xref: /openbmc/linux/drivers/dma/sa11x0-dma.c (revision db181ce0)
1 /*
2  * SA11x0 DMAengine support
3  *
4  * Copyright (C) 2012 Russell King
5  *   Derived in part from arch/arm/mach-sa1100/dma.c,
6  *   Copyright (C) 2000, 2001 by Nicolas Pitre
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License version 2 as
10  * published by the Free Software Foundation.
11  */
12 #include <linux/sched.h>
13 #include <linux/device.h>
14 #include <linux/dmaengine.h>
15 #include <linux/init.h>
16 #include <linux/interrupt.h>
17 #include <linux/kernel.h>
18 #include <linux/module.h>
19 #include <linux/platform_device.h>
20 #include <linux/sa11x0-dma.h>
21 #include <linux/slab.h>
22 #include <linux/spinlock.h>
23 
24 #include "virt-dma.h"
25 
26 #define NR_PHY_CHAN	6
27 #define DMA_ALIGN	3
28 #define DMA_MAX_SIZE	0x1fff
29 #define DMA_CHUNK_SIZE	0x1000
30 
31 #define DMA_DDAR	0x00
32 #define DMA_DCSR_S	0x04
33 #define DMA_DCSR_C	0x08
34 #define DMA_DCSR_R	0x0c
35 #define DMA_DBSA	0x10
36 #define DMA_DBTA	0x14
37 #define DMA_DBSB	0x18
38 #define DMA_DBTB	0x1c
39 #define DMA_SIZE	0x20
40 
41 #define DCSR_RUN	(1 << 0)
42 #define DCSR_IE		(1 << 1)
43 #define DCSR_ERROR	(1 << 2)
44 #define DCSR_DONEA	(1 << 3)
45 #define DCSR_STRTA	(1 << 4)
46 #define DCSR_DONEB	(1 << 5)
47 #define DCSR_STRTB	(1 << 6)
48 #define DCSR_BIU	(1 << 7)
49 
50 #define DDAR_RW		(1 << 0)	/* 0 = W, 1 = R */
51 #define DDAR_E		(1 << 1)	/* 0 = LE, 1 = BE */
52 #define DDAR_BS		(1 << 2)	/* 0 = BS4, 1 = BS8 */
53 #define DDAR_DW		(1 << 3)	/* 0 = 8b, 1 = 16b */
54 #define DDAR_Ser0UDCTr	(0x0 << 4)
55 #define DDAR_Ser0UDCRc	(0x1 << 4)
56 #define DDAR_Ser1SDLCTr	(0x2 << 4)
57 #define DDAR_Ser1SDLCRc	(0x3 << 4)
58 #define DDAR_Ser1UARTTr	(0x4 << 4)
59 #define DDAR_Ser1UARTRc	(0x5 << 4)
60 #define DDAR_Ser2ICPTr	(0x6 << 4)
61 #define DDAR_Ser2ICPRc	(0x7 << 4)
62 #define DDAR_Ser3UARTTr	(0x8 << 4)
63 #define DDAR_Ser3UARTRc	(0x9 << 4)
64 #define DDAR_Ser4MCP0Tr	(0xa << 4)
65 #define DDAR_Ser4MCP0Rc	(0xb << 4)
66 #define DDAR_Ser4MCP1Tr	(0xc << 4)
67 #define DDAR_Ser4MCP1Rc	(0xd << 4)
68 #define DDAR_Ser4SSPTr	(0xe << 4)
69 #define DDAR_Ser4SSPRc	(0xf << 4)
70 
71 struct sa11x0_dma_sg {
72 	u32			addr;
73 	u32			len;
74 };
75 
76 struct sa11x0_dma_desc {
77 	struct virt_dma_desc	vd;
78 
79 	u32			ddar;
80 	size_t			size;
81 	unsigned		period;
82 	bool			cyclic;
83 
84 	unsigned		sglen;
85 	struct sa11x0_dma_sg	sg[0];
86 };
87 
88 struct sa11x0_dma_phy;
89 
90 struct sa11x0_dma_chan {
91 	struct virt_dma_chan	vc;
92 
93 	/* protected by c->vc.lock */
94 	struct sa11x0_dma_phy	*phy;
95 	enum dma_status		status;
96 
97 	/* protected by d->lock */
98 	struct list_head	node;
99 
100 	u32			ddar;
101 	const char		*name;
102 };
103 
104 struct sa11x0_dma_phy {
105 	void __iomem		*base;
106 	struct sa11x0_dma_dev	*dev;
107 	unsigned		num;
108 
109 	struct sa11x0_dma_chan	*vchan;
110 
111 	/* Protected by c->vc.lock */
112 	unsigned		sg_load;
113 	struct sa11x0_dma_desc	*txd_load;
114 	unsigned		sg_done;
115 	struct sa11x0_dma_desc	*txd_done;
116 	u32			dbs[2];
117 	u32			dbt[2];
118 	u32			dcsr;
119 };
120 
121 struct sa11x0_dma_dev {
122 	struct dma_device	slave;
123 	void __iomem		*base;
124 	spinlock_t		lock;
125 	struct tasklet_struct	task;
126 	struct list_head	chan_pending;
127 	struct sa11x0_dma_phy	phy[NR_PHY_CHAN];
128 };
129 
130 static struct sa11x0_dma_chan *to_sa11x0_dma_chan(struct dma_chan *chan)
131 {
132 	return container_of(chan, struct sa11x0_dma_chan, vc.chan);
133 }
134 
135 static struct sa11x0_dma_dev *to_sa11x0_dma(struct dma_device *dmadev)
