xref: /linux/drivers/dma/loongson1-apb-dma.c (revision 3a39d672e7f48b8d6b91a09afa4b55352773b4b5)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Driver for Loongson-1 APB DMA Controller
4  *
5  * Copyright (C) 2015-2024 Keguang Zhang <keguang.zhang@gmail.com>
6  */
7 
8 #include <linux/dmapool.h>
9 #include <linux/dma-mapping.h>
10 #include <linux/init.h>
11 #include <linux/interrupt.h>
12 #include <linux/iopoll.h>
13 #include <linux/module.h>
14 #include <linux/of.h>
15 #include <linux/of_dma.h>
16 #include <linux/platform_device.h>
17 #include <linux/slab.h>
18 
19 #include "dmaengine.h"
20 #include "virt-dma.h"
21 
22 /* Loongson-1 DMA Control Register */
23 #define LS1X_DMA_CTRL		0x0
24 
25 /* DMA Control Register Bits */
26 #define LS1X_DMA_STOP		BIT(4)
27 #define LS1X_DMA_START		BIT(3)
28 #define LS1X_DMA_ASK_VALID	BIT(2)
29 
30 /* DMA Next Field Bits */
31 #define LS1X_DMA_NEXT_VALID	BIT(0)
32 
33 /* DMA Command Field Bits */
34 #define LS1X_DMA_RAM2DEV	BIT(12)
35 #define LS1X_DMA_INT		BIT(1)
36 #define LS1X_DMA_INT_MASK	BIT(0)
37 
38 #define LS1X_DMA_LLI_ALIGNMENT	64
39 #define LS1X_DMA_LLI_ADDR_MASK	GENMASK(31, __ffs(LS1X_DMA_LLI_ALIGNMENT))
40 #define LS1X_DMA_MAX_CHANNELS	3
41 
42 enum ls1x_dmadesc_offsets {
43 	LS1X_DMADESC_NEXT = 0,
44 	LS1X_DMADESC_SADDR,
45 	LS1X_DMADESC_DADDR,
46 	LS1X_DMADESC_LENGTH,
47 	LS1X_DMADESC_STRIDE,
48 	LS1X_DMADESC_CYCLES,
49 	LS1X_DMADESC_CMD,
50 	LS1X_DMADESC_SIZE
51 };
52 
53 struct ls1x_dma_lli {
54 	unsigned int hw[LS1X_DMADESC_SIZE];
55 	dma_addr_t phys;
56 	struct list_head node;
57 } __aligned(LS1X_DMA_LLI_ALIGNMENT);
58 
59 struct ls1x_dma_desc {
60 	struct virt_dma_desc vd;
61 	struct list_head lli_list;
62 };
63 
64 struct ls1x_dma_chan {
65 	struct virt_dma_chan vc;
66 	struct dma_pool *lli_pool;
67 	phys_addr_t src_addr;
68 	phys_addr_t dst_addr;
69 	enum dma_slave_buswidth src_addr_width;
70 	enum dma_slave_buswidth dst_addr_width;
71 	unsigned int bus_width;
72 	void __iomem *reg_base;
73 	int irq;
74 	bool is_cyclic;
75 	struct ls1x_dma_lli *curr_lli;
76 };
77 
78 struct ls1x_dma {
79 	struct dma_device ddev;
80 	unsigned int nr_chans;
81 	struct ls1x_dma_chan chan[];
82 };
83 
84 static irqreturn_t ls1x_dma_irq_handler(int irq, void *data);
85 
86 #define to_ls1x_dma_chan(dchan)		\
87 	container_of(dchan, struct ls1x_dma_chan, vc.chan)
88 
89 #define to_ls1x_dma_desc(d)		\
90 	container_of(d, struct ls1x_dma_desc, vd)
91 
chan2dev(struct dma_chan * chan)92 static inline struct device *chan2dev(struct dma_chan *chan)
93 {
94 	return &chan->dev->device;
95 }
96 
ls1x_dma_query(struct ls1x_dma_chan * chan,dma_addr_t * lli_phys)97 static inline int ls1x_dma_query(struct ls1x_dma_chan *chan,
98 				 dma_addr_t *lli_phys)
99 {
100 	struct dma_chan *dchan = &chan->vc.chan;
101 	int val, ret;
102 
103 	val = *lli_phys & LS1X_DMA_LLI_ADDR_MASK;
104 	val |= LS1X_DMA_ASK_VALID;
105 	val |= dchan->chan_id;
106 	writel(val, chan->reg_base + LS1X_DMA_CTRL);
