NetBSD/sys/arch/sparc/dev/si.c

1484 lines
38 KiB
C

/* $NetBSD: si.c,v 1.50 1998/11/19 21:49:17 thorpej Exp $ */
/*-
* Copyright (c) 1996 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Adam Glass, David Jones, Gordon W. Ross, and Jason R. Thorpe.
*
* 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.
*/
/*
* This file contains only the machine-dependent parts of the
* Sun4 SCSI driver. (Autoconfig stuff and DMA functions.)
* The machine-independent parts are in ncr5380sbc.c
*
* Supported hardware includes:
* Sun "SCSI Weird" on OBIO (sw: Sun 4/100-series)
* Sun SCSI-3 on VME (si: Sun 4/200-series, others)
*
* The VME variant has a bit to enable or disable the DMA engine,
* but that bit also gates the interrupt line from the NCR5380!
* Therefore, in order to get any interrupt from the 5380, (i.e.
* for reselect) one must clear the DMA engine transfer count and
* then enable DMA. This has the further complication that you
* CAN NOT touch the NCR5380 while the DMA enable bit is set, so
* we have to turn DMA back off before we even look at the 5380.
*
* What wonderfully whacky hardware this is!
*
* David Jones wrote the initial version of this module for NetBSD/sun3,
* which included support for the VME adapter only. (no reselection).
*
* Gordon Ross added support for the Sun 3 OBIO adapter, and re-worked
* both the VME and OBIO code to support disconnect/reselect.
* (Required figuring out the hardware "features" noted above.)
*
* The autoconfiguration boilerplate came from Adam Glass.
*
* Jason R. Thorpe ported the autoconfiguration and VME portions to
* NetBSD/sparc, and added initial support for the 4/100 "SCSI Weird",
* a wacky OBIO variant of the VME SCSI-3. Many thanks to Chuck Cranor
* for lots of helpful tips and suggestions. Thanks also to Paul Kranenburg
* and Chris Torek for bits of insight needed along the way. Thanks to
* David Gilbert and Andrew Gillham who risked filesystem life-and-limb
* for the sake of testing. Andrew Gillham helped work out the bugs
* the the 4/100 DMA code.
*/
/*
* NOTE: support for the 4/100 "SCSI Weird" is not complete! DMA
* works, but interrupts (and, thus, reselection) don't. I don't know
* why, and I don't have a machine to test this on further.
*
* DMA, DMA completion interrupts, and reselection work fine on my
* 4/260 with modern SCSI-II disks attached. I've had reports of
* reselection failing on Sun Shoebox-type configurations where
* there are multiple non-SCSI devices behind Emulex or Adaptec
* bridges. These devices pre-date the SCSI-I spec, and might not
* bahve the way the 5380 code expects. For this reason, only
* DMA is enabled by default in this driver.
*
* Jason R. Thorpe <thorpej@NetBSD.ORG>
* December 8, 1995
*/
#include "opt_ddb.h"
#include <sys/types.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/errno.h>
#include <sys/device.h>
#include <sys/buf.h>
#include <sys/proc.h>
#include <sys/user.h>
#include <vm/vm.h>
#include <machine/bus.h>
#include <machine/autoconf.h>
#include <machine/cpu.h>
#include <machine/pmap.h>
#include <sparc/sparc/vaddrs.h>
#include <sparc/sparc/cpuvar.h>
#include <dev/vme/vmevar.h>
#include <dev/scsipi/scsi_all.h>
#include <dev/scsipi/scsipi_all.h>
#include <dev/scsipi/scsipi_debug.h>
#include <dev/scsipi/scsiconf.h>
#ifndef DDB
#define Debugger()
#endif
#ifndef DEBUG
#define DEBUG XXX
#endif
#define COUNT_SW_LEFTOVERS XXX /* See sw DMA completion code */
#include <dev/ic/ncr5380reg.h>
#include <dev/ic/ncr5380var.h>
#include <sparc/dev/sireg.h>
/*
* Transfers smaller than this are done using PIO
* (on assumption they're not worth DMA overhead)
*/
#define MIN_DMA_LEN 128
/*
* Transfers lager than 65535 bytes need to be split-up.
* (Some of the FIFO logic has only 16 bits counters.)
* Make the size an integer multiple of the page size
* to avoid buf/cluster remap problems. (paranoid?)
*/
#define MAX_DMA_LEN 0xE000
#ifdef DEBUG
int si_debug = 0;
static int si_link_flags = 0 /* | SDEV_DB2 */ ;
#endif
/*
* This structure is used to keep track of mapped DMA requests.
*/
struct si_dma_handle {
int dh_flags;
#define SIDH_BUSY 0x01 /* This DH is in use */
#define SIDH_OUT 0x02 /* DMA does data out (write) */
u_char * dh_addr; /* KVA of start of buffer */
int dh_maplen; /* Original data length */
long dh_startingpa; /* PA of buffer; for "sw" */
bus_dmamap_t dh_dmamap;
#define dh_dvma dh_dmamap->dm_segs[0].ds_addr /* VA of buffer in DVMA space */
};
/*
* The first structure member has to be the ncr5380_softc
* so we can just cast to go back and fourth between them.
*/
struct si_softc {
struct ncr5380_softc ncr_sc;
bus_space_tag_t sc_bustag; /* bus tags */
bus_dma_tag_t sc_dmatag;
volatile struct si_regs *sc_regs;
int sc_adapter_type;
#define BOARD_ID_SI 0
#define BOARD_ID_SW 1
int sc_adapter_iv_am; /* int. vec + address modifier */
struct si_dma_handle *sc_dma;
int sc_xlen; /* length of current DMA segment. */
int sc_options; /* options for this instance. */
};
/*
* Options. By default, DMA is enabled and DMA completion interrupts
* and reselect are disabled. You may enable additional features
* the `flags' directive in your kernel's configuration file.
*
* Alternatively, you can patch your kernel with DDB or some other
* mechanism. The sc_options member of the softc is OR'd with
* the value in si_options.
*
* On the "sw", interrupts (and thus) reselection don't work, so they're
* disabled by default. DMA is still a little dangerous, too.
