xref: /openbmc/linux/drivers/dma/at_xdmac.c (revision 9134211f)
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 #include <linux/pm_runtime.h>
25 
26 #include "dmaengine.h"
27 
28 /* Global registers */
29 #define AT_XDMAC_GTYPE		0x00	/* Global Type Register */
30 #define		AT_XDMAC_NB_CH(i)	(((i) & 0x1F) + 1)		/* Number of Channels Minus One */
31 #define		AT_XDMAC_FIFO_SZ(i)	(((i) >> 5) & 0x7FF)		/* Number of Bytes */
32 #define		AT_XDMAC_NB_REQ(i)	((((i) >> 16) & 0x3F) + 1)	/* Number of Peripheral Requests Minus One */
33 #define AT_XDMAC_GCFG		0x04	/* Global Configuration Register */
34 #define		AT_XDMAC_WRHP(i)		(((i) & 0xF) << 4)
35 #define		AT_XDMAC_WRMP(i)		(((i) & 0xF) << 8)
36 #define		AT_XDMAC_WRLP(i)		(((i) & 0xF) << 12)
37 #define		AT_XDMAC_RDHP(i)		(((i) & 0xF) << 16)
38 #define		AT_XDMAC_RDMP(i)		(((i) & 0xF) << 20)
39 #define		AT_XDMAC_RDLP(i)		(((i) & 0xF) << 24)
40 #define		AT_XDMAC_RDSG(i)		(((i) & 0xF) << 28)
41 #define AT_XDMAC_GCFG_M2M	(AT_XDMAC_RDLP(0xF) | AT_XDMAC_WRLP(0xF))
42 #define AT_XDMAC_GCFG_P2M	(AT_XDMAC_RDSG(0x1) | AT_XDMAC_RDHP(0x3) | \
43 				AT_XDMAC_WRHP(0x5))
44 #define AT_XDMAC_GWAC		0x08	/* Global Weighted Arbiter Configuration Register */
45 #define		AT_XDMAC_PW0(i)		(((i) & 0xF) << 0)
46 #define		AT_XDMAC_PW1(i)		(((i) & 0xF) << 4)
47 #define		AT_XDMAC_PW2(i)		(((i) & 0xF) << 8)
48 #define		AT_XDMAC_PW3(i)		(((i) & 0xF) << 12)
49 #define AT_XDMAC_GWAC_M2M	0
50 #define AT_XDMAC_GWAC_P2M	(AT_XDMAC_PW0(0xF) | AT_XDMAC_PW2(0xF))
51 
52 #define AT_XDMAC_GIE		0x0C	/* Global Interrupt Enable Register */
53 #define AT_XDMAC_GID		0x10	/* Global Interrupt Disable Register */
54 #define AT_XDMAC_GIM		0x14	/* Global Interrupt Mask Register */
55 #define AT_XDMAC_GIS		0x18	/* Global Interrupt Status Register */
56 #define AT_XDMAC_GE		0x1C	/* Global Channel Enable Register */
57 #define AT_XDMAC_GD		0x20	/* Global Channel Disable Register */
58 #define AT_XDMAC_GS		0x24	/* Global Channel Status Register */
59 #define AT_XDMAC_VERSION	0xFFC	/* XDMAC Version Register */
60 
61 /* Channel relative registers offsets */
62 #define AT_XDMAC_CIE		0x00	/* Channel Interrupt Enable Register */
63 #define		AT_XDMAC_CIE_BIE	BIT(0)	/* End of Block Interrupt Enable Bit */
64 #define		AT_XDMAC_CIE_LIE	BIT(1)	/* End of Linked List Interrupt Enable Bit */
65 #define		AT_XDMAC_CIE_DIE	BIT(2)	/* End of Disable Interrupt Enable Bit */
66 #define		AT_XDMAC_CIE_FIE	BIT(3)	/* End of Flush Interrupt Enable Bit */
67 #define		AT_XDMAC_CIE_RBEIE	BIT(4)	/* Read Bus Error Interrupt Enable Bit */
68 #define		AT_XDMAC_CIE_WBEIE	BIT(5)	/* Write Bus Error Interrupt Enable Bit */
69 #define		AT_XDMAC_CIE_ROIE	BIT(6)	/* Request Overflow Interrupt Enable Bit */
70 #define AT_XDMAC_CID		0x04	/* Channel Interrupt Disable Register */
71 #define		AT_XDMAC_CID_BID	BIT(0)	/* End of Block Interrupt Disable Bit */
72 #define		AT_XDMAC_CID_LID	BIT(1)	/* End of Linked List Interrupt Disable Bit */
73 #define		AT_XDMAC_CID_DID	BIT(2)	/* End of Disable Interrupt Disable Bit */
74 #define		AT_XDMAC_CID_FID	BIT(3)	/* End of Flush Interrupt Disable Bit */
75 #define		AT_XDMAC_CID_RBEID	BIT(4)	/* Read Bus Error Interrupt Disable Bit */
76 #define		AT_XDMAC_CID_WBEID	BIT(5)	/* Write Bus Error Interrupt Disable Bit */
77 #define		AT_XDMAC_CID_ROID	BIT(6)	/* Request Overflow Interrupt Disable Bit */
78 #define AT_XDMAC_CIM		0x08	/* Channel Interrupt Mask Register */
79 #define		AT_XDMAC_CIM_BIM	BIT(0)	/* End of Block Interrupt Mask Bit */
80 #define		AT_XDMAC_CIM_LIM	BIT(1)	/* End of Linked List Interrupt Mask Bit */
81 #define		AT_XDMAC_CIM_DIM	BIT(2)	/* End of Disable Interrupt Mask Bit */
82 #define		AT_XDMAC_CIM_FIM	BIT(3)	/* End of Flush Interrupt Mask Bit */
83 #define		AT_XDMAC_CIM_RBEIM	BIT(4)	/* Read Bus Error Interrupt Mask Bit */
84 #define		AT_XDMAC_CIM_WBEIM	BIT(5)	/* Write Bus Error Interrupt Mask Bit */
85 #define		AT_XDMAC_CIM_ROIM	BIT(6)	/* Request Overflow Interrupt Mask Bit */
86 #define AT_XDMAC_CIS		0x0C	/* Channel Interrupt Status Register */
87 #define		AT_XDMAC_CIS_BIS	BIT(0)	/* End of Block Interrupt Status Bit */
88 #define		AT_XDMAC_CIS_LIS	BIT(1)	/* End of Linked List Interrupt Status Bit */
89 #define		AT_XDMAC_CIS_DIS	BIT(2)	/* End of Disable Interrupt Status Bit */
90 #define		AT_XDMAC_CIS_FIS	BIT(3)	/* End of Flush Interrupt Status Bit */
91 #define		AT_XDMAC_CIS_RBEIS	BIT(4)	/* Read Bus Error Interrupt Status Bit */
92 #define		AT_XDMAC_CIS_WBEIS	BIT(5)	/* Write Bus Error Interrupt Status Bit */
93 #define		AT_XDMAC_CIS_ROIS	BIT(6)	/* Request Overflow Interrupt Status Bit */
94 #define AT_XDMAC_CSA		0x10	/* Channel Source Address Register */
95 #define AT_XDMAC_CDA		0x14	/* Channel Destination Address Register */
96 #define AT_XDMAC_CNDA		0x18	/* Channel Next Descriptor Address Register */
97 #define		AT_XDMAC_CNDA_NDAIF(i)	((i) & 0x1)			/* Channel x Next Descriptor Interface */
98 #define		AT_XDMAC_CNDA_NDA(i)	((i) & 0xfffffffc)		/* Channel x Next Descriptor Address */
99 #define AT_XDMAC_CNDC		0x1C	/* Channel Next Descriptor Control Register */
100 #define		AT_XDMAC_CNDC_NDE		(0x1 << 0)		/* Channel x Next Descriptor Enable */
101 #define		AT_XDMAC_CNDC_NDSUP		(0x1 << 1)		/* Channel x Next Descriptor Source Update */
102 #define		AT_XDMAC_CNDC_NDDUP		(0x1 << 2)		/* Channel x Next Descriptor Destination Update */
103 #define		AT_XDMAC_CNDC_NDVIEW_MASK	GENMASK(28, 27)
104 #define		AT_XDMAC_CNDC_NDVIEW_NDV0	(0x0 << 3)		/* Channel x Next Descriptor View 0 */
105 #define		AT_XDMAC_CNDC_NDVIEW_NDV1	(0x1 << 3)		/* Channel x Next Descriptor View 1 */
106 #define		AT_XDMAC_CNDC_NDVIEW_NDV2	(0x2 << 3)		/* Channel x Next Descriptor View 2 */
107 #define		AT_XDMAC_CNDC_NDVIEW_NDV3	(0x3 << 3)		/* Channel x Next Descriptor View 3 */
108 #define AT_XDMAC_CUBC		0x20	/* Channel Microblock Control Register */
109 #define AT_XDMAC_CBC		0x24	/* Channel Block Control Register */
110 #define AT_XDMAC_CC		0x28	/* Channel Configuration Register */
111 #define		AT_XDMAC_CC_TYPE	(0x1 << 0)	/* Channel Transfer Type */
112 #define			AT_XDMAC_CC_TYPE_MEM_TRAN	(0x0 << 0)	/* Memory to Memory Transfer */
113 #define			AT_XDMAC_CC_TYPE_PER_TRAN	(0x1 << 0)	/* Peripheral to Memory or Memory to Peripheral Transfer */
114 #define		AT_XDMAC_CC_MBSIZE_MASK	(0x3 << 1)
115 #define			AT_XDMAC_CC_MBSIZE_SINGLE	(0x0 << 1)
116 #define			AT_XDMAC_CC_MBSIZE_FOUR		(0x1 << 1)
117 #define			AT_XDMAC_CC_MBSIZE_EIGHT	(0x2 << 1)
118 #define			AT_XDMAC_CC_MBSIZE_SIXTEEN	(0x3 << 1)
119 #define		AT_XDMAC_CC_DSYNC	(0x1 << 4)	/* Channel Synchronization */
120 #define			AT_XDMAC_CC_DSYNC_PER2MEM	(0x0 << 4)
121 #define			AT_XDMAC_CC_DSYNC_MEM2PER	(0x1 << 4)
122 #define		AT_XDMAC_CC_PROT	(0x1 << 5)	/* Channel Protection */
123 #define			AT_XDMAC_CC_PROT_SEC		(0x0 << 5)
124 #define			AT_XDMAC_CC_PROT_UNSEC		(0x1 << 5)
125 #define		AT_XDMAC_CC_SWREQ	(0x1 << 6)	/* Channel Software Request Trigger */
126 #define			AT_XDMAC_CC_SWREQ_HWR_CONNECTED	(0x0 << 6)
127 #define			AT_XDMAC_CC_SWREQ_SWR_CONNECTED	(0x1 << 6)
128 #define		AT_XDMAC_CC_MEMSET	(0x1 << 7)	/* Channel Fill Block of memory */
129 #define			AT_XDMAC_CC_MEMSET_NORMAL_MODE	(0x0 << 7)
130 #define			AT_XDMAC_CC_MEMSET_HW_MODE	(0x1 << 7)
131 #define		AT_XDMAC_CC_CSIZE(i)	((0x7 & (i)) << 8)	/* Channel Chunk Size */
132 #define		AT_XDMAC_CC_DWIDTH_OFFSET	11
133 #define		AT_XDMAC_CC_DWIDTH_MASK	(0x3 << AT_XDMAC_CC_DWIDTH_OFFSET)
134 #define		AT_XDMAC_CC_DWIDTH(i)	((0x3 & (i)) << AT_XDMAC_CC_DWIDTH_OFFSET)	/* Channel Data Width */
135 #define			AT_XDMAC_CC_DWIDTH_BYTE		0x0
136 #define			AT_XDMAC_CC_DWIDTH_HALFWORD	0x1
137 #define			AT_XDMAC_CC_DWIDTH_WORD		0x2
138 #define			AT_XDMAC_CC_DWIDTH_DWORD	0x3
139 #define		AT_XDMAC_CC_SIF(i)	((0x1 & (i)) << 13)	/* Channel Source Interface Identifier */
140 #define		AT_XDMAC_CC_DIF(i)	((0x1 & (i)) << 14)	/* Channel Destination Interface Identifier */
141 #define		AT_XDMAC_CC_SAM_MASK	(0x3 << 16)	/* Channel Source Addressing Mode */
142 #define			AT_XDMAC_CC_SAM_FIXED_AM	(0x0 << 16)
143 #define			AT_XDMAC_CC_SAM_INCREMENTED_AM	(0x1 << 16)
144 #define			AT_XDMAC_CC_SAM_UBS_AM		(0x2 << 16)
145 #define			AT_XDMAC_CC_SAM_UBS_DS_AM	(0x3 << 16)
146 #define		AT_XDMAC_CC_DAM_MASK	(0x3 << 18)	/* Channel Source Addressing Mode */
147 #define			AT_XDMAC_CC_DAM_FIXED_AM	(0x0 << 18)
148 #define			AT_XDMAC_CC_DAM_INCREMENTED_AM	(0x1 << 18)
149 #define			AT_XDMAC_CC_DAM_UBS_AM		(0x2 << 18)
150 #define			AT_XDMAC_CC_DAM_UBS_DS_AM	(0x3 << 18)
151 #define		AT_XDMAC_CC_INITD	(0x1 << 21)	/* Channel Initialization Terminated (read only) */
152 #define			AT_XDMAC_CC_INITD_TERMINATED	(0x0 << 21)
153 #define			AT_XDMAC_CC_INITD_IN_PROGRESS	(0x1 << 21)
154 #define		AT_XDMAC_CC_RDIP	(0x1 << 22)	/* Read in Progress (read only) */
155 #define			AT_XDMAC_CC_RDIP_DONE		(0x0 << 22)
156 #define			AT_XDMAC_CC_RDIP_IN_PROGRESS	(0x1 << 22)
157 #define		AT_XDMAC_CC_WRIP	(0x1 << 23)	/* Write in Progress (read only) */
158 #define			AT_XDMAC_CC_WRIP_DONE		(0x0 << 23)
159 #define			AT_XDMAC_CC_WRIP_IN_PROGRESS	(0x1 << 23)
160 #define		AT_XDMAC_CC_PERID(i)	((0x7f & (i)) << 24)	/* Channel Peripheral Identifier */
161 #define AT_XDMAC_CDS_MSP	0x2C	/* Channel Data Stride Memory Set Pattern */
162 #define AT_XDMAC_CSUS		0x30	/* Channel Source Microblock Stride */
163 #define AT_XDMAC_CDUS		0x34	/* Channel Destination Microblock Stride */
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 #define AT_XDMAC_MAX_CSIZE	16	/* 16 data */
177 #define AT_XDMAC_MAX_DWIDTH	8	/* 64 bits */
178 #define AT_XDMAC_RESIDUE_MAX_RETRIES	5
179 
180 #define AT_XDMAC_DMA_BUSWIDTHS\
181 	(BIT(DMA_SLAVE_BUSWIDTH_UNDEFINED) |\
182 	BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |\
183 	BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |\
184 	BIT(DMA_SLAVE_BUSWIDTH_4_BYTES) |\
185 	BIT(DMA_SLAVE_BUSWIDTH_8_BYTES))
186 
187 enum atc_status {
188 	AT_XDMAC_CHAN_IS_CYCLIC = 0,
189 	AT_XDMAC_CHAN_IS_PAUSED,
190 	AT_XDMAC_CHAN_IS_PAUSED_INTERNAL,
191 };
192 
193 struct at_xdmac_layout {
194 	/* Global Channel Read Suspend Register */
195 	u8				grs;
196 	/* Global Write Suspend Register */
197 	u8				gws;
198 	/* Global Channel Read Write Suspend Register */
199 	u8				grws;
200 	/* Global Channel Read Write Resume Register */
