xref: /freebsd/sys/dev/dwc/dwc1000_dma.c (revision 363b7c39fbad7c03f46e24bb4e435fad5cb56aa7)
1 /*-
2  * Copyright (c) 2014 Ruslan Bukin <br@bsdpad.com>
3  *
4  * This software was developed by SRI International and the University of
5  * Cambridge Computer Laboratory under DARPA/AFRL contract (FA8750-10-C-0237)
6  * ("CTSRD"), as part of the DARPA CRASH research programme.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #include <sys/cdefs.h>
31 #include <sys/param.h>
32 #include <sys/systm.h>
33 #include <sys/bus.h>
34 #include <sys/kernel.h>
35 #include <sys/lock.h>
36 #include <sys/malloc.h>
37 #include <sys/mbuf.h>
38 #include <sys/module.h>
39 #include <sys/mutex.h>
40 #include <sys/rman.h>
41 #include <sys/socket.h>
42 
43 #include <net/bpf.h>
44 #include <net/if.h>
45 #include <net/ethernet.h>
46 #include <net/if_dl.h>
47 #include <net/if_media.h>
48 #include <net/if_types.h>
49 #include <net/if_var.h>
50 
51 #include <machine/bus.h>
52 
53 #include <dev/extres/clk/clk.h>
54 #include <dev/extres/hwreset/hwreset.h>
55 
56 #include <dev/ofw/ofw_bus.h>
57 #include <dev/ofw/ofw_bus_subr.h>
58 
59 #include <dev/dwc/if_dwcvar.h>
60 #include <dev/dwc/dwc1000_reg.h>
61 #include <dev/dwc/dwc1000_dma.h>
62 
63 #define	WATCHDOG_TIMEOUT_SECS	5
64 #define	DMA_RESET_TIMEOUT	100
65 
66 /* TX descriptors - TDESC0 is almost unified */
67 #define	TDESC0_OWN		(1U << 31)
68 #define	TDESC0_IHE		(1U << 16)	/* IP Header Error */
69 #define	TDESC0_ES		(1U << 15)	/* Error Summary */
70 #define	TDESC0_JT		(1U << 14)	/* Jabber Timeout */
71 #define	TDESC0_FF		(1U << 13)	/* Frame Flushed */
72 #define	TDESC0_PCE		(1U << 12)	/* Payload Checksum Error */
73 #define	TDESC0_LOC		(1U << 11)	/* Loss of Carrier */
74 #define	TDESC0_NC		(1U << 10)	/* No Carrier */
75 #define	TDESC0_LC		(1U <<  9)	/* Late Collision */
76 #define	TDESC0_EC		(1U <<  8)	/* Excessive Collision */
77 #define	TDESC0_VF		(1U <<  7)	/* VLAN Frame */
78 #define	TDESC0_CC_MASK		0xf
79 #define	TDESC0_CC_SHIFT		3		/* Collision Count */
80 #define	TDESC0_ED		(1U <<  2)	/* Excessive Deferral */
81 #define	TDESC0_UF		(1U <<  1)	/* Underflow Error */
82 #define	TDESC0_DB		(1U <<  0)	/* Deferred Bit */
83 /* TX descriptors - TDESC0 extended format only */
84 #define	ETDESC0_IC		(1U << 30)	/* Interrupt on Completion */
85 #define	ETDESC0_LS		(1U << 29)	/* Last Segment */
86 #define	ETDESC0_FS		(1U << 28)	/* First Segment */
87 #define	ETDESC0_DC		(1U << 27)	/* Disable CRC */
88 #define	ETDESC0_DP		(1U << 26)	/* Disable Padding */
89 #define	ETDESC0_CIC_NONE	(0U << 22)	/* Checksum Insertion Control */
90 #define	ETDESC0_CIC_HDR		(1U << 22)
91 #define	ETDESC0_CIC_SEG 	(2U << 22)
92 #define	ETDESC0_CIC_FULL	(3U << 22)
93 #define	ETDESC0_TER		(1U << 21)	/* Transmit End of Ring */
94 #define	ETDESC0_TCH		(1U << 20)	/* Second Address Chained */
95 
96 /* TX descriptors - TDESC1 normal format */
97 #define	NTDESC1_IC		(1U << 31)	/* Interrupt on Completion */
98 #define	NTDESC1_LS		(1U << 30)	/* Last Segment */
