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 u64 supported_dma_mask(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 DMA_BIT_MASK(32);
619 
620 	return DMA_BIT_MASK(30);
621 }
622 
623 static enum b43legacy_dmatype dma_mask_to_engine_type(u64 dmamask)
624 {
625 	if (dmamask == DMA_BIT_MASK(30))
626 		return B43legacy_DMA_30BIT;
627 	if (dmamask == DMA_BIT_MASK(32))
628 		return B43legacy_DMA_32BIT;
629 	B43legacy_WARN_ON(1);
630 	return B43legacy_DMA_30BIT;
631 }
632 
633 /* Main initialization function. */
634 static
635 struct b43legacy_dmaring *b43legacy_setup_dmaring(struct b43legacy_wldev *dev,
636 						  int controller_index,
637 						  int for_tx,
638 						  enum b43legacy_dmatype type)
639 {
640 	struct b43legacy_dmaring *ring;
641 	int err;
642 	int nr_slots;
643 	dma_addr_t dma_test;
644 
645 	ring = kzalloc(sizeof(*ring), GFP_KERNEL);
646 	if (!ring)
647 		goto out;
648 	ring->type = type;
649 	ring->dev = dev;
650 
651 	nr_slots = B43legacy_RXRING_SLOTS;
652 	if (for_tx)
653 		nr_slots = B43legacy_TXRING_SLOTS;
654 
655 	ring->meta = kcalloc(nr_slots, sizeof(struct b43legacy_dmadesc_meta),
656 			     GFP_KERNEL);
657 	if (!ring->meta)
658 		goto err_kfree_ring;
659 	if (for_tx) {
660 		ring->txhdr_cache = kcalloc(nr_slots,
661 					sizeof(struct b43legacy_txhdr_fw3),
662 					GFP_KERNEL);
663 		if (!ring->txhdr_cache)
664 			goto err_kfree_meta;
665 
666 		/* test for ability to dma to txhdr_cache */
667 		dma_test = dma_map_single(dev->dev->dma_dev, ring->txhdr_cache,
668 					      sizeof(struct b43legacy_txhdr_fw3),
669 					      DMA_TO_DEVICE);
670 
671 		if (b43legacy_dma_mapping_error(ring, dma_test,
672 					sizeof(struct b43legacy_txhdr_fw3), 1)) {
673 			/* ugh realloc */
674 			kfree(ring->txhdr_cache);
675 			ring->txhdr_cache = kcalloc(nr_slots,
676 					sizeof(struct b43legacy_txhdr_fw3),
677 					GFP_KERNEL | GFP_DMA);
678 			if (!ring->txhdr_cache)
679 				goto err_kfree_meta;
680 
681 			dma_test = dma_map_single(dev->dev->dma_dev,
682 					ring->txhdr_cache,
683 					sizeof(struct b43legacy_txhdr_fw3),
684 					DMA_TO_DEVICE);
685 
686 			if (b43legacy_dma_mapping_error(ring, dma_test,
687 					sizeof(struct b43legacy_txhdr_fw3), 1))
688 				goto err_kfree_txhdr_cache;
689 		}
690 
691 		dma_unmap_single(dev->dev->dma_dev, dma_test,
692 				 sizeof(struct b43legacy_txhdr_fw3),
693 				 DMA_TO_DEVICE);
694 	}
695 
696 	ring->nr_slots = nr_slots;
697 	ring->mmio_base = b43legacy_dmacontroller_base(type, controller_index);
698 	ring->index = controller_index;
699 	if (for_tx) {
700 		ring->tx = true;
701 		ring->current_slot = -1;
702 	} else {
703 		if (ring->index == 0) {
704 			ring->rx_buffersize = B43legacy_DMA0_RX_BUFFERSIZE;
705 			ring->frameoffset = B43legacy_DMA0_RX_FRAMEOFFSET;
706 		} else if (ring->index == 3) {
707 			ring->rx_buffersize = B43legacy_DMA3_RX_BUFFERSIZE;
708 			ring->frameoffset = B43legacy_DMA3_RX_FRAMEOFFSET;
709 		} else
710 			B43legacy_WARN_ON(1);
711 	}
712 #ifdef CONFIG_B43LEGACY_DEBUG
713 	ring->last_injected_overflow = jiffies;
714 #endif
715 
716 	err = alloc_ringmemory(ring);
717 	if (err)
718 		goto err_kfree_txhdr_cache;
719 	err = dmacontroller_setup(ring);
720 	if (err)
721 		goto err_free_ringmemory;
722 
723 out:
724 	return ring;
725 
726 err_free_ringmemory:
727 	free_ringmemory(ring);
728 err_kfree_txhdr_cache:
729 	kfree(ring->txhdr_cache);
730 err_kfree_meta:
731 	kfree(ring->meta);
732 err_kfree_ring:
733 	kfree(ring);
734 	ring = NULL;
735 	goto out;
736 }
737 
738 /* Main cleanup function. */
739 static void b43legacy_destroy_dmaring(struct b43legacy_dmaring *ring)
740 {
741 	if (!ring)
742 		return;
743 
744 	b43legacydbg(ring->dev->wl, "DMA-%u 0x%04X (%s) max used slots:"
745 		     " %d/%d\n", (unsigned int)(ring->type), ring->mmio_base,
746 		     (ring->tx) ? "TX" : "RX", ring->max_used_slots,
747 		     ring->nr_slots);
748 	/* Device IRQs are disabled prior entering this function,
749 	 * so no need to take care of concurrency with rx handler stuff.
