xref: /linux/drivers/dma/at_xdmac.c (revision 4949009eb8d40a441dcddcd96e101e77d31cf1b2)
1 /*
2  * Driver for the Atmel Extensible DMA Controller (aka XDMAC on AT91 systems)
3  *
4  * Copyright (C) 2014 Atmel Corporation
5  *
6  * Author: Ludovic Desroches <ludovic.desroches@atmel.com>
7  *
8  * This program is free software; you can redistribute it and/or modify it
9  * under the terms of the GNU General Public License version 2 as published by
10  * the Free Software Foundation.
11  *
12  * This program is distributed in the hope that it will be useful, but WITHOUT
13  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
15  * more details.
16  *
17  * You should have received a copy of the GNU General Public License along with
18  * this program.  If not, see <http://www.gnu.org/licenses/>.
19  */
20 
21 #include <asm/barrier.h>
22 #include <dt-bindings/dma/at91.h>
23 #include <linux/clk.h>
24 #include <linux/dmaengine.h>
25 #include <linux/dmapool.h>
26 #include <linux/interrupt.h>
27 #include <linux/irq.h>
28 #include <linux/list.h>
29 #include <linux/module.h>
30 #include <linux/of_dma.h>
31 #include <linux/of_platform.h>
32 #include <linux/platform_device.h>
33 #include <linux/pm.h>
34 
35 #include "dmaengine.h"
36 
37 /* Global registers */
38 #define AT_XDMAC_GTYPE		0x00	/* Global Type Register */
39 #define		AT_XDMAC_NB_CH(i)	(((i) & 0x1F) + 1)		/* Number of Channels Minus One */
40 #define		AT_XDMAC_FIFO_SZ(i)	(((i) >> 5) & 0x7FF)		/* Number of Bytes */
41 #define		AT_XDMAC_NB_REQ(i)	((((i) >> 16) & 0x3F) + 1)	/* Number of Peripheral Requests Minus One */
42 #define AT_XDMAC_GCFG		0x04	/* Global Configuration Register */
43 #define AT_XDMAC_GWAC		0x08	/* Global Weighted Arbiter Configuration Register */
44 #define AT_XDMAC_GIE		0x0C	/* Global Interrupt Enable Register */
45 #define AT_XDMAC_GID		0x10	/* Global Interrupt Disable Register */
46 #define AT_XDMAC_GIM		0x14	/* Global Interrupt Mask Register */
47 #define AT_XDMAC_GIS		0x18	/* Global Interrupt Status Register */
48 #define AT_XDMAC_GE		0x1C	/* Global Channel Enable Register */
49 #define AT_XDMAC_GD		0x20	/* Global Channel Disable Register */
50 #define AT_XDMAC_GS		0x24	/* Global Channel Status Register */
51 #define AT_XDMAC_GRS		0x28	/* Global Channel Read Suspend Register */
52 #define AT_XDMAC_GWS		0x2C	/* Global Write Suspend Register */
53 #define AT_XDMAC_GRWS		0x30	/* Global Channel Read Write Suspend Register */
54 #define AT_XDMAC_GRWR		0x34	/* Global Channel Read Write Resume Register */
55 #define AT_XDMAC_GSWR		0x38	/* Global Channel Software Request Register */
56 #define AT_XDMAC_GSWS		0x3C	/* Global channel Software Request Status Register */
57 #define AT_XDMAC_GSWF		0x40	/* Global Channel Software Flush Request Register */
58 #define AT_XDMAC_VERSION	0xFFC	/* XDMAC Version Register */
59 
60 /* Channel relative registers offsets */
61 #define AT_XDMAC_CIE		0x00	/* Channel Interrupt Enable Register */
62 #define		AT_XDMAC_CIE_BIE	BIT(0)	/* End of Block Interrupt Enable Bit */
63 #define		AT_XDMAC_CIE_LIE	BIT(1)	/* End of Linked List Interrupt Enable Bit */
64 #define		AT_XDMAC_CIE_DIE	BIT(2)	/* End of Disable Interrupt Enable Bit */
65 #define		AT_XDMAC_CIE_FIE	BIT(3)	/* End of Flush Interrupt Enable Bit */
66 #define		AT_XDMAC_CIE_RBEIE	BIT(4)	/* Read Bus Error Interrupt Enable Bit */
67 #define		AT_XDMAC_CIE_WBEIE	BIT(5)	/* Write Bus Error Interrupt Enable Bit */
68 #define		AT_XDMAC_CIE_ROIE	BIT(6)	/* Request Overflow Interrupt Enable Bit */
69 #define AT_XDMAC_CID		0x04	/* Channel Interrupt Disable Register */
70 #define		AT_XDMAC_CID_BID	BIT(0)	/* End of Block Interrupt Disable Bit */
71 #define		AT_XDMAC_CID_LID	BIT(1)	/* End of Linked List Interrupt Disable Bit */
72 #define		AT_XDMAC_CID_DID	BIT(2)	/* End of Disable Interrupt Disable Bit */
73 #define		AT_XDMAC_CID_FID	BIT(3)	/* End of Flush Interrupt Disable Bit */
74 #define		AT_XDMAC_CID_RBEID	BIT(4)	/* Read Bus Error Interrupt Disable Bit */
75 #define		AT_XDMAC_CID_WBEID	BIT(5)	/* Write Bus Error Interrupt Disable Bit */
76 #define		AT_XDMAC_CID_ROID	BIT(6)	/* Request Overflow Interrupt Disable Bit */
77 #define AT_XDMAC_CIM		0x08	/* Channel Interrupt Mask Register */
78 #define		AT_XDMAC_CIM_BIM	BIT(0)	/* End of Block Interrupt Mask Bit */
79 #define		AT_XDMAC_CIM_LIM	BIT(1)	/* End of Linked List Interrupt Mask Bit */
80 #define		AT_XDMAC_CIM_DIM	BIT(2)	/* End of Disable Interrupt Mask Bit */
81 #define		AT_XDMAC_CIM_FIM	BIT(3)	/* End of Flush Interrupt Mask Bit */
82 #define		AT_XDMAC_CIM_RBEIM	BIT(4)	/* Read Bus Error Interrupt Mask Bit */
83 #define		AT_XDMAC_CIM_WBEIM	BIT(5)	/* Write Bus Error Interrupt Mask Bit */
84 #define		AT_XDMAC_CIM_ROIM	BIT(6)	/* Request Overflow Interrupt Mask Bit */
85 #define AT_XDMAC_CIS		0x0C	/* Channel Interrupt Status Register */
86 #define		AT_XDMAC_CIS_BIS	BIT(0)	/* End of Block Interrupt Status Bit */
87 #define		AT_XDMAC_CIS_LIS	BIT(1)	/* End of Linked List Interrupt Status Bit */
88 #define		AT_XDMAC_CIS_DIS	BIT(2)	/* End of Disable Interrupt Status Bit */
89 #define		AT_XDMAC_CIS_FIS	BIT(3)	/* End of Flush Interrupt Status Bit */
90 #define		AT_XDMAC_CIS_RBEIS	BIT(4)	/* Read Bus Error Interrupt Status Bit */
91 #define		AT_XDMAC_CIS_WBEIS	BIT(5)	/* Write Bus Error Interrupt Status Bit */
92 #define		AT_XDMAC_CIS_ROIS	BIT(6)	/* Request Overflow Interrupt Status Bit */
93 #define AT_XDMAC_CSA		0x10	/* Channel Source Address Register */
94 #define AT_XDMAC_CDA		0x14	/* Channel Destination Address Register */
95 #define AT_XDMAC_CNDA		0x18	/* Channel Next Descriptor Address Register */
96 #define		AT_XDMAC_CNDA_NDAIF(i)	((i) & 0x1)			/* Channel x Next Descriptor Interface */
97 #define		AT_XDMAC_CNDA_NDA(i)	((i) & 0xfffffffc)		/* Channel x Next Descriptor Address */
98 #define AT_XDMAC_CNDC		0x1C	/* Channel Next Descriptor Control Register */
99 #define		AT_XDMAC_CNDC_NDE		(0x1 << 0)		/* Channel x Next Descriptor Enable */
100 #define		AT_XDMAC_CNDC_NDSUP		(0x1 << 1)		/* Channel x Next Descriptor Source Update */
101 #define		AT_XDMAC_CNDC_NDDUP		(0x1 << 2)		/* Channel x Next Descriptor Destination Update */
102 #define		AT_XDMAC_CNDC_NDVIEW_NDV0	(0x0 << 3)		/* Channel x Next Descriptor View 0 */
103 #define		AT_XDMAC_CNDC_NDVIEW_NDV1	(0x1 << 3)		/* Channel x Next Descriptor View 1 */
104 #define		AT_XDMAC_CNDC_NDVIEW_NDV2	(0x2 << 3)		/* Channel x Next Descriptor View 2 */
105 #define		AT_XDMAC_CNDC_NDVIEW_NDV3	(0x3 << 3)		/* Channel x Next Descriptor View 3 */
106 #define AT_XDMAC_CUBC		0x20	/* Channel Microblock Control Register */
107 #define AT_XDMAC_CBC		0x24	/* Channel Block Control Register */
108 #define AT_XDMAC_CC		0x28	/* Channel Configuration Register */
109 #define		AT_XDMAC_CC_TYPE	(0x1 << 0)	/* Channel Transfer Type */
110 #define			AT_XDMAC_CC_TYPE_MEM_TRAN	(0x0 << 0)	/* Memory to Memory Transfer */
111 #define			AT_XDMAC_CC_TYPE_PER_TRAN	(0x1 << 0)	/* Peripheral to Memory or Memory to Peripheral Transfer */
112 #define		AT_XDMAC_CC_MBSIZE_MASK	(0x3 << 1)
113 #define			AT_XDMAC_CC_MBSIZE_SINGLE	(0x0 << 1)
114 #define			AT_XDMAC_CC_MBSIZE_FOUR		(0x1 << 1)
115 #define			AT_XDMAC_CC_MBSIZE_EIGHT	(0x2 << 1)
