arcnet.c

h内核

/*
 * Linux ARCnet driver - device-independent routines
 * 
 * Written 1997 by David Woodhouse.
 * Written 1994-1999 by Avery Pennarun.
 * Written 1999-2000 by Martin Mares <[e-mail]>.
 * Derived from skeleton.c by Donald Becker.
 *
 * Special thanks to Contemporary Controls, Inc. (www.ccontrols.com)
 *  for sponsoring the further development of this driver.
 *
 * **********************
 *
 * The original copyright was as follows:
 *
 * skeleton.c Written 1993 by Donald Becker.
 * Copyright 1993 United States Government as represented by the
 * Director, National Security Agency.  This software may only be used
 * and distributed according to the terms of the GNU General Public License as
 * modified by SRC, incorporated herein by reference.
 *
 * **********************
 * 
 * The change log is now in a file called ChangeLog in this directory.
 *
 * Sources:
 *  - Crynwr arcnet.com/arcether.com packet drivers.
 *  - arcnet.c v0.00 dated 1/1/94 and apparently by 
 *     Donald Becker - it didn't work :)
 *  - skeleton.c v0.05 dated 11/16/93 by Donald Becker
 *     (from Linux Kernel 1.1.45)
 *  - RFC's 1201 and 1051 - re: TCP/IP over ARCnet
 *  - The official ARCnet COM9026 data sheets (!) thanks to
 *     Ken Cornetet <[e-mail]>
 *  - The official ARCnet COM20020 data sheets.
 *  - Information on some more obscure ARCnet controller chips, thanks
 *     to the nice people at SMSC.
 *  - net/inet/eth.c (from kernel 1.1.50) for header-building info.
 *  - Alternate Linux ARCnet source by V.Shergin <[e-mail]>
 *  - Textual information and more alternate source from Joachim Koenig
 *     <[e-mail]>
 */

#define VERSION "arcnet: v3.93 BETA 2000/04/29 - by Avery Pennarun et al.\n"

#include <linux/module.h>
#include <linux/config.h>
#include <linux/types.h>
#include <linux/delay.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <net/arp.h>
#include <linux/init.h>
#include <linux/arcdevice.h>

/* "do nothing" functions for protocol drivers */
static void null_rx(struct net_device *dev, int bufnum,
		    struct archdr *pkthdr, int length);
static int null_build_header(struct sk_buff *skb, struct net_device *dev,
			     unsigned short type, uint8_t daddr);
static int null_prepare_tx(struct net_device *dev, struct archdr *pkt,
			   int length, int bufnum);


/*
 * one ArcProto per possible proto ID.  None of the elements of
 * arc_proto_map are allowed to be NULL; they will get set to
 * arc_proto_default instead.  It also must not be NULL; if you would like
 * to set it to NULL, set it to &arc_proto_null instead.
 */
 struct ArcProto *arc_proto_map[256], *arc_proto_default,
   *arc_bcast_proto, *arc_raw_proto;

struct ArcProto arc_proto_null =
{
	.suffix		= '?',
	.mtu		= XMTU,
	.is_ip          = 0,
	.rx		= null_rx,
	.build_header	= null_build_header,
	.prepare_tx	= null_prepare_tx,
	.continue_tx    = NULL,
	.ack_tx         = NULL
};

/* Exported function prototypes */
int arcnet_debug = ARCNET_DEBUG;

EXPORT_SYMBOL(arc_proto_map);
EXPORT_SYMBOL(arc_proto_default);
EXPORT_SYMBOL(arc_bcast_proto);
EXPORT_SYMBOL(arc_raw_proto);
EXPORT_SYMBOL(arc_proto_null);
EXPORT_SYMBOL(arcnet_unregister_proto);
EXPORT_SYMBOL(arcnet_debug);
EXPORT_SYMBOL(alloc_arcdev);
EXPORT_SYMBOL(arcnet_interrupt);

/* Internal function prototypes */
static int arcnet_open(struct net_device *dev);
static int arcnet_close(struct net_device *dev);
static int arcnet_send_packet(struct sk_buff *skb, struct net_device *dev);
static void arcnet_timeout(struct net_device *dev);
static int arcnet_header(struct sk_buff *skb, struct net_device *dev,
			 unsigned short type, void *daddr, void *saddr,
			 unsigned len);
static int arcnet_rebuild_header(struct sk_buff *skb);
static struct net_device_stats *arcnet_get_stats(struct net_device *dev);
static int go_tx(struct net_device *dev);

static int debug = ARCNET_DEBUG;
module_param(debug, int, 0);
MODULE_LICENSE("GPL");

static int __init arcnet_init(void)
{
	int count;

	arcnet_debug = debug;

	printk(VERSION);

