NetBSD/sys/dev/pci/pcscp.c

692 lines
18 KiB
C

/* $NetBSD: pcscp.c,v 1.8 2000/03/20 05:48:29 tsutsui Exp $ */
/*-
* Copyright (c) 1997, 1998, 1999 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
* NASA Ames Research Center; Izumi Tsutsui.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the NetBSD
* Foundation, Inc. and its contributors.
* 4. Neither the name of The NetBSD Foundation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/*
* pcscp.c: device dependent code for AMD Am53c974 (PCscsi-PCI)
* written by Izumi Tsutsui <tsutsui@ceres.dti.ne.jp>
*
* Technical manual available at
* http://www.amd.com/products/npd/techdocs/techdocs.html
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/device.h>
#include <sys/buf.h>
#include <machine/bus.h>
#include <machine/intr.h>
#include <machine/endian.h>
#include <dev/scsipi/scsi_all.h>
#include <dev/scsipi/scsipi_all.h>
#include <dev/scsipi/scsiconf.h>
#include <dev/scsipi/scsi_message.h>
#include <dev/pci/pcireg.h>
#include <dev/pci/pcivar.h>
#include <dev/pci/pcidevs.h>
#include <dev/ic/ncr53c9xreg.h>
#include <dev/ic/ncr53c9xvar.h>
#include <dev/pci/pcscpreg.h>
#define IO_MAP_REG 0x10
#define MEM_MAP_REG 0x14
struct pcscp_softc {
struct ncr53c9x_softc sc_ncr53c9x; /* glue to MI code */
bus_space_tag_t sc_st; /* bus space tag */
bus_space_handle_t sc_sh; /* bus space handle */
void *sc_ih; /* interrupt cookie */
bus_dma_tag_t sc_dmat; /* DMA tag */
bus_dmamap_t sc_xfermap; /* DMA map for transfers */
u_int32_t *sc_mdladdr; /* MDL array */
bus_dmamap_t sc_mdldmap; /* MDL DMA map */
int sc_active; /* DMA state */
int sc_datain; /* DMA Data Direction */
size_t sc_dmasize; /* DMA size */
char **sc_dmaaddr; /* DMA address */
size_t *sc_dmalen; /* DMA length */
};
#define READ_DMAREG(sc, reg) \
bus_space_read_4((sc)->sc_st, (sc)->sc_sh, (reg))
#define WRITE_DMAREG(sc, reg, var) \
bus_space_write_4((sc)->sc_st, (sc)->sc_sh, (reg), (var))
/* don't have to use MI defines in MD code... */
#undef NCR_READ_REG
#define NCR_READ_REG(sc, reg) pcscp_read_reg((sc), (reg))
#undef NCR_WRITE_REG
#define NCR_WRITE_REG(sc, reg, val) pcscp_write_reg((sc), (reg), (val))
int pcscp_match __P((struct device *, struct cfdata *, void *));
void pcscp_attach __P((struct device *, struct device *, void *));
struct cfattach pcscp_ca = {
sizeof(struct pcscp_softc), pcscp_match, pcscp_attach
};
struct scsipi_device pcscp_dev = {
NULL, /* Use default error handler */
NULL, /* have a queue, served by this */
NULL, /* have no async handler */
NULL, /* Use default 'done' routine */
};
/*
* Functions and the switch for the MI code.