201 	u8				grwr;
202 	/* Global Channel Software Request Register */
203 	u8				gswr;
204 	/* Global channel Software Request Status Register */
205 	u8				gsws;
206 	/* Global Channel Software Flush Request Register */
207 	u8				gswf;
208 	/* Channel reg base */
209 	u8				chan_cc_reg_base;
210 	/* Source/Destination Interface must be specified or not */
211 	bool				sdif;
212 	/* AXI queue priority configuration supported */
213 	bool				axi_config;
214 };
215 
216 /* ----- Channels ----- */
217 struct at_xdmac_chan {
218 	struct dma_chan			chan;
219 	void __iomem			*ch_regs;
220 	u32				mask;		/* Channel Mask */
221 	u32				cfg;		/* Channel Configuration Register */
222 	u8				perid;		/* Peripheral ID */
223 	u8				perif;		/* Peripheral Interface */
224 	u8				memif;		/* Memory Interface */
225 	u32				save_cc;
226 	u32				save_cim;
227 	u32				save_cnda;
228 	u32				save_cndc;
229 	u32				irq_status;
230 	unsigned long			status;
231 	struct tasklet_struct		tasklet;
232 	struct dma_slave_config		sconfig;
233 
234 	spinlock_t			lock;
235 
236 	struct list_head		xfers_list;
237 	struct list_head		free_descs_list;
238 };
239 
240 
241 /* ----- Controller ----- */
242 struct at_xdmac {
243 	struct dma_device	dma;
244 	void __iomem		*regs;
245 	struct device		*dev;
246 	int			irq;
247 	struct clk		*clk;
248 	u32			save_gim;
249 	u32			save_gs;
250 	struct dma_pool		*at_xdmac_desc_pool;
251 	const struct at_xdmac_layout	*layout;
252 	struct at_xdmac_chan	chan[];
253 };
254 
255 
256 /* ----- Descriptors ----- */
257 
258 /* Linked List Descriptor */
259 struct at_xdmac_lld {
260 	u32 mbr_nda;	/* Next Descriptor Member */
261 	u32 mbr_ubc;	/* Microblock Control Member */
262 	u32 mbr_sa;	/* Source Address Member */
263 	u32 mbr_da;	/* Destination Address Member */
264 	u32 mbr_cfg;	/* Configuration Register */
265 	u32 mbr_bc;	/* Block Control Register */
266 	u32 mbr_ds;	/* Data Stride Register */
267 	u32 mbr_sus;	/* Source Microblock Stride Register */
268 	u32 mbr_dus;	/* Destination Microblock Stride Register */
269 };
270 
271 /* 64-bit alignment needed to update CNDA and CUBC registers in an atomic way. */
272 struct at_xdmac_desc {
273 	struct at_xdmac_lld		lld;
274 	enum dma_transfer_direction	direction;
275 	struct dma_async_tx_descriptor	tx_dma_desc;
276 	struct list_head		desc_node;
277 	/* Following members are only used by the first descriptor */
278 	bool				active_xfer;
279 	unsigned int			xfer_size;
280 	struct list_head		descs_list;
281 	struct list_head		xfer_node;
282 } __aligned(sizeof(u64));
283 
284 static const struct at_xdmac_layout at_xdmac_sama5d4_layout = {
285 	.grs = 0x28,
286 	.gws = 0x2C,
287 	.grws = 0x30,
288 	.grwr = 0x34,
289 	.gswr = 0x38,
290 	.gsws = 0x3C,
291 	.gswf = 0x40,
292 	.chan_cc_reg_base = 0x50,
293 	.sdif = true,
294 	.axi_config = false,
295 };
296 
297 static const struct at_xdmac_layout at_xdmac_sama7g5_layout = {
298 	.grs = 0x30,
299 	.gws = 0x38,
300 	.grws = 0x40,
301 	.grwr = 0x44,
302 	.gswr = 0x48,
303 	.gsws = 0x4C,
304 	.gswf = 0x50,
305 	.chan_cc_reg_base = 0x60,
306 	.sdif = false,
307 	.axi_config = true,
308 };
309 
310 static inline void __iomem *at_xdmac_chan_reg_base(struct at_xdmac *atxdmac, unsigned int chan_nb)
311 {
312 	return atxdmac->regs + (atxdmac->layout->chan_cc_reg_base + chan_nb * 0x40);
313 }
314 
315 #define at_xdmac_read(atxdmac, reg) readl_relaxed((atxdmac)->regs + (reg))
316 #define at_xdmac_write(atxdmac, reg, value) \
317 	writel_relaxed((value), (atxdmac)->regs + (reg))
318 
319 #define at_xdmac_chan_read(atchan, reg) readl_relaxed((atchan)->ch_regs + (reg))
320 #define at_xdmac_chan_write(atchan, reg, value) writel_relaxed((value), (atchan)->ch_regs + (reg))
321 
322 static inline struct at_xdmac_chan *to_at_xdmac_chan(struct dma_chan *dchan)
323 {
324 	return container_of(dchan, struct at_xdmac_chan, chan);
325 }
326 
327 static struct device *chan2dev(struct dma_chan *chan)
328 {
329 	return &chan->dev->device;
330 }
331 
332 static inline struct at_xdmac *to_at_xdmac(struct dma_device *ddev)
333 {
334 	return container_of(ddev, struct at_xdmac, dma);
335 }
336 
337 static inline struct at_xdmac_desc *txd_to_at_desc(struct dma_async_tx_descriptor *txd)
338 {
339 	return container_of(txd, struct at_xdmac_desc, tx_dma_desc);
340 }
341 
342 static inline int at_xdmac_chan_is_cyclic(struct at_xdmac_chan *atchan)
343 {
344 	return test_bit(AT_XDMAC_CHAN_IS_CYCLIC, &atchan->status);
345 }
346 
347 static inline int at_xdmac_chan_is_paused(struct at_xdmac_chan *atchan)
348 {
349 	return test_bit(AT_XDMAC_CHAN_IS_PAUSED, &atchan->status);
350 }
351 
352 static inline int at_xdmac_chan_is_paused_internal(struct at_xdmac_chan *atchan)
353 {
354 	return test_bit(AT_XDMAC_CHAN_IS_PAUSED_INTERNAL, &atchan->status);
355 }
356 
357 static inline bool at_xdmac_chan_is_peripheral_xfer(u32 cfg)
358 {
359 	return cfg & AT_XDMAC_CC_TYPE_PER_TRAN;
360 }
361 
362 static inline u8 at_xdmac_get_dwidth(u32 cfg)
363 {
364 	return (cfg & AT_XDMAC_CC_DWIDTH_MASK) >> AT_XDMAC_CC_DWIDTH_OFFSET;
365 };
366 
367 static unsigned int init_nr_desc_per_channel = 64;
368 module_param(init_nr_desc_per_channel, uint, 0644);
369 MODULE_PARM_DESC(init_nr_desc_per_channel,
370 		 "initial descriptors per channel (default: 64)");
371 
372 
373 static void at_xdmac_runtime_suspend_descriptors(struct at_xdmac_chan *atchan)
374 {
375 	struct at_xdmac		*atxdmac = to_at_xdmac(atchan->chan.device);
376 	struct at_xdmac_desc	*desc, *_desc;
377 
378 	list_for_each_entry_safe(desc, _desc, &atchan->xfers_list, xfer_node) {
379 		if (!desc->active_xfer)
380 			continue;
381 
382 		pm_runtime_mark_last_busy(atxdmac->dev);
383 		pm_runtime_put_autosuspend(atxdmac->dev);
384 	}
385 }
386 
387 static int at_xdmac_runtime_resume_descriptors(struct at_xdmac_chan *atchan)
388 {
389 	struct at_xdmac		*atxdmac = to_at_xdmac(atchan->chan.device);
390 	struct at_xdmac_desc	*desc, *_desc;
391 	int			ret;
392 
393 	list_for_each_entry_safe(desc, _desc, &atchan->xfers_list, xfer_node) {
394 		if (!desc->active_xfer)
395 			continue;
396 
397 		ret = pm_runtime_resume_and_get(atxdmac->dev);
398 		if (ret < 0)
399 			return ret;
400 	}
401 
402 	return 0;
403 }
404 
405 static bool at_xdmac_chan_is_enabled(struct at_xdmac_chan *atchan)
406 {
407 	struct at_xdmac		*atxdmac = to_at_xdmac(atchan->chan.device);
408 	int			ret;
409 
410 	ret = pm_runtime_resume_and_get(atxdmac->dev);
411 	if (ret < 0)
412 		return false;
413 
414 	ret = !!(at_xdmac_chan_read(atchan, AT_XDMAC_GS) & atchan->mask);
415 
416 	pm_runtime_mark_last_busy(atxdmac->dev);
417 	pm_runtime_put_autosuspend(atxdmac->dev);
418 
419 	return ret;
420 }
421 
422 static void at_xdmac_off(struct at_xdmac *atxdmac, bool suspend_descriptors)
423 {
424 	struct dma_chan		*chan, *_chan;
425 	struct at_xdmac_chan	*atchan;
426 	int			ret;
427 
428 	ret = pm_runtime_resume_and_get(atxdmac->dev);
429 	if (ret < 0)
430 		return;
431 
432 	at_xdmac_write(atxdmac, AT_XDMAC_GD, -1L);
433 
434 	/* Wait that all chans are disabled. */
435 	while (at_xdmac_read(atxdmac, AT_XDMAC_GS))
436 		cpu_relax();
437 
438 	at_xdmac_write(atxdmac, AT_XDMAC_GID, -1L);
439 
440 	/* Decrement runtime PM ref counter for each active descriptor. */
441 	if (!list_empty(&atxdmac->dma.channels) && suspend_descriptors) {
442 		list_for_each_entry_safe(chan, _chan, &atxdmac->dma.channels,
443 					 device_node) {
444 			atchan = to_at_xdmac_chan(chan);
445 			at_xdmac_runtime_suspend_descriptors(atchan);
446 		}
447 	}
448 
449 	pm_runtime_mark_last_busy(atxdmac->dev);
450 	pm_runtime_put_autosuspend(atxdmac->dev);
451 }
452 
453 /* Call with lock hold. */
454 static void at_xdmac_start_xfer(struct at_xdmac_chan *atchan,
455 				struct at_xdmac_desc *first)
456 {
457 	struct at_xdmac	*atxdmac = to_at_xdmac(atchan->chan.device);
458 	u32		reg;
459 	int		ret;
460 
461 	ret = pm_runtime_resume_and_get(atxdmac->dev);
462 	if (ret < 0)
463 		return;
464 
465 	dev_vdbg(chan2dev(&atchan->chan), "%s: desc 0x%p\n", __func__, first);
466 
467 	/* Set transfer as active to not try to start it again. */
468 	first->active_xfer = true;
469 
470 	/* Tell xdmac where to get the first descriptor. */
471 	reg = AT_XDMAC_CNDA_NDA(first->tx_dma_desc.phys);
472 	if (atxdmac->layout->sdif)
473 		reg |= AT_XDMAC_CNDA_NDAIF(atchan->memif);
474 
475 	at_xdmac_chan_write(atchan, AT_XDMAC_CNDA, reg);
476 
477 	/*
478 	 * When doing non cyclic transfer we need to use the next
479 	 * descriptor view 2 since some fields of the configuration register
480 	 * depend on transfer size and src/dest addresses.
481 	 */
482 	if (at_xdmac_chan_is_cyclic(atchan))
483 		reg = AT_XDMAC_CNDC_NDVIEW_NDV1;
484 	else if ((first->lld.mbr_ubc &
485 		  AT_XDMAC_CNDC_NDVIEW_MASK) == AT_XDMAC_MBR_UBC_NDV3)
486 		reg = AT_XDMAC_CNDC_NDVIEW_NDV3;
487 	else
488 		reg = AT_XDMAC_CNDC_NDVIEW_NDV2;
489 	/*
490 	 * Even if the register will be updated from the configuration in the
491 	 * descriptor when using view 2 or higher, the PROT bit won't be set
492 	 * properly. This bit can be modified only by using the channel
493 	 * configuration register.
494 	 */
495 	at_xdmac_chan_write(atchan, AT_XDMAC_CC, first->lld.mbr_cfg);
496 
497 	reg |= AT_XDMAC_CNDC_NDDUP
498 	       | AT_XDMAC_CNDC_NDSUP
499 	       | AT_XDMAC_CNDC_NDE;
500 	at_xdmac_chan_write(atchan, AT_XDMAC_CNDC, reg);
501 
502 	dev_vdbg(chan2dev(&atchan->chan),
503 		 "%s: CC=0x%08x CNDA=0x%08x, CNDC=0x%08x, CSA=0x%08x, CDA=0x%08x, CUBC=0x%08x\n",
504 		 __func__, at_xdmac_chan_read(atchan, AT_XDMAC_CC),
505 		 at_xdmac_chan_read(atchan, AT_XDMAC_CNDA),
506 		 at_xdmac_chan_read(atchan, AT_XDMAC_CNDC),
507 		 at_xdmac_chan_read(atchan, AT_XDMAC_CSA),
508 		 at_xdmac_chan_read(atchan, AT_XDMAC_CDA),
509 		 at_xdmac_chan_read(atchan, AT_XDMAC_CUBC));
510 
511 	at_xdmac_chan_write(atchan, AT_XDMAC_CID, 0xffffffff);
512 	reg = AT_XDMAC_CIE_RBEIE | AT_XDMAC_CIE_WBEIE;
513 	/*
514 	 * Request Overflow Error is only for peripheral synchronized transfers
515 	 */
516 	if (at_xdmac_chan_is_peripheral_xfer(first->lld.mbr_cfg))
517 		reg |= AT_XDMAC_CIE_ROIE;
518 
519 	/*
520 	 * There is no end of list when doing cyclic dma, we need to get
521 	 * an interrupt after each periods.
