sb16: new approach, works in qemu

sys/src/9/pc/devfloppy.c

@@ -857,7 +857,7 @@ floppyxfer(FDrive *dp, int cmd, void *a, long off, long n)
 		dmaend(DMAchan);
 		nexterror();
 	}
-	dp->len = dmasetup(DMAchan, a, dp->len, cmd==Fread);
+	dp->len = dmasetup(DMAchan, a, dp->len, cmd==Fread ? DMAREAD : DMAWRITE);
 	if(dp->len < 0)
 		error(Eio);
 
@@ -999,7 +999,7 @@ floppyformat(FDrive *dp, Cmdbuf *cb)
 			dmaend(DMAchan);
 			nexterror();
 		}
-		if(dmasetup(DMAchan, buf, bp-buf, 0) < 0)
+		if(dmasetup(DMAchan, buf, bp-buf, DMAWRITE) < 0)
 			error(Eio);
 
 		/*

sys/src/9/pc/dma.c

@@ -18,7 +18,7 @@ struct DMAxfer
 	int	blen;		/* bounce buffer length */
 	void*	va;		/* virtual address destination/src */
 	long	len;		/* bytes to be transferred */
-	int	isread;
+	int	flags;
 };
 
 /*
@@ -81,7 +81,7 @@ _i8237alloc(void)
 	if(i8237dma > 2)
 		i8237dma = 2;
 
-	bva = xspanalloc(64*1024*i8237dma, BY2PG, 64*1024);
+	bva = xspanalloc(64*1024*i8237dma, 0, 64*1024);
 	if(bva == nil || PADDR(bva)+64*1024*i8237dma > 16*MB){
 		/*
 		 * This will panic with the current
@@ -137,11 +137,38 @@ dmainit(int chan, int maxtransfer)
 	xp->bpa = PADDR(xp->bva);
 	xp->blen = maxtransfer;
 	xp->len = 0;
-	xp->isread = 0;
+	xp->flags = 0;
 
 	return 0;
 }
 
+void*
+dmabva(int chan)
+{
+	DMA *dp;
+	DMAxfer *xp;
+
+	dp = &dma[(chan>>2)&1];
+	chan = chan & 3;
+	xp = &dp->x[chan];
+	return xp->bva;
+}
+
+int
+dmacount(int chan)
+{
+	int     retval;
+	DMA     *dp;
+ 
+	dp = &dma[(chan>>2)&1];
+	chan = chan & 3;
+	ilock(dp);
+	retval = inb(dp->count[chan]);
+	retval |= inb(dp->count[chan]) << 8;
+	iunlock(dp);
+	return ((retval<<dp->shift)+1) & 0xFFFF;
+}
+
 /*
  *  setup a dma transfer.  if the destination is not in kernel
  *  memory, allocate a page for the transfer.
@@ -153,7 +180,7 @@ dmainit(int chan, int maxtransfer)
  *  boundaries)
  */
 long
-dmasetup(int chan, void *va, long len, int isread)
+dmasetup(int chan, void *va, long len, int flags)
 {
 	DMA *dp;
 	ulong pa;
@@ -175,11 +202,11 @@ dmasetup(int chan, void *va, long len, int isread)
 			return -1;
 		if(len > xp->blen)
 			len = xp->blen;
-		if(!isread)
+		if(!(flags & DMAREAD))
 			memmove(xp->bva, va, len);
 		xp->va = va;
 		xp->len = len;
-		xp->isread = isread;
+		xp->flags = flags;
 		pa = xp->bpa;
 	}
 	else
@@ -189,7 +216,7 @@ dmasetup(int chan, void *va, long len, int isread)
 	 * this setup must be atomic
 	 */
 	ilock(dp);
-	mode = (isread ? 0x44 : 0x48) | chan;
+	mode = ((flags & DMAREAD) ? 0x44 : 0x48) | ((flags & DMALOOP) ? 0x10 : 0) | chan;
 	outb(dp->mode, mode);	/* single mode dma (give CPU a chance at mem) */
 	outb(dp->page[chan], pa>>16);
 	outb(dp->cbp, 0);		/* set count & address to their first byte */
@@ -238,7 +265,7 @@ dmaend(int chan)
 	iunlock(dp);
 
 	xp = &dp->x[chan];
-	if(xp->len == 0 || !xp->isread)
+	if(xp->len == 0 || !(xp->flags & DMAREAD))
 		return;
 
 	/*
@@ -248,17 +275,3 @@ dmaend(int chan)
 	xp->len = 0;
 }
 
-/*
-int
-dmacount(int chan)
-{
-	int     retval;
-	DMA     *dp;
- 
-	dp = &dma[(chan>>2)&1];
-	outb(dp->cbp, 0);
-	retval = inb(dp->count[chan]);
-	retval |= inb(dp->count[chan]) << 8;
-	return((retval<<dp->shift)+1);
-}
- */

sys/src/9/pc/fns.h

@@ -18,10 +18,14 @@ int	cpuidentify(void);
 void	cpuidprint(void);
 void	(*cycles)(uvlong*);
 void	delay(int);
+void*	dmabva(int);
 int	dmacount(int);
 int	dmadone(int);
 void	dmaend(int);
 int	dmainit(int, int);
+#define DMAWRITE 0
+#define DMAREAD 1
+#define DMALOOP 2
 long	dmasetup(int, void*, long, int);
 #define	evenaddr(x)				/* x86 doesn't care */
 void	fpclear(void);
@@ -181,5 +185,3 @@ int	xchgw(ushort*, int);
 #define	waserror()	(up->nerrlab++, setlabel(&up->errlab[up->nerrlab-1]))
 #define	KADDR(a)	kaddr(a)
 #define PADDR(a)	paddr((void*)(a))
-
-#define	dcflush(a, b)

sys/src/9/port/devaudio.c

@@ -18,6 +18,7 @@ enum {
 	Qaudioctl,
 	Qaudiostatus,
 	Qvolume,
+
 	Maxaudioprobes = 8,
 };
 
@@ -48,19 +49,26 @@ audioreset(void)
 	int i, ctlrno = 0;
 	Audio **pp;
 	Audioprobe *probe;
+
 	pp = &audiodevs;
 	*pp = malloc(sizeof(Audio));
-	(*pp)->ctlrno = ctlrno++;
-	for(i = 0; i < naudioprobes; i++){
+
+	for(i=0; i<naudioprobes; i++){
 		probe = &audioprobes[i];
-		(*pp)->name = probe->name;
-		while(!probe->probe(*pp)){
+
+		for(;;){
+			memset(*pp, 0, sizeof(Audio));
+			(*pp)->ctlrno = ctlrno;
+			(*pp)->name = probe->name;
+			if(probe->probe(*pp))
+				break;
+
+			ctlrno++;
 			pp = &(*pp)->next;
 			*pp = malloc(sizeof(Audio));
-			(*pp)->ctlrno = ctlrno++;
-			(*pp)->name = probe->name;
 		}
 	}
+
 	free(*pp);
 	*pp = nil;
 }