Root/drivers/tty/hvc/hvc_rtas.c

1/*
2 * IBM RTAS driver interface to hvc_console.c
3 *
4 * (C) Copyright IBM Corporation 2001-2005
5 * (C) Copyright Red Hat, Inc. 2005
6 *
7 * Author(s): Maximino Augilar <IBM STI Design Center>
8 * : Ryan S. Arnold <rsa@us.ibm.com>
9 * : Utz Bacher <utz.bacher@de.ibm.com>
10 * : David Woodhouse <dwmw2@infradead.org>
11 *
12 * inspired by drivers/char/hvc_console.c
13 * written by Anton Blanchard and Paul Mackerras
14 *
15 * This program is free software; you can redistribute it and/or modify
16 * it under the terms of the GNU General Public License as published by
17 * the Free Software Foundation; either version 2 of the License, or
18 * (at your option) any later version.
19 *
20 * This program is distributed in the hope that it will be useful,
21 * but WITHOUT ANY WARRANTY; without even the implied warranty of
22 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
23 * GNU General Public License for more details.
24 *
25 * You should have received a copy of the GNU General Public License
26 * along with this program; if not, write to the Free Software
27 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
28 */
29
30#include <linux/console.h>
31#include <linux/delay.h>
32#include <linux/err.h>
33#include <linux/init.h>
34#include <linux/moduleparam.h>
35#include <linux/types.h>
36
37#include <asm/irq.h>
38#include <asm/rtas.h>
39#include "hvc_console.h"
40
41#define hvc_rtas_cookie 0x67781e15
42struct hvc_struct *hvc_rtas_dev;
43
44static int rtascons_put_char_token = RTAS_UNKNOWN_SERVICE;
45static int rtascons_get_char_token = RTAS_UNKNOWN_SERVICE;
46
47static inline int hvc_rtas_write_console(uint32_t vtermno, const char *buf,
48        int count)
49{
50    int i;
51
52    for (i = 0; i < count; i++) {
53        if (rtas_call(rtascons_put_char_token, 1, 1, NULL, buf[i]))
54            break;
55    }
56
57    return i;
58}
59
60static int hvc_rtas_read_console(uint32_t vtermno, char *buf, int count)
61{
62    int i, c;
63
64    for (i = 0; i < count; i++) {
65        if (rtas_call(rtascons_get_char_token, 0, 2, &c))
66            break;
67
68        buf[i] = c;
69    }
70
71    return i;
72}
73
74static const struct hv_ops hvc_rtas_get_put_ops = {
75    .get_chars = hvc_rtas_read_console,
76    .put_chars = hvc_rtas_write_console,
77};
78
79static int __init hvc_rtas_init(void)
80{
81    struct hvc_struct *hp;
82
83    if (rtascons_put_char_token == RTAS_UNKNOWN_SERVICE)
84        rtascons_put_char_token = rtas_token("put-term-char");
85    if (rtascons_put_char_token == RTAS_UNKNOWN_SERVICE)
86        return -EIO;
87
88    if (rtascons_get_char_token == RTAS_UNKNOWN_SERVICE)
89        rtascons_get_char_token = rtas_token("get-term-char");
90    if (rtascons_get_char_token == RTAS_UNKNOWN_SERVICE)
91        return -EIO;
92
93    BUG_ON(hvc_rtas_dev);
94
95    /* Allocate an hvc_struct for the console device we instantiated
96     * earlier. Save off hp so that we can return it on exit */
97    hp = hvc_alloc(hvc_rtas_cookie, 0, &hvc_rtas_get_put_ops, 16);
98    if (IS_ERR(hp))
99        return PTR_ERR(hp);
100
101    hvc_rtas_dev = hp;
102
103    return 0;
104}
105module_init(hvc_rtas_init);
106
107/* This will tear down the tty portion of the driver */
108static void __exit hvc_rtas_exit(void)
109{
110    /* Really the fun isn't over until the worker thread breaks down and
111     * the tty cleans up */
112    if (hvc_rtas_dev)
113        hvc_remove(hvc_rtas_dev);
114}
115module_exit(hvc_rtas_exit);
116
117/* This will happen prior to module init. There is no tty at this time? */
118static int __init hvc_rtas_console_init(void)
119{
120    rtascons_put_char_token = rtas_token("put-term-char");
121    if (rtascons_put_char_token == RTAS_UNKNOWN_SERVICE)
122        return -EIO;
123
124    rtascons_get_char_token = rtas_token("get-term-char");
125    if (rtascons_get_char_token == RTAS_UNKNOWN_SERVICE)
126        return -EIO;
127
128    hvc_instantiate(hvc_rtas_cookie, 0, &hvc_rtas_get_put_ops);
129    add_preferred_console("hvc", 0, NULL);
130
131    return 0;
132}
133console_initcall(hvc_rtas_console_init);
134

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