*
* Note, there's a separate sw_options to make life easier.
*/
#define SI_ENABLE_DMA 0x01 /* Use DMA (maybe polled) */
#define SI_DMA_INTR 0x02 /* DMA completion interrupts */
#define SI_DO_RESELECT 0x04 /* Allow disconnect/reselect */
#define SI_OPTIONS_MASK (SI_ENABLE_DMA|SI_DMA_INTR|SI_DO_RESELECT)
#define SI_OPTIONS_BITS "\10\3RESELECT\2DMA_INTR\1DMA"
int si_options = SI_ENABLE_DMA;
int sw_options = SI_ENABLE_DMA;
/* How long to wait for DMA before declaring an error. */
int si_dma_intr_timo = 500; /* ticks (sec. X 100) */
static int si_match __P((struct device *, struct cfdata *, void *));
static int sw_match __P((struct device *, struct cfdata *, void *));
static void si_attach __P((struct device *, struct device *, void *));
static void sw_attach __P((struct device *, struct device *, void *));
static void si_attach_common __P((struct device *, struct si_softc *));
static int si_intr __P((void *));
static void si_reset_adapter __P((struct ncr5380_softc *));
static void sw_reset_adapter __P((struct ncr5380_softc *));
static void (*reset_adapter) __P((struct ncr5380_softc *));
static void si_minphys __P((struct buf *));
void si_dma_alloc __P((struct ncr5380_softc *));
void si_dma_free __P((struct ncr5380_softc *));
void si_dma_poll __P((struct ncr5380_softc *));
void si_vme_dma_setup __P((struct ncr5380_softc *));
void si_vme_dma_start __P((struct ncr5380_softc *));
void si_vme_dma_eop __P((struct ncr5380_softc *));
void si_vme_dma_stop __P((struct ncr5380_softc *));
void si_vme_intr_on __P((struct ncr5380_softc *));
void si_vme_intr_off __P((struct ncr5380_softc *));
void si_obio_dma_setup __P((struct ncr5380_softc *));
void si_obio_dma_start __P((struct ncr5380_softc *));
void si_obio_dma_eop __P((struct ncr5380_softc *));
void si_obio_dma_stop __P((struct ncr5380_softc *));
void si_obio_intr_on __P((struct ncr5380_softc *));
void si_obio_intr_off __P((struct ncr5380_softc *));
/* This is copied from julian's bt driver */
/* "so we have a default dev struct for our link struct." */
static struct scsipi_device si_dev = {
NULL, /* Use default error handler. */
NULL, /* Use default start handler. */
NULL, /* Use default async handler. */
NULL, /* Use default "done" routine. */
};
/* The Sun SCSI-3 VME controller. */
struct cfattach si_ca = {
sizeof(struct si_softc), si_match, si_attach
};
/* The Sun "SCSI Weird" 4/100 obio controller. */
struct cfattach sw_ca = {
sizeof(struct si_softc), sw_match, sw_attach
};
static int
sw_match(parent, cf, aux)
struct device *parent;
struct cfdata *cf;
void *aux;
{
union obio_attach_args *uoba = aux;
struct obio4_attach_args *oba;
/* Nothing but a Sun 4/100 is going to have these devices. */
if (cpuinfo.cpu_type != CPUTYP_4_100)
return (0);
if (uoba->uoba_isobio4 == 0)
return (0);
/* Make sure there is something there... */
oba = &uoba->uoba_oba4;
return (bus_space_probe(oba->oba_bustag, 0, oba->oba_paddr,
1, /* probe size */
1, /* offset */
0, /* flags */
NULL, NULL));
}
static int
si_match(parent, cf, aux)
struct device *parent;
struct cfdata *cf;
void *aux;
{
struct vme_attach_args *va = aux;
vme_chipset_tag_t ct = va->vma_chipset_tag;
bus_space_tag_t bt = va->vma_bustag;
vme_mod_t mod;
vme_addr_t vme_addr;
/* Nothing but a Sun 4 is going to have these devices. */
if (!CPU_ISSUN4 || cpuinfo.cpu_type == CPUTYP_4_100)
return (0);
/* Make sure there is something there... */
mod = VMEMOD_A24 | VMEMOD_S | VMEMOD_D;
vme_addr = va->vma_reg[0];
if (vme_bus_probe(ct, bt, vme_addr, 1, 1, mod, NULL, 0) == 0)
return (0);
/*
* If this is a VME SCSI board, we have to determine whether
* it is an "sc" (Sun2) or "si" (Sun3) SCSI board. This can
* be determined using the fact that the "sc" board occupies
* 4K bytes in VME space but the "si" board occupies 2K bytes.
*/
vme_addr = va->vma_reg[0];
return (vme_bus_probe(ct, bt, vme_addr, 0x801, 1, mod, NULL, 0));
}
static void
si_attach(parent, self, aux)
struct device *parent, *self;
void *aux;
{
struct si_softc *sc = (struct si_softc *) self;
struct ncr5380_softc *ncr_sc = (struct ncr5380_softc *)sc;
struct vme_attach_args *va = aux;
vme_chipset_tag_t ct = va->vma_chipset_tag;
bus_space_tag_t bt = va->vma_bustag;
bus_space_handle_t bh;
vme_intr_handle_t ih;
vme_mod_t mod;
sc->sc_dmatag = va->vma_dmatag;
mod = VMEMOD_A24 | VMEMOD_D | VMEMOD_S;
if (vme_bus_map(ct, va->vma_reg[0], sizeof(struct si_regs),
mod, bt, &bh) != 0)
panic("%s: vme_bus_map", ncr_sc->sc_dev.dv_xname);
sc->sc_regs = (struct si_regs *)bh;
sc->sc_options = si_options;
reset_adapter = si_reset_adapter;
sc->sc_adapter_type = BOARD_ID_SI;
ncr_sc->sc_dma_setup = si_vme_dma_setup;
ncr_sc->sc_dma_start = si_vme_dma_start;
ncr_sc->sc_dma_eop = si_vme_dma_stop;
ncr_sc->sc_dma_stop = si_vme_dma_stop;
vme_intr_map(ct, va->vma_vec, va->vma_pri, &ih);
vme_intr_establish(ct, ih, si_intr, sc);
printf(" pri %d\n", va->vma_pri);
sc->sc_adapter_iv_am = (mod << 8) | (va->vma_vec & 0xFF);
si_attach_common(parent, sc);
if (sc->sc_options & SI_DO_RESELECT) {
/*
* Need to enable interrupts (and DMA!)
