xref: /linux/drivers/net/wireless/broadcom/b43legacy/dma.c (revision 4a95857a875e887cc958c92fe9d2cde6184d2ec0)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 
4   Broadcom B43legacy wireless driver
5 
6   DMA ringbuffer and descriptor allocation/management
7 
8   Copyright (c) 2005, 2006 Michael Buesch <m@bues.ch>
9 
10   Some code in this file is derived from the b44.c driver
11   Copyright (C) 2002 David S. Miller
12   Copyright (C) Pekka Pietikainen
13 
14 
15 */
16 
17 #include "b43legacy.h"
18 #include "dma.h"
19 #include "main.h"
20 #include "debugfs.h"
21 #include "xmit.h"
22 
23 #include <linux/dma-mapping.h>
24 #include <linux/pci.h>
25 #include <linux/delay.h>
26 #include <linux/skbuff.h>
27 #include <linux/slab.h>
28 #include <net/dst.h>
29 
30 /* 32bit DMA ops. */
31 static
32 struct b43legacy_dmadesc32 *op32_idx2desc(struct b43legacy_dmaring *ring,
33 					  int slot,
34 					  struct b43legacy_dmadesc_meta **meta)
35 {
36 	struct b43legacy_dmadesc32 *desc;
37 
38 	*meta = &(ring->meta[slot]);
39 	desc = ring->descbase;
40 	desc = &(desc[slot]);
41 
42 	return desc;
43 }
44 
45 static void op32_fill_descriptor(struct b43legacy_dmaring *ring,
46 				 struct b43legacy_dmadesc32 *desc,
47 				 dma_addr_t dmaaddr, u16 bufsize,
48 				 int start, int end, int irq)
49 {
50 	struct b43legacy_dmadesc32 *descbase = ring->descbase;
51 	int slot;
52 	u32 ctl;
53 	u32 addr;
54 	u32 addrext;
55 
56 	slot = (int)(desc - descbase);
57 	B43legacy_WARN_ON(!(slot >= 0 && slot < ring->nr_slots));
58 
59 	addr = (u32)(dmaaddr & ~SSB_DMA_TRANSLATION_MASK);
60 	addrext = (u32)(dmaaddr & SSB_DMA_TRANSLATION_MASK)
61 		   >> SSB_DMA_TRANSLATION_SHIFT;
62 	addr |= ring->dev->dma.translation;
63 	ctl = (bufsize - ring->frameoffset)
64 	      & B43legacy_DMA32_DCTL_BYTECNT;
65 	if (slot == ring->nr_slots - 1)
66 		ctl |= B43legacy_DMA32_DCTL_DTABLEEND;
67 	if (start)
68 		ctl |= B43legacy_DMA32_DCTL_FRAMESTART;
69 	if (end)
70 		ctl |= B43legacy_DMA32_DCTL_FRAMEEND;
71 	if (irq)
72 		ctl |= B43legacy_DMA32_DCTL_IRQ;
73 	ctl |= (addrext << B43legacy_DMA32_DCTL_ADDREXT_SHIFT)
74 	       & B43legacy_DMA32_DCTL_ADDREXT_MASK;
75 
76 	desc->control = cpu_to_le32(ctl);
77 	desc->address = cpu_to_le32(addr);
78 }
79 
80 static void op32_poke_tx(struct b43legacy_dmaring *ring, int slot)
81 {
82 	b43legacy_dma_write(ring, B43legacy_DMA32_TXINDEX,
83 			    (u32)(slot * sizeof(struct b43legacy_dmadesc32)));
84 }
85 
86 static void op32_tx_suspend(struct b43legacy_dmaring *ring)
87 {
88 	b43legacy_dma_write(ring, B43legacy_DMA32_TXCTL,
89 			    b43legacy_dma_read(ring, B43legacy_DMA32_TXCTL)
90 			    | B43legacy_DMA32_TXSUSPEND);
91 }
92 
93 static void op32_tx_resume(struct b43legacy_dmaring *ring)
94 {
95 	b43legacy_dma_write(ring, B43legacy_DMA32_TXCTL,
96 			    b43legacy_dma_read(ring, B43legacy_DMA32_TXCTL)
97 			    & ~B43legacy_DMA32_TXSUSPEND);
98 }
99 
100 static int op32_get_current_rxslot(struct b43legacy_dmaring *ring)
101 {
102 	u32 val;
103 
104 	val = b43legacy_dma_read(ring, B43legacy_DMA32_RXSTATUS);
105 	val &= B43legacy_DMA32_RXDPTR;
106 
107 	return (val / sizeof(struct b43legacy_dmadesc32));
108 }
109 
110 static void op32_set_current_rxslot(struct b43legacy_dmaring *ring,
111 				    int slot)
112 {
113 	b43legacy_dma_write(ring, B43legacy_DMA32_RXINDEX,
114 			    (u32)(slot * sizeof(struct b43legacy_dmadesc32)));
115 }
116 
117 static inline int free_slots(struct b43legacy_dmaring *ring)
118 {
119 	return (ring->nr_slots - ring->used_slots);
120 }
121 
122 static inline int next_slot(struct b43legacy_dmaring *ring, int slot)
123 {
124 	B43legacy_WARN_ON(!(slot >= -1 && slot <= ring->nr_slots - 1));
125 	if (slot == ring->nr_slots - 1)
126 		return 0;
127 	return slot + 1;
128 }
129 
130 static inline int prev_slot(struct b43legacy_dmaring *ring, int slot)
131 {
132 	B43legacy_WARN_ON(!(slot >= 0 && slot <= ring->nr_slots - 1));
133 	if (slot == 0)
134 		return ring->nr_slots - 1;
135 	return slot - 1;
136 }
137 
138 #ifdef CONFIG_B43LEGACY_DEBUG
139 static void update_max_used_slots(struct b43legacy_dmaring *ring,
140 				  int current_used_slots)
141 {
142 	if (current_used_slots <= ring->max_used_slots)
143 		return;
144 	ring->max_used_slots = current_used_slots;
145 	if (b43legacy_debug(ring->dev, B43legacy_DBG_DMAVERBOSE))
146 		b43legacydbg(ring->dev->wl,
147 		       "max_used_slots increased to %d on %s ring %d\n",
148 		       ring->max_used_slots,
149 		       ring->tx ? "TX" : "RX",
150 		       ring->index);
151 }
152 #else
153 static inline
154 void update_max_used_slots(struct b43legacy_dmaring *ring,
155 			   int current_used_slots)
156 { }
157 #endif /* DEBUG */
158 
159 /* Request a slot for usage. */
160 static inline
161 int request_slot(struct b43legacy_dmaring *ring)
162 {
163 	int slot;
164 
