mx21_16c2552.c

arm926e的mx21处理器的串口驱动程序

	if (copy_to_user(retinfo, &tmp, sizeof(*retinfo)))
		return -EFAULT;
	return 0;
}

static int set_serial_info(struct amba_info *info,
			   struct serial_struct *newinfo)
{
	struct serial_struct new_serial;
	struct amba_state *state, old_state;
	struct amba_port *port;
	unsigned long new_port;
	unsigned int i, change_irq, change_port;
	int retval = 0;

	if (copy_from_user(&new_serial, newinfo, sizeof(new_serial)))
		return -EFAULT;

	state = info->state;
	old_state = *state;
	port = info->port;

	new_port = new_serial.port;
	if (HIGH_BITS_OFFSET)
		new_port += (unsigned long) new_serial.port_high << HIGH_BITS_OFFSET;

	change_irq  = new_serial.irq != port->irq;
	change_port = new_port != port->uart_base;

	if (!capable(CAP_SYS_ADMIN)) {
		if (change_irq || change_port ||
		    (new_serial.baud_base != port->uartclk / 16) ||
		    (new_serial.close_delay != state->close_delay) ||
		    (new_serial.xmit_fifo_size != port->fifosize) ||
		    ((new_serial.flags & ~ASYNC_USR_MASK) !=
		     (state->flags & ~ASYNC_USR_MASK)))
			return -EPERM;
		state->flags = ((state->flags & ~ASYNC_USR_MASK) |
				(new_serial.flags & ASYNC_USR_MASK));
		info->flags = ((info->flags & ~ASYNC_USR_MASK) |
			       (new_serial.flags & ASYNC_USR_MASK));
		state->custom_divisor = new_serial.custom_divisor;
		goto check_and_exit;
	}

	if ((new_serial.irq >= NR_IRQS) || (new_serial.irq < 0) ||
	    (new_serial.baud_base < 9600))
		return -EINVAL;

	if (new_serial.type && change_port) {
		for (i = 0; i < SERIAL_AMBA_NR; i++)
			if ((port != amba_ports + i) &&
			    amba_ports[i].uart_base != new_port)
				return -EADDRINUSE;
	}

	if ((change_port || change_irq) && (state->count > 1))
		return -EBUSY;

	/*
	 * OK, past this point, all the error checking has been done.
	 * At this point, we start making changes.....
	 */
	port->uartclk = new_serial.baud_base * 16;
	state->flags = ((state->flags & ~ASYNC_FLAGS) |
			(new_serial.flags & ASYNC_FLAGS));
	info->flags = ((state->flags & ~ASYNC_INTERNAL_FLAGS) |
		       (info->flags & ASYNC_INTERNAL_FLAGS));
	state->custom_divisor = new_serial.custom_divisor;
	state->close_delay = new_serial.close_delay * HZ / 100;
	state->closing_wait = new_serial.closing_wait * HZ / 100;
	info->tty->low_latency = (info->flags & ASYNC_LOW_LATENCY) ? 1 : 0;
	port->fifosize = new_serial.xmit_fifo_size;

	if (change_port || change_irq) {
		/*
		 * We need to shutdown the serial port at the old
		 * port/irq combination.
		 */
		ambauart_shutdown(info);
		port->irq = new_serial.irq;
		port->uart_base = new_port;
	}

check_and_exit:
	if (!port->uart_base)
		return 0;
	if (info->flags & ASYNC_INITIALIZED) {
		if ((old_state.flags & ASYNC_SPD_MASK) !=
		    (state->flags & ASYNC_SPD_MASK) ||
		    (old_state.custom_divisor != state->custom_divisor)) {
			if ((state->flags & ASYNC_SPD_MASK) == ASYNC_SPD_HI)
				info->tty->alt_speed = 57600;
			if ((state->flags & ASYNC_SPD_MASK) == ASYNC_SPD_VHI)
				info->tty->alt_speed = 115200;
			if ((state->flags & ASYNC_SPD_MASK) == ASYNC_SPD_SHI)
				info->tty->alt_speed = 230400;
			if ((state->flags & ASYNC_SPD_MASK) == ASYNC_SPD_WARP)
				info->tty->alt_speed = 460800;
			ambauart_change_speed(info, NULL);
		}
	} else
		retval = ambauart_startup(info);
	return retval;
}