522 	 */
523 	if (at_xdmac_chan_is_cyclic(atchan))
524 		at_xdmac_chan_write(atchan, AT_XDMAC_CIE,
525 				    reg | AT_XDMAC_CIE_BIE);
526 	else
527 		at_xdmac_chan_write(atchan, AT_XDMAC_CIE,
528 				    reg | AT_XDMAC_CIE_LIE);
529 	at_xdmac_write(atxdmac, AT_XDMAC_GIE, atchan->mask);
530 	dev_vdbg(chan2dev(&atchan->chan),
531 		 "%s: enable channel (0x%08x)\n", __func__, atchan->mask);
532 	wmb();
533 	at_xdmac_write(atxdmac, AT_XDMAC_GE, atchan->mask);
534 
535 	dev_vdbg(chan2dev(&atchan->chan),
536 		 "%s: CC=0x%08x CNDA=0x%08x, CNDC=0x%08x, CSA=0x%08x, CDA=0x%08x, CUBC=0x%08x\n",
537 		 __func__, at_xdmac_chan_read(atchan, AT_XDMAC_CC),
538 		 at_xdmac_chan_read(atchan, AT_XDMAC_CNDA),
539 		 at_xdmac_chan_read(atchan, AT_XDMAC_CNDC),
540 		 at_xdmac_chan_read(atchan, AT_XDMAC_CSA),
541 		 at_xdmac_chan_read(atchan, AT_XDMAC_CDA),
542 		 at_xdmac_chan_read(atchan, AT_XDMAC_CUBC));
543 }
544 
545 static dma_cookie_t at_xdmac_tx_submit(struct dma_async_tx_descriptor *tx)
546 {
547 	struct at_xdmac_desc	*desc = txd_to_at_desc(tx);
548 	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(tx->chan);
549 	dma_cookie_t		cookie;
550 	unsigned long		irqflags;
551 
552 	spin_lock_irqsave(&atchan->lock, irqflags);
553 	cookie = dma_cookie_assign(tx);
554 
555 	list_add_tail(&desc->xfer_node, &atchan->xfers_list);
556 	spin_unlock_irqrestore(&atchan->lock, irqflags);
557 
558 	dev_vdbg(chan2dev(tx->chan), "%s: atchan 0x%p, add desc 0x%p to xfers_list\n",
559 		 __func__, atchan, desc);
560 
561 	return cookie;
562 }
563 
564 static struct at_xdmac_desc *at_xdmac_alloc_desc(struct dma_chan *chan,
565 						 gfp_t gfp_flags)
566 {
567 	struct at_xdmac_desc	*desc;
568 	struct at_xdmac		*atxdmac = to_at_xdmac(chan->device);
569 	dma_addr_t		phys;
570 
571 	desc = dma_pool_zalloc(atxdmac->at_xdmac_desc_pool, gfp_flags, &phys);
572 	if (desc) {
573 		INIT_LIST_HEAD(&desc->descs_list);
574 		dma_async_tx_descriptor_init(&desc->tx_dma_desc, chan);
575 		desc->tx_dma_desc.tx_submit = at_xdmac_tx_submit;
576 		desc->tx_dma_desc.phys = phys;
577 	}
578 
579 	return desc;
580 }
581 
582 static void at_xdmac_init_used_desc(struct at_xdmac_desc *desc)
583 {
584 	memset(&desc->lld, 0, sizeof(desc->lld));
585 	INIT_LIST_HEAD(&desc->descs_list);
586 	desc->direction = DMA_TRANS_NONE;
587 	desc->xfer_size = 0;
588 	desc->active_xfer = false;
589 }
590 
591 /* Call must be protected by lock. */
592 static struct at_xdmac_desc *at_xdmac_get_desc(struct at_xdmac_chan *atchan)
593 {
594 	struct at_xdmac_desc *desc;
595 
596 	if (list_empty(&atchan->free_descs_list)) {
597 		desc = at_xdmac_alloc_desc(&atchan->chan, GFP_NOWAIT);
598 	} else {
599 		desc = list_first_entry(&atchan->free_descs_list,
600 					struct at_xdmac_desc, desc_node);
601 		list_del(&desc->desc_node);
602 		at_xdmac_init_used_desc(desc);
603 	}
604 
605 	return desc;
606 }
607 
608 static void at_xdmac_queue_desc(struct dma_chan *chan,
609 				struct at_xdmac_desc *prev,
610 				struct at_xdmac_desc *desc)
611 {
612 	if (!prev || !desc)
613 		return;
614 
615 	prev->lld.mbr_nda = desc->tx_dma_desc.phys;
616 	prev->lld.mbr_ubc |= AT_XDMAC_MBR_UBC_NDE;
617 
618 	dev_dbg(chan2dev(chan),	"%s: chain lld: prev=0x%p, mbr_nda=%pad\n",
619 		__func__, prev, &prev->lld.mbr_nda);
620 }
621 
622 static inline void at_xdmac_increment_block_count(struct dma_chan *chan,
623 						  struct at_xdmac_desc *desc)
624 {
625 	if (!desc)
626 		return;
627 
628 	desc->lld.mbr_bc++;
629 
630 	dev_dbg(chan2dev(chan),
631 		"%s: incrementing the block count of the desc 0x%p\n",
632 		__func__, desc);
633 }
634 
635 static struct dma_chan *at_xdmac_xlate(struct of_phandle_args *dma_spec,
636 				       struct of_dma *of_dma)
637 {
638 	struct at_xdmac		*atxdmac = of_dma->of_dma_data;
639 	struct at_xdmac_chan	*atchan;
640 	struct dma_chan		*chan;
641 	struct device		*dev = atxdmac->dma.dev;
642 
643 	if (dma_spec->args_count != 1) {
644 		dev_err(dev, "dma phandler args: bad number of args\n");
645 		return NULL;
646 	}
647 
648 	chan = dma_get_any_slave_channel(&atxdmac->dma);
649 	if (!chan) {
650 		dev_err(dev, "can't get a dma channel\n");
651 		return NULL;
652 	}
653 
654 	atchan = to_at_xdmac_chan(chan);
655 	atchan->memif = AT91_XDMAC_DT_GET_MEM_IF(dma_spec->args[0]);
656 	atchan->perif = AT91_XDMAC_DT_GET_PER_IF(dma_spec->args[0]);
657 	atchan->perid = AT91_XDMAC_DT_GET_PERID(dma_spec->args[0]);
658 	dev_dbg(dev, "chan dt cfg: memif=%u perif=%u perid=%u\n",
659 		 atchan->memif, atchan->perif, atchan->perid);
660 
661 	return chan;
662 }
663 
664 static int at_xdmac_compute_chan_conf(struct dma_chan *chan,
665 				      enum dma_transfer_direction direction)
666 {
667 	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
668 	struct at_xdmac		*atxdmac = to_at_xdmac(atchan->chan.device);
669 	int			csize, dwidth;
670 
671 	if (direction == DMA_DEV_TO_MEM) {
672 		atchan->cfg =
673 			AT91_XDMAC_DT_PERID(atchan->perid)
674 			| AT_XDMAC_CC_DAM_INCREMENTED_AM
675 			| AT_XDMAC_CC_SAM_FIXED_AM
676 			| AT_XDMAC_CC_SWREQ_HWR_CONNECTED
677 			| AT_XDMAC_CC_DSYNC_PER2MEM
678 			| AT_XDMAC_CC_MBSIZE_SIXTEEN
679 			| AT_XDMAC_CC_TYPE_PER_TRAN;
680 		if (atxdmac->layout->sdif)
681 			atchan->cfg |= AT_XDMAC_CC_DIF(atchan->memif) |
682 				       AT_XDMAC_CC_SIF(atchan->perif);
683 
684 		csize = ffs(atchan->sconfig.src_maxburst) - 1;
685 		if (csize < 0) {
686 			dev_err(chan2dev(chan), "invalid src maxburst value\n");
687 			return -EINVAL;
688 		}
689 		atchan->cfg |= AT_XDMAC_CC_CSIZE(csize);
690 		dwidth = ffs(atchan->sconfig.src_addr_width) - 1;
691 		if (dwidth < 0) {
692 			dev_err(chan2dev(chan), "invalid src addr width value\n");
693 			return -EINVAL;
694 		}
695 		atchan->cfg |= AT_XDMAC_CC_DWIDTH(dwidth);
696 	} else if (direction == DMA_MEM_TO_DEV) {
697 		atchan->cfg =
698 			AT91_XDMAC_DT_PERID(atchan->perid)
699 			| AT_XDMAC_CC_DAM_FIXED_AM
700 			| AT_XDMAC_CC_SAM_INCREMENTED_AM
701 			| AT_XDMAC_CC_SWREQ_HWR_CONNECTED
702 			| AT_XDMAC_CC_DSYNC_MEM2PER
703 			| AT_XDMAC_CC_MBSIZE_SIXTEEN
704 			| AT_XDMAC_CC_TYPE_PER_TRAN;
705 		if (atxdmac->layout->sdif)
706 			atchan->cfg |= AT_XDMAC_CC_DIF(atchan->perif) |
707 				       AT_XDMAC_CC_SIF(atchan->memif);
708 
709 		csize = ffs(atchan->sconfig.dst_maxburst) - 1;
710 		if (csize < 0) {
711 			dev_err(chan2dev(chan), "invalid src maxburst value\n");
712 			return -EINVAL;
713 		}
714 		atchan->cfg |= AT_XDMAC_CC_CSIZE(csize);
715 		dwidth = ffs(atchan->sconfig.dst_addr_width) - 1;
716 		if (dwidth < 0) {
717 			dev_err(chan2dev(chan), "invalid dst addr width value\n");
718 			return -EINVAL;
719 		}
720 		atchan->cfg |= AT_XDMAC_CC_DWIDTH(dwidth);
721 	}
722 
723 	dev_dbg(chan2dev(chan),	"%s: cfg=0x%08x\n", __func__, atchan->cfg);
724 
725 	return 0;
726 }
727 
728 /*
729  * Only check that maxburst and addr width values are supported by
730  * the controller but not that the configuration is good to perform the
731  * transfer since we don't know the direction at this stage.
732  */
733 static int at_xdmac_check_slave_config(struct dma_slave_config *sconfig)
734 {
735 	if ((sconfig->src_maxburst > AT_XDMAC_MAX_CSIZE)
736 	    || (sconfig->dst_maxburst > AT_XDMAC_MAX_CSIZE))
737 		return -EINVAL;
738 
739 	if ((sconfig->src_addr_width > AT_XDMAC_MAX_DWIDTH)
740 	    || (sconfig->dst_addr_width > AT_XDMAC_MAX_DWIDTH))
741 		return -EINVAL;
742 
743 	return 0;
744 }
745 
746 static int at_xdmac_set_slave_config(struct dma_chan *chan,
747 				      struct dma_slave_config *sconfig)
748 {
749 	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
750 
751 	if (at_xdmac_check_slave_config(sconfig)) {
752 		dev_err(chan2dev(chan), "invalid slave configuration\n");
753 		return -EINVAL;
754 	}
755 
756 	memcpy(&atchan->sconfig, sconfig, sizeof(atchan->sconfig));
757 
758 	return 0;
759 }
760 
761 static struct dma_async_tx_descriptor *
762 at_xdmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
763 		       unsigned int sg_len, enum dma_transfer_direction direction,
764 		       unsigned long flags, void *context)
765 {
766 	struct at_xdmac_chan		*atchan = to_at_xdmac_chan(chan);
767 	struct at_xdmac_desc		*first = NULL, *prev = NULL;
768 	struct scatterlist		*sg;
769 	int				i;
770 	unsigned int			xfer_size = 0;
771 	unsigned long			irqflags;
772 	struct dma_async_tx_descriptor	*ret = NULL;
773 
774 	if (!sgl)
775 		return NULL;
776 
777 	if (!is_slave_direction(direction)) {
778 		dev_err(chan2dev(chan), "invalid DMA direction\n");
779 		return NULL;
780 	}
781 
782 	dev_dbg(chan2dev(chan), "%s: sg_len=%d, dir=%s, flags=0x%lx\n",
783 		 __func__, sg_len,
784 		 direction == DMA_MEM_TO_DEV ? "to device" : "from device",
785 		 flags);
786 
787 	/* Protect dma_sconfig field that can be modified by set_slave_conf. */
788 	spin_lock_irqsave(&atchan->lock, irqflags);
789 
790 	if (at_xdmac_compute_chan_conf(chan, direction))
791 		goto spin_unlock;
792 
793 	/* Prepare descriptors. */
794 	for_each_sg(sgl, sg, sg_len, i) {
795 		struct at_xdmac_desc	*desc = NULL;
796 		u32			len, mem, dwidth, fixed_dwidth;
797 
798 		len = sg_dma_len(sg);
799 		mem = sg_dma_address(sg);
800 		if (unlikely(!len)) {
801 			dev_err(chan2dev(chan), "sg data length is zero\n");
802 			goto spin_unlock;
803 		}
804 		dev_dbg(chan2dev(chan), "%s: * sg%d len=%u, mem=0x%08x\n",
805 			 __func__, i, len, mem);
806 
807 		desc = at_xdmac_get_desc(atchan);
808 		if (!desc) {
809 			dev_err(chan2dev(chan), "can't get descriptor\n");
810 			if (first)
811 				list_splice_tail_init(&first->descs_list,
812 						      &atchan->free_descs_list);
813 			goto spin_unlock;
814 		}
815 
816 		/* Linked list descriptor setup. */
817 		if (direction == DMA_DEV_TO_MEM) {
818 			desc->lld.mbr_sa = atchan->sconfig.src_addr;
819 			desc->lld.mbr_da = mem;
820 		} else {
821 			desc->lld.mbr_sa = mem;
822 			desc->lld.mbr_da = atchan->sconfig.dst_addr;
823 		}
824 		dwidth = at_xdmac_get_dwidth(atchan->cfg);
825 		fixed_dwidth = IS_ALIGNED(len, 1 << dwidth)
826 			       ? dwidth
827 			       : AT_XDMAC_CC_DWIDTH_BYTE;
828 		desc->lld.mbr_ubc = AT_XDMAC_MBR_UBC_NDV2			/* next descriptor view */
829 			| AT_XDMAC_MBR_UBC_NDEN					/* next descriptor dst parameter update */
830 			| AT_XDMAC_MBR_UBC_NSEN					/* next descriptor src parameter update */
831 			| (len >> fixed_dwidth);				/* microblock length */
832 		desc->lld.mbr_cfg = (atchan->cfg & ~AT_XDMAC_CC_DWIDTH_MASK) |
833 				    AT_XDMAC_CC_DWIDTH(fixed_dwidth);
834 		dev_dbg(chan2dev(chan),
835 			 "%s: lld: mbr_sa=%pad, mbr_da=%pad, mbr_ubc=0x%08x\n",
836 			 __func__, &desc->lld.mbr_sa, &desc->lld.mbr_da, desc->lld.mbr_ubc);
837 
838 		/* Chain lld. */
839 		if (prev)
840 			at_xdmac_queue_desc(chan, prev, desc);
841 
842 		prev = desc;
843 		if (!first)
844 			first = desc;
845 
846 		dev_dbg(chan2dev(chan), "%s: add desc 0x%p to descs_list 0x%p\n",
847 			 __func__, desc, first);
848 		list_add_tail(&desc->desc_node, &first->descs_list);
849 		xfer_size += len;
850 	}
851 
852 
853 	first->tx_dma_desc.flags = flags;
854 	first->xfer_size = xfer_size;
855 	first->direction = direction;
856 	ret = &first->tx_dma_desc;
857 
858 spin_unlock:
859 	spin_unlock_irqrestore(&atchan->lock, irqflags);
860 	return ret;
861 }
862 
863 static struct dma_async_tx_descriptor *
864 at_xdmac_prep_dma_cyclic(struct dma_chan *chan, dma_addr_t buf_addr,
865 			 size_t buf_len, size_t period_len,
866 			 enum dma_transfer_direction direction,
867 			 unsigned long flags)
868 {
869 	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
870 	struct at_xdmac_desc	*first = NULL, *prev = NULL;
871 	unsigned int		periods = buf_len / period_len;
872 	int			i;
873 	unsigned long		irqflags;
874 
875 	dev_dbg(chan2dev(chan), "%s: buf_addr=%pad, buf_len=%zd, period_len=%zd, dir=%s, flags=0x%lx\n",
876 		__func__, &buf_addr, buf_len, period_len,
877 		direction == DMA_MEM_TO_DEV ? "mem2per" : "per2mem", flags);
878 
879 	if (!is_slave_direction(direction)) {
880 		dev_err(chan2dev(chan), "invalid DMA direction\n");
881 		return NULL;
882 	}
883 
884 	if (test_and_set_bit(AT_XDMAC_CHAN_IS_CYCLIC, &atchan->status)) {
885 		dev_err(chan2dev(chan), "channel currently used\n");
886 		return NULL;
887 	}
888 
889 	if (at_xdmac_compute_chan_conf(chan, direction))
890 		return NULL;
891 
892 	for (i = 0; i < periods; i++) {
893 		struct at_xdmac_desc	*desc = NULL;
894 
895 		spin_lock_irqsave(&atchan->lock, irqflags);
896 		desc = at_xdmac_get_desc(atchan);
897 		if (!desc) {
898 			dev_err(chan2dev(chan), "can't get descriptor\n");
899 			if (first)
900 				list_splice_tail_init(&first->descs_list,
901 						      &atchan->free_descs_list);
902 			spin_unlock_irqrestore(&atchan->lock, irqflags);
903 			return NULL;
904 		}
905 		spin_unlock_irqrestore(&atchan->lock, irqflags);
906 		dev_dbg(chan2dev(chan),
907 			"%s: desc=0x%p, tx_dma_desc.phys=%pad\n",
908 			__func__, desc, &desc->tx_dma_desc.phys);
909 
910 		if (direction == DMA_DEV_TO_MEM) {
911 			desc->lld.mbr_sa = atchan->sconfig.src_addr;
912 			desc->lld.mbr_da = buf_addr + i * period_len;
913 		} else {
914 			desc->lld.mbr_sa = buf_addr + i * period_len;
915 			desc->lld.mbr_da = atchan->sconfig.dst_addr;
916 		}
917 		desc->lld.mbr_cfg = atchan->cfg;
918 		desc->lld.mbr_ubc = AT_XDMAC_MBR_UBC_NDV1
919 			| AT_XDMAC_MBR_UBC_NDEN
920 			| AT_XDMAC_MBR_UBC_NSEN
921 			| period_len >> at_xdmac_get_dwidth(desc->lld.mbr_cfg);
922 
923 		dev_dbg(chan2dev(chan),
924 			 "%s: lld: mbr_sa=%pad, mbr_da=%pad, mbr_ubc=0x%08x\n",
925 			 __func__, &desc->lld.mbr_sa, &desc->lld.mbr_da, desc->lld.mbr_ubc);
926 
927 		/* Chain lld. */
928 		if (prev)
929 			at_xdmac_queue_desc(chan, prev, desc);
930 
931 		prev = desc;
932 		if (!first)
933 			first = desc;
934 
935 		dev_dbg(chan2dev(chan), "%s: add desc 0x%p to descs_list 0x%p\n",
936 			 __func__, desc, first);
937 		list_add_tail(&desc->desc_node, &first->descs_list);
938 	}
939 
940 	at_xdmac_queue_desc(chan, prev, first);
941 	first->tx_dma_desc.flags = flags;
942 	first->xfer_size = buf_len;
943 	first->direction = direction;
944 
945 	return &first->tx_dma_desc;
946 }
947 
948 static inline u32 at_xdmac_align_width(struct dma_chan *chan, dma_addr_t addr)
949 {
950 	u32 width;
951 
952 	/*
953 	 * Check address alignment to select the greater data width we
954 	 * can use.
