xref: /openbmc/linux/drivers/dma/owl-dma.c (revision 8e2a46a4)
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  */
179 struct owl_dma_pchan {
180 	u32			id;
181 	void __iomem		*base;
182 	struct owl_dma_vchan	*vchan;
183 };
184 
185 /**
186  * struct owl_dma_pchan - Wrapper for DMA ENGINE channel
187  * @vc: wrappped virtual channel
188  * @pchan: the physical channel utilized by this channel
189  * @txd: active transaction on this channel
190  * @cfg: slave configuration for this channel
191  * @drq: physical DMA request ID for this channel
192  */
193 struct owl_dma_vchan {
194 	struct virt_dma_chan	vc;
195 	struct owl_dma_pchan	*pchan;
196 	struct owl_dma_txd	*txd;
197 	struct dma_slave_config cfg;
198 	u8			drq;
199 };
200 
201 /**
202  * struct owl_dma - Holder for the Owl DMA controller
203  * @dma: dma engine for this instance
204  * @base: virtual memory base for the DMA controller
205  * @clk: clock for the DMA controller
206  * @lock: a lock to use when change DMA controller global register
207  * @lli_pool: a pool for the LLI descriptors
208  * @irq: interrupt ID for the DMA controller
209  * @nr_pchans: the number of physical channels
210  * @pchans: array of data for the physical channels
211  * @nr_vchans: the number of physical channels
212  * @vchans: array of data for the physical channels
213  */
214 struct owl_dma {
215 	struct dma_device	dma;
216 	void __iomem		*base;
217 	struct clk		*clk;
218 	spinlock_t		lock;
219 	struct dma_pool		*lli_pool;
220 	int			irq;
221 
222 	unsigned int		nr_pchans;
223 	struct owl_dma_pchan	*pchans;
224 
225 	unsigned int		nr_vchans;
226 	struct owl_dma_vchan	*vchans;
227 };
228 
229 static void pchan_update(struct owl_dma_pchan *pchan, u32 reg,
230 			 u32 val, bool state)
231 {
232 	u32 regval;
233 
234 	regval = readl(pchan->base + reg);
235 
236 	if (state)
237 		regval |= val;
238 	else
239 		regval &= ~val;
240 
241 	writel(val, pchan->base + reg);
242 }
243 
244 static void pchan_writel(struct owl_dma_pchan *pchan, u32 reg, u32 data)
245 {
246 	writel(data, pchan->base + reg);
247 }
248 
249 static u32 pchan_readl(struct owl_dma_pchan *pchan, u32 reg)
250 {
251 	return readl(pchan->base + reg);
252 }
253 
254 static void dma_update(struct owl_dma *od, u32 reg, u32 val, bool state)
255 {
256 	u32 regval;
257 
258 	regval = readl(od->base + reg);
259 
260 	if (state)
261 		regval |= val;
262 	else
263 		regval &= ~val;
264 
265 	writel(val, od->base + reg);
266 }
267 
268 static void dma_writel(struct owl_dma *od, u32 reg, u32 data)
269 {
270 	writel(data, od->base + reg);
271 }
272 
273 static u32 dma_readl(struct owl_dma *od, u32 reg)
274 {
275 	return readl(od->base + reg);
276 }
277 
278 static inline struct owl_dma *to_owl_dma(struct dma_device *dd)
279 {
280 	return container_of(dd, struct owl_dma, dma);
281 }
282 
283 static struct device *chan2dev(struct dma_chan *chan)
284 {
285 	return &chan->dev->device;
286 }
287 
288 static inline struct owl_dma_vchan *to_owl_vchan(struct dma_chan *chan)
289 {
290 	return container_of(chan, struct owl_dma_vchan, vc.chan);
291 }
292 
293 static inline struct owl_dma_txd *to_owl_txd(struct dma_async_tx_descriptor *tx)
294 {
295 	return container_of(tx, struct owl_dma_txd, vd.tx);
296 }
297 
298 static inline u32 llc_hw_ctrla(u32 mode, u32 llc_ctl)
299 {
300 	u32 ctl;
301 
302 	ctl = BIT_FIELD(mode, 4, 28, 28) |
303 	      BIT_FIELD(mode, 8, 16, 20) |
304 	      BIT_FIELD(mode, 4, 8, 16) |
305 	      BIT_FIELD(mode, 6, 0, 10) |
306 	      BIT_FIELD(llc_ctl, 2, 10, 8) |
307 	      BIT_FIELD(llc_ctl, 2, 8, 6);
308 
309 	return ctl;
310 }
311 
312 static inline u32 llc_hw_ctrlb(u32 int_ctl)
313 {
314 	u32 ctl;
315 
316 	ctl = BIT_FIELD(int_ctl, 7, 0, 18);
