sbni.c

linux-2.6.15.6

	if( nl->state & FL_SLAVE )
		spin_unlock( &((struct net_local *) nl->master->priv)->lock );
#endif
}


/*
 * Routine returns 1 if it need to acknoweledge received frame.
 * Empty frame received without errors won't be acknoweledged.
 */

static int
recv_frame( struct net_device  *dev )
{
	struct net_local  *nl   = (struct net_local *) dev->priv;
	unsigned long  ioaddr	= dev->base_addr;

	u32  crc = CRC32_INITIAL;

	unsigned  framelen, frameno, ack;
	unsigned  is_first, frame_ok;

	if( check_fhdr( ioaddr, &framelen, &frameno, &ack, &is_first, &crc ) ) {
		frame_ok = framelen > 4
			?  upload_data( dev, framelen, frameno, is_first, crc )
			:  skip_tail( ioaddr, framelen, crc );
		if( frame_ok )
			interpret_ack( dev, ack );
	} else
		frame_ok = 0;

	outb( inb( ioaddr + CSR0 ) ^ CT_ZER, ioaddr + CSR0 );
	if( frame_ok ) {
		nl->state |= FL_PREV_OK;
		if( framelen > 4 )
			nl->in_stats.all_rx_number++;
	} else
		nl->state &= ~FL_PREV_OK,
		change_level( dev ),
		nl->in_stats.all_rx_number++,
		nl->in_stats.bad_rx_number++;

	return  !frame_ok  ||  framelen > 4;
}


static void
send_frame( struct net_device  *dev )
{
	struct net_local  *nl    = (struct net_local *) dev->priv;

	u32  crc = CRC32_INITIAL;

	if( nl->state & FL_NEED_RESEND ) {

		/* if frame was sended but not ACK'ed - resend it */
		if( nl->trans_errors ) {
			--nl->trans_errors;
			if( nl->framelen != 0 )
				nl->in_stats.resend_tx_number++;
		} else {
			/* cannot xmit with many attempts */
#ifdef CONFIG_SBNI_MULTILINE
			if( (nl->state & FL_SLAVE)  ||  nl->link )
#endif
			nl->state |= FL_LINE_DOWN;
			drop_xmit_queue( dev );
			goto  do_send;
		}
	} else
		nl->trans_errors = TR_ERROR_COUNT;

	send_frame_header( dev, &crc );
	nl->state |= FL_NEED_RESEND;
	/*
	 * FL_NEED_RESEND will be cleared after ACK, but if empty
	 * frame sended then in prepare_to_send next frame
	 */


	if( nl->framelen ) {
		download_data( dev, &crc );
		nl->in_stats.all_tx_number++;
		nl->state |= FL_WAIT_ACK;
	}

	outsb( dev->base_addr + DAT, (u8 *)&crc, sizeof crc );

do_send:
	outb( inb( dev->base_addr + CSR0 ) & ~TR_REQ, dev->base_addr + CSR0 );

	if( nl->tx_frameno )
		/* next frame exists - we request card to send it */
		outb( inb( dev->base_addr + CSR0 ) | TR_REQ,
		      dev->base_addr + CSR0 );
}


/*
 * Write the frame data into adapter's buffer memory, and calculate CRC.
 * Do padding if necessary.
 */

static void
download_data( struct net_device  *dev,  u32  *crc_p )
{
	struct net_local  *nl    = (struct net_local *) dev->priv;
	struct sk_buff    *skb	 = nl->tx_buf_p;

	unsigned  len = min_t(unsigned int, skb->len - nl->outpos, nl->framelen);

	outsb( dev->base_addr + DAT, skb->data + nl->outpos, len );
	*crc_p = calc_crc32( *crc_p, skb->data + nl->outpos, len );

	/* if packet too short we should write some more bytes to pad */
	for( len = nl->framelen - len;  len--; )
		outb( 0, dev->base_addr + DAT ),
		*crc_p = CRC32( 0, *crc_p );
}


static int
upload_data( struct net_device  *dev,  unsigned  framelen,  unsigned  frameno,
	     unsigned  is_first,  u32  crc )
{
	struct net_local  *nl = (struct net_local *) dev->priv;

	int  frame_ok;

	if( is_first )
		nl->wait_frameno = frameno,
		nl->inppos = 0;

	if( nl->wait_frameno == frameno ) {

		if( nl->inppos + framelen  <=  ETHER_MAX_LEN )
			frame_ok = append_frame_to_pkt( dev, framelen, crc );