165 	B43legacy_WARN_ON(!ring->tx);
166 	B43legacy_WARN_ON(ring->stopped);
167 	B43legacy_WARN_ON(free_slots(ring) == 0);
168 
169 	slot = next_slot(ring, ring->current_slot);
170 	ring->current_slot = slot;
171 	ring->used_slots++;
172 
173 	update_max_used_slots(ring, ring->used_slots);
174 
175 	return slot;
176 }
177 
178 /* Mac80211-queue to b43legacy-ring mapping */
179 static struct b43legacy_dmaring *priority_to_txring(
180 						struct b43legacy_wldev *dev,
181 						int queue_priority)
182 {
183 	struct b43legacy_dmaring *ring;
184 
185 /*FIXME: For now we always run on TX-ring-1 */
186 return dev->dma.tx_ring1;
187 
188 	/* 0 = highest priority */
189 	switch (queue_priority) {
190 	default:
191 		B43legacy_WARN_ON(1);
192 		fallthrough;
193 	case 0:
194 		ring = dev->dma.tx_ring3;
195 		break;
196 	case 1:
197 		ring = dev->dma.tx_ring2;
198 		break;
199 	case 2:
200 		ring = dev->dma.tx_ring1;
201 		break;
202 	case 3:
203 		ring = dev->dma.tx_ring0;
204 		break;
205 	case 4:
206 		ring = dev->dma.tx_ring4;
207 		break;
208 	case 5:
209 		ring = dev->dma.tx_ring5;
210 		break;
211 	}
212 
213 	return ring;
214 }
215 
216 /* Bcm4301-ring to mac80211-queue mapping */
217 static inline int txring_to_priority(struct b43legacy_dmaring *ring)
218 {
219 	static const u8 idx_to_prio[] =
220 		{ 3, 2, 1, 0, 4, 5, };
221 
222 /*FIXME: have only one queue, for now */
223 return 0;
224 
225 	return idx_to_prio[ring->index];
226 }
227 
228 
229 static u16 b43legacy_dmacontroller_base(enum b43legacy_dmatype type,
230 					int controller_idx)
231 {
232 	static const u16 map32[] = {
233 		B43legacy_MMIO_DMA32_BASE0,
234 		B43legacy_MMIO_DMA32_BASE1,
235 		B43legacy_MMIO_DMA32_BASE2,
236 		B43legacy_MMIO_DMA32_BASE3,
237 		B43legacy_MMIO_DMA32_BASE4,
238 		B43legacy_MMIO_DMA32_BASE5,
239 	};
240 
241 	B43legacy_WARN_ON(!(controller_idx >= 0 &&
242 			  controller_idx < ARRAY_SIZE(map32)));
243 	return map32[controller_idx];
244 }
245 
246 static inline
247 dma_addr_t map_descbuffer(struct b43legacy_dmaring *ring,
248 			  unsigned char *buf,
249 			  size_t len,
250 			  int tx)
251 {
252 	dma_addr_t dmaaddr;
253 
254 	if (tx)
255 		dmaaddr = dma_map_single(ring->dev->dev->dma_dev,
256 					     buf, len,
257 					     DMA_TO_DEVICE);
258 	else
259 		dmaaddr = dma_map_single(ring->dev->dev->dma_dev,
260 					     buf, len,
261 					     DMA_FROM_DEVICE);
262 
263 	return dmaaddr;
264 }
265 
266 static inline
267 void unmap_descbuffer(struct b43legacy_dmaring *ring,
268 		      dma_addr_t addr,
269 		      size_t len,
270 		      int tx)
271 {
272 	if (tx)
273 		dma_unmap_single(ring->dev->dev->dma_dev,
274 				     addr, len,
275 				     DMA_TO_DEVICE);
276 	else
277 		dma_unmap_single(ring->dev->dev->dma_dev,
278 				     addr, len,
279 				     DMA_FROM_DEVICE);
280 }
281 
282 static inline
283 void sync_descbuffer_for_cpu(struct b43legacy_dmaring *ring,
284 			     dma_addr_t addr,
285 			     size_t len)
286 {
287 	B43legacy_WARN_ON(ring->tx);
288 
289 	dma_sync_single_for_cpu(ring->dev->dev->dma_dev,
290 				addr, len, DMA_FROM_DEVICE);
291 }
292 
293 static inline
294 void sync_descbuffer_for_device(struct b43legacy_dmaring *ring,
295 				dma_addr_t addr,
296 				size_t len)
297 {
298 	B43legacy_WARN_ON(ring->tx);
299 
300 	dma_sync_single_for_device(ring->dev->dev->dma_dev,
301 				   addr, len, DMA_FROM_DEVICE);
302 }
303 
304 static inline
305 void free_descriptor_buffer(struct b43legacy_dmaring *ring,
306 			    struct b43legacy_dmadesc_meta *meta,
307 			    int irq_context)
308 {
309 	if (meta->skb) {
310 		if (irq_context)
311 			dev_kfree_skb_irq(meta->skb);
312 		else
313 			dev_kfree_skb(meta->skb);
314 		meta->skb = NULL;
315 	}
316 }
317 
318 static int alloc_ringmemory(struct b43legacy_dmaring *ring)
319 {
320 	/* GFP flags must match the flags in free_ringmemory()! */
321 	ring->descbase = dma_alloc_coherent(ring->dev->dev->dma_dev,
322 					    B43legacy_DMA_RINGMEMSIZE,
323 					    &(ring->dmabase), GFP_KERNEL);
324 	if (!ring->descbase)
325 		return -ENOMEM;
326 
327 	return 0;
328 }
329 
330 static void free_ringmemory(struct b43legacy_dmaring *ring)
331 {
332 	dma_free_coherent(ring->dev->dev->dma_dev, B43legacy_DMA_RINGMEMSIZE,
333 			  ring->descbase, ring->dmabase);
334 }
335 
336 /* Reset the RX DMA channel */
337 static int b43legacy_dmacontroller_rx_reset(struct b43legacy_wldev *dev,
338 					    u16 mmio_base,
339 					    enum b43legacy_dmatype type)
340 {
341 	int i;
342 	u32 value;
343 	u16 offset;
344 
345 	might_sleep();
346 
347 	offset = B43legacy_DMA32_RXCTL;
348 	b43legacy_write32(dev, mmio_base + offset, 0);
349 	for (i = 0; i < 10; i++) {
350 		offset = B43legacy_DMA32_RXSTATUS;
351 		value = b43legacy_read32(dev, mmio_base + offset);
352 		value &= B43legacy_DMA32_RXSTATE;