#ifdef ALPHA_WARNING
	BUGLVL(D_EXTRA) {
		printk("arcnet: ***\n"
		"arcnet: * Read arcnet.txt for important release notes!\n"
		       "arcnet: *\n"
		       "arcnet: * This is an ALPHA version! (Last stable release: v3.02)  E-mail\n"
		       "arcnet: * me if you have any questions, comments, or bug reports.\n"
		       "arcnet: ***\n");
	}
#endif

	/* initialize the protocol map */
	arc_raw_proto = arc_proto_default = arc_bcast_proto = &arc_proto_null;
	for (count = 0; count < 256; count++)
		arc_proto_map[count] = arc_proto_default;

	BUGLVL(D_DURING)
	    printk("arcnet: struct sizes: %Zd %Zd %Zd %Zd %Zd\n",
		 sizeof(struct arc_hardware), sizeof(struct arc_rfc1201),
		sizeof(struct arc_rfc1051), sizeof(struct arc_eth_encap),
		   sizeof(struct archdr));

	return 0;
}

static void __exit arcnet_exit(void)
{
}

module_init(arcnet_init);
module_exit(arcnet_exit);

/*
 * Dump the contents of an sk_buff
 */
#if ARCNET_DEBUG_MAX & D_SKB
void arcnet_dump_skb(struct net_device *dev,
		     struct sk_buff *skb, char *desc)
{
	int i;

	printk(KERN_DEBUG "%6s: skb dump (%s) follows:", dev->name, desc);
	for (i = 0; i < skb->len; i++) {
		if (i % 16 == 0)
			printk("\n" KERN_DEBUG "[%04X] ", i);
		printk("%02X ", ((u_char *) skb->data)[i]);
	}
	printk("\n");
}

EXPORT_SYMBOL(arcnet_dump_skb);
#endif


/*
 * Dump the contents of an ARCnet buffer
 */
#if (ARCNET_DEBUG_MAX & (D_RX | D_TX))
void arcnet_dump_packet(struct net_device *dev, int bufnum, char *desc,
			int take_arcnet_lock)
{
	struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
	int i, length;
	unsigned long flags = 0;
	static uint8_t buf[512];

	/* hw.copy_from_card expects IRQ context so take the IRQ lock
	   to keep it single threaded */
	if(take_arcnet_lock)
		spin_lock_irqsave(&lp->lock, flags);

	lp->hw.copy_from_card(dev, bufnum, 0, buf, 512);
	if(take_arcnet_lock)
		spin_unlock_irqrestore(&lp->lock, flags);

	/* if the offset[0] byte is nonzero, this is a 256-byte packet */
	length = (buf[2] ? 256 : 512);

	printk(KERN_DEBUG "%6s: packet dump (%s) follows:", dev->name, desc);
	for (i = 0; i < length; i++) {
		if (i % 16 == 0)
			printk("\n" KERN_DEBUG "[%04X] ", i);
		printk("%02X ", buf[i]);
	}
	printk("\n");

}

EXPORT_SYMBOL(arcnet_dump_packet);
#endif


/*
 * Unregister a protocol driver from the arc_proto_map.  Protocol drivers
 * are responsible for registering themselves, but the unregister routine
 * is pretty generic so we'll do it here.
 */
void arcnet_unregister_proto(struct ArcProto *proto)
{
	int count;

	if (arc_proto_default == proto)
		arc_proto_default = &arc_proto_null;
	if (arc_bcast_proto == proto)
		arc_bcast_proto = arc_proto_default;
	if (arc_raw_proto == proto)
		arc_raw_proto = arc_proto_default;

	for (count = 0; count < 256; count++) {
		if (arc_proto_map[count] == proto)
			arc_proto_map[count] = arc_proto_default;
	}
}


/*
 * Add a buffer to the queue.  Only the interrupt handler is allowed to do
 * this, unless interrupts are disabled.
 * 
 * Note: we don't check for a full queue, since there aren't enough buffers
 * to more than fill it.
 */
static void release_arcbuf(struct net_device *dev, int bufnum)
{
	struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
	int i;

	lp->buf_queue[lp->first_free_buf++] = bufnum;
	lp->first_free_buf %= 5;

	BUGLVL(D_DURING) {
		BUGMSG(D_DURING, "release_arcbuf: freed #%d; buffer queue is now: ",
		       bufnum);
		for (i = lp->next_buf; i != lp->first_free_buf; i = ++i % 5)
			BUGMSG2(D_DURING, "#%d ", lp->buf_queue[i]);
		BUGMSG2(D_DURING, "\n");
	}
}


