xref: /kernel/linux/linux-5.10/drivers/dma/at_xdmac.c (revision 8c2ecf20)
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Driver for the Atmel Extensible DMA Controller (aka XDMAC on AT91 systems)
4 *
5 * Copyright (C) 2014 Atmel Corporation
6 *
7 * Author: Ludovic Desroches <ludovic.desroches@atmel.com>
8 */
9
10#include <asm/barrier.h>
11#include <dt-bindings/dma/at91.h>
12#include <linux/clk.h>
13#include <linux/dmaengine.h>
14#include <linux/dmapool.h>
15#include <linux/interrupt.h>
16#include <linux/irq.h>
17#include <linux/kernel.h>
18#include <linux/list.h>
19#include <linux/module.h>
20#include <linux/of_dma.h>
21#include <linux/of_platform.h>
22#include <linux/platform_device.h>
23#include <linux/pm.h>
24
25#include "dmaengine.h"
26
27/* Global registers */
28#define AT_XDMAC_GTYPE		0x00	/* Global Type Register */
29#define		AT_XDMAC_NB_CH(i)	(((i) & 0x1F) + 1)		/* Number of Channels Minus One */
30#define		AT_XDMAC_FIFO_SZ(i)	(((i) >> 5) & 0x7FF)		/* Number of Bytes */
31#define		AT_XDMAC_NB_REQ(i)	((((i) >> 16) & 0x3F) + 1)	/* Number of Peripheral Requests Minus One */
32#define AT_XDMAC_GCFG		0x04	/* Global Configuration Register */
33#define AT_XDMAC_GWAC		0x08	/* Global Weighted Arbiter Configuration Register */
34#define AT_XDMAC_GIE		0x0C	/* Global Interrupt Enable Register */
35#define AT_XDMAC_GID		0x10	/* Global Interrupt Disable Register */
36#define AT_XDMAC_GIM		0x14	/* Global Interrupt Mask Register */
37#define AT_XDMAC_GIS		0x18	/* Global Interrupt Status Register */
38#define AT_XDMAC_GE		0x1C	/* Global Channel Enable Register */
39#define AT_XDMAC_GD		0x20	/* Global Channel Disable Register */
40#define AT_XDMAC_GS		0x24	/* Global Channel Status Register */
41#define AT_XDMAC_GRS		0x28	/* Global Channel Read Suspend Register */
42#define AT_XDMAC_GWS		0x2C	/* Global Write Suspend Register */
43#define AT_XDMAC_GRWS		0x30	/* Global Channel Read Write Suspend Register */
44#define AT_XDMAC_GRWR		0x34	/* Global Channel Read Write Resume Register */
45#define AT_XDMAC_GSWR		0x38	/* Global Channel Software Request Register */
46#define AT_XDMAC_GSWS		0x3C	/* Global channel Software Request Status Register */
47#define AT_XDMAC_GSWF		0x40	/* Global Channel Software Flush Request Register */
48#define AT_XDMAC_VERSION	0xFFC	/* XDMAC Version Register */
49
50/* Channel relative registers offsets */
51#define AT_XDMAC_CIE		0x00	/* Channel Interrupt Enable Register */
52#define		AT_XDMAC_CIE_BIE	BIT(0)	/* End of Block Interrupt Enable Bit */
53#define		AT_XDMAC_CIE_LIE	BIT(1)	/* End of Linked List Interrupt Enable Bit */
54#define		AT_XDMAC_CIE_DIE	BIT(2)	/* End of Disable Interrupt Enable Bit */
55#define		AT_XDMAC_CIE_FIE	BIT(3)	/* End of Flush Interrupt Enable Bit */
56#define		AT_XDMAC_CIE_RBEIE	BIT(4)	/* Read Bus Error Interrupt Enable Bit */
57#define		AT_XDMAC_CIE_WBEIE	BIT(5)	/* Write Bus Error Interrupt Enable Bit */
58#define		AT_XDMAC_CIE_ROIE	BIT(6)	/* Request Overflow Interrupt Enable Bit */
59#define AT_XDMAC_CID		0x04	/* Channel Interrupt Disable Register */
60#define		AT_XDMAC_CID_BID	BIT(0)	/* End of Block Interrupt Disable Bit */
61#define		AT_XDMAC_CID_LID	BIT(1)	/* End of Linked List Interrupt Disable Bit */
62#define		AT_XDMAC_CID_DID	BIT(2)	/* End of Disable Interrupt Disable Bit */
63#define		AT_XDMAC_CID_FID	BIT(3)	/* End of Flush Interrupt Disable Bit */
64#define		AT_XDMAC_CID_RBEID	BIT(4)	/* Read Bus Error Interrupt Disable Bit */
65#define		AT_XDMAC_CID_WBEID	BIT(5)	/* Write Bus Error Interrupt Disable Bit */
66#define		AT_XDMAC_CID_ROID	BIT(6)	/* Request Overflow Interrupt Disable Bit */
67#define AT_XDMAC_CIM		0x08	/* Channel Interrupt Mask Register */
68#define		AT_XDMAC_CIM_BIM	BIT(0)	/* End of Block Interrupt Mask Bit */
69#define		AT_XDMAC_CIM_LIM	BIT(1)	/* End of Linked List Interrupt Mask Bit */
70#define		AT_XDMAC_CIM_DIM	BIT(2)	/* End of Disable Interrupt Mask Bit */
71#define		AT_XDMAC_CIM_FIM	BIT(3)	/* End of Flush Interrupt Mask Bit */
72#define		AT_XDMAC_CIM_RBEIM	BIT(4)	/* Read Bus Error Interrupt Mask Bit */
73#define		AT_XDMAC_CIM_WBEIM	BIT(5)	/* Write Bus Error Interrupt Mask Bit */
74#define		AT_XDMAC_CIM_ROIM	BIT(6)	/* Request Overflow Interrupt Mask Bit */
75#define AT_XDMAC_CIS		0x0C	/* Channel Interrupt Status Register */
76#define		AT_XDMAC_CIS_BIS	BIT(0)	/* End of Block Interrupt Status Bit */
77#define		AT_XDMAC_CIS_LIS	BIT(1)	/* End of Linked List Interrupt Status Bit */
78#define		AT_XDMAC_CIS_DIS	BIT(2)	/* End of Disable Interrupt Status Bit */
79#define		AT_XDMAC_CIS_FIS	BIT(3)	/* End of Flush Interrupt Status Bit */
80#define		AT_XDMAC_CIS_RBEIS	BIT(4)	/* Read Bus Error Interrupt Status Bit */
81#define		AT_XDMAC_CIS_WBEIS	BIT(5)	/* Write Bus Error Interrupt Status Bit */
82#define		AT_XDMAC_CIS_ROIS	BIT(6)	/* Request Overflow Interrupt Status Bit */
83#define AT_XDMAC_CSA		0x10	/* Channel Source Address Register */
84#define AT_XDMAC_CDA		0x14	/* Channel Destination Address Register */
85#define AT_XDMAC_CNDA		0x18	/* Channel Next Descriptor Address Register */
86#define		AT_XDMAC_CNDA_NDAIF(i)	((i) & 0x1)			/* Channel x Next Descriptor Interface */
87#define		AT_XDMAC_CNDA_NDA(i)	((i) & 0xfffffffc)		/* Channel x Next Descriptor Address */
88#define AT_XDMAC_CNDC		0x1C	/* Channel Next Descriptor Control Register */
89#define		AT_XDMAC_CNDC_NDE		(0x1 << 0)		/* Channel x Next Descriptor Enable */
90#define		AT_XDMAC_CNDC_NDSUP		(0x1 << 1)		/* Channel x Next Descriptor Source Update */
91#define		AT_XDMAC_CNDC_NDDUP		(0x1 << 2)		/* Channel x Next Descriptor Destination Update */
92#define		AT_XDMAC_CNDC_NDVIEW_MASK	GENMASK(28, 27)
93#define		AT_XDMAC_CNDC_NDVIEW_NDV0	(0x0 << 3)		/* Channel x Next Descriptor View 0 */
94#define		AT_XDMAC_CNDC_NDVIEW_NDV1	(0x1 << 3)		/* Channel x Next Descriptor View 1 */
95#define		AT_XDMAC_CNDC_NDVIEW_NDV2	(0x2 << 3)		/* Channel x Next Descriptor View 2 */
96#define		AT_XDMAC_CNDC_NDVIEW_NDV3	(0x3 << 3)		/* Channel x Next Descriptor View 3 */
97#define AT_XDMAC_CUBC		0x20	/* Channel Microblock Control Register */
98#define AT_XDMAC_CBC		0x24	/* Channel Block Control Register */
99#define AT_XDMAC_CC		0x28	/* Channel Configuration Register */
100#define		AT_XDMAC_CC_TYPE	(0x1 << 0)	/* Channel Transfer Type */
101#define			AT_XDMAC_CC_TYPE_MEM_TRAN	(0x0 << 0)	/* Memory to Memory Transfer */
102#define			AT_XDMAC_CC_TYPE_PER_TRAN	(0x1 << 0)	/* Peripheral to Memory or Memory to Peripheral Transfer */
103#define		AT_XDMAC_CC_MBSIZE_MASK	(0x3 << 1)
104#define			AT_XDMAC_CC_MBSIZE_SINGLE	(0x0 << 1)
105#define			AT_XDMAC_CC_MBSIZE_FOUR		(0x1 << 1)
106#define			AT_XDMAC_CC_MBSIZE_EIGHT	(0x2 << 1)
107#define			AT_XDMAC_CC_MBSIZE_SIXTEEN	(0x3 << 1)
108#define		AT_XDMAC_CC_DSYNC	(0x1 << 4)	/* Channel Synchronization */
109#define			AT_XDMAC_CC_DSYNC_PER2MEM	(0x0 << 4)
110#define			AT_XDMAC_CC_DSYNC_MEM2PER	(0x1 << 4)
111#define		AT_XDMAC_CC_PROT	(0x1 << 5)	/* Channel Protection */
112#define			AT_XDMAC_CC_PROT_SEC		(0x0 << 5)
113#define			AT_XDMAC_CC_PROT_UNSEC		(0x1 << 5)
114#define		AT_XDMAC_CC_SWREQ	(0x1 << 6)	/* Channel Software Request Trigger */
115#define			AT_XDMAC_CC_SWREQ_HWR_CONNECTED	(0x0 << 6)
116#define			AT_XDMAC_CC_SWREQ_SWR_CONNECTED	(0x1 << 6)
117#define		AT_XDMAC_CC_MEMSET	(0x1 << 7)	/* Channel Fill Block of memory */
118#define			AT_XDMAC_CC_MEMSET_NORMAL_MODE	(0x0 << 7)
119#define			AT_XDMAC_CC_MEMSET_HW_MODE	(0x1 << 7)
120#define		AT_XDMAC_CC_CSIZE(i)	((0x7 & (i)) << 8)	/* Channel Chunk Size */
121#define		AT_XDMAC_CC_DWIDTH_OFFSET	11
122#define		AT_XDMAC_CC_DWIDTH_MASK	(0x3 << AT_XDMAC_CC_DWIDTH_OFFSET)
123#define		AT_XDMAC_CC_DWIDTH(i)	((0x3 & (i)) << AT_XDMAC_CC_DWIDTH_OFFSET)	/* Channel Data Width */
124#define			AT_XDMAC_CC_DWIDTH_BYTE		0x0
125#define			AT_XDMAC_CC_DWIDTH_HALFWORD	0x1
126#define			AT_XDMAC_CC_DWIDTH_WORD		0x2
127#define			AT_XDMAC_CC_DWIDTH_DWORD	0x3
128#define		AT_XDMAC_CC_SIF(i)	((0x1 & (i)) << 13)	/* Channel Source Interface Identifier */
129#define		AT_XDMAC_CC_DIF(i)	((0x1 & (i)) << 14)	/* Channel Destination Interface Identifier */
130#define		AT_XDMAC_CC_SAM_MASK	(0x3 << 16)	/* Channel Source Addressing Mode */
131#define			AT_XDMAC_CC_SAM_FIXED_AM	(0x0 << 16)
132#define			AT_XDMAC_CC_SAM_INCREMENTED_AM	(0x1 << 16)
133#define			AT_XDMAC_CC_SAM_UBS_AM		(0x2 << 16)
134#define			AT_XDMAC_CC_SAM_UBS_DS_AM	(0x3 << 16)
135#define		AT_XDMAC_CC_DAM_MASK	(0x3 << 18)	/* Channel Source Addressing Mode */
136#define			AT_XDMAC_CC_DAM_FIXED_AM	(0x0 << 18)
137#define			AT_XDMAC_CC_DAM_INCREMENTED_AM	(0x1 << 18)
138#define			AT_XDMAC_CC_DAM_UBS_AM		(0x2 << 18)
139#define			AT_XDMAC_CC_DAM_UBS_DS_AM	(0x3 << 18)
140#define		AT_XDMAC_CC_INITD	(0x1 << 21)	/* Channel Initialization Terminated (read only) */
141#define			AT_XDMAC_CC_INITD_TERMINATED	(0x0 << 21)
142#define			AT_XDMAC_CC_INITD_IN_PROGRESS	(0x1 << 21)