107 	ret = readl_poll_timeout_atomic(chan->reg_base + LS1X_DMA_CTRL, val,
108 					!(val & LS1X_DMA_ASK_VALID), 0, 3000);
109 	if (ret)
110 		dev_err(chan2dev(dchan), "failed to query DMA\n");
111 
112 	return ret;
113 }
114 
ls1x_dma_start(struct ls1x_dma_chan * chan,dma_addr_t * lli_phys)115 static inline int ls1x_dma_start(struct ls1x_dma_chan *chan,
116 				 dma_addr_t *lli_phys)
117 {
118 	struct dma_chan *dchan = &chan->vc.chan;
119 	struct device *dev = chan2dev(dchan);
120 	int val, ret;
121 
122 	val = *lli_phys & LS1X_DMA_LLI_ADDR_MASK;
123 	val |= LS1X_DMA_START;
124 	val |= dchan->chan_id;
125 	writel(val, chan->reg_base + LS1X_DMA_CTRL);
126 	ret = readl_poll_timeout(chan->reg_base + LS1X_DMA_CTRL, val,
127 				 !(val & LS1X_DMA_START), 0, 1000);
128 	if (!ret)
129 		dev_dbg(dev, "start DMA with lli_phys=%pad\n", lli_phys);
130 	else
131 		dev_err(dev, "failed to start DMA\n");
132 
133 	return ret;
134 }
135 
ls1x_dma_stop(struct ls1x_dma_chan * chan)136 static inline void ls1x_dma_stop(struct ls1x_dma_chan *chan)
137 {
138 	int val = readl(chan->reg_base + LS1X_DMA_CTRL);
139 
140 	writel(val | LS1X_DMA_STOP, chan->reg_base + LS1X_DMA_CTRL);
141 }
142 
ls1x_dma_free_chan_resources(struct dma_chan * dchan)143 static void ls1x_dma_free_chan_resources(struct dma_chan *dchan)
144 {
145 	struct ls1x_dma_chan *chan = to_ls1x_dma_chan(dchan);
146 	struct device *dev = chan2dev(dchan);
147 
148 	dma_free_coherent(dev, sizeof(struct ls1x_dma_lli),
149 			  chan->curr_lli, chan->curr_lli->phys);
150 	dma_pool_destroy(chan->lli_pool);
151 	chan->lli_pool = NULL;
152 	devm_free_irq(dev, chan->irq, chan);
153 	vchan_free_chan_resources(&chan->vc);
154 }
155 
ls1x_dma_alloc_chan_resources(struct dma_chan * dchan)156 static int ls1x_dma_alloc_chan_resources(struct dma_chan *dchan)
157 {
158 	struct ls1x_dma_chan *chan = to_ls1x_dma_chan(dchan);
159 	struct device *dev = chan2dev(dchan);
160 	dma_addr_t phys;
161 	int ret;
162 
163 	ret = devm_request_irq(dev, chan->irq, ls1x_dma_irq_handler,
164 			       IRQF_SHARED, dma_chan_name(dchan), chan);
165 	if (ret) {
166 		dev_err(dev, "failed to request IRQ %d\n", chan->irq);
167 		return ret;
168 	}
169 
170 	chan->lli_pool = dma_pool_create(dma_chan_name(dchan), dev,
171 					 sizeof(struct ls1x_dma_lli),
172 					 __alignof__(struct ls1x_dma_lli), 0);
173 	if (!chan->lli_pool)
174 		return -ENOMEM;
175 
176 	/* allocate memory for querying the current lli */
177 	dma_set_coherent_mask(dev, DMA_BIT_MASK(32));
178 	chan->curr_lli = dma_alloc_coherent(dev, sizeof(struct ls1x_dma_lli),
179 					    &phys, GFP_KERNEL);
180 	if (!chan->curr_lli) {
181 		dma_pool_destroy(chan->lli_pool);
182 		return -ENOMEM;
183 	}
184 	chan->curr_lli->phys = phys;
185 
186 	return 0;
187 }
188 
ls1x_dma_free_desc(struct virt_dma_desc * vd)189 static void ls1x_dma_free_desc(struct virt_dma_desc *vd)
190 {
191 	struct ls1x_dma_desc *desc = to_ls1x_dma_desc(vd);
192 	struct ls1x_dma_chan *chan = to_ls1x_dma_chan(vd->tx.chan);