317 
318 	return ctl;
319 }
320 
321 static void owl_dma_free_lli(struct owl_dma *od,
322 			     struct owl_dma_lli *lli)
323 {
324 	list_del(&lli->node);
325 	dma_pool_free(od->lli_pool, lli, lli->phys);
326 }
327 
328 static struct owl_dma_lli *owl_dma_alloc_lli(struct owl_dma *od)
329 {
330 	struct owl_dma_lli *lli;
331 	dma_addr_t phys;
332 
333 	lli = dma_pool_alloc(od->lli_pool, GFP_NOWAIT, &phys);
334 	if (!lli)
335 		return NULL;
336 
337 	INIT_LIST_HEAD(&lli->node);
338 	lli->phys = phys;
339 
340 	return lli;
341 }
342 
343 static struct owl_dma_lli *owl_dma_add_lli(struct owl_dma_txd *txd,
344 					   struct owl_dma_lli *prev,
345 					   struct owl_dma_lli *next,
346 					   bool is_cyclic)
347 {
348 	if (!is_cyclic)
349 		list_add_tail(&next->node, &txd->lli_list);
350 
351 	if (prev) {
352 		prev->hw.next_lli = next->phys;
353 		prev->hw.ctrla |= llc_hw_ctrla(OWL_DMA_MODE_LME, 0);
354 	}
355 
356 	return next;
357 }
358 
359 static inline int owl_dma_cfg_lli(struct owl_dma_vchan *vchan,
360 				  struct owl_dma_lli *lli,
361 				  dma_addr_t src, dma_addr_t dst,
362 				  u32 len, enum dma_transfer_direction dir,
363 				  struct dma_slave_config *sconfig,
364 				  bool is_cyclic)
365 {
366 	struct owl_dma_lli_hw *hw = &lli->hw;
367 	u32 mode;
368 
369 	mode = OWL_DMA_MODE_PW(0);
370 
371 	switch (dir) {
372 	case DMA_MEM_TO_MEM:
373 		mode |= OWL_DMA_MODE_TS(0) | OWL_DMA_MODE_ST_DCU |
374 			OWL_DMA_MODE_DT_DCU | OWL_DMA_MODE_SAM_INC |
375 			OWL_DMA_MODE_DAM_INC;
376 
377 		break;
378 	case DMA_MEM_TO_DEV:
379 		mode |= OWL_DMA_MODE_TS(vchan->drq)
380 			| OWL_DMA_MODE_ST_DCU | OWL_DMA_MODE_DT_DEV
381 			| OWL_DMA_MODE_SAM_INC | OWL_DMA_MODE_DAM_CONST;
382 
383 		/*
384 		 * Hardware only supports 32bit and 8bit buswidth. Since the
385 		 * default is 32bit, select 8bit only when requested.
386 		 */
387 		if (sconfig->dst_addr_width == DMA_SLAVE_BUSWIDTH_1_BYTE)
388 			mode |= OWL_DMA_MODE_NDDBW_8BIT;
389 
390 		break;
391 	case DMA_DEV_TO_MEM:
392 		 mode |= OWL_DMA_MODE_TS(vchan->drq)
393 			| OWL_DMA_MODE_ST_DEV | OWL_DMA_MODE_DT_DCU
394 			| OWL_DMA_MODE_SAM_CONST | OWL_DMA_MODE_DAM_INC;
395 
396 		/*
397 		 * Hardware only supports 32bit and 8bit buswidth. Since the
398 		 * default is 32bit, select 8bit only when requested.
399 		 */
400 		if (sconfig->src_addr_width == DMA_SLAVE_BUSWIDTH_1_BYTE)
401 			mode |= OWL_DMA_MODE_NDDBW_8BIT;
402 
403 		break;
404 	default:
405 		return -EINVAL;
406 	}
407 
408 	hw->next_lli = 0; /* One link list by default */
409 	hw->saddr = src;
410 	hw->daddr = dst;
411 
412 	hw->fcnt = 1; /* Frame count fixed as 1 */
413 	hw->flen = len; /* Max frame length is 1MB */
414 	hw->src_stride = 0;
415 	hw->dst_stride = 0;
416 	hw->ctrla = llc_hw_ctrla(mode,
417 				 OWL_DMA_LLC_SAV_LOAD_NEXT |
418 				 OWL_DMA_LLC_DAV_LOAD_NEXT);
419 
420 	if (is_cyclic)
421 		hw->ctrlb = llc_hw_ctrlb(OWL_DMA_INTCTL_BLOCK);
422 	else
423 		hw->ctrlb = llc_hw_ctrlb(OWL_DMA_INTCTL_SUPER_BLOCK);
424 
425 	return 0;
426 }
427 
428 static struct owl_dma_pchan *owl_dma_get_pchan(struct owl_dma *od,
429 					       struct owl_dma_vchan *vchan)
430 {
431 	struct owl_dma_pchan *pchan = NULL;
432 	unsigned long flags;
433 	int i;
434 
435 	for (i = 0; i < od->nr_pchans; i++) {
436 		pchan = &od->pchans[i];
437 
438 		spin_lock_irqsave(&od->lock, flags);
439 		if (!pchan->vchan) {
440 			pchan->vchan = vchan;
441 			spin_unlock_irqrestore(&od->lock, flags);
442 			break;
443 		}
444 
445 		spin_unlock_irqrestore(&od->lock, flags);
446 	}
447 
448 	return pchan;
449 }
450 
451 static int owl_dma_pchan_busy(struct owl_dma *od, struct owl_dma_pchan *pchan)
452 {
453 	unsigned int val;
454 
