1/*
2 * ARAnyM console driver
3 *
4 * This file is subject to the terms and conditions of the GNU General Public
5 * License.  See the file COPYING in the main directory of this archive
6 * for more details.
7 */
8
9#include <linux/module.h>
10#include <linux/init.h>
11#include <linux/console.h>
12#include <linux/tty.h>
13#include <linux/tty_driver.h>
14#include <linux/tty_flip.h>
15#include <linux/slab.h>
16#include <linux/err.h>
17#include <linux/uaccess.h>
18#include <linux/io.h>
19
20#include <asm/natfeat.h>
21
22static int stderr_id;
23static struct tty_port nfcon_tty_port;
24static struct tty_driver *nfcon_tty_driver;
25
26static void nfputs(const u8 *str, size_t count)
27{
28	u8 buf[68];
29	unsigned long phys = virt_to_phys(buf);
30
31	buf[64] = 0;
32	while (count > 64) {
33		memcpy(buf, str, 64);
34		nf_call(stderr_id, phys);
35		str += 64;
36		count -= 64;
37	}
38	memcpy(buf, str, count);
39	buf[count] = 0;
40	nf_call(stderr_id, phys);
41}
42
43static void nfcon_write(struct console *con, const char *str,
44			unsigned int count)
45{
46	nfputs(str, count);
47}
48
49static struct tty_driver *nfcon_device(struct console *con, int *index)
50{
51	*index = 0;
52	return console_is_registered(con) ? nfcon_tty_driver : NULL;
53}
54
55static struct console nf_console = {
56	.name	= "nfcon",
57	.write	= nfcon_write,
58	.device	= nfcon_device,
59	.flags	= CON_PRINTBUFFER,
60	.index	= -1,
61};
62
63
64static int nfcon_tty_open(struct tty_struct *tty, struct file *filp)
65{
66	return 0;
67}
68
69static void nfcon_tty_close(struct tty_struct *tty, struct file *filp)
70{
71}
72
73static ssize_t nfcon_tty_write(struct tty_struct *tty, const u8 *buf,
74			       size_t count)
75{
76	nfputs(buf, count);
77	return count;
78}
79
80static int nfcon_tty_put_char(struct tty_struct *tty, u8 ch)
81{
82	u8 temp[2] = { ch, 0 };
83
84	nf_call(stderr_id, virt_to_phys(temp));
85	return 1;
86}
87
88static unsigned int nfcon_tty_write_room(struct tty_struct *tty)
89{
90	return 64;
91}
92
93static const struct tty_operations nfcon_tty_ops = {
94	.open		= nfcon_tty_open,
95	.close		= nfcon_tty_close,
96	.write		= nfcon_tty_write,
97	.put_char	= nfcon_tty_put_char,
98	.write_room	= nfcon_tty_write_room,
99};
100
101#ifndef MODULE
102
103static int __init nf_debug_setup(char *arg)
104{
105	if (strcmp(arg, "nfcon"))
106		return 0;
107
108	stderr_id = nf_get_id("NF_STDERR");
109	if (stderr_id) {
110		/*
111		 * The console will be enabled when debug=nfcon is specified
112		 * as a kernel parameter. Since this is a non-standard way
113		 * of enabling consoles, it must be explicitly enabled.
114		 */
115		nf_console.flags |= CON_ENABLED;
116		register_console(&nf_console);
117	}
118
119	return 0;
120}
121
122early_param("debug", nf_debug_setup);
123
124#endif /* !MODULE */
125
126static int __init nfcon_init(void)
127{
128	struct tty_driver *driver;
129	int res;
130
131	stderr_id = nf_get_id("NF_STDERR");
132	if (!stderr_id)
133		return -ENODEV;
134
135	driver = tty_alloc_driver(1, TTY_DRIVER_REAL_RAW);
136	if (IS_ERR(driver))
137		return PTR_ERR(driver);
138
139	tty_port_init(&nfcon_tty_port);
140
141	driver->driver_name = "nfcon";
142	driver->name = "nfcon";
143	driver->type = TTY_DRIVER_TYPE_SYSTEM;
144	driver->subtype = SYSTEM_TYPE_TTY;
145	driver->init_termios = tty_std_termios;
146
147	tty_set_operations(driver, &nfcon_tty_ops);
148	tty_port_link_device(&nfcon_tty_port, driver, 0);
149	res = tty_register_driver(driver);
150	if (res) {
151		pr_err("failed to register nfcon tty driver\n");
152		tty_driver_kref_put(driver);
153		tty_port_destroy(&nfcon_tty_port);
154		return res;
155	}
156
157	nfcon_tty_driver = driver;
158
159	if (!console_is_registered(&nf_console))
160		register_console(&nf_console);
161
162	return 0;
163}
164
165static void __exit nfcon_exit(void)
166{
167	unregister_console(&nf_console);
168	tty_unregister_driver(nfcon_tty_driver);
169	tty_driver_kref_put(nfcon_tty_driver);
170	tty_port_destroy(&nfcon_tty_port);
171}
172
173module_init(nfcon_init);
174module_exit(nfcon_exit);
175
176MODULE_LICENSE("GPL");
177