99 #define	NTDESC1_FS		(1U << 29)	/* First Segment */
100 #define	NTDESC1_CIC_NONE	(0U << 27)	/* Checksum Insertion Control */
101 #define	NTDESC1_CIC_HDR		(1U << 27)
102 #define	NTDESC1_CIC_SEG 	(2U << 27)
103 #define	NTDESC1_CIC_FULL	(3U << 27)
104 #define	NTDESC1_DC		(1U << 26)	/* Disable CRC */
105 #define	NTDESC1_TER		(1U << 25)	/* Transmit End of Ring */
106 #define	NTDESC1_TCH		(1U << 24)	/* Second Address Chained */
107 /* TX descriptors - TDESC1 extended format */
108 #define	ETDESC1_DP		(1U << 23)	/* Disable Padding */
109 #define	ETDESC1_TBS2_MASK	0x7ff
110 #define	ETDESC1_TBS2_SHIFT	11		/* Receive Buffer 2 Size */
111 #define	ETDESC1_TBS1_MASK	0x7ff
112 #define	ETDESC1_TBS1_SHIFT	0		/* Receive Buffer 1 Size */
113 
114 /* RX descriptor - RDESC0 is unified */
115 #define	RDESC0_OWN		(1U << 31)
116 #define	RDESC0_AFM		(1U << 30)	/* Dest. Address Filter Fail */
117 #define	RDESC0_FL_MASK		0x3fff
118 #define	RDESC0_FL_SHIFT		16		/* Frame Length */
119 #define	RDESC0_ES		(1U << 15)	/* Error Summary */
120 #define	RDESC0_DE		(1U << 14)	/* Descriptor Error */
121 #define	RDESC0_SAF		(1U << 13)	/* Source Address Filter Fail */
122 #define	RDESC0_LE		(1U << 12)	/* Length Error */
123 #define	RDESC0_OE		(1U << 11)	/* Overflow Error */
124 #define	RDESC0_VLAN		(1U << 10)	/* VLAN Tag */
125 #define	RDESC0_FS		(1U <<  9)	/* First Descriptor */
126 #define	RDESC0_LS		(1U <<  8)	/* Last Descriptor */
127 #define	RDESC0_ICE		(1U <<  7)	/* IPC Checksum Error */
128 #define	RDESC0_LC		(1U <<  6)	/* Late Collision */
129 #define	RDESC0_FT		(1U <<  5)	/* Frame Type */
130 #define	RDESC0_RWT		(1U <<  4)	/* Receive Watchdog Timeout */
131 #define	RDESC0_RE		(1U <<  3)	/* Receive Error */
132 #define	RDESC0_DBE		(1U <<  2)	/* Dribble Bit Error */
133 #define	RDESC0_CE		(1U <<  1)	/* CRC Error */
134 #define	RDESC0_PCE		(1U <<  0)	/* Payload Checksum Error */
135 #define	RDESC0_RXMA		(1U <<  0)	/* Rx MAC Address */
136 
137 /* RX descriptors - RDESC1 normal format */
138 #define	NRDESC1_DIC		(1U << 31)	/* Disable Intr on Completion */
139 #define	NRDESC1_RER		(1U << 25)	/* Receive End of Ring */
140 #define	NRDESC1_RCH		(1U << 24)	/* Second Address Chained */
141 #define	NRDESC1_RBS2_MASK	0x7ff
142 #define	NRDESC1_RBS2_SHIFT	11		/* Receive Buffer 2 Size */
143 #define	NRDESC1_RBS1_MASK	0x7ff
144 #define	NRDESC1_RBS1_SHIFT	0		/* Receive Buffer 1 Size */
145 
146 /* RX descriptors - RDESC1 enhanced format */
147 #define	ERDESC1_DIC		(1U << 31)	/* Disable Intr on Completion */
148 #define	ERDESC1_RBS2_MASK	0x7ffff
149 #define	ERDESC1_RBS2_SHIFT	16		/* Receive Buffer 2 Size */
150 #define	ERDESC1_RER		(1U << 15)	/* Receive End of Ring */
151 #define	ERDESC1_RCH		(1U << 14)	/* Second Address Chained */
152 #define	ERDESC1_RBS1_MASK	0x7ffff
153 #define	ERDESC1_RBS1_SHIFT	0		/* Receive Buffer 1 Size */
154 
155 /*
156  * The hardware imposes alignment restrictions on various objects involved in
157  * DMA transfers.  These values are expressed in bytes (not bits).
