console.c

  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
 34static void rs_poll(struct timer_list *);
 35
 36static struct tty_driver *serial_driver;
 37static struct tty_port serial_port;
 38static DEFINE_TIMER(serial_timer, rs_poll);
 39
 40static int rs_open(struct tty_struct *tty, struct file * filp)
 41{
 42	if (tty->count == 1)
 43		mod_timer(&serial_timer, jiffies + SERIAL_TIMER_VALUE);
 44
 45	return 0;
 46}
 47
 48static void rs_close(struct tty_struct *tty, struct file * filp)
 49{
 50	if (tty->count == 1)
 51		timer_delete_sync(&serial_timer);
 52}
 53
 54
 55static ssize_t rs_write(struct tty_struct * tty, const u8 *buf, size_t count)
 56{
 57	/* see drivers/char/serialX.c to reference original version */
 58
 59	simc_write(1, buf, count);
 60	return count;
 61}
 62
 63static void rs_poll(struct timer_list *unused)
 64{
 65	struct tty_port *port = &serial_port;
 66	int i = 0;
 67	int rd = 1;
 68	u8 c;
 69
 70	while (simc_poll(0)) {
 71		rd = simc_read(0, &c, 1);
 72		if (rd <= 0)
 73			break;
 74		tty_insert_flip_char(port, c, TTY_NORMAL);
 75		i++;
 76	}
 77
 78	if (i)
 79		tty_flip_buffer_push(port);
 80	if (rd)
 81		mod_timer(&serial_timer, jiffies + SERIAL_TIMER_VALUE);
 82}
 83
 84static unsigned int rs_write_room(struct tty_struct *tty)
 85{
 86	/* Let's say iss can always accept 2K characters.. */
 87	return 2 * 1024;
 88}
 89
 90static int rs_proc_show(struct seq_file *m, void *v)
 91{
 92	seq_printf(m, "serinfo:1.0 driver:0.1\n");
 93	return 0;
 94}
 95
 96static const struct tty_operations serial_ops = {
 97	.open = rs_open,
 98	.close = rs_close,
 99	.write = rs_write,
100	.write_room = rs_write_room,
101	.proc_show = rs_proc_show,
102};
103
104static int __init rs_init(void)
105{
106	struct tty_driver *driver;
107	int ret;
108
109	driver = tty_alloc_driver(SERIAL_MAX_NUM_LINES, TTY_DRIVER_REAL_RAW);
110	if (IS_ERR(driver))
111		return PTR_ERR(driver);
112
113	tty_port_init(&serial_port);
114
115	/* Initialize the tty_driver structure */
116
117	driver->driver_name = "iss_serial";
118	driver->name = "ttyS";
119	driver->major = TTY_MAJOR;
120	driver->minor_start = 64;
121	driver->type = TTY_DRIVER_TYPE_SERIAL;
122	driver->subtype = SERIAL_TYPE_NORMAL;
123	driver->init_termios = tty_std_termios;
124	driver->init_termios.c_cflag =
125		B9600 | CS8 | CREAD | HUPCL | CLOCAL;
126
127	tty_set_operations(driver, &serial_ops);
128	tty_port_link_device(&serial_port, driver, 0);
129
130	ret = tty_register_driver(driver);
131	if (ret) {
132		pr_err("Couldn't register serial driver\n");
133		tty_driver_kref_put(driver);
134		tty_port_destroy(&serial_port);
135
136		return ret;
137	}
138
139	serial_driver = driver;
140
141	return 0;
142}
143
144
145static __exit void rs_exit(void)
146{
147	tty_unregister_driver(serial_driver);
148	tty_driver_kref_put(serial_driver);
149	tty_port_destroy(&serial_port);
150}
151
152
153/* We use `late_initcall' instead of just `__initcall' as a workaround for
154 * the fact that (1) simcons_tty_init can't be called before tty_init,
155 * (2) tty_init is called via `module_init', (3) if statically linked,
156 * module_init == device_init, and (4) there's no ordering of init lists.
157 * We can do this easily because simcons is always statically linked, but
158 * other tty drivers that depend on tty_init and which must use
159 * `module_init' to declare their init routines are likely to be broken.
160 */
161
162late_initcall(rs_init);
163
164
165#ifdef CONFIG_SERIAL_CONSOLE
166
167static void iss_console_write(struct console *co, const char *s, unsigned count)
168{
169	if (s && *s != 0)
170		simc_write(1, s, min(count, strlen(s)));
171}
172
173static struct tty_driver* iss_console_device(struct console *c, int *index)
174{
175	*index = c->index;
176	return serial_driver;
177}
178
179
180static struct console sercons = {
181	.name = "ttyS",
182	.write = iss_console_write,
183	.device = iss_console_device,
184	.flags = CON_PRINTBUFFER,
185	.index = -1
186};
187
188static int __init iss_console_init(void)
189{
190	register_console(&sercons);
191	return 0;
192}
193
194console_initcall(iss_console_init);
195
196#endif /* CONFIG_SERIAL_CONSOLE */
197