xref: /linux/drivers/dma/dma-jz4780.c (revision ea8a163e02d6925773129e2dd86e419e491b791d)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Ingenic JZ4780 DMA controller
4  *
5  * Copyright (c) 2015 Imagination Technologies
6  * Author: Alex Smith <alex@alex-smith.me.uk>
7  */
8 
9 #include <linux/clk.h>
10 #include <linux/dmapool.h>
11 #include <linux/init.h>
12 #include <linux/interrupt.h>
13 #include <linux/module.h>
14 #include <linux/of.h>
15 #include <linux/of_device.h>
16 #include <linux/of_dma.h>
17 #include <linux/platform_device.h>
18 #include <linux/slab.h>
19 
20 #include "dmaengine.h"
21 #include "virt-dma.h"
22 
23 /* Global registers. */
24 #define JZ_DMA_REG_DMAC		0x00
25 #define JZ_DMA_REG_DIRQP	0x04
26 #define JZ_DMA_REG_DDR		0x08
27 #define JZ_DMA_REG_DDRS		0x0c
28 #define JZ_DMA_REG_DCKE		0x10
29 #define JZ_DMA_REG_DCKES	0x14
30 #define JZ_DMA_REG_DCKEC	0x18
31 #define JZ_DMA_REG_DMACP	0x1c
32 #define JZ_DMA_REG_DSIRQP	0x20
33 #define JZ_DMA_REG_DSIRQM	0x24
34 #define JZ_DMA_REG_DCIRQP	0x28
35 #define JZ_DMA_REG_DCIRQM	0x2c
36 
37 /* Per-channel registers. */
38 #define JZ_DMA_REG_CHAN(n)	(n * 0x20)
39 #define JZ_DMA_REG_DSA		0x00
40 #define JZ_DMA_REG_DTA		0x04
41 #define JZ_DMA_REG_DTC		0x08
42 #define JZ_DMA_REG_DRT		0x0c
43 #define JZ_DMA_REG_DCS		0x10
44 #define JZ_DMA_REG_DCM		0x14
45 #define JZ_DMA_REG_DDA		0x18
46 #define JZ_DMA_REG_DSD		0x1c
47 
48 #define JZ_DMA_DMAC_DMAE	BIT(0)
49 #define JZ_DMA_DMAC_AR		BIT(2)
50 #define JZ_DMA_DMAC_HLT		BIT(3)
51 #define JZ_DMA_DMAC_FAIC	BIT(27)
52 #define JZ_DMA_DMAC_FMSC	BIT(31)
53 
54 #define JZ_DMA_DRT_AUTO		0x8
55 
56 #define JZ_DMA_DCS_CTE		BIT(0)
57 #define JZ_DMA_DCS_HLT		BIT(2)
58 #define JZ_DMA_DCS_TT		BIT(3)
59 #define JZ_DMA_DCS_AR		BIT(4)
60 #define JZ_DMA_DCS_DES8		BIT(30)
61 
62 #define JZ_DMA_DCM_LINK		BIT(0)
63 #define JZ_DMA_DCM_TIE		BIT(1)
64 #define JZ_DMA_DCM_STDE		BIT(2)
65 #define JZ_DMA_DCM_TSZ_SHIFT	8
66 #define JZ_DMA_DCM_TSZ_MASK	(0x7 << JZ_DMA_DCM_TSZ_SHIFT)
67 #define JZ_DMA_DCM_DP_SHIFT	12
68 #define JZ_DMA_DCM_SP_SHIFT	14
69 #define JZ_DMA_DCM_DAI		BIT(22)
70 #define JZ_DMA_DCM_SAI		BIT(23)
71 
72 #define JZ_DMA_SIZE_4_BYTE	0x0
73 #define JZ_DMA_SIZE_1_BYTE	0x1
74 #define JZ_DMA_SIZE_2_BYTE	0x2
75 #define JZ_DMA_SIZE_16_BYTE	0x3
76 #define JZ_DMA_SIZE_32_BYTE	0x4
77 #define JZ_DMA_SIZE_64_BYTE	0x5
78 #define JZ_DMA_SIZE_128_BYTE	0x6
79 
80 #define JZ_DMA_WIDTH_32_BIT	0x0
81 #define JZ_DMA_WIDTH_8_BIT	0x1
82 #define JZ_DMA_WIDTH_16_BIT	0x2
83 
84 #define JZ_DMA_BUSWIDTHS	(BIT(DMA_SLAVE_BUSWIDTH_1_BYTE)	 | \
85 				 BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) | \
86 				 BIT(DMA_SLAVE_BUSWIDTH_4_BYTES))
87 
88 #define JZ4780_DMA_CTRL_OFFSET	0x1000
89 
90 /* macros for use with jz4780_dma_soc_data.flags */
91 #define JZ_SOC_DATA_ALLOW_LEGACY_DT	BIT(0)
92 #define JZ_SOC_DATA_PROGRAMMABLE_DMA	BIT(1)
93 #define JZ_SOC_DATA_PER_CHAN_PM		BIT(2)
94 #define JZ_SOC_DATA_NO_DCKES_DCKEC	BIT(3)
95 #define JZ_SOC_DATA_BREAK_LINKS		BIT(4)
96 
97 /**
98  * struct jz4780_dma_hwdesc - descriptor structure read by the DMA controller.
99  * @dcm: value for the DCM (channel command) register
100  * @dsa: source address
101  * @dta: target address
102  * @dtc: transfer count (number of blocks of the transfer size specified in DCM
103  * to transfer) in the low 24 bits, offset of the next descriptor from the
104  * descriptor base address in the upper 8 bits.
