xref: /freebsd/sys/dev/ffec/if_ffec.c (revision 783d3ff6d7fae619db8a7990b8a6387de0c677b5)
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 },
125 	{"fsl,imx7d-fec",	FECTYPE_IMX6 | FECFLAG_RACC | FECFLAG_GBE |
126 				FECFLAG_AVB },
127 	{"fsl,mvf600-fec",	FECTYPE_MVF  | FECFLAG_RACC },
128 	{"fsl,mvf-fec",		FECTYPE_MVF},
129 	{NULL,		 	FECTYPE_NONE},
130 };
131 
132 /*
133  * Driver data and defines.
134  */
135 #define	RX_DESC_COUNT	64
136 #define	RX_DESC_SIZE	(sizeof(struct ffec_hwdesc) * RX_DESC_COUNT)
137 #define	TX_DESC_COUNT	64
138 #define	TX_DESC_SIZE	(sizeof(struct ffec_hwdesc) * TX_DESC_COUNT)
139 
140 #define	WATCHDOG_TIMEOUT_SECS	5
141 
142 #define	MAX_IRQ_COUNT 3
143 
144 struct ffec_bufmap {
145 	struct mbuf	*mbuf;
146 	bus_dmamap_t	map;
147 };
148 
149 struct ffec_softc {
150 	device_t		dev;
151 	device_t		miibus;
152 	struct mii_data *	mii_softc;
153 	if_t			ifp;
154 	int			if_flags;
155 	struct mtx		mtx;
156 	struct resource		*irq_res[MAX_IRQ_COUNT];
157 	struct resource		*mem_res;
158 	void *			intr_cookie[MAX_IRQ_COUNT];
159 	struct callout		ffec_callout;
160 	mii_contype_t		phy_conn_type;
161 	uint32_t		fecflags;
162 	uint8_t			fectype;
163 	boolean_t		link_is_up;
164 	boolean_t		is_attached;
165 	boolean_t		is_detaching;
166 	int			tx_watchdog_count;
167 	int			rxbuf_align;
168 	int			txbuf_align;
169 
170 	bus_dma_tag_t		rxdesc_tag;
171 	bus_dmamap_t		rxdesc_map;
172 	struct ffec_hwdesc	*rxdesc_ring;
173 	bus_addr_t		rxdesc_ring_paddr;
174 	bus_dma_tag_t		rxbuf_tag;
175 	struct ffec_bufmap	rxbuf_map[RX_DESC_COUNT];
176 	uint32_t		rx_idx;
177 
178 	bus_dma_tag_t		txdesc_tag;
179 	bus_dmamap_t		txdesc_map;
180 	struct ffec_hwdesc	*txdesc_ring;
181 	bus_addr_t		txdesc_ring_paddr;
182 	bus_dma_tag_t		txbuf_tag;
183 	struct ffec_bufmap	txbuf_map[TX_DESC_COUNT];
184 	uint32_t		tx_idx_head;
185 	uint32_t		tx_idx_tail;
186 	int			txcount;
187 };
188 
189 static struct resource_spec irq_res_spec[MAX_IRQ_COUNT + 1] = {
190 	{ SYS_RES_IRQ,		0,	RF_ACTIVE },
191 	{ SYS_RES_IRQ,		1,	RF_ACTIVE | RF_OPTIONAL },
192 	{ SYS_RES_IRQ,		2,	RF_ACTIVE | RF_OPTIONAL },
193 	RESOURCE_SPEC_END
194 };
195 
196 #define	FFEC_LOCK(sc)			mtx_lock(&(sc)->mtx)
197 #define	FFEC_UNLOCK(sc)			mtx_unlock(&(sc)->mtx)
198 #define	FFEC_LOCK_INIT(sc)		mtx_init(&(sc)->mtx, \
199 	    device_get_nameunit((sc)->dev), MTX_NETWORK_LOCK, MTX_DEF)
200 #define	FFEC_LOCK_DESTROY(sc)		mtx_destroy(&(sc)->mtx);
201 #define	FFEC_ASSERT_LOCKED(sc)		mtx_assert(&(sc)->mtx, MA_OWNED);
202 #define	FFEC_ASSERT_UNLOCKED(sc)	mtx_assert(&(sc)->mtx, MA_NOTOWNED);
203 
204 static void ffec_init_locked(struct ffec_softc *sc);
205 static void ffec_stop_locked(struct ffec_softc *sc);
206 static void ffec_txstart_locked(struct ffec_softc *sc);
207 static void ffec_txfinish_locked(struct ffec_softc *sc);
208 
209 static inline uint16_t
210 RD2(struct ffec_softc *sc, bus_size_t off)
211 {
212 
213 	return (bus_read_2(sc->mem_res, off));
214 }
215 
216 static inline void
217 WR2(struct ffec_softc *sc, bus_size_t off, uint16_t val)
218 {
219 
220 	bus_write_2(sc->mem_res, off, val);
221 }
222 
223 static inline uint32_t
224 RD4(struct ffec_softc *sc, bus_size_t off)
225 {
226 
227 	return (bus_read_4(sc->mem_res, off));
228 }
229 
230 static inline void
231 WR4(struct ffec_softc *sc, bus_size_t off, uint32_t val)
232 {
233 
234 	bus_write_4(sc->mem_res, off, val);
235 }
236 
237 static inline uint32_t
238 next_rxidx(struct ffec_softc *sc, uint32_t curidx)
239 {
240 
241 	return ((curidx == RX_DESC_COUNT - 1) ? 0 : curidx + 1);
242 }
243 
244 static inline uint32_t
245 next_txidx(struct ffec_softc *sc, uint32_t curidx)
246 {
247 
248 	return ((curidx == TX_DESC_COUNT - 1) ? 0 : curidx + 1);
249 }
250 
251 static void
252 ffec_get1paddr(void *arg, bus_dma_segment_t *segs, int nsegs, int error)
253 {
254 
255 	if (error != 0)
256 		return;
257 	*(bus_addr_t *)arg = segs[0].ds_addr;
258 }
259 
260 static void
261 ffec_miigasket_setup(struct ffec_softc *sc)
262 {
263 	uint32_t ifmode;
264 
265 	/*
266 	 * We only need the gasket for MII and RMII connections on certain SoCs.
267 	 */
268 
269 	switch (sc->fectype)
270 	{
271 	case FECTYPE_IMX53:
272 		break;
273 	default:
274 		return;
275 	}
276 
277 	switch (sc->phy_conn_type)
278 	{
279 	case MII_CONTYPE_MII:
280 		ifmode = 0;
281 		break;
282 	case MII_CONTYPE_RMII:
283 		ifmode = FEC_MIIGSK_CFGR_IF_MODE_RMII;
284 		break;
285 	default:
286 		return;
287 	}
288 
289 	/*
290 	 * Disable the gasket, configure for either MII or RMII, then enable.
291 	 */
292 
293 	WR2(sc, FEC_MIIGSK_ENR, 0);
294 	while (RD2(sc, FEC_MIIGSK_ENR) & FEC_MIIGSK_ENR_READY)
295 		continue;
296 
297 	WR2(sc, FEC_MIIGSK_CFGR, ifmode);
298 
299 	WR2(sc, FEC_MIIGSK_ENR, FEC_MIIGSK_ENR_EN);
300 	while (!(RD2(sc, FEC_MIIGSK_ENR) & FEC_MIIGSK_ENR_READY))
301 		continue;
302 }
303 
304 static boolean_t
305 ffec_miibus_iowait(struct ffec_softc *sc)
306 {
307 	uint32_t timeout;
308 
309 	for (timeout = 10000; timeout != 0; --timeout)
310 		if (RD4(sc, FEC_IER_REG) & FEC_IER_MII)
311 			return (true);
312 
313 	return (false);
314 }
315 
316 static int
317 ffec_miibus_readreg(device_t dev, int phy, int reg)
318 {
319 	struct ffec_softc *sc;
320 	int val;
321 
322 	sc = device_get_softc(dev);
323 
324 	WR4(sc, FEC_IER_REG, FEC_IER_MII);
325 
326 	WR4(sc, FEC_MMFR_REG, FEC_MMFR_OP_READ |
327 	    FEC_MMFR_ST_VALUE | FEC_MMFR_TA_VALUE |
328 	    ((phy << FEC_MMFR_PA_SHIFT) & FEC_MMFR_PA_MASK) |
329 	    ((reg << FEC_MMFR_RA_SHIFT) & FEC_MMFR_RA_MASK));
330 
331 	if (!ffec_miibus_iowait(sc)) {
332 		device_printf(dev, "timeout waiting for mii read\n");
333 		return (-1); /* All-ones is a symptom of bad mdio. */
334 	}
335 
336 	val = RD4(sc, FEC_MMFR_REG) & FEC_MMFR_DATA_MASK;
337 
338 	return (val);
339 }
340 
341 static int
342 ffec_miibus_writereg(device_t dev, int phy, int reg, int val)
343 {
344 	struct ffec_softc *sc;
345 
346 	sc = device_get_softc(dev);
347 
348 	WR4(sc, FEC_IER_REG, FEC_IER_MII);
349 
350 	WR4(sc, FEC_MMFR_REG, FEC_MMFR_OP_WRITE |
351 	    FEC_MMFR_ST_VALUE | FEC_MMFR_TA_VALUE |
352 	    ((phy << FEC_MMFR_PA_SHIFT) & FEC_MMFR_PA_MASK) |
353 	    ((reg << FEC_MMFR_RA_SHIFT) & FEC_MMFR_RA_MASK) |
354 	    (val & FEC_MMFR_DATA_MASK));
355 
356 	if (!ffec_miibus_iowait(sc)) {
357 		device_printf(dev, "timeout waiting for mii write\n");
358 		return (-1);
359 	}
360 
361 	return (0);
362 }
363 
364 static void
365 ffec_miibus_statchg(device_t dev)
366 {
367 	struct ffec_softc *sc;
368 	struct mii_data *mii;
369 	uint32_t ecr, rcr, tcr;
370 
371 	/*
372 	 * Called by the MII bus driver when the PHY establishes link to set the
373 	 * MAC interface registers.
