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 ssize_t hvc_rtas_write_console(uint32_t vtermno, const u8 *buf, |
35 | size_t count) |
36 | { |
37 | size_t 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 ssize_t hvc_rtas_read_console(uint32_t vtermno, u8 *buf, size_t count) |
48 | { |
49 | size_t i; |
50 | int c; |
51 | |
52 | for (i = 0; i < count; i++) { |
53 | if (rtas_call(rtascons_get_char_token, 0, 2, &c)) |
54 | break; |
55 | |
56 | buf[i] = c; |
57 | } |
58 | |
59 | return i; |
60 | } |
61 | |
62 | static const struct hv_ops hvc_rtas_get_put_ops = { |
63 | .get_chars = hvc_rtas_read_console, |
64 | .put_chars = hvc_rtas_write_console, |
65 | }; |
66 | |
67 | static int __init hvc_rtas_init(void) |
68 | { |
69 | struct hvc_struct *hp; |
70 | |
71 | if (rtascons_put_char_token == RTAS_UNKNOWN_SERVICE) |
72 | rtascons_put_char_token = rtas_token("put-term-char" ); |
73 | if (rtascons_put_char_token == RTAS_UNKNOWN_SERVICE) |
74 | return -EIO; |
75 | |
76 | if (rtascons_get_char_token == RTAS_UNKNOWN_SERVICE) |
77 | rtascons_get_char_token = rtas_token("get-term-char" ); |
78 | if (rtascons_get_char_token == RTAS_UNKNOWN_SERVICE) |
79 | return -EIO; |
80 | |
81 | BUG_ON(hvc_rtas_dev); |
82 | |
83 | /* Allocate an hvc_struct for the console device we instantiated |
84 | * earlier. Save off hp so that we can return it on exit */ |
85 | hp = hvc_alloc(hvc_rtas_cookie, data: 0, ops: &hvc_rtas_get_put_ops, outbuf_size: 16); |
86 | if (IS_ERR(ptr: hp)) |
87 | return PTR_ERR(ptr: hp); |
88 | |
89 | hvc_rtas_dev = hp; |
90 | |
91 | return 0; |
92 | } |
93 | device_initcall(hvc_rtas_init); |
94 | |
95 | /* This will happen prior to module init. There is no tty at this time? */ |
96 | static int __init hvc_rtas_console_init(void) |
97 | { |
98 | rtascons_put_char_token = rtas_token("put-term-char" ); |
99 | if (rtascons_put_char_token == RTAS_UNKNOWN_SERVICE) |
100 | return -EIO; |
101 | |
102 | rtascons_get_char_token = rtas_token("get-term-char" ); |
103 | if (rtascons_get_char_token == RTAS_UNKNOWN_SERVICE) |
104 | return -EIO; |
105 | |
106 | hvc_instantiate(hvc_rtas_cookie, index: 0, ops: &hvc_rtas_get_put_ops); |
107 | add_preferred_console(name: "hvc" , idx: 0, NULL); |
108 | |
109 | return 0; |
110 | } |
111 | console_initcall(hvc_rtas_console_init); |
112 | |