1 /* console.c: Routines that deal with sending and receiving IO 2 * to/from the current console device using the PROM. 3 * 4 * Copyright (C) 1995 David S. Miller (davem@davemloft.net) 5 * Copyright (C) 1996,1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz) 6 */ 7 8 #include <linux/types.h> 9 #include <linux/kernel.h> 10 #include <linux/sched.h> 11 #include <asm/openprom.h> 12 #include <asm/oplib.h> 13 #include <asm/system.h> 14 #include <linux/string.h> 15 16 extern int prom_stdin, prom_stdout; 17 18 /* Non blocking get character from console input device, returns -1 19 * if no input was taken. This can be used for polling. 20 */ 21 static int prom_nbgetchar(void) 22 { 23 unsigned long args[7]; 24 char inc; 25 26 args[0] = (unsigned long) "read"; 27 args[1] = 3; 28 args[2] = 1; 29 args[3] = (unsigned int) prom_stdin; 30 args[4] = (unsigned long) &inc; 31 args[5] = 1; 32 args[6] = (unsigned long) -1; 33 34 p1275_cmd_direct(args); 35 36 if (args[6] == 1) 37 return inc; 38 return -1; 39 } 40 41 /* Non blocking put character to console device, returns -1 if 42 * unsuccessful. 43 */ 44 static int prom_nbputchar(char c) 45 { 46 unsigned long args[7]; 47 char outc; 48 49 outc = c; 50 51 args[0] = (unsigned long) "write"; 52 args[1] = 3; 53 args[2] = 1; 54 args[3] = (unsigned int) prom_stdout; 55 args[4] = (unsigned long) &outc; 56 args[5] = 1; 57 args[6] = (unsigned long) -1; 58 59 p1275_cmd_direct(args); 60 61 if (args[6] == 1) 62 return 0; 63 else 64 return -1; 65 } 66 67 /* Blocking version of get character routine above. */ 68 char 69 prom_getchar(void) 70 { 71 int character; 72 while((character = prom_nbgetchar()) == -1) ; 73 return (char) character; 74 } 75 76 /* Blocking version of put character routine above. */ 77 void 78 prom_putchar(char c) 79 { 80 prom_nbputchar(c); 81 } 82