/*
 * Get a buffer from the queue.  If this returns -1, there are no buffers
 * available.
 */
static int get_arcbuf(struct net_device *dev)
{
	struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
	int buf = -1, i;

	if (!atomic_dec_and_test(&lp->buf_lock)) {
		/* already in this function */
		BUGMSG(D_NORMAL, "get_arcbuf: overlap (%d)!\n",
		       lp->buf_lock.counter);
	}
	else {			/* we can continue */
		if (lp->next_buf >= 5)
			lp->next_buf -= 5;

		if (lp->next_buf == lp->first_free_buf)
			BUGMSG(D_NORMAL, "get_arcbuf: BUG: no buffers are available??\n");
		else {
			buf = lp->buf_queue[lp->next_buf++];
			lp->next_buf %= 5;
		}
	}


	BUGLVL(D_DURING) {
		BUGMSG(D_DURING, "get_arcbuf: got #%d; buffer queue is now: ", buf);
		for (i = lp->next_buf; i != lp->first_free_buf; i = ++i % 5)
			BUGMSG2(D_DURING, "#%d ", lp->buf_queue[i]);
		BUGMSG2(D_DURING, "\n");
	}

	atomic_inc(&lp->buf_lock);
	return buf;
}


static int choose_mtu(void)
{
	int count, mtu = 65535;

	/* choose the smallest MTU of all available encaps */
	for (count = 0; count < 256; count++) {
		if (arc_proto_map[count] != &arc_proto_null
		    && arc_proto_map[count]->mtu < mtu) {
			mtu = arc_proto_map[count]->mtu;
		}
	}

	return mtu == 65535 ? XMTU : mtu;
}


/* Setup a struct device for ARCnet. */
static void arcdev_setup(struct net_device *dev)
{
	dev->type = ARPHRD_ARCNET;
	dev->hard_header_len = sizeof(struct archdr);
	dev->mtu = choose_mtu();

	dev->addr_len = ARCNET_ALEN;
	dev->tx_queue_len = 100;
	dev->broadcast[0] = 0x00;	/* for us, broadcasts are address 0 */
	dev->watchdog_timeo = TX_TIMEOUT;

	/* New-style flags. */
	dev->flags = IFF_BROADCAST;

	/*
	 * Put in this stuff here, so we don't have to export the symbols to
	 * the chipset drivers.
	 */
	dev->open = arcnet_open;
	dev->stop = arcnet_close;
	dev->hard_start_xmit = arcnet_send_packet;
	dev->tx_timeout = arcnet_timeout;
	dev->get_stats = arcnet_get_stats;
	dev->hard_header = arcnet_header;
	dev->rebuild_header = arcnet_rebuild_header;
}

struct net_device *alloc_arcdev(char *name)
{
	struct net_device *dev;

	dev = alloc_netdev(sizeof(struct arcnet_local),
			   name && *name ? name : "arc%d", arcdev_setup);
	if(dev) {
		struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
		spin_lock_init(&lp->lock);
	}

	return dev;
}

/*
 * Open/initialize the board.  This is called sometime after booting when
 * the 'ifconfig' program is run.
 *
 * This routine should set everything up anew at each open, even registers
 * that "should" only need to be set once at boot, so that there is
 * non-reboot way to recover if something goes wrong.
 */
static int arcnet_open(struct net_device *dev)
{
	struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
	int count, newmtu, error;

	BUGMSG(D_INIT,"opened.");

	if (!try_module_get(lp->hw.owner))
		return -ENODEV;

	BUGLVL(D_PROTO) {
		int count;
		BUGMSG(D_PROTO, "protocol map (default is '%c'): ",
		       arc_proto_default->suffix);
		for (count = 0; count < 256; count++)
			BUGMSG2(D_PROTO, "%c", arc_proto_map[count]->suffix);
		BUGMSG2(D_PROTO, "\n");
	}


	BUGMSG(D_INIT, "arcnet_open: resetting card.\n");

	/* try to put the card in a defined state - if it fails the first
	 * time, actually reset it.
	 */
	error = -ENODEV;
	if (ARCRESET(0) && ARCRESET(1))
		goto out_module_put;

	newmtu = choose_mtu();
	if (newmtu < dev->mtu)
		dev->mtu = newmtu;

	BUGMSG(D_INIT, "arcnet_open: mtu: %d.\n", dev->mtu);

	/* autodetect the encapsulation for each host. */
	memset(lp->default_proto, 0, sizeof(lp->default_proto));

	/* the broadcast address is special - use the 'bcast' protocol */
	for (count = 0; count < 256; count++) {
		if (arc_proto_map[count] == arc_bcast_proto) {
			lp->default_proto[0] = count;
			break;
		}
	}

	/* initialize buffers */
	atomic_set(&lp->buf_lock, 1);

	lp->next_buf = lp->first_free_buf = 0;
	release_arcbuf(dev, 0);
	release_arcbuf(dev, 1);
	release_arcbuf(dev, 2);
	release_arcbuf(dev, 3);
	lp->cur_tx = lp->next_tx = -1;
	lp->cur_rx = -1;

	lp->rfc1201.sequence = 1;

