1 /*
2  * DMA controller driver for CSR SiRFprimaII
3  *
4  * Copyright (c) 2011 Cambridge Silicon Radio Limited, a CSR plc group company.
5  *
6  * Licensed under GPLv2 or later.
7  */
8 
9 #include <linux/module.h>
10 #include <linux/dmaengine.h>
11 #include <linux/dma-mapping.h>
12 #include <linux/interrupt.h>
13 #include <linux/io.h>
14 #include <linux/slab.h>
15 #include <linux/of_irq.h>
16 #include <linux/of_address.h>
17 #include <linux/of_device.h>
18 #include <linux/of_platform.h>
19 #include <linux/sirfsoc_dma.h>
20 
21 #include "dmaengine.h"
22 
23 #define SIRFSOC_DMA_DESCRIPTORS                 16
24 #define SIRFSOC_DMA_CHANNELS                    16
25 
26 #define SIRFSOC_DMA_CH_ADDR                     0x00
27 #define SIRFSOC_DMA_CH_XLEN                     0x04
28 #define SIRFSOC_DMA_CH_YLEN                     0x08
29 #define SIRFSOC_DMA_CH_CTRL                     0x0C
30 
31 #define SIRFSOC_DMA_WIDTH_0                     0x100
32 #define SIRFSOC_DMA_CH_VALID                    0x140
33 #define SIRFSOC_DMA_CH_INT                      0x144
34 #define SIRFSOC_DMA_INT_EN                      0x148
35 #define SIRFSOC_DMA_CH_LOOP_CTRL                0x150
36 
37 #define SIRFSOC_DMA_MODE_CTRL_BIT               4
38 #define SIRFSOC_DMA_DIR_CTRL_BIT                5
39 
40 /* xlen and dma_width register is in 4 bytes boundary */
41 #define SIRFSOC_DMA_WORD_LEN			4
42 
43 struct sirfsoc_dma_desc {
44 	struct dma_async_tx_descriptor	desc;
45 	struct list_head		node;
46 
47 	/* SiRFprimaII 2D-DMA parameters */
48 
49 	int             xlen;           /* DMA xlen */
50 	int             ylen;           /* DMA ylen */
51 	int             width;          /* DMA width */
52 	int             dir;
53 	bool            cyclic;         /* is loop DMA? */
54 	u32             addr;		/* DMA buffer address */
55 };
56 
57 struct sirfsoc_dma_chan {
58 	struct dma_chan			chan;
59 	struct list_head		free;
60 	struct list_head		prepared;
61 	struct list_head		queued;
62 	struct list_head		active;
63 	struct list_head		completed;
64 	unsigned long			happened_cyclic;
65 	unsigned long			completed_cyclic;
66 
67 	/* Lock for this structure */
68 	spinlock_t			lock;
69 
70 	int				mode;
71 };
72 
73 struct sirfsoc_dma {
74 	struct dma_device		dma;
75 	struct tasklet_struct		tasklet;
76 	struct sirfsoc_dma_chan		channels[SIRFSOC_DMA_CHANNELS];
77 	void __iomem			*base;
78 	int				irq;
79 };
80 
81 #define DRV_NAME	"sirfsoc_dma"
82 
83 /* Convert struct dma_chan to struct sirfsoc_dma_chan */
84 static inline
dma_chan_to_sirfsoc_dma_chan(struct dma_chan * c)85 struct sirfsoc_dma_chan *dma_chan_to_sirfsoc_dma_chan(struct dma_chan *c)
86 {
87 	return container_of(c, struct sirfsoc_dma_chan, chan);
88 }
89 
90 /* Convert struct dma_chan to struct sirfsoc_dma */