374 	 */
375 
376 	sc = device_get_softc(dev);
377 
378 	FFEC_ASSERT_LOCKED(sc);
379 
380 	mii = sc->mii_softc;
381 
382 	if (mii->mii_media_status & IFM_ACTIVE)
383 		sc->link_is_up = true;
384 	else
385 		sc->link_is_up = false;
386 
387 	ecr = RD4(sc, FEC_ECR_REG) & ~FEC_ECR_SPEED;
388 	rcr = RD4(sc, FEC_RCR_REG) & ~(FEC_RCR_RMII_10T | FEC_RCR_RMII_MODE |
389 	    FEC_RCR_RGMII_EN | FEC_RCR_DRT | FEC_RCR_FCE);
390 	tcr = RD4(sc, FEC_TCR_REG) & ~FEC_TCR_FDEN;
391 
392 	rcr |= FEC_RCR_MII_MODE; /* Must always be on even for R[G]MII. */
393 	switch (sc->phy_conn_type) {
394 	case MII_CONTYPE_RMII:
395 		rcr |= FEC_RCR_RMII_MODE;
396 		break;
397 	case MII_CONTYPE_RGMII:
398 	case MII_CONTYPE_RGMII_ID:
399 	case MII_CONTYPE_RGMII_RXID:
400 	case MII_CONTYPE_RGMII_TXID:
401 		rcr |= FEC_RCR_RGMII_EN;
402 		break;
403 	default:
404 		break;
405 	}
406 
407 	switch (IFM_SUBTYPE(mii->mii_media_active)) {
408 	case IFM_1000_T:
409 	case IFM_1000_SX:
410 		ecr |= FEC_ECR_SPEED;
411 		break;
412 	case IFM_100_TX:
413 		/* Not-FEC_ECR_SPEED + not-FEC_RCR_RMII_10T means 100TX */
414 		break;
415 	case IFM_10_T:
416 		rcr |= FEC_RCR_RMII_10T;
417 		break;
418 	case IFM_NONE:
419 		sc->link_is_up = false;
420 		return;
421 	default:
422 		sc->link_is_up = false;
423 		device_printf(dev, "Unsupported media %u\n",
424 		    IFM_SUBTYPE(mii->mii_media_active));
425 		return;
426 	}
427 
428 	if ((IFM_OPTIONS(mii->mii_media_active) & IFM_FDX) != 0)
429 		tcr |= FEC_TCR_FDEN;
430 	else
431 		rcr |= FEC_RCR_DRT;
432 
433 	if ((IFM_OPTIONS(mii->mii_media_active) & IFM_FLOW) != 0)
434 		rcr |= FEC_RCR_FCE;
435 
436 	WR4(sc, FEC_RCR_REG, rcr);
437 	WR4(sc, FEC_TCR_REG, tcr);
438 	WR4(sc, FEC_ECR_REG, ecr);
439 }
440 
441 static void
442 ffec_media_status(if_t  ifp, struct ifmediareq *ifmr)
443 {
444 	struct ffec_softc *sc;
445 	struct mii_data *mii;
446 
447 
448 	sc = if_getsoftc(ifp);
449 	mii = sc->mii_softc;
450 	FFEC_LOCK(sc);
451 	mii_pollstat(mii);
452 	ifmr->ifm_active = mii->mii_media_active;
453 	ifmr->ifm_status = mii->mii_media_status;
454 	FFEC_UNLOCK(sc);
455 }
456 
457 static int
458 ffec_media_change_locked(struct ffec_softc *sc)
459 {
460 
461 	return (mii_mediachg(sc->mii_softc));
462 }
463 
464 static int
465 ffec_media_change(if_t  ifp)
466 {
467 	struct ffec_softc *sc;
468 	int error;
469 
470 	sc = if_getsoftc(ifp);
471 
472 	FFEC_LOCK(sc);
473 	error = ffec_media_change_locked(sc);
474 	FFEC_UNLOCK(sc);
475 	return (error);
476 }
477 
478 static void ffec_clear_stats(struct ffec_softc *sc)
479 {
480 	uint32_t mibc;
481 
482 	mibc = RD4(sc, FEC_MIBC_REG);
483 
484 	/*
485 	 * On newer hardware the statistic regs are cleared by toggling a bit in
486 	 * the mib control register.  On older hardware the clear procedure is
487 	 * to disable statistics collection, zero the regs, then re-enable.
488 	 */
489 	if (sc->fectype == FECTYPE_IMX6 || sc->fectype == FECTYPE_MVF) {
490 		WR4(sc, FEC_MIBC_REG, mibc | FEC_MIBC_CLEAR);
491 		WR4(sc, FEC_MIBC_REG, mibc & ~FEC_MIBC_CLEAR);
492 	} else {
493 		WR4(sc, FEC_MIBC_REG, mibc | FEC_MIBC_DIS);
494 
495 		WR4(sc, FEC_IEEE_R_DROP, 0);
496 		WR4(sc, FEC_IEEE_R_MACERR, 0);
497 		WR4(sc, FEC_RMON_R_CRC_ALIGN, 0);
498 		WR4(sc, FEC_RMON_R_FRAG, 0);
499 		WR4(sc, FEC_RMON_R_JAB, 0);
500 		WR4(sc, FEC_RMON_R_MC_PKT, 0);
501 		WR4(sc, FEC_RMON_R_OVERSIZE, 0);
502 		WR4(sc, FEC_RMON_R_PACKETS, 0);
503 		WR4(sc, FEC_RMON_R_UNDERSIZE, 0);
504 		WR4(sc, FEC_RMON_T_COL, 0);
505 		WR4(sc, FEC_RMON_T_CRC_ALIGN, 0);
506 		WR4(sc, FEC_RMON_T_FRAG, 0);
507 		WR4(sc, FEC_RMON_T_JAB, 0);
508 		WR4(sc, FEC_RMON_T_MC_PKT, 0);
509 		WR4(sc, FEC_RMON_T_OVERSIZE , 0);
510 		WR4(sc, FEC_RMON_T_PACKETS, 0);
511 		WR4(sc, FEC_RMON_T_UNDERSIZE, 0);
512 
513 		WR4(sc, FEC_MIBC_REG, mibc);
514 	}
515 }
516 
517 static void
518 ffec_harvest_stats(struct ffec_softc *sc)
519 {
520 	if_t ifp;
521 
522 	ifp = sc->ifp;
523 
524 	/*
525 	 * - FEC_IEEE_R_DROP is "dropped due to invalid start frame delimiter"
526 	 *   so it's really just another type of input error.
527 	 * - FEC_IEEE_R_MACERR is "no receive fifo space"; count as input drops.
528 	 */
529 	if_inc_counter(ifp, IFCOUNTER_IPACKETS, RD4(sc, FEC_RMON_R_PACKETS));
530 	if_inc_counter(ifp, IFCOUNTER_IMCASTS, RD4(sc, FEC_RMON_R_MC_PKT));
531 	if_inc_counter(ifp, IFCOUNTER_IERRORS,
532 	    RD4(sc, FEC_RMON_R_CRC_ALIGN) + RD4(sc, FEC_RMON_R_UNDERSIZE) +
533 	    RD4(sc, FEC_RMON_R_OVERSIZE) + RD4(sc, FEC_RMON_R_FRAG) +
534 	    RD4(sc, FEC_RMON_R_JAB) + RD4(sc, FEC_IEEE_R_DROP));
535 
536 	if_inc_counter(ifp, IFCOUNTER_IQDROPS, RD4(sc, FEC_IEEE_R_MACERR));
537 
538 	if_inc_counter(ifp, IFCOUNTER_OPACKETS, RD4(sc, FEC_RMON_T_PACKETS));
539 	if_inc_counter(ifp, IFCOUNTER_OMCASTS, RD4(sc, FEC_RMON_T_MC_PKT));
540 	if_inc_counter(ifp, IFCOUNTER_OERRORS,
541 	    RD4(sc, FEC_RMON_T_CRC_ALIGN) + RD4(sc, FEC_RMON_T_UNDERSIZE) +
542 	    RD4(sc, FEC_RMON_T_OVERSIZE) + RD4(sc, FEC_RMON_T_FRAG) +
543 	    RD4(sc, FEC_RMON_T_JAB));
544 
545 	if_inc_counter(ifp, IFCOUNTER_COLLISIONS, RD4(sc, FEC_RMON_T_COL));
546 
547 	ffec_clear_stats(sc);
548 }
549 
550 static void
551 ffec_tick(void *arg)
552 {
553 	struct ffec_softc *sc;
554 	if_t ifp;
555 	int link_was_up;
556 
557 	sc = arg;
558 
559 	FFEC_ASSERT_LOCKED(sc);
560 
561 	ifp = sc->ifp;
562 
563 	if (!(if_getdrvflags(ifp) & IFF_DRV_RUNNING))
564 	    return;
565 
566 	/*
567 	 * Typical tx watchdog.  If this fires it indicates that we enqueued
568 	 * packets for output and never got a txdone interrupt for them.  Maybe
569 	 * it's a missed interrupt somehow, just pretend we got one.
