Logo Search packages:      
Sourcecode: linux version File versions  Download package

n_r3964.c

/* r3964 linediscipline for linux
 *
 * -----------------------------------------------------------
 * Copyright by 
 * Philips Automation Projects
 * Kassel (Germany)
 * http://www.pap-philips.de
 * -----------------------------------------------------------
 * This software may be used and distributed according to the terms of
 * the GNU General Public License, incorporated herein by reference.
 *
 * Author:
 * L. Haag
 *
 * $Log: n_r3964.c,v $
 * Revision 1.10  2001/03/18 13:02:24  dwmw2
 * Fix timer usage, use spinlocks properly.
 *
 * Revision 1.9  2001/03/18 12:52:14  dwmw2
 * Merge changes in 2.4.2
 *
 * Revision 1.8  2000/03/23 14:14:54  dwmw2
 * Fix race in sleeping in r3964_read()
 *
 * Revision 1.7  1999/28/08 11:41:50  dwmw2
 * Port to 2.3 kernel
 *
 * Revision 1.6  1998/09/30 00:40:40  dwmw2
 * Fixed compilation on 2.0.x kernels
 * Updated to newly registered tty-ldisc number 9
 *
 * Revision 1.5  1998/09/04 21:57:36  dwmw2
 * Signal handling bug fixes, port to 2.1.x.
 *
 * Revision 1.4  1998/04/02 20:26:59  lhaag
 * select, blocking, ...
 *
 * Revision 1.3  1998/02/12 18:58:43  root
 * fixed some memory leaks
 * calculation of checksum characters
 *
 * Revision 1.2  1998/02/07 13:03:34  root
 * ioctl read_telegram
 *
 * Revision 1.1  1998/02/06 19:21:03  root
 * Initial revision
 *
 *
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/interrupt.h>
#include <linux/ptrace.h>
#include <linux/ioport.h>
#include <linux/in.h>
#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/errno.h>
#include <linux/string.h>     /* used in new tty drivers */
#include <linux/signal.h>     /* used in new tty drivers */
#include <linux/ioctl.h>
#include <linux/n_r3964.h>
#include <linux/poll.h>
#include <linux/init.h>
#include <asm/uaccess.h>

/*#define DEBUG_QUEUE*/

/* Log successful handshake and protocol operations  */
/*#define DEBUG_PROTO_S*/

/* Log handshake and protocol errors: */
/*#define DEBUG_PROTO_E*/

/* Log Linediscipline operations (open, close, read, write...): */
/*#define DEBUG_LDISC*/

/* Log module and memory operations (init, cleanup; kmalloc, kfree): */
/*#define DEBUG_MODUL*/

/* Macro helpers for debug output: */
#define TRACE(format, args...) printk("r3964: " format "\n" , ## args)

#ifdef DEBUG_MODUL
#define TRACE_M(format, args...) printk("r3964: " format "\n" , ## args)
#else
#define TRACE_M(fmt, arg...) do {} while (0)
#endif
#ifdef DEBUG_PROTO_S
#define TRACE_PS(format, args...) printk("r3964: " format "\n" , ## args)
#else
#define TRACE_PS(fmt, arg...) do {} while (0)
#endif
#ifdef DEBUG_PROTO_E
#define TRACE_PE(format, args...) printk("r3964: " format "\n" , ## args)
#else
#define TRACE_PE(fmt, arg...) do {} while (0)
#endif
#ifdef DEBUG_LDISC
#define TRACE_L(format, args...) printk("r3964: " format "\n" , ## args)
#else
#define TRACE_L(fmt, arg...) do {} while (0)
#endif
#ifdef DEBUG_QUEUE
#define TRACE_Q(format, args...) printk("r3964: " format "\n" , ## args)
#else
#define TRACE_Q(fmt, arg...) do {} while (0)
#endif
static void add_tx_queue(struct r3964_info *, struct r3964_block_header *);
static void remove_from_tx_queue(struct r3964_info *pInfo, int error_code);
static void put_char(struct r3964_info *pInfo, unsigned char ch);
static void trigger_transmit(struct r3964_info *pInfo);
static void retry_transmit(struct r3964_info *pInfo);
static void transmit_block(struct r3964_info *pInfo);
static void receive_char(struct r3964_info *pInfo, const unsigned char c);
static void receive_error(struct r3964_info *pInfo, const char flag);
static void on_timeout(unsigned long priv);
static int enable_signals(struct r3964_info *pInfo, struct pid *pid, int arg);
static int read_telegram(struct r3964_info *pInfo, struct pid *pid,
            unsigned char __user * buf);
static void add_msg(struct r3964_client_info *pClient, int msg_id, int arg,
            int error_code, struct r3964_block_header *pBlock);
static struct r3964_message *remove_msg(struct r3964_info *pInfo,
            struct r3964_client_info *pClient);
static void remove_client_block(struct r3964_info *pInfo,
            struct r3964_client_info *pClient);

