xref: /freebsd/sys/dev/ffec/if_ffec.c (revision 6a7aa5530c0d860c98c982968ac27728daaac7aa)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2013 Ian Lepore <ian@freebsd.org>
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  *
28  */
29 
30 #include <sys/cdefs.h>
31 /*
32  * Driver for Freescale Fast Ethernet Controller, found on imx-series SoCs among
33  * others.  Also works for the ENET Gigibit controller found on imx6 and imx28,
34  * but the driver doesn't currently use any of the ENET advanced features other
35  * than enabling gigabit.
36  *
37  * The interface name 'fec' is already taken by netgraph's Fast Etherchannel
38  * (netgraph/ng_fec.c), so we use 'ffec'.
39  *
40  * Requires an FDT entry with at least these properties:
41  *   fec: ethernet@02188000 {
42  *      compatible = "fsl,imxNN-fec";
43  *      reg = <0x02188000 0x4000>;
44  *      interrupts = <150 151>;
45  *      phy-mode = "rgmii";
46  *      phy-disable-preamble; // optional
47  *   };
48  * The second interrupt number is for IEEE-1588, and is not currently used; it
49  * need not be present.  phy-mode must be one of: "mii", "rmii", "rgmii".
50  * There is also an optional property, phy-disable-preamble, which if present
51  * will disable the preamble bits, cutting the size of each mdio transaction
52  * (and thus the busy-wait time) in half.
53  */
54 
55 #include <sys/param.h>
56 #include <sys/systm.h>
57 #include <sys/bus.h>
58 #include <sys/endian.h>
59 #include <sys/kernel.h>
60 #include <sys/lock.h>
61 #include <sys/malloc.h>
62 #include <sys/mbuf.h>
63 #include <sys/module.h>
64 #include <sys/mutex.h>
65 #include <sys/rman.h>
66 #include <sys/socket.h>
67 #include <sys/sockio.h>
68 #include <sys/sysctl.h>
69 
70 #include <machine/bus.h>
71 
72 #include <net/bpf.h>
73 #include <net/if.h>
74 #include <net/ethernet.h>
75 #include <net/if_dl.h>
76 #include <net/if_media.h>
77 #include <net/if_types.h>
78 #include <net/if_var.h>
79 #include <net/if_vlan_var.h>
80 
81 #include <dev/fdt/fdt_common.h>
82 #include <dev/ffec/if_ffecreg.h>
83 #include <dev/ofw/ofw_bus.h>
84 #include <dev/ofw/ofw_bus_subr.h>
85 #include <dev/mii/mii.h>
86 #include <dev/mii/miivar.h>
87 #include <dev/mii/mii_fdt.h>
88 #include "miibus_if.h"
89 
90 /*
91  * There are small differences in the hardware on various SoCs.  Not every SoC
92  * we support has its own FECTYPE; most work as GENERIC and only the ones that
93  * need different handling get their own entry.  In addition to the types in
94  * this list, there are some flags below that can be ORed into the upper bits.
95  */
96 enum {
97 	FECTYPE_NONE,
98 	FECTYPE_GENERIC,
99 	FECTYPE_IMX53,
100 	FECTYPE_IMX6,	/* imx6 and imx7 */
101 	FECTYPE_MVF,
102 };
103 
104 /*
105  * Flags that describe general differences between the FEC hardware in various
106  * SoCs.  These are ORed into the FECTYPE enum values in the ofw_compat_data, so
107  * the low 8 bits are reserved for the type enum.  In the softc, the type and
108  * flags are put into separate members, so that you don't need to mask the flags
109  * out of the type to compare it.
110  */
111 #define	FECTYPE_MASK		0x000000ff
112 #define	FECFLAG_GBE		(1 <<  8)
113 #define	FECFLAG_AVB		(1 <<  9)
114 #define	FECFLAG_RACC		(1 << 10)
115 
116 /*
117  * Table of supported FDT compat strings and their associated FECTYPE values.
118  */
119 static struct ofw_compat_data compat_data[] = {
120 	{"fsl,imx51-fec",	FECTYPE_GENERIC},
121 	{"fsl,imx53-fec",	FECTYPE_IMX53},
122 	{"fsl,imx6q-fec",	FECTYPE_IMX6 | FECFLAG_RACC | FECFLAG_GBE },
123 	{"fsl,imx6ul-fec",	FECTYPE_IMX6 | FECFLAG_RACC },
124 	{"fsl,imx6sx-fec",	FECTYPE_IMX6 | FECFLAG_RACC | FECFLAG_GBE |
125 				FECFLAG_AVB },
126 	{"fsl,imx7d-fec",	FECTYPE_IMX6 | FECFLAG_RACC | FECFLAG_GBE |
127 				FECFLAG_AVB },
128 	{"fsl,mvf600-fec",	FECTYPE_MVF  | FECFLAG_RACC },
129 	{"fsl,mvf-fec",		FECTYPE_MVF},
130 	{NULL,		 	FECTYPE_NONE},
131 };
132 
133 /*
134  * Driver data and defines.
135  */
136 #define	RX_DESC_COUNT	64
137 #define	RX_DESC_SIZE	(sizeof(struct ffec_hwdesc) * RX_DESC_COUNT)
138 #define	TX_DESC_COUNT	64
139 #define	TX_DESC_SIZE	(sizeof(struct ffec_hwdesc) * TX_DESC_COUNT)
140 
141 #define	WATCHDOG_TIMEOUT_SECS	5
142 
143 #define	MAX_IRQ_COUNT 3
144 
145 struct ffec_bufmap {
146 	struct mbuf	*mbuf;
147 	bus_dmamap_t	map;
148 };
149 
150 struct ffec_softc {
151 	device_t		dev;
152 	device_t		miibus;
153 	struct mii_data *	mii_softc;
154 	if_t			ifp;
155 	int			if_flags;
156 	struct mtx		mtx;
157 	struct resource		*irq_res[MAX_IRQ_COUNT];
158 	struct resource		*mem_res;
159 	void *			intr_cookie[MAX_IRQ_COUNT];
160 	struct callout		ffec_callout;
161 	mii_contype_t		phy_conn_type;
162 	uint32_t		fecflags;
163 	uint8_t			fectype;
164 	boolean_t		link_is_up;
165 	boolean_t		is_attached;
166 	boolean_t		is_detaching;
167 	int			tx_watchdog_count;
168 	int			rxbuf_align;
169 	int			txbuf_align;
170 
171 	bus_dma_tag_t		rxdesc_tag;
172 	bus_dmamap_t		rxdesc_map;
173 	struct ffec_hwdesc	*rxdesc_ring;
174 	bus_addr_t		rxdesc_ring_paddr;
175 	bus_dma_tag_t		rxbuf_tag;
176 	struct ffec_bufmap	rxbuf_map[RX_DESC_COUNT];
177 	uint32_t		rx_idx;
178 
179 	bus_dma_tag_t		txdesc_tag;
180 	bus_dmamap_t		txdesc_map;
181 	struct ffec_hwdesc	*txdesc_ring;
182 	bus_addr_t		txdesc_ring_paddr;
183 	bus_dma_tag_t		txbuf_tag;
184 	struct ffec_bufmap	txbuf_map[TX_DESC_COUNT];
185 	uint32_t		tx_idx_head;
186 	uint32_t		tx_idx_tail;
187 	int			txcount;
188 };
189 
190 static struct resource_spec irq_res_spec[MAX_IRQ_COUNT + 1] = {
191 	{ SYS_RES_IRQ,		0,	RF_ACTIVE },
192 	{ SYS_RES_IRQ,		1,	RF_ACTIVE | RF_OPTIONAL },
193 	{ SYS_RES_IRQ,		2,	RF_ACTIVE | RF_OPTIONAL },
194 	RESOURCE_SPEC_END
195 };
196 
197 #define	FFEC_LOCK(sc)			mtx_lock(&(sc)->mtx)
198 #define	FFEC_UNLOCK(sc)			mtx_unlock(&(sc)->mtx)
199 #define	FFEC_LOCK_INIT(sc)		mtx_init(&(sc)->mtx, \
200 	    device_get_nameunit((sc)->dev), MTX_NETWORK_LOCK, MTX_DEF)
201 #define	FFEC_LOCK_DESTROY(sc)		mtx_destroy(&(sc)->mtx);
202 #define	FFEC_ASSERT_LOCKED(sc)		mtx_assert(&(sc)->mtx, MA_OWNED);
203 #define	FFEC_ASSERT_UNLOCKED(sc)	mtx_assert(&(sc)->mtx, MA_NOTOWNED);
204 
205 static void ffec_init_locked(struct ffec_softc *sc);
206 static void ffec_stop_locked(struct ffec_softc *sc);
207 static void ffec_txstart_locked(struct ffec_softc *sc);
208 static void ffec_txfinish_locked(struct ffec_softc *sc);
209 
210 static inline uint16_t
211 RD2(struct ffec_softc *sc, bus_size_t off)
212 {
213 
214 	return (bus_read_2(sc->mem_res, off));
215 }
216 
217 static inline void
218 WR2(struct ffec_softc *sc, bus_size_t off, uint16_t val)
219 {
220 
221 	bus_write_2(sc->mem_res, off, val);
222 }
223 
224 static inline uint32_t
225 RD4(struct ffec_softc *sc, bus_size_t off)
226 {
227 
228 	return (bus_read_4(sc->mem_res, off));
229 }
230 
231 static inline void
232 WR4(struct ffec_softc *sc, bus_size_t off, uint32_t val)
233 {
234 
235 	bus_write_4(sc->mem_res, off, val);
236 }
237 
238 static inline uint32_t
239 next_rxidx(struct ffec_softc *sc, uint32_t curidx)
240 {
241 
242 	return ((curidx == RX_DESC_COUNT - 1) ? 0 : curidx + 1);
243 }
244 
245 static inline uint32_t
246 next_txidx(struct ffec_softc *sc, uint32_t curidx)
247 {
248 
249 	return ((curidx == TX_DESC_COUNT - 1) ? 0 : curidx + 1);
250 }
251 
252 static void
253 ffec_get1paddr(void *arg, bus_dma_segment_t *segs, int nsegs, int error)
254 {
255 
256 	if (error != 0)
257 		return;
258 	*(bus_addr_t *)arg = segs[0].ds_addr;
259 }
260 
261 static void
262 ffec_miigasket_setup(struct ffec_softc *sc)
263 {
264 	uint32_t ifmode;
265 
266 	/*
267 	 * We only need the gasket for MII and RMII connections on certain SoCs.
