NetBSD/sys/dev/ic/lance.c

818 lines
19 KiB
C

/* $NetBSD: lance.c,v 1.54 2018/09/03 16:29:31 riastradh Exp $ */
/*-
* Copyright (c) 1997, 1998 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Charles M. Hannum and by Jason R. Thorpe of the Numerical Aerospace
* Simulation Facility, NASA Ames Research Center.
*
* 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.
*
* 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.
*/
/*-
* Copyright (c) 1992, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Ralph Campbell and Rick Macklem.
*
* 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. Neither the name of the University 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 REGENTS 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 REGENTS 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.
*
* @(#)if_le.c 8.2 (Berkeley) 11/16/93
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: lance.c,v 1.54 2018/09/03 16:29:31 riastradh Exp $");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/syslog.h>
#include <sys/socket.h>
#include <sys/device.h>
#include <sys/malloc.h>
#include <sys/ioctl.h>
#include <sys/errno.h>
#include <sys/rndsource.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_ether.h>
#include <net/if_media.h>
#include <net/bpf.h>
#include <dev/ic/lancereg.h>
#include <dev/ic/lancevar.h>
#if defined(_KERNEL_OPT)
#include "opt_ddb.h"
#endif
#ifdef DDB
#define integrate
#define hide
#else
#define integrate static inline
#define hide static
#endif
integrate struct mbuf *lance_get(struct lance_softc *, int, int);
hide bool lance_shutdown(device_t, int);
int lance_mediachange(struct ifnet *);
void lance_mediastatus(struct ifnet *, struct ifmediareq *);
static inline u_int16_t ether_cmp(void *, void *);
void lance_stop(struct ifnet *, int);
int lance_ioctl(struct ifnet *, u_long, void *);
void lance_watchdog(struct ifnet *);
/*
* Compare two Ether/802 addresses for equality, inlined and
* unrolled for speed. Use this like memcmp().
*
* XXX: Add <machine/inlines.h> for stuff like this?
* XXX: or maybe add it to libkern.h instead?
*
* "I'd love to have an inline assembler version of this."
* XXX: Who wanted that? mycroft? I wrote one, but this
* version in C is as good as hand-coded assembly. -gwr
*
* Please do NOT tweak this without looking at the actual
* assembly code generated before and after your tweaks!
*/
static inline uint16_t
ether_cmp(void *one, void *two)
{
uint16_t *a = (uint16_t *)one;
uint16_t *b = (uint16_t *)two;
uint16_t diff;
#ifdef m68k
/*
* The post-increment-pointer form produces the best
* machine code for m68k. This was carefully tuned
* so it compiles to just 8 short (2-byte) op-codes!
*/
diff = *a++ - *b++;
diff |= *a++ - *b++;
diff |= *a++ - *b++;
#else
/*
* Most modern CPUs do better with a single expresion.
* Note that short-cut evaluation is NOT helpful here,
* because it just makes the code longer, not faster!
*/
diff = (a[0] - b[0]) | (a[1] - b[1]) | (a[2] - b[2]);
#endif
return (diff);
}
#define ETHER_CMP ether_cmp
#ifdef LANCE_REVC_BUG
/* Make sure this is short-aligned, for ether_cmp(). */
static uint16_t bcast_enaddr[3] = { ~0, ~0, ~0 };
#endif
void
lance_config(struct lance_softc *sc)
{
int i, nbuf;
struct ifnet *ifp = &sc->sc_ethercom.ec_if;
/* Initialize ifnet structure. */
strcpy(ifp->if_xname, device_xname(sc->sc_dev));
ifp->if_softc = sc;
ifp->if_start = sc->sc_start;
ifp->if_ioctl = lance_ioctl;
ifp->if_watchdog = lance_watchdog;
ifp->if_init = lance_init;
