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
29 static struct hvc_struct *hvc_rtas_dev;
30
31 static int rtascons_put_char_token = RTAS_UNKNOWN_SERVICE;
32 static int rtascons_get_char_token = RTAS_UNKNOWN_SERVICE;
33
hvc_rtas_write_console(uint32_t vtermno,const char * buf,int count)34 static 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
hvc_rtas_read_console(uint32_t vtermno,char * buf,int count)47 static 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
61 static 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
hvc_rtas_init(void)66 static 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, 0, &hvc_rtas_get_put_ops, 16);
85 if (IS_ERR(hp))
86 return PTR_ERR(hp);
87
88 hvc_rtas_dev = hp;
89
90 return 0;
91 }
92 device_initcall(hvc_rtas_init);
93
94 /* This will happen prior to module init. There is no tty at this time? */
hvc_rtas_console_init(void)95 static 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, 0, &hvc_rtas_get_put_ops);
106 add_preferred_console("hvc", 0, NULL);
107
108 return 0;
109 }
110 console_initcall(hvc_rtas_console_init);
111