136 {
137 	return container_of(dmadev, struct sa11x0_dma_dev, slave);
138 }
139 
140 static struct sa11x0_dma_desc *sa11x0_dma_next_desc(struct sa11x0_dma_chan *c)
141 {
142 	struct virt_dma_desc *vd = vchan_next_desc(&c->vc);
143 
144 	return vd ? container_of(vd, struct sa11x0_dma_desc, vd) : NULL;
145 }
146 
147 static void sa11x0_dma_free_desc(struct virt_dma_desc *vd)
148 {
149 	kfree(container_of(vd, struct sa11x0_dma_desc, vd));
150 }
151 
152 static void sa11x0_dma_start_desc(struct sa11x0_dma_phy *p, struct sa11x0_dma_desc *txd)
153 {
154 	list_del(&txd->vd.node);
155 	p->txd_load = txd;
156 	p->sg_load = 0;
157 
158 	dev_vdbg(p->dev->slave.dev, "pchan %u: txd %p[%x]: starting: DDAR:%x\n",
159 		p->num, &txd->vd, txd->vd.tx.cookie, txd->ddar);
160 }
161 
162 static void noinline sa11x0_dma_start_sg(struct sa11x0_dma_phy *p,
163 	struct sa11x0_dma_chan *c)
164 {
165 	struct sa11x0_dma_desc *txd = p->txd_load;
166 	struct sa11x0_dma_sg *sg;
167 	void __iomem *base = p->base;
168 	unsigned dbsx, dbtx;
169 	u32 dcsr;
170 
171 	if (!txd)
172 		return;
173 
174 	dcsr = readl_relaxed(base + DMA_DCSR_R);
175 
176 	/* Don't try to load the next transfer if both buffers are started */
177 	if ((dcsr & (DCSR_STRTA | DCSR_STRTB)) == (DCSR_STRTA | DCSR_STRTB))
178 		return;
179 
180 	if (p->sg_load == txd->sglen) {
181 		if (!txd->cyclic) {
182 			struct sa11x0_dma_desc *txn = sa11x0_dma_next_desc(c);
183 
184 			/*
185 			 * We have reached the end of the current descriptor.
186 			 * Peek at the next descriptor, and if compatible with
187 			 * the current, start processing it.
188 			 */
189 			if (txn && txn->ddar == txd->ddar) {
190 				txd = txn;
191 				sa11x0_dma_start_desc(p, txn);
192 			} else {
193 				p->txd_load = NULL;
194 				return;
195 			}
196 		} else {
197 			/* Cyclic: reset back to beginning */
198 			p->sg_load = 0;
199 		}
200 	}
201 
202 	sg = &txd->sg[p->sg_load++];
203 
204 	/* Select buffer to load according to channel status */
205 	if (((dcsr & (DCSR_BIU | DCSR_STRTB)) == (DCSR_BIU | DCSR_STRTB)) ||
206 	    ((dcsr & (DCSR_BIU | DCSR_STRTA)) == 0)) {
207 		dbsx = DMA_DBSA;
208 		dbtx = DMA_DBTA;
209 		dcsr = DCSR_STRTA | DCSR_IE | DCSR_RUN;
210 	} else {
211 		dbsx = DMA_DBSB;
212 		dbtx = DMA_DBTB;
213 		dcsr = DCSR_STRTB | DCSR_IE | DCSR_RUN;
214 	}
215 
216 	writel_relaxed(sg->addr, base + dbsx);
217 	writel_relaxed(sg->len, base + dbtx);
218 	writel(dcsr, base + DMA_DCSR_S);
219 
220 	dev_dbg(p->dev->slave.dev, "pchan %u: load: DCSR:%02x DBS%c:%08x DBT%c:%08x\n",
221 		p->num, dcsr,
222 		'A' + (dbsx == DMA_DBSB), sg->addr,
223 		'A' + (dbtx == DMA_DBTB), sg->len);
224 }
225 
226 static void noinline sa11x0_dma_complete(struct sa11x0_dma_phy *p,
227 	struct sa11x0_dma_chan *c)
228 {
229 	struct sa11x0_dma_desc *txd = p->txd_done;
230 
231 	if (++p->sg_done == txd->sglen) {
232 		if (!txd->cyclic) {
233 			vchan_cookie_complete(&txd->vd);
234 
235 			p->sg_done = 0;
236 			p->txd_done = p->txd_load;
237 
238 			if (!p->txd_done)
239 				tasklet_schedule(&p->dev->task);
240 		} else {
241 			if ((p->sg_done % txd->period) == 0)
242 				vchan_cyclic_callback(&txd->vd);
243 
244 			/* Cyclic: reset back to beginning */
245 			p->sg_done = 0;
246 		}
247 	}
248 
249 	sa11x0_dma_start_sg(p, c);
250 }
251 
252 static irqreturn_t sa11x0_dma_irq(int irq, void *dev_id)
253 {
254 	struct sa11x0_dma_phy *p = dev_id;
255 	struct sa11x0_dma_dev *d = p->dev;
256 	struct sa11x0_dma_chan *c;
257 	u32 dcsr;
258 
259 	dcsr = readl_relaxed(p->base + DMA_DCSR_R);