116 #define			AT_XDMAC_CC_MBSIZE_SIXTEEN	(0x3 << 1)
117 #define		AT_XDMAC_CC_DSYNC	(0x1 << 4)	/* Channel Synchronization */
118 #define			AT_XDMAC_CC_DSYNC_PER2MEM	(0x0 << 4)
119 #define			AT_XDMAC_CC_DSYNC_MEM2PER	(0x1 << 4)
120 #define		AT_XDMAC_CC_PROT	(0x1 << 5)	/* Channel Protection */
121 #define			AT_XDMAC_CC_PROT_SEC		(0x0 << 5)
122 #define			AT_XDMAC_CC_PROT_UNSEC		(0x1 << 5)
123 #define		AT_XDMAC_CC_SWREQ	(0x1 << 6)	/* Channel Software Request Trigger */
124 #define			AT_XDMAC_CC_SWREQ_HWR_CONNECTED	(0x0 << 6)
125 #define			AT_XDMAC_CC_SWREQ_SWR_CONNECTED	(0x1 << 6)
126 #define		AT_XDMAC_CC_MEMSET	(0x1 << 7)	/* Channel Fill Block of memory */
127 #define			AT_XDMAC_CC_MEMSET_NORMAL_MODE	(0x0 << 7)
128 #define			AT_XDMAC_CC_MEMSET_HW_MODE	(0x1 << 7)
129 #define		AT_XDMAC_CC_CSIZE(i)	((0x7 & (i)) << 8)	/* Channel Chunk Size */
130 #define		AT_XDMAC_CC_DWIDTH_OFFSET	11
131 #define		AT_XDMAC_CC_DWIDTH_MASK	(0x3 << AT_XDMAC_CC_DWIDTH_OFFSET)
132 #define		AT_XDMAC_CC_DWIDTH(i)	((0x3 & (i)) << AT_XDMAC_CC_DWIDTH_OFFSET)	/* Channel Data Width */
133 #define			AT_XDMAC_CC_DWIDTH_BYTE		0x0
134 #define			AT_XDMAC_CC_DWIDTH_HALFWORD	0x1
135 #define			AT_XDMAC_CC_DWIDTH_WORD		0x2
136 #define			AT_XDMAC_CC_DWIDTH_DWORD	0x3
137 #define		AT_XDMAC_CC_SIF(i)	((0x1 & (i)) << 13)	/* Channel Source Interface Identifier */
138 #define		AT_XDMAC_CC_DIF(i)	((0x1 & (i)) << 14)	/* Channel Destination Interface Identifier */
139 #define		AT_XDMAC_CC_SAM_MASK	(0x3 << 16)	/* Channel Source Addressing Mode */
140 #define			AT_XDMAC_CC_SAM_FIXED_AM	(0x0 << 16)
141 #define			AT_XDMAC_CC_SAM_INCREMENTED_AM	(0x1 << 16)
142 #define			AT_XDMAC_CC_SAM_UBS_AM		(0x2 << 16)
143 #define			AT_XDMAC_CC_SAM_UBS_DS_AM	(0x3 << 16)
144 #define		AT_XDMAC_CC_DAM_MASK	(0x3 << 18)	/* Channel Source Addressing Mode */
145 #define			AT_XDMAC_CC_DAM_FIXED_AM	(0x0 << 18)
146 #define			AT_XDMAC_CC_DAM_INCREMENTED_AM	(0x1 << 18)
147 #define			AT_XDMAC_CC_DAM_UBS_AM		(0x2 << 18)
148 #define			AT_XDMAC_CC_DAM_UBS_DS_AM	(0x3 << 18)
149 #define		AT_XDMAC_CC_INITD	(0x1 << 21)	/* Channel Initialization Terminated (read only) */
150 #define			AT_XDMAC_CC_INITD_TERMINATED	(0x0 << 21)
151 #define			AT_XDMAC_CC_INITD_IN_PROGRESS	(0x1 << 21)
152 #define		AT_XDMAC_CC_RDIP	(0x1 << 22)	/* Read in Progress (read only) */
153 #define			AT_XDMAC_CC_RDIP_DONE		(0x0 << 22)
154 #define			AT_XDMAC_CC_RDIP_IN_PROGRESS	(0x1 << 22)
155 #define		AT_XDMAC_CC_WRIP	(0x1 << 23)	/* Write in Progress (read only) */
156 #define			AT_XDMAC_CC_WRIP_DONE		(0x0 << 23)
157 #define			AT_XDMAC_CC_WRIP_IN_PROGRESS	(0x1 << 23)
158 #define		AT_XDMAC_CC_PERID(i)	(0x7f & (h) << 24)	/* Channel Peripheral Identifier */
159 #define AT_XDMAC_CDS_MSP	0x2C	/* Channel Data Stride Memory Set Pattern */
160 #define AT_XDMAC_CSUS		0x30	/* Channel Source Microblock Stride */
161 #define AT_XDMAC_CDUS		0x34	/* Channel Destination Microblock Stride */
162 
163 #define AT_XDMAC_CHAN_REG_BASE	0x50	/* Channel registers base address */
164 
165 /* Microblock control members */
166 #define AT_XDMAC_MBR_UBC_UBLEN_MAX	0xFFFFFFUL	/* Maximum Microblock Length */
167 #define AT_XDMAC_MBR_UBC_NDE		(0x1 << 24)	/* Next Descriptor Enable */
168 #define AT_XDMAC_MBR_UBC_NSEN		(0x1 << 25)	/* Next Descriptor Source Update */
169 #define AT_XDMAC_MBR_UBC_NDEN		(0x1 << 26)	/* Next Descriptor Destination Update */
170 #define AT_XDMAC_MBR_UBC_NDV0		(0x0 << 27)	/* Next Descriptor View 0 */
171 #define AT_XDMAC_MBR_UBC_NDV1		(0x1 << 27)	/* Next Descriptor View 1 */
172 #define AT_XDMAC_MBR_UBC_NDV2		(0x2 << 27)	/* Next Descriptor View 2 */
173 #define AT_XDMAC_MBR_UBC_NDV3		(0x3 << 27)	/* Next Descriptor View 3 */
174 
175 #define AT_XDMAC_MAX_CHAN	0x20
176 
177 enum atc_status {
178 	AT_XDMAC_CHAN_IS_CYCLIC = 0,
179 	AT_XDMAC_CHAN_IS_PAUSED,
180 };
181 
182 /* ----- Channels ----- */
183 struct at_xdmac_chan {
184 	struct dma_chan			chan;
185 	void __iomem			*ch_regs;
186 	u32				mask;		/* Channel Mask */
187 	u32				cfg[3];		/* Channel Configuration Register */
188 	#define	AT_XDMAC_CUR_CFG	0		/* Current channel conf */
189 	#define	AT_XDMAC_DEV_TO_MEM_CFG	1		/* Predifined dev to mem channel conf */
190 	#define	AT_XDMAC_MEM_TO_DEV_CFG	2		/* Predifined mem to dev channel conf */
191 	u8				perid;		/* Peripheral ID */
192 	u8				perif;		/* Peripheral Interface */
193 	u8				memif;		/* Memory Interface */
194 	u32				per_src_addr;
195 	u32				per_dst_addr;
196 	u32				save_cim;
197 	u32				save_cnda;
198 	u32				save_cndc;
199 	unsigned long			status;
200 	struct tasklet_struct		tasklet;
201 
202 	spinlock_t			lock;
203 
204 	struct list_head		xfers_list;
205 	struct list_head		free_descs_list;
206 };
207 
208 
209 /* ----- Controller ----- */
210 struct at_xdmac {
211 	struct dma_device	dma;
212 	void __iomem		*regs;
213 	int			irq;
214 	struct clk		*clk;
215 	u32			save_gim;
216 	u32			save_gs;
217 	struct dma_pool		*at_xdmac_desc_pool;
218 	struct at_xdmac_chan	chan[0];
219 };
220 
221 
222 /* ----- Descriptors ----- */
223 
224 /* Linked List Descriptor */
225 struct at_xdmac_lld {
226 	dma_addr_t	mbr_nda;	/* Next Descriptor Member */
227 	u32		mbr_ubc;	/* Microblock Control Member */
228 	dma_addr_t	mbr_sa;		/* Source Address Member */
229 	dma_addr_t	mbr_da;		/* Destination Address Member */
230 	u32		mbr_cfg;	/* Configuration Register */
231 };
232 
233 
234 struct at_xdmac_desc {
235 	struct at_xdmac_lld		lld;
236 	enum dma_transfer_direction	direction;
237 	struct dma_async_tx_descriptor	tx_dma_desc;
238 	struct list_head		desc_node;
239 	/* Following members are only used by the first descriptor */
240 	bool				active_xfer;
241 	unsigned int			xfer_size;
242 	struct list_head		descs_list;
243 	struct list_head		xfer_node;
244 };
245 
246 static inline void __iomem *at_xdmac_chan_reg_base(struct at_xdmac *atxdmac, unsigned int chan_nb)
247 {
248 	return atxdmac->regs + (AT_XDMAC_CHAN_REG_BASE + chan_nb * 0x40);
249 }
250 
251 #define at_xdmac_read(atxdmac, reg) readl_relaxed((atxdmac)->regs + (reg))
252 #define at_xdmac_write(atxdmac, reg, value) \
253 	writel_relaxed((value), (atxdmac)->regs + (reg))
254 
255 #define at_xdmac_chan_read(atchan, reg) readl_relaxed((atchan)->ch_regs + (reg))
256 #define at_xdmac_chan_write(atchan, reg, value) writel_relaxed((value), (atchan)->ch_regs + (reg))
257 
258 static inline struct at_xdmac_chan *to_at_xdmac_chan(struct dma_chan *dchan)
259 {
260 	return container_of(dchan, struct at_xdmac_chan, chan);
261 }
262 
263 static struct device *chan2dev(struct dma_chan *chan)
264 {
265 	return &chan->dev->device;
266 }
267 
268 static inline struct at_xdmac *to_at_xdmac(struct dma_device *ddev)
269 {
270 	return container_of(ddev, struct at_xdmac, dma);
271 }
272 
273 static inline struct at_xdmac_desc *txd_to_at_desc(struct dma_async_tx_descriptor *txd)
274 {
275 	return container_of(txd, struct at_xdmac_desc, tx_dma_desc);
276 }
277 
278 static inline int at_xdmac_chan_is_cyclic(struct at_xdmac_chan *atchan)
279 {
280 	return test_bit(AT_XDMAC_CHAN_IS_CYCLIC, &atchan->status);
281 }
282 
283 static inline int at_xdmac_chan_is_paused(struct at_xdmac_chan *atchan)
