/* $NetBSD: prom.c,v 1.16 2018/09/03 16:29:22 riastradh Exp $ */

/*  
 * Mach Operating System
 * Copyright (c) 1992 Carnegie Mellon University
 * All Rights Reserved.
 * 
 * Permission to use, copy, modify and distribute this software and its
 * documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 * 
 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 * 
 * Carnegie Mellon requests users of this software to return to
 * 
 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 * 
 * any improvements or extensions that they make and grant Carnegie Mellon
 * the rights to redistribute these changes.
 */

#include <lib/libkern/libkern.h>

#include <sys/types.h>

#include <machine/prom.h>
#include <machine/rpb.h>

#include "common.h"

int console;

#if !defined(NO_GETCHAR) || !defined(NO_PUTCHAR_HALT)
static int test_getchar(int *);
#endif
static void putonechar(int c);

void
init_prom_calls(void)
{
        extern struct prom_vec prom_dispatch_v;
        struct rpb *r;
        struct crb *c;
        char buf[4];

        r = (struct rpb *)HWRPB_ADDR;
        c = (struct crb *)((u_int8_t *)r + r->rpb_crb_off);

        prom_dispatch_v.routine_arg = c->crb_v_dispatch;
        prom_dispatch_v.routine = c->crb_v_dispatch->entry_va;

        /* Look for console tty. */
        prom_getenv(PROM_E_TTY_DEV, buf, sizeof(buf));
        console = buf[0] - '0';
}

#if !defined(NO_GETCHAR) || !defined(NO_PUTCHAR_HALT)
static int
test_getchar(int *xc)
{
        prom_return_t ret;

        ret.bits = prom_dispatch(PROM_R_GETC, console);
        *xc = ret.u.retval;
        return ret.u.status == 0 || ret.u.status == 1;
}
#endif

#if !defined(NO_GETCHAR)
int
getchar(void)
{
        int c;

        for (;;) {
                if (test_getchar(&c)) {
                        if (c == 3)
                                halt();
                        return c;
                }
        }
}
#endif

static void
putonechar(int c)
{
        prom_return_t ret;
        char cbuf = c;

        do {
                ret.bits = prom_dispatch(PROM_R_PUTS, console, &cbuf, 1);
        } while ((ret.u.retval & 1) == 0);
}

void
putchar(int c)
{
#if !defined(NO_PUTCHAR_HALT)
        int typed_c;
#endif

        if (c == '\r' || c == '\n') {
                putonechar('\r');
                c = '\n';
        }
        putonechar(c);
#if !defined(NO_PUTCHAR_HALT)
        if (test_getchar(&typed_c))
                if (typed_c == 3)
                        halt();
#endif
}

int
prom_getenv(int id, char *buf, int len)
{
        /* 
         * On at least some systems, the GETENV call requires a
         * 8-byte-aligned buffer, or it bails out with a "kernel stack
         * not valid halt". Provide a local, aligned buffer here and
         * then copy to the caller's buffer.
         */
        static char abuf[128] __attribute__((aligned (8)));
        prom_return_t ret;

        ret.bits = prom_dispatch(PROM_R_GETENV, id, abuf, 128);
        if (ret.u.status & 0x4)
                ret.u.retval = 0;
        len = uimin(len - 1, ret.u.retval);
        memcpy(buf, abuf, len);
        buf[len] = '\0';

        return (len);
}