xref: /netbsd-src/sys/arch/powerpc/ibm4xx/dev/if_emac.c (revision a536ee5124e62c9a0051a252f7833dc8f50f44c9)
1 /*	$NetBSD: if_emac.c,v 1.41 2012/07/22 14:32:52 matt Exp $	*/
2 
3 /*
4  * Copyright 2001, 2002 Wasabi Systems, Inc.
5  * All rights reserved.
6  *
7  * Written by Simon Burge and Jason Thorpe for Wasabi Systems, Inc.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 3. All advertising materials mentioning features or use of this software
18  *    must display the following acknowledgement:
19  *      This product includes software developed for the NetBSD Project by
20  *      Wasabi Systems, Inc.
21  * 4. The name of Wasabi Systems, Inc. may not be used to endorse
22  *    or promote products derived from this software without specific prior
23  *    written permission.
24  *
25  * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
27  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
28  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL WASABI SYSTEMS, INC
29  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
30  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
31  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
32  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
33  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
34  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
35  * POSSIBILITY OF SUCH DAMAGE.
36  */
37 
38 /*
39  * emac(4) supports following ibm4xx's EMACs.
40  *   XXXX: ZMII and 'TCP Accelaration Hardware' not support yet...
41  *
42  *            tested
43  *            ------
44  * 405EP	-  10/100 x2
45  * 405EX/EXr	o  10/100/1000 x2 (EXr x1), STA v2, 256bit hash-Table, RGMII
46  * 405GP/GPr	o  10/100
47  * 440EP	-  10/100 x2, ZMII
48  * 440GP	-  10/100 x2, ZMII
49  * 440GX	-  10/100/1000 x4, ZMII/RGMII(ch 2, 3), TAH(ch 2, 3)
50  * 440SP	-  10/100/1000
51  * 440SPe	-  10/100/1000, STA v2
52  */
53 
54 #include <sys/cdefs.h>
55 __KERNEL_RCSID(0, "$NetBSD: if_emac.c,v 1.41 2012/07/22 14:32:52 matt Exp $");
56 
57 #include "opt_emac.h"
58 
59 #include <sys/param.h>
60 #include <sys/systm.h>
61 #include <sys/mbuf.h>
62 #include <sys/kernel.h>
63 #include <sys/socket.h>
64 #include <sys/ioctl.h>
65 #include <sys/cpu.h>
66 #include <sys/device.h>
67 
68 #include <uvm/uvm_extern.h>		/* for PAGE_SIZE */
69 
70 #include <net/if.h>
71 #include <net/if_dl.h>
72 #include <net/if_media.h>
73 #include <net/if_ether.h>
74 
75 #include <net/bpf.h>
76 
77 #include <powerpc/ibm4xx/cpu.h>
78 #include <powerpc/ibm4xx/dcr4xx.h>
79 #include <powerpc/ibm4xx/mal405gp.h>
80 #include <powerpc/ibm4xx/dev/emacreg.h>
81 #include <powerpc/ibm4xx/dev/if_emacreg.h>
82 #include <powerpc/ibm4xx/dev/if_emacvar.h>
83 #include <powerpc/ibm4xx/dev/malvar.h>
84 #include <powerpc/ibm4xx/dev/opbreg.h>
85 #include <powerpc/ibm4xx/dev/opbvar.h>
86 #include <powerpc/ibm4xx/dev/plbvar.h>
87 #if defined(EMAC_ZMII_PHY) || defined(EMAC_RGMII_PHY)
88 #include <powerpc/ibm4xx/dev/rmiivar.h>
89 #endif
90 
91 #include <dev/mii/miivar.h>
92 
93 #include "locators.h"
94 
95 
96 /*
97  * Transmit descriptor list size.  There are two Tx channels, each with
98  * up to 256 hardware descriptors available.  We currently use one Tx
99  * channel.  We tell the upper layers that they can queue a lot of
100  * packets, and we go ahead and manage up to 64 of them at a time.  We
101  * allow up to 16 DMA segments per packet.
102  */
103 #define	EMAC_NTXSEGS		16
104 #define	EMAC_TXQUEUELEN		64
105 #define	EMAC_TXQUEUELEN_MASK	(EMAC_TXQUEUELEN - 1)
106 #define	EMAC_TXQUEUE_GC		(EMAC_TXQUEUELEN / 4)
107 #define	EMAC_NTXDESC		256
108 #define	EMAC_NTXDESC_MASK	(EMAC_NTXDESC - 1)
109 #define	EMAC_NEXTTX(x)		(((x) + 1) & EMAC_NTXDESC_MASK)
110 #define	EMAC_NEXTTXS(x)		(((x) + 1) & EMAC_TXQUEUELEN_MASK)
111 
112 /*
113  * Receive descriptor list size.  There is one Rx channel with up to 256
114  * hardware descriptors available.  We allocate 64 receive descriptors,
115  * each with a 2k buffer (MCLBYTES).
116  */
117 #define	EMAC_NRXDESC		64
118 #define	EMAC_NRXDESC_MASK	(EMAC_NRXDESC - 1)
119 #define	EMAC_NEXTRX(x)		(((x) + 1) & EMAC_NRXDESC_MASK)
120 #define	EMAC_PREVRX(x)		(((x) - 1) & EMAC_NRXDESC_MASK)
121 
122 /*
123  * Transmit/receive descriptors that are DMA'd to the EMAC.
124  */
125 struct emac_control_data {
126 	struct mal_descriptor ecd_txdesc[EMAC_NTXDESC];
127 	struct mal_descriptor ecd_rxdesc[EMAC_NRXDESC];
128 };
129 
130 #define	EMAC_CDOFF(x)		offsetof(struct emac_control_data, x)
131 #define	EMAC_CDTXOFF(x)		EMAC_CDOFF(ecd_txdesc[(x)])
132 #define	EMAC_CDRXOFF(x)		EMAC_CDOFF(ecd_rxdesc[(x)])
133 
134 /*
135  * Software state for transmit jobs.
136  */
137 struct emac_txsoft {
138 	struct mbuf *txs_mbuf;		/* head of mbuf chain */
139 	bus_dmamap_t txs_dmamap;	/* our DMA map */
140 	int txs_firstdesc;		/* first descriptor in packet */
141 	int txs_lastdesc;		/* last descriptor in packet */
142 	int txs_ndesc;			/* # of descriptors used */
143 };
144 
145 /*
146  * Software state for receive descriptors.
147  */
148 struct emac_rxsoft {
149 	struct mbuf *rxs_mbuf;		/* head of mbuf chain */
150 	bus_dmamap_t rxs_dmamap;	/* our DMA map */
151 };
152 
153 /*
154  * Software state per device.