143#define		AT_XDMAC_CC_RDIP	(0x1 << 22)	/* Read in Progress (read only) */
144#define			AT_XDMAC_CC_RDIP_DONE		(0x0 << 22)
145#define			AT_XDMAC_CC_RDIP_IN_PROGRESS	(0x1 << 22)
146#define		AT_XDMAC_CC_WRIP	(0x1 << 23)	/* Write in Progress (read only) */
147#define			AT_XDMAC_CC_WRIP_DONE		(0x0 << 23)
148#define			AT_XDMAC_CC_WRIP_IN_PROGRESS	(0x1 << 23)
149#define		AT_XDMAC_CC_PERID(i)	((0x7f & (i)) << 24)	/* Channel Peripheral Identifier */
150#define AT_XDMAC_CDS_MSP	0x2C	/* Channel Data Stride Memory Set Pattern */
151#define AT_XDMAC_CSUS		0x30	/* Channel Source Microblock Stride */
152#define AT_XDMAC_CDUS		0x34	/* Channel Destination Microblock Stride */
153
154#define AT_XDMAC_CHAN_REG_BASE	0x50	/* Channel registers base address */
155
156/* Microblock control members */
157#define AT_XDMAC_MBR_UBC_UBLEN_MAX	0xFFFFFFUL	/* Maximum Microblock Length */
158#define AT_XDMAC_MBR_UBC_NDE		(0x1 << 24)	/* Next Descriptor Enable */
159#define AT_XDMAC_MBR_UBC_NSEN		(0x1 << 25)	/* Next Descriptor Source Update */
160#define AT_XDMAC_MBR_UBC_NDEN		(0x1 << 26)	/* Next Descriptor Destination Update */
161#define AT_XDMAC_MBR_UBC_NDV0		(0x0 << 27)	/* Next Descriptor View 0 */
162#define AT_XDMAC_MBR_UBC_NDV1		(0x1 << 27)	/* Next Descriptor View 1 */
163#define AT_XDMAC_MBR_UBC_NDV2		(0x2 << 27)	/* Next Descriptor View 2 */
164#define AT_XDMAC_MBR_UBC_NDV3		(0x3 << 27)	/* Next Descriptor View 3 */
165
166#define AT_XDMAC_MAX_CHAN	0x20
167#define AT_XDMAC_MAX_CSIZE	16	/* 16 data */
168#define AT_XDMAC_MAX_DWIDTH	8	/* 64 bits */
169#define AT_XDMAC_RESIDUE_MAX_RETRIES	5
170
171#define AT_XDMAC_DMA_BUSWIDTHS\
172	(BIT(DMA_SLAVE_BUSWIDTH_UNDEFINED) |\
173	BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |\
174	BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |\
175	BIT(DMA_SLAVE_BUSWIDTH_4_BYTES) |\
176	BIT(DMA_SLAVE_BUSWIDTH_8_BYTES))
177
178enum atc_status {
179	AT_XDMAC_CHAN_IS_CYCLIC = 0,
180	AT_XDMAC_CHAN_IS_PAUSED,
181};
182
183/* ----- Channels ----- */
184struct at_xdmac_chan {
185	struct dma_chan			chan;
186	void __iomem			*ch_regs;
187	u32				mask;		/* Channel Mask */
188	u32				cfg;		/* Channel Configuration Register */
189	u8				perid;		/* Peripheral ID */
190	u8				perif;		/* Peripheral Interface */
191	u8				memif;		/* Memory Interface */
192	u32				save_cc;
193	u32				save_cim;
194	u32				save_cnda;
195	u32				save_cndc;
196	u32				irq_status;
197	unsigned long			status;
198	struct tasklet_struct		tasklet;
199	struct dma_slave_config		sconfig;
200
201	spinlock_t			lock;
202
203	struct list_head		xfers_list;
204	struct list_head		free_descs_list;
205};
206
207
208/* ----- Controller ----- */
209struct at_xdmac {
210	struct dma_device	dma;
211	void __iomem		*regs;
212	int			irq;
213	struct clk		*clk;
214	u32			save_gim;
215	u32			save_gs;
216	struct dma_pool		*at_xdmac_desc_pool;
217	struct at_xdmac_chan	chan[];
218};
219
220
221/* ----- Descriptors ----- */
222
223/* Linked List Descriptor */
224struct at_xdmac_lld {
225	u32 mbr_nda;	/* Next Descriptor Member */
226	u32 mbr_ubc;	/* Microblock Control Member */
227	u32 mbr_sa;	/* Source Address Member */
228	u32 mbr_da;	/* Destination Address Member */
229	u32 mbr_cfg;	/* Configuration Register */
230	u32 mbr_bc;	/* Block Control Register */
231	u32 mbr_ds;	/* Data Stride Register */
232	u32 mbr_sus;	/* Source Microblock Stride Register */
233	u32 mbr_dus;	/* Destination Microblock Stride Register */
234};
235
236/* 64-bit alignment needed to update CNDA and CUBC registers in an atomic way. */
237struct at_xdmac_desc {
238	struct at_xdmac_lld		lld;
239	enum dma_transfer_direction	direction;
240	struct dma_async_tx_descriptor	tx_dma_desc;
241	struct list_head		desc_node;
242	/* Following members are only used by the first descriptor */
243	bool				active_xfer;
244	unsigned int			xfer_size;
245	struct list_head		descs_list;
246	struct list_head		xfer_node;
247} __aligned(sizeof(u64));
248
249static inline void __iomem *at_xdmac_chan_reg_base(struct at_xdmac *atxdmac, unsigned int chan_nb)
250{
251	return atxdmac->regs + (AT_XDMAC_CHAN_REG_BASE + chan_nb * 0x40);
252}
253
254#define at_xdmac_read(atxdmac, reg) readl_relaxed((atxdmac)->regs + (reg))
255#define at_xdmac_write(atxdmac, reg, value) \
256	writel_relaxed((value), (atxdmac)->regs + (reg))
257
258#define at_xdmac_chan_read(atchan, reg) readl_relaxed((atchan)->ch_regs + (reg))
259#define at_xdmac_chan_write(atchan, reg, value) writel_relaxed((value), (atchan)->ch_regs + (reg))
260
261static inline struct at_xdmac_chan *to_at_xdmac_chan(struct dma_chan *dchan)
262{
263	return container_of(dchan, struct at_xdmac_chan, chan);
264}
265
266static struct device *chan2dev(struct dma_chan *chan)
267{
268	return &chan->dev->device;
269}
270
271static inline struct at_xdmac *to_at_xdmac(struct dma_device *ddev)
272{
273	return container_of(ddev, struct at_xdmac, dma);
274}
275
276static inline struct at_xdmac_desc *txd_to_at_desc(struct dma_async_tx_descriptor *txd)
277{
278	return container_of(txd, struct at_xdmac_desc, tx_dma_desc);
279}
280
281static inline int at_xdmac_chan_is_cyclic(struct at_xdmac_chan *atchan)
282{
283	return test_bit(AT_XDMAC_CHAN_IS_CYCLIC, &atchan->status);
284}
285
286static inline int at_xdmac_chan_is_paused(struct at_xdmac_chan *atchan)
287{
288	return test_bit(AT_XDMAC_CHAN_IS_PAUSED, &atchan->status);
289}
290
291static inline int at_xdmac_csize(u32 maxburst)
292{
293	int csize;
294
295	csize = ffs(maxburst) - 1;
296	if (csize > 4)
297		csize = -EINVAL;
298
299	return csize;
300};
301
302static inline bool at_xdmac_chan_is_peripheral_xfer(u32 cfg)
303{
304	return cfg & AT_XDMAC_CC_TYPE_PER_TRAN;
305}
306
307static inline u8 at_xdmac_get_dwidth(u32 cfg)
308{
309	return (cfg & AT_XDMAC_CC_DWIDTH_MASK) >> AT_XDMAC_CC_DWIDTH_OFFSET;
310};
311
312static unsigned int init_nr_desc_per_channel = 64;
313module_param(init_nr_desc_per_channel, uint, 0644);
314MODULE_PARM_DESC(init_nr_desc_per_channel,
315		 "initial descriptors per channel (default: 64)");
316
317
318static bool at_xdmac_chan_is_enabled(struct at_xdmac_chan *atchan)
319{
320	return at_xdmac_chan_read(atchan, AT_XDMAC_GS) & atchan->mask;
321}
322
323static void at_xdmac_off(struct at_xdmac *atxdmac)
324{
325	at_xdmac_write(atxdmac, AT_XDMAC_GD, -1L);
326
327	/* Wait that all chans are disabled. */
328	while (at_xdmac_read(atxdmac, AT_XDMAC_GS))
329		cpu_relax();
330
331	at_xdmac_write(atxdmac, AT_XDMAC_GID, -1L);
332}
333
334/* Call with lock hold. */
335static void at_xdmac_start_xfer(struct at_xdmac_chan *atchan,
336				struct at_xdmac_desc *first)
337{
338	struct at_xdmac	*atxdmac = to_at_xdmac(atchan->chan.device);
339	u32		reg;
340
341	dev_vdbg(chan2dev(&atchan->chan), "%s: desc 0x%p\n", __func__, first);
342
343	/* Set transfer as active to not try to start it again. */
344	first->active_xfer = true;
345
346	/* Tell xdmac where to get the first descriptor. */
347	reg = AT_XDMAC_CNDA_NDA(first->tx_dma_desc.phys)
348	      | AT_XDMAC_CNDA_NDAIF(atchan->memif);
349	at_xdmac_chan_write(atchan, AT_XDMAC_CNDA, reg);
350
351	/*
352	 * When doing non cyclic transfer we need to use the next
353	 * descriptor view 2 since some fields of the configuration register
354	 * depend on transfer size and src/dest addresses.
355	 */
356	if (at_xdmac_chan_is_cyclic(atchan))
357		reg = AT_XDMAC_CNDC_NDVIEW_NDV1;
358	else if ((first->lld.mbr_ubc &
359		  AT_XDMAC_CNDC_NDVIEW_MASK) == AT_XDMAC_MBR_UBC_NDV3)
360		reg = AT_XDMAC_CNDC_NDVIEW_NDV3;
361	else
362		reg = AT_XDMAC_CNDC_NDVIEW_NDV2;
363	/*
364	 * Even if the register will be updated from the configuration in the
365	 * descriptor when using view 2 or higher, the PROT bit won't be set
366	 * properly. This bit can be modified only by using the channel
367	 * configuration register.
368	 */
369	at_xdmac_chan_write(atchan, AT_XDMAC_CC, first->lld.mbr_cfg);
370
371	reg |= AT_XDMAC_CNDC_NDDUP
372	       | AT_XDMAC_CNDC_NDSUP
373	       | AT_XDMAC_CNDC_NDE;
374	at_xdmac_chan_write(atchan, AT_XDMAC_CNDC, reg);
375
376	dev_vdbg(chan2dev(&atchan->chan),
377		 "%s: CC=0x%08x CNDA=0x%08x, CNDC=0x%08x, CSA=0x%08x, CDA=0x%08x, CUBC=0x%08x\n",
378		 __func__, at_xdmac_chan_read(atchan, AT_XDMAC_CC),
379		 at_xdmac_chan_read(atchan, AT_XDMAC_CNDA),
380		 at_xdmac_chan_read(atchan, AT_XDMAC_CNDC),
381		 at_xdmac_chan_read(atchan, AT_XDMAC_CSA),
382		 at_xdmac_chan_read(atchan, AT_XDMAC_CDA),
383		 at_xdmac_chan_read(atchan, AT_XDMAC_CUBC));
384
385	at_xdmac_chan_write(atchan, AT_XDMAC_CID, 0xffffffff);
386	reg = AT_XDMAC_CIE_RBEIE | AT_XDMAC_CIE_WBEIE;
387	/*
388	 * Request Overflow Error is only for peripheral synchronized transfers
389	 */
390	if (at_xdmac_chan_is_peripheral_xfer(first->lld.mbr_cfg))
391		reg |= AT_XDMAC_CIE_ROIE;
392
393	/*
394	 * There is no end of list when doing cyclic dma, we need to get
395	 * an interrupt after each periods.