284 {
285 	return test_bit(AT_XDMAC_CHAN_IS_PAUSED, &atchan->status);
286 }
287 
288 static inline int at_xdmac_csize(u32 maxburst)
289 {
290 	int csize;
291 
292 	csize = ffs(maxburst) - 1;
293 	if (csize > 4)
294 		csize = -EINVAL;
295 
296 	return csize;
297 };
298 
299 static inline u8 at_xdmac_get_dwidth(u32 cfg)
300 {
301 	return (cfg & AT_XDMAC_CC_DWIDTH_MASK) >> AT_XDMAC_CC_DWIDTH_OFFSET;
302 };
303 
304 static unsigned int init_nr_desc_per_channel = 64;
305 module_param(init_nr_desc_per_channel, uint, 0644);
306 MODULE_PARM_DESC(init_nr_desc_per_channel,
307 		 "initial descriptors per channel (default: 64)");
308 
309 
310 static bool at_xdmac_chan_is_enabled(struct at_xdmac_chan *atchan)
311 {
312 	return at_xdmac_chan_read(atchan, AT_XDMAC_GS) & atchan->mask;
313 }
314 
315 static void at_xdmac_off(struct at_xdmac *atxdmac)
316 {
317 	at_xdmac_write(atxdmac, AT_XDMAC_GD, -1L);
318 
319 	/* Wait that all chans are disabled. */
320 	while (at_xdmac_read(atxdmac, AT_XDMAC_GS))
321 		cpu_relax();
322 
323 	at_xdmac_write(atxdmac, AT_XDMAC_GID, -1L);
324 }
325 
326 /* Call with lock hold. */
327 static void at_xdmac_start_xfer(struct at_xdmac_chan *atchan,
328 				struct at_xdmac_desc *first)
329 {
330 	struct at_xdmac	*atxdmac = to_at_xdmac(atchan->chan.device);
331 	u32		reg;
332 
333 	dev_vdbg(chan2dev(&atchan->chan), "%s: desc 0x%p\n", __func__, first);
334 
335 	if (at_xdmac_chan_is_enabled(atchan))
336 		return;
337 
338 	/* Set transfer as active to not try to start it again. */
339 	first->active_xfer = true;
340 
341 	/* Tell xdmac where to get the first descriptor. */
342 	reg = AT_XDMAC_CNDA_NDA(first->tx_dma_desc.phys)
343 	      | AT_XDMAC_CNDA_NDAIF(atchan->memif);
344 	at_xdmac_chan_write(atchan, AT_XDMAC_CNDA, reg);
345 
346 	/*
347 	 * When doing memory to memory transfer we need to use the next
348 	 * descriptor view 2 since some fields of the configuration register
349 	 * depend on transfer size and src/dest addresses.
350 	 */
351 	if (is_slave_direction(first->direction)) {
352 		reg = AT_XDMAC_CNDC_NDVIEW_NDV1;
353 		if (first->direction == DMA_MEM_TO_DEV)
354 			atchan->cfg[AT_XDMAC_CUR_CFG] =
355 				atchan->cfg[AT_XDMAC_MEM_TO_DEV_CFG];
356 		else
357 			atchan->cfg[AT_XDMAC_CUR_CFG] =
358 				atchan->cfg[AT_XDMAC_DEV_TO_MEM_CFG];
359 		at_xdmac_chan_write(atchan, AT_XDMAC_CC,
360 				    atchan->cfg[AT_XDMAC_CUR_CFG]);
361 	} else {
362 		/*
363 		 * No need to write AT_XDMAC_CC reg, it will be done when the
364 		 * descriptor is fecthed.
365 		 */
366 		reg = AT_XDMAC_CNDC_NDVIEW_NDV2;
367 	}
368 
369 	reg |= AT_XDMAC_CNDC_NDDUP
370 	       | AT_XDMAC_CNDC_NDSUP
371 	       | AT_XDMAC_CNDC_NDE;
372 	at_xdmac_chan_write(atchan, AT_XDMAC_CNDC, reg);
373 
374 	dev_vdbg(chan2dev(&atchan->chan),
375 		 "%s: CC=0x%08x CNDA=0x%08x, CNDC=0x%08x, CSA=0x%08x, CDA=0x%08x, CUBC=0x%08x\n",
376 		 __func__, at_xdmac_chan_read(atchan, AT_XDMAC_CC),
377 		 at_xdmac_chan_read(atchan, AT_XDMAC_CNDA),
378 		 at_xdmac_chan_read(atchan, AT_XDMAC_CNDC),
379 		 at_xdmac_chan_read(atchan, AT_XDMAC_CSA),
380 		 at_xdmac_chan_read(atchan, AT_XDMAC_CDA),
381 		 at_xdmac_chan_read(atchan, AT_XDMAC_CUBC));
382 
383 	at_xdmac_chan_write(atchan, AT_XDMAC_CID, 0xffffffff);
384 	reg = AT_XDMAC_CIE_RBEIE | AT_XDMAC_CIE_WBEIE | AT_XDMAC_CIE_ROIE;
385 	/*
386 	 * There is no end of list when doing cyclic dma, we need to get
387 	 * an interrupt after each periods.
388 	 */
389 	if (at_xdmac_chan_is_cyclic(atchan))
390 		at_xdmac_chan_write(atchan, AT_XDMAC_CIE,
391 				    reg | AT_XDMAC_CIE_BIE);
392 	else
393 		at_xdmac_chan_write(atchan, AT_XDMAC_CIE,
394 				    reg | AT_XDMAC_CIE_LIE);
395 	at_xdmac_write(atxdmac, AT_XDMAC_GIE, atchan->mask);
396 	dev_vdbg(chan2dev(&atchan->chan),
397 		 "%s: enable channel (0x%08x)\n", __func__, atchan->mask);
398 	wmb();
399 	at_xdmac_write(atxdmac, AT_XDMAC_GE, atchan->mask);
400 
401 	dev_vdbg(chan2dev(&atchan->chan),
402 		 "%s: CC=0x%08x CNDA=0x%08x, CNDC=0x%08x, CSA=0x%08x, CDA=0x%08x, CUBC=0x%08x\n",
403 		 __func__, at_xdmac_chan_read(atchan, AT_XDMAC_CC),
404 		 at_xdmac_chan_read(atchan, AT_XDMAC_CNDA),
405 		 at_xdmac_chan_read(atchan, AT_XDMAC_CNDC),
406 		 at_xdmac_chan_read(atchan, AT_XDMAC_CSA),
407 		 at_xdmac_chan_read(atchan, AT_XDMAC_CDA),
408 		 at_xdmac_chan_read(atchan, AT_XDMAC_CUBC));
409 
410 }
411 
412 static dma_cookie_t at_xdmac_tx_submit(struct dma_async_tx_descriptor *tx)
413 {
414 	struct at_xdmac_desc	*desc = txd_to_at_desc(tx);
415 	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(tx->chan);
416 	dma_cookie_t		cookie;
417 
418 	spin_lock_bh(&atchan->lock);
419 	cookie = dma_cookie_assign(tx);
420 
421 	dev_vdbg(chan2dev(tx->chan), "%s: atchan 0x%p, add desc 0x%p to xfers_list\n",
422 		 __func__, atchan, desc);
423 	list_add_tail(&desc->xfer_node, &atchan->xfers_list);
424 	if (list_is_singular(&atchan->xfers_list))
425 		at_xdmac_start_xfer(atchan, desc);
426 
427 	spin_unlock_bh(&atchan->lock);
428 	return cookie;
429 }
430 
431 static struct at_xdmac_desc *at_xdmac_alloc_desc(struct dma_chan *chan,
432 						 gfp_t gfp_flags)
433 {
434 	struct at_xdmac_desc	*desc;
435 	struct at_xdmac		*atxdmac = to_at_xdmac(chan->device);
436 	dma_addr_t		phys;
437 
438 	desc = dma_pool_alloc(atxdmac->at_xdmac_desc_pool, gfp_flags, &phys);
439 	if (desc) {
440 		memset(desc, 0, sizeof(*desc));
441 		INIT_LIST_HEAD(&desc->descs_list);
442 		dma_async_tx_descriptor_init(&desc->tx_dma_desc, chan);
443 		desc->tx_dma_desc.tx_submit = at_xdmac_tx_submit;
444 		desc->tx_dma_desc.phys = phys;
445 	}
446 
447 	return desc;
448 }
449 
450 /* Call must be protected by lock. */
451 static struct at_xdmac_desc *at_xdmac_get_desc(struct at_xdmac_chan *atchan)
452 {
453 	struct at_xdmac_desc *desc;
454 
455 	if (list_empty(&atchan->free_descs_list)) {
456 		desc = at_xdmac_alloc_desc(&atchan->chan, GFP_NOWAIT);
457 	} else {
458 		desc = list_first_entry(&atchan->free_descs_list,
459 					struct at_xdmac_desc, desc_node);
460 		list_del(&desc->desc_node);
461 		desc->active_xfer = false;
462 	}
463 
464 	return desc;
465 }
466 
467 static struct dma_chan *at_xdmac_xlate(struct of_phandle_args *dma_spec,
468 				       struct of_dma *of_dma)
469 {
470 	struct at_xdmac		*atxdmac = of_dma->of_dma_data;
471 	struct at_xdmac_chan	*atchan;
472 	struct dma_chan		*chan;
473 	struct device		*dev = atxdmac->dma.dev;
474 
475 	if (dma_spec->args_count != 1) {
476 		dev_err(dev, "dma phandler args: bad number of args\n");
477 		return NULL;
478 	}
479 
480 	chan = dma_get_any_slave_channel(&atxdmac->dma);
481 	if (!chan) {
482 		dev_err(dev, "can't get a dma channel\n");
483 		return NULL;
484 	}
485 
486 	atchan = to_at_xdmac_chan(chan);
487 	atchan->memif = AT91_XDMAC_DT_GET_MEM_IF(dma_spec->args[0]);
488 	atchan->perif = AT91_XDMAC_DT_GET_PER_IF(dma_spec->args[0]);
489 	atchan->perid = AT91_XDMAC_DT_GET_PERID(dma_spec->args[0]);
490 	dev_dbg(dev, "chan dt cfg: memif=%u perif=%u perid=%u\n",
491 		 atchan->memif, atchan->perif, atchan->perid);
492 
493 	return chan;
494 }
495 
496 static int at_xdmac_set_slave_config(struct dma_chan *chan,