260 	if (!(dcsr & (DCSR_ERROR | DCSR_DONEA | DCSR_DONEB)))
261 		return IRQ_NONE;
262 
263 	/* Clear reported status bits */
264 	writel_relaxed(dcsr & (DCSR_ERROR | DCSR_DONEA | DCSR_DONEB),
265 		p->base + DMA_DCSR_C);
266 
267 	dev_dbg(d->slave.dev, "pchan %u: irq: DCSR:%02x\n", p->num, dcsr);
268 
269 	if (dcsr & DCSR_ERROR) {
270 		dev_err(d->slave.dev, "pchan %u: error. DCSR:%02x DDAR:%08x DBSA:%08x DBTA:%08x DBSB:%08x DBTB:%08x\n",
271 			p->num, dcsr,
272 			readl_relaxed(p->base + DMA_DDAR),
273 			readl_relaxed(p->base + DMA_DBSA),
274 			readl_relaxed(p->base + DMA_DBTA),
275 			readl_relaxed(p->base + DMA_DBSB),
276 			readl_relaxed(p->base + DMA_DBTB));
277 	}
278 
279 	c = p->vchan;
280 	if (c) {
281 		unsigned long flags;
282 
283 		spin_lock_irqsave(&c->vc.lock, flags);
284 		/*
285 		 * Now that we're holding the lock, check that the vchan
286 		 * really is associated with this pchan before touching the
287 		 * hardware.  This should always succeed, because we won't
288 		 * change p->vchan or c->phy while the channel is actively
289 		 * transferring.
290 		 */
291 		if (c->phy == p) {
292 			if (dcsr & DCSR_DONEA)
293 				sa11x0_dma_complete(p, c);
294 			if (dcsr & DCSR_DONEB)
295 				sa11x0_dma_complete(p, c);
296 		}
297 		spin_unlock_irqrestore(&c->vc.lock, flags);
298 	}
299 
300 	return IRQ_HANDLED;
301 }
302 
303 static void sa11x0_dma_start_txd(struct sa11x0_dma_chan *c)
304 {
305 	struct sa11x0_dma_desc *txd = sa11x0_dma_next_desc(c);
306 
307 	/* If the issued list is empty, we have no further txds to process */
308 	if (txd) {
309 		struct sa11x0_dma_phy *p = c->phy;
310 
311 		sa11x0_dma_start_desc(p, txd);
312 		p->txd_done = txd;
313 		p->sg_done = 0;
314 
315 		/* The channel should not have any transfers started */
316 		WARN_ON(readl_relaxed(p->base + DMA_DCSR_R) &
317 				      (DCSR_STRTA | DCSR_STRTB));
318 
319 		/* Clear the run and start bits before changing DDAR */
320 		writel_relaxed(DCSR_RUN | DCSR_STRTA | DCSR_STRTB,
321 			       p->base + DMA_DCSR_C);
322 		writel_relaxed(txd->ddar, p->base + DMA_DDAR);
323 
324 		/* Try to start both buffers */
325 		sa11x0_dma_start_sg(p, c);
326 		sa11x0_dma_start_sg(p, c);
327 	}
328 }
329 
330 static void sa11x0_dma_tasklet(unsigned long arg)
331 {
332 	struct sa11x0_dma_dev *d = (struct sa11x0_dma_dev *)arg;
333 	struct sa11x0_dma_phy *p;
334 	struct sa11x0_dma_chan *c;
335 	unsigned pch, pch_alloc = 0;
336 
337 	dev_dbg(d->slave.dev, "tasklet enter\n");
338 
339 	list_for_each_entry(c, &d->slave.channels, vc.chan.device_node) {
340 		spin_lock_irq(&c->vc.lock);
341 		p = c->phy;
342 		if (p && !p->txd_done) {
343 			sa11x0_dma_start_txd(c);
344 			if (!p->txd_done) {
345 				/* No current txd associated with this channel */
346 				dev_dbg(d->slave.dev, "pchan %u: free\n", p->num);
347 
348 				/* Mark this channel free */
349 				c->phy = NULL;
350 				p->vchan = NULL;
351 			}
352 		}
353 		spin_unlock_irq(&c->vc.lock);
354 	}
355 
356 	spin_lock_irq(&d->lock);
357 	for (pch = 0; pch < NR_PHY_CHAN; pch++) {
358 		p = &d->phy[pch];
359 
360 		if (p->vchan == NULL && !list_empty(&d->chan_pending)) {
361 			c = list_first_entry(&d->chan_pending,
362 				struct sa11x0_dma_chan, node);
363 			list_del_init(&c->node);
364 
365 			pch_alloc |= 1 << pch;
366 
367 			/* Mark this channel allocated */
368 			p->vchan = c;
369 
370 			dev_dbg(d->slave.dev, "pchan %u: alloc vchan %p\n", pch, &c->vc);
371 		}
372 	}
373 	spin_unlock_irq(&d->lock);
374 
375 	for (pch = 0; pch < NR_PHY_CHAN; pch++) {
376 		if (pch_alloc & (1 << pch)) {