353 		if (value == B43legacy_DMA32_RXSTAT_DISABLED) {
354 			i = -1;
355 			break;
356 		}
357 		msleep(1);
358 	}
359 	if (i != -1) {
360 		b43legacyerr(dev->wl, "DMA RX reset timed out\n");
361 		return -ENODEV;
362 	}
363 
364 	return 0;
365 }
366 
367 /* Reset the RX DMA channel */
368 static int b43legacy_dmacontroller_tx_reset(struct b43legacy_wldev *dev,
369 					    u16 mmio_base,
370 					    enum b43legacy_dmatype type)
371 {
372 	int i;
373 	u32 value;
374 	u16 offset;
375 
376 	might_sleep();
377 
378 	for (i = 0; i < 10; i++) {
379 		offset = B43legacy_DMA32_TXSTATUS;
380 		value = b43legacy_read32(dev, mmio_base + offset);
381 		value &= B43legacy_DMA32_TXSTATE;
382 		if (value == B43legacy_DMA32_TXSTAT_DISABLED ||
383 		    value == B43legacy_DMA32_TXSTAT_IDLEWAIT ||
384 		    value == B43legacy_DMA32_TXSTAT_STOPPED)
385 			break;
386 		msleep(1);
387 	}
388 	offset = B43legacy_DMA32_TXCTL;
389 	b43legacy_write32(dev, mmio_base + offset, 0);
390 	for (i = 0; i < 10; i++) {
391 		offset = B43legacy_DMA32_TXSTATUS;
392 		value = b43legacy_read32(dev, mmio_base + offset);
393 		value &= B43legacy_DMA32_TXSTATE;
394 		if (value == B43legacy_DMA32_TXSTAT_DISABLED) {
395 			i = -1;
396 			break;
397 		}
398 		msleep(1);
399 	}
400 	if (i != -1) {
401 		b43legacyerr(dev->wl, "DMA TX reset timed out\n");
402 		return -ENODEV;
403 	}
404 	/* ensure the reset is completed. */
405 	msleep(1);
406 
407 	return 0;
408 }
409 
410 /* Check if a DMA mapping address is invalid. */
411 static bool b43legacy_dma_mapping_error(struct b43legacy_dmaring *ring,
412 					 dma_addr_t addr,
413 					 size_t buffersize,
414 					 bool dma_to_device)
415 {
416 	if (unlikely(dma_mapping_error(ring->dev->dev->dma_dev, addr)))
417 		return true;
418 
419 	switch (ring->type) {
420 	case B43legacy_DMA_30BIT:
421 		if ((u64)addr + buffersize > (1ULL << 30))
422 			goto address_error;
423 		break;
424 	case B43legacy_DMA_32BIT:
425 		if ((u64)addr + buffersize > (1ULL << 32))
426 			goto address_error;
427 		break;
428 	}
429 
430 	/* The address is OK. */
431 	return false;
432 
433 address_error:
434 	/* We can't support this address. Unmap it again. */
435 	unmap_descbuffer(ring, addr, buffersize, dma_to_device);
436 
437 	return true;
438 }
439 
440 static int setup_rx_descbuffer(struct b43legacy_dmaring *ring,
441 			       struct b43legacy_dmadesc32 *desc,
442 			       struct b43legacy_dmadesc_meta *meta,
443 			       gfp_t gfp_flags)
444 {
445 	struct b43legacy_rxhdr_fw3 *rxhdr;
446 	struct b43legacy_hwtxstatus *txstat;
447 	dma_addr_t dmaaddr;
448 	struct sk_buff *skb;
449 
450 	B43legacy_WARN_ON(ring->tx);
451 
452 	skb = __dev_alloc_skb(ring->rx_buffersize, gfp_flags);
453 	if (unlikely(!skb))
454 		return -ENOMEM;
455 	dmaaddr = map_descbuffer(ring, skb->data,
456 				 ring->rx_buffersize, 0);
457 	if (b43legacy_dma_mapping_error(ring, dmaaddr, ring->rx_buffersize, 0)) {
458 		/* ugh. try to realloc in zone_dma */
459 		gfp_flags |= GFP_DMA;
460 
461 		dev_kfree_skb_any(skb);
462 
463 		skb = __dev_alloc_skb(ring->rx_buffersize, gfp_flags);
464 		if (unlikely(!skb))
465 			return -ENOMEM;
466 		dmaaddr = map_descbuffer(ring, skb->data,
467 					 ring->rx_buffersize, 0);
468 	}
469 
470 	if (b43legacy_dma_mapping_error(ring, dmaaddr, ring->rx_buffersize, 0)) {
471 		dev_kfree_skb_any(skb);
472 		return -EIO;
473 	}
474 
475 	meta->skb = skb;
476 	meta->dmaaddr = dmaaddr;
477 	op32_fill_descriptor(ring, desc, dmaaddr, ring->rx_buffersize, 0, 0, 0);
478 
479 	rxhdr = (struct b43legacy_rxhdr_fw3 *)(skb->data);
480 	rxhdr->frame_len = 0;
481 	txstat = (struct b43legacy_hwtxstatus *)(skb->data);
482 	txstat->cookie = 0;
483 
484 	return 0;
485 }
486 
487 /* Allocate the initial descbuffers.
488  * This is used for an RX ring only.
489  */
490 static int alloc_initial_descbuffers(struct b43legacy_dmaring *ring)
491 {
492 	int i;
493 	int err = -ENOMEM;
494 	struct b43legacy_dmadesc32 *desc;
495 	struct b43legacy_dmadesc_meta *meta;
496 
497 	for (i = 0; i < ring->nr_slots; i++) {
498 		desc = op32_idx2desc(ring, i, &meta);
499 
500 		err = setup_rx_descbuffer(ring, desc, meta, GFP_KERNEL);
501 		if (err) {
502 			b43legacyerr(ring->dev->wl,
503 			       "Failed to allocate initial descbuffers\n");
504 			goto err_unwind;
505 		}
506 	}
507 	mb(); /* all descbuffer setup before next line */
508 	ring->used_slots = ring->nr_slots;
509 	err = 0;
510 out:
511 	return err;
512 
513 err_unwind:
514 	for (i--; i >= 0; i--) {
515 		desc = op32_idx2desc(ring, i, &meta);
516 
517 		unmap_descbuffer(ring, meta->dmaaddr, ring->rx_buffersize, 0);
518 		dev_kfree_skb(meta->skb);
519 	}
520 	goto out;
521 }
522 
523 /* Do initial setup of the DMA controller.
524  * Reset the controller, write the ring busaddress
525  * and switch the "enable" bit on.