dma_chan_to_sirfsoc_dma(struct dma_chan * c)91 static inline struct sirfsoc_dma *dma_chan_to_sirfsoc_dma(struct dma_chan *c)
92 {
93 	struct sirfsoc_dma_chan *schan = dma_chan_to_sirfsoc_dma_chan(c);
94 	return container_of(schan, struct sirfsoc_dma, channels[c->chan_id]);
95 }
96 
97 /* Execute all queued DMA descriptors */
sirfsoc_dma_execute(struct sirfsoc_dma_chan * schan)98 static void sirfsoc_dma_execute(struct sirfsoc_dma_chan *schan)
99 {
100 	struct sirfsoc_dma *sdma = dma_chan_to_sirfsoc_dma(&schan->chan);
101 	int cid = schan->chan.chan_id;
102 	struct sirfsoc_dma_desc *sdesc = NULL;
103 
104 	/*
105 	 * lock has been held by functions calling this, so we don't hold
106 	 * lock again
107 	 */
108 
109 	sdesc = list_first_entry(&schan->queued, struct sirfsoc_dma_desc,
110 		node);
111 	/* Move the first queued descriptor to active list */
112 	list_move_tail(&sdesc->node, &schan->active);
113 
114 	/* Start the DMA transfer */
115 	writel_relaxed(sdesc->width, sdma->base + SIRFSOC_DMA_WIDTH_0 +
116 		cid * 4);
117 	writel_relaxed(cid | (schan->mode << SIRFSOC_DMA_MODE_CTRL_BIT) |
118 		(sdesc->dir << SIRFSOC_DMA_DIR_CTRL_BIT),
119 		sdma->base + cid * 0x10 + SIRFSOC_DMA_CH_CTRL);
120 	writel_relaxed(sdesc->xlen, sdma->base + cid * 0x10 +
121 		SIRFSOC_DMA_CH_XLEN);
122 	writel_relaxed(sdesc->ylen, sdma->base + cid * 0x10 +
123 		SIRFSOC_DMA_CH_YLEN);
124 	writel_relaxed(readl_relaxed(sdma->base + SIRFSOC_DMA_INT_EN) |
125 		(1 << cid), sdma->base + SIRFSOC_DMA_INT_EN);
126 
127 	/*
128 	 * writel has an implict memory write barrier to make sure data is
129 	 * flushed into memory before starting DMA
130 	 */
131 	writel(sdesc->addr >> 2, sdma->base + cid * 0x10 + SIRFSOC_DMA_CH_ADDR);
132 
133 	if (sdesc->cyclic) {
134 		writel((1 << cid) | 1 << (cid + 16) |
135 			readl_relaxed(sdma->base + SIRFSOC_DMA_CH_LOOP_CTRL),
136 			sdma->base + SIRFSOC_DMA_CH_LOOP_CTRL);
137 		schan->happened_cyclic = schan->completed_cyclic = 0;
138 	}
139 }
140 
141 /* Interrupt handler */
sirfsoc_dma_irq(int irq,void * data)142 static irqreturn_t sirfsoc_dma_irq(int irq, void *data)
143 {
144 	struct sirfsoc_dma *sdma = data;
145 	struct sirfsoc_dma_chan *schan;
146 	struct sirfsoc_dma_desc *sdesc = NULL;
147 	u32 is;
148 	int ch;
149 
150 	is = readl(sdma->base + SIRFSOC_DMA_CH_INT);
151 	while ((ch = fls(is) - 1) >= 0) {
152 		is &= ~(1 << ch);
153 		writel_relaxed(1 << ch, sdma->base + SIRFSOC_DMA_CH_INT);
154 		schan = &sdma->channels[ch];
155 
156 		spin_lock(&schan->lock);
157 
158 		sdesc = list_first_entry(&schan->active, struct sirfsoc_dma_desc,
159 			node);
160 		if (!sdesc->cyclic) {
161 			/* Execute queued descriptors */
162 			list_splice_tail_init(&schan->active, &schan->completed);
163 			if (!list_empty(&schan->queued))
164 				sirfsoc_dma_execute(schan);
165 		} else
166 			schan->happened_cyclic++;