158  */
159 #define	DWC_DESC_RING_ALIGN	2048
160 
161 static inline uint32_t
162 next_txidx(struct dwc_softc *sc, uint32_t curidx)
163 {
164 
165 	return ((curidx + 1) % TX_DESC_COUNT);
166 }
167 
168 static inline uint32_t
169 next_rxidx(struct dwc_softc *sc, uint32_t curidx)
170 {
171 
172 	return ((curidx + 1) % RX_DESC_COUNT);
173 }
174 
175 static void
176 dwc_get1paddr(void *arg, bus_dma_segment_t *segs, int nsegs, int error)
177 {
178 
179 	if (error != 0)
180 		return;
181 	*(bus_addr_t *)arg = segs[0].ds_addr;
182 }
183 
184 inline static void
185 dwc_set_owner(struct dwc_softc *sc, int idx)
186 {
187 	wmb();
188 	sc->txdesc_ring[idx].desc0 |= TDESC0_OWN;
189 	wmb();
190 }
191 
192 inline static void
193 dwc_setup_txdesc(struct dwc_softc *sc, int idx, bus_addr_t paddr,
194   uint32_t len, uint32_t flags, bool first, bool last)
195 {
196 	uint32_t desc0, desc1;
197 
198 	/* Addr/len 0 means we're clearing the descriptor after xmit done. */
199 	if (paddr == 0 || len == 0) {
200 		desc0 = 0;
201 		desc1 = 0;
202 		--sc->tx_desccount;
203 	} else {
204 		if (sc->mactype != DWC_GMAC_EXT_DESC) {
205 			desc0 = 0;
206 			desc1 = NTDESC1_TCH | len | flags;
207 			if (first)
208 				desc1 |=  NTDESC1_FS;
209 			if (last)
210 				desc1 |= NTDESC1_LS | NTDESC1_IC;
211 		} else {
212 			desc0 = ETDESC0_TCH | flags;
213 			if (first)
214 				desc0 |= ETDESC0_FS;
215 			if (last)
216 				desc0 |= ETDESC0_LS | ETDESC0_IC;
217 			desc1 = len;
218 		}
219 		++sc->tx_desccount;
220 	}
221 
222 	sc->txdesc_ring[idx].addr1 = (uint32_t)(paddr);
223 	sc->txdesc_ring[idx].desc0 = desc0;
224 	sc->txdesc_ring[idx].desc1 = desc1;
225 }
226 
227 inline static uint32_t
228 dwc_setup_rxdesc(struct dwc_softc *sc, int idx, bus_addr_t paddr)
229 {
230 	uint32_t nidx;
231 
232 	sc->rxdesc_ring[idx].addr1 = (uint32_t)paddr;
233 	nidx = next_rxidx(sc, idx);
234 	sc->rxdesc_ring[idx].addr2 = sc->rxdesc_ring_paddr +
235 	    (nidx * sizeof(struct dwc_hwdesc));
236 	if (sc->mactype != DWC_GMAC_EXT_DESC)
237 		sc->rxdesc_ring[idx].desc1 = NRDESC1_RCH |
238 		    MIN(MCLBYTES, NRDESC1_RBS1_MASK);
239 	else
240 		sc->rxdesc_ring[idx].desc1 = ERDESC1_RCH |
241 		    MIN(MCLBYTES, ERDESC1_RBS1_MASK);
242 
243 	wmb();
244 	sc->rxdesc_ring[idx].desc0 = RDESC0_OWN;
245 	wmb();
246 	return (nidx);
247 }
248 
249 int
250 dma1000_setup_txbuf(struct dwc_softc *sc, int idx, struct mbuf **mp)
251 {
252 	struct bus_dma_segment segs[TX_MAP_MAX_SEGS];
253 	int error, nsegs;
254 	struct mbuf * m;
255 	uint32_t flags = 0;
256 	int i;
257 	int first, last;
258 
259 	error = bus_dmamap_load_mbuf_sg(sc->txbuf_tag, sc->txbuf_map[idx].map,
260 	    *mp, segs, &nsegs, 0);
261 	if (error == EFBIG) {
262 		/*
263 		 * The map may be partially mapped from the first call.
264 		 * Make sure to reset it.
