xref: /linux/drivers/dma/mv_xor.c (revision c4ee0af3fa0dc65f690fc908f02b8355f9576ea0)
1 /*
2  * offload engine driver for the Marvell XOR engine
3  * Copyright (C) 2007, 2008, Marvell International Ltd.
4  *
5  * This program is free software; you can redistribute it and/or modify it
6  * under the terms and conditions of the GNU General Public License,
7  * version 2, as published by the Free Software Foundation.
8  *
9  * This program is distributed in the hope it will be useful, but WITHOUT
10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
12  * more details.
13  *
14  * You should have received a copy of the GNU General Public License along with
15  * this program; if not, write to the Free Software Foundation, Inc.,
16  * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
17  */
18 
19 #include <linux/init.h>
20 #include <linux/module.h>
21 #include <linux/slab.h>
22 #include <linux/delay.h>
23 #include <linux/dma-mapping.h>
24 #include <linux/spinlock.h>
25 #include <linux/interrupt.h>
26 #include <linux/platform_device.h>
27 #include <linux/memory.h>
28 #include <linux/clk.h>
29 #include <linux/of.h>
30 #include <linux/of_irq.h>
31 #include <linux/irqdomain.h>
32 #include <linux/platform_data/dma-mv_xor.h>
33 
34 #include "dmaengine.h"
35 #include "mv_xor.h"
36 
37 static void mv_xor_issue_pending(struct dma_chan *chan);
38 
39 #define to_mv_xor_chan(chan)		\
40 	container_of(chan, struct mv_xor_chan, dmachan)
41 
42 #define to_mv_xor_slot(tx)		\
43 	container_of(tx, struct mv_xor_desc_slot, async_tx)
44 
45 #define mv_chan_to_devp(chan)           \
46 	((chan)->dmadev.dev)
47 
48 static void mv_desc_init(struct mv_xor_desc_slot *desc, unsigned long flags)
49 {
50 	struct mv_xor_desc *hw_desc = desc->hw_desc;
51 
52 	hw_desc->status = (1 << 31);
53 	hw_desc->phy_next_desc = 0;
54 	hw_desc->desc_command = (1 << 31);
55 }
56 
57 static void mv_desc_set_byte_count(struct mv_xor_desc_slot *desc,
58 				   u32 byte_count)
59 {
60 	struct mv_xor_desc *hw_desc = desc->hw_desc;
61 	hw_desc->byte_count = byte_count;
62 }
63 
64 static void mv_desc_set_next_desc(struct mv_xor_desc_slot *desc,
65 				  u32 next_desc_addr)
66 {
67 	struct mv_xor_desc *hw_desc = desc->hw_desc;
68 	BUG_ON(hw_desc->phy_next_desc);
69 	hw_desc->phy_next_desc = next_desc_addr;
70 }
71 
72 static void mv_desc_clear_next_desc(struct mv_xor_desc_slot *desc)
73 {
74 	struct mv_xor_desc *hw_desc = desc->hw_desc;
75 	hw_desc->phy_next_desc = 0;
76 }
77 
78 static void mv_desc_set_dest_addr(struct mv_xor_desc_slot *desc,
79 				  dma_addr_t addr)
80 {
81 	struct mv_xor_desc *hw_desc = desc->hw_desc;
82 	hw_desc->phy_dest_addr = addr;
83 }
84 
85 static int mv_chan_memset_slot_count(size_t len)
86 {
87 	return 1;
88 }
89 
90 #define mv_chan_memcpy_slot_count(c) mv_chan_memset_slot_count(c)
91 
92 static void mv_desc_set_src_addr(struct mv_xor_desc_slot *desc,
93 				 int index, dma_addr_t addr)
94 {
95 	struct mv_xor_desc *hw_desc = desc->hw_desc;
96 	hw_desc->phy_src_addr[mv_phy_src_idx(index)] = addr;
97 	if (desc->type == DMA_XOR)
98 		hw_desc->desc_command |= (1 << index);
99 }
100 
101 static u32 mv_chan_get_current_desc(struct mv_xor_chan *chan)
102 {
103 	return readl_relaxed(XOR_CURR_DESC(chan));
104 }
105 
106 static void mv_chan_set_next_descriptor(struct mv_xor_chan *chan,
107 					u32 next_desc_addr)
108 {
109 	writel_relaxed(next_desc_addr, XOR_NEXT_DESC(chan));
110 }
111 
112 static void mv_chan_unmask_interrupts(struct mv_xor_chan *chan)
113 {
114 	u32 val = readl_relaxed(XOR_INTR_MASK(chan));
115 	val |= XOR_INTR_MASK_VALUE << (chan->idx * 16);
116 	writel_relaxed(val, XOR_INTR_MASK(chan));
117 }
118 
119 static u32 mv_chan_get_intr_cause(struct mv_xor_chan *chan)
120 {
121 	u32 intr_cause = readl_relaxed(XOR_INTR_CAUSE(chan));
122 	intr_cause = (intr_cause >> (chan->idx * 16)) & 0xFFFF;
123 	return intr_cause;
124 }
125 
126 static int mv_is_err_intr(u32 intr_cause)
127 {
128 	if (intr_cause & ((1<<4)|(1<<5)|(1<<6)|(1<<7)|(1<<8)|(1<<9)))
129 		return 1;
130 
131 	return 0;
132 }
133 
134 static void mv_xor_device_clear_eoc_cause(struct mv_xor_chan *chan)
135 {
136 	u32 val = ~(1 << (chan->idx * 16));
137 	dev_dbg(mv_chan_to_devp(chan), "%s, val 0x%08x\n", __func__, val);
138 	writel_relaxed(val, XOR_INTR_CAUSE(chan));
139 }
140 
141 static void mv_xor_device_clear_err_status(struct mv_xor_chan *chan)
142 {
143 	u32 val = 0xFFFF0000 >> (chan->idx * 16);
144 	writel_relaxed(val, XOR_INTR_CAUSE(chan));
145 }
146 
147 static int mv_can_chain(struct mv_xor_desc_slot *desc)
148 {
149 	struct mv_xor_desc_slot *chain_old_tail = list_entry(
150 		desc->chain_node.prev, struct mv_xor_desc_slot, chain_node);
151 
152 	if (chain_old_tail->type != desc->type)
153 		return 0;
154 
155 	return 1;
156 }
157 
158 static void mv_set_mode(struct mv_xor_chan *chan,
159 			       enum dma_transaction_type type)
160 {
161 	u32 op_mode;
162 	u32 config = readl_relaxed(XOR_CONFIG(chan));
163 
164 	switch (type) {
165 	case DMA_XOR:
166 		op_mode = XOR_OPERATION_MODE_XOR;
167 		break;
168 	case DMA_MEMCPY:
169 		op_mode = XOR_OPERATION_MODE_MEMCPY;
