serial_amba.c

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			break;
		if (timeout && time_after(jiffies, expire))
			break;
		status = UART_GET_FR(info->port);
	}
	set_current_state(TASK_RUNNING);
}

static void ambauart_hangup(struct tty_struct *tty)
{
	struct amba_info *info = tty->driver_data;
	struct amba_state *state = info->state;

	ambauart_flush_buffer(tty);
	if (info->flags & ASYNC_CLOSING)
		return;
	ambauart_shutdown(info);
	info->event = 0;
	state->count = 0;
	info->flags &= ~(ASYNC_NORMAL_ACTIVE|ASYNC_CALLOUT_ACTIVE);
	info->tty = NULL;
	wake_up_interruptible(&info->open_wait);
}

static int block_til_ready(struct tty_struct *tty, struct file *filp,
			   struct amba_info *info)
{
	DECLARE_WAITQUEUE(wait, current);
	struct amba_state *state = info->state;
	unsigned long flags;
	int do_clocal = 0, extra_count = 0, retval;

	/*
	 * If the device is in the middle of being closed, then block
	 * until it's done, and then try again.
	 */
	if (tty_hung_up_p(filp) ||
	    (info->flags & ASYNC_CLOSING)) {
		if (info->flags & ASYNC_CLOSING)
			interruptible_sleep_on(&info->close_wait);
		return (info->flags & ASYNC_HUP_NOTIFY) ?
			-EAGAIN : -ERESTARTSYS;
	}

	/*
	 * If this is a callout device, then just make sure the normal
	 * device isn't being used.
	 */
	if (tty->driver.subtype == SERIAL_TYPE_CALLOUT) {
		if (info->flags & ASYNC_NORMAL_ACTIVE)
			return -EBUSY;
		if ((info->flags & ASYNC_CALLOUT_ACTIVE) &&
		    (info->flags & ASYNC_SESSION_LOCKOUT) &&
		    (info->session != current->session))
			return -EBUSY;
		if ((info->flags & ASYNC_CALLOUT_ACTIVE) &&
		    (info->flags & ASYNC_PGRP_LOCKOUT) &&
		    (info->pgrp != current->pgrp))
			return -EBUSY;
		info->flags |= ASYNC_CALLOUT_ACTIVE;
		return 0;
	}

	/*
	 * If non-blocking mode is set, or the port is not enabled,
	 * then make the check up front and then exit.
	 */
	if ((filp->f_flags & O_NONBLOCK) ||
	    (tty->flags & (1 << TTY_IO_ERROR))) {
		if (info->flags & ASYNC_CALLOUT_ACTIVE)
			return -EBUSY;
		info->flags |= ASYNC_NORMAL_ACTIVE;
		return 0;
	}

	if (info->flags & ASYNC_CALLOUT_ACTIVE) {
		if (state->normal_termios.c_cflag & CLOCAL)
			do_clocal = 1;
	} else {
		if (tty->termios->c_cflag & CLOCAL)
			do_clocal = 1;
	}

	/*
	 * Block waiting for the carrier detect and the line to become
	 * free (i.e., not in use by the callout).  While we are in
	 * this loop, state->count is dropped by one, so that
	 * rs_close() knows when to free things.  We restore it upon
	 * exit, either normal or abnormal.
	 */
	retval = 0;
	add_wait_queue(&info->open_wait, &wait);
	save_flags(flags); cli();
	if (!tty_hung_up_p(filp)) {
		extra_count = 1;
		state->count--;
	}
	restore_flags(flags);
	info->blocked_open++;
	while (1) {
		save_flags(flags); cli();
		if (!(info->flags & ASYNC_CALLOUT_ACTIVE) &&
		    (tty->termios->c_cflag & CBAUD)) {
			info->mctrl = TIOCM_DTR | TIOCM_RTS;
			info->port->set_mctrl(info->port, info->mctrl);
		}
		restore_flags(flags);
		set_current_state(TASK_INTERRUPTIBLE);
		if (tty_hung_up_p(filp) ||
		    !(info->flags & ASYNC_INITIALIZED)) {
			if (info->flags & ASYNC_HUP_NOTIFY)
				retval = -EAGAIN;
			else
				retval = -ERESTARTSYS;
			break;
		}
		if (!(info->flags & ASYNC_CALLOUT_ACTIVE) &&
		    !(info->flags & ASYNC_CLOSING) &&
		    (do_clocal || (UART_GET_FR(info->port) & AMBA_UARTFR_DCD)))
			break;
		if (signal_pending(current)) {
			retval = -ERESTARTSYS;
			break;
		}
		schedule();
	}
	set_current_state(TASK_RUNNING);
	remove_wait_queue(&info->open_wait, &wait);
	if (extra_count)
		state->count++;
	info->blocked_open--;
	if (retval)
		return retval;
	info->flags |= ASYNC_NORMAL_ACTIVE;
	return 0;
}

