scc.c

用于底层开发的TCPIP协议栈源代码

	case CL_SERIAL_LINE:
	case CL_KISS:
		free(scc->fifo.buf);
	default:
		break;
	}
	free(scc);
	Sccchan[ifp->dev] = NULL;
	restore(i_state);
	return 0;
}

/* de-activate SCC driver on program exit */
void
sccstop()
{
	if(Sccinfo.init){			/* was it initialized? */
		maskoff(Sccinfo.ivec);		/* disable the interrupt */
		setirq(Sccinfo.ivec,Orgivec);	/* restore original interrupt vector */
	}
}

/* perform ioctl on SCC (async) channel
 * this is used for SLIP mode only, and will read/set the line speed
 */
static int32
scc_aioctl(ifp,cmd,set,val)
struct iface *ifp;
int cmd;
int set;
int32 val;
{
	struct sccchan *scc;
	unsigned int brgrate;

	scc = Sccchan[ifp->dev];

	switch(cmd){
	case PARAM_SPEED:
		if(set){
			brgrate = scc_speed(scc,16,val);
			scc->speed = Sccinfo.clk / (32L * (brgrate + 2));
		}
		return scc->speed;
	}
	return 0;
}

/* perform ioctl on SCC (sdlc) channel
 * this is used for AX.25 mode only, and will set the "kiss" parameters
 */
static int32
scc_sioctl(ifp,cmd,set,val)
struct iface *ifp;
int cmd;
int set;
int32 val;
{
	struct sccchan *scc;
	unsigned int brgrate;
	int i_state;
	
	scc = Sccchan[ifp->dev];

	switch(cmd){
	case PARAM_SPEED:
		if(set){
			if(val == 0)
				scc->extclock = 1;
			else {
			    brgrate = scc_speed(scc,32,val);/* init SCC speed */
			    scc->speed = Sccinfo.clk / (64L * (brgrate + 2));/* calc real speed */
			}
		}
		return scc->speed;
	case PARAM_TXDELAY:
		if(set)
			scc->a.txdelay = val;
		return scc->a.txdelay;
	case PARAM_PERSIST:
		if(set)
			scc->a.persist = val;
		return scc->a.persist;
	case PARAM_SLOTTIME:
		if(set)
			scc->a.slottime = val;
		return scc->a.slottime;
	case PARAM_TXTAIL:
		if(set)
			scc->a.tailtime = val;
		return scc->a.tailtime;
	case PARAM_FULLDUP:
		if(set)
			scc->a.fulldup = val;
		return scc->a.fulldup;
	case PARAM_WAIT:
		if(set)
			scc->a.waittime = val;
		return scc->a.waittime;
	case PARAM_MAXKEY:
		if(set)
			scc->a.maxkeyup = val;
		return scc->a.maxkeyup;
	case PARAM_MIN:
		if(set)
			scc->a.mintime = val;
		return scc->a.mintime;
	case PARAM_IDLE:
		if(set)
			scc->a.idletime = val;
		return scc->a.idletime;
	case PARAM_DTR:
		if(set){
			if(val)
				scc->wreg[R5] |= DTR;
			else
				scc->wreg[R5] &= ~DTR;

			i_state = dirps();
			if(scc->a.tstate == IDLE && scc->timercount == 0)
				scc->timercount = 1;	/* force an update */
			restore(i_state);
		}
		return (scc->wreg[R5] & DTR) ? 1 : 0;
	case PARAM_GROUP:
		if(set)
			scc->group = val;
		return scc->group;
	}
	return -1;
}

/* start SCC transmitter when it is idle (SLIP/KISS mode only) */
static void
scc_sstart(scc)
register struct sccchan *scc;
{
	if(scc->tbp != NULL ||	/* busy */
	 scc->sndq == NULL)	/* no work */
		return;

	scc->tbp = dequeue(&scc->sndq);
	WRREG(scc->data,FR_END);
}

/* show SCC status */
int
dosccstat()
{
	register struct sccchan *scc;
	int i;

	if(!Sccinfo.init){
		printf("SCC driver not initialized\n");
		return 0;
	}
	printf("Ch Iface    Sent   Rcvd   Error Space Overr   Rxints   Txints   Exints   Spints\n");

	for(i = 0; i <= Sccinfo.maxchan; i++){
		if((scc = Sccchan[i]) == NULL)
			continue;

		if(scc->int_receive == scc_asyrx)
			printf("%2d %-6s  ** asynch ** %7lu %5u %5u %8lu %8lu %8lu %8lu\n",i,scc->iface->name,
			    scc->rxerrs,scc->nospace,scc->rovers,
			    scc->rxints,scc->txints,scc->exints,scc->spints);
		else
			printf("%2d %-6s %6lu %6lu %7lu %5u %5u %8lu %8lu %8lu %8lu\n",i,scc->iface->name,
			    scc->enqueued,scc->rxframes,scc->rxerrs,scc->nospace,scc->rovers,
			    scc->rxints,scc->txints,scc->exints,scc->spints);
	}
	return 0;
}