396	 */
397	if (at_xdmac_chan_is_cyclic(atchan))
398		at_xdmac_chan_write(atchan, AT_XDMAC_CIE,
399				    reg | AT_XDMAC_CIE_BIE);
400	else
401		at_xdmac_chan_write(atchan, AT_XDMAC_CIE,
402				    reg | AT_XDMAC_CIE_LIE);
403	at_xdmac_write(atxdmac, AT_XDMAC_GIE, atchan->mask);
404	dev_vdbg(chan2dev(&atchan->chan),
405		 "%s: enable channel (0x%08x)\n", __func__, atchan->mask);
406	wmb();
407	at_xdmac_write(atxdmac, AT_XDMAC_GE, atchan->mask);
408
409	dev_vdbg(chan2dev(&atchan->chan),
410		 "%s: CC=0x%08x CNDA=0x%08x, CNDC=0x%08x, CSA=0x%08x, CDA=0x%08x, CUBC=0x%08x\n",
411		 __func__, at_xdmac_chan_read(atchan, AT_XDMAC_CC),
412		 at_xdmac_chan_read(atchan, AT_XDMAC_CNDA),
413		 at_xdmac_chan_read(atchan, AT_XDMAC_CNDC),
414		 at_xdmac_chan_read(atchan, AT_XDMAC_CSA),
415		 at_xdmac_chan_read(atchan, AT_XDMAC_CDA),
416		 at_xdmac_chan_read(atchan, AT_XDMAC_CUBC));
417
418}
419
420static dma_cookie_t at_xdmac_tx_submit(struct dma_async_tx_descriptor *tx)
421{
422	struct at_xdmac_desc	*desc = txd_to_at_desc(tx);
423	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(tx->chan);
424	dma_cookie_t		cookie;
425	unsigned long		irqflags;
426
427	spin_lock_irqsave(&atchan->lock, irqflags);
428	cookie = dma_cookie_assign(tx);
429
430	list_add_tail(&desc->xfer_node, &atchan->xfers_list);
431	spin_unlock_irqrestore(&atchan->lock, irqflags);
432
433	dev_vdbg(chan2dev(tx->chan), "%s: atchan 0x%p, add desc 0x%p to xfers_list\n",
434		 __func__, atchan, desc);
435
436	return cookie;
437}
438
439static struct at_xdmac_desc *at_xdmac_alloc_desc(struct dma_chan *chan,
440						 gfp_t gfp_flags)
441{
442	struct at_xdmac_desc	*desc;
443	struct at_xdmac		*atxdmac = to_at_xdmac(chan->device);
444	dma_addr_t		phys;
445
446	desc = dma_pool_zalloc(atxdmac->at_xdmac_desc_pool, gfp_flags, &phys);
447	if (desc) {
448		INIT_LIST_HEAD(&desc->descs_list);
449		dma_async_tx_descriptor_init(&desc->tx_dma_desc, chan);
450		desc->tx_dma_desc.tx_submit = at_xdmac_tx_submit;
451		desc->tx_dma_desc.phys = phys;
452	}
453
454	return desc;
455}
456
457static void at_xdmac_init_used_desc(struct at_xdmac_desc *desc)
458{
459	memset(&desc->lld, 0, sizeof(desc->lld));
460	INIT_LIST_HEAD(&desc->descs_list);
461	desc->direction = DMA_TRANS_NONE;
462	desc->xfer_size = 0;
463	desc->active_xfer = false;
464}
465
466/* Call must be protected by lock. */
467static struct at_xdmac_desc *at_xdmac_get_desc(struct at_xdmac_chan *atchan)
468{
469	struct at_xdmac_desc *desc;
470
471	if (list_empty(&atchan->free_descs_list)) {
472		desc = at_xdmac_alloc_desc(&atchan->chan, GFP_NOWAIT);
473	} else {
474		desc = list_first_entry(&atchan->free_descs_list,
475					struct at_xdmac_desc, desc_node);
476		list_del(&desc->desc_node);
477		at_xdmac_init_used_desc(desc);
478	}
479
480	return desc;
481}
482
483static void at_xdmac_queue_desc(struct dma_chan *chan,
484				struct at_xdmac_desc *prev,
485				struct at_xdmac_desc *desc)
486{
487	if (!prev || !desc)
488		return;
489
490	prev->lld.mbr_nda = desc->tx_dma_desc.phys;
491	prev->lld.mbr_ubc |= AT_XDMAC_MBR_UBC_NDE;
492
493	dev_dbg(chan2dev(chan),	"%s: chain lld: prev=0x%p, mbr_nda=%pad\n",
494		__func__, prev, &prev->lld.mbr_nda);
495}
496
497static inline void at_xdmac_increment_block_count(struct dma_chan *chan,
498						  struct at_xdmac_desc *desc)
499{
500	if (!desc)
501		return;
502
503	desc->lld.mbr_bc++;
504
505	dev_dbg(chan2dev(chan),
506		"%s: incrementing the block count of the desc 0x%p\n",
507		__func__, desc);
508}
509
510static struct dma_chan *at_xdmac_xlate(struct of_phandle_args *dma_spec,
511				       struct of_dma *of_dma)
512{
513	struct at_xdmac		*atxdmac = of_dma->of_dma_data;
514	struct at_xdmac_chan	*atchan;
515	struct dma_chan		*chan;
516	struct device		*dev = atxdmac->dma.dev;
517
518	if (dma_spec->args_count != 1) {
519		dev_err(dev, "dma phandler args: bad number of args\n");
520		return NULL;
521	}
522
523	chan = dma_get_any_slave_channel(&atxdmac->dma);
524	if (!chan) {
525		dev_err(dev, "can't get a dma channel\n");
526		return NULL;
527	}
528
529	atchan = to_at_xdmac_chan(chan);
530	atchan->memif = AT91_XDMAC_DT_GET_MEM_IF(dma_spec->args[0]);
531	atchan->perif = AT91_XDMAC_DT_GET_PER_IF(dma_spec->args[0]);
532	atchan->perid = AT91_XDMAC_DT_GET_PERID(dma_spec->args[0]);
533	dev_dbg(dev, "chan dt cfg: memif=%u perif=%u perid=%u\n",
534		 atchan->memif, atchan->perif, atchan->perid);
535
536	return chan;
537}
538
539static int at_xdmac_compute_chan_conf(struct dma_chan *chan,
540				      enum dma_transfer_direction direction)
541{
542	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
543	int			csize, dwidth;
544
545	if (direction == DMA_DEV_TO_MEM) {
546		atchan->cfg =
547			AT91_XDMAC_DT_PERID(atchan->perid)
548			| AT_XDMAC_CC_DAM_INCREMENTED_AM
549			| AT_XDMAC_CC_SAM_FIXED_AM
550			| AT_XDMAC_CC_DIF(atchan->memif)
551			| AT_XDMAC_CC_SIF(atchan->perif)
552			| AT_XDMAC_CC_SWREQ_HWR_CONNECTED
553			| AT_XDMAC_CC_DSYNC_PER2MEM
554			| AT_XDMAC_CC_MBSIZE_SIXTEEN
555			| AT_XDMAC_CC_TYPE_PER_TRAN;
556		csize = ffs(atchan->sconfig.src_maxburst) - 1;
557		if (csize < 0) {
558			dev_err(chan2dev(chan), "invalid src maxburst value\n");
559			return -EINVAL;
560		}
561		atchan->cfg |= AT_XDMAC_CC_CSIZE(csize);
562		dwidth = ffs(atchan->sconfig.src_addr_width) - 1;
563		if (dwidth < 0) {
564			dev_err(chan2dev(chan), "invalid src addr width value\n");
565			return -EINVAL;
566		}
567		atchan->cfg |= AT_XDMAC_CC_DWIDTH(dwidth);
568	} else if (direction == DMA_MEM_TO_DEV) {
569		atchan->cfg =
570			AT91_XDMAC_DT_PERID(atchan->perid)
571			| AT_XDMAC_CC_DAM_FIXED_AM
572			| AT_XDMAC_CC_SAM_INCREMENTED_AM
573			| AT_XDMAC_CC_DIF(atchan->perif)
574			| AT_XDMAC_CC_SIF(atchan->memif)
575			| AT_XDMAC_CC_SWREQ_HWR_CONNECTED
576			| AT_XDMAC_CC_DSYNC_MEM2PER
577			| AT_XDMAC_CC_MBSIZE_SIXTEEN
578			| AT_XDMAC_CC_TYPE_PER_TRAN;
579		csize = ffs(atchan->sconfig.dst_maxburst) - 1;
580		if (csize < 0) {
581			dev_err(chan2dev(chan), "invalid src maxburst value\n");
582			return -EINVAL;
583		}
584		atchan->cfg |= AT_XDMAC_CC_CSIZE(csize);
585		dwidth = ffs(atchan->sconfig.dst_addr_width) - 1;
586		if (dwidth < 0) {
587			dev_err(chan2dev(chan), "invalid dst addr width value\n");
588			return -EINVAL;
589		}
590		atchan->cfg |= AT_XDMAC_CC_DWIDTH(dwidth);
591	}
592
593	dev_dbg(chan2dev(chan),	"%s: cfg=0x%08x\n", __func__, atchan->cfg);
594
595	return 0;
596}
597
598/*
599 * Only check that maxburst and addr width values are supported by the
600 * the controller but not that the configuration is good to perform the
601 * transfer since we don't know the direction at this stage.
