Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1265 insertions, 0 deletions

diff --git a/drivers/tty/n_r3964.c b/drivers/tty/n_r3964.c
new file mode 100644
index 000000000..a3969b773
--- /dev/null
+++ b/drivers/tty/n_r3964.c
@@ -0,0 +1,1265 @@
+// SPDX-License-Identifier: GPL-1.0+
+/* r3964 linediscipline for linux
+ *
+ * -----------------------------------------------------------
+ * Copyright by 
+ * Philips Automation Projects
+ * Kassel (Germany)
+ * -----------------------------------------------------------
+ * 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 <linux/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(struct timer_list *t);
+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 __poll_t 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_ops 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->tty->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;
+	/* FIXME: put_char should not be called from an IRQ */
+	tty_put_char(tty, ch);
+	pInfo->bcc ^= ch;
+}
+
+static void flush(struct r3964_info *pInfo)
+{
+	struct tty_struct *tty = pInfo->tty;
+
+	if (tty == NULL || tty->ops->flush_chars == NULL)
+		return;
+	tty->ops->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;
+	}
+
+	room = tty_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->tty->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:
+		/* FALLTHROUGH */
+	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(struct timer_list *t)
+{
+	struct r3964_info *pInfo = from_timer(pInfo, t, tmr);
+
+	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);
+	mutex_init(&pInfo->read_lock);
+	pInfo->tty = tty;
+	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;
+
+	timer_setup(&pInfo->tmr, on_timeout, 0);
+
+	return 0;
+}
+
+static void r3964_close(struct tty_struct *tty)
+{
+	struct r3964_info *pInfo = 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: */
+	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 = tty->disc_data;
+	struct r3964_client_info *pClient;
+	struct r3964_message *pMsg;
+	struct r3964_client_message theMsg;
+	int ret;
+
+	TRACE_L("read()");
+
+	/*
+	 *	Internal serialization of reads.
+	 */
+	if (file->f_flags & O_NONBLOCK) {
+		if (!mutex_trylock(&pInfo->read_lock))
+			return -EAGAIN;
+	} else {
+		if (mutex_lock_interruptible(&pInfo->read_lock))
+			return -ERESTARTSYS;
+	}
+
+	pClient = findClient(pInfo, task_pid(current));
+	if (pClient) {
+		pMsg = remove_msg(pInfo, pClient);
+		if (pMsg == NULL) {
+			/* no messages available. */
+			if (tty_io_nonblock(tty, file)) {
+				ret = -EAGAIN;
+				goto unlock;
+			}
+			/* block until there is a message: */
+			wait_event_interruptible(tty->read_wait,
+					(pMsg = remove_msg(pInfo, pClient)));
+		}
+
+		/* If we still haven't got a message, we must have been signalled */
+
+		if (!pMsg) {
+			ret = -EINTR;
+			goto unlock;
+		}
+
+		/* deliver msg to client process: */
+		theMsg.msg_id = pMsg->msg_id;
+		theMsg.arg = pMsg->arg;
+		theMsg.error_code = pMsg->error_code;
+		ret = sizeof(struct r3964_client_message);
+
+		kfree(pMsg);
+		TRACE_M("r3964_read - msg kfree %p", pMsg);
+
+		if (copy_to_user(buf, &theMsg, ret)) {
+			ret = -EFAULT;
+			goto unlock;
+		}
+
+		TRACE_PS("read - return %d", ret);
+		goto unlock;
+	}
+	ret = -EPERM;
+unlock:
+	mutex_unlock(&pInfo->read_lock);
+	return ret;
+}
+
+static ssize_t r3964_write(struct tty_struct *tty, struct file *file,
+			   const unsigned char *data, size_t count)
+{
+	struct r3964_info *pInfo = 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 = 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 __poll_t r3964_poll(struct tty_struct *tty, struct file *file,
+			struct poll_table_struct *wait)
+{
+	struct r3964_info *pInfo = tty->disc_data;
+	struct r3964_client_info *pClient;
+	struct r3964_message *pMsg = NULL;
+	unsigned long flags;
+	__poll_t result = EPOLLOUT;
+
+	TRACE_L("POLL");
+
+	pClient = findClient(pInfo, task_pid(current));
+	if (pClient) {
+		poll_wait(file, &tty->read_wait, wait);
+		spin_lock_irqsave(&pInfo->lock, flags);
+		pMsg = pClient->first_msg;
+		spin_unlock_irqrestore(&pInfo->lock, flags);
+		if (pMsg)
+			result |= EPOLLIN | EPOLLRDNORM;
+	} 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 = tty->disc_data;
+	const unsigned char *p;
+	char *f, flags = TTY_NORMAL;
+	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);