497 				      struct dma_slave_config *sconfig)
498 {
499 	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
500 	u8 dwidth;
501 	int csize;
502 
503 	atchan->cfg[AT_XDMAC_DEV_TO_MEM_CFG] =
504 		AT91_XDMAC_DT_PERID(atchan->perid)
505 		| AT_XDMAC_CC_DAM_INCREMENTED_AM
506 		| AT_XDMAC_CC_SAM_FIXED_AM
507 		| AT_XDMAC_CC_DIF(atchan->memif)
508 		| AT_XDMAC_CC_SIF(atchan->perif)
509 		| AT_XDMAC_CC_SWREQ_HWR_CONNECTED
510 		| AT_XDMAC_CC_DSYNC_PER2MEM
511 		| AT_XDMAC_CC_MBSIZE_SIXTEEN
512 		| AT_XDMAC_CC_TYPE_PER_TRAN;
513 	csize = at_xdmac_csize(sconfig->src_maxburst);
514 	if (csize < 0) {
515 		dev_err(chan2dev(chan), "invalid src maxburst value\n");
516 		return -EINVAL;
517 	}
518 	atchan->cfg[AT_XDMAC_DEV_TO_MEM_CFG] |= AT_XDMAC_CC_CSIZE(csize);
519 	dwidth = ffs(sconfig->src_addr_width) - 1;
520 	atchan->cfg[AT_XDMAC_DEV_TO_MEM_CFG] |= AT_XDMAC_CC_DWIDTH(dwidth);
521 
522 
523 	atchan->cfg[AT_XDMAC_MEM_TO_DEV_CFG] =
524 		AT91_XDMAC_DT_PERID(atchan->perid)
525 		| AT_XDMAC_CC_DAM_FIXED_AM
526 		| AT_XDMAC_CC_SAM_INCREMENTED_AM
527 		| AT_XDMAC_CC_DIF(atchan->perif)
528 		| AT_XDMAC_CC_SIF(atchan->memif)
529 		| AT_XDMAC_CC_SWREQ_HWR_CONNECTED
530 		| AT_XDMAC_CC_DSYNC_MEM2PER
531 		| AT_XDMAC_CC_MBSIZE_SIXTEEN
532 		| AT_XDMAC_CC_TYPE_PER_TRAN;
533 	csize = at_xdmac_csize(sconfig->dst_maxburst);
534 	if (csize < 0) {
535 		dev_err(chan2dev(chan), "invalid src maxburst value\n");
536 		return -EINVAL;
537 	}
538 	atchan->cfg[AT_XDMAC_MEM_TO_DEV_CFG] |= AT_XDMAC_CC_CSIZE(csize);
539 	dwidth = ffs(sconfig->dst_addr_width) - 1;
540 	atchan->cfg[AT_XDMAC_MEM_TO_DEV_CFG] |= AT_XDMAC_CC_DWIDTH(dwidth);
541 
542 	/* Src and dst addr are needed to configure the link list descriptor. */
543 	atchan->per_src_addr = sconfig->src_addr;
544 	atchan->per_dst_addr = sconfig->dst_addr;
545 
546 	dev_dbg(chan2dev(chan),
547 		"%s: cfg[dev2mem]=0x%08x, cfg[mem2dev]=0x%08x, per_src_addr=0x%08x, per_dst_addr=0x%08x\n",
548 		__func__, atchan->cfg[AT_XDMAC_DEV_TO_MEM_CFG],
549 		atchan->cfg[AT_XDMAC_MEM_TO_DEV_CFG],
550 		atchan->per_src_addr, atchan->per_dst_addr);
551 
552 	return 0;
553 }
554 
555 static struct dma_async_tx_descriptor *
556 at_xdmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
557 		       unsigned int sg_len, enum dma_transfer_direction direction,
558 		       unsigned long flags, void *context)
559 {
560 	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
561 	struct at_xdmac_desc	*first = NULL, *prev = NULL;
562 	struct scatterlist	*sg;
563 	int			i;
564 	u32			cfg;
565 	unsigned int		xfer_size = 0;
566 
567 	if (!sgl)
568 		return NULL;
569 
570 	if (!is_slave_direction(direction)) {
571 		dev_err(chan2dev(chan), "invalid DMA direction\n");
572 		return NULL;
573 	}
574 
575 	dev_dbg(chan2dev(chan), "%s: sg_len=%d, dir=%s, flags=0x%lx\n",
576 		 __func__, sg_len,
577 		 direction == DMA_MEM_TO_DEV ? "to device" : "from device",
578 		 flags);
579 
580 	/* Protect dma_sconfig field that can be modified by set_slave_conf. */
581 	spin_lock_bh(&atchan->lock);
582 
583 	/* Prepare descriptors. */
584 	for_each_sg(sgl, sg, sg_len, i) {
585 		struct at_xdmac_desc	*desc = NULL;
586 		u32			len, mem;
587 
588 		len = sg_dma_len(sg);
589 		mem = sg_dma_address(sg);
590 		if (unlikely(!len)) {
591 			dev_err(chan2dev(chan), "sg data length is zero\n");
592 			spin_unlock_bh(&atchan->lock);
593 			return NULL;
594 		}
595 		dev_dbg(chan2dev(chan), "%s: * sg%d len=%u, mem=0x%08x\n",
596 			 __func__, i, len, mem);
597 
598 		desc = at_xdmac_get_desc(atchan);
599 		if (!desc) {
600 			dev_err(chan2dev(chan), "can't get descriptor\n");
601 			if (first)
602 				list_splice_init(&first->descs_list, &atchan->free_descs_list);
603 			spin_unlock_bh(&atchan->lock);
604 			return NULL;
605 		}
606 
607 		/* Linked list descriptor setup. */
608 		if (direction == DMA_DEV_TO_MEM) {
609 			desc->lld.mbr_sa = atchan->per_src_addr;
610 			desc->lld.mbr_da = mem;
611 			cfg = atchan->cfg[AT_XDMAC_DEV_TO_MEM_CFG];
612 		} else {
613 			desc->lld.mbr_sa = mem;
614 			desc->lld.mbr_da = atchan->per_dst_addr;
615 			cfg = atchan->cfg[AT_XDMAC_MEM_TO_DEV_CFG];
616 		}
617 		desc->lld.mbr_ubc = AT_XDMAC_MBR_UBC_NDV1		/* next descriptor view */
618 			| AT_XDMAC_MBR_UBC_NDEN				/* next descriptor dst parameter update */
619 			| AT_XDMAC_MBR_UBC_NSEN				/* next descriptor src parameter update */
620 			| (i == sg_len - 1 ? 0 : AT_XDMAC_MBR_UBC_NDE)	/* descriptor fetch */
621 			| len / (1 << at_xdmac_get_dwidth(cfg));	/* microblock length */
622 		dev_dbg(chan2dev(chan),
623 			 "%s: lld: mbr_sa=%pad, mbr_da=%pad, mbr_ubc=0x%08x\n",
624 			 __func__, &desc->lld.mbr_sa, &desc->lld.mbr_da, desc->lld.mbr_ubc);
625 
626 		/* Chain lld. */
627 		if (prev) {
628 			prev->lld.mbr_nda = desc->tx_dma_desc.phys;
629 			dev_dbg(chan2dev(chan),
630 				 "%s: chain lld: prev=0x%p, mbr_nda=%pad\n",
631 				 __func__, prev, &prev->lld.mbr_nda);
632 		}
633 
634 		prev = desc;
635 		if (!first)
636 			first = desc;
637 
638 		dev_dbg(chan2dev(chan), "%s: add desc 0x%p to descs_list 0x%p\n",
639 			 __func__, desc, first);
640 		list_add_tail(&desc->desc_node, &first->descs_list);
641 		xfer_size += len;
642 	}
643 
644 	spin_unlock_bh(&atchan->lock);
645 
646 	first->tx_dma_desc.flags = flags;
647 	first->xfer_size = xfer_size;
648 	first->direction = direction;
649 
650 	return &first->tx_dma_desc;
651 }
652 
653 static struct dma_async_tx_descriptor *
654 at_xdmac_prep_dma_cyclic(struct dma_chan *chan, dma_addr_t buf_addr,
655 			 size_t buf_len, size_t period_len,
656 			 enum dma_transfer_direction direction,
657 			 unsigned long flags)
658 {
659 	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
660 	struct at_xdmac_desc	*first = NULL, *prev = NULL;
661 	unsigned int		periods = buf_len / period_len;
662 	int			i;
663 	u32			cfg;
664 
665 	dev_dbg(chan2dev(chan), "%s: buf_addr=%pad, buf_len=%zd, period_len=%zd, dir=%s, flags=0x%lx\n",
666 		__func__, &buf_addr, buf_len, period_len,
667 		direction == DMA_MEM_TO_DEV ? "mem2per" : "per2mem", flags);
668 
669 	if (!is_slave_direction(direction)) {
670 		dev_err(chan2dev(chan), "invalid DMA direction\n");
671 		return NULL;
672 	}
673 
674 	if (test_and_set_bit(AT_XDMAC_CHAN_IS_CYCLIC, &atchan->status)) {
675 		dev_err(chan2dev(chan), "channel currently used\n");
676 		return NULL;
677 	}
678 
679 	for (i = 0; i < periods; i++) {
680 		struct at_xdmac_desc	*desc = NULL;
681 
682 		spin_lock_bh(&atchan->lock);
683 		desc = at_xdmac_get_desc(atchan);
684 		if (!desc) {
685 			dev_err(chan2dev(chan), "can't get descriptor\n");
686 			if (first)
687 				list_splice_init(&first->descs_list, &atchan->free_descs_list);
688 			spin_unlock_bh(&atchan->lock);
689 			return NULL;
690 		}
691 		spin_unlock_bh(&atchan->lock);
692 		dev_dbg(chan2dev(chan),
693 			"%s: desc=0x%p, tx_dma_desc.phys=%pad\n",
694 			__func__, desc, &desc->tx_dma_desc.phys);
695 
696 		if (direction == DMA_DEV_TO_MEM) {
697 			desc->lld.mbr_sa = atchan->per_src_addr;
698 			desc->lld.mbr_da = buf_addr + i * period_len;
699 			cfg = atchan->cfg[AT_XDMAC_DEV_TO_MEM_CFG];
700 		} else {