155  */
156 struct emac_softc {
157 	device_t sc_dev;		/* generic device information */
158 	int sc_instance;		/* instance no. */
159 	bus_space_tag_t sc_st;		/* bus space tag */
160 	bus_space_handle_t sc_sh;	/* bus space handle */
161 	bus_dma_tag_t sc_dmat;		/* bus DMA tag */
162 	struct ethercom sc_ethercom;	/* ethernet common data */
163 	void *sc_sdhook;		/* shutdown hook */
164 	void *sc_powerhook;		/* power management hook */
165 
166 	struct mii_data sc_mii;		/* MII/media information */
167 	struct callout sc_callout;	/* tick callout */
168 
169 	uint32_t sc_mr1;		/* copy of Mode Register 1 */
170 	uint32_t sc_stacr_read;		/* Read opcode of STAOPC of STACR */
171 	uint32_t sc_stacr_write;	/* Write opcode of STAOPC of STACR */
172 	uint32_t sc_stacr_bits;		/* misc bits of STACR */
173 	bool sc_stacr_completed;	/* Operation completed of STACR */
174 	int sc_htsize;			/* Hash Table size */
175 
176 	bus_dmamap_t sc_cddmamap;	/* control data dma map */
177 #define	sc_cddma	sc_cddmamap->dm_segs[0].ds_addr
178 
179 	/* Software state for transmit/receive descriptors. */
180 	struct emac_txsoft sc_txsoft[EMAC_TXQUEUELEN];
181 	struct emac_rxsoft sc_rxsoft[EMAC_NRXDESC];
182 
183 	/* Control data structures. */
184 	struct emac_control_data *sc_control_data;
185 #define	sc_txdescs	sc_control_data->ecd_txdesc
186 #define	sc_rxdescs	sc_control_data->ecd_rxdesc
187 
188 #ifdef EMAC_EVENT_COUNTERS
189 	struct evcnt sc_ev_rxintr;	/* Rx interrupts */
190 	struct evcnt sc_ev_txintr;	/* Tx interrupts */
191 	struct evcnt sc_ev_rxde;	/* Rx descriptor interrupts */
192 	struct evcnt sc_ev_txde;	/* Tx descriptor interrupts */
193 	struct evcnt sc_ev_intr;	/* General EMAC interrupts */
194 
195 	struct evcnt sc_ev_txreap;	/* Calls to Tx descriptor reaper */
196 	struct evcnt sc_ev_txsstall;	/* Tx stalled due to no txs */
197 	struct evcnt sc_ev_txdstall;	/* Tx stalled due to no txd */
198 	struct evcnt sc_ev_txdrop;	/* Tx packets dropped (too many segs) */
199 	struct evcnt sc_ev_tu;		/* Tx underrun */
200 #endif /* EMAC_EVENT_COUNTERS */
201 
202 	int sc_txfree;			/* number of free Tx descriptors */
203 	int sc_txnext;			/* next ready Tx descriptor */
204 
205 	int sc_txsfree;			/* number of free Tx jobs */
206 	int sc_txsnext;			/* next ready Tx job */
207 	int sc_txsdirty;		/* dirty Tx jobs */
208 
209 	int sc_rxptr;			/* next ready RX descriptor/descsoft */
210 
211 	void (*sc_rmii_enable)(device_t, int);		/* reduced MII enable */
212 	void (*sc_rmii_disable)(device_t, int);		/* reduced MII disable*/
213 	void (*sc_rmii_speed)(device_t, int, int);	/* reduced MII speed */
214 };
215 
216 #ifdef EMAC_EVENT_COUNTERS
217 #define	EMAC_EVCNT_INCR(ev)	(ev)->ev_count++
218 #else
219 #define	EMAC_EVCNT_INCR(ev)	/* nothing */
220 #endif
221 
222 #define	EMAC_CDTXADDR(sc, x)	((sc)->sc_cddma + EMAC_CDTXOFF((x)))
223 #define	EMAC_CDRXADDR(sc, x)	((sc)->sc_cddma + EMAC_CDRXOFF((x)))
224 
225 #define	EMAC_CDTXSYNC(sc, x, n, ops)					\
226 do {									\
227 	int __x, __n;							\
228 									\
229 	__x = (x);							\
230 	__n = (n);							\
231 									\
232 	/* If it will wrap around, sync to the end of the ring. */	\
233 	if ((__x + __n) > EMAC_NTXDESC) {				\
234 		bus_dmamap_sync((sc)->sc_dmat, (sc)->sc_cddmamap,	\
235 		    EMAC_CDTXOFF(__x), sizeof(struct mal_descriptor) *	\
236 		    (EMAC_NTXDESC - __x), (ops));			\
237 		__n -= (EMAC_NTXDESC - __x);				\
238 		__x = 0;						\
239 	}								\
240 									\
241 	/* Now sync whatever is left. */				\
242 	bus_dmamap_sync((sc)->sc_dmat, (sc)->sc_cddmamap,		\
243 	    EMAC_CDTXOFF(__x), sizeof(struct mal_descriptor) * __n, (ops)); \
244 } while (/*CONSTCOND*/0)
245 
246 #define	EMAC_CDRXSYNC(sc, x, ops)					\
247 do {									\
248 	bus_dmamap_sync((sc)->sc_dmat, (sc)->sc_cddmamap,		\
249 	    EMAC_CDRXOFF((x)), sizeof(struct mal_descriptor), (ops));	\
250 } while (/*CONSTCOND*/0)
251 
252 #define	EMAC_INIT_RXDESC(sc, x)						\
253 do {									\
254 	struct emac_rxsoft *__rxs = &(sc)->sc_rxsoft[(x)];		\
255 	struct mal_descriptor *__rxd = &(sc)->sc_rxdescs[(x)];		\
256 	struct mbuf *__m = __rxs->rxs_mbuf;				\
257 									\
258 	/*								\
259 	 * Note: We scoot the packet forward 2 bytes in the buffer	\
260 	 * so that the payload after the Ethernet header is aligned	\
261 	 * to a 4-byte boundary.					\
262 	 */								\
263 	__m->m_data = __m->m_ext.ext_buf + 2;				\
264 									\
265 	__rxd->md_data = __rxs->rxs_dmamap->dm_segs[0].ds_addr + 2;	\
266 	__rxd->md_data_len = __m->m_ext.ext_size - 2;			\
267 	__rxd->md_stat_ctrl = MAL_RX_EMPTY | MAL_RX_INTERRUPT |		\
268 	    /* Set wrap on last descriptor. */				\
269 	    (((x) == EMAC_NRXDESC - 1) ? MAL_RX_WRAP : 0);		\
270 	EMAC_CDRXSYNC((sc), (x), BUS_DMASYNC_PREREAD|BUS_DMASYNC_PREWRITE); \
271 } while (/*CONSTCOND*/0)
272 
273 #define	EMAC_WRITE(sc, reg, val) \
274 	bus_space_write_stream_4((sc)->sc_st, (sc)->sc_sh, (reg), (val))
275 #define	EMAC_READ(sc, reg) \
276 	bus_space_read_stream_4((sc)->sc_st, (sc)->sc_sh, (reg))
277 
278 #define	EMAC_SET_FILTER(aht, crc) \
279 do {									\
280 	(aht)[3 - (((crc) >> 26) >> 4)] |= 1 << (((crc) >> 26) & 0xf);	\
281 } while (/*CONSTCOND*/0)
282 #define	EMAC_SET_FILTER256(aht, crc) \
283 do {									\
284 	(aht)[7 - (((crc) >> 24) >> 5)] |= 1 << (((crc) >> 24) & 0x1f);	\
285 } while (/*CONSTCOND*/0)
286 
287 static int	emac_match(device_t, cfdata_t, void *);
288 static void	emac_attach(device_t, device_t, void *);
289 
290 static int	emac_intr(void *);
291 static void	emac_shutdown(void *);
292 
293 static void	emac_start(struct ifnet *);
294 static int	emac_ioctl(struct ifnet *, u_long, void *);
295 static int	emac_init(struct ifnet *);
296 static void	emac_stop(struct ifnet *, int);
297 static void	emac_watchdog(struct ifnet *);
298 
299 static int	emac_add_rxbuf(struct emac_softc *, int);
300 static void	emac_rxdrain(struct emac_softc *);
301 static int	emac_set_filter(struct emac_softc *);
302 static int	emac_txreap(struct emac_softc *);
303 
304 static void	emac_soft_reset(struct emac_softc *);
305 static void	emac_smart_reset(struct emac_softc *);
306 
307 static int	emac_mii_readreg(device_t, int, int);
308 static void	emac_mii_writereg(device_t, int, int, int);
309 static void	emac_mii_statchg(struct ifnet *);
310 static uint32_t	emac_mii_wait(struct emac_softc *);
311 static void	emac_mii_tick(void *);
312 
313 int		emac_copy_small = 0;
314 
315 CFATTACH_DECL_NEW(emac, sizeof(struct emac_softc),
316     emac_match, emac_attach, NULL, NULL);
317 
318 
319 static int
320 emac_match(device_t parent, cfdata_t cf, void *aux)
321 {
322 	struct opb_attach_args *oaa = aux;
323 
324 	/* match only on-chip ethernet devices */
325 	if (strcmp(oaa->opb_name, cf->cf_name) == 0)
326 		return 1;
327 
328 	return 0;
329 }
330 
331 static void
332 emac_attach(device_t parent, device_t self, void *aux)
333 {
334 	struct opb_attach_args *oaa = aux;
335 	struct emac_softc *sc = device_private(self);
336 	struct ifnet *ifp = &sc->sc_ethercom.ec_if;
337 	struct mii_data *mii = &sc->sc_mii;
338 	const char * xname = device_xname(self);
339 	bus_dma_segment_t seg;
340 	int error, i, nseg, opb_freq, opbc, mii_phy = MII_PHY_ANY;
341 	const uint8_t *enaddr;
342 	prop_dictionary_t dict = device_properties(self);
343 	prop_data_t ea;
344 
345 	bus_space_map(oaa->opb_bt, oaa->opb_addr, EMAC_NREG, 0, &sc->sc_sh);
346 
347 	sc->sc_dev = self;
348 	sc->sc_instance = oaa->opb_instance;
349 	sc->sc_st = oaa->opb_bt;
350 	sc->sc_dmat = oaa->opb_dmat;
351 
352 	callout_init(&sc->sc_callout, 0);
353 
354 	aprint_naive("\n");
355 	aprint_normal(": Ethernet Media Access Controller\n");
356 
357 	/* Fetch the Ethernet address. */
358 	ea = prop_dictionary_get(dict, "mac-address");
359 	if (ea == NULL) {
360 		aprint_error_dev(self, "unable to get mac-address property\n");
361 		return;
362 	}
363 	KASSERT(prop_object_type(ea) == PROP_TYPE_DATA);
364 	KASSERT(prop_data_size(ea) == ETHER_ADDR_LEN);
365 	enaddr = prop_data_data_nocopy(ea);
366 	aprint_normal_dev(self, "Ethernet address %s\n", ether_sprintf(enaddr));
367 
368 #if defined(EMAC_ZMII_PHY) || defined(EMAC_RGMII_PHY)
369 	/* Fetch the MII offset. */
370 	prop_dictionary_get_uint32(dict, "mii-phy", &mii_phy);
371 
372 #ifdef EMAC_ZMII_PHY
373 	if (oaa->opb_flags & OPB_FLAGS_EMAC_RMII_ZMII)
374 		zmii_attach(parent, sc->sc_instance, &sc->sc_rmii_enable,
375 		    &sc->sc_rmii_disable, &sc->sc_rmii_speed);
376 #endif
377 #ifdef EMAC_RGMII_PHY
378 	if (oaa->opb_flags & OPB_FLAGS_EMAC_RMII_RGMII)
379 		rgmii_attach(parent, sc->sc_instance, &sc->sc_rmii_enable,
380 		    &sc->sc_rmii_disable, &sc->sc_rmii_speed);
381 #endif
382 #endif
383 
384 	/*
385 	 * Allocate the control data structures, and create and load the
386 	 * DMA map for it.
