1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _MC6821_H_
3#define _MC6821_H_
4
5/*
6 * This file describes the memery mapping of the MC6821 PIA.
7 * The unions describe overlayed registers. Which of them is used is
8 * determined by bit 2 of the corresponding control register.
9 * this files expects the PIA_REG_PADWIDTH to be defined the numeric
10 * value of the register spacing.
11 *
12 * Data came from MFC-31-Developer Kit (from Ralph Seidel,
13 * zodiac@darkness.gun.de) and Motorola Data Sheet (from
14 * Richard Hirst, srh@gpt.co.uk)
15 *
16 * 6.11.95 copyright Joerg Dorchain (dorchain@mpi-sb.mpg.de)
17 *
18 */
19
20#ifndef PIA_REG_PADWIDTH
21#define PIA_REG_PADWIDTH 255
22#endif
23
24struct pia {
25	union {
26		volatile u_char pra;
27		volatile u_char ddra;
28	} ua;
29	u_char pad1[PIA_REG_PADWIDTH];
30	volatile u_char cra;
31	u_char pad2[PIA_REG_PADWIDTH];
32	union {
33		volatile u_char prb;
34		volatile u_char ddrb;
35	} ub;
36	u_char pad3[PIA_REG_PADWIDTH];
37	volatile u_char crb;
38	u_char pad4[PIA_REG_PADWIDTH];
39};
40
41#define ppra ua.pra
42#define pddra ua.ddra
43#define pprb ub.prb
44#define pddrb ub.ddrb
45
46#define PIA_C1_ENABLE_IRQ (1<<0)
47#define PIA_C1_LOW_TO_HIGH (1<<1)
48#define PIA_DDR (1<<2)
49#define PIA_IRQ2 (1<<6)
50#define PIA_IRQ1 (1<<7)
51
52#endif
53