static int r3964_open(struct tty_struct *tty);
static void r3964_close(struct tty_struct *tty);
static ssize_t r3964_read(struct tty_struct *tty, struct file *file,
            unsigned char __user * buf, size_t nr);
static ssize_t r3964_write(struct tty_struct *tty, struct file *file,
            const unsigned char *buf, size_t nr);
static int r3964_ioctl(struct tty_struct *tty, struct file *file,
            unsigned int cmd, unsigned long arg);
static void r3964_set_termios(struct tty_struct *tty, struct ktermios *old);
static unsigned int r3964_poll(struct tty_struct *tty, struct file *file,
            struct poll_table_struct *wait);
static void r3964_receive_buf(struct tty_struct *tty, const unsigned char *cp,
            char *fp, int count);

static struct tty_ldisc tty_ldisc_N_R3964 = {
      .owner = THIS_MODULE,
      .magic = TTY_LDISC_MAGIC,
      .name = "R3964",
      .open = r3964_open,
      .close = r3964_close,
      .read = r3964_read,
      .write = r3964_write,
      .ioctl = r3964_ioctl,
      .set_termios = r3964_set_termios,
      .poll = r3964_poll,
      .receive_buf = r3964_receive_buf,
};

static void dump_block(const unsigned char *block, unsigned int length)
{
      unsigned int i, j;
      char linebuf[16 * 3 + 1];

      for (i = 0; i < length; i += 16) {
            for (j = 0; (j < 16) && (j + i < length); j++) {
                  sprintf(linebuf + 3 * j, "%02x ", block[i + j]);
            }
            linebuf[3 * j] = '\0';
            TRACE_PS("%s", linebuf);
      }
}

/*************************************************************
 * Driver initialisation
 *************************************************************/

/*************************************************************
 * Module support routines
 *************************************************************/

static void __exit r3964_exit(void)
{
      int status;

      TRACE_M("cleanup_module()");

      status = tty_unregister_ldisc(N_R3964);

      if (status != 0) {
            printk(KERN_ERR "r3964: error unregistering linediscipline: "
                        "%d\n", status);
      } else {
            TRACE_L("linediscipline successfully unregistered");
      }
}

static int __init r3964_init(void)
{
      int status;

      printk("r3964: Philips r3964 Driver $Revision: 1.10 $\n");

      /*
       * Register the tty line discipline
       */

      status = tty_register_ldisc(N_R3964, &tty_ldisc_N_R3964);
      if (status == 0) {
            TRACE_L("line discipline %d registered", N_R3964);
            TRACE_L("flags=%x num=%x", tty_ldisc_N_R3964.flags,
                  tty_ldisc_N_R3964.num);
            TRACE_L("open=%p", tty_ldisc_N_R3964.open);
            TRACE_L("tty_ldisc_N_R3964 = %p", &tty_ldisc_N_R3964);
      } else {
            printk(KERN_ERR "r3964: error registering line discipline: "
                        "%d\n", status);
      }
      return status;
}

module_init(r3964_init);
module_exit(r3964_exit);

/*************************************************************
 * Protocol implementation routines
 *************************************************************/

static void add_tx_queue(struct r3964_info *pInfo,
                   struct r3964_block_header *pHeader)
{
      unsigned long flags;

      spin_lock_irqsave(&pInfo->lock, flags);

      pHeader->next = NULL;

      if (pInfo->tx_last == NULL) {
            pInfo->tx_first = pInfo->tx_last = pHeader;
      } else {
            pInfo->tx_last->next = pHeader;
            pInfo->tx_last = pHeader;
      }

      spin_unlock_irqrestore(&pInfo->lock, flags);

      TRACE_Q("add_tx_queue %p, length %d, tx_first = %p",
            pHeader, pHeader->length, pInfo->tx_first);
}

static void remove_from_tx_queue(struct r3964_info *pInfo, int error_code)
{
      struct r3964_block_header *pHeader;
      unsigned long flags;
#ifdef DEBUG_QUEUE
      struct r3964_block_header *pDump;
#endif

      pHeader = pInfo->tx_first;

      if (pHeader == NULL)
            return;

#ifdef DEBUG_QUEUE
      printk("r3964: remove_from_tx_queue: %p, length %u - ",
            pHeader, pHeader->length);
      for (pDump = pHeader; pDump; pDump = pDump->next)
            printk("%p ", pDump);
      printk("\n");
#endif

      if (pHeader->owner) {
            if (error_code) {
                  add_msg(pHeader->owner, R3964_MSG_ACK, 0,
                        error_code, NULL);
            } else {
                  add_msg(pHeader->owner, R3964_MSG_ACK, pHeader->length,
                        error_code, NULL);
            }
            wake_up_interruptible(&pInfo->read_wait);
      }

      spin_lock_irqsave(&pInfo->lock, flags);

      pInfo->tx_first = pHeader->next;
      if (pInfo->tx_first == NULL) {
            pInfo->tx_last = NULL;
      }

      spin_unlock_irqrestore(&pInfo->lock, flags);

      kfree(pHeader);
      TRACE_M("remove_from_tx_queue - kfree %p", pHeader);