387 	 */
388 	if ((error = bus_dmamem_alloc(sc->sc_dmat,
389 	    sizeof(struct emac_control_data), 0, 0, &seg, 1, &nseg, 0)) != 0) {
390 		aprint_error_dev(self,
391 		    "unable to allocate control data, error = %d\n", error);
392 		goto fail_0;
393 	}
394 
395 	if ((error = bus_dmamem_map(sc->sc_dmat, &seg, nseg,
396 	    sizeof(struct emac_control_data), (void **)&sc->sc_control_data,
397 	    BUS_DMA_COHERENT)) != 0) {
398 		aprint_error_dev(self,
399 		    "unable to map control data, error = %d\n", error);
400 		goto fail_1;
401 	}
402 
403 	if ((error = bus_dmamap_create(sc->sc_dmat,
404 	    sizeof(struct emac_control_data), 1,
405 	    sizeof(struct emac_control_data), 0, 0, &sc->sc_cddmamap)) != 0) {
406 		aprint_error_dev(self,
407 		    "unable to create control data DMA map, error = %d\n",
408 		    error);
409 		goto fail_2;
410 	}
411 
412 	if ((error = bus_dmamap_load(sc->sc_dmat, sc->sc_cddmamap,
413 	    sc->sc_control_data, sizeof(struct emac_control_data), NULL,
414 	    0)) != 0) {
415 		aprint_error_dev(self,
416 		    "unable to load control data DMA map, error = %d\n", error);
417 		goto fail_3;
418 	}
419 
420 	/*
421 	 * Create the transmit buffer DMA maps.
422 	 */
423 	for (i = 0; i < EMAC_TXQUEUELEN; i++) {
424 		if ((error = bus_dmamap_create(sc->sc_dmat, MCLBYTES,
425 		    EMAC_NTXSEGS, MCLBYTES, 0, 0,
426 		    &sc->sc_txsoft[i].txs_dmamap)) != 0) {
427 			aprint_error_dev(self,
428 			    "unable to create tx DMA map %d, error = %d\n",
429 			    i, error);
430 			goto fail_4;
431 		}
432 	}
433 
434 	/*
435 	 * Create the receive buffer DMA maps.
436 	 */
437 	for (i = 0; i < EMAC_NRXDESC; i++) {
438 		if ((error = bus_dmamap_create(sc->sc_dmat, MCLBYTES, 1,
439 		    MCLBYTES, 0, 0, &sc->sc_rxsoft[i].rxs_dmamap)) != 0) {
440 			aprint_error_dev(self,
441 			    "unable to create rx DMA map %d, error = %d\n",
442 			    i, error);
443 			goto fail_5;
444 		}
445 		sc->sc_rxsoft[i].rxs_mbuf = NULL;
446 	}
447 
448 	/* Soft Reset the EMAC.  The chip to a known state. */
449 	emac_soft_reset(sc);
450 
451 	opb_freq = opb_get_frequency();
452 	switch (opb_freq) {
453 	case  50000000: opbc =  STACR_OPBC_50MHZ; break;
454 	case  66666666: opbc =  STACR_OPBC_66MHZ; break;
455 	case  83333333: opbc =  STACR_OPBC_83MHZ; break;
456 	case 100000000: opbc = STACR_OPBC_100MHZ; break;
457 
458 	default:
459 		if (opb_freq > 100000000) {
460 			opbc = STACR_OPBC_A100MHZ;
461 			break;
462 		}
463 		aprint_error_dev(self, "unsupport OPB frequency %dMHz\n",
464 		    opb_freq / 1000 / 1000);
465 		goto fail_5;
466 	}
467 	if (oaa->opb_flags & OPB_FLAGS_EMAC_GBE) {
468 		sc->sc_mr1 =
469 		    MR1_RFS_GBE(MR1__FS_16KB)	|
470 		    MR1_TFS_GBE(MR1__FS_16KB)	|
471 		    MR1_TR0_MULTIPLE		|
472 		    MR1_OBCI(opbc);
473 		sc->sc_ethercom.ec_capabilities |= ETHERCAP_JUMBO_MTU;
474 
475 		if (oaa->opb_flags & OPB_FLAGS_EMAC_STACV2) {
476 			sc->sc_stacr_read = STACR_STAOPC_READ;
477 			sc->sc_stacr_write = STACR_STAOPC_WRITE;
478 			sc->sc_stacr_bits = STACR_OC;
479 			sc->sc_stacr_completed = false;
480 		} else {
481 			sc->sc_stacr_read = STACR_READ;
482 			sc->sc_stacr_write = STACR_WRITE;
483 			sc->sc_stacr_completed = true;
484 		}
485 	} else {
486 		/*
487 		 * Set up Mode Register 1 - set receive and transmit FIFOs to
488 		 * maximum size, allow transmit of multiple packets (only
489 		 * channel 0 is used).
490 		 *
491 		 * XXX: Allow pause packets??
492 		 */
493 		sc->sc_mr1 =
494 		    MR1_RFS(MR1__FS_4KB) |
495 		    MR1_TFS(MR1__FS_2KB) |
496 		    MR1_TR0_MULTIPLE;
497 
498 		sc->sc_stacr_read = STACR_READ;
499 		sc->sc_stacr_write = STACR_WRITE;
500 		sc->sc_stacr_bits = STACR_OPBC(opbc);
501 		sc->sc_stacr_completed = true;
502 	}
503 
504 	intr_establish(oaa->opb_irq, IST_LEVEL, IPL_NET, emac_intr, sc);
505 	mal_intr_establish(sc->sc_instance, sc);
506 
507 	if (oaa->opb_flags & OPB_FLAGS_EMAC_HT256)
508 		sc->sc_htsize = 256;
509 	else
510 		sc->sc_htsize = 64;
511 
512 	/* Clear all interrupts */
513 	EMAC_WRITE(sc, EMAC_ISR, ISR_ALL);
514 
515 	/*
516 	 * Initialise the media structures.
517 	 */
518 	mii->mii_ifp = ifp;
519 	mii->mii_readreg = emac_mii_readreg;
520 	mii->mii_writereg = emac_mii_writereg;
521 	mii->mii_statchg = emac_mii_statchg;
522 
523 	sc->sc_ethercom.ec_mii = mii;
524 	ifmedia_init(&mii->mii_media, 0, ether_mediachange, ether_mediastatus);
525 	mii_attach(self, mii, 0xffffffff, mii_phy, MII_OFFSET_ANY, 0);
526 	if (LIST_FIRST(&mii->mii_phys) == NULL) {
527 		ifmedia_add(&mii->mii_media, IFM_ETHER|IFM_NONE, 0, NULL);
528 		ifmedia_set(&mii->mii_media, IFM_ETHER|IFM_NONE);
529 	} else
530 		ifmedia_set(&mii->mii_media, IFM_ETHER|IFM_AUTO);
531 
532 	ifp = &sc->sc_ethercom.ec_if;
533 	strcpy(ifp->if_xname, xname);
534 	ifp->if_softc = sc;
535 	ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST;
536 	ifp->if_start = emac_start;
537 	ifp->if_ioctl = emac_ioctl;
538 	ifp->if_init = emac_init;
539 	ifp->if_stop = emac_stop;
540 	ifp->if_watchdog = emac_watchdog;
541 	IFQ_SET_READY(&ifp->if_snd);
542 
543 	/*
544 	 * We can support 802.1Q VLAN-sized frames.
545 	 */
546 	sc->sc_ethercom.ec_capabilities |= ETHERCAP_VLAN_MTU;
547 
548 	/*
549 	 * Attach the interface.
550 	 */
551 	if_attach(ifp);
552 	ether_ifattach(ifp, enaddr);
553 
554 #ifdef EMAC_EVENT_COUNTERS
555 	/*
556 	 * Attach the event counters.
557 	 */
558 	evcnt_attach_dynamic(&sc->sc_ev_txintr, EVCNT_TYPE_INTR,
559 	    NULL, xname, "txintr");
560 	evcnt_attach_dynamic(&sc->sc_ev_rxintr, EVCNT_TYPE_INTR,
561 	    NULL, xname, "rxintr");
562 	evcnt_attach_dynamic(&sc->sc_ev_txde, EVCNT_TYPE_INTR,
563 	    NULL, xname, "txde");
564 	evcnt_attach_dynamic(&sc->sc_ev_rxde, EVCNT_TYPE_INTR,
565 	    NULL, xname, "rxde");
566 	evcnt_attach_dynamic(&sc->sc_ev_intr, EVCNT_TYPE_INTR,
567 	    NULL, xname, "intr");
568 
569 	evcnt_attach_dynamic(&sc->sc_ev_txreap, EVCNT_TYPE_MISC,
570 	    NULL, xname, "txreap");
571 	evcnt_attach_dynamic(&sc->sc_ev_txsstall, EVCNT_TYPE_MISC,
572 	    NULL, xname, "txsstall");
573 	evcnt_attach_dynamic(&sc->sc_ev_txdstall, EVCNT_TYPE_MISC,
574 	    NULL, xname, "txdstall");
575 	evcnt_attach_dynamic(&sc->sc_ev_txdrop, EVCNT_TYPE_MISC,
576 	    NULL, xname, "txdrop");
577 	evcnt_attach_dynamic(&sc->sc_ev_tu, EVCNT_TYPE_MISC,
578 	    NULL, xname, "tu");
579 #endif /* EMAC_EVENT_COUNTERS */
580 
581 	/*
582 	 * Make sure the interface is shutdown during reboot.