193 	struct ls1x_dma_lli *lli, *_lli;
194 
195 	list_for_each_entry_safe(lli, _lli, &desc->lli_list, node) {
196 		list_del(&lli->node);
197 		dma_pool_free(chan->lli_pool, lli, lli->phys);
198 	}
199 
200 	kfree(desc);
201 }
202 
ls1x_dma_alloc_desc(void)203 static struct ls1x_dma_desc *ls1x_dma_alloc_desc(void)
204 {
205 	struct ls1x_dma_desc *desc;
206 
207 	desc = kzalloc(sizeof(*desc), GFP_NOWAIT);
208 	if (!desc)
209 		return NULL;
210 
211 	INIT_LIST_HEAD(&desc->lli_list);
212 
213 	return desc;
214 }
215 
ls1x_dma_prep_lli(struct dma_chan * dchan,struct ls1x_dma_desc * desc,struct scatterlist * sgl,unsigned int sg_len,enum dma_transfer_direction dir,bool is_cyclic)216 static int ls1x_dma_prep_lli(struct dma_chan *dchan, struct ls1x_dma_desc *desc,
217 			     struct scatterlist *sgl, unsigned int sg_len,
218 			     enum dma_transfer_direction dir, bool is_cyclic)
219 {
220 	struct ls1x_dma_chan *chan = to_ls1x_dma_chan(dchan);
221 	struct ls1x_dma_lli *lli, *prev = NULL, *first = NULL;
222 	struct device *dev = chan2dev(dchan);
223 	struct list_head *pos = NULL;
224 	struct scatterlist *sg;
225 	unsigned int dev_addr, cmd, i;
226 
227 	switch (dir) {
228 	case DMA_MEM_TO_DEV:
229 		dev_addr = chan->dst_addr;
230 		chan->bus_width = chan->dst_addr_width;
231 		cmd = LS1X_DMA_RAM2DEV | LS1X_DMA_INT;
232 		break;
233 	case DMA_DEV_TO_MEM:
234 		dev_addr = chan->src_addr;
235 		chan->bus_width = chan->src_addr_width;
236 		cmd = LS1X_DMA_INT;
237 		break;
238 	default:
239 		dev_err(dev, "unsupported DMA direction: %s\n",
240 			dmaengine_get_direction_text(dir));
241 		return -EINVAL;
242 	}
243 
244 	for_each_sg(sgl, sg, sg_len, i) {
245 		dma_addr_t buf_addr = sg_dma_address(sg);
246 		size_t buf_len = sg_dma_len(sg);
247 		dma_addr_t phys;
248 
249 		if (!is_dma_copy_aligned(dchan->device, buf_addr, 0, buf_len)) {
250 			dev_err(dev, "buffer is not aligned\n");
251 			return -EINVAL;
252 		}
253 
254 		/* allocate HW descriptors */
255 		lli = dma_pool_zalloc(chan->lli_pool, GFP_NOWAIT, &phys);
256 		if (!lli) {
257 			dev_err(dev, "failed to alloc lli %u\n", i);
258 			return -ENOMEM;
259 		}
260 
261 		/* setup HW descriptors */
262 		lli->phys = phys;
263 		lli->hw[LS1X_DMADESC_SADDR] = buf_addr;
264 		lli->hw[LS1X_DMADESC_DADDR] = dev_addr;
265 		lli->hw[LS1X_DMADESC_LENGTH] = buf_len / chan->bus_width;
266 		lli->hw[LS1X_DMADESC_STRIDE] = 0;
267 		lli->hw[LS1X_DMADESC_CYCLES] = 1;
268 		lli->hw[LS1X_DMADESC_CMD] = cmd;
269 
270 		if (prev)
271 			prev->hw[LS1X_DMADESC_NEXT] =
272 			    lli->phys | LS1X_DMA_NEXT_VALID;
273 		prev = lli;
274 
275 		if (!first)
276 			first = lli;
277 
278 		list_add_tail(&lli->node, &desc->lli_list);
279 	}
280 
281 	if (is_cyclic) {
282 		lli->hw[LS1X_DMADESC_NEXT] = first->phys | LS1X_DMA_NEXT_VALID;
283 		chan->is_cyclic = is_cyclic;
284 	}
285 
286 	list_for_each(pos, &desc->lli_list) {
287 		lli = list_entry(pos, struct ls1x_dma_lli, node);