570 	 */
571 	if (sc->tx_watchdog_count > 0) {
572 		if (--sc->tx_watchdog_count == 0) {
573 			ffec_txfinish_locked(sc);
574 		}
575 	}
576 
577 	/* Gather stats from hardware counters. */
578 	ffec_harvest_stats(sc);
579 
580 	/* Check the media status. */
581 	link_was_up = sc->link_is_up;
582 	mii_tick(sc->mii_softc);
583 	if (sc->link_is_up && !link_was_up)
584 		ffec_txstart_locked(sc);
585 
586 	/* Schedule another check one second from now. */
587 	callout_reset(&sc->ffec_callout, hz, ffec_tick, sc);
588 }
589 
590 inline static uint32_t
591 ffec_setup_txdesc(struct ffec_softc *sc, int idx, bus_addr_t paddr,
592     uint32_t len)
593 {
594 	uint32_t nidx;
595 	uint32_t flags;
596 
597 	nidx = next_txidx(sc, idx);
598 
599 	/* Addr/len 0 means we're clearing the descriptor after xmit done. */
600 	if (paddr == 0 || len == 0) {
601 		flags = 0;
602 		--sc->txcount;
603 	} else {
604 		flags = FEC_TXDESC_READY | FEC_TXDESC_L | FEC_TXDESC_TC;
605 		++sc->txcount;
606 	}
607 	if (nidx == 0)
608 		flags |= FEC_TXDESC_WRAP;
609 
610 	/*
611 	 * The hardware requires 32-bit physical addresses.  We set up the dma
612 	 * tag to indicate that, so the cast to uint32_t should never lose
613 	 * significant bits.
614 	 */
615 	sc->txdesc_ring[idx].buf_paddr = (uint32_t)paddr;
616 	sc->txdesc_ring[idx].flags_len = flags | len; /* Must be set last! */
617 
618 	return (nidx);
619 }
620 
621 static int
622 ffec_setup_txbuf(struct ffec_softc *sc, int idx, struct mbuf **mp)
623 {
624 	struct mbuf * m;
625 	int error, nsegs;
626 	struct bus_dma_segment seg;
627 
628 	if ((m = m_defrag(*mp, M_NOWAIT)) == NULL)
629 		return (ENOMEM);
630 	*mp = m;
631 
632 	error = bus_dmamap_load_mbuf_sg(sc->txbuf_tag, sc->txbuf_map[idx].map,
633 	    m, &seg, &nsegs, 0);
634 	if (error != 0) {
635 		return (ENOMEM);
636 	}
637 	bus_dmamap_sync(sc->txbuf_tag, sc->txbuf_map[idx].map,
638 	    BUS_DMASYNC_PREWRITE);
639 
640 	sc->txbuf_map[idx].mbuf = m;
641 	ffec_setup_txdesc(sc, idx, seg.ds_addr, seg.ds_len);
642 
643 	return (0);
644 
645 }
646 
647 static void
648 ffec_txstart_locked(struct ffec_softc *sc)
649 {
650 	if_t ifp;
651 	struct mbuf *m;
652 	int enqueued;
653 
654 	FFEC_ASSERT_LOCKED(sc);
655 
656 	if (!sc->link_is_up)
657 		return;
658 
659 	ifp = sc->ifp;
660 
661 	if (if_getdrvflags(ifp) & IFF_DRV_OACTIVE)
662 		return;
663 
664 	enqueued = 0;
665 
666 	for (;;) {
667 		if (sc->txcount == (TX_DESC_COUNT-1)) {
668 			if_setdrvflagbits(ifp, IFF_DRV_OACTIVE, 0);
669 			break;
670 		}
671 		m = if_dequeue(ifp);
672 		if (m == NULL)
673 			break;
674 		if (ffec_setup_txbuf(sc, sc->tx_idx_head, &m) != 0) {
675 			if_sendq_prepend(ifp, m);
676 			break;
677 		}
678 		BPF_MTAP(ifp, m);
679 		sc->tx_idx_head = next_txidx(sc, sc->tx_idx_head);
680 		++enqueued;
681 	}
682 
683 	if (enqueued != 0) {
684 		bus_dmamap_sync(sc->txdesc_tag, sc->txdesc_map, BUS_DMASYNC_PREWRITE);
685 		WR4(sc, FEC_TDAR_REG, FEC_TDAR_TDAR);
686 		bus_dmamap_sync(sc->txdesc_tag, sc->txdesc_map, BUS_DMASYNC_POSTWRITE);
687 		sc->tx_watchdog_count = WATCHDOG_TIMEOUT_SECS;
688 	}
689 }
690 
691 static void
692 ffec_txstart(if_t ifp)
693 {
694 	struct ffec_softc *sc = if_getsoftc(ifp);
695 
696 	FFEC_LOCK(sc);
697 	ffec_txstart_locked(sc);
698 	FFEC_UNLOCK(sc);
699 }
700 
701 static void
702 ffec_txfinish_locked(struct ffec_softc *sc)
703 {
704 	if_t ifp;
705 	struct ffec_hwdesc *desc;
706 	struct ffec_bufmap *bmap;
707 	boolean_t retired_buffer;
708 
709 	FFEC_ASSERT_LOCKED(sc);
710 
711 	/* XXX Can't set PRE|POST right now, but we need both. */
712 	bus_dmamap_sync(sc->txdesc_tag, sc->txdesc_map, BUS_DMASYNC_PREREAD);
713 	bus_dmamap_sync(sc->txdesc_tag, sc->txdesc_map, BUS_DMASYNC_POSTREAD);
714 	ifp = sc->ifp;
715 	retired_buffer = false;
716 	while (sc->tx_idx_tail != sc->tx_idx_head) {
717 		desc = &sc->txdesc_ring[sc->tx_idx_tail];
718 		if (desc->flags_len & FEC_TXDESC_READY)
719 			break;
720 		retired_buffer = true;
721 		bmap = &sc->txbuf_map[sc->tx_idx_tail];
722 		bus_dmamap_sync(sc->txbuf_tag, bmap->map,
723 		    BUS_DMASYNC_POSTWRITE);
724 		bus_dmamap_unload(sc->txbuf_tag, bmap->map);
725 		m_freem(bmap->mbuf);
726 		bmap->mbuf = NULL;
727 		ffec_setup_txdesc(sc, sc->tx_idx_tail, 0, 0);
728 		sc->tx_idx_tail = next_txidx(sc, sc->tx_idx_tail);
729 	}
730 
731 	/*
732 	 * If we retired any buffers, there will be open tx slots available in
733 	 * the descriptor ring, go try to start some new output.
734 	 */
735 	if (retired_buffer) {
736 		if_setdrvflagbits(ifp, 0, IFF_DRV_OACTIVE);
737 		ffec_txstart_locked(sc);
738 	}
739 
740 	/* If there are no buffers outstanding, muzzle the watchdog. */
741 	if (sc->tx_idx_tail == sc->tx_idx_head) {
742 		sc->tx_watchdog_count = 0;
743 	}
744 }
745 
746 inline static uint32_t
747 ffec_setup_rxdesc(struct ffec_softc *sc, int idx, bus_addr_t paddr)
748 {
749 	uint32_t nidx;
750 
751 	/*
752 	 * The hardware requires 32-bit physical addresses.  We set up the dma
753 	 * tag to indicate that, so the cast to uint32_t should never lose
754 	 * significant bits.
755 	 */
756 	nidx = next_rxidx(sc, idx);
757 	sc->rxdesc_ring[idx].buf_paddr = (uint32_t)paddr;
758 	sc->rxdesc_ring[idx].flags_len = FEC_RXDESC_EMPTY |
759 		((nidx == 0) ? FEC_RXDESC_WRAP : 0);
760 
761 	return (nidx);
762 }
763 
764 static int
765 ffec_setup_rxbuf(struct ffec_softc *sc, int idx, struct mbuf * m)
766 {
767 	int error, nsegs;
768 	struct bus_dma_segment seg;
769 
770 	if (!(sc->fecflags & FECFLAG_RACC)) {
771 		/*
772 		 * The RACC[SHIFT16] feature is not available.  So, we need to
773 		 * leave at least ETHER_ALIGN bytes free at the beginning of the
774 		 * buffer to allow the data to be re-aligned after receiving it
775 		 * (by copying it backwards ETHER_ALIGN bytes in the same
776 		 * buffer).  We also have to ensure that the beginning of the
777 		 * buffer is aligned to the hardware's requirements.
778 		 */
779 		m_adj(m, roundup(ETHER_ALIGN, sc->rxbuf_align));
780 	}
781 
782 	error = bus_dmamap_load_mbuf_sg(sc->rxbuf_tag, sc->rxbuf_map[idx].map,
783 	    m, &seg, &nsegs, 0);
784 	if (error != 0) {
785 		return (error);
786 	}
787 
788 	bus_dmamap_sync(sc->rxbuf_tag, sc->rxbuf_map[idx].map,
789 	    BUS_DMASYNC_PREREAD);
790 
791 	sc->rxbuf_map[idx].mbuf = m;
792 	ffec_setup_rxdesc(sc, idx, seg.ds_addr);
793 
794 	return (0);
795 }
796 
797 static struct mbuf *
798 ffec_alloc_mbufcl(struct ffec_softc *sc)
799 {
800 	struct mbuf *m;
801 
802 	m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
803 	if (m != NULL)
804 		m->m_pkthdr.len = m->m_len = m->m_ext.ext_size;
805 
806 	return (m);
807 }
808 
809 static void
810 ffec_rxfinish_onebuf(struct ffec_softc *sc, int len)
811 {
812 	struct mbuf *m, *newmbuf;
813 	struct ffec_bufmap *bmap;
814 	uint8_t *dst, *src;
815 	int error;
816 
817 	/*
818 	 *  First try to get a new mbuf to plug into this slot in the rx ring.