377 			p = &d->phy[pch];
378 			c = p->vchan;
379 
380 			spin_lock_irq(&c->vc.lock);
381 			c->phy = p;
382 
383 			sa11x0_dma_start_txd(c);
384 			spin_unlock_irq(&c->vc.lock);
385 		}
386 	}
387 
388 	dev_dbg(d->slave.dev, "tasklet exit\n");
389 }
390 
391 
392 static int sa11x0_dma_alloc_chan_resources(struct dma_chan *chan)
393 {
394 	return 0;
395 }
396 
397 static void sa11x0_dma_free_chan_resources(struct dma_chan *chan)
398 {
399 	struct sa11x0_dma_chan *c = to_sa11x0_dma_chan(chan);
400 	struct sa11x0_dma_dev *d = to_sa11x0_dma(chan->device);
401 	unsigned long flags;
402 
403 	spin_lock_irqsave(&d->lock, flags);
404 	list_del_init(&c->node);
405 	spin_unlock_irqrestore(&d->lock, flags);
406 
407 	vchan_free_chan_resources(&c->vc);
408 }
409 
410 static dma_addr_t sa11x0_dma_pos(struct sa11x0_dma_phy *p)
411 {
412 	unsigned reg;
413 	u32 dcsr;
414 
415 	dcsr = readl_relaxed(p->base + DMA_DCSR_R);
416 
417 	if ((dcsr & (DCSR_BIU | DCSR_STRTA)) == DCSR_STRTA ||
418 	    (dcsr & (DCSR_BIU | DCSR_STRTB)) == DCSR_BIU)
419 		reg = DMA_DBSA;
420 	else
421 		reg = DMA_DBSB;
422 
423 	return readl_relaxed(p->base + reg);
424 }
425 
426 static enum dma_status sa11x0_dma_tx_status(struct dma_chan *chan,
427 	dma_cookie_t cookie, struct dma_tx_state *state)
428 {
429 	struct sa11x0_dma_chan *c = to_sa11x0_dma_chan(chan);
430 	struct sa11x0_dma_dev *d = to_sa11x0_dma(chan->device);
431 	struct sa11x0_dma_phy *p;
432 	struct virt_dma_desc *vd;
433 	unsigned long flags;
434 	enum dma_status ret;
435 
436 	ret = dma_cookie_status(&c->vc.chan, cookie, state);
437 	if (ret == DMA_COMPLETE)
438 		return ret;
439 
440 	if (!state)
441 		return c->status;
442 
443 	spin_lock_irqsave(&c->vc.lock, flags);
444 	p = c->phy;
445 
446 	/*
447 	 * If the cookie is on our issue queue, then the residue is
448 	 * its total size.
449 	 */
450 	vd = vchan_find_desc(&c->vc, cookie);
451 	if (vd) {
452 		state->residue = container_of(vd, struct sa11x0_dma_desc, vd)->size;
453 	} else if (!p) {
454 		state->residue = 0;
455 	} else {
456 		struct sa11x0_dma_desc *txd;
457 		size_t bytes = 0;
458 
459 		if (p->txd_done && p->txd_done->vd.tx.cookie == cookie)
460 			txd = p->txd_done;
461 		else if (p->txd_load && p->txd_load->vd.tx.cookie == cookie)
462 			txd = p->txd_load;
463 		else
464 			txd = NULL;
465 
466 		ret = c->status;
467 		if (txd) {
468 			dma_addr_t addr = sa11x0_dma_pos(p);
469 			unsigned i;
470 
471 			dev_vdbg(d->slave.dev, "tx_status: addr:%x\n", addr);
472 
473 			for (i = 0; i < txd->sglen; i++) {
474 				dev_vdbg(d->slave.dev, "tx_status: [%u] %x+%x\n",
475 					i, txd->sg[i].addr, txd->sg[i].len);
476 				if (addr >= txd->sg[i].addr &&
477 				    addr < txd->sg[i].addr + txd->sg[i].len) {
478 					unsigned len;
479 
480 					len = txd->sg[i].len -
481 						(addr - txd->sg[i].addr);
482 					dev_vdbg(d->slave.dev, "tx_status: [%u] +%x\n",
483 						i, len);
484 					bytes += len;
485 					i++;
486 					break;
487 				}
488 			}
489 			for (; i < txd->sglen; i++) {
490 				dev_vdbg(d->slave.dev, "tx_status: [%u] %x+%x ++\n",
491 					i, txd->sg[i].addr, txd->sg[i].len);
492 				bytes += txd->sg[i].len;
493 			}
494 		}
495 		state->residue = bytes;
496 	}
497 	spin_unlock_irqrestore(&c->vc.lock, flags);
498 
499 	dev_vdbg(d->slave.dev, "tx_status: bytes 0x%zx\n", state->residue);
500 
501 	return ret;
502 }
503 
504 /*
505  * Move pending txds to the issued list, and re-init pending list.
506  * If not already pending, add this channel to the list of pending
507  * channels and trigger the tasklet to run.