602 */
603static int at_xdmac_check_slave_config(struct dma_slave_config *sconfig)
604{
605	if ((sconfig->src_maxburst > AT_XDMAC_MAX_CSIZE)
606	    || (sconfig->dst_maxburst > AT_XDMAC_MAX_CSIZE))
607		return -EINVAL;
608
609	if ((sconfig->src_addr_width > AT_XDMAC_MAX_DWIDTH)
610	    || (sconfig->dst_addr_width > AT_XDMAC_MAX_DWIDTH))
611		return -EINVAL;
612
613	return 0;
614}
615
616static int at_xdmac_set_slave_config(struct dma_chan *chan,
617				      struct dma_slave_config *sconfig)
618{
619	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
620
621	if (at_xdmac_check_slave_config(sconfig)) {
622		dev_err(chan2dev(chan), "invalid slave configuration\n");
623		return -EINVAL;
624	}
625
626	memcpy(&atchan->sconfig, sconfig, sizeof(atchan->sconfig));
627
628	return 0;
629}
630
631static struct dma_async_tx_descriptor *
632at_xdmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
633		       unsigned int sg_len, enum dma_transfer_direction direction,
634		       unsigned long flags, void *context)
635{
636	struct at_xdmac_chan		*atchan = to_at_xdmac_chan(chan);
637	struct at_xdmac_desc		*first = NULL, *prev = NULL;
638	struct scatterlist		*sg;
639	int				i;
640	unsigned int			xfer_size = 0;
641	unsigned long			irqflags;
642	struct dma_async_tx_descriptor	*ret = NULL;
643
644	if (!sgl)
645		return NULL;
646
647	if (!is_slave_direction(direction)) {
648		dev_err(chan2dev(chan), "invalid DMA direction\n");
649		return NULL;
650	}
651
652	dev_dbg(chan2dev(chan), "%s: sg_len=%d, dir=%s, flags=0x%lx\n",
653		 __func__, sg_len,
654		 direction == DMA_MEM_TO_DEV ? "to device" : "from device",
655		 flags);
656
657	/* Protect dma_sconfig field that can be modified by set_slave_conf. */
658	spin_lock_irqsave(&atchan->lock, irqflags);
659
660	if (at_xdmac_compute_chan_conf(chan, direction))
661		goto spin_unlock;
662
663	/* Prepare descriptors. */
664	for_each_sg(sgl, sg, sg_len, i) {
665		struct at_xdmac_desc	*desc = NULL;
666		u32			len, mem, dwidth, fixed_dwidth;
667
668		len = sg_dma_len(sg);
669		mem = sg_dma_address(sg);
670		if (unlikely(!len)) {
671			dev_err(chan2dev(chan), "sg data length is zero\n");
672			goto spin_unlock;
673		}
674		dev_dbg(chan2dev(chan), "%s: * sg%d len=%u, mem=0x%08x\n",
675			 __func__, i, len, mem);
676
677		desc = at_xdmac_get_desc(atchan);
678		if (!desc) {
679			dev_err(chan2dev(chan), "can't get descriptor\n");
680			if (first)
681				list_splice_tail_init(&first->descs_list,
682						      &atchan->free_descs_list);
683			goto spin_unlock;
684		}
685
686		/* Linked list descriptor setup. */
687		if (direction == DMA_DEV_TO_MEM) {
688			desc->lld.mbr_sa = atchan->sconfig.src_addr;
689			desc->lld.mbr_da = mem;
690		} else {
691			desc->lld.mbr_sa = mem;
692			desc->lld.mbr_da = atchan->sconfig.dst_addr;
693		}
694		dwidth = at_xdmac_get_dwidth(atchan->cfg);
695		fixed_dwidth = IS_ALIGNED(len, 1 << dwidth)
696			       ? dwidth
697			       : AT_XDMAC_CC_DWIDTH_BYTE;
698		desc->lld.mbr_ubc = AT_XDMAC_MBR_UBC_NDV2			/* next descriptor view */
699			| AT_XDMAC_MBR_UBC_NDEN					/* next descriptor dst parameter update */
700			| AT_XDMAC_MBR_UBC_NSEN					/* next descriptor src parameter update */
701			| (len >> fixed_dwidth);				/* microblock length */
702		desc->lld.mbr_cfg = (atchan->cfg & ~AT_XDMAC_CC_DWIDTH_MASK) |
703				    AT_XDMAC_CC_DWIDTH(fixed_dwidth);
704		dev_dbg(chan2dev(chan),
705			 "%s: lld: mbr_sa=%pad, mbr_da=%pad, mbr_ubc=0x%08x\n",
706			 __func__, &desc->lld.mbr_sa, &desc->lld.mbr_da, desc->lld.mbr_ubc);
707
708		/* Chain lld. */
709		if (prev)
710			at_xdmac_queue_desc(chan, prev, desc);
711
712		prev = desc;
713		if (!first)
714			first = desc;
715
716		dev_dbg(chan2dev(chan), "%s: add desc 0x%p to descs_list 0x%p\n",
717			 __func__, desc, first);
718		list_add_tail(&desc->desc_node, &first->descs_list);
719		xfer_size += len;
720	}
721
722
723	first->tx_dma_desc.flags = flags;
724	first->xfer_size = xfer_size;
725	first->direction = direction;
726	ret = &first->tx_dma_desc;
727
728spin_unlock:
729	spin_unlock_irqrestore(&atchan->lock, irqflags);
730	return ret;
731}
732
733static struct dma_async_tx_descriptor *
734at_xdmac_prep_dma_cyclic(struct dma_chan *chan, dma_addr_t buf_addr,
735			 size_t buf_len, size_t period_len,
736			 enum dma_transfer_direction direction,
737			 unsigned long flags)
738{
739	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
740	struct at_xdmac_desc	*first = NULL, *prev = NULL;
741	unsigned int		periods = buf_len / period_len;
742	int			i;
743	unsigned long		irqflags;
744
745	dev_dbg(chan2dev(chan), "%s: buf_addr=%pad, buf_len=%zd, period_len=%zd, dir=%s, flags=0x%lx\n",
746		__func__, &buf_addr, buf_len, period_len,
747		direction == DMA_MEM_TO_DEV ? "mem2per" : "per2mem", flags);
748
749	if (!is_slave_direction(direction)) {
750		dev_err(chan2dev(chan), "invalid DMA direction\n");
751		return NULL;
752	}
753
754	if (test_and_set_bit(AT_XDMAC_CHAN_IS_CYCLIC, &atchan->status)) {
755		dev_err(chan2dev(chan), "channel currently used\n");
756		return NULL;
757	}
758
759	if (at_xdmac_compute_chan_conf(chan, direction))
760		return NULL;
761
762	for (i = 0; i < periods; i++) {
763		struct at_xdmac_desc	*desc = NULL;
764
765		spin_lock_irqsave(&atchan->lock, irqflags);
766		desc = at_xdmac_get_desc(atchan);
767		if (!desc) {
768			dev_err(chan2dev(chan), "can't get descriptor\n");
769			if (first)
770				list_splice_tail_init(&first->descs_list,
771						      &atchan->free_descs_list);
772			spin_unlock_irqrestore(&atchan->lock, irqflags);
773			return NULL;
774		}
775		spin_unlock_irqrestore(&atchan->lock, irqflags);
776		dev_dbg(chan2dev(chan),
777			"%s: desc=0x%p, tx_dma_desc.phys=%pad\n",
778			__func__, desc, &desc->tx_dma_desc.phys);
779
780		if (direction == DMA_DEV_TO_MEM) {
781			desc->lld.mbr_sa = atchan->sconfig.src_addr;
782			desc->lld.mbr_da = buf_addr + i * period_len;
783		} else {
784			desc->lld.mbr_sa = buf_addr + i * period_len;
785			desc->lld.mbr_da = atchan->sconfig.dst_addr;
786		}
787		desc->lld.mbr_cfg = atchan->cfg;
788		desc->lld.mbr_ubc = AT_XDMAC_MBR_UBC_NDV1
789			| AT_XDMAC_MBR_UBC_NDEN
790			| AT_XDMAC_MBR_UBC_NSEN
791			| period_len >> at_xdmac_get_dwidth(desc->lld.mbr_cfg);
792
793		dev_dbg(chan2dev(chan),
794			 "%s: lld: mbr_sa=%pad, mbr_da=%pad, mbr_ubc=0x%08x\n",
795			 __func__, &desc->lld.mbr_sa, &desc->lld.mbr_da, desc->lld.mbr_ubc);
796
797		/* Chain lld. */
798		if (prev)
799			at_xdmac_queue_desc(chan, prev, desc);
800
801		prev = desc;
802		if (!first)
803			first = desc;
804
805		dev_dbg(chan2dev(chan), "%s: add desc 0x%p to descs_list 0x%p\n",
806			 __func__, desc, first);
807		list_add_tail(&desc->desc_node, &first->descs_list);
808	}
809
810	at_xdmac_queue_desc(chan, prev, first);
811	first->tx_dma_desc.flags = flags;
812	first->xfer_size = buf_len;
813	first->direction = direction;
814
815	return &first->tx_dma_desc;
816}
817
818static inline u32 at_xdmac_align_width(struct dma_chan *chan, dma_addr_t addr)
819{
820	u32 width;
821
822	/*
823	 * Check address alignment to select the greater data width we
824	 * can use.
825	 *
826	 * Some XDMAC implementations don't provide dword transfer, in
827	 * this case selecting dword has the same behavior as
828	 * selecting word transfers.
829	 */
830	if (!(addr & 7)) {
831		width = AT_XDMAC_CC_DWIDTH_DWORD;
832		dev_dbg(chan2dev(chan), "%s: dwidth: double word\n", __func__);
833	} else if (!(addr & 3)) {
834		width = AT_XDMAC_CC_DWIDTH_WORD;
835		dev_dbg(chan2dev(chan), "%s: dwidth: word\n", __func__);
836	} else if (!(addr & 1)) {
837		width = AT_XDMAC_CC_DWIDTH_HALFWORD;
838		dev_dbg(chan2dev(chan), "%s: dwidth: half word\n", __func__);
839	} else {
840		width = AT_XDMAC_CC_DWIDTH_BYTE;
841		dev_dbg(chan2dev(chan), "%s: dwidth: byte\n", __func__);
842	}
843
844	return width;
845}
846
847static struct at_xdmac_desc *
848at_xdmac_interleaved_queue_desc(struct dma_chan *chan,
849				struct at_xdmac_chan *atchan,
850				struct at_xdmac_desc *prev,
851				dma_addr_t src, dma_addr_t dst,
852				struct dma_interleaved_template *xt,
853				struct data_chunk *chunk)
854{
855	struct at_xdmac_desc	*desc;
856	u32			dwidth;
857	unsigned long		flags;
858	size_t			ublen;
859	/*
860	 * WARNING: The channel configuration is set here since there is no
861	 * dmaengine_slave_config call in this case. Moreover we don't know the
862	 * direction, it involves we can't dynamically set the source and dest
863	 * interface so we have to use the same one. Only interface 0 allows EBI
864	 * access. Hopefully we can access DDR through both ports (at least on
865	 * SAMA5D4x), so we can use the same interface for source and dest,
866	 * that solves the fact we don't know the direction.
867	 * ERRATA: Even if useless for memory transfers, the PERID has to not
868	 * match the one of another channel. If not, it could lead to spurious
869	 * flag status.
870	 */
871	u32			chan_cc = AT_XDMAC_CC_PERID(0x3f)
872					| AT_XDMAC_CC_DIF(0)
873					| AT_XDMAC_CC_SIF(0)
874					| AT_XDMAC_CC_MBSIZE_SIXTEEN
875					| AT_XDMAC_CC_TYPE_MEM_TRAN;
876
877	dwidth = at_xdmac_align_width(chan, src | dst | chunk->size);
878	if (chunk->size >= (AT_XDMAC_MBR_UBC_UBLEN_MAX << dwidth)) {
879		dev_dbg(chan2dev(chan),
880			"%s: chunk too big (%zu, max size %lu)...\n",
881			__func__, chunk->size,
882			AT_XDMAC_MBR_UBC_UBLEN_MAX << dwidth);
883		return NULL;
884	}
885
886	if (prev)
887		dev_dbg(chan2dev(chan),
888			"Adding items at the end of desc 0x%p\n", prev);
889
890	if (xt->src_inc) {
891		if (xt->src_sgl)
892			chan_cc |=  AT_XDMAC_CC_SAM_UBS_AM;
893		else
894			chan_cc |=  AT_XDMAC_CC_SAM_INCREMENTED_AM;
895	}
896
897	if (xt->dst_inc) {
898		if (xt->dst_sgl)
899			chan_cc |=  AT_XDMAC_CC_DAM_UBS_AM;
900		else
901			chan_cc |=  AT_XDMAC_CC_DAM_INCREMENTED_AM;
902	}
903
904	spin_lock_irqsave(&atchan->lock, flags);
905	desc = at_xdmac_get_desc(atchan);
906	spin_unlock_irqrestore(&atchan->lock, flags);
907	if (!desc) {
908		dev_err(chan2dev(chan), "can't get descriptor\n");
909		return NULL;
910	}
911
912	chan_cc |= AT_XDMAC_CC_DWIDTH(dwidth);
913
914	ublen = chunk->size >> dwidth;
915
916	desc->lld.mbr_sa = src;
917	desc->lld.mbr_da = dst;
918	desc->lld.mbr_sus = dmaengine_get_src_icg(xt, chunk);
919	desc->lld.mbr_dus = dmaengine_get_dst_icg(xt, chunk);
920
921	desc->lld.mbr_ubc = AT_XDMAC_MBR_UBC_NDV3
922		| AT_XDMAC_MBR_UBC_NDEN
923		| AT_XDMAC_MBR_UBC_NSEN
924		| ublen;
925	desc->lld.mbr_cfg = chan_cc;
926
927	dev_dbg(chan2dev(chan),
928		"%s: lld: mbr_sa=%pad, mbr_da=%pad, mbr_ubc=0x%08x, mbr_cfg=0x%08x\n",
929		__func__, &desc->lld.mbr_sa, &desc->lld.mbr_da,
930		desc->lld.mbr_ubc, desc->lld.mbr_cfg);
931
932	/* Chain lld. */
933	if (prev)
934		at_xdmac_queue_desc(chan, prev, desc);
935
936	return desc;
937}
938
939static struct dma_async_tx_descriptor *
940at_xdmac_prep_interleaved(struct dma_chan *chan,
941			  struct dma_interleaved_template *xt,
942			  unsigned long flags)
943{
944	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
945	struct at_xdmac_desc	*prev = NULL, *first = NULL;
946	dma_addr_t		dst_addr, src_addr;
947	size_t			src_skip = 0, dst_skip = 0, len = 0;
948	struct data_chunk	*chunk;
949	int			i;
950
951	if (!xt || !xt->numf || (xt->dir != DMA_MEM_TO_MEM))
952		return NULL;
953
954	/*
955	 * TODO: Handle the case where we have to repeat a chain of
956	 * descriptors...