ifp->if_stop = lance_stop;
ifp->if_flags =
IFF_BROADCAST | IFF_SIMPLEX | IFF_NOTRAILERS | IFF_MULTICAST;
#ifdef LANCE_REVC_BUG
ifp->if_flags &= ~IFF_MULTICAST;
#endif
IFQ_SET_READY(&ifp->if_snd);
/* Initialize ifmedia structures. */
ifmedia_init(&sc->sc_media, 0, lance_mediachange, lance_mediastatus);
if (sc->sc_supmedia != NULL) {
for (i = 0; i < sc->sc_nsupmedia; i++)
ifmedia_add(&sc->sc_media, sc->sc_supmedia[i],
0, NULL);
ifmedia_set(&sc->sc_media, sc->sc_defaultmedia);
} else {
ifmedia_add(&sc->sc_media, IFM_ETHER|IFM_MANUAL, 0, NULL);
ifmedia_set(&sc->sc_media, IFM_ETHER|IFM_MANUAL);
}
switch (sc->sc_memsize) {
case 8192:
sc->sc_nrbuf = 4;
sc->sc_ntbuf = 1;
break;
case 16384:
sc->sc_nrbuf = 8;
sc->sc_ntbuf = 2;
break;
case 32768:
sc->sc_nrbuf = 16;
sc->sc_ntbuf = 4;
break;
case 65536:
sc->sc_nrbuf = 32;
sc->sc_ntbuf = 8;
break;
case 131072:
sc->sc_nrbuf = 64;
sc->sc_ntbuf = 16;
break;
case 262144:
sc->sc_nrbuf = 128;
sc->sc_ntbuf = 32;
break;
default:
/* weird memory size; cope with it */
nbuf = sc->sc_memsize / LEBLEN;
sc->sc_ntbuf = nbuf / 5;
sc->sc_nrbuf = nbuf - sc->sc_ntbuf;
}
aprint_normal(": address %s\n", ether_sprintf(sc->sc_enaddr));
aprint_normal_dev(sc->sc_dev,
"%d receive buffers, %d transmit buffers\n",
sc->sc_nrbuf, sc->sc_ntbuf);
/* Make sure the chip is stopped. */
lance_stop(ifp, 0);
/* claim 802.1q capability */
sc->sc_ethercom.ec_capabilities |= ETHERCAP_VLAN_MTU;
/* Attach the interface. */
if_attach(ifp);
ether_ifattach(ifp, sc->sc_enaddr);
if (pmf_device_register1(sc->sc_dev, NULL, NULL, lance_shutdown))
pmf_class_network_register(sc->sc_dev, ifp);
else
aprint_error_dev(sc->sc_dev,
"couldn't establish power handler\n");
sc->sc_rbufaddr = malloc(sc->sc_nrbuf * sizeof(int), M_DEVBUF,
M_WAITOK);
sc->sc_tbufaddr = malloc(sc->sc_ntbuf * sizeof(int), M_DEVBUF,
M_WAITOK);
rnd_attach_source(&sc->rnd_source, device_xname(sc->sc_dev),
RND_TYPE_NET, RND_FLAG_DEFAULT);
}
void
lance_reset(struct lance_softc *sc)
{
int s;
s = splnet();
lance_init(&sc->sc_ethercom.ec_if);
splx(s);
}
void
lance_stop(struct ifnet *ifp, int disable)
{
struct lance_softc *sc = ifp->if_softc;
(*sc->sc_wrcsr)(sc, LE_CSR0, LE_C0_STOP);
}
/*
* Initialization of interface; set up initialization block
* and transmit/receive descriptor rings.
*/
int
lance_init(struct ifnet *ifp)
{
struct lance_softc *sc = ifp->if_softc;
int timo;
u_long a;
(*sc->sc_wrcsr)(sc, LE_CSR0, LE_C0_STOP);
DELAY(100);
/* Newer LANCE chips have a reset register */
if (sc->sc_hwreset)
(*sc->sc_hwreset)(sc);
/* Set the correct byte swapping mode, etc. */
(*sc->sc_wrcsr)(sc, LE_CSR3, sc->sc_conf3);
/* Set up LANCE init block. */
(*sc->sc_meminit)(sc);
/* Give LANCE the physical address of its init block. */
a = sc->sc_addr + LE_INITADDR(sc);
(*sc->sc_wrcsr)(sc, LE_CSR1, a);
(*sc->sc_wrcsr)(sc, LE_CSR2, a >> 16);
/* Try to initialize the LANCE. */
DELAY(100);
(*sc->sc_wrcsr)(sc, LE_CSR0, LE_C0_INIT);
/* Wait for initialization to finish. */
for (timo = 100000; timo; timo--)
if ((*sc->sc_rdcsr)(sc, LE_CSR0) & LE_C0_IDON)
break;
if ((*sc->sc_rdcsr)(sc, LE_CSR0) & LE_C0_IDON) {
/* Start the LANCE. */
(*sc->sc_wrcsr)(sc, LE_CSR0, LE_C0_INEA | LE_C0_STRT);
ifp->if_flags |= IFF_RUNNING;
ifp->if_flags &= ~IFF_OACTIVE;
ifp->if_timer = 0;
(*sc->sc_start)(ifp);
} else
printf("%s: controller failed to initialize\n",
device_xname(sc->sc_dev));
if (sc->sc_hwinit)
(*sc->sc_hwinit)(sc);
return (0);
}
/*
* Routine to copy from mbuf chain to transmit buffer in
* network buffer memory.