* on this H/W for reselect to work.
*/
ncr_sc->sc_intr_on = si_vme_intr_on;
ncr_sc->sc_intr_off = si_vme_intr_off;
}
bootpath_store(1, NULL);
}
static void
sw_attach(parent, self, aux)
struct device *parent, *self;
void *aux;
{
struct si_softc *sc = (struct si_softc *) self;
struct ncr5380_softc *ncr_sc = (struct ncr5380_softc *)sc;
union obio_attach_args *uoba = aux;
struct obio4_attach_args *oba = &uoba->uoba_oba4;
bus_space_handle_t bh;
struct bootpath *bp;
sc->sc_dmatag = oba->oba_dmatag;
/* Map the controller registers. */
if (obio_bus_map(oba->oba_bustag, oba->oba_paddr,
0,
sizeof(struct si_regs),
BUS_SPACE_MAP_LINEAR,
0, &bh) != 0) {
printf("%s: cannot map registers\n", self->dv_xname);
return;
}
sc->sc_regs = (struct si_regs *)bh;
sc->sc_options = sw_options;
sc->sc_adapter_type = BOARD_ID_SW;
reset_adapter = sw_reset_adapter;
ncr_sc->sc_dma_setup = si_obio_dma_setup;
ncr_sc->sc_dma_start = si_obio_dma_start;
ncr_sc->sc_dma_eop = si_obio_dma_stop;
ncr_sc->sc_dma_stop = si_obio_dma_stop;
ncr_sc->sc_intr_on = si_obio_intr_on;
ncr_sc->sc_intr_off = si_obio_intr_off;
/*
* Establish interrupt channel.
* Default interrupt priority always is 3. At least, that's
* what my board seems to be at. --thorpej
*/
if (oba->oba_pri == -1)
oba->oba_pri = 3;
(void)bus_intr_establish(oba->oba_bustag,
oba->oba_pri, 0,
si_intr, sc);
printf(" pri %d\n", oba->oba_pri);
/*
* If the boot path is "sw" or "si" at the moment and it's me, then
* walk out pointer to the sub-device, ready for the config
* below.
*/
bp = oba->oba_bp;
if (bp != NULL && strcmp(bp->name, "sw") == 0 &&
bp->val[0] == -1 && bp->val[1] == ncr_sc->sc_dev.dv_unit)
bootpath_store(1, bp + 1);
si_attach_common(parent, sc);
bootpath_store(1, NULL);
}
static void
si_attach_common(parent, sc)
struct device *parent;
struct si_softc *sc;
{
struct ncr5380_softc *ncr_sc = (struct ncr5380_softc *)sc;
volatile struct si_regs *regs;
char bits[64];
int i;
/*
* Pull in the options flags. Allow the user to completely
* override the default values.
*/
if ((ncr_sc->sc_dev.dv_cfdata->cf_flags & SI_OPTIONS_MASK) != 0)
sc->sc_options =
(ncr_sc->sc_dev.dv_cfdata->cf_flags & SI_OPTIONS_MASK);
regs = sc->sc_regs;
/*
* Fill in the adapter.
*/
ncr_sc->sc_adapter.scsipi_cmd = ncr5380_scsi_cmd;
ncr_sc->sc_adapter.scsipi_minphys = si_minphys;
/*
* Fill in the prototype scsipi_link.
*/
ncr_sc->sc_link.scsipi_scsi.channel = SCSI_CHANNEL_ONLY_ONE;
ncr_sc->sc_link.adapter_softc = sc;
ncr_sc->sc_link.scsipi_scsi.adapter_target = 7;
ncr_sc->sc_link.adapter = &ncr_sc->sc_adapter;
ncr_sc->sc_link.device = &si_dev;
/*
* Initialize fields used by the MI code
*/
ncr_sc->sci_r0 = &regs->sci.sci_r0;
ncr_sc->sci_r1 = &regs->sci.sci_r1;
ncr_sc->sci_r2 = &regs->sci.sci_r2;
ncr_sc->sci_r3 = &regs->sci.sci_r3;
ncr_sc->sci_r4 = &regs->sci.sci_r4;
ncr_sc->sci_r5 = &regs->sci.sci_r5;
ncr_sc->sci_r6 = &regs->sci.sci_r6;
ncr_sc->sci_r7 = &regs->sci.sci_r7;
/*
* MD function pointers used by the MI code.
*/
ncr_sc->sc_pio_out = ncr5380_pio_out;
ncr_sc->sc_pio_in = ncr5380_pio_in;
ncr_sc->sc_dma_alloc = si_dma_alloc;
ncr_sc->sc_dma_free = si_dma_free;
ncr_sc->sc_dma_poll = si_dma_poll;
ncr_sc->sc_flags = 0;
if ((sc->sc_options & SI_DO_RESELECT) == 0)
ncr_sc->sc_no_disconnect = 0xFF;
if ((sc->sc_options & SI_DMA_INTR) == 0)
ncr_sc->sc_flags |= NCR5380_FORCE_POLLING;
ncr_sc->sc_min_dma_len = MIN_DMA_LEN;
/*
* Allocate DMA handles.
*/
i = SCI_OPENINGS * sizeof(struct si_dma_handle);
sc->sc_dma = (struct si_dma_handle *)malloc(i, M_DEVBUF, M_NOWAIT);
if (sc->sc_dma == NULL)
panic("si: dma handle malloc failed\n");
for (i = 0; i < SCI_OPENINGS; i++) {
sc->sc_dma[i].dh_flags = 0;
/* Allocate a DMA handle */
if (bus_dmamap_create(
sc->sc_dmatag,
MAXPHYS, /* size */
1, /* nsegments */
MAXPHYS, /* maxsegsz */
0, /* boundary */
BUS_DMA_NOWAIT,
&sc->sc_dma[i].dh_dmamap) != 0) {
printf("%s: DMA buffer map create error\n",
ncr_sc->sc_dev.dv_xname);
return;
}
}
if (sc->sc_options) {
printf("%s: options=%s\n", ncr_sc->sc_dev.dv_xname,
bitmask_snprintf(sc->sc_options, SI_OPTIONS_BITS,
bits, sizeof(bits)));
}
#ifdef DEBUG
if (si_debug)
printf("si: Set TheSoftC=%p TheRegs=%p\n", sc, regs);
ncr_sc->sc_link.flags |= si_link_flags;
#endif
/*
* Initialize si board itself.
