duart_serial.c

powerpc内核mpc8241linux系统下char驱动程序

	info->IER |= UART_IER_THRI;
	serial_out(info, UART_IER, info->IER);
	restore_flags(flags);
}

static int rs_write(struct tty_struct * tty, int from_user,
		    const unsigned char *buf, int count)
{
	int	c, ret = 0;
	struct async_struct *info = (struct async_struct *)tty->driver_data;
	unsigned long flags;
				
	if (serial_paranoia_check(info, tty->device, "rs_write"))
		return 0;

	if (!tty || !info->xmit_buf || !tmp_buf)
		return 0;

	save_flags(flags);
	if (from_user) {
		down(&tmp_buf_sem);
		while (1) {
			c = MIN(count,
				MIN(SERIAL_XMIT_SIZE - info->xmit_cnt - 1,
				    SERIAL_XMIT_SIZE - info->xmit_head));
			if (c <= 0)
				break;

			c -= copy_from_user(tmp_buf, buf, c);
			if (!c) {
				if (!ret)
					ret = -EFAULT;
				break;
			}
			cli();
			c = MIN(c, MIN(SERIAL_XMIT_SIZE - info->xmit_cnt - 1,
				       SERIAL_XMIT_SIZE - info->xmit_head));
			memcpy(info->xmit_buf + info->xmit_head, tmp_buf, c);
			info->xmit_head = ((info->xmit_head + c) &
					   (SERIAL_XMIT_SIZE-1));
			info->xmit_cnt += c;
			restore_flags(flags);
			buf += c;
			count -= c;
			ret += c;
		}
		up(&tmp_buf_sem);
	} else {
		while (1) {
			cli();		
			c = MIN(count,
				MIN(SERIAL_XMIT_SIZE - info->xmit_cnt - 1,
				    SERIAL_XMIT_SIZE - info->xmit_head));
			if (c <= 0) {
				restore_flags(flags);
				break;
			}
			memcpy(info->xmit_buf + info->xmit_head, buf, c);
			info->xmit_head = ((info->xmit_head + c) &
					   (SERIAL_XMIT_SIZE-1));
			info->xmit_cnt += c;
			restore_flags(flags);
			buf += c;
			count -= c;
			ret += c;
		}
	}
	if (info->xmit_cnt && !tty->stopped && !tty->hw_stopped &&
	    !(info->IER & UART_IER_THRI)) {
		info->IER |= UART_IER_THRI;
		serial_out(info, UART_IER, info->IER);

	}

	return ret;
}

static int rs_write_room(struct tty_struct *tty)
{
	struct async_struct *info = (struct async_struct *)tty->driver_data;
	int	ret;
				
	if (serial_paranoia_check(info, tty->device, "rs_write_room"))
		return 0;
	ret = SERIAL_XMIT_SIZE - info->xmit_cnt - 1;
	if (ret < 0)
		ret = 0;
	return ret;
}

static int rs_chars_in_buffer(struct tty_struct *tty)
{
	struct async_struct *info = (struct async_struct *)tty->driver_data;
				
	if (serial_paranoia_check(info, tty->device, "rs_chars_in_buffer"))
		return 0;
	return info->xmit_cnt;
}

static void rs_flush_buffer(struct tty_struct *tty)
{
	struct async_struct *info = (struct async_struct *)tty->driver_data;
	unsigned long flags;
	
	if (serial_paranoia_check(info, tty->device, "rs_flush_buffer"))
		return;
	save_flags(flags); cli();
	info->xmit_cnt = info->xmit_head = info->xmit_tail = 0;
	restore_flags(flags);
	wake_up_interruptible(&tty->write_wait);
	if ((tty->flags & (1 << TTY_DO_WRITE_WAKEUP)) &&
	    tty->ldisc.write_wakeup)
		(tty->ldisc.write_wakeup)(tty);
}

/*
 * This function is used to send a high-priority XON/XOFF character to
 * the device
 */
static void rs_send_xchar(struct tty_struct *tty, char ch)
{
	struct async_struct *info = (struct async_struct *)tty->driver_data;

	if (serial_paranoia_check(info, tty->device, "rs_send_char"))
		return;

	info->x_char = ch;
	if (ch) {
		/* Make sure transmit interrupts are on */
		info->IER |= UART_IER_THRI;
		serial_out(info, UART_IER, info->IER);
	}
}