526  */
527 static int dmacontroller_setup(struct b43legacy_dmaring *ring)
528 {
529 	int err = 0;
530 	u32 value;
531 	u32 addrext;
532 	u32 trans = ring->dev->dma.translation;
533 	u32 ringbase = (u32)(ring->dmabase);
534 
535 	if (ring->tx) {
536 		addrext = (ringbase & SSB_DMA_TRANSLATION_MASK)
537 			  >> SSB_DMA_TRANSLATION_SHIFT;
538 		value = B43legacy_DMA32_TXENABLE;
539 		value |= (addrext << B43legacy_DMA32_TXADDREXT_SHIFT)
540 			& B43legacy_DMA32_TXADDREXT_MASK;
541 		b43legacy_dma_write(ring, B43legacy_DMA32_TXCTL, value);
542 		b43legacy_dma_write(ring, B43legacy_DMA32_TXRING,
543 				    (ringbase & ~SSB_DMA_TRANSLATION_MASK)
544 				    | trans);
545 	} else {
546 		err = alloc_initial_descbuffers(ring);
547 		if (err)
548 			goto out;
549 
550 		addrext = (ringbase & SSB_DMA_TRANSLATION_MASK)
551 			  >> SSB_DMA_TRANSLATION_SHIFT;
552 		value = (ring->frameoffset <<
553 			 B43legacy_DMA32_RXFROFF_SHIFT);
554 		value |= B43legacy_DMA32_RXENABLE;
555 		value |= (addrext << B43legacy_DMA32_RXADDREXT_SHIFT)
556 			 & B43legacy_DMA32_RXADDREXT_MASK;
557 		b43legacy_dma_write(ring, B43legacy_DMA32_RXCTL, value);
558 		b43legacy_dma_write(ring, B43legacy_DMA32_RXRING,
559 				    (ringbase & ~SSB_DMA_TRANSLATION_MASK)
560 				    | trans);
561 		b43legacy_dma_write(ring, B43legacy_DMA32_RXINDEX, 200);
562 	}
563 
564 out:
565 	return err;
566 }
567 
568 /* Shutdown the DMA controller. */
569 static void dmacontroller_cleanup(struct b43legacy_dmaring *ring)
570 {
571 	if (ring->tx) {
572 		b43legacy_dmacontroller_tx_reset(ring->dev, ring->mmio_base,
573 						 ring->type);
574 		b43legacy_dma_write(ring, B43legacy_DMA32_TXRING, 0);
575 	} else {
576 		b43legacy_dmacontroller_rx_reset(ring->dev, ring->mmio_base,
577 						 ring->type);
578 		b43legacy_dma_write(ring, B43legacy_DMA32_RXRING, 0);
579 	}
580 }
581 
582 static void free_all_descbuffers(struct b43legacy_dmaring *ring)
583 {
584 	struct b43legacy_dmadesc_meta *meta;
585 	int i;
586 
587 	if (!ring->used_slots)
588 		return;
589 	for (i = 0; i < ring->nr_slots; i++) {
590 		op32_idx2desc(ring, i, &meta);
591 
592 		if (!meta->skb) {
593 			B43legacy_WARN_ON(!ring->tx);
594 			continue;
595 		}
596 		if (ring->tx)
597 			unmap_descbuffer(ring, meta->dmaaddr,
598 					 meta->skb->len, 1);
599 		else
600 			unmap_descbuffer(ring, meta->dmaaddr,
601 					 ring->rx_buffersize, 0);
602 		free_descriptor_buffer(ring, meta, 0);
603 	}
604 }
605 
606 static enum b43legacy_dmatype b43legacy_engine_type(struct b43legacy_wldev *dev)
607 {
608 	u32 tmp;
609 	u16 mmio_base;
610 
611 	mmio_base = b43legacy_dmacontroller_base(0, 0);
612 	b43legacy_write32(dev,
613 			mmio_base + B43legacy_DMA32_TXCTL,
614 			B43legacy_DMA32_TXADDREXT_MASK);
615 	tmp = b43legacy_read32(dev, mmio_base +
616 			       B43legacy_DMA32_TXCTL);
617 	if (tmp & B43legacy_DMA32_TXADDREXT_MASK)
618 		return B43legacy_DMA_32BIT;
619 	return B43legacy_DMA_30BIT;
620 }
621 
622 /* Main initialization function. */
623 static
624 struct b43legacy_dmaring *b43legacy_setup_dmaring(struct b43legacy_wldev *dev,
625 						  int controller_index,
626 						  int for_tx,
627 						  enum b43legacy_dmatype type)
628 {
629 	struct b43legacy_dmaring *ring;
630 	int err;
631 	int nr_slots;
632 	dma_addr_t dma_test;
633 
634 	ring = kzalloc(sizeof(*ring), GFP_KERNEL);
635 	if (!ring)
636 		goto out;
637 	ring->type = type;
638 	ring->dev = dev;
639 
640 	nr_slots = B43legacy_RXRING_SLOTS;
641 	if (for_tx)
642 		nr_slots = B43legacy_TXRING_SLOTS;
643 
644 	ring->meta = kcalloc(nr_slots, sizeof(struct b43legacy_dmadesc_meta),
645 			     GFP_KERNEL);
646 	if (!ring->meta)
647 		goto err_kfree_ring;
648 	if (for_tx) {
649 		ring->txhdr_cache = kcalloc(nr_slots,
650 					sizeof(struct b43legacy_txhdr_fw3),
651 					GFP_KERNEL);
652 		if (!ring->txhdr_cache)
653 			goto err_kfree_meta;
654 
655 		/* test for ability to dma to txhdr_cache */
656 		dma_test = dma_map_single(dev->dev->dma_dev, ring->txhdr_cache,
657 					      sizeof(struct b43legacy_txhdr_fw3),
658 					      DMA_TO_DEVICE);
659 
660 		if (b43legacy_dma_mapping_error(ring, dma_test,
661 					sizeof(struct b43legacy_txhdr_fw3), 1)) {
662 			/* ugh realloc */
663 			kfree(ring->txhdr_cache);
664 			ring->txhdr_cache = kcalloc(nr_slots,
665 					sizeof(struct b43legacy_txhdr_fw3),
666 					GFP_KERNEL | GFP_DMA);
667 			if (!ring->txhdr_cache)
668 				goto err_kfree_meta;
669 
670 			dma_test = dma_map_single(dev->dev->dma_dev,
671 					ring->txhdr_cache,
672 					sizeof(struct b43legacy_txhdr_fw3),
673 					DMA_TO_DEVICE);
674 
675 			if (b43legacy_dma_mapping_error(ring, dma_test,
676 					sizeof(struct b43legacy_txhdr_fw3), 1))
677 				goto err_kfree_txhdr_cache;
678 		}
679 
680 		dma_unmap_single(dev->dev->dma_dev, dma_test,
681 				 sizeof(struct b43legacy_txhdr_fw3),
682 				 DMA_TO_DEVICE);
683 	}
684 
685 	ring->nr_slots = nr_slots;
686 	ring->mmio_base = b43legacy_dmacontroller_base(type, controller_index);
687 	ring->index = controller_index;
688 	if (for_tx) {
689 		ring->tx = true;
690 		ring->current_slot = -1;
691 	} else {
692 		if (ring->index == 0) {
693 			ring->rx_buffersize = B43legacy_DMA0_RX_BUFFERSIZE;
694 			ring->frameoffset = B43legacy_DMA0_RX_FRAMEOFFSET;
695 		} else if (ring->index == 3) {
696 			ring->rx_buffersize = B43legacy_DMA3_RX_BUFFERSIZE;
697 			ring->frameoffset = B43legacy_DMA3_RX_FRAMEOFFSET;
698 		} else
699 			B43legacy_WARN_ON(1);
700 	}
701 #ifdef CONFIG_B43LEGACY_DEBUG
702 	ring->last_injected_overflow = jiffies;
703 #endif
704 
705 	err = alloc_ringmemory(ring);
706 	if (err)
707 		goto err_kfree_txhdr_cache;
708 	err = dmacontroller_setup(ring);
709 	if (err)
710 		goto err_free_ringmemory;
711 
712 out:
713 	return ring;
714 
715 err_free_ringmemory:
716 	free_ringmemory(ring);
717 err_kfree_txhdr_cache:
718 	kfree(ring->txhdr_cache);
719 err_kfree_meta:
720 	kfree(ring->meta);
721 err_kfree_ring:
722 	kfree(ring);
723 	ring = NULL;
724 	goto out;
725 }
726 
727 /* Main cleanup function. */
728 static void b43legacy_destroy_dmaring(struct b43legacy_dmaring *ring)
729 {
730 	if (!ring)
731 		return;
732 
733 	b43legacydbg(ring->dev->wl, "DMA-%u 0x%04X (%s) max used slots:"
734 		     " %d/%d\n", (unsigned int)(ring->type), ring->mmio_base,
735 		     (ring->tx) ? "TX" : "RX", ring->max_used_slots,
736 		     ring->nr_slots);
737 	/* Device IRQs are disabled prior entering this function,
738 	 * so no need to take care of concurrency with rx handler stuff.