583 	 */
584 	sc->sc_sdhook = shutdownhook_establish(emac_shutdown, sc);
585 	if (sc->sc_sdhook == NULL)
586 		aprint_error_dev(self,
587 		    "WARNING: unable to establish shutdown hook\n");
588 
589 	return;
590 
591 	/*
592 	 * Free any resources we've allocated during the failed attach
593 	 * attempt.  Do this in reverse order and fall through.
594 	 */
595 fail_5:
596 	for (i = 0; i < EMAC_NRXDESC; i++) {
597 		if (sc->sc_rxsoft[i].rxs_dmamap != NULL)
598 			bus_dmamap_destroy(sc->sc_dmat,
599 			    sc->sc_rxsoft[i].rxs_dmamap);
600 	}
601 fail_4:
602 	for (i = 0; i < EMAC_TXQUEUELEN; i++) {
603 		if (sc->sc_txsoft[i].txs_dmamap != NULL)
604 			bus_dmamap_destroy(sc->sc_dmat,
605 			    sc->sc_txsoft[i].txs_dmamap);
606 	}
607 	bus_dmamap_unload(sc->sc_dmat, sc->sc_cddmamap);
608 fail_3:
609 	bus_dmamap_destroy(sc->sc_dmat, sc->sc_cddmamap);
610 fail_2:
611 	bus_dmamem_unmap(sc->sc_dmat, (void *)sc->sc_control_data,
612 	    sizeof(struct emac_control_data));
613 fail_1:
614 	bus_dmamem_free(sc->sc_dmat, &seg, nseg);
615 fail_0:
616 	return;
617 }
618 
619 /*
620  * EMAC General interrupt handler
621  */
622 static int
623 emac_intr(void *arg)
624 {
625 	struct emac_softc *sc = arg;
626 	uint32_t status;
627 
628 	EMAC_EVCNT_INCR(&sc->sc_ev_intr);
629 	status = EMAC_READ(sc, EMAC_ISR);
630 
631 	/* Clear the interrupt status bits. */
632 	EMAC_WRITE(sc, EMAC_ISR, status);
633 
634 	return 1;
635 }
636 
637 static void
638 emac_shutdown(void *arg)
639 {
640 	struct emac_softc *sc = arg;
641 
642 	emac_stop(&sc->sc_ethercom.ec_if, 0);
643 }
644 
645 
646 /*
647  * ifnet interface functions
648  */
649 
650 static void
651 emac_start(struct ifnet *ifp)
652 {
653 	struct emac_softc *sc = ifp->if_softc;
654 	struct mbuf *m0;
655 	struct emac_txsoft *txs;
656 	bus_dmamap_t dmamap;
657 	int error, firsttx, nexttx, lasttx, ofree, seg;
658 
659 	lasttx = 0;	/* XXX gcc */
660 
661 	if ((ifp->if_flags & (IFF_RUNNING|IFF_OACTIVE)) != IFF_RUNNING)
662 		return;
663 
664 	/*
665 	 * Remember the previous number of free descriptors.
666 	 */
667 	ofree = sc->sc_txfree;
668 
669 	/*
670 	 * Loop through the send queue, setting up transmit descriptors
671 	 * until we drain the queue, or use up all available transmit
672 	 * descriptors.
673 	 */
674 	for (;;) {
675 		/* Grab a packet off the queue. */
676 		IFQ_POLL(&ifp->if_snd, m0);
677 		if (m0 == NULL)
678 			break;
679 
680 		/*
681 		 * Get a work queue entry.  Reclaim used Tx descriptors if
682 		 * we are running low.
683 		 */
684 		if (sc->sc_txsfree < EMAC_TXQUEUE_GC) {
685 			emac_txreap(sc);
686 			if (sc->sc_txsfree == 0) {
687 				EMAC_EVCNT_INCR(&sc->sc_ev_txsstall);
688 				break;
689 			}
690 		}
691 
692 		txs = &sc->sc_txsoft[sc->sc_txsnext];
693 		dmamap = txs->txs_dmamap;
694 
695 		/*
696 		 * Load the DMA map.  If this fails, the packet either
697 		 * didn't fit in the alloted number of segments, or we
698 		 * were short on resources.  In this case, we'll copy
699 		 * and try again.
700 		 */
701 		error = bus_dmamap_load_mbuf(sc->sc_dmat, dmamap, m0,
702 		    BUS_DMA_WRITE|BUS_DMA_NOWAIT);
703 		if (error) {
704 			if (error == EFBIG) {
705 				EMAC_EVCNT_INCR(&sc->sc_ev_txdrop);
706 				aprint_error_ifnet(ifp,
707 				    "Tx packet consumes too many "
708 				    "DMA segments, dropping...\n");
709 				    IFQ_DEQUEUE(&ifp->if_snd, m0);
710 				    m_freem(m0);
711 				    continue;
712 			}
713 			/* Short on resources, just stop for now. */
714 			break;
715 		}
716 
717 		/*
718 		 * Ensure we have enough descriptors free to describe
719 		 * the packet.
720 		 */
721 		if (dmamap->dm_nsegs > sc->sc_txfree) {
722 			/*
723 			 * Not enough free descriptors to transmit this
724 			 * packet.  We haven't committed anything yet,
725 			 * so just unload the DMA map, put the packet
726 			 * back on the queue, and punt.  Notify the upper
727 			 * layer that there are not more slots left.
728 			 *
729 			 */
730 			ifp->if_flags |= IFF_OACTIVE;
731 			bus_dmamap_unload(sc->sc_dmat, dmamap);
732 			EMAC_EVCNT_INCR(&sc->sc_ev_txdstall);
733 			break;
734 		}
735 
736 		IFQ_DEQUEUE(&ifp->if_snd, m0);
737 
738 		/*
739 		 * WE ARE NOW COMMITTED TO TRANSMITTING THE PACKET.
740 		 */
741 
742 		/* Sync the DMA map. */
743 		bus_dmamap_sync(sc->sc_dmat, dmamap, 0, dmamap->dm_mapsize,
744 		    BUS_DMASYNC_PREWRITE);
745 
746 		/*
747 		 * Store a pointer to the packet so that we can free it
748 		 * later.
749 		 */
750 		txs->txs_mbuf = m0;
751 		txs->txs_firstdesc = sc->sc_txnext;
752 		txs->txs_ndesc = dmamap->dm_nsegs;
753 
754 		/*
755 		 * Initialize the transmit descriptor.
756 		 */
757 		firsttx = sc->sc_txnext;
758 		for (nexttx = sc->sc_txnext, seg = 0;
759 		     seg < dmamap->dm_nsegs;
760 		     seg++, nexttx = EMAC_NEXTTX(nexttx)) {
761 			struct mal_descriptor *txdesc =
762 			    &sc->sc_txdescs[nexttx];
763 
764 			/*
765 			 * If this is the first descriptor we're
766 			 * enqueueing, don't set the TX_READY bit just
767 			 * yet.  That could cause a race condition.
768 			 * We'll do it below.
769 			 */
770 			txdesc->md_data = dmamap->dm_segs[seg].ds_addr;
771 			txdesc->md_data_len = dmamap->dm_segs[seg].ds_len;
772 			txdesc->md_stat_ctrl =
773 			    (txdesc->md_stat_ctrl & MAL_TX_WRAP) |
774 			    (nexttx == firsttx ? 0 : MAL_TX_READY) |
775 			    EMAC_TXC_GFCS | EMAC_TXC_GPAD;
776 			lasttx = nexttx;
777 		}
778 
779 		/* Set the LAST bit on the last segment. */
780 		sc->sc_txdescs[lasttx].md_stat_ctrl |= MAL_TX_LAST;
781 
782 		/*
783 		 * Set up last segment descriptor to send an interrupt after
784 		 * that descriptor is transmitted, and bypass existing Tx
785 		 * descriptor reaping method (for now...).
786 		 */
787 		sc->sc_txdescs[lasttx].md_stat_ctrl |= MAL_TX_INTERRUPT;
788 
789 
790 		txs->txs_lastdesc = lasttx;
791 
792 		/* Sync the descriptors we're using. */
793 		EMAC_CDTXSYNC(sc, sc->sc_txnext, dmamap->dm_nsegs,
794 		    BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);
795 
796 		/*
797 		 * The entire packet chain is set up.  Give the
798 		 * first descriptor to the chip now.
799 		 */
800 		sc->sc_txdescs[firsttx].md_stat_ctrl |= MAL_TX_READY;
801 		EMAC_CDTXSYNC(sc, firsttx, 1,
802 		    BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);
803 		/*
804 		 * Tell the EMAC that a new packet is available.
805 		 */
806 		EMAC_WRITE(sc, EMAC_TMR0, TMR0_GNP0 | TMR0_TFAE_2);
807 
808 		/* Advance the tx pointer. */
809 		sc->sc_txfree -= txs->txs_ndesc;
810 		sc->sc_txnext = nexttx;
811 
812 		sc->sc_txsfree--;
813 		sc->sc_txsnext = EMAC_NEXTTXS(sc->sc_txsnext);
814 
815 		/*
816 		 * Pass the packet to any BPF listeners.