static struct amba_info *ambauart_get(int line)
{
	struct amba_info *info;
	struct amba_state *state = amba_state + line;

	state->count++;
	if (state->info)
		return state->info;
	info = kmalloc(sizeof(struct amba_info), GFP_KERNEL);
	if (info) {
		memset(info, 0, sizeof(struct amba_info));
		init_waitqueue_head(&info->open_wait);
		init_waitqueue_head(&info->close_wait);
		init_waitqueue_head(&info->delta_msr_wait);
		info->flags = state->flags;
		info->state = state;
		info->port  = amba_ports + line;
		tasklet_init(&info->tlet, ambauart_tasklet_action,
			     (unsigned long)info);
	}
	if (state->info) {
		kfree(info);
		return state->info;
	}
	state->info = info;
	return info;
}

static int ambauart_open(struct tty_struct *tty, struct file *filp)
{
	struct amba_info *info;
	int retval, line = MINOR(tty->device) - tty->driver.minor_start;

#if DEBUG
	printk("ambauart_open(%d) called\n", line);
#endif

	// is this a line that we've got?
	MOD_INC_USE_COUNT;
	if (line >= SERIAL_AMBA_NR) {
		MOD_DEC_USE_COUNT;
		return -ENODEV;
	}

	info = ambauart_get(line);
	if (!info)
		return -ENOMEM;

	tty->driver_data = info;
	info->tty = tty;
	info->tty->low_latency = (info->flags & ASYNC_LOW_LATENCY) ? 1 : 0;

	/*
	 * Make sure we have the temporary buffer allocated
	 */
	if (!tmp_buf) {
		unsigned long page = get_zeroed_page(GFP_KERNEL);
		if (tmp_buf)
			free_page(page);
		else if (!page) {
			MOD_DEC_USE_COUNT;
			return -ENOMEM;
		}
		tmp_buf = (u_char *)page;
	}

	/*
	 * If the port is in the middle of closing, bail out now.
	 */
	if (tty_hung_up_p(filp) ||
	    (info->flags & ASYNC_CLOSING)) {
		if (info->flags & ASYNC_CLOSING)
			interruptible_sleep_on(&info->close_wait);
		MOD_DEC_USE_COUNT;
		return -EAGAIN;
	}

	/*
	 * Start up the serial port
	 */
	retval = ambauart_startup(info);
	if (retval) {
		MOD_DEC_USE_COUNT;
		return retval;
	}

	retval = block_til_ready(tty, filp, info);
	if (retval) {
		MOD_DEC_USE_COUNT;
		return retval;
	}

	if ((info->state->count == 1) &&
	    (info->flags & ASYNC_SPLIT_TERMIOS)) {
		if (tty->driver.subtype == SERIAL_TYPE_NORMAL)
			*tty->termios = info->state->normal_termios;
		else
			*tty->termios = info->state->callout_termios;
	}
#ifdef CONFIG_SERIAL_AMBA_CONSOLE
	if (ambauart_cons.cflag && ambauart_cons.index == line) {
		tty->termios->c_cflag = ambauart_cons.cflag;
		ambauart_cons.cflag = 0;
	}
#endif
	ambauart_change_speed(info, NULL);
	info->session = current->session;
	info->pgrp = current->pgrp;
	return 0;
}

int __init ambauart_init(void)
{
	int i;