167 
168 		spin_unlock(&schan->lock);
169 	}
170 
171 	/* Schedule tasklet */
172 	tasklet_schedule(&sdma->tasklet);
173 
174 	return IRQ_HANDLED;
175 }
176 
177 /* process completed descriptors */
sirfsoc_dma_process_completed(struct sirfsoc_dma * sdma)178 static void sirfsoc_dma_process_completed(struct sirfsoc_dma *sdma)
179 {
180 	dma_cookie_t last_cookie = 0;
181 	struct sirfsoc_dma_chan *schan;
182 	struct sirfsoc_dma_desc *sdesc;
183 	struct dma_async_tx_descriptor *desc;
184 	unsigned long flags;
185 	unsigned long happened_cyclic;
186 	LIST_HEAD(list);
187 	int i;
188 
189 	for (i = 0; i < sdma->dma.chancnt; i++) {
190 		schan = &sdma->channels[i];
191 
192 		/* Get all completed descriptors */
193 		spin_lock_irqsave(&schan->lock, flags);
194 		if (!list_empty(&schan->completed)) {
195 			list_splice_tail_init(&schan->completed, &list);
196 			spin_unlock_irqrestore(&schan->lock, flags);
197 
198 			/* Execute callbacks and run dependencies */
199 			list_for_each_entry(sdesc, &list, node) {
200 				desc = &sdesc->desc;
201 
202 				if (desc->callback)
203 					desc->callback(desc->callback_param);
204 
205 				last_cookie = desc->cookie;
206 				dma_run_dependencies(desc);
207 			}
208 
209 			/* Free descriptors */
210 			spin_lock_irqsave(&schan->lock, flags);
211 			list_splice_tail_init(&list, &schan->free);
212 			schan->chan.completed_cookie = last_cookie;
213 			spin_unlock_irqrestore(&schan->lock, flags);
214 		} else {
215 			/* for cyclic channel, desc is always in active list */
216 			sdesc = list_first_entry(&schan->active, struct sirfsoc_dma_desc,
217 				node);
218 
219 			if (!sdesc || (sdesc && !sdesc->cyclic)) {
220 				/* without active cyclic DMA */
221 				spin_unlock_irqrestore(&schan->lock, flags);
222 				continue;
223 			}
224 
225 			/* cyclic DMA */
226 			happened_cyclic = schan->happened_cyclic;
227 			spin_unlock_irqrestore(&schan->lock, flags);
228 
229 			desc = &sdesc->desc;
230 			while (happened_cyclic != schan->completed_cyclic) {
231 				if (desc->callback)
232 					desc->callback(desc->callback_param);
233 				schan->completed_cyclic++;
234 			}
235 		}
236 	}
237 }
238 
239 /* DMA Tasklet */
sirfsoc_dma_tasklet(unsigned long data)240 static void sirfsoc_dma_tasklet(unsigned long data)
241 {
242 	struct sirfsoc_dma *sdma = (void *)data;
243 
244 	sirfsoc_dma_process_completed(sdma);
245 }
246 
247 /* Submit descriptor to hardware */
sirfsoc_dma_tx_submit(struct dma_async_tx_descriptor * txd)248 static dma_cookie_t sirfsoc_dma_tx_submit(struct dma_async_tx_descriptor *txd)
249 {
250 	struct sirfsoc_dma_chan *schan = dma_chan_to_sirfsoc_dma_chan(txd->chan);
251 	struct sirfsoc_dma_desc *sdesc;
252 	unsigned long flags;
253 	dma_cookie_t cookie;
254 
255 	sdesc = container_of(txd, struct sirfsoc_dma_desc, desc);
256 
