xref: /openbmc/linux/drivers/dma/owl-dma.c (revision c1d3fb8a)
1 // SPDX-License-Identifier: GPL-2.0+
2 //
3 // Actions Semi Owl SoCs DMA driver
4 //
5 // Copyright (c) 2014 Actions Semi Inc.
6 // Author: David Liu <liuwei@actions-semi.com>
7 //
8 // Copyright (c) 2018 Linaro Ltd.
9 // Author: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
10 
11 #include <linux/bitops.h>
12 #include <linux/clk.h>
13 #include <linux/delay.h>
14 #include <linux/dmaengine.h>
15 #include <linux/dma-mapping.h>
16 #include <linux/dmapool.h>
17 #include <linux/err.h>
18 #include <linux/init.h>
19 #include <linux/interrupt.h>
20 #include <linux/io.h>
21 #include <linux/mm.h>
22 #include <linux/module.h>
23 #include <linux/of_device.h>
24 #include <linux/of_dma.h>
25 #include <linux/slab.h>
26 #include "virt-dma.h"
27 
28 #define OWL_DMA_FRAME_MAX_LENGTH		0xfffff
29 
30 /* Global DMA Controller Registers */
31 #define OWL_DMA_IRQ_PD0				0x00
32 #define OWL_DMA_IRQ_PD1				0x04
33 #define OWL_DMA_IRQ_PD2				0x08
34 #define OWL_DMA_IRQ_PD3				0x0C
35 #define OWL_DMA_IRQ_EN0				0x10
36 #define OWL_DMA_IRQ_EN1				0x14
37 #define OWL_DMA_IRQ_EN2				0x18
38 #define OWL_DMA_IRQ_EN3				0x1C
39 #define OWL_DMA_SECURE_ACCESS_CTL		0x20
40 #define OWL_DMA_NIC_QOS				0x24
41 #define OWL_DMA_DBGSEL				0x28
42 #define OWL_DMA_IDLE_STAT			0x2C
43 
44 /* Channel Registers */
45 #define OWL_DMA_CHAN_BASE(i)			(0x100 + (i) * 0x100)
46 #define OWL_DMAX_MODE				0x00
47 #define OWL_DMAX_SOURCE				0x04
48 #define OWL_DMAX_DESTINATION			0x08
49 #define OWL_DMAX_FRAME_LEN			0x0C
50 #define OWL_DMAX_FRAME_CNT			0x10
51 #define OWL_DMAX_REMAIN_FRAME_CNT		0x14
52 #define OWL_DMAX_REMAIN_CNT			0x18
53 #define OWL_DMAX_SOURCE_STRIDE			0x1C
54 #define OWL_DMAX_DESTINATION_STRIDE		0x20
55 #define OWL_DMAX_START				0x24
56 #define OWL_DMAX_PAUSE				0x28
57 #define OWL_DMAX_CHAINED_CTL			0x2C
58 #define OWL_DMAX_CONSTANT			0x30
59 #define OWL_DMAX_LINKLIST_CTL			0x34
60 #define OWL_DMAX_NEXT_DESCRIPTOR		0x38
61 #define OWL_DMAX_CURRENT_DESCRIPTOR_NUM		0x3C
62 #define OWL_DMAX_INT_CTL			0x40
63 #define OWL_DMAX_INT_STATUS			0x44
64 #define OWL_DMAX_CURRENT_SOURCE_POINTER		0x48
65 #define OWL_DMAX_CURRENT_DESTINATION_POINTER	0x4C
66 
67 /* OWL_DMAX_MODE Bits */
68 #define OWL_DMA_MODE_TS(x)			(((x) & GENMASK(5, 0)) << 0)
69 #define OWL_DMA_MODE_ST(x)			(((x) & GENMASK(1, 0)) << 8)
70 #define	OWL_DMA_MODE_ST_DEV			OWL_DMA_MODE_ST(0)
71 #define	OWL_DMA_MODE_ST_DCU			OWL_DMA_MODE_ST(2)
72 #define	OWL_DMA_MODE_ST_SRAM			OWL_DMA_MODE_ST(3)
73 #define OWL_DMA_MODE_DT(x)			(((x) & GENMASK(1, 0)) << 10)
74 #define	OWL_DMA_MODE_DT_DEV			OWL_DMA_MODE_DT(0)
75 #define	OWL_DMA_MODE_DT_DCU			OWL_DMA_MODE_DT(2)
76 #define	OWL_DMA_MODE_DT_SRAM			OWL_DMA_MODE_DT(3)
77 #define OWL_DMA_MODE_SAM(x)			(((x) & GENMASK(1, 0)) << 16)
78 #define	OWL_DMA_MODE_SAM_CONST			OWL_DMA_MODE_SAM(0)
79 #define	OWL_DMA_MODE_SAM_INC			OWL_DMA_MODE_SAM(1)
80 #define	OWL_DMA_MODE_SAM_STRIDE			OWL_DMA_MODE_SAM(2)
81 #define OWL_DMA_MODE_DAM(x)			(((x) & GENMASK(1, 0)) << 18)
82 #define	OWL_DMA_MODE_DAM_CONST			OWL_DMA_MODE_DAM(0)
83 #define	OWL_DMA_MODE_DAM_INC			OWL_DMA_MODE_DAM(1)
84 #define	OWL_DMA_MODE_DAM_STRIDE			OWL_DMA_MODE_DAM(2)
85 #define OWL_DMA_MODE_PW(x)			(((x) & GENMASK(2, 0)) << 20)
86 #define OWL_DMA_MODE_CB				BIT(23)
87 #define OWL_DMA_MODE_NDDBW(x)			(((x) & 0x1) << 28)
88 #define	OWL_DMA_MODE_NDDBW_32BIT		OWL_DMA_MODE_NDDBW(0)
89 #define	OWL_DMA_MODE_NDDBW_8BIT			OWL_DMA_MODE_NDDBW(1)
90 #define OWL_DMA_MODE_CFE			BIT(29)
91 #define OWL_DMA_MODE_LME			BIT(30)
92 #define OWL_DMA_MODE_CME			BIT(31)
93 
94 /* OWL_DMAX_LINKLIST_CTL Bits */
95 #define OWL_DMA_LLC_SAV(x)			(((x) & GENMASK(1, 0)) << 8)
96 #define	OWL_DMA_LLC_SAV_INC			OWL_DMA_LLC_SAV(0)
97 #define	OWL_DMA_LLC_SAV_LOAD_NEXT		OWL_DMA_LLC_SAV(1)
98 #define	OWL_DMA_LLC_SAV_LOAD_PREV		OWL_DMA_LLC_SAV(2)
99 #define OWL_DMA_LLC_DAV(x)			(((x) & GENMASK(1, 0)) << 10)
100 #define	OWL_DMA_LLC_DAV_INC			OWL_DMA_LLC_DAV(0)
101 #define	OWL_DMA_LLC_DAV_LOAD_NEXT		OWL_DMA_LLC_DAV(1)
102 #define	OWL_DMA_LLC_DAV_LOAD_PREV		OWL_DMA_LLC_DAV(2)
103 #define OWL_DMA_LLC_SUSPEND			BIT(16)
104 