819 	 *  If that fails, drop the current packet and recycle the current
820 	 *  mbuf, which is still mapped and loaded.
821 	 */
822 	if ((newmbuf = ffec_alloc_mbufcl(sc)) == NULL) {
823 		if_inc_counter(sc->ifp, IFCOUNTER_IQDROPS, 1);
824 		ffec_setup_rxdesc(sc, sc->rx_idx,
825 		    sc->rxdesc_ring[sc->rx_idx].buf_paddr);
826 		return;
827 	}
828 
829 	FFEC_UNLOCK(sc);
830 
831 	bmap = &sc->rxbuf_map[sc->rx_idx];
832 	len -= ETHER_CRC_LEN;
833 	bus_dmamap_sync(sc->rxbuf_tag, bmap->map, BUS_DMASYNC_POSTREAD);
834 	bus_dmamap_unload(sc->rxbuf_tag, bmap->map);
835 	m = bmap->mbuf;
836 	bmap->mbuf = NULL;
837 	m->m_len = len;
838 	m->m_pkthdr.len = len;
839 	m->m_pkthdr.rcvif = sc->ifp;
840 
841 	/*
842 	 * Align the protocol headers in the receive buffer on a 32-bit
843 	 * boundary.  Newer hardware does the alignment for us.  On hardware
844 	 * that doesn't support this feature, we have to copy-align the data.
845 	 *
846 	 *  XXX for older hardware, could we speed this up by copying just the
847 	 *  protocol headers into their own small mbuf then chaining the cluster
848 	 *  to it? That way we'd only need to copy like 64 bytes or whatever the
849 	 *  biggest header is, instead of the whole 1530ish-byte frame.
850 	 */
851 	if (sc->fecflags & FECFLAG_RACC) {
852 		m->m_data = mtod(m, uint8_t *) + 2;
853 	} else {
854 		src = mtod(m, uint8_t*);
855 		dst = src - ETHER_ALIGN;
856 		bcopy(src, dst, len);
857 		m->m_data = dst;
858 	}
859 	if_input(sc->ifp, m);
860 
861 	FFEC_LOCK(sc);
862 
863 	if ((error = ffec_setup_rxbuf(sc, sc->rx_idx, newmbuf)) != 0) {
864 		device_printf(sc->dev, "ffec_setup_rxbuf error %d\n", error);
865 		/* XXX Now what?  We've got a hole in the rx ring. */
866 	}
867 
868 }
869 
870 static void
871 ffec_rxfinish_locked(struct ffec_softc *sc)
872 {
873 	struct ffec_hwdesc *desc;
874 	int len;
875 	boolean_t produced_empty_buffer;
876 
877 	FFEC_ASSERT_LOCKED(sc);
878 
879 	/* XXX Can't set PRE|POST right now, but we need both. */
880 	bus_dmamap_sync(sc->rxdesc_tag, sc->rxdesc_map, BUS_DMASYNC_PREREAD);
881 	bus_dmamap_sync(sc->rxdesc_tag, sc->rxdesc_map, BUS_DMASYNC_POSTREAD);
882 	produced_empty_buffer = false;
883 	for (;;) {
884 		desc = &sc->rxdesc_ring[sc->rx_idx];
885 		if (desc->flags_len & FEC_RXDESC_EMPTY)
886 			break;
887 		produced_empty_buffer = true;
888 		len = (desc->flags_len & FEC_RXDESC_LEN_MASK);
889 		if (len < 64) {
890 			/*
891 			 * Just recycle the descriptor and continue.           .
892 			 */
893 			ffec_setup_rxdesc(sc, sc->rx_idx,
894 			    sc->rxdesc_ring[sc->rx_idx].buf_paddr);
895 		} else if ((desc->flags_len & FEC_RXDESC_L) == 0) {
896 			/*
897 			 * The entire frame is not in this buffer.  Impossible.
898 			 * Recycle the descriptor and continue.
899 			 *
900 			 * XXX what's the right way to handle this? Probably we
901 			 * should stop/init the hardware because this should
902 			 * just really never happen when we have buffers bigger
903 			 * than the maximum frame size.
904 			 */
905 			device_printf(sc->dev,
906 			    "fec_rxfinish: received frame without LAST bit set");
907 			ffec_setup_rxdesc(sc, sc->rx_idx,
908 			    sc->rxdesc_ring[sc->rx_idx].buf_paddr);
909 		} else if (desc->flags_len & FEC_RXDESC_ERROR_BITS) {
910 			/*
911 			 *  Something went wrong with receiving the frame, we
912 			 *  don't care what (the hardware has counted the error
913 			 *  in the stats registers already), we just reuse the
914 			 *  same mbuf, which is still dma-mapped, by resetting
915 			 *  the rx descriptor.
916 			 */
917 			ffec_setup_rxdesc(sc, sc->rx_idx,
918 			    sc->rxdesc_ring[sc->rx_idx].buf_paddr);
919 		} else {
920 			/*
921 			 *  Normal case: a good frame all in one buffer.
922 			 */
923 			ffec_rxfinish_onebuf(sc, len);
924 		}
925 		sc->rx_idx = next_rxidx(sc, sc->rx_idx);
926 	}
927 
928 	if (produced_empty_buffer) {
929 		bus_dmamap_sync(sc->rxdesc_tag, sc->rxdesc_map, BUS_DMASYNC_PREWRITE);
930 		WR4(sc, FEC_RDAR_REG, FEC_RDAR_RDAR);
931 		bus_dmamap_sync(sc->rxdesc_tag, sc->rxdesc_map, BUS_DMASYNC_POSTWRITE);
932 	}
933 }
934 
935 static void
936 ffec_get_hwaddr(struct ffec_softc *sc, uint8_t *hwaddr)
937 {
938 	uint32_t palr, paur, rnd;
939 
940 	/*
941 	 * Try to recover a MAC address from the running hardware. If there's
942 	 * something non-zero there, assume the bootloader did the right thing
943 	 * and just use it.
944 	 *
945 	 * Otherwise, set the address to a convenient locally assigned address,
946 	 * 'bsd' + random 24 low-order bits.  'b' is 0x62, which has the locally
947 	 * assigned bit set, and the broadcast/multicast bit clear.
948 	 */
949 	palr = RD4(sc, FEC_PALR_REG);
950 	paur = RD4(sc, FEC_PAUR_REG) & FEC_PAUR_PADDR2_MASK;
951 	if ((palr | paur) != 0) {
952 		hwaddr[0] = palr >> 24;
953 		hwaddr[1] = palr >> 16;
954 		hwaddr[2] = palr >>  8;
955 		hwaddr[3] = palr >>  0;
956 		hwaddr[4] = paur >> 24;
957 		hwaddr[5] = paur >> 16;
958 	} else {
959 		rnd = arc4random() & 0x00ffffff;
960 		hwaddr[0] = 'b';
961 		hwaddr[1] = 's';
962 		hwaddr[2] = 'd';
963 		hwaddr[3] = rnd >> 16;
964 		hwaddr[4] = rnd >>  8;
965 		hwaddr[5] = rnd >>  0;
966 	}
967 
968 	if (bootverbose) {
969 		device_printf(sc->dev,
970 		    "MAC address %02x:%02x:%02x:%02x:%02x:%02x:\n",
971 		    hwaddr[0], hwaddr[1], hwaddr[2],
972 		    hwaddr[3], hwaddr[4], hwaddr[5]);
973 	}
974 }
975 
976 static u_int
977 ffec_hash_maddr(void *arg, struct sockaddr_dl *sdl, u_int cnt)
978 {
979 	uint64_t *ghash = arg;
980 	uint32_t crc;
981 
982 	/* 6 bits from MSB in LE CRC32 are used for hash. */
983 	crc = ether_crc32_le(LLADDR(sdl), ETHER_ADDR_LEN);
984 	*ghash |= 1LLU << (((uint8_t *)&crc)[3] >> 2);
985 
986 	return (1);
987 }
988 
989 static void
990 ffec_setup_rxfilter(struct ffec_softc *sc)
991 {
992 	if_t ifp;
993 	uint8_t *eaddr;
994 	uint64_t ghash, ihash;
995 
996 	FFEC_ASSERT_LOCKED(sc);
997 
998 	ifp = sc->ifp;
999 
1000 	/*
1001 	 * Set the multicast (group) filter hash.
1002 	 */
1003 	if ((if_getflags(ifp) & IFF_ALLMULTI))
1004 		ghash = 0xffffffffffffffffLLU;
1005 	else {
1006 		ghash = 0;
1007 		if_foreach_llmaddr(ifp, ffec_hash_maddr, &ghash);
1008 	}
1009 	WR4(sc, FEC_GAUR_REG, (uint32_t)(ghash >> 32));
1010 	WR4(sc, FEC_GALR_REG, (uint32_t)ghash);
1011 
1012 	/*
1013 	 * Set the individual address filter hash.