257 	spin_lock_irqsave(&schan->lock, flags);
258 
259 	/* Move descriptor to queue */
260 	list_move_tail(&sdesc->node, &schan->queued);
261 
262 	cookie = dma_cookie_assign(txd);
263 
264 	spin_unlock_irqrestore(&schan->lock, flags);
265 
266 	return cookie;
267 }
268 
sirfsoc_dma_slave_config(struct sirfsoc_dma_chan * schan,struct dma_slave_config * config)269 static int sirfsoc_dma_slave_config(struct sirfsoc_dma_chan *schan,
270 	struct dma_slave_config *config)
271 {
272 	unsigned long flags;
273 
274 	if ((config->src_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES) ||
275 		(config->dst_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES))
276 		return -EINVAL;
277 
278 	spin_lock_irqsave(&schan->lock, flags);
279 	schan->mode = (config->src_maxburst == 4 ? 1 : 0);
280 	spin_unlock_irqrestore(&schan->lock, flags);
281 
282 	return 0;
283 }
284 
sirfsoc_dma_terminate_all(struct sirfsoc_dma_chan * schan)285 static int sirfsoc_dma_terminate_all(struct sirfsoc_dma_chan *schan)
286 {
287 	struct sirfsoc_dma *sdma = dma_chan_to_sirfsoc_dma(&schan->chan);
288 	int cid = schan->chan.chan_id;
289 	unsigned long flags;
290 
291 	writel_relaxed(readl_relaxed(sdma->base + SIRFSOC_DMA_INT_EN) &
292 		~(1 << cid), sdma->base + SIRFSOC_DMA_INT_EN);
293 	writel_relaxed(1 << cid, sdma->base + SIRFSOC_DMA_CH_VALID);
294 
295 	writel_relaxed(readl_relaxed(sdma->base + SIRFSOC_DMA_CH_LOOP_CTRL)
296 		& ~((1 << cid) | 1 << (cid + 16)),
297 			sdma->base + SIRFSOC_DMA_CH_LOOP_CTRL);
298 
299 	spin_lock_irqsave(&schan->lock, flags);
300 	list_splice_tail_init(&schan->active, &schan->free);
301 	list_splice_tail_init(&schan->queued, &schan->free);
302 	spin_unlock_irqrestore(&schan->lock, flags);
303 
304 	return 0;
305 }
306 
sirfsoc_dma_control(struct dma_chan * chan,enum dma_ctrl_cmd cmd,unsigned long arg)307 static int sirfsoc_dma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
308 	unsigned long arg)
309 {
310 	struct dma_slave_config *config;
311 	struct sirfsoc_dma_chan *schan = dma_chan_to_sirfsoc_dma_chan(chan);
312 
313 	switch (cmd) {
314 	case DMA_TERMINATE_ALL:
315 		return sirfsoc_dma_terminate_all(schan);
316 	case DMA_SLAVE_CONFIG:
317 		config = (struct dma_slave_config *)arg;
318 		return sirfsoc_dma_slave_config(schan, config);
319 
320 	default:
321 		break;
322 	}
323 
324 	return -ENOSYS;
325 }
326 
327 /* Alloc channel resources */
sirfsoc_dma_alloc_chan_resources(struct dma_chan * chan)328 static int sirfsoc_dma_alloc_chan_resources(struct dma_chan *chan)
329 {
330 	struct sirfsoc_dma *sdma = dma_chan_to_sirfsoc_dma(chan);
331 	struct sirfsoc_dma_chan *schan = dma_chan_to_sirfsoc_dma_chan(chan);
332 	struct sirfsoc_dma_desc *sdesc;
333 	unsigned long flags;
334 	LIST_HEAD(descs);
335 	int i;
336 
337 	/* Alloc descriptors for this channel */