105 /* OWL_DMAX_INT_CTL Bits */
106 #define OWL_DMA_INTCTL_BLOCK			BIT(0)
107 #define OWL_DMA_INTCTL_SUPER_BLOCK		BIT(1)
108 #define OWL_DMA_INTCTL_FRAME			BIT(2)
109 #define OWL_DMA_INTCTL_HALF_FRAME		BIT(3)
110 #define OWL_DMA_INTCTL_LAST_FRAME		BIT(4)
111 
112 /* OWL_DMAX_INT_STATUS Bits */
113 #define OWL_DMA_INTSTAT_BLOCK			BIT(0)
114 #define OWL_DMA_INTSTAT_SUPER_BLOCK		BIT(1)
115 #define OWL_DMA_INTSTAT_FRAME			BIT(2)
116 #define OWL_DMA_INTSTAT_HALF_FRAME		BIT(3)
117 #define OWL_DMA_INTSTAT_LAST_FRAME		BIT(4)
118 
119 /* Pack shift and newshift in a single word */
120 #define BIT_FIELD(val, width, shift, newshift)	\
121 		((((val) >> (shift)) & ((BIT(width)) - 1)) << (newshift))
122 
123 /**
124  * struct owl_dma_lli_hw - Hardware link list for dma transfer
125  * @next_lli: physical address of the next link list
126  * @saddr: source physical address
127  * @daddr: destination physical address
128  * @flen: frame length
129  * @fcnt: frame count
130  * @src_stride: source stride
131  * @dst_stride: destination stride
132  * @ctrla: dma_mode and linklist ctrl config
133  * @ctrlb: interrupt config
134  * @const_num: data for constant fill
135  */
136 struct owl_dma_lli_hw {
137 	u32	next_lli;
138 	u32	saddr;
139 	u32	daddr;
140 	u32	flen:20;
141 	u32	fcnt:12;
142 	u32	src_stride;
143 	u32	dst_stride;
144 	u32	ctrla;
145 	u32	ctrlb;
146 	u32	const_num;
147 };
148 
149 /**
150  * struct owl_dma_lli - Link list for dma transfer
151  * @hw: hardware link list
152  * @phys: physical address of hardware link list
153  * @node: node for txd's lli_list
154  */
155 struct owl_dma_lli {
156 	struct  owl_dma_lli_hw	hw;
157 	dma_addr_t		phys;
158 	struct list_head	node;
159 };
160 
161 /**
162  * struct owl_dma_txd - Wrapper for struct dma_async_tx_descriptor
163  * @vd: virtual DMA descriptor
164  * @lli_list: link list of lli nodes
165  * @cyclic: flag to indicate cyclic transfers
166  */
167 struct owl_dma_txd {
168 	struct virt_dma_desc	vd;
169 	struct list_head	lli_list;
170 	bool			cyclic;
171 };
172 
173 /**
174  * struct owl_dma_pchan - Holder for the physical channels
175  * @id: physical index to this channel
176  * @base: virtual memory base for the dma channel
177  * @vchan: the virtual channel currently being served by this physical channel
178  * @lock: a lock to use when altering an instance of this struct
179  */
180 struct owl_dma_pchan {
181 	u32			id;
182 	void __iomem		*base;
183 	struct owl_dma_vchan	*vchan;
184 	spinlock_t		lock;
185 };
186 
187 /**
188  * struct owl_dma_pchan - Wrapper for DMA ENGINE channel
189  * @vc: wrappped virtual channel
190  * @pchan: the physical channel utilized by this channel
191  * @txd: active transaction on this channel
192  * @cfg: slave configuration for this channel
193  * @drq: physical DMA request ID for this channel
194  */
195 struct owl_dma_vchan {
196 	struct virt_dma_chan	vc;
197 	struct owl_dma_pchan	*pchan;
198 	struct owl_dma_txd	*txd;
199 	struct dma_slave_config cfg;
200 	u8			drq;
201 };
202 
203 /**
204  * struct owl_dma - Holder for the Owl DMA controller
205  * @dma: dma engine for this instance
206  * @base: virtual memory base for the DMA controller
207  * @clk: clock for the DMA controller
208  * @lock: a lock to use when change DMA controller global register
209  * @lli_pool: a pool for the LLI descriptors
210  * @irq: interrupt ID for the DMA controller
211  * @nr_pchans: the number of physical channels
212  * @pchans: array of data for the physical channels
213  * @nr_vchans: the number of physical channels
214  * @vchans: array of data for the physical channels
215  */
216 struct owl_dma {
217 	struct dma_device	dma;
218 	void __iomem		*base;
219 	struct clk		*clk;
220 	spinlock_t		lock;
221 	struct dma_pool		*lli_pool;
222 	int			irq;
223 
224 	unsigned int		nr_pchans;
225 	struct owl_dma_pchan	*pchans;
226 
227 	unsigned int		nr_vchans;
228 	struct owl_dma_vchan	*vchans;
229 };
230 
231 static void pchan_update(struct owl_dma_pchan *pchan, u32 reg,
232 			 u32 val, bool state)
233 {
234 	u32 regval;
235 
236 	regval = readl(pchan->base + reg);
237 
238 	if (state)
239 		regval |= val;