		/*
		 * if CRC is right but framelen incorrect then transmitter
		 * error was occurred... drop entire packet
		 */
		else if( (frame_ok = skip_tail( dev->base_addr, framelen, crc ))
			 != 0 )
			nl->wait_frameno = 0,
			nl->inppos = 0,
#ifdef CONFIG_SBNI_MULTILINE
			((struct net_local *) nl->master->priv)
				->stats.rx_errors++,
			((struct net_local *) nl->master->priv)
				->stats.rx_missed_errors++;
#else
			nl->stats.rx_errors++,
			nl->stats.rx_missed_errors++;
#endif
			/* now skip all frames until is_first != 0 */
	} else
		frame_ok = skip_tail( dev->base_addr, framelen, crc );

	if( is_first  &&  !frame_ok )
		/*
		 * Frame has been broken, but we had already stored
		 * is_first... Drop entire packet.
		 */
		nl->wait_frameno = 0,
#ifdef CONFIG_SBNI_MULTILINE
		((struct net_local *) nl->master->priv)->stats.rx_errors++,
		((struct net_local *) nl->master->priv)->stats.rx_crc_errors++;
#else
		nl->stats.rx_errors++,
		nl->stats.rx_crc_errors++;
#endif

	return  frame_ok;
}


static __inline void
send_complete( struct net_local  *nl )
{
#ifdef CONFIG_SBNI_MULTILINE
	((struct net_local *) nl->master->priv)->stats.tx_packets++;
	((struct net_local *) nl->master->priv)->stats.tx_bytes
		+= nl->tx_buf_p->len;
#else
	nl->stats.tx_packets++;
	nl->stats.tx_bytes += nl->tx_buf_p->len;
#endif
	dev_kfree_skb_irq( nl->tx_buf_p );

	nl->tx_buf_p = NULL;

	nl->outpos = 0;
	nl->state &= ~(FL_WAIT_ACK | FL_NEED_RESEND);
	nl->framelen   = 0;
}


static void
interpret_ack( struct net_device  *dev,  unsigned  ack )
{
	struct net_local  *nl = (struct net_local *) dev->priv;

	if( ack == FRAME_SENT_OK ) {
		nl->state &= ~FL_NEED_RESEND;

		if( nl->state & FL_WAIT_ACK ) {
			nl->outpos += nl->framelen;

			if( --nl->tx_frameno )
				nl->framelen = min_t(unsigned int,
						   nl->maxframe,
						   nl->tx_buf_p->len - nl->outpos);
			else
				send_complete( nl ),
#ifdef CONFIG_SBNI_MULTILINE
				netif_wake_queue( nl->master );
#else
				netif_wake_queue( dev );
#endif
		}
	}

	nl->state &= ~FL_WAIT_ACK;
}


/*
 * Glue received frame with previous fragments of packet.
 * Indicate packet when last frame would be accepted.
 */

static int
append_frame_to_pkt( struct net_device  *dev,  unsigned  framelen,  u32  crc )
{
	struct net_local  *nl = (struct net_local *) dev->priv;

	u8  *p;

	if( nl->inppos + framelen  >  ETHER_MAX_LEN )
		return  0;

	if( !nl->rx_buf_p  &&  !(nl->rx_buf_p = get_rx_buf( dev )) )
		return  0;

	p = nl->rx_buf_p->data + nl->inppos;
	insb( dev->base_addr + DAT, p, framelen );
	if( calc_crc32( crc, p, framelen ) != CRC32_REMAINDER )
		return  0;

	nl->inppos += framelen - 4;
	if( --nl->wait_frameno == 0 )		/* last frame received */
		indicate_pkt( dev );

	return  1;
}


/*
 * Prepare to start output on adapter.
 * Transmitter will be actually activated when marker is accepted.
 */

static void
prepare_to_send( struct sk_buff  *skb,  struct net_device  *dev )
{
	struct net_local  *nl = (struct net_local *) dev->priv;

	unsigned int  len;

	/* nl->tx_buf_p == NULL here! */
	if( nl->tx_buf_p )
		printk( KERN_ERR "%s: memory leak!\n", dev->name );

	nl->outpos = 0;
	nl->state &= ~(FL_WAIT_ACK | FL_NEED_RESEND);

	len = skb->len;
	if( len < SBNI_MIN_LEN )
		len = SBNI_MIN_LEN;

	nl->tx_buf_p	= skb;
	nl->tx_frameno	= (len + nl->maxframe - 1) / nl->maxframe;
	nl->framelen	= len < nl->maxframe  ?  len  :  nl->maxframe;

	outb( inb( dev->base_addr + CSR0 ) | TR_REQ,  dev->base_addr + CSR0 );
#ifdef CONFIG_SBNI_MULTILINE
	nl->master->trans_start = jiffies;
#else
	dev->trans_start = jiffies;
#endif
}