170 		break;
171 	default:
172 		dev_err(mv_chan_to_devp(chan),
173 			"error: unsupported operation %d\n",
174 			type);
175 		BUG();
176 		return;
177 	}
178 
179 	config &= ~0x7;
180 	config |= op_mode;
181 
182 #if defined(__BIG_ENDIAN)
183 	config |= XOR_DESCRIPTOR_SWAP;
184 #else
185 	config &= ~XOR_DESCRIPTOR_SWAP;
186 #endif
187 
188 	writel_relaxed(config, XOR_CONFIG(chan));
189 	chan->current_type = type;
190 }
191 
192 static void mv_chan_activate(struct mv_xor_chan *chan)
193 {
194 	u32 activation;
195 
196 	dev_dbg(mv_chan_to_devp(chan), " activate chan.\n");
197 	activation = readl_relaxed(XOR_ACTIVATION(chan));
198 	activation |= 0x1;
199 	writel_relaxed(activation, XOR_ACTIVATION(chan));
200 }
201 
202 static char mv_chan_is_busy(struct mv_xor_chan *chan)
203 {
204 	u32 state = readl_relaxed(XOR_ACTIVATION(chan));
205 
206 	state = (state >> 4) & 0x3;
207 
208 	return (state == 1) ? 1 : 0;
209 }
210 
211 static int mv_chan_xor_slot_count(size_t len, int src_cnt)
212 {
213 	return 1;
214 }
215 
216 /**
217  * mv_xor_free_slots - flags descriptor slots for reuse
218  * @slot: Slot to free
219  * Caller must hold &mv_chan->lock while calling this function
220  */
221 static void mv_xor_free_slots(struct mv_xor_chan *mv_chan,
222 			      struct mv_xor_desc_slot *slot)
223 {
224 	dev_dbg(mv_chan_to_devp(mv_chan), "%s %d slot %p\n",
225 		__func__, __LINE__, slot);
226 
227 	slot->slots_per_op = 0;
228 
229 }
230 
231 /*
232  * mv_xor_start_new_chain - program the engine to operate on new chain headed by
233  * sw_desc
234  * Caller must hold &mv_chan->lock while calling this function
235  */
236 static void mv_xor_start_new_chain(struct mv_xor_chan *mv_chan,
237 				   struct mv_xor_desc_slot *sw_desc)
238 {
239 	dev_dbg(mv_chan_to_devp(mv_chan), "%s %d: sw_desc %p\n",
240 		__func__, __LINE__, sw_desc);
241 	if (sw_desc->type != mv_chan->current_type)
242 		mv_set_mode(mv_chan, sw_desc->type);
243 
244 	/* set the hardware chain */
245 	mv_chan_set_next_descriptor(mv_chan, sw_desc->async_tx.phys);
246 
247 	mv_chan->pending += sw_desc->slot_cnt;
248 	mv_xor_issue_pending(&mv_chan->dmachan);
249 }
250 
251 static dma_cookie_t
252 mv_xor_run_tx_complete_actions(struct mv_xor_desc_slot *desc,
253 	struct mv_xor_chan *mv_chan, dma_cookie_t cookie)
254 {
255 	BUG_ON(desc->async_tx.cookie < 0);
256 
257 	if (desc->async_tx.cookie > 0) {
258 		cookie = desc->async_tx.cookie;
259 
260 		/* call the callback (must not sleep or submit new
261 		 * operations to this channel)
262 		 */
263 		if (desc->async_tx.callback)
264 			desc->async_tx.callback(
265 				desc->async_tx.callback_param);
266 
267 		dma_descriptor_unmap(&desc->async_tx);
268 		if (desc->group_head)
269 			desc->group_head = NULL;
270 	}
271 
272 	/* run dependent operations */
273 	dma_run_dependencies(&desc->async_tx);
274 
275 	return cookie;
276 }
277 
278 static int
279 mv_xor_clean_completed_slots(struct mv_xor_chan *mv_chan)
280 {
281 	struct mv_xor_desc_slot *iter, *_iter;
282 
283 	dev_dbg(mv_chan_to_devp(mv_chan), "%s %d\n", __func__, __LINE__);
284 	list_for_each_entry_safe(iter, _iter, &mv_chan->completed_slots,
285 				 completed_node) {
286 
287 		if (async_tx_test_ack(&iter->async_tx)) {
288 			list_del(&iter->completed_node);
289 			mv_xor_free_slots(mv_chan, iter);
290 		}
291 	}
292 	return 0;
293 }
294 
295 static int
296 mv_xor_clean_slot(struct mv_xor_desc_slot *desc,
297 	struct mv_xor_chan *mv_chan)
298 {
299 	dev_dbg(mv_chan_to_devp(mv_chan), "%s %d: desc %p flags %d\n",
300 		__func__, __LINE__, desc, desc->async_tx.flags);
301 	list_del(&desc->chain_node);
302 	/* the client is allowed to attach dependent operations
303 	 * until 'ack' is set
304 	 */
305 	if (!async_tx_test_ack(&desc->async_tx)) {
306 		/* move this slot to the completed_slots */
307 		list_add_tail(&desc->completed_node, &mv_chan->completed_slots);
308 		return 0;
309 	}
310 
311 	mv_xor_free_slots(mv_chan, desc);
312 	return 0;
313 }
314 
315 static void __mv_xor_slot_cleanup(struct mv_xor_chan *mv_chan)
316 {
317 	struct mv_xor_desc_slot *iter, *_iter;
318 	dma_cookie_t cookie = 0;
319 	int busy = mv_chan_is_busy(mv_chan);
320 	u32 current_desc = mv_chan_get_current_desc(mv_chan);
321 	int seen_current = 0;
322 
323 	dev_dbg(mv_chan_to_devp(mv_chan), "%s %d\n", __func__, __LINE__);
324 	dev_dbg(mv_chan_to_devp(mv_chan), "current_desc %x\n", current_desc);
325 	mv_xor_clean_completed_slots(mv_chan);
326 
327 	/* free completed slots from the chain starting with
328 	 * the oldest descriptor
329 	 */
330 
331 	list_for_each_entry_safe(iter, _iter, &mv_chan->chain,
332 					chain_node) {
333 		prefetch(_iter);
334 		prefetch(&_iter->async_tx);
335 
336 		/* do not advance past the current descriptor loaded into the
337 		 * hardware channel, subsequent descriptors are either in
338 		 * process or have not been submitted
339 		 */
340 		if (seen_current)
341 			break;
342 
343 		/* stop the search if we reach the current descriptor and the
344 		 * channel is busy
345 		 */
346 		if (iter->async_tx.phys == current_desc) {
347 			seen_current = 1;
348 			if (busy)
