wavelan.c

这是一个同样来自贝尔实验室的和UNIX有着渊源的操作系统, 其简洁的设计和实现易于我们学习和理解

/*
	Lucent Wavelan IEEE 802.11 pcmcia.
	There is almost no documentation for the card.
	the driver is done using both the FreeBSD, Linux and
	original Plan 9 drivers as `documentation'.

	Has been used with the card plugged in during all up time.
	no cards removals/insertions yet.

	For known BUGS see the comments below. Besides,
	the driver keeps interrupts disabled for just too
	long. When it gets robust, locks should be revisited.

	BUGS: check endian, alignment and mem/io issues;
	      multicast;
	      receive watchdog interrupts.
	TODO: automatic power management;
	      improve locking.
 */
#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "io.h"
#include "../port/error.h"
#include "../port/netif.h"
#include "etherif.h"
#include "wavelan.h"

enum
{
	MSperTick=	50,	/* ms between ticks of kproc */
};

/*
 * When we're using a PCI device and memory-mapped I/O, 
 * the registers are spaced out as though each takes 32 bits,
 * even though they are only 16-bit registers.  Thus, 
 * ctlr->mmb[reg] is the right way to access register reg,
 * even though a priori you'd expect to use ctlr->mmb[reg/2].
 */
void
csr_outs(Ctlr *ctlr, int reg, ushort arg)
{
	if(ctlr->mmb)
		ctlr->mmb[reg] = arg;
	else
		outs(ctlr->iob+reg, arg);
}

ushort
csr_ins(Ctlr *ctlr, int reg)
{
	if(ctlr->mmb)
		return ctlr->mmb[reg];
	else
		return ins(ctlr->iob+reg);
}

static void
csr_ack(Ctlr *ctlr, int ev)
{
	csr_outs(ctlr, WR_EvAck, ev);
}

static void
csr_inss(Ctlr *ctlr, int reg, void *dat, int ndat)
{
	ushort *rp, *wp;

	if(ctlr->mmb){
		rp = &ctlr->mmb[reg];
		wp = dat;
		while(ndat-- > 0)
			*wp++ = *rp;
	}else
		inss(ctlr->iob+reg, dat, ndat);
}

static void
csr_outss(Ctlr *ctlr, int reg, void *dat, int ndat)
{
	ushort *rp, *wp;

	if(ctlr->mmb){
		rp = dat;
		wp = &ctlr->mmb[reg];
		while(ndat-- > 0)
			*wp = *rp++;
	}else
		outss(ctlr->iob+reg, dat, ndat);
}

// w_... routines do not ilock the Ctlr and should
// be called locked.

void
w_intdis(Ctlr* ctlr)
{
	csr_outs(ctlr, WR_IntEna, 0);
	csr_ack(ctlr, 0xffff);
}

static void
w_intena(Ctlr* ctlr)
{
	csr_outs(ctlr, WR_IntEna, WEvs);
}

int
w_cmd(Ctlr *ctlr, ushort cmd, ushort arg)
{
	int i, rc;

	for(i=0; i<WTmOut; i++)
		if((csr_ins(ctlr, WR_Cmd)&WCmdBusy) == 0)
			break;
	if(i==WTmOut){
		print("#l%d: issuing cmd %.4ux: %.4ux\n", ctlr->ctlrno, cmd, csr_ins(ctlr, WR_Cmd));
		return -1;
	}

	csr_outs(ctlr, WR_Parm0, arg);
	csr_outs(ctlr, WR_Cmd, cmd);

	for(i=0; i<WTmOut; i++)
		if(csr_ins(ctlr, WR_EvSts)&WCmdEv)
			break;
	if(i==WTmOut){
		/*
		 * WCmdIni can take a really long time.
		 */
		enum { IniTmOut = 2000 };
		for(i=0; i<IniTmOut; i++){
			if(csr_ins(ctlr, WR_EvSts)&WCmdEv)
				break;
			microdelay(100);
		}
		if(i < IniTmOut)
			if(0) print("#l%d: long cmd %.4ux %d\n", ctlr->ctlrno, cmd, i);
		if(i == IniTmOut){
			print("#l%d: execing cmd %.4ux: %.4ux\n", ctlr->ctlrno, cmd, csr_ins(ctlr, WR_EvSts));
			return -1;
		}
	}
	rc = csr_ins(ctlr, WR_Sts);
	csr_ack(ctlr, WCmdEv);