338 	for (i = 0; i < SIRFSOC_DMA_DESCRIPTORS; i++) {
339 		sdesc = kzalloc(sizeof(*sdesc), GFP_KERNEL);
340 		if (!sdesc) {
341 			dev_notice(sdma->dma.dev, "Memory allocation error. "
342 				"Allocated only %u descriptors\n", i);
343 			break;
344 		}
345 
346 		dma_async_tx_descriptor_init(&sdesc->desc, chan);
347 		sdesc->desc.flags = DMA_CTRL_ACK;
348 		sdesc->desc.tx_submit = sirfsoc_dma_tx_submit;
349 
350 		list_add_tail(&sdesc->node, &descs);
351 	}
352 
353 	/* Return error only if no descriptors were allocated */
354 	if (i == 0)
355 		return -ENOMEM;
356 
357 	spin_lock_irqsave(&schan->lock, flags);
358 
359 	list_splice_tail_init(&descs, &schan->free);
360 	spin_unlock_irqrestore(&schan->lock, flags);
361 
362 	return i;
363 }
364 
365 /* Free channel resources */
sirfsoc_dma_free_chan_resources(struct dma_chan * chan)366 static void sirfsoc_dma_free_chan_resources(struct dma_chan *chan)
367 {
368 	struct sirfsoc_dma_chan *schan = dma_chan_to_sirfsoc_dma_chan(chan);
369 	struct sirfsoc_dma_desc *sdesc, *tmp;
370 	unsigned long flags;
371 	LIST_HEAD(descs);
372 
373 	spin_lock_irqsave(&schan->lock, flags);
374 
375 	/* Channel must be idle */
376 	BUG_ON(!list_empty(&schan->prepared));
377 	BUG_ON(!list_empty(&schan->queued));
378 	BUG_ON(!list_empty(&schan->active));
379 	BUG_ON(!list_empty(&schan->completed));
380 
381 	/* Move data */
382 	list_splice_tail_init(&schan->free, &descs);
383 
384 	spin_unlock_irqrestore(&schan->lock, flags);
385 
386 	/* Free descriptors */
387 	list_for_each_entry_safe(sdesc, tmp, &descs, node)
388 		kfree(sdesc);
389 }
390 
391 /* Send pending descriptor to hardware */
sirfsoc_dma_issue_pending(struct dma_chan * chan)392 static void sirfsoc_dma_issue_pending(struct dma_chan *chan)
393 {
394 	struct sirfsoc_dma_chan *schan = dma_chan_to_sirfsoc_dma_chan(chan);
395 	unsigned long flags;
396 
397 	spin_lock_irqsave(&schan->lock, flags);
398 
399 	if (list_empty(&schan->active) && !list_empty(&schan->queued))
400 		sirfsoc_dma_execute(schan);
401 
402 	spin_unlock_irqrestore(&schan->lock, flags);
403 }
404 
405 /* Check request completion status */
406 static enum dma_status
sirfsoc_dma_tx_status(struct dma_chan * chan,dma_cookie_t cookie,struct dma_tx_state * txstate)407 sirfsoc_dma_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
408 	struct dma_tx_state *txstate)
409 {
410 	struct sirfsoc_dma_chan *schan = dma_chan_to_sirfsoc_dma_chan(chan);
411 	unsigned long flags;
412 	enum dma_status ret;
413 
414 	spin_lock_irqsave(&schan->lock, flags);
415 	ret = dma_cookie_status(chan, cookie, txstate);
416 	spin_unlock_irqrestore(&schan->lock, flags);
417 
418 	return ret;
419 }
420 
sirfsoc_dma_prep_interleaved(struct dma_chan * chan,struct dma_interleaved_template * xt,unsigned long flags)421 static struct dma_async_tx_descriptor *sirfsoc_dma_prep_interleaved(
