path: root/drivers/s390/net/ctctty.c

/*
 * $Id: ctctty.c,v 1.29 2005/04/05 08:50:44 mschwide Exp $
 *
 * CTC / ESCON network driver, tty interface.
 *
 * Copyright (C) 2001 IBM Deutschland Entwicklung GmbH, IBM Corporation
 * Author(s): Fritz Elfert (elfert@de.ibm.com, felfert@millenux.com)
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */

#include <linux/config.h>
#include <linux/module.h>
#include <linux/tty.h>
#include <linux/serial_reg.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <asm/uaccess.h>
#include <linux/devfs_fs_kernel.h>
#include "ctctty.h"
#include "ctcdbug.h"

#define CTC_TTY_MAJOR       43
#define CTC_TTY_MAX_DEVICES 64

#define CTC_ASYNC_MAGIC          0x49344C01 /* for paranoia-checking        */
#define CTC_ASYNC_INITIALIZED    0x80000000 /* port was initialized         */
#define CTC_ASYNC_NORMAL_ACTIVE  0x20000000 /* Normal device active         */
#define CTC_ASYNC_CLOSING        0x08000000 /* Serial port is closing       */
#define CTC_ASYNC_CTS_FLOW       0x04000000 /* Do CTS flow control          */
#define CTC_ASYNC_CHECK_CD       0x02000000 /* i.e., CLOCAL                 */
#define CTC_ASYNC_HUP_NOTIFY         0x0001 /* Notify tty on hangups/closes */
#define CTC_ASYNC_NETDEV_OPEN        0x0002 /* Underlying netdev is open    */
#define CTC_ASYNC_TX_LINESTAT        0x0004 /* Must send line status        */
#define CTC_ASYNC_SPLIT_TERMIOS      0x0008 /* Sep. termios for dialin/out  */
#define CTC_TTY_XMIT_SIZE              1024 /* Default bufsize for write    */
#define CTC_SERIAL_XMIT_MAX            4000 /* Maximum bufsize for write    */

/* Private data (similar to async_struct in <linux/serial.h>) */
typedef struct {
  int			magic;
  int			flags;		 /* defined in tty.h               */
  int			mcr;		 /* Modem control register         */
  int                   msr;             /* Modem status register          */
  int                   lsr;             /* Line status register           */
  int			line;
  int			count;		 /* # of fd on device              */
  int			blocked_open;	 /* # of blocked opens             */
  struct net_device     *netdev;
  struct sk_buff_head   tx_queue;        /* transmit queue                 */
  struct sk_buff_head   rx_queue;        /* receive queue                  */
  struct tty_struct 	*tty;            /* Pointer to corresponding tty   */
  wait_queue_head_t	open_wait;
  wait_queue_head_t	close_wait;
  struct semaphore      write_sem;
  struct tasklet_struct tasklet;
  struct timer_list     stoptimer;
} ctc_tty_info;

/* Description of one CTC-tty */
typedef struct {
  struct tty_driver  *ctc_tty_device;		   /* tty-device             */
  ctc_tty_info       info[CTC_TTY_MAX_DEVICES];	   /* Private data           */
} ctc_tty_driver;

static ctc_tty_driver *driver;

/* Leave this unchanged unless you know what you do! */
#define MODEM_PARANOIA_CHECK
#define MODEM_DO_RESTART

#define CTC_TTY_NAME "ctctty"

static __u32 ctc_tty_magic = CTC_ASYNC_MAGIC;
static int ctc_tty_shuttingdown = 0;

static spinlock_t ctc_tty_lock;

/* ctc_tty_try_read() is called from within ctc_tty_rcv_skb()
 * to stuff incoming data directly into a tty's flip-buffer. If the
 * flip buffer is full, the packet gets queued up.
 *
 * Return:
 *  1 = Success
 *  0 = Failure, data has to be buffered and later processed by
 *      ctc_tty_readmodem().
 */
static int
ctc_tty_try_read(ctc_tty_info * info, struct sk_buff *skb)
{
	int c;
	int len;
	struct tty_struct *tty;

	DBF_TEXT(trace, 5, __FUNCTION__);
	if ((tty = info->tty)) {
		if (info->mcr & UART_MCR_RTS) {
			c = TTY_FLIPBUF_SIZE -