*/
u_char pcscp_read_reg __P((struct ncr53c9x_softc *, int));
void pcscp_write_reg __P((struct ncr53c9x_softc *, int, u_char));
int pcscp_dma_isintr __P((struct ncr53c9x_softc *));
void pcscp_dma_reset __P((struct ncr53c9x_softc *));
int pcscp_dma_intr __P((struct ncr53c9x_softc *));
int pcscp_dma_setup __P((struct ncr53c9x_softc *, caddr_t *,
size_t *, int, size_t *));
void pcscp_dma_go __P((struct ncr53c9x_softc *));
void pcscp_dma_stop __P((struct ncr53c9x_softc *));
int pcscp_dma_isactive __P((struct ncr53c9x_softc *));
struct ncr53c9x_glue pcscp_glue = {
pcscp_read_reg,
pcscp_write_reg,
pcscp_dma_isintr,
pcscp_dma_reset,
pcscp_dma_intr,
pcscp_dma_setup,
pcscp_dma_go,
pcscp_dma_stop,
pcscp_dma_isactive,
NULL, /* gl_clear_latched_intr */
};
int
pcscp_match(parent, match, aux)
struct device *parent;
struct cfdata *match;
void *aux;
{
struct pci_attach_args *pa = aux;
if (PCI_VENDOR(pa->pa_id) != PCI_VENDOR_AMD)
return 0;
switch (PCI_PRODUCT(pa->pa_id)) {
case PCI_PRODUCT_AMD_PCSCSI_PCI:
#if 0
case PCI_PRODUCT_AMD_PCNETS_PCI:
#endif
return 1;
}
return 0;
}
/*
* Attach this instance, and then all the sub-devices
*/
void
pcscp_attach(parent, self, aux)
struct device *parent, *self;
void *aux;
{
struct pci_attach_args *pa = aux;
struct pcscp_softc *esc = (void *)self;
struct ncr53c9x_softc *sc = &esc->sc_ncr53c9x;
bus_space_tag_t st, iot, memt;
bus_space_handle_t sh, ioh, memh;
int ioh_valid, memh_valid;
pci_intr_handle_t ih;
const char *intrstr;
pcireg_t csr;
bus_dma_segment_t seg;
int error, rseg;
ioh_valid = (pci_mapreg_map(pa, IO_MAP_REG,
PCI_MAPREG_TYPE_IO, 0,
&iot, &ioh, NULL, NULL) == 0);
#if 0 /* XXX cannot use memory map? */
memh_valid = (pci_mapreg_map(pa, MEM_MAP_REG,
PCI_MAPREG_TYPE_MEM | PCI_MAPREG_MEM_TYPE_32BIT, 0,
&memt, &memh, NULL, NULL) == 0);
#else
memh_valid = 0;
#endif
if (memh_valid) {
st = memt;
sh = memh;
} else if (ioh_valid) {
st = iot;
sh = ioh;
} else {
printf(": unable to map registers\n");
return;
}
printf("\n");
sc->sc_glue = &pcscp_glue;
esc->sc_st = st;
esc->sc_sh = sh;
esc->sc_dmat = pa->pa_dmat;
csr = pci_conf_read(pa->pa_pc, pa->pa_tag, PCI_COMMAND_STATUS_REG);
pci_conf_write(pa->pa_pc, pa->pa_tag, PCI_COMMAND_STATUS_REG,
csr | PCI_COMMAND_MASTER_ENABLE | PCI_COMMAND_IO_ENABLE);
/*
* XXX More of this should be in ncr53c9x_attach(), but
* XXX should we really poke around the chip that much in
* XXX the MI code? Think about this more...
*/
/*
* Set up static configuration info.
*/
/*
* XXX should read configuration from EEPROM?
*
* MI ncr53c9x driver does not support configuration
* per each target device, though...
*/
sc->sc_id = 7;
sc->sc_cfg1 = sc->sc_id | NCRCFG1_PARENB;
sc->sc_cfg2 = NCRCFG2_SCSI2 | NCRCFG2_FE;
sc->sc_cfg3 = NCRAMDCFG3_IDM | NCRAMDCFG3_FCLK;
sc->sc_cfg4 = NCRAMDCFG4_GE12NS | NCRAMDCFG4_RADE;
sc->sc_rev = NCR_VARIANT_AM53C974;
sc->sc_features = NCR_F_FASTSCSI;
sc->sc_cfg3_fscsi = NCRAMDCFG3_FSCSI;
sc->sc_freq = 40; /* MHz */
/*
* XXX minsync and maxxfer _should_ be set up in MI code,
* XXX but it appears to have some dependency on what sort
* XXX of DMA we're hooked up to, etc.