701 			desc->lld.mbr_sa = buf_addr + i * period_len;
702 			desc->lld.mbr_da = atchan->per_dst_addr;
703 			cfg = atchan->cfg[AT_XDMAC_MEM_TO_DEV_CFG];
704 		}
705 		desc->lld.mbr_ubc = AT_XDMAC_MBR_UBC_NDV1
706 			| AT_XDMAC_MBR_UBC_NDEN
707 			| AT_XDMAC_MBR_UBC_NSEN
708 			| AT_XDMAC_MBR_UBC_NDE
709 			| period_len >> at_xdmac_get_dwidth(cfg);
710 
711 		dev_dbg(chan2dev(chan),
712 			 "%s: lld: mbr_sa=%pad, mbr_da=%pad, mbr_ubc=0x%08x\n",
713 			 __func__, &desc->lld.mbr_sa, &desc->lld.mbr_da, desc->lld.mbr_ubc);
714 
715 		/* Chain lld. */
716 		if (prev) {
717 			prev->lld.mbr_nda = desc->tx_dma_desc.phys;
718 			dev_dbg(chan2dev(chan),
719 				 "%s: chain lld: prev=0x%p, mbr_nda=%pad\n",
720 				 __func__, prev, &prev->lld.mbr_nda);
721 		}
722 
723 		prev = desc;
724 		if (!first)
725 			first = desc;
726 
727 		dev_dbg(chan2dev(chan), "%s: add desc 0x%p to descs_list 0x%p\n",
728 			 __func__, desc, first);
729 		list_add_tail(&desc->desc_node, &first->descs_list);
730 	}
731 
732 	prev->lld.mbr_nda = first->tx_dma_desc.phys;
733 	dev_dbg(chan2dev(chan),
734 		"%s: chain lld: prev=0x%p, mbr_nda=%pad\n",
735 		__func__, prev, &prev->lld.mbr_nda);
736 	first->tx_dma_desc.flags = flags;
737 	first->xfer_size = buf_len;
738 	first->direction = direction;
739 
740 	return &first->tx_dma_desc;
741 }
742 
743 static struct dma_async_tx_descriptor *
744 at_xdmac_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
745 			 size_t len, unsigned long flags)
746 {
747 	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
748 	struct at_xdmac_desc	*first = NULL, *prev = NULL;
749 	size_t			remaining_size = len, xfer_size = 0, ublen;
750 	dma_addr_t		src_addr = src, dst_addr = dest;
751 	u32			dwidth;
752 	/*
753 	 * WARNING: We don't know the direction, it involves we can't
754 	 * dynamically set the source and dest interface so we have to use the
755 	 * same one. Only interface 0 allows EBI access. Hopefully we can
756 	 * access DDR through both ports (at least on SAMA5D4x), so we can use
757 	 * the same interface for source and dest, that solves the fact we
758 	 * don't know the direction.
759 	 */
760 	u32			chan_cc = AT_XDMAC_CC_DAM_INCREMENTED_AM
761 					| AT_XDMAC_CC_SAM_INCREMENTED_AM
762 					| AT_XDMAC_CC_DIF(0)
763 					| AT_XDMAC_CC_SIF(0)
764 					| AT_XDMAC_CC_MBSIZE_SIXTEEN
765 					| AT_XDMAC_CC_TYPE_MEM_TRAN;
766 
767 	dev_dbg(chan2dev(chan), "%s: src=%pad, dest=%pad, len=%zd, flags=0x%lx\n",
768 		__func__, &src, &dest, len, flags);
769 
770 	if (unlikely(!len))
771 		return NULL;
772 
773 	/*
774 	 * Check address alignment to select the greater data width we can use.
775 	 * Some XDMAC implementations don't provide dword transfer, in this
776 	 * case selecting dword has the same behavior as selecting word transfers.
777 	 */
778 	if (!((src_addr | dst_addr) & 7)) {
779 		dwidth = AT_XDMAC_CC_DWIDTH_DWORD;
780 		dev_dbg(chan2dev(chan), "%s: dwidth: double word\n", __func__);
781 	} else if (!((src_addr | dst_addr)  & 3)) {
782 		dwidth = AT_XDMAC_CC_DWIDTH_WORD;
783 		dev_dbg(chan2dev(chan), "%s: dwidth: word\n", __func__);
784 	} else if (!((src_addr | dst_addr) & 1)) {
785 		dwidth = AT_XDMAC_CC_DWIDTH_HALFWORD;
786 		dev_dbg(chan2dev(chan), "%s: dwidth: half word\n", __func__);
787 	} else {
788 		dwidth = AT_XDMAC_CC_DWIDTH_BYTE;
789 		dev_dbg(chan2dev(chan), "%s: dwidth: byte\n", __func__);
790 	}
791 
792 	/* Prepare descriptors. */
793 	while (remaining_size) {
794 		struct at_xdmac_desc	*desc = NULL;
795 
796 		dev_dbg(chan2dev(chan), "%s: remaining_size=%zu\n", __func__, remaining_size);
797 
798 		spin_lock_bh(&atchan->lock);
799 		desc = at_xdmac_get_desc(atchan);
800 		spin_unlock_bh(&atchan->lock);
801 		if (!desc) {
802 			dev_err(chan2dev(chan), "can't get descriptor\n");
803 			if (first)
804 				list_splice_init(&first->descs_list, &atchan->free_descs_list);
805 			return NULL;
806 		}
807 
808 		/* Update src and dest addresses. */
809 		src_addr += xfer_size;
810 		dst_addr += xfer_size;
811 
812 		if (remaining_size >= AT_XDMAC_MBR_UBC_UBLEN_MAX << dwidth)
813 			xfer_size = AT_XDMAC_MBR_UBC_UBLEN_MAX << dwidth;
814 		else
815 			xfer_size = remaining_size;
816 
817 		dev_dbg(chan2dev(chan), "%s: xfer_size=%zu\n", __func__, xfer_size);
818 
819 		/* Check remaining length and change data width if needed. */
820 		if (!((src_addr | dst_addr | xfer_size) & 7)) {
821 			dwidth = AT_XDMAC_CC_DWIDTH_DWORD;
822 			dev_dbg(chan2dev(chan), "%s: dwidth: double word\n", __func__);
823 		} else if (!((src_addr | dst_addr | xfer_size)  & 3)) {
824 			dwidth = AT_XDMAC_CC_DWIDTH_WORD;
825 			dev_dbg(chan2dev(chan), "%s: dwidth: word\n", __func__);
826 		} else if (!((src_addr | dst_addr | xfer_size) & 1)) {
827 			dwidth = AT_XDMAC_CC_DWIDTH_HALFWORD;
828 			dev_dbg(chan2dev(chan), "%s: dwidth: half word\n", __func__);
829 		} else if ((src_addr | dst_addr | xfer_size) & 1) {
830 			dwidth = AT_XDMAC_CC_DWIDTH_BYTE;
831 			dev_dbg(chan2dev(chan), "%s: dwidth: byte\n", __func__);
832 		}
833 		chan_cc |= AT_XDMAC_CC_DWIDTH(dwidth);
834 
835 		ublen = xfer_size >> dwidth;
836 		remaining_size -= xfer_size;
837 
838 		desc->lld.mbr_sa = src_addr;
839 		desc->lld.mbr_da = dst_addr;
840 		desc->lld.mbr_ubc = AT_XDMAC_MBR_UBC_NDV2
841 			| AT_XDMAC_MBR_UBC_NDEN
842 			| AT_XDMAC_MBR_UBC_NSEN
843 			| (remaining_size ? AT_XDMAC_MBR_UBC_NDE : 0)
844 			| ublen;
845 		desc->lld.mbr_cfg = chan_cc;
846 
847 		dev_dbg(chan2dev(chan),
848 			 "%s: lld: mbr_sa=%pad, mbr_da=%pad, mbr_ubc=0x%08x, mbr_cfg=0x%08x\n",
849 			 __func__, &desc->lld.mbr_sa, &desc->lld.mbr_da, desc->lld.mbr_ubc, desc->lld.mbr_cfg);
850 
851 		/* Chain lld. */
852 		if (prev) {
853 			prev->lld.mbr_nda = desc->tx_dma_desc.phys;
854 			dev_dbg(chan2dev(chan),
855 				 "%s: chain lld: prev=0x%p, mbr_nda=0x%08x\n",
856 				 __func__, prev, prev->lld.mbr_nda);
857 		}
858 
859 		prev = desc;
860 		if (!first)
861 			first = desc;
862 
863 		dev_dbg(chan2dev(chan), "%s: add desc 0x%p to descs_list 0x%p\n",
864 			 __func__, desc, first);
865 		list_add_tail(&desc->desc_node, &first->descs_list);
866 	}
867 
868 	first->tx_dma_desc.flags = flags;
869 	first->xfer_size = len;
870 
871 	return &first->tx_dma_desc;
872 }
873 
874 static enum dma_status
875 at_xdmac_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
876 		struct dma_tx_state *txstate)
877 {
878 	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
879 	struct at_xdmac		*atxdmac = to_at_xdmac(atchan->chan.device);
880 	struct at_xdmac_desc	*desc, *_desc;
881 	struct list_head	*descs_list;
882 	enum dma_status		ret;
883 	int			residue;
884 	u32			cur_nda, mask, value;
885 	u8			dwidth = at_xdmac_get_dwidth(atchan->cfg[AT_XDMAC_CUR_CFG]);
886 
887 	ret = dma_cookie_status(chan, cookie, txstate);
888 	if (ret == DMA_COMPLETE)
889 		return ret;
890 
891 	if (!txstate)
892 		return ret;
893 
894 	spin_lock_bh(&atchan->lock);
895 
896 	desc = list_first_entry(&atchan->xfers_list, struct at_xdmac_desc, xfer_node);
897 
898 	/*
899 	 * If the transfer has not been started yet, don't need to compute the
900 	 * residue, it's the transfer length.