static void
drop_xmit_queue( struct net_device  *dev )
{
	struct net_local  *nl = (struct net_local *) dev->priv;

	if( nl->tx_buf_p )
		dev_kfree_skb_any( nl->tx_buf_p ),
		nl->tx_buf_p = NULL,
#ifdef CONFIG_SBNI_MULTILINE
		((struct net_local *) nl->master->priv)
			->stats.tx_errors++,
		((struct net_local *) nl->master->priv)
			->stats.tx_carrier_errors++;
#else
		nl->stats.tx_errors++,
		nl->stats.tx_carrier_errors++;
#endif

	nl->tx_frameno	= 0;
	nl->framelen	= 0;
	nl->outpos	= 0;
	nl->state &= ~(FL_WAIT_ACK | FL_NEED_RESEND);
#ifdef CONFIG_SBNI_MULTILINE
	netif_start_queue( nl->master );
	nl->master->trans_start = jiffies;
#else
	netif_start_queue( dev );
	dev->trans_start = jiffies;
#endif
}


static void
send_frame_header( struct net_device  *dev,  u32  *crc_p )
{
	struct net_local  *nl  = (struct net_local *) dev->priv;

	u32  crc = *crc_p;
	u32  len_field = nl->framelen + 6;	/* CRC + frameno + reserved */
	u8   value;

	if( nl->state & FL_NEED_RESEND )
		len_field |= FRAME_RETRY;	/* non-first attempt... */

	if( nl->outpos == 0 )
		len_field |= FRAME_FIRST;

	len_field |= (nl->state & FL_PREV_OK) ? FRAME_SENT_OK : FRAME_SENT_BAD;
	outb( SBNI_SIG, dev->base_addr + DAT );

	value = (u8) len_field;
	outb( value, dev->base_addr + DAT );
	crc = CRC32( value, crc );
	value = (u8) (len_field >> 8);
	outb( value, dev->base_addr + DAT );
	crc = CRC32( value, crc );

	outb( nl->tx_frameno, dev->base_addr + DAT );
	crc = CRC32( nl->tx_frameno, crc );
	outb( 0, dev->base_addr + DAT );
	crc = CRC32( 0, crc );
	*crc_p = crc;
}


/*
 * if frame tail not needed (incorrect number or received twice),
 * it won't store, but CRC will be calculated
 */

static int
skip_tail( unsigned int  ioaddr,  unsigned int  tail_len,  u32 crc )
{
	while( tail_len-- )
		crc = CRC32( inb( ioaddr + DAT ), crc );

	return  crc == CRC32_REMAINDER;
}


/*
 * Preliminary checks if frame header is correct, calculates its CRC
 * and split it to simple fields
 */

static int
check_fhdr( u32  ioaddr,  u32  *framelen,  u32  *frameno,  u32  *ack,
	    u32  *is_first,  u32  *crc_p )
{
	u32  crc = *crc_p;
	u8   value;

	if( inb( ioaddr + DAT ) != SBNI_SIG )
		return  0;

	value = inb( ioaddr + DAT );
	*framelen = (u32)value;
	crc = CRC32( value, crc );
	value = inb( ioaddr + DAT );
	*framelen |= ((u32)value) << 8;
	crc = CRC32( value, crc );

	*ack = *framelen & FRAME_ACK_MASK;
	*is_first = (*framelen & FRAME_FIRST) != 0;

	if( (*framelen &= FRAME_LEN_MASK) < 6
	    ||  *framelen > SBNI_MAX_FRAME - 3 )
		return  0;

	value = inb( ioaddr + DAT );
	*frameno = (u32)value;
	crc = CRC32( value, crc );

	crc = CRC32( inb( ioaddr + DAT ), crc );	/* reserved byte */
	*framelen -= 2;

	*crc_p = crc;
	return  1;
}


static struct sk_buff *
get_rx_buf( struct net_device  *dev )
{
	/* +2 is to compensate for the alignment fixup below */
	struct sk_buff  *skb = dev_alloc_skb( ETHER_MAX_LEN + 2 );
	if( !skb )
		return  NULL;

#ifdef CONFIG_SBNI_MULTILINE
	skb->dev = ((struct net_local *) dev->priv)->master;
#else
	skb->dev = dev;
#endif
	skb_reserve( skb, 2 );		/* Align IP on longword boundaries */
	return  skb;
}


static void
indicate_pkt( struct net_device  *dev )
{
	struct net_local  *nl  = (struct net_local *) dev->priv;
	struct sk_buff    *skb = nl->rx_buf_p;

	skb_put( skb, nl->inppos );