240 	else
241 		regval &= ~val;
242 
243 	writel(val, pchan->base + reg);
244 }
245 
246 static void pchan_writel(struct owl_dma_pchan *pchan, u32 reg, u32 data)
247 {
248 	writel(data, pchan->base + reg);
249 }
250 
251 static u32 pchan_readl(struct owl_dma_pchan *pchan, u32 reg)
252 {
253 	return readl(pchan->base + reg);
254 }
255 
256 static void dma_update(struct owl_dma *od, u32 reg, u32 val, bool state)
257 {
258 	u32 regval;
259 
260 	regval = readl(od->base + reg);
261 
262 	if (state)
263 		regval |= val;
264 	else
265 		regval &= ~val;
266 
267 	writel(val, od->base + reg);
268 }
269 
270 static void dma_writel(struct owl_dma *od, u32 reg, u32 data)
271 {
272 	writel(data, od->base + reg);
273 }
274 
275 static u32 dma_readl(struct owl_dma *od, u32 reg)
276 {
277 	return readl(od->base + reg);
278 }
279 
280 static inline struct owl_dma *to_owl_dma(struct dma_device *dd)
281 {
282 	return container_of(dd, struct owl_dma, dma);
283 }
284 
285 static struct device *chan2dev(struct dma_chan *chan)
286 {
287 	return &chan->dev->device;
288 }
289 
290 static inline struct owl_dma_vchan *to_owl_vchan(struct dma_chan *chan)
291 {
292 	return container_of(chan, struct owl_dma_vchan, vc.chan);
293 }
294 
295 static inline struct owl_dma_txd *to_owl_txd(struct dma_async_tx_descriptor *tx)
296 {
297 	return container_of(tx, struct owl_dma_txd, vd.tx);
298 }
299 
300 static inline u32 llc_hw_ctrla(u32 mode, u32 llc_ctl)
301 {
302 	u32 ctl;
303 
304 	ctl = BIT_FIELD(mode, 4, 28, 28) |
305 	      BIT_FIELD(mode, 8, 16, 20) |
306 	      BIT_FIELD(mode, 4, 8, 16) |
307 	      BIT_FIELD(mode, 6, 0, 10) |
308 	      BIT_FIELD(llc_ctl, 2, 10, 8) |
309 	      BIT_FIELD(llc_ctl, 2, 8, 6);
310 
311 	return ctl;
312 }
313 
314 static inline u32 llc_hw_ctrlb(u32 int_ctl)
315 {
316 	u32 ctl;
317 
318 	ctl = BIT_FIELD(int_ctl, 7, 0, 18);
319 
320 	return ctl;
321 }
322 
323 static void owl_dma_free_lli(struct owl_dma *od,
324 			     struct owl_dma_lli *lli)
325 {
326 	list_del(&lli->node);
327 	dma_pool_free(od->lli_pool, lli, lli->phys);
328 }
329 
330 static struct owl_dma_lli *owl_dma_alloc_lli(struct owl_dma *od)
331 {
332 	struct owl_dma_lli *lli;
333 	dma_addr_t phys;
334 
335 	lli = dma_pool_alloc(od->lli_pool, GFP_NOWAIT, &phys);
336 	if (!lli)
337 		return NULL;
338 
339 	INIT_LIST_HEAD(&lli->node);
340 	lli->phys = phys;
341 
342 	return lli;
343 }
344 
345 static struct owl_dma_lli *owl_dma_add_lli(struct owl_dma_txd *txd,
346 					   struct owl_dma_lli *prev,
347 					   struct owl_dma_lli *next,
348 					   bool is_cyclic)
349 {
350 	if (!is_cyclic)
351 		list_add_tail(&next->node, &txd->lli_list);
352 
353 	if (prev) {
354 		prev->hw.next_lli = next->phys;
355 		prev->hw.ctrla |= llc_hw_ctrla(OWL_DMA_MODE_LME, 0);
356 	}
357 
358 	return next;
359 }
360 
361 static inline int owl_dma_cfg_lli(struct owl_dma_vchan *vchan,
362 				  struct owl_dma_lli *lli,
363 				  dma_addr_t src, dma_addr_t dst,
364 				  u32 len, enum dma_transfer_direction dir,
365 				  struct dma_slave_config *sconfig,
366 				  bool is_cyclic)
367 {
368 	struct owl_dma_lli_hw *hw = &lli->hw;
369 	u32 mode;
370 
371 	mode = OWL_DMA_MODE_PW(0);
372 
373 	switch (dir) {
374 	case DMA_MEM_TO_MEM:
375 		mode |= OWL_DMA_MODE_TS(0) | OWL_DMA_MODE_ST_DCU |
376 			OWL_DMA_MODE_DT_DCU | OWL_DMA_MODE_SAM_INC |
377 			OWL_DMA_MODE_DAM_INC;
378 
379 		break;
380 	case DMA_MEM_TO_DEV:
381 		mode |= OWL_DMA_MODE_TS(vchan->drq)
382 			| OWL_DMA_MODE_ST_DCU | OWL_DMA_MODE_DT_DEV
383 			| OWL_DMA_MODE_SAM_INC | OWL_DMA_MODE_DAM_CONST;
384 
385 		/*
386 		 * Hardware only supports 32bit and 8bit buswidth. Since the
387 		 * default is 32bit, select 8bit only when requested.
388 		 */
389 		if (sconfig->dst_addr_width == DMA_SLAVE_BUSWIDTH_1_BYTE)
390 			mode |= OWL_DMA_MODE_NDDBW_8BIT;
391 
392 		break;
393 	case DMA_DEV_TO_MEM:
394 		 mode |= OWL_DMA_MODE_TS(vchan->drq)
395 			| OWL_DMA_MODE_ST_DEV | OWL_DMA_MODE_DT_DCU
396 			| OWL_DMA_MODE_SAM_CONST | OWL_DMA_MODE_DAM_INC;
397 
398 		/*
399 		 * Hardware only supports 32bit and 8bit buswidth. Since the
400 		 * default is 32bit, select 8bit only when requested.