265 		 */
266 		bus_dmamap_unload(sc->txbuf_tag, sc->txbuf_map[idx].map);
267 		if ((m = m_defrag(*mp, M_NOWAIT)) == NULL)
268 			return (ENOMEM);
269 		*mp = m;
270 		error = bus_dmamap_load_mbuf_sg(sc->txbuf_tag, sc->txbuf_map[idx].map,
271 		    *mp, segs, &nsegs, 0);
272 	}
273 	if (error != 0)
274 		return (ENOMEM);
275 
276 	if (sc->tx_desccount + nsegs > TX_DESC_COUNT) {
277 		bus_dmamap_unload(sc->txbuf_tag, sc->txbuf_map[idx].map);
278 		return (ENOMEM);
279 	}
280 
281 	m = *mp;
282 
283 	if ((m->m_pkthdr.csum_flags & CSUM_IP) != 0) {
284 		if ((m->m_pkthdr.csum_flags & (CSUM_TCP|CSUM_UDP)) != 0) {
285 			if (sc->mactype != DWC_GMAC_EXT_DESC)
286 				flags = NTDESC1_CIC_FULL;
287 			else
288 				flags = ETDESC0_CIC_FULL;
289 		} else {
290 			if (sc->mactype != DWC_GMAC_EXT_DESC)
291 				flags = NTDESC1_CIC_HDR;
292 			else
293 				flags = ETDESC0_CIC_HDR;
294 		}
295 	}
296 
297 	bus_dmamap_sync(sc->txbuf_tag, sc->txbuf_map[idx].map,
298 	    BUS_DMASYNC_PREWRITE);
299 
300 	sc->txbuf_map[idx].mbuf = m;
301 
302 	first = sc->tx_desc_head;
303 	for (i = 0; i < nsegs; i++) {
304 		dwc_setup_txdesc(sc, sc->tx_desc_head,
305 		    segs[i].ds_addr, segs[i].ds_len,
306 		    (i == 0) ? flags : 0, /* only first desc needs flags */
307 		    (i == 0),
308 		    (i == nsegs - 1));
309 		if (i > 0)
310 			dwc_set_owner(sc, sc->tx_desc_head);
311 		last = sc->tx_desc_head;
312 		sc->tx_desc_head = next_txidx(sc, sc->tx_desc_head);
313 	}
314 
315 	sc->txbuf_map[idx].last_desc_idx = last;
316 
317 	dwc_set_owner(sc, first);
318 
319 	return (0);
320 }
321 
322 static int
323 dma1000_setup_rxbuf(struct dwc_softc *sc, int idx, struct mbuf *m)
324 {
325 	struct bus_dma_segment seg;
326 	int error, nsegs;
327 
328 	m_adj(m, ETHER_ALIGN);
329 
330 	error = bus_dmamap_load_mbuf_sg(sc->rxbuf_tag, sc->rxbuf_map[idx].map,
331 	    m, &seg, &nsegs, 0);
332 	if (error != 0)
333 		return (error);
334 
335 	KASSERT(nsegs == 1, ("%s: %d segments returned!", __func__, nsegs));
336 
337 	bus_dmamap_sync(sc->rxbuf_tag, sc->rxbuf_map[idx].map,
338 	    BUS_DMASYNC_PREREAD);
339 
340 	sc->rxbuf_map[idx].mbuf = m;
341 	dwc_setup_rxdesc(sc, idx, seg.ds_addr);
342 
343 	return (0);
344 }
345 
346 static struct mbuf *
347 dwc_alloc_mbufcl(struct dwc_softc *sc)
348 {
349 	struct mbuf *m;
350 
351 	m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
352 	if (m != NULL)
353 		m->m_pkthdr.len = m->m_len = m->m_ext.ext_size;
354 
355 	return (m);
356 }
357 
358 static struct mbuf *
359 dwc_rxfinish_one(struct dwc_softc *sc, struct dwc_hwdesc *desc,
360     struct dwc_bufmap *map)
361 {
362 	if_t ifp;
363 	struct mbuf *m, *m0;
364 	int len;
365 	uint32_t rdesc0;
366 
367 	m = map->mbuf;
368 	ifp = sc->ifp;
369 	rdesc0 = desc ->desc0;
370 
371 	if ((rdesc0 & (RDESC0_FS | RDESC0_LS)) !=
372 		    (RDESC0_FS | RDESC0_LS)) {
373 		/*
374 		 * Something very wrong happens. The whole packet should be
375 		 * recevied in one descriptr. Report problem.
376 		 */
377 		device_printf(sc->dev,
378 		    "%s: RX descriptor without FIRST and LAST bit set: 0x%08X",
379 		    __func__, rdesc0);
380 		return (NULL);
381 	}
382 
383 	len = (rdesc0 >> RDESC0_FL_SHIFT) & RDESC0_FL_MASK;
384 	if (len < 64) {
385 		/*
