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  1/*
  2 *  Copyright (C) 2013, Lars-Peter Clausen <lars@metafoo.de>
  3 *  JZ4740 DMAC support
  4 *
  5 *  This program is free software; you can redistribute it and/or modify it
  6 *  under  the terms of the GNU General	 Public License as published by the
  7 *  Free Software Foundation;  either version 2 of the License, or (at your
  8 *  option) any later version.
  9 *
 10 *  You should have received a copy of the GNU General Public License along
 11 *  with this program; if not, write to the Free Software Foundation, Inc.,
 12 *  675 Mass Ave, Cambridge, MA 02139, USA.
 13 *
 14 */
 15
 16#include <linux/dmaengine.h>
 17#include <linux/dma-mapping.h>
 18#include <linux/err.h>
 19#include <linux/init.h>
 20#include <linux/list.h>
 21#include <linux/module.h>
 22#include <linux/platform_device.h>
 23#include <linux/slab.h>
 24#include <linux/spinlock.h>
 25#include <linux/irq.h>
 26#include <linux/clk.h>
 27
 28#include <asm/mach-jz4740/dma.h>
 29
 30#include "virt-dma.h"
 31
 32#define JZ_DMA_NR_CHANS 6
 33
 34#define JZ_REG_DMA_SRC_ADDR(x)		(0x00 + (x) * 0x20)
 35#define JZ_REG_DMA_DST_ADDR(x)		(0x04 + (x) * 0x20)
 36#define JZ_REG_DMA_TRANSFER_COUNT(x)	(0x08 + (x) * 0x20)
 37#define JZ_REG_DMA_REQ_TYPE(x)		(0x0C + (x) * 0x20)
 38#define JZ_REG_DMA_STATUS_CTRL(x)	(0x10 + (x) * 0x20)
 39#define JZ_REG_DMA_CMD(x)		(0x14 + (x) * 0x20)
 40#define JZ_REG_DMA_DESC_ADDR(x)		(0x18 + (x) * 0x20)
 41
 42#define JZ_REG_DMA_CTRL			0x300
 43#define JZ_REG_DMA_IRQ			0x304
 44#define JZ_REG_DMA_DOORBELL		0x308
 45#define JZ_REG_DMA_DOORBELL_SET		0x30C
 46
 47#define JZ_DMA_STATUS_CTRL_NO_DESC		BIT(31)
 48#define JZ_DMA_STATUS_CTRL_DESC_INV		BIT(6)
 49#define JZ_DMA_STATUS_CTRL_ADDR_ERR		BIT(4)
 50#define JZ_DMA_STATUS_CTRL_TRANSFER_DONE	BIT(3)
 51#define JZ_DMA_STATUS_CTRL_HALT			BIT(2)
 52#define JZ_DMA_STATUS_CTRL_COUNT_TERMINATE	BIT(1)
 53#define JZ_DMA_STATUS_CTRL_ENABLE		BIT(0)
 54
 55#define JZ_DMA_CMD_SRC_INC			BIT(23)
 56#define JZ_DMA_CMD_DST_INC			BIT(22)
 57#define JZ_DMA_CMD_RDIL_MASK			(0xf << 16)
 58#define JZ_DMA_CMD_SRC_WIDTH_MASK		(0x3 << 14)
 59#define JZ_DMA_CMD_DST_WIDTH_MASK		(0x3 << 12)
 60#define JZ_DMA_CMD_INTERVAL_LENGTH_MASK		(0x7 << 8)
 61#define JZ_DMA_CMD_BLOCK_MODE			BIT(7)
 62#define JZ_DMA_CMD_DESC_VALID			BIT(4)
 63#define JZ_DMA_CMD_DESC_VALID_MODE		BIT(3)
 64#define JZ_DMA_CMD_VALID_IRQ_ENABLE		BIT(2)
 65#define JZ_DMA_CMD_TRANSFER_IRQ_ENABLE		BIT(1)
 66#define JZ_DMA_CMD_LINK_ENABLE			BIT(0)
 67
 68#define JZ_DMA_CMD_FLAGS_OFFSET 22
 69#define JZ_DMA_CMD_RDIL_OFFSET 16
 70#define JZ_DMA_CMD_SRC_WIDTH_OFFSET 14
 71#define JZ_DMA_CMD_DST_WIDTH_OFFSET 12
 72#define JZ_DMA_CMD_TRANSFER_SIZE_OFFSET 8
 73#define JZ_DMA_CMD_MODE_OFFSET 7
 74
 75#define JZ_DMA_CTRL_PRIORITY_MASK		(0x3 << 8)
 76#define JZ_DMA_CTRL_HALT			BIT(3)
 77#define JZ_DMA_CTRL_ADDRESS_ERROR		BIT(2)
 78#define JZ_DMA_CTRL_ENABLE			BIT(0)
 79
 80enum jz4740_dma_width {
 81	JZ4740_DMA_WIDTH_32BIT	= 0,
 82	JZ4740_DMA_WIDTH_8BIT	= 1,