/*
 * get_lsr_info - get line status register info
 */
static int get_lsr_info(struct amba_info *info, unsigned int *value)
{
	unsigned int result, status;
	unsigned long flags;

	save_flags(flags); cli();
	status = UART_GET_FR(info->port);
	restore_flags(flags);
	result = status & AMBA_UARTFR_BUSY ? TIOCSER_TEMT : 0;

	/*
	 * If we're about to load something into the transmit
	 * register, we'll pretend the transmitter isn't empty to
	 * avoid a race condition (depending on when the transmit
	 * interrupt happens).
	 */
	if (info->x_char ||
	    ((CIRC_CNT(info->xmit.head, info->xmit.tail,
		       AMBA_XMIT_SIZE) > 0) &&
	     !info->tty->stopped && !info->tty->hw_stopped))
		result &= TIOCSER_TEMT;
	
	return put_user(result, value);
}

static int get_modem_info(struct amba_info *info, unsigned int *value)
{
	unsigned int result = info->mctrl;
	unsigned int status;

	status = UART_GET_FR(info->port);
	if (status & AMBA_UARTFR_DCD)
		result |= TIOCM_CAR;
	if (status & AMBA_UARTFR_DSR)
		result |= TIOCM_DSR;
	if (status & AMBA_UARTFR_CTS)
		result |= TIOCM_CTS;

	return put_user(result, value);
}

static int set_modem_info(struct amba_info *info, unsigned int cmd,
			  unsigned int *value)
{
	unsigned int arg, old;
	unsigned long flags;

	if (get_user(arg, value))
		return -EFAULT;

	old = info->mctrl;
	switch (cmd) {
	case TIOCMBIS:
		info->mctrl |= arg;
		break;

	case TIOCMBIC:
		info->mctrl &= ~arg;
		break;

	case TIOCMSET:
		info->mctrl = arg;
		break;

	default:
		return -EINVAL;
	}
	save_flags(flags); cli();
	if (old != info->mctrl)
		info->port->set_mctrl(info->port, info->mctrl);
	restore_flags(flags);
	return 0;
}

static void ambauart_break_ctl(struct tty_struct *tty, int break_state)
{
	struct amba_info *info = tty->driver_data;
	unsigned long flags;
	unsigned int lcr_h;

	save_flags(flags); cli();
	lcr_h = UART_GET_LCRH(info->port);
	if (break_state == -1)
		lcr_h |= AMBA_UARTLCR_H_BRK;
	else
		lcr_h &= ~AMBA_UARTLCR_H_BRK;
	UART_PUT_LCRH(info->port, lcr_h);
	restore_flags(flags);
}

static int ambauart_ioctl(struct tty_struct *tty, struct file *file,
			   unsigned int cmd, unsigned long arg)
{
	struct amba_info *info = tty->driver_data;
	struct amba_icount cprev, cnow;
	struct serial_icounter_struct icount;
	unsigned long flags;

	if ((cmd != TIOCGSERIAL) && (cmd != TIOCSSERIAL) &&
	    (cmd != TIOCSERCONFIG) && (cmd != TIOCSERGSTRUCT) &&
	    (cmd != TIOCMIWAIT) && (cmd != TIOCGICOUNT)) {
		if (tty->flags & (1 << TTY_IO_ERROR))
			return -EIO;
	}

