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 | |
24 | struct 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 | |