	if((rc&WCmdMsk) != (cmd&WCmdMsk)){
		print("#l%d: cmd %.4ux: status %.4ux\n", ctlr->ctlrno, cmd, rc);
		return -1;
	}
	if(rc&WResSts){
		/*
		 * Don't print; this happens on every WCmdAccWr for some reason.
		 */
		if(0) print("#l%d: cmd %.4ux: status %.4ux\n", ctlr->ctlrno, cmd, rc);
		return -1;
	}
	return 0;
}

static int
w_seek(Ctlr* ctlr, ushort id, ushort offset, int chan)
{
	int i, rc;
	static ushort sel[] = { WR_Sel0, WR_Sel1 };
	static ushort off[] = { WR_Off0, WR_Off1 };

	if(chan != 0 && chan != 1)
		panic("wavelan: bad chan\n");
	csr_outs(ctlr, sel[chan], id);
	csr_outs(ctlr, off[chan], offset);
	for (i=0; i<WTmOut; i++){
		rc = csr_ins(ctlr, off[chan]);
		if((rc & (WBusyOff|WErrOff)) == 0)
			return 0;
	}
	return -1;
}

int
w_inltv(Ctlr* ctlr, Wltv* ltv)
{
	int len;
	ushort code;

	if(w_cmd(ctlr, WCmdAccRd, ltv->type)){
		DEBUG("wavelan: access read failed\n");
		return -1;
	}
	if(w_seek(ctlr,ltv->type,0,1)){
		DEBUG("wavelan: seek failed\n");
		return -1;
	}
	len = csr_ins(ctlr, WR_Data1);
	if(len > ltv->len)
		return -1;
	ltv->len = len;
	if((code=csr_ins(ctlr, WR_Data1)) != ltv->type){
		USED(code);
		DEBUG("wavelan: type %x != code %x\n",ltv->type,code);
		return -1;
	}
	if(ltv->len > 0)
		csr_inss(ctlr, WR_Data1, &ltv->val, ltv->len-1);

	return 0;
}

static void
w_outltv(Ctlr* ctlr, Wltv* ltv)
{
	if(w_seek(ctlr,ltv->type, 0, 1))
		return;
	csr_outss(ctlr, WR_Data1, ltv, ltv->len+1);
	w_cmd(ctlr, WCmdAccWr, ltv->type);
}

void
ltv_outs(Ctlr* ctlr, int type, ushort val)
{
	Wltv ltv;

	ltv.len = 2;
	ltv.type = type;
	ltv.val = val;
	w_outltv(ctlr, &ltv);
}

int
ltv_ins(Ctlr* ctlr, int type)
{
	Wltv ltv;

	ltv.len = 2;
	ltv.type = type;
	ltv.val = 0;
	if(w_inltv(ctlr, &ltv))
		return -1;
	return ltv.val;
}

static void
ltv_outstr(Ctlr* ctlr, int type, char* val)
{
	Wltv ltv;
	int len;

	len = strlen(val);
	if(len > sizeof(ltv.s))
		len = sizeof(ltv.s);
	memset(&ltv, 0, sizeof(ltv));
	ltv.len = (sizeof(ltv.type)+sizeof(ltv.slen)+sizeof(ltv.s))/2;
	ltv.type = type;