401 		 */
402 		if (sconfig->src_addr_width == DMA_SLAVE_BUSWIDTH_1_BYTE)
403 			mode |= OWL_DMA_MODE_NDDBW_8BIT;
404 
405 		break;
406 	default:
407 		return -EINVAL;
408 	}
409 
410 	hw->next_lli = 0; /* One link list by default */
411 	hw->saddr = src;
412 	hw->daddr = dst;
413 
414 	hw->fcnt = 1; /* Frame count fixed as 1 */
415 	hw->flen = len; /* Max frame length is 1MB */
416 	hw->src_stride = 0;
417 	hw->dst_stride = 0;
418 	hw->ctrla = llc_hw_ctrla(mode,
419 				 OWL_DMA_LLC_SAV_LOAD_NEXT |
420 				 OWL_DMA_LLC_DAV_LOAD_NEXT);
421 
422 	if (is_cyclic)
423 		hw->ctrlb = llc_hw_ctrlb(OWL_DMA_INTCTL_BLOCK);
424 	else
425 		hw->ctrlb = llc_hw_ctrlb(OWL_DMA_INTCTL_SUPER_BLOCK);
426 
427 	return 0;
428 }
429 
430 static struct owl_dma_pchan *owl_dma_get_pchan(struct owl_dma *od,
431 					       struct owl_dma_vchan *vchan)
432 {
433 	struct owl_dma_pchan *pchan = NULL;
434 	unsigned long flags;
435 	int i;
436 
437 	for (i = 0; i < od->nr_pchans; i++) {
438 		pchan = &od->pchans[i];
439 
440 		spin_lock_irqsave(&pchan->lock, flags);
441 		if (!pchan->vchan) {
442 			pchan->vchan = vchan;
443 			spin_unlock_irqrestore(&pchan->lock, flags);
444 			break;
445 		}
446 
447 		spin_unlock_irqrestore(&pchan->lock, flags);
448 	}
449 
450 	return pchan;
451 }
452 
453 static int owl_dma_pchan_busy(struct owl_dma *od, struct owl_dma_pchan *pchan)
454 {
455 	unsigned int val;
456 
457 	val = dma_readl(od, OWL_DMA_IDLE_STAT);
458 
459 	return !(val & (1 << pchan->id));
460 }
461 
462 static void owl_dma_terminate_pchan(struct owl_dma *od,
463 				    struct owl_dma_pchan *pchan)
464 {
465 	unsigned long flags;
466 	u32 irq_pd;
467 
468 	pchan_writel(pchan, OWL_DMAX_START, 0);
469 	pchan_update(pchan, OWL_DMAX_INT_STATUS, 0xff, false);
470 
471 	spin_lock_irqsave(&od->lock, flags);
472 	dma_update(od, OWL_DMA_IRQ_EN0, (1 << pchan->id), false);
473 
474 	irq_pd = dma_readl(od, OWL_DMA_IRQ_PD0);
475 	if (irq_pd & (1 << pchan->id)) {
476 		dev_warn(od->dma.dev,
477 			 "terminating pchan %d that still has pending irq\n",
478 			 pchan->id);
479 		dma_writel(od, OWL_DMA_IRQ_PD0, (1 << pchan->id));
480 	}
481 
482 	pchan->vchan = NULL;
483 
484 	spin_unlock_irqrestore(&od->lock, flags);
485 }
486 
487 static void owl_dma_pause_pchan(struct owl_dma_pchan *pchan)
488 {
489 	pchan_writel(pchan, 1, OWL_DMAX_PAUSE);
490 }
491 
492 static void owl_dma_resume_pchan(struct owl_dma_pchan *pchan)
493 {
494 	pchan_writel(pchan, 0, OWL_DMAX_PAUSE);
495 }
496 
497 static int owl_dma_start_next_txd(struct owl_dma_vchan *vchan)
498 {
499 	struct owl_dma *od = to_owl_dma(vchan->vc.chan.device);
500 	struct virt_dma_desc *vd = vchan_next_desc(&vchan->vc);
501 	struct owl_dma_pchan *pchan = vchan->pchan;
502 	struct owl_dma_txd *txd = to_owl_txd(&vd->tx);
503 	struct owl_dma_lli *lli;
504 	unsigned long flags;
505 	u32 int_ctl;
506 
507 	list_del(&vd->node);
508 
509 	vchan->txd = txd;
510 
511 	/* Wait for channel inactive */
512 	while (owl_dma_pchan_busy(od, pchan))
513 		cpu_relax();
514 
515 	lli = list_first_entry(&txd->lli_list,
516 			       struct owl_dma_lli, node);
517 
518 	if (txd->cyclic)
519 		int_ctl = OWL_DMA_INTCTL_BLOCK;
520 	else
521 		int_ctl = OWL_DMA_INTCTL_SUPER_BLOCK;
522 
523 	pchan_writel(pchan, OWL_DMAX_MODE, OWL_DMA_MODE_LME);
524 	pchan_writel(pchan, OWL_DMAX_LINKLIST_CTL,
525 		     OWL_DMA_LLC_SAV_LOAD_NEXT | OWL_DMA_LLC_DAV_LOAD_NEXT);
526 	pchan_writel(pchan, OWL_DMAX_NEXT_DESCRIPTOR, lli->phys);
527 	pchan_writel(pchan, OWL_DMAX_INT_CTL, int_ctl);
528 
529 	/* Clear IRQ status for this pchan */
530 	pchan_update(pchan, OWL_DMAX_INT_STATUS, 0xff, false);
531 
532 	spin_lock_irqsave(&od->lock, flags);
533 
534 	dma_update(od, OWL_DMA_IRQ_EN0, (1 << pchan->id), true);
535 
536 	spin_unlock_irqrestore(&od->lock, flags);
537 
538 	dev_dbg(chan2dev(&vchan->vc.chan), "starting pchan %d\n", pchan->id);
539 
540 	/* Start DMA transfer for this pchan */
541 	pchan_writel(pchan, OWL_DMAX_START, 0x1);
542 
543 	return 0;
544 }
545 
546 static void owl_dma_phy_free(struct owl_dma *od, struct owl_dma_vchan *vchan)
547 {
548 	/* Ensure that the physical channel is stopped */
549 	owl_dma_terminate_pchan(od, vchan->pchan);
550 
551 	vchan->pchan = NULL;
552 }
553 
554 static irqreturn_t owl_dma_interrupt(int irq, void *dev_id)
555 {
556 	struct owl_dma *od = dev_id;
557 	struct owl_dma_vchan *vchan;
558 	struct owl_dma_pchan *pchan;
559 	unsigned long pending;
560 	int i;
561 	unsigned int global_irq_pending, chan_irq_pending;
562 
563 	spin_lock(&od->lock);
564 
565 	pending = dma_readl(od, OWL_DMA_IRQ_PD0);
566 
567 	/* Clear IRQ status for each pchan */
568 	for_each_set_bit(i, &pending, od->nr_pchans) {
569 		pchan = &od->pchans[i];
570 		pchan_update(pchan, OWL_DMAX_INT_STATUS, 0xff, false);
571 	}
572 
573 	/* Clear pending IRQ */
574 	dma_writel(od, OWL_DMA_IRQ_PD0, pending);
575 
576 	/* Check missed pending IRQ */
577 	for (i = 0; i < od->nr_pchans; i++) {
578 		pchan = &od->pchans[i];
579 		chan_irq_pending = pchan_readl(pchan, OWL_DMAX_INT_CTL) &
580 				   pchan_readl(pchan, OWL_DMAX_INT_STATUS);
581 
582 		/* Dummy read to ensure OWL_DMA_IRQ_PD0 value is updated */
583 		dma_readl(od, OWL_DMA_IRQ_PD0);
584 
585 		global_irq_pending = dma_readl(od, OWL_DMA_IRQ_PD0);
586 
587 		if (chan_irq_pending && !(global_irq_pending & BIT(i)))	{
588 			dev_dbg(od->dma.dev,
589 				"global and channel IRQ pending match err\n");
590 
591 			/* Clear IRQ status for this pchan */
592 			pchan_update(pchan, OWL_DMAX_INT_STATUS,
593 				     0xff, false);
594 
595 			/* Update global IRQ pending */
596 			pending |= BIT(i);
597 		}
598 	}
599 
600 	spin_unlock(&od->lock);
601 
602 	for_each_set_bit(i, &pending, od->nr_pchans) {
603 		struct owl_dma_txd *txd;
604 
605 		pchan = &od->pchans[i];
606 
607 		vchan = pchan->vchan;
608 		if (!vchan) {
609 			dev_warn(od->dma.dev, "no vchan attached on pchan %d\n",
610 				 pchan->id);
611 			continue;
612 		}
613 
614 		spin_lock(&vchan->vc.lock);
615 
616 		txd = vchan->txd;
617 		if (txd) {
618 			vchan->txd = NULL;
619 
620 			vchan_cookie_complete(&txd->vd);
621 
622 			/*
623 			 * Start the next descriptor (if any),
624 			 * otherwise free this channel.