955 	 *
956 	 * Some XDMAC implementations don't provide dword transfer, in
957 	 * this case selecting dword has the same behavior as
958 	 * selecting word transfers.
959 	 */
960 	if (!(addr & 7)) {
961 		width = AT_XDMAC_CC_DWIDTH_DWORD;
962 		dev_dbg(chan2dev(chan), "%s: dwidth: double word\n", __func__);
963 	} else if (!(addr & 3)) {
964 		width = AT_XDMAC_CC_DWIDTH_WORD;
965 		dev_dbg(chan2dev(chan), "%s: dwidth: word\n", __func__);
966 	} else if (!(addr & 1)) {
967 		width = AT_XDMAC_CC_DWIDTH_HALFWORD;
968 		dev_dbg(chan2dev(chan), "%s: dwidth: half word\n", __func__);
969 	} else {
970 		width = AT_XDMAC_CC_DWIDTH_BYTE;
971 		dev_dbg(chan2dev(chan), "%s: dwidth: byte\n", __func__);
972 	}
973 
974 	return width;
975 }
976 
977 static struct at_xdmac_desc *
978 at_xdmac_interleaved_queue_desc(struct dma_chan *chan,
979 				struct at_xdmac_chan *atchan,
980 				struct at_xdmac_desc *prev,
981 				dma_addr_t src, dma_addr_t dst,
982 				struct dma_interleaved_template *xt,
983 				struct data_chunk *chunk)
984 {
985 	struct at_xdmac_desc	*desc;
986 	u32			dwidth;
987 	unsigned long		flags;
988 	size_t			ublen;
989 	/*
990 	 * WARNING: The channel configuration is set here since there is no
991 	 * dmaengine_slave_config call in this case. Moreover we don't know the
992 	 * direction, it involves we can't dynamically set the source and dest
993 	 * interface so we have to use the same one. Only interface 0 allows EBI
994 	 * access. Hopefully we can access DDR through both ports (at least on
995 	 * SAMA5D4x), so we can use the same interface for source and dest,
996 	 * that solves the fact we don't know the direction.
997 	 * ERRATA: Even if useless for memory transfers, the PERID has to not
998 	 * match the one of another channel. If not, it could lead to spurious
999 	 * flag status.
1000 	 * For SAMA7G5x case, the SIF and DIF fields are no longer used.
1001 	 * Thus, no need to have the SIF/DIF interfaces here.
1002 	 * For SAMA5D4x and SAMA5D2x the SIF and DIF are already configured as
1003 	 * zero.
1004 	 */
1005 	u32			chan_cc = AT_XDMAC_CC_PERID(0x7f)
1006 					| AT_XDMAC_CC_MBSIZE_SIXTEEN
1007 					| AT_XDMAC_CC_TYPE_MEM_TRAN;
1008 
1009 	dwidth = at_xdmac_align_width(chan, src | dst | chunk->size);
1010 	if (chunk->size >= (AT_XDMAC_MBR_UBC_UBLEN_MAX << dwidth)) {
1011 		dev_dbg(chan2dev(chan),
1012 			"%s: chunk too big (%zu, max size %lu)...\n",
1013 			__func__, chunk->size,
1014 			AT_XDMAC_MBR_UBC_UBLEN_MAX << dwidth);
1015 		return NULL;
1016 	}
1017 
1018 	if (prev)
1019 		dev_dbg(chan2dev(chan),
1020 			"Adding items at the end of desc 0x%p\n", prev);
1021 
1022 	if (xt->src_inc) {
1023 		if (xt->src_sgl)
1024 			chan_cc |=  AT_XDMAC_CC_SAM_UBS_AM;
1025 		else
1026 			chan_cc |=  AT_XDMAC_CC_SAM_INCREMENTED_AM;
1027 	}
1028 
1029 	if (xt->dst_inc) {
1030 		if (xt->dst_sgl)
1031 			chan_cc |=  AT_XDMAC_CC_DAM_UBS_AM;
1032 		else
1033 			chan_cc |=  AT_XDMAC_CC_DAM_INCREMENTED_AM;
1034 	}
1035 
1036 	spin_lock_irqsave(&atchan->lock, flags);
1037 	desc = at_xdmac_get_desc(atchan);
1038 	spin_unlock_irqrestore(&atchan->lock, flags);
1039 	if (!desc) {
1040 		dev_err(chan2dev(chan), "can't get descriptor\n");
1041 		return NULL;
1042 	}
1043 
1044 	chan_cc |= AT_XDMAC_CC_DWIDTH(dwidth);
1045 
1046 	ublen = chunk->size >> dwidth;
1047 
1048 	desc->lld.mbr_sa = src;
1049 	desc->lld.mbr_da = dst;
1050 	desc->lld.mbr_sus = dmaengine_get_src_icg(xt, chunk);
1051 	desc->lld.mbr_dus = dmaengine_get_dst_icg(xt, chunk);
1052 
1053 	desc->lld.mbr_ubc = AT_XDMAC_MBR_UBC_NDV3
1054 		| AT_XDMAC_MBR_UBC_NDEN
1055 		| AT_XDMAC_MBR_UBC_NSEN
1056 		| ublen;
1057 	desc->lld.mbr_cfg = chan_cc;
1058 
1059 	dev_dbg(chan2dev(chan),
1060 		"%s: lld: mbr_sa=%pad, mbr_da=%pad, mbr_ubc=0x%08x, mbr_cfg=0x%08x\n",
1061 		__func__, &desc->lld.mbr_sa, &desc->lld.mbr_da,
1062 		desc->lld.mbr_ubc, desc->lld.mbr_cfg);
1063 
1064 	/* Chain lld. */
1065 	if (prev)
1066 		at_xdmac_queue_desc(chan, prev, desc);
1067 
1068 	return desc;
1069 }
1070 
1071 static struct dma_async_tx_descriptor *
1072 at_xdmac_prep_interleaved(struct dma_chan *chan,
1073 			  struct dma_interleaved_template *xt,
1074 			  unsigned long flags)
1075 {
1076 	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
1077 	struct at_xdmac_desc	*prev = NULL, *first = NULL;
1078 	dma_addr_t		dst_addr, src_addr;
1079 	size_t			src_skip = 0, dst_skip = 0, len = 0;
1080 	struct data_chunk	*chunk;
1081 	int			i;
1082 
1083 	if (!xt || !xt->numf || (xt->dir != DMA_MEM_TO_MEM))
1084 		return NULL;
1085 
1086 	/*
1087 	 * TODO: Handle the case where we have to repeat a chain of
1088 	 * descriptors...
1089 	 */
1090 	if ((xt->numf > 1) && (xt->frame_size > 1))
1091 		return NULL;
1092 
1093 	dev_dbg(chan2dev(chan), "%s: src=%pad, dest=%pad, numf=%zu, frame_size=%zu, flags=0x%lx\n",
1094 		__func__, &xt->src_start, &xt->dst_start,	xt->numf,
1095 		xt->frame_size, flags);
1096 
1097 	src_addr = xt->src_start;
1098 	dst_addr = xt->dst_start;
1099 
1100 	if (xt->numf > 1) {
1101 		first = at_xdmac_interleaved_queue_desc(chan, atchan,
1102 							NULL,
1103 							src_addr, dst_addr,
1104 							xt, xt->sgl);
1105 		if (!first)
1106 			return NULL;
1107 
1108 		/* Length of the block is (BLEN+1) microblocks. */
1109 		for (i = 0; i < xt->numf - 1; i++)
1110 			at_xdmac_increment_block_count(chan, first);
1111 
1112 		dev_dbg(chan2dev(chan), "%s: add desc 0x%p to descs_list 0x%p\n",
1113 			__func__, first, first);
1114 		list_add_tail(&first->desc_node, &first->descs_list);
1115 	} else {
1116 		for (i = 0; i < xt->frame_size; i++) {
1117 			size_t src_icg = 0, dst_icg = 0;
1118 			struct at_xdmac_desc *desc;
1119 
1120 			chunk = xt->sgl + i;
1121 
1122 			dst_icg = dmaengine_get_dst_icg(xt, chunk);
1123 			src_icg = dmaengine_get_src_icg(xt, chunk);
1124 
1125 			src_skip = chunk->size + src_icg;
1126 			dst_skip = chunk->size + dst_icg;
1127 
1128 			dev_dbg(chan2dev(chan),
1129 				"%s: chunk size=%zu, src icg=%zu, dst icg=%zu\n",
1130 				__func__, chunk->size, src_icg, dst_icg);
1131 
1132 			desc = at_xdmac_interleaved_queue_desc(chan, atchan,
1133 							       prev,
1134 							       src_addr, dst_addr,
1135 							       xt, chunk);
1136 			if (!desc) {
1137 				if (first)
1138 					list_splice_tail_init(&first->descs_list,
1139 							      &atchan->free_descs_list);
1140 				return NULL;
1141 			}
1142 
1143 			if (!first)
1144 				first = desc;
1145 
1146 			dev_dbg(chan2dev(chan), "%s: add desc 0x%p to descs_list 0x%p\n",
1147 				__func__, desc, first);
1148 			list_add_tail(&desc->desc_node, &first->descs_list);
1149 
1150 			if (xt->src_sgl)
1151 				src_addr += src_skip;
1152 
1153 			if (xt->dst_sgl)
1154 				dst_addr += dst_skip;
1155 
1156 			len += chunk->size;
1157 			prev = desc;
1158 		}
1159 	}
1160 
1161 	first->tx_dma_desc.cookie = -EBUSY;
1162 	first->tx_dma_desc.flags = flags;
1163 	first->xfer_size = len;
1164 
1165 	return &first->tx_dma_desc;
1166 }
1167 
1168 static struct dma_async_tx_descriptor *
1169 at_xdmac_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
1170 			 size_t len, unsigned long flags)
1171 {
1172 	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
1173 	struct at_xdmac_desc	*first = NULL, *prev = NULL;
1174 	size_t			remaining_size = len, xfer_size = 0, ublen;
1175 	dma_addr_t		src_addr = src, dst_addr = dest;
1176 	u32			dwidth;
1177 	/*
1178 	 * WARNING: We don't know the direction, it involves we can't
1179 	 * dynamically set the source and dest interface so we have to use the
1180 	 * same one. Only interface 0 allows EBI access. Hopefully we can
1181 	 * access DDR through both ports (at least on SAMA5D4x), so we can use
1182 	 * the same interface for source and dest, that solves the fact we
1183 	 * don't know the direction.
1184 	 * ERRATA: Even if useless for memory transfers, the PERID has to not
1185 	 * match the one of another channel. If not, it could lead to spurious
1186 	 * flag status.
1187 	 * For SAMA7G5x case, the SIF and DIF fields are no longer used.
1188 	 * Thus, no need to have the SIF/DIF interfaces here.
1189 	 * For SAMA5D4x and SAMA5D2x the SIF and DIF are already configured as
1190 	 * zero.
