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      1 /*	$NetBSD: fec.c,v 1.2 2026/06/30 21:31:31 rkujawa Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2008, 2026 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Radoslaw Kujawa and Robert Swindells.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 /*
     33  * Driver for the MPC5200B Fast Ethernet Controller (FEC).
     34  */
     35 
     36 #include <sys/cdefs.h>
     37 __KERNEL_RCSID(0, "$NetBSD: fec.c,v 1.2 2026/06/30 21:31:31 rkujawa Exp $");
     38 
     39 #include <sys/param.h>
     40 #include <sys/systm.h>
     41 #include <sys/device.h>
     42 #include <sys/callout.h>
     43 #include <sys/mbuf.h>
     44 #include <sys/bus.h>
     45 
     46 #include <net/if.h>
     47 #include <net/if_dl.h>
     48 #include <net/if_ether.h>
     49 #include <net/if_media.h>
     50 #include <net/bpf.h>
     51 
     52 #include <dev/mii/mii.h>
     53 #include <dev/mii/miivar.h>
     54 
     55 #include <dev/ofw/openfirm.h>
     56 
     57 #include <machine/autoconf.h>
     58 
     59 #include <powerpc/mpc5200/obiovar.h>
     60 #include <powerpc/mpc5200/mpc5200reg.h>
     61 #include <powerpc/mpc5200/fecreg.h>
     62 #include <powerpc/mpc5200/fecvar.h>
     63 #include <powerpc/mpc5200/cdmvar.h>
     64 #include <powerpc/mpc5200/bestcommvar.h>
     65 
     66 #define	FEC_READ(sc, r)		bus_space_read_4((sc)->sc_iot, (sc)->sc_ioh, (r))
     67 #define	FEC_WRITE(sc, r, v)	bus_space_write_4((sc)->sc_iot, (sc)->sc_ioh, (r), (v))
     68 
     69 #define	FEC_RX_TASK		3	/* TASK_FEC_RX image slot	*/
     70 #define	FEC_TX_TASK		2	/* TASK_FEC_TX image slot	*/
     71 #define	FEC_RX_INITIATOR	3	/* INITIATOR_FEC_RX		*/
     72 #define	FEC_TX_INITIATOR	4	/* INITIATOR_FEC_TX		*/
     73 
     74 static const struct bestcomm_bd_layout fec_rx_layout = BESTCOMM_LAYOUT_FEC_RX;
     75 static const struct bestcomm_bd_layout fec_tx_layout = BESTCOMM_LAYOUT_FEC_TX;
     76 
     77 static int	fec_match(device_t, cfdata_t, void *);
     78 static void	fec_attach(device_t, device_t, void *);
     79 
     80 static int	fec_miibus_readreg(device_t, int, int, uint16_t *);
     81 static int	fec_miibus_writereg(device_t, int, int, uint16_t);
     82 static void	fec_miibus_statchg(struct ifnet *);
     83 
     84 static int	fec_ioctl(struct ifnet *, u_long, void *);
     85 static int	fec_init(struct ifnet *);
     86 static void	fec_stop(struct ifnet *, int);
     87 static void	fec_start(struct ifnet *);
     88 static void	fec_tick(void *);
     89 
     90 static void	fec_reset(struct fec_softc *);
     91 static void	fec_mac_setup(struct fec_softc *);
     92 static void	fec_set_filter(struct fec_softc *);
     93 static void	fec_mib_sync(struct fec_softc *, bool);
     94 static int	fec_newbuf(struct fec_softc *, u_int);
     95 static int	fec_intr(void *);
     96 static int	fec_rxintr(void *);
     97 static int	fec_txintr(void *);
     98 
     99 CFATTACH_DECL_NEW(fec, sizeof(struct fec_softc),
    100     fec_match, fec_attach, NULL, NULL);
    101 
    102 static int
    103 fec_match(device_t parent, cfdata_t cf, void *aux)
    104 {
    105 	struct obio_attach_args *oba = aux;
    106 	char compat[40];
    107 	int len;
    108 
    109 	if (strcmp(oba->obio_name, "ethernet") == 0)
    110 		return 1;
    111 
    112 	len = OF_getprop(oba->obio_node, "compatible", compat, sizeof(compat));
    113 	if (len > 0 &&
