con3215.c

讲述linux的初始化过程

	raw3215_info *raw;

	if (count <= 0)
		return;
	raw = raw3215[0];  /* console 3215 is the first one */
	raw3215_write(raw, str, 0, count);
}

kdev_t con3215_device(struct console *c)
{
	return MKDEV(TTY_MAJOR, c->index);
}

/*
 * panic() calls console_unblank before the system enters a
 * disabled, endless loop.
 */
void con3215_unblank(void)
{
	raw3215_info *raw;
	unsigned long flags;

	raw = raw3215[0];  /* console 3215 is the first one */
	s390irq_spin_lock_irqsave(raw->irq, flags);
	while (raw->count > 0) {
		/* there might be a request pending */
		raw->flags |= RAW3215_FLUSHING;
		raw3215_try_io(raw);
		if (wait_cons_dev(raw->irq) != 0) {
			/* that shouldn't happen */
			raw->count = 0;
		}
		raw->flags &= ~RAW3215_FLUSHING;
	}
	s390irq_spin_unlock_irqrestore(raw->irq, flags);
}

static int __init con3215_consetup(struct console *co, char *options)
{
	return 0;
}

/*
 *  The console structure for the 3215 console
 */
static struct console con3215 = {
	name:		"tty3215",
	write:		con3215_write,
	device:		con3215_device,
	unblank:	con3215_unblank,
	setup:		con3215_consetup,
	flags:		CON_PRINTBUFFER,
};

#endif

/*
 * tty3215_open
 *
 * This routine is called whenever a 3215 tty is opened.
 */
static int tty3215_open(struct tty_struct *tty, struct file * filp)
{
	raw3215_info *raw;
	int retval, line;

	line = MINOR(tty->device) - tty->driver.minor_start;
	if ((line < 0) || (line >= NR_3215))
		return -ENODEV;

	raw = raw3215[line];
	if (raw == NULL) {
		raw = kmalloc(sizeof(raw3215_info) +
			      RAW3215_INBUF_SIZE, GFP_KERNEL);
		if (raw == NULL)
			return -ENOMEM;
		raw->irq = raw3215_find_dev(line);
		if (raw->irq == -1) {
			kfree(raw);
			return -ENODEV;
		}
		raw->inbuf = (char *) raw + sizeof(raw3215_info);
		memset(raw, 0, sizeof(raw3215_info));
		raw->buffer = (char *) kmalloc(RAW3215_BUFFER_SIZE, GFP_KERNEL);
		if (raw->buffer == NULL) {
			kfree(raw);
			return -ENOMEM;
		}
		raw->tqueue.routine = raw3215_softint;
		raw->tqueue.data = raw;
                init_waitqueue_head(&raw->empty_wait);
		raw3215[line] = raw;
	}

	tty->driver_data = raw;
	raw->tty = tty;

	tty->low_latency = 0;  /* don't use bottom half for pushing chars */
	/*
	 * Start up 3215 device
	 */
	retval = raw3215_startup(raw);
	if (retval)
		return retval;

	return 0;
}

/*
 * tty3215_close()
 *
 * This routine is called when the 3215 tty is closed. We wait
 * for the remaining request to be completed. Then we clean up.
 */
static void tty3215_close(struct tty_struct *tty, struct file * filp)
{
	raw3215_info *raw;

	raw = (raw3215_info *) tty->driver_data;
	if (raw == NULL || tty->count > 1)
		return;
	tty->closing = 1;
	/* Shutdown the terminal */
	raw3215_shutdown(raw);
	tty->closing = 0;
	raw->tty = NULL;
}

/*
 * Returns the amount of free space in the output buffer.
 */
static int tty3215_write_room(struct tty_struct *tty)
{
	raw3215_info *raw;
				
	raw = (raw3215_info *) tty->driver_data;
	return RAW3215_BUFFER_SIZE - raw->count;
}

/*
 * String write routine for 3215 ttys
 */
static int tty3215_write(struct tty_struct * tty, int from_user,
		    const unsigned char *buf, int count)
{
	raw3215_info *raw;
	int ret;
				
	if (!tty)
		return 0;
	raw = (raw3215_info *) tty->driver_data;
	ret = raw3215_write(raw, buf, from_user, count);
	return ret;
}