105  */
106 struct jz4780_dma_hwdesc {
107 	uint32_t dcm;
108 	uint32_t dsa;
109 	uint32_t dta;
110 	uint32_t dtc;
111 };
112 
113 /* Size of allocations for hardware descriptor blocks. */
114 #define JZ_DMA_DESC_BLOCK_SIZE	PAGE_SIZE
115 #define JZ_DMA_MAX_DESC		\
116 	(JZ_DMA_DESC_BLOCK_SIZE / sizeof(struct jz4780_dma_hwdesc))
117 
118 struct jz4780_dma_desc {
119 	struct virt_dma_desc vdesc;
120 
121 	struct jz4780_dma_hwdesc *desc;
122 	dma_addr_t desc_phys;
123 	unsigned int count;
124 	enum dma_transaction_type type;
125 	uint32_t status;
126 };
127 
128 struct jz4780_dma_chan {
129 	struct virt_dma_chan vchan;
130 	unsigned int id;
131 	struct dma_pool *desc_pool;
132 
133 	uint32_t transfer_type;
134 	uint32_t transfer_shift;
135 	struct dma_slave_config	config;
136 
137 	struct jz4780_dma_desc *desc;
138 	unsigned int curr_hwdesc;
139 };
140 
141 struct jz4780_dma_soc_data {
142 	unsigned int nb_channels;
143 	unsigned int transfer_ord_max;
144 	unsigned long flags;
145 };
146 
147 struct jz4780_dma_dev {
148 	struct dma_device dma_device;
149 	void __iomem *chn_base;
150 	void __iomem *ctrl_base;
151 	struct clk *clk;
152 	unsigned int irq;
153 	const struct jz4780_dma_soc_data *soc_data;
154 
155 	uint32_t chan_reserved;
156 	struct jz4780_dma_chan chan[];
157 };
158 
159 struct jz4780_dma_filter_data {
160 	uint32_t transfer_type;
161 	int channel;
162 };
163 
164 static inline struct jz4780_dma_chan *to_jz4780_dma_chan(struct dma_chan *chan)
165 {
166 	return container_of(chan, struct jz4780_dma_chan, vchan.chan);
167 }
168 
169 static inline struct jz4780_dma_desc *to_jz4780_dma_desc(
170 	struct virt_dma_desc *vdesc)
171 {
172 	return container_of(vdesc, struct jz4780_dma_desc, vdesc);
173 }
174 
175 static inline struct jz4780_dma_dev *jz4780_dma_chan_parent(
176 	struct jz4780_dma_chan *jzchan)
177 {
178 	return container_of(jzchan->vchan.chan.device, struct jz4780_dma_dev,
179 			    dma_device);
180 }
181 
182 static inline uint32_t jz4780_dma_chn_readl(struct jz4780_dma_dev *jzdma,
183 	unsigned int chn, unsigned int reg)
184 {
185 	return readl(jzdma->chn_base + reg + JZ_DMA_REG_CHAN(chn));
186 }
187 
188 static inline void jz4780_dma_chn_writel(struct jz4780_dma_dev *jzdma,
189 	unsigned int chn, unsigned int reg, uint32_t val)
190 {
191 	writel(val, jzdma->chn_base + reg + JZ_DMA_REG_CHAN(chn));
192 }
193 
194 static inline uint32_t jz4780_dma_ctrl_readl(struct jz4780_dma_dev *jzdma,
195 	unsigned int reg)
196 {
197 	return readl(jzdma->ctrl_base + reg);
198 }
199 
200 static inline void jz4780_dma_ctrl_writel(struct jz4780_dma_dev *jzdma,
201 	unsigned int reg, uint32_t val)
202 {
203 	writel(val, jzdma->ctrl_base + reg);
204 }
205 
206 static inline void jz4780_dma_chan_enable(struct jz4780_dma_dev *jzdma,
207 	unsigned int chn)
208 {
209 	if (jzdma->soc_data->flags & JZ_SOC_DATA_PER_CHAN_PM) {
210 		unsigned int reg;
211 
212 		if (jzdma->soc_data->flags & JZ_SOC_DATA_NO_DCKES_DCKEC)
213 			reg = JZ_DMA_REG_DCKE;
214 		else
215 			reg = JZ_DMA_REG_DCKES;
216 
217 		jz4780_dma_ctrl_writel(jzdma, reg, BIT(chn));
218 	}
219 }
220 
221 static inline void jz4780_dma_chan_disable(struct jz4780_dma_dev *jzdma,
222 	unsigned int chn)
223 {
224 	if ((jzdma->soc_data->flags & JZ_SOC_DATA_PER_CHAN_PM) &&
225 			!(jzdma->soc_data->flags & JZ_SOC_DATA_NO_DCKES_DCKEC))
226 		jz4780_dma_ctrl_writel(jzdma, JZ_DMA_REG_DCKEC, BIT(chn));
227 }
228 
229 static struct jz4780_dma_desc *jz4780_dma_desc_alloc(
230 	struct jz4780_dma_chan *jzchan, unsigned int count,
231 	enum dma_transaction_type type)
232 {
233 	struct jz4780_dma_desc *desc;
234 
235 	if (count > JZ_DMA_MAX_DESC)
236 		return NULL;
237 
238 	desc = kzalloc(sizeof(*desc), GFP_NOWAIT);
239 	if (!desc)
240 		return NULL;
241 
242 	desc->desc = dma_pool_alloc(jzchan->desc_pool, GFP_NOWAIT,
243 				    &desc->desc_phys);
244 	if (!desc->desc) {
245 		kfree(desc);
246 		return NULL;
247 	}
248 
249 	desc->count = count;
250 	desc->type = type;
251 	return desc;
252 }
253 
254 static void jz4780_dma_desc_free(struct virt_dma_desc *vdesc)
255 {
256 	struct jz4780_dma_desc *desc = to_jz4780_dma_desc(vdesc);
257 	struct jz4780_dma_chan *jzchan = to_jz4780_dma_chan(vdesc->tx.chan);
258 
259 	dma_pool_free(jzchan->desc_pool, desc->desc, desc->desc_phys);
260 	kfree(desc);
261 }
262 
263 static uint32_t jz4780_dma_transfer_size(struct jz4780_dma_chan *jzchan,
264 	unsigned long val, uint32_t *shift)
265 {
266 	struct jz4780_dma_dev *jzdma = jz4780_dma_chan_parent(jzchan);
267 	int ord = ffs(val) - 1;
268 
269 	/*
270 	 * 8 byte transfer sizes unsupported so fall back on 4. If it's larger
271 	 * than the maximum, just limit it. It is perfectly safe to fall back
272 	 * in this way since we won't exceed the maximum burst size supported
273 	 * by the device, the only effect is reduced efficiency. This is better
274 	 * than refusing to perform the request at all.