*/
reset_adapter(ncr_sc);
ncr5380_init(ncr_sc);
ncr5380_reset_scsibus(ncr_sc);
/* Configure sub-devices */
config_found(&ncr_sc->sc_dev, &ncr_sc->sc_link, scsiprint);
}
static void
si_minphys(struct buf *bp)
{
if (bp->b_bcount > MAX_DMA_LEN) {
#ifdef DEBUG
if (si_debug) {
printf("si_minphys len = 0x%x.\n", MAX_DMA_LEN);
Debugger();
}
#endif
bp->b_bcount = MAX_DMA_LEN;
}
return (minphys(bp));
}
#define CSR_WANT (SI_CSR_SBC_IP | SI_CSR_DMA_IP | \
SI_CSR_DMA_CONFLICT | SI_CSR_DMA_BUS_ERR )
static int
si_intr(void *arg)
{
struct si_softc *sc = arg;
volatile struct si_regs *si = sc->sc_regs;
int dma_error, claimed;
u_short csr;
claimed = 0;
dma_error = 0;
/* SBC interrupt? DMA interrupt? */
if (sc->sc_adapter_type == BOARD_ID_SW)
csr = si->sw_csr;
else
csr = si->si_csr;
NCR_TRACE("si_intr: csr=0x%x\n", csr);
if (csr & SI_CSR_DMA_CONFLICT) {
dma_error |= SI_CSR_DMA_CONFLICT;
printf("si_intr: DMA conflict\n");
}
if (csr & SI_CSR_DMA_BUS_ERR) {
dma_error |= SI_CSR_DMA_BUS_ERR;
printf("si_intr: DMA bus error\n");
}
if (dma_error) {
if (sc->ncr_sc.sc_state & NCR_DOINGDMA)
sc->ncr_sc.sc_state |= NCR_ABORTING;
/* Make sure we will call the main isr. */
csr |= SI_CSR_DMA_IP;
}
if (csr & (SI_CSR_SBC_IP | SI_CSR_DMA_IP)) {
claimed = ncr5380_intr(&sc->ncr_sc);
#ifdef DEBUG
if (!claimed) {
printf("si_intr: spurious from SBC\n");
if (si_debug & 4) {
Debugger(); /* XXX */
}
}
#endif
}
return (claimed);
}
static void
si_reset_adapter(struct ncr5380_softc *ncr_sc)
{
struct si_softc *sc = (struct si_softc *)ncr_sc;
volatile struct si_regs *si = sc->sc_regs;
#ifdef DEBUG
if (si_debug) {
printf("si_reset_adapter\n");
}
#endif
/*
* The SCSI3 controller has an 8K FIFO to buffer data between the
* 5380 and the DMA. Make sure it starts out empty.
*
* The reset bits in the CSR are active low.
*/
si->si_csr = 0;
delay(10);
si->si_csr = SI_CSR_FIFO_RES | SI_CSR_SCSI_RES | SI_CSR_INTR_EN;
delay(10);
si->fifo_count = 0;
si->dma_addrh = 0;
si->dma_addrl = 0;
si->dma_counth = 0;
si->dma_countl = 0;
si->si_iv_am = sc->sc_adapter_iv_am;
si->fifo_cnt_hi = 0;
SCI_CLR_INTR(ncr_sc);
}
static void
sw_reset_adapter(struct ncr5380_softc *ncr_sc)
{
struct si_softc *sc = (struct si_softc *)ncr_sc;
volatile struct si_regs *si = sc->sc_regs;
#ifdef DEBUG
if (si_debug) {
printf("sw_reset_adapter\n");
}
#endif
/*
* The reset bits in the CSR are active low.
*/
si->sw_csr = 0;
delay(10);
si->sw_csr = SI_CSR_SCSI_RES;
si->dma_addr = 0;
si->dma_count = 0;
delay(10);
si->sw_csr |= SI_CSR_INTR_EN;
SCI_CLR_INTR(ncr_sc);
}
/*****************************************************************
* Common functions for DMA
****************************************************************/
/*
* Allocate a DMA handle and put it in sc->sc_dma. Prepare
* for DMA transfer. On the Sun4, this means mapping the buffer
* into DVMA space.
*/
void
si_dma_alloc(ncr_sc)
struct ncr5380_softc *ncr_sc;
{
struct si_softc *sc = (struct si_softc *)ncr_sc;
struct sci_req *sr = ncr_sc->sc_current;
struct scsipi_xfer *xs = sr->sr_xs;
struct si_dma_handle *dh;
int i, xlen;
u_long addr;
#ifdef DIAGNOSTIC
if (sr->sr_dma_hand != NULL)
panic("si_dma_alloc: already have DMA handle");
#endif
#if 1 /* XXX - Temporary */
/* XXX - In case we think DMA is completely broken... */
if ((sc->sc_options & SI_ENABLE_DMA) == 0)
return;
#endif
addr = (u_long) ncr_sc->sc_dataptr;
xlen = ncr_sc->sc_datalen;
/* If the DMA start addr is misaligned then do PIO */
if ((addr & 1) || (xlen & 1)) {
printf("si_dma_alloc: misaligned.\n");
return;
}
/* Make sure our caller checked sc_min_dma_len. */
if (xlen < MIN_DMA_LEN)
panic("si_dma_alloc: xlen=0x%x\n", xlen);
/* Find free DMA handle. Guaranteed to find one since we have
as many DMA handles as the driver has processes. */
for (i = 0; i < SCI_OPENINGS; i++) {
if ((sc->sc_dma[i].dh_flags & SIDH_BUSY) == 0)
goto found;
}
panic("si: no free DMA handles.");
found:
dh = &sc->sc_dma[i];
dh->dh_flags = SIDH_BUSY;
dh->dh_addr = (u_char*) addr;
dh->dh_maplen = xlen;
/* Copy the "write" flag for convenience. */
if (xs->flags & SCSI_DATA_OUT)
dh->dh_flags |= SIDH_OUT;
/*
* Double-map the buffer into DVMA space. If we can't re-map
* the buffer, we print a warning and fall back to PIO mode.
