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      1 /* $NetBSD: prom.c,v 1.16 2018/09/03 16:29:22 riastradh Exp $ */
      2 
      3 /*
      4  * Mach Operating System
      5  * Copyright (c) 1992 Carnegie Mellon University
      6  * All Rights Reserved.
      7  *
      8  * Permission to use, copy, modify and distribute this software and its
      9  * documentation is hereby granted, provided that both the copyright
     10  * notice and this permission notice appear in all copies of the
     11  * software, derivative works or modified versions, and any portions
     12  * thereof, and that both notices appear in supporting documentation.
     13  *
     14  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
     15  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
     16  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
     17  *
     18  * Carnegie Mellon requests users of this software to return to
     19  *
     20  *  Software Distribution Coordinator  or  Software.Distribution (at) CS.CMU.EDU
     21  *  School of Computer Science
     22  *  Carnegie Mellon University
     23  *  Pittsburgh PA 15213-3890
     24  *
     25  * any improvements or extensions that they make and grant Carnegie Mellon
     26  * the rights to redistribute these changes.
     27  */
     28 
     29 #include <lib/libkern/libkern.h>
     30 
     31 #include <sys/types.h>
     32 
     33 #include <machine/prom.h>
     34 #include <machine/rpb.h>
     35 
     36 #include "common.h"
     37 
     38 int console;
     39 
     40 #if !defined(NO_GETCHAR) || !defined(NO_PUTCHAR_HALT)
     41 static int test_getchar(int *);
     42 #endif
     43 static void putonechar(int c);
     44 
     45 void
     46 init_prom_calls(void)
     47 {
     48 	extern struct prom_vec prom_dispatch_v;
     49 	struct rpb *r;
     50 	struct crb *c;
     51 	char buf[4];
     52 
     53 	r = (struct rpb *)HWRPB_ADDR;
     54 	c = (struct crb *)((u_int8_t *)r + r->rpb_crb_off);
     55 
     56 	prom_dispatch_v.routine_arg = c->crb_v_dispatch;
     57 	prom_dispatch_v.routine = c->crb_v_dispatch->entry_va;
     58 
     59 	/* Look for console tty. */
     60 	prom_getenv(PROM_E_TTY_DEV, buf, sizeof(buf));
     61 	console = buf[0] - '0';
     62 }
     63 
     64 #if !defined(NO_GETCHAR) || !defined(NO_PUTCHAR_HALT)
     65 static int
     66 test_getchar(int *xc)
     67 {
     68 	prom_return_t ret;
     69 
     70 	ret.bits = prom_dispatch(PROM_R_GETC, console);
     71 	*xc = ret.u.retval;
     72 	return ret.u.status == 0 || ret.u.status == 1;
     73 }
     74 #endif
     75 
     76 #if !defined(NO_GETCHAR)
     77 int
     78 getchar(void)
     79 {
     80 	int c;
     81 
     82 	for (;;) {
     83 		if (test_getchar(&c)) {
     84 			if (c == 3)
     85 				halt();
     86 			return c;
     87 		}
     88 	}
     89 }
     90 #endif
     91 
     92 static void
     93 putonechar(int c)
     94 {
     95 	prom_return_t ret;
     96 	char cbuf = c;
     97 
     98 	do {
     99 		ret.bits = prom_dispatch(PROM_R_PUTS, console, &cbuf, 1);
    100 	} while ((ret.u.retval & 1) == 0);
    101 }
    102 
    103 void
    104 putchar(int c)
    105 {
    106 #if !defined(NO_PUTCHAR_HALT)
    107 	int typed_c;
    108 #endif
    109 
    110 	if (c == '\r' || c == '\n') {
    111 		putonechar('\r');
    112 		c = '\n';
    113 	}
    114 	putonechar(c);
    115 #if !defined(NO_PUTCHAR_HALT)
    116 	if (test_getchar(&typed_c))
    117 		if (typed_c == 3)
    118 			halt();
    119 #endif
    120 }
    121 
    122 int
    123 prom_getenv(int id, char *buf, int len)
    124 {
    125 	/*
    126 	 * On at least some systems, the GETENV call requires a
    127 	 * 8-byte-aligned buffer, or it bails out with a "kernel stack
    128 	 * not valid halt". Provide a local, aligned buffer here and
    129 	 * then copy to the caller's buffer.
    130 	 */
    131 	static char abuf[128] __attribute__((aligned (8)));
    132 	prom_return_t ret;
    133 
    134 	ret.bits = prom_dispatch(PROM_R_GETENV, id, abuf, 128);
    135 	if (ret.u.status & 0x4)
    136 		ret.u.retval = 0;
    137 	len = uimin(len - 1, ret.u.retval);
    138 	memcpy(buf, abuf, len);
    139 	buf[len] = '\0';
    140 
    141 	return (len);
    142 }
    143