275 	 */
276 	if (ord == 3)
277 		ord = 2;
278 	else if (ord > jzdma->soc_data->transfer_ord_max)
279 		ord = jzdma->soc_data->transfer_ord_max;
280 
281 	*shift = ord;
282 
283 	switch (ord) {
284 	case 0:
285 		return JZ_DMA_SIZE_1_BYTE;
286 	case 1:
287 		return JZ_DMA_SIZE_2_BYTE;
288 	case 2:
289 		return JZ_DMA_SIZE_4_BYTE;
290 	case 4:
291 		return JZ_DMA_SIZE_16_BYTE;
292 	case 5:
293 		return JZ_DMA_SIZE_32_BYTE;
294 	case 6:
295 		return JZ_DMA_SIZE_64_BYTE;
296 	default:
297 		return JZ_DMA_SIZE_128_BYTE;
298 	}
299 }
300 
301 static int jz4780_dma_setup_hwdesc(struct jz4780_dma_chan *jzchan,
302 	struct jz4780_dma_hwdesc *desc, dma_addr_t addr, size_t len,
303 	enum dma_transfer_direction direction)
304 {
305 	struct dma_slave_config *config = &jzchan->config;
306 	uint32_t width, maxburst, tsz;
307 
308 	if (direction == DMA_MEM_TO_DEV) {
309 		desc->dcm = JZ_DMA_DCM_SAI;
310 		desc->dsa = addr;
311 		desc->dta = config->dst_addr;
312 
313 		width = config->dst_addr_width;
314 		maxburst = config->dst_maxburst;
315 	} else {
316 		desc->dcm = JZ_DMA_DCM_DAI;
317 		desc->dsa = config->src_addr;
318 		desc->dta = addr;
319 
320 		width = config->src_addr_width;
321 		maxburst = config->src_maxburst;
322 	}
323 
324 	/*
325 	 * This calculates the maximum transfer size that can be used with the
326 	 * given address, length, width and maximum burst size. The address
327 	 * must be aligned to the transfer size, the total length must be
328 	 * divisible by the transfer size, and we must not use more than the
329 	 * maximum burst specified by the user.
330 	 */
331 	tsz = jz4780_dma_transfer_size(jzchan, addr | len | (width * maxburst),
332 				       &jzchan->transfer_shift);
333 
334 	switch (width) {
335 	case DMA_SLAVE_BUSWIDTH_1_BYTE:
336 	case DMA_SLAVE_BUSWIDTH_2_BYTES:
337 		break;
338 	case DMA_SLAVE_BUSWIDTH_4_BYTES:
339 		width = JZ_DMA_WIDTH_32_BIT;
340 		break;
341 	default:
342 		return -EINVAL;
343 	}
344 
345 	desc->dcm |= tsz << JZ_DMA_DCM_TSZ_SHIFT;
346 	desc->dcm |= width << JZ_DMA_DCM_SP_SHIFT;
347 	desc->dcm |= width << JZ_DMA_DCM_DP_SHIFT;
348 
349 	desc->dtc = len >> jzchan->transfer_shift;
350 	return 0;
351 }
352 
353 static struct dma_async_tx_descriptor *jz4780_dma_prep_slave_sg(
354 	struct dma_chan *chan, struct scatterlist *sgl, unsigned int sg_len,
355 	enum dma_transfer_direction direction, unsigned long flags,
356 	void *context)
357 {
358 	struct jz4780_dma_chan *jzchan = to_jz4780_dma_chan(chan);
359 	struct jz4780_dma_dev *jzdma = jz4780_dma_chan_parent(jzchan);
360 	struct jz4780_dma_desc *desc;
361 	unsigned int i;
362 	int err;
363 
364 	desc = jz4780_dma_desc_alloc(jzchan, sg_len, DMA_SLAVE);
365 	if (!desc)
366 		return NULL;
367 
368 	for (i = 0; i < sg_len; i++) {
369 		err = jz4780_dma_setup_hwdesc(jzchan, &desc->desc[i],
370 					      sg_dma_address(&sgl[i]),
371 					      sg_dma_len(&sgl[i]),
372 					      direction);
373 		if (err < 0) {
374 			jz4780_dma_desc_free(&jzchan->desc->vdesc);
375 			return NULL;
376 		}
377 
378 		desc->desc[i].dcm |= JZ_DMA_DCM_TIE;
379 
380 		if (i != (sg_len - 1) &&
381 		    !(jzdma->soc_data->flags & JZ_SOC_DATA_BREAK_LINKS)) {
382 			/* Automatically proceeed to the next descriptor. */
383 			desc->desc[i].dcm |= JZ_DMA_DCM_LINK;
384 
385 			/*
386 			 * The upper 8 bits of the DTC field in the descriptor
387 			 * must be set to (offset from descriptor base of next
388 			 * descriptor >> 4).
389 			 */
390 			desc->desc[i].dtc |=
391 				(((i + 1) * sizeof(*desc->desc)) >> 4) << 24;
392 		}
393 	}
394 
395 	return vchan_tx_prep(&jzchan->vchan, &desc->vdesc, flags);
396 }
397 
398 static struct dma_async_tx_descriptor *jz4780_dma_prep_dma_cyclic(
399 	struct dma_chan *chan, dma_addr_t buf_addr, size_t buf_len,
400 	size_t period_len, enum dma_transfer_direction direction,
401 	unsigned long flags)
402 {
403 	struct jz4780_dma_chan *jzchan = to_jz4780_dma_chan(chan);
404 	struct jz4780_dma_desc *desc;
405 	unsigned int periods, i;
406 	int err;
407 
408 	if (buf_len % period_len)
409 		return NULL;
410 
411 	periods = buf_len / period_len;
412 
413 	desc = jz4780_dma_desc_alloc(jzchan, periods, DMA_CYCLIC);
414 	if (!desc)
415 		return NULL;
416 
417 	for (i = 0; i < periods; i++) {
418 		err = jz4780_dma_setup_hwdesc(jzchan, &desc->desc[i], buf_addr,
419 					      period_len, direction);
420 		if (err < 0) {
421 			jz4780_dma_desc_free(&jzchan->desc->vdesc);
422 			return NULL;
423 		}
424 
425 		buf_addr += period_len;
426 
427 		/*
428 		 * Set the link bit to indicate that the controller should
429 		 * automatically proceed to the next descriptor. In
430 		 * jz4780_dma_begin(), this will be cleared if we need to issue
431 		 * an interrupt after each period.