268 	 */
269 
270 	switch (sc->fectype)
271 	{
272 	case FECTYPE_IMX53:
273 		break;
274 	default:
275 		return;
276 	}
277 
278 	switch (sc->phy_conn_type)
279 	{
280 	case MII_CONTYPE_MII:
281 		ifmode = 0;
282 		break;
283 	case MII_CONTYPE_RMII:
284 		ifmode = FEC_MIIGSK_CFGR_IF_MODE_RMII;
285 		break;
286 	default:
287 		return;
288 	}
289 
290 	/*
291 	 * Disable the gasket, configure for either MII or RMII, then enable.
292 	 */
293 
294 	WR2(sc, FEC_MIIGSK_ENR, 0);
295 	while (RD2(sc, FEC_MIIGSK_ENR) & FEC_MIIGSK_ENR_READY)
296 		continue;
297 
298 	WR2(sc, FEC_MIIGSK_CFGR, ifmode);
299 
300 	WR2(sc, FEC_MIIGSK_ENR, FEC_MIIGSK_ENR_EN);
301 	while (!(RD2(sc, FEC_MIIGSK_ENR) & FEC_MIIGSK_ENR_READY))
302 		continue;
303 }
304 
305 static boolean_t
306 ffec_miibus_iowait(struct ffec_softc *sc)
307 {
308 	uint32_t timeout;
309 
310 	for (timeout = 10000; timeout != 0; --timeout)
311 		if (RD4(sc, FEC_IER_REG) & FEC_IER_MII)
312 			return (true);
313 
314 	return (false);
315 }
316 
317 static int
318 ffec_miibus_readreg(device_t dev, int phy, int reg)
319 {
320 	struct ffec_softc *sc;
321 	int val;
322 
323 	sc = device_get_softc(dev);
324 
325 	WR4(sc, FEC_IER_REG, FEC_IER_MII);
326 
327 	WR4(sc, FEC_MMFR_REG, FEC_MMFR_OP_READ |
328 	    FEC_MMFR_ST_VALUE | FEC_MMFR_TA_VALUE |
329 	    ((phy << FEC_MMFR_PA_SHIFT) & FEC_MMFR_PA_MASK) |
330 	    ((reg << FEC_MMFR_RA_SHIFT) & FEC_MMFR_RA_MASK));
331 
332 	if (!ffec_miibus_iowait(sc)) {
333 		device_printf(dev, "timeout waiting for mii read\n");
334 		return (-1); /* All-ones is a symptom of bad mdio. */
335 	}
336 
337 	val = RD4(sc, FEC_MMFR_REG) & FEC_MMFR_DATA_MASK;
338 
339 	return (val);
340 }
341 
342 static int
343 ffec_miibus_writereg(device_t dev, int phy, int reg, int val)
344 {
345 	struct ffec_softc *sc;
346 
347 	sc = device_get_softc(dev);
348 
349 	WR4(sc, FEC_IER_REG, FEC_IER_MII);
350 
351 	WR4(sc, FEC_MMFR_REG, FEC_MMFR_OP_WRITE |
352 	    FEC_MMFR_ST_VALUE | FEC_MMFR_TA_VALUE |
353 	    ((phy << FEC_MMFR_PA_SHIFT) & FEC_MMFR_PA_MASK) |
354 	    ((reg << FEC_MMFR_RA_SHIFT) & FEC_MMFR_RA_MASK) |
355 	    (val & FEC_MMFR_DATA_MASK));
356 
357 	if (!ffec_miibus_iowait(sc)) {
358 		device_printf(dev, "timeout waiting for mii write\n");
359 		return (-1);
360 	}
361 
362 	return (0);
363 }
364 
365 static void
366 ffec_miibus_statchg(device_t dev)
367 {
368 	struct ffec_softc *sc;
369 	struct mii_data *mii;
370 	uint32_t ecr, rcr, tcr;
371 
372 	/*
373 	 * Called by the MII bus driver when the PHY establishes link to set the
374 	 * MAC interface registers.
375 	 */
376 
377 	sc = device_get_softc(dev);
378 
379 	FFEC_ASSERT_LOCKED(sc);
380 
381 	mii = sc->mii_softc;
382 
383 	if (mii->mii_media_status & IFM_ACTIVE)
384 		sc->link_is_up = true;
385 	else
386 		sc->link_is_up = false;
387 
388 	ecr = RD4(sc, FEC_ECR_REG) & ~FEC_ECR_SPEED;
389 	rcr = RD4(sc, FEC_RCR_REG) & ~(FEC_RCR_RMII_10T | FEC_RCR_RMII_MODE |
390 	    FEC_RCR_RGMII_EN | FEC_RCR_DRT | FEC_RCR_FCE);
391 	tcr = RD4(sc, FEC_TCR_REG) & ~FEC_TCR_FDEN;
392 
393 	rcr |= FEC_RCR_MII_MODE; /* Must always be on even for R[G]MII. */
394 	switch (sc->phy_conn_type) {
395 	case MII_CONTYPE_RMII:
396 		rcr |= FEC_RCR_RMII_MODE;
397 		break;
398 	case MII_CONTYPE_RGMII:
399 	case MII_CONTYPE_RGMII_ID:
400 	case MII_CONTYPE_RGMII_RXID:
401 	case MII_CONTYPE_RGMII_TXID:
402 		rcr |= FEC_RCR_RGMII_EN;
403 		break;
404 	default:
405 		break;
406 	}
407 
408 	switch (IFM_SUBTYPE(mii->mii_media_active)) {
409 	case IFM_1000_T:
410 	case IFM_1000_SX:
411 		ecr |= FEC_ECR_SPEED;
412 		break;
413 	case IFM_100_TX:
414 		/* Not-FEC_ECR_SPEED + not-FEC_RCR_RMII_10T means 100TX */
415 		break;
416 	case IFM_10_T:
417 		rcr |= FEC_RCR_RMII_10T;
418 		break;
419 	case IFM_NONE:
420 		sc->link_is_up = false;
421 		return;
422 	default:
423 		sc->link_is_up = false;
424 		device_printf(dev, "Unsupported media %u\n",
425 		    IFM_SUBTYPE(mii->mii_media_active));
426 		return;
427 	}
428 
429 	if ((IFM_OPTIONS(mii->mii_media_active) & IFM_FDX) != 0)
430 		tcr |= FEC_TCR_FDEN;
431 	else
432 		rcr |= FEC_RCR_DRT;
433 
434 	if ((IFM_OPTIONS(mii->mii_media_active) & IFM_FLOW) != 0)
435 		rcr |= FEC_RCR_FCE;
436 
437 	WR4(sc, FEC_RCR_REG, rcr);
438 	WR4(sc, FEC_TCR_REG, tcr);
439 	WR4(sc, FEC_ECR_REG, ecr);
440 }
441 
442 static void
443 ffec_media_status(if_t  ifp, struct ifmediareq *ifmr)
444 {
445 	struct ffec_softc *sc;
446 	struct mii_data *mii;
447 
448 
449 	sc = if_getsoftc(ifp);
450 	mii = sc->mii_softc;
451 	FFEC_LOCK(sc);
452 	mii_pollstat(mii);
453 	ifmr->ifm_active = mii->mii_media_active;
454 	ifmr->ifm_status = mii->mii_media_status;
455 	FFEC_UNLOCK(sc);
456 }
457 
458 static int
459 ffec_media_change_locked(struct ffec_softc *sc)
460 {
461 
462 	return (mii_mediachg(sc->mii_softc));
463 }
464 
465 static int
466 ffec_media_change(if_t  ifp)
467 {
468 	struct ffec_softc *sc;
469 	int error;
470 
471 	sc = if_getsoftc(ifp);
472 
473 	FFEC_LOCK(sc);
474 	error = ffec_media_change_locked(sc);
475 	FFEC_UNLOCK(sc);
476 	return (error);
477 }
478 
479 static void ffec_clear_stats(struct ffec_softc *sc)
480 {
481 	uint32_t mibc;
482 
483 	mibc = RD4(sc, FEC_MIBC_REG);
484 
485 	/*
486 	 * On newer hardware the statistic regs are cleared by toggling a bit in
487 	 * the mib control register.  On older hardware the clear procedure is
488 	 * to disable statistics collection, zero the regs, then re-enable.
489 	 */
490 	if (sc->fectype == FECTYPE_IMX6 || sc->fectype == FECTYPE_MVF) {
491 		WR4(sc, FEC_MIBC_REG, mibc | FEC_MIBC_CLEAR);
492 		WR4(sc, FEC_MIBC_REG, mibc & ~FEC_MIBC_CLEAR);
493 	} else {
494 		WR4(sc, FEC_MIBC_REG, mibc | FEC_MIBC_DIS);
495 
496 		WR4(sc, FEC_IEEE_R_DROP, 0);
497 		WR4(sc, FEC_IEEE_R_MACERR, 0);
498 		WR4(sc, FEC_RMON_R_CRC_ALIGN, 0);
499 		WR4(sc, FEC_RMON_R_FRAG, 0);
500 		WR4(sc, FEC_RMON_R_JAB, 0);
501 		WR4(sc, FEC_RMON_R_MC_PKT, 0);
502 		WR4(sc, FEC_RMON_R_OVERSIZE, 0);
503 		WR4(sc, FEC_RMON_R_PACKETS, 0);
504 		WR4(sc, FEC_RMON_R_UNDERSIZE, 0);
505 		WR4(sc, FEC_RMON_T_COL, 0);
506 		WR4(sc, FEC_RMON_T_CRC_ALIGN, 0);
507 		WR4(sc, FEC_RMON_T_FRAG, 0);
508 		WR4(sc, FEC_RMON_T_JAB, 0);
509 		WR4(sc, FEC_RMON_T_MC_PKT, 0);
510 		WR4(sc, FEC_RMON_T_OVERSIZE , 0);
511 		WR4(sc, FEC_RMON_T_PACKETS, 0);
512 		WR4(sc, FEC_RMON_T_UNDERSIZE, 0);
513 
514 		WR4(sc, FEC_MIBC_REG, mibc);
515 	}
516 }
517 
518 static void
519 ffec_harvest_stats(struct ffec_softc *sc)
520 {
521 	if_t ifp;
522 
523 	ifp = sc->ifp;
524 
525 	/*
526 	 * - FEC_IEEE_R_DROP is "dropped due to invalid start frame delimiter"
527 	 *   so it's really just another type of input error.