349 				break;
350 		}
351 
352 		cookie = mv_xor_run_tx_complete_actions(iter, mv_chan, cookie);
353 
354 		if (mv_xor_clean_slot(iter, mv_chan))
355 			break;
356 	}
357 
358 	if ((busy == 0) && !list_empty(&mv_chan->chain)) {
359 		struct mv_xor_desc_slot *chain_head;
360 		chain_head = list_entry(mv_chan->chain.next,
361 					struct mv_xor_desc_slot,
362 					chain_node);
363 
364 		mv_xor_start_new_chain(mv_chan, chain_head);
365 	}
366 
367 	if (cookie > 0)
368 		mv_chan->dmachan.completed_cookie = cookie;
369 }
370 
371 static void
372 mv_xor_slot_cleanup(struct mv_xor_chan *mv_chan)
373 {
374 	spin_lock_bh(&mv_chan->lock);
375 	__mv_xor_slot_cleanup(mv_chan);
376 	spin_unlock_bh(&mv_chan->lock);
377 }
378 
379 static void mv_xor_tasklet(unsigned long data)
380 {
381 	struct mv_xor_chan *chan = (struct mv_xor_chan *) data;
382 	mv_xor_slot_cleanup(chan);
383 }
384 
385 static struct mv_xor_desc_slot *
386 mv_xor_alloc_slots(struct mv_xor_chan *mv_chan, int num_slots,
387 		    int slots_per_op)
388 {
389 	struct mv_xor_desc_slot *iter, *_iter, *alloc_start = NULL;
390 	LIST_HEAD(chain);
391 	int slots_found, retry = 0;
392 
393 	/* start search from the last allocated descrtiptor
394 	 * if a contiguous allocation can not be found start searching
395 	 * from the beginning of the list
396 	 */
397 retry:
398 	slots_found = 0;
399 	if (retry == 0)
400 		iter = mv_chan->last_used;
401 	else
402 		iter = list_entry(&mv_chan->all_slots,
403 			struct mv_xor_desc_slot,
404 			slot_node);
405 
406 	list_for_each_entry_safe_continue(
407 		iter, _iter, &mv_chan->all_slots, slot_node) {
408 		prefetch(_iter);
409 		prefetch(&_iter->async_tx);
410 		if (iter->slots_per_op) {
411 			/* give up after finding the first busy slot
412 			 * on the second pass through the list
413 			 */
414 			if (retry)
415 				break;
416 
417 			slots_found = 0;
418 			continue;
419 		}
420 
421 		/* start the allocation if the slot is correctly aligned */
422 		if (!slots_found++)
423 			alloc_start = iter;
424 
425 		if (slots_found == num_slots) {
426 			struct mv_xor_desc_slot *alloc_tail = NULL;
427 			struct mv_xor_desc_slot *last_used = NULL;
428 			iter = alloc_start;
429 			while (num_slots) {
430 				int i;
431 
432 				/* pre-ack all but the last descriptor */
433 				async_tx_ack(&iter->async_tx);
434 
435 				list_add_tail(&iter->chain_node, &chain);
436 				alloc_tail = iter;
437 				iter->async_tx.cookie = 0;
438 				iter->slot_cnt = num_slots;
439 				iter->xor_check_result = NULL;
440 				for (i = 0; i < slots_per_op; i++) {
441 					iter->slots_per_op = slots_per_op - i;
442 					last_used = iter;
443 					iter = list_entry(iter->slot_node.next,
444 						struct mv_xor_desc_slot,
445 						slot_node);
446 				}
447 				num_slots -= slots_per_op;
448 			}
449 			alloc_tail->group_head = alloc_start;
450 			alloc_tail->async_tx.cookie = -EBUSY;
451 			list_splice(&chain, &alloc_tail->tx_list);
452 			mv_chan->last_used = last_used;
453 			mv_desc_clear_next_desc(alloc_start);
454 			mv_desc_clear_next_desc(alloc_tail);
455 			return alloc_tail;
456 		}
457 	}
458 	if (!retry++)
459 		goto retry;
460 
461 	/* try to free some slots if the allocation fails */
462 	tasklet_schedule(&mv_chan->irq_tasklet);
463 
464 	return NULL;
465 }
466 
467 /************************ DMA engine API functions ****************************/
468 static dma_cookie_t
469 mv_xor_tx_submit(struct dma_async_tx_descriptor *tx)
470 {
471 	struct mv_xor_desc_slot *sw_desc = to_mv_xor_slot(tx);
472 	struct mv_xor_chan *mv_chan = to_mv_xor_chan(tx->chan);
473 	struct mv_xor_desc_slot *grp_start, *old_chain_tail;
474 	dma_cookie_t cookie;
475 	int new_hw_chain = 1;
476 
477 	dev_dbg(mv_chan_to_devp(mv_chan),
478 		"%s sw_desc %p: async_tx %p\n",
479 		__func__, sw_desc, &sw_desc->async_tx);
480 
481 	grp_start = sw_desc->group_head;
482 
483 	spin_lock_bh(&mv_chan->lock);
484 	cookie = dma_cookie_assign(tx);
485 
486 	if (list_empty(&mv_chan->chain))
487 		list_splice_init(&sw_desc->tx_list, &mv_chan->chain);
488 	else {
489 		new_hw_chain = 0;
490 
491 		old_chain_tail = list_entry(mv_chan->chain.prev,
492 					    struct mv_xor_desc_slot,
493 					    chain_node);
494 		list_splice_init(&grp_start->tx_list,
495 				 &old_chain_tail->chain_node);
496 
497 		if (!mv_can_chain(grp_start))
498 			goto submit_done;
499 
500 		dev_dbg(mv_chan_to_devp(mv_chan), "Append to last desc %x\n",
501 			old_chain_tail->async_tx.phys);
502 
503 		/* fix up the hardware chain */
504 		mv_desc_set_next_desc(old_chain_tail, grp_start->async_tx.phys);
505 
506 		/* if the channel is not busy */
507 		if (!mv_chan_is_busy(mv_chan)) {
508 			u32 current_desc = mv_chan_get_current_desc(mv_chan);
509 			/*
510 			 * and the curren desc is the end of the chain before
511 			 * the append, then we need to start the channel
512 			 */
513 			if (current_desc == old_chain_tail->async_tx.phys)
514 				new_hw_chain = 1;
515 		}
516 	}
517 
518 	if (new_hw_chain)
519 		mv_xor_start_new_chain(mv_chan, grp_start);
520 
521 submit_done:
522 	spin_unlock_bh(&mv_chan->lock);
523 