	switch (cmd) {
		case TIOCMGET:
			return get_modem_info(info, (unsigned int *)arg);
		case TIOCMBIS:
		case TIOCMBIC:
		case TIOCMSET:
			return set_modem_info(info, cmd, (unsigned int *)arg);
		case TIOCGSERIAL:
			return get_serial_info(info,
					       (struct serial_struct *)arg);
		case TIOCSSERIAL:
			return set_serial_info(info,
					       (struct serial_struct *)arg);
		case TIOCSERGETLSR: /* Get line status register */
			return get_lsr_info(info, (unsigned int *)arg);
		/*
		 * Wait for any of the 4 modem inputs (DCD,RI,DSR,CTS) to change
		 * - mask passed in arg for lines of interest
		 *   (use |'ed TIOCM_RNG/DSR/CD/CTS for masking)
		 * Caller should use TIOCGICOUNT to see which one it was
		 */
		case TIOCMIWAIT:
			save_flags(flags); cli();
			/* note the counters on entry */
			cprev = info->state->icount;
			/* Force modem status interrupts on */
			UART_PUT_CR(info->port, UART_GET_CR(info->port) | AMBA_UARTCR_MSIE);
			restore_flags(flags);
			while (1) {
				interruptible_sleep_on(&info->delta_msr_wait);
				/* see if a signal did it */
				if (signal_pending(current))
					return -ERESTARTSYS;
				save_flags(flags); cli();
				cnow = info->state->icount; /* atomic copy */
				restore_flags(flags);
				if (cnow.rng == cprev.rng && cnow.dsr == cprev.dsr &&
				    cnow.dcd == cprev.dcd && cnow.cts == cprev.cts)
					return -EIO; /* no change => error */
				if (((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
				    ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
				    ((arg & TIOCM_CD)  && (cnow.dcd != cprev.dcd)) ||
				    ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts))) {
					return 0;
				}
				cprev = cnow;
			}
			/* NOTREACHED */

		/*
		 * Get counter of input serial line interrupts (DCD,RI,DSR,CTS)
		 * Return: write counters to the user passed counter struct
		 * NB: both 1->0 and 0->1 transitions are counted except for
		 *     RI where only 0->1 is counted.
		 */
		case TIOCGICOUNT:
			save_flags(flags); cli();
			cnow = info->state->icount;
			restore_flags(flags);
			icount.cts = cnow.cts;
			icount.dsr = cnow.dsr;
			icount.rng = cnow.rng;
			icount.dcd = cnow.dcd;
			icount.rx  = cnow.rx;
			icount.tx  = cnow.tx;
			icount.frame = cnow.frame;
			icount.overrun = cnow.overrun;
			icount.parity = cnow.parity;
			icount.brk = cnow.brk;
			icount.buf_overrun = cnow.buf_overrun;

			return copy_to_user((void *)arg, &icount, sizeof(icount))
					? -EFAULT : 0;

		default:
			return -ENOIOCTLCMD;
	}
	return 0;
}

static void ambauart_set_termios(struct tty_struct *tty, struct termios *old_termios)
{
	struct amba_info *info = tty->driver_data;
	unsigned long flags;
	unsigned int cflag = tty->termios->c_cflag;

	if ((cflag ^ old_termios->c_cflag) == 0 &&
	    RELEVENT_IFLAG(tty->termios->c_iflag ^ old_termios->c_iflag) == 0)
		return;

	ambauart_change_speed(info, old_termios);

	/* Handle transition to B0 status */
	if ((old_termios->c_cflag & CBAUD) &&
	    !(cflag & CBAUD)) {
		save_flags(flags); cli();
		info->mctrl &= ~(TIOCM_RTS | TIOCM_DTR);
		info->port->set_mctrl(info->port, info->mctrl);
		restore_flags(flags);
	}

	/* Handle transition away from B0 status */
	if (!(old_termios->c_cflag & CBAUD) &&
	    (cflag & CBAUD)) {
		save_flags(flags); cli();
		info->mctrl |= TIOCM_DTR;
		if (!(cflag & CRTSCTS) ||
		    !test_bit(TTY_THROTTLED, &tty->flags))
			info->mctrl |= TIOCM_RTS;
		info->port->set_mctrl(info->port, info->mctrl);
		restore_flags(flags);
	}

	/* Handle turning off CRTSCTS */
	if ((old_termios->c_cflag & CRTSCTS) &&
	    !(cflag & CRTSCTS)) {
		tty->hw_stopped = 0;
		ambauart_start(tty);
	}