528 	 * - FEC_IEEE_R_MACERR is "no receive fifo space"; count as input drops.
529 	 */
530 	if_inc_counter(ifp, IFCOUNTER_IPACKETS, RD4(sc, FEC_RMON_R_PACKETS));
531 	if_inc_counter(ifp, IFCOUNTER_IMCASTS, RD4(sc, FEC_RMON_R_MC_PKT));
532 	if_inc_counter(ifp, IFCOUNTER_IERRORS,
533 	    RD4(sc, FEC_RMON_R_CRC_ALIGN) + RD4(sc, FEC_RMON_R_UNDERSIZE) +
534 	    RD4(sc, FEC_RMON_R_OVERSIZE) + RD4(sc, FEC_RMON_R_FRAG) +
535 	    RD4(sc, FEC_RMON_R_JAB) + RD4(sc, FEC_IEEE_R_DROP));
536 
537 	if_inc_counter(ifp, IFCOUNTER_IQDROPS, RD4(sc, FEC_IEEE_R_MACERR));
538 
539 	if_inc_counter(ifp, IFCOUNTER_OPACKETS, RD4(sc, FEC_RMON_T_PACKETS));
540 	if_inc_counter(ifp, IFCOUNTER_OMCASTS, RD4(sc, FEC_RMON_T_MC_PKT));
541 	if_inc_counter(ifp, IFCOUNTER_OERRORS,
542 	    RD4(sc, FEC_RMON_T_CRC_ALIGN) + RD4(sc, FEC_RMON_T_UNDERSIZE) +
543 	    RD4(sc, FEC_RMON_T_OVERSIZE) + RD4(sc, FEC_RMON_T_FRAG) +
544 	    RD4(sc, FEC_RMON_T_JAB));
545 
546 	if_inc_counter(ifp, IFCOUNTER_COLLISIONS, RD4(sc, FEC_RMON_T_COL));
547 
548 	ffec_clear_stats(sc);
549 }
550 
551 static void
552 ffec_tick(void *arg)
553 {
554 	struct ffec_softc *sc;
555 	if_t ifp;
556 	int link_was_up;
557 
558 	sc = arg;
559 
560 	FFEC_ASSERT_LOCKED(sc);
561 
562 	ifp = sc->ifp;
563 
564 	if (!(if_getdrvflags(ifp) & IFF_DRV_RUNNING))
565 	    return;
566 
567 	/*
568 	 * Typical tx watchdog.  If this fires it indicates that we enqueued
569 	 * packets for output and never got a txdone interrupt for them.  Maybe
570 	 * it's a missed interrupt somehow, just pretend we got one.
571 	 */
572 	if (sc->tx_watchdog_count > 0) {
573 		if (--sc->tx_watchdog_count == 0) {
574 			ffec_txfinish_locked(sc);
575 		}
576 	}
577 
578 	/* Gather stats from hardware counters. */
579 	ffec_harvest_stats(sc);
580 
581 	/* Check the media status. */
582 	link_was_up = sc->link_is_up;
583 	mii_tick(sc->mii_softc);
584 	if (sc->link_is_up && !link_was_up)
585 		ffec_txstart_locked(sc);
586 
587 	/* Schedule another check one second from now. */
588 	callout_reset(&sc->ffec_callout, hz, ffec_tick, sc);
589 }
590 
591 inline static uint32_t
592 ffec_setup_txdesc(struct ffec_softc *sc, int idx, bus_addr_t paddr,
593     uint32_t len)
594 {
595 	uint32_t nidx;
596 	uint32_t flags;
597 
598 	nidx = next_txidx(sc, idx);
599 
600 	/* Addr/len 0 means we're clearing the descriptor after xmit done. */
601 	if (paddr == 0 || len == 0) {
602 		flags = 0;
603 		--sc->txcount;
604 	} else {
605 		flags = FEC_TXDESC_READY | FEC_TXDESC_L | FEC_TXDESC_TC;
606 		++sc->txcount;
607 	}
608 	if (nidx == 0)
609 		flags |= FEC_TXDESC_WRAP;
610 
611 	/*
612 	 * The hardware requires 32-bit physical addresses.  We set up the dma
613 	 * tag to indicate that, so the cast to uint32_t should never lose
614 	 * significant bits.
615 	 */
616 	sc->txdesc_ring[idx].buf_paddr = (uint32_t)paddr;
617 	sc->txdesc_ring[idx].flags_len = flags | len; /* Must be set last! */
618 
619 	return (nidx);
620 }
621 
622 static int
623 ffec_setup_txbuf(struct ffec_softc *sc, int idx, struct mbuf **mp)
624 {
625 	struct mbuf * m;
626 	int error, nsegs;
627 	struct bus_dma_segment seg;
628 
629 	if ((m = m_defrag(*mp, M_NOWAIT)) == NULL)
630 		return (ENOMEM);
631 	*mp = m;
632 
633 	error = bus_dmamap_load_mbuf_sg(sc->txbuf_tag, sc->txbuf_map[idx].map,
634 	    m, &seg, &nsegs, 0);
635 	if (error != 0) {
636 		return (ENOMEM);
637 	}
638 	bus_dmamap_sync(sc->txbuf_tag, sc->txbuf_map[idx].map,
639 	    BUS_DMASYNC_PREWRITE);
640 
641 	sc->txbuf_map[idx].mbuf = m;
642 	ffec_setup_txdesc(sc, idx, seg.ds_addr, seg.ds_len);
643 
644 	return (0);
645 
646 }
647 
648 static void
649 ffec_txstart_locked(struct ffec_softc *sc)
650 {
651 	if_t ifp;
652 	struct mbuf *m;
653 	int enqueued;
654 
655 	FFEC_ASSERT_LOCKED(sc);
656 
657 	if (!sc->link_is_up)
658 		return;
659 
660 	ifp = sc->ifp;
661 
662 	if (if_getdrvflags(ifp) & IFF_DRV_OACTIVE)
663 		return;
664 
665 	enqueued = 0;
666 
667 	for (;;) {
668 		if (sc->txcount == (TX_DESC_COUNT-1)) {
669 			if_setdrvflagbits(ifp, IFF_DRV_OACTIVE, 0);
670 			break;
671 		}
672 		m = if_dequeue(ifp);
673 		if (m == NULL)
674 			break;
675 		if (ffec_setup_txbuf(sc, sc->tx_idx_head, &m) != 0) {
676 			if_sendq_prepend(ifp, m);
677 			break;
678 		}
679 		BPF_MTAP(ifp, m);
680 		sc->tx_idx_head = next_txidx(sc, sc->tx_idx_head);
681 		++enqueued;
682 	}
683 
684 	if (enqueued != 0) {
685 		bus_dmamap_sync(sc->txdesc_tag, sc->txdesc_map, BUS_DMASYNC_PREWRITE);
686 		WR4(sc, FEC_TDAR_REG, FEC_TDAR_TDAR);
687 		bus_dmamap_sync(sc->txdesc_tag, sc->txdesc_map, BUS_DMASYNC_POSTWRITE);
688 		sc->tx_watchdog_count = WATCHDOG_TIMEOUT_SECS;
689 	}
690 }
691 
692 static void
693 ffec_txstart(if_t ifp)
694 {
695 	struct ffec_softc *sc = if_getsoftc(ifp);
696 
697 	FFEC_LOCK(sc);
698 	ffec_txstart_locked(sc);
699 	FFEC_UNLOCK(sc);
700 }
701 
702 static void
703 ffec_txfinish_locked(struct ffec_softc *sc)
704 {
705 	if_t ifp;
706 	struct ffec_hwdesc *desc;
707 	struct ffec_bufmap *bmap;
708 	boolean_t retired_buffer;
709 
710 	FFEC_ASSERT_LOCKED(sc);
711 
712 	/* XXX Can't set PRE|POST right now, but we need both. */
713 	bus_dmamap_sync(sc->txdesc_tag, sc->txdesc_map, BUS_DMASYNC_PREREAD);
714 	bus_dmamap_sync(sc->txdesc_tag, sc->txdesc_map, BUS_DMASYNC_POSTREAD);
715 	ifp = sc->ifp;
716 	retired_buffer = false;
717 	while (sc->tx_idx_tail != sc->tx_idx_head) {
718 		desc = &sc->txdesc_ring[sc->tx_idx_tail];
719 		if (desc->flags_len & FEC_TXDESC_READY)
720 			break;
721 		retired_buffer = true;
722 		bmap = &sc->txbuf_map[sc->tx_idx_tail];
723 		bus_dmamap_sync(sc->txbuf_tag, bmap->map,
724 		    BUS_DMASYNC_POSTWRITE);
725 		bus_dmamap_unload(sc->txbuf_tag, bmap->map);
726 		m_freem(bmap->mbuf);
727 		bmap->mbuf = NULL;
728 		ffec_setup_txdesc(sc, sc->tx_idx_tail, 0, 0);
729 		sc->tx_idx_tail = next_txidx(sc, sc->tx_idx_tail);
730 	}
731 
732 	/*
733 	 * If we retired any buffers, there will be open tx slots available in
734 	 * the descriptor ring, go try to start some new output.