524 	return cookie;
525 }
526 
527 /* returns the number of allocated descriptors */
528 static int mv_xor_alloc_chan_resources(struct dma_chan *chan)
529 {
530 	char *hw_desc;
531 	int idx;
532 	struct mv_xor_chan *mv_chan = to_mv_xor_chan(chan);
533 	struct mv_xor_desc_slot *slot = NULL;
534 	int num_descs_in_pool = MV_XOR_POOL_SIZE/MV_XOR_SLOT_SIZE;
535 
536 	/* Allocate descriptor slots */
537 	idx = mv_chan->slots_allocated;
538 	while (idx < num_descs_in_pool) {
539 		slot = kzalloc(sizeof(*slot), GFP_KERNEL);
540 		if (!slot) {
541 			printk(KERN_INFO "MV XOR Channel only initialized"
542 				" %d descriptor slots", idx);
543 			break;
544 		}
545 		hw_desc = (char *) mv_chan->dma_desc_pool_virt;
546 		slot->hw_desc = (void *) &hw_desc[idx * MV_XOR_SLOT_SIZE];
547 
548 		dma_async_tx_descriptor_init(&slot->async_tx, chan);
549 		slot->async_tx.tx_submit = mv_xor_tx_submit;
550 		INIT_LIST_HEAD(&slot->chain_node);
551 		INIT_LIST_HEAD(&slot->slot_node);
552 		INIT_LIST_HEAD(&slot->tx_list);
553 		hw_desc = (char *) mv_chan->dma_desc_pool;
554 		slot->async_tx.phys =
555 			(dma_addr_t) &hw_desc[idx * MV_XOR_SLOT_SIZE];
556 		slot->idx = idx++;
557 
558 		spin_lock_bh(&mv_chan->lock);
559 		mv_chan->slots_allocated = idx;
560 		list_add_tail(&slot->slot_node, &mv_chan->all_slots);
561 		spin_unlock_bh(&mv_chan->lock);
562 	}
563 
564 	if (mv_chan->slots_allocated && !mv_chan->last_used)
565 		mv_chan->last_used = list_entry(mv_chan->all_slots.next,
566 					struct mv_xor_desc_slot,
567 					slot_node);
568 
569 	dev_dbg(mv_chan_to_devp(mv_chan),
570 		"allocated %d descriptor slots last_used: %p\n",
571 		mv_chan->slots_allocated, mv_chan->last_used);
572 
573 	return mv_chan->slots_allocated ? : -ENOMEM;
574 }
575 
576 static struct dma_async_tx_descriptor *
577 mv_xor_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
578 		size_t len, unsigned long flags)
579 {
580 	struct mv_xor_chan *mv_chan = to_mv_xor_chan(chan);
581 	struct mv_xor_desc_slot *sw_desc, *grp_start;
582 	int slot_cnt;
583 
584 	dev_dbg(mv_chan_to_devp(mv_chan),
585 		"%s dest: %x src %x len: %u flags: %ld\n",
586 		__func__, dest, src, len, flags);
587 	if (unlikely(len < MV_XOR_MIN_BYTE_COUNT))
588 		return NULL;
589 
590 	BUG_ON(len > MV_XOR_MAX_BYTE_COUNT);
591 
592 	spin_lock_bh(&mv_chan->lock);
593 	slot_cnt = mv_chan_memcpy_slot_count(len);
594 	sw_desc = mv_xor_alloc_slots(mv_chan, slot_cnt, 1);
595 	if (sw_desc) {
596 		sw_desc->type = DMA_MEMCPY;
597 		sw_desc->async_tx.flags = flags;
598 		grp_start = sw_desc->group_head;
599 		mv_desc_init(grp_start, flags);
600 		mv_desc_set_byte_count(grp_start, len);
601 		mv_desc_set_dest_addr(sw_desc->group_head, dest);
602 		mv_desc_set_src_addr(grp_start, 0, src);
603 		sw_desc->unmap_src_cnt = 1;
604 		sw_desc->unmap_len = len;
605 	}
606 	spin_unlock_bh(&mv_chan->lock);
607 
608 	dev_dbg(mv_chan_to_devp(mv_chan),
609 		"%s sw_desc %p async_tx %p\n",
610 		__func__, sw_desc, sw_desc ? &sw_desc->async_tx : NULL);
611 
612 	return sw_desc ? &sw_desc->async_tx : NULL;
613 }
614 
615 static struct dma_async_tx_descriptor *
616 mv_xor_prep_dma_xor(struct dma_chan *chan, dma_addr_t dest, dma_addr_t *src,
617 		    unsigned int src_cnt, size_t len, unsigned long flags)
618 {
619 	struct mv_xor_chan *mv_chan = to_mv_xor_chan(chan);
620 	struct mv_xor_desc_slot *sw_desc, *grp_start;
621 	int slot_cnt;
622 
623 	if (unlikely(len < MV_XOR_MIN_BYTE_COUNT))
624 		return NULL;
625 
626 	BUG_ON(len > MV_XOR_MAX_BYTE_COUNT);
627 
628 	dev_dbg(mv_chan_to_devp(mv_chan),
629 		"%s src_cnt: %d len: dest %x %u flags: %ld\n",
630 		__func__, src_cnt, len, dest, flags);
631 
632 	spin_lock_bh(&mv_chan->lock);
633 	slot_cnt = mv_chan_xor_slot_count(len, src_cnt);
634 	sw_desc = mv_xor_alloc_slots(mv_chan, slot_cnt, 1);
635 	if (sw_desc) {
636 		sw_desc->type = DMA_XOR;
637 		sw_desc->async_tx.flags = flags;
638 		grp_start = sw_desc->group_head;
639 		mv_desc_init(grp_start, flags);
640 		/* the byte count field is the same as in memcpy desc*/
641 		mv_desc_set_byte_count(grp_start, len);
642 		mv_desc_set_dest_addr(sw_desc->group_head, dest);
643 		sw_desc->unmap_src_cnt = src_cnt;
644 		sw_desc->unmap_len = len;
645 		while (src_cnt--)
646 			mv_desc_set_src_addr(grp_start, src_cnt, src[src_cnt]);
647 	}
648 	spin_unlock_bh(&mv_chan->lock);
649 	dev_dbg(mv_chan_to_devp(mv_chan),
650 		"%s sw_desc %p async_tx %p \n",
651 		__func__, sw_desc, &sw_desc->async_tx);
652 	return sw_desc ? &sw_desc->async_tx : NULL;
653 }
654 
655 static void mv_xor_free_chan_resources(struct dma_chan *chan)
656 {
657 	struct mv_xor_chan *mv_chan = to_mv_xor_chan(chan);
658 	struct mv_xor_desc_slot *iter, *_iter;
659 	int in_use_descs = 0;
660 
661 	mv_xor_slot_cleanup(mv_chan);
662 
663 	spin_lock_bh(&mv_chan->lock);
664 	list_for_each_entry_safe(iter, _iter, &mv_chan->chain,
665 					chain_node) {
666 		in_use_descs++;
667 		list_del(&iter->chain_node);
668 	}
669 	list_for_each_entry_safe(iter, _iter, &mv_chan->completed_slots,
670 				 completed_node) {
671 		in_use_descs++;
672 		list_del(&iter->completed_node);
673 	}
