scc.c

linux-2.4.29操作系统的源码

	grp1 = scc->kiss.group;
	
	for (k = 0; k < (Nchips * 2); k++)
	{
		scc2 = &SCC_Info[k];
		grp2 = scc2->kiss.group;
		
		if (scc2 == scc || !(scc2->dev && grp2))
			continue;
		
		if ((grp1 & 0x3f) == (grp2 & 0x3f))
		{
			if ( (grp1 & TXGROUP) && (scc2->wreg[R5] & RTS) )
				return 1;
			
			if ( (grp1 & RXGROUP) && scc2->dcd )
				return 1;
		}
	}
	return 0;
}

/* DWAIT and SLOTTIME expired
 *
 * fulldup == 0:  DCD is active or Rand > P-persistence: start t_busy timer
 *                else key trx and start txdelay
 * fulldup == 1:  key trx and start txdelay
 * fulldup == 2:  mintime expired, reset status or key trx and start txdelay
 */

static void t_dwait(unsigned long channel)
{
	struct scc_channel *scc = (struct scc_channel *) channel;
	
	if (scc->stat.tx_state == TXS_WAIT)	/* maxkeyup or idle timeout */
	{
		if (skb_queue_len(&scc->tx_queue) == 0)	/* nothing to send */
		{
			scc->stat.tx_state = TXS_IDLE;
			netif_wake_queue(scc->dev);	/* t_maxkeyup locked it. */
			return;
		}

		scc->stat.tx_state = TXS_BUSY;
	}

	if (scc->kiss.fulldup == KISS_DUPLEX_HALF)
	{
		Rand = Rand * 17 + 31;
		
		if (scc->dcd || (scc->kiss.persist) < Rand || (scc->kiss.group && is_grouped(scc)) )
		{
			scc_start_defer(scc);
			scc_start_tx_timer(scc, t_dwait, scc->kiss.slottime);
			return ;
		}
	}

	if ( !(scc->wreg[R5] & RTS) )
	{
		scc_key_trx(scc, TX_ON);
		scc_start_tx_timer(scc, t_txdelay, scc->kiss.txdelay);
	} else {
		scc_start_tx_timer(scc, t_txdelay, 0);
	}
}


/* TXDELAY expired
 *
 * kick transmission by a fake scc_txint(scc), start 'maxkeyup' watchdog.
 */

static void t_txdelay(unsigned long channel)
{
	struct scc_channel *scc = (struct scc_channel *) channel;

	scc_start_maxkeyup(scc);

	if (scc->tx_buff == NULL)
	{
		disable_irq(scc->irq);
		scc_txint(scc);	
		enable_irq(scc->irq);
	}
}
	

/* TAILTIME expired
 *
 * switch off transmitter. If we were stopped by Maxkeyup restart
 * transmission after 'mintime' seconds
 */

static void t_tail(unsigned long channel)
{
	struct scc_channel *scc = (struct scc_channel *) channel;
	unsigned long flags;
	
 	save_flags(flags);
 	cli();
 
 	del_timer(&scc->tx_wdog);	
 	scc_key_trx(scc, TX_OFF);

 	restore_flags(flags);

 	if (scc->stat.tx_state == TXS_TIMEOUT)		/* we had a timeout? */
 	{
 		scc->stat.tx_state = TXS_WAIT;

 		if (scc->kiss.mintime != TIMER_OFF)	/* try it again */
 			scc_start_tx_timer(scc, t_dwait, scc->kiss.mintime*100);
 		else
 			scc_start_tx_timer(scc, t_dwait, 0);
 		return;
 	}
 	
 	scc->stat.tx_state = TXS_IDLE;
	netif_wake_queue(scc->dev);
}


/* BUSY timeout
 *
 * throw away send buffers if DCD remains active too long.
 */

static void t_busy(unsigned long channel)
{
	struct scc_channel *scc = (struct scc_channel *) channel;

	del_timer(&scc->tx_t);
	netif_stop_queue(scc->dev);	/* don't pile on the wabbit! */

	scc_discard_buffers(scc);
	scc->stat.txerrs++;
	scc->stat.tx_state = TXS_IDLE;

	netif_wake_queue(scc->dev);	
}

/* MAXKEYUP timeout
 *
 * this is our watchdog.
 */

static void t_maxkeyup(unsigned long channel)
{
	struct scc_channel *scc = (struct scc_channel *) channel;
	unsigned long flags;

	save_flags(flags);
	cli();

