sdla_ppp.c

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		ppp_error(card, err, mb);
	
	return err;
}

/*============================================================================
 * Disable communications.
 */
static int ppp_comm_disable(sdla_t *card)
{
	ppp_mbox_t *mb = card->mbox;
	int err;

	memset(&mb->cmd, 0, sizeof(ppp_cmd_t));
	mb->cmd.command = PPP_COMM_DISABLE;
	err = sdla_exec(mb) ? mb->cmd.result : CMD_TIMEOUT;
	if (err != CMD_OK) 
		ppp_error(card, err, mb);

	return err;
}

/*============================================================================
 * Get communications error statistics.
 */
static int ppp_get_err_stats(sdla_t *card)
{
	ppp_mbox_t *mb = card->mbox;
	int err;

	memset(&mb->cmd, 0, sizeof(ppp_cmd_t));
	mb->cmd.command = PPP_READ_ERROR_STATS;
	err = sdla_exec(mb) ? mb->cmd.result : CMD_TIMEOUT;
	
	if (err == CMD_OK) {
		
		ppp_err_stats_t* stats = (void*)mb->data;
		card->wandev.stats.rx_over_errors    = stats->rx_overrun;
		card->wandev.stats.rx_crc_errors     = stats->rx_bad_crc;
		card->wandev.stats.rx_missed_errors  = stats->rx_abort;
		card->wandev.stats.rx_length_errors  = stats->rx_lost;
		card->wandev.stats.tx_aborted_errors = stats->tx_abort;
	
	} else 
		ppp_error(card, err, mb);
	
	return err;
}

/*============================================================================
 * Send packet.
 *	Return:	0 - o.k.
 *		1 - no transmit buffers available
 */
static int ppp_send (sdla_t *card, void *data, unsigned len, unsigned proto)
{
	ppp_buf_ctl_t *txbuf = card->u.p.txbuf;

	if (txbuf->flag)
                return 1;
	
	sdla_poke(&card->hw, txbuf->buf.ptr, data, len);

	txbuf->length = len;		/* frame length */
	
	if (proto == htons(ETH_P_IPX))
		txbuf->proto = 0x01;	/* protocol ID */
	else
		txbuf->proto = 0x00;	/* protocol ID */
	
	txbuf->flag = 1;		/* start transmission */

	/* Update transmit buffer control fields */
	card->u.p.txbuf = ++txbuf;

	if ((void*)txbuf > card->u.p.txbuf_last)
		card->u.p.txbuf = card->u.p.txbuf_base;

	return 0;
}

/****** Firmware Error Handler **********************************************/

/*============================================================================
 * Firmware error handler.
 *	This routine is called whenever firmware command returns non-zero
 *	return code.
 *
 * Return zero if previous command has to be cancelled.
 */
static int ppp_error(sdla_t *card, int err, ppp_mbox_t *mb)
{
	unsigned cmd = mb->cmd.command;

	switch (err) {

		case CMD_TIMEOUT:
			printk(KERN_ERR "%s: command 0x%02X timed out!\n",
				card->devname, cmd);
			break;

		default:
			printk(KERN_INFO "%s: command 0x%02X returned 0x%02X!\n"
				, card->devname, cmd, err);
	}

	return 0;
}

/****** Interrupt Handlers **************************************************/

/*============================================================================
 * PPP interrupt service routine.
 */
STATIC void wpp_isr(sdla_t *card)
{
	ppp_flags_t *flags = card->flags;
	char *ptr = &flags->iflag;
	struct net_device *dev = card->wandev.dev;


	int i;

	card->in_isr = 1;
	
	++card->statistics.isr_entry;

	//FIXME: Do we need this
	card->force_enable_irq = 0;

	if(card->hw.type != SDLA_S514){
		if (test_and_set_bit(0, (void*)&card->wandev.critical)) {
        	
			++card->statistics.isr_already_critical;
			printk (KERN_INFO "%s: Critical while in ISR!\n",
					card->devname);
			card->in_isr = 0;
			return;
	
		}
	}

	card->buff_int_mode_unbusy = 0;

	switch (flags->iflag) {

		case PPP_INTR_RXRDY:	/* receive interrupt  0x01  (bit 0)*/
			++card->statistics.isr_rx;
			rx_intr(card);
			break;

		case PPP_INTR_TXRDY:	/* transmit interrupt  0x02 (bit 1)*/
			++card->statistics.isr_tx;
			flags->imask &= ~PPP_INTR_TXRDY;
			netif_wake_queue (dev);
			card->buff_int_mode_unbusy = 1;
			break;

		case PPP_INTR_CMD:      /* interface command completed */
			++Intr_test_counter;
			++card->statistics.isr_intr_test;
			break;

		case PPP_INTR_MODEM:    /* modem status change (DCD, CTS) 0x04 (bit 2)*/
		case PPP_INTR_DISC:  	/* Data link disconnected 0x10  (bit 4)*/	
		case PPP_INTR_OPEN:   	/* Data link open 0x20  (bit 5)*/
		case PPP_INTR_DROP_DTR:	/* DTR drop timeout expired  0x40 bit 6 */
			event_intr(card);
			break;
	