*
* NOTE: it is not safe to sleep here!
*/
if (bus_dmamap_load(sc->sc_dmatag, dh->dh_dmamap,
(caddr_t)addr, xlen, NULL, BUS_DMA_NOWAIT) != 0) {
/* Can't remap segment */
printf("si_dma_alloc: can't remap %p/0x%x, doing PIO\n",
dh->dh_addr, dh->dh_maplen);
dh->dh_flags = 0;
return;
}
bus_dmamap_sync(sc->sc_dmatag, dh->dh_dmamap, addr, xlen,
(dh->dh_flags & SIDH_OUT)
? BUS_DMASYNC_PREWRITE
: BUS_DMASYNC_PREREAD);
/* success */
sr->sr_dma_hand = dh;
return;
}
void
si_dma_free(ncr_sc)
struct ncr5380_softc *ncr_sc;
{
struct si_softc *sc = (struct si_softc *)ncr_sc;
struct sci_req *sr = ncr_sc->sc_current;
struct si_dma_handle *dh = sr->sr_dma_hand;
#ifdef DIAGNOSTIC
if (dh == NULL)
panic("si_dma_free: no DMA handle");
#endif
if (ncr_sc->sc_state & NCR_DOINGDMA)
panic("si_dma_free: free while in progress");
if (dh->dh_flags & SIDH_BUSY) {
/* Give back the DVMA space. */
bus_dmamap_sync(sc->sc_dmatag, dh->dh_dmamap,
dh->dh_dvma, dh->dh_maplen,
(dh->dh_flags & SIDH_OUT)
? BUS_DMASYNC_POSTWRITE
: BUS_DMASYNC_POSTREAD);
bus_dmamap_unload(sc->sc_dmatag, dh->dh_dmamap);
dh->dh_flags = 0;
}
sr->sr_dma_hand = NULL;
}
/*
* Poll (spin-wait) for DMA completion.
* Called right after xx_dma_start(), and
* xx_dma_stop() will be called next.
* Same for either VME or OBIO.
*/
void
si_dma_poll(ncr_sc)
struct ncr5380_softc *ncr_sc;
{
struct si_softc *sc = (struct si_softc *)ncr_sc;
struct sci_req *sr = ncr_sc->sc_current;
volatile struct si_regs *si = sc->sc_regs;
int tmo, csr_mask, csr;
/* Make sure DMA started successfully. */
if (ncr_sc->sc_state & NCR_ABORTING)
return;
csr_mask = SI_CSR_SBC_IP | SI_CSR_DMA_IP |
SI_CSR_DMA_CONFLICT | SI_CSR_DMA_BUS_ERR;
tmo = 50000; /* X100 = 5 sec. */
for (;;) {
if (sc->sc_adapter_type == BOARD_ID_SW)
csr = si->sw_csr;
else
csr = si->si_csr;
if (csr & csr_mask)
break;
if (--tmo <= 0) {
printf("%s: DMA timeout (while polling)\n",
ncr_sc->sc_dev.dv_xname);
/* Indicate timeout as MI code would. */
sr->sr_flags |= SR_OVERDUE;
break;
}
delay(100);
}
#ifdef DEBUG
if (si_debug) {
printf("si_dma_poll: done, csr=0x%x\n", csr);
}
#endif
}
/*****************************************************************
* VME functions for DMA
****************************************************************/
/*
* This is called when the bus is going idle,
* so we want to enable the SBC interrupts.
* That is controlled by the DMA enable!
* Who would have guessed!
* What a NASTY trick!
*/
void
si_vme_intr_on(ncr_sc)
struct ncr5380_softc *ncr_sc;
{
struct si_softc *sc = (struct si_softc *)ncr_sc;
volatile struct si_regs *si = sc->sc_regs;
si_vme_dma_setup(ncr_sc);
si->si_csr |= SI_CSR_DMA_EN;
}
/*
* This is called when the bus is idle and we are
* about to start playing with the SBC chip.
*/
void
si_vme_intr_off(ncr_sc)
struct ncr5380_softc *ncr_sc;
{
struct si_softc *sc = (struct si_softc *)ncr_sc;
volatile struct si_regs *si = sc->sc_regs;
si->si_csr &= ~SI_CSR_DMA_EN;
}
/*
* This function is called during the COMMAND or MSG_IN phase
* that preceeds a DATA_IN or DATA_OUT phase, in case we need
* to setup the DMA engine before the bus enters a DATA phase.
*
* XXX: The VME adapter appears to suppress SBC interrupts
* when the FIFO is not empty or the FIFO count is non-zero!
*
* On the VME version we just clear the DMA count and address
* here (to make sure it stays idle) and do the real setup
* later, in dma_start.
*/
void
si_vme_dma_setup(ncr_sc)
struct ncr5380_softc *ncr_sc;
{
struct si_softc *sc = (struct si_softc *)ncr_sc;
volatile struct si_regs *si = sc->sc_regs;
/* Reset the FIFO */
si->si_csr &= ~SI_CSR_FIFO_RES; /* active low */
si->si_csr |= SI_CSR_FIFO_RES;
/* Set direction (assume recv here) */
si->si_csr &= ~SI_CSR_SEND;
/* Assume worst alignment */
si->si_csr |= SI_CSR_BPCON;
si->dma_addrh = 0;
si->dma_addrl = 0;
si->dma_counth = 0;
si->dma_countl = 0;
/* Clear FIFO counter. (also hits dma_count) */
si->fifo_cnt_hi = 0;
si->fifo_count = 0;
}
void
si_vme_dma_start(ncr_sc)
struct ncr5380_softc *ncr_sc;
{
struct si_softc *sc = (struct si_softc *)ncr_sc;
struct sci_req *sr = ncr_sc->sc_current;
struct si_dma_handle *dh = sr->sr_dma_hand;
volatile struct si_regs *si = sc->sc_regs;
u_long data_pa;
int xlen;
/*
* Get the DVMA mapping for this segment.