1014 	 *
1015 	 * XXX Is 0 the right value when promiscuous is off?  This hw feature
1016 	 * seems to support the concept of MAC address aliases, does such a
1017 	 * thing even exist?
1018 	 */
1019 	if ((if_getflags(ifp) & IFF_PROMISC))
1020 		ihash = 0xffffffffffffffffLLU;
1021 	else {
1022 		ihash = 0;
1023 	}
1024 	WR4(sc, FEC_IAUR_REG, (uint32_t)(ihash >> 32));
1025 	WR4(sc, FEC_IALR_REG, (uint32_t)ihash);
1026 
1027 	/*
1028 	 * Set the primary address.
1029 	 */
1030 	eaddr = if_getlladdr(ifp);
1031 	WR4(sc, FEC_PALR_REG, (eaddr[0] << 24) | (eaddr[1] << 16) |
1032 	    (eaddr[2] <<  8) | eaddr[3]);
1033 	WR4(sc, FEC_PAUR_REG, (eaddr[4] << 24) | (eaddr[5] << 16));
1034 }
1035 
1036 static void
1037 ffec_stop_locked(struct ffec_softc *sc)
1038 {
1039 	if_t ifp;
1040 	struct ffec_hwdesc *desc;
1041 	struct ffec_bufmap *bmap;
1042 	int idx;
1043 
1044 	FFEC_ASSERT_LOCKED(sc);
1045 
1046 	ifp = sc->ifp;
1047 	if_setdrvflagbits(ifp, 0, (IFF_DRV_RUNNING | IFF_DRV_OACTIVE));
1048 	sc->tx_watchdog_count = 0;
1049 
1050 	/*
1051 	 * Stop the hardware, mask all interrupts, and clear all current
1052 	 * interrupt status bits.
1053 	 */
1054 	WR4(sc, FEC_ECR_REG, RD4(sc, FEC_ECR_REG) & ~FEC_ECR_ETHEREN);
1055 	WR4(sc, FEC_IEM_REG, 0x00000000);
1056 	WR4(sc, FEC_IER_REG, 0xffffffff);
1057 
1058 	/*
1059 	 * Stop the media-check callout.  Do not use callout_drain() because
1060 	 * we're holding a mutex the callout acquires, and if it's currently
1061 	 * waiting to acquire it, we'd deadlock.  If it is waiting now, the
1062 	 * ffec_tick() routine will return without doing anything when it sees
1063 	 * that IFF_DRV_RUNNING is not set, so avoiding callout_drain() is safe.
1064 	 */
1065 	callout_stop(&sc->ffec_callout);
1066 
1067 	/*
1068 	 * Discard all untransmitted buffers.  Each buffer is simply freed;
1069 	 * it's as if the bits were transmitted and then lost on the wire.
1070 	 *
1071 	 * XXX Is this right?  Or should we use IFQ_DRV_PREPEND() to put them
1072 	 * back on the queue for when we get restarted later?
1073 	 */
1074 	idx = sc->tx_idx_tail;
1075 	while (idx != sc->tx_idx_head) {
1076 		desc = &sc->txdesc_ring[idx];
1077 		bmap = &sc->txbuf_map[idx];
1078 		if (desc->buf_paddr != 0) {
1079 			bus_dmamap_unload(sc->txbuf_tag, bmap->map);
1080 			m_freem(bmap->mbuf);
1081 			bmap->mbuf = NULL;
1082 			ffec_setup_txdesc(sc, idx, 0, 0);
1083 		}
1084 		idx = next_txidx(sc, idx);
1085 	}
1086 
1087 	/*
1088 	 * Discard all unprocessed receive buffers.  This amounts to just
1089 	 * pretending that nothing ever got received into them.  We reuse the
1090 	 * mbuf already mapped for each desc, simply turning the EMPTY flags
1091 	 * back on so they'll get reused when we start up again.
1092 	 */
1093 	for (idx = 0; idx < RX_DESC_COUNT; ++idx) {
1094 		desc = &sc->rxdesc_ring[idx];
1095 		ffec_setup_rxdesc(sc, idx, desc->buf_paddr);
1096 	}
1097 }
1098 
1099 static void
1100 ffec_init_locked(struct ffec_softc *sc)
1101 {
1102 	if_t ifp = sc->ifp;
1103 	uint32_t maxbuf, maxfl, regval;
1104 
1105 	FFEC_ASSERT_LOCKED(sc);
1106 
1107 	/*
1108 	 * The hardware has a limit of 0x7ff as the max frame length (see
1109 	 * comments for MRBR below), and we use mbuf clusters as receive
1110 	 * buffers, and we currently are designed to receive an entire frame
1111 	 * into a single buffer.
1112 	 *
1113 	 * We start with a MCLBYTES-sized cluster, but we have to offset into
1114 	 * the buffer by ETHER_ALIGN to make room for post-receive re-alignment,
1115 	 * and then that value has to be rounded up to the hardware's DMA
1116 	 * alignment requirements, so all in all our buffer is that much smaller
1117 	 * than MCLBYTES.
1118 	 *
1119 	 * The resulting value is used as the frame truncation length and the
1120 	 * max buffer receive buffer size for now.  It'll become more complex
1121 	 * when we support jumbo frames and receiving fragments of them into
1122 	 * separate buffers.
1123 	 */
1124 	maxbuf = MCLBYTES - roundup(ETHER_ALIGN, sc->rxbuf_align);
1125 	maxfl = min(maxbuf, 0x7ff);
1126 
1127 	if (if_getdrvflags(ifp) & IFF_DRV_RUNNING)
1128 		return;
1129 
1130 	/* Mask all interrupts and clear all current interrupt status bits. */
1131 	WR4(sc, FEC_IEM_REG, 0x00000000);
1132 	WR4(sc, FEC_IER_REG, 0xffffffff);
1133 
1134 	/*
1135 	 * Go set up palr/puar, galr/gaur, ialr/iaur.
1136 	 */
1137 	ffec_setup_rxfilter(sc);
1138 
1139 	/*
1140 	 * TFWR - Transmit FIFO watermark register.
1141 	 *
1142 	 * Set the transmit fifo watermark register to "store and forward" mode
1143 	 * and also set a threshold of 128 bytes in the fifo before transmission
1144 	 * of a frame begins (to avoid dma underruns).  Recent FEC hardware
1145 	 * supports STRFWD and when that bit is set, the watermark level in the
1146 	 * low bits is ignored.  Older hardware doesn't have STRFWD, but writing
1147 	 * to that bit is innocuous, and the TWFR bits get used instead.
1148 	 */
1149 	WR4(sc, FEC_TFWR_REG, FEC_TFWR_STRFWD | FEC_TFWR_TWFR_128BYTE);
1150 
1151 	/* RCR - Receive control register.
1152 	 *
1153 	 * Set max frame length + clean out anything left from u-boot.
1154 	 */
1155 	WR4(sc, FEC_RCR_REG, (maxfl << FEC_RCR_MAX_FL_SHIFT));
1156 
1157 	/*
1158 	 * TCR - Transmit control register.
1159 	 *
1160 	 * Clean out anything left from u-boot.  Any necessary values are set in
1161 	 * ffec_miibus_statchg() based on the media type.
1162 	 */
1163 	WR4(sc, FEC_TCR_REG, 0);
1164 
1165 	/*
1166 	 * OPD - Opcode/pause duration.
1167 	 *
1168 	 * XXX These magic numbers come from u-boot.
1169 	 */
1170 	WR4(sc, FEC_OPD_REG, 0x00010020);
1171 
1172 	/*
1173 	 * FRSR - Fifo receive start register.
1174 	 *
1175 	 * This register does not exist on imx6, it is present on earlier
1176 	 * hardware. The u-boot code sets this to a non-default value that's 32
1177 	 * bytes larger than the default, with no clue as to why.  The default
1178 	 * value should work fine, so there's no code to init it here.
1179 	 */
1180 
1181 	/*
1182 	 *  MRBR - Max RX buffer size.
1183 	 *
1184 	 *  Note: For hardware prior to imx6 this value cannot exceed 0x07ff,
1185 	 *  but the datasheet says no such thing for imx6.  On the imx6, setting
1186 	 *  this to 2K without setting EN1588 resulted in a crazy runaway
1187 	 *  receive loop in the hardware, where every rx descriptor in the ring
1188 	 *  had its EMPTY flag cleared, no completion or error flags set, and a
1189 	 *  length of zero.  I think maybe you can only exceed it when EN1588 is
1190 	 *  set, like maybe that's what enables jumbo frames, because in general
1191 	 *  the EN1588 flag seems to be the "enable new stuff" vs. "be legacy-
1192 	 *  compatible" flag.
1193 	 */
1194 	WR4(sc, FEC_MRBR_REG, maxfl << FEC_MRBR_R_BUF_SIZE_SHIFT);
1195 
1196 	/*
1197 	 * FTRL - Frame truncation length.
1198 	 *
1199 	 * Must be greater than or equal to the value set in FEC_RCR_MAXFL.
1200 	 */
1201 	WR4(sc, FEC_FTRL_REG, maxfl);
1202 
1203 	/*
1204 	 * RDSR / TDSR descriptor ring pointers.
1205 	 *
1206 	 * When we turn on ECR_ETHEREN at the end, the hardware zeroes its
1207 	 * internal current descriptor index values for both rings, so we zero
1208 	 * our index values as well.