1191 	 */
1192 	u32			chan_cc = AT_XDMAC_CC_PERID(0x7f)
1193 					| AT_XDMAC_CC_DAM_INCREMENTED_AM
1194 					| AT_XDMAC_CC_SAM_INCREMENTED_AM
1195 					| AT_XDMAC_CC_MBSIZE_SIXTEEN
1196 					| AT_XDMAC_CC_TYPE_MEM_TRAN;
1197 	unsigned long		irqflags;
1198 
1199 	dev_dbg(chan2dev(chan), "%s: src=%pad, dest=%pad, len=%zd, flags=0x%lx\n",
1200 		__func__, &src, &dest, len, flags);
1201 
1202 	if (unlikely(!len))
1203 		return NULL;
1204 
1205 	dwidth = at_xdmac_align_width(chan, src_addr | dst_addr);
1206 
1207 	/* Prepare descriptors. */
1208 	while (remaining_size) {
1209 		struct at_xdmac_desc	*desc = NULL;
1210 
1211 		dev_dbg(chan2dev(chan), "%s: remaining_size=%zu\n", __func__, remaining_size);
1212 
1213 		spin_lock_irqsave(&atchan->lock, irqflags);
1214 		desc = at_xdmac_get_desc(atchan);
1215 		spin_unlock_irqrestore(&atchan->lock, irqflags);
1216 		if (!desc) {
1217 			dev_err(chan2dev(chan), "can't get descriptor\n");
1218 			if (first)
1219 				list_splice_tail_init(&first->descs_list,
1220 						      &atchan->free_descs_list);
1221 			return NULL;
1222 		}
1223 
1224 		/* Update src and dest addresses. */
1225 		src_addr += xfer_size;
1226 		dst_addr += xfer_size;
1227 
1228 		if (remaining_size >= AT_XDMAC_MBR_UBC_UBLEN_MAX << dwidth)
1229 			xfer_size = AT_XDMAC_MBR_UBC_UBLEN_MAX << dwidth;
1230 		else
1231 			xfer_size = remaining_size;
1232 
1233 		dev_dbg(chan2dev(chan), "%s: xfer_size=%zu\n", __func__, xfer_size);
1234 
1235 		/* Check remaining length and change data width if needed. */
1236 		dwidth = at_xdmac_align_width(chan,
1237 					      src_addr | dst_addr | xfer_size);
1238 		chan_cc &= ~AT_XDMAC_CC_DWIDTH_MASK;
1239 		chan_cc |= AT_XDMAC_CC_DWIDTH(dwidth);
1240 
1241 		ublen = xfer_size >> dwidth;
1242 		remaining_size -= xfer_size;
1243 
1244 		desc->lld.mbr_sa = src_addr;
1245 		desc->lld.mbr_da = dst_addr;
1246 		desc->lld.mbr_ubc = AT_XDMAC_MBR_UBC_NDV2
1247 			| AT_XDMAC_MBR_UBC_NDEN
1248 			| AT_XDMAC_MBR_UBC_NSEN
1249 			| ublen;
1250 		desc->lld.mbr_cfg = chan_cc;
1251 
1252 		dev_dbg(chan2dev(chan),
1253 			 "%s: lld: mbr_sa=%pad, mbr_da=%pad, mbr_ubc=0x%08x, mbr_cfg=0x%08x\n",
1254 			 __func__, &desc->lld.mbr_sa, &desc->lld.mbr_da, desc->lld.mbr_ubc, desc->lld.mbr_cfg);
1255 
1256 		/* Chain lld. */
1257 		if (prev)
1258 			at_xdmac_queue_desc(chan, prev, desc);
1259 
1260 		prev = desc;
1261 		if (!first)
1262 			first = desc;
1263 
1264 		dev_dbg(chan2dev(chan), "%s: add desc 0x%p to descs_list 0x%p\n",
1265 			 __func__, desc, first);
1266 		list_add_tail(&desc->desc_node, &first->descs_list);
1267 	}
1268 
1269 	first->tx_dma_desc.flags = flags;
1270 	first->xfer_size = len;
1271 
1272 	return &first->tx_dma_desc;
1273 }
1274 
1275 static struct at_xdmac_desc *at_xdmac_memset_create_desc(struct dma_chan *chan,
1276 							 struct at_xdmac_chan *atchan,
1277 							 dma_addr_t dst_addr,
1278 							 size_t len,
1279 							 int value)
1280 {
1281 	struct at_xdmac_desc	*desc;
1282 	unsigned long		flags;
1283 	size_t			ublen;
1284 	u32			dwidth;
1285 	char			pattern;
1286 	/*
1287 	 * WARNING: The channel configuration is set here since there is no
1288 	 * dmaengine_slave_config call in this case. Moreover we don't know the
1289 	 * direction, it involves we can't dynamically set the source and dest
1290 	 * interface so we have to use the same one. Only interface 0 allows EBI
1291 	 * access. Hopefully we can access DDR through both ports (at least on
1292 	 * SAMA5D4x), so we can use the same interface for source and dest,
1293 	 * that solves the fact we don't know the direction.
1294 	 * ERRATA: Even if useless for memory transfers, the PERID has to not
1295 	 * match the one of another channel. If not, it could lead to spurious
1296 	 * flag status.
1297 	 * For SAMA7G5x case, the SIF and DIF fields are no longer used.
1298 	 * Thus, no need to have the SIF/DIF interfaces here.
1299 	 * For SAMA5D4x and SAMA5D2x the SIF and DIF are already configured as
1300 	 * zero.
1301 	 */
1302 	u32			chan_cc = AT_XDMAC_CC_PERID(0x7f)
1303 					| AT_XDMAC_CC_DAM_UBS_AM
1304 					| AT_XDMAC_CC_SAM_INCREMENTED_AM
1305 					| AT_XDMAC_CC_MBSIZE_SIXTEEN
1306 					| AT_XDMAC_CC_MEMSET_HW_MODE
1307 					| AT_XDMAC_CC_TYPE_MEM_TRAN;
1308 
1309 	dwidth = at_xdmac_align_width(chan, dst_addr);
1310 
1311 	if (len >= (AT_XDMAC_MBR_UBC_UBLEN_MAX << dwidth)) {
1312 		dev_err(chan2dev(chan),
1313 			"%s: Transfer too large, aborting...\n",
1314 			__func__);
1315 		return NULL;
1316 	}
1317 
1318 	spin_lock_irqsave(&atchan->lock, flags);
1319 	desc = at_xdmac_get_desc(atchan);
1320 	spin_unlock_irqrestore(&atchan->lock, flags);
1321 	if (!desc) {
1322 		dev_err(chan2dev(chan), "can't get descriptor\n");
1323 		return NULL;
1324 	}
1325 
1326 	chan_cc |= AT_XDMAC_CC_DWIDTH(dwidth);
1327 
1328 	/* Only the first byte of value is to be used according to dmaengine */
1329 	pattern = (char)value;
1330 
1331 	ublen = len >> dwidth;
1332 
1333 	desc->lld.mbr_da = dst_addr;
1334 	desc->lld.mbr_ds = (pattern << 24) |
1335 			   (pattern << 16) |
1336 			   (pattern << 8) |
1337 			   pattern;
1338 	desc->lld.mbr_ubc = AT_XDMAC_MBR_UBC_NDV3
1339 		| AT_XDMAC_MBR_UBC_NDEN
1340 		| AT_XDMAC_MBR_UBC_NSEN
1341 		| ublen;
1342 	desc->lld.mbr_cfg = chan_cc;
1343 
1344 	dev_dbg(chan2dev(chan),
1345 		"%s: lld: mbr_da=%pad, mbr_ds=0x%08x, mbr_ubc=0x%08x, mbr_cfg=0x%08x\n",
1346 		__func__, &desc->lld.mbr_da, desc->lld.mbr_ds, desc->lld.mbr_ubc,
1347 		desc->lld.mbr_cfg);
1348 
1349 	return desc;
1350 }
1351 
1352 static struct dma_async_tx_descriptor *
1353 at_xdmac_prep_dma_memset(struct dma_chan *chan, dma_addr_t dest, int value,
1354 			 size_t len, unsigned long flags)
1355 {
1356 	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
1357 	struct at_xdmac_desc	*desc;
1358 
1359 	dev_dbg(chan2dev(chan), "%s: dest=%pad, len=%zu, pattern=0x%x, flags=0x%lx\n",
1360 		__func__, &dest, len, value, flags);
1361 
1362 	if (unlikely(!len))
1363 		return NULL;
1364 
1365 	desc = at_xdmac_memset_create_desc(chan, atchan, dest, len, value);
1366 	list_add_tail(&desc->desc_node, &desc->descs_list);
1367 
1368 	desc->tx_dma_desc.cookie = -EBUSY;
1369 	desc->tx_dma_desc.flags = flags;
1370 	desc->xfer_size = len;
1371 
1372 	return &desc->tx_dma_desc;
1373 }
1374 
1375 static struct dma_async_tx_descriptor *
1376 at_xdmac_prep_dma_memset_sg(struct dma_chan *chan, struct scatterlist *sgl,
1377 			    unsigned int sg_len, int value,
1378 			    unsigned long flags)
1379 {
1380 	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
1381 	struct at_xdmac_desc	*desc, *pdesc = NULL,
1382 				*ppdesc = NULL, *first = NULL;
1383 	struct scatterlist	*sg, *psg = NULL, *ppsg = NULL;
1384 	size_t			stride = 0, pstride = 0, len = 0;
1385 	int			i;
1386 
1387 	if (!sgl)
1388 		return NULL;
1389 
1390 	dev_dbg(chan2dev(chan), "%s: sg_len=%d, value=0x%x, flags=0x%lx\n",
1391 		__func__, sg_len, value, flags);
1392 
1393 	/* Prepare descriptors. */
1394 	for_each_sg(sgl, sg, sg_len, i) {
1395 		dev_dbg(chan2dev(chan), "%s: dest=%pad, len=%d, pattern=0x%x, flags=0x%lx\n",
1396 			__func__, &sg_dma_address(sg), sg_dma_len(sg),
1397 			value, flags);
1398 		desc = at_xdmac_memset_create_desc(chan, atchan,
1399 						   sg_dma_address(sg),
1400 						   sg_dma_len(sg),
1401 						   value);
1402 		if (!desc && first)
1403 			list_splice_tail_init(&first->descs_list,
1404 					      &atchan->free_descs_list);
1405 
1406 		if (!first)
1407 			first = desc;
1408 
1409 		/* Update our strides */
1410 		pstride = stride;
1411 		if (psg)
1412 			stride = sg_dma_address(sg) -
1413 				(sg_dma_address(psg) + sg_dma_len(psg));
1414 
1415 		/*
1416 		 * The scatterlist API gives us only the address and
1417 		 * length of each elements.
1418 		 *
1419 		 * Unfortunately, we don't have the stride, which we
1420 		 * will need to compute.
1421 		 *
1422 		 * That make us end up in a situation like this one:
1423 		 *    len    stride    len    stride    len
1424 		 * +-------+        +-------+        +-------+
1425 		 * |  N-2  |        |  N-1  |        |   N   |
1426 		 * +-------+        +-------+        +-------+
1427 		 *
1428 		 * We need all these three elements (N-2, N-1 and N)
1429 		 * to actually take the decision on whether we need to
1430 		 * queue N-1 or reuse N-2.
1431 		 *
1432 		 * We will only consider N if it is the last element.
1433 		 */
1434 		if (ppdesc && pdesc) {
1435 			if ((stride == pstride) &&
1436 			    (sg_dma_len(ppsg) == sg_dma_len(psg))) {
1437 				dev_dbg(chan2dev(chan),
1438 					"%s: desc 0x%p can be merged with desc 0x%p\n",
1439 					__func__, pdesc, ppdesc);
1440 
1441 				/*
1442 				 * Increment the block count of the
1443 				 * N-2 descriptor
1444 				 */
1445 				at_xdmac_increment_block_count(chan, ppdesc);
1446 				ppdesc->lld.mbr_dus = stride;
1447 
1448 				/*
1449 				 * Put back the N-1 descriptor in the
1450 				 * free descriptor list
1451 				 */
1452 				list_add_tail(&pdesc->desc_node,
1453 					      &atchan->free_descs_list);
1454 
1455 				/*
1456 				 * Make our N-1 descriptor pointer
1457 				 * point to the N-2 since they were
1458 				 * actually merged.
1459 				 */
1460 				pdesc = ppdesc;
1461 
1462 			/*
1463 			 * Rule out the case where we don't have
1464 			 * pstride computed yet (our second sg
1465 			 * element)
1466 			 *
1467 			 * We also want to catch the case where there
1468 			 * would be a negative stride,
1469 			 */
1470 			} else if (pstride ||
1471 				   sg_dma_address(sg) < sg_dma_address(psg)) {
1472 				/*
1473 				 * Queue the N-1 descriptor after the
1474 				 * N-2
1475 				 */
1476 				at_xdmac_queue_desc(chan, ppdesc, pdesc);
1477 
1478 				/*
1479 				 * Add the N-1 descriptor to the list
1480 				 * of the descriptors used for this
1481 				 * transfer
1482 				 */
1483 				list_add_tail(&desc->desc_node,
1484 					      &first->descs_list);
1485 				dev_dbg(chan2dev(chan),
1486 					"%s: add desc 0x%p to descs_list 0x%p\n",
1487 					__func__, desc, first);
1488 			}
1489 		}
1490 
1491 		/*
1492 		 * If we are the last element, just see if we have the
1493 		 * same size than the previous element.
1494 		 *
1495 		 * If so, we can merge it with the previous descriptor
1496 		 * since we don't care about the stride anymore.
1497 		 */
1498 		if ((i == (sg_len - 1)) &&
1499 		    sg_dma_len(psg) == sg_dma_len(sg)) {
1500 			dev_dbg(chan2dev(chan),
1501 				"%s: desc 0x%p can be merged with desc 0x%p\n",
1502 				__func__, desc, pdesc);
1503 
1504 			/*
1505 			 * Increment the block count of the N-1
1506 			 * descriptor
1507 			 */
1508 			at_xdmac_increment_block_count(chan, pdesc);
1509 			pdesc->lld.mbr_dus = stride;
1510 
1511 			/*
1512 			 * Put back the N descriptor in the free
1513 			 * descriptor list
1514 			 */
1515 			list_add_tail(&desc->desc_node,
1516 				      &atchan->free_descs_list);
1517 		}
1518 
1519 		/* Update our descriptors */
1520 		ppdesc = pdesc;
1521 		pdesc = desc;
1522 
1523 		/* Update our scatter pointers */
1524 		ppsg = psg;
1525 		psg = sg;
1526 
1527 		len += sg_dma_len(sg);
1528 	}
1529 
1530 	first->tx_dma_desc.cookie = -EBUSY;
1531 	first->tx_dma_desc.flags = flags;
1532 	first->xfer_size = len;
1533 
1534 	return &first->tx_dma_desc;
1535 }
1536 
1537 static enum dma_status
1538 at_xdmac_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
1539 		   struct dma_tx_state *txstate)
1540 {
1541 	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
1542 	struct at_xdmac		*atxdmac = to_at_xdmac(atchan->chan.device);
1543 	struct at_xdmac_desc	*desc, *_desc, *iter;
1544 	struct list_head	*descs_list;
1545 	enum dma_status		ret;
1546 	int			residue, retry, pm_status;
1547 	u32			cur_nda, check_nda, cur_ubc, mask, value;
1548 	u8			dwidth = 0;
1549 	unsigned long		flags;
1550 	bool			initd;
1551 
1552 	ret = dma_cookie_status(chan, cookie, txstate);
1553 	if (ret == DMA_COMPLETE || !txstate)
1554 		return ret;
1555 
1556 	pm_status = pm_runtime_resume_and_get(atxdmac->dev);
1557 	if (pm_status < 0)
1558 		return DMA_ERROR;
1559 
1560 	spin_lock_irqsave(&atchan->lock, flags);
1561 
1562 	desc = list_first_entry(&atchan->xfers_list, struct at_xdmac_desc, xfer_node);
1563 
1564 	/*
1565 	 * If the transfer has not been started yet, don't need to compute the
1566 	 * residue, it's the transfer length.