    114 	    (strcmp(compat, "mpc5200-fec") == 0 ||
    115 	     strcmp(compat, "mpc5200b-fec") == 0))
    116 		return 1;
    117 
    118 	return 0;
    119 }
    120 
    121 static void
    122 fec_attach(device_t parent, device_t self, void *aux)
    123 {
    124 	struct fec_softc *sc = device_private(self);
    125 	struct obio_attach_args *oba = aux;
    126 	struct ifnet *ifp = &sc->sc_if;
    127 	struct mii_data *mii = &sc->sc_mii;
    128 	uint8_t enaddr[ETHER_ADDR_LEN];
    129 	bus_size_t size;
    130 	int ist;
    131 
    132 	sc->sc_dev = self;
    133 	sc->sc_iot = oba->obio_bst;
    134 	sc->sc_dmat = oba->obio_dmat;
    135 	sc->sc_pa = oba->obio_addr;
    136 	callout_init(&sc->sc_tick_ch, 0);
    137 	callout_setfunc(&sc->sc_tick_ch, fec_tick, sc);
    138 
    139 	size = oba->obio_size != 0 ? oba->obio_size : FEC_REG_SIZE;
    140 	if (bus_space_map(sc->sc_iot, oba->obio_addr, size, 0,
    141 	    &sc->sc_ioh) != 0) {
    142 		aprint_error(": can't map registers\n");
    143 		return;
    144 	}
    145 
    146 	if (OF_getprop(oba->obio_node, "local-mac-address", enaddr,
    147 	    sizeof(enaddr)) != sizeof(enaddr) &&
    148 	    OF_getprop(oba->obio_node, "mac-address", enaddr,
    149 	    sizeof(enaddr)) != sizeof(enaddr)) {
    150 		aprint_error(": no MAC address\n");
    151 		return;
    152 	}
    153 	memcpy(sc->sc_enaddr, enaddr, ETHER_ADDR_LEN);
    154 
    155 	if (obio_decode_interrupt(oba->obio_node, 0, &sc->sc_irq, &ist))
    156 		sc->sc_ih = intr_establish(sc->sc_irq, ist, IPL_NET,
    157 		    fec_intr, sc);
    158 
    159 	aprint_normal(": MPC5200 FEC, address %s\n",
    160 	    ether_sprintf(sc->sc_enaddr));
    161 
    162 	/* Reset the controller and program the MII management clock. */
    163 	sc->sc_ipb_freq = mpc5200_cdm_get_ipb_freq();
    164 	fec_reset(sc);
    165 
    166 	/* MII / PHY. */
    167 	mii->mii_ifp = ifp;
    168 	mii->mii_readreg = fec_miibus_readreg;
    169 	mii->mii_writereg = fec_miibus_writereg;
    170 	mii->mii_statchg = fec_miibus_statchg;
    171 	sc->sc_ec.ec_mii = mii;
    172 	ifmedia_init(&mii->mii_media, 0, ether_mediachange, ether_mediastatus);
    173 	/* MIIF_DOPAUSE: advertise 802.3 PAUSE so we can honour rx flow control. */
    174 	mii_attach(self, mii, 0xffffffff, MII_PHY_ANY, MII_OFFSET_ANY,
    175 	    MIIF_DOPAUSE);
    176 	if (LIST_FIRST(&mii->mii_phys) == NULL) {
    177 		aprint_error_dev(self, "no PHY found\n");
    178 		ifmedia_add(&mii->mii_media, IFM_ETHER | IFM_MANUAL, 0, NULL);
    179 		ifmedia_set(&mii->mii_media, IFM_ETHER | IFM_MANUAL);
    180 	} else
    181 		ifmedia_set(&mii->mii_media, IFM_ETHER | IFM_AUTO);
    182 
    183 	/* The controller accepts VLAN-sized frames (see fec_mac_setup()). */
    184 	sc->sc_ec.ec_capabilities |= ETHERCAP_VLAN_MTU;
    185 
    186 	strlcpy(ifp->if_xname, device_xname(self), IFNAMSIZ);
    187 	ifp->if_softc = sc;
    188 	ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST;
    189 	ifp->if_init = fec_init;
    190 	ifp->if_stop = fec_stop;
    191 	ifp->if_start = fec_start;
    192 	ifp->if_ioctl = fec_ioctl;
    193 	IFQ_SET_READY(&ifp->if_snd);
    194 
    195 	if_attach(ifp);
    196 	if_deferred_start_init(ifp, NULL);
    197 	ether_ifattach(ifp, sc->sc_enaddr);
    198 }
    199 
    200 /*
    201  * Soft-reset the controller and set the MII management clock divider so MDC
    202  * stays at or below 2.5 MHz, derived from the IPB clock.
