1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * udbg interface to hvc_console.c
4 *
5 * (C) Copyright David Gibson, IBM Corporation 2008.
6 */
7
8#include <linux/console.h>
9#include <linux/delay.h>
10#include <linux/err.h>
11#include <linux/init.h>
12#include <linux/moduleparam.h>
13#include <linux/types.h>
14#include <linux/irq.h>
15
16#include <asm/udbg.h>
17
18#include "hvc_console.h"
19
20static struct hvc_struct *hvc_udbg_dev;
21
22static ssize_t hvc_udbg_put(uint32_t vtermno, const u8 *buf, size_t count)
23{
24 size_t i;
25
26 for (i = 0; i < count && udbg_putc; i++)
27 udbg_putc(buf[i]);
28
29 return i;
30}
31
32static ssize_t hvc_udbg_get(uint32_t vtermno, u8 *buf, size_t count)
33{
34 size_t i;
35 int c;
36
37 if (!udbg_getc_poll)
38 return 0;
39
40 for (i = 0; i < count; i++) {
41 if ((c = udbg_getc_poll()) == -1)
42 break;
43 buf[i] = c;
44 }
45
46 return i;
47}
48
49static const struct hv_ops hvc_udbg_ops = {
50 .get_chars = hvc_udbg_get,
51 .put_chars = hvc_udbg_put,
52};
53
54static int __init hvc_udbg_init(void)
55{
56 struct hvc_struct *hp;
57
58 if (!udbg_putc)
59 return -ENODEV;
60
61 BUG_ON(hvc_udbg_dev);
62
63 hp = hvc_alloc(vtermno: 0, data: 0, ops: &hvc_udbg_ops, outbuf_size: 16);
64 if (IS_ERR(ptr: hp))
65 return PTR_ERR(ptr: hp);
66
67 hvc_udbg_dev = hp;
68
69 return 0;
70}
71device_initcall(hvc_udbg_init);
72
73static int __init hvc_udbg_console_init(void)
74{
75 if (!udbg_putc)
76 return -ENODEV;
77
78 hvc_instantiate(vtermno: 0, index: 0, ops: &hvc_udbg_ops);
79 add_preferred_console(name: "hvc", idx: 0, NULL);
80
81 return 0;
82}
83console_initcall(hvc_udbg_console_init);
84

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