/*
 * ------------------------------------------------------------
 * rs_throttle()
 * 
 * This routine is called by the upper-layer tty layer to signal that
 * incoming characters should be throttled.
 * ------------------------------------------------------------
 */
static void rs_throttle(struct tty_struct * tty)
{
	struct async_struct *info = (struct async_struct *)tty->driver_data;
	unsigned long flags;
#ifdef SERIAL_DEBUG_THROTTLE
	char	buf[64];
	
	printk("throttle %s: %d....\n", tty_name(tty, buf),
	       tty->ldisc.chars_in_buffer(tty));
#endif

	if (serial_paranoia_check(info, tty->device, "rs_throttle"))
		return;
	
	if (I_IXOFF(tty))
		rs_send_xchar(tty, STOP_CHAR(tty));

	if (tty->termios->c_cflag & CRTSCTS)
		info->MCR &= ~UART_MCR_RTS;

	save_flags(flags); cli();
	serial_out(info, UART_MCR, info->MCR);
	restore_flags(flags);
}

static void rs_unthrottle(struct tty_struct * tty)
{
	struct async_struct *info = (struct async_struct *)tty->driver_data;
	unsigned long flags;
#ifdef SERIAL_DEBUG_THROTTLE
	char	buf[64];
	
	printk("unthrottle %s: %d....\n", tty_name(tty, buf),
	       tty->ldisc.chars_in_buffer(tty));
#endif

	if (serial_paranoia_check(info, tty->device, "rs_unthrottle"))
		return;
	
	if (I_IXOFF(tty)) {
		if (info->x_char)
			info->x_char = 0;
		else
			rs_send_xchar(tty, START_CHAR(tty));
	}
	if (tty->termios->c_cflag & CRTSCTS)
		info->MCR |= UART_MCR_RTS;
	save_flags(flags); cli();
	serial_out(info, UART_MCR, info->MCR);
	restore_flags(flags);
}

/*
 * ------------------------------------------------------------
 * rs_ioctl() and friends
 * ------------------------------------------------------------
 */

static int get_serial_info(struct async_struct * info,
			   struct serial_struct * retinfo)
{
	struct serial_struct tmp;
	struct serial_state *state = info->state;
   
	if (!retinfo)
		return -EFAULT;
	memset(&tmp, 0, sizeof(tmp));
	tmp.type = state->type;
	tmp.line = state->line;
	tmp.port = state->port;
	tmp.irq = state->irq;
	tmp.flags = state->flags;
	tmp.xmit_fifo_size = state->xmit_fifo_size;
	tmp.baud_base = state->baud_base;
	tmp.close_delay = state->close_delay;
	tmp.closing_wait = state->closing_wait;
	tmp.custom_divisor = state->custom_divisor;
	tmp.hub6 = state->hub6;
	if (copy_to_user(retinfo,&tmp,sizeof(*retinfo)))
		return -EFAULT;
	return 0;
}

static int set_serial_info(struct async_struct * info,
			   struct serial_struct * new_info)
{
	struct serial_struct new_serial;
 	struct serial_state old_state, *state;
	unsigned int		i,change_irq,change_port;
	int 			retval = 0;

	if (copy_from_user(&new_serial,new_info,sizeof(new_serial)))
		return -EFAULT;
	state = info->state;
	old_state = *state;
  
	change_irq = new_serial.irq != state->irq;
	change_port = (new_serial.port != state->port) ||
		(new_serial.hub6 != state->hub6);
  
	if (!capable(CAP_SYS_ADMIN)) {
		if (change_irq || change_port ||
		    (new_serial.baud_base != state->baud_base) ||
		    (new_serial.type != state->type) ||
		    (new_serial.close_delay != state->close_delay) ||
		    (new_serial.xmit_fifo_size != state->xmit_fifo_size) ||
		    ((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;
	}

	new_serial.irq = irq_cannonicalize(new_serial.irq);

	if ((new_serial.irq >= NR_IRQS) || (new_serial.port > 0xffff) ||
	    (new_serial.baud_base < 9600)|| (new_serial.type < PORT_UNKNOWN) ||
	    (new_serial.type > PORT_MAX) || (new_serial.type == PORT_CIRRUS) ||
	    (new_serial.type == PORT_STARTECH)) {
		return -EINVAL;
	}

	if ((new_serial.type != state->type) ||
	    (new_serial.xmit_fifo_size <= 0))
		new_serial.xmit_fifo_size =
			uart_config[state->type].dfl_xmit_fifo_size;

	/* Make sure address is not already in use */
	if (new_serial.type) {
		for (i = 0 ; i < NR_PORTS; i++)
			if ((state != &rs_table[i]) &&
			    (rs_table[i].port == new_serial.port) &&
			    rs_table[i].type)
				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.....
	 */

	state->baud_base = new_serial.baud_base;
	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->type = new_serial.type;
	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;
	info->xmit_fifo_size = state->xmit_fifo_size =
		new_serial.xmit_fifo_size;

	release_region(state->port,8);
	if (change_port || change_irq) {
		/*
		 * We need to shutdown the serial port at the old
		 * port/irq combination.
		 */
		shutdown(info);
		state->irq = new_serial.irq;
		info->port = state->port = new_serial.port;
		info->hub6 = state->hub6 = new_serial.hub6;
	}
	if (state->type != PORT_UNKNOWN)
		request_region(state->port,8,"serial(set)");

	
check_and_exit:
	if (!state->port || !state->type)
		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;
			change_speed(info, 0);
		}
	} else
		retval = startup(info);
	return retval;
}