*/
int
lance_put(struct lance_softc *sc, int boff, struct mbuf *m)
{
struct mbuf *n;
int len, tlen = 0;
for (; m; m = n) {
len = m->m_len;
if (len == 0) {
n = m_free(m);
continue;
}
(*sc->sc_copytobuf)(sc, mtod(m, void *), boff, len);
boff += len;
tlen += len;
n = m_free(m);
}
if (tlen < LEMINSIZE) {
(*sc->sc_zerobuf)(sc, boff, LEMINSIZE - tlen);
tlen = LEMINSIZE;
}
return (tlen);
}
/*
* Pull data off an interface.
* Len is length of data, with local net header stripped.
* We copy the data into mbufs. When full cluster sized units are present
* we copy into clusters.
*/
integrate struct mbuf *
lance_get(struct lance_softc *sc, int boff, int totlen)
{
struct mbuf *m, *m0, *newm;
int len;
MGETHDR(m0, M_DONTWAIT, MT_DATA);
if (m0 == 0)
return (0);
m_set_rcvif(m0, &sc->sc_ethercom.ec_if);
m0->m_pkthdr.len = totlen;
len = MHLEN;
m = m0;
while (totlen > 0) {
if (totlen >= MINCLSIZE) {
MCLGET(m, M_DONTWAIT);
if ((m->m_flags & M_EXT) == 0)
goto bad;
len = MCLBYTES;
}
if (m == m0) {
char *newdata = (char *)
ALIGN(m->m_data + sizeof(struct ether_header)) -
sizeof(struct ether_header);
len -= newdata - m->m_data;
m->m_data = newdata;
}
m->m_len = len = uimin(totlen, len);
(*sc->sc_copyfrombuf)(sc, mtod(m, void *), boff, len);
boff += len;
totlen -= len;
if (totlen > 0) {
MGET(newm, M_DONTWAIT, MT_DATA);
if (newm == 0)
goto bad;
len = MLEN;
m = m->m_next = newm;
}
}
return (m0);
bad:
m_freem(m0);
return (0);
}
/*
* Pass a packet to the higher levels.
*/
void
lance_read(struct lance_softc *sc, int boff, int len)
{
struct mbuf *m;
struct ifnet *ifp = &sc->sc_ethercom.ec_if;
struct ether_header *eh;
if (len <= sizeof(struct ether_header) ||
len > ((sc->sc_ethercom.ec_capenable & ETHERCAP_VLAN_MTU) ?
ETHER_VLAN_ENCAP_LEN + ETHERMTU + sizeof(struct ether_header) :
ETHERMTU + sizeof(struct ether_header))) {
#ifdef LEDEBUG
printf("%s: invalid packet size %d; dropping\n",
device_xname(sc->sc_dev), len);
#endif
ifp->if_ierrors++;
return;
}
/* Pull packet off interface. */
m = lance_get(sc, boff, len);
if (m == 0) {
ifp->if_ierrors++;
return;
}
eh = mtod(m, struct ether_header *);
#ifdef LANCE_REVC_BUG
/*
* The old LANCE (Rev. C) chips have a bug which causes
* garbage to be inserted in front of the received packet.
* The work-around is to ignore packets with an invalid
* destination address (garbage will usually not match).
* Of course, this precludes multicast support...
*/
if (ETHER_CMP(eh->ether_dhost, sc->sc_enaddr) &&
ETHER_CMP(eh->ether_dhost, bcast_enaddr)) {
m_freem(m);
return;
}
#endif
/*
* Some lance device does not present IFF_SIMPLEX behavior on multicast
* packets. Make sure to drop it if it is from ourselves.
