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 | |
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 | |
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 | |
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, 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 | } |
92 | device_initcall(hvc_rtas_init); |
93 | |
94 | /* This will happen prior to module init. There is no tty at this time? */ |
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, index: 0, ops: &hvc_rtas_get_put_ops); |
106 | add_preferred_console(name: "hvc" , idx: 0, NULL); |
107 | |
108 | return 0; |
109 | } |
110 | console_initcall(hvc_rtas_console_init); |
111 | |