817 		 */
818 		bpf_mtap(ifp, m0);
819 	}
820 
821 	if (sc->sc_txfree == 0)
822 		/* No more slots left; notify upper layer. */
823 		ifp->if_flags |= IFF_OACTIVE;
824 
825 	if (sc->sc_txfree != ofree)
826 		/* Set a watchdog timer in case the chip flakes out. */
827 		ifp->if_timer = 5;
828 }
829 
830 static int
831 emac_ioctl(struct ifnet *ifp, u_long cmd, void *data)
832 {
833 	struct emac_softc *sc = ifp->if_softc;
834 	int s, error;
835 
836 	s = splnet();
837 
838 	switch (cmd) {
839 	case SIOCSIFMTU:
840 	{
841 		struct ifreq *ifr = (struct ifreq *)data;
842 		int maxmtu;
843 
844 		if (sc->sc_ethercom.ec_capabilities & ETHERCAP_JUMBO_MTU)
845 			maxmtu = EMAC_MAX_MTU;
846 		else
847 			maxmtu = ETHERMTU;
848 
849 		if (ifr->ifr_mtu < ETHERMIN || ifr->ifr_mtu > maxmtu)
850 			error = EINVAL;
851 		else if ((error = ifioctl_common(ifp, cmd, data)) != ENETRESET)
852 			break;
853 		else if (ifp->if_flags & IFF_UP)
854 			error = emac_init(ifp);
855 		else
856 			error = 0;
857 		break;
858 	}
859 
860 	default:
861 		error = ether_ioctl(ifp, cmd, data);
862 		if (error == ENETRESET) {
863 			/*
864 			 * Multicast list has changed; set the hardware filter
865 			 * accordingly.
866 			 */
867 			if (ifp->if_flags & IFF_RUNNING)
868 				error = emac_set_filter(sc);
869 			else
870 				error = 0;
871 		}
872 	}
873 
874 	/* try to get more packets going */
875 	emac_start(ifp);
876 
877 	splx(s);
878 	return error;
879 }
880 
881 static int
882 emac_init(struct ifnet *ifp)
883 {
884 	struct emac_softc *sc = ifp->if_softc;
885 	struct emac_rxsoft *rxs;
886 	const uint8_t *enaddr = CLLADDR(ifp->if_sadl);
887 	int error, i;
888 
889 	error = 0;
890 
891 	/* Cancel any pending I/O. */
892 	emac_stop(ifp, 0);
893 
894 	/* Reset the chip to a known state. */
895 	emac_soft_reset(sc);
896 
897 	/*
898 	 * Initialise the transmit descriptor ring.
899 	 */
900 	memset(sc->sc_txdescs, 0, sizeof(sc->sc_txdescs));
901 	/* set wrap on last descriptor */
902 	sc->sc_txdescs[EMAC_NTXDESC - 1].md_stat_ctrl |= MAL_TX_WRAP;
903 	EMAC_CDTXSYNC(sc, 0, EMAC_NTXDESC,
904 	    BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);
905 	sc->sc_txfree = EMAC_NTXDESC;
906 	sc->sc_txnext = 0;
907 
908 	/*
909 	 * Initialise the transmit job descriptors.
910 	 */
911 	for (i = 0; i < EMAC_TXQUEUELEN; i++)
912 		sc->sc_txsoft[i].txs_mbuf = NULL;
913 	sc->sc_txsfree = EMAC_TXQUEUELEN;
914 	sc->sc_txsnext = 0;
915 	sc->sc_txsdirty = 0;
916 
917 	/*
918 	 * Initialise the receiver descriptor and receive job
919 	 * descriptor rings.
920 	 */
921 	for (i = 0; i < EMAC_NRXDESC; i++) {
922 		rxs = &sc->sc_rxsoft[i];
923 		if (rxs->rxs_mbuf == NULL) {
924 			if ((error = emac_add_rxbuf(sc, i)) != 0) {
925 				aprint_error_ifnet(ifp,
926 				    "unable to allocate or map rx buffer %d,"
927 				    " error = %d\n",
928 				    i, error);
929 				/*
930 				 * XXX Should attempt to run with fewer receive
931 				 * XXX buffers instead of just failing.
932 				 */
933 				emac_rxdrain(sc);
934 				goto out;
935 			}
936 		} else
937 			EMAC_INIT_RXDESC(sc, i);
938 	}
939 	sc->sc_rxptr = 0;
940 
941 	/*
942 	 * Set the current media.
943 	 */
944 	if ((error = ether_mediachange(ifp)) != 0)
945 		goto out;
946 
947 	/*
948 	 * Load the MAC address.
949 	 */
950 	EMAC_WRITE(sc, EMAC_IAHR, enaddr[0] << 8 | enaddr[1]);
951 	EMAC_WRITE(sc, EMAC_IALR,
952 	    enaddr[2] << 24 | enaddr[3] << 16 | enaddr[4] << 8 | enaddr[5]);
953 
954 	/* Enable the transmit and receive channel on the MAL. */
955 	error = mal_start(sc->sc_instance,
956 	    EMAC_CDTXADDR(sc, 0), EMAC_CDRXADDR(sc, 0));
957 	if (error)
958 		goto out;
959 
960 	sc->sc_mr1 &= ~MR1_JPSM;
961 	if (ifp->if_mtu > ETHERMTU)
962 		/* Enable Jumbo Packet Support Mode */
963 		sc->sc_mr1 |= MR1_JPSM;
964 
965 	/* Set fifos, media modes. */
966 	EMAC_WRITE(sc, EMAC_MR1, sc->sc_mr1);
967 
968 	/*
969 	 * Enable Individual and (possibly) Broadcast Address modes,
970 	 * runt packets, and strip padding.
971 	 */
972 	EMAC_WRITE(sc, EMAC_RMR, RMR_IAE | RMR_RRP | RMR_SP | RMR_TFAE_2 |
973 	    (ifp->if_flags & IFF_PROMISC ? RMR_PME : 0) |
974 	    (ifp->if_flags & IFF_BROADCAST ? RMR_BAE : 0));
975 
976 	/*
977 	 * Set multicast filter.
978 	 */
979 	emac_set_filter(sc);
980 
981 	/*
982 	 * Set low- and urgent-priority request thresholds.
983 	 */
984 	EMAC_WRITE(sc, EMAC_TMR1,
985 	    ((7 << TMR1_TLR_SHIFT) & TMR1_TLR_MASK) | /* 16 word burst */
986 	    ((15 << TMR1_TUR_SHIFT) & TMR1_TUR_MASK));
987 	/*
988 	 * Set Transmit Request Threshold Register.
989 	 */
990 	EMAC_WRITE(sc, EMAC_TRTR, TRTR_256);
991 
992 	/*
993 	 * Set high and low receive watermarks.
994 	 */
995 	EMAC_WRITE(sc, EMAC_RWMR,
996 	    30 << RWMR_RLWM_SHIFT | 64 << RWMR_RLWM_SHIFT);
997 
998 	/*
999 	 * Set frame gap.
1000 	 */
1001 	EMAC_WRITE(sc, EMAC_IPGVR, 8);
1002 
1003 	/*
1004 	 * Set interrupt status enable bits for EMAC.
1005 	 */
1006 	EMAC_WRITE(sc, EMAC_ISER,
1007 	    ISR_TXPE |		/* TX Parity Error */
1008 	    ISR_RXPE |		/* RX Parity Error */
1009 	    ISR_TXUE |		/* TX Underrun Event */
1010 	    ISR_RXOE |		/* RX Overrun Event */
1011 	    ISR_OVR  |		/* Overrun Error */
1012 	    ISR_PP   |		/* Pause Packet */
1013 	    ISR_BP   |		/* Bad Packet */
1014 	    ISR_RP   |		/* Runt Packet */
1015 	    ISR_SE   |		/* Short Event */
1016 	    ISR_ALE  |		/* Alignment Error */
1017 	    ISR_BFCS |		/* Bad FCS */
1018 	    ISR_PTLE |		/* Packet Too Long Error */
1019 	    ISR_ORE  |		/* Out of Range Error */
1020 	    ISR_IRE  |		/* In Range Error */
1021 	    ISR_SE0  |		/* Signal Quality Error 0 (SQE) */
1022 	    ISR_TE0  |		/* Transmit Error 0 */
1023 	    ISR_MOS  |		/* MMA Operation Succeeded */
1024 	    ISR_MOF);		/* MMA Operation Failed */
1025 
1026 	/*
1027 	 * Enable the transmit and receive channel on the EMAC.
1028 	 */
1029 	EMAC_WRITE(sc, EMAC_MR0, MR0_TXE | MR0_RXE);
1030 
1031 	/*
1032 	 * Start the one second MII clock.
1033 	 */
1034 	callout_reset(&sc->sc_callout, hz, emac_mii_tick, sc);
1035 
1036 	/*
1037 	 * ... all done!