*/
/*
* This is the value used to start sync negotiations
* Note that the NCR register "SYNCTP" is programmed
* in "clocks per byte", and has a minimum value of 4.
* The SCSI period used in negotiation is one-fourth
* of the time (in nanoseconds) needed to transfer one byte.
* Since the chip's clock is given in MHz, we have the following
* formula: 4 * period = (1000 / freq) * 4
*/
sc->sc_minsync = 1000 / sc->sc_freq;
/* Really no limit, but since we want to fit into the TCR... */
sc->sc_maxxfer = 16 * 1024 * 1024;
/* map and establish interrupt */
if (pci_intr_map(pa->pa_pc, pa->pa_intrtag, pa->pa_intrpin,
pa->pa_intrline, &ih)) {
printf("%s: couldn't map interrupt\n", sc->sc_dev.dv_xname);
return;
}
intrstr = pci_intr_string(pa->pa_pc, ih);
esc->sc_ih = pci_intr_establish(pa->pa_pc, ih, IPL_BIO,
(int (*)(void *))ncr53c9x_intr, esc);
if (esc->sc_ih == NULL) {
printf("%s: couldn't establish interrupt", sc->sc_dev.dv_xname);
if (intrstr != NULL)
printf(" at %s", intrstr);
printf("\n");
return;
}
if (intrstr != NULL)
printf("%s: interrupting at %s\n", sc->sc_dev.dv_xname,
intrstr);
/*
* Create the DMA maps for the data transfers.
*/
#define MDL_SEG_SIZE 0x1000 /* 4kbyte per segment */
#define MDL_SEG_OFFSET 0x0FFF
#define MDL_SIZE (MAXPHYS / MDL_SEG_SIZE + 1) /* no hardware limit? */
if (bus_dmamap_create(esc->sc_dmat, MAXPHYS, MDL_SIZE, MAXPHYS, 0,
BUS_DMA_NOWAIT, &esc->sc_xfermap)) {
printf("%s: can't create dma maps\n", sc->sc_dev.dv_xname);
return;
}
/*
* Allocate and map memory for the MDL.
*/
if ((error = bus_dmamem_alloc(esc->sc_dmat,
sizeof(u_int32_t) * MDL_SIZE, NBPG, 0, &seg, 1, &rseg,
BUS_DMA_NOWAIT)) != 0) {
printf("%s: unable to allocate memory for the MDL, "
"error = %d\n", sc->sc_dev.dv_xname, error);
return;
}
if ((error = bus_dmamem_map(esc->sc_dmat, &seg, rseg,
sizeof(u_int32_t) * MDL_SIZE , (caddr_t *)&esc->sc_mdladdr,
BUS_DMA_NOWAIT|BUS_DMA_COHERENT)) != 0) {
printf("%s: unable to map the MDL memory, error = %d\n",
sc->sc_dev.dv_xname, error);
return;
}
if ((error = bus_dmamap_create(esc->sc_dmat,
sizeof(u_int32_t) * MDL_SIZE, 1, sizeof(u_int32_t) * MDL_SIZE,
0, BUS_DMA_NOWAIT, &esc->sc_mdldmap)) != 0) {
printf("%s: unable to map_create for the MDL, error = %d\n",
sc->sc_dev.dv_xname, error);
return;
}
if ((error = bus_dmamap_load(esc->sc_dmat, esc->sc_mdldmap,
esc->sc_mdladdr, sizeof(u_int32_t) * MDL_SIZE,
NULL, BUS_DMA_NOWAIT)) != 0) {
printf("%s: unable to load for the MDL, error = %d\n",
sc->sc_dev.dv_xname, error);
return;
}
/* Do the common parts of attachment. */
printf("%s", sc->sc_dev.dv_xname);
sc->sc_adapter.scsipi_cmd = ncr53c9x_scsi_cmd;
sc->sc_adapter.scsipi_minphys = minphys;
ncr53c9x_attach(sc, &pcscp_dev);
/* Turn on target selection using the `dma' method */
ncr53c9x_dmaselect = 1;
}
/*
* Glue functions.