735 	 */
736 	if (retired_buffer) {
737 		if_setdrvflagbits(ifp, 0, IFF_DRV_OACTIVE);
738 		ffec_txstart_locked(sc);
739 	}
740 
741 	/* If there are no buffers outstanding, muzzle the watchdog. */
742 	if (sc->tx_idx_tail == sc->tx_idx_head) {
743 		sc->tx_watchdog_count = 0;
744 	}
745 }
746 
747 inline static uint32_t
748 ffec_setup_rxdesc(struct ffec_softc *sc, int idx, bus_addr_t paddr)
749 {
750 	uint32_t nidx;
751 
752 	/*
753 	 * The hardware requires 32-bit physical addresses.  We set up the dma
754 	 * tag to indicate that, so the cast to uint32_t should never lose
755 	 * significant bits.
756 	 */
757 	nidx = next_rxidx(sc, idx);
758 	sc->rxdesc_ring[idx].buf_paddr = (uint32_t)paddr;
759 	sc->rxdesc_ring[idx].flags_len = FEC_RXDESC_EMPTY |
760 		((nidx == 0) ? FEC_RXDESC_WRAP : 0);
761 
762 	return (nidx);
763 }
764 
765 static int
766 ffec_setup_rxbuf(struct ffec_softc *sc, int idx, struct mbuf * m)
767 {
768 	int error, nsegs;
769 	struct bus_dma_segment seg;
770 
771 	if (!(sc->fecflags & FECFLAG_RACC)) {
772 		/*
773 		 * The RACC[SHIFT16] feature is not available.  So, we need to
774 		 * leave at least ETHER_ALIGN bytes free at the beginning of the
775 		 * buffer to allow the data to be re-aligned after receiving it
776 		 * (by copying it backwards ETHER_ALIGN bytes in the same
777 		 * buffer).  We also have to ensure that the beginning of the
778 		 * buffer is aligned to the hardware's requirements.
779 		 */
780 		m_adj(m, roundup(ETHER_ALIGN, sc->rxbuf_align));
781 	}
782 
783 	error = bus_dmamap_load_mbuf_sg(sc->rxbuf_tag, sc->rxbuf_map[idx].map,
784 	    m, &seg, &nsegs, 0);
785 	if (error != 0) {
786 		return (error);
787 	}
788 
789 	bus_dmamap_sync(sc->rxbuf_tag, sc->rxbuf_map[idx].map,
790 	    BUS_DMASYNC_PREREAD);
791 
792 	sc->rxbuf_map[idx].mbuf = m;
793 	ffec_setup_rxdesc(sc, idx, seg.ds_addr);
794 
795 	return (0);
796 }
797 
798 static struct mbuf *
799 ffec_alloc_mbufcl(struct ffec_softc *sc)
800 {
801 	struct mbuf *m;
802 
803 	m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
804 	if (m != NULL)
805 		m->m_pkthdr.len = m->m_len = m->m_ext.ext_size;
806 
807 	return (m);
808 }
809 
810 static void
811 ffec_rxfinish_onebuf(struct ffec_softc *sc, int len)
812 {
813 	struct mbuf *m, *newmbuf;
814 	struct ffec_bufmap *bmap;
815 	uint8_t *dst, *src;
816 	int error;
817 
818 	/*
819 	 *  First try to get a new mbuf to plug into this slot in the rx ring.
820 	 *  If that fails, drop the current packet and recycle the current
821 	 *  mbuf, which is still mapped and loaded.
822 	 */
823 	if ((newmbuf = ffec_alloc_mbufcl(sc)) == NULL) {
824 		if_inc_counter(sc->ifp, IFCOUNTER_IQDROPS, 1);
825 		ffec_setup_rxdesc(sc, sc->rx_idx,
826 		    sc->rxdesc_ring[sc->rx_idx].buf_paddr);
827 		return;
828 	}
829 
830 	FFEC_UNLOCK(sc);
831 
832 	bmap = &sc->rxbuf_map[sc->rx_idx];
833 	len -= ETHER_CRC_LEN;
834 	bus_dmamap_sync(sc->rxbuf_tag, bmap->map, BUS_DMASYNC_POSTREAD);
835 	bus_dmamap_unload(sc->rxbuf_tag, bmap->map);
836 	m = bmap->mbuf;
837 	bmap->mbuf = NULL;
838 	m->m_len = len;
839 	m->m_pkthdr.len = len;
840 	m->m_pkthdr.rcvif = sc->ifp;
841 
842 	/*
843 	 * Align the protocol headers in the receive buffer on a 32-bit
844 	 * boundary.  Newer hardware does the alignment for us.  On hardware
845 	 * that doesn't support this feature, we have to copy-align the data.
846 	 *
847 	 *  XXX for older hardware, could we speed this up by copying just the
848 	 *  protocol headers into their own small mbuf then chaining the cluster
849 	 *  to it? That way we'd only need to copy like 64 bytes or whatever the
850 	 *  biggest header is, instead of the whole 1530ish-byte frame.
851 	 */
852 	if (sc->fecflags & FECFLAG_RACC) {
853 		m->m_data = mtod(m, uint8_t *) + 2;
854 	} else {
855 		src = mtod(m, uint8_t*);
856 		dst = src - ETHER_ALIGN;
857 		bcopy(src, dst, len);
858 		m->m_data = dst;
859 	}
860 	if_input(sc->ifp, m);
861 
862 	FFEC_LOCK(sc);
863 
864 	if ((error = ffec_setup_rxbuf(sc, sc->rx_idx, newmbuf)) != 0) {
865 		device_printf(sc->dev, "ffec_setup_rxbuf error %d\n", error);
866 		/* XXX Now what?  We've got a hole in the rx ring. */
867 	}
868 
869 }
870 
871 static void
872 ffec_rxfinish_locked(struct ffec_softc *sc)
873 {
874 	struct ffec_hwdesc *desc;
875 	int len;
876 	boolean_t produced_empty_buffer;
877 
878 	FFEC_ASSERT_LOCKED(sc);
879 
880 	/* XXX Can't set PRE|POST right now, but we need both. */
881 	bus_dmamap_sync(sc->rxdesc_tag, sc->rxdesc_map, BUS_DMASYNC_PREREAD);
882 	bus_dmamap_sync(sc->rxdesc_tag, sc->rxdesc_map, BUS_DMASYNC_POSTREAD);
883 	produced_empty_buffer = false;
884 	for (;;) {
885 		desc = &sc->rxdesc_ring[sc->rx_idx];
886 		if (desc->flags_len & FEC_RXDESC_EMPTY)
887 			break;
888 		produced_empty_buffer = true;
889 		len = (desc->flags_len & FEC_RXDESC_LEN_MASK);
890 		if (len < 64) {
891 			/*
892 			 * Just recycle the descriptor and continue.           .
893 			 */
894 			ffec_setup_rxdesc(sc, sc->rx_idx,
895 			    sc->rxdesc_ring[sc->rx_idx].buf_paddr);
896 		} else if ((desc->flags_len & FEC_RXDESC_L) == 0) {
897 			/*
898 			 * The entire frame is not in this buffer.  Impossible.
899 			 * Recycle the descriptor and continue.
900 			 *
901 			 * XXX what's the right way to handle this? Probably we
902 			 * should stop/init the hardware because this should
903 			 * just really never happen when we have buffers bigger
904 			 * than the maximum frame size.
905 			 */
906 			device_printf(sc->dev,
907 			    "fec_rxfinish: received frame without LAST bit set");
908 			ffec_setup_rxdesc(sc, sc->rx_idx,
909 			    sc->rxdesc_ring[sc->rx_idx].buf_paddr);
910 		} else if (desc->flags_len & FEC_RXDESC_ERROR_BITS) {
911 			/*
912 			 *  Something went wrong with receiving the frame, we
913 			 *  don't care what (the hardware has counted the error
914 			 *  in the stats registers already), we just reuse the
915 			 *  same mbuf, which is still dma-mapped, by resetting
916 			 *  the rx descriptor.
917 			 */
918 			ffec_setup_rxdesc(sc, sc->rx_idx,
919 			    sc->rxdesc_ring[sc->rx_idx].buf_paddr);
920 		} else {
921 			/*
922 			 *  Normal case: a good frame all in one buffer.
923 			 */
924 			ffec_rxfinish_onebuf(sc, len);
925 		}
926 		sc->rx_idx = next_rxidx(sc, sc->rx_idx);
927 	}
928 
929 	if (produced_empty_buffer) {
930 		bus_dmamap_sync(sc->rxdesc_tag, sc->rxdesc_map, BUS_DMASYNC_PREWRITE);
931 		WR4(sc, FEC_RDAR_REG, FEC_RDAR_RDAR);
932 		bus_dmamap_sync(sc->rxdesc_tag, sc->rxdesc_map, BUS_DMASYNC_POSTWRITE);
933 	}
934 }
935 
936 static void
937 ffec_get_hwaddr(struct ffec_softc *sc, uint8_t *hwaddr)
938 {
939 	uint32_t palr, paur, rnd;
940 
941 	/*
942 	 * Try to recover a MAC address from the running hardware. If there's
943 	 * something non-zero there, assume the bootloader did the right thing
944 	 * and just use it.
945 	 *
946 	 * Otherwise, set the address to a convenient locally assigned address,
947 	 * 'bsd' + random 24 low-order bits.  'b' is 0x62, which has the locally
948 	 * assigned bit set, and the broadcast/multicast bit clear.