957	 */
958	if ((xt->numf > 1) && (xt->frame_size > 1))
959		return NULL;
960
961	dev_dbg(chan2dev(chan), "%s: src=%pad, dest=%pad, numf=%zu, frame_size=%zu, flags=0x%lx\n",
962		__func__, &xt->src_start, &xt->dst_start,	xt->numf,
963		xt->frame_size, flags);
964
965	src_addr = xt->src_start;
966	dst_addr = xt->dst_start;
967
968	if (xt->numf > 1) {
969		first = at_xdmac_interleaved_queue_desc(chan, atchan,
970							NULL,
971							src_addr, dst_addr,
972							xt, xt->sgl);
973		if (!first)
974			return NULL;
975
976		/* Length of the block is (BLEN+1) microblocks. */
977		for (i = 0; i < xt->numf - 1; i++)
978			at_xdmac_increment_block_count(chan, first);
979
980		dev_dbg(chan2dev(chan), "%s: add desc 0x%p to descs_list 0x%p\n",
981			__func__, first, first);
982		list_add_tail(&first->desc_node, &first->descs_list);
983	} else {
984		for (i = 0; i < xt->frame_size; i++) {
985			size_t src_icg = 0, dst_icg = 0;
986			struct at_xdmac_desc *desc;
987
988			chunk = xt->sgl + i;
989
990			dst_icg = dmaengine_get_dst_icg(xt, chunk);
991			src_icg = dmaengine_get_src_icg(xt, chunk);
992
993			src_skip = chunk->size + src_icg;
994			dst_skip = chunk->size + dst_icg;
995
996			dev_dbg(chan2dev(chan),
997				"%s: chunk size=%zu, src icg=%zu, dst icg=%zu\n",
998				__func__, chunk->size, src_icg, dst_icg);
999
1000			desc = at_xdmac_interleaved_queue_desc(chan, atchan,
1001							       prev,
1002							       src_addr, dst_addr,
1003							       xt, chunk);
1004			if (!desc) {
1005				if (first)
1006					list_splice_tail_init(&first->descs_list,
1007							      &atchan->free_descs_list);
1008				return NULL;
1009			}
1010
1011			if (!first)
1012				first = desc;
1013
1014			dev_dbg(chan2dev(chan), "%s: add desc 0x%p to descs_list 0x%p\n",
1015				__func__, desc, first);
1016			list_add_tail(&desc->desc_node, &first->descs_list);
1017
1018			if (xt->src_sgl)
1019				src_addr += src_skip;
1020
1021			if (xt->dst_sgl)
1022				dst_addr += dst_skip;
1023
1024			len += chunk->size;
1025			prev = desc;
1026		}
1027	}
1028
1029	first->tx_dma_desc.cookie = -EBUSY;
1030	first->tx_dma_desc.flags = flags;
1031	first->xfer_size = len;
1032
1033	return &first->tx_dma_desc;
1034}
1035
1036static struct dma_async_tx_descriptor *
1037at_xdmac_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
1038			 size_t len, unsigned long flags)
1039{
1040	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
1041	struct at_xdmac_desc	*first = NULL, *prev = NULL;
1042	size_t			remaining_size = len, xfer_size = 0, ublen;
1043	dma_addr_t		src_addr = src, dst_addr = dest;
1044	u32			dwidth;
1045	/*
1046	 * WARNING: We don't know the direction, it involves we can't
1047	 * dynamically set the source and dest interface so we have to use the
1048	 * same one. Only interface 0 allows EBI access. Hopefully we can
1049	 * access DDR through both ports (at least on SAMA5D4x), so we can use
1050	 * the same interface for source and dest, that solves the fact we
1051	 * don't know the direction.
1052	 * ERRATA: Even if useless for memory transfers, the PERID has to not
1053	 * match the one of another channel. If not, it could lead to spurious
1054	 * flag status.
1055	 */
1056	u32			chan_cc = AT_XDMAC_CC_PERID(0x3f)
1057					| AT_XDMAC_CC_DAM_INCREMENTED_AM
1058					| AT_XDMAC_CC_SAM_INCREMENTED_AM
1059					| AT_XDMAC_CC_DIF(0)
1060					| AT_XDMAC_CC_SIF(0)
1061					| AT_XDMAC_CC_MBSIZE_SIXTEEN
1062					| AT_XDMAC_CC_TYPE_MEM_TRAN;
1063	unsigned long		irqflags;
1064
1065	dev_dbg(chan2dev(chan), "%s: src=%pad, dest=%pad, len=%zd, flags=0x%lx\n",
1066		__func__, &src, &dest, len, flags);
1067
1068	if (unlikely(!len))
1069		return NULL;
1070
1071	dwidth = at_xdmac_align_width(chan, src_addr | dst_addr);
1072
1073	/* Prepare descriptors. */
1074	while (remaining_size) {
1075		struct at_xdmac_desc	*desc = NULL;
1076
1077		dev_dbg(chan2dev(chan), "%s: remaining_size=%zu\n", __func__, remaining_size);
1078
1079		spin_lock_irqsave(&atchan->lock, irqflags);
1080		desc = at_xdmac_get_desc(atchan);
1081		spin_unlock_irqrestore(&atchan->lock, irqflags);
1082		if (!desc) {
1083			dev_err(chan2dev(chan), "can't get descriptor\n");
1084			if (first)
1085				list_splice_tail_init(&first->descs_list,
1086						      &atchan->free_descs_list);
1087			return NULL;
1088		}
1089
1090		/* Update src and dest addresses. */
1091		src_addr += xfer_size;
1092		dst_addr += xfer_size;
1093
1094		if (remaining_size >= AT_XDMAC_MBR_UBC_UBLEN_MAX << dwidth)
1095			xfer_size = AT_XDMAC_MBR_UBC_UBLEN_MAX << dwidth;
1096		else
1097			xfer_size = remaining_size;
1098
1099		dev_dbg(chan2dev(chan), "%s: xfer_size=%zu\n", __func__, xfer_size);
1100
1101		/* Check remaining length and change data width if needed. */
1102		dwidth = at_xdmac_align_width(chan,
1103					      src_addr | dst_addr | xfer_size);
1104		chan_cc &= ~AT_XDMAC_CC_DWIDTH_MASK;
1105		chan_cc |= AT_XDMAC_CC_DWIDTH(dwidth);
1106
1107		ublen = xfer_size >> dwidth;
1108		remaining_size -= xfer_size;
1109
1110		desc->lld.mbr_sa = src_addr;
1111		desc->lld.mbr_da = dst_addr;
1112		desc->lld.mbr_ubc = AT_XDMAC_MBR_UBC_NDV2
1113			| AT_XDMAC_MBR_UBC_NDEN
1114			| AT_XDMAC_MBR_UBC_NSEN
1115			| ublen;
1116		desc->lld.mbr_cfg = chan_cc;
1117
1118		dev_dbg(chan2dev(chan),
1119			 "%s: lld: mbr_sa=%pad, mbr_da=%pad, mbr_ubc=0x%08x, mbr_cfg=0x%08x\n",
1120			 __func__, &desc->lld.mbr_sa, &desc->lld.mbr_da, desc->lld.mbr_ubc, desc->lld.mbr_cfg);
1121
1122		/* Chain lld. */
1123		if (prev)
1124			at_xdmac_queue_desc(chan, prev, desc);
1125
1126		prev = desc;
1127		if (!first)
1128			first = desc;
1129
1130		dev_dbg(chan2dev(chan), "%s: add desc 0x%p to descs_list 0x%p\n",
1131			 __func__, desc, first);
1132		list_add_tail(&desc->desc_node, &first->descs_list);
1133	}
1134
1135	first->tx_dma_desc.flags = flags;
1136	first->xfer_size = len;
1137
1138	return &first->tx_dma_desc;
1139}
1140
1141static struct at_xdmac_desc *at_xdmac_memset_create_desc(struct dma_chan *chan,
1142							 struct at_xdmac_chan *atchan,
1143							 dma_addr_t dst_addr,
1144							 size_t len,
1145							 int value)
1146{
1147	struct at_xdmac_desc	*desc;
1148	unsigned long		flags;
1149	size_t			ublen;
1150	u32			dwidth;
1151	/*
1152	 * WARNING: The channel configuration is set here since there is no
1153	 * dmaengine_slave_config call in this case. Moreover we don't know the
1154	 * direction, it involves we can't dynamically set the source and dest
1155	 * interface so we have to use the same one. Only interface 0 allows EBI
1156	 * access. Hopefully we can access DDR through both ports (at least on
1157	 * SAMA5D4x), so we can use the same interface for source and dest,
1158	 * that solves the fact we don't know the direction.
1159	 * ERRATA: Even if useless for memory transfers, the PERID has to not
1160	 * match the one of another channel. If not, it could lead to spurious
1161	 * flag status.
1162	 */
1163	u32			chan_cc = AT_XDMAC_CC_PERID(0x3f)
1164					| AT_XDMAC_CC_DAM_UBS_AM
1165					| AT_XDMAC_CC_SAM_INCREMENTED_AM
1166					| AT_XDMAC_CC_DIF(0)
1167					| AT_XDMAC_CC_SIF(0)
1168					| AT_XDMAC_CC_MBSIZE_SIXTEEN
1169					| AT_XDMAC_CC_MEMSET_HW_MODE
1170					| AT_XDMAC_CC_TYPE_MEM_TRAN;
1171
1172	dwidth = at_xdmac_align_width(chan, dst_addr);
1173
1174	if (len >= (AT_XDMAC_MBR_UBC_UBLEN_MAX << dwidth)) {
1175		dev_err(chan2dev(chan),
1176			"%s: Transfer too large, aborting...\n",
1177			__func__);
1178		return NULL;
1179	}
1180
1181	spin_lock_irqsave(&atchan->lock, flags);
1182	desc = at_xdmac_get_desc(atchan);
1183	spin_unlock_irqrestore(&atchan->lock, flags);
1184	if (!desc) {
1185		dev_err(chan2dev(chan), "can't get descriptor\n");
1186		return NULL;
1187	}
1188
1189	chan_cc |= AT_XDMAC_CC_DWIDTH(dwidth);
1190
1191	ublen = len >> dwidth;
1192
1193	desc->lld.mbr_da = dst_addr;
1194	desc->lld.mbr_ds = value;
1195	desc->lld.mbr_ubc = AT_XDMAC_MBR_UBC_NDV3
1196		| AT_XDMAC_MBR_UBC_NDEN
1197		| AT_XDMAC_MBR_UBC_NSEN
1198		| ublen;
1199	desc->lld.mbr_cfg = chan_cc;
1200
1201	dev_dbg(chan2dev(chan),
1202		"%s: lld: mbr_da=%pad, mbr_ds=0x%08x, mbr_ubc=0x%08x, mbr_cfg=0x%08x\n",
1203		__func__, &desc->lld.mbr_da, desc->lld.mbr_ds, desc->lld.mbr_ubc,
1204		desc->lld.mbr_cfg);
1205
1206	return desc;
1207}
1208
1209static struct dma_async_tx_descriptor *
1210at_xdmac_prep_dma_memset(struct dma_chan *chan, dma_addr_t dest, int value,
1211			 size_t len, unsigned long flags)
1212{
1213	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
1214	struct at_xdmac_desc	*desc;
1215
1216	dev_dbg(chan2dev(chan), "%s: dest=%pad, len=%zu, pattern=0x%x, flags=0x%lx\n",
1217		__func__, &dest, len, value, flags);
1218
1219	if (unlikely(!len))
1220		return NULL;
1221
1222	desc = at_xdmac_memset_create_desc(chan, atchan, dest, len, value);
1223	list_add_tail(&desc->desc_node, &desc->descs_list);
1224
1225	desc->tx_dma_desc.cookie = -EBUSY;
1226	desc->tx_dma_desc.flags = flags;
1227	desc->xfer_size = len;
1228
1229	return &desc->tx_dma_desc;
1230}
1231
1232static struct dma_async_tx_descriptor *
1233at_xdmac_prep_dma_memset_sg(struct dma_chan *chan, struct scatterlist *sgl,
1234			    unsigned int sg_len, int value,
1235			    unsigned long flags)
1236{
1237	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
1238	struct at_xdmac_desc	*desc, *pdesc = NULL,
1239				*ppdesc = NULL, *first = NULL;
1240	struct scatterlist	*sg, *psg = NULL, *ppsg = NULL;
1241	size_t			stride = 0, pstride = 0, len = 0;
1242	int			i;
1243
1244	if (!sgl)
1245		return NULL;
1246
1247	dev_dbg(chan2dev(chan), "%s: sg_len=%d, value=0x%x, flags=0x%lx\n",
1248		__func__, sg_len, value, flags);
1249
1250	/* Prepare descriptors. */
1251	for_each_sg(sgl, sg, sg_len, i) {
1252		dev_dbg(chan2dev(chan), "%s: dest=%pad, len=%d, pattern=0x%x, flags=0x%lx\n",
1253			__func__, &sg_dma_address(sg), sg_dma_len(sg),
1254			value, flags);
1255		desc = at_xdmac_memset_create_desc(chan, atchan,
1256						   sg_dma_address(sg),
1257						   sg_dma_len(sg),
1258						   value);
1259		if (!desc && first)
1260			list_splice_tail_init(&first->descs_list,
1261					      &atchan->free_descs_list);
1262
1263		if (!first)
1264			first = desc;
1265
1266		/* Update our strides */
1267		pstride = stride;
1268		if (psg)
1269			stride = sg_dma_address(sg) -
1270				(sg_dma_address(psg) + sg_dma_len(psg));
1271
1272		/*
1273		 * The scatterlist API gives us only the address and
1274		 * length of each elements.
1275		 *
1276		 * Unfortunately, we don't have the stride, which we
1277		 * will need to compute.
1278		 *
1279		 * That make us end up in a situation like this one:
1280		 *    len    stride    len    stride    len
1281		 * +-------+        +-------+        +-------+
1282		 * |  N-2  |        |  N-1  |        |   N   |
1283		 * +-------+        +-------+        +-------+
1284		 *
1285		 * We need all these three elements (N-2, N-1 and N)
1286		 * to actually take the decision on whether we need to
1287		 * queue N-1 or reuse N-2.