/* send raw frame to SCC. used for AX.25 */
static int
scc_raw(
struct iface *ifp,
struct mbuf **bpp
){
	struct sccchan *scc;
	int i_state;

	dump(ifp,IF_TRACE_OUT,*bpp);
	ifp->rawsndcnt++;
	ifp->lastsent = secclock();

	scc = Sccchan[ifp->dev];

	if (scc->tx_inhibit){		/* transmitter inhibit */
		free_p(bpp);
		return -1;
    }

	enqueue(&scc->sndq,bpp);		/* enqueue packet */
	scc->enqueued++;

	i_state = dirps();

	if(scc->a.tstate == IDLE){	/* when transmitter is idle */
		scc->a.tstate = DEFER;	/* start the key-up sequence */
		scc->a.maxdefer = TPS * scc->a.idletime /
			scc->a.slottime;
		scc->timercount = scc->a.waittime;
	}
	restore(i_state);
	return 0;
}

static int
scc_send(
int dev,
struct mbuf **bpp
){
	struct sccchan *scc;

	scc = Sccchan[dev];
	enqueue(&scc->sndq,bpp);

	if(scc->tbp == NULL)
		scc_sstart(scc);
	return(0);
}

/* initialize interface for AX.25 use */
static int
scc_call(ifp,call)
register struct iface *ifp;
char *call;
{
	uint8 out[AXALEN];

	ifp->hwaddr = mallocw(AXALEN);
	if(setcall(out,call) == 0)
		memcpy(ifp->hwaddr,out,AXALEN);
	else
		memcpy(ifp->hwaddr,Mycall,AXALEN);
	return 0;
}

/* Interrupt handlers for asynchronous modes (kiss, slip) */

/* Transmitter interrupt handler */
/* This routine sends data from mbufs in SLIP format */
static void
scc_asytx(scc)
register struct sccchan *scc;
{
	register struct mbuf *bp;

	scc->txints++;

	if(scc->txchar != 0){		/* a character pending for transmit? */
		WRREG(scc->data,scc->txchar);	/* send it now */
		scc->txchar = 0;		/* next time, ignore it */
		return;
	}

	if(scc->tbp == NULL){	/* nothing to send? */
		if((scc->tbp = scc->sndq) != NULL){ /* dequeue next frame */
			scc->sndq = scc->sndq->anext;
			WRREG(scc->data,FR_END);	/* send FR_END to flush line garbage */
		} else {
			WRREG(scc->ctrl,RES_Tx_P);	/* else only reset pending int */
		}
		return;
	}
	while ((bp = scc->tbp)->cnt == 0){ /* nothing left in this mbuf? */
		bp = bp->next;			/* save link to next */

		free_mbuf(&scc->tbp);

		if((scc->tbp = bp) == NULL){ /* see if more mbufs follow */
			WRREG(scc->data,FR_END);	/* frame complete, send FR_END */
			return;
		}
	}
	/* now bp = scc->tbp (either from while or from if stmt above) */

	WRREG(scc->data,*(bp->data));	/* just send the character */
	bp->cnt--;				/* decrease mbuf byte count */
	bp->data++;				/* and increment the data pointer */
}

/* External/Status interrupt handler */
static void
scc_asyex(scc)
register struct sccchan *scc;
{
	register unsigned char status,changes;

	scc->exints++;
	status = RDREG(scc->ctrl);
	changes = status ^ scc->status;

	if(changes & BRK_ABRT){		/* BREAK? */
		if((status & BRK_ABRT) == 0)	/* BREAK now over? */
			VOID(RDREG(scc->data));	/* read the NUL character */
	}
	scc->status = status;
	WRREG(scc->ctrl,RES_EXT_INT);
}

/* Receiver interrupt handler under NOS.
 * Since the higher serial protocol routines are all written to work
 * well with the routines in 8250.c, it makes sense to handle
 * asynch i/o with the 8530 in a similar manner. Therefore, these
 * routines are as close to their counterparts in 8250.c as possible.
 */
 
static void
scc_asyrx(scc)
register struct sccchan *scc;
{
	register struct fifo *fp;
	char c;

	scc->rxints++;

	fp = &(scc->fifo);
	do {
		c = RDREG(scc->data);
		if(fp->cnt != fp->bufsize){
			*fp->wp++ = c;
			if(fp->wp >= &fp->buf[fp->bufsize])
				fp->wp = fp->buf;
			fp->cnt++;
		} else
			scc->nospace++;
	} while(RDREG(scc->ctrl) & Rx_CH_AV);
	ksignal(fp,1);	/* eventually move this to timer routine */
}

/* Blocking read from asynch input.
 * Essentially the same as get_asy() in 8250.c
 * See comments in asyrxint().
 */
static int
get_scc(dev)
int dev;
{
	register struct fifo *fp;
	uint8 c;
	int tmp;
	int i_state;

	fp = &(Sccchan[dev]->fifo);

	for(;;){
		i_state = dirps();
		tmp = fp->cnt;
		if(tmp != 0){
			fp->cnt--;
			restore(i_state);
			break;
		}
		restore(i_state);
		kwait(fp);
	}
	c = *fp->rp++;
	if(fp->rp >= &fp->buf[fp->bufsize])
		fp->rp = fp->buf;

	return c;
}

int
scc_frameup(dev)
int dev;
{
	Sccchan[dev]->rxframes++;
	return 0;
}

/* Receive Special Condition interrupt handler */
static void
scc_asysp(scc)
register struct sccchan *scc;
{
	register unsigned char status;

	scc->spints++;

	status = rd(scc,R1);		/* read receiver status */
	VOID(RDREG(scc->data));		/* flush offending character */

	if(status & (CRC_ERR | Rx_OVR))		/* did a framing error or overrun occur ? */
		scc->rovers++;			/* report as overrun */