750 	 */
751 	dmacontroller_cleanup(ring);
752 	free_all_descbuffers(ring);
753 	free_ringmemory(ring);
754 
755 	kfree(ring->txhdr_cache);
756 	kfree(ring->meta);
757 	kfree(ring);
758 }
759 
760 void b43legacy_dma_free(struct b43legacy_wldev *dev)
761 {
762 	struct b43legacy_dma *dma;
763 
764 	if (b43legacy_using_pio(dev))
765 		return;
766 	dma = &dev->dma;
767 
768 	b43legacy_destroy_dmaring(dma->rx_ring3);
769 	dma->rx_ring3 = NULL;
770 	b43legacy_destroy_dmaring(dma->rx_ring0);
771 	dma->rx_ring0 = NULL;
772 
773 	b43legacy_destroy_dmaring(dma->tx_ring5);
774 	dma->tx_ring5 = NULL;
775 	b43legacy_destroy_dmaring(dma->tx_ring4);
776 	dma->tx_ring4 = NULL;
777 	b43legacy_destroy_dmaring(dma->tx_ring3);
778 	dma->tx_ring3 = NULL;
779 	b43legacy_destroy_dmaring(dma->tx_ring2);
780 	dma->tx_ring2 = NULL;
781 	b43legacy_destroy_dmaring(dma->tx_ring1);
782 	dma->tx_ring1 = NULL;
783 	b43legacy_destroy_dmaring(dma->tx_ring0);
784 	dma->tx_ring0 = NULL;
785 }
786 
787 static int b43legacy_dma_set_mask(struct b43legacy_wldev *dev, u64 mask)
788 {
789 	u64 orig_mask = mask;
790 	bool fallback = false;
791 	int err;
792 
793 	/* Try to set the DMA mask. If it fails, try falling back to a
794 	 * lower mask, as we can always also support a lower one. */
795 	while (1) {
796 		err = dma_set_mask_and_coherent(dev->dev->dma_dev, mask);
797 		if (!err)
798 			break;
799 		if (mask == DMA_BIT_MASK(64)) {
800 			mask = DMA_BIT_MASK(32);
801 			fallback = true;
802 			continue;
803 		}
804 		if (mask == DMA_BIT_MASK(32)) {
805 			mask = DMA_BIT_MASK(30);
806 			fallback = true;
807 			continue;
808 		}
809 		b43legacyerr(dev->wl, "The machine/kernel does not support "
810 		       "the required %u-bit DMA mask\n",
811 		       (unsigned int)dma_mask_to_engine_type(orig_mask));
812 		return -EOPNOTSUPP;
813 	}
814 	if (fallback) {
815 		b43legacyinfo(dev->wl, "DMA mask fallback from %u-bit to %u-"
816 			"bit\n",
817 			(unsigned int)dma_mask_to_engine_type(orig_mask),
818 			(unsigned int)dma_mask_to_engine_type(mask));
819 	}
820 
821 	return 0;
822 }
823 
824 int b43legacy_dma_init(struct b43legacy_wldev *dev)
825 {
826 	struct b43legacy_dma *dma = &dev->dma;
827 	struct b43legacy_dmaring *ring;
828 	int err;
829 	u64 dmamask;
830 	enum b43legacy_dmatype type;
831 
832 	dmamask = supported_dma_mask(dev);
833 	type = dma_mask_to_engine_type(dmamask);
834 	err = b43legacy_dma_set_mask(dev, dmamask);
835 	if (err) {
836 #ifdef CONFIG_B43LEGACY_PIO
837 		b43legacywarn(dev->wl, "DMA for this device not supported. "
838 			"Falling back to PIO\n");
839 		dev->__using_pio = true;