288 		print_hex_dump_debug("LLI: ", DUMP_PREFIX_OFFSET, 16, 4,
289 				     lli, sizeof(*lli), false);
290 	}
291 
292 	return 0;
293 }
294 
295 static struct dma_async_tx_descriptor *
ls1x_dma_prep_slave_sg(struct dma_chan * dchan,struct scatterlist * sgl,unsigned int sg_len,enum dma_transfer_direction dir,unsigned long flags,void * context)296 ls1x_dma_prep_slave_sg(struct dma_chan *dchan, struct scatterlist *sgl,
297 		       unsigned int sg_len, enum dma_transfer_direction dir,
298 		       unsigned long flags, void *context)
299 {
300 	struct ls1x_dma_desc *desc;
301 
302 	dev_dbg(chan2dev(dchan), "sg_len=%u flags=0x%lx dir=%s\n",
303 		sg_len, flags, dmaengine_get_direction_text(dir));
304 
305 	desc = ls1x_dma_alloc_desc();
306 	if (!desc)
307 		return NULL;
308 
309 	if (ls1x_dma_prep_lli(dchan, desc, sgl, sg_len, dir, false)) {
310 		ls1x_dma_free_desc(&desc->vd);
311 		return NULL;
312 	}
313 
314 	return vchan_tx_prep(to_virt_chan(dchan), &desc->vd, flags);
315 }
316 
317 static struct dma_async_tx_descriptor *
ls1x_dma_prep_dma_cyclic(struct dma_chan * dchan,dma_addr_t buf_addr,size_t buf_len,size_t period_len,enum dma_transfer_direction dir,unsigned long flags)318 ls1x_dma_prep_dma_cyclic(struct dma_chan *dchan, dma_addr_t buf_addr,
319 			 size_t buf_len, size_t period_len,
320 			 enum dma_transfer_direction dir, unsigned long flags)
321 {
322 	struct ls1x_dma_desc *desc;
323 	struct scatterlist *sgl;
324 	unsigned int sg_len;
325 	unsigned int i;
326 	int ret;
327 
328 	dev_dbg(chan2dev(dchan),
329 		"buf_len=%zu period_len=%zu flags=0x%lx dir=%s\n",
330 		buf_len, period_len, flags, dmaengine_get_direction_text(dir));
331 
332 	desc = ls1x_dma_alloc_desc();
333 	if (!desc)
334 		return NULL;
335 
336 	/* allocate the scatterlist */
337 	sg_len = buf_len / period_len;
338 	sgl = kmalloc_array(sg_len, sizeof(*sgl), GFP_NOWAIT);
339 	if (!sgl)
340 		return NULL;
341 
342 	sg_init_table(sgl, sg_len);
343 	for (i = 0; i < sg_len; ++i) {
344 		sg_set_page(&sgl[i], pfn_to_page(PFN_DOWN(buf_addr)),
345 			    period_len, offset_in_page(buf_addr));
346 		sg_dma_address(&sgl[i]) = buf_addr;
347 		sg_dma_len(&sgl[i]) = period_len;
348 		buf_addr += period_len;
349 	}
350 
351 	ret = ls1x_dma_prep_lli(dchan, desc, sgl, sg_len, dir, true);
352 	kfree(sgl);
353 	if (ret) {
354 		ls1x_dma_free_desc(&desc->vd);
355 		return NULL;
356 	}
357 
358 	return vchan_tx_prep(to_virt_chan(dchan), &desc->vd, flags);
359 }
360 
ls1x_dma_slave_config(struct dma_chan * dchan,struct dma_slave_config * config)361 static int ls1x_dma_slave_config(struct dma_chan *dchan,
362 				 struct dma_slave_config *config)
363 {
364 	struct ls1x_dma_chan *chan = to_ls1x_dma_chan(dchan);
365 
366 	chan->src_addr = config->src_addr;
367 	chan->src_addr_width = config->src_addr_width;
368 	chan->dst_addr = config->dst_addr;
369 	chan->dst_addr_width = config->dst_addr_width;
370 
371 	return 0;
372 }
373 
ls1x_dma_pause(struct dma_chan * dchan)374 static int ls1x_dma_pause(struct dma_chan *dchan)
