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