*/
u_char
pcscp_read_reg(sc, reg)
struct ncr53c9x_softc *sc;
int reg;
{
struct pcscp_softc *esc = (struct pcscp_softc *)sc;
return bus_space_read_1(esc->sc_st, esc->sc_sh, reg << 2);
}
void
pcscp_write_reg(sc, reg, v)
struct ncr53c9x_softc *sc;
int reg;
u_char v;
{
struct pcscp_softc *esc = (struct pcscp_softc *)sc;
bus_space_write_1(esc->sc_st, esc->sc_sh, reg << 2, v);
}
int
pcscp_dma_isintr(sc)
struct ncr53c9x_softc *sc;
{
return NCR_READ_REG(sc, NCR_STAT) & NCRSTAT_INT;
}
void
pcscp_dma_reset(sc)
struct ncr53c9x_softc *sc;
{
struct pcscp_softc *esc = (struct pcscp_softc *)sc;
WRITE_DMAREG(esc, DMA_CMD, DMACMD_IDLE);
esc->sc_active = 0;
}
int
pcscp_dma_intr(sc)
struct ncr53c9x_softc *sc;
{
struct pcscp_softc *esc = (struct pcscp_softc *)sc;
int trans, resid, i;
bus_dmamap_t dmap = esc->sc_xfermap;
int datain = esc->sc_datain;
u_int32_t dmastat;
char *p = NULL;
dmastat = READ_DMAREG(esc, DMA_STAT);
if (dmastat & DMASTAT_ERR) {
/* XXX not tested... */
WRITE_DMAREG(esc, DMA_CMD, DMACMD_ABORT |
(datain ? DMACMD_DIR : 0));
printf("%s: error: DMA error detected; Aborting.\n",
sc->sc_dev.dv_xname);
bus_dmamap_unload(esc->sc_dmat, dmap);
return -1;
}
if (dmastat & DMASTAT_ABT) {
/* XXX What should be done? */
printf("%s: dma_intr: DMA aborted.\n", sc->sc_dev.dv_xname);
WRITE_DMAREG(esc, DMA_CMD, DMACMD_IDLE |
(datain ? DMACMD_DIR : 0));
esc->sc_active = 0;
return 0;
}
/* This is an "assertion" :) */
if (esc->sc_active == 0)
panic("pcscp dmaintr: DMA wasn't active");
/* DMA has stopped */
esc->sc_active = 0;
if (esc->sc_dmasize == 0) {
/* A "Transfer Pad" operation completed */
NCR_DMA(("dmaintr: discarded %d bytes (tcl=%d, tcm=%d)\n",
NCR_READ_REG(sc, NCR_TCL) |
(NCR_READ_REG(sc, NCR_TCM) << 8),
NCR_READ_REG(sc, NCR_TCL),
NCR_READ_REG(sc, NCR_TCM)));
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 (!datain &&
(resid = (NCR_READ_REG(sc, NCR_FFLAG) & NCRFIFO_FF)) != 0) {
NCR_DMA(("pcscp_dma_intr: empty esp FIFO of %d ", resid));
}
if ((sc->sc_espstat & NCRSTAT_TC) == 0) {
/*
* `Terminal count' is off, so read the residue
* out of the ESP counter registers.