432 		 */
433 		desc->desc[i].dcm |= JZ_DMA_DCM_TIE | JZ_DMA_DCM_LINK;
434 
435 		/*
436 		 * The upper 8 bits of the DTC field in the descriptor must be
437 		 * set to (offset from descriptor base of next descriptor >> 4).
438 		 * If this is the last descriptor, link it back to the first,
439 		 * i.e. leave offset set to 0, otherwise point to the next one.
440 		 */
441 		if (i != (periods - 1)) {
442 			desc->desc[i].dtc |=
443 				(((i + 1) * sizeof(*desc->desc)) >> 4) << 24;
444 		}
445 	}
446 
447 	return vchan_tx_prep(&jzchan->vchan, &desc->vdesc, flags);
448 }
449 
450 static struct dma_async_tx_descriptor *jz4780_dma_prep_dma_memcpy(
451 	struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
452 	size_t len, unsigned long flags)
453 {
454 	struct jz4780_dma_chan *jzchan = to_jz4780_dma_chan(chan);
455 	struct jz4780_dma_desc *desc;
456 	uint32_t tsz;
457 
458 	desc = jz4780_dma_desc_alloc(jzchan, 1, DMA_MEMCPY);
459 	if (!desc)
460 		return NULL;
461 
462 	tsz = jz4780_dma_transfer_size(jzchan, dest | src | len,
463 				       &jzchan->transfer_shift);
464 
465 	jzchan->transfer_type = JZ_DMA_DRT_AUTO;
466 
467 	desc->desc[0].dsa = src;
468 	desc->desc[0].dta = dest;
469 	desc->desc[0].dcm = JZ_DMA_DCM_TIE | JZ_DMA_DCM_SAI | JZ_DMA_DCM_DAI |
470 			    tsz << JZ_DMA_DCM_TSZ_SHIFT |
471 			    JZ_DMA_WIDTH_32_BIT << JZ_DMA_DCM_SP_SHIFT |
472 			    JZ_DMA_WIDTH_32_BIT << JZ_DMA_DCM_DP_SHIFT;
473 	desc->desc[0].dtc = len >> jzchan->transfer_shift;
474 
475 	return vchan_tx_prep(&jzchan->vchan, &desc->vdesc, flags);
476 }
477 
478 static void jz4780_dma_begin(struct jz4780_dma_chan *jzchan)
479 {
480 	struct jz4780_dma_dev *jzdma = jz4780_dma_chan_parent(jzchan);
481 	struct virt_dma_desc *vdesc;
482 	unsigned int i;
483 	dma_addr_t desc_phys;
484 
485 	if (!jzchan->desc) {
486 		vdesc = vchan_next_desc(&jzchan->vchan);
487 		if (!vdesc)
488 			return;
489 
490 		list_del(&vdesc->node);
491 
492 		jzchan->desc = to_jz4780_dma_desc(vdesc);
493 		jzchan->curr_hwdesc = 0;
494 
495 		if (jzchan->desc->type == DMA_CYCLIC && vdesc->tx.callback) {
496 			/*
497 			 * The DMA controller doesn't support triggering an
498 			 * interrupt after processing each descriptor, only
499 			 * after processing an entire terminated list of
500 			 * descriptors. For a cyclic DMA setup the list of
501 			 * descriptors is not terminated so we can never get an
502 			 * interrupt.
503 			 *
504 			 * If the user requested a callback for a cyclic DMA
505 			 * setup then we workaround this hardware limitation
506 			 * here by degrading to a set of unlinked descriptors
507 			 * which we will submit in sequence in response to the
508 			 * completion of processing the previous descriptor.
509 			 */
510 			for (i = 0; i < jzchan->desc->count; i++)
511 				jzchan->desc->desc[i].dcm &= ~JZ_DMA_DCM_LINK;
512 		}
513 	} else {
514 		/*
515 		 * There is an existing transfer, therefore this must be one
516 		 * for which we unlinked the descriptors above. Advance to the
517 		 * next one in the list.
518 		 */
519 		jzchan->curr_hwdesc =
520 			(jzchan->curr_hwdesc + 1) % jzchan->desc->count;
521 	}
522 
523 	/* Enable the channel's clock. */
524 	jz4780_dma_chan_enable(jzdma, jzchan->id);
525 
526 	/* Use 4-word descriptors. */
527 	jz4780_dma_chn_writel(jzdma, jzchan->id, JZ_DMA_REG_DCS, 0);
528 
529 	/* Set transfer type. */
530 	jz4780_dma_chn_writel(jzdma, jzchan->id, JZ_DMA_REG_DRT,
531 			      jzchan->transfer_type);
532 
533 	/*
534 	 * Set the transfer count. This is redundant for a descriptor-driven
535 	 * transfer. However, there can be a delay between the transfer start
536 	 * time and when DTCn reg contains the new transfer count. Setting
537 	 * it explicitly ensures residue is computed correctly at all times.