455 	val = dma_readl(od, OWL_DMA_IDLE_STAT);
456 
457 	return !(val & (1 << pchan->id));
458 }
459 
460 static void owl_dma_terminate_pchan(struct owl_dma *od,
461 				    struct owl_dma_pchan *pchan)
462 {
463 	unsigned long flags;
464 	u32 irq_pd;
465 
466 	pchan_writel(pchan, OWL_DMAX_START, 0);
467 	pchan_update(pchan, OWL_DMAX_INT_STATUS, 0xff, false);
468 
469 	spin_lock_irqsave(&od->lock, flags);
470 	dma_update(od, OWL_DMA_IRQ_EN0, (1 << pchan->id), false);
471 
472 	irq_pd = dma_readl(od, OWL_DMA_IRQ_PD0);
473 	if (irq_pd & (1 << pchan->id)) {
474 		dev_warn(od->dma.dev,
475 			 "terminating pchan %d that still has pending irq\n",
476 			 pchan->id);
477 		dma_writel(od, OWL_DMA_IRQ_PD0, (1 << pchan->id));
478 	}
479 
480 	pchan->vchan = NULL;
481 
482 	spin_unlock_irqrestore(&od->lock, flags);
483 }
484 
485 static void owl_dma_pause_pchan(struct owl_dma_pchan *pchan)
486 {
487 	pchan_writel(pchan, 1, OWL_DMAX_PAUSE);
488 }
489 
490 static void owl_dma_resume_pchan(struct owl_dma_pchan *pchan)
491 {
492 	pchan_writel(pchan, 0, OWL_DMAX_PAUSE);
493 }
494 
495 static int owl_dma_start_next_txd(struct owl_dma_vchan *vchan)
496 {
497 	struct owl_dma *od = to_owl_dma(vchan->vc.chan.device);
498 	struct virt_dma_desc *vd = vchan_next_desc(&vchan->vc);
499 	struct owl_dma_pchan *pchan = vchan->pchan;
500 	struct owl_dma_txd *txd = to_owl_txd(&vd->tx);
501 	struct owl_dma_lli *lli;
502 	unsigned long flags;
503 	u32 int_ctl;
504 
505 	list_del(&vd->node);
506 
507 	vchan->txd = txd;
508 
509 	/* Wait for channel inactive */
510 	while (owl_dma_pchan_busy(od, pchan))
511 		cpu_relax();
512 
513 	lli = list_first_entry(&txd->lli_list,
514 			       struct owl_dma_lli, node);
515 
516 	if (txd->cyclic)
517 		int_ctl = OWL_DMA_INTCTL_BLOCK;
518 	else
519 		int_ctl = OWL_DMA_INTCTL_SUPER_BLOCK;
520 
521 	pchan_writel(pchan, OWL_DMAX_MODE, OWL_DMA_MODE_LME);
522 	pchan_writel(pchan, OWL_DMAX_LINKLIST_CTL,
523 		     OWL_DMA_LLC_SAV_LOAD_NEXT | OWL_DMA_LLC_DAV_LOAD_NEXT);
524 	pchan_writel(pchan, OWL_DMAX_NEXT_DESCRIPTOR, lli->phys);
525 	pchan_writel(pchan, OWL_DMAX_INT_CTL, int_ctl);
526 
527 	/* Clear IRQ status for this pchan */
528 	pchan_update(pchan, OWL_DMAX_INT_STATUS, 0xff, false);
529 
530 	spin_lock_irqsave(&od->lock, flags);
531 
532 	dma_update(od, OWL_DMA_IRQ_EN0, (1 << pchan->id), true);
533 
534 	spin_unlock_irqrestore(&od->lock, flags);
535 
536 	dev_dbg(chan2dev(&vchan->vc.chan), "starting pchan %d\n", pchan->id);
537 
538 	/* Start DMA transfer for this pchan */
539 	pchan_writel(pchan, OWL_DMAX_START, 0x1);
540 
541 	return 0;
542 }
543 
544 static void owl_dma_phy_free(struct owl_dma *od, struct owl_dma_vchan *vchan)
545 {
546 	/* Ensure that the physical channel is stopped */
547 	owl_dma_terminate_pchan(od, vchan->pchan);
548 
549 	vchan->pchan = NULL;
550 }
551 
552 static irqreturn_t owl_dma_interrupt(int irq, void *dev_id)
553 {
554 	struct owl_dma *od = dev_id;
555 	struct owl_dma_vchan *vchan;
556 	struct owl_dma_pchan *pchan;
557 	unsigned long pending;
558 	int i;
559 	unsigned int global_irq_pending, chan_irq_pending;
560 
561 	spin_lock(&od->lock);
562 
563 	pending = dma_readl(od, OWL_DMA_IRQ_PD0);
564 
565 	/* Clear IRQ status for each pchan */
566 	for_each_set_bit(i, &pending, od->nr_pchans) {
567 		pchan = &od->pchans[i];
568 		pchan_update(pchan, OWL_DMAX_INT_STATUS, 0xff, false);
569 	}
570 
571 	/* Clear pending IRQ */
572 	dma_writel(od, OWL_DMA_IRQ_PD0, pending);
573 
574 	/* Check missed pending IRQ */
575 	for (i = 0; i < od->nr_pchans; i++) {
576 		pchan = &od->pchans[i];
577 		chan_irq_pending = pchan_readl(pchan, OWL_DMAX_INT_CTL) &
578 				   pchan_readl(pchan, OWL_DMAX_INT_STATUS);
579 
580 		/* Dummy read to ensure OWL_DMA_IRQ_PD0 value is updated */