//	This should be ltv.slen = len; according to Axel Belinfante
	ltv.slen = len;	

	strncpy(ltv.s, val, len);
	w_outltv(ctlr, &ltv);
}

static char Unkname[] = "who knows";
static char Nilname[] = "card does not tell";

static char*
ltv_inname(Ctlr* ctlr, int type)
{
	static Wltv ltv;
	int len;

	memset(&ltv,0,sizeof(ltv));
	ltv.len = WNameLen/2+2;
	ltv.type = type;
	if(w_inltv(ctlr, &ltv))
		return Unkname;
	len = ltv.slen;
	if(len == 0 || ltv.s[0] == 0)
		return Nilname;
	if(len >= sizeof ltv.s)
		len = sizeof ltv.s - 1;
	ltv.s[len] = '\0';
	return ltv.s;
}

static int
w_read(Ctlr* ctlr, int type, int off, void* buf, ulong len)
{
	if(w_seek(ctlr, type, off, 1)){
		DEBUG("wavelan: w_read: seek failed");
		return 0;
	}
	csr_inss(ctlr, WR_Data1, buf, len/2);

	return len;
}

static int
w_write(Ctlr* ctlr, int type, int off, void* buf, ulong len)
{
	int tries;

	for (tries=0; tries < WTmOut; tries++){
		if(w_seek(ctlr, type, off, 0)){
			DEBUG("wavelan: w_write: seek failed\n");
			return 0;
		}

		csr_outss(ctlr, WR_Data0, buf, len/2);

		csr_outs(ctlr, WR_Data0, 0xdead);
		csr_outs(ctlr, WR_Data0, 0xbeef);
		if(w_seek(ctlr, type, off + len, 0)){
			DEBUG("wavelan: write seek failed\n");
			return 0;
		}
		if(csr_ins(ctlr, WR_Data0) == 0xdead)
		if(csr_ins(ctlr, WR_Data0) == 0xbeef)
			return len;
		DEBUG("wavelan: Hermes bug byte.\n");
		return 0;
	}
	DEBUG("wavelan: tx timeout\n");
	return 0;
}

static int
w_alloc(Ctlr* ctlr, int len)
{
	int rc;
	int i,j;

	if(w_cmd(ctlr, WCmdMalloc, len)==0)
		for (i = 0; i<WTmOut; i++)
			if(csr_ins(ctlr, WR_EvSts) & WAllocEv){
				csr_ack(ctlr, WAllocEv);
				rc=csr_ins(ctlr, WR_Alloc);
				if(w_seek(ctlr, rc, 0, 0))
					return -1;
				len = len/2;
				for (j=0; j<len; j++)
					csr_outs(ctlr, WR_Data0, 0);
				return rc;
			}
	return -1;
}

static int
w_enable(Ether* ether)
{
	Wltv ltv;
	Ctlr* ctlr = (Ctlr*) ether->ctlr;

	if(!ctlr)
		return -1;

	w_intdis(ctlr);
	w_cmd(ctlr, WCmdDis, 0);
	w_intdis(ctlr);
	if(w_cmd(ctlr, WCmdIni, 0))
		return -1;
	w_intdis(ctlr);

	ltv_outs(ctlr, WTyp_Tick, 8);
	ltv_outs(ctlr, WTyp_MaxLen, ctlr->maxlen);
	ltv_outs(ctlr, WTyp_Ptype, ctlr->ptype);
 	ltv_outs(ctlr, WTyp_CreateIBSS, ctlr->createibss);
	ltv_outs(ctlr, WTyp_RtsThres, ctlr->rtsthres);
	ltv_outs(ctlr, WTyp_TxRate, ctlr->txrate);
	ltv_outs(ctlr, WTyp_ApDens, ctlr->apdensity);
	ltv_outs(ctlr, WTyp_PMWait, ctlr->pmwait);
	ltv_outs(ctlr, WTyp_PM, ctlr->pmena);
	if(*ctlr->netname)
		ltv_outstr(ctlr, WTyp_NetName, ctlr->netname);
	if(*ctlr->wantname)
		ltv_outstr(ctlr, WTyp_WantName, ctlr->wantname);
	ltv_outs(ctlr, WTyp_Chan, ctlr->chan);
	if(*ctlr->nodename)
		ltv_outstr(ctlr, WTyp_NodeName, ctlr->nodename);
	ltv.len = 4;
	ltv.type = WTyp_Mac;
	memmove(ltv.addr, ether->ea, Eaddrlen);
	w_outltv(ctlr, &ltv);

	ltv_outs(ctlr, WTyp_Prom, (ether->prom?1:0));

	if(ctlr->hascrypt && ctlr->crypt){
		ltv_outs(ctlr, WTyp_Crypt, ctlr->crypt);
		ltv_outs(ctlr, WTyp_TxKey, ctlr->txkey);
		w_outltv(ctlr, &ctlr->keys);
		ltv_outs(ctlr, WTyp_XClear, ctlr->xclear);
	}