386 		 * Lenght is invalid, recycle old mbuf
387 		 * Probably impossible case
388 		 */
389 		return (NULL);
390 	}
391 
392 	/* Allocate new buffer */
393 	m0 = dwc_alloc_mbufcl(sc);
394 	if (m0 == NULL) {
395 		/* no new mbuf available, recycle old */
396 		if_inc_counter(sc->ifp, IFCOUNTER_IQDROPS, 1);
397 		return (NULL);
398 	}
399 	/* Do dmasync for newly received packet */
400 	bus_dmamap_sync(sc->rxbuf_tag, map->map, BUS_DMASYNC_POSTREAD);
401 	bus_dmamap_unload(sc->rxbuf_tag, map->map);
402 
403 	/* Received packet is valid, process it */
404 	m->m_pkthdr.rcvif = ifp;
405 	m->m_pkthdr.len = len;
406 	m->m_len = len;
407 	if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1);
408 
409 	if ((if_getcapenable(ifp) & IFCAP_RXCSUM) != 0 &&
410 	  (rdesc0 & RDESC0_FT) != 0) {
411 		m->m_pkthdr.csum_flags = CSUM_IP_CHECKED;
412 		if ((rdesc0 & RDESC0_ICE) == 0)
413 			m->m_pkthdr.csum_flags |= CSUM_IP_VALID;
414 		if ((rdesc0 & RDESC0_PCE) == 0) {
415 			m->m_pkthdr.csum_flags |=
416 				CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
417 			m->m_pkthdr.csum_data = 0xffff;
418 		}
419 	}
420 
421 	/* Remove trailing FCS */
422 	m_adj(m, -ETHER_CRC_LEN);
423 
424 	DWC_UNLOCK(sc);
425 	if_input(ifp, m);
426 	DWC_LOCK(sc);
427 	return (m0);
428 }
429 
430 void
431 dma1000_txfinish_locked(struct dwc_softc *sc)
432 {
433 	struct dwc_bufmap *bmap;
434 	struct dwc_hwdesc *desc;
435 	if_t ifp;
436 	int idx, last_idx;
437 	bool map_finished;
438 
439 	DWC_ASSERT_LOCKED(sc);
440 
441 	ifp = sc->ifp;
442 	/* check if all descriptors of the map are done */
443 	while (sc->tx_map_tail != sc->tx_map_head) {
444 		map_finished = true;
445 		bmap = &sc->txbuf_map[sc->tx_map_tail];
446 		idx = sc->tx_desc_tail;
447 		last_idx = next_txidx(sc, bmap->last_desc_idx);
448 		while (idx != last_idx) {
449 			desc = &sc->txdesc_ring[idx];
450 			if ((desc->desc0 & TDESC0_OWN) != 0) {
451 				map_finished = false;
452 				break;
453 			}
454 			idx = next_txidx(sc, idx);
455 		}
456 
457 		if (!map_finished)
458 			break;
459 		bus_dmamap_sync(sc->txbuf_tag, bmap->map,
460 		    BUS_DMASYNC_POSTWRITE);
461 		bus_dmamap_unload(sc->txbuf_tag, bmap->map);
462 		m_freem(bmap->mbuf);
463 		bmap->mbuf = NULL;
464 		sc->tx_mapcount--;
465 		while (sc->tx_desc_tail != last_idx) {
466 			dwc_setup_txdesc(sc, sc->tx_desc_tail, 0, 0, 0, false, false);
467 			sc->tx_desc_tail = next_txidx(sc, sc->tx_desc_tail);
468 		}
469 		sc->tx_map_tail = next_txidx(sc, sc->tx_map_tail);
470 		if_setdrvflagbits(ifp, 0, IFF_DRV_OACTIVE);
471 		if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
472 	}
473 
474 	/* If there are no buffers outstanding, muzzle the watchdog. */
475 	if (sc->tx_desc_tail == sc->tx_desc_head) {
476 		sc->tx_watchdog_count = 0;
477 	}
478 }
479 
480 void
481 dma1000_txstart(struct dwc_softc *sc)
482 {
483 	int enqueued;
484 	struct mbuf *m;
485 
486 	enqueued = 0;
487 
488 	for (;;) {
489 		if (sc->tx_desccount > (TX_DESC_COUNT - TX_MAP_MAX_SEGS  + 1)) {
490 			if_setdrvflagbits(sc->ifp, IFF_DRV_OACTIVE, 0);
491 			break;
492 		}
493 
494 		if (sc->tx_mapcount == (TX_MAP_COUNT - 1)) {
495 			if_setdrvflagbits(sc->ifp, IFF_DRV_OACTIVE, 0);
496 			break;
497 		}
498 
499 		m = if_dequeue(sc->ifp);
500 		if (m == NULL)