581 		dma_readl(od, OWL_DMA_IRQ_PD0);
582 
583 		global_irq_pending = dma_readl(od, OWL_DMA_IRQ_PD0);
584 
585 		if (chan_irq_pending && !(global_irq_pending & BIT(i)))	{
586 			dev_dbg(od->dma.dev,
587 				"global and channel IRQ pending match err\n");
588 
589 			/* Clear IRQ status for this pchan */
590 			pchan_update(pchan, OWL_DMAX_INT_STATUS,
591 				     0xff, false);
592 
593 			/* Update global IRQ pending */
594 			pending |= BIT(i);
595 		}
596 	}
597 
598 	spin_unlock(&od->lock);
599 
600 	for_each_set_bit(i, &pending, od->nr_pchans) {
601 		struct owl_dma_txd *txd;
602 
603 		pchan = &od->pchans[i];
604 
605 		vchan = pchan->vchan;
606 		if (!vchan) {
607 			dev_warn(od->dma.dev, "no vchan attached on pchan %d\n",
608 				 pchan->id);
609 			continue;
610 		}
611 
612 		spin_lock(&vchan->vc.lock);
613 
614 		txd = vchan->txd;
615 		if (txd) {
616 			vchan->txd = NULL;
617 
618 			vchan_cookie_complete(&txd->vd);
619 
620 			/*
621 			 * Start the next descriptor (if any),
622 			 * otherwise free this channel.
623 			 */
624 			if (vchan_next_desc(&vchan->vc))
625 				owl_dma_start_next_txd(vchan);
626 			else
627 				owl_dma_phy_free(od, vchan);
628 		}
629 
630 		spin_unlock(&vchan->vc.lock);
631 	}
632 
633 	return IRQ_HANDLED;
634 }
635 
636 static void owl_dma_free_txd(struct owl_dma *od, struct owl_dma_txd *txd)
637 {
638 	struct owl_dma_lli *lli, *_lli;
639 
640 	if (unlikely(!txd))
641 		return;
642 
643 	list_for_each_entry_safe(lli, _lli, &txd->lli_list, node)
644 		owl_dma_free_lli(od, lli);
645 
646 	kfree(txd);
647 }
648 
649 static void owl_dma_desc_free(struct virt_dma_desc *vd)
650 {
651 	struct owl_dma *od = to_owl_dma(vd->tx.chan->device);
652 	struct owl_dma_txd *txd = to_owl_txd(&vd->tx);
653 
654 	owl_dma_free_txd(od, txd);
655 }
656 
657 static int owl_dma_terminate_all(struct dma_chan *chan)
658 {
659 	struct owl_dma *od = to_owl_dma(chan->device);
660 	struct owl_dma_vchan *vchan = to_owl_vchan(chan);
661 	unsigned long flags;
662 	LIST_HEAD(head);
663 
664 	spin_lock_irqsave(&vchan->vc.lock, flags);
665 
666 	if (vchan->pchan)
667 		owl_dma_phy_free(od, vchan);
668 
669 	if (vchan->txd) {
670 		owl_dma_desc_free(&vchan->txd->vd);
671 		vchan->txd = NULL;
672 	}
673 
674 	vchan_get_all_descriptors(&vchan->vc, &head);
675 
676 	spin_unlock_irqrestore(&vchan->vc.lock, flags);
677 
678 	vchan_dma_desc_free_list(&vchan->vc, &head);
679 
680 	return 0;
681 }
682 
683 static int owl_dma_config(struct dma_chan *chan,
684 			  struct dma_slave_config *config)
685 {
686 	struct owl_dma_vchan *vchan = to_owl_vchan(chan);
687 
688 	/* Reject definitely invalid configurations */
689 	if (config->src_addr_width == DMA_SLAVE_BUSWIDTH_8_BYTES ||
690 	    config->dst_addr_width == DMA_SLAVE_BUSWIDTH_8_BYTES)
691 		return -EINVAL;
692 
693 	memcpy(&vchan->cfg, config, sizeof(struct dma_slave_config));
694 
695 	return 0;
696 }
697 
698 static int owl_dma_pause(struct dma_chan *chan)
699 {
700 	struct owl_dma_vchan *vchan = to_owl_vchan(chan);
701 	unsigned long flags;
702 
703 	spin_lock_irqsave(&vchan->vc.lock, flags);
704 
705 	owl_dma_pause_pchan(vchan->pchan);
706 
707 	spin_unlock_irqrestore(&vchan->vc.lock, flags);
708 
709 	return 0;
710 }
711 
712 static int owl_dma_resume(struct dma_chan *chan)
713 {
714 	struct owl_dma_vchan *vchan = to_owl_vchan(chan);
715 	unsigned long flags;
716 
717 	if (!vchan->pchan && !vchan->txd)
718 		return 0;
719 
720 	dev_dbg(chan2dev(chan), "vchan %p: resume\n", &vchan->vc);
721 
722 	spin_lock_irqsave(&vchan->vc.lock, flags);
723 
724 	owl_dma_resume_pchan(vchan->pchan);
725 
726 	spin_unlock_irqrestore(&vchan->vc.lock, flags);
727 
728 	return 0;
729 }