625 			 */
626 			if (vchan_next_desc(&vchan->vc))
627 				owl_dma_start_next_txd(vchan);
628 			else
629 				owl_dma_phy_free(od, vchan);
630 		}
631 
632 		spin_unlock(&vchan->vc.lock);
633 	}
634 
635 	return IRQ_HANDLED;
636 }
637 
638 static void owl_dma_free_txd(struct owl_dma *od, struct owl_dma_txd *txd)
639 {
640 	struct owl_dma_lli *lli, *_lli;
641 
642 	if (unlikely(!txd))
643 		return;
644 
645 	list_for_each_entry_safe(lli, _lli, &txd->lli_list, node)
646 		owl_dma_free_lli(od, lli);
647 
648 	kfree(txd);
649 }
650 
651 static void owl_dma_desc_free(struct virt_dma_desc *vd)
652 {
653 	struct owl_dma *od = to_owl_dma(vd->tx.chan->device);
654 	struct owl_dma_txd *txd = to_owl_txd(&vd->tx);
655 
656 	owl_dma_free_txd(od, txd);
657 }
658 
659 static int owl_dma_terminate_all(struct dma_chan *chan)
660 {
661 	struct owl_dma *od = to_owl_dma(chan->device);
662 	struct owl_dma_vchan *vchan = to_owl_vchan(chan);
663 	unsigned long flags;
664 	LIST_HEAD(head);
665 
666 	spin_lock_irqsave(&vchan->vc.lock, flags);
667 
668 	if (vchan->pchan)
669 		owl_dma_phy_free(od, vchan);
670 
671 	if (vchan->txd) {
672 		owl_dma_desc_free(&vchan->txd->vd);
673 		vchan->txd = NULL;
674 	}
675 
676 	vchan_get_all_descriptors(&vchan->vc, &head);
677 	vchan_dma_desc_free_list(&vchan->vc, &head);
678 
679 	spin_unlock_irqrestore(&vchan->vc.lock, flags);
680 
681 	return 0;
682 }
683 
684 static int owl_dma_config(struct dma_chan *chan,
685 			  struct dma_slave_config *config)
686 {
687 	struct owl_dma_vchan *vchan = to_owl_vchan(chan);
688 
689 	/* Reject definitely invalid configurations */
690 	if (config->src_addr_width == DMA_SLAVE_BUSWIDTH_8_BYTES ||
691 	    config->dst_addr_width == DMA_SLAVE_BUSWIDTH_8_BYTES)
692 		return -EINVAL;
693 
694 	memcpy(&vchan->cfg, config, sizeof(struct dma_slave_config));
695 
696 	return 0;
697 }
698 
699 static int owl_dma_pause(struct dma_chan *chan)
700 {
701 	struct owl_dma_vchan *vchan = to_owl_vchan(chan);
702 	unsigned long flags;
703 
704 	spin_lock_irqsave(&vchan->vc.lock, flags);
705 
706 	owl_dma_pause_pchan(vchan->pchan);
707 
708 	spin_unlock_irqrestore(&vchan->vc.lock, flags);
709 
710 	return 0;
711 }
712 
713 static int owl_dma_resume(struct dma_chan *chan)
714 {
715 	struct owl_dma_vchan *vchan = to_owl_vchan(chan);
716 	unsigned long flags;
717 
718 	if (!vchan->pchan && !vchan->txd)
719 		return 0;
720 
721 	dev_dbg(chan2dev(chan), "vchan %p: resume\n", &vchan->vc);
722 
723 	spin_lock_irqsave(&vchan->vc.lock, flags);
724 
725 	owl_dma_resume_pchan(vchan->pchan);
726 
727 	spin_unlock_irqrestore(&vchan->vc.lock, flags);
728 
729 	return 0;
730 }
731 
732 static u32 owl_dma_getbytes_chan(struct owl_dma_vchan *vchan)
733 {
734 	struct owl_dma_pchan *pchan;
735 	struct owl_dma_txd *txd;
736 	struct owl_dma_lli *lli;
737 	unsigned int next_lli_phy;
738 	size_t bytes;
739 
740 	pchan = vchan->pchan;
741 	txd = vchan->txd;
742 
743 	if (!pchan || !txd)
744 		return 0;
745 
746 	/* Get remain count of current node in link list */
747 	bytes = pchan_readl(pchan, OWL_DMAX_REMAIN_CNT);
748 
749 	/* Loop through the preceding nodes to get total remaining bytes */
750 	if (pchan_readl(pchan, OWL_DMAX_MODE) & OWL_DMA_MODE_LME) {
751 		next_lli_phy = pchan_readl(pchan, OWL_DMAX_NEXT_DESCRIPTOR);
752 		list_for_each_entry(lli, &txd->lli_list, node) {
753 			/* Start from the next active node */
754 			if (lli->phys == next_lli_phy) {
755 				list_for_each_entry(lli, &txd->lli_list, node)
756 					bytes += lli->hw.flen;
757 				break;
758 			}
759 		}
760 	}
761 
762 	return bytes;
763 }
764 
765 static enum dma_status owl_dma_tx_status(struct dma_chan *chan,
766 					 dma_cookie_t cookie,
767 					 struct dma_tx_state *state)
768 {
769 	struct owl_dma_vchan *vchan = to_owl_vchan(chan);
770 	struct owl_dma_lli *lli;
771 	struct virt_dma_desc *vd;
772 	struct owl_dma_txd *txd;
773 	enum dma_status ret;
774 	unsigned long flags;
775 	size_t bytes = 0;
776 
777 	ret = dma_cookie_status(chan, cookie, state);
778 	if (ret == DMA_COMPLETE || !state)
779 		return ret;
780 
781 	spin_lock_irqsave(&vchan->vc.lock, flags);
782 
783 	vd = vchan_find_desc(&vchan->vc, cookie);
784 	if (vd) {
785 		txd = to_owl_txd(&vd->tx);
786 		list_for_each_entry(lli, &txd->lli_list, node)
787 			bytes += lli->hw.flen;
788 	} else {
789 		bytes = owl_dma_getbytes_chan(vchan);
790 	}
791 
792 	spin_unlock_irqrestore(&vchan->vc.lock, flags);
793 
794 	dma_set_residue(state, bytes);
795 
796 	return ret;
797 }
798 
799 static void owl_dma_phy_alloc_and_start(struct owl_dma_vchan *vchan)
800 {