901 	 */
902 	if (!desc->active_xfer) {
903 		dma_set_residue(txstate, desc->xfer_size);
904 		spin_unlock_bh(&atchan->lock);
905 		return ret;
906 	}
907 
908 	residue = desc->xfer_size;
909 	/*
910 	 * Flush FIFO: only relevant when the transfer is source peripheral
911 	 * synchronized.
912 	 */
913 	mask = AT_XDMAC_CC_TYPE | AT_XDMAC_CC_DSYNC;
914 	value = AT_XDMAC_CC_TYPE_PER_TRAN | AT_XDMAC_CC_DSYNC_PER2MEM;
915 	if ((atchan->cfg[AT_XDMAC_CUR_CFG] & mask) == value) {
916 		at_xdmac_write(atxdmac, AT_XDMAC_GSWF, atchan->mask);
917 		while (!(at_xdmac_chan_read(atchan, AT_XDMAC_CIS) & AT_XDMAC_CIS_FIS))
918 			cpu_relax();
919 	}
920 
921 	cur_nda = at_xdmac_chan_read(atchan, AT_XDMAC_CNDA) & 0xfffffffc;
922 	/*
923 	 * Remove size of all microblocks already transferred and the current
924 	 * one. Then add the remaining size to transfer of the current
925 	 * microblock.
926 	 */
927 	descs_list = &desc->descs_list;
928 	list_for_each_entry_safe(desc, _desc, descs_list, desc_node) {
929 		residue -= (desc->lld.mbr_ubc & 0xffffff) << dwidth;
930 		if ((desc->lld.mbr_nda & 0xfffffffc) == cur_nda)
931 			break;
932 	}
933 	residue += at_xdmac_chan_read(atchan, AT_XDMAC_CUBC) << dwidth;
934 
935 	spin_unlock_bh(&atchan->lock);
936 
937 	dma_set_residue(txstate, residue);
938 
939 	dev_dbg(chan2dev(chan),
940 		 "%s: desc=0x%p, tx_dma_desc.phys=%pad, tx_status=%d, cookie=%d, residue=%d\n",
941 		 __func__, desc, &desc->tx_dma_desc.phys, ret, cookie, residue);
942 
943 	return ret;
944 }
945 
946 /* Call must be protected by lock. */
947 static void at_xdmac_remove_xfer(struct at_xdmac_chan *atchan,
948 				    struct at_xdmac_desc *desc)
949 {
950 	dev_dbg(chan2dev(&atchan->chan), "%s: desc 0x%p\n", __func__, desc);
951 
952 	/*
953 	 * Remove the transfer from the transfer list then move the transfer
954 	 * descriptors into the free descriptors list.
955 	 */
956 	list_del(&desc->xfer_node);
957 	list_splice_init(&desc->descs_list, &atchan->free_descs_list);
958 }
959 
960 static void at_xdmac_advance_work(struct at_xdmac_chan *atchan)
961 {
962 	struct at_xdmac_desc	*desc;
963 
964 	spin_lock_bh(&atchan->lock);
965 
966 	/*
967 	 * If channel is enabled, do nothing, advance_work will be triggered
968 	 * after the interruption.
969 	 */
970 	if (!at_xdmac_chan_is_enabled(atchan) && !list_empty(&atchan->xfers_list)) {
971 		desc = list_first_entry(&atchan->xfers_list,
972 					struct at_xdmac_desc,
973 					xfer_node);
974 		dev_vdbg(chan2dev(&atchan->chan), "%s: desc 0x%p\n", __func__, desc);
975 		if (!desc->active_xfer)
976 			at_xdmac_start_xfer(atchan, desc);
977 	}
978 
979 	spin_unlock_bh(&atchan->lock);
980 }
981 
982 static void at_xdmac_handle_cyclic(struct at_xdmac_chan *atchan)
983 {
984 	struct at_xdmac_desc		*desc;
985 	struct dma_async_tx_descriptor	*txd;
986 
987 	desc = list_first_entry(&atchan->xfers_list, struct at_xdmac_desc, xfer_node);
988 	txd = &desc->tx_dma_desc;
989 
990 	if (txd->callback && (txd->flags & DMA_PREP_INTERRUPT))
991 		txd->callback(txd->callback_param);
992 }
993 
994 static void at_xdmac_tasklet(unsigned long data)
995 {
996 	struct at_xdmac_chan	*atchan = (struct at_xdmac_chan *)data;
997 	struct at_xdmac_desc	*desc;
998 	u32			error_mask;
999 
1000 	dev_dbg(chan2dev(&atchan->chan), "%s: status=0x%08lx\n",
1001 		 __func__, atchan->status);
1002 
1003 	error_mask = AT_XDMAC_CIS_RBEIS
1004 		     | AT_XDMAC_CIS_WBEIS
1005 		     | AT_XDMAC_CIS_ROIS;
1006 
1007 	if (at_xdmac_chan_is_cyclic(atchan)) {
1008 		at_xdmac_handle_cyclic(atchan);
1009 	} else if ((atchan->status & AT_XDMAC_CIS_LIS)
1010 		   || (atchan->status & error_mask)) {
1011 		struct dma_async_tx_descriptor  *txd;
1012 
1013 		if (atchan->status & AT_XDMAC_CIS_RBEIS)
1014 			dev_err(chan2dev(&atchan->chan), "read bus error!!!");
1015 		if (atchan->status & AT_XDMAC_CIS_WBEIS)
1016 			dev_err(chan2dev(&atchan->chan), "write bus error!!!");
1017 		if (atchan->status & AT_XDMAC_CIS_ROIS)
1018 			dev_err(chan2dev(&atchan->chan), "request overflow error!!!");
1019 
1020 		spin_lock_bh(&atchan->lock);
1021 		desc = list_first_entry(&atchan->xfers_list,
1022 					struct at_xdmac_desc,
1023 					xfer_node);
1024 		dev_vdbg(chan2dev(&atchan->chan), "%s: desc 0x%p\n", __func__, desc);
1025 		BUG_ON(!desc->active_xfer);
1026 
1027 		txd = &desc->tx_dma_desc;
1028 
1029 		at_xdmac_remove_xfer(atchan, desc);
1030 		spin_unlock_bh(&atchan->lock);
1031 
1032 		if (!at_xdmac_chan_is_cyclic(atchan)) {
1033 			dma_cookie_complete(txd);
1034 			if (txd->callback && (txd->flags & DMA_PREP_INTERRUPT))
1035 				txd->callback(txd->callback_param);
1036 		}
1037 
1038 		dma_run_dependencies(txd);
1039 
1040 		at_xdmac_advance_work(atchan);
1041 	}
1042 }
1043 
1044 static irqreturn_t at_xdmac_interrupt(int irq, void *dev_id)
1045 {
1046 	struct at_xdmac		*atxdmac = (struct at_xdmac *)dev_id;
1047 	struct at_xdmac_chan	*atchan;
1048 	u32			imr, status, pending;
1049 	u32			chan_imr, chan_status;
1050 	int			i, ret = IRQ_NONE;
1051 
1052 	do {
1053 		imr = at_xdmac_read(atxdmac, AT_XDMAC_GIM);
1054 		status = at_xdmac_read(atxdmac, AT_XDMAC_GIS);
1055 		pending = status & imr;
1056 
1057 		dev_vdbg(atxdmac->dma.dev,
1058 			 "%s: status=0x%08x, imr=0x%08x, pending=0x%08x\n",
1059 			 __func__, status, imr, pending);
1060 
1061 		if (!pending)
1062 			break;
1063 
1064 		/* We have to find which channel has generated the interrupt. */
1065 		for (i = 0; i < atxdmac->dma.chancnt; i++) {
1066 			if (!((1 << i) & pending))
1067 				continue;
1068 
1069 			atchan = &atxdmac->chan[i];
1070 			chan_imr = at_xdmac_chan_read(atchan, AT_XDMAC_CIM);
1071 			chan_status = at_xdmac_chan_read(atchan, AT_XDMAC_CIS);
1072 			atchan->status = chan_status & chan_imr;
1073 			dev_vdbg(atxdmac->dma.dev,
1074 				 "%s: chan%d: imr=0x%x, status=0x%x\n",
1075 				 __func__, i, chan_imr, chan_status);
1076 			dev_vdbg(chan2dev(&atchan->chan),
1077 				 "%s: CC=0x%08x CNDA=0x%08x, CNDC=0x%08x, CSA=0x%08x, CDA=0x%08x, CUBC=0x%08x\n",
1078 				 __func__,
1079 				 at_xdmac_chan_read(atchan, AT_XDMAC_CC),
1080 				 at_xdmac_chan_read(atchan, AT_XDMAC_CNDA),
1081 				 at_xdmac_chan_read(atchan, AT_XDMAC_CNDC),
1082 				 at_xdmac_chan_read(atchan, AT_XDMAC_CSA),
1083 				 at_xdmac_chan_read(atchan, AT_XDMAC_CDA),
1084 				 at_xdmac_chan_read(atchan, AT_XDMAC_CUBC));
1085 
1086 			if (atchan->status & (AT_XDMAC_CIS_RBEIS | AT_XDMAC_CIS_WBEIS))
1087 				at_xdmac_write(atxdmac, AT_XDMAC_GD, atchan->mask);
1088 
1089 			tasklet_schedule(&atchan->tasklet);
1090 			ret = IRQ_HANDLED;
1091 		}
1092 
1093 	} while (pending);
1094 
1095 	return ret;
1096 }
1097 
1098 static void at_xdmac_issue_pending(struct dma_chan *chan)
1099 {
1100 	struct at_xdmac_chan *atchan = to_at_xdmac_chan(chan);
1101 
1102 	dev_dbg(chan2dev(&atchan->chan), "%s\n", __func__);
1103 
1104 	if (!at_xdmac_chan_is_cyclic(atchan))
1105 		at_xdmac_advance_work(atchan);
1106 
1107 	return;
1108 }
1109 
1110 static int at_xdmac_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
1111 			    unsigned long arg)
1112 {
1113 	struct at_xdmac_desc	*desc, *_desc;
1114 	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
1115 	struct at_xdmac		*atxdmac = to_at_xdmac(atchan->chan.device);
1116 	int			ret = 0;
1117 
1118 	dev_dbg(chan2dev(chan), "%s: cmd=%d\n", __func__, cmd);
1119 
1120 	spin_lock_bh(&atchan->lock);
1121 