1038 	 */
1039 	ifp->if_flags |= IFF_RUNNING;
1040 	ifp->if_flags &= ~IFF_OACTIVE;
1041 
1042  out:
1043 	if (error) {
1044 		ifp->if_flags &= ~(IFF_RUNNING | IFF_OACTIVE);
1045 		ifp->if_timer = 0;
1046 		aprint_error_ifnet(ifp, "interface not running\n");
1047 	}
1048 	return error;
1049 }
1050 
1051 static void
1052 emac_stop(struct ifnet *ifp, int disable)
1053 {
1054 	struct emac_softc *sc = ifp->if_softc;
1055 	struct emac_txsoft *txs;
1056 	int i;
1057 
1058 	/* Stop the one second clock. */
1059 	callout_stop(&sc->sc_callout);
1060 
1061 	/* Down the MII */
1062 	mii_down(&sc->sc_mii);
1063 
1064 	/* Disable interrupts. */
1065 	EMAC_WRITE(sc, EMAC_ISER, 0);
1066 
1067 	/* Disable the receive and transmit channels. */
1068 	mal_stop(sc->sc_instance);
1069 
1070 	/* Disable the transmit enable and receive MACs. */
1071 	EMAC_WRITE(sc, EMAC_MR0,
1072 	    EMAC_READ(sc, EMAC_MR0) & ~(MR0_TXE | MR0_RXE));
1073 
1074 	/* Release any queued transmit buffers. */
1075 	for (i = 0; i < EMAC_TXQUEUELEN; i++) {
1076 		txs = &sc->sc_txsoft[i];
1077 		if (txs->txs_mbuf != NULL) {
1078 			bus_dmamap_unload(sc->sc_dmat, txs->txs_dmamap);
1079 			m_freem(txs->txs_mbuf);
1080 			txs->txs_mbuf = NULL;
1081 		}
1082 	}
1083 
1084 	if (disable)
1085 		emac_rxdrain(sc);
1086 
1087 	/*
1088 	 * Mark the interface down and cancel the watchdog timer.
1089 	 */
1090 	ifp->if_flags &= ~(IFF_RUNNING | IFF_OACTIVE);
1091 	ifp->if_timer = 0;
1092 }
1093 
1094 static void
1095 emac_watchdog(struct ifnet *ifp)
1096 {
1097 	struct emac_softc *sc = ifp->if_softc;
1098 
1099 	/*
1100 	 * Since we're not interrupting every packet, sweep
1101 	 * up before we report an error.
1102 	 */
1103 	emac_txreap(sc);
1104 
1105 	if (sc->sc_txfree != EMAC_NTXDESC) {
1106 		aprint_error_ifnet(ifp,
1107 		    "device timeout (txfree %d txsfree %d txnext %d)\n",
1108 		    sc->sc_txfree, sc->sc_txsfree, sc->sc_txnext);
1109 		ifp->if_oerrors++;
1110 
1111 		/* Reset the interface. */
1112 		(void)emac_init(ifp);
1113 	} else if (ifp->if_flags & IFF_DEBUG)
1114 		aprint_error_ifnet(ifp, "recovered from device timeout\n");
1115 
1116 	/* try to get more packets going */
1117 	emac_start(ifp);
1118 }
1119 
1120 static int
1121 emac_add_rxbuf(struct emac_softc *sc, int idx)
1122 {
1123 	struct emac_rxsoft *rxs = &sc->sc_rxsoft[idx];
1124 	struct mbuf *m;
1125 	int error;
1126 
1127 	MGETHDR(m, M_DONTWAIT, MT_DATA);
1128 	if (m == NULL)
1129 		return ENOBUFS;
1130 
1131 	MCLGET(m, M_DONTWAIT);
1132 	if ((m->m_flags & M_EXT) == 0) {
1133 		m_freem(m);
1134 		return ENOBUFS;
1135 	}
1136 
1137 	if (rxs->rxs_mbuf != NULL)
1138 		bus_dmamap_unload(sc->sc_dmat, rxs->rxs_dmamap);
1139 
1140 	rxs->rxs_mbuf = m;
1141 
1142 	error = bus_dmamap_load(sc->sc_dmat, rxs->rxs_dmamap,
1143 	    m->m_ext.ext_buf, m->m_ext.ext_size, NULL, BUS_DMA_NOWAIT);
1144 	if (error) {
1145 		aprint_error_dev(sc->sc_dev,
1146 		    "can't load rx DMA map %d, error = %d\n", idx, error);
1147 		panic("emac_add_rxbuf");		/* XXX */
1148 	}
1149 
1150 	bus_dmamap_sync(sc->sc_dmat, rxs->rxs_dmamap, 0,
1151 	    rxs->rxs_dmamap->dm_mapsize, BUS_DMASYNC_PREREAD);
1152 
1153 	EMAC_INIT_RXDESC(sc, idx);
1154 
1155 	return 0;
1156 }
1157 
1158 static void
1159 emac_rxdrain(struct emac_softc *sc)
1160 {
1161 	struct emac_rxsoft *rxs;
1162 	int i;
1163 
1164 	for (i = 0; i < EMAC_NRXDESC; i++) {
1165 		rxs = &sc->sc_rxsoft[i];
1166 		if (rxs->rxs_mbuf != NULL) {
1167 			bus_dmamap_unload(sc->sc_dmat, rxs->rxs_dmamap);
1168 			m_freem(rxs->rxs_mbuf);
1169 			rxs->rxs_mbuf = NULL;
1170 		}
1171 	}
1172 }
1173 
1174 static int
1175 emac_set_filter(struct emac_softc *sc)
1176 {
1177 	struct ether_multistep step;
1178 	struct ether_multi *enm;
1179 	struct ifnet *ifp = &sc->sc_ethercom.ec_if;
1180 	uint32_t rmr, crc, mask, tmp, reg, gaht[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
1181 	int regs, cnt = 0, i;
1182 
1183 	if (sc->sc_htsize == 256) {
1184 		reg = EMAC_GAHT256(0);
1185 		regs = 8;
1186 	} else {
1187 		reg = EMAC_GAHT64(0);
1188 		regs = 4;
1189 	}
1190 	mask = (1ULL << (sc->sc_htsize / regs)) - 1;
1191 
1192 	rmr = EMAC_READ(sc, EMAC_RMR);
1193 	rmr &= ~(RMR_PMME | RMR_MAE);
1194 	ifp->if_flags &= ~IFF_ALLMULTI;
1195 
1196 	ETHER_FIRST_MULTI(step, &sc->sc_ethercom, enm);
1197 	while (enm != NULL) {
1198 		if (memcmp(enm->enm_addrlo,
1199 		    enm->enm_addrhi, ETHER_ADDR_LEN) != 0) {
1200 			/*
1201 			 * We must listen to a range of multicast addresses.
1202 			 * For now, just accept all multicasts, rather than
1203 			 * trying to set only those filter bits needed to match
1204 			 * the range.  (At this time, the only use of address
1205 			 * ranges is for IP multicast routing, for which the
1206 			 * range is big enough to require all bits set.)
1207 			 */
1208 			gaht[0] = gaht[1] = gaht[2] = gaht[3] =
1209 			    gaht[4] = gaht[5] = gaht[6] = gaht[7] = mask;
1210 			break;
1211 		}
1212 
1213 		crc = ether_crc32_be(enm->enm_addrlo, ETHER_ADDR_LEN);
1214 
1215 		if (sc->sc_htsize == 256)
1216 			EMAC_SET_FILTER256(gaht, crc);
1217 		else
1218 			EMAC_SET_FILTER(gaht, crc);
1219 
1220 		ETHER_NEXT_MULTI(step, enm);
1221 		cnt++;
1222 	}
1223 
1224 	for (i = 1, tmp = gaht[0]; i < regs; i++)
1225 		tmp &= gaht[i];
1226 	if (tmp == mask) {
1227 		/* All categories are true. */
1228 		ifp->if_flags |= IFF_ALLMULTI;
1229 		rmr |= RMR_PMME;
1230 	} else if (cnt != 0) {
1231 		/* Some categories are true. */
1232 		for (i = 0; i < regs; i++)
1233 			EMAC_WRITE(sc, reg + (i << 2), gaht[i]);
1234 		rmr |= RMR_MAE;
1235 	}
1236 	EMAC_WRITE(sc, EMAC_RMR, rmr);
1237 
1238 	return 0;
1239 }
1240 
1241 /*
1242  * Reap completed Tx descriptors.
1243  */
1244 static int
1245 emac_txreap(struct emac_softc *sc)
1246 {
1247 	struct ifnet *ifp = &sc->sc_ethercom.ec_if;
1248 	struct emac_txsoft *txs;
1249 	int handled, i;
1250 	uint32_t txstat;
1251 
1252 	EMAC_EVCNT_INCR(&sc->sc_ev_txreap);
1253 	handled = 0;
1254 
1255 	ifp->if_flags &= ~IFF_OACTIVE;
1256 
1257 	/*
1258 	 * Go through our Tx list and free mbufs for those
1259 	 * frames that have been transmitted.
1260 	 */
1261 	for (i = sc->sc_txsdirty; sc->sc_txsfree != EMAC_TXQUEUELEN;
1262 	    i = EMAC_NEXTTXS(i), sc->sc_txsfree++) {
1263 		txs = &sc->sc_txsoft[i];
1264 
1265 		EMAC_CDTXSYNC(sc, txs->txs_lastdesc,
1266 		    txs->txs_dmamap->dm_nsegs,
1267 		    BUS_DMASYNC_POSTREAD|BUS_DMASYNC_POSTWRITE);
1268 
1269 		txstat = sc->sc_txdescs[txs->txs_lastdesc].md_stat_ctrl;
1270 		if (txstat & MAL_TX_READY)
1271 			break;
1272 
1273 		handled = 1;
1274 
1275 		/*
1276 		 * Check for errors and collisions.