*/
if (!ETHER_CMP(eh->ether_shost, sc->sc_enaddr)) {
m_freem(m);
return;
}
/* Pass the packet up. */
if_percpuq_enqueue(ifp->if_percpuq, m);
}
#undef ifp
void
lance_watchdog(struct ifnet *ifp)
{
struct lance_softc *sc = ifp->if_softc;
log(LOG_ERR, "%s: device timeout\n", device_xname(sc->sc_dev));
++ifp->if_oerrors;
lance_reset(sc);
}
int
lance_mediachange(struct ifnet *ifp)
{
struct lance_softc *sc = ifp->if_softc;
if (sc->sc_mediachange)
return ((*sc->sc_mediachange)(sc));
return (0);
}
void
lance_mediastatus(struct ifnet *ifp, struct ifmediareq *ifmr)
{
struct lance_softc *sc = ifp->if_softc;
if ((ifp->if_flags & IFF_UP) == 0)
return;
ifmr->ifm_status = IFM_AVALID;
if (sc->sc_havecarrier)
ifmr->ifm_status |= IFM_ACTIVE;
if (sc->sc_mediastatus)
(*sc->sc_mediastatus)(sc, ifmr);
}
/*
* Process an ioctl request.
*/
int
lance_ioctl(struct ifnet *ifp, u_long cmd, void *data)
{
struct lance_softc *sc = ifp->if_softc;
struct ifreq *ifr = (struct ifreq *)data;
int s, error = 0;
s = splnet();
switch (cmd) {
case SIOCGIFMEDIA:
case SIOCSIFMEDIA:
error = ifmedia_ioctl(ifp, ifr, &sc->sc_media, cmd);
break;
default:
if ((error = ether_ioctl(ifp, cmd, data)) != ENETRESET)
break;
error = 0;
if (cmd != SIOCADDMULTI && cmd != SIOCDELMULTI)
break;
if (ifp->if_flags & IFF_RUNNING) {
/*
* Multicast list has changed; set the hardware filter
* accordingly.
*/
lance_reset(sc);
}
break;
}
splx(s);
return (error);
}
hide bool
lance_shutdown(device_t self, int howto)
{
struct lance_softc *sc = device_private(self);
struct ifnet *ifp = &sc->sc_ethercom.ec_if;
lance_stop(ifp, 0);
return true;
}
/*
* Set up the logical address filter.
*/
void
lance_setladrf(struct ethercom *ac, uint16_t *af)
{
struct ifnet *ifp = &ac->ec_if;
struct ether_multi *enm;
uint32_t crc;
struct ether_multistep step;
/*
* Set up multicast address filter by passing all multicast addresses
* through a crc generator, and then using the high order 6 bits as an
* index into the 64 bit logical address filter. The high order bit
* selects the word, while the rest of the bits select the bit within
* the word.
*/
if (ifp->if_flags & IFF_PROMISC)
goto allmulti;
af[0] = af[1] = af[2] = af[3] = 0x0000;
ETHER_FIRST_MULTI(step, ac, enm);
while (enm != NULL) {
if (ETHER_CMP(enm->enm_addrlo, enm->enm_addrhi)) {
/*
* We must listen to a range of multicast addresses.
* For now, just accept all multicasts, rather than
* trying to set only those filter bits needed to match
* the range. (At this time, the only use of address
* ranges is for IP multicast routing, for which the
* range is big enough to require all bits set.)
*/
goto allmulti;
}
crc = ether_crc32_le(enm->enm_addrlo, ETHER_ADDR_LEN);
/* Just want the 6 most significant bits. */
crc >>= 26;
/* Set the corresponding bit in the filter. */
af[crc >> 4] |= 1 << (crc & 0xf);
ETHER_NEXT_MULTI(step, enm);
}
ifp->if_flags &= ~IFF_ALLMULTI;
return;
allmulti:
ifp->if_flags |= IFF_ALLMULTI;
af[0] = af[1] = af[2] = af[3] = 0xffff;
}
/*
* Routines for accessing the transmit and receive buffers.
* The various CPU and adapter configurations supported by this
* driver require three different access methods for buffers
* and descriptors:
* (1) contig (contiguous data; no padding),
* (2) gap2 (two bytes of data followed by two bytes of padding),
* (3) gap16 (16 bytes of data followed by 16 bytes of padding).
*/
/*
* contig: contiguous data with no padding.
*
* Buffers may have any alignment.
*/
void
lance_copytobuf_contig(struct lance_softc *sc, void *from, int boff, int len)
{
uint8_t *buf = sc->sc_mem;
/*
* Just call memcpy() to do the work.
*/
memcpy(buf + boff, from, len);
}
void
lance_copyfrombuf_contig(struct lance_softc *sc, void *to, int boff, int len)
{
uint8_t *buf = sc->sc_mem;
/*
* Just call memcpy() to do the work.