      TRACE_Q("remove_from_tx_queue: tx_first = %p, tx_last = %p",
            pInfo->tx_first, pInfo->tx_last);
}

static void add_rx_queue(struct r3964_info *pInfo,
                   struct r3964_block_header *pHeader)
{
      unsigned long flags;

      spin_lock_irqsave(&pInfo->lock, flags);

      pHeader->next = NULL;

      if (pInfo->rx_last == NULL) {
            pInfo->rx_first = pInfo->rx_last = pHeader;
      } else {
            pInfo->rx_last->next = pHeader;
            pInfo->rx_last = pHeader;
      }
      pInfo->blocks_in_rx_queue++;

      spin_unlock_irqrestore(&pInfo->lock, flags);

      TRACE_Q("add_rx_queue: %p, length = %d, rx_first = %p, count = %d",
            pHeader, pHeader->length,
            pInfo->rx_first, pInfo->blocks_in_rx_queue);
}

static void remove_from_rx_queue(struct r3964_info *pInfo,
                         struct r3964_block_header *pHeader)
{
      unsigned long flags;
      struct r3964_block_header *pFind;

      if (pHeader == NULL)
            return;

      TRACE_Q("remove_from_rx_queue: rx_first = %p, rx_last = %p, count = %d",
            pInfo->rx_first, pInfo->rx_last, pInfo->blocks_in_rx_queue);
      TRACE_Q("remove_from_rx_queue: %p, length %u",
            pHeader, pHeader->length);

      spin_lock_irqsave(&pInfo->lock, flags);

      if (pInfo->rx_first == pHeader) {
            /* Remove the first block in the linked list: */
            pInfo->rx_first = pHeader->next;

            if (pInfo->rx_first == NULL) {
                  pInfo->rx_last = NULL;
            }
            pInfo->blocks_in_rx_queue--;
      } else {
            /* Find block to remove: */
            for (pFind = pInfo->rx_first; pFind; pFind = pFind->next) {
                  if (pFind->next == pHeader) {
                        /* Got it. */
                        pFind->next = pHeader->next;
                        pInfo->blocks_in_rx_queue--;
                        if (pFind->next == NULL) {
                              /* Oh, removed the last one! */
                              pInfo->rx_last = pFind;
                        }
                        break;
                  }
            }
      }

      spin_unlock_irqrestore(&pInfo->lock, flags);

      kfree(pHeader);
      TRACE_M("remove_from_rx_queue - kfree %p", pHeader);

      TRACE_Q("remove_from_rx_queue: rx_first = %p, rx_last = %p, count = %d",
            pInfo->rx_first, pInfo->rx_last, pInfo->blocks_in_rx_queue);
}

static void put_char(struct r3964_info *pInfo, unsigned char ch)
{
      struct tty_struct *tty = pInfo->tty;

      if (tty == NULL)
            return;

      if (tty->driver->put_char) {
            tty->driver->put_char(tty, ch);
      }
      pInfo->bcc ^= ch;
}

static void flush(struct r3964_info *pInfo)
{
      struct tty_struct *tty = pInfo->tty;

      if (tty == NULL)
            return;

      if (tty->driver->flush_chars) {
            tty->driver->flush_chars(tty);
      }
}

static void trigger_transmit(struct r3964_info *pInfo)
{
      unsigned long flags;

      spin_lock_irqsave(&pInfo->lock, flags);

      if ((pInfo->state == R3964_IDLE) && (pInfo->tx_first != NULL)) {
            pInfo->state = R3964_TX_REQUEST;
            pInfo->nRetry = 0;
            pInfo->flags &= ~R3964_ERROR;
            mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);

            spin_unlock_irqrestore(&pInfo->lock, flags);

            TRACE_PS("trigger_transmit - sent STX");

            put_char(pInfo, STX);
            flush(pInfo);

            pInfo->bcc = 0;
      } else {
            spin_unlock_irqrestore(&pInfo->lock, flags);
      }
}

static void retry_transmit(struct r3964_info *pInfo)
{
      if (pInfo->nRetry < R3964_MAX_RETRIES) {
            TRACE_PE("transmission failed. Retry #%d", pInfo->nRetry);
            pInfo->bcc = 0;
            put_char(pInfo, STX);
            flush(pInfo);
            pInfo->state = R3964_TX_REQUEST;
            pInfo->nRetry++;
            mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
      } else {
            TRACE_PE("transmission failed after %d retries",
                   R3964_MAX_RETRIES);

            remove_from_tx_queue(pInfo, R3964_TX_FAIL);

            put_char(pInfo, NAK);
            flush(pInfo);
            pInfo->state = R3964_IDLE;

            trigger_transmit(pInfo);
      }
}

static void transmit_block(struct r3964_info *pInfo)
{
      struct tty_struct *tty = pInfo->tty;
      struct r3964_block_header *pBlock = pInfo->tx_first;
      int room = 0;

      if ((tty == NULL) || (pBlock == NULL)) {
            return;
      }

      if (tty->driver->write_room)
            room = tty->driver->write_room(tty);