*/
if (datain) {
resid = NCR_READ_REG(sc, NCR_FFLAG) & NCRFIFO_FF;
while (resid > 1)
resid = NCR_READ_REG(sc, NCR_FFLAG) &
NCRFIFO_FF;
WRITE_DMAREG(esc, DMA_CMD, DMACMD_BLAST | DMACMD_MDL |
(datain ? DMACMD_DIR : 0));
for (i = 0; i < 0x8000; i++) /* XXX 0x8000 ? */
if (READ_DMAREG(esc, DMA_STAT) & DMASTAT_BCMP)
break;
/* See the below comments... */
if (resid)
p = *esc->sc_dmaaddr;
}
resid += (NCR_READ_REG(sc, NCR_TCL) |
(NCR_READ_REG(sc, NCR_TCM) << 8) |
((sc->sc_cfg2 & NCRCFG2_FE)
? (NCR_READ_REG(sc, NCR_TCH) << 16) : 0));
if (resid == 0 && esc->sc_dmasize == 65536 &&
(sc->sc_cfg2 & NCRCFG2_FE) == 0)
/* A transfer of 64K is encoded as `TCL=TCM=0' */
resid = 65536;
} else {
while((dmastat & DMASTAT_DONE) == 0)
dmastat = READ_DMAREG(esc, DMA_STAT);
}
WRITE_DMAREG(esc, DMA_CMD, DMACMD_IDLE | (datain ? DMACMD_DIR : 0));
bus_dmamap_sync(esc->sc_dmat, dmap, 0, dmap->dm_mapsize,
datain ? BUS_DMASYNC_POSTREAD : BUS_DMASYNC_POSTWRITE);
bus_dmamap_unload(esc->sc_dmat, dmap);
trans = esc->sc_dmasize - resid;
/*
* From the technical manual notes:
*
* `In some odd byte conditions, one residual byte will be left
* in the SCSI FIFO, and the FIFO flags will never count to 0.
* When this happens, the residual byte should be retrieved
* via PIO following completion of the BLAST operation.'
*/
if (p) {
p += trans;
*p = NCR_READ_REG(sc, NCR_FIFO);
trans++;
}
if (trans < 0) { /* transferred < 0 ? */
#if 0
/*
* This situation can happen in perfectly normal operation
* if the ESP is reselected while using DMA to select
* another target. As such, don't print the warning.
*/
printf("%s: xfer (%d) > req (%d)\n",
sc->sc_dev.dv_xname, trans, esc->sc_dmasize);
#endif
trans = esc->sc_dmasize;
}
NCR_DMA(("dmaintr: tcl=%d, tcm=%d, tch=%d; trans=%d, resid=%d\n",
NCR_READ_REG(sc, NCR_TCL),
NCR_READ_REG(sc, NCR_TCM),
(sc->sc_cfg2 & NCRCFG2_FE)
? NCR_READ_REG(sc, NCR_TCH) : 0,
trans, resid));
*esc->sc_dmalen -= trans;
*esc->sc_dmaaddr += trans;
return 0;
}
int
pcscp_dma_setup(sc, addr, len, datain, dmasize)
struct ncr53c9x_softc *sc;
caddr_t *addr;
size_t *len;
int datain;
size_t *dmasize;
{
struct pcscp_softc *esc = (struct pcscp_softc *)sc;
bus_dmamap_t dmap = esc->sc_xfermap;
u_int32_t *mdl;
int error, nseg, seg;
bus_addr_t s_offset, s_addr;
long rest, count;
WRITE_DMAREG(esc, DMA_CMD, DMACMD_IDLE | (datain ? DMACMD_DIR : 0));
esc->sc_dmaaddr = addr;
esc->sc_dmalen = len;
esc->sc_dmasize = *dmasize;
esc->sc_datain = datain;
#ifdef DIAGNOSTIC
if ((*dmasize / MDL_SEG_SIZE) > MDL_SIZE)
panic("pcscp: transfer size too large");
#endif
/*
* No need to set up DMA in `Transfer Pad' operation.
* (case of *dmasize == 0)
*/
if (*dmasize == 0)
return 0;
error = bus_dmamap_load(esc->sc_dmat, dmap, *esc->sc_dmaaddr,
*esc->sc_dmalen, NULL,
sc->sc_nexus->xs->xs_control & XS_CTL_NOSLEEP ?