538 	 */
539 	jz4780_dma_chn_writel(jzdma, jzchan->id, JZ_DMA_REG_DTC,
540 				jzchan->desc->desc[jzchan->curr_hwdesc].dtc);
541 
542 	/* Write descriptor address and initiate descriptor fetch. */
543 	desc_phys = jzchan->desc->desc_phys +
544 		    (jzchan->curr_hwdesc * sizeof(*jzchan->desc->desc));
545 	jz4780_dma_chn_writel(jzdma, jzchan->id, JZ_DMA_REG_DDA, desc_phys);
546 	jz4780_dma_ctrl_writel(jzdma, JZ_DMA_REG_DDRS, BIT(jzchan->id));
547 
548 	/* Enable the channel. */
549 	jz4780_dma_chn_writel(jzdma, jzchan->id, JZ_DMA_REG_DCS,
550 			      JZ_DMA_DCS_CTE);
551 }
552 
553 static void jz4780_dma_issue_pending(struct dma_chan *chan)
554 {
555 	struct jz4780_dma_chan *jzchan = to_jz4780_dma_chan(chan);
556 	unsigned long flags;
557 
558 	spin_lock_irqsave(&jzchan->vchan.lock, flags);
559 
560 	if (vchan_issue_pending(&jzchan->vchan) && !jzchan->desc)
561 		jz4780_dma_begin(jzchan);
562 
563 	spin_unlock_irqrestore(&jzchan->vchan.lock, flags);
564 }
565 
566 static int jz4780_dma_terminate_all(struct dma_chan *chan)
567 {
568 	struct jz4780_dma_chan *jzchan = to_jz4780_dma_chan(chan);
569 	struct jz4780_dma_dev *jzdma = jz4780_dma_chan_parent(jzchan);
570 	unsigned long flags;
571 	LIST_HEAD(head);
572 
573 	spin_lock_irqsave(&jzchan->vchan.lock, flags);
574 
575 	/* Clear the DMA status and stop the transfer. */
576 	jz4780_dma_chn_writel(jzdma, jzchan->id, JZ_DMA_REG_DCS, 0);
577 	if (jzchan->desc) {
578 		vchan_terminate_vdesc(&jzchan->desc->vdesc);
579 		jzchan->desc = NULL;
580 	}
581 
582 	jz4780_dma_chan_disable(jzdma, jzchan->id);
583 
584 	vchan_get_all_descriptors(&jzchan->vchan, &head);
585 
586 	spin_unlock_irqrestore(&jzchan->vchan.lock, flags);
587 
588 	vchan_dma_desc_free_list(&jzchan->vchan, &head);
589 	return 0;
590 }
591 
592 static void jz4780_dma_synchronize(struct dma_chan *chan)
593 {
594 	struct jz4780_dma_chan *jzchan = to_jz4780_dma_chan(chan);
595 	struct jz4780_dma_dev *jzdma = jz4780_dma_chan_parent(jzchan);
596 
597 	vchan_synchronize(&jzchan->vchan);
598 	jz4780_dma_chan_disable(jzdma, jzchan->id);
599 }
600 
601 static int jz4780_dma_config(struct dma_chan *chan,
602 	struct dma_slave_config *config)
603 {
604 	struct jz4780_dma_chan *jzchan = to_jz4780_dma_chan(chan);
605 
606 	if ((config->src_addr_width == DMA_SLAVE_BUSWIDTH_8_BYTES)
607 	   || (config->dst_addr_width == DMA_SLAVE_BUSWIDTH_8_BYTES))
608 		return -EINVAL;
609 
610 	/* Copy the reset of the slave configuration, it is used later. */
611 	memcpy(&jzchan->config, config, sizeof(jzchan->config));
612 
613 	return 0;
614 }
615 
616 static size_t jz4780_dma_desc_residue(struct jz4780_dma_chan *jzchan,
617 	struct jz4780_dma_desc *desc, unsigned int next_sg)
618 {
619 	struct jz4780_dma_dev *jzdma = jz4780_dma_chan_parent(jzchan);
620 	unsigned int count = 0;
621 	unsigned int i;
622 
623 	for (i = next_sg; i < desc->count; i++)
624 		count += desc->desc[i].dtc & GENMASK(23, 0);
625 
626 	if (next_sg != 0)
627 		count += jz4780_dma_chn_readl(jzdma, jzchan->id,
628 					 JZ_DMA_REG_DTC);
629 
630 	return count << jzchan->transfer_shift;
631 }
632 
633 static enum dma_status jz4780_dma_tx_status(struct dma_chan *chan,
634 	dma_cookie_t cookie, struct dma_tx_state *txstate)
635 {
636 	struct jz4780_dma_chan *jzchan = to_jz4780_dma_chan(chan);
637 	struct virt_dma_desc *vdesc;
638 	enum dma_status status;
639 	unsigned long flags;
640 	unsigned long residue = 0;
641 
642 	spin_lock_irqsave(&jzchan->vchan.lock, flags);
643 
644 	status = dma_cookie_status(chan, cookie, txstate);
645 	if ((status == DMA_COMPLETE) || (txstate == NULL))
646 		goto out_unlock_irqrestore;
647 
648 	vdesc = vchan_find_desc(&jzchan->vchan, cookie);
649 	if (vdesc) {
650 		/* On the issued list, so hasn't been processed yet */
651 		residue = jz4780_dma_desc_residue(jzchan,
652 					to_jz4780_dma_desc(vdesc), 0);
653 	} else if (cookie == jzchan->desc->vdesc.tx.cookie) {
654 		residue = jz4780_dma_desc_residue(jzchan, jzchan->desc,
655 					jzchan->curr_hwdesc + 1);
656 	}
657 	dma_set_residue(txstate, residue);
658 
659 	if (vdesc && jzchan->desc && vdesc == &jzchan->desc->vdesc
660 	    && jzchan->desc->status & (JZ_DMA_DCS_AR | JZ_DMA_DCS_HLT))