739 	 */
740 	dmacontroller_cleanup(ring);
741 	free_all_descbuffers(ring);
742 	free_ringmemory(ring);
743 
744 	kfree(ring->txhdr_cache);
745 	kfree(ring->meta);
746 	kfree(ring);
747 }
748 
749 void b43legacy_dma_free(struct b43legacy_wldev *dev)
750 {
751 	struct b43legacy_dma *dma;
752 
753 	if (b43legacy_using_pio(dev))
754 		return;
755 	dma = &dev->dma;
756 
757 	b43legacy_destroy_dmaring(dma->rx_ring3);
758 	dma->rx_ring3 = NULL;
759 	b43legacy_destroy_dmaring(dma->rx_ring0);
760 	dma->rx_ring0 = NULL;
761 
762 	b43legacy_destroy_dmaring(dma->tx_ring5);
763 	dma->tx_ring5 = NULL;
764 	b43legacy_destroy_dmaring(dma->tx_ring4);
765 	dma->tx_ring4 = NULL;
766 	b43legacy_destroy_dmaring(dma->tx_ring3);
767 	dma->tx_ring3 = NULL;
768 	b43legacy_destroy_dmaring(dma->tx_ring2);
769 	dma->tx_ring2 = NULL;
770 	b43legacy_destroy_dmaring(dma->tx_ring1);
771 	dma->tx_ring1 = NULL;
772 	b43legacy_destroy_dmaring(dma->tx_ring0);
773 	dma->tx_ring0 = NULL;
774 }
775 
776 int b43legacy_dma_init(struct b43legacy_wldev *dev)
777 {
778 	struct b43legacy_dma *dma = &dev->dma;
779 	struct b43legacy_dmaring *ring;
780 	enum b43legacy_dmatype type = b43legacy_engine_type(dev);
781 	int err;
782 
783 	err = dma_set_mask_and_coherent(dev->dev->dma_dev, DMA_BIT_MASK(type));
784 	if (err) {
785 #ifdef CONFIG_B43LEGACY_PIO
786 		b43legacywarn(dev->wl, "DMA for this device not supported. "
787 			"Falling back to PIO\n");
788 		dev->__using_pio = true;
789 		return -EAGAIN;
790 #else
791 		b43legacyerr(dev->wl, "DMA for this device not supported and "
792 		       "no PIO support compiled in\n");
793 		return -EOPNOTSUPP;
794 #endif
795 	}
796 	dma->translation = ssb_dma_translation(dev->dev);
797 
798 	err = -ENOMEM;
799 	/* setup TX DMA channels. */
800 	ring = b43legacy_setup_dmaring(dev, 0, 1, type);
801 	if (!ring)
802 		goto out;
803 	dma->tx_ring0 = ring;
804 
805 	ring = b43legacy_setup_dmaring(dev, 1, 1, type);
806 	if (!ring)
807 		goto err_destroy_tx0;
808 	dma->tx_ring1 = ring;
809 
810 	ring = b43legacy_setup_dmaring(dev, 2, 1, type);
811 	if (!ring)
812 		goto err_destroy_tx1;
813 	dma->tx_ring2 = ring;
814 
815 	ring = b43legacy_setup_dmaring(dev, 3, 1, type);
816 	if (!ring)
817 		goto err_destroy_tx2;
818 	dma->tx_ring3 = ring;
819 
820 	ring = b43legacy_setup_dmaring(dev, 4, 1, type);
821 	if (!ring)
822 		goto err_destroy_tx3;
823 	dma->tx_ring4 = ring;
824 
825 	ring = b43legacy_setup_dmaring(dev, 5, 1, type);
826 	if (!ring)
827 		goto err_destroy_tx4;
828 	dma->tx_ring5 = ring;
829 
830 	/* setup RX DMA channels. */
831 	ring = b43legacy_setup_dmaring(dev, 0, 0, type);
832 	if (!ring)
833 		goto err_destroy_tx5;
834 	dma->rx_ring0 = ring;
835 
836 	if (dev->dev->id.revision < 5) {
837 		ring = b43legacy_setup_dmaring(dev, 3, 0, type);
838 		if (!ring)
839 			goto err_destroy_rx0;
840 		dma->rx_ring3 = ring;
841 	}
842 
843 	b43legacydbg(dev->wl, "%u-bit DMA initialized\n", (unsigned int)type);
844 	err = 0;
845 out:
846 	return err;
847 
848 err_destroy_rx0:
849 	b43legacy_destroy_dmaring(dma->rx_ring0);
850 	dma->rx_ring0 = NULL;
851 err_destroy_tx5:
852 	b43legacy_destroy_dmaring(dma->tx_ring5);
853 	dma->tx_ring5 = NULL;
854 err_destroy_tx4:
855 	b43legacy_destroy_dmaring(dma->tx_ring4);
856 	dma->tx_ring4 = NULL;
857 err_destroy_tx3:
858 	b43legacy_destroy_dmaring(dma->tx_ring3);
859 	dma->tx_ring3 = NULL;
860 err_destroy_tx2:
861 	b43legacy_destroy_dmaring(dma->tx_ring2);
862 	dma->tx_ring2 = NULL;
863 err_destroy_tx1:
864 	b43legacy_destroy_dmaring(dma->tx_ring1);
865 	dma->tx_ring1 = NULL;
866 err_destroy_tx0:
867 	b43legacy_destroy_dmaring(dma->tx_ring0);
868 	dma->tx_ring0 = NULL;
869 	goto out;
870 }
871 
872 /* Generate a cookie for the TX header. */
873 static u16 generate_cookie(struct b43legacy_dmaring *ring,
874 			   int slot)
875 {
876 	u16 cookie = 0x1000;
877 
878 	/* Use the upper 4 bits of the cookie as
879 	 * DMA controller ID and store the slot number
880 	 * in the lower 12 bits.
881 	 * Note that the cookie must never be 0, as this
882 	 * is a special value used in RX path.