730 
731 static u32 owl_dma_getbytes_chan(struct owl_dma_vchan *vchan)
732 {
733 	struct owl_dma_pchan *pchan;
734 	struct owl_dma_txd *txd;
735 	struct owl_dma_lli *lli;
736 	unsigned int next_lli_phy;
737 	size_t bytes;
738 
739 	pchan = vchan->pchan;
740 	txd = vchan->txd;
741 
742 	if (!pchan || !txd)
743 		return 0;
744 
745 	/* Get remain count of current node in link list */
746 	bytes = pchan_readl(pchan, OWL_DMAX_REMAIN_CNT);
747 
748 	/* Loop through the preceding nodes to get total remaining bytes */
749 	if (pchan_readl(pchan, OWL_DMAX_MODE) & OWL_DMA_MODE_LME) {
750 		next_lli_phy = pchan_readl(pchan, OWL_DMAX_NEXT_DESCRIPTOR);
751 		list_for_each_entry(lli, &txd->lli_list, node) {
752 			/* Start from the next active node */
753 			if (lli->phys == next_lli_phy) {
754 				list_for_each_entry(lli, &txd->lli_list, node)
755 					bytes += lli->hw.flen;
756 				break;
757 			}
758 		}
759 	}
760 
761 	return bytes;
762 }
763 
764 static enum dma_status owl_dma_tx_status(struct dma_chan *chan,
765 					 dma_cookie_t cookie,
766 					 struct dma_tx_state *state)
767 {
768 	struct owl_dma_vchan *vchan = to_owl_vchan(chan);
769 	struct owl_dma_lli *lli;
770 	struct virt_dma_desc *vd;
771 	struct owl_dma_txd *txd;
772 	enum dma_status ret;
773 	unsigned long flags;
774 	size_t bytes = 0;
775 
776 	ret = dma_cookie_status(chan, cookie, state);
777 	if (ret == DMA_COMPLETE || !state)
778 		return ret;
779 
780 	spin_lock_irqsave(&vchan->vc.lock, flags);
781 
782 	vd = vchan_find_desc(&vchan->vc, cookie);
783 	if (vd) {
784 		txd = to_owl_txd(&vd->tx);
785 		list_for_each_entry(lli, &txd->lli_list, node)
786 			bytes += lli->hw.flen;
787 	} else {
788 		bytes = owl_dma_getbytes_chan(vchan);
789 	}
790 
791 	spin_unlock_irqrestore(&vchan->vc.lock, flags);
792 
793 	dma_set_residue(state, bytes);
794 
795 	return ret;
796 }
797 
798 static void owl_dma_phy_alloc_and_start(struct owl_dma_vchan *vchan)
799 {
800 	struct owl_dma *od = to_owl_dma(vchan->vc.chan.device);
801 	struct owl_dma_pchan *pchan;
802 
803 	pchan = owl_dma_get_pchan(od, vchan);
804 	if (!pchan)
805 		return;
806 
807 	dev_dbg(od->dma.dev, "allocated pchan %d\n", pchan->id);
808 
809 	vchan->pchan = pchan;
810 	owl_dma_start_next_txd(vchan);
811 }
812 
813 static void owl_dma_issue_pending(struct dma_chan *chan)
814 {
815 	struct owl_dma_vchan *vchan = to_owl_vchan(chan);
816 	unsigned long flags;
817 
818 	spin_lock_irqsave(&vchan->vc.lock, flags);
819 	if (vchan_issue_pending(&vchan->vc)) {
820 		if (!vchan->pchan)
821 			owl_dma_phy_alloc_and_start(vchan);
822 	}
823 	spin_unlock_irqrestore(&vchan->vc.lock, flags);
824 }
825 
826 static struct dma_async_tx_descriptor
827 		*owl_dma_prep_memcpy(struct dma_chan *chan,
828 				     dma_addr_t dst, dma_addr_t src,
829 				     size_t len, unsigned long flags)
830 {
831 	struct owl_dma *od = to_owl_dma(chan->device);
832 	struct owl_dma_vchan *vchan = to_owl_vchan(chan);
833 	struct owl_dma_txd *txd;
834 	struct owl_dma_lli *lli, *prev = NULL;
835 	size_t offset, bytes;
836 	int ret;
837 
838 	if (!len)
839 		return NULL;
840 
841 	txd = kzalloc(sizeof(*txd), GFP_NOWAIT);
842 	if (!txd)
843 		return NULL;
844 
845 	INIT_LIST_HEAD(&txd->lli_list);
846 
847 	/* Process the transfer as frame by frame */
848 	for (offset = 0; offset < len; offset += bytes) {
849 		lli = owl_dma_alloc_lli(od);
850 		if (!lli) {
851 			dev_warn(chan2dev(chan), "failed to allocate lli\n");
852 			goto err_txd_free;
853 		}
854 
855 		bytes = min_t(size_t, (len - offset), OWL_DMA_FRAME_MAX_LENGTH);
856 
857 		ret = owl_dma_cfg_lli(vchan, lli, src + offset, dst + offset,
858 				      bytes, DMA_MEM_TO_MEM,
859 				      &vchan->cfg, txd->cyclic);