	/* 
	 * let things settle down before we start to
	 * accept new data.
	 */

	netif_stop_queue(scc->dev);
	scc_discard_buffers(scc);

	del_timer(&scc->tx_t);

	cl(scc, R1, TxINT_ENAB);	/* force an ABORT, but don't */
	cl(scc, R15, TxUIE);		/* count it. */
	OutReg(scc->ctrl, R0, RES_Tx_P);

	restore_flags(flags);

	scc->stat.txerrs++;
	scc->stat.tx_state = TXS_TIMEOUT;
	scc_start_tx_timer(scc, t_tail, scc->kiss.tailtime);
}

/* IDLE timeout
 *
 * in fulldup mode 2 it keys down the transmitter after 'idle' seconds
 * of inactivity. We will not restart transmission before 'mintime'
 * expires.
 */

static void t_idle(unsigned long channel)
{
	struct scc_channel *scc = (struct scc_channel *) channel;
	
	del_timer(&scc->tx_wdog);

	scc_key_trx(scc, TX_OFF);

	if (scc->kiss.mintime != TIMER_OFF)
		scc_start_tx_timer(scc, t_dwait, scc->kiss.mintime*100);
	scc->stat.tx_state = TXS_WAIT;
}

static void scc_init_timer(struct scc_channel *scc)
{
	unsigned long flags;
	
	save_flags(flags); 
	cli();
	
	scc->stat.tx_state = TXS_IDLE;

	restore_flags(flags);
}


/* ******************************************************************** */
/* *			Set/get L1 parameters			      * */
/* ******************************************************************** */


/*
 * this will set the "hardware" parameters through KISS commands or ioctl()
 */

#define CAST(x) (unsigned long)(x)

static unsigned int scc_set_param(struct scc_channel *scc, unsigned int cmd, unsigned int arg)
{
	switch (cmd)
	{
		case PARAM_TXDELAY:	scc->kiss.txdelay=arg;		break;
		case PARAM_PERSIST:	scc->kiss.persist=arg;		break;
		case PARAM_SLOTTIME:	scc->kiss.slottime=arg;		break;
		case PARAM_TXTAIL:	scc->kiss.tailtime=arg;		break;
		case PARAM_FULLDUP:	scc->kiss.fulldup=arg;		break;
		case PARAM_DTR:		break; /* does someone need this? */
		case PARAM_GROUP:	scc->kiss.group=arg;		break;
		case PARAM_IDLE:	scc->kiss.idletime=arg;		break;
		case PARAM_MIN:		scc->kiss.mintime=arg;		break;
		case PARAM_MAXKEY:	scc->kiss.maxkeyup=arg;		break;
		case PARAM_WAIT:	scc->kiss.waittime=arg;		break;
		case PARAM_MAXDEFER:	scc->kiss.maxdefer=arg;		break;
		case PARAM_TX:		scc->kiss.tx_inhibit=arg;	break;

		case PARAM_SOFTDCD:	
			scc->kiss.softdcd=arg;
			if (arg)
			{
				or(scc, R15, SYNCIE);
				cl(scc, R15, DCDIE);
				start_hunt(scc);
			} else {
				or(scc, R15, DCDIE);
				cl(scc, R15, SYNCIE);
			}
			break;
				
		case PARAM_SPEED:
			if (arg < 256)
				scc->modem.speed=arg*100;
			else
				scc->modem.speed=arg;

			if (scc->stat.tx_state == 0)	/* only switch baudrate on rx... ;-) */
				set_speed(scc);
			break;
			
		case PARAM_RTS:	
			if ( !(scc->wreg[R5] & RTS) )
			{
				if (arg != TX_OFF)
					scc_key_trx(scc, TX_ON);
					scc_start_tx_timer(scc, t_txdelay, scc->kiss.txdelay);
			} else {
				if (arg == TX_OFF)
				{
					scc->stat.tx_state = TXS_BUSY;
					scc_start_tx_timer(scc, t_tail, scc->kiss.tailtime);
				}
			}
			break;
			
