n_r3964.c

linux 内核源代码

/* 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);
	}
}