1 /*
2  * hvconsole.c
3  * Copyright (C) 2004 Hollis Blanchard, IBM Corporation
4  * Copyright (C) 2004 IBM Corporation
5  *
6  * Additional Author(s):
7  *  Ryan S. Arnold <rsa@us.ibm.com>
8  *
9  * LPAR console support.
10  *
11  * This program is free software; you can redistribute it and/or modify
12  * it under the terms of the GNU General Public License as published by
13  * the Free Software Foundation; either version 2 of the License, or
14  * (at your option) any later version.
15  *
16  * This program is distributed in the hope that it will be useful,
17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
19  * GNU General Public License for more details.
20  *
21  * You should have received a copy of the GNU General Public License
22  * along with this program; if not, write to the Free Software
23  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
24  */
25 
26 #include <linux/kernel.h>
27 #include <linux/export.h>
28 #include <linux/errno.h>
29 #include <asm/hvcall.h>
30 #include <asm/hvconsole.h>
31 #include <asm/plpar_wrappers.h>
32 
33 /**
34  * hvc_get_chars - retrieve characters from firmware for denoted vterm adapter
35  * @vtermno: The vtermno or unit_address of the adapter from which to fetch the
36  *	data.
37  * @buf: The character buffer into which to put the character data fetched from
38  *	firmware.
39  * @count: not used?
40  */
41 int hvc_get_chars(uint32_t vtermno, char *buf, int count)
42 {
43 	long ret;
44 	unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
45 	unsigned long *lbuf = (unsigned long *)buf;
46 
47 	ret = plpar_hcall(H_GET_TERM_CHAR, retbuf, vtermno);
48 	lbuf[0] = be64_to_cpu(retbuf[1]);
49 	lbuf[1] = be64_to_cpu(retbuf[2]);
50 
51 	if (ret == H_SUCCESS)
52 		return retbuf[0];
53 
54 	return 0;
55 }
56 
57 EXPORT_SYMBOL(hvc_get_chars);
58 
59 
60 /**
61  * hvc_put_chars: send characters to firmware for denoted vterm adapter
62  * @vtermno: The vtermno or unit_address of the adapter from which the data
63  *	originated.
64  * @buf: The character buffer that contains the character data to send to
65  *	firmware.
66  * @count: Send this number of characters.
67  */
68 int hvc_put_chars(uint32_t vtermno, const char *buf, int count)
69 {
70 	unsigned long *lbuf = (unsigned long *) buf;
71 	long ret;
72 
73 
74 	/* hcall will ret H_PARAMETER if 'count' exceeds firmware max.*/
75 	if (count > MAX_VIO_PUT_CHARS)
76 		count = MAX_VIO_PUT_CHARS;
77 
78 	ret = plpar_hcall_norets(H_PUT_TERM_CHAR, vtermno, count,
79 				 cpu_to_be64(lbuf[0]),
80 				 cpu_to_be64(lbuf[1]));
81 	if (ret == H_SUCCESS)
82 		return count;
83 	if (ret == H_BUSY)
84 		return -EAGAIN;
85 	return -EIO;
86 }
87 
88 EXPORT_SYMBOL(hvc_put_chars);
89