1288		 *
1289		 * We will only consider N if it is the last element.
1290		 */
1291		if (ppdesc && pdesc) {
1292			if ((stride == pstride) &&
1293			    (sg_dma_len(ppsg) == sg_dma_len(psg))) {
1294				dev_dbg(chan2dev(chan),
1295					"%s: desc 0x%p can be merged with desc 0x%p\n",
1296					__func__, pdesc, ppdesc);
1297
1298				/*
1299				 * Increment the block count of the
1300				 * N-2 descriptor
1301				 */
1302				at_xdmac_increment_block_count(chan, ppdesc);
1303				ppdesc->lld.mbr_dus = stride;
1304
1305				/*
1306				 * Put back the N-1 descriptor in the
1307				 * free descriptor list
1308				 */
1309				list_add_tail(&pdesc->desc_node,
1310					      &atchan->free_descs_list);
1311
1312				/*
1313				 * Make our N-1 descriptor pointer
1314				 * point to the N-2 since they were
1315				 * actually merged.
1316				 */
1317				pdesc = ppdesc;
1318
1319			/*
1320			 * Rule out the case where we don't have
1321			 * pstride computed yet (our second sg
1322			 * element)
1323			 *
1324			 * We also want to catch the case where there
1325			 * would be a negative stride,
1326			 */
1327			} else if (pstride ||
1328				   sg_dma_address(sg) < sg_dma_address(psg)) {
1329				/*
1330				 * Queue the N-1 descriptor after the
1331				 * N-2
1332				 */
1333				at_xdmac_queue_desc(chan, ppdesc, pdesc);
1334
1335				/*
1336				 * Add the N-1 descriptor to the list
1337				 * of the descriptors used for this
1338				 * transfer
1339				 */
1340				list_add_tail(&desc->desc_node,
1341					      &first->descs_list);
1342				dev_dbg(chan2dev(chan),
1343					"%s: add desc 0x%p to descs_list 0x%p\n",
1344					__func__, desc, first);
1345			}
1346		}
1347
1348		/*
1349		 * If we are the last element, just see if we have the
1350		 * same size than the previous element.
1351		 *
1352		 * If so, we can merge it with the previous descriptor
1353		 * since we don't care about the stride anymore.
1354		 */
1355		if ((i == (sg_len - 1)) &&
1356		    sg_dma_len(psg) == sg_dma_len(sg)) {
1357			dev_dbg(chan2dev(chan),
1358				"%s: desc 0x%p can be merged with desc 0x%p\n",
1359				__func__, desc, pdesc);
1360
1361			/*
1362			 * Increment the block count of the N-1
1363			 * descriptor
1364			 */
1365			at_xdmac_increment_block_count(chan, pdesc);
1366			pdesc->lld.mbr_dus = stride;
1367
1368			/*
1369			 * Put back the N descriptor in the free
1370			 * descriptor list
1371			 */
1372			list_add_tail(&desc->desc_node,
1373				      &atchan->free_descs_list);
1374		}
1375
1376		/* Update our descriptors */
1377		ppdesc = pdesc;
1378		pdesc = desc;
1379
1380		/* Update our scatter pointers */
1381		ppsg = psg;
1382		psg = sg;
1383
1384		len += sg_dma_len(sg);
1385	}
1386
1387	first->tx_dma_desc.cookie = -EBUSY;
1388	first->tx_dma_desc.flags = flags;
1389	first->xfer_size = len;
1390
1391	return &first->tx_dma_desc;
1392}
1393
1394static enum dma_status
1395at_xdmac_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
1396		struct dma_tx_state *txstate)
1397{
1398	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
1399	struct at_xdmac		*atxdmac = to_at_xdmac(atchan->chan.device);
1400	struct at_xdmac_desc	*desc, *_desc, *iter;
1401	struct list_head	*descs_list;
1402	enum dma_status		ret;
1403	int			residue, retry;
1404	u32			cur_nda, check_nda, cur_ubc, mask, value;
1405	u8			dwidth = 0;
1406	unsigned long		flags;
1407	bool			initd;
1408
1409	ret = dma_cookie_status(chan, cookie, txstate);
1410	if (ret == DMA_COMPLETE)
1411		return ret;
1412
1413	if (!txstate)
1414		return ret;
1415
1416	spin_lock_irqsave(&atchan->lock, flags);
1417
1418	desc = list_first_entry(&atchan->xfers_list, struct at_xdmac_desc, xfer_node);
1419
1420	/*
1421	 * If the transfer has not been started yet, don't need to compute the
1422	 * residue, it's the transfer length.
1423	 */
1424	if (!desc->active_xfer) {
1425		dma_set_residue(txstate, desc->xfer_size);
1426		goto spin_unlock;
1427	}
1428
1429	residue = desc->xfer_size;
1430	/*
1431	 * Flush FIFO: only relevant when the transfer is source peripheral
1432	 * synchronized. Flush is needed before reading CUBC because data in
1433	 * the FIFO are not reported by CUBC. Reporting a residue of the
1434	 * transfer length while we have data in FIFO can cause issue.
1435	 * Usecase: atmel USART has a timeout which means I have received
1436	 * characters but there is no more character received for a while. On
1437	 * timeout, it requests the residue. If the data are in the DMA FIFO,
1438	 * we will return a residue of the transfer length. It means no data
1439	 * received. If an application is waiting for these data, it will hang
1440	 * since we won't have another USART timeout without receiving new
1441	 * data.
1442	 */
1443	mask = AT_XDMAC_CC_TYPE | AT_XDMAC_CC_DSYNC;
1444	value = AT_XDMAC_CC_TYPE_PER_TRAN | AT_XDMAC_CC_DSYNC_PER2MEM;
1445	if ((desc->lld.mbr_cfg & mask) == value) {
1446		at_xdmac_write(atxdmac, AT_XDMAC_GSWF, atchan->mask);
1447		while (!(at_xdmac_chan_read(atchan, AT_XDMAC_CIS) & AT_XDMAC_CIS_FIS))
1448			cpu_relax();
1449	}
1450
1451	/*
1452	 * The easiest way to compute the residue should be to pause the DMA
1453	 * but doing this can lead to miss some data as some devices don't
1454	 * have FIFO.
1455	 * We need to read several registers because:
1456	 * - DMA is running therefore a descriptor change is possible while
1457	 * reading these registers
1458	 * - When the block transfer is done, the value of the CUBC register
1459	 * is set to its initial value until the fetch of the next descriptor.
1460	 * This value will corrupt the residue calculation so we have to skip
1461	 * it.
1462	 *
1463	 * INITD --------                    ------------
1464	 *              |____________________|
1465	 *       _______________________  _______________
1466	 * NDA       @desc2             \/   @desc3
1467	 *       _______________________/\_______________
1468	 *       __________  ___________  _______________
1469	 * CUBC       0    \/ MAX desc1 \/  MAX desc2
1470	 *       __________/\___________/\_______________
1471	 *
1472	 * Since descriptors are aligned on 64 bits, we can assume that
1473	 * the update of NDA and CUBC is atomic.
1474	 * Memory barriers are used to ensure the read order of the registers.
1475	 * A max number of retries is set because unlikely it could never ends.
1476	 */
1477	for (retry = 0; retry < AT_XDMAC_RESIDUE_MAX_RETRIES; retry++) {
1478		check_nda = at_xdmac_chan_read(atchan, AT_XDMAC_CNDA) & 0xfffffffc;
1479		rmb();
1480		cur_ubc = at_xdmac_chan_read(atchan, AT_XDMAC_CUBC);
1481		rmb();
1482		initd = !!(at_xdmac_chan_read(atchan, AT_XDMAC_CC) & AT_XDMAC_CC_INITD);
1483		rmb();
1484		cur_nda = at_xdmac_chan_read(atchan, AT_XDMAC_CNDA) & 0xfffffffc;
1485		rmb();
1486
1487		if ((check_nda == cur_nda) && initd)
1488			break;
1489	}
1490
1491	if (unlikely(retry >= AT_XDMAC_RESIDUE_MAX_RETRIES)) {
1492		ret = DMA_ERROR;
1493		goto spin_unlock;
1494	}
1495
1496	/*
1497	 * Flush FIFO: only relevant when the transfer is source peripheral
1498	 * synchronized. Another flush is needed here because CUBC is updated
1499	 * when the controller sends the data write command. It can lead to
1500	 * report data that are not written in the memory or the device. The
1501	 * FIFO flush ensures that data are really written.
1502	 */
1503	if ((desc->lld.mbr_cfg & mask) == value) {
1504		at_xdmac_write(atxdmac, AT_XDMAC_GSWF, atchan->mask);
1505		while (!(at_xdmac_chan_read(atchan, AT_XDMAC_CIS) & AT_XDMAC_CIS_FIS))
1506			cpu_relax();
1507	}
1508
1509	/*
1510	 * Remove size of all microblocks already transferred and the current
1511	 * one. Then add the remaining size to transfer of the current
1512	 * microblock.
1513	 */
1514	descs_list = &desc->descs_list;
1515	list_for_each_entry_safe(iter, _desc, descs_list, desc_node) {
1516		dwidth = at_xdmac_get_dwidth(iter->lld.mbr_cfg);
1517		residue -= (iter->lld.mbr_ubc & 0xffffff) << dwidth;
1518		if ((iter->lld.mbr_nda & 0xfffffffc) == cur_nda) {
1519			desc = iter;
1520			break;
1521		}
1522	}
1523	residue += cur_ubc << dwidth;
1524
1525	dma_set_residue(txstate, residue);
1526
1527	dev_dbg(chan2dev(chan),
1528		 "%s: desc=0x%p, tx_dma_desc.phys=%pad, tx_status=%d, cookie=%d, residue=%d\n",
1529		 __func__, desc, &desc->tx_dma_desc.phys, ret, cookie, residue);
1530
1531spin_unlock:
1532	spin_unlock_irqrestore(&atchan->lock, flags);
1533	return ret;
1534}
1535
1536static void at_xdmac_advance_work(struct at_xdmac_chan *atchan)
1537{
1538	struct at_xdmac_desc	*desc;
1539
1540	/*
1541	 * If channel is enabled, do nothing, advance_work will be triggered
1542	 * after the interruption.
1543	 */
1544	if (!at_xdmac_chan_is_enabled(atchan) && !list_empty(&atchan->xfers_list)) {
1545		desc = list_first_entry(&atchan->xfers_list,
1546					struct at_xdmac_desc,
1547					xfer_node);
1548		dev_vdbg(chan2dev(&atchan->chan), "%s: desc 0x%p\n", __func__, desc);
1549		if (!desc->active_xfer)
1550			at_xdmac_start_xfer(atchan, desc);
1551	}
1552}
1553
1554static void at_xdmac_handle_cyclic(struct at_xdmac_chan *atchan)
1555{
1556	struct at_xdmac_desc		*desc;
1557	struct dma_async_tx_descriptor	*txd;
1558
1559	spin_lock_irq(&atchan->lock);
1560	if (list_empty(&atchan->xfers_list)) {
1561		spin_unlock_irq(&atchan->lock);
1562		return;
1563	}
1564	desc = list_first_entry(&atchan->xfers_list, struct at_xdmac_desc,
1565				xfer_node);
1566	spin_unlock_irq(&atchan->lock);
1567	txd = &desc->tx_dma_desc;
1568	if (txd->flags & DMA_PREP_INTERRUPT)
1569		dmaengine_desc_get_callback_invoke(txd, NULL);
1570}
1571
1572static void at_xdmac_handle_error(struct at_xdmac_chan *atchan)
1573{
1574	struct at_xdmac		*atxdmac = to_at_xdmac(atchan->chan.device);
1575	struct at_xdmac_desc	*bad_desc;
1576
1577	/*
1578	 * The descriptor currently at the head of the active list is
1579	 * broken. Since we don't have any way to report errors, we'll
1580	 * just have to scream loudly and try to continue with other
1581	 * descriptors queued (if any).