	/* bring up the hardware driver */
	if (lp->hw.open)
		lp->hw.open(dev);

	if (dev->dev_addr[0] == 0)
		BUGMSG(D_NORMAL, "WARNING!  Station address 00 is reserved "
		       "for broadcasts!\n");
	else if (dev->dev_addr[0] == 255)
		BUGMSG(D_NORMAL, "WARNING!  Station address FF may confuse "
		       "DOS networking programs!\n");

	BUGMSG(D_DEBUG, "%s: %d: %s\n",__FILE__,__LINE__,__FUNCTION__);
	if (ASTATUS() & RESETflag) {
	  	BUGMSG(D_DEBUG, "%s: %d: %s\n",__FILE__,__LINE__,__FUNCTION__);
		ACOMMAND(CFLAGScmd | RESETclear);
	}


	BUGMSG(D_DEBUG, "%s: %d: %s\n",__FILE__,__LINE__,__FUNCTION__);
	/* make sure we're ready to receive IRQ's. */
	AINTMASK(0);
	udelay(1);		/* give it time to set the mask before
				 * we reset it again. (may not even be
				 * necessary)
				 */
	BUGMSG(D_DEBUG, "%s: %d: %s\n",__FILE__,__LINE__,__FUNCTION__);
	lp->intmask = NORXflag | RECONflag;
	AINTMASK(lp->intmask);
	BUGMSG(D_DEBUG, "%s: %d: %s\n",__FILE__,__LINE__,__FUNCTION__);

	netif_start_queue(dev);

	return 0;

 out_module_put:
	module_put(lp->hw.owner);
	return error;
}


/* The inverse routine to arcnet_open - shuts down the card. */
static int arcnet_close(struct net_device *dev)
{
	struct arcnet_local *lp = (struct arcnet_local *) dev->priv;

	netif_stop_queue(dev);

	/* flush TX and disable RX */
	AINTMASK(0);
	ACOMMAND(NOTXcmd);	/* stop transmit */
	ACOMMAND(NORXcmd);	/* disable receive */
	mdelay(1);

	/* shut down the card */
	lp->hw.close(dev);
	module_put(lp->hw.owner);
	return 0;
}


static int arcnet_header(struct sk_buff *skb, struct net_device *dev,
			 unsigned short type, void *daddr, void *saddr,
			 unsigned len)
{
	struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
	uint8_t _daddr, proto_num;
	struct ArcProto *proto;

	BUGMSG(D_DURING,
	    "create header from %d to %d; protocol %d (%Xh); size %u.\n",
	       saddr ? *(uint8_t *) saddr : -1,
	       daddr ? *(uint8_t *) daddr : -1,
	       type, type, len);

	if (skb->len!=0 && len != skb->len)
		BUGMSG(D_NORMAL, "arcnet_header: Yikes!  skb->len(%d) != len(%d)!\n",
		       skb->len, len);


  	/* Type is host order - ? */
  	if(type == ETH_P_ARCNET) {
  		proto = arc_raw_proto;
  		BUGMSG(D_DEBUG, "arc_raw_proto used. proto='%c'\n",proto->suffix);
  		_daddr = daddr ? *(uint8_t *) daddr : 0;
  	}
	else if (!daddr) {
		/*
		 * if the dest addr isn't provided, we can't choose an encapsulation!
		 * Store the packet type (eg. ETH_P_IP) for now, and we'll push on a
		 * real header when we do rebuild_header.
		 */
		*(uint16_t *) skb_push(skb, 2) = type;
		if (skb->nh.raw - skb->mac.raw != 2)
			BUGMSG(D_NORMAL, "arcnet_header: Yikes!  diff (%d) is not 2!\n",
			       (int)(skb->nh.raw - skb->mac.raw));
		return -2;	/* return error -- can't transmit yet! */
	}
	else {
		/* otherwise, we can just add the header as usual. */
		_daddr = *(uint8_t *) daddr;
		proto_num = lp->default_proto[_daddr];
		proto = arc_proto_map[proto_num];
		BUGMSG(D_DURING, "building header for %02Xh using protocol '%c'\n",
		       proto_num, proto->suffix);
		if (proto == &arc_proto_null && arc_bcast_proto != proto) {
			BUGMSG(D_DURING, "actually, let's use '%c' instead.\n",
			       arc_bcast_proto->suffix);
			proto = arc_bcast_proto;
		}
	}
	return proto->build_header(skb, dev, type, _daddr);
}


/* 
 * Rebuild the ARCnet hard header. This is called after an ARP (or in the
 * future other address resolution) has completed on this sk_buff. We now
 * let ARP fill in the destination field.
 */
static int arcnet_rebuild_header(struct sk_buff *skb)
{
	struct net_device *dev = skb->dev;
	struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
	int status = 0;		/* default is failure */
	unsigned short type;
	uint8_t daddr=0;