840 		return -EAGAIN;
841 #else
842 		b43legacyerr(dev->wl, "DMA for this device not supported and "
843 		       "no PIO support compiled in\n");
844 		return -EOPNOTSUPP;
845 #endif
846 	}
847 	dma->translation = ssb_dma_translation(dev->dev);
848 
849 	err = -ENOMEM;
850 	/* setup TX DMA channels. */
851 	ring = b43legacy_setup_dmaring(dev, 0, 1, type);
852 	if (!ring)
853 		goto out;
854 	dma->tx_ring0 = ring;
855 
856 	ring = b43legacy_setup_dmaring(dev, 1, 1, type);
857 	if (!ring)
858 		goto err_destroy_tx0;
859 	dma->tx_ring1 = ring;
860 
861 	ring = b43legacy_setup_dmaring(dev, 2, 1, type);
862 	if (!ring)
863 		goto err_destroy_tx1;
864 	dma->tx_ring2 = ring;
865 
866 	ring = b43legacy_setup_dmaring(dev, 3, 1, type);
867 	if (!ring)
868 		goto err_destroy_tx2;
869 	dma->tx_ring3 = ring;
870 
871 	ring = b43legacy_setup_dmaring(dev, 4, 1, type);
872 	if (!ring)
873 		goto err_destroy_tx3;
874 	dma->tx_ring4 = ring;
875 
876 	ring = b43legacy_setup_dmaring(dev, 5, 1, type);
877 	if (!ring)
878 		goto err_destroy_tx4;
879 	dma->tx_ring5 = ring;
880 
881 	/* setup RX DMA channels. */
882 	ring = b43legacy_setup_dmaring(dev, 0, 0, type);
883 	if (!ring)
884 		goto err_destroy_tx5;
885 	dma->rx_ring0 = ring;
886 
887 	if (dev->dev->id.revision < 5) {
888 		ring = b43legacy_setup_dmaring(dev, 3, 0, type);
889 		if (!ring)
890 			goto err_destroy_rx0;
891 		dma->rx_ring3 = ring;
892 	}
893 
894 	b43legacydbg(dev->wl, "%u-bit DMA initialized\n", (unsigned int)type);
895 	err = 0;
896 out:
897 	return err;
898 
899 err_destroy_rx0:
900 	b43legacy_destroy_dmaring(dma->rx_ring0);
901 	dma->rx_ring0 = NULL;
902 err_destroy_tx5:
903 	b43legacy_destroy_dmaring(dma->tx_ring5);
904 	dma->tx_ring5 = NULL;
905 err_destroy_tx4:
906 	b43legacy_destroy_dmaring(dma->tx_ring4);
907 	dma->tx_ring4 = NULL;
908 err_destroy_tx3:
909 	b43legacy_destroy_dmaring(dma->tx_ring3);
910 	dma->tx_ring3 = NULL;
911 err_destroy_tx2:
912 	b43legacy_destroy_dmaring(dma->tx_ring2);
913 	dma->tx_ring2 = NULL;
914 err_destroy_tx1:
915 	b43legacy_destroy_dmaring(dma->tx_ring1);
916 	dma->tx_ring1 = NULL;
917 err_destroy_tx0:
918 	b43legacy_destroy_dmaring(dma->tx_ring0);
919 	dma->tx_ring0 = NULL;
920 	goto out;
921 }
922 
923 /* Generate a cookie for the TX header. */
924 static u16 generate_cookie(struct b43legacy_dmaring *ring,
925 			   int slot)
926 {
927 	u16 cookie = 0x1000;
928 
929 	/* Use the upper 4 bits of the cookie as
930 	 * DMA controller ID and store the slot number
931 	 * in the lower 12 bits.
932 	 * Note that the cookie must never be 0, as this
933 	 * is a special value used in RX path.