860 		if (ret) {
861 			dev_warn(chan2dev(chan), "failed to config lli\n");
862 			goto err_txd_free;
863 		}
864 
865 		prev = owl_dma_add_lli(txd, prev, lli, false);
866 	}
867 
868 	return vchan_tx_prep(&vchan->vc, &txd->vd, flags);
869 
870 err_txd_free:
871 	owl_dma_free_txd(od, txd);
872 	return NULL;
873 }
874 
875 static struct dma_async_tx_descriptor
876 		*owl_dma_prep_slave_sg(struct dma_chan *chan,
877 				       struct scatterlist *sgl,
878 				       unsigned int sg_len,
879 				       enum dma_transfer_direction dir,
880 				       unsigned long flags, void *context)
881 {
882 	struct owl_dma *od = to_owl_dma(chan->device);
883 	struct owl_dma_vchan *vchan = to_owl_vchan(chan);
884 	struct dma_slave_config *sconfig = &vchan->cfg;
885 	struct owl_dma_txd *txd;
886 	struct owl_dma_lli *lli, *prev = NULL;
887 	struct scatterlist *sg;
888 	dma_addr_t addr, src = 0, dst = 0;
889 	size_t len;
890 	int ret, i;
891 
892 	txd = kzalloc(sizeof(*txd), GFP_NOWAIT);
893 	if (!txd)
894 		return NULL;
895 
896 	INIT_LIST_HEAD(&txd->lli_list);
897 
898 	for_each_sg(sgl, sg, sg_len, i) {
899 		addr = sg_dma_address(sg);
900 		len = sg_dma_len(sg);
901 
902 		if (len > OWL_DMA_FRAME_MAX_LENGTH) {
903 			dev_err(od->dma.dev,
904 				"frame length exceeds max supported length");
905 			goto err_txd_free;
906 		}
907 
908 		lli = owl_dma_alloc_lli(od);
909 		if (!lli) {
910 			dev_err(chan2dev(chan), "failed to allocate lli");
911 			goto err_txd_free;
912 		}
913 
914 		if (dir == DMA_MEM_TO_DEV) {
915 			src = addr;
916 			dst = sconfig->dst_addr;
917 		} else {
918 			src = sconfig->src_addr;
919 			dst = addr;
920 		}
921 
922 		ret = owl_dma_cfg_lli(vchan, lli, src, dst, len, dir, sconfig,
923 				      txd->cyclic);
924 		if (ret) {
925 			dev_warn(chan2dev(chan), "failed to config lli");
926 			goto err_txd_free;
927 		}
928 
929 		prev = owl_dma_add_lli(txd, prev, lli, false);
930 	}
931 
932 	return vchan_tx_prep(&vchan->vc, &txd->vd, flags);
933 
934 err_txd_free:
935 	owl_dma_free_txd(od, txd);
936 
937 	return NULL;
938 }
939 
940 static struct dma_async_tx_descriptor
941 		*owl_prep_dma_cyclic(struct dma_chan *chan,
942 				     dma_addr_t buf_addr, size_t buf_len,
943 				     size_t period_len,
944 				     enum dma_transfer_direction dir,
945 				     unsigned long flags)
946 {
947 	struct owl_dma *od = to_owl_dma(chan->device);
948 	struct owl_dma_vchan *vchan = to_owl_vchan(chan);
949 	struct dma_slave_config *sconfig = &vchan->cfg;
950 	struct owl_dma_txd *txd;
951 	struct owl_dma_lli *lli, *prev = NULL, *first = NULL;
952 	dma_addr_t src = 0, dst = 0;
953 	unsigned int periods = buf_len / period_len;
954 	int ret, i;
955 
956 	txd = kzalloc(sizeof(*txd), GFP_NOWAIT);
957 	if (!txd)
958 		return NULL;
959 
960 	INIT_LIST_HEAD(&txd->lli_list);
961 	txd->cyclic = true;
962 
963 	for (i = 0; i < periods; i++) {
964 		lli = owl_dma_alloc_lli(od);
965 		if (!lli) {
966 			dev_warn(chan2dev(chan), "failed to allocate lli");
967 			goto err_txd_free;
968 		}
969 
970 		if (dir == DMA_MEM_TO_DEV) {
971 			src = buf_addr + (period_len * i);
972 			dst = sconfig->dst_addr;
973 		} else if (dir == DMA_DEV_TO_MEM) {
974 			src = sconfig->src_addr;
975 			dst = buf_addr + (period_len * i);
976 		}
977 
978 		ret = owl_dma_cfg_lli(vchan, lli, src, dst, period_len,
979 				      dir, sconfig, txd->cyclic);
980 		if (ret) {
981 			dev_warn(chan2dev(chan), "failed to config lli");
982 			goto err_txd_free;
983 		}
984 
985 		if (!first)
986 			first = lli;
987 
988 		prev = owl_dma_add_lli(txd, prev, lli, false);
989 	}
990 
991 	/* close the cyclic list */
992 	owl_dma_add_lli(txd, prev, first, true);
993 
994 	return vchan_tx_prep(&vchan->vc, &txd->vd, flags);