 83	JZ4740_DMA_WIDTH_16BIT	= 2,
 84};
 85
 86enum jz4740_dma_transfer_size {
 87	JZ4740_DMA_TRANSFER_SIZE_4BYTE	= 0,
 88	JZ4740_DMA_TRANSFER_SIZE_1BYTE	= 1,
 89	JZ4740_DMA_TRANSFER_SIZE_2BYTE	= 2,
 90	JZ4740_DMA_TRANSFER_SIZE_16BYTE = 3,
 91	JZ4740_DMA_TRANSFER_SIZE_32BYTE = 4,
 92};
 93
 94enum jz4740_dma_flags {
 95	JZ4740_DMA_SRC_AUTOINC = 0x2,
 96	JZ4740_DMA_DST_AUTOINC = 0x1,
 97};
 98
 99enum jz4740_dma_mode {
100	JZ4740_DMA_MODE_SINGLE	= 0,
101	JZ4740_DMA_MODE_BLOCK	= 1,
102};
103
104struct jz4740_dma_sg {
105	dma_addr_t addr;
106	unsigned int len;
107};
108
109struct jz4740_dma_desc {
110	struct virt_dma_desc vdesc;
111
112	enum dma_transfer_direction direction;
113	bool cyclic;
114
115	unsigned int num_sgs;
116	struct jz4740_dma_sg sg[];
117};
118
119struct jz4740_dmaengine_chan {
120	struct virt_dma_chan vchan;
121	unsigned int id;
122
123	dma_addr_t fifo_addr;
124	unsigned int transfer_shift;
125
126	struct jz4740_dma_desc *desc;
127	unsigned int next_sg;
128};
129
130struct jz4740_dma_dev {
131	struct dma_device ddev;
132	void __iomem *base;
133	struct clk *clk;
134
135	struct jz4740_dmaengine_chan chan[JZ_DMA_NR_CHANS];
136};
137
138static struct jz4740_dma_dev *jz4740_dma_chan_get_dev(
139	struct jz4740_dmaengine_chan *chan)
140{
141	return container_of(chan->vchan.chan.device, struct jz4740_dma_dev,
142		ddev);
143}
144
145static struct jz4740_dmaengine_chan *to_jz4740_dma_chan(struct dma_chan *c)
146{
147	return container_of(c, struct jz4740_dmaengine_chan, vchan.chan);
148}
149
150static struct jz4740_dma_desc *to_jz4740_dma_desc(struct virt_dma_desc *vdesc)
151{
152	return container_of(vdesc, struct jz4740_dma_desc, vdesc);
153}
154
155static inline uint32_t jz4740_dma_read(struct jz4740_dma_dev *dmadev,
156	unsigned int reg)
157{
158	return readl(dmadev->base + reg);
159}
160
161static inline void jz4740_dma_write(struct jz4740_dma_dev *dmadev,
162	unsigned reg, uint32_t val)
163{
164	writel(val, dmadev->base + reg);
165}
166
167static inline void jz4740_dma_write_mask(struct jz4740_dma_dev *dmadev,
168	unsigned int reg, uint32_t val, uint32_t mask)
169{
170	uint32_t tmp;
171
172	tmp = jz4740_dma_read(dmadev, reg);
173	tmp &= ~mask;
174	tmp |= val;
175	jz4740_dma_write(dmadev, reg, tmp);
176}
177
178static struct jz4740_dma_desc *jz4740_dma_alloc_desc(unsigned int num_sgs)
179{
180	return kzalloc(sizeof(struct jz4740_dma_desc) +
181		sizeof(struct jz4740_dma_sg) * num_sgs, GFP_ATOMIC);
182}
183
184static enum jz4740_dma_width jz4740_dma_width(enum dma_slave_buswidth width)
185{
186	switch (width) {
187	case DMA_SLAVE_BUSWIDTH_1_BYTE:
188		return JZ4740_DMA_WIDTH_8BIT;
189	case DMA_SLAVE_BUSWIDTH_2_BYTES:
190		return JZ4740_DMA_WIDTH_16BIT;
191	case DMA_SLAVE_BUSWIDTH_4_BYTES:
192		return JZ4740_DMA_WIDTH_32BIT;
193	default:
194		return JZ4740_DMA_WIDTH_32BIT;
195	}
196}
197
198static enum jz4740_dma_transfer_size jz4740_dma_maxburst(u32 maxburst)
199{
200	if (maxburst <= 1)
201		return JZ4740_DMA_TRANSFER_SIZE_1BYTE;
202	else if (maxburst <= 3)