	// BUG: set multicast addresses

	if(w_cmd(ctlr, WCmdEna, 0)){
		DEBUG("wavelan: Enable failed");
		return -1;
	}
	ctlr->txdid = w_alloc(ctlr, 1518 + sizeof(WFrame) + 8);
	ctlr->txmid = w_alloc(ctlr, 1518 + sizeof(WFrame) + 8);
	if(ctlr->txdid == -1 || ctlr->txmid == -1)
		DEBUG("wavelan: alloc failed");
	ctlr->txbusy = 0;
	w_intena(ctlr);
	return 0;
}

static void
w_rxdone(Ether* ether)
{
	Ctlr* ctlr = (Ctlr*) ether->ctlr;
	int len, sp;
	WFrame f;
	Block* bp=0;
	Etherpkt* ep;

	sp = csr_ins(ctlr, WR_RXId);
	len = w_read(ctlr, sp, 0, &f, sizeof(f));
	if(len == 0){
		DEBUG("wavelan: read frame error\n");
		goto rxerror;
	}
	if(f.sts&WF_Err){
		goto rxerror;
	}
	switch(f.sts){
	case WF_1042:
	case WF_Tunnel:
	case WF_WMP:
		len = f.dlen + WSnapHdrLen;
		bp = iallocb(ETHERHDRSIZE + len + 2);
		if(!bp)
			goto rxerror;
		ep = (Etherpkt*) bp->wp;
		memmove(ep->d, f.addr1, Eaddrlen);
		memmove(ep->s, f.addr2, Eaddrlen);
		memmove(ep->type,&f.type,2);
		bp->wp += ETHERHDRSIZE;
		if(w_read(ctlr, sp, WF_802_11_Off, bp->wp, len+2) == 0){
			DEBUG("wavelan: read 802.11 error\n");
			goto rxerror;
		}
		bp->wp = bp->rp+(ETHERHDRSIZE+f.dlen);
		break;
	default:
		len = ETHERHDRSIZE + f.dlen + 2;
		bp = iallocb(len);
		if(!bp)
			goto rxerror;
		if(w_read(ctlr, sp, WF_802_3_Off, bp->wp, len) == 0){
			DEBUG("wavelan: read 800.3 error\n");
			goto rxerror;
		}
		bp->wp += len;
	}

	ctlr->nrx++;
	etheriq(ether,bp,1);
	ctlr->signal = ((ctlr->signal*15)+((f.qinfo>>8) & 0xFF))/16;
	ctlr->noise = ((ctlr->noise*15)+(f.qinfo & 0xFF))/16;
	return;

rxerror:
	freeb(bp);
	ctlr->nrxerr++;
}

static void
w_txstart(Ether* ether)
{
	Etherpkt *pkt;
	Ctlr *ctlr;
	Block *bp;
	int len, off;

	if((ctlr = ether->ctlr) == nil || (ctlr->state & (Attached|Power)) != (Attached|Power) || ctlr->txbusy)
		return;

	if((bp = qget(ether->oq)) == nil)
		return;
	pkt = (Etherpkt*)bp->rp;