995 
996 err_txd_free:
997 	owl_dma_free_txd(od, txd);
998 
999 	return NULL;
1000 }
1001 
1002 static void owl_dma_free_chan_resources(struct dma_chan *chan)
1003 {
1004 	struct owl_dma_vchan *vchan = to_owl_vchan(chan);
1005 
1006 	/* Ensure all queued descriptors are freed */
1007 	vchan_free_chan_resources(&vchan->vc);
1008 }
1009 
1010 static inline void owl_dma_free(struct owl_dma *od)
1011 {
1012 	struct owl_dma_vchan *vchan = NULL;
1013 	struct owl_dma_vchan *next;
1014 
1015 	list_for_each_entry_safe(vchan,
1016 				 next, &od->dma.channels, vc.chan.device_node) {
1017 		list_del(&vchan->vc.chan.device_node);
1018 		tasklet_kill(&vchan->vc.task);
1019 	}
1020 }
1021 
1022 static struct dma_chan *owl_dma_of_xlate(struct of_phandle_args *dma_spec,
1023 					 struct of_dma *ofdma)
1024 {
1025 	struct owl_dma *od = ofdma->of_dma_data;
1026 	struct owl_dma_vchan *vchan;
1027 	struct dma_chan *chan;
1028 	u8 drq = dma_spec->args[0];
1029 
1030 	if (drq > od->nr_vchans)
1031 		return NULL;
1032 
1033 	chan = dma_get_any_slave_channel(&od->dma);
1034 	if (!chan)
1035 		return NULL;
1036 
1037 	vchan = to_owl_vchan(chan);
1038 	vchan->drq = drq;
1039 
1040 	return chan;
1041 }
1042 
1043 static int owl_dma_probe(struct platform_device *pdev)
1044 {
1045 	struct device_node *np = pdev->dev.of_node;
1046 	struct owl_dma *od;
1047 	int ret, i, nr_channels, nr_requests;
1048 
1049 	od = devm_kzalloc(&pdev->dev, sizeof(*od), GFP_KERNEL);
1050 	if (!od)
1051 		return -ENOMEM;
1052 
1053 	od->base = devm_platform_ioremap_resource(pdev, 0);
1054 	if (IS_ERR(od->base))
1055 		return PTR_ERR(od->base);
1056 
1057 	ret = of_property_read_u32(np, "dma-channels", &nr_channels);
1058 	if (ret) {
1059 		dev_err(&pdev->dev, "can't get dma-channels\n");
1060 		return ret;
1061 	}
1062 
1063 	ret = of_property_read_u32(np, "dma-requests", &nr_requests);
1064 	if (ret) {
1065 		dev_err(&pdev->dev, "can't get dma-requests\n");
1066 		return ret;
1067 	}
1068 
1069 	dev_info(&pdev->dev, "dma-channels %d, dma-requests %d\n",
1070 		 nr_channels, nr_requests);
1071 
1072 	od->nr_pchans = nr_channels;
1073 	od->nr_vchans = nr_requests;
1074 
1075 	pdev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
1076 
1077 	platform_set_drvdata(pdev, od);
1078 	spin_lock_init(&od->lock);
1079 
1080 	dma_cap_set(DMA_MEMCPY, od->dma.cap_mask);
1081 	dma_cap_set(DMA_SLAVE, od->dma.cap_mask);
1082 	dma_cap_set(DMA_CYCLIC, od->dma.cap_mask);
1083 
1084 	od->dma.dev = &pdev->dev;
1085 	od->dma.device_free_chan_resources = owl_dma_free_chan_resources;
1086 	od->dma.device_tx_status = owl_dma_tx_status;
1087 	od->dma.device_issue_pending = owl_dma_issue_pending;
1088 	od->dma.device_prep_dma_memcpy = owl_dma_prep_memcpy;
1089 	od->dma.device_prep_slave_sg = owl_dma_prep_slave_sg;
1090 	od->dma.device_prep_dma_cyclic = owl_prep_dma_cyclic;
1091 	od->dma.device_config = owl_dma_config;
1092 	od->dma.device_pause = owl_dma_pause;
1093 	od->dma.device_resume = owl_dma_resume;
1094 	od->dma.device_terminate_all = owl_dma_terminate_all;
1095 	od->dma.src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
1096 	od->dma.dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
1097 	od->dma.directions = BIT(DMA_MEM_TO_MEM);
1098 	od->dma.residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
1099 
1100 	INIT_LIST_HEAD(&od->dma.channels);
1101 
1102 	od->clk = devm_clk_get(&pdev->dev, NULL);
1103 	if (IS_ERR(od->clk)) {
1104 		dev_err(&pdev->dev, "unable to get clock\n");
1105 		return PTR_ERR(od->clk);
1106 	}
1107 
1108 	/*
1109 	 * Eventhough the DMA controller is capable of generating 4
1110 	 * IRQ's for DMA priority feature, we only use 1 IRQ for
1111 	 * simplification.
