1 /* 2 * This file is subject to the terms and conditions of the GNU General Public 3 * License. See the file "COPYING" in the main directory of this archive 4 * for more details. 5 * 6 * Machine specific IO port address definition for generic. 7 * Written by Osamu Tomita <tomita@cinet.co.jp> 8 */ 9 #ifndef __LINUX_I8253_H 10 #define __LINUX_I8253_H 11 12 #include <linux/param.h> 13 #include <linux/spinlock.h> 14 #include <linux/timex.h> 15 16 /* i8253A PIT registers */ 17 #define PIT_MODE 0x43 18 #define PIT_CH0 0x40 19 #define PIT_CH2 0x42 20 21 #define PIT_LATCH ((PIT_TICK_RATE + HZ/2) / HZ) 22 23 extern raw_spinlock_t i8253_lock; 24 extern bool i8253_clear_counter_on_shutdown; 25 extern struct clock_event_device i8253_clockevent; 26 extern void clockevent_i8253_init(bool oneshot); 27 28 extern void setup_pit_timer(void); 29 30 #endif /* __LINUX_I8253_H */ 31