*/
data_pa = (u_long)(dh->dh_dvma);
if (data_pa & 1)
panic("si_dma_start: bad pa=0x%lx", data_pa);
xlen = ncr_sc->sc_datalen;
xlen &= ~1;
sc->sc_xlen = xlen; /* XXX: or less... */
#ifdef DEBUG
if (si_debug & 2) {
printf("si_dma_start: dh=%p, pa=0x%lx, xlen=%d\n",
dh, data_pa, xlen);
}
#endif
/*
* Set up the DMA controller.
* Note that (dh->dh_len < sc_datalen)
*/
si->si_csr &= ~SI_CSR_FIFO_RES; /* active low */
si->si_csr |= SI_CSR_FIFO_RES;
/* Set direction (send/recv) */
if (dh->dh_flags & SIDH_OUT) {
si->si_csr |= SI_CSR_SEND;
} else {
si->si_csr &= ~SI_CSR_SEND;
}
if (data_pa & 2) {
si->si_csr |= SI_CSR_BPCON;
} else {
si->si_csr &= ~SI_CSR_BPCON;
}
si->dma_addrh = (u_short)(data_pa >> 16);
si->dma_addrl = (u_short)(data_pa & 0xFFFF);
si->dma_counth = (u_short)(xlen >> 16);
si->dma_countl = (u_short)(xlen & 0xFFFF);
#if 1
/* Set it anyway, even though dma_count hits it? */
si->fifo_cnt_hi = (u_short)(xlen >> 16);
si->fifo_count = (u_short)(xlen & 0xFFFF);
#endif
#ifdef DEBUG
if (si->fifo_count != xlen) {
printf("si_dma_start: Fifo_count=0x%x, xlen=0x%x\n",
si->fifo_count, xlen);
Debugger();
}
#endif
/*
* Acknowledge the phase change. (After DMA setup!)
* Put the SBIC into DMA mode, and start the transfer.
*/
if (dh->dh_flags & SIDH_OUT) {
*ncr_sc->sci_tcmd = PHASE_DATA_OUT;
SCI_CLR_INTR(ncr_sc);
*ncr_sc->sci_icmd = SCI_ICMD_DATA;
*ncr_sc->sci_mode |= (SCI_MODE_DMA | SCI_MODE_DMA_IE);
*ncr_sc->sci_dma_send = 0; /* start it */
} else {
*ncr_sc->sci_tcmd = PHASE_DATA_IN;
SCI_CLR_INTR(ncr_sc);
*ncr_sc->sci_icmd = 0;
*ncr_sc->sci_mode |= (SCI_MODE_DMA | SCI_MODE_DMA_IE);
*ncr_sc->sci_irecv = 0; /* start it */
}
/* Let'er rip! */
si->si_csr |= SI_CSR_DMA_EN;
ncr_sc->sc_state |= NCR_DOINGDMA;
#ifdef DEBUG
if (si_debug & 2) {
printf("si_dma_start: started, flags=0x%x\n",
ncr_sc->sc_state);
}
#endif
}
void
si_vme_dma_eop(ncr_sc)
struct ncr5380_softc *ncr_sc;
{
/* Not needed - DMA was stopped prior to examining sci_csr */
}
void
si_vme_dma_stop(ncr_sc)
struct ncr5380_softc *ncr_sc;
{
struct si_softc *sc = (struct si_softc *)ncr_sc;
struct sci_req *sr = ncr_sc->sc_current;
struct si_dma_handle *dh = sr->sr_dma_hand;
volatile struct si_regs *si = sc->sc_regs;
int resid, ntrans;
if ((ncr_sc->sc_state & NCR_DOINGDMA) == 0) {
#ifdef DEBUG
printf("si_dma_stop: dma not running\n");
#endif
return;
}
ncr_sc->sc_state &= ~NCR_DOINGDMA;
/* First, halt the DMA engine. */
si->si_csr &= ~SI_CSR_DMA_EN; /* VME only */
if (si->si_csr & (SI_CSR_DMA_CONFLICT | SI_CSR_DMA_BUS_ERR)) {
printf("si: DMA error, csr=0x%x, reset\n", si->si_csr);
sr->sr_xs->error = XS_DRIVER_STUFFUP;
ncr_sc->sc_state |= NCR_ABORTING;
si_reset_adapter(ncr_sc);
}
/* Note that timeout may have set the error flag. */
if (ncr_sc->sc_state & NCR_ABORTING)
goto out;
/*
* Now try to figure out how much actually transferred
*
* The fifo_count does not reflect how many bytes were
* actually transferred for VME.
*
* SCSI-3 VME interface is a little funny on writes:
* if we have a disconnect, the dma has overshot by
* one byte and the resid needs to be incremented.
* Only happens for partial transfers.
* (Thanks to Matt Jacob)
*/
resid = si->fifo_count & 0xFFFF;
if (dh->dh_flags & SIDH_OUT)
if ((resid > 0) && (resid < sc->sc_xlen))
resid++;
ntrans = sc->sc_xlen - resid;
#ifdef DEBUG
if (si_debug & 2) {
printf("si_dma_stop: resid=0x%x ntrans=0x%x\n",
resid, ntrans);
}
#endif
if (ntrans < MIN_DMA_LEN) {
printf("si: fifo count: 0x%x\n", resid);
ncr_sc->sc_state |= NCR_ABORTING;
goto out;
}
if (ntrans > ncr_sc->sc_datalen)
panic("si_dma_stop: excess transfer");
/* Adjust data pointer */
ncr_sc->sc_dataptr += ntrans;
ncr_sc->sc_datalen -= ntrans;
#ifdef DEBUG
if (si_debug & 2) {
printf("si_dma_stop: ntrans=0x%x\n", ntrans);
}
#endif
/*
* After a read, we may need to clean-up
* "Left-over bytes" (yuck!)
