arcnet.c

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/*
 * 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: v3.94 BETA 2007/02/08 - by Avery Pennarun et al.\n"

#include <linux/module.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>
#include <linux/jiffies.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);

static void arcnet_rx(struct net_device *dev, 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;

static 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(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, const void *daddr,
			 const 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("arcnet loaded.\n");

#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))
static void arcnet_dump_packet(struct net_device *dev, int bufnum,
			       char *desc, int take_arcnet_lock)
{
	struct arcnet_local *lp = 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");

}

#else

#define arcnet_dump_packet(dev, bufnum, desc,take_arcnet_lock) do { } while (0)

#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 = 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+1) % 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 = 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+1) % 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;
}

static const struct header_ops arcnet_header_ops = {
	.create = arcnet_header,
	.rebuild = arcnet_rebuild_header,
};


/* Setup a struct device for ARCnet. */
static void arcdev_setup(struct net_device *dev)
{
	dev->type = ARPHRD_ARCNET;
	dev->header_ops = &arcnet_header_ops;
	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;
}

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)