/*
 * get_lsr_info - get line status register info
 *
 * Purpose: Let user call ioctl() to get info when the UART physically
 * 	    is emptied.  On bus types like RS485, the transmitter must
 * 	    release the bus after transmitting. This must be done when
 * 	    the transmit shift register is empty, not be done when the
 * 	    transmit holding register is empty.  This functionality
 * 	    allows an RS485 driver to be written in user space. 
 */
static int get_lsr_info(struct async_struct * info, unsigned int *value)
{
	unsigned char status;
	unsigned int result;
	unsigned long flags;

	save_flags(flags); cli();
	status = serial_in(info, UART_LSR);
	restore_flags(flags);
	result = ((status & UART_LSR_TEMT) ? TIOCSER_TEMT : 0);
	return put_user(result,value);
}


static int get_modem_info(struct async_struct * info, unsigned int *value)
{
	unsigned char control, status;
	unsigned int result;
	unsigned long flags;

	control = info->MCR;
	save_flags(flags); cli();
	status = serial_in(info, UART_MSR);
	restore_flags(flags);
	result =  ((control & UART_MCR_RTS) ? TIOCM_RTS : 0)
		| ((control & UART_MCR_DTR) ? TIOCM_DTR : 0)
#ifdef TIOCM_OUT1
		| ((control & UART_MCR_OUT1) ? TIOCM_OUT1 : 0)
		| ((control & UART_MCR_OUT2) ? TIOCM_OUT2 : 0)
#endif
		| ((status  & UART_MSR_DCD) ? TIOCM_CAR : 0)
		| ((status  & UART_MSR_RI) ? TIOCM_RNG : 0)
		| ((status  & UART_MSR_DSR) ? TIOCM_DSR : 0)
		| ((status  & UART_MSR_CTS) ? TIOCM_CTS : 0);
	return put_user(result,value);
}

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

	error = get_user(arg, value);
	if (error)
		return error;
	switch (cmd) {
	case TIOCMBIS: 
		if (arg & TIOCM_RTS)
			info->MCR |= UART_MCR_RTS;
		if (arg & TIOCM_DTR)
			info->MCR |= UART_MCR_DTR;
#ifdef TIOCM_OUT1
		if (arg & TIOCM_OUT1)
			info->MCR |= UART_MCR_OUT1;
		if (arg & TIOCM_OUT2)
			info->MCR |= UART_MCR_OUT2;
#endif
		break;
	case TIOCMBIC:
		if (arg & TIOCM_RTS)
			info->MCR &= ~UART_MCR_RTS;
		if (arg & TIOCM_DTR)
			info->MCR &= ~UART_MCR_DTR;
#ifdef TIOCM_OUT1
		if (arg & TIOCM_OUT1)
			info->MCR &= ~UART_MCR_OUT1;
		if (arg & TIOCM_OUT2)
			info->MCR &= ~UART_MCR_OUT2;
#endif
		break;
	case TIOCMSET:
		info->MCR = ((info->MCR & ~(UART_MCR_RTS |
#ifdef TIOCM_OUT1
					    UART_MCR_OUT1 |
					    UART_MCR_OUT2 |
#endif
					    UART_MCR_DTR))
			     | ((arg & TIOCM_RTS) ? UART_MCR_RTS : 0)
#ifdef TIOCM_OUT1
			     | ((arg & TIOCM_OUT1) ? UART_MCR_OUT1 : 0)
			     | ((arg & TIOCM_OUT2) ? UART_MCR_OUT2 : 0)
#endif
			     | ((arg & TIOCM_DTR) ? UART_MCR_DTR : 0));
		break;
	default:
		return -EINVAL;
	}
	save_flags(flags); cli();
	serial_out(info, UART_MCR, info->MCR);
	restore_flags(flags);
	return 0;
}

static int do_autoconfig(struct async_struct * info)
{
	int			retval;
	
	if (!capable(CAP_SYS_ADMIN))
		return -EPERM;
	
	if (info->state->count > 1)
		return -EBUSY;
	
	shutdown(info);

	autoconfig(info->state);
	if ((info->state->flags & ASYNC_AUTO_IRQ) &&
	    (info->state->port != 0) &&
	    (info->state->type != PORT_UNKNOWN))
		info->state->irq = detect_uart_irq(info->state);

	retval = startup(info);
	if (retval)
		return retval;
	return 0;
}

/*
 * rs_break() --- routine which turns the break handling on or off
 */
static void rs_break(struct tty_struct *tty, int break_state)
{
	struct async_struct * info = (struct async_struct *)tty->driver_data;
	unsigned long flags;
	
	if (serial_paranoia_check(info, tty->device, "rs_break"))
		return;

	if (!info->port)
		return;
	save_flags(flags); cli();
	if (break_state == -1)
		serial_out(info, UART_LCR,
			   serial_inp(info, UART_LCR) | UART_LCR_SBC);
	else
		serial_out(info, UART_LCR,
			   serial_inp(info, UART_LCR) & ~UART_LCR_SBC);
	restore_flags(flags);
}

#ifdef CONFIG_SERIAL_MULTIPORT
static int get_multiport_struct(struct async_struct * info,