		case PPP_INTR_TIMER:
			timer_intr(card);
			break;	 

		default:	/* unexpected interrupt */
			++card->statistics.isr_spurious;
			printk(KERN_INFO "%s: spurious interrupt 0x%02X!\n", 
				card->devname, flags->iflag);
			printk(KERN_INFO "%s: ID Bytes = ",card->devname);
	 		for(i = 0; i < 8; i ++)
				printk(KERN_INFO "0x%02X ", *(ptr + 0x28 + i));
			printk(KERN_INFO "\n");	
	}
	
	card->in_isr = 0;
	flags->iflag = 0;
	card->wandev.critical = 0;

	if(card->buff_int_mode_unbusy)
		netif_wake_queue(dev);
}

/*============================================================================
 * Receive interrupt handler.
 */
static void rx_intr(sdla_t *card)
{
	ppp_buf_ctl_t *rxbuf = card->rxmb;
	struct net_device *dev = card->wandev.dev;
	ppp_private_area_t *ppp_priv_area;
	struct sk_buff *skb;
	unsigned len;
	void *buf;
	int i;
        ppp_flags_t *flags = card->flags;
        char *ptr = &flags->iflag;
	int udp_type;
	

	if (rxbuf->flag != 0x01) {

		printk(KERN_INFO 
			"%s: corrupted Rx buffer @ 0x%X, flag = 0x%02X!\n", 
			card->devname, (unsigned)rxbuf, rxbuf->flag);
	
		printk(KERN_INFO "%s: ID Bytes = ",card->devname);
	 	
		for(i = 0; i < 8; i ++)
			printk(KERN_INFO "0x%02X ", *(ptr + 0x28 + i));
		printk(KERN_INFO "\n");	
		
		++card->statistics.rx_intr_corrupt_rx_bfr;
		return;

	}

	if (dev && netif_running(dev)) {
	
		len  = rxbuf->length;
		ppp_priv_area = dev->priv;

		/* Allocate socket buffer */
		skb = dev_alloc_skb(len);

		if (skb != NULL) {
		
			/* Copy data to the socket buffer */
			unsigned addr = rxbuf->buf.ptr;

			if ((addr + len) > card->u.p.rx_top + 1) {
			
				unsigned tmp = card->u.p.rx_top - addr + 1;
				buf = skb_put(skb, tmp);
				sdla_peek(&card->hw, addr, buf, tmp);
				addr = card->u.p.rx_base;
				len -= tmp;
			}
			buf = skb_put(skb, len);
			sdla_peek(&card->hw, addr, buf, len);

			/* Decapsulate packet */
        		switch (rxbuf->proto) {
	
				case 0x00:
					skb->protocol = htons(ETH_P_IP);
					break;

				case 0x01:
					skb->protocol = htons(ETH_P_IPX);
					break;
			}

			udp_type = udp_pkt_type( skb, card );

			if (udp_type == UDP_PTPIPE_TYPE){

				/* Handle a UDP Request in Timer Interrupt */
				if(store_udp_mgmt_pkt(UDP_PKT_FRM_NETWORK, card, skb, dev,
                	              			ppp_priv_area)){
	               			flags->imask |= PPP_INTR_TIMER;
				}
				++ppp_priv_area->rx_intr_stat.rx_intr_PIPE_request;


			} else if (handle_IPXWAN(skb->data,card->devname, 
						 ppp_priv_area->enable_IPX, 
						 ppp_priv_area->network_number, 
						 skb->protocol)) {
			
				/* Handle an IPXWAN packet */
				if( ppp_priv_area->enable_IPX) {
					ppp_send(card, skb->data, skb->len, htons(ETH_P_IPX));
                        		dev_kfree_skb(skb);


				} else {
					++card->wandev.stats.rx_dropped;
				}
			} else {
				/* Pass data up the protocol stack */
	    			skb->dev = dev;
				skb->mac.raw  = skb->data;

			    	++card->wandev.stats.rx_packets;
				card->wandev.stats.rx_bytes += skb->len;
		    		++ppp_priv_area->rx_intr_stat.rx_intr_bfr_passed_to_stack;	
				netif_rx(skb);
			}

		} else {
		
			printk(KERN_INFO "%s: no socket buffers available!\n",
				card->devname);
			++card->wandev.stats.rx_dropped;
			++ppp_priv_area->rx_intr_stat.rx_intr_no_socket;
			
               		dev_kfree_skb(skb);
		}

	} else {
		++card->statistics.rx_intr_dev_not_started;
	}

	/* Release buffer element and calculate a pointer to the next one */
	rxbuf->flag = 0x00;
	card->rxmb = ++rxbuf;
	if ((void*)rxbuf > card->u.p.rxbuf_last)
		card->rxmb = card->u.p.rxbuf_base;
}


void event_intr (sdla_t *card)
{

 	struct net_device* dev = card->wandev.dev;
        ppp_private_area_t* ppp_priv_area = dev->priv;
	volatile ppp_flags_t *flags = card->flags;