1582	 */
1583	if (atchan->irq_status & AT_XDMAC_CIS_RBEIS)
1584		dev_err(chan2dev(&atchan->chan), "read bus error!!!");
1585	if (atchan->irq_status & AT_XDMAC_CIS_WBEIS)
1586		dev_err(chan2dev(&atchan->chan), "write bus error!!!");
1587	if (atchan->irq_status & AT_XDMAC_CIS_ROIS)
1588		dev_err(chan2dev(&atchan->chan), "request overflow error!!!");
1589
1590	spin_lock_irq(&atchan->lock);
1591
1592	/* Channel must be disabled first as it's not done automatically */
1593	at_xdmac_write(atxdmac, AT_XDMAC_GD, atchan->mask);
1594	while (at_xdmac_read(atxdmac, AT_XDMAC_GS) & atchan->mask)
1595		cpu_relax();
1596
1597	bad_desc = list_first_entry(&atchan->xfers_list,
1598				    struct at_xdmac_desc,
1599				    xfer_node);
1600
1601	spin_unlock_irq(&atchan->lock);
1602
1603	/* Print bad descriptor's details if needed */
1604	dev_dbg(chan2dev(&atchan->chan),
1605		"%s: lld: mbr_sa=%pad, mbr_da=%pad, mbr_ubc=0x%08x\n",
1606		__func__, &bad_desc->lld.mbr_sa, &bad_desc->lld.mbr_da,
1607		bad_desc->lld.mbr_ubc);
1608
1609	/* Then continue with usual descriptor management */
1610}
1611
1612static void at_xdmac_tasklet(struct tasklet_struct *t)
1613{
1614	struct at_xdmac_chan	*atchan = from_tasklet(atchan, t, tasklet);
1615	struct at_xdmac_desc	*desc;
1616	u32			error_mask;
1617
1618	dev_dbg(chan2dev(&atchan->chan), "%s: status=0x%08x\n",
1619		__func__, atchan->irq_status);
1620
1621	error_mask = AT_XDMAC_CIS_RBEIS
1622		     | AT_XDMAC_CIS_WBEIS
1623		     | AT_XDMAC_CIS_ROIS;
1624
1625	if (at_xdmac_chan_is_cyclic(atchan)) {
1626		at_xdmac_handle_cyclic(atchan);
1627	} else if ((atchan->irq_status & AT_XDMAC_CIS_LIS)
1628		   || (atchan->irq_status & error_mask)) {
1629		struct dma_async_tx_descriptor  *txd;
1630
1631		if (atchan->irq_status & error_mask)
1632			at_xdmac_handle_error(atchan);
1633
1634		spin_lock_irq(&atchan->lock);
1635		desc = list_first_entry(&atchan->xfers_list,
1636					struct at_xdmac_desc,
1637					xfer_node);
1638		dev_vdbg(chan2dev(&atchan->chan), "%s: desc 0x%p\n", __func__, desc);
1639		if (!desc->active_xfer) {
1640			dev_err(chan2dev(&atchan->chan), "Xfer not active: exiting");
1641			spin_unlock_irq(&atchan->lock);
1642			return;
1643		}
1644
1645		txd = &desc->tx_dma_desc;
1646		dma_cookie_complete(txd);
1647		/* Remove the transfer from the transfer list. */
1648		list_del(&desc->xfer_node);
1649		spin_unlock_irq(&atchan->lock);
1650
1651		if (txd->flags & DMA_PREP_INTERRUPT)
1652			dmaengine_desc_get_callback_invoke(txd, NULL);
1653
1654		dma_run_dependencies(txd);
1655
1656		spin_lock_irq(&atchan->lock);
1657		/* Move the xfer descriptors into the free descriptors list. */
1658		list_splice_tail_init(&desc->descs_list,
1659				      &atchan->free_descs_list);
1660		at_xdmac_advance_work(atchan);
1661		spin_unlock_irq(&atchan->lock);
1662	}
1663}
1664
1665static irqreturn_t at_xdmac_interrupt(int irq, void *dev_id)
1666{
1667	struct at_xdmac		*atxdmac = (struct at_xdmac *)dev_id;
1668	struct at_xdmac_chan	*atchan;
1669	u32			imr, status, pending;
1670	u32			chan_imr, chan_status;
1671	int			i, ret = IRQ_NONE;
1672
1673	do {
1674		imr = at_xdmac_read(atxdmac, AT_XDMAC_GIM);
1675		status = at_xdmac_read(atxdmac, AT_XDMAC_GIS);
1676		pending = status & imr;
1677
1678		dev_vdbg(atxdmac->dma.dev,
1679			 "%s: status=0x%08x, imr=0x%08x, pending=0x%08x\n",
1680			 __func__, status, imr, pending);
1681
1682		if (!pending)
1683			break;
1684
1685		/* We have to find which channel has generated the interrupt. */
1686		for (i = 0; i < atxdmac->dma.chancnt; i++) {
1687			if (!((1 << i) & pending))
1688				continue;
1689
1690			atchan = &atxdmac->chan[i];
1691			chan_imr = at_xdmac_chan_read(atchan, AT_XDMAC_CIM);
1692			chan_status = at_xdmac_chan_read(atchan, AT_XDMAC_CIS);
1693			atchan->irq_status = chan_status & chan_imr;
1694			dev_vdbg(atxdmac->dma.dev,
1695				 "%s: chan%d: imr=0x%x, status=0x%x\n",
1696				 __func__, i, chan_imr, chan_status);
1697			dev_vdbg(chan2dev(&atchan->chan),
1698				 "%s: CC=0x%08x CNDA=0x%08x, CNDC=0x%08x, CSA=0x%08x, CDA=0x%08x, CUBC=0x%08x\n",
1699				 __func__,
1700				 at_xdmac_chan_read(atchan, AT_XDMAC_CC),
1701				 at_xdmac_chan_read(atchan, AT_XDMAC_CNDA),
1702				 at_xdmac_chan_read(atchan, AT_XDMAC_CNDC),
1703				 at_xdmac_chan_read(atchan, AT_XDMAC_CSA),
1704				 at_xdmac_chan_read(atchan, AT_XDMAC_CDA),
1705				 at_xdmac_chan_read(atchan, AT_XDMAC_CUBC));
1706
1707			if (atchan->irq_status & (AT_XDMAC_CIS_RBEIS | AT_XDMAC_CIS_WBEIS))
1708				at_xdmac_write(atxdmac, AT_XDMAC_GD, atchan->mask);
1709
1710			tasklet_schedule(&atchan->tasklet);
1711			ret = IRQ_HANDLED;
1712		}
1713
1714	} while (pending);
1715
1716	return ret;
1717}
1718
1719static void at_xdmac_issue_pending(struct dma_chan *chan)
1720{
1721	struct at_xdmac_chan *atchan = to_at_xdmac_chan(chan);
1722	unsigned long flags;
1723
1724	dev_dbg(chan2dev(&atchan->chan), "%s\n", __func__);
1725
1726	spin_lock_irqsave(&atchan->lock, flags);
1727	at_xdmac_advance_work(atchan);
1728	spin_unlock_irqrestore(&atchan->lock, flags);
1729
1730	return;
1731}
1732
1733static int at_xdmac_device_config(struct dma_chan *chan,
1734				  struct dma_slave_config *config)
1735{
1736	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
1737	int ret;
1738	unsigned long		flags;
1739
1740	dev_dbg(chan2dev(chan), "%s\n", __func__);
1741
1742	spin_lock_irqsave(&atchan->lock, flags);
1743	ret = at_xdmac_set_slave_config(chan, config);
1744	spin_unlock_irqrestore(&atchan->lock, flags);
1745
1746	return ret;
1747}
1748
1749static int at_xdmac_device_pause(struct dma_chan *chan)
1750{
1751	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
1752	struct at_xdmac		*atxdmac = to_at_xdmac(atchan->chan.device);
1753	unsigned long		flags;
1754
1755	dev_dbg(chan2dev(chan), "%s\n", __func__);
1756
1757	if (test_and_set_bit(AT_XDMAC_CHAN_IS_PAUSED, &atchan->status))
1758		return 0;
1759
1760	spin_lock_irqsave(&atchan->lock, flags);
1761	at_xdmac_write(atxdmac, AT_XDMAC_GRWS, atchan->mask);
1762	while (at_xdmac_chan_read(atchan, AT_XDMAC_CC)
1763	       & (AT_XDMAC_CC_WRIP | AT_XDMAC_CC_RDIP))
1764		cpu_relax();
1765	spin_unlock_irqrestore(&atchan->lock, flags);
1766
1767	return 0;
1768}
1769
1770static int at_xdmac_device_resume(struct dma_chan *chan)
1771{
1772	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
1773	struct at_xdmac		*atxdmac = to_at_xdmac(atchan->chan.device);
1774	unsigned long		flags;
1775
1776	dev_dbg(chan2dev(chan), "%s\n", __func__);
1777
1778	spin_lock_irqsave(&atchan->lock, flags);
1779	if (!at_xdmac_chan_is_paused(atchan)) {
1780		spin_unlock_irqrestore(&atchan->lock, flags);
1781		return 0;
1782	}
1783
1784	at_xdmac_write(atxdmac, AT_XDMAC_GRWR, atchan->mask);
1785	clear_bit(AT_XDMAC_CHAN_IS_PAUSED, &atchan->status);
1786	spin_unlock_irqrestore(&atchan->lock, flags);
1787
1788	return 0;
1789}
1790
1791static int at_xdmac_device_terminate_all(struct dma_chan *chan)
1792{
1793	struct at_xdmac_desc	*desc, *_desc;
1794	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
1795	struct at_xdmac		*atxdmac = to_at_xdmac(atchan->chan.device);
1796	unsigned long		flags;
1797
1798	dev_dbg(chan2dev(chan), "%s\n", __func__);
1799
1800	spin_lock_irqsave(&atchan->lock, flags);
1801	at_xdmac_write(atxdmac, AT_XDMAC_GD, atchan->mask);
1802	while (at_xdmac_read(atxdmac, AT_XDMAC_GS) & atchan->mask)
1803		cpu_relax();
1804
1805	/* Cancel all pending transfers. */
1806	list_for_each_entry_safe(desc, _desc, &atchan->xfers_list, xfer_node) {
1807		list_del(&desc->xfer_node);
1808		list_splice_tail_init(&desc->descs_list,
1809				      &atchan->free_descs_list);
1810	}
1811
1812	clear_bit(AT_XDMAC_CHAN_IS_PAUSED, &atchan->status);
1813	clear_bit(AT_XDMAC_CHAN_IS_CYCLIC, &atchan->status);
1814	spin_unlock_irqrestore(&atchan->lock, flags);
1815
1816	return 0;
1817}
1818
1819static int at_xdmac_alloc_chan_resources(struct dma_chan *chan)
1820{
1821	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
1822	struct at_xdmac_desc	*desc;
1823	int			i;
1824
1825	if (at_xdmac_chan_is_enabled(atchan)) {
1826		dev_err(chan2dev(chan),
1827			"can't allocate channel resources (channel enabled)\n");
1828		return -EIO;
1829	}
1830
1831	if (!list_empty(&atchan->free_descs_list)) {
1832		dev_err(chan2dev(chan),
1833			"can't allocate channel resources (channel not free from a previous use)\n");
1834		return -EIO;
1835	}
1836
1837	for (i = 0; i < init_nr_desc_per_channel; i++) {
1838		desc = at_xdmac_alloc_desc(chan, GFP_KERNEL);
1839		if (!desc) {
1840			if (i == 0) {
1841				dev_warn(chan2dev(chan),
1842					 "can't allocate any descriptors\n");
1843				return -EIO;
1844			}
1845			dev_warn(chan2dev(chan),
1846				"only %d descriptors have been allocated\n", i);
1847			break;
1848		}
1849		list_add_tail(&desc->desc_node, &atchan->free_descs_list);
1850	}
1851
1852	dma_cookie_init(chan);
1853
1854	dev_dbg(chan2dev(chan), "%s: allocated %d descriptors\n", __func__, i);
1855
1856	return i;
1857}
1858
1859static void at_xdmac_free_chan_resources(struct dma_chan *chan)
1860{
1861	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
1862	struct at_xdmac		*atxdmac = to_at_xdmac(chan->device);
1863	struct at_xdmac_desc	*desc, *_desc;
1864
1865	list_for_each_entry_safe(desc, _desc, &atchan->free_descs_list, desc_node) {
1866		dev_dbg(chan2dev(chan), "%s: freeing descriptor %p\n", __func__, desc);
1867		list_del(&desc->desc_node);
1868		dma_pool_free(atxdmac->at_xdmac_desc_pool, desc, desc->tx_dma_desc.phys);
1869	}
1870
1871	return;
1872}
1873
1874#ifdef CONFIG_PM
1875static int atmel_xdmac_prepare(struct device *dev)
1876{
1877	struct at_xdmac		*atxdmac = dev_get_drvdata(dev);
1878	struct dma_chan		*chan, *_chan;
1879
1880	list_for_each_entry_safe(chan, _chan, &atxdmac->dma.channels, device_node) {
1881		struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
1882
1883		/* Wait for transfer completion, except in cyclic case. */
1884		if (at_xdmac_chan_is_enabled(atchan) && !at_xdmac_chan_is_cyclic(atchan))
1885			return -EAGAIN;
1886	}
1887	return 0;
1888}
1889#else
1890#	define atmel_xdmac_prepare NULL
1891#endif
1892
1893#ifdef CONFIG_PM_SLEEP
1894static int atmel_xdmac_suspend(struct device *dev)
1895{
1896	struct at_xdmac		*atxdmac = dev_get_drvdata(dev);
1897	struct dma_chan		*chan, *_chan;
1898
1899	list_for_each_entry_safe(chan, _chan, &atxdmac->dma.channels, device_node) {
1900		struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
1901
1902		atchan->save_cc = at_xdmac_chan_read(atchan, AT_XDMAC_CC);
1903		if (at_xdmac_chan_is_cyclic(atchan)) {
1904			if (!at_xdmac_chan_is_paused(atchan))
1905				at_xdmac_device_pause(chan);
1906			atchan->save_cim = at_xdmac_chan_read(atchan, AT_XDMAC_CIM);
1907			atchan->save_cnda = at_xdmac_chan_read(atchan, AT_XDMAC_CNDA);
1908			atchan->save_cndc = at_xdmac_chan_read(atchan, AT_XDMAC_CNDC);
1909		}
1910	}
1911	atxdmac->save_gim = at_xdmac_read(atxdmac, AT_XDMAC_GIM);
1912	atxdmac->save_gs = at_xdmac_read(atxdmac, AT_XDMAC_GS);
1913
1914	at_xdmac_off(atxdmac);
1915	clk_disable_unprepare(atxdmac->clk);
1916	return 0;
1917}
1918
1919static int atmel_xdmac_resume(struct device *dev)
1920{
1921	struct at_xdmac		*atxdmac = dev_get_drvdata(dev);
1922	struct at_xdmac_chan	*atchan;
1923	struct dma_chan		*chan, *_chan;
1924	int			i;
1925	int ret;
1926
1927	ret = clk_prepare_enable(atxdmac->clk);
1928	if (ret)
1929		return ret;
1930
1931	/* Clear pending interrupts. */
1932	for (i = 0; i < atxdmac->dma.chancnt; i++) {
1933		atchan = &atxdmac->chan[i];
1934		while (at_xdmac_chan_read(atchan, AT_XDMAC_CIS))
1935			cpu_relax();
1936	}
1937
1938	at_xdmac_write(atxdmac, AT_XDMAC_GIE, atxdmac->save_gim);
1939	list_for_each_entry_safe(chan, _chan, &atxdmac->dma.channels, device_node) {
1940		atchan = to_at_xdmac_chan(chan);
1941		at_xdmac_chan_write(atchan, AT_XDMAC_CC, atchan->save_cc);
1942		if (at_xdmac_chan_is_cyclic(atchan)) {
1943			if (at_xdmac_chan_is_paused(atchan))
1944				at_xdmac_device_resume(chan);
1945			at_xdmac_chan_write(atchan, AT_XDMAC_CNDA, atchan->save_cnda);
1946			at_xdmac_chan_write(atchan, AT_XDMAC_CNDC, atchan->save_cndc);
1947			at_xdmac_chan_write(atchan, AT_XDMAC_CIE, atchan->save_cim);
1948			wmb();
1949			if (atxdmac->save_gs & atchan->mask)
1950				at_xdmac_write(atxdmac, AT_XDMAC_GE, atchan->mask);
1951		}
1952	}
1953	return 0;
1954}
1955#endif /* CONFIG_PM_SLEEP */
1956
1957static int at_xdmac_probe(struct platform_device *pdev)
1958{
1959	struct at_xdmac	*atxdmac;
1960	int		irq, size, nr_channels, i, ret;
1961	void __iomem	*base;
1962	u32		reg;
1963
1964	irq = platform_get_irq(pdev, 0);
1965	if (irq < 0)
1966		return irq;
1967
1968	base = devm_platform_ioremap_resource(pdev, 0);
1969	if (IS_ERR(base))
1970		return PTR_ERR(base);
1971
1972	/*
1973	 * Read number of xdmac channels, read helper function can't be used
1974	 * since atxdmac is not yet allocated and we need to know the number
1975	 * of channels to do the allocation.
