1999/0403/pc/dma.c (diff list | history)

1998/1125/sys/src/9/pc/dma.c:32,37 – 1999/0403/sys/src/9/pc/dma.c:32,38 (short | long | prev | next)
1991/0803		{
1996/0607		ulong bpa; /* bounce buffer physical address */ void* bva; /* bounce buffer virtual address */
1999/0403		int blen; /* bounce buffer length */
1996/0607		void* va; /* virtual address destination/src */
1991/0803		long len; /* bytes to be transferred */ int isread;
1998/1125/sys/src/9/pc/dma.c:83,111 – 1999/0403/sys/src/9/pc/dma.c:84,121
1997/0404		* initialisation routines of any devices which require DMA to ensure * the allocated bounce buffers are below the 16MB limit.
1993/0915		*/ void
1997/0404		dmainit(int chan)
1999/0403		int dmainit(int chan, int maxtransfer)
1993/0915		{ DMA *dp; DMAxfer *xp;
1997/0404		ulong v;
1993/0915
1999/0403		if(maxtransfer > 64*1024) maxtransfer = 64*1024;
1997/0404		dp = &dma[(chan>>2)&1]; chan = chan & 3; xp = &dp->x[chan]; if(xp->bva != nil) return;                  v = (ulong)xalloc(BY2PG+BY2PG); if(v == 0 || PADDR(v) >= 16*MB){ print("dmainit: chan %d: 0x%luX out of range\n", chan, v); xfree((void*)v); v = 0;
1999/0403		if(xp->bva != nil){ if(xp->blen < maxtransfer) return 1; return 0;
1993/0915		}
1997/0404		xp->bva = (void*)ROUND(v, BY2PG);
1999/0403		xp->bva = xspanalloc(maxtransfer, BY2PG, 64*1024); if(xp->bva == nil) return 1;
1997/0404		xp->bpa = PADDR(xp->bva);
1999/0403		if(xp->bpa >= 16*MB){ xfree(xp->bva); /* doesn't work... */ xp->bva = nil; return 1; } xp->blen = maxtransfer;
1997/0404		xp->len = 0; xp->isread = 0;
1999/0403		return 0;
1993/0915		} /*
1998/1125/sys/src/9/pc/dma.c:132,138 – 1999/0403/sys/src/9/pc/dma.c:142,148
1991/0803		/*
1993/0915		* if this isn't kernel memory or crossing 64k boundary or above 16 meg * use the allocated low memory page.
1999/0403		* use the bounce buffer.
1991/0803		*/
1993/0915		pa = PADDR(va);
1992/1013		if((((ulong)va)&0xF0000000) != KZERO
1998/1125/sys/src/9/pc/dma.c:140,147 – 1999/0403/sys/src/9/pc/dma.c:150,157
1998/1125		|| pa >= 16*MB) {
1997/0404		if(xp->bva == nil) return -1;
1991/0803		if(len > BY2PG) len = BY2PG;
1999/0403		if(len > xp->blen) len = xp->blen;
1991/0803		if(!isread)
1996/0607		memmove(xp->bva, va, len);
1991/0803		xp->va = va;