src/include/pc80/i8254.h

/* SPDX-License-Identifier: GPL-2.0-only */

#ifndef PC80_I8254_H
#define PC80_I8254_H

/* Ports for the 8254 timer chip */
#define TIMER0_PORT	0x40
#define TIMER1_PORT	0x41
#define TIMER2_PORT     0x42
#define TIMER_MODE_PORT 0x43

/* Meaning of the mode bits */
#define TIMER0_SEL      0x00
#define TIMER1_SEL      0x40
#define TIMER2_SEL      0x80
#define READBACK_SEL    0xC0

#define LATCH_COUNT     0x00
#define LOBYTE_ACCESS   0x10
#define HIBYTE_ACCESS   0x20
#define WORD_ACCESS     0x30

#define MODE0           0x00
#define MODE1           0x02
#define MODE2           0x04
#define MODE3           0x06
#define MODE4           0x08
#define MODE5           0x0A

#define BINARY_COUNT    0x00
#define BCD_COUNT       0x01

/* Timers tick over at this rate */
#define TICKS_PER_MS    1193

/* Parallel Peripheral Controller Port B */
#define PPC_PORTB       0x61

/* Meaning of the port bits */
#define PPCB_T2OUT      0x20    /* Bit 5 */
#define PPCB_SPKR       0x02    /* Bit 1 */
#define PPCB_T2GATE     0x01    /* Bit 0 */

void setup_i8254(void);
unsigned long calibrate_tsc_with_pit(void);
void beep(unsigned int frequency_hz, unsigned int duration_msec);

#endif /* PC80_I8254_H */