Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 1416 insertions, 0 deletions

diff --git a/drivers/char/n_r3964.c b/drivers/char/n_r3964.c
new file mode 100644
index 000000000000..3883073ab48f
--- /dev/null
+++ b/drivers/char/n_r3964.c
@@ -0,0 +1,1416 @@
+/* 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...) /**/
+#endif
+
+#ifdef DEBUG_PROTO_S
+#define TRACE_PS(format, args...) printk("r3964: " format "\n" , ## args);
+#else
+#define TRACE_PS(fmt, arg...) /**/
+#endif
+
+#ifdef DEBUG_PROTO_E
+#define TRACE_PE(format, args...) printk("r3964: " format "\n" , ## args);
+#else
+#define TRACE_PE(fmt, arg...) /**/
+#endif
+
+#ifdef DEBUG_LDISC
+#define TRACE_L(format, args...) printk("r3964: " format "\n" , ## args);
+#else
+#define TRACE_L(fmt, arg...) /**/
+#endif
+
+#ifdef DEBUG_QUEUE
+#define TRACE_Q(format, args...) printk("r3964: " format "\n" , ## args);
+#else
+#define TRACE_Q(fmt, arg...) /**/
+#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, pid_t pid, int arg);
+static int read_telegram(struct r3964_info *pInfo, pid_t 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 termios * 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 int  r3964_receive_room(struct tty_struct *tty);
+
+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,
+        .receive_room = r3964_receive_room,
+};
+
+
+
+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_register_ldisc(N_R3964, NULL);
+   
+   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=%x", (int)tty_ldisc_N_R3964.open);
+       TRACE_L("tty_ldisc_N_R3964 = %x", (int)&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 %x, length %d, tx_first = %x", 
+          (int)pHeader, pHeader->length, (int)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: %x, length %d - ",
+          (int)pHeader, (int)pHeader->length );
+   for(pDump=pHeader;pDump;pDump=pDump->next)
+         printk("%x ", (int)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 %x",(int)pHeader);
+
+   TRACE_Q("remove_from_tx_queue: tx_first = %x, tx_last = %x",
+          (int)pInfo->tx_first, (int)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: %x, length = %d, rx_first = %x, count = %d",
+          (int)pHeader, pHeader->length,
+          (int)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 = %x, rx_last = %x, count = %d",
+          (int)pInfo->rx_first, (int)pInfo->rx_last, pInfo->blocks_in_rx_queue );
+   TRACE_Q("remove_from_rx_queue: %x, length %d",
+          (int)pHeader, (int)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 %x",(int)pHeader);
+
+   TRACE_Q("remove_from_rx_queue: rx_first = %x, rx_last = %x, count = %d",
+          (int)pInfo->rx_first, (int)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 %x, room %d, length %d", 
+          (int)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 %x",(int)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, 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, 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, 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, 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, pid_t 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, pid_t 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);
+            *ppClient = pClient->next;
+            while(pClient->msg_count)
+            {
+               pMsg=remove_msg(pInfo, pClient);
+               if(pMsg)
+               {
+                  kfree(pMsg);
+                  TRACE_M("enable_signals - msg kfree %x",(int)pMsg);
+               }
+            }
+            kfree(pClient);
+            TRACE_M("enable_signals - kfree %x",(int)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 %x",(int)pClient);
+         if(pClient==NULL)
+            return -ENOMEM;
+
+         TRACE_PS("add client %d to client list", pid);
+         spin_lock_init(&pClient->lock);
+         pClient->sig_flags=arg;
+         pClient->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, pid_t 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), GFP_KERNEL);
+      TRACE_M("add_msg - kmalloc %x",(int)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_proc(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", 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=%x, PID=%d, disc_data=%x", 
+          (int)tty, current->pid, (int)tty->disc_data);
+   
+   pInfo=kmalloc(sizeof(struct r3964_info), GFP_KERNEL); 
+   TRACE_M("r3964_open - info kmalloc %x",(int)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 %x",(int)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 %x",(int)pInfo);
+      return -ENOMEM;
+   }
+   
+   pInfo->tx_buf = kmalloc(TX_BUF_SIZE, GFP_KERNEL);
+   TRACE_M("r3964_open - tx_buf kmalloc %x",(int)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 %x",(int)pInfo->rx_buf);
+      kfree(pInfo);
+      TRACE_M("r3964_open - info kfree %x",(int)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;
+
+   init_timer(&pInfo->tmr);
+   pInfo->tmr.data = (unsigned long)pInfo;
+   pInfo->tmr.function = on_timeout;
+
+   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 %x",(int)pMsg);
+          }
+       }
+       kfree(pClient);
+       TRACE_M("r3964_close - client kfree %x",(int)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 %x",(int)pInfo->rx_buf);
+    kfree(pInfo->tx_buf);
+    TRACE_M("r3964_close - tx_buf kfree %x",(int)pInfo->tx_buf);
+    kfree(pInfo);
+    TRACE_M("r3964_close - info kfree %x",(int)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;
+   DECLARE_WAITQUEUE (wait, current);
+   
+   int pid = current->pid;
+   int count;
+   
+   TRACE_L("read()");
+ 
+   pClient=findClient(pInfo, pid);
+   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: */
+         add_wait_queue(&pInfo->read_wait, &wait);
+repeat:
+         current->state = TASK_INTERRUPTIBLE;
+         pMsg = remove_msg(pInfo, pClient);
+         if (!pMsg && !signal_pending(current))
+                 {
+            schedule();
+            goto repeat;
+         }
+         current->state = TASK_RUNNING;
+         remove_wait_queue(&pInfo->read_wait, &wait);
+      }
+      
+      /* 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 %x",(int)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;
+   int pid;
+   
+   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 %x",(int)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;
+   
+   pid=current->pid;
+   
+   pClient=findClient(pInfo, pid);
+   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, current->pid, 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, current->pid, (unsigned char __user *)arg);
+      default:
+         return -ENOIOCTLCMD;
+   }
+}
+
+static void r3964_set_termios(struct tty_struct *tty, struct termios * 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;
+   int pid=current->pid;
+   struct r3964_client_info *pClient;
+   struct r3964_message *pMsg=NULL;
+   unsigned long flags;
+   int result = POLLOUT;
+
+   TRACE_L("POLL");
+
+   pClient=findClient(pInfo,pid);
+   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);
+        }
+        
+    }
+}
+
+static int r3964_receive_room(struct tty_struct *tty)
+{
+   TRACE_L("receive_room");
+   return -1;
+}
+
+
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_LDISC(N_R3964);