661 		status = DMA_ERROR;
662 
663 out_unlock_irqrestore:
664 	spin_unlock_irqrestore(&jzchan->vchan.lock, flags);
665 	return status;
666 }
667 
668 static bool jz4780_dma_chan_irq(struct jz4780_dma_dev *jzdma,
669 				struct jz4780_dma_chan *jzchan)
670 {
671 	const unsigned int soc_flags = jzdma->soc_data->flags;
672 	struct jz4780_dma_desc *desc = jzchan->desc;
673 	uint32_t dcs;
674 	bool ack = true;
675 
676 	spin_lock(&jzchan->vchan.lock);
677 
678 	dcs = jz4780_dma_chn_readl(jzdma, jzchan->id, JZ_DMA_REG_DCS);
679 	jz4780_dma_chn_writel(jzdma, jzchan->id, JZ_DMA_REG_DCS, 0);
680 
681 	if (dcs & JZ_DMA_DCS_AR) {
682 		dev_warn(&jzchan->vchan.chan.dev->device,
683 			 "address error (DCS=0x%x)\n", dcs);
684 	}
685 
686 	if (dcs & JZ_DMA_DCS_HLT) {
687 		dev_warn(&jzchan->vchan.chan.dev->device,
688 			 "channel halt (DCS=0x%x)\n", dcs);
689 	}
690 
691 	if (jzchan->desc) {
692 		jzchan->desc->status = dcs;
693 
694 		if ((dcs & (JZ_DMA_DCS_AR | JZ_DMA_DCS_HLT)) == 0) {
695 			if (jzchan->desc->type == DMA_CYCLIC) {
696 				vchan_cyclic_callback(&jzchan->desc->vdesc);
697 
698 				jz4780_dma_begin(jzchan);
699 			} else if (dcs & JZ_DMA_DCS_TT) {
700 				if (!(soc_flags & JZ_SOC_DATA_BREAK_LINKS) ||
701 				    (jzchan->curr_hwdesc + 1 == desc->count)) {
702 					vchan_cookie_complete(&desc->vdesc);
703 					jzchan->desc = NULL;
704 				}
705 
706 				jz4780_dma_begin(jzchan);
707 			} else {
708 				/* False positive - continue the transfer */
709 				ack = false;
710 				jz4780_dma_chn_writel(jzdma, jzchan->id,
711 						      JZ_DMA_REG_DCS,
712 						      JZ_DMA_DCS_CTE);
713 			}
714 		}
715 	} else {
716 		dev_err(&jzchan->vchan.chan.dev->device,
717 			"channel IRQ with no active transfer\n");
718 	}
719 
720 	spin_unlock(&jzchan->vchan.lock);
721 
722 	return ack;
723 }
724 
725 static irqreturn_t jz4780_dma_irq_handler(int irq, void *data)
726 {
727 	struct jz4780_dma_dev *jzdma = data;
728 	unsigned int nb_channels = jzdma->soc_data->nb_channels;
729 	unsigned long pending;
730 	uint32_t dmac;
731 	int i;
732 
733 	pending = jz4780_dma_ctrl_readl(jzdma, JZ_DMA_REG_DIRQP);
734 
735 	for_each_set_bit(i, &pending, nb_channels) {
736 		if (jz4780_dma_chan_irq(jzdma, &jzdma->chan[i]))
737 			pending &= ~BIT(i);
738 	}
739 
740 	/* Clear halt and address error status of all channels. */
741 	dmac = jz4780_dma_ctrl_readl(jzdma, JZ_DMA_REG_DMAC);
742 	dmac &= ~(JZ_DMA_DMAC_HLT | JZ_DMA_DMAC_AR);
743 	jz4780_dma_ctrl_writel(jzdma, JZ_DMA_REG_DMAC, dmac);
744 
745 	/* Clear interrupt pending status. */
746 	jz4780_dma_ctrl_writel(jzdma, JZ_DMA_REG_DIRQP, pending);
747 
748 	return IRQ_HANDLED;
749 }
750 
751 static int jz4780_dma_alloc_chan_resources(struct dma_chan *chan)
752 {
753 	struct jz4780_dma_chan *jzchan = to_jz4780_dma_chan(chan);
754 
755 	jzchan->desc_pool = dma_pool_create(dev_name(&chan->dev->device),
756 					    chan->device->dev,
757 					    JZ_DMA_DESC_BLOCK_SIZE,
758 					    PAGE_SIZE, 0);
759 	if (!jzchan->desc_pool) {
760 		dev_err(&chan->dev->device,
761 			"failed to allocate descriptor pool\n");
762 		return -ENOMEM;
763 	}
764 
765 	return 0;
766 }
767 
768 static void jz4780_dma_free_chan_resources(struct dma_chan *chan)
769 {
770 	struct jz4780_dma_chan *jzchan = to_jz4780_dma_chan(chan);
771 
772 	vchan_free_chan_resources(&jzchan->vchan);
773 	dma_pool_destroy(jzchan->desc_pool);
774 	jzchan->desc_pool = NULL;
775 }
776 
777 static bool jz4780_dma_filter_fn(struct dma_chan *chan, void *param)
778 {
779 	struct jz4780_dma_chan *jzchan = to_jz4780_dma_chan(chan);
780 	struct jz4780_dma_dev *jzdma = jz4780_dma_chan_parent(jzchan);
781 	struct jz4780_dma_filter_data *data = param;
782 
783 
784 	if (data->channel > -1) {
785 		if (data->channel != jzchan->id)
786 			return false;
787 	} else if (jzdma->chan_reserved & BIT(jzchan->id)) {
788 		return false;
789 	}
790 
791 	jzchan->transfer_type = data->transfer_type;
792 
793 	return true;
794 }
795 
796 static struct dma_chan *jz4780_of_dma_xlate(struct of_phandle_args *dma_spec,
797 	struct of_dma *ofdma)
798 {
799 	struct jz4780_dma_dev *jzdma = ofdma->of_dma_data;
800 	dma_cap_mask_t mask = jzdma->dma_device.cap_mask;
