xref: /linux/arch/xtensa/platforms/iss/console.c (revision 7056741fd9fc14a65608549a4657cf5178f05f63)
1 /*
2  * arch/xtensa/platforms/iss/console.c
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  * Copyright (C) 2001-2005 Tensilica Inc.
9  *   Authors	Christian Zankel, Joe Taylor
10  */
11 
12 #include <linux/module.h>
13 #include <linux/kernel.h>
14 #include <linux/sched.h>
15 #include <linux/console.h>
16 #include <linux/init.h>
17 #include <linux/mm.h>
18 #include <linux/major.h>
19 #include <linux/param.h>
20 #include <linux/seq_file.h>
21 #include <linux/serial.h>
22 
23 #include <asm/uaccess.h>
24 #include <asm/irq.h>
25 
26 #include <platform/simcall.h>
27 
28 #include <linux/tty.h>
29 #include <linux/tty_flip.h>
30 
31 #ifdef SERIAL_INLINE
32 #define _INLINE_ inline
33 #endif
34 
35 #define SERIAL_MAX_NUM_LINES 1
36 #define SERIAL_TIMER_VALUE (HZ / 10)
37 
38 static struct tty_driver *serial_driver;
39 static struct tty_port serial_port;
40 static struct timer_list serial_timer;
41 
42 static DEFINE_SPINLOCK(timer_lock);
43 
44 static char *serial_version = "0.1";
45 static char *serial_name = "ISS serial driver";
46 
47 /*
48  * This routine is called whenever a serial port is opened.  It
49  * enables interrupts for a serial port, linking in its async structure into
50  * the IRQ chain.   It also performs the serial-specific
51  * initialization for the tty structure.
52  */
53 
54 static void rs_poll(unsigned long);
55 
56 static int rs_open(struct tty_struct *tty, struct file * filp)
57 {
58 	tty->port = &serial_port;
59 	spin_lock(&timer_lock);
60 	if (tty->count == 1) {
61 		setup_timer(&serial_timer, rs_poll, (unsigned long)tty);
62 		mod_timer(&serial_timer, jiffies + SERIAL_TIMER_VALUE);
63 	}
64 	spin_unlock(&timer_lock);
65 
66 	return 0;
67 }
68 
69 
70 /*
71  * ------------------------------------------------------------
72  * iss_serial_close()
73  *
74  * This routine is called when the serial port gets closed.  First, we
75  * wait for the last remaining data to be sent.  Then, we unlink its
76  * async structure from the interrupt chain if necessary, and we free
77  * that IRQ if nothing is left in the chain.
78  * ------------------------------------------------------------
79  */
80 static void rs_close(struct tty_struct *tty, struct file * filp)
81 {
82 	spin_lock_bh(&timer_lock);
83 	if (tty->count == 1)
84 		del_timer_sync(&serial_timer);
85 	spin_unlock_bh(&timer_lock);
86 }
87 
88 
89 static int rs_write(struct tty_struct * tty,
90 		    const unsigned char *buf, int count)
91 {
92 	/* see drivers/char/serialX.c to reference original version */
93 
94 	__simc (SYS_write, 1, (unsigned long)buf, count, 0, 0);
95 	return count;
96 }
97 
98 static void rs_poll(unsigned long priv)
99 {
100 	struct tty_struct* tty = (struct tty_struct*) priv;
101 
102 	struct timeval tv = { .tv_sec = 0, .tv_usec = 0 };
103 	int i = 0;
104 	unsigned char c;
105 
106 	spin_lock(&timer_lock);
107 
108 	while (__simc(SYS_select_one, 0, XTISS_SELECT_ONE_READ, (int)&tv,0,0)){
109 		__simc (SYS_read, 0, (unsigned long)&c, 1, 0, 0);
110 		tty_insert_flip_char(tty, c, TTY_NORMAL);
111 		i++;
112 	}
113 
114 	if (i)
115 		tty_flip_buffer_push(tty);
116 
117 
118 	mod_timer(&serial_timer, jiffies + SERIAL_TIMER_VALUE);
119 	spin_unlock(&timer_lock);
120 }
121 
122 
123 static int rs_put_char(struct tty_struct *tty, unsigned char ch)
124 {
125 	char buf[2];
126 
127 	buf[0] = ch;
128 	buf[1] = '\0';		/* Is this NULL necessary? */
129 	__simc (SYS_write, 1, (unsigned long) buf, 1, 0, 0);
130 	return 1;
131 }
132 
133 static void rs_flush_chars(struct tty_struct *tty)
134 {
135 }
136 
137 static int rs_write_room(struct tty_struct *tty)
138 {
139 	/* Let's say iss can always accept 2K characters.. */
140 	return 2 * 1024;
141 }
142 