501 			break;
502 		if (dma1000_setup_txbuf(sc, sc->tx_map_head, &m) != 0) {
503 			if_sendq_prepend(sc->ifp, m);
504 			if_setdrvflagbits(sc->ifp, IFF_DRV_OACTIVE, 0);
505 			break;
506 		}
507 		bpf_mtap_if(sc->ifp, m);
508 		sc->tx_map_head = next_txidx(sc, sc->tx_map_head);
509 		sc->tx_mapcount++;
510 		++enqueued;
511 	}
512 
513 	if (enqueued != 0) {
514 		WRITE4(sc, TRANSMIT_POLL_DEMAND, 0x1);
515 		sc->tx_watchdog_count = WATCHDOG_TIMEOUT_SECS;
516 	}
517 }
518 
519 void
520 dma1000_rxfinish_locked(struct dwc_softc *sc)
521 {
522 	struct mbuf *m;
523 	int error, idx;
524 	struct dwc_hwdesc *desc;
525 
526 	DWC_ASSERT_LOCKED(sc);
527 	for (;;) {
528 		idx = sc->rx_idx;
529 		desc = sc->rxdesc_ring + idx;
530 		if ((desc->desc0 & RDESC0_OWN) != 0)
531 			break;
532 
533 		m = dwc_rxfinish_one(sc, desc, sc->rxbuf_map + idx);
534 		if (m == NULL) {
535 			wmb();
536 			desc->desc0 = RDESC0_OWN;
537 			wmb();
538 		} else {
539 			/* We cannot create hole in RX ring */
540 			error = dma1000_setup_rxbuf(sc, idx, m);
541 			if (error != 0)
542 				panic("dma1000_setup_rxbuf failed:  error %d\n",
543 				    error);
544 
545 		}
546 		sc->rx_idx = next_rxidx(sc, sc->rx_idx);
547 	}
548 }
549 
550 /*
551  * Start the DMA controller
552  */
553 void
554 dma1000_start(struct dwc_softc *sc)
555 {
556 	uint32_t reg;
557 
558 	DWC_ASSERT_LOCKED(sc);
559 
560 	/* Initializa DMA and enable transmitters */
561 	reg = READ4(sc, OPERATION_MODE);
562 	reg |= (MODE_TSF | MODE_OSF | MODE_FUF);
563 	reg &= ~(MODE_RSF);
564 	reg |= (MODE_RTC_LEV32 << MODE_RTC_SHIFT);
565 	WRITE4(sc, OPERATION_MODE, reg);
566 
567 	WRITE4(sc, INTERRUPT_ENABLE, INT_EN_DEFAULT);
568 
569 	/* Start DMA */
570 	reg = READ4(sc, OPERATION_MODE);
571 	reg |= (MODE_ST | MODE_SR);
572 	WRITE4(sc, OPERATION_MODE, reg);
573 }
574 
575 /*
576  * Stop the DMA controller
577  */
578 void
579 dma1000_stop(struct dwc_softc *sc)
580 {
581 	uint32_t reg;
582 
583 	DWC_ASSERT_LOCKED(sc);
584 
585 	/* Stop DMA TX */
586 	reg = READ4(sc, OPERATION_MODE);
587 	reg &= ~(MODE_ST);
588 	WRITE4(sc, OPERATION_MODE, reg);
589 
590 	/* Flush TX */
591 	reg = READ4(sc, OPERATION_MODE);
592 	reg |= (MODE_FTF);
593 	WRITE4(sc, OPERATION_MODE, reg);
594 
595 	/* Stop DMA RX */
596 	reg = READ4(sc, OPERATION_MODE);
597 	reg &= ~(MODE_SR);
598 	WRITE4(sc, OPERATION_MODE, reg);
599 }
600 
601 int
602 dma1000_reset(struct dwc_softc *sc)
603 {
604 	uint32_t reg;
605 	int i;
606 
607 	reg = READ4(sc, BUS_MODE);
608 	reg |= (BUS_MODE_SWR);
609 	WRITE4(sc, BUS_MODE, reg);
610 
611 	for (i = 0; i < DMA_RESET_TIMEOUT; i++) {
612 		if ((READ4(sc, BUS_MODE) & BUS_MODE_SWR) == 0)
613 			break;
614 		DELAY(10);
615 	}
616 	if (i >= DMA_RESET_TIMEOUT) {
617 		return (ENXIO);
618 	}
619 
620 	return (0);
621 }
622 
623 /*
624  * Create the bus_dma resources
625  */
626 int
627 dma1000_init(struct dwc_softc *sc)
628 {
629 	struct mbuf *m;
630 	uint32_t reg;
631 	int error;
632 	int nidx;
633 	int idx;
634 
635 	/*
636 	 * DMA must be stop while changing descriptor list addresses.
637 	 */
638 	reg = READ4(sc, OPERATION_MODE);
639 	reg &= ~(MODE_ST | MODE_SR);
640 	WRITE4(sc, OPERATION_MODE, reg);
641 
642 	/*
643 	 * Set up TX descriptor ring, descriptors, and dma maps.