949 	 */
950 	palr = RD4(sc, FEC_PALR_REG);
951 	paur = RD4(sc, FEC_PAUR_REG) & FEC_PAUR_PADDR2_MASK;
952 	if ((palr | paur) != 0) {
953 		hwaddr[0] = palr >> 24;
954 		hwaddr[1] = palr >> 16;
955 		hwaddr[2] = palr >>  8;
956 		hwaddr[3] = palr >>  0;
957 		hwaddr[4] = paur >> 24;
958 		hwaddr[5] = paur >> 16;
959 	} else {
960 		rnd = arc4random() & 0x00ffffff;
961 		hwaddr[0] = 'b';
962 		hwaddr[1] = 's';
963 		hwaddr[2] = 'd';
964 		hwaddr[3] = rnd >> 16;
965 		hwaddr[4] = rnd >>  8;
966 		hwaddr[5] = rnd >>  0;
967 	}
968 
969 	if (bootverbose) {
970 		device_printf(sc->dev,
971 		    "MAC address %02x:%02x:%02x:%02x:%02x:%02x\n",
972 		    hwaddr[0], hwaddr[1], hwaddr[2],
973 		    hwaddr[3], hwaddr[4], hwaddr[5]);
974 	}
975 }
976 
977 static u_int
978 ffec_hash_maddr(void *arg, struct sockaddr_dl *sdl, u_int cnt)
979 {
980 	uint64_t *ghash = arg;
981 	uint32_t crc;
982 
983 	/* 6 bits from MSB in LE CRC32 are used for hash. */
984 	crc = ether_crc32_le(LLADDR(sdl), ETHER_ADDR_LEN);
985 	*ghash |= 1LLU << (((uint8_t *)&crc)[3] >> 2);
986 
987 	return (1);
988 }
989 
990 static void
991 ffec_setup_rxfilter(struct ffec_softc *sc)
992 {
993 	if_t ifp;
994 	uint8_t *eaddr;
995 	uint64_t ghash, ihash;
996 
997 	FFEC_ASSERT_LOCKED(sc);
998 
999 	ifp = sc->ifp;
1000 
1001 	/*
1002 	 * Set the multicast (group) filter hash.
1003 	 */
1004 	if ((if_getflags(ifp) & IFF_ALLMULTI))
1005 		ghash = 0xffffffffffffffffLLU;
1006 	else {
1007 		ghash = 0;
1008 		if_foreach_llmaddr(ifp, ffec_hash_maddr, &ghash);
1009 	}
1010 	WR4(sc, FEC_GAUR_REG, (uint32_t)(ghash >> 32));
1011 	WR4(sc, FEC_GALR_REG, (uint32_t)ghash);
1012 
1013 	/*
1014 	 * Set the individual address filter hash.
1015 	 *
1016 	 * XXX Is 0 the right value when promiscuous is off?  This hw feature
1017 	 * seems to support the concept of MAC address aliases, does such a
1018 	 * thing even exist?
1019 	 */
1020 	if ((if_getflags(ifp) & IFF_PROMISC))
1021 		ihash = 0xffffffffffffffffLLU;
1022 	else {
1023 		ihash = 0;
1024 	}
1025 	WR4(sc, FEC_IAUR_REG, (uint32_t)(ihash >> 32));
1026 	WR4(sc, FEC_IALR_REG, (uint32_t)ihash);
1027 
1028 	/*
1029 	 * Set the primary address.
1030 	 */
1031 	eaddr = if_getlladdr(ifp);
1032 	WR4(sc, FEC_PALR_REG, (eaddr[0] << 24) | (eaddr[1] << 16) |
1033 	    (eaddr[2] <<  8) | eaddr[3]);
1034 	WR4(sc, FEC_PAUR_REG, (eaddr[4] << 24) | (eaddr[5] << 16));
1035 }
1036 
1037 static void
1038 ffec_stop_locked(struct ffec_softc *sc)
1039 {
1040 	if_t ifp;
1041 	struct ffec_hwdesc *desc;
1042 	struct ffec_bufmap *bmap;
1043 	int idx;
1044 
1045 	FFEC_ASSERT_LOCKED(sc);
1046 
1047 	ifp = sc->ifp;
1048 	if_setdrvflagbits(ifp, 0, (IFF_DRV_RUNNING | IFF_DRV_OACTIVE));
1049 	sc->tx_watchdog_count = 0;
1050 
1051 	/*
1052 	 * Stop the hardware, mask all interrupts, and clear all current
1053 	 * interrupt status bits.
1054 	 */
1055 	WR4(sc, FEC_ECR_REG, RD4(sc, FEC_ECR_REG) & ~FEC_ECR_ETHEREN);
1056 	WR4(sc, FEC_IEM_REG, 0x00000000);
1057 	WR4(sc, FEC_IER_REG, 0xffffffff);
1058 
1059 	/*
1060 	 * Stop the media-check callout.  Do not use callout_drain() because
1061 	 * we're holding a mutex the callout acquires, and if it's currently
1062 	 * waiting to acquire it, we'd deadlock.  If it is waiting now, the
1063 	 * ffec_tick() routine will return without doing anything when it sees
1064 	 * that IFF_DRV_RUNNING is not set, so avoiding callout_drain() is safe.
1065 	 */
1066 	callout_stop(&sc->ffec_callout);
1067 
1068 	/*
1069 	 * Discard all untransmitted buffers.  Each buffer is simply freed;
1070 	 * it's as if the bits were transmitted and then lost on the wire.
1071 	 *
1072 	 * XXX Is this right?  Or should we use IFQ_DRV_PREPEND() to put them
1073 	 * back on the queue for when we get restarted later?
1074 	 */
1075 	idx = sc->tx_idx_tail;
1076 	while (idx != sc->tx_idx_head) {
1077 		desc = &sc->txdesc_ring[idx];
1078 		bmap = &sc->txbuf_map[idx];
1079 		if (desc->buf_paddr != 0) {
1080 			bus_dmamap_unload(sc->txbuf_tag, bmap->map);
1081 			m_freem(bmap->mbuf);
1082 			bmap->mbuf = NULL;
1083 			ffec_setup_txdesc(sc, idx, 0, 0);
1084 		}
1085 		idx = next_txidx(sc, idx);
1086 	}
1087 
1088 	/*
1089 	 * Discard all unprocessed receive buffers.  This amounts to just
1090 	 * pretending that nothing ever got received into them.  We reuse the
1091 	 * mbuf already mapped for each desc, simply turning the EMPTY flags
1092 	 * back on so they'll get reused when we start up again.
1093 	 */
1094 	for (idx = 0; idx < RX_DESC_COUNT; ++idx) {
1095 		desc = &sc->rxdesc_ring[idx];
1096 		ffec_setup_rxdesc(sc, idx, desc->buf_paddr);
1097 	}
1098 }
1099 
1100 static void
1101 ffec_init_locked(struct ffec_softc *sc)
1102 {
1103 	if_t ifp = sc->ifp;
1104 	uint32_t maxbuf, maxfl, regval;
1105 
1106 	FFEC_ASSERT_LOCKED(sc);
1107 
1108 	/*
1109 	 * The hardware has a limit of 0x7ff as the max frame length (see
1110 	 * comments for MRBR below), and we use mbuf clusters as receive
1111 	 * buffers, and we currently are designed to receive an entire frame
1112 	 * into a single buffer.
1113 	 *
1114 	 * We start with a MCLBYTES-sized cluster, but we have to offset into
1115 	 * the buffer by ETHER_ALIGN to make room for post-receive re-alignment,
1116 	 * and then that value has to be rounded up to the hardware's DMA
1117 	 * alignment requirements, so all in all our buffer is that much smaller
1118 	 * than MCLBYTES.
1119 	 *
1120 	 * The resulting value is used as the frame truncation length and the
1121 	 * max buffer receive buffer size for now.  It'll become more complex
1122 	 * when we support jumbo frames and receiving fragments of them into
1123 	 * separate buffers.
1124 	 */
1125 	maxbuf = MCLBYTES - roundup(ETHER_ALIGN, sc->rxbuf_align);
1126 	maxfl = min(maxbuf, 0x7ff);
1127 
1128 	if (if_getdrvflags(ifp) & IFF_DRV_RUNNING)
1129 		return;
1130 
1131 	/* Mask all interrupts and clear all current interrupt status bits. */
1132 	WR4(sc, FEC_IEM_REG, 0x00000000);
1133 	WR4(sc, FEC_IER_REG, 0xffffffff);
1134 
1135 	/*
1136 	 * Go set up palr/puar, galr/gaur, ialr/iaur.
1137 	 */
1138 	ffec_setup_rxfilter(sc);
1139 
1140 	/*
1141 	 * TFWR - Transmit FIFO watermark register.
1142 	 *
1143 	 * Set the transmit fifo watermark register to "store and forward" mode
1144 	 * and also set a threshold of 128 bytes in the fifo before transmission
1145 	 * of a frame begins (to avoid dma underruns).  Recent FEC hardware
1146 	 * supports STRFWD and when that bit is set, the watermark level in the
1147 	 * low bits is ignored.  Older hardware doesn't have STRFWD, but writing
1148 	 * to that bit is innocuous, and the TWFR bits get used instead.
1149 	 */
1150 	WR4(sc, FEC_TFWR_REG, FEC_TFWR_STRFWD | FEC_TFWR_TWFR_128BYTE);
1151 
1152 	/* RCR - Receive control register.
1153 	 *
1154 	 * Set max frame length + clean out anything left from u-boot.
1155 	 */
1156 	WR4(sc, FEC_RCR_REG, (maxfl << FEC_RCR_MAX_FL_SHIFT));
1157 
1158 	/*
1159 	 * TCR - Transmit control register.
1160 	 *
1161 	 * Clean out anything left from u-boot.  Any necessary values are set in
1162 	 * ffec_miibus_statchg() based on the media type.
1163 	 */
1164 	WR4(sc, FEC_TCR_REG, 0);
1165 
1166 	/*
1167 	 * OPD - Opcode/pause duration.
1168 	 *
1169 	 * XXX These magic numbers come from u-boot.
1170 	 */
1171 	WR4(sc, FEC_OPD_REG, 0x00010020);
1172 
1173 	/*
1174 	 * FRSR - Fifo receive start register.
1175 	 *
1176 	 * This register does not exist on imx6, it is present on earlier
1177 	 * hardware. The u-boot code sets this to a non-default value that's 32
1178 	 * bytes larger than the default, with no clue as to why.  The default
1179 	 * value should work fine, so there's no code to init it here.