      TRACE_PS("transmit_block %p, room %d, length %d",
             pBlock, room, pBlock->length);

      while (pInfo->tx_position < pBlock->length) {
            if (room < 2)
                  break;

            if (pBlock->data[pInfo->tx_position] == DLE) {
                  /* send additional DLE char: */
                  put_char(pInfo, DLE);
            }
            put_char(pInfo, pBlock->data[pInfo->tx_position++]);

            room--;
      }

      if ((pInfo->tx_position == pBlock->length) && (room >= 3)) {
            put_char(pInfo, DLE);
            put_char(pInfo, ETX);
            if (pInfo->flags & R3964_BCC) {
                  put_char(pInfo, pInfo->bcc);
            }
            pInfo->state = R3964_WAIT_FOR_TX_ACK;
            mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
      }
      flush(pInfo);
}

static void on_receive_block(struct r3964_info *pInfo)
{
      unsigned int length;
      struct r3964_client_info *pClient;
      struct r3964_block_header *pBlock;

      length = pInfo->rx_position;

      /* compare byte checksum characters: */
      if (pInfo->flags & R3964_BCC) {
            if (pInfo->bcc != pInfo->last_rx) {
                  TRACE_PE("checksum error - got %x but expected %x",
                         pInfo->last_rx, pInfo->bcc);
                  pInfo->flags |= R3964_CHECKSUM;
            }
      }

      /* check for errors (parity, overrun,...): */
      if (pInfo->flags & R3964_ERROR) {
            TRACE_PE("on_receive_block - transmission failed error %x",
                   pInfo->flags & R3964_ERROR);

            put_char(pInfo, NAK);
            flush(pInfo);
            if (pInfo->nRetry < R3964_MAX_RETRIES) {
                  pInfo->state = R3964_WAIT_FOR_RX_REPEAT;
                  pInfo->nRetry++;
                  mod_timer(&pInfo->tmr, jiffies + R3964_TO_RX_PANIC);
            } else {
                  TRACE_PE("on_receive_block - failed after max retries");
                  pInfo->state = R3964_IDLE;
            }
            return;
      }

      /* received block; submit DLE: */
      put_char(pInfo, DLE);
      flush(pInfo);
      del_timer_sync(&pInfo->tmr);
      TRACE_PS(" rx success: got %d chars", length);

      /* prepare struct r3964_block_header: */
      pBlock = kmalloc(length + sizeof(struct r3964_block_header),
                  GFP_KERNEL);
      TRACE_M("on_receive_block - kmalloc %p", pBlock);

      if (pBlock == NULL)
            return;

      pBlock->length = length;
      pBlock->data = ((unsigned char *)pBlock) +
                  sizeof(struct r3964_block_header);
      pBlock->locks = 0;
      pBlock->next = NULL;
      pBlock->owner = NULL;

      memcpy(pBlock->data, pInfo->rx_buf, length);

      /* queue block into rx_queue: */
      add_rx_queue(pInfo, pBlock);

      /* notify attached client processes: */
      for (pClient = pInfo->firstClient; pClient; pClient = pClient->next) {
            if (pClient->sig_flags & R3964_SIG_DATA) {
                  add_msg(pClient, R3964_MSG_DATA, length, R3964_OK,
                        pBlock);
            }
      }
      wake_up_interruptible(&pInfo->read_wait);

      pInfo->state = R3964_IDLE;

      trigger_transmit(pInfo);
}

static void receive_char(struct r3964_info *pInfo, const unsigned char c)
{
      switch (pInfo->state) {
      case R3964_TX_REQUEST:
            if (c == DLE) {
                  TRACE_PS("TX_REQUEST - got DLE");

                  pInfo->state = R3964_TRANSMITTING;
                  pInfo->tx_position = 0;

                  transmit_block(pInfo);
            } else if (c == STX) {
                  if (pInfo->nRetry == 0) {
                        TRACE_PE("TX_REQUEST - init conflict");
                        if (pInfo->priority == R3964_SLAVE) {
                              goto start_receiving;
                        }
                  } else {
                        TRACE_PE("TX_REQUEST - secondary init "
                              "conflict!? Switching to SLAVE mode "
                              "for next rx.");
                        goto start_receiving;
                  }
            } else {
                  TRACE_PE("TX_REQUEST - char != DLE: %x", c);
                  retry_transmit(pInfo);
            }
            break;
      case R3964_TRANSMITTING:
            if (c == NAK) {
                  TRACE_PE("TRANSMITTING - got NAK");
                  retry_transmit(pInfo);
            } else {
                  TRACE_PE("TRANSMITTING - got invalid char");

                  pInfo->state = R3964_WAIT_ZVZ_BEFORE_TX_RETRY;
                  mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
            }
            break;
      case R3964_WAIT_FOR_TX_ACK:
            if (c == DLE) {
                  TRACE_PS("WAIT_FOR_TX_ACK - got DLE");
                  remove_from_tx_queue(pInfo, R3964_OK);