674 	list_for_each_entry_safe_reverse(
675 		iter, _iter, &mv_chan->all_slots, slot_node) {
676 		list_del(&iter->slot_node);
677 		kfree(iter);
678 		mv_chan->slots_allocated--;
679 	}
680 	mv_chan->last_used = NULL;
681 
682 	dev_dbg(mv_chan_to_devp(mv_chan), "%s slots_allocated %d\n",
683 		__func__, mv_chan->slots_allocated);
684 	spin_unlock_bh(&mv_chan->lock);
685 
686 	if (in_use_descs)
687 		dev_err(mv_chan_to_devp(mv_chan),
688 			"freeing %d in use descriptors!\n", in_use_descs);
689 }
690 
691 /**
692  * mv_xor_status - poll the status of an XOR transaction
693  * @chan: XOR channel handle
694  * @cookie: XOR transaction identifier
695  * @txstate: XOR transactions state holder (or NULL)
696  */
697 static enum dma_status mv_xor_status(struct dma_chan *chan,
698 					  dma_cookie_t cookie,
699 					  struct dma_tx_state *txstate)
700 {
701 	struct mv_xor_chan *mv_chan = to_mv_xor_chan(chan);
702 	enum dma_status ret;
703 
704 	ret = dma_cookie_status(chan, cookie, txstate);
705 	if (ret == DMA_COMPLETE) {
706 		mv_xor_clean_completed_slots(mv_chan);
707 		return ret;
708 	}
709 	mv_xor_slot_cleanup(mv_chan);
710 
711 	return dma_cookie_status(chan, cookie, txstate);
712 }
713 
714 static void mv_dump_xor_regs(struct mv_xor_chan *chan)
715 {
716 	u32 val;
717 
718 	val = readl_relaxed(XOR_CONFIG(chan));
719 	dev_err(mv_chan_to_devp(chan), "config       0x%08x\n", val);
720 
721 	val = readl_relaxed(XOR_ACTIVATION(chan));
722 	dev_err(mv_chan_to_devp(chan), "activation   0x%08x\n", val);
723 
724 	val = readl_relaxed(XOR_INTR_CAUSE(chan));
725 	dev_err(mv_chan_to_devp(chan), "intr cause   0x%08x\n", val);
726 
727 	val = readl_relaxed(XOR_INTR_MASK(chan));
728 	dev_err(mv_chan_to_devp(chan), "intr mask    0x%08x\n", val);
729 
730 	val = readl_relaxed(XOR_ERROR_CAUSE(chan));
731 	dev_err(mv_chan_to_devp(chan), "error cause  0x%08x\n", val);
732 
733 	val = readl_relaxed(XOR_ERROR_ADDR(chan));
734 	dev_err(mv_chan_to_devp(chan), "error addr   0x%08x\n", val);
735 }
736 
737 static void mv_xor_err_interrupt_handler(struct mv_xor_chan *chan,
738 					 u32 intr_cause)
739 {
740 	if (intr_cause & (1 << 4)) {
741 	     dev_dbg(mv_chan_to_devp(chan),
742 		     "ignore this error\n");
743 	     return;
744 	}
745 
746 	dev_err(mv_chan_to_devp(chan),
747 		"error on chan %d. intr cause 0x%08x\n",
748 		chan->idx, intr_cause);
749 
750 	mv_dump_xor_regs(chan);
751 	BUG();
752 }
753 
754 static irqreturn_t mv_xor_interrupt_handler(int irq, void *data)
755 {
756 	struct mv_xor_chan *chan = data;
757 	u32 intr_cause = mv_chan_get_intr_cause(chan);
758 
759 	dev_dbg(mv_chan_to_devp(chan), "intr cause %x\n", intr_cause);
760 
761 	if (mv_is_err_intr(intr_cause))
762 		mv_xor_err_interrupt_handler(chan, intr_cause);
763 
764 	tasklet_schedule(&chan->irq_tasklet);
765 
766 	mv_xor_device_clear_eoc_cause(chan);
767 
768 	return IRQ_HANDLED;
769 }
770 
771 static void mv_xor_issue_pending(struct dma_chan *chan)
772 {
773 	struct mv_xor_chan *mv_chan = to_mv_xor_chan(chan);
774 
775 	if (mv_chan->pending >= MV_XOR_THRESHOLD) {
776 		mv_chan->pending = 0;
777 		mv_chan_activate(mv_chan);
778 	}
779 }
780 
781 /*
782  * Perform a transaction to verify the HW works.
783  */
784 
785 static int mv_xor_memcpy_self_test(struct mv_xor_chan *mv_chan)
786 {
787 	int i;
788 	void *src, *dest;
789 	dma_addr_t src_dma, dest_dma;
790 	struct dma_chan *dma_chan;
791 	dma_cookie_t cookie;
792 	struct dma_async_tx_descriptor *tx;
793 	struct dmaengine_unmap_data *unmap;
794 	int err = 0;
795 
796 	src = kmalloc(sizeof(u8) * PAGE_SIZE, GFP_KERNEL);
797 	if (!src)
798 		return -ENOMEM;
799 
800 	dest = kzalloc(sizeof(u8) * PAGE_SIZE, GFP_KERNEL);
801 	if (!dest) {
802 		kfree(src);
803 		return -ENOMEM;
804 	}
805 
806 	/* Fill in src buffer */
807 	for (i = 0; i < PAGE_SIZE; i++)
808 		((u8 *) src)[i] = (u8)i;
809 
810 	dma_chan = &mv_chan->dmachan;
811 	if (mv_xor_alloc_chan_resources(dma_chan) < 1) {
812 		err = -ENODEV;
813 		goto out;
814 	}
815 
816 	unmap = dmaengine_get_unmap_data(dma_chan->device->dev, 2, GFP_KERNEL);
817 	if (!unmap) {
818 		err = -ENOMEM;
819 		goto free_resources;
820 	}
821 
822 	src_dma = dma_map_page(dma_chan->device->dev, virt_to_page(src), 0,
823 				 PAGE_SIZE, DMA_TO_DEVICE);
824 	unmap->to_cnt = 1;
825 	unmap->addr[0] = src_dma;
826 
827 	dest_dma = dma_map_page(dma_chan->device->dev, virt_to_page(dest), 0,
828 				  PAGE_SIZE, DMA_FROM_DEVICE);
829 	unmap->from_cnt = 1;
830 	unmap->addr[1] = dest_dma;
831 
832 	unmap->len = PAGE_SIZE;
833 
834 	tx = mv_xor_prep_dma_memcpy(dma_chan, dest_dma, src_dma,
835 				    PAGE_SIZE, 0);
836 	cookie = mv_xor_tx_submit(tx);
837 	mv_xor_issue_pending(dma_chan);
838 	async_tx_ack(tx);
839 	msleep(1);
840 
841 	if (mv_xor_status(dma_chan, cookie, NULL) !=
842 	    DMA_COMPLETE) {
843 		dev_err(dma_chan->device->dev,
844 			"Self-test copy timed out, disabling\n");
845 		err = -ENODEV;
846 		goto free_resources;
847 	}
848 
849 	dma_sync_single_for_cpu(dma_chan->device->dev, dest_dma,
850 				PAGE_SIZE, DMA_FROM_DEVICE);
851 	if (memcmp(src, dest, PAGE_SIZE)) {
852 		dev_err(dma_chan->device->dev,