644 	 */
645 	error = bus_dma_tag_create(
646 	    bus_get_dma_tag(sc->dev),	/* Parent tag. */
647 	    DWC_DESC_RING_ALIGN, 0,	/* alignment, boundary */
648 	    BUS_SPACE_MAXADDR_32BIT,	/* lowaddr */
649 	    BUS_SPACE_MAXADDR,		/* highaddr */
650 	    NULL, NULL,			/* filter, filterarg */
651 	    TX_DESC_SIZE, 1, 		/* maxsize, nsegments */
652 	    TX_DESC_SIZE,		/* maxsegsize */
653 	    0,				/* flags */
654 	    NULL, NULL,			/* lockfunc, lockarg */
655 	    &sc->txdesc_tag);
656 	if (error != 0) {
657 		device_printf(sc->dev,
658 		    "could not create TX ring DMA tag.\n");
659 		goto out;
660 	}
661 
662 	error = bus_dmamem_alloc(sc->txdesc_tag, (void**)&sc->txdesc_ring,
663 	    BUS_DMA_COHERENT | BUS_DMA_WAITOK | BUS_DMA_ZERO,
664 	    &sc->txdesc_map);
665 	if (error != 0) {
666 		device_printf(sc->dev,
667 		    "could not allocate TX descriptor ring.\n");
668 		goto out;
669 	}
670 
671 	error = bus_dmamap_load(sc->txdesc_tag, sc->txdesc_map,
672 	    sc->txdesc_ring, TX_DESC_SIZE, dwc_get1paddr,
673 	    &sc->txdesc_ring_paddr, 0);
674 	if (error != 0) {
675 		device_printf(sc->dev,
676 		    "could not load TX descriptor ring map.\n");
677 		goto out;
678 	}
679 
680 	for (idx = 0; idx < TX_DESC_COUNT; idx++) {
681 		nidx = next_txidx(sc, idx);
682 		sc->txdesc_ring[idx].addr2 = sc->txdesc_ring_paddr +
683 		    (nidx * sizeof(struct dwc_hwdesc));
684 	}
685 
686 	error = bus_dma_tag_create(
687 	    bus_get_dma_tag(sc->dev),	/* Parent tag. */
688 	    1, 0,			/* alignment, boundary */
689 	    BUS_SPACE_MAXADDR_32BIT,	/* lowaddr */
690 	    BUS_SPACE_MAXADDR,		/* highaddr */
691 	    NULL, NULL,			/* filter, filterarg */
692 	    MCLBYTES*TX_MAP_MAX_SEGS,	/* maxsize */
693 	    TX_MAP_MAX_SEGS,		/* nsegments */
694 	    MCLBYTES,			/* maxsegsize */
695 	    0,				/* flags */
696 	    NULL, NULL,			/* lockfunc, lockarg */
697 	    &sc->txbuf_tag);
698 	if (error != 0) {
699 		device_printf(sc->dev,
700 		    "could not create TX ring DMA tag.\n");
701 		goto out;
702 	}
703 
704 	for (idx = 0; idx < TX_MAP_COUNT; idx++) {
705 		error = bus_dmamap_create(sc->txbuf_tag, BUS_DMA_COHERENT,
706 		    &sc->txbuf_map[idx].map);
707 		if (error != 0) {
708 			device_printf(sc->dev,
709 			    "could not create TX buffer DMA map.\n");
710 			goto out;
711 		}
712 	}
713 
714 	for (idx = 0; idx < TX_DESC_COUNT; idx++)
715 		dwc_setup_txdesc(sc, idx, 0, 0, 0, false, false);
716 
717 	WRITE4(sc, TX_DESCR_LIST_ADDR, sc->txdesc_ring_paddr);
718 
719 	/*
720 	 * Set up RX descriptor ring, descriptors, dma maps, and mbufs.
721 	 */
722 	error = bus_dma_tag_create(
723 	    bus_get_dma_tag(sc->dev),	/* Parent tag. */
724 	    DWC_DESC_RING_ALIGN, 0,	/* alignment, boundary */
725 	    BUS_SPACE_MAXADDR_32BIT,	/* lowaddr */
726 	    BUS_SPACE_MAXADDR,		/* highaddr */
727 	    NULL, NULL,			/* filter, filterarg */
728 	    RX_DESC_SIZE, 1, 		/* maxsize, nsegments */
729 	    RX_DESC_SIZE,		/* maxsegsize */
730 	    0,				/* flags */
731 	    NULL, NULL,			/* lockfunc, lockarg */
732 	    &sc->rxdesc_tag);
733 	if (error != 0) {
734 		device_printf(sc->dev,
735 		    "could not create RX ring DMA tag.\n");
736 		goto out;
737 	}
738 
739 	error = bus_dmamem_alloc(sc->rxdesc_tag, (void **)&sc->rxdesc_ring,
740 	    BUS_DMA_COHERENT | BUS_DMA_WAITOK | BUS_DMA_ZERO,
741 	    &sc->rxdesc_map);
742 	if (error != 0) {
743 		device_printf(sc->dev,
744 		    "could not allocate RX descriptor ring.\n");
745 		goto out;
746 	}
747 
748 	error = bus_dmamap_load(sc->rxdesc_tag, sc->rxdesc_map,