801 	struct jz4780_dma_filter_data data;
802 
803 	if (dma_spec->args_count != 2)
804 		return NULL;
805 
806 	data.transfer_type = dma_spec->args[0];
807 	data.channel = dma_spec->args[1];
808 
809 	if (data.channel > -1) {
810 		if (data.channel >= jzdma->soc_data->nb_channels) {
811 			dev_err(jzdma->dma_device.dev,
812 				"device requested non-existent channel %u\n",
813 				data.channel);
814 			return NULL;
815 		}
816 
817 		/* Can only select a channel marked as reserved. */
818 		if (!(jzdma->chan_reserved & BIT(data.channel))) {
819 			dev_err(jzdma->dma_device.dev,
820 				"device requested unreserved channel %u\n",
821 				data.channel);
822 			return NULL;
823 		}
824 
825 		jzdma->chan[data.channel].transfer_type = data.transfer_type;
826 
827 		return dma_get_slave_channel(
828 			&jzdma->chan[data.channel].vchan.chan);
829 	} else {
830 		return __dma_request_channel(&mask, jz4780_dma_filter_fn, &data,
831 					     ofdma->of_node);
832 	}
833 }
834 
835 static int jz4780_dma_probe(struct platform_device *pdev)
836 {
837 	struct device *dev = &pdev->dev;
838 	const struct jz4780_dma_soc_data *soc_data;
839 	struct jz4780_dma_dev *jzdma;
840 	struct jz4780_dma_chan *jzchan;
841 	struct dma_device *dd;
842 	struct resource *res;
843 	int i, ret;
844 
845 	if (!dev->of_node) {
846 		dev_err(dev, "This driver must be probed from devicetree\n");
847 		return -EINVAL;
848 	}
849 
850 	soc_data = device_get_match_data(dev);
851 	if (!soc_data)
852 		return -EINVAL;
853 
854 	jzdma = devm_kzalloc(dev, struct_size(jzdma, chan,
855 			     soc_data->nb_channels), GFP_KERNEL);
856 	if (!jzdma)
857 		return -ENOMEM;
858 
859 	jzdma->soc_data = soc_data;
860 	platform_set_drvdata(pdev, jzdma);
861 
862 	jzdma->chn_base = devm_platform_ioremap_resource(pdev, 0);
863 	if (IS_ERR(jzdma->chn_base))
864 		return PTR_ERR(jzdma->chn_base);
865 
866 	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
867 	if (res) {
868 		jzdma->ctrl_base = devm_ioremap_resource(dev, res);
869 		if (IS_ERR(jzdma->ctrl_base))
870 			return PTR_ERR(jzdma->ctrl_base);
871 	} else if (soc_data->flags & JZ_SOC_DATA_ALLOW_LEGACY_DT) {
872 		/*
873 		 * On JZ4780, if the second memory resource was not supplied,
874 		 * assume we're using an old devicetree, and calculate the
875 		 * offset to the control registers.
876 		 */
877 		jzdma->ctrl_base = jzdma->chn_base + JZ4780_DMA_CTRL_OFFSET;
878 	} else {
879 		dev_err(dev, "failed to get I/O memory\n");
880 		return -EINVAL;
881 	}
882 
883 	jzdma->clk = devm_clk_get(dev, NULL);
884 	if (IS_ERR(jzdma->clk)) {
885 		dev_err(dev, "failed to get clock\n");
886 		ret = PTR_ERR(jzdma->clk);
887 		return ret;
888 	}
889 
890 	clk_prepare_enable(jzdma->clk);
891 
892 	/* Property is optional, if it doesn't exist the value will remain 0. */
893 	of_property_read_u32_index(dev->of_node, "ingenic,reserved-channels",
894 				   0, &jzdma->chan_reserved);
895 
896 	dd = &jzdma->dma_device;
897 
898 	dma_cap_set(DMA_MEMCPY, dd->cap_mask);
899 	dma_cap_set(DMA_SLAVE, dd->cap_mask);
900 	dma_cap_set(DMA_CYCLIC, dd->cap_mask);
901 
902 	dd->dev = dev;
903 	dd->copy_align = DMAENGINE_ALIGN_4_BYTES;
904 	dd->device_alloc_chan_resources = jz4780_dma_alloc_chan_resources;
905 	dd->device_free_chan_resources = jz4780_dma_free_chan_resources;
906 	dd->device_prep_slave_sg = jz4780_dma_prep_slave_sg;
907 	dd->device_prep_dma_cyclic = jz4780_dma_prep_dma_cyclic;
908 	dd->device_prep_dma_memcpy = jz4780_dma_prep_dma_memcpy;
909 	dd->device_config = jz4780_dma_config;
910 	dd->device_terminate_all = jz4780_dma_terminate_all;
911 	dd->device_synchronize = jz4780_dma_synchronize;
912 	dd->device_tx_status = jz4780_dma_tx_status;
913 	dd->device_issue_pending = jz4780_dma_issue_pending;
914 	dd->src_addr_widths = JZ_DMA_BUSWIDTHS;
915 	dd->dst_addr_widths = JZ_DMA_BUSWIDTHS;
916 	dd->directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
917 	dd->residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
918 	dd->max_sg_burst = JZ_DMA_MAX_DESC;
919 
920 	/*
921 	 * Enable DMA controller, mark all channels as not programmable.
922 	 * Also set the FMSC bit - it increases MSC performance, so it makes
923 	 * little sense not to enable it.