853 			"Self-test copy failed compare, disabling\n");
854 		err = -ENODEV;
855 		goto free_resources;
856 	}
857 
858 free_resources:
859 	dmaengine_unmap_put(unmap);
860 	mv_xor_free_chan_resources(dma_chan);
861 out:
862 	kfree(src);
863 	kfree(dest);
864 	return err;
865 }
866 
867 #define MV_XOR_NUM_SRC_TEST 4 /* must be <= 15 */
868 static int
869 mv_xor_xor_self_test(struct mv_xor_chan *mv_chan)
870 {
871 	int i, src_idx;
872 	struct page *dest;
873 	struct page *xor_srcs[MV_XOR_NUM_SRC_TEST];
874 	dma_addr_t dma_srcs[MV_XOR_NUM_SRC_TEST];
875 	dma_addr_t dest_dma;
876 	struct dma_async_tx_descriptor *tx;
877 	struct dmaengine_unmap_data *unmap;
878 	struct dma_chan *dma_chan;
879 	dma_cookie_t cookie;
880 	u8 cmp_byte = 0;
881 	u32 cmp_word;
882 	int err = 0;
883 	int src_count = MV_XOR_NUM_SRC_TEST;
884 
885 	for (src_idx = 0; src_idx < src_count; src_idx++) {
886 		xor_srcs[src_idx] = alloc_page(GFP_KERNEL);
887 		if (!xor_srcs[src_idx]) {
888 			while (src_idx--)
889 				__free_page(xor_srcs[src_idx]);
890 			return -ENOMEM;
891 		}
892 	}
893 
894 	dest = alloc_page(GFP_KERNEL);
895 	if (!dest) {
896 		while (src_idx--)
897 			__free_page(xor_srcs[src_idx]);
898 		return -ENOMEM;
899 	}
900 
901 	/* Fill in src buffers */
902 	for (src_idx = 0; src_idx < src_count; src_idx++) {
903 		u8 *ptr = page_address(xor_srcs[src_idx]);
904 		for (i = 0; i < PAGE_SIZE; i++)
905 			ptr[i] = (1 << src_idx);
906 	}
907 
908 	for (src_idx = 0; src_idx < src_count; src_idx++)
909 		cmp_byte ^= (u8) (1 << src_idx);
910 
911 	cmp_word = (cmp_byte << 24) | (cmp_byte << 16) |
912 		(cmp_byte << 8) | cmp_byte;
913 
914 	memset(page_address(dest), 0, PAGE_SIZE);
915 
916 	dma_chan = &mv_chan->dmachan;
917 	if (mv_xor_alloc_chan_resources(dma_chan) < 1) {
918 		err = -ENODEV;
919 		goto out;
920 	}
921 
922 	unmap = dmaengine_get_unmap_data(dma_chan->device->dev, src_count + 1,
923 					 GFP_KERNEL);
924 	if (!unmap) {
925 		err = -ENOMEM;
926 		goto free_resources;
927 	}
928 
929 	/* test xor */
930 	for (i = 0; i < src_count; i++) {
931 		unmap->addr[i] = dma_map_page(dma_chan->device->dev, xor_srcs[i],
932 					      0, PAGE_SIZE, DMA_TO_DEVICE);
933 		dma_srcs[i] = unmap->addr[i];
934 		unmap->to_cnt++;
935 	}
936 
937 	unmap->addr[src_count] = dma_map_page(dma_chan->device->dev, dest, 0, PAGE_SIZE,
938 				      DMA_FROM_DEVICE);
939 	dest_dma = unmap->addr[src_count];
940 	unmap->from_cnt = 1;
941 	unmap->len = PAGE_SIZE;
942 
943 	tx = mv_xor_prep_dma_xor(dma_chan, dest_dma, dma_srcs,
944 				 src_count, PAGE_SIZE, 0);
945 
946 	cookie = mv_xor_tx_submit(tx);
947 	mv_xor_issue_pending(dma_chan);
948 	async_tx_ack(tx);
949 	msleep(8);
950 
951 	if (mv_xor_status(dma_chan, cookie, NULL) !=
952 	    DMA_COMPLETE) {
953 		dev_err(dma_chan->device->dev,
954 			"Self-test xor timed out, disabling\n");
955 		err = -ENODEV;
956 		goto free_resources;
957 	}
958 
959 	dma_sync_single_for_cpu(dma_chan->device->dev, dest_dma,
960 				PAGE_SIZE, DMA_FROM_DEVICE);
961 	for (i = 0; i < (PAGE_SIZE / sizeof(u32)); i++) {
962 		u32 *ptr = page_address(dest);
963 		if (ptr[i] != cmp_word) {
964 			dev_err(dma_chan->device->dev,
965 				"Self-test xor failed compare, disabling. index %d, data %x, expected %x\n",
966 				i, ptr[i], cmp_word);
967 			err = -ENODEV;
968 			goto free_resources;
969 		}
970 	}
971 
972 free_resources:
973 	dmaengine_unmap_put(unmap);
974 	mv_xor_free_chan_resources(dma_chan);
975 out:
976 	src_idx = src_count;
977 	while (src_idx--)
978 		__free_page(xor_srcs[src_idx]);
979 	__free_page(dest);
980 	return err;
981 }
982 
983 /* This driver does not implement any of the optional DMA operations. */
984 static int
985 mv_xor_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
986 	       unsigned long arg)
987 {
988 	return -ENOSYS;
989 }
990 
991 static int mv_xor_channel_remove(struct mv_xor_chan *mv_chan)
992 {
993 	struct dma_chan *chan, *_chan;
994 	struct device *dev = mv_chan->dmadev.dev;
995 
996 	dma_async_device_unregister(&mv_chan->dmadev);
997 
998 	dma_free_coherent(dev, MV_XOR_POOL_SIZE,
999 			  mv_chan->dma_desc_pool_virt, mv_chan->dma_desc_pool);
1000 
1001 	list_for_each_entry_safe(chan, _chan, &mv_chan->dmadev.channels,
1002 				 device_node) {
1003 		list_del(&chan->device_node);
1004 	}
1005 
1006 	free_irq(mv_chan->irq, mv_chan);
1007 
1008 	return 0;
1009 }
1010 
1011 static struct mv_xor_chan *
1012 mv_xor_channel_add(struct mv_xor_device *xordev,
1013 		   struct platform_device *pdev,
1014 		   int idx, dma_cap_mask_t cap_mask, int irq)
1015 {
1016 	int ret = 0;
1017 	struct mv_xor_chan *mv_chan;
1018 	struct dma_device *dma_dev;
1019 
1020 	mv_chan = devm_kzalloc(&pdev->dev, sizeof(*mv_chan), GFP_KERNEL);
1021 	if (!mv_chan)
1022 		return ERR_PTR(-ENOMEM);
1023 
1024 	mv_chan->idx = idx;
1025 	mv_chan->irq = irq;
1026 
1027 	dma_dev = &mv_chan->dmadev;
1028 
1029 	/* allocate coherent memory for hardware descriptors
1030 	 * note: writecombine gives slightly better performance, but
1031 	 * requires that we explicitly flush the writes
1032 	 */
1033 	mv_chan->dma_desc_pool_virt =