#ifdef CONFIG_SBNI_MULTILINE
	skb->protocol = eth_type_trans( skb, nl->master );
	netif_rx( skb );
	dev->last_rx = jiffies;
	++((struct net_local *) nl->master->priv)->stats.rx_packets;
	((struct net_local *) nl->master->priv)->stats.rx_bytes += nl->inppos;
#else
	skb->protocol = eth_type_trans( skb, dev );
	netif_rx( skb );
	dev->last_rx = jiffies;
	++nl->stats.rx_packets;
	nl->stats.rx_bytes += nl->inppos;
#endif
	nl->rx_buf_p = NULL;	/* protocol driver will clear this sk_buff */
}


/* -------------------------------------------------------------------------- */

/*
 * Routine checks periodically wire activity and regenerates marker if
 * connect was inactive for a long time.
 */

static void
sbni_watchdog( unsigned long  arg )
{
	struct net_device  *dev = (struct net_device *) arg;
	struct net_local   *nl  = (struct net_local *) dev->priv;
	struct timer_list  *w   = &nl->watchdog; 
	unsigned long	   flags;
	unsigned char	   csr0;

	spin_lock_irqsave( &nl->lock, flags );

	csr0 = inb( dev->base_addr + CSR0 );
	if( csr0 & RC_CHK ) {

		if( nl->timer_ticks ) {
			if( csr0 & (RC_RDY | BU_EMP) )
				/* receiving not active */
				nl->timer_ticks--;
		} else {
			nl->in_stats.timeout_number++;
			if( nl->delta_rxl )
				timeout_change_level( dev );

			outb( *(u_char *)&nl->csr1 | PR_RES,
			      dev->base_addr + CSR1 );
			csr0 = inb( dev->base_addr + CSR0 );
		}
	} else
		nl->state &= ~FL_LINE_DOWN;

	outb( csr0 | RC_CHK, dev->base_addr + CSR0 ); 

	init_timer( w );
	w->expires	= jiffies + SBNI_TIMEOUT;
	w->data		= arg;
	w->function	= sbni_watchdog;
	add_timer( w );

	spin_unlock_irqrestore( &nl->lock, flags );
}


static unsigned char  rxl_tab[] = {
	0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x08,
	0x0a, 0x0c, 0x0f, 0x16, 0x18, 0x1a, 0x1c, 0x1f
};

#define SIZE_OF_TIMEOUT_RXL_TAB 4
static unsigned char  timeout_rxl_tab[] = {
	0x03, 0x05, 0x08, 0x0b
};

/* -------------------------------------------------------------------------- */

static void
card_start( struct net_device  *dev )
{
	struct net_local  *nl = (struct net_local *) dev->priv;

	nl->timer_ticks = CHANGE_LEVEL_START_TICKS;
	nl->state &= ~(FL_WAIT_ACK | FL_NEED_RESEND);
	nl->state |= FL_PREV_OK;

	nl->inppos = nl->outpos = 0;
	nl->wait_frameno = 0;
	nl->tx_frameno	 = 0;
	nl->framelen	 = 0;

	outb( *(u_char *)&nl->csr1 | PR_RES, dev->base_addr + CSR1 );
	outb( EN_INT, dev->base_addr + CSR0 );
}

/* -------------------------------------------------------------------------- */

/* Receive level auto-selection */

static void
change_level( struct net_device  *dev )
{
	struct net_local  *nl = (struct net_local *) dev->priv;

	if( nl->delta_rxl == 0 )	/* do not auto-negotiate RxL */
		return;

	if( nl->cur_rxl_index == 0 )
		nl->delta_rxl = 1;
	else if( nl->cur_rxl_index == 15 )
		nl->delta_rxl = -1;
	else if( nl->cur_rxl_rcvd < nl->prev_rxl_rcvd )
		nl->delta_rxl = -nl->delta_rxl;

	nl->csr1.rxl = rxl_tab[ nl->cur_rxl_index += nl->delta_rxl ];
	inb( dev->base_addr + CSR0 );	/* needs for PCI cards */
	outb( *(u8 *)&nl->csr1, dev->base_addr + CSR1 );

	nl->prev_rxl_rcvd = nl->cur_rxl_rcvd;
	nl->cur_rxl_rcvd  = 0;
}


static void
timeout_change_level( struct net_device  *dev )
{
	struct net_local  *nl = (struct net_local *) dev->priv;

	nl->cur_rxl_index = timeout_rxl_tab[ nl->timeout_rxl ];
	if( ++nl->timeout_rxl >= 4 )
		nl->timeout_rxl = 0;

	nl->csr1.rxl = rxl_tab[ nl->cur_rxl_index ];
	inb( dev->base_addr + CSR0 );
	outb( *(unsigned char *)&nl->csr1, dev->base_addr + CSR1 );

	nl->prev_rxl_rcvd = nl->cur_rxl_rcvd;