		case PARAM_HWEVENT:
			scc_notify(scc, scc->dcd? HWEV_DCD_ON:HWEV_DCD_OFF);
			break;

		default:		return -EINVAL;
	}
	
	return 0;
}


 
static unsigned long scc_get_param(struct scc_channel *scc, unsigned int cmd)
{
	switch (cmd)
	{
		case PARAM_TXDELAY:	return CAST(scc->kiss.txdelay);
		case PARAM_PERSIST:	return CAST(scc->kiss.persist);
		case PARAM_SLOTTIME:	return CAST(scc->kiss.slottime);
		case PARAM_TXTAIL:	return CAST(scc->kiss.tailtime);
		case PARAM_FULLDUP:	return CAST(scc->kiss.fulldup);
		case PARAM_SOFTDCD:	return CAST(scc->kiss.softdcd);
		case PARAM_DTR:		return CAST((scc->wreg[R5] & DTR)? 1:0);
		case PARAM_RTS:		return CAST((scc->wreg[R5] & RTS)? 1:0);
		case PARAM_SPEED:	return CAST(scc->modem.speed);
		case PARAM_GROUP:	return CAST(scc->kiss.group);
		case PARAM_IDLE:	return CAST(scc->kiss.idletime);
		case PARAM_MIN:		return CAST(scc->kiss.mintime);
		case PARAM_MAXKEY:	return CAST(scc->kiss.maxkeyup);
		case PARAM_WAIT:	return CAST(scc->kiss.waittime);
		case PARAM_MAXDEFER:	return CAST(scc->kiss.maxdefer);
		case PARAM_TX:		return CAST(scc->kiss.tx_inhibit);
		default:		return NO_SUCH_PARAM;
	}

}

#undef CAST

/* ******************************************************************* */
/* *			Send calibration pattern		     * */
/* ******************************************************************* */

static void scc_stop_calibrate(unsigned long channel)
{
	struct scc_channel *scc = (struct scc_channel *) channel;
	unsigned long flags;
	
	save_flags(flags);
	cli();

	del_timer(&scc->tx_wdog);
	scc_key_trx(scc, TX_OFF);
	wr(scc, R6, 0);
	wr(scc, R7, FLAG);
	Outb(scc->ctrl,RES_EXT_INT);	/* reset ext/status interrupts */
	Outb(scc->ctrl,RES_EXT_INT);

	netif_wake_queue(scc->dev);
	restore_flags(flags);
}


static void
scc_start_calibrate(struct scc_channel *scc, int duration, unsigned char pattern)
{
	unsigned long flags;
	
	save_flags(flags);
	cli();

	netif_stop_queue(scc->dev);
	scc_discard_buffers(scc);

	del_timer(&scc->tx_wdog);

	scc->tx_wdog.data = (unsigned long) scc;
	scc->tx_wdog.function = scc_stop_calibrate;
	scc->tx_wdog.expires = jiffies + HZ*duration;
	add_timer(&scc->tx_wdog);

	/* This doesn't seem to work. Why not? */	
	wr(scc, R6, 0);
	wr(scc, R7, pattern);

	/* 
	 * Don't know if this works. 
	 * Damn, where is my Z8530 programming manual...? 
	 */

	Outb(scc->ctrl,RES_EXT_INT);	/* reset ext/status interrupts */
	Outb(scc->ctrl,RES_EXT_INT);

	scc_key_trx(scc, TX_ON);
	restore_flags(flags);
}

/* ******************************************************************* */
/* *		Init channel structures, special HW, etc...	     * */
/* ******************************************************************* */

/*
 * Reset the Z8530s and setup special hardware
 */

static void z8530_init(void)
{
	struct scc_channel *scc;
	int chip, k;
	unsigned long flags;
	char *flag;


	printk(KERN_INFO "Init Z8530 driver: %u channels, IRQ", Nchips*2);
	
	flag=" ";
	for (k = 0; k < NR_IRQS; k++)
		if (Ivec[k].used) 
		{
			printk("%s%d", flag, k);
			flag=",";
		}
	printk("\n");


	/* reset and pre-init all chips in the system */
	for (chip = 0; chip < Nchips; chip++)
	{
		scc=&SCC_Info[2*chip];
		if (!scc->ctrl) continue;