934 	 */
935 	switch (ring->index) {
936 	case 0:
937 		cookie = 0xA000;
938 		break;
939 	case 1:
940 		cookie = 0xB000;
941 		break;
942 	case 2:
943 		cookie = 0xC000;
944 		break;
945 	case 3:
946 		cookie = 0xD000;
947 		break;
948 	case 4:
949 		cookie = 0xE000;
950 		break;
951 	case 5:
952 		cookie = 0xF000;
953 		break;
954 	}
955 	B43legacy_WARN_ON(!(((u16)slot & 0xF000) == 0x0000));
956 	cookie |= (u16)slot;
957 
958 	return cookie;
959 }
960 
961 /* Inspect a cookie and find out to which controller/slot it belongs. */
962 static
963 struct b43legacy_dmaring *parse_cookie(struct b43legacy_wldev *dev,
964 				      u16 cookie, int *slot)
965 {
966 	struct b43legacy_dma *dma = &dev->dma;
967 	struct b43legacy_dmaring *ring = NULL;
968 
969 	switch (cookie & 0xF000) {
970 	case 0xA000:
971 		ring = dma->tx_ring0;
972 		break;
973 	case 0xB000:
974 		ring = dma->tx_ring1;
975 		break;
976 	case 0xC000:
977 		ring = dma->tx_ring2;
978 		break;
979 	case 0xD000:
980 		ring = dma->tx_ring3;
981 		break;
982 	case 0xE000:
983 		ring = dma->tx_ring4;
984 		break;
985 	case 0xF000:
986 		ring = dma->tx_ring5;
987 		break;
988 	default:
989 		B43legacy_WARN_ON(1);
990 	}
991 	*slot = (cookie & 0x0FFF);
992 	B43legacy_WARN_ON(!(ring && *slot >= 0 && *slot < ring->nr_slots));
993 
994 	return ring;
995 }
996 
997 static int dma_tx_fragment(struct b43legacy_dmaring *ring,
998 			    struct sk_buff **in_skb)
999 {
1000 	struct sk_buff *skb = *in_skb;
1001 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1002 	u8 *header;
1003 	int slot, old_top_slot, old_used_slots;
1004 	int err;
1005 	struct b43legacy_dmadesc32 *desc;
1006 	struct b43legacy_dmadesc_meta *meta;
1007 	struct b43legacy_dmadesc_meta *meta_hdr;
1008 	struct sk_buff *bounce_skb;
1009 
1010 #define SLOTS_PER_PACKET  2
1011 	B43legacy_WARN_ON(skb_shinfo(skb)->nr_frags != 0);
1012 
1013 	old_top_slot = ring->current_slot;
1014 	old_used_slots = ring->used_slots;
1015 
1016 	/* Get a slot for the header. */
1017 	slot = request_slot(ring);
1018 	desc = op32_idx2desc(ring, slot, &meta_hdr);
1019 	memset(meta_hdr, 0, sizeof(*meta_hdr));
1020 
1021 	header = &(ring->txhdr_cache[slot * sizeof(
1022 			       struct b43legacy_txhdr_fw3)]);
1023 	err = b43legacy_generate_txhdr(ring->dev, header,
1024 				 skb->data, skb->len, info,
1025 				 generate_cookie(ring, slot));
1026 	if (unlikely(err)) {
1027 		ring->current_slot = old_top_slot;
1028 		ring->used_slots = old_used_slots;
1029 		return err;
1030 	}
1031 
1032 	meta_hdr->dmaaddr = map_descbuffer(ring, (unsigned char *)header,
1033 					   sizeof(struct b43legacy_txhdr_fw3), 1);
1034 	if (b43legacy_dma_mapping_error(ring, meta_hdr->dmaaddr,
1035 					sizeof(struct b43legacy_txhdr_fw3), 1)) {
1036 		ring->current_slot = old_top_slot;
1037 		ring->used_slots = old_used_slots;
1038 		return -EIO;
1039 	}
1040 	op32_fill_descriptor(ring, desc, meta_hdr->dmaaddr,
1041 			     sizeof(struct b43legacy_txhdr_fw3), 1, 0, 0);
1042 
1043 	/* Get a slot for the payload. */