1122 	switch (cmd) {
1123 	case DMA_PAUSE:
1124 		at_xdmac_write(atxdmac, AT_XDMAC_GRWS, atchan->mask);
1125 		set_bit(AT_XDMAC_CHAN_IS_PAUSED, &atchan->status);
1126 		break;
1127 
1128 	case DMA_RESUME:
1129 		if (!at_xdmac_chan_is_paused(atchan))
1130 			break;
1131 
1132 		at_xdmac_write(atxdmac, AT_XDMAC_GRWR, atchan->mask);
1133 		clear_bit(AT_XDMAC_CHAN_IS_PAUSED, &atchan->status);
1134 		break;
1135 
1136 	case DMA_TERMINATE_ALL:
1137 		at_xdmac_write(atxdmac, AT_XDMAC_GD, atchan->mask);
1138 		while (at_xdmac_read(atxdmac, AT_XDMAC_GS) & atchan->mask)
1139 			cpu_relax();
1140 
1141 		/* Cancel all pending transfers. */
1142 		list_for_each_entry_safe(desc, _desc, &atchan->xfers_list, xfer_node)
1143 			at_xdmac_remove_xfer(atchan, desc);
1144 
1145 		clear_bit(AT_XDMAC_CHAN_IS_CYCLIC, &atchan->status);
1146 		break;
1147 
1148 	case DMA_SLAVE_CONFIG:
1149 		ret = at_xdmac_set_slave_config(chan,
1150 				(struct dma_slave_config *)arg);
1151 		break;
1152 
1153 	default:
1154 		dev_err(chan2dev(chan),
1155 			"unmanaged or unknown dma control cmd: %d\n", cmd);
1156 		ret = -ENXIO;
1157 	}
1158 
1159 	spin_unlock_bh(&atchan->lock);
1160 
1161 	return ret;
1162 }
1163 
1164 static int at_xdmac_alloc_chan_resources(struct dma_chan *chan)
1165 {
1166 	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
1167 	struct at_xdmac_desc	*desc;
1168 	int			i;
1169 
1170 	spin_lock_bh(&atchan->lock);
1171 
1172 	if (at_xdmac_chan_is_enabled(atchan)) {
1173 		dev_err(chan2dev(chan),
1174 			"can't allocate channel resources (channel enabled)\n");
1175 		i = -EIO;
1176 		goto spin_unlock;
1177 	}
1178 
1179 	if (!list_empty(&atchan->free_descs_list)) {
1180 		dev_err(chan2dev(chan),
1181 			"can't allocate channel resources (channel not free from a previous use)\n");
1182 		i = -EIO;
1183 		goto spin_unlock;
1184 	}
1185 
1186 	for (i = 0; i < init_nr_desc_per_channel; i++) {
1187 		desc = at_xdmac_alloc_desc(chan, GFP_ATOMIC);
1188 		if (!desc) {
1189 			dev_warn(chan2dev(chan),
1190 				"only %d descriptors have been allocated\n", i);
1191 			break;
1192 		}
1193 		list_add_tail(&desc->desc_node, &atchan->free_descs_list);
1194 	}
1195 
1196 	dma_cookie_init(chan);
1197 
1198 	dev_dbg(chan2dev(chan), "%s: allocated %d descriptors\n", __func__, i);
1199 
1200 spin_unlock:
1201 	spin_unlock_bh(&atchan->lock);
1202 	return i;
1203 }
1204 
1205 static void at_xdmac_free_chan_resources(struct dma_chan *chan)
1206 {
1207 	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
1208 	struct at_xdmac		*atxdmac = to_at_xdmac(chan->device);
1209 	struct at_xdmac_desc	*desc, *_desc;
1210 
1211 	list_for_each_entry_safe(desc, _desc, &atchan->free_descs_list, desc_node) {
1212 		dev_dbg(chan2dev(chan), "%s: freeing descriptor %p\n", __func__, desc);
1213 		list_del(&desc->desc_node);
1214 		dma_pool_free(atxdmac->at_xdmac_desc_pool, desc, desc->tx_dma_desc.phys);
1215 	}
1216 
1217 	return;
1218 }
1219 
1220 #define AT_XDMAC_DMA_BUSWIDTHS\
1221 	(BIT(DMA_SLAVE_BUSWIDTH_UNDEFINED) |\
1222 	BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |\
1223 	BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |\
1224 	BIT(DMA_SLAVE_BUSWIDTH_4_BYTES) |\
1225 	BIT(DMA_SLAVE_BUSWIDTH_8_BYTES))
1226 
1227 static int at_xdmac_device_slave_caps(struct dma_chan *dchan,
1228 				      struct dma_slave_caps *caps)
1229 {
1230 
1231 	caps->src_addr_widths = AT_XDMAC_DMA_BUSWIDTHS;
1232 	caps->dstn_addr_widths = AT_XDMAC_DMA_BUSWIDTHS;
1233 	caps->directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
1234 	caps->cmd_pause = true;
1235 	caps->cmd_terminate = true;
1236 	caps->residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
1237 
1238 	return 0;
1239 }
1240 
1241 #ifdef CONFIG_PM
1242 static int atmel_xdmac_prepare(struct device *dev)
1243 {
1244 	struct platform_device	*pdev = to_platform_device(dev);
1245 	struct at_xdmac		*atxdmac = platform_get_drvdata(pdev);
1246 	struct dma_chan		*chan, *_chan;
1247 
1248 	list_for_each_entry_safe(chan, _chan, &atxdmac->dma.channels, device_node) {
1249 		struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
1250 
1251 		/* Wait for transfer completion, except in cyclic case. */
1252 		if (at_xdmac_chan_is_enabled(atchan) && !at_xdmac_chan_is_cyclic(atchan))
1253 			return -EAGAIN;
1254 	}
1255 	return 0;
1256 }
1257 #else
1258 #	define atmel_xdmac_prepare NULL
1259 #endif
1260 
1261 #ifdef CONFIG_PM_SLEEP
1262 static int atmel_xdmac_suspend(struct device *dev)
1263 {
1264 	struct platform_device	*pdev = to_platform_device(dev);
1265 	struct at_xdmac		*atxdmac = platform_get_drvdata(pdev);
1266 	struct dma_chan		*chan, *_chan;
1267 
1268 	list_for_each_entry_safe(chan, _chan, &atxdmac->dma.channels, device_node) {
1269 		struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
1270 
1271 		if (at_xdmac_chan_is_cyclic(atchan)) {
1272 			if (!at_xdmac_chan_is_paused(atchan))
1273 				at_xdmac_control(chan, DMA_PAUSE, 0);
1274 			atchan->save_cim = at_xdmac_chan_read(atchan, AT_XDMAC_CIM);
1275 			atchan->save_cnda = at_xdmac_chan_read(atchan, AT_XDMAC_CNDA);
1276 			atchan->save_cndc = at_xdmac_chan_read(atchan, AT_XDMAC_CNDC);
1277 		}
1278 	}
1279 	atxdmac->save_gim = at_xdmac_read(atxdmac, AT_XDMAC_GIM);
1280 
1281 	at_xdmac_off(atxdmac);
1282 	clk_disable_unprepare(atxdmac->clk);
1283 	return 0;
1284 }
1285 
1286 static int atmel_xdmac_resume(struct device *dev)
1287 {
1288 	struct platform_device	*pdev = to_platform_device(dev);
1289 	struct at_xdmac		*atxdmac = platform_get_drvdata(pdev);
1290 	struct at_xdmac_chan	*atchan;
1291 	struct dma_chan		*chan, *_chan;
1292 	int			i;
1293 	u32			cfg;
1294 
1295 	clk_prepare_enable(atxdmac->clk);
1296 
1297 	/* Clear pending interrupts. */
1298 	for (i = 0; i < atxdmac->dma.chancnt; i++) {
1299 		atchan = &atxdmac->chan[i];
1300 		while (at_xdmac_chan_read(atchan, AT_XDMAC_CIS))
1301 			cpu_relax();
1302 	}
1303 
1304 	at_xdmac_write(atxdmac, AT_XDMAC_GIE, atxdmac->save_gim);
1305 	at_xdmac_write(atxdmac, AT_XDMAC_GE, atxdmac->save_gs);
1306 	list_for_each_entry_safe(chan, _chan, &atxdmac->dma.channels, device_node) {
1307 		atchan = to_at_xdmac_chan(chan);
1308 		cfg = atchan->cfg[AT_XDMAC_CUR_CFG];
1309 		at_xdmac_chan_write(atchan, AT_XDMAC_CC, cfg);
1310 		if (at_xdmac_chan_is_cyclic(atchan)) {
1311 			at_xdmac_chan_write(atchan, AT_XDMAC_CNDA, atchan->save_cnda);
1312 			at_xdmac_chan_write(atchan, AT_XDMAC_CNDC, atchan->save_cndc);
1313 			at_xdmac_chan_write(atchan, AT_XDMAC_CIE, atchan->save_cim);
1314 			wmb();
1315 			at_xdmac_write(atxdmac, AT_XDMAC_GE, atchan->mask);
1316 		}
1317 	}
1318 	return 0;
1319 }
1320 #endif /* CONFIG_PM_SLEEP */
1321 
1322 static int at_xdmac_probe(struct platform_device *pdev)
1323 {
1324 	struct resource	*res;
1325 	struct at_xdmac	*atxdmac;
1326 	int		irq, size, nr_channels, i, ret;
1327 	void __iomem	*base;
1328 	u32		reg;
1329 
1330 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1331 	if (!res)
1332 		return -EINVAL;
1333 
1334 	irq = platform_get_irq(pdev, 0);
1335 	if (irq < 0)
1336 		return irq;
1337 
1338 	base = devm_ioremap_resource(&pdev->dev, res);
1339 	if (IS_ERR(base))
1340 		return PTR_ERR(base);
1341 
1342 	/*
1343 	 * Read number of xdmac channels, read helper function can't be used
1344 	 * since atxdmac is not yet allocated and we need to know the number
1345 	 * of channels to do the allocation.