1277 		 */
1278 		if (txstat & (EMAC_TXS_UR | EMAC_TXS_ED))
1279 			ifp->if_oerrors++;
1280 
1281 #ifdef EMAC_EVENT_COUNTERS
1282 		if (txstat & EMAC_TXS_UR)
1283 			EMAC_EVCNT_INCR(&sc->sc_ev_tu);
1284 #endif /* EMAC_EVENT_COUNTERS */
1285 
1286 		if (txstat &
1287 		    (EMAC_TXS_EC | EMAC_TXS_MC | EMAC_TXS_SC | EMAC_TXS_LC)) {
1288 			if (txstat & EMAC_TXS_EC)
1289 				ifp->if_collisions += 16;
1290 			else if (txstat & EMAC_TXS_MC)
1291 				ifp->if_collisions += 2;	/* XXX? */
1292 			else if (txstat & EMAC_TXS_SC)
1293 				ifp->if_collisions++;
1294 			if (txstat & EMAC_TXS_LC)
1295 				ifp->if_collisions++;
1296 		} else
1297 			ifp->if_opackets++;
1298 
1299 		if (ifp->if_flags & IFF_DEBUG) {
1300 			if (txstat & EMAC_TXS_ED)
1301 				aprint_error_ifnet(ifp, "excessive deferral\n");
1302 			if (txstat & EMAC_TXS_EC)
1303 				aprint_error_ifnet(ifp,
1304 				    "excessive collisions\n");
1305 		}
1306 
1307 		sc->sc_txfree += txs->txs_ndesc;
1308 		bus_dmamap_sync(sc->sc_dmat, txs->txs_dmamap,
1309 		    0, txs->txs_dmamap->dm_mapsize, BUS_DMASYNC_POSTWRITE);
1310 		bus_dmamap_unload(sc->sc_dmat, txs->txs_dmamap);
1311 		m_freem(txs->txs_mbuf);
1312 		txs->txs_mbuf = NULL;
1313 	}
1314 
1315 	/* Update the dirty transmit buffer pointer. */
1316 	sc->sc_txsdirty = i;
1317 
1318 	/*
1319 	 * If there are no more pending transmissions, cancel the watchdog
1320 	 * timer.
1321 	 */
1322 	if (sc->sc_txsfree == EMAC_TXQUEUELEN)
1323 		ifp->if_timer = 0;
1324 
1325 	return handled;
1326 }
1327 
1328 
1329 /*
1330  * Reset functions
1331  */
1332 
1333 static void
1334 emac_soft_reset(struct emac_softc *sc)
1335 {
1336 	uint32_t sdr;
1337 	int t = 0;
1338 
1339 	/*
1340 	 * The PHY must provide a TX Clk in order perform a soft reset the
1341 	 * EMAC.  If none is present, select the internal clock,
1342 	 * SDR0_MFR[E0CS,E1CS].  After the soft reset, select the external
1343 	 * clock.
1344 	 */
1345 
1346 	sdr = mfsdr(DCR_SDR0_MFR);
1347 	sdr |= SDR0_MFR_ECS(sc->sc_instance);
1348 	mtsdr(DCR_SDR0_MFR, sdr);
1349 
1350 	EMAC_WRITE(sc, EMAC_MR0, MR0_SRST);
1351 
1352 	sdr = mfsdr(DCR_SDR0_MFR);
1353 	sdr &= ~SDR0_MFR_ECS(sc->sc_instance);
1354 	mtsdr(DCR_SDR0_MFR, sdr);
1355 
1356 	delay(5);
1357 
1358 	/* wait finish */
1359 	while (EMAC_READ(sc, EMAC_MR0) & MR0_SRST) {
1360 		if (++t == 1000000 /* 1sec XXXXX */) {
1361 			aprint_error_dev(sc->sc_dev, "Soft Reset failed\n");
1362 			return;
1363 		}
1364 		delay(1);
1365 	}
1366 }
1367 
1368 static void
1369 emac_smart_reset(struct emac_softc *sc)
1370 {
1371 	uint32_t mr0;
1372 	int t = 0;
1373 
1374 	mr0 = EMAC_READ(sc, EMAC_MR0);
1375 	if (mr0 & (MR0_TXE | MR0_RXE)) {
1376 		mr0 &= ~(MR0_TXE | MR0_RXE);
1377 		EMAC_WRITE(sc, EMAC_MR0, mr0);
1378 
1379 		/* wait idel state */
1380 		while ((EMAC_READ(sc, EMAC_MR0) & (MR0_TXI | MR0_RXI)) !=
1381 		    (MR0_TXI | MR0_RXI)) {
1382 			if (++t == 1000000 /* 1sec XXXXX */) {
1383 				aprint_error_dev(sc->sc_dev,
1384 				    "Smart Reset failed\n");
1385 				return;
1386 			}
1387 			delay(1);
1388 		}
1389 	}
1390 }
1391 
1392 
1393 /*
1394  * MII related functions
1395  */
1396 
1397 static int
1398 emac_mii_readreg(device_t self, int phy, int reg)
1399 {
1400 	struct emac_softc *sc = device_private(self);
1401 	uint32_t sta_reg;
1402 
1403 	if (sc->sc_rmii_enable)
1404 		sc->sc_rmii_enable(device_parent(self), sc->sc_instance);
1405 
1406 	/* wait for PHY data transfer to complete */
1407 	if (emac_mii_wait(sc))
1408 		goto fail;
1409 
1410 	sta_reg =
1411 	    sc->sc_stacr_read		|
1412 	    (reg << STACR_PRA_SHIFT)	|
1413 	    (phy << STACR_PCDA_SHIFT)	|
1414 	    sc->sc_stacr_bits;
1415 	EMAC_WRITE(sc, EMAC_STACR, sta_reg);
1416 
1417 	if (emac_mii_wait(sc))
1418 		goto fail;
1419 	sta_reg = EMAC_READ(sc, EMAC_STACR);
1420 
1421 	if (sc->sc_rmii_disable)
1422 		sc->sc_rmii_disable(device_parent(self), sc->sc_instance);
1423 
1424 	if (sta_reg & STACR_PHYE)
1425 		return 0;
1426 	return sta_reg >> STACR_PHYD_SHIFT;
1427 
1428 fail:
1429 	if (sc->sc_rmii_disable)
1430 		sc->sc_rmii_disable(device_parent(self), sc->sc_instance);
1431 	return 0;
1432 }
1433 
1434 static void
1435 emac_mii_writereg(device_t self, int phy, int reg, int val)
1436 {
1437 	struct emac_softc *sc = device_private(self);
1438 	uint32_t sta_reg;
1439 
1440 	if (sc->sc_rmii_enable)
1441 		sc->sc_rmii_enable(device_parent(self), sc->sc_instance);
1442 
1443 	/* wait for PHY data transfer to complete */
1444 	if (emac_mii_wait(sc))
1445 		goto out;
1446 
1447 	sta_reg =
1448 	    (val << STACR_PHYD_SHIFT)	|
1449 	    sc->sc_stacr_write		|
1450 	    (reg << STACR_PRA_SHIFT)	|
1451 	    (phy << STACR_PCDA_SHIFT)	|
1452 	    sc->sc_stacr_bits;
1453 	EMAC_WRITE(sc, EMAC_STACR, sta_reg);
1454 
1455 	if (emac_mii_wait(sc))
1456 		goto out;
1457 	if (EMAC_READ(sc, EMAC_STACR) & STACR_PHYE)
1458 		aprint_error_dev(sc->sc_dev, "MII PHY Error\n");
1459 
1460 out:
1461 	if (sc->sc_rmii_disable)
1462 		sc->sc_rmii_disable(device_parent(self), sc->sc_instance);
1463 }
1464 
1465 static void
1466 emac_mii_statchg(struct ifnet *ifp)
1467 {
1468 	struct emac_softc *sc = ifp->if_softc;
1469 	struct mii_data *mii = &sc->sc_mii;
1470 
1471 	/*
1472 	 * MR1 can only be written immediately after a reset...