1044 	slot = request_slot(ring);
1045 	desc = op32_idx2desc(ring, slot, &meta);
1046 	memset(meta, 0, sizeof(*meta));
1047 
1048 	meta->skb = skb;
1049 	meta->is_last_fragment = true;
1050 
1051 	meta->dmaaddr = map_descbuffer(ring, skb->data, skb->len, 1);
1052 	/* create a bounce buffer in zone_dma on mapping failure. */
1053 	if (b43legacy_dma_mapping_error(ring, meta->dmaaddr, skb->len, 1)) {
1054 		bounce_skb = alloc_skb(skb->len, GFP_KERNEL | GFP_DMA);
1055 		if (!bounce_skb) {
1056 			ring->current_slot = old_top_slot;
1057 			ring->used_slots = old_used_slots;
1058 			err = -ENOMEM;
1059 			goto out_unmap_hdr;
1060 		}
1061 
1062 		skb_put_data(bounce_skb, skb->data, skb->len);
1063 		memcpy(bounce_skb->cb, skb->cb, sizeof(skb->cb));
1064 		bounce_skb->dev = skb->dev;
1065 		skb_set_queue_mapping(bounce_skb, skb_get_queue_mapping(skb));
1066 		info = IEEE80211_SKB_CB(bounce_skb);
1067 
1068 		dev_kfree_skb_any(skb);
1069 		skb = bounce_skb;
1070 		*in_skb = bounce_skb;
1071 		meta->skb = skb;
1072 		meta->dmaaddr = map_descbuffer(ring, skb->data, skb->len, 1);
1073 		if (b43legacy_dma_mapping_error(ring, meta->dmaaddr, skb->len, 1)) {
1074 			ring->current_slot = old_top_slot;
1075 			ring->used_slots = old_used_slots;
1076 			err = -EIO;
1077 			goto out_free_bounce;
1078 		}
1079 	}
1080 
1081 	op32_fill_descriptor(ring, desc, meta->dmaaddr,
1082 			     skb->len, 0, 1, 1);
1083 
1084 	wmb();	/* previous stuff MUST be done */
1085 	/* Now transfer the whole frame. */
1086 	op32_poke_tx(ring, next_slot(ring, slot));
1087 	return 0;
1088 
1089 out_free_bounce:
1090 	dev_kfree_skb_any(skb);
1091 out_unmap_hdr:
1092 	unmap_descbuffer(ring, meta_hdr->dmaaddr,
1093 			 sizeof(struct b43legacy_txhdr_fw3), 1);
1094 	return err;
1095 }
1096 
1097 static inline
1098 int should_inject_overflow(struct b43legacy_dmaring *ring)
1099 {
1100 #ifdef CONFIG_B43LEGACY_DEBUG
1101 	if (unlikely(b43legacy_debug(ring->dev,
1102 				     B43legacy_DBG_DMAOVERFLOW))) {
1103 		/* Check if we should inject another ringbuffer overflow
1104 		 * to test handling of this situation in the stack. */
1105 		unsigned long next_overflow;
1106 
1107 		next_overflow = ring->last_injected_overflow + HZ;
1108 		if (time_after(jiffies, next_overflow)) {
1109 			ring->last_injected_overflow = jiffies;
1110 			b43legacydbg(ring->dev->wl,
1111 			       "Injecting TX ring overflow on "
1112 			       "DMA controller %d\n", ring->index);
1113 			return 1;
1114 		}
1115 	}
1116 #endif /* CONFIG_B43LEGACY_DEBUG */
1117 	return 0;
1118 }
1119 
1120 int b43legacy_dma_tx(struct b43legacy_wldev *dev,
1121 		     struct sk_buff *skb)
1122 {
1123 	struct b43legacy_dmaring *ring;
1124 	int err = 0;
1125 
1126 	ring = priority_to_txring(dev, skb_get_queue_mapping(skb));
1127 	B43legacy_WARN_ON(!ring->tx);
1128 
1129 	if (unlikely(ring->stopped)) {
1130 		/* We get here only because of a bug in mac80211.
1131 		 * Because of a race, one packet may be queued after
1132 		 * the queue is stopped, thus we got called when we shouldn't.