508  */
509 static void sa11x0_dma_issue_pending(struct dma_chan *chan)
510 {
511 	struct sa11x0_dma_chan *c = to_sa11x0_dma_chan(chan);
512 	struct sa11x0_dma_dev *d = to_sa11x0_dma(chan->device);
513 	unsigned long flags;
514 
515 	spin_lock_irqsave(&c->vc.lock, flags);
516 	if (vchan_issue_pending(&c->vc)) {
517 		if (!c->phy) {
518 			spin_lock(&d->lock);
519 			if (list_empty(&c->node)) {
520 				list_add_tail(&c->node, &d->chan_pending);
521 				tasklet_schedule(&d->task);
522 				dev_dbg(d->slave.dev, "vchan %p: issued\n", &c->vc);
523 			}
524 			spin_unlock(&d->lock);
525 		}
526 	} else
527 		dev_dbg(d->slave.dev, "vchan %p: nothing to issue\n", &c->vc);
528 	spin_unlock_irqrestore(&c->vc.lock, flags);
529 }
530 
531 static struct dma_async_tx_descriptor *sa11x0_dma_prep_slave_sg(
532 	struct dma_chan *chan, struct scatterlist *sg, unsigned int sglen,
533 	enum dma_transfer_direction dir, unsigned long flags, void *context)
534 {
535 	struct sa11x0_dma_chan *c = to_sa11x0_dma_chan(chan);
536 	struct sa11x0_dma_desc *txd;
537 	struct scatterlist *sgent;
538 	unsigned i, j = sglen;
539 	size_t size = 0;
540 
541 	/* SA11x0 channels can only operate in their native direction */
542 	if (dir != (c->ddar & DDAR_RW ? DMA_DEV_TO_MEM : DMA_MEM_TO_DEV)) {
543 		dev_err(chan->device->dev, "vchan %p: bad DMA direction: DDAR:%08x dir:%u\n",
544 			&c->vc, c->ddar, dir);
545 		return NULL;
546 	}
547 
548 	/* Do not allow zero-sized txds */
549 	if (sglen == 0)
550 		return NULL;
551 
552 	for_each_sg(sg, sgent, sglen, i) {
553 		dma_addr_t addr = sg_dma_address(sgent);
554 		unsigned int len = sg_dma_len(sgent);
555 
556 		if (len > DMA_MAX_SIZE)
557 			j += DIV_ROUND_UP(len, DMA_MAX_SIZE & ~DMA_ALIGN) - 1;
558 		if (addr & DMA_ALIGN) {
559 			dev_dbg(chan->device->dev, "vchan %p: bad buffer alignment: %08x\n",
560 				&c->vc, addr);
561 			return NULL;
562 		}
563 	}
564 
565 	txd = kzalloc(sizeof(*txd) + j * sizeof(txd->sg[0]), GFP_ATOMIC);
566 	if (!txd) {
567 		dev_dbg(chan->device->dev, "vchan %p: kzalloc failed\n", &c->vc);
568 		return NULL;
569 	}
570 
571 	j = 0;
572 	for_each_sg(sg, sgent, sglen, i) {
573 		dma_addr_t addr = sg_dma_address(sgent);
574 		unsigned len = sg_dma_len(sgent);
575 
576 		size += len;
577 
578 		do {
579 			unsigned tlen = len;
580 
581 			/*
582 			 * Check whether the transfer will fit.  If not, try
583 			 * to split the transfer up such that we end up with
584 			 * equal chunks - but make sure that we preserve the
585 			 * alignment.  This avoids small segments.
586 			 */
587 			if (tlen > DMA_MAX_SIZE) {
588 				unsigned mult = DIV_ROUND_UP(tlen,
589 					DMA_MAX_SIZE & ~DMA_ALIGN);
590 
591 				tlen = (tlen / mult) & ~DMA_ALIGN;
592 			}
593 
594 			txd->sg[j].addr = addr;
595 			txd->sg[j].len = tlen;
596 
597 			addr += tlen;
598 			len -= tlen;
599 			j++;
600 		} while (len);
601 	}
602 
603 	txd->ddar = c->ddar;
604 	txd->size = size;
605 	txd->sglen = j;
606 
607 	dev_dbg(chan->device->dev, "vchan %p: txd %p: size %u nr %u\n",
608 		&c->vc, &txd->vd, txd->size, txd->sglen);
609 
610 	return vchan_tx_prep(&c->vc, &txd->vd, flags);
611 }
612 
613 static struct dma_async_tx_descriptor *sa11x0_dma_prep_dma_cyclic(
614 	struct dma_chan *chan, dma_addr_t addr, size_t size, size_t period,
615 	enum dma_transfer_direction dir, unsigned long flags, void *context)
616 {
617 	struct sa11x0_dma_chan *c = to_sa11x0_dma_chan(chan);
618 	struct sa11x0_dma_desc *txd;
619 	unsigned i, j, k, sglen, sgperiod;
620 
621 	/* SA11x0 channels can only operate in their native direction */
622 	if (dir != (c->ddar & DDAR_RW ? DMA_DEV_TO_MEM : DMA_MEM_TO_DEV)) {
623 		dev_err(chan->device->dev, "vchan %p: bad DMA direction: DDAR:%08x dir:%u\n",