BUS_DMA_NOWAIT : BUS_DMA_WAITOK);
if (error) {
printf("%s: unable to load dmamap, error = %d\n",
sc->sc_dev.dv_xname, error);
return error;
}
/* set transfer length */
WRITE_DMAREG(esc, DMA_STC, *dmasize);
/* set up MDL */
mdl = esc->sc_mdladdr;
nseg = dmap->dm_nsegs;
/* the first segment is possibly not aligned with 4k MDL boundary */
count = dmap->dm_segs[0].ds_len;
s_addr = dmap->dm_segs[0].ds_addr;
s_offset = s_addr & MDL_SEG_OFFSET;
s_addr -= s_offset;
rest = MDL_SEG_SIZE - s_offset;
/* set the first MDL and offset */
WRITE_DMAREG(esc, DMA_SPA, s_offset);
*mdl++ = htole32(s_addr);
count -= rest;
/* rests of the first dmamap segment */
while (count > 0) {
s_addr += MDL_SEG_SIZE;
*mdl++ = htole32(s_addr);
count -= MDL_SEG_SIZE;
}
/* the rest dmamap segments are aligned with 4k boundary */
for (seg = 1; seg < nseg; seg++) {
count = dmap->dm_segs[seg].ds_len;
s_addr = dmap->dm_segs[seg].ds_addr;
/* first 4kbyte of each dmamap segment */
*mdl++ = htole32(s_addr);
count -= MDL_SEG_SIZE;
/* trailing contiguous 4k frames of each dmamap segments */
while (count > 0) {
s_addr += MDL_SEG_SIZE;
*mdl++ = htole32(s_addr);
count -= MDL_SEG_SIZE;
}
}
return 0;
}
void
pcscp_dma_go(sc)
struct ncr53c9x_softc *sc;
{
struct pcscp_softc *esc = (struct pcscp_softc *)sc;
bus_dmamap_t dmap = esc->sc_xfermap, mdldmap = esc->sc_mdldmap;
int datain = esc->sc_datain;
/* No DMA transfer in Transfer Pad operation */
if (esc->sc_dmasize == 0)
return;
/* sync transfer buffer */
bus_dmamap_sync(esc->sc_dmat, dmap, 0, dmap->dm_mapsize,
datain ? BUS_DMASYNC_PREREAD : BUS_DMASYNC_PREWRITE);
/* sync MDL */
bus_dmamap_sync(esc->sc_dmat, mdldmap, 0, mdldmap->dm_mapsize,
BUS_DMASYNC_PREWRITE);
/* set Starting MDL Address */
WRITE_DMAREG(esc, DMA_SMDLA, mdldmap->dm_segs[0].ds_addr);
/* set DMA command register bits */
/* XXX DMA Transfer Interrupt Enable bit is broken? */
WRITE_DMAREG(esc, DMA_CMD, DMACMD_IDLE | DMACMD_MDL |
/* DMACMD_INTE | */
(datain ? DMACMD_DIR : 0));
/* issue DMA start command */
WRITE_DMAREG(esc, DMA_CMD, DMACMD_START | DMACMD_MDL |
/* DMACMD_INTE | */
(datain ? DMACMD_DIR : 0));
esc->sc_active = 1;
}
void
pcscp_dma_stop(sc)
struct ncr53c9x_softc *sc;
{
struct pcscp_softc *esc = (struct pcscp_softc *)sc;
/* dma stop */
/* XXX What should we do here ? */
WRITE_DMAREG(esc, DMA_CMD, DMACMD_ABORT |
( esc->sc_datain ? DMACMD_DIR : 0));
esc->sc_active = 0;
}
int
pcscp_dma_isactive(sc)
struct ncr53c9x_softc *sc;
{
struct pcscp_softc *esc = (struct pcscp_softc *)sc;
/* XXX should check esc->sc_active? */
if ((READ_DMAREG(esc, DMA_CMD) & DMACMD_CMD) != DMACMD_IDLE)
return 1;
return 0;
}