375 {
376 	struct ls1x_dma_chan *chan = to_ls1x_dma_chan(dchan);
377 	int ret;
378 
379 	guard(spinlock_irqsave)(&chan->vc.lock);
380 	/* save the current lli */
381 	ret = ls1x_dma_query(chan, &chan->curr_lli->phys);
382 	if (!ret)
383 		ls1x_dma_stop(chan);
384 
385 	return ret;
386 }
387 
ls1x_dma_resume(struct dma_chan * dchan)388 static int ls1x_dma_resume(struct dma_chan *dchan)
389 {
390 	struct ls1x_dma_chan *chan = to_ls1x_dma_chan(dchan);
391 
392 	guard(spinlock_irqsave)(&chan->vc.lock);
393 
394 	return ls1x_dma_start(chan, &chan->curr_lli->phys);
395 }
396 
ls1x_dma_terminate_all(struct dma_chan * dchan)397 static int ls1x_dma_terminate_all(struct dma_chan *dchan)
398 {
399 	struct ls1x_dma_chan *chan = to_ls1x_dma_chan(dchan);
400 	struct virt_dma_desc *vd;
401 	LIST_HEAD(head);
402 
403 	ls1x_dma_stop(chan);
404 
405 	scoped_guard(spinlock_irqsave, &chan->vc.lock) {
406 		vd = vchan_next_desc(&chan->vc);
407 		if (vd)
408 			vchan_terminate_vdesc(vd);
409 
410 		vchan_get_all_descriptors(&chan->vc, &head);
411 	}
412 
413 	vchan_dma_desc_free_list(&chan->vc, &head);
414 
415 	return 0;
416 }
417 
ls1x_dma_synchronize(struct dma_chan * dchan)418 static void ls1x_dma_synchronize(struct dma_chan *dchan)
419 {
420 	vchan_synchronize(to_virt_chan(dchan));
421 }
422 
ls1x_dma_tx_status(struct dma_chan * dchan,dma_cookie_t cookie,struct dma_tx_state * state)423 static enum dma_status ls1x_dma_tx_status(struct dma_chan *dchan,
424 					  dma_cookie_t cookie,
425 					  struct dma_tx_state *state)
426 {
427 	struct ls1x_dma_chan *chan = to_ls1x_dma_chan(dchan);
428 	struct virt_dma_desc *vd;
429 	enum dma_status status;
430 	size_t bytes = 0;
431 
432 	status = dma_cookie_status(dchan, cookie, state);
433 	if (status == DMA_COMPLETE)
434 		return status;
435 
436 	scoped_guard(spinlock_irqsave, &chan->vc.lock) {
437 		vd = vchan_find_desc(&chan->vc, cookie);
438 		if (vd) {
439 			struct ls1x_dma_desc *desc = to_ls1x_dma_desc(vd);
440 			struct ls1x_dma_lli *lli;
441 			dma_addr_t next_phys;
442 
443 			/* get the current lli */
444 			if (ls1x_dma_query(chan, &chan->curr_lli->phys))
445 				return status;
446 
447 			/* locate the current lli */
448 			next_phys = chan->curr_lli->hw[LS1X_DMADESC_NEXT];
449 			list_for_each_entry(lli, &desc->lli_list, node)
450 				if (lli->hw[LS1X_DMADESC_NEXT] == next_phys)
451 					break;
452 
453 			dev_dbg(chan2dev(dchan), "current lli_phys=%pad",
454 				&lli->phys);
455 
456 			/* count the residues */
457 			list_for_each_entry_from(lli, &desc->lli_list, node)
458 				bytes += lli->hw[LS1X_DMADESC_LENGTH] *
459 					 chan->bus_width;
460 		}
461 	}
462 
463 	dma_set_residue(state, bytes);
464 
465 	return status;
466 }
467 
ls1x_dma_issue_pending(struct dma_chan * dchan)468 static void ls1x_dma_issue_pending(struct dma_chan *dchan)
469 {
470 	struct ls1x_dma_chan *chan = to_ls1x_dma_chan(dchan);
471 
472 	guard(spinlock_irqsave)(&chan->vc.lock);