883 	 */
884 	switch (ring->index) {
885 	case 0:
886 		cookie = 0xA000;
887 		break;
888 	case 1:
889 		cookie = 0xB000;
890 		break;
891 	case 2:
892 		cookie = 0xC000;
893 		break;
894 	case 3:
895 		cookie = 0xD000;
896 		break;
897 	case 4:
898 		cookie = 0xE000;
899 		break;
900 	case 5:
901 		cookie = 0xF000;
902 		break;
903 	}
904 	B43legacy_WARN_ON(!(((u16)slot & 0xF000) == 0x0000));
905 	cookie |= (u16)slot;
906 
907 	return cookie;
908 }
909 
910 /* Inspect a cookie and find out to which controller/slot it belongs. */
911 static
912 struct b43legacy_dmaring *parse_cookie(struct b43legacy_wldev *dev,
913 				      u16 cookie, int *slot)
914 {
915 	struct b43legacy_dma *dma = &dev->dma;
916 	struct b43legacy_dmaring *ring = NULL;
917 
918 	switch (cookie & 0xF000) {
919 	case 0xA000:
920 		ring = dma->tx_ring0;
921 		break;
922 	case 0xB000:
923 		ring = dma->tx_ring1;
924 		break;
925 	case 0xC000:
926 		ring = dma->tx_ring2;
927 		break;
928 	case 0xD000:
929 		ring = dma->tx_ring3;
930 		break;
931 	case 0xE000:
932 		ring = dma->tx_ring4;
933 		break;
934 	case 0xF000:
935 		ring = dma->tx_ring5;
936 		break;
937 	default:
938 		B43legacy_WARN_ON(1);
939 	}
940 	*slot = (cookie & 0x0FFF);
941 	B43legacy_WARN_ON(!(ring && *slot >= 0 && *slot < ring->nr_slots));
942 
943 	return ring;
944 }
945 
946 static int dma_tx_fragment(struct b43legacy_dmaring *ring,
947 			    struct sk_buff **in_skb)
948 {
949 	struct sk_buff *skb = *in_skb;
950 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
951 	u8 *header;
952 	int slot, old_top_slot, old_used_slots;
953 	int err;
954 	struct b43legacy_dmadesc32 *desc;
955 	struct b43legacy_dmadesc_meta *meta;
956 	struct b43legacy_dmadesc_meta *meta_hdr;
957 	struct sk_buff *bounce_skb;
958 
959 #define SLOTS_PER_PACKET  2
960 	B43legacy_WARN_ON(skb_shinfo(skb)->nr_frags != 0);
961 
962 	old_top_slot = ring->current_slot;
963 	old_used_slots = ring->used_slots;
964 
965 	/* Get a slot for the header. */
966 	slot = request_slot(ring);
967 	desc = op32_idx2desc(ring, slot, &meta_hdr);
968 	memset(meta_hdr, 0, sizeof(*meta_hdr));
969 
970 	header = &(ring->txhdr_cache[slot * sizeof(
971 			       struct b43legacy_txhdr_fw3)]);
972 	err = b43legacy_generate_txhdr(ring->dev, header,
973 				 skb->data, skb->len, info,
974 				 generate_cookie(ring, slot));
975 	if (unlikely(err)) {
976 		ring->current_slot = old_top_slot;
977 		ring->used_slots = old_used_slots;
978 		return err;
979 	}
980 
981 	meta_hdr->dmaaddr = map_descbuffer(ring, (unsigned char *)header,
982 					   sizeof(struct b43legacy_txhdr_fw3), 1);
983 	if (b43legacy_dma_mapping_error(ring, meta_hdr->dmaaddr,
984 					sizeof(struct b43legacy_txhdr_fw3), 1)) {
985 		ring->current_slot = old_top_slot;
986 		ring->used_slots = old_used_slots;
987 		return -EIO;
988 	}
989 	op32_fill_descriptor(ring, desc, meta_hdr->dmaaddr,
990 			     sizeof(struct b43legacy_txhdr_fw3), 1, 0, 0);
991 
992 	/* Get a slot for the payload. */
993 	slot = request_slot(ring);
994 	desc = op32_idx2desc(ring, slot, &meta);
995 	memset(meta, 0, sizeof(*meta));
996 
997 	meta->skb = skb;
998 	meta->is_last_fragment = true;
999 
1000 	meta->dmaaddr = map_descbuffer(ring, skb->data, skb->len, 1);
1001 	/* create a bounce buffer in zone_dma on mapping failure. */
1002 	if (b43legacy_dma_mapping_error(ring, meta->dmaaddr, skb->len, 1)) {
1003 		bounce_skb = alloc_skb(skb->len, GFP_KERNEL | GFP_DMA);
1004 		if (!bounce_skb) {
1005 			ring->current_slot = old_top_slot;
1006 			ring->used_slots = old_used_slots;
1007 			err = -ENOMEM;
1008 			goto out_unmap_hdr;
1009 		}
1010 
1011 		skb_put_data(bounce_skb, skb->data, skb->len);
1012 		memcpy(bounce_skb->cb, skb->cb, sizeof(skb->cb));
1013 		bounce_skb->dev = skb->dev;
1014 		skb_set_queue_mapping(bounce_skb, skb_get_queue_mapping(skb));
1015 		info = IEEE80211_SKB_CB(bounce_skb);
1016 
1017 		dev_kfree_skb_any(skb);
1018 		skb = bounce_skb;
1019 		*in_skb = bounce_skb;
1020 		meta->skb = skb;
1021 		meta->dmaaddr = map_descbuffer(ring, skb->data, skb->len, 1);
1022 		if (b43legacy_dma_mapping_error(ring, meta->dmaaddr, skb->len, 1)) {
1023 			ring->current_slot = old_top_slot;
1024 			ring->used_slots = old_used_slots;
1025 			err = -EIO;
1026 			goto out_free_bounce;
1027 		}
1028 	}
1029 
1030 	op32_fill_descriptor(ring, desc, meta->dmaaddr,
1031 			     skb->len, 0, 1, 1);
1032 
1033 	wmb();	/* previous stuff MUST be done */
1034 	/* Now transfer the whole frame. */
1035 	op32_poke_tx(ring, next_slot(ring, slot));
1036 	return 0;
1037 
1038 out_free_bounce:
1039 	dev_kfree_skb_any(skb);
1040 out_unmap_hdr:
1041 	unmap_descbuffer(ring, meta_hdr->dmaaddr,
1042 			 sizeof(struct b43legacy_txhdr_fw3), 1);
1043 	return err;
1044 }
1045 
1046 static inline
1047 int should_inject_overflow(struct b43legacy_dmaring *ring)
1048 {
1049 #ifdef CONFIG_B43LEGACY_DEBUG
1050 	if (unlikely(b43legacy_debug(ring->dev,
1051 				     B43legacy_DBG_DMAOVERFLOW))) {
1052 		/* Check if we should inject another ringbuffer overflow
1053 		 * to test handling of this situation in the stack. */
1054 		unsigned long next_overflow;
1055 
1056 		next_overflow = ring->last_injected_overflow + HZ;
1057 		if (time_after(jiffies, next_overflow)) {
1058 			ring->last_injected_overflow = jiffies;
1059 			b43legacydbg(ring->dev->wl,
1060 			       "Injecting TX ring overflow on "
1061 			       "DMA controller %d\n", ring->index);
1062 			return 1;
1063 		}
1064 	}
1065 #endif /* CONFIG_B43LEGACY_DEBUG */
1066 	return 0;
1067 }
1068 
1069 int b43legacy_dma_tx(struct b43legacy_wldev *dev,
1070 		     struct sk_buff *skb)
1071 {
1072 	struct b43legacy_dmaring *ring;
1073 	int err = 0;
1074 
1075 	ring = priority_to_txring(dev, skb_get_queue_mapping(skb));
1076 	B43legacy_WARN_ON(!ring->tx);
1077 
1078 	if (unlikely(ring->stopped)) {
1079 		/* We get here only because of a bug in mac80211.
