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Code the residual computation a bit differently.

This commit is contained in:
pk 1996-06-03 23:48:41 +00:00
parent b58401e04e
commit 3dfb6ab8c0
1 changed files with 24 additions and 9 deletions
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33
sys/arch/sparc/dev/dma.c
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@ -1,4 +1,4 @@
/* $NetBSD: dma.c,v 1.28 1996/05/21 19:07:30 pk Exp $ */
/* $NetBSD: dma.c,v 1.29 1996/06/03 23:48:41 pk Exp $ */
/*
* Copyright (c) 1994 Paul Kranenburg. All rights reserved.
@ -394,7 +394,7 @@ int
espdmaintr(sc)
struct dma_softc *sc;
{
int trans = 0, resid = 0;
int trans, resid;
u_long csr;
csr = DMACSR(sc);
@ -434,20 +434,35 @@ espdmaintr(sc)
return 0;
}
resid = 0;
/*
* If a transfer onto the SCSI bus gets interrupted by the device
* (e.g. for a SAVEPOINTER message), the data in the FIFO counts
* as residual since the ESP counter registers get decremented as
* bytes are clocked into the FIFO.
*/
if (!(csr & D_WRITE) &&
(resid = (ESP_READ_REG(sc->sc_esp, ESP_FFLAG) & ESPFIFO_FF)) != 0) {
ESP_DMA(("dmaintr: empty esp FIFO of %d ", resid));
ESPCMD(sc->sc_esp, ESPCMD_FLUSH);
}
resid += ESP_READ_REG(sc->sc_esp, ESP_TCL) |
(ESP_READ_REG(sc->sc_esp, ESP_TCM) << 8) |
(sc->sc_esp->sc_rev > ESP100A
? (ESP_READ_REG(sc->sc_esp, ESP_TCH) << 16) : 0);
if ((sc->sc_esp->sc_espstat & ESPSTAT_TC) == 0) {
/*
* `Terminal count' is off, so read the residue
* out of the ESP counter registers.
*/
resid += ( ESP_READ_REG(sc->sc_esp, ESP_TCL) |
(ESP_READ_REG(sc->sc_esp, ESP_TCM) << 8) |
(sc->sc_esp->sc_rev > ESP100A
? (ESP_READ_REG(sc->sc_esp, ESP_TCH) << 16)
: 0));
if (resid == 0 && (sc->sc_esp->sc_rev <= ESP100A) &&
(sc->sc_esp->sc_espstat & ESPSTAT_TC) == 0)
resid = 65536;
if (resid == 0 && sc->sc_dmasize == 65536 &&
sc->sc_esp->sc_rev <= ESP100A)
/* A transfer of 64K is encoded as `TCL=TCM=0' */
resid = 65536;
}
trans = sc->sc_dmasize - resid;
if (trans < 0) { /* transferred < 0 ? */