    203  */
    204 static void
    205 fec_reset(struct fec_softc *sc)
    206 {
    207 	uint32_t div;
    208 	int i;
    209 
    210 	FEC_WRITE(sc, FEC_ECNTRL, FEC_ECNTRL_RESET);
    211 	for (i = 0; i < 1000; i++) {
    212 		if ((FEC_READ(sc, FEC_ECNTRL) & FEC_ECNTRL_RESET) == 0)
    213 			break;
    214 		DELAY(10);
    215 	}
    216 	FEC_WRITE(sc, FEC_IMASK, 0);			/* mask all events */
    217 	FEC_WRITE(sc, FEC_IEVENT, 0xffffffff);		/* clear events	 */
    218 
    219 	div = howmany(sc->sc_ipb_freq, 2 * FEC_MII_MAX_CLK);
    220 	if (div > 0x3f)
    221 		div = 0x3f;
    222 	FEC_WRITE(sc, FEC_MII_SPEED, FEC_MII_SPEED_DIV(div));
    223 }
    224 
    225 static int
    226 fec_mii_wait(struct fec_softc *sc)
    227 {
    228 	int i;
    229 
    230 	for (i = 0; i < FEC_PHY_TIMEOUT; i++) {
    231 		if (FEC_READ(sc, FEC_IEVENT) & FEC_INT_MII) {
    232 			FEC_WRITE(sc, FEC_IEVENT, FEC_INT_MII);
    233 			return 0;
    234 		}
    235 		DELAY(10);
    236 	}
    237 	return ETIMEDOUT;
    238 }
    239 
    240 static int
    241 fec_miibus_readreg(device_t self, int phy, int reg, uint16_t *val)
    242 {
    243 	struct fec_softc *sc = device_private(self);
    244 
    245 	FEC_WRITE(sc, FEC_IEVENT, FEC_INT_MII);
    246 	FEC_WRITE(sc, FEC_MII_DATA, FEC_MII_READ(phy, reg));
    247 	if (fec_mii_wait(sc) != 0)
    248 		return ETIMEDOUT;
    249 
    250 	*val = FEC_READ(sc, FEC_MII_DATA) & FEC_MII_DATA_MASK;
    251 	return 0;
    252 }
    253 
    254 static int
    255 fec_miibus_writereg(device_t self, int phy, int reg, uint16_t val)
    256 {
    257 	struct fec_softc *sc = device_private(self);
    258 
    259 	FEC_WRITE(sc, FEC_IEVENT, FEC_INT_MII);
    260 	FEC_WRITE(sc, FEC_MII_DATA, FEC_MII_WRITE(phy, reg, val));
    261 	return fec_mii_wait(sc);
    262 }
    263 
    264 static void
    265 fec_miibus_statchg(struct ifnet *ifp)
    266 {
    267 	struct fec_softc *sc = ifp->if_softc;
    268 	uint32_t xcr, rcr;
    269 
    270 	xcr = FEC_READ(sc, FEC_X_CNTRL);
    271 	if (sc->sc_mii.mii_media_active & IFM_FDX)
    272 		xcr |= FEC_X_CNTRL_FDEN;
    273 	else
    274 		xcr &= ~FEC_X_CNTRL_FDEN;
    275 	FEC_WRITE(sc, FEC_X_CNTRL, xcr);
    276 
    277 	rcr = FEC_READ(sc, FEC_R_CNTRL);
    278 	if (sc->sc_mii.mii_media_active & IFM_ETH_RXPAUSE)
    279 		rcr |= FEC_R_CNTRL_FCE;
    280 	else
    281 		rcr &= ~FEC_R_CNTRL_FCE;
    282 	FEC_WRITE(sc, FEC_R_CNTRL, rcr);
    283 }
    284 
    285 static void
    286 fec_tick(void *arg)
    287 {
    288 	struct fec_softc *sc = arg;
    289 	int s;
    290 
    291 	s = splnet();
    292 	mii_tick(&sc->sc_mii);
    293 	if (sc->sc_if.if_flags & IFF_RUNNING)
    294 		fec_mib_sync(sc, false);	/* fold hw counters into if_stats */
    295 	splx(s);
    296 
    297 	/*
    298 	 * Meh. Under load the receive FIFO can overrun, work it around.