1346 	 */
1347 	reg = readl_relaxed(base + AT_XDMAC_GTYPE);
1348 	nr_channels = AT_XDMAC_NB_CH(reg);
1349 	if (nr_channels > AT_XDMAC_MAX_CHAN) {
1350 		dev_err(&pdev->dev, "invalid number of channels (%u)\n",
1351 			nr_channels);
1352 		return -EINVAL;
1353 	}
1354 
1355 	size = sizeof(*atxdmac);
1356 	size += nr_channels * sizeof(struct at_xdmac_chan);
1357 	atxdmac = devm_kzalloc(&pdev->dev, size, GFP_KERNEL);
1358 	if (!atxdmac) {
1359 		dev_err(&pdev->dev, "can't allocate at_xdmac structure\n");
1360 		return -ENOMEM;
1361 	}
1362 
1363 	atxdmac->regs = base;
1364 	atxdmac->irq = irq;
1365 
1366 	atxdmac->clk = devm_clk_get(&pdev->dev, "dma_clk");
1367 	if (IS_ERR(atxdmac->clk)) {
1368 		dev_err(&pdev->dev, "can't get dma_clk\n");
1369 		return PTR_ERR(atxdmac->clk);
1370 	}
1371 
1372 	/* Do not use dev res to prevent races with tasklet */
1373 	ret = request_irq(atxdmac->irq, at_xdmac_interrupt, 0, "at_xdmac", atxdmac);
1374 	if (ret) {
1375 		dev_err(&pdev->dev, "can't request irq\n");
1376 		return ret;
1377 	}
1378 
1379 	ret = clk_prepare_enable(atxdmac->clk);
1380 	if (ret) {
1381 		dev_err(&pdev->dev, "can't prepare or enable clock\n");
1382 		goto err_free_irq;
1383 	}
1384 
1385 	atxdmac->at_xdmac_desc_pool =
1386 		dmam_pool_create(dev_name(&pdev->dev), &pdev->dev,
1387 				sizeof(struct at_xdmac_desc), 4, 0);
1388 	if (!atxdmac->at_xdmac_desc_pool) {
1389 		dev_err(&pdev->dev, "no memory for descriptors dma pool\n");
1390 		ret = -ENOMEM;
1391 		goto err_clk_disable;
1392 	}
1393 
1394 	dma_cap_set(DMA_CYCLIC, atxdmac->dma.cap_mask);
1395 	dma_cap_set(DMA_MEMCPY, atxdmac->dma.cap_mask);
1396 	dma_cap_set(DMA_SLAVE, atxdmac->dma.cap_mask);
1397 	/*
1398 	 * Without DMA_PRIVATE the driver is not able to allocate more than
1399 	 * one channel, second allocation fails in private_candidate.
1400 	 */
1401 	dma_cap_set(DMA_PRIVATE, atxdmac->dma.cap_mask);
1402 	atxdmac->dma.dev				= &pdev->dev;
1403 	atxdmac->dma.device_alloc_chan_resources	= at_xdmac_alloc_chan_resources;
1404 	atxdmac->dma.device_free_chan_resources		= at_xdmac_free_chan_resources;
1405 	atxdmac->dma.device_tx_status			= at_xdmac_tx_status;
1406 	atxdmac->dma.device_issue_pending		= at_xdmac_issue_pending;
1407 	atxdmac->dma.device_prep_dma_cyclic		= at_xdmac_prep_dma_cyclic;
1408 	atxdmac->dma.device_prep_dma_memcpy		= at_xdmac_prep_dma_memcpy;
1409 	atxdmac->dma.device_prep_slave_sg		= at_xdmac_prep_slave_sg;
1410 	atxdmac->dma.device_control			= at_xdmac_control;
1411 	atxdmac->dma.device_slave_caps			= at_xdmac_device_slave_caps;
1412 
1413 	/* Disable all chans and interrupts. */
1414 	at_xdmac_off(atxdmac);
1415 
1416 	/* Init channels. */
1417 	INIT_LIST_HEAD(&atxdmac->dma.channels);
1418 	for (i = 0; i < nr_channels; i++) {
1419 		struct at_xdmac_chan *atchan = &atxdmac->chan[i];
1420 
1421 		atchan->chan.device = &atxdmac->dma;
1422 		list_add_tail(&atchan->chan.device_node,
1423 			      &atxdmac->dma.channels);
1424 
1425 		atchan->ch_regs = at_xdmac_chan_reg_base(atxdmac, i);
1426 		atchan->mask = 1 << i;
1427 
1428 		spin_lock_init(&atchan->lock);
1429 		INIT_LIST_HEAD(&atchan->xfers_list);
1430 		INIT_LIST_HEAD(&atchan->free_descs_list);
1431 		tasklet_init(&atchan->tasklet, at_xdmac_tasklet,
1432 			     (unsigned long)atchan);
1433 
1434 		/* Clear pending interrupts. */
1435 		while (at_xdmac_chan_read(atchan, AT_XDMAC_CIS))
1436 			cpu_relax();
1437 	}
1438 	platform_set_drvdata(pdev, atxdmac);
1439 
1440 	ret = dma_async_device_register(&atxdmac->dma);
1441 	if (ret) {
1442 		dev_err(&pdev->dev, "fail to register DMA engine device\n");
1443 		goto err_clk_disable;
1444 	}
1445 
1446 	ret = of_dma_controller_register(pdev->dev.of_node,
1447 					 at_xdmac_xlate, atxdmac);
1448 	if (ret) {
1449 		dev_err(&pdev->dev, "could not register of dma controller\n");
1450 		goto err_dma_unregister;
1451 	}
1452 
1453 	dev_info(&pdev->dev, "%d channels, mapped at 0x%p\n",
1454 		 nr_channels, atxdmac->regs);
1455 
1456 	return 0;
1457 
1458 err_dma_unregister:
1459 	dma_async_device_unregister(&atxdmac->dma);
1460 err_clk_disable:
1461 	clk_disable_unprepare(atxdmac->clk);
1462 err_free_irq:
1463 	free_irq(atxdmac->irq, atxdmac->dma.dev);
1464 	return ret;
1465 }
1466 
1467 static int at_xdmac_remove(struct platform_device *pdev)
1468 {
1469 	struct at_xdmac	*atxdmac = (struct at_xdmac *)platform_get_drvdata(pdev);
1470 	int		i;
1471 
1472 	at_xdmac_off(atxdmac);
1473 	of_dma_controller_free(pdev->dev.of_node);
1474 	dma_async_device_unregister(&atxdmac->dma);
1475 	clk_disable_unprepare(atxdmac->clk);
1476 
1477 	synchronize_irq(atxdmac->irq);
1478 
1479 	free_irq(atxdmac->irq, atxdmac->dma.dev);
1480 
1481 	for (i = 0; i < atxdmac->dma.chancnt; i++) {
1482 		struct at_xdmac_chan *atchan = &atxdmac->chan[i];
1483 
1484 		tasklet_kill(&atchan->tasklet);
1485 		at_xdmac_free_chan_resources(&atchan->chan);
1486 	}
1487 
1488 	return 0;
1489 }
1490 
1491 static const struct dev_pm_ops atmel_xdmac_dev_pm_ops = {
1492 	.prepare	= atmel_xdmac_prepare,
1493 	SET_LATE_SYSTEM_SLEEP_PM_OPS(atmel_xdmac_suspend, atmel_xdmac_resume)
1494 };
1495 
1496 static const struct of_device_id atmel_xdmac_dt_ids[] = {
1497 	{
1498 		.compatible = "atmel,sama5d4-dma",
1499 	}, {
1500 		/* sentinel */
1501 	}
1502 };
1503 MODULE_DEVICE_TABLE(of, atmel_xdmac_dt_ids);
1504 
1505 static struct platform_driver at_xdmac_driver = {
1506 	.probe		= at_xdmac_probe,
1507 	.remove		= at_xdmac_remove,
1508 	.driver = {
1509 		.name		= "at_xdmac",
1510 		.owner		= THIS_MODULE,
1511 		.of_match_table	= of_match_ptr(atmel_xdmac_dt_ids),
1512 		.pm		= &atmel_xdmac_dev_pm_ops,
1513 	}
1514 };
1515 
1516 static int __init at_xdmac_init(void)
1517 {
1518 	return platform_driver_probe(&at_xdmac_driver, at_xdmac_probe);
1519 }
1520 subsys_initcall(at_xdmac_init);
1521 
1522 MODULE_DESCRIPTION("Atmel Extended DMA Controller driver");
1523 MODULE_AUTHOR("Ludovic Desroches <ludovic.desroches@atmel.com>");
1524 MODULE_LICENSE("GPL");
1525