1567 	 */
1568 	if (!desc->active_xfer) {
1569 		dma_set_residue(txstate, desc->xfer_size);
1570 		goto spin_unlock;
1571 	}
1572 
1573 	residue = desc->xfer_size;
1574 	/*
1575 	 * Flush FIFO: only relevant when the transfer is source peripheral
1576 	 * synchronized. Flush is needed before reading CUBC because data in
1577 	 * the FIFO are not reported by CUBC. Reporting a residue of the
1578 	 * transfer length while we have data in FIFO can cause issue.
1579 	 * Usecase: atmel USART has a timeout which means I have received
1580 	 * characters but there is no more character received for a while. On
1581 	 * timeout, it requests the residue. If the data are in the DMA FIFO,
1582 	 * we will return a residue of the transfer length. It means no data
1583 	 * received. If an application is waiting for these data, it will hang
1584 	 * since we won't have another USART timeout without receiving new
1585 	 * data.
1586 	 */
1587 	mask = AT_XDMAC_CC_TYPE | AT_XDMAC_CC_DSYNC;
1588 	value = AT_XDMAC_CC_TYPE_PER_TRAN | AT_XDMAC_CC_DSYNC_PER2MEM;
1589 	if ((desc->lld.mbr_cfg & mask) == value) {
1590 		at_xdmac_write(atxdmac, atxdmac->layout->gswf, atchan->mask);
1591 		while (!(at_xdmac_chan_read(atchan, AT_XDMAC_CIS) & AT_XDMAC_CIS_FIS))
1592 			cpu_relax();
1593 	}
1594 
1595 	/*
1596 	 * The easiest way to compute the residue should be to pause the DMA
1597 	 * but doing this can lead to miss some data as some devices don't
1598 	 * have FIFO.
1599 	 * We need to read several registers because:
1600 	 * - DMA is running therefore a descriptor change is possible while
1601 	 * reading these registers
1602 	 * - When the block transfer is done, the value of the CUBC register
1603 	 * is set to its initial value until the fetch of the next descriptor.
1604 	 * This value will corrupt the residue calculation so we have to skip
1605 	 * it.
1606 	 *
1607 	 * INITD --------                    ------------
1608 	 *              |____________________|
1609 	 *       _______________________  _______________
1610 	 * NDA       @desc2             \/   @desc3
1611 	 *       _______________________/\_______________
1612 	 *       __________  ___________  _______________
1613 	 * CUBC       0    \/ MAX desc1 \/  MAX desc2
1614 	 *       __________/\___________/\_______________
1615 	 *
1616 	 * Since descriptors are aligned on 64 bits, we can assume that
1617 	 * the update of NDA and CUBC is atomic.
1618 	 * Memory barriers are used to ensure the read order of the registers.
1619 	 * A max number of retries is set because unlikely it could never ends.
1620 	 */
1621 	for (retry = 0; retry < AT_XDMAC_RESIDUE_MAX_RETRIES; retry++) {
1622 		check_nda = at_xdmac_chan_read(atchan, AT_XDMAC_CNDA) & 0xfffffffc;
1623 		rmb();
1624 		cur_ubc = at_xdmac_chan_read(atchan, AT_XDMAC_CUBC);
1625 		rmb();
1626 		initd = !!(at_xdmac_chan_read(atchan, AT_XDMAC_CC) & AT_XDMAC_CC_INITD);
1627 		rmb();
1628 		cur_nda = at_xdmac_chan_read(atchan, AT_XDMAC_CNDA) & 0xfffffffc;
1629 		rmb();
1630 
1631 		if ((check_nda == cur_nda) && initd)
1632 			break;
1633 	}
1634 
1635 	if (unlikely(retry >= AT_XDMAC_RESIDUE_MAX_RETRIES)) {
1636 		ret = DMA_ERROR;
1637 		goto spin_unlock;
1638 	}
1639 
1640 	/*
1641 	 * Flush FIFO: only relevant when the transfer is source peripheral
1642 	 * synchronized. Another flush is needed here because CUBC is updated
1643 	 * when the controller sends the data write command. It can lead to
1644 	 * report data that are not written in the memory or the device. The
1645 	 * FIFO flush ensures that data are really written.
1646 	 */
1647 	if ((desc->lld.mbr_cfg & mask) == value) {
1648 		at_xdmac_write(atxdmac, atxdmac->layout->gswf, atchan->mask);
1649 		while (!(at_xdmac_chan_read(atchan, AT_XDMAC_CIS) & AT_XDMAC_CIS_FIS))
1650 			cpu_relax();
1651 	}
1652 
1653 	/*
1654 	 * Remove size of all microblocks already transferred and the current
1655 	 * one. Then add the remaining size to transfer of the current
1656 	 * microblock.
1657 	 */
1658 	descs_list = &desc->descs_list;
1659 	list_for_each_entry_safe(iter, _desc, descs_list, desc_node) {
1660 		dwidth = at_xdmac_get_dwidth(iter->lld.mbr_cfg);
1661 		residue -= (iter->lld.mbr_ubc & 0xffffff) << dwidth;
1662 		if ((iter->lld.mbr_nda & 0xfffffffc) == cur_nda) {
1663 			desc = iter;
1664 			break;
1665 		}
1666 	}
1667 	residue += cur_ubc << dwidth;
1668 
1669 	dma_set_residue(txstate, residue);
1670 
1671 	dev_dbg(chan2dev(chan),
1672 		 "%s: desc=0x%p, tx_dma_desc.phys=%pad, tx_status=%d, cookie=%d, residue=%d\n",
1673 		 __func__, desc, &desc->tx_dma_desc.phys, ret, cookie, residue);
1674 
1675 spin_unlock:
1676 	spin_unlock_irqrestore(&atchan->lock, flags);
1677 	pm_runtime_mark_last_busy(atxdmac->dev);
1678 	pm_runtime_put_autosuspend(atxdmac->dev);
1679 	return ret;
1680 }
1681 
1682 static void at_xdmac_advance_work(struct at_xdmac_chan *atchan)
1683 {
1684 	struct at_xdmac_desc	*desc;
1685 
1686 	/*
1687 	 * If channel is enabled, do nothing, advance_work will be triggered
1688 	 * after the interruption.
1689 	 */
1690 	if (at_xdmac_chan_is_enabled(atchan) || list_empty(&atchan->xfers_list))
1691 		return;
1692 
1693 	desc = list_first_entry(&atchan->xfers_list, struct at_xdmac_desc,
1694 				xfer_node);
1695 	dev_vdbg(chan2dev(&atchan->chan), "%s: desc 0x%p\n", __func__, desc);
1696 	if (!desc->active_xfer)
1697 		at_xdmac_start_xfer(atchan, desc);
1698 }
1699 
1700 static void at_xdmac_handle_cyclic(struct at_xdmac_chan *atchan)
1701 {
1702 	struct at_xdmac_desc		*desc;
1703 	struct dma_async_tx_descriptor	*txd;
1704 
1705 	spin_lock_irq(&atchan->lock);
1706 	dev_dbg(chan2dev(&atchan->chan), "%s: status=0x%08x\n",
1707 		__func__, atchan->irq_status);
1708 	if (list_empty(&atchan->xfers_list)) {
1709 		spin_unlock_irq(&atchan->lock);
1710 		return;
1711 	}
1712 	desc = list_first_entry(&atchan->xfers_list, struct at_xdmac_desc,
1713 				xfer_node);
1714 	spin_unlock_irq(&atchan->lock);
1715 	txd = &desc->tx_dma_desc;
1716 	if (txd->flags & DMA_PREP_INTERRUPT)
1717 		dmaengine_desc_get_callback_invoke(txd, NULL);
1718 }
1719 
1720 /* Called with atchan->lock held. */
1721 static void at_xdmac_handle_error(struct at_xdmac_chan *atchan)
1722 {
1723 	struct at_xdmac		*atxdmac = to_at_xdmac(atchan->chan.device);
1724 	struct at_xdmac_desc	*bad_desc;
1725 	int			ret;
1726 
1727 	ret = pm_runtime_resume_and_get(atxdmac->dev);
1728 	if (ret < 0)
1729 		return;
1730 
1731 	/*
1732 	 * The descriptor currently at the head of the active list is
1733 	 * broken. Since we don't have any way to report errors, we'll
1734 	 * just have to scream loudly and try to continue with other
1735 	 * descriptors queued (if any).
1736 	 */
1737 	if (atchan->irq_status & AT_XDMAC_CIS_RBEIS)
1738 		dev_err(chan2dev(&atchan->chan), "read bus error!!!");
1739 	if (atchan->irq_status & AT_XDMAC_CIS_WBEIS)
1740 		dev_err(chan2dev(&atchan->chan), "write bus error!!!");
1741 	if (atchan->irq_status & AT_XDMAC_CIS_ROIS)
1742 		dev_err(chan2dev(&atchan->chan), "request overflow error!!!");
1743 
1744 	/* Channel must be disabled first as it's not done automatically */
1745 	at_xdmac_write(atxdmac, AT_XDMAC_GD, atchan->mask);
1746 	while (at_xdmac_read(atxdmac, AT_XDMAC_GS) & atchan->mask)
1747 		cpu_relax();
1748 
1749 	bad_desc = list_first_entry(&atchan->xfers_list,
1750 				    struct at_xdmac_desc,
1751 				    xfer_node);
1752 
1753 	/* Print bad descriptor's details if needed */
1754 	dev_dbg(chan2dev(&atchan->chan),
1755 		"%s: lld: mbr_sa=%pad, mbr_da=%pad, mbr_ubc=0x%08x\n",
1756 		__func__, &bad_desc->lld.mbr_sa, &bad_desc->lld.mbr_da,
1757 		bad_desc->lld.mbr_ubc);
1758 
1759 	pm_runtime_mark_last_busy(atxdmac->dev);
1760 	pm_runtime_put_autosuspend(atxdmac->dev);
1761 
1762 	/* Then continue with usual descriptor management */
1763 }
1764 
1765 static void at_xdmac_tasklet(struct tasklet_struct *t)
1766 {
1767 	struct at_xdmac_chan	*atchan = from_tasklet(atchan, t, tasklet);
1768 	struct at_xdmac		*atxdmac = to_at_xdmac(atchan->chan.device);
1769 	struct at_xdmac_desc	*desc;
1770 	struct dma_async_tx_descriptor *txd;
1771 	u32			error_mask;
1772 
1773 	if (at_xdmac_chan_is_cyclic(atchan))
1774 		return at_xdmac_handle_cyclic(atchan);
1775 
1776 	error_mask = AT_XDMAC_CIS_RBEIS | AT_XDMAC_CIS_WBEIS |
1777 		AT_XDMAC_CIS_ROIS;
1778 
1779 	spin_lock_irq(&atchan->lock);
1780 
1781 	dev_dbg(chan2dev(&atchan->chan), "%s: status=0x%08x\n",
1782 		__func__, atchan->irq_status);
1783 
1784 	if (!(atchan->irq_status & AT_XDMAC_CIS_LIS) &&
1785 	    !(atchan->irq_status & error_mask)) {
1786 		spin_unlock_irq(&atchan->lock);
1787 		return;
1788 	}
1789 
1790 	if (atchan->irq_status & error_mask)
1791 		at_xdmac_handle_error(atchan);
1792 
1793 	desc = list_first_entry(&atchan->xfers_list, struct at_xdmac_desc,
1794 				xfer_node);
1795 	dev_vdbg(chan2dev(&atchan->chan), "%s: desc 0x%p\n", __func__, desc);
1796 	if (!desc->active_xfer) {
1797 		dev_err(chan2dev(&atchan->chan), "Xfer not active: exiting");
1798 		spin_unlock_irq(&atchan->lock);
1799 		return;
1800 	}
1801 
1802 	txd = &desc->tx_dma_desc;
1803 	dma_cookie_complete(txd);
1804 	/* Remove the transfer from the transfer list. */
1805 	list_del(&desc->xfer_node);
1806 	spin_unlock_irq(&atchan->lock);
1807 
1808 	if (txd->flags & DMA_PREP_INTERRUPT)
1809 		dmaengine_desc_get_callback_invoke(txd, NULL);
1810 
1811 	dma_run_dependencies(txd);
1812 
1813 	spin_lock_irq(&atchan->lock);
1814 	/* Move the xfer descriptors into the free descriptors list. */
1815 	list_splice_tail_init(&desc->descs_list, &atchan->free_descs_list);
1816 	at_xdmac_advance_work(atchan);
1817 	spin_unlock_irq(&atchan->lock);
1818 
1819 	/*
1820 	 * Decrement runtime PM ref counter incremented in
1821 	 * at_xdmac_start_xfer().