*/
memcpy(to, buf + boff, len);
}
void
lance_zerobuf_contig(struct lance_softc *sc, int boff, int len)
{
uint8_t *buf = sc->sc_mem;
/*
* Just let memset() do the work
*/
memset(buf + boff, 0, len);
}
#if 0
/*
* Examples only; duplicate these and tweak (if necessary) in
* machine-specific front-ends.
*/
/*
* gap2: two bytes of data followed by two bytes of pad.
*
* Buffers must be 4-byte aligned. The code doesn't worry about
* doing an extra byte.
*/
void
lance_copytobuf_gap2(struct lance_softc *sc, void *fromv, int boff, int len)
{
volatile void *buf = sc->sc_mem;
void *from = fromv;
volatile uint16_t *bptr;
if (boff & 0x1) {
/* handle unaligned first byte */
bptr = ((volatile uint16_t *)buf) + (boff - 1);
*bptr = (*from++ << 8) | (*bptr & 0xff);
bptr += 2;
len--;
} else
bptr = ((volatile uint16_t *)buf) + boff;
while (len > 1) {
*bptr = (from[1] << 8) | (from[0] & 0xff);
bptr += 2;
from += 2;
len -= 2;
}
if (len == 1)
*bptr = (uint16_t)*from;
}
void
lance_copyfrombuf_gap2(struct lance_softc *sc, void *tov, int boff, int len)
{
volatile void *buf = sc->sc_mem;
void *to = tov;
volatile uint16_t *bptr;
uint16_t tmp;
if (boff & 0x1) {
/* handle unaligned first byte */
bptr = ((volatile uint16_t *)buf) + (boff - 1);
*to++ = (*bptr >> 8) & 0xff;
bptr += 2;
len--;
} else
bptr = ((volatile uint16_t *)buf) + boff;
while (len > 1) {
tmp = *bptr;
*to++ = tmp & 0xff;
*to++ = (tmp >> 8) & 0xff;
bptr += 2;
len -= 2;
}
if (len == 1)
*to = *bptr & 0xff;
}
void
lance_zerobuf_gap2(struct lance_softc *sc, int boff, int len)
{
volatile void *buf = sc->sc_mem;
volatile uint16_t *bptr;
if ((unsigned int)boff & 0x1) {
bptr = ((volatile uint16_t *)buf) + (boff - 1);
*bptr &= 0xff;
bptr += 2;
len--;
} else
bptr = ((volatile uint16_t *)buf) + boff;
while (len > 0) {
*bptr = 0;
bptr += 2;
len -= 2;
}
}
/*
* gap16: 16 bytes of data followed by 16 bytes of pad.
*
* Buffers must be 32-byte aligned.
*/
void
lance_copytobuf_gap16(struct lance_softc *sc, void *fromv, int boff, int len)
{
volatile uint8_t *buf = sc->sc_mem;
void *from = fromv;
uint8_t *bptr;
int xfer;
bptr = buf + ((boff << 1) & ~0x1f);
boff &= 0xf;
xfer = uimin(len, 16 - boff);
while (len > 0) {
memcpy(bptr + boff, from, xfer);
from += xfer;
bptr += 32;
boff = 0;
len -= xfer;
xfer = uimin(len, 16);
}
}
void
lance_copyfrombuf_gap16(struct lance_softc *sc, void *tov, int boff, int len)
{
volatile uint8_t *buf = sc->sc_mem;
void *to = tov;
uint8_t *bptr;
int xfer;
bptr = buf + ((boff << 1) & ~0x1f);
boff &= 0xf;
xfer = uimin(len, 16 - boff);
while (len > 0) {
memcpy(to, bptr + boff, xfer);
to += xfer;
bptr += 32;
boff = 0;
len -= xfer;
xfer = uimin(len, 16);
}
}
void
lance_zerobuf_gap16(struct lance_softc *sc, int boff, int len)
{
volatile uint8_t *buf = sc->sc_mem;
uint8_t *bptr;
int xfer;
bptr = buf + ((boff << 1) & ~0x1f);
boff &= 0xf;
xfer = uimin(len, 16 - boff);
while (len > 0) {
memset(bptr + boff, 0, xfer);
bptr += 32;
boff = 0;
len -= xfer;
xfer = uimin(len, 16);
}
}
#endif /* Example only */