    299 	 */
    300 	if ((sc->sc_if.if_flags & IFF_RUNNING) &&
    301 	    (FEC_READ(sc, FEC_ECNTRL) & FEC_ECNTRL_ETHER_EN) == 0) {
    302 		if_statinc(&sc->sc_if, if_ierrors);
    303 		aprint_error_dev(sc->sc_dev,
    304 		    "ETHER_EN cleared, resetting\n");
    305 		s = splnet();
    306 		(void)fec_init(&sc->sc_if);	/* reschedules the callout */
    307 		splx(s);
    308 		return;
    309 	}
    310 
    311 	callout_schedule(&sc->sc_tick_ch, hz);
    312 }
    313 
    314 /* Program the station address and receive/transmit MAC control. */
    315 static void
    316 fec_mac_setup(struct fec_softc *sc)
    317 {
    318 	FEC_WRITE(sc, FEC_PADDR1,
    319 	    (sc->sc_enaddr[0] << 24) | (sc->sc_enaddr[1] << 16) |
    320 	    (sc->sc_enaddr[2] << 8) | sc->sc_enaddr[3]);
    321 	FEC_WRITE(sc, FEC_PADDR2,
    322 	    (sc->sc_enaddr[4] << 24) | (sc->sc_enaddr[5] << 16) | 0x8808);
    323 	FEC_WRITE(sc, FEC_IADDR1, 0);
    324 	FEC_WRITE(sc, FEC_IADDR2, 0);
    325 	/*
    326 	 * Allow VLAN-tagged frames (ETHERCAP_VLAN_MTU)
    327 	 */
    328 	FEC_WRITE(sc, FEC_R_CNTRL,
    329 	    FEC_R_CNTRL_MAX_FL(ETHER_MAX_LEN + ETHER_VLAN_ENCAP_LEN) |
    330 	    FEC_R_CNTRL_MII_MODE);
    331 	FEC_WRITE(sc, FEC_X_CNTRL, FEC_X_CNTRL_FDEN);
    332 
    333 	/*
    334 	 * Enable frame mode on both FIFOs
    335 	 */
    336 	FEC_WRITE(sc, FEC_RESET_CNTRL, FEC_RESET_CNTRL_FIFO_EN);
    337 
    338 	FEC_WRITE(sc, FEC_RFIFO_CONTROL, FEC_FIFO_CTRL_INIT);
    339 	FEC_WRITE(sc, FEC_TFIFO_CONTROL, FEC_FIFO_CTRL_INIT);
    340 
    341 	/*
    342 	 * The transmit FIFO requests data from BestComm only while it holds
    343 	 * fewer than "alarm" bytes!
    344 	 */
    345 	FEC_WRITE(sc, FEC_TFIFO_ALARM, 0x80);
    346 }
    347 
    348 /*
    349  * Program the receive address filter
    350  */
    351 static void
    352 fec_set_filter(struct fec_softc *sc)
    353 {
    354 	struct ethercom *ec = &sc->sc_ec;
    355 	struct ifnet *ifp = &sc->sc_if;
    356 	struct ether_multi *enm;
    357 	struct ether_multistep step;
    358 	uint32_t gaddr[2] = { 0, 0 };
    359 	uint32_t rcr;
    360 	u_int h;
    361 
    362 	rcr = FEC_READ(sc, FEC_R_CNTRL) & ~FEC_R_CNTRL_PROM;
    363 
    364 	if (ifp->if_flags & IFF_PROMISC) {
    365 		rcr |= FEC_R_CNTRL_PROM;
    366 		gaddr[0] = gaddr[1] = 0xffffffff;
    367 		goto done;
    368 	}
    369 
    370 	ETHER_LOCK(ec);
    371 	ec->ec_flags &= ~ETHER_F_ALLMULTI;
    372 	ETHER_FIRST_MULTI(step, ec, enm);
    373 	while (enm != NULL) {
    374 		if (memcmp(enm->enm_addrlo, enm->enm_addrhi,
    375 		    ETHER_ADDR_LEN) != 0) {
    376 			/*
    377 			 * A range of addresses
    378 			 */
    379 			ec->ec_flags |= ETHER_F_ALLMULTI;
    380 			gaddr[0] = gaddr[1] = 0xffffffff;
    381 			break;
    382 		}
    383 		h = ether_crc32_le(enm->enm_addrlo, ETHER_ADDR_LEN) >> 26;
    384 		gaddr[h >> 5] |= 1U << (h & 0x1f);
    385 		ETHER_NEXT_MULTI(step, enm);
    386 	}
    387 	ETHER_UNLOCK(ec);
    388 
    389 done:
    390 	FEC_WRITE(sc, FEC_GADDR1, gaddr[1]);	/* buckets 32..63 */
    391 	FEC_WRITE(sc, FEC_GADDR2, gaddr[0]);	/* buckets  0..31 */
    392 	FEC_WRITE(sc, FEC_R_CNTRL, rcr);
    393 }
    394 
    395 /*
    396  * On-chip counters we dump into the interface stats.