624 			&c->vc, c->ddar, dir);
625 		return NULL;
626 	}
627 
628 	sgperiod = DIV_ROUND_UP(period, DMA_MAX_SIZE & ~DMA_ALIGN);
629 	sglen = size * sgperiod / period;
630 
631 	/* Do not allow zero-sized txds */
632 	if (sglen == 0)
633 		return NULL;
634 
635 	txd = kzalloc(sizeof(*txd) + sglen * sizeof(txd->sg[0]), GFP_ATOMIC);
636 	if (!txd) {
637 		dev_dbg(chan->device->dev, "vchan %p: kzalloc failed\n", &c->vc);
638 		return NULL;
639 	}
640 
641 	for (i = k = 0; i < size / period; i++) {
642 		size_t tlen, len = period;
643 
644 		for (j = 0; j < sgperiod; j++, k++) {
645 			tlen = len;
646 
647 			if (tlen > DMA_MAX_SIZE) {
648 				unsigned mult = DIV_ROUND_UP(tlen, DMA_MAX_SIZE & ~DMA_ALIGN);
649 				tlen = (tlen / mult) & ~DMA_ALIGN;
650 			}
651 
652 			txd->sg[k].addr = addr;
653 			txd->sg[k].len = tlen;
654 			addr += tlen;
655 			len -= tlen;
656 		}
657 
658 		WARN_ON(len != 0);
659 	}
660 
661 	WARN_ON(k != sglen);
662 
663 	txd->ddar = c->ddar;
664 	txd->size = size;
665 	txd->sglen = sglen;
666 	txd->cyclic = 1;
667 	txd->period = sgperiod;
668 
669 	return vchan_tx_prep(&c->vc, &txd->vd, DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
670 }
671 
672 static int sa11x0_dma_slave_config(struct sa11x0_dma_chan *c, struct dma_slave_config *cfg)
673 {
674 	u32 ddar = c->ddar & ((0xf << 4) | DDAR_RW);
675 	dma_addr_t addr;
676 	enum dma_slave_buswidth width;
677 	u32 maxburst;
678 
679 	if (ddar & DDAR_RW) {
680 		addr = cfg->src_addr;
681 		width = cfg->src_addr_width;
682 		maxburst = cfg->src_maxburst;
683 	} else {
684 		addr = cfg->dst_addr;
685 		width = cfg->dst_addr_width;
686 		maxburst = cfg->dst_maxburst;
687 	}
688 
689 	if ((width != DMA_SLAVE_BUSWIDTH_1_BYTE &&
690 	     width != DMA_SLAVE_BUSWIDTH_2_BYTES) ||
691 	    (maxburst != 4 && maxburst != 8))
692 		return -EINVAL;
693 
694 	if (width == DMA_SLAVE_BUSWIDTH_2_BYTES)
695 		ddar |= DDAR_DW;
696 	if (maxburst == 8)
697 		ddar |= DDAR_BS;
698 
699 	dev_dbg(c->vc.chan.device->dev, "vchan %p: dma_slave_config addr %x width %u burst %u\n",
700 		&c->vc, addr, width, maxburst);
701 
702 	c->ddar = ddar | (addr & 0xf0000000) | (addr & 0x003ffffc) << 6;
703 
704 	return 0;
705 }
706 
707 static int sa11x0_dma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
708 	unsigned long arg)
709 {
710 	struct sa11x0_dma_chan *c = to_sa11x0_dma_chan(chan);
711 	struct sa11x0_dma_dev *d = to_sa11x0_dma(chan->device);
712 	struct sa11x0_dma_phy *p;
713 	LIST_HEAD(head);
714 	unsigned long flags;
715 	int ret;
716 
717 	switch (cmd) {
718 	case DMA_SLAVE_CONFIG:
719 		return sa11x0_dma_slave_config(c, (struct dma_slave_config *)arg);
720 
721 	case DMA_TERMINATE_ALL:
722 		dev_dbg(d->slave.dev, "vchan %p: terminate all\n", &c->vc);
723 		/* Clear the tx descriptor lists */
724 		spin_lock_irqsave(&c->vc.lock, flags);
725 		vchan_get_all_descriptors(&c->vc, &head);
726 
727 		p = c->phy;
728 		if (p) {
729 			dev_dbg(d->slave.dev, "pchan %u: terminating\n", p->num);
730 			/* vchan is assigned to a pchan - stop the channel */
731 			writel(DCSR_RUN | DCSR_IE |
732 				DCSR_STRTA | DCSR_DONEA |
733 				DCSR_STRTB | DCSR_DONEB,
734 				p->base + DMA_DCSR_C);
735 
736 			if (p->txd_load) {
737 				if (p->txd_load != p->txd_done)
738 					list_add_tail(&p->txd_load->vd.node, &head);
739 				p->txd_load = NULL;
740 			}
741 			if (p->txd_done) {
742 				list_add_tail(&p->txd_done->vd.node, &head);
743 				p->txd_done = NULL;
744 			}
745 			c->phy = NULL;
746 			spin_lock(&d->lock);
747 			p->vchan = NULL;
748 			spin_unlock(&d->lock);
749 			tasklet_schedule(&d->task);
750 		}
751 		spin_unlock_irqrestore(&c->vc.lock, flags);
752 		vchan_dma_desc_free_list(&c->vc, &head);
753 		ret = 0;
754 		break;
755 
756 	case DMA_PAUSE:
