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