203		return JZ4740_DMA_TRANSFER_SIZE_2BYTE;
204	else if (maxburst <= 15)
205		return JZ4740_DMA_TRANSFER_SIZE_4BYTE;
206	else if (maxburst <= 31)
207		return JZ4740_DMA_TRANSFER_SIZE_16BYTE;
208
209	return JZ4740_DMA_TRANSFER_SIZE_32BYTE;
210}
211
212static int jz4740_dma_slave_config(struct dma_chan *c,
213	const struct dma_slave_config *config)
214{
215	struct jz4740_dmaengine_chan *chan = to_jz4740_dma_chan(c);
216	struct jz4740_dma_dev *dmadev = jz4740_dma_chan_get_dev(chan);
217	enum jz4740_dma_width src_width;
218	enum jz4740_dma_width dst_width;
219	enum jz4740_dma_transfer_size transfer_size;
220	enum jz4740_dma_flags flags;
221	uint32_t cmd;
222
223	switch (config->direction) {
224	case DMA_MEM_TO_DEV:
225		flags = JZ4740_DMA_SRC_AUTOINC;
226		transfer_size = jz4740_dma_maxburst(config->dst_maxburst);
227		chan->fifo_addr = config->dst_addr;
228		break;
229	case DMA_DEV_TO_MEM:
230		flags = JZ4740_DMA_DST_AUTOINC;
231		transfer_size = jz4740_dma_maxburst(config->src_maxburst);
232		chan->fifo_addr = config->src_addr;
233		break;
234	default:
235		return -EINVAL;
236	}
237
238	src_width = jz4740_dma_width(config->src_addr_width);
239	dst_width = jz4740_dma_width(config->dst_addr_width);
240
241	switch (transfer_size) {
242	case JZ4740_DMA_TRANSFER_SIZE_2BYTE:
243		chan->transfer_shift = 1;
244		break;
245	case JZ4740_DMA_TRANSFER_SIZE_4BYTE:
246		chan->transfer_shift = 2;
247		break;
248	case JZ4740_DMA_TRANSFER_SIZE_16BYTE:
249		chan->transfer_shift = 4;
250		break;
251	case JZ4740_DMA_TRANSFER_SIZE_32BYTE:
252		chan->transfer_shift = 5;
253		break;
254	default:
255		chan->transfer_shift = 0;
256		break;
257	}
258
259	cmd = flags << JZ_DMA_CMD_FLAGS_OFFSET;
260	cmd |= src_width << JZ_DMA_CMD_SRC_WIDTH_OFFSET;
261	cmd |= dst_width << JZ_DMA_CMD_DST_WIDTH_OFFSET;
262	cmd |= transfer_size << JZ_DMA_CMD_TRANSFER_SIZE_OFFSET;
263	cmd |= JZ4740_DMA_MODE_SINGLE << JZ_DMA_CMD_MODE_OFFSET;
264	cmd |= JZ_DMA_CMD_TRANSFER_IRQ_ENABLE;
265
266	jz4740_dma_write(dmadev, JZ_REG_DMA_CMD(chan->id), cmd);
267	jz4740_dma_write(dmadev, JZ_REG_DMA_STATUS_CTRL(chan->id), 0);
268	jz4740_dma_write(dmadev, JZ_REG_DMA_REQ_TYPE(chan->id),
269		config->slave_id);
270
271	return 0;
272}
273
274static int jz4740_dma_terminate_all(struct dma_chan *c)
275{
276	struct jz4740_dmaengine_chan *chan = to_jz4740_dma_chan(c);
277	struct jz4740_dma_dev *dmadev = jz4740_dma_chan_get_dev(chan);
278	unsigned long flags;
279	LIST_HEAD(head);
280
281	spin_lock_irqsave(&chan->vchan.lock, flags);
282	jz4740_dma_write_mask(dmadev, JZ_REG_DMA_STATUS_CTRL(chan->id), 0,
283			JZ_DMA_STATUS_CTRL_ENABLE);
284	chan->desc = NULL;
285	vchan_get_all_descriptors(&chan->vchan, &head);
286	spin_unlock_irqrestore(&chan->vchan.lock, flags);
287
288	vchan_dma_desc_free_list(&chan->vchan, &head);
289
290	return 0;
291}
292
293static int jz4740_dma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
294	unsigned long arg)
295{
296	struct dma_slave_config *config = (struct dma_slave_config *)arg;
297
298	switch (cmd) {