757 		dev_dbg(d->slave.dev, "vchan %p: pause\n", &c->vc);
758 		spin_lock_irqsave(&c->vc.lock, flags);
759 		if (c->status == DMA_IN_PROGRESS) {
760 			c->status = DMA_PAUSED;
761 
762 			p = c->phy;
763 			if (p) {
764 				writel(DCSR_RUN | DCSR_IE, p->base + DMA_DCSR_C);
765 			} else {
766 				spin_lock(&d->lock);
767 				list_del_init(&c->node);
768 				spin_unlock(&d->lock);
769 			}
770 		}
771 		spin_unlock_irqrestore(&c->vc.lock, flags);
772 		ret = 0;
773 		break;
774 
775 	case DMA_RESUME:
776 		dev_dbg(d->slave.dev, "vchan %p: resume\n", &c->vc);
777 		spin_lock_irqsave(&c->vc.lock, flags);
778 		if (c->status == DMA_PAUSED) {
779 			c->status = DMA_IN_PROGRESS;
780 
781 			p = c->phy;
782 			if (p) {
783 				writel(DCSR_RUN | DCSR_IE, p->base + DMA_DCSR_S);
784 			} else if (!list_empty(&c->vc.desc_issued)) {
785 				spin_lock(&d->lock);
786 				list_add_tail(&c->node, &d->chan_pending);
787 				spin_unlock(&d->lock);
788 			}
789 		}
790 		spin_unlock_irqrestore(&c->vc.lock, flags);
791 		ret = 0;
792 		break;
793 
794 	default:
795 		ret = -ENXIO;
796 		break;
797 	}
798 
799 	return ret;
800 }
801 
802 struct sa11x0_dma_channel_desc {
803 	u32 ddar;
804 	const char *name;
805 };
806 
807 #define CD(d1, d2) { .ddar = DDAR_##d1 | d2, .name = #d1 }
808 static const struct sa11x0_dma_channel_desc chan_desc[] = {
809 	CD(Ser0UDCTr, 0),
810 	CD(Ser0UDCRc, DDAR_RW),
811 	CD(Ser1SDLCTr, 0),
812 	CD(Ser1SDLCRc, DDAR_RW),
813 	CD(Ser1UARTTr, 0),
814 	CD(Ser1UARTRc, DDAR_RW),
815 	CD(Ser2ICPTr, 0),
816 	CD(Ser2ICPRc, DDAR_RW),
817 	CD(Ser3UARTTr, 0),
818 	CD(Ser3UARTRc, DDAR_RW),
819 	CD(Ser4MCP0Tr, 0),
820 	CD(Ser4MCP0Rc, DDAR_RW),
821 	CD(Ser4MCP1Tr, 0),
822 	CD(Ser4MCP1Rc, DDAR_RW),
823 	CD(Ser4SSPTr, 0),
824 	CD(Ser4SSPRc, DDAR_RW),
825 };
826 
827 static int sa11x0_dma_init_dmadev(struct dma_device *dmadev,
828 	struct device *dev)
829 {
830 	unsigned i;
831 
832 	dmadev->chancnt = ARRAY_SIZE(chan_desc);
833 	INIT_LIST_HEAD(&dmadev->channels);
834 	dmadev->dev = dev;
835 	dmadev->device_alloc_chan_resources = sa11x0_dma_alloc_chan_resources;
836 	dmadev->device_free_chan_resources = sa11x0_dma_free_chan_resources;
837 	dmadev->device_control = sa11x0_dma_control;
838 	dmadev->device_tx_status = sa11x0_dma_tx_status;
839 	dmadev->device_issue_pending = sa11x0_dma_issue_pending;
840 
841 	for (i = 0; i < dmadev->chancnt; i++) {
842 		struct sa11x0_dma_chan *c;
843 
844 		c = kzalloc(sizeof(*c), GFP_KERNEL);
845 		if (!c) {
846 			dev_err(dev, "no memory for channel %u\n", i);
847 			return -ENOMEM;
848 		}
849 
850 		c->status = DMA_IN_PROGRESS;
851 		c->ddar = chan_desc[i].ddar;
852 		c->name = chan_desc[i].name;
853 		INIT_LIST_HEAD(&c->node);
854 
855 		c->vc.desc_free = sa11x0_dma_free_desc;
856 		vchan_init(&c->vc, dmadev);
857 	}
858 
859 	return dma_async_device_register(dmadev);
860 }
861 
862 static int sa11x0_dma_request_irq(struct platform_device *pdev, int nr,
863 	void *data)
864 {
865 	int irq = platform_get_irq(pdev, nr);
866 
867 	if (irq <= 0)
868 		return -ENXIO;
869 
870 	return request_irq(irq, sa11x0_dma_irq, 0, dev_name(&pdev->dev), data);
871 }
872 
873 static void sa11x0_dma_free_irq(struct platform_device *pdev, int nr,
874 	void *data)
875 {
876 	int irq = platform_get_irq(pdev, nr);
877 	if (irq > 0)
878 		free_irq(irq, data);
879 }
880 
881 static void sa11x0_dma_free_channels(struct dma_device *dmadev)
882 {
883 	struct sa11x0_dma_chan *c, *cn;
884 
885 	list_for_each_entry_safe(c, cn, &dmadev->channels, vc.chan.device_node) {
886 		list_del(&c->vc.chan.device_node);
887 		tasklet_kill(&c->vc.task);
888 		kfree(c);
889 	}
890 }
891 
892 static int sa11x0_dma_probe(struct platform_device *pdev)
893 {
894 	struct sa11x0_dma_dev *d;