	ambanormal_driver.magic = TTY_DRIVER_MAGIC;
	ambanormal_driver.driver_name = "serial_amba";
	ambanormal_driver.name = SERIAL_AMBA_NAME;
	ambanormal_driver.major = SERIAL_AMBA_MAJOR;
	ambanormal_driver.minor_start = SERIAL_AMBA_MINOR;
	ambanormal_driver.num = SERIAL_AMBA_NR;
	ambanormal_driver.type = TTY_DRIVER_TYPE_SERIAL;
	ambanormal_driver.subtype = SERIAL_TYPE_NORMAL;
	ambanormal_driver.init_termios = tty_std_termios;
	ambanormal_driver.init_termios.c_cflag = B38400 | CS8 | CREAD | HUPCL | CLOCAL;
	ambanormal_driver.flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_NO_DEVFS;
	ambanormal_driver.refcount = &ambauart_refcount;
	ambanormal_driver.table = ambauart_table;
	ambanormal_driver.termios = ambauart_termios;
	ambanormal_driver.termios_locked = ambauart_termios_locked;

	ambanormal_driver.open = ambauart_open;
	ambanormal_driver.close = ambauart_close;
	ambanormal_driver.write = ambauart_write;
	ambanormal_driver.put_char = ambauart_put_char;
	ambanormal_driver.flush_chars = ambauart_flush_chars;
	ambanormal_driver.write_room = ambauart_write_room;
	ambanormal_driver.chars_in_buffer = ambauart_chars_in_buffer;
	ambanormal_driver.flush_buffer	= ambauart_flush_buffer;
	ambanormal_driver.ioctl = ambauart_ioctl;
	ambanormal_driver.throttle = ambauart_throttle;
	ambanormal_driver.unthrottle = ambauart_unthrottle;
	ambanormal_driver.send_xchar = ambauart_send_xchar;
	ambanormal_driver.set_termios = ambauart_set_termios;
	ambanormal_driver.stop = ambauart_stop;
	ambanormal_driver.start = ambauart_start;
	ambanormal_driver.hangup = ambauart_hangup;
	ambanormal_driver.break_ctl = ambauart_break_ctl;
	ambanormal_driver.wait_until_sent = ambauart_wait_until_sent;
	ambanormal_driver.read_proc = NULL;

	/*
	 * The callout device is just like the normal device except for
	 * the major number and the subtype code.
	 */
	ambacallout_driver = ambanormal_driver;
	ambacallout_driver.name = CALLOUT_AMBA_NAME;
	ambacallout_driver.major = CALLOUT_AMBA_MAJOR;
	ambacallout_driver.subtype = SERIAL_TYPE_CALLOUT;
	ambacallout_driver.read_proc = NULL;
	ambacallout_driver.proc_entry = NULL;

	if (tty_register_driver(&ambanormal_driver))
		panic("Couldn't register AMBA serial driver\n");
	if (tty_register_driver(&ambacallout_driver))
		panic("Couldn't register AMBA callout driver\n");

	for (i = 0; i < SERIAL_AMBA_NR; i++) {
		struct amba_state *state = amba_state + i;
		state->line		= i;
		state->close_delay	= 5 * HZ / 10;
		state->closing_wait	= 30 * HZ;
		state->callout_termios	= ambacallout_driver.init_termios;
		state->normal_termios	= ambanormal_driver.init_termios;
	}

	return 0;
}

__initcall(ambauart_init);

#ifdef CONFIG_SERIAL_AMBA_CONSOLE
/************** console driver *****************/

/*
 * This code is currently never used; console->read is never called.
 * Therefore, although we have an implementation, we don't use it.
 * FIXME: the "const char *s" should be fixed to "char *s" some day.
 * (when the definition in include/linux/console.h is also fixed)
 */
#ifdef used_and_not_const_char_pointer
static int ambauart_console_read(struct console *co, const char *s, u_int count)
{
	struct amba_port *port = &amba_ports[co->index];
	unsigned int status;
	char *w;
	int c;
#if DEBUG
	printk("ambauart_console_read() called\n");
#endif

	c = 0;
	w = s;
	while (c < count) {
		status = UART_GET_FR(port);
		if (UART_RX_DATA(status)) {
			*w++ = UART_GET_CHAR(port);
			c++;
		} else {
			// nothing more to get, return
			return c;
		}
	}
	// return the count
	return c;
}
#endif

/*
 *	Print a string to the serial port trying not to disturb
 *	any possible real use of the port...
 *
 *	The console_lock must be held when we get here.
 */
static void ambauart_console_write(struct console *co, const char *s, u_int count)
{
	struct amba_port *port = &amba_ports[co->index];
	unsigned int status, old_cr;
	int i;