	switch (flags->iflag){

		case PPP_INTR_MODEM:    /* modem status change (DCD, CTS) 0x04  (bit 2)*/
			printk (KERN_INFO "%s: Modem status: DCD=%s CTS=%s\n",
				card->devname, DCD(flags->mstatus), CTS(flags->mstatus));

			break;

		case PPP_INTR_DISC:  	/* Data link disconnected 0x10  (bit 4)*/	

			NEX_PRINTK (KERN_INFO "Data link disconnected intr Cause %X\n",
					       flags->disc_cause);

			if (flags->disc_cause &
				(PPP_LOCAL_TERMINATION | PPP_DCD_CTS_DROP |
				PPP_REMOTE_TERMINATION)) {
				if (card->u.p.ip_mode == WANOPT_PPP_PEER) { 
					Read_connection_info = 1;
					remove_route (card);
				}
				wanpipe_set_state(card, WAN_DISCONNECTED);
				show_disc_cause(card, flags->disc_cause);
				ppp_priv_area->timer_int_enabled |= 
						TMR_INT_ENABLED_PPP_EVENT;
				flags->imask |= PPP_INTR_TIMER;
			}
			break;

		case PPP_INTR_OPEN:   	/* Data link open 0x20  (bit 5)*/

			NEX_PRINTK (KERN_INFO "%s: PPP Link Open, LCP=%s IP=%s\n",
					card->devname,LCP(flags->lcp_state),
					IP(flags->ip_state));

			if (flags->lcp_state == 0x09 && 
                           (flags->ip_state == 0x09 || flags->ipx_state == 0x09)){
                                /* Initialize the polling timer and set the state
                                 * to WAN_CONNNECTED 
                                 */
                                card->state_tick = jiffies;
				wanpipe_set_state(card, WAN_CONNECTED);
				ppp_priv_area->timer_int_enabled |= 
						TMR_INT_ENABLED_PPP_EVENT;
				flags->imask |= PPP_INTR_TIMER;

			}
                   	break;

		case PPP_INTR_DROP_DTR:		/* DTR drop timeout expired  0x40 bit 6 */

			NEX_PRINTK(KERN_INFO "DTR Drop Timeout Interrrupt \n"); 
			if (card->u.p.ip_mode == WANOPT_PPP_PEER) { 
				Read_connection_info = 1;
				remove_route (card);
			}
			wanpipe_set_state(card, WAN_DISCONNECTED);
			show_disc_cause(card, flags->disc_cause);
			ppp_priv_area->timer_int_enabled |= 
						TMR_INT_ENABLED_PPP_EVENT;
			flags->imask |= PPP_INTR_TIMER;
			break;
		
		default:
			printk(KERN_INFO "%s: Error, Invalid PPP Event\n",card->devname);
	}
}



/* TIMER INTERRUPT */

void timer_intr (sdla_t *card)
{

        struct net_device* dev = card->wandev.dev;
        ppp_private_area_t* ppp_priv_area = dev->priv;
	ppp_flags_t *flags = card->flags;

	/* Update statistics */
	if (ppp_priv_area->timer_int_enabled & TMR_INT_ENABLED_UPDATE){
		ppp_get_err_stats(card);
                if(!(--ppp_priv_area->update_comms_stats)){
			ppp_priv_area->timer_int_enabled &= 
				~TMR_INT_ENABLED_UPDATE;
		}
	}

	/* PPIPEMON UDP request */

	if (ppp_priv_area->timer_int_enabled & TMR_INT_ENABLED_UDP){
		process_udp_mgmt_pkt(card,dev, ppp_priv_area);
		ppp_priv_area->timer_int_enabled &= ~TMR_INT_ENABLED_UDP;
	}


	/* PPP Event */
	if (ppp_priv_area->timer_int_enabled & TMR_INT_ENABLED_PPP_EVENT){

		if (card->wandev.state == WAN_DISCONNECTED){
			poll_disconnected(card);
		}

		/* If the state is CONNECTING, it means that communicatins were
	 	 * enabled. When the remote side enables its comminication we
	 	 * should get an interrupt PPP_INTR_OPEN, thus turn off polling 
		 */

		else if (card->wandev.state == WAN_CONNECTING){
			/* Turn off the timer interrupt */
			ppp_priv_area->timer_int_enabled &= ~TMR_INT_ENABLED_PPP_EVENT;
		}

		/* If state is connected and we are in PEER mode 
	 	 * poll for an IP address which will be provided by remote end.
	 	 */
		else if ((card->wandev.state == WAN_CONNECTED && 
		  	card->u.p.ip_mode == WANOPT_PPP_PEER) && 
		  	Read_connection_info){

			card->state_tick = jiffies;
			if (!read_connection_info (card)){
				card->poll = &process_route;
			}

		}else{
			/* If we are using Static IP,no need to poll for
			 * an IP address. 
		 	 */
			NEX_PRINTK(KERN_INFO "Turning off TIMER \n");
			ppp_priv_area->timer_int_enabled &= ~TMR_INT_ENABLED_PPP_EVENT;
		}	

	}/* End of PPP_EVENT */