xref: /openbmc/linux/arch/um/drivers/stdio_console.c (revision 0c6dfa75)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2000, 2001 Jeff Dike (jdike@karaya.com)
4  */
5 
6 #include <linux/posix_types.h>
7 #include <linux/tty.h>
8 #include <linux/tty_flip.h>
9 #include <linux/types.h>
10 #include <linux/major.h>
11 #include <linux/kdev_t.h>
12 #include <linux/console.h>
13 #include <linux/string.h>
14 #include <linux/sched.h>
15 #include <linux/list.h>
16 #include <linux/init.h>
17 #include <linux/interrupt.h>
18 #include <linux/slab.h>
19 #include <linux/hardirq.h>
20 #include <asm/current.h>
21 #include <asm/irq.h>
22 #include "stdio_console.h"
23 #include "chan.h"
24 #include <irq_user.h>
25 #include "mconsole_kern.h"
26 #include <init.h>
27 
28 #define MAX_TTYS (16)
29 
30 static void stdio_announce(char *dev_name, int dev)
31 {
32 	printk(KERN_INFO "Virtual console %d assigned device '%s'\n", dev,
33 	       dev_name);
34 }
35 
36 /* Almost const, except that xterm_title may be changed in an initcall */
37 static struct chan_opts opts = {
38 	.announce 	= stdio_announce,
39 	.xterm_title	= "Virtual Console #%d",
40 	.raw		= 1,
41 };
42 
43 static int con_config(char *str, char **error_out);
44 static int con_get_config(char *dev, char *str, int size, char **error_out);
45 static int con_remove(int n, char **con_remove);
46 
47 
48 /* Const, except for .mc.list */
49 static struct line_driver driver = {
50 	.name 			= "UML console",
51 	.device_name 		= "tty",
52 	.major 			= TTY_MAJOR,
53 	.minor_start 		= 0,
54 	.type 		 	= TTY_DRIVER_TYPE_CONSOLE,
55 	.subtype 	 	= SYSTEM_TYPE_CONSOLE,
56 	.read_irq_name 		= "console",
57 	.write_irq_name 	= "console-write",
58 	.mc  = {
59 		.list		= LIST_HEAD_INIT(driver.mc.list),
60 		.name  		= "con",
61 		.config 	= con_config,
62 		.get_config 	= con_get_config,
63 		.id		= line_id,
64 		.remove 	= con_remove,
65 	},
66 };
67 
68 /* The array is initialized by line_init, at initcall time.  The
69  * elements are locked individually as needed.
70  */
71 static char *vt_conf[MAX_TTYS];
72 static char *def_conf;
73 static struct line vts[MAX_TTYS];
74 
75 static int con_config(char *str, char **error_out)
76 {
77 	return line_config(vts, ARRAY_SIZE(vts), str, &opts, error_out);
78 }
79 
80 static int con_get_config(char *dev, char *str, int size, char **error_out)
81 {
82 	return line_get_config(dev, vts, ARRAY_SIZE(vts), str, size, error_out);
83 }
84 
85 static int con_remove(int n, char **error_out)
86 {
87 	return line_remove(vts, ARRAY_SIZE(vts), n, error_out);
88 }
89 
90 /* Set in an initcall, checked in an exitcall */
91 static int con_init_done;
92 
93 static int con_install(struct tty_driver *driver, struct tty_struct *tty)
94 {
95 	return line_install(driver, tty, &vts[tty->index]);
96 }
97 
98 static const struct tty_operations console_ops = {
99 	.open 	 		= line_open,
100 	.install		= con_install,
101 	.close 	 		= line_close,
102 	.write 	 		= line_write,
103 	.write_room		= line_write_room,
104 	.chars_in_buffer 	= line_chars_in_buffer,
105 	.flush_buffer 		= line_flush_buffer,
106 	.flush_chars 		= line_flush_chars,
107 	.throttle 		= line_throttle,
108 	.unthrottle 		= line_unthrottle,
109 	.hangup			= line_hangup,
110 };
111 
112 static void uml_console_write(struct console *console, const char *string,
113 			      unsigned len)
114 {
115 	struct line *line = &vts[console->index];
116 	unsigned long flags;
117 
118 	spin_lock_irqsave(&line->lock, flags);
119 	console_write_chan(line->chan_out, string, len);
120 	spin_unlock_irqrestore(&line->lock, flags);
121 }
122 
123 static struct tty_driver *uml_console_device(struct console *c, int *index)
124 {
125 	*index = c->index;
126 	return driver.driver;
127 }
128 
129 static int uml_console_setup(struct console *co, char *options)
130 {
131 	struct line *line = &vts[co->index];
132 
133 	return console_open_chan(line, co);
134 }
135 
136 /* No locking for register_console call - relies on single-threaded initcalls */
137 static struct console stdiocons = {
138 	.name		= "tty",
139 	.write		= uml_console_write,
140 	.device		= uml_console_device,
141 	.setup		= uml_console_setup,
142 	.flags		= CON_PRINTBUFFER|CON_ANYTIME,
143 	.index		= -1,
144 };
145 
146 static int stdio_init(void)
147 {
148 	char *new_title;
149 	int err;
150 	int i;
151 
152 	err = register_lines(&driver, &console_ops, vts,
153 					ARRAY_SIZE(vts));
154 	if (err)
155 		return err;
156 
157 	printk(KERN_INFO "Initialized stdio console driver\n");
158 
159 	new_title = add_xterm_umid(opts.xterm_title);
160 	if(new_title != NULL)
161 		opts.xterm_title = new_title;
162 
163 	for (i = 0; i < MAX_TTYS; i++) {
164 		char *error;
165 		char *s = vt_conf[i];
166 		if (!s)
167 			s = def_conf;
168 		if (!s)
169 			s = i ? CONFIG_CON_CHAN : CONFIG_CON_ZERO_CHAN;
170 		if (setup_one_line(vts, i, s, &opts, &error))
171 			printk(KERN_ERR "setup_one_line failed for "
172 			       "device %d : %s\n", i, error);
173 	}
174 
175 	con_init_done = 1;
176 	register_console(&stdiocons);
177 	return 0;
178 }
179 late_initcall(stdio_init);
180 
181 static void console_exit(void)
182 {
183 	if (!con_init_done)
184 		return;
185 	close_lines(vts, ARRAY_SIZE(vts));
186 }
187 __uml_exitcall(console_exit);
188 
189 static int console_chan_setup(char *str)
190 {
191 	if (!strncmp(str, "sole=", 5))	/* console= option specifies tty */
192 		return 0;
193 
194 	line_setup(vt_conf, MAX_TTYS, &def_conf, str, "console");
195 	return 1;
196 }
197 __setup("con", console_chan_setup);
198 __channel_help(console_chan_setup, "con");
199