    397  */
    398 static const struct fec_mibcnt {
    399 	bus_size_t	reg;
    400 	if_stat_t	stat;
    401 } fec_mibtab[] = {
    402 	{ FEC_RMON_T_COL,    if_collisions },
    403 	{ FEC_IEEE_T_LCOL,   if_oerrors },
    404 	{ FEC_IEEE_T_EXCOL,  if_oerrors },
    405 	{ FEC_IEEE_T_MACERR, if_oerrors },	/* Tx FIFO underrun	*/
    406 	{ FEC_IEEE_R_DROP,   if_iqdrops },
    407 	{ FEC_IEEE_R_CRC,    if_ierrors },
    408 	{ FEC_IEEE_R_ALIGN,  if_ierrors },
    409 	{ FEC_IEEE_R_MACERR, if_iqdrops },	/* Rx FIFO overflow	*/
    410 };
    411 __CTASSERT(__arraycount(fec_mibtab) == FEC_NMIB);
    412 
    413 /*
    414  * Harvest the on-chip MIB counters.
    415  */
    416 static void
    417 fec_mib_sync(struct fec_softc *sc, bool prime)
    418 {
    419 	struct ifnet *ifp = &sc->sc_if;
    420 	net_stat_ref_t nsr;
    421 	u_int i;
    422 
    423 	if (prime) {
    424 		for (i = 0; i < FEC_NMIB; i++)
    425 			sc->sc_mib_prev[i] = FEC_READ(sc, fec_mibtab[i].reg);
    426 		return;
    427 	}
    428 
    429 	nsr = IF_STAT_GETREF(ifp);
    430 	for (i = 0; i < FEC_NMIB; i++) {
    431 		uint32_t cur = FEC_READ(sc, fec_mibtab[i].reg);
    432 		uint32_t delta = cur - sc->sc_mib_prev[i];	/* wraps mod 2^32 */
    433 
    434 		if (delta != 0)
    435 			if_statadd_ref(ifp, nsr, fec_mibtab[i].stat, delta);
    436 		sc->sc_mib_prev[i] = cur;
    437 	}
    438 	IF_STAT_PUTREF(ifp);
    439 }
    440 
    441 /* Allocate a cluster for receive descriptor idx and hand it to the engine. */
    442 static int
    443 fec_newbuf(struct fec_softc *sc, u_int idx)
    444 {
    445 	struct mbuf *m;
    446 	int error;
    447 
    448 	MGETHDR(m, M_DONTWAIT, MT_DATA);
    449 	if (m == NULL)
    450 		return ENOBUFS;
    451 	MCLGET(m, M_DONTWAIT);
    452 	if ((m->m_flags & M_EXT) == 0) {
    453 		m_freem(m);
    454 		return ENOBUFS;
    455 	}
    456 	m->m_len = m->m_pkthdr.len = MCLBYTES;
    457 	error = bus_dmamap_load_mbuf(sc->sc_dmat, sc->sc_rxmap[idx], m,
    458 	    BUS_DMA_NOWAIT | BUS_DMA_READ);
    459 	if (error) {
    460 		m_freem(m);
    461 		return error;
    462 	}
    463 	bus_dmamap_sync(sc->sc_dmat, sc->sc_rxmap[idx], 0, MCLBYTES,
    464 	    BUS_DMASYNC_PREREAD);
    465 	sc->sc_rxmbuf[idx] = m;
    466 	bestcomm_bd_post(&sc->sc_rxring, idx,
    467 	    sc->sc_rxmap[idx]->dm_segs[0].ds_addr, MCLBYTES, 0);
    468 	return 0;
    469 }
    470 
    471 static int
    472 fec_init(struct ifnet *ifp)
    473 {
    474 	struct fec_softc *sc = ifp->if_softc;
    475 	u_int i;
    476 	int error;
    477 	bool link_up;
    478 
    479 	link_up = (sc->sc_mii.mii_media_status & IFM_ACTIVE) != 0;
    480 
    481 	fec_stop(ifp, 0);
    482 
    483 	if (!bestcomm_available()) {
    484 		aprint_error_ifnet(ifp, "BestComm SDMA not available\n");
    485 		return ENXIO;
    486 	}
    487 
    488 	fec_reset(sc);
    489 	fec_mac_setup(sc);
    490 	fec_set_filter(sc);