143 static int rs_chars_in_buffer(struct tty_struct *tty)
144 {
145 	/* the iss doesn't buffer characters */
146 	return 0;
147 }
148 
149 static void rs_hangup(struct tty_struct *tty)
150 {
151 	/* Stub, once again.. */
152 }
153 
154 static void rs_wait_until_sent(struct tty_struct *tty, int timeout)
155 {
156 	/* Stub, once again.. */
157 }
158 
159 static int rs_proc_show(struct seq_file *m, void *v)
160 {
161 	seq_printf(m, "serinfo:1.0 driver:%s\n", serial_version);
162 	return 0;
163 }
164 
165 static int rs_proc_open(struct inode *inode, struct file *file)
166 {
167 	return single_open(file, rs_proc_show, NULL);
168 }
169 
170 static const struct file_operations rs_proc_fops = {
171 	.owner		= THIS_MODULE,
172 	.open		= rs_proc_open,
173 	.read		= seq_read,
174 	.llseek		= seq_lseek,
175 	.release	= single_release,
176 };
177 
178 static const struct tty_operations serial_ops = {
179 	.open = rs_open,
180 	.close = rs_close,
181 	.write = rs_write,
182 	.put_char = rs_put_char,
183 	.flush_chars = rs_flush_chars,
184 	.write_room = rs_write_room,
185 	.chars_in_buffer = rs_chars_in_buffer,
186 	.hangup = rs_hangup,
187 	.wait_until_sent = rs_wait_until_sent,
188 	.proc_fops = &rs_proc_fops,
189 };
190 
191 int __init rs_init(void)
192 {
193 	tty_port_init(&serial_port);
194 
195 	serial_driver = alloc_tty_driver(SERIAL_MAX_NUM_LINES);
196 
197 	printk ("%s %s\n", serial_name, serial_version);
198 
199 	/* Initialize the tty_driver structure */
200 
201 	serial_driver->driver_name = "iss_serial";
202 	serial_driver->name = "ttyS";
203 	serial_driver->major = TTY_MAJOR;
204 	serial_driver->minor_start = 64;
205 	serial_driver->type = TTY_DRIVER_TYPE_SERIAL;
206 	serial_driver->subtype = SERIAL_TYPE_NORMAL;
207 	serial_driver->init_termios = tty_std_termios;
208 	serial_driver->init_termios.c_cflag =
209 		B9600 | CS8 | CREAD | HUPCL | CLOCAL;
210 	serial_driver->flags = TTY_DRIVER_REAL_RAW;
211 
212 	tty_set_operations(serial_driver, &serial_ops);
213 	tty_port_link_device(&serial_port, serial_driver, 0);
214 
215 	if (tty_register_driver(serial_driver))
216 		panic("Couldn't register serial driver\n");
217 	return 0;
218 }
219 
220 
221 static __exit void rs_exit(void)
222 {
223 	int error;
224 
225 	if ((error = tty_unregister_driver(serial_driver)))
226 		printk("ISS_SERIAL: failed to unregister serial driver (%d)\n",
227 		       error);
228 	put_tty_driver(serial_driver);
229 }
230 
231 
232 /* We use `late_initcall' instead of just `__initcall' as a workaround for
233  * the fact that (1) simcons_tty_init can't be called before tty_init,
234  * (2) tty_init is called via `module_init', (3) if statically linked,
235  * module_init == device_init, and (4) there's no ordering of init lists.
236  * We can do this easily because simcons is always statically linked, but
237  * other tty drivers that depend on tty_init and which must use
238  * `module_init' to declare their init routines are likely to be broken.
239  */
240 
241 late_initcall(rs_init);
242 
243 
244 #ifdef CONFIG_SERIAL_CONSOLE
245 
246 static void iss_console_write(struct console *co, const char *s, unsigned count)
247 {
248 	int len = strlen(s);
249 
250 	if (s != 0 && *s != 0)
251 		__simc (SYS_write, 1, (unsigned long)s,
252 			count < len ? count : len,0,0);
253 }
254 
255 static struct tty_driver* iss_console_device(struct console *c, int *index)
256 {
257 	*index = c->index;
258 	return serial_driver;
259 }
260 
261 
262 static struct console sercons = {
263 	.name = "ttyS",
264 	.write = iss_console_write,
265 	.device = iss_console_device,
266 	.flags = CON_PRINTBUFFER,
267 	.index = -1
268 };
269 
270 static int __init iss_console_init(void)
271 {
272 	register_console(&sercons);
273 	return 0;
274 }
275 
276 console_initcall(iss_console_init);
277 
278 #endif /* CONFIG_SERIAL_CONSOLE */
279 
280