1034 	  dma_alloc_writecombine(&pdev->dev, MV_XOR_POOL_SIZE,
1035 				 &mv_chan->dma_desc_pool, GFP_KERNEL);
1036 	if (!mv_chan->dma_desc_pool_virt)
1037 		return ERR_PTR(-ENOMEM);
1038 
1039 	/* discover transaction capabilites from the platform data */
1040 	dma_dev->cap_mask = cap_mask;
1041 
1042 	INIT_LIST_HEAD(&dma_dev->channels);
1043 
1044 	/* set base routines */
1045 	dma_dev->device_alloc_chan_resources = mv_xor_alloc_chan_resources;
1046 	dma_dev->device_free_chan_resources = mv_xor_free_chan_resources;
1047 	dma_dev->device_tx_status = mv_xor_status;
1048 	dma_dev->device_issue_pending = mv_xor_issue_pending;
1049 	dma_dev->device_control = mv_xor_control;
1050 	dma_dev->dev = &pdev->dev;
1051 
1052 	/* set prep routines based on capability */
1053 	if (dma_has_cap(DMA_MEMCPY, dma_dev->cap_mask))
1054 		dma_dev->device_prep_dma_memcpy = mv_xor_prep_dma_memcpy;
1055 	if (dma_has_cap(DMA_XOR, dma_dev->cap_mask)) {
1056 		dma_dev->max_xor = 8;
1057 		dma_dev->device_prep_dma_xor = mv_xor_prep_dma_xor;
1058 	}
1059 
1060 	mv_chan->mmr_base = xordev->xor_base;
1061 	mv_chan->mmr_high_base = xordev->xor_high_base;
1062 	tasklet_init(&mv_chan->irq_tasklet, mv_xor_tasklet, (unsigned long)
1063 		     mv_chan);
1064 
1065 	/* clear errors before enabling interrupts */
1066 	mv_xor_device_clear_err_status(mv_chan);
1067 
1068 	ret = request_irq(mv_chan->irq, mv_xor_interrupt_handler,
1069 			  0, dev_name(&pdev->dev), mv_chan);
1070 	if (ret)
1071 		goto err_free_dma;
1072 
1073 	mv_chan_unmask_interrupts(mv_chan);
1074 
1075 	mv_set_mode(mv_chan, DMA_MEMCPY);
1076 
1077 	spin_lock_init(&mv_chan->lock);
1078 	INIT_LIST_HEAD(&mv_chan->chain);
1079 	INIT_LIST_HEAD(&mv_chan->completed_slots);
1080 	INIT_LIST_HEAD(&mv_chan->all_slots);
1081 	mv_chan->dmachan.device = dma_dev;
1082 	dma_cookie_init(&mv_chan->dmachan);
1083 
1084 	list_add_tail(&mv_chan->dmachan.device_node, &dma_dev->channels);
1085 
1086 	if (dma_has_cap(DMA_MEMCPY, dma_dev->cap_mask)) {
1087 		ret = mv_xor_memcpy_self_test(mv_chan);
1088 		dev_dbg(&pdev->dev, "memcpy self test returned %d\n", ret);
1089 		if (ret)
1090 			goto err_free_irq;
1091 	}
1092 
1093 	if (dma_has_cap(DMA_XOR, dma_dev->cap_mask)) {
1094 		ret = mv_xor_xor_self_test(mv_chan);
1095 		dev_dbg(&pdev->dev, "xor self test returned %d\n", ret);
1096 		if (ret)
1097 			goto err_free_irq;
1098 	}
1099 
1100 	dev_info(&pdev->dev, "Marvell XOR: ( %s%s%s)\n",
1101 		 dma_has_cap(DMA_XOR, dma_dev->cap_mask) ? "xor " : "",
1102 		 dma_has_cap(DMA_MEMCPY, dma_dev->cap_mask) ? "cpy " : "",
1103 		 dma_has_cap(DMA_INTERRUPT, dma_dev->cap_mask) ? "intr " : "");
1104 
1105 	dma_async_device_register(dma_dev);
1106 	return mv_chan;
1107 
1108 err_free_irq:
1109 	free_irq(mv_chan->irq, mv_chan);
1110  err_free_dma:
1111 	dma_free_coherent(&pdev->dev, MV_XOR_POOL_SIZE,
1112 			  mv_chan->dma_desc_pool_virt, mv_chan->dma_desc_pool);
1113 	return ERR_PTR(ret);
1114 }
1115 
1116 static void
1117 mv_xor_conf_mbus_windows(struct mv_xor_device *xordev,
1118 			 const struct mbus_dram_target_info *dram)
1119 {
1120 	void __iomem *base = xordev->xor_high_base;
1121 	u32 win_enable = 0;
1122 	int i;
1123 
1124 	for (i = 0; i < 8; i++) {
1125 		writel(0, base + WINDOW_BASE(i));
1126 		writel(0, base + WINDOW_SIZE(i));
1127 		if (i < 4)
1128 			writel(0, base + WINDOW_REMAP_HIGH(i));
1129 	}
1130 
1131 	for (i = 0; i < dram->num_cs; i++) {
1132 		const struct mbus_dram_window *cs = dram->cs + i;
1133 
1134 		writel((cs->base & 0xffff0000) |
1135 		       (cs->mbus_attr << 8) |
1136 		       dram->mbus_dram_target_id, base + WINDOW_BASE(i));
1137 		writel((cs->size - 1) & 0xffff0000, base + WINDOW_SIZE(i));
1138 
1139 		win_enable |= (1 << i);
1140 		win_enable |= 3 << (16 + (2 * i));
1141 	}
1142 
1143 	writel(win_enable, base + WINDOW_BAR_ENABLE(0));
1144 	writel(win_enable, base + WINDOW_BAR_ENABLE(1));
1145 	writel(0, base + WINDOW_OVERRIDE_CTRL(0));
1146 	writel(0, base + WINDOW_OVERRIDE_CTRL(1));
1147 }
1148 
1149 static int mv_xor_probe(struct platform_device *pdev)
1150 {
1151 	const struct mbus_dram_target_info *dram;
1152 	struct mv_xor_device *xordev;
1153 	struct mv_xor_platform_data *pdata = dev_get_platdata(&pdev->dev);
1154 	struct resource *res;
1155 	int i, ret;
1156 
1157 	dev_notice(&pdev->dev, "Marvell shared XOR driver\n");
1158 
1159 	xordev = devm_kzalloc(&pdev->dev, sizeof(*xordev), GFP_KERNEL);
1160 	if (!xordev)
1161 		return -ENOMEM;
1162 
1163 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1164 	if (!res)
1165 		return -ENODEV;
1166 
1167 	xordev->xor_base = devm_ioremap(&pdev->dev, res->start,
1168 					resource_size(res));
1169 	if (!xordev->xor_base)
1170 		return -EBUSY;
1171 
1172 	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
1173 	if (!res)
1174 		return -ENODEV;
1175 
1176 	xordev->xor_high_base = devm_ioremap(&pdev->dev, res->start,
1177 					     resource_size(res));
1178 	if (!xordev->xor_high_base)
1179 		return -EBUSY;
1180 
1181 	platform_set_drvdata(pdev, xordev);
1182 
1183 	/*
1184 	 * (Re-)program MBUS remapping windows if we are asked to.