1133 		 * For now, just refuse the transmit. */
1134 		if (b43legacy_debug(dev, B43legacy_DBG_DMAVERBOSE))
1135 			b43legacyerr(dev->wl, "Packet after queue stopped\n");
1136 		return -ENOSPC;
1137 	}
1138 
1139 	if (WARN_ON(free_slots(ring) < SLOTS_PER_PACKET)) {
1140 		/* If we get here, we have a real error with the queue
1141 		 * full, but queues not stopped. */
1142 		b43legacyerr(dev->wl, "DMA queue overflow\n");
1143 		return -ENOSPC;
1144 	}
1145 
1146 	/* dma_tx_fragment might reallocate the skb, so invalidate pointers pointing
1147 	 * into the skb data or cb now. */
1148 	err = dma_tx_fragment(ring, &skb);
1149 	if (unlikely(err == -ENOKEY)) {
1150 		/* Drop this packet, as we don't have the encryption key
1151 		 * anymore and must not transmit it unencrypted. */
1152 		dev_kfree_skb_any(skb);
1153 		return 0;
1154 	}
1155 	if (unlikely(err)) {
1156 		b43legacyerr(dev->wl, "DMA tx mapping failure\n");
1157 		return err;
1158 	}
1159 	if ((free_slots(ring) < SLOTS_PER_PACKET) ||
1160 	    should_inject_overflow(ring)) {
1161 		/* This TX ring is full. */
1162 		unsigned int skb_mapping = skb_get_queue_mapping(skb);
1163 		ieee80211_stop_queue(dev->wl->hw, skb_mapping);
1164 		dev->wl->tx_queue_stopped[skb_mapping] = 1;
1165 		ring->stopped = true;
1166 		if (b43legacy_debug(dev, B43legacy_DBG_DMAVERBOSE))
1167 			b43legacydbg(dev->wl, "Stopped TX ring %d\n",
1168 			       ring->index);
1169 	}
1170 	return err;
1171 }
1172 
1173 void b43legacy_dma_handle_txstatus(struct b43legacy_wldev *dev,
1174 				 const struct b43legacy_txstatus *status)
1175 {
1176 	struct b43legacy_dmaring *ring;
1177 	struct b43legacy_dmadesc_meta *meta;
1178 	int retry_limit;
1179 	int slot;
1180 	int firstused;
1181 
1182 	ring = parse_cookie(dev, status->cookie, &slot);
1183 	if (unlikely(!ring))
1184 		return;
1185 	B43legacy_WARN_ON(!ring->tx);
1186 
1187 	/* Sanity check: TX packets are processed in-order on one ring.
1188 	 * Check if the slot deduced from the cookie really is the first
1189 	 * used slot. */
1190 	firstused = ring->current_slot - ring->used_slots + 1;
1191 	if (firstused < 0)
1192 		firstused = ring->nr_slots + firstused;
1193 	if (unlikely(slot != firstused)) {
1194 		/* This possibly is a firmware bug and will result in
1195 		 * malfunction, memory leaks and/or stall of DMA functionality.
1196 		 */
1197 		b43legacydbg(dev->wl, "Out of order TX status report on DMA "
1198 			     "ring %d. Expected %d, but got %d\n",
1199 			     ring->index, firstused, slot);
1200 		return;
1201 	}
1202 
1203 	while (1) {
1204 		B43legacy_WARN_ON(!(slot >= 0 && slot < ring->nr_slots));
1205 		op32_idx2desc(ring, slot, &meta);
1206 
1207 		if (meta->skb)
1208 			unmap_descbuffer(ring, meta->dmaaddr,
1209 					 meta->skb->len, 1);
1210 		else
1211 			unmap_descbuffer(ring, meta->dmaaddr,
1212 					 sizeof(struct b43legacy_txhdr_fw3),
1213 					 1);
1214 
1215 		if (meta->is_last_fragment) {
1216 			struct ieee80211_tx_info *info;
1217 			BUG_ON(!meta->skb);
1218 			info = IEEE80211_SKB_CB(meta->skb);
1219 
1220 			/* preserve the confiured retry limit before clearing the status
1221 			 * The xmit function has overwritten the rc's value with the actual
1222 			 * retry limit done by the hardware */
1223 			retry_limit = info->status.rates[0].count;
1224 			ieee80211_tx_info_clear_status(info);
1225 
1226 			if (status->acked)
1227 				info->flags |= IEEE80211_TX_STAT_ACK;
1228 
1229 			if (status->rts_count > dev->wl->hw->conf.short_frame_max_tx_count) {
1230 				/*
1231 				 * If the short retries (RTS, not data frame) have exceeded
1232 				 * the limit, the hw will not have tried the selected rate,
1233 				 * but will have used the fallback rate instead.
1234 				 * Don't let the rate control count attempts for the selected
1235 				 * rate in this case, otherwise the statistics will be off.
1236 				 */
1237 				info->status.rates[0].count = 0;
1238 				info->status.rates[1].count = status->frame_count;
1239 			} else {
1240 				if (status->frame_count > retry_limit) {
1241 					info->status.rates[0].count = retry_limit;
1242 					info->status.rates[1].count = status->frame_count -
1243 							retry_limit;
1244 
1245 				} else {
1246 					info->status.rates[0].count = status->frame_count;
1247 					info->status.rates[1].idx = -1;
1248 				}
1249 			}
1250 
1251 			/* Call back to inform the ieee80211 subsystem about the
1252 			 * status of the transmission.