1822 	 */
1823 	pm_runtime_mark_last_busy(atxdmac->dev);
1824 	pm_runtime_put_autosuspend(atxdmac->dev);
1825 }
1826 
1827 static irqreturn_t at_xdmac_interrupt(int irq, void *dev_id)
1828 {
1829 	struct at_xdmac		*atxdmac = (struct at_xdmac *)dev_id;
1830 	struct at_xdmac_chan	*atchan;
1831 	u32			imr, status, pending;
1832 	u32			chan_imr, chan_status;
1833 	int			i, ret = IRQ_NONE;
1834 
1835 	do {
1836 		imr = at_xdmac_read(atxdmac, AT_XDMAC_GIM);
1837 		status = at_xdmac_read(atxdmac, AT_XDMAC_GIS);
1838 		pending = status & imr;
1839 
1840 		dev_vdbg(atxdmac->dma.dev,
1841 			 "%s: status=0x%08x, imr=0x%08x, pending=0x%08x\n",
1842 			 __func__, status, imr, pending);
1843 
1844 		if (!pending)
1845 			break;
1846 
1847 		/* We have to find which channel has generated the interrupt. */
1848 		for (i = 0; i < atxdmac->dma.chancnt; i++) {
1849 			if (!((1 << i) & pending))
1850 				continue;
1851 
1852 			atchan = &atxdmac->chan[i];
1853 			chan_imr = at_xdmac_chan_read(atchan, AT_XDMAC_CIM);
1854 			chan_status = at_xdmac_chan_read(atchan, AT_XDMAC_CIS);
1855 			atchan->irq_status = chan_status & chan_imr;
1856 			dev_vdbg(atxdmac->dma.dev,
1857 				 "%s: chan%d: imr=0x%x, status=0x%x\n",
1858 				 __func__, i, chan_imr, chan_status);
1859 			dev_vdbg(chan2dev(&atchan->chan),
1860 				 "%s: CC=0x%08x CNDA=0x%08x, CNDC=0x%08x, CSA=0x%08x, CDA=0x%08x, CUBC=0x%08x\n",
1861 				 __func__,
1862 				 at_xdmac_chan_read(atchan, AT_XDMAC_CC),
1863 				 at_xdmac_chan_read(atchan, AT_XDMAC_CNDA),
1864 				 at_xdmac_chan_read(atchan, AT_XDMAC_CNDC),
1865 				 at_xdmac_chan_read(atchan, AT_XDMAC_CSA),
1866 				 at_xdmac_chan_read(atchan, AT_XDMAC_CDA),
1867 				 at_xdmac_chan_read(atchan, AT_XDMAC_CUBC));
1868 
1869 			if (atchan->irq_status & (AT_XDMAC_CIS_RBEIS | AT_XDMAC_CIS_WBEIS))
1870 				at_xdmac_write(atxdmac, AT_XDMAC_GD, atchan->mask);
1871 
1872 			tasklet_schedule(&atchan->tasklet);
1873 			ret = IRQ_HANDLED;
1874 		}
1875 
1876 	} while (pending);
1877 
1878 	return ret;
1879 }
1880 
1881 static void at_xdmac_issue_pending(struct dma_chan *chan)
1882 {
1883 	struct at_xdmac_chan *atchan = to_at_xdmac_chan(chan);
1884 	unsigned long flags;
1885 
1886 	dev_dbg(chan2dev(&atchan->chan), "%s\n", __func__);
1887 
1888 	spin_lock_irqsave(&atchan->lock, flags);
1889 	at_xdmac_advance_work(atchan);
1890 	spin_unlock_irqrestore(&atchan->lock, flags);
1891 
1892 	return;
1893 }
1894 
1895 static int at_xdmac_device_config(struct dma_chan *chan,
1896 				  struct dma_slave_config *config)
1897 {
1898 	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
1899 	int ret;
1900 	unsigned long		flags;
1901 
1902 	dev_dbg(chan2dev(chan), "%s\n", __func__);
1903 
1904 	spin_lock_irqsave(&atchan->lock, flags);
1905 	ret = at_xdmac_set_slave_config(chan, config);
1906 	spin_unlock_irqrestore(&atchan->lock, flags);
1907 
1908 	return ret;
1909 }
1910 
1911 static void at_xdmac_device_pause_set(struct at_xdmac *atxdmac,
1912 				      struct at_xdmac_chan *atchan)
1913 {
1914 	at_xdmac_write(atxdmac, atxdmac->layout->grws, atchan->mask);
1915 	while (at_xdmac_chan_read(atchan, AT_XDMAC_CC) &
1916 	       (AT_XDMAC_CC_WRIP | AT_XDMAC_CC_RDIP))
1917 		cpu_relax();
1918 }
1919 
1920 static void at_xdmac_device_pause_internal(struct at_xdmac_chan *atchan)
1921 {
1922 	struct at_xdmac		*atxdmac = to_at_xdmac(atchan->chan.device);
1923 	unsigned long		flags;
1924 
1925 	spin_lock_irqsave(&atchan->lock, flags);
1926 	set_bit(AT_XDMAC_CHAN_IS_PAUSED_INTERNAL, &atchan->status);
1927 	at_xdmac_device_pause_set(atxdmac, atchan);
1928 	spin_unlock_irqrestore(&atchan->lock, flags);
1929 }
1930 
1931 static int at_xdmac_device_pause(struct dma_chan *chan)
1932 {
1933 	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
1934 	struct at_xdmac		*atxdmac = to_at_xdmac(atchan->chan.device);
1935 	unsigned long		flags;
1936 	int			ret;
1937 
1938 	dev_dbg(chan2dev(chan), "%s\n", __func__);
1939 
1940 	if (test_and_set_bit(AT_XDMAC_CHAN_IS_PAUSED, &atchan->status))
1941 		return 0;
1942 
1943 	ret = pm_runtime_resume_and_get(atxdmac->dev);
1944 	if (ret < 0)
1945 		return ret;
1946 
1947 	spin_lock_irqsave(&atchan->lock, flags);
1948 
1949 	at_xdmac_device_pause_set(atxdmac, atchan);
1950 	/* Decrement runtime PM ref counter for each active descriptor. */
1951 	at_xdmac_runtime_suspend_descriptors(atchan);
1952 
1953 	spin_unlock_irqrestore(&atchan->lock, flags);
1954 
1955 	pm_runtime_mark_last_busy(atxdmac->dev);
1956 	pm_runtime_put_autosuspend(atxdmac->dev);
1957 
1958 	return 0;
1959 }
1960 
1961 static void at_xdmac_device_resume_internal(struct at_xdmac_chan *atchan)
1962 {
1963 	struct at_xdmac		*atxdmac = to_at_xdmac(atchan->chan.device);
1964 	unsigned long		flags;
1965 
1966 	spin_lock_irqsave(&atchan->lock, flags);
1967 	at_xdmac_write(atxdmac, atxdmac->layout->grwr, atchan->mask);
1968 	clear_bit(AT_XDMAC_CHAN_IS_PAUSED_INTERNAL, &atchan->status);
1969 	spin_unlock_irqrestore(&atchan->lock, flags);
1970 }
1971 
1972 static int at_xdmac_device_resume(struct dma_chan *chan)
1973 {
1974 	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
1975 	struct at_xdmac		*atxdmac = to_at_xdmac(atchan->chan.device);
1976 	unsigned long		flags;
1977 	int			ret;
1978 
1979 	dev_dbg(chan2dev(chan), "%s\n", __func__);
1980 
1981 	ret = pm_runtime_resume_and_get(atxdmac->dev);
1982 	if (ret < 0)
1983 		return ret;
1984 
1985 	spin_lock_irqsave(&atchan->lock, flags);
1986 	if (!at_xdmac_chan_is_paused(atchan))
1987 		goto unlock;
1988 
1989 	/* Increment runtime PM ref counter for each active descriptor. */
1990 	ret = at_xdmac_runtime_resume_descriptors(atchan);
1991 	if (ret < 0)
1992 		goto unlock;
1993 
1994 	at_xdmac_write(atxdmac, atxdmac->layout->grwr, atchan->mask);
1995 	clear_bit(AT_XDMAC_CHAN_IS_PAUSED, &atchan->status);
1996 
1997 unlock:
1998 	spin_unlock_irqrestore(&atchan->lock, flags);
1999 	pm_runtime_mark_last_busy(atxdmac->dev);
2000 	pm_runtime_put_autosuspend(atxdmac->dev);
2001 
2002 	return ret;
2003 }
2004 
2005 static int at_xdmac_device_terminate_all(struct dma_chan *chan)
2006 {
2007 	struct at_xdmac_desc	*desc, *_desc;
2008 	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
2009 	struct at_xdmac		*atxdmac = to_at_xdmac(atchan->chan.device);
2010 	unsigned long		flags;
2011 	int			ret;
2012 
2013 	dev_dbg(chan2dev(chan), "%s\n", __func__);
2014 
2015 	ret = pm_runtime_resume_and_get(atxdmac->dev);
2016 	if (ret < 0)
2017 		return ret;
2018 
2019 	spin_lock_irqsave(&atchan->lock, flags);
2020 	at_xdmac_write(atxdmac, AT_XDMAC_GD, atchan->mask);
2021 	while (at_xdmac_read(atxdmac, AT_XDMAC_GS) & atchan->mask)
2022 		cpu_relax();
2023 
2024 	/* Cancel all pending transfers. */
2025 	list_for_each_entry_safe(desc, _desc, &atchan->xfers_list, xfer_node) {
2026 		list_del(&desc->xfer_node);
2027 		list_splice_tail_init(&desc->descs_list,
2028 				      &atchan->free_descs_list);
2029 		/*
2030 		 * We incremented the runtime PM reference count on
2031 		 * at_xdmac_start_xfer() for this descriptor. Now it's time
2032 		 * to release it.
2033 		 */
2034 		if (desc->active_xfer) {
2035 			pm_runtime_put_autosuspend(atxdmac->dev);
2036 			pm_runtime_mark_last_busy(atxdmac->dev);
2037 		}
2038 	}
2039 
2040 	clear_bit(AT_XDMAC_CHAN_IS_PAUSED, &atchan->status);
2041 	clear_bit(AT_XDMAC_CHAN_IS_CYCLIC, &atchan->status);
2042 	spin_unlock_irqrestore(&atchan->lock, flags);
2043 
2044 	pm_runtime_mark_last_busy(atxdmac->dev);
2045 	pm_runtime_put_autosuspend(atxdmac->dev);
2046 
2047 	return 0;
2048 }
2049 
2050 static int at_xdmac_alloc_chan_resources(struct dma_chan *chan)
2051 {
2052 	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
2053 	struct at_xdmac_desc	*desc;
2054 	int			i;
2055 
2056 	if (at_xdmac_chan_is_enabled(atchan)) {
2057 		dev_err(chan2dev(chan),
2058 			"can't allocate channel resources (channel enabled)\n");
2059 		return -EIO;
2060 	}
2061 
2062 	if (!list_empty(&atchan->free_descs_list)) {
2063 		dev_err(chan2dev(chan),
2064 			"can't allocate channel resources (channel not free from a previous use)\n");
2065 		return -EIO;
2066 	}
2067 
2068 	for (i = 0; i < init_nr_desc_per_channel; i++) {
2069 		desc = at_xdmac_alloc_desc(chan, GFP_KERNEL);
2070 		if (!desc) {
2071 			if (i == 0) {
2072 				dev_warn(chan2dev(chan),
2073 					 "can't allocate any descriptors\n");
2074 				return -EIO;
2075 			}
2076 			dev_warn(chan2dev(chan),
2077 				"only %d descriptors have been allocated\n", i);
2078 			break;
2079 		}
2080 		list_add_tail(&desc->desc_node, &atchan->free_descs_list);
2081 	}
2082 
2083 	dma_cookie_init(chan);
2084 
2085 	dev_dbg(chan2dev(chan), "%s: allocated %d descriptors\n", __func__, i);
2086 
2087 	return i;
2088 }
2089 
2090 static void at_xdmac_free_chan_resources(struct dma_chan *chan)
2091 {
2092 	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
2093 	struct at_xdmac		*atxdmac = to_at_xdmac(chan->device);
2094 	struct at_xdmac_desc	*desc, *_desc;
2095 
2096 	list_for_each_entry_safe(desc, _desc, &atchan->free_descs_list, desc_node) {
2097 		dev_dbg(chan2dev(chan), "%s: freeing descriptor %p\n", __func__, desc);
2098 		list_del(&desc->desc_node);
2099 		dma_pool_free(atxdmac->at_xdmac_desc_pool, desc, desc->tx_dma_desc.phys);
2100 	}
2101 
2102 	return;
2103 }
2104 
2105 static void at_xdmac_axi_config(struct platform_device *pdev)
2106 {
2107 	struct at_xdmac	*atxdmac = (struct at_xdmac *)platform_get_drvdata(pdev);
2108 	bool dev_m2m = false;
2109 	u32 dma_requests;
2110 
2111 	if (!atxdmac->layout->axi_config)
2112 		return; /* Not supported */
2113 
2114 	if (!of_property_read_u32(pdev->dev.of_node, "dma-requests",
2115 				  &dma_requests)) {
2116 		dev_info(&pdev->dev, "controller in mem2mem mode.\n");
2117 		dev_m2m = true;
2118 	}
2119 
2120 	if (dev_m2m) {
2121 		at_xdmac_write(atxdmac, AT_XDMAC_GCFG, AT_XDMAC_GCFG_M2M);
2122 		at_xdmac_write(atxdmac, AT_XDMAC_GWAC, AT_XDMAC_GWAC_M2M);
2123 	} else {
2124 		at_xdmac_write(atxdmac, AT_XDMAC_GCFG, AT_XDMAC_GCFG_P2M);
2125 		at_xdmac_write(atxdmac, AT_XDMAC_GWAC, AT_XDMAC_GWAC_P2M);
2126 	}
2127 }
2128 
2129 static int __maybe_unused atmel_xdmac_prepare(struct device *dev)
2130 {
2131 	struct at_xdmac		*atxdmac = dev_get_drvdata(dev);
2132 	struct dma_chan		*chan, *_chan;
2133 
2134 	list_for_each_entry_safe(chan, _chan, &atxdmac->dma.channels, device_node) {
2135 		struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
2136 
2137 		/* Wait for transfer completion, except in cyclic case. */
2138 		if (at_xdmac_chan_is_enabled(atchan) && !at_xdmac_chan_is_cyclic(atchan))
2139 			return -EAGAIN;
2140 	}
2141 	return 0;
2142 }
2143 
2144 static int __maybe_unused atmel_xdmac_suspend(struct device *dev)
2145 {
2146 	struct at_xdmac		*atxdmac = dev_get_drvdata(dev);
2147 	struct dma_chan		*chan, *_chan;
2148 	int			ret;
2149 
2150 	ret = pm_runtime_resume_and_get(atxdmac->dev);
2151 	if (ret < 0)
2152 		return ret;
2153 
2154 	list_for_each_entry_safe(chan, _chan, &atxdmac->dma.channels, device_node) {
2155 		struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
2156 
2157 		atchan->save_cc = at_xdmac_chan_read(atchan, AT_XDMAC_CC);
2158 		if (at_xdmac_chan_is_cyclic(atchan)) {
2159 			if (!at_xdmac_chan_is_paused(atchan)) {
2160 				dev_warn(chan2dev(chan), "%s: channel %d not paused\n",
2161 					 __func__, chan->chan_id);
2162 				at_xdmac_device_pause_internal(atchan);
2163 				at_xdmac_runtime_suspend_descriptors(atchan);
2164 			}
2165 			atchan->save_cim = at_xdmac_chan_read(atchan, AT_XDMAC_CIM);
2166 			atchan->save_cnda = at_xdmac_chan_read(atchan, AT_XDMAC_CNDA);
2167 			atchan->save_cndc = at_xdmac_chan_read(atchan, AT_XDMAC_CNDC);
2168 		}
2169 	}
2170 	atxdmac->save_gim = at_xdmac_read(atxdmac, AT_XDMAC_GIM);
2171 	atxdmac->save_gs = at_xdmac_read(atxdmac, AT_XDMAC_GS);
2172 
2173 	at_xdmac_off(atxdmac, false);
2174 	pm_runtime_mark_last_busy(atxdmac->dev);
2175 	pm_runtime_put_noidle(atxdmac->dev);
2176 	clk_disable_unprepare(atxdmac->clk);
2177 
2178 	return 0;
2179 }
2180 
2181 static int __maybe_unused atmel_xdmac_resume(struct device *dev)
2182 {
2183 	struct at_xdmac		*atxdmac = dev_get_drvdata(dev);
2184 	struct at_xdmac_chan	*atchan;
2185 	struct dma_chan		*chan, *_chan;
2186 	struct platform_device	*pdev = container_of(dev, struct platform_device, dev);
2187 	int			i, ret;
2188 
2189 	ret = clk_prepare_enable(atxdmac->clk);
2190 	if (ret)
2191 		return ret;
2192 
2193 	pm_runtime_get_noresume(atxdmac->dev);
2194 
2195 	at_xdmac_axi_config(pdev);
2196 
2197 	/* Clear pending interrupts. */
2198 	for (i = 0; i < atxdmac->dma.chancnt; i++) {
2199 		atchan = &atxdmac->chan[i];
2200 		while (at_xdmac_chan_read(atchan, AT_XDMAC_CIS))
2201 			cpu_relax();
2202 	}
2203 
2204 	at_xdmac_write(atxdmac, AT_XDMAC_GIE, atxdmac->save_gim);
2205 	list_for_each_entry_safe(chan, _chan, &atxdmac->dma.channels, device_node) {
2206 		atchan = to_at_xdmac_chan(chan);
2207 
2208 		at_xdmac_chan_write(atchan, AT_XDMAC_CC, atchan->save_cc);
2209 		if (at_xdmac_chan_is_cyclic(atchan)) {
2210 			/*
2211 			 * Resume only channels not explicitly paused by
2212 			 * consumers.