1209 	 */
1210 	sc->rx_idx = 0;
1211 	sc->tx_idx_head = sc->tx_idx_tail = 0;
1212 	sc->txcount = 0;
1213 	WR4(sc, FEC_RDSR_REG, sc->rxdesc_ring_paddr);
1214 	WR4(sc, FEC_TDSR_REG, sc->txdesc_ring_paddr);
1215 
1216 	/*
1217 	 * EIM - interrupt mask register.
1218 	 *
1219 	 * We always enable the same set of interrupts while running; unlike
1220 	 * some drivers there's no need to change the mask on the fly depending
1221 	 * on what operations are in progress.
1222 	 */
1223 	WR4(sc, FEC_IEM_REG, FEC_IER_TXF | FEC_IER_RXF | FEC_IER_EBERR);
1224 
1225 	/*
1226 	 * MIBC - MIB control (hardware stats); clear all statistics regs, then
1227 	 * enable collection of statistics.
1228 	 */
1229 	regval = RD4(sc, FEC_MIBC_REG);
1230 	WR4(sc, FEC_MIBC_REG, regval | FEC_MIBC_DIS);
1231 	ffec_clear_stats(sc);
1232 	WR4(sc, FEC_MIBC_REG, regval & ~FEC_MIBC_DIS);
1233 
1234 	if (sc->fecflags & FECFLAG_RACC) {
1235 		/*
1236 		 * RACC - Receive Accelerator Function Configuration.
1237 		 */
1238 		regval = RD4(sc, FEC_RACC_REG);
1239 		WR4(sc, FEC_RACC_REG, regval | FEC_RACC_SHIFT16);
1240 	}
1241 
1242 	/*
1243 	 * ECR - Ethernet control register.
1244 	 *
1245 	 * This must happen after all the other config registers are set.  If
1246 	 * we're running on little-endian hardware, also set the flag for byte-
1247 	 * swapping descriptor ring entries.  This flag doesn't exist on older
1248 	 * hardware, but it can be safely set -- the bit position it occupies
1249 	 * was unused.
1250 	 */
1251 	regval = RD4(sc, FEC_ECR_REG);
1252 #if _BYTE_ORDER == _LITTLE_ENDIAN
1253 	regval |= FEC_ECR_DBSWP;
1254 #endif
1255 	regval |= FEC_ECR_ETHEREN;
1256 	WR4(sc, FEC_ECR_REG, regval);
1257 
1258 	if_setdrvflagbits(ifp, IFF_DRV_RUNNING, 0);
1259 
1260        /*
1261 	* Call mii_mediachg() which will call back into ffec_miibus_statchg() to
1262 	* set up the remaining config registers based on the current media.
1263 	*/
1264 	mii_mediachg(sc->mii_softc);
1265 	callout_reset(&sc->ffec_callout, hz, ffec_tick, sc);
1266 
1267 	/*
1268 	 * Tell the hardware that receive buffers are available.  They were made
1269 	 * available in ffec_attach() or ffec_stop().
1270 	 */
1271 	WR4(sc, FEC_RDAR_REG, FEC_RDAR_RDAR);
1272 }
1273 
1274 static void
1275 ffec_init(void *if_softc)
1276 {
1277 	struct ffec_softc *sc = if_softc;
1278 
1279 	FFEC_LOCK(sc);
1280 	ffec_init_locked(sc);
1281 	FFEC_UNLOCK(sc);
1282 }
1283 
1284 static void
1285 ffec_intr(void *arg)
1286 {
1287 	struct ffec_softc *sc;
1288 	uint32_t ier;
1289 
1290 	sc = arg;
1291 
1292 	FFEC_LOCK(sc);
1293 
1294 	ier = RD4(sc, FEC_IER_REG);
1295 
1296 	if (ier & FEC_IER_TXF) {
1297 		WR4(sc, FEC_IER_REG, FEC_IER_TXF);
1298 		ffec_txfinish_locked(sc);
1299 	}
1300 
1301 	if (ier & FEC_IER_RXF) {
1302 		WR4(sc, FEC_IER_REG, FEC_IER_RXF);
1303 		ffec_rxfinish_locked(sc);
1304 	}
1305 
1306 	/*
1307 	 * We actually don't care about most errors, because the hardware copes
1308 	 * with them just fine, discarding the incoming bad frame, or forcing a
1309 	 * bad CRC onto an outgoing bad frame, and counting the errors in the
1310 	 * stats registers.  The one that really matters is EBERR (DMA bus
1311 	 * error) because the hardware automatically clears ECR[ETHEREN] and we
1312 	 * have to restart it here.  It should never happen.
1313 	 */
1314 	if (ier & FEC_IER_EBERR) {
1315 		WR4(sc, FEC_IER_REG, FEC_IER_EBERR);
1316 		device_printf(sc->dev,
1317 		    "Ethernet DMA error, restarting controller.\n");
1318 		ffec_stop_locked(sc);
1319 		ffec_init_locked(sc);
1320 	}
1321 
1322 	FFEC_UNLOCK(sc);
1323 
1324 }
1325 
1326 static int
1327 ffec_ioctl(if_t ifp, u_long cmd, caddr_t data)
1328 {
1329 	struct ffec_softc *sc;
1330 	struct mii_data *mii;
1331 	struct ifreq *ifr;
1332 	int mask, error;
1333 
1334 	sc = if_getsoftc(ifp);
1335 	ifr = (struct ifreq *)data;
1336 
1337 	error = 0;
1338 	switch (cmd) {
1339 	case SIOCSIFFLAGS:
1340 		FFEC_LOCK(sc);
1341 		if (if_getflags(ifp) & IFF_UP) {
1342 			if (if_getdrvflags(ifp) & IFF_DRV_RUNNING) {
1343 				if ((if_getflags(ifp) ^ sc->if_flags) &
1344 				    (IFF_PROMISC | IFF_ALLMULTI))
1345 					ffec_setup_rxfilter(sc);
1346 			} else {
1347 				if (!sc->is_detaching)
1348 					ffec_init_locked(sc);
1349 			}
1350 		} else {
1351 			if (if_getdrvflags(ifp) & IFF_DRV_RUNNING)
1352 				ffec_stop_locked(sc);
1353 		}
1354 		sc->if_flags = if_getflags(ifp);
1355 		FFEC_UNLOCK(sc);
1356 		break;
1357 
1358 	case SIOCADDMULTI:
1359 	case SIOCDELMULTI:
1360 		if (if_getdrvflags(ifp) & IFF_DRV_RUNNING) {
1361 			FFEC_LOCK(sc);
1362 			ffec_setup_rxfilter(sc);
1363 			FFEC_UNLOCK(sc);
1364 		}
1365 		break;
1366 
1367 	case SIOCSIFMEDIA:
1368 	case SIOCGIFMEDIA:
1369 		mii = sc->mii_softc;
1370 		error = ifmedia_ioctl(ifp, ifr, &mii->mii_media, cmd);
1371 		break;
1372 
1373 	case SIOCSIFCAP:
1374 		mask = if_getcapenable(ifp) ^ ifr->ifr_reqcap;
1375 		if (mask & IFCAP_VLAN_MTU) {
1376 			/* No work to do except acknowledge the change took. */
1377 			if_togglecapenable(ifp, IFCAP_VLAN_MTU);
1378 		}
1379 		break;
1380 
1381 	default:
1382 		error = ether_ioctl(ifp, cmd, data);
1383 		break;
1384 	}
1385 
1386 	return (error);
1387 }
1388 
1389 static int
1390 ffec_detach(device_t dev)
1391 {
1392 	struct ffec_softc *sc;
1393 	bus_dmamap_t map;
1394 	int idx, irq;
1395 
1396 	/*
1397 	 * NB: This function can be called internally to unwind a failure to
1398 	 * attach. Make sure a resource got allocated/created before destroying.