                  pInfo->state = R3964_IDLE;
                  trigger_transmit(pInfo);
            } else {
                  retry_transmit(pInfo);
            }
            break;
      case R3964_WAIT_FOR_RX_REPEAT:
            /* FALLTROUGH */
      case R3964_IDLE:
            if (c == STX) {
                  /* Prevent rx_queue from overflow: */
                  if (pInfo->blocks_in_rx_queue >=
                      R3964_MAX_BLOCKS_IN_RX_QUEUE) {
                        TRACE_PE("IDLE - got STX but no space in "
                                    "rx_queue!");
                        pInfo->state = R3964_WAIT_FOR_RX_BUF;
                        mod_timer(&pInfo->tmr,
                                jiffies + R3964_TO_NO_BUF);
                        break;
                  }
start_receiving:
                  /* Ok, start receiving: */
                  TRACE_PS("IDLE - got STX");
                  pInfo->rx_position = 0;
                  pInfo->last_rx = 0;
                  pInfo->flags &= ~R3964_ERROR;
                  pInfo->state = R3964_RECEIVING;
                  mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
                  pInfo->nRetry = 0;
                  put_char(pInfo, DLE);
                  flush(pInfo);
                  pInfo->bcc = 0;
            }
            break;
      case R3964_RECEIVING:
            if (pInfo->rx_position < RX_BUF_SIZE) {
                  pInfo->bcc ^= c;

                  if (c == DLE) {
                        if (pInfo->last_rx == DLE) {
                              pInfo->last_rx = 0;
                              goto char_to_buf;
                        }
                        pInfo->last_rx = DLE;
                        break;
                  } else if ((c == ETX) && (pInfo->last_rx == DLE)) {
                        if (pInfo->flags & R3964_BCC) {
                              pInfo->state = R3964_WAIT_FOR_BCC;
                              mod_timer(&pInfo->tmr,
                                      jiffies + R3964_TO_ZVZ);
                        } else {
                              on_receive_block(pInfo);
                        }
                  } else {
                        pInfo->last_rx = c;
char_to_buf:
                        pInfo->rx_buf[pInfo->rx_position++] = c;
                        mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
                  }
            }
            /* else: overflow-msg? BUF_SIZE>MTU; should not happen? */
            break;
      case R3964_WAIT_FOR_BCC:
            pInfo->last_rx = c;
            on_receive_block(pInfo);
            break;
      }
}

static void receive_error(struct r3964_info *pInfo, const char flag)
{
      switch (flag) {
      case TTY_NORMAL:
            break;
      case TTY_BREAK:
            TRACE_PE("received break");
            pInfo->flags |= R3964_BREAK;
            break;
      case TTY_PARITY:
            TRACE_PE("parity error");
            pInfo->flags |= R3964_PARITY;
            break;
      case TTY_FRAME:
            TRACE_PE("frame error");
            pInfo->flags |= R3964_FRAME;
            break;
      case TTY_OVERRUN:
            TRACE_PE("frame overrun");
            pInfo->flags |= R3964_OVERRUN;
            break;
      default:
            TRACE_PE("receive_error - unknown flag %d", flag);
            pInfo->flags |= R3964_UNKNOWN;
            break;
      }
}

static void on_timeout(unsigned long priv)
{
      struct r3964_info *pInfo = (void *)priv;

      switch (pInfo->state) {
      case R3964_TX_REQUEST:
            TRACE_PE("TX_REQUEST - timeout");
            retry_transmit(pInfo);
            break;
      case R3964_WAIT_ZVZ_BEFORE_TX_RETRY:
            put_char(pInfo, NAK);
            flush(pInfo);
            retry_transmit(pInfo);
            break;
      case R3964_WAIT_FOR_TX_ACK:
            TRACE_PE("WAIT_FOR_TX_ACK - timeout");
            retry_transmit(pInfo);
            break;
      case R3964_WAIT_FOR_RX_BUF:
            TRACE_PE("WAIT_FOR_RX_BUF - timeout");
            put_char(pInfo, NAK);
            flush(pInfo);
            pInfo->state = R3964_IDLE;
            break;
      case R3964_RECEIVING:
            TRACE_PE("RECEIVING - timeout after %d chars",
                   pInfo->rx_position);
            put_char(pInfo, NAK);
            flush(pInfo);
            pInfo->state = R3964_IDLE;
            break;
      case R3964_WAIT_FOR_RX_REPEAT:
            TRACE_PE("WAIT_FOR_RX_REPEAT - timeout");
            pInfo->state = R3964_IDLE;
            break;
      case R3964_WAIT_FOR_BCC:
            TRACE_PE("WAIT_FOR_BCC - timeout");
            put_char(pInfo, NAK);
            flush(pInfo);
            pInfo->state = R3964_IDLE;
            break;
      }
}

static struct r3964_client_info *findClient(struct r3964_info *pInfo,
            struct pid *pid)
{
      struct r3964_client_info *pClient;

      for (pClient = pInfo->firstClient; pClient; pClient = pClient->next) {
            if (pClient->pid == pid) {
                  return pClient;
            }
      }
      return NULL;
}

static int enable_signals(struct r3964_info *pInfo, struct pid *pid, int arg)
{
      struct r3964_client_info *pClient;
      struct r3964_client_info **ppClient;
      struct r3964_message *pMsg;

      if ((arg & R3964_SIG_ALL) == 0) {
            /* Remove client from client list */
            for (ppClient = &pInfo->firstClient; *ppClient;
                 ppClient = &(*ppClient)->next) {
                  pClient = *ppClient;