		/* Special SCC cards */

		if(scc->brand & EAGLE)			/* this is an EAGLE card */
			Outb(scc->special,0x08);	/* enable interrupt on the board */
			
		if(scc->brand & (PC100 | PRIMUS))	/* this is a PC100/PRIMUS card */
			Outb(scc->special,scc->option);	/* set the MODEM mode (0x22) */

			
		/* Reset and pre-init Z8530 */

		save_flags(flags);
		cli();
		
		Outb(scc->ctrl, 0);
		OutReg(scc->ctrl,R9,FHWRES);		/* force hardware reset */
		udelay(100);				/* give it 'a bit' more time than required */
		wr(scc, R2, chip*16);			/* interrupt vector */
		wr(scc, R9, VIS);			/* vector includes status */
		
        	restore_flags(flags);
        }

 
	Driver_Initialized = 1;
}

/*
 * Allocate device structure, err, instance, and register driver
 */

static int scc_net_setup(struct scc_channel *scc, unsigned char *name, int addev)
{
	struct net_device *dev;

	if (dev_get(name))
	{
		printk(KERN_INFO "Z8530drv: device %s already exists.\n", name);
		return -EEXIST;
	}

	if ((scc->dev = (struct net_device *) kmalloc(sizeof(struct net_device), GFP_KERNEL)) == NULL)
		return -ENOMEM;

	dev = scc->dev;
	memset(dev, 0, sizeof(struct net_device));

	strcpy(dev->name, name);
	dev->priv = (void *) scc;
	dev->init = scc_net_init;

	if ((addev? register_netdevice(dev) : register_netdev(dev)) != 0) {
		kfree(dev);
                return -EIO;
        }

	SET_MODULE_OWNER(dev);
	return 0;
}



/* ******************************************************************** */
/* *			    Network driver methods		      * */
/* ******************************************************************** */

static unsigned char ax25_bcast[AX25_ADDR_LEN] =
{'Q' << 1, 'S' << 1, 'T' << 1, ' ' << 1, ' ' << 1, ' ' << 1, '0' << 1};
static unsigned char ax25_nocall[AX25_ADDR_LEN] =
{'L' << 1, 'I' << 1, 'N' << 1, 'U' << 1, 'X' << 1, ' ' << 1, '1' << 1};

/* ----> Initialize device <----- */

static int scc_net_init(struct net_device *dev)
{
	dev->tx_queue_len    = 16;	/* should be enough... */

	dev->open            = scc_net_open;
	dev->stop	     = scc_net_close;

	dev->hard_start_xmit = scc_net_tx;
	dev->hard_header     = ax25_encapsulate;
	dev->rebuild_header  = ax25_rebuild_header;
	dev->set_mac_address = scc_net_set_mac_address;
	dev->get_stats       = scc_net_get_stats;
	dev->do_ioctl        = scc_net_ioctl;
	dev->tx_timeout      = NULL;

	memcpy(dev->broadcast, ax25_bcast,  AX25_ADDR_LEN);
	memcpy(dev->dev_addr,  ax25_nocall, AX25_ADDR_LEN);
 
	dev->flags      = 0;

	dev->type = ARPHRD_AX25;
	dev->hard_header_len = AX25_MAX_HEADER_LEN + AX25_BPQ_HEADER_LEN;
	dev->mtu = AX25_DEF_PACLEN;
	dev->addr_len = AX25_ADDR_LEN;

	return 0;
}

/* ----> open network device <---- */

static int scc_net_open(struct net_device *dev)
{
	struct scc_channel *scc = (struct scc_channel *) dev->priv;

 	if (!scc->init)
		return -EINVAL;

	scc->tx_buff = NULL;
	skb_queue_head_init(&scc->tx_queue);
 
	init_channel(scc);

	netif_start_queue(dev);
	return 0;
}

/* ----> close network device <---- */

static int scc_net_close(struct net_device *dev)
{
	struct scc_channel *scc = (struct scc_channel *) dev->priv;
	unsigned long flags;

	netif_stop_queue(dev);

	save_flags(flags); 
	cli();
	
	Outb(scc->ctrl,0);		/* Make sure pointer is written */
	wr(scc,R1,0);			/* disable interrupts */
	wr(scc,R3,0);

	del_timer(&scc->tx_t);
	del_timer(&scc->tx_wdog);

	restore_flags(flags);