1253 			 * Some fields of txstat are already filled in dma_tx().
1254 			 */
1255 			ieee80211_tx_status_irqsafe(dev->wl->hw, meta->skb);
1256 			/* skb is freed by ieee80211_tx_status_irqsafe() */
1257 			meta->skb = NULL;
1258 		} else {
1259 			/* No need to call free_descriptor_buffer here, as
1260 			 * this is only the txhdr, which is not allocated.
1261 			 */
1262 			B43legacy_WARN_ON(meta->skb != NULL);
1263 		}
1264 
1265 		/* Everything unmapped and free'd. So it's not used anymore. */
1266 		ring->used_slots--;
1267 
1268 		if (meta->is_last_fragment)
1269 			break;
1270 		slot = next_slot(ring, slot);
1271 	}
1272 	dev->stats.last_tx = jiffies;
1273 	if (ring->stopped) {
1274 		B43legacy_WARN_ON(free_slots(ring) < SLOTS_PER_PACKET);
1275 		ring->stopped = false;
1276 	}
1277 
1278 	if (dev->wl->tx_queue_stopped[ring->queue_prio]) {
1279 		dev->wl->tx_queue_stopped[ring->queue_prio] = 0;
1280 	} else {
1281 		/* If the driver queue is running wake the corresponding
1282 		 * mac80211 queue. */
1283 		ieee80211_wake_queue(dev->wl->hw, ring->queue_prio);
1284 		if (b43legacy_debug(dev, B43legacy_DBG_DMAVERBOSE))
1285 			b43legacydbg(dev->wl, "Woke up TX ring %d\n",
1286 				     ring->index);
1287 	}
1288 	/* Add work to the queue. */
1289 	ieee80211_queue_work(dev->wl->hw, &dev->wl->tx_work);
1290 }
1291 
1292 static void dma_rx(struct b43legacy_dmaring *ring,
1293 		   int *slot)
1294 {
1295 	struct b43legacy_dmadesc32 *desc;
1296 	struct b43legacy_dmadesc_meta *meta;
1297 	struct b43legacy_rxhdr_fw3 *rxhdr;
1298 	struct sk_buff *skb;
1299 	u16 len;
1300 	int err;
1301 	dma_addr_t dmaaddr;
1302 
1303 	desc = op32_idx2desc(ring, *slot, &meta);
1304 
1305 	sync_descbuffer_for_cpu(ring, meta->dmaaddr, ring->rx_buffersize);
1306 	skb = meta->skb;
1307 
1308 	if (ring->index == 3) {
1309 		/* We received an xmit status. */
1310 		struct b43legacy_hwtxstatus *hw =
1311 				(struct b43legacy_hwtxstatus *)skb->data;
1312 		int i = 0;
1313 
1314 		while (hw->cookie == 0) {
1315 			if (i > 100)
1316 				break;
1317 			i++;
1318 			udelay(2);
1319 			barrier();
1320 		}
1321 		b43legacy_handle_hwtxstatus(ring->dev, hw);
1322 		/* recycle the descriptor buffer. */
1323 		sync_descbuffer_for_device(ring, meta->dmaaddr,
1324 					   ring->rx_buffersize);
1325 
1326 		return;
1327 	}
1328 	rxhdr = (struct b43legacy_rxhdr_fw3 *)skb->data;
1329 	len = le16_to_cpu(rxhdr->frame_len);
1330 	if (len == 0) {
1331 		int i = 0;
1332 
1333 		do {
1334 			udelay(2);
1335 			barrier();
1336 			len = le16_to_cpu(rxhdr->frame_len);
1337 		} while (len == 0 && i++ < 5);
1338 		if (unlikely(len == 0)) {
1339 			/* recycle the descriptor buffer. */
1340 			sync_descbuffer_for_device(ring, meta->dmaaddr,
1341 						   ring->rx_buffersize);
1342 			goto drop;
1343 		}
1344 	}
1345 	if (unlikely(len > ring->rx_buffersize)) {
1346 		/* The data did not fit into one descriptor buffer
1347 		 * and is split over multiple buffers.
1348 		 * This should never happen, as we try to allocate buffers
1349 		 * big enough. So simply ignore this packet.