                  if (pClient->pid == pid) {
                        TRACE_PS("removing client %d from client list",
                               pid_nr(pid));
                        *ppClient = pClient->next;
                        while (pClient->msg_count) {
                              pMsg = remove_msg(pInfo, pClient);
                              if (pMsg) {
                                    kfree(pMsg);
                                    TRACE_M("enable_signals - msg "
                                          "kfree %p", pMsg);
                              }
                        }
                        put_pid(pClient->pid);
                        kfree(pClient);
                        TRACE_M("enable_signals - kfree %p", pClient);
                        return 0;
                  }
            }
            return -EINVAL;
      } else {
            pClient = findClient(pInfo, pid);
            if (pClient) {
                  /* update signal options */
                  pClient->sig_flags = arg;
            } else {
                  /* add client to client list */
                  pClient = kmalloc(sizeof(struct r3964_client_info),
                              GFP_KERNEL);
                  TRACE_M("enable_signals - kmalloc %p", pClient);
                  if (pClient == NULL)
                        return -ENOMEM;

                  TRACE_PS("add client %d to client list", pid_nr(pid));
                  spin_lock_init(&pClient->lock);
                  pClient->sig_flags = arg;
                  pClient->pid = get_pid(pid);
                  pClient->next = pInfo->firstClient;
                  pClient->first_msg = NULL;
                  pClient->last_msg = NULL;
                  pClient->next_block_to_read = NULL;
                  pClient->msg_count = 0;
                  pInfo->firstClient = pClient;
            }
      }

      return 0;
}

static int read_telegram(struct r3964_info *pInfo, struct pid *pid,
                   unsigned char __user * buf)
{
      struct r3964_client_info *pClient;
      struct r3964_block_header *block;

      if (!buf) {
            return -EINVAL;
      }

      pClient = findClient(pInfo, pid);
      if (pClient == NULL) {
            return -EINVAL;
      }

      block = pClient->next_block_to_read;
      if (!block) {
            return 0;
      } else {
            if (copy_to_user(buf, block->data, block->length))
                  return -EFAULT;

            remove_client_block(pInfo, pClient);
            return block->length;
      }

      return -EINVAL;
}

static void add_msg(struct r3964_client_info *pClient, int msg_id, int arg,
            int error_code, struct r3964_block_header *pBlock)
{
      struct r3964_message *pMsg;
      unsigned long flags;

      if (pClient->msg_count < R3964_MAX_MSG_COUNT - 1) {
queue_the_message:

            pMsg = kmalloc(sizeof(struct r3964_message),
                        error_code ? GFP_ATOMIC : GFP_KERNEL);
            TRACE_M("add_msg - kmalloc %p", pMsg);
            if (pMsg == NULL) {
                  return;
            }

            spin_lock_irqsave(&pClient->lock, flags);

            pMsg->msg_id = msg_id;
            pMsg->arg = arg;
            pMsg->error_code = error_code;
            pMsg->block = pBlock;
            pMsg->next = NULL;

            if (pClient->last_msg == NULL) {
                  pClient->first_msg = pClient->last_msg = pMsg;
            } else {
                  pClient->last_msg->next = pMsg;
                  pClient->last_msg = pMsg;
            }

            pClient->msg_count++;

            if (pBlock != NULL) {
                  pBlock->locks++;
            }
            spin_unlock_irqrestore(&pClient->lock, flags);
      } else {
            if ((pClient->last_msg->msg_id == R3964_MSG_ACK)
                && (pClient->last_msg->error_code == R3964_OVERFLOW)) {
                  pClient->last_msg->arg++;
                  TRACE_PE("add_msg - inc prev OVERFLOW-msg");
            } else {
                  msg_id = R3964_MSG_ACK;
                  arg = 0;
                  error_code = R3964_OVERFLOW;
                  pBlock = NULL;
                  TRACE_PE("add_msg - queue OVERFLOW-msg");
                  goto queue_the_message;
            }
      }
      /* Send SIGIO signal to client process: */
      if (pClient->sig_flags & R3964_USE_SIGIO) {
            kill_pid(pClient->pid, SIGIO, 1);
      }
}

static struct r3964_message *remove_msg(struct r3964_info *pInfo,
                              struct r3964_client_info *pClient)
{
      struct r3964_message *pMsg = NULL;
      unsigned long flags;

      if (pClient->first_msg) {
            spin_lock_irqsave(&pClient->lock, flags);

            pMsg = pClient->first_msg;
            pClient->first_msg = pMsg->next;
            if (pClient->first_msg == NULL) {
                  pClient->last_msg = NULL;
            }

            pClient->msg_count--;
            if (pMsg->block) {
                  remove_client_block(pInfo, pClient);
                  pClient->next_block_to_read = pMsg->block;
            }
            spin_unlock_irqrestore(&pClient->lock, flags);
      }
      return pMsg;
}

static void remove_client_block(struct r3964_info *pInfo,
                        struct r3964_client_info *pClient)
{
      struct r3964_block_header *block;

      TRACE_PS("remove_client_block PID %d", pid_nr(pClient->pid));

      block = pClient->next_block_to_read;
      if (block) {
            block->locks--;
            if (block->locks == 0) {
                  remove_from_rx_queue(pInfo, block);
            }
      }
      pClient->next_block_to_read = NULL;
}

/*************************************************************
 * Line discipline routines
 *************************************************************/

static int r3964_open(struct tty_struct *tty)
{
      struct r3964_info *pInfo;