801 	struct owl_dma *od = to_owl_dma(vchan->vc.chan.device);
802 	struct owl_dma_pchan *pchan;
803 
804 	pchan = owl_dma_get_pchan(od, vchan);
805 	if (!pchan)
806 		return;
807 
808 	dev_dbg(od->dma.dev, "allocated pchan %d\n", pchan->id);
809 
810 	vchan->pchan = pchan;
811 	owl_dma_start_next_txd(vchan);
812 }
813 
814 static void owl_dma_issue_pending(struct dma_chan *chan)
815 {
816 	struct owl_dma_vchan *vchan = to_owl_vchan(chan);
817 	unsigned long flags;
818 
819 	spin_lock_irqsave(&vchan->vc.lock, flags);
820 	if (vchan_issue_pending(&vchan->vc)) {
821 		if (!vchan->pchan)
822 			owl_dma_phy_alloc_and_start(vchan);
823 	}
824 	spin_unlock_irqrestore(&vchan->vc.lock, flags);
825 }
826 
827 static struct dma_async_tx_descriptor
828 		*owl_dma_prep_memcpy(struct dma_chan *chan,
829 				     dma_addr_t dst, dma_addr_t src,
830 				     size_t len, unsigned long flags)
831 {
832 	struct owl_dma *od = to_owl_dma(chan->device);
833 	struct owl_dma_vchan *vchan = to_owl_vchan(chan);
834 	struct owl_dma_txd *txd;
835 	struct owl_dma_lli *lli, *prev = NULL;
836 	size_t offset, bytes;
837 	int ret;
838 
839 	if (!len)
840 		return NULL;
841 
842 	txd = kzalloc(sizeof(*txd), GFP_NOWAIT);
843 	if (!txd)
844 		return NULL;
845 
846 	INIT_LIST_HEAD(&txd->lli_list);
847 
848 	/* Process the transfer as frame by frame */
849 	for (offset = 0; offset < len; offset += bytes) {
850 		lli = owl_dma_alloc_lli(od);
851 		if (!lli) {
852 			dev_warn(chan2dev(chan), "failed to allocate lli\n");
853 			goto err_txd_free;
854 		}
855 
856 		bytes = min_t(size_t, (len - offset), OWL_DMA_FRAME_MAX_LENGTH);
857 
858 		ret = owl_dma_cfg_lli(vchan, lli, src + offset, dst + offset,
859 				      bytes, DMA_MEM_TO_MEM,
860 				      &vchan->cfg, txd->cyclic);
861 		if (ret) {
862 			dev_warn(chan2dev(chan), "failed to config lli\n");
863 			goto err_txd_free;
864 		}
865 
866 		prev = owl_dma_add_lli(txd, prev, lli, false);
867 	}
868 
869 	return vchan_tx_prep(&vchan->vc, &txd->vd, flags);
870 
871 err_txd_free:
872 	owl_dma_free_txd(od, txd);
873 	return NULL;
874 }
875 
876 static struct dma_async_tx_descriptor
877 		*owl_dma_prep_slave_sg(struct dma_chan *chan,
878 				       struct scatterlist *sgl,
879 				       unsigned int sg_len,
880 				       enum dma_transfer_direction dir,
881 				       unsigned long flags, void *context)
882 {
883 	struct owl_dma *od = to_owl_dma(chan->device);
884 	struct owl_dma_vchan *vchan = to_owl_vchan(chan);
885 	struct dma_slave_config *sconfig = &vchan->cfg;
886 	struct owl_dma_txd *txd;
887 	struct owl_dma_lli *lli, *prev = NULL;
888 	struct scatterlist *sg;
889 	dma_addr_t addr, src = 0, dst = 0;
890 	size_t len;
891 	int ret, i;
892 
893 	txd = kzalloc(sizeof(*txd), GFP_NOWAIT);
894 	if (!txd)
895 		return NULL;
896 
897 	INIT_LIST_HEAD(&txd->lli_list);
898 
899 	for_each_sg(sgl, sg, sg_len, i) {
900 		addr = sg_dma_address(sg);
901 		len = sg_dma_len(sg);
902 
903 		if (len > OWL_DMA_FRAME_MAX_LENGTH) {
904 			dev_err(od->dma.dev,
905 				"frame length exceeds max supported length");
906 			goto err_txd_free;
907 		}
908 
909 		lli = owl_dma_alloc_lli(od);
910 		if (!lli) {
911 			dev_err(chan2dev(chan), "failed to allocate lli");
912 			goto err_txd_free;
913 		}
914 
915 		if (dir == DMA_MEM_TO_DEV) {
916 			src = addr;
917 			dst = sconfig->dst_addr;
918 		} else {
919 			src = sconfig->src_addr;
920 			dst = addr;
921 		}
922 
923 		ret = owl_dma_cfg_lli(vchan, lli, src, dst, len, dir, sconfig,
924 				      txd->cyclic);
925 		if (ret) {
926 			dev_warn(chan2dev(chan), "failed to config lli");
927 			goto err_txd_free;
928 		}
929 
930 		prev = owl_dma_add_lli(txd, prev, lli, false);
931 	}
932 
933 	return vchan_tx_prep(&vchan->vc, &txd->vd, flags);
934 
935 err_txd_free:
936 	owl_dma_free_txd(od, txd);
937 
938 	return NULL;
939 }
940 
941 static struct dma_async_tx_descriptor
942 		*owl_prep_dma_cyclic(struct dma_chan *chan,
943 				     dma_addr_t buf_addr, size_t buf_len,
944 				     size_t period_len,
945 				     enum dma_transfer_direction dir,
946 				     unsigned long flags)
947 {
948 	struct owl_dma *od = to_owl_dma(chan->device);
949 	struct owl_dma_vchan *vchan = to_owl_vchan(chan);
950 	struct dma_slave_config *sconfig = &vchan->cfg;
951 	struct owl_dma_txd *txd;
952 	struct owl_dma_lli *lli, *prev = NULL, *first = NULL;
953 	dma_addr_t src = 0, dst = 0;
954 	unsigned int periods = buf_len / period_len;
955 	int ret, i;
956 
957 	txd = kzalloc(sizeof(*txd), GFP_NOWAIT);
958 	if (!txd)
959 		return NULL;
960 
961 	INIT_LIST_HEAD(&txd->lli_list);
962 	txd->cyclic = true;
963 