924 	 */
925 	jz4780_dma_ctrl_writel(jzdma, JZ_DMA_REG_DMAC, JZ_DMA_DMAC_DMAE |
926 			       JZ_DMA_DMAC_FAIC | JZ_DMA_DMAC_FMSC);
927 
928 	if (soc_data->flags & JZ_SOC_DATA_PROGRAMMABLE_DMA)
929 		jz4780_dma_ctrl_writel(jzdma, JZ_DMA_REG_DMACP, 0);
930 
931 	INIT_LIST_HEAD(&dd->channels);
932 
933 	for (i = 0; i < soc_data->nb_channels; i++) {
934 		jzchan = &jzdma->chan[i];
935 		jzchan->id = i;
936 
937 		vchan_init(&jzchan->vchan, dd);
938 		jzchan->vchan.desc_free = jz4780_dma_desc_free;
939 	}
940 
941 	ret = platform_get_irq(pdev, 0);
942 	if (ret < 0)
943 		goto err_disable_clk;
944 
945 	jzdma->irq = ret;
946 
947 	ret = request_irq(jzdma->irq, jz4780_dma_irq_handler, 0, dev_name(dev),
948 			  jzdma);
949 	if (ret) {
950 		dev_err(dev, "failed to request IRQ %u!\n", jzdma->irq);
951 		goto err_disable_clk;
952 	}
953 
954 	ret = dmaenginem_async_device_register(dd);
955 	if (ret) {
956 		dev_err(dev, "failed to register device\n");
957 		goto err_free_irq;
958 	}
959 
960 	/* Register with OF DMA helpers. */
961 	ret = of_dma_controller_register(dev->of_node, jz4780_of_dma_xlate,
962 					 jzdma);
963 	if (ret) {
964 		dev_err(dev, "failed to register OF DMA controller\n");
965 		goto err_free_irq;
966 	}
967 
968 	dev_info(dev, "JZ4780 DMA controller initialised\n");
969 	return 0;
970 
971 err_free_irq:
972 	free_irq(jzdma->irq, jzdma);
973 
974 err_disable_clk:
975 	clk_disable_unprepare(jzdma->clk);
976 	return ret;
977 }
978 
979 static int jz4780_dma_remove(struct platform_device *pdev)
980 {
981 	struct jz4780_dma_dev *jzdma = platform_get_drvdata(pdev);
982 	int i;
983 
984 	of_dma_controller_free(pdev->dev.of_node);
985 
986 	clk_disable_unprepare(jzdma->clk);
987 	free_irq(jzdma->irq, jzdma);
988 
989 	for (i = 0; i < jzdma->soc_data->nb_channels; i++)
990 		tasklet_kill(&jzdma->chan[i].vchan.task);
991 
992 	return 0;
993 }
994 
995 static const struct jz4780_dma_soc_data jz4740_dma_soc_data = {
996 	.nb_channels = 6,
997 	.transfer_ord_max = 5,
998 	.flags = JZ_SOC_DATA_BREAK_LINKS,
999 };
1000 
1001 static const struct jz4780_dma_soc_data jz4725b_dma_soc_data = {
1002 	.nb_channels = 6,
1003 	.transfer_ord_max = 5,
1004 	.flags = JZ_SOC_DATA_PER_CHAN_PM | JZ_SOC_DATA_NO_DCKES_DCKEC |
1005 		 JZ_SOC_DATA_BREAK_LINKS,
1006 };
1007 
1008 static const struct jz4780_dma_soc_data jz4760_dma_soc_data = {
1009 	.nb_channels = 5,
1010 	.transfer_ord_max = 6,
1011 	.flags = JZ_SOC_DATA_PER_CHAN_PM | JZ_SOC_DATA_NO_DCKES_DCKEC,
1012 };
1013 
1014 static const struct jz4780_dma_soc_data jz4760b_dma_soc_data = {
1015 	.nb_channels = 5,
1016 	.transfer_ord_max = 6,
1017 	.flags = JZ_SOC_DATA_PER_CHAN_PM,
1018 };
1019 
1020 static const struct jz4780_dma_soc_data jz4770_dma_soc_data = {
1021 	.nb_channels = 6,
1022 	.transfer_ord_max = 6,
1023 	.flags = JZ_SOC_DATA_PER_CHAN_PM,
1024 };
1025 
1026 static const struct jz4780_dma_soc_data jz4780_dma_soc_data = {
1027 	.nb_channels = 32,
1028 	.transfer_ord_max = 7,
1029 	.flags = JZ_SOC_DATA_ALLOW_LEGACY_DT | JZ_SOC_DATA_PROGRAMMABLE_DMA,
1030 };
1031 
1032 static const struct jz4780_dma_soc_data x1000_dma_soc_data = {
1033 	.nb_channels = 8,
1034 	.transfer_ord_max = 7,
1035 	.flags = JZ_SOC_DATA_PROGRAMMABLE_DMA,
1036 };
1037 
1038 static const struct jz4780_dma_soc_data x1830_dma_soc_data = {
1039 	.nb_channels = 32,
1040 	.transfer_ord_max = 7,
1041 	.flags = JZ_SOC_DATA_PROGRAMMABLE_DMA,
1042 };
1043 
1044 static const struct of_device_id jz4780_dma_dt_match[] = {
1045 	{ .compatible = "ingenic,jz4740-dma", .data = &jz4740_dma_soc_data },
1046 	{ .compatible = "ingenic,jz4725b-dma", .data = &jz4725b_dma_soc_data },
1047 	{ .compatible = "ingenic,jz4760-dma", .data = &jz4760_dma_soc_data },
1048 	{ .compatible = "ingenic,jz4760b-dma", .data = &jz4760b_dma_soc_data },
1049 	{ .compatible = "ingenic,jz4770-dma", .data = &jz4770_dma_soc_data },
1050 	{ .compatible = "ingenic,jz4780-dma", .data = &jz4780_dma_soc_data },
1051 	{ .compatible = "ingenic,x1000-dma", .data = &x1000_dma_soc_data },
1052 	{ .compatible = "ingenic,x1830-dma", .data = &x1830_dma_soc_data },
1053 	{},
1054 };
1055 MODULE_DEVICE_TABLE(of, jz4780_dma_dt_match);
1056 
1057 static struct platform_driver jz4780_dma_driver = {
1058 	.probe		= jz4780_dma_probe,
1059 	.remove		= jz4780_dma_remove,
1060 	.driver	= {
1061 		.name	= "jz4780-dma",
1062 		.of_match_table = jz4780_dma_dt_match,
1063 	},
1064 };
1065 
1066 static int __init jz4780_dma_init(void)
1067 {
1068 	return platform_driver_register(&jz4780_dma_driver);
1069 }
1070 subsys_initcall(jz4780_dma_init);
1071 
1072 static void __exit jz4780_dma_exit(void)
1073 {
1074 	platform_driver_unregister(&jz4780_dma_driver);
1075 }
1076 module_exit(jz4780_dma_exit);
1077 
1078 MODULE_AUTHOR("Alex Smith <alex@alex-smith.me.uk>");
1079 MODULE_DESCRIPTION("Ingenic JZ4780 DMA controller driver");
1080 MODULE_LICENSE("GPL");
1081