      TRACE_L("open");
      TRACE_L("tty=%p, PID=%d, disc_data=%p",
            tty, current->pid, tty->disc_data);

      pInfo = kmalloc(sizeof(struct r3964_info), GFP_KERNEL);
      TRACE_M("r3964_open - info kmalloc %p", pInfo);

      if (!pInfo) {
            printk(KERN_ERR "r3964: failed to alloc info structure\n");
            return -ENOMEM;
      }

      pInfo->rx_buf = kmalloc(RX_BUF_SIZE, GFP_KERNEL);
      TRACE_M("r3964_open - rx_buf kmalloc %p", pInfo->rx_buf);

      if (!pInfo->rx_buf) {
            printk(KERN_ERR "r3964: failed to alloc receive buffer\n");
            kfree(pInfo);
            TRACE_M("r3964_open - info kfree %p", pInfo);
            return -ENOMEM;
      }

      pInfo->tx_buf = kmalloc(TX_BUF_SIZE, GFP_KERNEL);
      TRACE_M("r3964_open - tx_buf kmalloc %p", pInfo->tx_buf);

      if (!pInfo->tx_buf) {
            printk(KERN_ERR "r3964: failed to alloc transmit buffer\n");
            kfree(pInfo->rx_buf);
            TRACE_M("r3964_open - rx_buf kfree %p", pInfo->rx_buf);
            kfree(pInfo);
            TRACE_M("r3964_open - info kfree %p", pInfo);
            return -ENOMEM;
      }

      spin_lock_init(&pInfo->lock);
      pInfo->tty = tty;
      init_waitqueue_head(&pInfo->read_wait);
      pInfo->priority = R3964_MASTER;
      pInfo->rx_first = pInfo->rx_last = NULL;
      pInfo->tx_first = pInfo->tx_last = NULL;
      pInfo->rx_position = 0;
      pInfo->tx_position = 0;
      pInfo->last_rx = 0;
      pInfo->blocks_in_rx_queue = 0;
      pInfo->firstClient = NULL;
      pInfo->state = R3964_IDLE;
      pInfo->flags = R3964_DEBUG;
      pInfo->nRetry = 0;

      tty->disc_data = pInfo;
      tty->receive_room = 65536;

      setup_timer(&pInfo->tmr, on_timeout, (unsigned long)pInfo);

      return 0;
}

static void r3964_close(struct tty_struct *tty)
{
      struct r3964_info *pInfo = (struct r3964_info *)tty->disc_data;
      struct r3964_client_info *pClient, *pNext;
      struct r3964_message *pMsg;
      struct r3964_block_header *pHeader, *pNextHeader;
      unsigned long flags;

      TRACE_L("close");

      /*
       * Make sure that our task queue isn't activated.  If it
       * is, take it out of the linked list.
       */
      del_timer_sync(&pInfo->tmr);

      /* Remove client-structs and message queues: */
      pClient = pInfo->firstClient;
      while (pClient) {
            pNext = pClient->next;
            while (pClient->msg_count) {
                  pMsg = remove_msg(pInfo, pClient);
                  if (pMsg) {
                        kfree(pMsg);
                        TRACE_M("r3964_close - msg kfree %p", pMsg);
                  }
            }
            put_pid(pClient->pid);
            kfree(pClient);
            TRACE_M("r3964_close - client kfree %p", pClient);
            pClient = pNext;
      }
      /* Remove jobs from tx_queue: */
      spin_lock_irqsave(&pInfo->lock, flags);
      pHeader = pInfo->tx_first;
      pInfo->tx_first = pInfo->tx_last = NULL;
      spin_unlock_irqrestore(&pInfo->lock, flags);

      while (pHeader) {
            pNextHeader = pHeader->next;
            kfree(pHeader);
            pHeader = pNextHeader;
      }

      /* Free buffers: */
      wake_up_interruptible(&pInfo->read_wait);
      kfree(pInfo->rx_buf);
      TRACE_M("r3964_close - rx_buf kfree %p", pInfo->rx_buf);
      kfree(pInfo->tx_buf);
      TRACE_M("r3964_close - tx_buf kfree %p", pInfo->tx_buf);
      kfree(pInfo);
      TRACE_M("r3964_close - info kfree %p", pInfo);
}

static ssize_t r3964_read(struct tty_struct *tty, struct file *file,
                    unsigned char __user * buf, size_t nr)
{
      struct r3964_info *pInfo = (struct r3964_info *)tty->disc_data;
      struct r3964_client_info *pClient;
      struct r3964_message *pMsg;
      struct r3964_client_message theMsg;
      int count;

      TRACE_L("read()");

      pClient = findClient(pInfo, task_pid(current));
      if (pClient) {
            pMsg = remove_msg(pInfo, pClient);
            if (pMsg == NULL) {
                  /* no messages available. */
                  if (file->f_flags & O_NONBLOCK) {
                        return -EAGAIN;
                  }
                  /* block until there is a message: */
                  wait_event_interruptible(pInfo->read_wait,
                              (pMsg = remove_msg(pInfo, pClient)));
            }