1399 	 */
1400 
1401 	sc = device_get_softc(dev);
1402 
1403 	if (sc->is_attached) {
1404 		FFEC_LOCK(sc);
1405 		sc->is_detaching = true;
1406 		ffec_stop_locked(sc);
1407 		FFEC_UNLOCK(sc);
1408 		callout_drain(&sc->ffec_callout);
1409 		ether_ifdetach(sc->ifp);
1410 	}
1411 
1412 	/* XXX no miibus detach? */
1413 
1414 	/* Clean up RX DMA resources and free mbufs. */
1415 	for (idx = 0; idx < RX_DESC_COUNT; ++idx) {
1416 		if ((map = sc->rxbuf_map[idx].map) != NULL) {
1417 			bus_dmamap_unload(sc->rxbuf_tag, map);
1418 			bus_dmamap_destroy(sc->rxbuf_tag, map);
1419 			m_freem(sc->rxbuf_map[idx].mbuf);
1420 		}
1421 	}
1422 	if (sc->rxbuf_tag != NULL)
1423 		bus_dma_tag_destroy(sc->rxbuf_tag);
1424 	if (sc->rxdesc_map != NULL) {
1425 		bus_dmamap_unload(sc->rxdesc_tag, sc->rxdesc_map);
1426 		bus_dmamem_free(sc->rxdesc_tag, sc->rxdesc_ring,
1427 		    sc->rxdesc_map);
1428 	}
1429 	if (sc->rxdesc_tag != NULL)
1430 		bus_dma_tag_destroy(sc->rxdesc_tag);
1431 
1432 	/* Clean up TX DMA resources. */
1433 	for (idx = 0; idx < TX_DESC_COUNT; ++idx) {
1434 		if ((map = sc->txbuf_map[idx].map) != NULL) {
1435 			/* TX maps are already unloaded. */
1436 			bus_dmamap_destroy(sc->txbuf_tag, map);
1437 		}
1438 	}
1439 	if (sc->txbuf_tag != NULL)
1440 		bus_dma_tag_destroy(sc->txbuf_tag);
1441 	if (sc->txdesc_map != NULL) {
1442 		bus_dmamap_unload(sc->txdesc_tag, sc->txdesc_map);
1443 		bus_dmamem_free(sc->txdesc_tag, sc->txdesc_ring,
1444 		    sc->txdesc_map);
1445 	}
1446 	if (sc->txdesc_tag != NULL)
1447 		bus_dma_tag_destroy(sc->txdesc_tag);
1448 
1449 	/* Release bus resources. */
1450 	for (irq = 0; irq < MAX_IRQ_COUNT; ++irq) {
1451 		if (sc->intr_cookie[irq] != NULL) {
1452 			bus_teardown_intr(dev, sc->irq_res[irq],
1453 			    sc->intr_cookie[irq]);
1454 		}
1455 	}
1456 	bus_release_resources(dev, irq_res_spec, sc->irq_res);
1457 
1458 	if (sc->mem_res != NULL)
1459 		bus_release_resource(dev, SYS_RES_MEMORY, 0, sc->mem_res);
1460 
1461 	FFEC_LOCK_DESTROY(sc);
1462 	return (0);
1463 }
1464 
1465 static int
1466 ffec_attach(device_t dev)
1467 {
1468 	struct ffec_softc *sc;
1469 	if_t ifp = NULL;
1470 	struct mbuf *m;
1471 	void *dummy;
1472 	uintptr_t typeflags;
1473 	phandle_t ofw_node;
1474 	uint32_t idx, mscr;
1475 	int error, phynum, rid, irq;
1476 	uint8_t eaddr[ETHER_ADDR_LEN];
1477 
1478 	sc = device_get_softc(dev);
1479 	sc->dev = dev;
1480 
1481 	FFEC_LOCK_INIT(sc);
1482 
1483 	/*
1484 	 * There are differences in the implementation and features of the FEC
1485 	 * hardware on different SoCs, so figure out what type we are.
1486 	 */
1487 	typeflags = ofw_bus_search_compatible(dev, compat_data)->ocd_data;
1488 	sc->fectype = (uint8_t)(typeflags & FECTYPE_MASK);
1489 	sc->fecflags = (uint32_t)(typeflags & ~FECTYPE_MASK);
1490 
1491 	if (sc->fecflags & FECFLAG_AVB) {
1492 		sc->rxbuf_align = 64;
1493 		sc->txbuf_align = 1;
1494 	} else {
1495 		sc->rxbuf_align = 16;
1496 		sc->txbuf_align = 16;
1497 	}
1498 
1499 	/*
1500 	 * We have to be told what kind of electrical connection exists between
1501 	 * the MAC and PHY or we can't operate correctly.
1502 	 */
1503 	if ((ofw_node = ofw_bus_get_node(dev)) == -1) {
1504 		device_printf(dev, "Impossible: Can't find ofw bus node\n");
1505 		error = ENXIO;
1506 		goto out;
1507 	}
1508 	sc->phy_conn_type = mii_fdt_get_contype(ofw_node);
1509 	if (sc->phy_conn_type == MII_CONTYPE_UNKNOWN) {
1510 		device_printf(sc->dev, "No valid 'phy-mode' "
1511 		    "property found in FDT data for device.\n");
1512 		error = ENOATTR;
1513 		goto out;
1514 	}
1515 
1516 	callout_init_mtx(&sc->ffec_callout, &sc->mtx, 0);
1517 
1518 	/* Allocate bus resources for accessing the hardware. */
1519 	rid = 0;
1520 	sc->mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid,
1521 	    RF_ACTIVE);
1522 	if (sc->mem_res == NULL) {
1523 		device_printf(dev, "could not allocate memory resources.\n");
1524 		error = ENOMEM;
1525 		goto out;
1526 	}
1527 
1528 	error = bus_alloc_resources(dev, irq_res_spec, sc->irq_res);
1529 	if (error != 0) {
1530 		device_printf(dev, "could not allocate interrupt resources\n");
1531 		goto out;
1532 	}
1533 
1534 	/*
1535 	 * Set up TX descriptor ring, descriptors, and dma maps.
1536 	 */
1537 	error = bus_dma_tag_create(
1538 	    bus_get_dma_tag(dev),	/* Parent tag. */
1539 	    FEC_DESC_RING_ALIGN, 0,	/* alignment, boundary */
1540 	    BUS_SPACE_MAXADDR_32BIT,	/* lowaddr */
1541 	    BUS_SPACE_MAXADDR,		/* highaddr */
1542 	    NULL, NULL,			/* filter, filterarg */
1543 	    TX_DESC_SIZE, 1, 		/* maxsize, nsegments */
1544 	    TX_DESC_SIZE,		/* maxsegsize */
1545 	    0,				/* flags */
1546 	    NULL, NULL,			/* lockfunc, lockarg */
1547 	    &sc->txdesc_tag);
1548 	if (error != 0) {
1549 		device_printf(sc->dev,
1550 		    "could not create TX ring DMA tag.\n");
1551 		goto out;
1552 	}
1553 
1554 	error = bus_dmamem_alloc(sc->txdesc_tag, (void**)&sc->txdesc_ring,
1555 	    BUS_DMA_COHERENT | BUS_DMA_WAITOK | BUS_DMA_ZERO, &sc->txdesc_map);
1556 	if (error != 0) {
1557 		device_printf(sc->dev,
1558 		    "could not allocate TX descriptor ring.\n");
1559 		goto out;
1560 	}
1561 
1562 	error = bus_dmamap_load(sc->txdesc_tag, sc->txdesc_map, sc->txdesc_ring,
1563 	    TX_DESC_SIZE, ffec_get1paddr, &sc->txdesc_ring_paddr, 0);
1564 	if (error != 0) {
1565 		device_printf(sc->dev,
1566 		    "could not load TX descriptor ring map.\n");
1567 		goto out;
1568 	}
1569 
1570 	error = bus_dma_tag_create(
1571 	    bus_get_dma_tag(dev),	/* Parent tag. */
1572 	    sc->txbuf_align, 0,		/* alignment, boundary */
1573 	    BUS_SPACE_MAXADDR_32BIT,	/* lowaddr */
1574 	    BUS_SPACE_MAXADDR,		/* highaddr */
1575 	    NULL, NULL,			/* filter, filterarg */
1576 	    MCLBYTES, 1, 		/* maxsize, nsegments */
1577 	    MCLBYTES,			/* maxsegsize */
1578 	    0,				/* flags */
1579 	    NULL, NULL,			/* lockfunc, lockarg */
1580 	    &sc->txbuf_tag);
1581 	if (error != 0) {
1582 		device_printf(sc->dev,
1583 		    "could not create TX ring DMA tag.\n");
1584 		goto out;
1585 	}
1586 
1587 	for (idx = 0; idx < TX_DESC_COUNT; ++idx) {
1588 		error = bus_dmamap_create(sc->txbuf_tag, 0,
1589 		    &sc->txbuf_map[idx].map);
1590 		if (error != 0) {
1591 			device_printf(sc->dev,
1592 			    "could not create TX buffer DMA map.\n");
1593 			goto out;
1594 		}
1595 		ffec_setup_txdesc(sc, idx, 0, 0);
1596 	}
1597 
1598 	/*
1599 	 * Set up RX descriptor ring, descriptors, dma maps, and mbufs.
1600 	 */
1601 	error = bus_dma_tag_create(
1602 	    bus_get_dma_tag(dev),	/* Parent tag. */
1603 	    FEC_DESC_RING_ALIGN, 0,	/* alignment, boundary */
1604 	    BUS_SPACE_MAXADDR_32BIT,	/* lowaddr */
1605 	    BUS_SPACE_MAXADDR,		/* highaddr */
1606 	    NULL, NULL,			/* filter, filterarg */
1607 	    RX_DESC_SIZE, 1, 		/* maxsize, nsegments */
1608 	    RX_DESC_SIZE,		/* maxsegsize */
1609 	    0,				/* flags */
1610 	    NULL, NULL,			/* lockfunc, lockarg */
1611 	    &sc->rxdesc_tag);
1612 	if (error != 0) {
1613 		device_printf(sc->dev,
1614 		    "could not create RX ring DMA tag.\n");
1615 		goto out;
1616 	}
1617 
1618 	error = bus_dmamem_alloc(sc->rxdesc_tag, (void **)&sc->rxdesc_ring,
1619 	    BUS_DMA_COHERENT | BUS_DMA_WAITOK | BUS_DMA_ZERO, &sc->rxdesc_map);
1620 	if (error != 0) {
1621 		device_printf(sc->dev,
1622 		    "could not allocate RX descriptor ring.\n");
1623 		goto out;
1624 	}
1625 
1626 	error = bus_dmamap_load(sc->rxdesc_tag, sc->rxdesc_map, sc->rxdesc_ring,
1627 	    RX_DESC_SIZE, ffec_get1paddr, &sc->rxdesc_ring_paddr, 0);
1628 	if (error != 0) {
1629 		device_printf(sc->dev,
1630 		    "could not load RX descriptor ring map.\n");
1631 		goto out;
1632 	}
1633 
1634 	error = bus_dma_tag_create(
1635 	    bus_get_dma_tag(dev),	/* Parent tag. */
1636 	    1, 0,			/* alignment, boundary */
1637 	    BUS_SPACE_MAXADDR_32BIT,	/* lowaddr */
1638 	    BUS_SPACE_MAXADDR,		/* highaddr */
1639 	    NULL, NULL,			/* filter, filterarg */
1640 	    MCLBYTES, 1, 		/* maxsize, nsegments */
1641 	    MCLBYTES,			/* maxsegsize */
1642 	    0,				/* flags */
1643 	    NULL, NULL,			/* lockfunc, lockarg */
1644 	    &sc->rxbuf_tag);
1645 	if (error != 0) {
1646 		device_printf(sc->dev,
1647 		    "could not create RX buf DMA tag.\n");
1648 		goto out;
1649 	}
1650 
1651 	for (idx = 0; idx < RX_DESC_COUNT; ++idx) {
1652 		error = bus_dmamap_create(sc->rxbuf_tag, 0,
1653 		    &sc->rxbuf_map[idx].map);
1654 		if (error != 0) {
1655 			device_printf(sc->dev,
1656 			    "could not create RX buffer DMA map.\n");
1657 			goto out;
1658 		}
1659 		if ((m = ffec_alloc_mbufcl(sc)) == NULL) {
1660 			device_printf(dev, "Could not alloc mbuf\n");
1661 			error = ENOMEM;
1662 			goto out;
1663 		}
1664 		if ((error = ffec_setup_rxbuf(sc, idx, m)) != 0) {
1665 			device_printf(sc->dev,
1666 			    "could not create new RX buffer.\n");
1667 			goto out;
1668 		}
1669 	}
1670 
1671 	/* Try to get the MAC address from the hardware before resetting it. */
1672 	ffec_get_hwaddr(sc, eaddr);
1673 
1674 	/*
1675 	 * Reset the hardware.  Disables all interrupts.