1180 	 */
1181 
1182 	/*
1183 	 *  MRBR - Max RX buffer size.
1184 	 *
1185 	 *  Note: For hardware prior to imx6 this value cannot exceed 0x07ff,
1186 	 *  but the datasheet says no such thing for imx6.  On the imx6, setting
1187 	 *  this to 2K without setting EN1588 resulted in a crazy runaway
1188 	 *  receive loop in the hardware, where every rx descriptor in the ring
1189 	 *  had its EMPTY flag cleared, no completion or error flags set, and a
1190 	 *  length of zero.  I think maybe you can only exceed it when EN1588 is
1191 	 *  set, like maybe that's what enables jumbo frames, because in general
1192 	 *  the EN1588 flag seems to be the "enable new stuff" vs. "be legacy-
1193 	 *  compatible" flag.
1194 	 */
1195 	WR4(sc, FEC_MRBR_REG, maxfl << FEC_MRBR_R_BUF_SIZE_SHIFT);
1196 
1197 	/*
1198 	 * FTRL - Frame truncation length.
1199 	 *
1200 	 * Must be greater than or equal to the value set in FEC_RCR_MAXFL.
1201 	 */
1202 	WR4(sc, FEC_FTRL_REG, maxfl);
1203 
1204 	/*
1205 	 * RDSR / TDSR descriptor ring pointers.
1206 	 *
1207 	 * When we turn on ECR_ETHEREN at the end, the hardware zeroes its
1208 	 * internal current descriptor index values for both rings, so we zero
1209 	 * our index values as well.
1210 	 */
1211 	sc->rx_idx = 0;
1212 	sc->tx_idx_head = sc->tx_idx_tail = 0;
1213 	sc->txcount = 0;
1214 	WR4(sc, FEC_RDSR_REG, sc->rxdesc_ring_paddr);
1215 	WR4(sc, FEC_TDSR_REG, sc->txdesc_ring_paddr);
1216 
1217 	/*
1218 	 * EIM - interrupt mask register.
1219 	 *
1220 	 * We always enable the same set of interrupts while running; unlike
1221 	 * some drivers there's no need to change the mask on the fly depending
1222 	 * on what operations are in progress.
1223 	 */
1224 	WR4(sc, FEC_IEM_REG, FEC_IER_TXF | FEC_IER_RXF | FEC_IER_EBERR);
1225 
1226 	/*
1227 	 * MIBC - MIB control (hardware stats); clear all statistics regs, then
1228 	 * enable collection of statistics.
1229 	 */
1230 	regval = RD4(sc, FEC_MIBC_REG);
1231 	WR4(sc, FEC_MIBC_REG, regval | FEC_MIBC_DIS);
1232 	ffec_clear_stats(sc);
1233 	WR4(sc, FEC_MIBC_REG, regval & ~FEC_MIBC_DIS);
1234 
1235 	if (sc->fecflags & FECFLAG_RACC) {
1236 		/*
1237 		 * RACC - Receive Accelerator Function Configuration.
1238 		 */
1239 		regval = RD4(sc, FEC_RACC_REG);
1240 		WR4(sc, FEC_RACC_REG, regval | FEC_RACC_SHIFT16);
1241 	}
1242 
1243 	/*
1244 	 * ECR - Ethernet control register.
1245 	 *
1246 	 * This must happen after all the other config registers are set.  If
1247 	 * we're running on little-endian hardware, also set the flag for byte-
1248 	 * swapping descriptor ring entries.  This flag doesn't exist on older
1249 	 * hardware, but it can be safely set -- the bit position it occupies
1250 	 * was unused.
1251 	 */
1252 	regval = RD4(sc, FEC_ECR_REG);
1253 #if _BYTE_ORDER == _LITTLE_ENDIAN
1254 	regval |= FEC_ECR_DBSWP;
1255 #endif
1256 	regval |= FEC_ECR_ETHEREN;
1257 	WR4(sc, FEC_ECR_REG, regval);
1258 
1259 	if_setdrvflagbits(ifp, IFF_DRV_RUNNING, 0);
1260 
1261        /*
1262 	* Call mii_mediachg() which will call back into ffec_miibus_statchg() to
1263 	* set up the remaining config registers based on the current media.
1264 	*/
1265 	mii_mediachg(sc->mii_softc);
1266 	callout_reset(&sc->ffec_callout, hz, ffec_tick, sc);
1267 
1268 	/*
1269 	 * Tell the hardware that receive buffers are available.  They were made
1270 	 * available in ffec_attach() or ffec_stop().
1271 	 */
1272 	WR4(sc, FEC_RDAR_REG, FEC_RDAR_RDAR);
1273 }
1274 
1275 static void
1276 ffec_init(void *if_softc)
1277 {
1278 	struct ffec_softc *sc = if_softc;
1279 
1280 	FFEC_LOCK(sc);
1281 	ffec_init_locked(sc);
1282 	FFEC_UNLOCK(sc);
1283 }
1284 
1285 static void
1286 ffec_intr(void *arg)
1287 {
1288 	struct ffec_softc *sc;
1289 	uint32_t ier;
1290 
1291 	sc = arg;
1292 
1293 	FFEC_LOCK(sc);
1294 
1295 	ier = RD4(sc, FEC_IER_REG);
1296 
1297 	if (ier & FEC_IER_TXF) {
1298 		WR4(sc, FEC_IER_REG, FEC_IER_TXF);
1299 		ffec_txfinish_locked(sc);
1300 	}
1301 
1302 	if (ier & FEC_IER_RXF) {
1303 		WR4(sc, FEC_IER_REG, FEC_IER_RXF);
1304 		ffec_rxfinish_locked(sc);
1305 	}
1306 
1307 	/*
1308 	 * We actually don't care about most errors, because the hardware copes
1309 	 * with them just fine, discarding the incoming bad frame, or forcing a
1310 	 * bad CRC onto an outgoing bad frame, and counting the errors in the
1311 	 * stats registers.  The one that really matters is EBERR (DMA bus
1312 	 * error) because the hardware automatically clears ECR[ETHEREN] and we
1313 	 * have to restart it here.  It should never happen.
1314 	 */
1315 	if (ier & FEC_IER_EBERR) {
1316 		WR4(sc, FEC_IER_REG, FEC_IER_EBERR);
1317 		device_printf(sc->dev,
1318 		    "Ethernet DMA error, restarting controller.\n");
1319 		ffec_stop_locked(sc);
1320 		ffec_init_locked(sc);
1321 	}
1322 
1323 	FFEC_UNLOCK(sc);
1324 
1325 }
1326 
1327 static int
1328 ffec_ioctl(if_t ifp, u_long cmd, caddr_t data)
1329 {
1330 	struct ffec_softc *sc;
1331 	struct mii_data *mii;
1332 	struct ifreq *ifr;
1333 	int mask, error;
1334 
1335 	sc = if_getsoftc(ifp);
1336 	ifr = (struct ifreq *)data;
1337 
1338 	error = 0;
1339 	switch (cmd) {
1340 	case SIOCSIFFLAGS:
1341 		FFEC_LOCK(sc);
1342 		if (if_getflags(ifp) & IFF_UP) {
1343 			if (if_getdrvflags(ifp) & IFF_DRV_RUNNING) {
1344 				if ((if_getflags(ifp) ^ sc->if_flags) &
1345 				    (IFF_PROMISC | IFF_ALLMULTI))
1346 					ffec_setup_rxfilter(sc);
1347 			} else {
1348 				if (!sc->is_detaching)
1349 					ffec_init_locked(sc);
1350 			}
1351 		} else {
1352 			if (if_getdrvflags(ifp) & IFF_DRV_RUNNING)
1353 				ffec_stop_locked(sc);
1354 		}
1355 		sc->if_flags = if_getflags(ifp);
1356 		FFEC_UNLOCK(sc);
1357 		break;
1358 
1359 	case SIOCADDMULTI:
1360 	case SIOCDELMULTI:
1361 		if (if_getdrvflags(ifp) & IFF_DRV_RUNNING) {
1362 			FFEC_LOCK(sc);
1363 			ffec_setup_rxfilter(sc);
1364 			FFEC_UNLOCK(sc);
1365 		}
1366 		break;
1367 
1368 	case SIOCSIFMEDIA:
1369 	case SIOCGIFMEDIA:
1370 		mii = sc->mii_softc;
1371 		error = ifmedia_ioctl(ifp, ifr, &mii->mii_media, cmd);
1372 		break;
1373 
1374 	case SIOCSIFCAP:
1375 		mask = if_getcapenable(ifp) ^ ifr->ifr_reqcap;
1376 		if (mask & IFCAP_VLAN_MTU) {
1377 			/* No work to do except acknowledge the change took. */
1378 			if_togglecapenable(ifp, IFCAP_VLAN_MTU);
1379 		}
1380 		break;
1381 
1382 	default:
1383 		error = ether_ioctl(ifp, cmd, data);
1384 		break;
1385 	}
1386 
1387 	return (error);
1388 }
1389 
1390 static int
1391 ffec_detach(device_t dev)
1392 {
1393 	struct ffec_softc *sc;
1394 	bus_dmamap_t map;
1395 	int idx, irq;
1396 
1397 	/*
1398 	 * NB: This function can be called internally to unwind a failure to
1399 	 * attach. Make sure a resource got allocated/created before destroying.