    491 
    492 	/*
    493 	 * Enable the on-chip MIB counter block
    494 	 */
    495 	FEC_WRITE(sc, FEC_MIB_CONTROL, 0);
    496 	fec_mib_sync(sc, true);
    497 
    498 	if (bestcomm_bd_setup(&sc->sc_rxring, FEC_RX_TASK, &fec_rx_layout,
    499 	    sc->sc_pa + FEC_RFIFO_DATA, FEC_NRXDESC, MCLBYTES, 4,
    500 	    FEC_RX_INITIATOR, 6) != 0 ||
    501 	    bestcomm_bd_setup(&sc->sc_txring, FEC_TX_TASK, &fec_tx_layout,
    502 	    sc->sc_pa + FEC_TFIFO_DATA, FEC_NTXDESC, MCLBYTES, 4,
    503 	    FEC_TX_INITIATOR, 5) != 0) {
    504 		aprint_error_ifnet(ifp, "cannot set up SDMA rings\n");
    505 		error = ENOMEM;
    506 		goto fail;
    507 	}
    508 
    509 	for (i = 0; i < FEC_NRXDESC; i++) {
    510 		if (sc->sc_rxmap[i] == NULL &&
    511 		    bus_dmamap_create(sc->sc_dmat, MCLBYTES, 1, MCLBYTES, 0,
    512 		    BUS_DMA_NOWAIT, &sc->sc_rxmap[i]) != 0) {
    513 			error = ENOMEM;
    514 			goto fail;
    515 		}
    516 		if ((error = fec_newbuf(sc, i)) != 0)
    517 			goto fail;
    518 	}
    519 	for (i = 0; i < FEC_NTXDESC; i++) {
    520 		if (sc->sc_txmap[i] == NULL &&
    521 		    bus_dmamap_create(sc->sc_dmat, MCLBYTES, 1, MCLBYTES, 0,
    522 		    BUS_DMA_NOWAIT, &sc->sc_txmap[i]) != 0) {
    523 			error = ENOMEM;
    524 			goto fail;
    525 		}
    526 	}
    527 	sc->sc_rxptr = 0;
    528 	sc->sc_txnext = sc->sc_txdirty = sc->sc_txbusy = 0;
    529 
    530 	/* Hook the BestComm task-completion interrupts (via the SIU cascade). */
    531 	sc->sc_rxih = intr_establish(bestcomm_task_irq(FEC_RX_TASK), IST_LEVEL,
    532 	    IPL_NET, fec_rxintr, sc);
    533 	sc->sc_txih = intr_establish(bestcomm_task_irq(FEC_TX_TASK), IST_LEVEL,
    534 	    IPL_NET, fec_txintr, sc);
    535 
    536 	/*
    537 	 * Bring the link up before enabling the controller.
    538 	 */
    539 	mii_mediachg(&sc->sc_mii);
    540 	if (!link_up) {
    541 		for (i = 0; i < 500; i++) {
    542 			mii_pollstat(&sc->sc_mii);
    543 			if (sc->sc_mii.mii_media_status & IFM_ACTIVE)
    544 				break;
    545 			DELAY(10000);
    546 		}
    547 	}
    548 
    549 	FEC_WRITE(sc, FEC_ECNTRL, FEC_ECNTRL_ETHER_EN);
    550 	bestcomm_task_start(FEC_RX_TASK);
    551 	bestcomm_task_start(FEC_TX_TASK);
    552 
    553 	ifp->if_flags |= IFF_RUNNING;
    554 	ifp->if_flags &= ~IFF_OACTIVE;
    555 
    556 	callout_schedule(&sc->sc_tick_ch, hz);
    557 	return 0;
    558 
    559 fail:
    560 	/* Unwind any partial setup so we leave a clean, fully-stopped state. */
    561 	fec_stop(ifp, 1);
    562 	return error;
    563 }
    564 
    565 static void
    566 fec_stop(struct ifnet *ifp, int disable)
    567 {
    568 	struct fec_softc *sc = ifp->if_softc;
    569 	u_int i;
    570 
    571 	callout_stop(&sc->sc_tick_ch);
    572 
    573 	/*
    574 	 * Stop the SDMA tasks and release their buffer-descriptor rings back
    575 	 * to the on-chip SRAM pool.