	/*
	 *	First save the CR then disable the interrupts
	 */
	old_cr = UART_GET_CR(port);
	UART_PUT_CR(port, AMBA_UARTCR_UARTEN);

	/*
	 *	Now, do each character
	 */
	for (i = 0; i < count; i++) {
		do {
			status = UART_GET_FR(port);
		} while (!UART_TX_READY(status));
		UART_PUT_CHAR(port, s[i]);
		if (s[i] == '\n') {
			do {
				status = UART_GET_FR(port);
			} while (!UART_TX_READY(status));
			UART_PUT_CHAR(port, '\r');
		}
	}

	/*
	 *	Finally, wait for transmitter to become empty
	 *	and restore the TCR
	 */
	do {
		status = UART_GET_FR(port);
	} while (status & AMBA_UARTFR_BUSY);
	UART_PUT_CR(port, old_cr);
}

/*
 *	Receive character from the serial port
 */
static int ambauart_console_wait_key(struct console *co)
{
	struct amba_port *port = &amba_ports[co->index];
	unsigned int status;
	int c;

	do {
		status = UART_GET_FR(port);
	} while (!UART_RX_DATA(status));
	c = UART_GET_CHAR(port);
	return c;
}

static kdev_t ambauart_console_device(struct console *c)
{
	return MKDEV(SERIAL_AMBA_MAJOR, SERIAL_AMBA_MINOR + c->index);
}

static int __init ambauart_console_setup(struct console *co, char *options)
{
	struct amba_port *port;
	int baud = 38400;
	int bits = 8;
	int parity = 'n';
	u_int cflag = CREAD | HUPCL | CLOCAL;
	u_int lcr_h, quot;

	if (co->index >= SERIAL_AMBA_NR)
		co->index = 0;

	port = &amba_ports[co->index];

	if (options) {
		char *s = options;
		baud = simple_strtoul(s, NULL, 10);
		while (*s >= '0' && *s <= '9')
			s++;
		if (*s) parity = *s++;
		if (*s) bits = *s - '0';
	}

	/*
	 *    Now construct a cflag setting.
	 */
	switch (baud) {
	case 1200:	cflag |= B1200;			break;
	case 2400:	cflag |= B2400;			break;
	case 4800:	cflag |= B4800;			break;
	default:	cflag |= B9600;   baud = 9600;	break;
	case 19200:	cflag |= B19200;		break;
	case 38400:	cflag |= B38400;		break;
	case 57600:	cflag |= B57600;		break;
	case 115200:	cflag |= B115200;		break;
	}
	switch (bits) {
	case 7:	  cflag |= CS7;	lcr_h = AMBA_UARTLCR_H_WLEN_7;	break;
	default:  cflag |= CS8;	lcr_h = AMBA_UARTLCR_H_WLEN_8;	break;
	}
	switch (parity) {
	case 'o':
	case 'O': cflag |= PARODD; lcr_h |= AMBA_UARTLCR_H_PEN;	break;
	case 'e':
	case 'E': cflag |= PARENB; lcr_h |= AMBA_UARTLCR_H_PEN |
					    AMBA_UARTLCR_H_EPS; break;
	}

	co->cflag = cflag;

	if (port->fifosize > 1)
		lcr_h |= AMBA_UARTLCR_H_FEN;

	quot = (port->uartclk / (16 * baud)) - 1;

	UART_PUT_LCRL(port, (quot & 0xff));
	UART_PUT_LCRM(port, (quot >> 8));
	UART_PUT_LCRH(port, lcr_h);

	/* we will enable the port as we need it */
	UART_PUT_CR(port, 0);

	return 0;
}

static struct console ambauart_cons =
{
	name:		SERIAL_AMBA_NAME,
	write:		ambauart_console_write,
#ifdef used_and_not_const_char_pointer
	read:		ambauart_console_read,
#endif
	device:		ambauart_console_device,
	wait_key:	ambauart_console_wait_key,
	setup:		ambauart_console_setup,
	flags:		CON_PRINTBUFFER,
	index:		-1,
};

void __init ambauart_console_init(void)
{
	register_console(&ambauart_cons);
}

#endif /* CONFIG_SERIAL_AMBA_CONSOLE */