422 	struct dma_chan *chan, struct dma_interleaved_template *xt,
423 	unsigned long flags)
424 {
425 	struct sirfsoc_dma *sdma = dma_chan_to_sirfsoc_dma(chan);
426 	struct sirfsoc_dma_chan *schan = dma_chan_to_sirfsoc_dma_chan(chan);
427 	struct sirfsoc_dma_desc *sdesc = NULL;
428 	unsigned long iflags;
429 	int ret;
430 
431 	if ((xt->dir != DMA_MEM_TO_DEV) && (xt->dir != DMA_DEV_TO_MEM)) {
432 		ret = -EINVAL;
433 		goto err_dir;
434 	}
435 
436 	/* Get free descriptor */
437 	spin_lock_irqsave(&schan->lock, iflags);
438 	if (!list_empty(&schan->free)) {
439 		sdesc = list_first_entry(&schan->free, struct sirfsoc_dma_desc,
440 			node);
441 		list_del(&sdesc->node);
442 	}
443 	spin_unlock_irqrestore(&schan->lock, iflags);
444 
445 	if (!sdesc) {
446 		/* try to free completed descriptors */
447 		sirfsoc_dma_process_completed(sdma);
448 		ret = 0;
449 		goto no_desc;
450 	}
451 
452 	/* Place descriptor in prepared list */
453 	spin_lock_irqsave(&schan->lock, iflags);
454 
455 	/*
456 	 * Number of chunks in a frame can only be 1 for prima2
457 	 * and ylen (number of frame - 1) must be at least 0
458 	 */
459 	if ((xt->frame_size == 1) && (xt->numf > 0)) {
460 		sdesc->cyclic = 0;
461 		sdesc->xlen = xt->sgl[0].size / SIRFSOC_DMA_WORD_LEN;
462 		sdesc->width = (xt->sgl[0].size + xt->sgl[0].icg) /
463 				SIRFSOC_DMA_WORD_LEN;
464 		sdesc->ylen = xt->numf - 1;
465 		if (xt->dir == DMA_MEM_TO_DEV) {
466 			sdesc->addr = xt->src_start;
467 			sdesc->dir = 1;
468 		} else {
469 			sdesc->addr = xt->dst_start;
470 			sdesc->dir = 0;
471 		}
472 
473 		list_add_tail(&sdesc->node, &schan->prepared);
474 	} else {
475 		pr_err("sirfsoc DMA Invalid xfer\n");
476 		ret = -EINVAL;
477 		goto err_xfer;
478 	}
479 	spin_unlock_irqrestore(&schan->lock, iflags);
480 
481 	return &sdesc->desc;
482 err_xfer:
483 	spin_unlock_irqrestore(&schan->lock, iflags);
484 no_desc:
485 err_dir:
486 	return ERR_PTR(ret);
487 }
488 
489 static struct dma_async_tx_descriptor *
sirfsoc_dma_prep_cyclic(struct dma_chan * chan,dma_addr_t addr,size_t buf_len,size_t period_len,enum dma_transfer_direction direction,void * context)490 sirfsoc_dma_prep_cyclic(struct dma_chan *chan, dma_addr_t addr,
491 	size_t buf_len, size_t period_len,
492 	enum dma_transfer_direction direction, void *context)
493 {
494 	struct sirfsoc_dma_chan *schan = dma_chan_to_sirfsoc_dma_chan(chan);
495 	struct sirfsoc_dma_desc *sdesc = NULL;
496 	unsigned long iflags;
497 
498 	/*
499 	 * we only support cycle transfer with 2 period
500 	 * If the X-length is set to 0, it would be the loop mode.
501 	 * The DMA address keeps increasing until reaching the end of a loop
502 	 * area whose size is defined by (DMA_WIDTH x (Y_LENGTH + 1)). Then
503 	 * the DMA address goes back to the beginning of this area.