#if 0
	/*
	 * No need to wake up processes in open wait, since they
	 * sample the CLOCAL flag once, and don't recheck it.
	 * XXX  It's not clear whether the current behavior is correct
	 * or not.  Hence, this may change.....
	 */
	if (!(old_termios->c_cflag & CLOCAL) &&
	    (tty->termios->c_cflag & CLOCAL))
		wake_up_interruptible(&info->open_wait);
#endif
}

static void ambauart_close(struct tty_struct *tty, struct file *filp)
{
	struct amba_info *info = tty->driver_data;
	struct amba_state *state;
	unsigned long flags;

	if (!info)
		return;

	state = info->state;

#if DEBUG
	printk("ambauart_close() called\n");
#endif

	save_flags(flags); cli();

	if (tty_hung_up_p(filp)) {
		MOD_DEC_USE_COUNT;
		restore_flags(flags);
		return;
	}

	if ((tty->count == 1) && (state->count != 1)) {
		/*
		 * Uh, oh.  tty->count is 1, which means that the tty
		 * structure will be freed.  state->count should always
		 * be one in these conditions.  If it's greater than
		 * one, we've got real problems, since it means the
		 * serial port won't be shutdown.
		 */
		printk("ambauart_close: bad serial port count; tty->count is 1, "
		       "state->count is %d\n", state->count);
		state->count = 1;
	}
	if (--state->count < 0) {
		printk("rs_close: bad serial port count for %s%d: %d\n",
		       tty->driver.name, info->state->line, state->count);
		state->count = 0;
	}
	if (state->count) {
		MOD_DEC_USE_COUNT;
		restore_flags(flags);
		return;
	}
	info->flags |= ASYNC_CLOSING;
	restore_flags(flags);
	/*
	 * Save the termios structure, since this port may have
	 * separate termios for callout and dialin.
	 */
	if (info->flags & ASYNC_NORMAL_ACTIVE)
		info->state->normal_termios = *tty->termios;
	if (info->flags & ASYNC_CALLOUT_ACTIVE)
		info->state->callout_termios = *tty->termios;
	/*
	 * Now we wait for the transmit buffer to clear; and we notify
	 * the line discipline to only process XON/XOFF characters.
	 */
	tty->closing = 1;
	if (info->state->closing_wait != ASYNC_CLOSING_WAIT_NONE)
		tty_wait_until_sent(tty, info->state->closing_wait);
	/*
	 * At this point, we stop accepting input.  To do this, we
	 * disable the receive line status interrupts.
	 */
	if (info->flags & ASYNC_INITIALIZED) {
		ambauart_disable_rx_interrupt(info);
		/*
		 * Before we drop DTR, make sure the UART transmitter
		 * has completely drained; this is especially
		 * important if there is a transmit FIFO!
		 */
		ambauart_wait_until_sent(tty, info->timeout);
	}
	ambauart_shutdown(info);
	if (tty->driver.flush_buffer)
		tty->driver.flush_buffer(tty);
	if (tty->ldisc.flush_buffer)
		tty->ldisc.flush_buffer(tty);
	tty->closing = 0;
	info->event = 0;
	info->tty = NULL;
	if (info->blocked_open) {
		if (info->state->close_delay) {
			set_current_state(TASK_INTERRUPTIBLE);
			schedule_timeout(info->state->close_delay);
		}
		wake_up_interruptible(&info->open_wait);
	}
	info->flags &= ~(ASYNC_NORMAL_ACTIVE|ASYNC_CALLOUT_ACTIVE|
			 ASYNC_CLOSING);
	wake_up_interruptible(&info->close_wait);
	MOD_DEC_USE_COUNT;
}

static void ambauart_wait_until_sent(struct tty_struct *tty, int timeout)
{
	struct amba_info *info = (struct amba_info *) tty->driver_data;
	unsigned long char_time, expire;
	unsigned int status;

	if (info->port->fifosize == 0)
		return;