    576 	 */
    577 	bestcomm_bd_teardown(&sc->sc_rxring);
    578 	bestcomm_bd_teardown(&sc->sc_txring);
    579 
    580 	FEC_WRITE(sc, FEC_ECNTRL, 0);
    581 
    582 	if (sc->sc_rxih != NULL) {
    583 		intr_disestablish(sc->sc_rxih);
    584 		sc->sc_rxih = NULL;
    585 	}
    586 	if (sc->sc_txih != NULL) {
    587 		intr_disestablish(sc->sc_txih);
    588 		sc->sc_txih = NULL;
    589 	}
    590 
    591 	mii_down(&sc->sc_mii);
    592 
    593 	for (i = 0; i < FEC_NRXDESC; i++) {
    594 		if (sc->sc_rxmbuf[i] != NULL) {
    595 			bus_dmamap_unload(sc->sc_dmat, sc->sc_rxmap[i]);
    596 			m_freem(sc->sc_rxmbuf[i]);
    597 			sc->sc_rxmbuf[i] = NULL;
    598 		}
    599 	}
    600 	for (i = 0; i < FEC_NTXDESC; i++) {
    601 		if (sc->sc_txmbuf[i] != NULL) {
    602 			bus_dmamap_unload(sc->sc_dmat, sc->sc_txmap[i]);
    603 			m_freem(sc->sc_txmbuf[i]);
    604 			sc->sc_txmbuf[i] = NULL;
    605 		}
    606 	}
    607 	ifp->if_flags &= ~(IFF_RUNNING | IFF_OACTIVE);
    608 }
    609 
    610 static void
    611 fec_start(struct ifnet *ifp)
    612 {
    613 	struct fec_softc *sc = ifp->if_softc;
    614 	struct mbuf *m, *mn;
    615 	u_int idx;
    616 	int error, posted = 0;
    617 
    618 	if ((ifp->if_flags & (IFF_RUNNING | IFF_OACTIVE)) != IFF_RUNNING)
    619 		return;
    620 
    621 	while (sc->sc_txbusy < FEC_NTXDESC) {
    622 		IFQ_POLL(&ifp->if_snd, m);
    623 		if (m == NULL)
    624 			break;
    625 		idx = sc->sc_txnext;
    626 
    627 		error = bus_dmamap_load_mbuf(sc->sc_dmat, sc->sc_txmap[idx], m,
    628 		    BUS_DMA_NOWAIT | BUS_DMA_WRITE);
    629 		if (error == EFBIG) {
    630 			/* The buffer descriptor holds one segment; collapse. */
    631 			mn = m_defrag(m, M_DONTWAIT);
    632 			if (mn != NULL) {
    633 				m = mn;
    634 				error = bus_dmamap_load_mbuf(sc->sc_dmat,
    635 				    sc->sc_txmap[idx], m,
    636 				    BUS_DMA_NOWAIT | BUS_DMA_WRITE);
    637 			}
    638 		}
    639 		IFQ_DEQUEUE(&ifp->if_snd, m);
    640 		if (error) {
    641 			m_freem(m);
    642 			if_statinc(ifp, if_oerrors);
    643 			continue;
    644 		}
    645 
    646 		bus_dmamap_sync(sc->sc_dmat, sc->sc_txmap[idx], 0,
    647 		    m->m_pkthdr.len, BUS_DMASYNC_PREWRITE);
    648 		bpf_mtap(ifp, m, BPF_D_OUT);
    649 		sc->sc_txmbuf[idx] = m;
    650 		bestcomm_bd_post(&sc->sc_txring, idx,
    651 		    sc->sc_txmap[idx]->dm_segs[0].ds_addr, m->m_pkthdr.len,
    652 		    BESTCOMM_BD_FLAG_LAST | BESTCOMM_BD_FLAG_INT);
    653 		sc->sc_txnext = (idx + 1) % FEC_NTXDESC;
    654 		sc->sc_txbusy++;
    655 		posted = 1;
    656 	}
    657 
    658 	/*
    659 	 * (Re-)enable the transmit task.