504 	 * In loop mode, the DMA data region is divided into two parts, BUFA
505 	 * and BUFB. DMA controller generates interrupts twice in each loop:
506 	 * when the DMA address reaches the end of BUFA or the end of the
507 	 * BUFB
508 	 */
509 	if (buf_len !=  2 * period_len)
510 		return ERR_PTR(-EINVAL);
511 
512 	/* Get free descriptor */
513 	spin_lock_irqsave(&schan->lock, iflags);
514 	if (!list_empty(&schan->free)) {
515 		sdesc = list_first_entry(&schan->free, struct sirfsoc_dma_desc,
516 			node);
517 		list_del(&sdesc->node);
518 	}
519 	spin_unlock_irqrestore(&schan->lock, iflags);
520 
521 	if (!sdesc)
522 		return 0;
523 
524 	/* Place descriptor in prepared list */
525 	spin_lock_irqsave(&schan->lock, iflags);
526 	sdesc->addr = addr;
527 	sdesc->cyclic = 1;
528 	sdesc->xlen = 0;
529 	sdesc->ylen = buf_len / SIRFSOC_DMA_WORD_LEN - 1;
530 	sdesc->width = 1;
531 	list_add_tail(&sdesc->node, &schan->prepared);
532 	spin_unlock_irqrestore(&schan->lock, iflags);
533 
534 	return &sdesc->desc;
535 }
536 
537 /*
538  * The DMA controller consists of 16 independent DMA channels.
539  * Each channel is allocated to a different function
540  */
sirfsoc_dma_filter_id(struct dma_chan * chan,void * chan_id)541 bool sirfsoc_dma_filter_id(struct dma_chan *chan, void *chan_id)
542 {
543 	unsigned int ch_nr = (unsigned int) chan_id;
544 
545 	if (ch_nr == chan->chan_id +
546 		chan->device->dev_id * SIRFSOC_DMA_CHANNELS)
547 		return true;
548 
549 	return false;
550 }
551 EXPORT_SYMBOL(sirfsoc_dma_filter_id);
552 
sirfsoc_dma_probe(struct platform_device * op)553 static int __devinit sirfsoc_dma_probe(struct platform_device *op)
554 {
555 	struct device_node *dn = op->dev.of_node;
556 	struct device *dev = &op->dev;
557 	struct dma_device *dma;
558 	struct sirfsoc_dma *sdma;
559 	struct sirfsoc_dma_chan *schan;
560 	struct resource res;
561 	ulong regs_start, regs_size;
562 	u32 id;
563 	int ret, i;
564 
565 	sdma = devm_kzalloc(dev, sizeof(*sdma), GFP_KERNEL);
566 	if (!sdma) {
567 		dev_err(dev, "Memory exhausted!\n");
568 		return -ENOMEM;
569 	}
570 
571 	if (of_property_read_u32(dn, "cell-index", &id)) {
572 		dev_err(dev, "Fail to get DMAC index\n");
573 		ret = -ENODEV;
574 		goto free_mem;
575 	}
576 
577 	sdma->irq = irq_of_parse_and_map(dn, 0);
578 	if (sdma->irq == NO_IRQ) {
579 		dev_err(dev, "Error mapping IRQ!\n");
580 		ret = -EINVAL;
581 		goto free_mem;
582 	}
583 
584 	ret = of_address_to_resource(dn, 0, &res);
585 	if (ret) {
586 		dev_err(dev, "Error parsing memory region!\n");
587 		goto free_mem;
588 	}
589 
590 	regs_start = res.start;
591 	regs_size = resource_size(&res);
592 
593 	sdma->base = devm_ioremap(dev, regs_start, regs_size);
594 	if (!sdma->base) {
595 		dev_err(dev, "Error mapping memory region!\n");
596 		ret = -ENOMEM;
597 		goto irq_dispose;
598 	}
599 
600 	ret = devm_request_irq(dev, sdma->irq, &sirfsoc_dma_irq, 0, DRV_NAME,
601 		sdma);