	//
	// If the packet header type field is > 1500 it is an IP or
	// ARP datagram, otherwise it is an 802.3 packet. See RFC1042.
	//
	memset(&ctlr->txf, 0, sizeof(ctlr->txf));
	if(((pkt->type[0]<<8)|pkt->type[1]) > 1500){
		ctlr->txf.framectl = WF_Data;
		memmove(ctlr->txf.addr1, pkt->d, Eaddrlen);
		memmove(ctlr->txf.addr2, pkt->s, Eaddrlen);
		memmove(ctlr->txf.dstaddr, pkt->d, Eaddrlen);
		memmove(ctlr->txf.srcaddr, pkt->s, Eaddrlen);
		memmove(&ctlr->txf.type, pkt->type, 2);
		bp->rp += ETHERHDRSIZE;
		len = BLEN(bp);
		off = WF_802_11_Off;
		ctlr->txf.dlen = len+ETHERHDRSIZE-WSnapHdrLen;
		hnputs((uchar*)&ctlr->txf.dat[0], WSnap0);
		hnputs((uchar*)&ctlr->txf.dat[1], WSnap1);
		hnputs((uchar*)&ctlr->txf.len, len+ETHERHDRSIZE-WSnapHdrLen);
	}
	else{
		len = BLEN(bp);
		off = WF_802_3_Off;
		ctlr->txf.dlen = len;
	}
	w_write(ctlr, ctlr->txdid, 0, &ctlr->txf, sizeof(ctlr->txf));
	w_write(ctlr, ctlr->txdid, off, bp->rp, len+2);

	if(w_cmd(ctlr, WCmdReclaim|WCmdTx, ctlr->txdid)){
		DEBUG("wavelan: transmit failed\n");
		ctlr->ntxerr++;
	}
	else{
		ctlr->txbusy = 1;
		ctlr->txtmout = 2;
	}
	freeb(bp);
}

static void
w_txdone(Ctlr* ctlr, int sts)
{
	ctlr->txbusy = 0;
	ctlr->txtmout = 0;
	if(sts & WTxErrEv)
		ctlr->ntxerr++;
	else
		ctlr->ntx++;
}

/* save the stats info in the ctlr struct */
static void
w_stats(Ctlr* ctlr, int len)
{
	int i, rc;
	ulong* p = (ulong*)&ctlr->WStats;
	ulong* pend = (ulong*)&ctlr->end;

	for (i = 0; i < len && p < pend; i++){
		rc = csr_ins(ctlr, WR_Data1);
		if(rc > 0xf000)
			rc = ~rc & 0xffff;
		p[i] += rc;
	}
}

/* send the base station scan info to any readers */
static void
w_scaninfo(Ether* ether, Ctlr *ctlr, int len)
{
	int i, j;
	Netfile **ep, *f, **fp;
	Block *bp;
	WScan *wsp;
	ushort *scanbuf;

	scanbuf = malloc(len*2);
	if(scanbuf == nil)
		return;
	
	for (i = 0; i < len ; i++)
		scanbuf[i] = csr_ins(ctlr, WR_Data1);

	/* calculate number of samples */
	len /= 25;
	if(len == 0)
		goto out;

	i = ether->scan;
	ep = &ether->f[Ntypes];
	for(fp = ether->f; fp < ep && i > 0; fp++){
		f = *fp;
		if(f == nil || f->scan == 0)
			continue;

		bp = iallocb(100*len);
		if(bp == nil)
			break;
		for(j = 0; j < len; j++){
			wsp = (WScan*)(&scanbuf[j*25]);
			if(wsp->ssid_len > 32)
				wsp->ssid_len = 32;
			bp->wp = (uchar*)seprint((char*)bp->wp, (char*)bp->lim,
				"ssid=%.*s;bssid=%E;signal=%d;noise=%d;chan=%d%s\n",
				wsp->ssid_len, wsp->ssid, wsp->bssid, wsp->signal,
				wsp->noise, wsp->chan, (wsp->capinfo&(1<<4))?";wep":"");
		}
		qpass(f->in, bp);
		i--;
	}
out:
	free(scanbuf);
}

static int
w_info(Ether *ether, Ctlr* ctlr)
{
	int sp;
	Wltv ltv;

	sp = csr_ins(ctlr, WR_InfoId);
	ltv.len = ltv.type = 0;
	w_read(ctlr, sp, 0, &ltv, 4);
	ltv.len--;
	switch(ltv.type){
	case WTyp_Stats:
		w_stats(ctlr, ltv.len);
		return 0;
	case WTyp_Scan:
		w_scaninfo(ether, ctlr, ltv.len);