    660 	 */
    661 	if (posted)
    662 		bestcomm_task_start(FEC_TX_TASK);
    663 
    664 	if (sc->sc_txbusy == FEC_NTXDESC)
    665 		ifp->if_flags |= IFF_OACTIVE;
    666 }
    667 
    668 /* BestComm FEC_RX task completion: hand received frames up, refill the ring. */
    669 static int
    670 fec_rxintr(void *arg)
    671 {
    672 	struct fec_softc *sc = arg;
    673 	struct ifnet *ifp = &sc->sc_if;
    674 	struct mbuf *m;
    675 	uint32_t st;
    676 	u_int idx;
    677 	int len, handled = 0;
    678 
    679 	for (;;) {
    680 		idx = sc->sc_rxptr;
    681 		st = bestcomm_bd_status(&sc->sc_rxring, idx);
    682 		if (st & BESTCOMM_BD_READY)
    683 			break;
    684 		handled = 1;
    685 
    686 		bus_dmamap_sync(sc->sc_dmat, sc->sc_rxmap[idx], 0, MCLBYTES,
    687 		    BUS_DMASYNC_POSTREAD);
    688 		bus_dmamap_unload(sc->sc_dmat, sc->sc_rxmap[idx]);
    689 		m = sc->sc_rxmbuf[idx];
    690 		sc->sc_rxmbuf[idx] = NULL;
    691 
    692 		len = st & BESTCOMM_BD_LEN_MASK;
    693 		if (len > ETHER_CRC_LEN)
    694 			len -= ETHER_CRC_LEN;	/* strip FCS */
    695 
    696 		if (fec_newbuf(sc, idx) != 0) {
    697 			/* No replacement: recycle this buffer, drop the frame. */
    698 			sc->sc_rxmbuf[idx] = m;
    699 			(void)bus_dmamap_load_mbuf(sc->sc_dmat,
    700 			    sc->sc_rxmap[idx], m, BUS_DMA_NOWAIT | BUS_DMA_READ);
    701 			bus_dmamap_sync(sc->sc_dmat, sc->sc_rxmap[idx], 0,
    702 			    MCLBYTES, BUS_DMASYNC_PREREAD);
    703 			bestcomm_bd_post(&sc->sc_rxring, idx,
    704 			    sc->sc_rxmap[idx]->dm_segs[0].ds_addr, MCLBYTES, 0);
    705 			if_statinc(ifp, if_ierrors);
    706 		} else {
    707 			m_set_rcvif(m, ifp);
    708 			m->m_pkthdr.len = m->m_len = len;
    709 			if_percpuq_enqueue(ifp->if_percpuq, m);
    710 		}
    711 		sc->sc_rxptr = (idx + 1) % FEC_NRXDESC;
    712 	}
    713 
    714 	return handled;
    715 }
    716 
    717 /* BestComm FEC_TX task completion: reap transmitted frames. */
    718 static int
    719 fec_txintr(void *arg)
    720 {
    721 	struct fec_softc *sc = arg;
    722 	struct ifnet *ifp = &sc->sc_if;
    723 	uint32_t st;
    724 	u_int idx;
    725 	int handled = 0;
    726 
    727 	while (sc->sc_txbusy > 0) {
    728 		idx = sc->sc_txdirty;
    729 		st = bestcomm_bd_status(&sc->sc_txring, idx);
    730 		if (st & BESTCOMM_BD_READY)
    731 			break;
    732 		handled = 1;
    733 
    734 		bus_dmamap_sync(sc->sc_dmat, sc->sc_txmap[idx], 0,
    735 		    sc->sc_txmbuf[idx]->m_pkthdr.len, BUS_DMASYNC_POSTWRITE);
    736 		bus_dmamap_unload(sc->sc_dmat, sc->sc_txmap[idx]);
    737 		m_freem(sc->sc_txmbuf[idx]);
    738 		sc->sc_txmbuf[idx] = NULL;
    739 		if_statinc(ifp, if_opackets);
    740 
    741 		sc->sc_txdirty = (idx + 1) % FEC_NTXDESC;
    742 		sc->sc_txbusy--;
    743 	}
    744 	if (handled) {
    745 		ifp->if_flags &= ~IFF_OACTIVE;
    746 		if_schedule_deferred_start(ifp);
    747 	}
    748 	return handled;
    749 }
    750 
    751 static int
    752 fec_ioctl(struct ifnet *ifp, u_long cmd, void *data)
    753 {
    754 	struct fec_softc *sc = ifp->if_softc;
    755 	int s, error;
    756 
    757 	s = splnet();
    758 	error = ether_ioctl(ifp, cmd, data);
    759 	if (error == ENETRESET) {
    760 		/*
    761 		 * The multicast list or the promiscuous flag changed.
    762 		 */
    763 		if (ifp->if_flags & IFF_RUNNING)
    764 			fec_set_filter(sc);
    765 		error = 0;
    766 	}
    767 	splx(s);
    768 	return error;
    769 }
    770 
    771 static int
    772 fec_intr(void *arg)
    773 {
    774 	struct fec_softc *sc = arg;
    775 	uint32_t ievent;
    776 
    777 	ievent = FEC_READ(sc, FEC_IEVENT);
    778 	FEC_WRITE(sc, FEC_IEVENT, ievent);	/* acknowledge */
    779 	/* Frame rx/tx is serviced by the BestComm task-completion handlers. */
    780 	return ievent != 0;
    781 }
    782