1676 	 *
1677 	 * When the FEC is connected to the AXI bus (indicated by AVB flag), a
1678 	 * MAC reset while a bus transaction is pending can hang the bus.
1679 	 * Instead of resetting, turn off the ENABLE bit, which allows the
1680 	 * hardware to complete any in-progress transfers (appending a bad CRC
1681 	 * to any partial packet) and release the AXI bus.  This could probably
1682 	 * be done unconditionally for all hardware variants, but that hasn't
1683 	 * been tested.
1684 	 */
1685 	if (sc->fecflags & FECFLAG_AVB)
1686 		WR4(sc, FEC_ECR_REG, 0);
1687 	else
1688 		WR4(sc, FEC_ECR_REG, FEC_ECR_RESET);
1689 
1690 	/* Setup interrupt handler. */
1691 	for (irq = 0; irq < MAX_IRQ_COUNT; ++irq) {
1692 		if (sc->irq_res[irq] != NULL) {
1693 			error = bus_setup_intr(dev, sc->irq_res[irq],
1694 			    INTR_TYPE_NET | INTR_MPSAFE, NULL, ffec_intr, sc,
1695 			    &sc->intr_cookie[irq]);
1696 			if (error != 0) {
1697 				device_printf(dev,
1698 				    "could not setup interrupt handler.\n");
1699 				goto out;
1700 			}
1701 		}
1702 	}
1703 
1704 	/*
1705 	 * Set up the PHY control register.
1706 	 *
1707 	 * Speed formula for ENET is md_clock = mac_clock / ((N + 1) * 2).
1708 	 * Speed formula for FEC is  md_clock = mac_clock / (N * 2)
1709 	 *
1710 	 * XXX - Revisit this...
1711 	 *
1712 	 * For a Wandboard imx6 (ENET) I was originally using 4, but the uboot
1713 	 * code uses 10.  Both values seem to work, but I suspect many modern
1714 	 * PHY parts can do mdio at speeds far above the standard 2.5 MHz.
1715 	 *
1716 	 * Different imx manuals use confusingly different terminology (things
1717 	 * like "system clock" and "internal module clock") with examples that
1718 	 * use frequencies that have nothing to do with ethernet, giving the
1719 	 * vague impression that maybe the clock in question is the periphclock
1720 	 * or something.  In fact, on an imx53 development board (FEC),
1721 	 * measuring the mdio clock at the pin on the PHY and playing with
1722 	 * various divisors showed that the root speed was 66 MHz (clk_ipg_root
1723 	 * aka periphclock) and 13 was the right divisor.
1724 	 *
1725 	 * All in all, it seems likely that 13 is a safe divisor for now,
1726 	 * because if we really do need to base it on the peripheral clock
1727 	 * speed, then we need a platform-independent get-clock-freq API.
1728 	 */
1729 	mscr = 13 << FEC_MSCR_MII_SPEED_SHIFT;
1730 	if (OF_hasprop(ofw_node, "phy-disable-preamble")) {
1731 		mscr |= FEC_MSCR_DIS_PRE;
1732 		if (bootverbose)
1733 			device_printf(dev, "PHY preamble disabled\n");
1734 	}
1735 	WR4(sc, FEC_MSCR_REG, mscr);
1736 
1737 	/* Set up the ethernet interface. */
1738 	sc->ifp = ifp = if_alloc(IFT_ETHER);
1739 
1740 	if_setsoftc(ifp, sc);
1741 	if_initname(ifp, device_get_name(dev), device_get_unit(dev));
1742 	if_setflags(ifp, IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST);
1743 	if_setcapabilities(ifp, IFCAP_VLAN_MTU);
1744 	if_setcapenable(ifp, if_getcapabilities(ifp));
1745 	if_setstartfn(ifp, ffec_txstart);
1746 	if_setioctlfn(ifp, ffec_ioctl);
1747 	if_setinitfn(ifp, ffec_init);
1748 	if_setsendqlen(ifp, TX_DESC_COUNT - 1);
1749 	if_setsendqready(ifp);
1750 	if_setifheaderlen(ifp, sizeof(struct ether_vlan_header));
1751 
1752 #if 0 /* XXX The hardware keeps stats we could use for these. */
1753 	if_setlinkmib(ifp, &sc->mibdata);
1754 	if_setlinkmiblen(ifp, sizeof(sc->mibdata));
1755 #endif
1756 
1757 	/* Set up the miigasket hardware (if any). */
1758 	ffec_miigasket_setup(sc);
1759 
1760 	/* Attach the mii driver. */
1761 	if (fdt_get_phyaddr(ofw_node, dev, &phynum, &dummy) != 0) {
1762 		phynum = MII_PHY_ANY;
1763 	}
1764 	error = mii_attach(dev, &sc->miibus, ifp, ffec_media_change,
1765 	    ffec_media_status, BMSR_DEFCAPMASK, phynum, MII_OFFSET_ANY,
1766 	    (sc->fecflags & FECTYPE_MVF) ? MIIF_FORCEANEG : 0);
1767 	if (error != 0) {
1768 		device_printf(dev, "PHY attach failed\n");
1769 		goto out;
1770 	}
1771 	sc->mii_softc = device_get_softc(sc->miibus);
1772 
1773 	/* All ready to run, attach the ethernet interface. */
1774 	ether_ifattach(ifp, eaddr);
1775 	sc->is_attached = true;
1776 
1777 	error = 0;
1778 out:
1779 
1780 	if (error != 0)
1781 		ffec_detach(dev);
1782 
1783 	return (error);
1784 }
1785 
1786 static int
1787 ffec_probe(device_t dev)
1788 {
1789 	uintptr_t fectype;
1790 
1791 	if (!ofw_bus_status_okay(dev))
1792 		return (ENXIO);
1793 
1794 	fectype = ofw_bus_search_compatible(dev, compat_data)->ocd_data;
1795 	if (fectype == FECTYPE_NONE)
1796 		return (ENXIO);
1797 
1798 	device_set_desc(dev, (fectype & FECFLAG_GBE) ?
1799 	    "Freescale Gigabit Ethernet Controller" :
1800 	    "Freescale Fast Ethernet Controller");
1801 
1802 	return (BUS_PROBE_DEFAULT);
1803 }
1804 
1805 
1806 static device_method_t ffec_methods[] = {
1807 	/* Device interface. */
1808 	DEVMETHOD(device_probe,		ffec_probe),
1809 	DEVMETHOD(device_attach,	ffec_attach),
1810 	DEVMETHOD(device_detach,	ffec_detach),
1811 
1812 /*
1813 	DEVMETHOD(device_shutdown,	ffec_shutdown),
1814 	DEVMETHOD(device_suspend,	ffec_suspend),
1815 	DEVMETHOD(device_resume,	ffec_resume),
1816 */
1817 
1818 	/* MII interface. */
1819 	DEVMETHOD(miibus_readreg,	ffec_miibus_readreg),
1820 	DEVMETHOD(miibus_writereg,	ffec_miibus_writereg),
1821 	DEVMETHOD(miibus_statchg,	ffec_miibus_statchg),
1822 
1823 	DEVMETHOD_END
1824 };
1825 
1826 static driver_t ffec_driver = {
1827 	"ffec",
1828 	ffec_methods,
1829 	sizeof(struct ffec_softc)
1830 };
1831 
1832 DRIVER_MODULE(ffec, simplebus, ffec_driver, 0, 0);
1833 DRIVER_MODULE(miibus, ffec, miibus_driver, 0, 0);
1834 
1835 MODULE_DEPEND(ffec, ether, 1, 1, 1);
1836 MODULE_DEPEND(ffec, miibus, 1, 1, 1);
1837