749 	    sc->rxdesc_ring, RX_DESC_SIZE, dwc_get1paddr,
750 	    &sc->rxdesc_ring_paddr, 0);
751 	if (error != 0) {
752 		device_printf(sc->dev,
753 		    "could not load RX descriptor ring map.\n");
754 		goto out;
755 	}
756 
757 	error = bus_dma_tag_create(
758 	    bus_get_dma_tag(sc->dev),	/* Parent tag. */
759 	    1, 0,			/* alignment, boundary */
760 	    BUS_SPACE_MAXADDR_32BIT,	/* lowaddr */
761 	    BUS_SPACE_MAXADDR,		/* highaddr */
762 	    NULL, NULL,			/* filter, filterarg */
763 	    MCLBYTES, 1, 		/* maxsize, nsegments */
764 	    MCLBYTES,			/* maxsegsize */
765 	    0,				/* flags */
766 	    NULL, NULL,			/* lockfunc, lockarg */
767 	    &sc->rxbuf_tag);
768 	if (error != 0) {
769 		device_printf(sc->dev,
770 		    "could not create RX buf DMA tag.\n");
771 		goto out;
772 	}
773 
774 	for (idx = 0; idx < RX_DESC_COUNT; idx++) {
775 		error = bus_dmamap_create(sc->rxbuf_tag, BUS_DMA_COHERENT,
776 		    &sc->rxbuf_map[idx].map);
777 		if (error != 0) {
778 			device_printf(sc->dev,
779 			    "could not create RX buffer DMA map.\n");
780 			goto out;
781 		}
782 		if ((m = dwc_alloc_mbufcl(sc)) == NULL) {
783 			device_printf(sc->dev, "Could not alloc mbuf\n");
784 			error = ENOMEM;
785 			goto out;
786 		}
787 		if ((error = dma1000_setup_rxbuf(sc, idx, m)) != 0) {
788 			device_printf(sc->dev,
789 			    "could not create new RX buffer.\n");
790 			goto out;
791 		}
792 	}
793 	WRITE4(sc, RX_DESCR_LIST_ADDR, sc->rxdesc_ring_paddr);
794 
795 out:
796 	if (error != 0)
797 		return (ENXIO);
798 
799 	return (0);
800 }
801 
802 /*
803  * Free the bus_dma resources
804  */
805 void
806 dma1000_free(struct dwc_softc *sc)
807 {
808 	bus_dmamap_t map;
809 	int idx;
810 
811 	/* Clean up RX DMA resources and free mbufs. */
812 	for (idx = 0; idx < RX_DESC_COUNT; ++idx) {
813 		if ((map = sc->rxbuf_map[idx].map) != NULL) {
814 			bus_dmamap_unload(sc->rxbuf_tag, map);
815 			bus_dmamap_destroy(sc->rxbuf_tag, map);
816 			m_freem(sc->rxbuf_map[idx].mbuf);
817 		}
818 	}
819 	if (sc->rxbuf_tag != NULL)
820 		bus_dma_tag_destroy(sc->rxbuf_tag);
821 	if (sc->rxdesc_map != NULL) {
822 		bus_dmamap_unload(sc->rxdesc_tag, sc->rxdesc_map);
823 		bus_dmamem_free(sc->rxdesc_tag, sc->rxdesc_ring,
824 		    sc->rxdesc_map);
825 	}
826 	if (sc->rxdesc_tag != NULL)
827 		bus_dma_tag_destroy(sc->rxdesc_tag);
828 
829 	/* Clean up TX DMA resources. */
830 	for (idx = 0; idx < TX_DESC_COUNT; ++idx) {
831 		if ((map = sc->txbuf_map[idx].map) != NULL) {
832 			/* TX maps are already unloaded. */
833 			bus_dmamap_destroy(sc->txbuf_tag, map);
834 		}
835 	}
836 	if (sc->txbuf_tag != NULL)
837 		bus_dma_tag_destroy(sc->txbuf_tag);
838 	if (sc->txdesc_map != NULL) {
839 		bus_dmamap_unload(sc->txdesc_tag, sc->txdesc_map);
840 		bus_dmamem_free(sc->txdesc_tag, sc->txdesc_ring,
841 		    sc->txdesc_map);
842 	}
843 	if (sc->txdesc_tag != NULL)
844 		bus_dma_tag_destroy(sc->txdesc_tag);
845 }
846 
847 /*
848  * Interrupt function
849  */
850 
851 int
852 dma1000_intr(struct dwc_softc *sc)
853 {
854 	uint32_t reg;
855 	int rv;
856 
857 	DWC_ASSERT_LOCKED(sc);
858 
859 	rv = 0;
860 	reg = READ4(sc, DMA_STATUS);
861 	if (reg & DMA_STATUS_NIS) {
862 		if (reg & DMA_STATUS_RI)
863 			dma1000_rxfinish_locked(sc);
864 
865 		if (reg & DMA_STATUS_TI) {
866 			dma1000_txfinish_locked(sc);
867 			dma1000_txstart(sc);
868 		}
869 	}
870 
871 	if (reg & DMA_STATUS_AIS) {
872 		if (reg & DMA_STATUS_FBI) {
873 			/* Fatal bus error */
874 			rv = EIO;
875 		}
876 	}
877 
878 	WRITE4(sc, DMA_STATUS, reg & DMA_STATUS_INTR_MASK);
879 	return (rv);
880 }
881