299	case DMA_SLAVE_CONFIG:
300		return jz4740_dma_slave_config(chan, config);
301	case DMA_TERMINATE_ALL:
302		return jz4740_dma_terminate_all(chan);
303	default:
304		return -ENOSYS;
305	}
306}
307
308static int jz4740_dma_start_transfer(struct jz4740_dmaengine_chan *chan)
309{
310	struct jz4740_dma_dev *dmadev = jz4740_dma_chan_get_dev(chan);
311	dma_addr_t src_addr, dst_addr;
312	struct virt_dma_desc *vdesc;
313	struct jz4740_dma_sg *sg;
314
315	jz4740_dma_write_mask(dmadev, JZ_REG_DMA_STATUS_CTRL(chan->id), 0,
316			JZ_DMA_STATUS_CTRL_ENABLE);
317
318	if (!chan->desc) {
319		vdesc = vchan_next_desc(&chan->vchan);
320		if (!vdesc)
321			return 0;
322		chan->desc = to_jz4740_dma_desc(vdesc);
323		chan->next_sg = 0;
324	}
325
326	if (chan->next_sg == chan->desc->num_sgs)
327		chan->next_sg = 0;
328
329	sg = &chan->desc->sg[chan->next_sg];
330
331	if (chan->desc->direction == DMA_MEM_TO_DEV) {
332		src_addr = sg->addr;
333		dst_addr = chan->fifo_addr;
334	} else {
335		src_addr = chan->fifo_addr;
336		dst_addr = sg->addr;
337	}
338	jz4740_dma_write(dmadev, JZ_REG_DMA_SRC_ADDR(chan->id), src_addr);
339	jz4740_dma_write(dmadev, JZ_REG_DMA_DST_ADDR(chan->id), dst_addr);
340	jz4740_dma_write(dmadev, JZ_REG_DMA_TRANSFER_COUNT(chan->id),
341			sg->len >> chan->transfer_shift);
342
343	chan->next_sg++;
344
345	jz4740_dma_write_mask(dmadev, JZ_REG_DMA_STATUS_CTRL(chan->id),
346			JZ_DMA_STATUS_CTRL_NO_DESC | JZ_DMA_STATUS_CTRL_ENABLE,
347			JZ_DMA_STATUS_CTRL_HALT | JZ_DMA_STATUS_CTRL_NO_DESC |
348			JZ_DMA_STATUS_CTRL_ENABLE);
349
350	jz4740_dma_write_mask(dmadev, JZ_REG_DMA_CTRL,
351			JZ_DMA_CTRL_ENABLE,
352			JZ_DMA_CTRL_HALT | JZ_DMA_CTRL_ENABLE);
353
354	return 0;
355}
356
357static void jz4740_dma_chan_irq(struct jz4740_dmaengine_chan *chan)
358{
359	spin_lock(&chan->vchan.lock);
360	if (chan->desc) {
361		if (chan->desc && chan->desc->cyclic) {
362			vchan_cyclic_callback(&chan->desc->vdesc);
363		} else {
364			if (chan->next_sg == chan->desc->num_sgs) {
365				chan->desc = NULL;
366				vchan_cookie_complete(&chan->desc->vdesc);
367			}
368		}
369	}
370	jz4740_dma_start_transfer(chan);
371	spin_unlock(&chan->vchan.lock);
372}
373
374static irqreturn_t jz4740_dma_irq(int irq, void *devid)
375{
376	struct jz4740_dma_dev *dmadev = devid;
377	uint32_t irq_status;
378	unsigned int i;
379
380	irq_status = readl(dmadev->base + JZ_REG_DMA_IRQ);
381
382	for (i = 0; i < 6; ++i) {
383		if (irq_status & (1 << i)) {
384			jz4740_dma_write_mask(dmadev,
385				JZ_REG_DMA_STATUS_CTRL(i), 0,
386				JZ_DMA_STATUS_CTRL_ENABLE |
387				JZ_DMA_STATUS_CTRL_TRANSFER_DONE);
388
389			jz4740_dma_chan_irq(&dmadev->chan[i]);
390		}
391	}
392
393	return IRQ_HANDLED;
394}
395
396static void jz4740_dma_issue_pending(struct dma_chan *c)
397{
398	struct jz4740_dmaengine_chan *chan = to_jz4740_dma_chan(c);
399	unsigned long flags;
400
401	spin_lock_irqsave(&chan->vchan.lock, flags);
402	if (vchan_issue_pending(&chan->vchan) && !chan->desc)
403		jz4740_dma_start_transfer(chan);