964 	for (i = 0; i < periods; i++) {
965 		lli = owl_dma_alloc_lli(od);
966 		if (!lli) {
967 			dev_warn(chan2dev(chan), "failed to allocate lli");
968 			goto err_txd_free;
969 		}
970 
971 		if (dir == DMA_MEM_TO_DEV) {
972 			src = buf_addr + (period_len * i);
973 			dst = sconfig->dst_addr;
974 		} else if (dir == DMA_DEV_TO_MEM) {
975 			src = sconfig->src_addr;
976 			dst = buf_addr + (period_len * i);
977 		}
978 
979 		ret = owl_dma_cfg_lli(vchan, lli, src, dst, period_len,
980 				      dir, sconfig, txd->cyclic);
981 		if (ret) {
982 			dev_warn(chan2dev(chan), "failed to config lli");
983 			goto err_txd_free;
984 		}
985 
986 		if (!first)
987 			first = lli;
988 
989 		prev = owl_dma_add_lli(txd, prev, lli, false);
990 	}
991 
992 	/* close the cyclic list */
993 	owl_dma_add_lli(txd, prev, first, true);
994 
995 	return vchan_tx_prep(&vchan->vc, &txd->vd, flags);
996 
997 err_txd_free:
998 	owl_dma_free_txd(od, txd);
999 
1000 	return NULL;
1001 }
1002 
1003 static void owl_dma_free_chan_resources(struct dma_chan *chan)
1004 {
1005 	struct owl_dma_vchan *vchan = to_owl_vchan(chan);
1006 
1007 	/* Ensure all queued descriptors are freed */
1008 	vchan_free_chan_resources(&vchan->vc);
1009 }
1010 
1011 static inline void owl_dma_free(struct owl_dma *od)
1012 {
1013 	struct owl_dma_vchan *vchan = NULL;
1014 	struct owl_dma_vchan *next;
1015 
1016 	list_for_each_entry_safe(vchan,
1017 				 next, &od->dma.channels, vc.chan.device_node) {
1018 		list_del(&vchan->vc.chan.device_node);
1019 		tasklet_kill(&vchan->vc.task);
1020 	}
1021 }
1022 
1023 static struct dma_chan *owl_dma_of_xlate(struct of_phandle_args *dma_spec,
1024 					 struct of_dma *ofdma)
1025 {
1026 	struct owl_dma *od = ofdma->of_dma_data;
1027 	struct owl_dma_vchan *vchan;
1028 	struct dma_chan *chan;
1029 	u8 drq = dma_spec->args[0];
1030 
1031 	if (drq > od->nr_vchans)
1032 		return NULL;
1033 
1034 	chan = dma_get_any_slave_channel(&od->dma);
1035 	if (!chan)
1036 		return NULL;
1037 
1038 	vchan = to_owl_vchan(chan);
1039 	vchan->drq = drq;
1040 
1041 	return chan;
1042 }
1043 
1044 static int owl_dma_probe(struct platform_device *pdev)
1045 {
1046 	struct device_node *np = pdev->dev.of_node;
1047 	struct owl_dma *od;
1048 	int ret, i, nr_channels, nr_requests;
1049 
1050 	od = devm_kzalloc(&pdev->dev, sizeof(*od), GFP_KERNEL);
1051 	if (!od)
1052 		return -ENOMEM;
1053 
1054 	od->base = devm_platform_ioremap_resource(pdev, 0);
1055 	if (IS_ERR(od->base))
1056 		return PTR_ERR(od->base);
1057 
1058 	ret = of_property_read_u32(np, "dma-channels", &nr_channels);
1059 	if (ret) {
1060 		dev_err(&pdev->dev, "can't get dma-channels\n");
1061 		return ret;
1062 	}
1063 
1064 	ret = of_property_read_u32(np, "dma-requests", &nr_requests);
1065 	if (ret) {
1066 		dev_err(&pdev->dev, "can't get dma-requests\n");
1067 		return ret;
1068 	}
1069 
1070 	dev_info(&pdev->dev, "dma-channels %d, dma-requests %d\n",
1071 		 nr_channels, nr_requests);
1072 
1073 	od->nr_pchans = nr_channels;
1074 	od->nr_vchans = nr_requests;
1075 
1076 	pdev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
1077 
1078 	platform_set_drvdata(pdev, od);
1079 	spin_lock_init(&od->lock);
1080 
1081 	dma_cap_set(DMA_MEMCPY, od->dma.cap_mask);
1082 	dma_cap_set(DMA_SLAVE, od->dma.cap_mask);
1083 	dma_cap_set(DMA_CYCLIC, od->dma.cap_mask);
1084 
1085 	od->dma.dev = &pdev->dev;
1086 	od->dma.device_free_chan_resources = owl_dma_free_chan_resources;
1087 	od->dma.device_tx_status = owl_dma_tx_status;
1088 	od->dma.device_issue_pending = owl_dma_issue_pending;
1089 	od->dma.device_prep_dma_memcpy = owl_dma_prep_memcpy;
1090 	od->dma.device_prep_slave_sg = owl_dma_prep_slave_sg;
1091 	od->dma.device_prep_dma_cyclic = owl_prep_dma_cyclic;
1092 	od->dma.device_config = owl_dma_config;
1093 	od->dma.device_pause = owl_dma_pause;
1094 	od->dma.device_resume = owl_dma_resume;
1095 	od->dma.device_terminate_all = owl_dma_terminate_all;
1096 	od->dma.src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
1097 	od->dma.dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
1098 	od->dma.directions = BIT(DMA_MEM_TO_MEM);
1099 	od->dma.residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
1100 
1101 	INIT_LIST_HEAD(&od->dma.channels);
1102 
1103 	od->clk = devm_clk_get(&pdev->dev, NULL);
1104 	if (IS_ERR(od->clk)) {
1105 		dev_err(&pdev->dev, "unable to get clock\n");
1106 		return PTR_ERR(od->clk);
1107 	}
1108 
1109 	/*
1110 	 * Eventhough the DMA controller is capable of generating 4
1111 	 * IRQ's for DMA priority feature, we only use 1 IRQ for
1112 	 * simplification.