1976	 */
1977	reg = readl_relaxed(base + AT_XDMAC_GTYPE);
1978	nr_channels = AT_XDMAC_NB_CH(reg);
1979	if (nr_channels > AT_XDMAC_MAX_CHAN) {
1980		dev_err(&pdev->dev, "invalid number of channels (%u)\n",
1981			nr_channels);
1982		return -EINVAL;
1983	}
1984
1985	size = sizeof(*atxdmac);
1986	size += nr_channels * sizeof(struct at_xdmac_chan);
1987	atxdmac = devm_kzalloc(&pdev->dev, size, GFP_KERNEL);
1988	if (!atxdmac) {
1989		dev_err(&pdev->dev, "can't allocate at_xdmac structure\n");
1990		return -ENOMEM;
1991	}
1992
1993	atxdmac->regs = base;
1994	atxdmac->irq = irq;
1995
1996	atxdmac->clk = devm_clk_get(&pdev->dev, "dma_clk");
1997	if (IS_ERR(atxdmac->clk)) {
1998		dev_err(&pdev->dev, "can't get dma_clk\n");
1999		return PTR_ERR(atxdmac->clk);
2000	}
2001
2002	/* Do not use dev res to prevent races with tasklet */
2003	ret = request_irq(atxdmac->irq, at_xdmac_interrupt, 0, "at_xdmac", atxdmac);
2004	if (ret) {
2005		dev_err(&pdev->dev, "can't request irq\n");
2006		return ret;
2007	}
2008
2009	ret = clk_prepare_enable(atxdmac->clk);
2010	if (ret) {
2011		dev_err(&pdev->dev, "can't prepare or enable clock\n");
2012		goto err_free_irq;
2013	}
2014
2015	atxdmac->at_xdmac_desc_pool =
2016		dmam_pool_create(dev_name(&pdev->dev), &pdev->dev,
2017				sizeof(struct at_xdmac_desc), 4, 0);
2018	if (!atxdmac->at_xdmac_desc_pool) {
2019		dev_err(&pdev->dev, "no memory for descriptors dma pool\n");
2020		ret = -ENOMEM;
2021		goto err_clk_disable;
2022	}
2023
2024	dma_cap_set(DMA_CYCLIC, atxdmac->dma.cap_mask);
2025	dma_cap_set(DMA_INTERLEAVE, atxdmac->dma.cap_mask);
2026	dma_cap_set(DMA_MEMCPY, atxdmac->dma.cap_mask);
2027	dma_cap_set(DMA_MEMSET, atxdmac->dma.cap_mask);
2028	dma_cap_set(DMA_MEMSET_SG, atxdmac->dma.cap_mask);
2029	dma_cap_set(DMA_SLAVE, atxdmac->dma.cap_mask);
2030	/*
2031	 * Without DMA_PRIVATE the driver is not able to allocate more than
2032	 * one channel, second allocation fails in private_candidate.
2033	 */
2034	dma_cap_set(DMA_PRIVATE, atxdmac->dma.cap_mask);
2035	atxdmac->dma.dev				= &pdev->dev;
2036	atxdmac->dma.device_alloc_chan_resources	= at_xdmac_alloc_chan_resources;
2037	atxdmac->dma.device_free_chan_resources		= at_xdmac_free_chan_resources;
2038	atxdmac->dma.device_tx_status			= at_xdmac_tx_status;
2039	atxdmac->dma.device_issue_pending		= at_xdmac_issue_pending;
2040	atxdmac->dma.device_prep_dma_cyclic		= at_xdmac_prep_dma_cyclic;
2041	atxdmac->dma.device_prep_interleaved_dma	= at_xdmac_prep_interleaved;
2042	atxdmac->dma.device_prep_dma_memcpy		= at_xdmac_prep_dma_memcpy;
2043	atxdmac->dma.device_prep_dma_memset		= at_xdmac_prep_dma_memset;
2044	atxdmac->dma.device_prep_dma_memset_sg		= at_xdmac_prep_dma_memset_sg;
2045	atxdmac->dma.device_prep_slave_sg		= at_xdmac_prep_slave_sg;
2046	atxdmac->dma.device_config			= at_xdmac_device_config;
2047	atxdmac->dma.device_pause			= at_xdmac_device_pause;
2048	atxdmac->dma.device_resume			= at_xdmac_device_resume;
2049	atxdmac->dma.device_terminate_all		= at_xdmac_device_terminate_all;
2050	atxdmac->dma.src_addr_widths = AT_XDMAC_DMA_BUSWIDTHS;
2051	atxdmac->dma.dst_addr_widths = AT_XDMAC_DMA_BUSWIDTHS;
2052	atxdmac->dma.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
2053	atxdmac->dma.residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
2054
2055	/* Disable all chans and interrupts. */
2056	at_xdmac_off(atxdmac);
2057
2058	/* Init channels. */
2059	INIT_LIST_HEAD(&atxdmac->dma.channels);
2060	for (i = 0; i < nr_channels; i++) {
2061		struct at_xdmac_chan *atchan = &atxdmac->chan[i];
2062
2063		atchan->chan.device = &atxdmac->dma;
2064		list_add_tail(&atchan->chan.device_node,
2065			      &atxdmac->dma.channels);
2066
2067		atchan->ch_regs = at_xdmac_chan_reg_base(atxdmac, i);
2068		atchan->mask = 1 << i;
2069
2070		spin_lock_init(&atchan->lock);
2071		INIT_LIST_HEAD(&atchan->xfers_list);
2072		INIT_LIST_HEAD(&atchan->free_descs_list);
2073		tasklet_setup(&atchan->tasklet, at_xdmac_tasklet);
2074
2075		/* Clear pending interrupts. */
2076		while (at_xdmac_chan_read(atchan, AT_XDMAC_CIS))
2077			cpu_relax();
2078	}
2079	platform_set_drvdata(pdev, atxdmac);
2080
2081	ret = dma_async_device_register(&atxdmac->dma);
2082	if (ret) {
2083		dev_err(&pdev->dev, "fail to register DMA engine device\n");
2084		goto err_clk_disable;
2085	}
2086
2087	ret = of_dma_controller_register(pdev->dev.of_node,
2088					 at_xdmac_xlate, atxdmac);
2089	if (ret) {
2090		dev_err(&pdev->dev, "could not register of dma controller\n");
2091		goto err_dma_unregister;
2092	}
2093
2094	dev_info(&pdev->dev, "%d channels, mapped at 0x%p\n",
2095		 nr_channels, atxdmac->regs);
2096
2097	return 0;
2098
2099err_dma_unregister:
2100	dma_async_device_unregister(&atxdmac->dma);
2101err_clk_disable:
2102	clk_disable_unprepare(atxdmac->clk);
2103err_free_irq:
2104	free_irq(atxdmac->irq, atxdmac);
2105	return ret;
2106}
2107
2108static int at_xdmac_remove(struct platform_device *pdev)
2109{
2110	struct at_xdmac	*atxdmac = (struct at_xdmac *)platform_get_drvdata(pdev);
2111	int		i;
2112
2113	at_xdmac_off(atxdmac);
2114	of_dma_controller_free(pdev->dev.of_node);
2115	dma_async_device_unregister(&atxdmac->dma);
2116	clk_disable_unprepare(atxdmac->clk);
2117
2118	free_irq(atxdmac->irq, atxdmac);
2119
2120	for (i = 0; i < atxdmac->dma.chancnt; i++) {
2121		struct at_xdmac_chan *atchan = &atxdmac->chan[i];
2122
2123		tasklet_kill(&atchan->tasklet);
2124		at_xdmac_free_chan_resources(&atchan->chan);
2125	}
2126
2127	return 0;
2128}
2129
2130static const struct dev_pm_ops atmel_xdmac_dev_pm_ops = {
2131	.prepare	= atmel_xdmac_prepare,
2132	SET_LATE_SYSTEM_SLEEP_PM_OPS(atmel_xdmac_suspend, atmel_xdmac_resume)
2133};
2134
2135static const struct of_device_id atmel_xdmac_dt_ids[] = {
2136	{
2137		.compatible = "atmel,sama5d4-dma",
2138	}, {
2139		/* sentinel */
2140	}
2141};
2142MODULE_DEVICE_TABLE(of, atmel_xdmac_dt_ids);
2143
2144static struct platform_driver at_xdmac_driver = {
2145	.probe		= at_xdmac_probe,
2146	.remove		= at_xdmac_remove,
2147	.driver = {
2148		.name		= "at_xdmac",
2149		.of_match_table	= of_match_ptr(atmel_xdmac_dt_ids),
2150		.pm		= &atmel_xdmac_dev_pm_ops,
2151	}
2152};
2153
2154static int __init at_xdmac_init(void)
2155{
2156	return platform_driver_probe(&at_xdmac_driver, at_xdmac_probe);
2157}
2158subsys_initcall(at_xdmac_init);
2159
2160MODULE_DESCRIPTION("Atmel Extended DMA Controller driver");
2161MODULE_AUTHOR("Ludovic Desroches <ludovic.desroches@atmel.com>");
2162MODULE_LICENSE("GPL");
2163