xref: /openbmc/linux/arch/mips/fw/arc/promlib.c (revision 958ef1e3)
1 /*
2  * This file is subject to the terms and conditions of the GNU General Public
3  * License.  See the file "COPYING" in the main directory of this archive
4  * for more details.
5  *
6  * Copyright (C) 1996 David S. Miller (dm@sgi.com)
7  * Compatibility with board caches, Ulf Carlsson
8  */
9 #include <linux/kernel.h>
10 #include <asm/sgialib.h>
11 #include <asm/bcache.h>
12 #include <asm/setup.h>
13 
14 /*
15  * IP22 boardcache is not compatible with board caches.	 Thus we disable it
16  * during romvec action.  Since r4xx0.c is always compiled and linked with your
17  * kernel, this shouldn't cause any harm regardless what MIPS processor you
18  * have.
19  *
20  * The ARC write and read functions seem to interfere with the serial lines
21  * in some way. You should be careful with them.
22  */
23 
24 void prom_putchar(char c)
25 {
26 	ULONG cnt;
27 	CHAR it = c;
28 
29 	bc_disable();
30 	ArcWrite(1, &it, 1, &cnt);
31 	bc_enable();
32 }
33 
34 char prom_getchar(void)
35 {
36 	ULONG cnt;
37 	CHAR c;
38 
39 	bc_disable();
40 	ArcRead(0, &c, 1, &cnt);
41 	bc_enable();
42 
43 	return c;
44 }
45