1350 		 */
1351 		int cnt = 0;
1352 		s32 tmp = len;
1353 
1354 		while (1) {
1355 			desc = op32_idx2desc(ring, *slot, &meta);
1356 			/* recycle the descriptor buffer. */
1357 			sync_descbuffer_for_device(ring, meta->dmaaddr,
1358 						   ring->rx_buffersize);
1359 			*slot = next_slot(ring, *slot);
1360 			cnt++;
1361 			tmp -= ring->rx_buffersize;
1362 			if (tmp <= 0)
1363 				break;
1364 		}
1365 		b43legacyerr(ring->dev->wl, "DMA RX buffer too small "
1366 		       "(len: %u, buffer: %u, nr-dropped: %d)\n",
1367 		       len, ring->rx_buffersize, cnt);
1368 		goto drop;
1369 	}
1370 
1371 	dmaaddr = meta->dmaaddr;
1372 	err = setup_rx_descbuffer(ring, desc, meta, GFP_ATOMIC);
1373 	if (unlikely(err)) {
1374 		b43legacydbg(ring->dev->wl, "DMA RX: setup_rx_descbuffer()"
1375 			     " failed\n");
1376 		sync_descbuffer_for_device(ring, dmaaddr,
1377 					   ring->rx_buffersize);
1378 		goto drop;
1379 	}
1380 
1381 	unmap_descbuffer(ring, dmaaddr, ring->rx_buffersize, 0);
1382 	skb_put(skb, len + ring->frameoffset);
1383 	skb_pull(skb, ring->frameoffset);
1384 
1385 	b43legacy_rx(ring->dev, skb, rxhdr);
1386 drop:
1387 	return;
1388 }
1389 
1390 void b43legacy_dma_rx(struct b43legacy_dmaring *ring)
1391 {
1392 	int slot;
1393 	int current_slot;
1394 	int used_slots = 0;
1395 
1396 	B43legacy_WARN_ON(ring->tx);
1397 	current_slot = op32_get_current_rxslot(ring);
1398 	B43legacy_WARN_ON(!(current_slot >= 0 && current_slot <
1399 			   ring->nr_slots));
1400 
1401 	slot = ring->current_slot;
1402 	for (; slot != current_slot; slot = next_slot(ring, slot)) {
1403 		dma_rx(ring, &slot);
1404 		update_max_used_slots(ring, ++used_slots);
1405 	}
1406 	op32_set_current_rxslot(ring, slot);
1407 	ring->current_slot = slot;
1408 }
1409 
1410 static void b43legacy_dma_tx_suspend_ring(struct b43legacy_dmaring *ring)
1411 {
1412 	B43legacy_WARN_ON(!ring->tx);
1413 	op32_tx_suspend(ring);
1414 }
1415 
1416 static void b43legacy_dma_tx_resume_ring(struct b43legacy_dmaring *ring)
1417 {
1418 	B43legacy_WARN_ON(!ring->tx);
1419 	op32_tx_resume(ring);
1420 }
1421 
1422 void b43legacy_dma_tx_suspend(struct b43legacy_wldev *dev)
1423 {
1424 	b43legacy_power_saving_ctl_bits(dev, -1, 1);
1425 	b43legacy_dma_tx_suspend_ring(dev->dma.tx_ring0);
1426 	b43legacy_dma_tx_suspend_ring(dev->dma.tx_ring1);
1427 	b43legacy_dma_tx_suspend_ring(dev->dma.tx_ring2);
1428 	b43legacy_dma_tx_suspend_ring(dev->dma.tx_ring3);
1429 	b43legacy_dma_tx_suspend_ring(dev->dma.tx_ring4);
1430 	b43legacy_dma_tx_suspend_ring(dev->dma.tx_ring5);
1431 }
1432 
1433 void b43legacy_dma_tx_resume(struct b43legacy_wldev *dev)
1434 {
1435 	b43legacy_dma_tx_resume_ring(dev->dma.tx_ring5);
1436 	b43legacy_dma_tx_resume_ring(dev->dma.tx_ring4);
1437 	b43legacy_dma_tx_resume_ring(dev->dma.tx_ring3);
1438 	b43legacy_dma_tx_resume_ring(dev->dma.tx_ring2);
1439 	b43legacy_dma_tx_resume_ring(dev->dma.tx_ring1);
1440 	b43legacy_dma_tx_resume_ring(dev->dma.tx_ring0);
1441 	b43legacy_power_saving_ctl_bits(dev, -1, -1);
1442 }
1443