/arch/xtensa/platforms/iss/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#include <linux/serialP.h>
 23
 24#include <asm/uaccess.h>
 25#include <asm/irq.h>
 26
 27#include <platform/simcall.h>
 28
 29#include <linux/tty.h>
 30#include <linux/tty_flip.h>
 31
 32#ifdef SERIAL_INLINE
 33#define _INLINE_ inline
 34#endif
 35
 36#define SERIAL_MAX_NUM_LINES 1
 37#define SERIAL_TIMER_VALUE (20 * HZ)
 38
 39static struct tty_driver *serial_driver;
 40static struct timer_list serial_timer;
 41
 42static DEFINE_SPINLOCK(timer_lock);
 43
 44int errno;
 45
 46static int __simc (int a, int b, int c, int d, int e, int f) __attribute__((__noinline__));
 47static int __simc (int a, int b, int c, int d, int e, int f)
 48{
 49	int ret;
 50	__asm__ __volatile__ ("simcall\n"
 51			"mov %0, a2\n"
 52			"mov %1, a3\n" : "=a" (ret), "=a" (errno)
 53			: : "a2", "a3");
 54	return ret;
 55}
 56
 57static char *serial_version = "0.1";
 58static char *serial_name = "ISS serial driver";
 59
 60/*
 61 * This routine is called whenever a serial port is opened.  It
 62 * enables interrupts for a serial port, linking in its async structure into
 63 * the IRQ chain.   It also performs the serial-specific
 64 * initialization for the tty structure.
 65 */
 66
 67static void rs_poll(unsigned long);
 68
 69static int rs_open(struct tty_struct *tty, struct file * filp)
 70{
 71	int line = tty->index;
 72
 73	if ((line < 0) || (line >= SERIAL_MAX_NUM_LINES))
 74		return -ENODEV;
 75
 76	spin_lock(&timer_lock);
 77
 78	if (tty->count == 1) {
 79		init_timer(&serial_timer);
 80		serial_timer.data = (unsigned long) tty;
 81		serial_timer.function = rs_poll;
 82		mod_timer(&serial_timer, jiffies + SERIAL_TIMER_VALUE);
 83	}
 84	spin_unlock(&timer_lock);
 85
 86	return 0;
 87}
 88
 89
 90/*
 91 * ------------------------------------------------------------
 92 * iss_serial_close()
 93 *
 94 * This routine is called when the serial port gets closed.  First, we
 95 * wait for the last remaining data to be sent.  Then, we unlink its
 96 * async structure from the interrupt chain if necessary, and we free
 97 * that IRQ if nothing is left in the chain.
 98 * ------------------------------------------------------------
 99 */
100static void rs_close(struct tty_struct *tty, struct file * filp)
101{
102	spin_lock(&timer_lock);
103	if (tty->count == 1)
104		del_timer_sync(&serial_timer);
105	spin_unlock(&timer_lock);
106}
107
108
109static int rs_write(struct tty_struct * tty,
110		    const unsigned char *buf, int count)
111{
112	/* see drivers/char/serialX.c to reference original version */
113
114	__simc (SYS_write, 1, (unsigned long)buf, count, 0, 0);
115	return count;
116}
117
118static void rs_poll(unsigned long priv)
119{
120	struct tty_struct* tty = (struct tty_struct*) priv;
121
122	struct timeval tv = { .tv_sec = 0, .tv_usec = 0 };
123	int i = 0;
124	unsigned char c;
125
126	spin_lock(&timer_lock);
127
128	while (__simc(SYS_select_one, 0, XTISS_SELECT_ONE_READ, (int)&tv,0,0)){
129		__simc (SYS_read, 0, (unsigned long)&c, 1, 0, 0);
130		tty_insert_flip_char(tty, c, TTY_NORMAL);
131		i++;
132	}
133
134	if (i)
135		tty_flip_buffer_push(tty);
136
137
138	mod_timer(&serial_timer, jiffies + SERIAL_TIMER_VALUE);
139	spin_unlock(&timer_lock);
140}
141
142
143static int rs_put_char(struct tty_struct *tty, unsigned char ch)
144{
145	char buf[2];
146
147	buf[0] = ch;
148	buf[1] = '\0';		/* Is this NULL necessary? */
149	__simc (SYS_write, 1, (unsigned long) buf, 1, 0, 0);
150	return 1;
151}
152
153static void rs_flush_chars(struct tty_struct *tty)
154{
155}
156
157static int rs_write_room(struct tty_struct *tty)
158{
159	/* Let's say iss can always accept 2K characters.. */
