1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * IBM RTAS driver interface to hvc_console.c
4 *
5 * (C) Copyright IBM Corporation 2001-2005
6 * (C) Copyright Red Hat, Inc. 2005
7 *
8 * Author(s): Maximino Augilar <IBM STI Design Center>
9 * : Ryan S. Arnold <rsa@us.ibm.com>
10 * : Utz Bacher <utz.bacher@de.ibm.com>
11 * : David Woodhouse <dwmw2@infradead.org>
12 *
13 * inspired by drivers/char/hvc_console.c
14 * written by Anton Blanchard and Paul Mackerras
15 */
16
17#include <linux/console.h>
18#include <linux/delay.h>
19#include <linux/err.h>
20#include <linux/init.h>
21#include <linux/moduleparam.h>
22#include <linux/types.h>
23
24#include <asm/irq.h>
25#include <asm/rtas.h>
26#include "hvc_console.h"
27
28#define hvc_rtas_cookie 0x67781e15
29static struct hvc_struct *hvc_rtas_dev;
30
31static int rtascons_put_char_token = RTAS_UNKNOWN_SERVICE;
32static int rtascons_get_char_token = RTAS_UNKNOWN_SERVICE;
33
34static inline int hvc_rtas_write_console(uint32_t vtermno, const char *buf,
35 int count)
36{
37 int i;
38
39 for (i = 0; i < count; i++) {
40 if (rtas_call(rtascons_put_char_token, 1, 1, NULL, buf[i]))
41 break;
42 }
43
44 return i;
45}
46
47static int hvc_rtas_read_console(uint32_t vtermno, char *buf, int count)
48{
49 int i, c;
50
51 for (i = 0; i < count; i++) {
52 if (rtas_call(rtascons_get_char_token, 0, 2, &c))
53 break;
54
55 buf[i] = c;
56 }
57
58 return i;
59}
60
61static const struct hv_ops hvc_rtas_get_put_ops = {
62 .get_chars = hvc_rtas_read_console,
63 .put_chars = hvc_rtas_write_console,
64};
65
66static int __init hvc_rtas_init(void)
67{
68 struct hvc_struct *hp;
69
70 if (rtascons_put_char_token == RTAS_UNKNOWN_SERVICE)
71 rtascons_put_char_token = rtas_token("put-term-char");
72 if (rtascons_put_char_token == RTAS_UNKNOWN_SERVICE)
73 return -EIO;
74
75 if (rtascons_get_char_token == RTAS_UNKNOWN_SERVICE)
76 rtascons_get_char_token = rtas_token("get-term-char");
77 if (rtascons_get_char_token == RTAS_UNKNOWN_SERVICE)
78 return -EIO;
79
80 BUG_ON(hvc_rtas_dev);
81
82 /* Allocate an hvc_struct for the console device we instantiated
83 * earlier. Save off hp so that we can return it on exit */
84 hp = hvc_alloc(hvc_rtas_cookie, data: 0, ops: &hvc_rtas_get_put_ops, outbuf_size: 16);
85 if (IS_ERR(ptr: hp))
86 return PTR_ERR(ptr: hp);
87
88 hvc_rtas_dev = hp;
89
90 return 0;
91}
92device_initcall(hvc_rtas_init);
93
94/* This will happen prior to module init. There is no tty at this time? */
95static int __init hvc_rtas_console_init(void)
96{
97 rtascons_put_char_token = rtas_token("put-term-char");
98 if (rtascons_put_char_token == RTAS_UNKNOWN_SERVICE)
99 return -EIO;
100
101 rtascons_get_char_token = rtas_token("get-term-char");
102 if (rtascons_get_char_token == RTAS_UNKNOWN_SERVICE)
103 return -EIO;
104
105 hvc_instantiate(hvc_rtas_cookie, index: 0, ops: &hvc_rtas_get_put_ops);
106 add_preferred_console(name: "hvc", idx: 0, NULL);
107
108 return 0;
109}
110console_initcall(hvc_rtas_console_init);
111

source code of linux/drivers/tty/hvc/hvc_rtas.c