /* commands */
  17 #define PIT_SELCH0      0x00
  18 #define PIT_SELCH1      0x40
  19 #define PIT_SELCH2      0x80
  20
  21 #define PIT_RWLOW       0x10
  22 #define PIT_RWHIGH      0x20
  23 #define PIT_RWBOTH      0x30
  24
  25 #define PIT_MD_INTON0   0x00
  26 #define PIT_MD_ONESHOT  0x02
  27 #define PIT_MD_RTGEN    0x04
  28 #define PIT_MD_SQGEN    0x06
  29 #define PIT_MD_SW_STRB  0x08
  30 #define PIT_MD_HW_STRB  0x0A
  31
  32 #define PIT_BCD         0x01
  33
  34 #define PIT_LATCH       0x00
  35
  36 #define PIT_READ        0xF0
  37 #define PIT_CNT         0x20
  38 #define PIT_STAT        0x10
  39
  40 #define PIT_CLOCK_RATE  1193180
  41 #define PIT_MAX_TIMER_INTERVAL (0xffff * 1000000ll / PIT_CLOCK_RATE)
  42
  43 /* Method Prototypes */
  44 static int pit_get_prio(void);
  45 static status_t pit_set_hardware_timer(bigtime_t relativeTimeout);
  46 static status_t pit_clear_hardware_timer(void);
  47 static status_t pit_init(struct kernel_args *args);
  48
  49 #endif /* _KERNEL_ARCH_x86_TIMERS_PIT_H */