/*
 * Put character routine for 3215 ttys
 */
static void tty3215_put_char(struct tty_struct *tty, unsigned char ch)
{
	raw3215_info *raw;

	if (!tty)
		return;
	raw = (raw3215_info *) tty->driver_data;
	raw3215_putchar(raw, ch);
}

static void tty3215_flush_chars(struct tty_struct *tty)
{
}

/*
 * Returns the number of characters in the output buffer
 */
static int tty3215_chars_in_buffer(struct tty_struct *tty)
{
	raw3215_info *raw;

	raw = (raw3215_info *) tty->driver_data;
	return raw->count;
}

static void tty3215_flush_buffer(struct tty_struct *tty)
{
	raw3215_info *raw;

	raw = (raw3215_info *) tty->driver_data;
	raw3215_flush_buffer(raw);
	wake_up_interruptible(&tty->write_wait);
	if ((tty->flags & (1 << TTY_DO_WRITE_WAKEUP)) &&
	    tty->ldisc.write_wakeup)
		(tty->ldisc.write_wakeup)(tty);
}

/*
 * Currently we don't have any io controls for 3215 ttys
 */
static int tty3215_ioctl(struct tty_struct *tty, struct file * file,
		    unsigned int cmd, unsigned long arg)
{
	if (tty->flags & (1 << TTY_IO_ERROR))
		return -EIO;

	switch (cmd) {
	default:
		return -ENOIOCTLCMD;
	}
	return 0;
}

/*
 * Disable reading from a 3215 tty
 */
static void tty3215_throttle(struct tty_struct * tty)
{
	raw3215_info *raw;

	raw = (raw3215_info *) tty->driver_data;
	raw->flags |= RAW3215_THROTTLED;
}

/*
 * Enable reading from a 3215 tty
 */
static void tty3215_unthrottle(struct tty_struct * tty)
{
	raw3215_info *raw;
	unsigned long flags;

	raw = (raw3215_info *) tty->driver_data;
	if (raw->flags & RAW3215_THROTTLED) {
		s390irq_spin_lock_irqsave(raw->irq, flags);
		raw->flags &= ~RAW3215_THROTTLED;
		raw3215_try_io(raw);
		s390irq_spin_unlock_irqrestore(raw->irq, flags);
	}
}

/*
 * Disable writing to a 3215 tty
 */
static void tty3215_stop(struct tty_struct *tty)
{
	raw3215_info *raw;

	raw = (raw3215_info *) tty->driver_data;
	raw->flags |= RAW3215_STOPPED;
}

/*
 * Enable writing to a 3215 tty
 */
static void tty3215_start(struct tty_struct *tty)
{
	raw3215_info *raw;
	unsigned long flags;

	raw = (raw3215_info *) tty->driver_data;
	if (raw->flags & RAW3215_STOPPED) {
		s390irq_spin_lock_irqsave(raw->irq, flags);
		raw->flags &= ~RAW3215_STOPPED;
		raw3215_try_io(raw);
		s390irq_spin_unlock_irqrestore(raw->irq, flags);
	}
}

/*
 * 3215 console driver boottime initialization code.
 * Register console. We can't request the IRQ here, because
 * it's too early (kmalloc isn't working yet). We'll have to
 * buffer all the console requests until we can request the
 * irq. For this purpose we use some pages of fixed memory.
 */
void __init con3215_init(void)
{
	raw3215_info *raw;
	raw3215_req *req;
	int i;

	if (!MACHINE_IS_VM && !MACHINE_IS_P390)
                return;
        if (MACHINE_IS_VM) {
	        cpcmd("TERM CONMODE 3215", NULL, 0);
	        cpcmd("TERM AUTOCR OFF", NULL, 0);
        }