404	spin_unlock_irqrestore(&chan->vchan.lock, flags);
405}
406
407static struct dma_async_tx_descriptor *jz4740_dma_prep_slave_sg(
408	struct dma_chan *c, struct scatterlist *sgl,
409	unsigned int sg_len, enum dma_transfer_direction direction,
410	unsigned long flags, void *context)
411{
412	struct jz4740_dmaengine_chan *chan = to_jz4740_dma_chan(c);
413	struct jz4740_dma_desc *desc;
414	struct scatterlist *sg;
415	unsigned int i;
416
417	desc = jz4740_dma_alloc_desc(sg_len);
418	if (!desc)
419		return NULL;
420
421	for_each_sg(sgl, sg, sg_len, i) {
422		desc->sg[i].addr = sg_dma_address(sg);
423		desc->sg[i].len = sg_dma_len(sg);
424	}
425
426	desc->num_sgs = sg_len;
427	desc->direction = direction;
428	desc->cyclic = false;
429
430	return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
431}
432
433static struct dma_async_tx_descriptor *jz4740_dma_prep_dma_cyclic(
434	struct dma_chan *c, dma_addr_t buf_addr, size_t buf_len,
435	size_t period_len, enum dma_transfer_direction direction,
436	unsigned long flags, void *context)
437{
438	struct jz4740_dmaengine_chan *chan = to_jz4740_dma_chan(c);
439	struct jz4740_dma_desc *desc;
440	unsigned int num_periods, i;
441
442	if (buf_len % period_len)
443		return NULL;
444
445	num_periods = buf_len / period_len;
446
447	desc = jz4740_dma_alloc_desc(num_periods);
448	if (!desc)
449		return NULL;
450
451	for (i = 0; i < num_periods; i++) {
452		desc->sg[i].addr = buf_addr;
453		desc->sg[i].len = period_len;
454		buf_addr += period_len;
455	}
456
457	desc->num_sgs = num_periods;
458	desc->direction = direction;
459	desc->cyclic = true;
460
461	return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
462}
463
464static size_t jz4740_dma_desc_residue(struct jz4740_dmaengine_chan *chan,
465	struct jz4740_dma_desc *desc, unsigned int next_sg)
466{
467	struct jz4740_dma_dev *dmadev = jz4740_dma_chan_get_dev(chan);
468	unsigned int residue, count;
469	unsigned int i;
470
471	residue = 0;
472
473	for (i = next_sg; i < desc->num_sgs; i++)
474		residue += desc->sg[i].len;
475
476	if (next_sg != 0) {
477		count = jz4740_dma_read(dmadev,
478			JZ_REG_DMA_TRANSFER_COUNT(chan->id));
479		residue += count << chan->transfer_shift;
480	}
481
482	return residue;
483}
484
485static enum dma_status jz4740_dma_tx_status(struct dma_chan *c,
486	dma_cookie_t cookie, struct dma_tx_state *state)
487{
488	struct jz4740_dmaengine_chan *chan = to_jz4740_dma_chan(c);
489	struct virt_dma_desc *vdesc;
490	enum dma_status status;
491	unsigned long flags;
492
493	status = dma_cookie_status(c, cookie, state);
494	if (status == DMA_COMPLETE || !state)
495		return status;
496
497	spin_lock_irqsave(&chan->vchan.lock, flags);
498	vdesc = vchan_find_desc(&chan->vchan, cookie);
499	if (cookie == chan->desc->vdesc.tx.cookie) {
500		state->residue = jz4740_dma_desc_residue(chan, chan->desc,
501				chan->next_sg);
502	} else if (vdesc) {
503		state->residue = jz4740_dma_desc_residue(chan,
504				to_jz4740_dma_desc(vdesc), 0);
505	} else {
506		state->residue = 0;
507	}