1113 	 */
1114 	od->irq = platform_get_irq(pdev, 0);
1115 	ret = devm_request_irq(&pdev->dev, od->irq, owl_dma_interrupt, 0,
1116 			       dev_name(&pdev->dev), od);
1117 	if (ret) {
1118 		dev_err(&pdev->dev, "unable to request IRQ\n");
1119 		return ret;
1120 	}
1121 
1122 	/* Init physical channel */
1123 	od->pchans = devm_kcalloc(&pdev->dev, od->nr_pchans,
1124 				  sizeof(struct owl_dma_pchan), GFP_KERNEL);
1125 	if (!od->pchans)
1126 		return -ENOMEM;
1127 
1128 	for (i = 0; i < od->nr_pchans; i++) {
1129 		struct owl_dma_pchan *pchan = &od->pchans[i];
1130 
1131 		pchan->id = i;
1132 		pchan->base = od->base + OWL_DMA_CHAN_BASE(i);
1133 	}
1134 
1135 	/* Init virtual channel */
1136 	od->vchans = devm_kcalloc(&pdev->dev, od->nr_vchans,
1137 				  sizeof(struct owl_dma_vchan), GFP_KERNEL);
1138 	if (!od->vchans)
1139 		return -ENOMEM;
1140 
1141 	for (i = 0; i < od->nr_vchans; i++) {
1142 		struct owl_dma_vchan *vchan = &od->vchans[i];
1143 
1144 		vchan->vc.desc_free = owl_dma_desc_free;
1145 		vchan_init(&vchan->vc, &od->dma);
1146 	}
1147 
1148 	/* Create a pool of consistent memory blocks for hardware descriptors */
1149 	od->lli_pool = dma_pool_create(dev_name(od->dma.dev), od->dma.dev,
1150 				       sizeof(struct owl_dma_lli),
1151 				       __alignof__(struct owl_dma_lli),
1152 				       0);
1153 	if (!od->lli_pool) {
1154 		dev_err(&pdev->dev, "unable to allocate DMA descriptor pool\n");
1155 		return -ENOMEM;
1156 	}
1157 
1158 	clk_prepare_enable(od->clk);
1159 
1160 	ret = dma_async_device_register(&od->dma);
1161 	if (ret) {
1162 		dev_err(&pdev->dev, "failed to register DMA engine device\n");
1163 		goto err_pool_free;
1164 	}
1165 
1166 	/* Device-tree DMA controller registration */
1167 	ret = of_dma_controller_register(pdev->dev.of_node,
1168 					 owl_dma_of_xlate, od);
1169 	if (ret) {
1170 		dev_err(&pdev->dev, "of_dma_controller_register failed\n");
1171 		goto err_dma_unregister;
1172 	}
1173 
1174 	return 0;
1175 
1176 err_dma_unregister:
1177 	dma_async_device_unregister(&od->dma);
1178 err_pool_free:
1179 	clk_disable_unprepare(od->clk);
1180 	dma_pool_destroy(od->lli_pool);
1181 
1182 	return ret;
1183 }
1184 
1185 static int owl_dma_remove(struct platform_device *pdev)
1186 {
1187 	struct owl_dma *od = platform_get_drvdata(pdev);
1188 
1189 	of_dma_controller_free(pdev->dev.of_node);
1190 	dma_async_device_unregister(&od->dma);
1191 
1192 	/* Mask all interrupts for this execution environment */
1193 	dma_writel(od, OWL_DMA_IRQ_EN0, 0x0);
1194 
1195 	/* Make sure we won't have any further interrupts */
1196 	devm_free_irq(od->dma.dev, od->irq, od);
1197 
1198 	owl_dma_free(od);
1199 
1200 	clk_disable_unprepare(od->clk);
1201 
1202 	return 0;
1203 }
1204 
1205 static const struct of_device_id owl_dma_match[] = {
1206 	{ .compatible = "actions,s900-dma", },
1207 	{ /* sentinel */ }
1208 };
1209 MODULE_DEVICE_TABLE(of, owl_dma_match);
1210 
1211 static struct platform_driver owl_dma_driver = {
1212 	.probe	= owl_dma_probe,
1213 	.remove	= owl_dma_remove,
1214 	.driver = {
1215 		.name = "dma-owl",
1216 		.of_match_table = of_match_ptr(owl_dma_match),
1217 	},
1218 };
1219 
1220 static int owl_dma_init(void)
1221 {
1222 	return platform_driver_register(&owl_dma_driver);
1223 }
1224 subsys_initcall(owl_dma_init);
1225 
1226 static void __exit owl_dma_exit(void)
1227 {
1228 	platform_driver_unregister(&owl_dma_driver);
1229 }
1230 module_exit(owl_dma_exit);
1231 
1232 MODULE_AUTHOR("David Liu <liuwei@actions-semi.com>");
1233 MODULE_AUTHOR("Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>");
1234 MODULE_DESCRIPTION("Actions Semi Owl SoCs DMA driver");
1235 MODULE_LICENSE("GPL");
1236