1473 	 */
1474 	emac_smart_reset(sc);
1475 
1476 	sc->sc_mr1 &= ~(MR1_FDE | MR1_ILE | MR1_EIFC | MR1_MF_MASK | MR1_IST);
1477 	if (mii->mii_media_active & IFM_FDX)
1478 		sc->sc_mr1 |= (MR1_FDE | MR1_EIFC | MR1_IST);
1479 	if (mii->mii_media_active & IFM_FLOW)
1480 		sc->sc_mr1 |= MR1_EIFC;
1481 	if (mii->mii_media_active & IFM_LOOP)
1482 		sc->sc_mr1 |= MR1_ILE;
1483 	switch (IFM_SUBTYPE(mii->mii_media_active)) {
1484 	case IFM_1000_T:
1485 		sc->sc_mr1 |= (MR1_MF_1000MBS | MR1_IST);
1486 		break;
1487 
1488 	case IFM_100_TX:
1489 		sc->sc_mr1 |= (MR1_MF_100MBS | MR1_IST);
1490 		break;
1491 
1492 	case IFM_10_T:
1493 		sc->sc_mr1 |= MR1_MF_10MBS;
1494 		break;
1495 
1496 	case IFM_NONE:
1497 		break;
1498 
1499 	default:
1500 		aprint_error_dev(sc->sc_dev, "unknown sub-type %d\n",
1501 		    IFM_SUBTYPE(mii->mii_media_active));
1502 		break;
1503 	}
1504 	if (sc->sc_rmii_speed)
1505 		sc->sc_rmii_speed(device_parent(sc->sc_dev), sc->sc_instance,
1506 		    IFM_SUBTYPE(mii->mii_media_active));
1507 
1508 	EMAC_WRITE(sc, EMAC_MR1, sc->sc_mr1);
1509 
1510 	/* Enable TX and RX if already RUNNING */
1511 	if (ifp->if_flags & IFF_RUNNING)
1512 		EMAC_WRITE(sc, EMAC_MR0, MR0_TXE | MR0_RXE);
1513 }
1514 
1515 static uint32_t
1516 emac_mii_wait(struct emac_softc *sc)
1517 {
1518 	int i;
1519 	uint32_t oc;
1520 
1521 	/* wait for PHY data transfer to complete */
1522 	i = 0;
1523 	oc = EMAC_READ(sc, EMAC_STACR) & STACR_OC;
1524 	while ((oc == STACR_OC) != sc->sc_stacr_completed) {
1525 		delay(7);
1526 		if (i++ > 5) {
1527 			aprint_error_dev(sc->sc_dev, "MII timed out\n");
1528 			return -1;
1529 		}
1530 		oc = EMAC_READ(sc, EMAC_STACR) & STACR_OC;
1531 	}
1532 	return 0;
1533 }
1534 
1535 static void
1536 emac_mii_tick(void *arg)
1537 {
1538 	struct emac_softc *sc = arg;
1539 	int s;
1540 
1541 	if (!device_is_active(sc->sc_dev))
1542 		return;
1543 
1544 	s = splnet();
1545 	mii_tick(&sc->sc_mii);
1546 	splx(s);
1547 
1548 	callout_reset(&sc->sc_callout, hz, emac_mii_tick, sc);
1549 }
1550 
1551 int
1552 emac_txeob_intr(void *arg)
1553 {
1554 	struct emac_softc *sc = arg;
1555 	int handled = 0;
1556 
1557 	EMAC_EVCNT_INCR(&sc->sc_ev_txintr);
1558 	handled |= emac_txreap(sc);
1559 
1560 	/* try to get more packets going */
1561 	emac_start(&sc->sc_ethercom.ec_if);
1562 
1563 	return handled;
1564 }
1565 
1566 int
1567 emac_rxeob_intr(void *arg)
1568 {
1569 	struct emac_softc *sc = arg;
1570 	struct ifnet *ifp = &sc->sc_ethercom.ec_if;
1571 	struct emac_rxsoft *rxs;
1572 	struct mbuf *m;
1573 	uint32_t rxstat;
1574 	int i, len;
1575 
1576 	EMAC_EVCNT_INCR(&sc->sc_ev_rxintr);
1577 
1578 	for (i = sc->sc_rxptr; ; i = EMAC_NEXTRX(i)) {
1579 		rxs = &sc->sc_rxsoft[i];
1580 
1581 		EMAC_CDRXSYNC(sc, i,
1582 		    BUS_DMASYNC_POSTREAD|BUS_DMASYNC_POSTWRITE);
1583 
1584 		rxstat = sc->sc_rxdescs[i].md_stat_ctrl;
1585 
1586 		if (rxstat & MAL_RX_EMPTY) {
1587 			/*
1588 			 * We have processed all of the receive buffers.
1589 			 */
1590 			/* Flush current empty descriptor */
1591 			EMAC_CDRXSYNC(sc, i,
1592 			    BUS_DMASYNC_PREREAD|BUS_DMASYNC_PREWRITE);
1593 			break;
1594 		}
1595 
1596 		/*
1597 		 * If an error occurred, update stats, clear the status
1598 		 * word, and leave the packet buffer in place.  It will
1599 		 * simply be reused the next time the ring comes around.
1600 		 */
1601 		if (rxstat & (EMAC_RXS_OE | EMAC_RXS_BP | EMAC_RXS_SE |
1602 		    EMAC_RXS_AE | EMAC_RXS_BFCS | EMAC_RXS_PTL | EMAC_RXS_ORE |
1603 		    EMAC_RXS_IRE)) {
1604 #define	PRINTERR(bit, str)					\
1605 			if (rxstat & (bit))			\
1606 				aprint_error_ifnet(ifp,		\
1607 				    "receive error: %s\n", str)
1608 			ifp->if_ierrors++;
1609 			PRINTERR(EMAC_RXS_OE, "overrun error");
1610 			PRINTERR(EMAC_RXS_BP, "bad packet");
1611 			PRINTERR(EMAC_RXS_RP, "runt packet");
1612 			PRINTERR(EMAC_RXS_SE, "short event");
1613 			PRINTERR(EMAC_RXS_AE, "alignment error");
1614 			PRINTERR(EMAC_RXS_BFCS, "bad FCS");
1615 			PRINTERR(EMAC_RXS_PTL, "packet too long");
1616 			PRINTERR(EMAC_RXS_ORE, "out of range error");
1617 			PRINTERR(EMAC_RXS_IRE, "in range error");
1618 #undef PRINTERR
1619 			EMAC_INIT_RXDESC(sc, i);
1620 			continue;
1621 		}
1622 
1623 		bus_dmamap_sync(sc->sc_dmat, rxs->rxs_dmamap, 0,
1624 		    rxs->rxs_dmamap->dm_mapsize, BUS_DMASYNC_POSTREAD);
1625 
1626 		/*
1627 		 * No errors; receive the packet.  Note, the 405GP emac
1628 		 * includes the CRC with every packet.
1629 		 */
1630 		len = sc->sc_rxdescs[i].md_data_len - ETHER_CRC_LEN;
1631 
1632 		/*
1633 		 * If the packet is small enough to fit in a
1634 		 * single header mbuf, allocate one and copy
1635 		 * the data into it.  This greatly reduces
1636 		 * memory consumption when we receive lots
1637 		 * of small packets.
1638 		 *
1639 		 * Otherwise, we add a new buffer to the receive
1640 		 * chain.  If this fails, we drop the packet and
1641 		 * recycle the old buffer.
1642 		 */
1643 		if (emac_copy_small != 0 && len <= MHLEN) {
1644 			MGETHDR(m, M_DONTWAIT, MT_DATA);
1645 			if (m == NULL)
1646 				goto dropit;
1647 			memcpy(mtod(m, void *),
1648 			    mtod(rxs->rxs_mbuf, void *), len);
1649 			EMAC_INIT_RXDESC(sc, i);
1650 			bus_dmamap_sync(sc->sc_dmat, rxs->rxs_dmamap, 0,
1651 			    rxs->rxs_dmamap->dm_mapsize,
1652 			    BUS_DMASYNC_PREREAD);
1653 		} else {
1654 			m = rxs->rxs_mbuf;
1655 			if (emac_add_rxbuf(sc, i) != 0) {
1656  dropit:
1657 				ifp->if_ierrors++;
1658 				EMAC_INIT_RXDESC(sc, i);
1659 				bus_dmamap_sync(sc->sc_dmat,
1660 				    rxs->rxs_dmamap, 0,
1661 				    rxs->rxs_dmamap->dm_mapsize,
1662 				    BUS_DMASYNC_PREREAD);
1663 				continue;
1664 			}
1665 		}
1666 
1667 		ifp->if_ipackets++;
1668 		m->m_pkthdr.rcvif = ifp;
1669 		m->m_pkthdr.len = m->m_len = len;
1670 
1671 		/*
1672 		 * Pass this up to any BPF listeners, but only
1673 		 * pass if up the stack if it's for us.
1674 		 */
1675 		bpf_mtap(ifp, m);
1676 
1677 		/* Pass it on. */
1678 		(*ifp->if_input)(ifp, m);
1679 	}
1680 
1681 	/* Update the receive pointer. */
1682 	sc->sc_rxptr = i;
1683 
1684 	return 1;
1685 }
1686 
1687 int
1688 emac_txde_intr(void *arg)
1689 {
1690 	struct emac_softc *sc = arg;
1691 
1692 	EMAC_EVCNT_INCR(&sc->sc_ev_txde);
1693 	aprint_error_dev(sc->sc_dev, "emac_txde_intr\n");
1694 	return 1;
1695 }
1696 
1697 int
1698 emac_rxde_intr(void *arg)
1699 {
1700 	struct emac_softc *sc = arg;
1701 	int i;
1702 
1703 	EMAC_EVCNT_INCR(&sc->sc_ev_rxde);
1704 	aprint_error_dev(sc->sc_dev, "emac_rxde_intr\n");
1705 	/*
1706 	 * XXX!
1707 	 * This is a bit drastic; we just drop all descriptors that aren't
1708 	 * "clean".  We should probably send any that are up the stack.
1709 	 */
1710 	for (i = 0; i < EMAC_NRXDESC; i++) {
1711 		EMAC_CDRXSYNC(sc, i,
1712 		    BUS_DMASYNC_POSTREAD | BUS_DMASYNC_POSTWRITE);
1713 
1714 		if (sc->sc_rxdescs[i].md_data_len != MCLBYTES)
1715 			EMAC_INIT_RXDESC(sc, i);
1716 	}
1717 
1718 	return 1;
1719 }
1720