1080 		 * Because of a race, one packet may be queued after
1081 		 * the queue is stopped, thus we got called when we shouldn't.
1082 		 * For now, just refuse the transmit. */
1083 		if (b43legacy_debug(dev, B43legacy_DBG_DMAVERBOSE))
1084 			b43legacyerr(dev->wl, "Packet after queue stopped\n");
1085 		return -ENOSPC;
1086 	}
1087 
1088 	if (WARN_ON(free_slots(ring) < SLOTS_PER_PACKET)) {
1089 		/* If we get here, we have a real error with the queue
1090 		 * full, but queues not stopped. */
1091 		b43legacyerr(dev->wl, "DMA queue overflow\n");
1092 		return -ENOSPC;
1093 	}
1094 
1095 	/* dma_tx_fragment might reallocate the skb, so invalidate pointers pointing
1096 	 * into the skb data or cb now. */
1097 	err = dma_tx_fragment(ring, &skb);
1098 	if (unlikely(err == -ENOKEY)) {
1099 		/* Drop this packet, as we don't have the encryption key
1100 		 * anymore and must not transmit it unencrypted. */
1101 		dev_kfree_skb_any(skb);
1102 		return 0;
1103 	}
1104 	if (unlikely(err)) {
1105 		b43legacyerr(dev->wl, "DMA tx mapping failure\n");
1106 		return err;
1107 	}
1108 	if ((free_slots(ring) < SLOTS_PER_PACKET) ||
1109 	    should_inject_overflow(ring)) {
1110 		/* This TX ring is full. */
1111 		unsigned int skb_mapping = skb_get_queue_mapping(skb);
1112 		ieee80211_stop_queue(dev->wl->hw, skb_mapping);
1113 		dev->wl->tx_queue_stopped[skb_mapping] = 1;
1114 		ring->stopped = true;
1115 		if (b43legacy_debug(dev, B43legacy_DBG_DMAVERBOSE))
1116 			b43legacydbg(dev->wl, "Stopped TX ring %d\n",
1117 			       ring->index);
1118 	}
1119 	return err;
1120 }
1121 
1122 void b43legacy_dma_handle_txstatus(struct b43legacy_wldev *dev,
1123 				 const struct b43legacy_txstatus *status)
1124 {
1125 	struct b43legacy_dmaring *ring;
1126 	struct b43legacy_dmadesc_meta *meta;
1127 	int retry_limit;
1128 	int slot;
1129 	int firstused;
1130 
1131 	ring = parse_cookie(dev, status->cookie, &slot);
1132 	if (unlikely(!ring))
1133 		return;
1134 	B43legacy_WARN_ON(!ring->tx);
1135 
1136 	/* Sanity check: TX packets are processed in-order on one ring.
1137 	 * Check if the slot deduced from the cookie really is the first
1138 	 * used slot. */
1139 	firstused = ring->current_slot - ring->used_slots + 1;
1140 	if (firstused < 0)
1141 		firstused = ring->nr_slots + firstused;
1142 	if (unlikely(slot != firstused)) {
1143 		/* This possibly is a firmware bug and will result in
1144 		 * malfunction, memory leaks and/or stall of DMA functionality.
1145 		 */
1146 		b43legacydbg(dev->wl, "Out of order TX status report on DMA "
1147 			     "ring %d. Expected %d, but got %d\n",
1148 			     ring->index, firstused, slot);
1149 		return;
1150 	}
1151 
1152 	while (1) {
1153 		B43legacy_WARN_ON(!(slot >= 0 && slot < ring->nr_slots));
1154 		op32_idx2desc(ring, slot, &meta);
1155 
1156 		if (meta->skb)
1157 			unmap_descbuffer(ring, meta->dmaaddr,
1158 					 meta->skb->len, 1);
1159 		else
1160 			unmap_descbuffer(ring, meta->dmaaddr,
1161 					 sizeof(struct b43legacy_txhdr_fw3),
1162 					 1);
1163 
1164 		if (meta->is_last_fragment) {
1165 			struct ieee80211_tx_info *info;
1166 			BUG_ON(!meta->skb);
1167 			info = IEEE80211_SKB_CB(meta->skb);
1168 
1169 			/* preserve the confiured retry limit before clearing the status
1170 			 * The xmit function has overwritten the rc's value with the actual
1171 			 * retry limit done by the hardware */
1172 			retry_limit = info->status.rates[0].count;
1173 			ieee80211_tx_info_clear_status(info);
1174 
1175 			if (status->acked)
1176 				info->flags |= IEEE80211_TX_STAT_ACK;
1177 
1178 			if (status->rts_count > dev->wl->hw->conf.short_frame_max_tx_count) {
1179 				/*
1180 				 * If the short retries (RTS, not data frame) have exceeded
1181 				 * the limit, the hw will not have tried the selected rate,
1182 				 * but will have used the fallback rate instead.
1183 				 * Don't let the rate control count attempts for the selected
1184 				 * rate in this case, otherwise the statistics will be off.
1185 				 */
1186 				info->status.rates[0].count = 0;
1187 				info->status.rates[1].count = status->frame_count;
1188 			} else {
1189 				if (status->frame_count > retry_limit) {
1190 					info->status.rates[0].count = retry_limit;
1191 					info->status.rates[1].count = status->frame_count -
1192 							retry_limit;
1193 
1194 				} else {
1195 					info->status.rates[0].count = status->frame_count;
1196 					info->status.rates[1].idx = -1;
1197 				}
1198 			}
1199 
1200 			/* Call back to inform the ieee80211 subsystem about the
1201 			 * status of the transmission.
1202 			 * Some fields of txstat are already filled in dma_tx().
1203 			 */
1204 			ieee80211_tx_status_irqsafe(dev->wl->hw, meta->skb);
1205 			/* skb is freed by ieee80211_tx_status_irqsafe() */
1206 			meta->skb = NULL;
1207 		} else {
1208 			/* No need to call free_descriptor_buffer here, as
1209 			 * this is only the txhdr, which is not allocated.