1112 	 */
1113 	od->irq = platform_get_irq(pdev, 0);
1114 	ret = devm_request_irq(&pdev->dev, od->irq, owl_dma_interrupt, 0,
1115 			       dev_name(&pdev->dev), od);
1116 	if (ret) {
1117 		dev_err(&pdev->dev, "unable to request IRQ\n");
1118 		return ret;
1119 	}
1120 
1121 	/* Init physical channel */
1122 	od->pchans = devm_kcalloc(&pdev->dev, od->nr_pchans,
1123 				  sizeof(struct owl_dma_pchan), GFP_KERNEL);
1124 	if (!od->pchans)
1125 		return -ENOMEM;
1126 
1127 	for (i = 0; i < od->nr_pchans; i++) {
1128 		struct owl_dma_pchan *pchan = &od->pchans[i];
1129 
1130 		pchan->id = i;
1131 		pchan->base = od->base + OWL_DMA_CHAN_BASE(i);
1132 	}
1133 
1134 	/* Init virtual channel */
1135 	od->vchans = devm_kcalloc(&pdev->dev, od->nr_vchans,
1136 				  sizeof(struct owl_dma_vchan), GFP_KERNEL);
1137 	if (!od->vchans)
1138 		return -ENOMEM;
1139 
1140 	for (i = 0; i < od->nr_vchans; i++) {
1141 		struct owl_dma_vchan *vchan = &od->vchans[i];
1142 
1143 		vchan->vc.desc_free = owl_dma_desc_free;
1144 		vchan_init(&vchan->vc, &od->dma);
1145 	}
1146 
1147 	/* Create a pool of consistent memory blocks for hardware descriptors */
1148 	od->lli_pool = dma_pool_create(dev_name(od->dma.dev), od->dma.dev,
1149 				       sizeof(struct owl_dma_lli),
1150 				       __alignof__(struct owl_dma_lli),
1151 				       0);
1152 	if (!od->lli_pool) {
1153 		dev_err(&pdev->dev, "unable to allocate DMA descriptor pool\n");
1154 		return -ENOMEM;
1155 	}
1156 
1157 	clk_prepare_enable(od->clk);
1158 
1159 	ret = dma_async_device_register(&od->dma);
1160 	if (ret) {
1161 		dev_err(&pdev->dev, "failed to register DMA engine device\n");
1162 		goto err_pool_free;
1163 	}
1164 
1165 	/* Device-tree DMA controller registration */
1166 	ret = of_dma_controller_register(pdev->dev.of_node,
1167 					 owl_dma_of_xlate, od);
1168 	if (ret) {
1169 		dev_err(&pdev->dev, "of_dma_controller_register failed\n");
1170 		goto err_dma_unregister;
1171 	}
1172 
1173 	return 0;
1174 
1175 err_dma_unregister:
1176 	dma_async_device_unregister(&od->dma);
1177 err_pool_free:
1178 	clk_disable_unprepare(od->clk);
1179 	dma_pool_destroy(od->lli_pool);
1180 
1181 	return ret;
1182 }
1183 
1184 static int owl_dma_remove(struct platform_device *pdev)
1185 {
1186 	struct owl_dma *od = platform_get_drvdata(pdev);
1187 
1188 	of_dma_controller_free(pdev->dev.of_node);
1189 	dma_async_device_unregister(&od->dma);
1190 
1191 	/* Mask all interrupts for this execution environment */
1192 	dma_writel(od, OWL_DMA_IRQ_EN0, 0x0);
1193 
1194 	/* Make sure we won't have any further interrupts */
1195 	devm_free_irq(od->dma.dev, od->irq, od);
1196 
1197 	owl_dma_free(od);
1198 
1199 	clk_disable_unprepare(od->clk);
1200 
1201 	return 0;
1202 }
1203 
1204 static const struct of_device_id owl_dma_match[] = {
1205 	{ .compatible = "actions,s900-dma", },
1206 	{ /* sentinel */ }
1207 };
1208 MODULE_DEVICE_TABLE(of, owl_dma_match);
1209 
1210 static struct platform_driver owl_dma_driver = {
1211 	.probe	= owl_dma_probe,
1212 	.remove	= owl_dma_remove,
1213 	.driver = {
1214 		.name = "dma-owl",
1215 		.of_match_table = of_match_ptr(owl_dma_match),
1216 	},
1217 };
1218 
1219 static int owl_dma_init(void)
1220 {
1221 	return platform_driver_register(&owl_dma_driver);
1222 }
1223 subsys_initcall(owl_dma_init);
1224 
1225 static void __exit owl_dma_exit(void)
1226 {
1227 	platform_driver_unregister(&owl_dma_driver);
1228 }
1229 module_exit(owl_dma_exit);
1230 
1231 MODULE_AUTHOR("David Liu <liuwei@actions-semi.com>");
1232 MODULE_AUTHOR("Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>");
1233 MODULE_DESCRIPTION("Actions Semi Owl SoCs DMA driver");
1234 MODULE_LICENSE("GPL");
1235