*/
if (((dh->dh_flags & SIDH_OUT) == 0) &&
((si->si_csr & SI_CSR_LOB) != 0))
{
char *cp = ncr_sc->sc_dataptr;
#ifdef DEBUG
printf("si: Got Left-over bytes!\n");
#endif
if (si->si_csr & SI_CSR_BPCON) {
/* have SI_CSR_BPCON */
cp[-1] = (si->si_bprl & 0xff00) >> 8;
} else {
switch (si->si_csr & SI_CSR_LOB) {
case SI_CSR_LOB_THREE:
cp[-3] = (si->si_bprh & 0xff00) >> 8;
cp[-2] = (si->si_bprh & 0x00ff);
cp[-1] = (si->si_bprl & 0xff00) >> 8;
break;
case SI_CSR_LOB_TWO:
cp[-2] = (si->si_bprh & 0xff00) >> 8;
cp[-1] = (si->si_bprh & 0x00ff);
break;
case SI_CSR_LOB_ONE:
cp[-1] = (si->si_bprh & 0xff00) >> 8;
break;
}
}
}
out:
si->dma_addrh = 0;
si->dma_addrl = 0;
si->dma_counth = 0;
si->dma_countl = 0;
si->fifo_cnt_hi = 0;
si->fifo_count = 0;
/* Put SBIC back in PIO mode. */
*ncr_sc->sci_mode &= ~(SCI_MODE_DMA | SCI_MODE_DMA_IE);
*ncr_sc->sci_icmd = 0;
}
/*****************************************************************
* OBIO functions for DMA
****************************************************************/
/*
* This is called when the bus is going idle,
* so we want to enable the SBC interrupts.
* That is controlled by the DMA enable!
* Who would have guessed!
* What a NASTY trick!
*
* XXX THIS MIGHT NOT WORK RIGHT!
*/
void
si_obio_intr_on(ncr_sc)
struct ncr5380_softc *ncr_sc;
{
struct si_softc *sc = (struct si_softc *)ncr_sc;
volatile struct si_regs *si = sc->sc_regs;
si_obio_dma_setup(ncr_sc);
si->sw_csr |= SI_CSR_DMA_EN;
}
/*
* This is called when the bus is idle and we are
* about to start playing with the SBC chip.
*
* XXX THIS MIGHT NOT WORK RIGHT!
*/
void
si_obio_intr_off(ncr_sc)
struct ncr5380_softc *ncr_sc;
{
struct si_softc *sc = (struct si_softc *)ncr_sc;
volatile struct si_regs *si = sc->sc_regs;
si->sw_csr &= ~SI_CSR_DMA_EN;
}
/*
* This function is called during the COMMAND or MSG_IN phase
* that preceeds a DATA_IN or DATA_OUT phase, in case we need
* to setup the DMA engine before the bus enters a DATA phase.
*
* On the OBIO version we just clear the DMA count and address
* here (to make sure it stays idle) and do the real setup
* later, in dma_start.
*/
void
si_obio_dma_setup(ncr_sc)
struct ncr5380_softc *ncr_sc;
{
struct si_softc *sc = (struct si_softc *)ncr_sc;
volatile struct si_regs *si = sc->sc_regs;
/* No FIFO to reset on "sw". */
/* Set direction (assume recv here) */
si->sw_csr &= ~SI_CSR_SEND;
si->dma_addr = 0;
si->dma_count = 0;
}
void
si_obio_dma_start(ncr_sc)
struct ncr5380_softc *ncr_sc;
{
struct si_softc *sc = (struct si_softc *)ncr_sc;
struct sci_req *sr = ncr_sc->sc_current;
struct si_dma_handle *dh = sr->sr_dma_hand;
volatile struct si_regs *si = sc->sc_regs;
u_long data_pa;
int xlen, adj, adjlen;
/*
* Get the DVMA mapping for this segment.
*/
data_pa = (u_long)(dh->dh_dvma);
if (data_pa & 1)
panic("si_dma_start: bad pa=0x%lx", data_pa);
xlen = ncr_sc->sc_datalen;
xlen &= ~1;
sc->sc_xlen = xlen; /* XXX: or less... */
#ifdef DEBUG
if (si_debug & 2) {
printf("si_dma_start: dh=%p, pa=0x%lx, xlen=%d\n",
dh, data_pa, xlen);
}
#endif
/*
* Set up the DMA controller.
* Note that (dh->dh_len < sc_datalen)
*/
/* Set direction (send/recv) */
if (dh->dh_flags & SIDH_OUT) {
si->sw_csr |= SI_CSR_SEND;
} else {
si->sw_csr &= ~SI_CSR_SEND;
}
/*
* The "sw" needs longword aligned transfers. We
* detect a shortword aligned transfer here, and adjust the
* DMA transfer by 2 bytes. These two bytes are read/written
* in PIO mode just before the DMA is started.
*/
adj = 0;
if (data_pa & 2) {
adj = 2;
#ifdef DEBUG
if (si_debug & 2)
printf("si_dma_start: adjusted up %d bytes\n", adj);
#endif
}
/* We have to frob the address on the "sw". */
dh->dh_startingpa = (data_pa | 0xF00000);
si->dma_addr = (int)(dh->dh_startingpa + adj);
si->dma_count = (xlen - adj);
/*
* Acknowledge the phase change. (After DMA setup!)
* Put the SBIC into DMA mode, and start the transfer.