473 
474 	if (vchan_issue_pending(&chan->vc)) {
475 		struct virt_dma_desc *vd = vchan_next_desc(&chan->vc);
476 
477 		if (vd) {
478 			struct ls1x_dma_desc *desc = to_ls1x_dma_desc(vd);
479 			struct ls1x_dma_lli *lli;
480 
481 			lli = list_first_entry(&desc->lli_list,
482 					       struct ls1x_dma_lli, node);
483 			ls1x_dma_start(chan, &lli->phys);
484 		}
485 	}
486 }
487 
ls1x_dma_irq_handler(int irq,void * data)488 static irqreturn_t ls1x_dma_irq_handler(int irq, void *data)
489 {
490 	struct ls1x_dma_chan *chan = data;
491 	struct dma_chan *dchan = &chan->vc.chan;
492 	struct device *dev = chan2dev(dchan);
493 	struct virt_dma_desc *vd;
494 
495 	scoped_guard(spinlock, &chan->vc.lock) {
496 		vd = vchan_next_desc(&chan->vc);
497 		if (!vd) {
498 			dev_warn(dev,
499 				 "IRQ %d with no active desc on channel %d\n",
500 				 irq, dchan->chan_id);
501 			return IRQ_NONE;
502 		}
503 
504 		if (chan->is_cyclic) {
505 			vchan_cyclic_callback(vd);
506 		} else {
507 			list_del(&vd->node);
508 			vchan_cookie_complete(vd);
509 		}
510 	}
511 
512 	dev_dbg(dev, "DMA IRQ %d on channel %d\n", irq, dchan->chan_id);
513 
514 	return IRQ_HANDLED;
515 }
516 
ls1x_dma_chan_probe(struct platform_device * pdev,struct ls1x_dma * dma)517 static int ls1x_dma_chan_probe(struct platform_device *pdev,
518 			       struct ls1x_dma *dma)
519 {
520 	void __iomem *reg_base;
521 	int id;
522 
523 	reg_base = devm_platform_ioremap_resource(pdev, 0);
524 	if (IS_ERR(reg_base))
525 		return PTR_ERR(reg_base);
526 
527 	for (id = 0; id < dma->nr_chans; id++) {
528 		struct ls1x_dma_chan *chan = &dma->chan[id];
529 		char pdev_irqname[16];
530 
531 		snprintf(pdev_irqname, sizeof(pdev_irqname), "ch%d", id);
532 		chan->irq = platform_get_irq_byname(pdev, pdev_irqname);
533 		if (chan->irq < 0)
534 			return dev_err_probe(&pdev->dev, chan->irq,
535 					     "failed to get IRQ for ch%d\n",
536 					     id);
537 
538 		chan->reg_base = reg_base;
539 		chan->vc.desc_free = ls1x_dma_free_desc;
540 		vchan_init(&chan->vc, &dma->ddev);
541 	}
542 
543 	return 0;
544 }
545 
ls1x_dma_chan_remove(struct ls1x_dma * dma)546 static void ls1x_dma_chan_remove(struct ls1x_dma *dma)
547 {
548 	int id;
549 
550 	for (id = 0; id < dma->nr_chans; id++) {
551 		struct ls1x_dma_chan *chan = &dma->chan[id];
552 
553 		if (chan->vc.chan.device == &dma->ddev) {
554 			list_del(&chan->vc.chan.device_node);
555 			tasklet_kill(&chan->vc.task);
556 		}
557 	}
558 }
559 
ls1x_dma_probe(struct platform_device * pdev)560 static int ls1x_dma_probe(struct platform_device *pdev)
561 {
562 	struct device *dev = &pdev->dev;
563 	struct dma_device *ddev;
564 	struct ls1x_dma *dma;
565 	int ret;
566 
567 	ret = platform_irq_count(pdev);
568 	if (ret <= 0 || ret > LS1X_DMA_MAX_CHANNELS)
569 		return dev_err_probe(dev, -EINVAL,
570 				     "Invalid number of IRQ channels: %d\n",
571 				     ret);
572 
573 	dma = devm_kzalloc(dev, struct_size(dma, chan, ret), GFP_KERNEL);