602 	if (ret) {
603 		dev_err(dev, "Error requesting IRQ!\n");
604 		ret = -EINVAL;
605 		goto unmap_mem;
606 	}
607 
608 	dma = &sdma->dma;
609 	dma->dev = dev;
610 	dma->chancnt = SIRFSOC_DMA_CHANNELS;
611 
612 	dma->device_alloc_chan_resources = sirfsoc_dma_alloc_chan_resources;
613 	dma->device_free_chan_resources = sirfsoc_dma_free_chan_resources;
614 	dma->device_issue_pending = sirfsoc_dma_issue_pending;
615 	dma->device_control = sirfsoc_dma_control;
616 	dma->device_tx_status = sirfsoc_dma_tx_status;
617 	dma->device_prep_interleaved_dma = sirfsoc_dma_prep_interleaved;
618 	dma->device_prep_dma_cyclic = sirfsoc_dma_prep_cyclic;
619 
620 	INIT_LIST_HEAD(&dma->channels);
621 	dma_cap_set(DMA_SLAVE, dma->cap_mask);
622 	dma_cap_set(DMA_CYCLIC, dma->cap_mask);
623 	dma_cap_set(DMA_INTERLEAVE, dma->cap_mask);
624 	dma_cap_set(DMA_PRIVATE, dma->cap_mask);
625 
626 	for (i = 0; i < dma->chancnt; i++) {
627 		schan = &sdma->channels[i];
628 
629 		schan->chan.device = dma;
630 		dma_cookie_init(&schan->chan);
631 
632 		INIT_LIST_HEAD(&schan->free);
633 		INIT_LIST_HEAD(&schan->prepared);
634 		INIT_LIST_HEAD(&schan->queued);
635 		INIT_LIST_HEAD(&schan->active);
636 		INIT_LIST_HEAD(&schan->completed);
637 
638 		spin_lock_init(&schan->lock);
639 		list_add_tail(&schan->chan.device_node, &dma->channels);
640 	}
641 
642 	tasklet_init(&sdma->tasklet, sirfsoc_dma_tasklet, (unsigned long)sdma);
643 
644 	/* Register DMA engine */
645 	dev_set_drvdata(dev, sdma);
646 	ret = dma_async_device_register(dma);
647 	if (ret)
648 		goto free_irq;
649 
650 	dev_info(dev, "initialized SIRFSOC DMAC driver\n");
651 
652 	return 0;
653 
654 free_irq:
655 	devm_free_irq(dev, sdma->irq, sdma);
656 irq_dispose:
657 	irq_dispose_mapping(sdma->irq);
658 unmap_mem:
659 	iounmap(sdma->base);
660 free_mem:
661 	devm_kfree(dev, sdma);
662 	return ret;
663 }
664 
sirfsoc_dma_remove(struct platform_device * op)665 static int __devexit sirfsoc_dma_remove(struct platform_device *op)
666 {
667 	struct device *dev = &op->dev;
668 	struct sirfsoc_dma *sdma = dev_get_drvdata(dev);
669 
670 	dma_async_device_unregister(&sdma->dma);
671 	devm_free_irq(dev, sdma->irq, sdma);
672 	irq_dispose_mapping(sdma->irq);
673 	iounmap(sdma->base);
674 	devm_kfree(dev, sdma);
675 	return 0;
676 }
677 
678 static struct of_device_id sirfsoc_dma_match[] = {
679 	{ .compatible = "sirf,prima2-dmac", },
680 	{},
681 };
682 
683 static struct platform_driver sirfsoc_dma_driver = {
684 	.probe		= sirfsoc_dma_probe,
685 	.remove		= __devexit_p(sirfsoc_dma_remove),
686 	.driver = {
687 		.name = DRV_NAME,
688 		.owner = THIS_MODULE,
689 		.of_match_table	= sirfsoc_dma_match,
690 	},
691 };
692 
693 module_platform_driver(sirfsoc_dma_driver);
694 
695 MODULE_AUTHOR("Rongjun Ying <rongjun.ying@csr.com>, "
696 	"Barry Song <baohua.song@csr.com>");
697 MODULE_DESCRIPTION("SIRFSOC DMA control driver");
698 MODULE_LICENSE("GPL v2");
699