*/
if (dh->dh_flags & SIDH_OUT) {
*ncr_sc->sci_tcmd = PHASE_DATA_OUT;
if (adj) {
adjlen = ncr5380_pio_out(ncr_sc, PHASE_DATA_OUT,
adj, dh->dh_addr);
if (adjlen != adj)
printf("%s: bad outgoing adj, %d != %d\n",
ncr_sc->sc_dev.dv_xname, adjlen, adj);
}
SCI_CLR_INTR(ncr_sc);
*ncr_sc->sci_icmd = SCI_ICMD_DATA;
*ncr_sc->sci_mode |= (SCI_MODE_DMA | SCI_MODE_DMA_IE);
*ncr_sc->sci_dma_send = 0; /* start it */
} else {
*ncr_sc->sci_tcmd = PHASE_DATA_IN;
if (adj) {
adjlen = ncr5380_pio_in(ncr_sc, PHASE_DATA_IN,
adj, dh->dh_addr);
if (adjlen != adj)
printf("%s: bad incoming adj, %d != %d\n",
ncr_sc->sc_dev.dv_xname, adjlen, adj);
}
SCI_CLR_INTR(ncr_sc);
*ncr_sc->sci_icmd = 0;
*ncr_sc->sci_mode |= (SCI_MODE_DMA | SCI_MODE_DMA_IE);
*ncr_sc->sci_irecv = 0; /* start it */
}
/* Let'er rip! */
si->sw_csr |= SI_CSR_DMA_EN;
ncr_sc->sc_state |= NCR_DOINGDMA;
#ifdef DEBUG
if (si_debug & 2) {
printf("si_dma_start: started, flags=0x%x\n",
ncr_sc->sc_state);
}
#endif
}
void
si_obio_dma_eop(ncr_sc)
struct ncr5380_softc *ncr_sc;
{
/* Not needed - DMA was stopped prior to examining sci_csr */
}
#if (defined(DEBUG) || defined(DIAGNOSTIC)) && !defined(COUNT_SW_LEFTOVERS)
#define COUNT_SW_LEFTOVERS
#endif
#ifdef COUNT_SW_LEFTOVERS
/*
* Let's find out how often these occur. Read these with DDB from time
* to time.
*/
int sw_3_leftover = 0;
int sw_2_leftover = 0;
int sw_1_leftover = 0;
int sw_0_leftover = 0;
#endif
void
si_obio_dma_stop(ncr_sc)
struct ncr5380_softc *ncr_sc;
{
struct si_softc *sc = (struct si_softc *)ncr_sc;
struct sci_req *sr = ncr_sc->sc_current;
struct si_dma_handle *dh = sr->sr_dma_hand;
volatile struct si_regs *si = sc->sc_regs;
int ntrans = 0, Dma_addr;
if ((ncr_sc->sc_state & NCR_DOINGDMA) == 0) {
#ifdef DEBUG
printf("si_dma_stop: dma not running\n");
#endif
return;
}
ncr_sc->sc_state &= ~NCR_DOINGDMA;
/* First, halt the DMA engine. */
si->sw_csr &= ~SI_CSR_DMA_EN;
/*
* XXX HARDWARE BUG!
* Apparently, some early 4/100 SCSI controllers had a hardware
* bug that caused the controller to do illegal memory access.
* We see this as SI_CSR_DMA_BUS_ERR (makes sense). To work around
* this, we simply need to clean up after ourselves ... there will
* be as many as 3 bytes left over. Since we clean up "left-over"
* bytes on every read anyway, we just continue to chug along
* if SI_CSR_DMA_BUS_ERR is asserted. (This was probably worked
* around in hardware later with the "left-over byte" indicator
* in the VME controller.)
*/
#if 0
if (si->sw_csr & (SI_CSR_DMA_CONFLICT | SI_CSR_DMA_BUS_ERR)) {
#else
if (si->sw_csr & (SI_CSR_DMA_CONFLICT)) {
#endif
printf("sw: DMA error, csr=0x%x, reset\n", si->sw_csr);
sr->sr_xs->error = XS_DRIVER_STUFFUP;
ncr_sc->sc_state |= NCR_ABORTING;
si_reset_adapter(ncr_sc);
}
/* Note that timeout may have set the error flag. */
if (ncr_sc->sc_state & NCR_ABORTING)
goto out;
/*
* Now try to figure out how much actually transferred
*
* The "sw" doesn't have a FIFO or a bcr, so we've stored
* the starting PA of the transfer in the DMA handle,
* and subtract it from the ending PA left in the dma_addr
* register.
*/
Dma_addr = si->dma_addr;
ntrans = (Dma_addr - dh->dh_startingpa);
#ifdef DEBUG
if (si_debug & 2) {
printf("si_dma_stop: ntrans=0x%x\n", ntrans);
}
#endif
if (ntrans < MIN_DMA_LEN) {
printf("sw: short transfer\n");
ncr_sc->sc_state |= NCR_ABORTING;
goto out;
}
if (ntrans > ncr_sc->sc_datalen)
panic("si_dma_stop: excess transfer");
/* Adjust data pointer */
ncr_sc->sc_dataptr += ntrans;
ncr_sc->sc_datalen -= ntrans;
/*
* After a read, we may need to clean-up
* "Left-over bytes" (yuck!) The "sw" doesn't
* have a "left-over" indicator, so we have to so
* this no matter what. Ick.
*/
if ((dh->dh_flags & SIDH_OUT) == 0) {
char *cp = ncr_sc->sc_dataptr;
switch (Dma_addr & 3) {
case 3:
cp[0] = (si->sw_bpr & 0xff000000) >> 24;
cp[1] = (si->sw_bpr & 0x00ff0000) >> 16;
cp[2] = (si->sw_bpr & 0x0000ff00) >> 8;
#ifdef COUNT_SW_LEFTOVERS
++sw_3_leftover;
#endif
break;
case 2:
cp[0] = (si->sw_bpr & 0xff000000) >> 24;
cp[1] = (si->sw_bpr & 0x00ff0000) >> 16;
#ifdef COUNT_SW_LEFTOVERS
++sw_2_leftover;
#endif
break;
case 1:
cp[0] = (si->sw_bpr & 0xff000000) >> 24;
#ifdef COUNT_SW_LEFTOVERS
++sw_1_leftover;
#endif
break;
#ifdef COUNT_SW_LEFTOVERS
default:
++sw_0_leftover;
break;
#endif
}
}
out:
si->dma_addr = 0;
si->dma_count = 0;
/* Put SBIC back in PIO mode. */
*ncr_sc->sci_mode &= ~(SCI_MODE_DMA | SCI_MODE_DMA_IE);
*ncr_sc->sci_icmd = 0;
#ifdef DEBUG
if (si_debug & 2) {
printf("si_dma_stop: ntrans=0x%x\n", ntrans);
}
#endif
}