            /* If we still haven't got a message, we must have been signalled */

            if (!pMsg)
                  return -EINTR;

            /* deliver msg to client process: */
            theMsg.msg_id = pMsg->msg_id;
            theMsg.arg = pMsg->arg;
            theMsg.error_code = pMsg->error_code;
            count = sizeof(struct r3964_client_message);

            kfree(pMsg);
            TRACE_M("r3964_read - msg kfree %p", pMsg);

            if (copy_to_user(buf, &theMsg, count))
                  return -EFAULT;

            TRACE_PS("read - return %d", count);
            return count;
      }
      return -EPERM;
}

static ssize_t r3964_write(struct tty_struct *tty, struct file *file,
                     const unsigned char *data, size_t count)
{
      struct r3964_info *pInfo = (struct r3964_info *)tty->disc_data;
      struct r3964_block_header *pHeader;
      struct r3964_client_info *pClient;
      unsigned char *new_data;

      TRACE_L("write request, %d characters", count);
/* 
 * Verify the pointers 
 */

      if (!pInfo)
            return -EIO;

/*
 * Ensure that the caller does not wish to send too much.
 */
      if (count > R3964_MTU) {
            if (pInfo->flags & R3964_DEBUG) {
                  TRACE_L(KERN_WARNING "r3964_write: truncating user "
                        "packet from %u to mtu %d", count, R3964_MTU);
            }
            count = R3964_MTU;
      }
/*
 * Allocate a buffer for the data and copy it from the buffer with header prepended
 */
      new_data = kmalloc(count + sizeof(struct r3964_block_header),
                  GFP_KERNEL);
      TRACE_M("r3964_write - kmalloc %p", new_data);
      if (new_data == NULL) {
            if (pInfo->flags & R3964_DEBUG) {
                  printk(KERN_ERR "r3964_write: no memory\n");
            }
            return -ENOSPC;
      }

      pHeader = (struct r3964_block_header *)new_data;
      pHeader->data = new_data + sizeof(struct r3964_block_header);
      pHeader->length = count;
      pHeader->locks = 0;
      pHeader->owner = NULL;

      pClient = findClient(pInfo, task_pid(current));
      if (pClient) {
            pHeader->owner = pClient;
      }

      memcpy(pHeader->data, data, count); /* We already verified this */

      if (pInfo->flags & R3964_DEBUG) {
            dump_block(pHeader->data, count);
      }

/*
 * Add buffer to transmit-queue:
 */
      add_tx_queue(pInfo, pHeader);
      trigger_transmit(pInfo);

      return 0;
}

static int r3964_ioctl(struct tty_struct *tty, struct file *file,
            unsigned int cmd, unsigned long arg)
{
      struct r3964_info *pInfo = (struct r3964_info *)tty->disc_data;
      if (pInfo == NULL)
            return -EINVAL;
      switch (cmd) {
      case R3964_ENABLE_SIGNALS:
            return enable_signals(pInfo, task_pid(current), arg);
      case R3964_SETPRIORITY:
            if (arg < R3964_MASTER || arg > R3964_SLAVE)
                  return -EINVAL;
            pInfo->priority = arg & 0xff;
            return 0;
      case R3964_USE_BCC:
            if (arg)
                  pInfo->flags |= R3964_BCC;
            else
                  pInfo->flags &= ~R3964_BCC;
            return 0;
      case R3964_READ_TELEGRAM:
            return read_telegram(pInfo, task_pid(current),
                        (unsigned char __user *)arg);
      default:
            return -ENOIOCTLCMD;
      }
}

static void r3964_set_termios(struct tty_struct *tty, struct ktermios *old)
{
      TRACE_L("set_termios");
}

/* Called without the kernel lock held - fine */
static unsigned int r3964_poll(struct tty_struct *tty, struct file *file,
                  struct poll_table_struct *wait)
{
      struct r3964_info *pInfo = (struct r3964_info *)tty->disc_data;
      struct r3964_client_info *pClient;
      struct r3964_message *pMsg = NULL;
      unsigned long flags;
      int result = POLLOUT;

      TRACE_L("POLL");

      pClient = findClient(pInfo, task_pid(current));
      if (pClient) {
            poll_wait(file, &pInfo->read_wait, wait);
            spin_lock_irqsave(&pInfo->lock, flags);
            pMsg = pClient->first_msg;
            spin_unlock_irqrestore(&pInfo->lock, flags);
            if (pMsg)
                  result |= POLLIN | POLLRDNORM;
      } else {
            result = -EINVAL;
      }
      return result;
}

static void r3964_receive_buf(struct tty_struct *tty, const unsigned char *cp,
                  char *fp, int count)
{
      struct r3964_info *pInfo = (struct r3964_info *)tty->disc_data;
      const unsigned char *p;
      char *f, flags = 0;
      int i;

      for (i = count, p = cp, f = fp; i; i--, p++) {
            if (f)
                  flags = *f++;
            if (flags == TTY_NORMAL) {
                  receive_char(pInfo, *p);
            } else {
                  receive_error(pInfo, flags);
            }

      }
}

MODULE_LICENSE("GPL");
MODULE_ALIAS_LDISC(N_R3964);

Generated by  Doxygen 1.6.0   Back to index