160	return 2 * 1024;
161}
162
163static int rs_chars_in_buffer(struct tty_struct *tty)
164{
165	/* the iss doesn't buffer characters */
166	return 0;
167}
168
169static void rs_hangup(struct tty_struct *tty)
170{
171	/* Stub, once again.. */
172}
173
174static void rs_wait_until_sent(struct tty_struct *tty, int timeout)
175{
176	/* Stub, once again.. */
177}
178
179static int rs_proc_show(struct seq_file *m, void *v)
180{
181	seq_printf(m, "serinfo:1.0 driver:%s\n", serial_version);
182	return 0;
183}
184
185static int rs_proc_open(struct inode *inode, struct file *file)
186{
187	return single_open(file, rs_proc_show, NULL);
188}
189
190static const struct file_operations rs_proc_fops = {
191	.owner		= THIS_MODULE,
192	.open		= rs_proc_open,
193	.read		= seq_read,
194	.llseek		= seq_lseek,
195	.release	= single_release,
196};
197
198static const struct tty_operations serial_ops = {
199	.open = rs_open,
200	.close = rs_close,
201	.write = rs_write,
202	.put_char = rs_put_char,
203	.flush_chars = rs_flush_chars,
204	.write_room = rs_write_room,
205	.chars_in_buffer = rs_chars_in_buffer,
206	.hangup = rs_hangup,
207	.wait_until_sent = rs_wait_until_sent,
208	.proc_fops = &rs_proc_fops,
209};
210
211int __init rs_init(void)
212{
213	serial_driver = alloc_tty_driver(1);
214
215	printk ("%s %s\n", serial_name, serial_version);
216
217	/* Initialize the tty_driver structure */
218
219	serial_driver->owner = THIS_MODULE;
220	serial_driver->driver_name = "iss_serial";
221	serial_driver->name = "ttyS";
222	serial_driver->major = TTY_MAJOR;
223	serial_driver->minor_start = 64;
224	serial_driver->type = TTY_DRIVER_TYPE_SERIAL;
225	serial_driver->subtype = SERIAL_TYPE_NORMAL;
226	serial_driver->init_termios = tty_std_termios;
227	serial_driver->init_termios.c_cflag =
228		B9600 | CS8 | CREAD | HUPCL | CLOCAL;
229	serial_driver->flags = TTY_DRIVER_REAL_RAW;
230
231	tty_set_operations(serial_driver, &serial_ops);
232
233	if (tty_register_driver(serial_driver))
234		panic("Couldn't register serial driver\n");
235	return 0;
236}
237
238
239static __exit void rs_exit(void)
240{
241	int error;
242
243	if ((error = tty_unregister_driver(serial_driver)))
244		printk("ISS_SERIAL: failed to unregister serial driver (%d)\n",
245		       error);
246	put_tty_driver(serial_driver);
247}
248
249
250/* We use `late_initcall' instead of just `__initcall' as a workaround for
251 * the fact that (1) simcons_tty_init can't be called before tty_init,
252 * (2) tty_init is called via `module_init', (3) if statically linked,
253 * module_init == device_init, and (4) there's no ordering of init lists.
254 * We can do this easily because simcons is always statically linked, but
255 * other tty drivers that depend on tty_init and which must use
256 * `module_init' to declare their init routines are likely to be broken.
257 */
258
259late_initcall(rs_init);
260
261
262#ifdef CONFIG_SERIAL_CONSOLE
263
264static void iss_console_write(struct console *co, const char *s, unsigned count)
265{
266	int len = strlen(s);
267
268	if (s != 0 && *s != 0)
269		__simc (SYS_write, 1, (unsigned long)s,
270			count < len ? count : len,0,0);
271}
272
273static struct tty_driver* iss_console_device(struct console *c, int *index)
274{
275	*index = c->index;
276	return serial_driver;
277}
278
279
280static struct console sercons = {
281	.name = "ttyS",
282	.write = iss_console_write,
283	.device = iss_console_device,
284	.flags = CON_PRINTBUFFER,
285	.index = -1
286};
287
288static int __init iss_console_init(void)
289{
290	register_console(&sercons);
291	return 0;
292}
293
294console_initcall(iss_console_init);
295
296#endif /* CONFIG_SERIAL_CONSOLE */
297