1400 	 */
1401 
1402 	sc = device_get_softc(dev);
1403 
1404 	if (sc->is_attached) {
1405 		FFEC_LOCK(sc);
1406 		sc->is_detaching = true;
1407 		ffec_stop_locked(sc);
1408 		FFEC_UNLOCK(sc);
1409 		callout_drain(&sc->ffec_callout);
1410 		ether_ifdetach(sc->ifp);
1411 	}
1412 
1413 	/* XXX no miibus detach? */
1414 
1415 	/* Clean up RX DMA resources and free mbufs. */
1416 	for (idx = 0; idx < RX_DESC_COUNT; ++idx) {
1417 		if ((map = sc->rxbuf_map[idx].map) != NULL) {
1418 			bus_dmamap_unload(sc->rxbuf_tag, map);
1419 			bus_dmamap_destroy(sc->rxbuf_tag, map);
1420 			m_freem(sc->rxbuf_map[idx].mbuf);
1421 		}
1422 	}
1423 	if (sc->rxbuf_tag != NULL)
1424 		bus_dma_tag_destroy(sc->rxbuf_tag);
1425 	if (sc->rxdesc_map != NULL) {
1426 		bus_dmamap_unload(sc->rxdesc_tag, sc->rxdesc_map);
1427 		bus_dmamem_free(sc->rxdesc_tag, sc->rxdesc_ring,
1428 		    sc->rxdesc_map);
1429 	}
1430 	if (sc->rxdesc_tag != NULL)
1431 		bus_dma_tag_destroy(sc->rxdesc_tag);
1432 
1433 	/* Clean up TX DMA resources. */
1434 	for (idx = 0; idx < TX_DESC_COUNT; ++idx) {
1435 		if ((map = sc->txbuf_map[idx].map) != NULL) {
1436 			/* TX maps are already unloaded. */
1437 			bus_dmamap_destroy(sc->txbuf_tag, map);
1438 		}
1439 	}
1440 	if (sc->txbuf_tag != NULL)
1441 		bus_dma_tag_destroy(sc->txbuf_tag);
1442 	if (sc->txdesc_map != NULL) {
1443 		bus_dmamap_unload(sc->txdesc_tag, sc->txdesc_map);
1444 		bus_dmamem_free(sc->txdesc_tag, sc->txdesc_ring,
1445 		    sc->txdesc_map);
1446 	}
1447 	if (sc->txdesc_tag != NULL)
1448 		bus_dma_tag_destroy(sc->txdesc_tag);
1449 
1450 	/* Release bus resources. */
1451 	for (irq = 0; irq < MAX_IRQ_COUNT; ++irq) {
1452 		if (sc->intr_cookie[irq] != NULL) {
1453 			bus_teardown_intr(dev, sc->irq_res[irq],
1454 			    sc->intr_cookie[irq]);
1455 		}
1456 	}
1457 	bus_release_resources(dev, irq_res_spec, sc->irq_res);
1458 
1459 	if (sc->mem_res != NULL)
1460 		bus_release_resource(dev, SYS_RES_MEMORY, 0, sc->mem_res);
1461 
1462 	FFEC_LOCK_DESTROY(sc);
1463 	return (0);
1464 }
1465 
1466 static int
1467 ffec_attach(device_t dev)
1468 {
1469 	struct ffec_softc *sc;
1470 	if_t ifp = NULL;
1471 	struct mbuf *m;
1472 	void *dummy;
1473 	uintptr_t typeflags;
1474 	phandle_t ofw_node;
1475 	uint32_t idx, mscr;
1476 	int error, phynum, rid, irq;
1477 	uint8_t eaddr[ETHER_ADDR_LEN];
1478 
1479 	sc = device_get_softc(dev);
1480 	sc->dev = dev;
1481 
1482 	FFEC_LOCK_INIT(sc);
1483 
1484 	/*
1485 	 * There are differences in the implementation and features of the FEC
1486 	 * hardware on different SoCs, so figure out what type we are.
1487 	 */
1488 	typeflags = ofw_bus_search_compatible(dev, compat_data)->ocd_data;
1489 	sc->fectype = (uint8_t)(typeflags & FECTYPE_MASK);
1490 	sc->fecflags = (uint32_t)(typeflags & ~FECTYPE_MASK);
1491 
1492 	if (sc->fecflags & FECFLAG_AVB) {
1493 		sc->rxbuf_align = 64;
1494 		sc->txbuf_align = 1;
1495 	} else {
1496 		sc->rxbuf_align = 16;
1497 		sc->txbuf_align = 16;
1498 	}
1499 
1500 	/*
1501 	 * We have to be told what kind of electrical connection exists between
1502 	 * the MAC and PHY or we can't operate correctly.
1503 	 */
1504 	if ((ofw_node = ofw_bus_get_node(dev)) == -1) {
1505 		device_printf(dev, "Impossible: Can't find ofw bus node\n");
1506 		error = ENXIO;
1507 		goto out;
1508 	}
1509 	sc->phy_conn_type = mii_fdt_get_contype(ofw_node);
1510 	if (sc->phy_conn_type == MII_CONTYPE_UNKNOWN) {
1511 		device_printf(sc->dev, "No valid 'phy-mode' "
1512 		    "property found in FDT data for device.\n");
1513 		error = ENOATTR;
1514 		goto out;
1515 	}
1516 
1517 	callout_init_mtx(&sc->ffec_callout, &sc->mtx, 0);
1518 
1519 	/* Allocate bus resources for accessing the hardware. */
1520 	rid = 0;
1521 	sc->mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid,
1522 	    RF_ACTIVE);
1523 	if (sc->mem_res == NULL) {
1524 		device_printf(dev, "could not allocate memory resources.\n");
1525 		error = ENOMEM;
1526 		goto out;
1527 	}
1528 
1529 	error = bus_alloc_resources(dev, irq_res_spec, sc->irq_res);
1530 	if (error != 0) {
1531 		device_printf(dev, "could not allocate interrupt resources\n");
1532 		goto out;
1533 	}
1534 
1535 	/*
1536 	 * Set up TX descriptor ring, descriptors, and dma maps.
1537 	 */
1538 	error = bus_dma_tag_create(
1539 	    bus_get_dma_tag(dev),	/* Parent tag. */
1540 	    FEC_DESC_RING_ALIGN, 0,	/* alignment, boundary */
1541 	    BUS_SPACE_MAXADDR_32BIT,	/* lowaddr */
1542 	    BUS_SPACE_MAXADDR,		/* highaddr */
1543 	    NULL, NULL,			/* filter, filterarg */
1544 	    TX_DESC_SIZE, 1, 		/* maxsize, nsegments */
1545 	    TX_DESC_SIZE,		/* maxsegsize */
1546 	    0,				/* flags */
1547 	    NULL, NULL,			/* lockfunc, lockarg */
1548 	    &sc->txdesc_tag);
1549 	if (error != 0) {
1550 		device_printf(sc->dev,
1551 		    "could not create TX ring DMA tag.\n");
1552 		goto out;
1553 	}
1554 
1555 	error = bus_dmamem_alloc(sc->txdesc_tag, (void**)&sc->txdesc_ring,
1556 	    BUS_DMA_COHERENT | BUS_DMA_WAITOK | BUS_DMA_ZERO, &sc->txdesc_map);
1557 	if (error != 0) {
1558 		device_printf(sc->dev,
1559 		    "could not allocate TX descriptor ring.\n");
1560 		goto out;
1561 	}
1562 
1563 	error = bus_dmamap_load(sc->txdesc_tag, sc->txdesc_map, sc->txdesc_ring,
1564 	    TX_DESC_SIZE, ffec_get1paddr, &sc->txdesc_ring_paddr, 0);
1565 	if (error != 0) {
1566 		device_printf(sc->dev,
1567 		    "could not load TX descriptor ring map.\n");
1568 		goto out;
1569 	}
1570 
1571 	error = bus_dma_tag_create(
1572 	    bus_get_dma_tag(dev),	/* Parent tag. */
1573 	    sc->txbuf_align, 0,		/* alignment, boundary */
1574 	    BUS_SPACE_MAXADDR_32BIT,	/* lowaddr */
1575 	    BUS_SPACE_MAXADDR,		/* highaddr */
1576 	    NULL, NULL,			/* filter, filterarg */
1577 	    MCLBYTES, 1, 		/* maxsize, nsegments */
1578 	    MCLBYTES,			/* maxsegsize */
1579 	    0,				/* flags */
1580 	    NULL, NULL,			/* lockfunc, lockarg */
1581 	    &sc->txbuf_tag);
1582 	if (error != 0) {
1583 		device_printf(sc->dev,
1584 		    "could not create TX ring DMA tag.\n");
1585 		goto out;
1586 	}
1587 
1588 	for (idx = 0; idx < TX_DESC_COUNT; ++idx) {
1589 		error = bus_dmamap_create(sc->txbuf_tag, 0,
1590 		    &sc->txbuf_map[idx].map);
1591 		if (error != 0) {
1592 			device_printf(sc->dev,
1593 			    "could not create TX buffer DMA map.\n");
1594 			goto out;
1595 		}
1596 		ffec_setup_txdesc(sc, idx, 0, 0);
1597 	}
1598 
1599 	/*
1600 	 * Set up RX descriptor ring, descriptors, dma maps, and mbufs.