508	spin_unlock_irqrestore(&chan->vchan.lock, flags);
509
510	return status;
511}
512
513static int jz4740_dma_alloc_chan_resources(struct dma_chan *c)
514{
515	return 0;
516}
517
518static void jz4740_dma_free_chan_resources(struct dma_chan *c)
519{
520	vchan_free_chan_resources(to_virt_chan(c));
521}
522
523static void jz4740_dma_desc_free(struct virt_dma_desc *vdesc)
524{
525	kfree(container_of(vdesc, struct jz4740_dma_desc, vdesc));
526}
527
528static int jz4740_dma_probe(struct platform_device *pdev)
529{
530	struct jz4740_dmaengine_chan *chan;
531	struct jz4740_dma_dev *dmadev;
532	struct dma_device *dd;
533	unsigned int i;
534	struct resource *res;
535	int ret;
536	int irq;
537
538	dmadev = devm_kzalloc(&pdev->dev, sizeof(*dmadev), GFP_KERNEL);
539	if (!dmadev)
540		return -EINVAL;
541
542	dd = &dmadev->ddev;
543
544	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
545	dmadev->base = devm_ioremap_resource(&pdev->dev, res);
546	if (IS_ERR(dmadev->base))
547		return PTR_ERR(dmadev->base);
548
549	dmadev->clk = clk_get(&pdev->dev, "dma");
550	if (IS_ERR(dmadev->clk))
551		return PTR_ERR(dmadev->clk);
552
553	clk_prepare_enable(dmadev->clk);
554
555	dma_cap_set(DMA_SLAVE, dd->cap_mask);
556	dma_cap_set(DMA_CYCLIC, dd->cap_mask);
557	dd->device_alloc_chan_resources = jz4740_dma_alloc_chan_resources;
558	dd->device_free_chan_resources = jz4740_dma_free_chan_resources;
559	dd->device_tx_status = jz4740_dma_tx_status;
560	dd->device_issue_pending = jz4740_dma_issue_pending;
561	dd->device_prep_slave_sg = jz4740_dma_prep_slave_sg;
562	dd->device_prep_dma_cyclic = jz4740_dma_prep_dma_cyclic;
563	dd->device_control = jz4740_dma_control;
564	dd->dev = &pdev->dev;
565	dd->chancnt = JZ_DMA_NR_CHANS;
566	INIT_LIST_HEAD(&dd->channels);
567
568	for (i = 0; i < dd->chancnt; i++) {
569		chan = &dmadev->chan[i];
570		chan->id = i;
571		chan->vchan.desc_free = jz4740_dma_desc_free;
572		vchan_init(&chan->vchan, dd);
573	}
574
575	ret = dma_async_device_register(dd);
576	if (ret)
577		return ret;
578
579	irq = platform_get_irq(pdev, 0);
580	ret = request_irq(irq, jz4740_dma_irq, 0, dev_name(&pdev->dev), dmadev);
581	if (ret)
582		goto err_unregister;
583
584	platform_set_drvdata(pdev, dmadev);
585
586	return 0;
587
588err_unregister:
589	dma_async_device_unregister(dd);
590	return ret;
591}
592
593static int jz4740_dma_remove(struct platform_device *pdev)
594{
595	struct jz4740_dma_dev *dmadev = platform_get_drvdata(pdev);
596	int irq = platform_get_irq(pdev, 0);
597
598	free_irq(irq, dmadev);
599	dma_async_device_unregister(&dmadev->ddev);
600	clk_disable_unprepare(dmadev->clk);
601
602	return 0;
603}
604
605static struct platform_driver jz4740_dma_driver = {
606	.probe = jz4740_dma_probe,
607	.remove = jz4740_dma_remove,
608	.driver = {
609		.name = "jz4740-dma",
610		.owner = THIS_MODULE,
611	},
612};
613module_platform_driver(jz4740_dma_driver);
614
615MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
616MODULE_DESCRIPTION("JZ4740 DMA driver");
617MODULE_LICENSE("GPLv2");