1210 			 */
1211 			B43legacy_WARN_ON(meta->skb != NULL);
1212 		}
1213 
1214 		/* Everything unmapped and free'd. So it's not used anymore. */
1215 		ring->used_slots--;
1216 
1217 		if (meta->is_last_fragment)
1218 			break;
1219 		slot = next_slot(ring, slot);
1220 	}
1221 	dev->stats.last_tx = jiffies;
1222 	if (ring->stopped) {
1223 		B43legacy_WARN_ON(free_slots(ring) < SLOTS_PER_PACKET);
1224 		ring->stopped = false;
1225 	}
1226 
1227 	if (dev->wl->tx_queue_stopped[ring->queue_prio]) {
1228 		dev->wl->tx_queue_stopped[ring->queue_prio] = 0;
1229 	} else {
1230 		/* If the driver queue is running wake the corresponding
1231 		 * mac80211 queue. */
1232 		ieee80211_wake_queue(dev->wl->hw, ring->queue_prio);
1233 		if (b43legacy_debug(dev, B43legacy_DBG_DMAVERBOSE))
1234 			b43legacydbg(dev->wl, "Woke up TX ring %d\n",
1235 				     ring->index);
1236 	}
1237 	/* Add work to the queue. */
1238 	ieee80211_queue_work(dev->wl->hw, &dev->wl->tx_work);
1239 }
1240 
1241 static void dma_rx(struct b43legacy_dmaring *ring,
1242 		   int *slot)
1243 {
1244 	struct b43legacy_dmadesc32 *desc;
1245 	struct b43legacy_dmadesc_meta *meta;
1246 	struct b43legacy_rxhdr_fw3 *rxhdr;
1247 	struct sk_buff *skb;
1248 	u16 len;
1249 	int err;
1250 	dma_addr_t dmaaddr;
1251 
1252 	desc = op32_idx2desc(ring, *slot, &meta);
1253 
1254 	sync_descbuffer_for_cpu(ring, meta->dmaaddr, ring->rx_buffersize);
1255 	skb = meta->skb;
1256 
1257 	if (ring->index == 3) {
1258 		/* We received an xmit status. */
1259 		struct b43legacy_hwtxstatus *hw =
1260 				(struct b43legacy_hwtxstatus *)skb->data;
1261 		int i = 0;
1262 
1263 		while (hw->cookie == 0) {
1264 			if (i > 100)
1265 				break;
1266 			i++;
1267 			udelay(2);
1268 			barrier();
1269 		}
1270 		b43legacy_handle_hwtxstatus(ring->dev, hw);
1271 		/* recycle the descriptor buffer. */
1272 		sync_descbuffer_for_device(ring, meta->dmaaddr,
1273 					   ring->rx_buffersize);
1274 
1275 		return;
1276 	}
1277 	rxhdr = (struct b43legacy_rxhdr_fw3 *)skb->data;
1278 	len = le16_to_cpu(rxhdr->frame_len);
1279 	if (len == 0) {
1280 		int i = 0;
1281 
1282 		do {
1283 			udelay(2);
1284 			barrier();
1285 			len = le16_to_cpu(rxhdr->frame_len);
1286 		} while (len == 0 && i++ < 5);
1287 		if (unlikely(len == 0)) {
1288 			/* recycle the descriptor buffer. */
1289 			sync_descbuffer_for_device(ring, meta->dmaaddr,
1290 						   ring->rx_buffersize);
1291 			goto drop;
1292 		}
1293 	}
1294 	if (unlikely(len > ring->rx_buffersize)) {
1295 		/* The data did not fit into one descriptor buffer
1296 		 * and is split over multiple buffers.
1297 		 * This should never happen, as we try to allocate buffers
1298 		 * big enough. So simply ignore this packet.
1299 		 */
1300 		int cnt = 0;
1301 		s32 tmp = len;
1302 
1303 		while (1) {
1304 			desc = op32_idx2desc(ring, *slot, &meta);
1305 			/* recycle the descriptor buffer. */
1306 			sync_descbuffer_for_device(ring, meta->dmaaddr,
1307 						   ring->rx_buffersize);
1308 			*slot = next_slot(ring, *slot);
1309 			cnt++;
1310 			tmp -= ring->rx_buffersize;
1311 			if (tmp <= 0)
1312 				break;
1313 		}
1314 		b43legacyerr(ring->dev->wl, "DMA RX buffer too small "
1315 		       "(len: %u, buffer: %u, nr-dropped: %d)\n",
1316 		       len, ring->rx_buffersize, cnt);
1317 		goto drop;
1318 	}
1319 
1320 	dmaaddr = meta->dmaaddr;
1321 	err = setup_rx_descbuffer(ring, desc, meta, GFP_ATOMIC);
1322 	if (unlikely(err)) {
1323 		b43legacydbg(ring->dev->wl, "DMA RX: setup_rx_descbuffer()"
1324 			     " failed\n");
1325 		sync_descbuffer_for_device(ring, dmaaddr,
1326 					   ring->rx_buffersize);
1327 		goto drop;
1328 	}
1329 
1330 	unmap_descbuffer(ring, dmaaddr, ring->rx_buffersize, 0);
1331 	skb_put(skb, len + ring->frameoffset);
1332 	skb_pull(skb, ring->frameoffset);
1333 
1334 	b43legacy_rx(ring->dev, skb, rxhdr);
1335 drop:
1336 	return;
1337 }
1338 
1339 void b43legacy_dma_rx(struct b43legacy_dmaring *ring)
1340 {
1341 	int slot;
1342 	int current_slot;
1343 	int used_slots = 0;
1344 
1345 	B43legacy_WARN_ON(ring->tx);
1346 	current_slot = op32_get_current_rxslot(ring);
1347 	B43legacy_WARN_ON(!(current_slot >= 0 && current_slot <
1348 			   ring->nr_slots));
1349 
1350 	slot = ring->current_slot;
1351 	for (; slot != current_slot; slot = next_slot(ring, slot)) {
1352 		dma_rx(ring, &slot);
1353 		update_max_used_slots(ring, ++used_slots);
1354 	}
1355 	op32_set_current_rxslot(ring, slot);
1356 	ring->current_slot = slot;
1357 }
1358 
1359 static void b43legacy_dma_tx_suspend_ring(struct b43legacy_dmaring *ring)
1360 {
1361 	B43legacy_WARN_ON(!ring->tx);
1362 	op32_tx_suspend(ring);
1363 }
1364 
1365 static void b43legacy_dma_tx_resume_ring(struct b43legacy_dmaring *ring)
1366 {
1367 	B43legacy_WARN_ON(!ring->tx);
1368 	op32_tx_resume(ring);
1369 }
1370 
1371 void b43legacy_dma_tx_suspend(struct b43legacy_wldev *dev)
1372 {
1373 	b43legacy_power_saving_ctl_bits(dev, -1, 1);
1374 	b43legacy_dma_tx_suspend_ring(dev->dma.tx_ring0);
1375 	b43legacy_dma_tx_suspend_ring(dev->dma.tx_ring1);
1376 	b43legacy_dma_tx_suspend_ring(dev->dma.tx_ring2);
1377 	b43legacy_dma_tx_suspend_ring(dev->dma.tx_ring3);
1378 	b43legacy_dma_tx_suspend_ring(dev->dma.tx_ring4);
1379 	b43legacy_dma_tx_suspend_ring(dev->dma.tx_ring5);
1380 }
1381 
1382 void b43legacy_dma_tx_resume(struct b43legacy_wldev *dev)
1383 {
1384 	b43legacy_dma_tx_resume_ring(dev->dma.tx_ring5);
1385 	b43legacy_dma_tx_resume_ring(dev->dma.tx_ring4);
1386 	b43legacy_dma_tx_resume_ring(dev->dma.tx_ring3);
1387 	b43legacy_dma_tx_resume_ring(dev->dma.tx_ring2);
1388 	b43legacy_dma_tx_resume_ring(dev->dma.tx_ring1);
1389 	b43legacy_dma_tx_resume_ring(dev->dma.tx_ring0);
1390 	b43legacy_power_saving_ctl_bits(dev, -1, -1);
1391 }
1392