1601 	 */
1602 	error = bus_dma_tag_create(
1603 	    bus_get_dma_tag(dev),	/* Parent tag. */
1604 	    FEC_DESC_RING_ALIGN, 0,	/* alignment, boundary */
1605 	    BUS_SPACE_MAXADDR_32BIT,	/* lowaddr */
1606 	    BUS_SPACE_MAXADDR,		/* highaddr */
1607 	    NULL, NULL,			/* filter, filterarg */
1608 	    RX_DESC_SIZE, 1, 		/* maxsize, nsegments */
1609 	    RX_DESC_SIZE,		/* maxsegsize */
1610 	    0,				/* flags */
1611 	    NULL, NULL,			/* lockfunc, lockarg */
1612 	    &sc->rxdesc_tag);
1613 	if (error != 0) {
1614 		device_printf(sc->dev,
1615 		    "could not create RX ring DMA tag.\n");
1616 		goto out;
1617 	}
1618 
1619 	error = bus_dmamem_alloc(sc->rxdesc_tag, (void **)&sc->rxdesc_ring,
1620 	    BUS_DMA_COHERENT | BUS_DMA_WAITOK | BUS_DMA_ZERO, &sc->rxdesc_map);
1621 	if (error != 0) {
1622 		device_printf(sc->dev,
1623 		    "could not allocate RX descriptor ring.\n");
1624 		goto out;
1625 	}
1626 
1627 	error = bus_dmamap_load(sc->rxdesc_tag, sc->rxdesc_map, sc->rxdesc_ring,
1628 	    RX_DESC_SIZE, ffec_get1paddr, &sc->rxdesc_ring_paddr, 0);
1629 	if (error != 0) {
1630 		device_printf(sc->dev,
1631 		    "could not load RX descriptor ring map.\n");
1632 		goto out;
1633 	}
1634 
1635 	error = bus_dma_tag_create(
1636 	    bus_get_dma_tag(dev),	/* Parent tag. */
1637 	    1, 0,			/* alignment, boundary */
1638 	    BUS_SPACE_MAXADDR_32BIT,	/* lowaddr */
1639 	    BUS_SPACE_MAXADDR,		/* highaddr */
1640 	    NULL, NULL,			/* filter, filterarg */
1641 	    MCLBYTES, 1, 		/* maxsize, nsegments */
1642 	    MCLBYTES,			/* maxsegsize */
1643 	    0,				/* flags */
1644 	    NULL, NULL,			/* lockfunc, lockarg */
1645 	    &sc->rxbuf_tag);
1646 	if (error != 0) {
1647 		device_printf(sc->dev,
1648 		    "could not create RX buf DMA tag.\n");
1649 		goto out;
1650 	}
1651 
1652 	for (idx = 0; idx < RX_DESC_COUNT; ++idx) {
1653 		error = bus_dmamap_create(sc->rxbuf_tag, 0,
1654 		    &sc->rxbuf_map[idx].map);
1655 		if (error != 0) {
1656 			device_printf(sc->dev,
1657 			    "could not create RX buffer DMA map.\n");
1658 			goto out;
1659 		}
1660 		if ((m = ffec_alloc_mbufcl(sc)) == NULL) {
1661 			device_printf(dev, "Could not alloc mbuf\n");
1662 			error = ENOMEM;
1663 			goto out;
1664 		}
1665 		if ((error = ffec_setup_rxbuf(sc, idx, m)) != 0) {
1666 			device_printf(sc->dev,
1667 			    "could not create new RX buffer.\n");
1668 			goto out;
1669 		}
1670 	}
1671 
1672 	/* Try to get the MAC address from the hardware before resetting it. */
1673 	ffec_get_hwaddr(sc, eaddr);
1674 
1675 	/*
1676 	 * Reset the hardware.  Disables all interrupts.
1677 	 *
1678 	 * When the FEC is connected to the AXI bus (indicated by AVB flag), a
1679 	 * MAC reset while a bus transaction is pending can hang the bus.
1680 	 * Instead of resetting, turn off the ENABLE bit, which allows the
1681 	 * hardware to complete any in-progress transfers (appending a bad CRC
1682 	 * to any partial packet) and release the AXI bus.  This could probably
1683 	 * be done unconditionally for all hardware variants, but that hasn't
1684 	 * been tested.
1685 	 */
1686 	if (sc->fecflags & FECFLAG_AVB)
1687 		WR4(sc, FEC_ECR_REG, 0);
1688 	else
1689 		WR4(sc, FEC_ECR_REG, FEC_ECR_RESET);
1690 
1691 	/* Setup interrupt handler. */
1692 	for (irq = 0; irq < MAX_IRQ_COUNT; ++irq) {
1693 		if (sc->irq_res[irq] != NULL) {
1694 			error = bus_setup_intr(dev, sc->irq_res[irq],
1695 			    INTR_TYPE_NET | INTR_MPSAFE, NULL, ffec_intr, sc,
1696 			    &sc->intr_cookie[irq]);
1697 			if (error != 0) {
1698 				device_printf(dev,
1699 				    "could not setup interrupt handler.\n");
1700 				goto out;
1701 			}
1702 		}
1703 	}
1704 
1705 	/*
1706 	 * Set up the PHY control register.
1707 	 *
1708 	 * Speed formula for ENET is md_clock = mac_clock / ((N + 1) * 2).
1709 	 * Speed formula for FEC is  md_clock = mac_clock / (N * 2)
1710 	 *
1711 	 * XXX - Revisit this...
1712 	 *
1713 	 * For a Wandboard imx6 (ENET) I was originally using 4, but the uboot
1714 	 * code uses 10.  Both values seem to work, but I suspect many modern
1715 	 * PHY parts can do mdio at speeds far above the standard 2.5 MHz.
1716 	 *
1717 	 * Different imx manuals use confusingly different terminology (things
1718 	 * like "system clock" and "internal module clock") with examples that
1719 	 * use frequencies that have nothing to do with ethernet, giving the
1720 	 * vague impression that maybe the clock in question is the periphclock
1721 	 * or something.  In fact, on an imx53 development board (FEC),
1722 	 * measuring the mdio clock at the pin on the PHY and playing with
1723 	 * various divisors showed that the root speed was 66 MHz (clk_ipg_root
1724 	 * aka periphclock) and 13 was the right divisor.
1725 	 *
1726 	 * All in all, it seems likely that 13 is a safe divisor for now,
1727 	 * because if we really do need to base it on the peripheral clock
1728 	 * speed, then we need a platform-independent get-clock-freq API.
1729 	 */
1730 	mscr = 13 << FEC_MSCR_MII_SPEED_SHIFT;
1731 	if (OF_hasprop(ofw_node, "phy-disable-preamble")) {
1732 		mscr |= FEC_MSCR_DIS_PRE;
1733 		if (bootverbose)
1734 			device_printf(dev, "PHY preamble disabled\n");
1735 	}
1736 	WR4(sc, FEC_MSCR_REG, mscr);
1737 
1738 	/* Set up the ethernet interface. */
1739 	sc->ifp = ifp = if_alloc(IFT_ETHER);
1740 
1741 	if_setsoftc(ifp, sc);
1742 	if_initname(ifp, device_get_name(dev), device_get_unit(dev));
1743 	if_setflags(ifp, IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST);
1744 	if_setcapabilities(ifp, IFCAP_VLAN_MTU);
1745 	if_setcapenable(ifp, if_getcapabilities(ifp));
1746 	if_setstartfn(ifp, ffec_txstart);
1747 	if_setioctlfn(ifp, ffec_ioctl);
1748 	if_setinitfn(ifp, ffec_init);
1749 	if_setsendqlen(ifp, TX_DESC_COUNT - 1);
1750 	if_setsendqready(ifp);
1751 	if_setifheaderlen(ifp, sizeof(struct ether_vlan_header));
1752 
1753 #if 0 /* XXX The hardware keeps stats we could use for these. */
1754 	if_setlinkmib(ifp, &sc->mibdata);
1755 	if_setlinkmiblen(ifp, sizeof(sc->mibdata));
1756 #endif
1757 
1758 	/* Set up the miigasket hardware (if any). */
1759 	ffec_miigasket_setup(sc);
1760 
1761 	/* Attach the mii driver. */
1762 	if (fdt_get_phyaddr(ofw_node, dev, &phynum, &dummy) != 0) {
1763 		phynum = MII_PHY_ANY;
1764 	}
1765 	error = mii_attach(dev, &sc->miibus, ifp, ffec_media_change,
1766 	    ffec_media_status, BMSR_DEFCAPMASK, phynum, MII_OFFSET_ANY,
1767 	    (sc->fecflags & FECTYPE_MVF) ? MIIF_FORCEANEG : 0);
1768 	if (error != 0) {
1769 		device_printf(dev, "PHY attach failed\n");
1770 		goto out;
1771 	}
1772 	sc->mii_softc = device_get_softc(sc->miibus);
1773 
1774 	/* All ready to run, attach the ethernet interface. */
1775 	ether_ifattach(ifp, eaddr);
1776 	sc->is_attached = true;
1777 
1778 	error = 0;
1779 out:
1780 
1781 	if (error != 0)
1782 		ffec_detach(dev);
1783 
1784 	return (error);
1785 }
1786 
1787 static int
1788 ffec_probe(device_t dev)
1789 {
1790 	uintptr_t fectype;
1791 
1792 	if (!ofw_bus_status_okay(dev))
1793 		return (ENXIO);
1794 
1795 	fectype = ofw_bus_search_compatible(dev, compat_data)->ocd_data;
1796 	if (fectype == FECTYPE_NONE)
1797 		return (ENXIO);
1798 
1799 	device_set_desc(dev, (fectype & FECFLAG_GBE) ?
1800 	    "Freescale Gigabit Ethernet Controller" :
1801 	    "Freescale Fast Ethernet Controller");
1802 
1803 	return (BUS_PROBE_DEFAULT);
1804 }
1805 
1806 
1807 static device_method_t ffec_methods[] = {
1808 	/* Device interface. */
1809 	DEVMETHOD(device_probe,		ffec_probe),
1810 	DEVMETHOD(device_attach,	ffec_attach),
1811 	DEVMETHOD(device_detach,	ffec_detach),
1812 
1813 /*
1814 	DEVMETHOD(device_shutdown,	ffec_shutdown),
1815 	DEVMETHOD(device_suspend,	ffec_suspend),
1816 	DEVMETHOD(device_resume,	ffec_resume),
1817 */
1818 
1819 	/* MII interface. */
1820 	DEVMETHOD(miibus_readreg,	ffec_miibus_readreg),
1821 	DEVMETHOD(miibus_writereg,	ffec_miibus_writereg),
1822 	DEVMETHOD(miibus_statchg,	ffec_miibus_statchg),
1823 
1824 	DEVMETHOD_END
1825 };
1826 
1827 static driver_t ffec_driver = {
1828 	"ffec",
1829 	ffec_methods,
1830 	sizeof(struct ffec_softc)
1831 };
1832 
1833 DRIVER_MODULE(ffec, simplebus, ffec_driver, 0, 0);
1834 DRIVER_MODULE(miibus, ffec, miibus_driver, 0, 0);
1835 
1836 MODULE_DEPEND(ffec, ether, 1, 1, 1);
1837 MODULE_DEPEND(ffec, miibus, 1, 1, 1);
1838