	/* allocate 3215 request structures */
	raw3215_freelist = NULL;
	spin_lock_init(&raw3215_freelist_lock);
	for (i = 0; i < NR_3215_REQ; i++) {
		req = (raw3215_req *) alloc_bootmem(sizeof(raw3215_req));
		req->next = raw3215_freelist;
		raw3215_freelist = req;
	}

#ifdef CONFIG_3215_CONSOLE
	raw3215[0] = raw = (raw3215_info *) 
		alloc_bootmem(sizeof(raw3215_info));
	memset(raw, 0, sizeof(raw3215_info));
	raw->buffer = (char *) alloc_bootmem(RAW3215_BUFFER_SIZE);
	raw->inbuf = (char *) alloc_bootmem(RAW3215_INBUF_SIZE);
	/* Find the first console */
	raw->irq = raw3215_find_dev(0);
	raw->flags |= RAW3215_FIXED;
	raw->tqueue.routine = raw3215_softint;
	raw->tqueue.data = raw;
        init_waitqueue_head(&raw->empty_wait);

	if (raw->irq != -1) {
		register_console(&con3215);
		s390irq_spin_lock(raw->irq);
		set_cons_dev(raw->irq);
		s390irq_spin_unlock(raw->irq);
	} else {
		free_bootmem((unsigned long) raw->inbuf, RAW3215_INBUF_SIZE);
		free_bootmem((unsigned long) raw->buffer, RAW3215_BUFFER_SIZE);
		free_bootmem((unsigned long) raw, sizeof(raw3215_info));
		raw3215[0] = NULL;
		printk("Couldn't find a 3215 console device\n");
	}
#endif

	/*
	 * Initialize the tty_driver structure
	 * Entries in tty3215_driver that are NOT initialized:
	 * proc_entry, set_termios, flush_buffer, set_ldisc, write_proc
	 */

	memset(&tty3215_driver, 0, sizeof(struct tty_driver));
	tty3215_driver.magic = TTY_DRIVER_MAGIC;
	tty3215_driver.driver_name = "tty3215";
	tty3215_driver.name = "ttyS";
	tty3215_driver.name_base = 0;
	tty3215_driver.major = TTY_MAJOR;
	tty3215_driver.minor_start = 64;
	tty3215_driver.num = NR_3215;
	tty3215_driver.type = TTY_DRIVER_TYPE_SYSTEM;
	tty3215_driver.subtype = SYSTEM_TYPE_TTY;
	tty3215_driver.init_termios = tty_std_termios;
	tty3215_driver.init_termios.c_iflag = IGNBRK | IGNPAR;
	tty3215_driver.init_termios.c_oflag = ONLCR;
	tty3215_driver.init_termios.c_lflag = ISIG;
	tty3215_driver.flags = TTY_DRIVER_REAL_RAW;
	tty3215_driver.refcount = &tty3215_refcount;
	tty3215_driver.table = tty3215_table;
	tty3215_driver.termios = tty3215_termios;
	tty3215_driver.termios_locked = tty3215_termios_locked;

	tty3215_driver.open = tty3215_open;
	tty3215_driver.close = tty3215_close;
	tty3215_driver.write = tty3215_write;
	tty3215_driver.put_char = tty3215_put_char;
	tty3215_driver.flush_chars = tty3215_flush_chars;
	tty3215_driver.write_room = tty3215_write_room;
	tty3215_driver.chars_in_buffer = tty3215_chars_in_buffer;
	tty3215_driver.flush_buffer = tty3215_flush_buffer;
	tty3215_driver.ioctl = tty3215_ioctl;
	tty3215_driver.throttle = tty3215_throttle;
	tty3215_driver.unthrottle = tty3215_unthrottle;
	tty3215_driver.send_xchar = NULL;
	tty3215_driver.set_termios = NULL;
	tty3215_driver.stop = tty3215_stop;
	tty3215_driver.start = tty3215_start;
	tty3215_driver.hangup = NULL;
	tty3215_driver.break_ctl = NULL;
	tty3215_driver.wait_until_sent = NULL;
	tty3215_driver.read_proc = NULL;

	if (tty_register_driver(&tty3215_driver))
		panic("Couldn't register tty3215 driver\n");

}