1185 	 */
1186 	dram = mv_mbus_dram_info();
1187 	if (dram)
1188 		mv_xor_conf_mbus_windows(xordev, dram);
1189 
1190 	/* Not all platforms can gate the clock, so it is not
1191 	 * an error if the clock does not exists.
1192 	 */
1193 	xordev->clk = clk_get(&pdev->dev, NULL);
1194 	if (!IS_ERR(xordev->clk))
1195 		clk_prepare_enable(xordev->clk);
1196 
1197 	if (pdev->dev.of_node) {
1198 		struct device_node *np;
1199 		int i = 0;
1200 
1201 		for_each_child_of_node(pdev->dev.of_node, np) {
1202 			struct mv_xor_chan *chan;
1203 			dma_cap_mask_t cap_mask;
1204 			int irq;
1205 
1206 			dma_cap_zero(cap_mask);
1207 			if (of_property_read_bool(np, "dmacap,memcpy"))
1208 				dma_cap_set(DMA_MEMCPY, cap_mask);
1209 			if (of_property_read_bool(np, "dmacap,xor"))
1210 				dma_cap_set(DMA_XOR, cap_mask);
1211 			if (of_property_read_bool(np, "dmacap,interrupt"))
1212 				dma_cap_set(DMA_INTERRUPT, cap_mask);
1213 
1214 			irq = irq_of_parse_and_map(np, 0);
1215 			if (!irq) {
1216 				ret = -ENODEV;
1217 				goto err_channel_add;
1218 			}
1219 
1220 			chan = mv_xor_channel_add(xordev, pdev, i,
1221 						  cap_mask, irq);
1222 			if (IS_ERR(chan)) {
1223 				ret = PTR_ERR(chan);
1224 				irq_dispose_mapping(irq);
1225 				goto err_channel_add;
1226 			}
1227 
1228 			xordev->channels[i] = chan;
1229 			i++;
1230 		}
1231 	} else if (pdata && pdata->channels) {
1232 		for (i = 0; i < MV_XOR_MAX_CHANNELS; i++) {
1233 			struct mv_xor_channel_data *cd;
1234 			struct mv_xor_chan *chan;
1235 			int irq;
1236 
1237 			cd = &pdata->channels[i];
1238 			if (!cd) {
1239 				ret = -ENODEV;
1240 				goto err_channel_add;
1241 			}
1242 
1243 			irq = platform_get_irq(pdev, i);
1244 			if (irq < 0) {
1245 				ret = irq;
1246 				goto err_channel_add;
1247 			}
1248 
1249 			chan = mv_xor_channel_add(xordev, pdev, i,
1250 						  cd->cap_mask, irq);
1251 			if (IS_ERR(chan)) {
1252 				ret = PTR_ERR(chan);
1253 				goto err_channel_add;
1254 			}
1255 
1256 			xordev->channels[i] = chan;
1257 		}
1258 	}
1259 
1260 	return 0;
1261 
1262 err_channel_add:
1263 	for (i = 0; i < MV_XOR_MAX_CHANNELS; i++)
1264 		if (xordev->channels[i]) {
1265 			mv_xor_channel_remove(xordev->channels[i]);
1266 			if (pdev->dev.of_node)
1267 				irq_dispose_mapping(xordev->channels[i]->irq);
1268 		}
1269 
1270 	if (!IS_ERR(xordev->clk)) {
1271 		clk_disable_unprepare(xordev->clk);
1272 		clk_put(xordev->clk);
1273 	}
1274 
1275 	return ret;
1276 }
1277 
1278 static int mv_xor_remove(struct platform_device *pdev)
1279 {
1280 	struct mv_xor_device *xordev = platform_get_drvdata(pdev);
1281 	int i;
1282 
1283 	for (i = 0; i < MV_XOR_MAX_CHANNELS; i++) {
1284 		if (xordev->channels[i])
1285 			mv_xor_channel_remove(xordev->channels[i]);
1286 	}
1287 
1288 	if (!IS_ERR(xordev->clk)) {
1289 		clk_disable_unprepare(xordev->clk);
1290 		clk_put(xordev->clk);
1291 	}
1292 
1293 	return 0;
1294 }
1295 
1296 #ifdef CONFIG_OF
1297 static struct of_device_id mv_xor_dt_ids[] = {
1298        { .compatible = "marvell,orion-xor", },
1299        {},
1300 };
1301 MODULE_DEVICE_TABLE(of, mv_xor_dt_ids);
1302 #endif
1303 
1304 static struct platform_driver mv_xor_driver = {
1305 	.probe		= mv_xor_probe,
1306 	.remove		= mv_xor_remove,
1307 	.driver		= {
1308 		.owner	        = THIS_MODULE,
1309 		.name	        = MV_XOR_NAME,
1310 		.of_match_table = of_match_ptr(mv_xor_dt_ids),
1311 	},
1312 };
1313 
1314 
1315 static int __init mv_xor_init(void)
1316 {
1317 	return platform_driver_register(&mv_xor_driver);
1318 }
1319 module_init(mv_xor_init);
1320 
1321 /* it's currently unsafe to unload this module */
1322 #if 0
1323 static void __exit mv_xor_exit(void)
1324 {
1325 	platform_driver_unregister(&mv_xor_driver);
1326 	return;
1327 }
1328 
1329 module_exit(mv_xor_exit);
1330 #endif
1331 
1332 MODULE_AUTHOR("Saeed Bishara <saeed@marvell.com>");
1333 MODULE_DESCRIPTION("DMA engine driver for Marvell's XOR engine");
1334 MODULE_LICENSE("GPL");
1335