574 	if (!dma)
575 		return -ENOMEM;
576 	dma->nr_chans = ret;
577 
578 	/* initialize DMA device */
579 	ddev = &dma->ddev;
580 	ddev->dev = dev;
581 	ddev->copy_align = DMAENGINE_ALIGN_4_BYTES;
582 	ddev->src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
583 				BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
584 				BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
585 	ddev->dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
586 				BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
587 				BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
588 	ddev->directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
589 	ddev->residue_granularity = DMA_RESIDUE_GRANULARITY_SEGMENT;
590 	ddev->device_alloc_chan_resources = ls1x_dma_alloc_chan_resources;
591 	ddev->device_free_chan_resources = ls1x_dma_free_chan_resources;
592 	ddev->device_prep_slave_sg = ls1x_dma_prep_slave_sg;
593 	ddev->device_prep_dma_cyclic = ls1x_dma_prep_dma_cyclic;
594 	ddev->device_config = ls1x_dma_slave_config;
595 	ddev->device_pause = ls1x_dma_pause;
596 	ddev->device_resume = ls1x_dma_resume;
597 	ddev->device_terminate_all = ls1x_dma_terminate_all;
598 	ddev->device_synchronize = ls1x_dma_synchronize;
599 	ddev->device_tx_status = ls1x_dma_tx_status;
600 	ddev->device_issue_pending = ls1x_dma_issue_pending;
601 	dma_cap_set(DMA_SLAVE, ddev->cap_mask);
602 	INIT_LIST_HEAD(&ddev->channels);
603 
604 	/* initialize DMA channels */
605 	ret = ls1x_dma_chan_probe(pdev, dma);
606 	if (ret)
607 		goto err;
608 
609 	ret = dmaenginem_async_device_register(ddev);
610 	if (ret) {
611 		dev_err(dev, "failed to register DMA device\n");
612 		goto err;
613 	}
614 
615 	ret = of_dma_controller_register(dev->of_node, of_dma_xlate_by_chan_id,
616 					 ddev);
617 	if (ret) {
618 		dev_err(dev, "failed to register DMA controller\n");
619 		goto err;
620 	}
621 
622 	platform_set_drvdata(pdev, dma);
623 	dev_info(dev, "Loongson1 DMA driver registered\n");
624 
625 	return 0;
626 
627 err:
628 	ls1x_dma_chan_remove(dma);
629 
630 	return ret;
631 }
632 
ls1x_dma_remove(struct platform_device * pdev)633 static void ls1x_dma_remove(struct platform_device *pdev)
634 {
635 	struct ls1x_dma *dma = platform_get_drvdata(pdev);
636 
637 	of_dma_controller_free(pdev->dev.of_node);
638 	ls1x_dma_chan_remove(dma);
639 }
640 
641 static const struct of_device_id ls1x_dma_match[] = {
642 	{ .compatible = "loongson,ls1b-apbdma" },
643 	{ /* sentinel */ }
644 };
645 MODULE_DEVICE_TABLE(of, ls1x_dma_match);
646 
647 static struct platform_driver ls1x_dma_driver = {
648 	.probe = ls1x_dma_probe,
649 	.remove = ls1x_dma_remove,
650 	.driver = {
651 		.name = KBUILD_MODNAME,
652 		.of_match_table = ls1x_dma_match,
653 	},
654 };
655 
656 module_platform_driver(ls1x_dma_driver);
657 
658 MODULE_AUTHOR("Keguang Zhang <keguang.zhang@gmail.com>");
659 MODULE_DESCRIPTION("Loongson-1 APB DMA Controller driver");
660 MODULE_LICENSE("GPL");
661