2213 			 */
2214 			if (at_xdmac_chan_is_paused_internal(atchan)) {
2215 				ret = at_xdmac_runtime_resume_descriptors(atchan);
2216 				if (ret < 0)
2217 					return ret;
2218 				at_xdmac_device_resume_internal(atchan);
2219 			}
2220 
2221 			/*
2222 			 * We may resume from a deep sleep state where power
2223 			 * to DMA controller is cut-off. Thus, restore the
2224 			 * suspend state of channels set though dmaengine API.
2225 			 */
2226 			else if (at_xdmac_chan_is_paused(atchan))
2227 				at_xdmac_device_pause_set(atxdmac, atchan);
2228 
2229 			at_xdmac_chan_write(atchan, AT_XDMAC_CNDA, atchan->save_cnda);
2230 			at_xdmac_chan_write(atchan, AT_XDMAC_CNDC, atchan->save_cndc);
2231 			at_xdmac_chan_write(atchan, AT_XDMAC_CIE, atchan->save_cim);
2232 			wmb();
2233 			if (atxdmac->save_gs & atchan->mask)
2234 				at_xdmac_write(atxdmac, AT_XDMAC_GE, atchan->mask);
2235 		}
2236 	}
2237 
2238 	pm_runtime_mark_last_busy(atxdmac->dev);
2239 	pm_runtime_put_autosuspend(atxdmac->dev);
2240 
2241 	return 0;
2242 }
2243 
2244 static int __maybe_unused atmel_xdmac_runtime_suspend(struct device *dev)
2245 {
2246 	struct at_xdmac *atxdmac = dev_get_drvdata(dev);
2247 
2248 	clk_disable(atxdmac->clk);
2249 
2250 	return 0;
2251 }
2252 
2253 static int __maybe_unused atmel_xdmac_runtime_resume(struct device *dev)
2254 {
2255 	struct at_xdmac *atxdmac = dev_get_drvdata(dev);
2256 
2257 	return clk_enable(atxdmac->clk);
2258 }
2259 
2260 static int at_xdmac_probe(struct platform_device *pdev)
2261 {
2262 	struct at_xdmac	*atxdmac;
2263 	int		irq, nr_channels, i, ret;
2264 	void __iomem	*base;
2265 	u32		reg;
2266 
2267 	irq = platform_get_irq(pdev, 0);
2268 	if (irq < 0)
2269 		return irq;
2270 
2271 	base = devm_platform_ioremap_resource(pdev, 0);
2272 	if (IS_ERR(base))
2273 		return PTR_ERR(base);
2274 
2275 	/*
2276 	 * Read number of xdmac channels, read helper function can't be used
2277 	 * since atxdmac is not yet allocated and we need to know the number
2278 	 * of channels to do the allocation.
2279 	 */
2280 	reg = readl_relaxed(base + AT_XDMAC_GTYPE);
2281 	nr_channels = AT_XDMAC_NB_CH(reg);
2282 	if (nr_channels > AT_XDMAC_MAX_CHAN) {
2283 		dev_err(&pdev->dev, "invalid number of channels (%u)\n",
2284 			nr_channels);
2285 		return -EINVAL;
2286 	}
2287 
2288 	atxdmac = devm_kzalloc(&pdev->dev,
2289 			       struct_size(atxdmac, chan, nr_channels),
2290 			       GFP_KERNEL);
2291 	if (!atxdmac) {
2292 		dev_err(&pdev->dev, "can't allocate at_xdmac structure\n");
2293 		return -ENOMEM;
2294 	}
2295 
2296 	atxdmac->regs = base;
2297 	atxdmac->irq = irq;
2298 	atxdmac->dev = &pdev->dev;
2299 
2300 	atxdmac->layout = of_device_get_match_data(&pdev->dev);
2301 	if (!atxdmac->layout)
2302 		return -ENODEV;
2303 
2304 	atxdmac->clk = devm_clk_get(&pdev->dev, "dma_clk");
2305 	if (IS_ERR(atxdmac->clk)) {
2306 		dev_err(&pdev->dev, "can't get dma_clk\n");
2307 		return PTR_ERR(atxdmac->clk);
2308 	}
2309 
2310 	/* Do not use dev res to prevent races with tasklet */
2311 	ret = request_irq(atxdmac->irq, at_xdmac_interrupt, 0, "at_xdmac", atxdmac);
2312 	if (ret) {
2313 		dev_err(&pdev->dev, "can't request irq\n");
2314 		return ret;
2315 	}
2316 
2317 	ret = clk_prepare_enable(atxdmac->clk);
2318 	if (ret) {
2319 		dev_err(&pdev->dev, "can't prepare or enable clock\n");
2320 		goto err_free_irq;
2321 	}
2322 
2323 	atxdmac->at_xdmac_desc_pool =
2324 		dmam_pool_create(dev_name(&pdev->dev), &pdev->dev,
2325 				sizeof(struct at_xdmac_desc), 4, 0);
2326 	if (!atxdmac->at_xdmac_desc_pool) {
2327 		dev_err(&pdev->dev, "no memory for descriptors dma pool\n");
2328 		ret = -ENOMEM;
2329 		goto err_clk_disable;
2330 	}
2331 
2332 	dma_cap_set(DMA_CYCLIC, atxdmac->dma.cap_mask);
2333 	dma_cap_set(DMA_INTERLEAVE, atxdmac->dma.cap_mask);
2334 	dma_cap_set(DMA_MEMCPY, atxdmac->dma.cap_mask);
2335 	dma_cap_set(DMA_MEMSET, atxdmac->dma.cap_mask);
2336 	dma_cap_set(DMA_MEMSET_SG, atxdmac->dma.cap_mask);
2337 	dma_cap_set(DMA_SLAVE, atxdmac->dma.cap_mask);
2338 	/*
2339 	 * Without DMA_PRIVATE the driver is not able to allocate more than
2340 	 * one channel, second allocation fails in private_candidate.
2341 	 */
2342 	dma_cap_set(DMA_PRIVATE, atxdmac->dma.cap_mask);
2343 	atxdmac->dma.dev				= &pdev->dev;
2344 	atxdmac->dma.device_alloc_chan_resources	= at_xdmac_alloc_chan_resources;
2345 	atxdmac->dma.device_free_chan_resources		= at_xdmac_free_chan_resources;
2346 	atxdmac->dma.device_tx_status			= at_xdmac_tx_status;
2347 	atxdmac->dma.device_issue_pending		= at_xdmac_issue_pending;
2348 	atxdmac->dma.device_prep_dma_cyclic		= at_xdmac_prep_dma_cyclic;
2349 	atxdmac->dma.device_prep_interleaved_dma	= at_xdmac_prep_interleaved;
2350 	atxdmac->dma.device_prep_dma_memcpy		= at_xdmac_prep_dma_memcpy;
2351 	atxdmac->dma.device_prep_dma_memset		= at_xdmac_prep_dma_memset;
2352 	atxdmac->dma.device_prep_dma_memset_sg		= at_xdmac_prep_dma_memset_sg;
2353 	atxdmac->dma.device_prep_slave_sg		= at_xdmac_prep_slave_sg;
2354 	atxdmac->dma.device_config			= at_xdmac_device_config;
2355 	atxdmac->dma.device_pause			= at_xdmac_device_pause;
2356 	atxdmac->dma.device_resume			= at_xdmac_device_resume;
2357 	atxdmac->dma.device_terminate_all		= at_xdmac_device_terminate_all;
2358 	atxdmac->dma.src_addr_widths = AT_XDMAC_DMA_BUSWIDTHS;
2359 	atxdmac->dma.dst_addr_widths = AT_XDMAC_DMA_BUSWIDTHS;
2360 	atxdmac->dma.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
2361 	atxdmac->dma.residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
2362 
2363 	platform_set_drvdata(pdev, atxdmac);
2364 
2365 	pm_runtime_set_autosuspend_delay(&pdev->dev, 500);
2366 	pm_runtime_use_autosuspend(&pdev->dev);
2367 	pm_runtime_set_active(&pdev->dev);
2368 	pm_runtime_enable(&pdev->dev);
2369 	pm_runtime_get_noresume(&pdev->dev);
2370 
2371 	/* Init channels. */
2372 	INIT_LIST_HEAD(&atxdmac->dma.channels);
2373 
2374 	/* Disable all chans and interrupts. */
2375 	at_xdmac_off(atxdmac, true);
2376 
2377 	for (i = 0; i < nr_channels; i++) {
2378 		struct at_xdmac_chan *atchan = &atxdmac->chan[i];
2379 
2380 		atchan->chan.device = &atxdmac->dma;
2381 		list_add_tail(&atchan->chan.device_node,
2382 			      &atxdmac->dma.channels);
2383 
2384 		atchan->ch_regs = at_xdmac_chan_reg_base(atxdmac, i);
2385 		atchan->mask = 1 << i;
2386 
2387 		spin_lock_init(&atchan->lock);
2388 		INIT_LIST_HEAD(&atchan->xfers_list);
2389 		INIT_LIST_HEAD(&atchan->free_descs_list);
2390 		tasklet_setup(&atchan->tasklet, at_xdmac_tasklet);
2391 
2392 		/* Clear pending interrupts. */
2393 		while (at_xdmac_chan_read(atchan, AT_XDMAC_CIS))
2394 			cpu_relax();
2395 	}
2396 
2397 	ret = dma_async_device_register(&atxdmac->dma);
2398 	if (ret) {
2399 		dev_err(&pdev->dev, "fail to register DMA engine device\n");
2400 		goto err_pm_disable;
2401 	}
2402 
2403 	ret = of_dma_controller_register(pdev->dev.of_node,
2404 					 at_xdmac_xlate, atxdmac);
2405 	if (ret) {
2406 		dev_err(&pdev->dev, "could not register of dma controller\n");
2407 		goto err_dma_unregister;
2408 	}
2409 
2410 	dev_info(&pdev->dev, "%d channels, mapped at 0x%p\n",
2411 		 nr_channels, atxdmac->regs);
2412 
2413 	at_xdmac_axi_config(pdev);
2414 
2415 	pm_runtime_mark_last_busy(&pdev->dev);
2416 	pm_runtime_put_autosuspend(&pdev->dev);
2417 
2418 	return 0;
2419 
2420 err_dma_unregister:
2421 	dma_async_device_unregister(&atxdmac->dma);
2422 err_pm_disable:
2423 	pm_runtime_put_noidle(&pdev->dev);
2424 	pm_runtime_disable(&pdev->dev);
2425 	pm_runtime_set_suspended(&pdev->dev);
2426 	pm_runtime_dont_use_autosuspend(&pdev->dev);
2427 err_clk_disable:
2428 	clk_disable_unprepare(atxdmac->clk);
2429 err_free_irq:
2430 	free_irq(atxdmac->irq, atxdmac);
2431 	return ret;
2432 }
2433 
2434 static int at_xdmac_remove(struct platform_device *pdev)
2435 {
2436 	struct at_xdmac	*atxdmac = (struct at_xdmac *)platform_get_drvdata(pdev);
2437 	int		i;
2438 
2439 	at_xdmac_off(atxdmac, true);
2440 	of_dma_controller_free(pdev->dev.of_node);
2441 	dma_async_device_unregister(&atxdmac->dma);
2442 	pm_runtime_disable(atxdmac->dev);
2443 	pm_runtime_set_suspended(&pdev->dev);
2444 	pm_runtime_dont_use_autosuspend(&pdev->dev);
2445 	clk_disable_unprepare(atxdmac->clk);
2446 
2447 	free_irq(atxdmac->irq, atxdmac);
2448 
2449 	for (i = 0; i < atxdmac->dma.chancnt; i++) {
2450 		struct at_xdmac_chan *atchan = &atxdmac->chan[i];
2451 
2452 		tasklet_kill(&atchan->tasklet);
2453 		at_xdmac_free_chan_resources(&atchan->chan);
2454 	}
2455 
2456 	return 0;
2457 }
2458 
2459 static const struct dev_pm_ops __maybe_unused atmel_xdmac_dev_pm_ops = {
2460 	.prepare	= atmel_xdmac_prepare,
2461 	SET_LATE_SYSTEM_SLEEP_PM_OPS(atmel_xdmac_suspend, atmel_xdmac_resume)
2462 	SET_RUNTIME_PM_OPS(atmel_xdmac_runtime_suspend,
2463 			   atmel_xdmac_runtime_resume, NULL)
2464 };
2465 
2466 static const struct of_device_id atmel_xdmac_dt_ids[] = {
2467 	{
2468 		.compatible = "atmel,sama5d4-dma",
2469 		.data = &at_xdmac_sama5d4_layout,
2470 	}, {
2471 		.compatible = "microchip,sama7g5-dma",
2472 		.data = &at_xdmac_sama7g5_layout,
2473 	}, {
2474 		/* sentinel */
2475 	}
2476 };
2477 MODULE_DEVICE_TABLE(of, atmel_xdmac_dt_ids);
2478 
2479 static struct platform_driver at_xdmac_driver = {
2480 	.probe		= at_xdmac_probe,
2481 	.remove		= at_xdmac_remove,
2482 	.driver = {
2483 		.name		= "at_xdmac",
2484 		.of_match_table	= of_match_ptr(atmel_xdmac_dt_ids),
2485 		.pm		= pm_ptr(&atmel_xdmac_dev_pm_ops),
2486 	}
2487 };
2488 
2489 static int __init at_xdmac_init(void)
2490 {
2491 	return platform_driver_register(&at_xdmac_driver);
2492 }
2493 subsys_initcall(at_xdmac_init);
2494 
2495 static void __exit at_xdmac_exit(void)
2496 {
2497 	platform_driver_unregister(&at_xdmac_driver);
2498 }
2499 module_exit(at_xdmac_exit);
2500 
2501 MODULE_DESCRIPTION("Atmel Extended DMA Controller driver");
2502 MODULE_AUTHOR("Ludovic Desroches <ludovic.desroches@atmel.com>");
2503 MODULE_LICENSE("GPL");
2504