895 	struct resource *res;
896 	unsigned i;
897 	int ret;
898 
899 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
900 	if (!res)
901 		return -ENXIO;
902 
903 	d = kzalloc(sizeof(*d), GFP_KERNEL);
904 	if (!d) {
905 		ret = -ENOMEM;
906 		goto err_alloc;
907 	}
908 
909 	spin_lock_init(&d->lock);
910 	INIT_LIST_HEAD(&d->chan_pending);
911 
912 	d->base = ioremap(res->start, resource_size(res));
913 	if (!d->base) {
914 		ret = -ENOMEM;
915 		goto err_ioremap;
916 	}
917 
918 	tasklet_init(&d->task, sa11x0_dma_tasklet, (unsigned long)d);
919 
920 	for (i = 0; i < NR_PHY_CHAN; i++) {
921 		struct sa11x0_dma_phy *p = &d->phy[i];
922 
923 		p->dev = d;
924 		p->num = i;
925 		p->base = d->base + i * DMA_SIZE;
926 		writel_relaxed(DCSR_RUN | DCSR_IE | DCSR_ERROR |
927 			DCSR_DONEA | DCSR_STRTA | DCSR_DONEB | DCSR_STRTB,
928 			p->base + DMA_DCSR_C);
929 		writel_relaxed(0, p->base + DMA_DDAR);
930 
931 		ret = sa11x0_dma_request_irq(pdev, i, p);
932 		if (ret) {
933 			while (i) {
934 				i--;
935 				sa11x0_dma_free_irq(pdev, i, &d->phy[i]);
936 			}
937 			goto err_irq;
938 		}
939 	}
940 
941 	dma_cap_set(DMA_SLAVE, d->slave.cap_mask);
942 	dma_cap_set(DMA_CYCLIC, d->slave.cap_mask);
943 	d->slave.device_prep_slave_sg = sa11x0_dma_prep_slave_sg;
944 	d->slave.device_prep_dma_cyclic = sa11x0_dma_prep_dma_cyclic;
945 	ret = sa11x0_dma_init_dmadev(&d->slave, &pdev->dev);
946 	if (ret) {
947 		dev_warn(d->slave.dev, "failed to register slave async device: %d\n",
948 			ret);
949 		goto err_slave_reg;
950 	}
951 
952 	platform_set_drvdata(pdev, d);
953 	return 0;
954 
955  err_slave_reg:
956 	sa11x0_dma_free_channels(&d->slave);
957 	for (i = 0; i < NR_PHY_CHAN; i++)
958 		sa11x0_dma_free_irq(pdev, i, &d->phy[i]);
959  err_irq:
960 	tasklet_kill(&d->task);
961 	iounmap(d->base);
962  err_ioremap:
963 	kfree(d);
964  err_alloc:
965 	return ret;
966 }
967 
968 static int sa11x0_dma_remove(struct platform_device *pdev)
969 {
970 	struct sa11x0_dma_dev *d = platform_get_drvdata(pdev);
971 	unsigned pch;
972 
973 	dma_async_device_unregister(&d->slave);
974 
975 	sa11x0_dma_free_channels(&d->slave);
976 	for (pch = 0; pch < NR_PHY_CHAN; pch++)
977 		sa11x0_dma_free_irq(pdev, pch, &d->phy[pch]);
978 	tasklet_kill(&d->task);
979 	iounmap(d->base);
980 	kfree(d);
981 
982 	return 0;
983 }
984 
985 static int sa11x0_dma_suspend(struct device *dev)
986 {
987 	struct sa11x0_dma_dev *d = dev_get_drvdata(dev);
988 	unsigned pch;
989 
990 	for (pch = 0; pch < NR_PHY_CHAN; pch++) {
991 		struct sa11x0_dma_phy *p = &d->phy[pch];
992 		u32 dcsr, saved_dcsr;
993 
994 		dcsr = saved_dcsr = readl_relaxed(p->base + DMA_DCSR_R);
995 		if (dcsr & DCSR_RUN) {
996 			writel(DCSR_RUN | DCSR_IE, p->base + DMA_DCSR_C);
997 			dcsr = readl_relaxed(p->base + DMA_DCSR_R);
998 		}
999 
1000 		saved_dcsr &= DCSR_RUN | DCSR_IE;
1001 		if (dcsr & DCSR_BIU) {
1002 			p->dbs[0] = readl_relaxed(p->base + DMA_DBSB);
1003 			p->dbt[0] = readl_relaxed(p->base + DMA_DBTB);
1004 			p->dbs[1] = readl_relaxed(p->base + DMA_DBSA);
1005 			p->dbt[1] = readl_relaxed(p->base + DMA_DBTA);
1006 			saved_dcsr |= (dcsr & DCSR_STRTA ? DCSR_STRTB : 0) |
1007 				      (dcsr & DCSR_STRTB ? DCSR_STRTA : 0);
1008 		} else {
1009 			p->dbs[0] = readl_relaxed(p->base + DMA_DBSA);
1010 			p->dbt[0] = readl_relaxed(p->base + DMA_DBTA);
1011 			p->dbs[1] = readl_relaxed(p->base + DMA_DBSB);
1012 			p->dbt[1] = readl_relaxed(p->base + DMA_DBTB);
1013 			saved_dcsr |= dcsr & (DCSR_STRTA | DCSR_STRTB);
1014 		}
1015 		p->dcsr = saved_dcsr;
1016 
1017 		writel(DCSR_STRTA | DCSR_STRTB, p->base + DMA_DCSR_C);
1018 	}
1019 
1020 	return 0;
1021 }
1022 
1023 static int sa11x0_dma_resume(struct device *dev)
1024 {
1025 	struct sa11x0_dma_dev *d = dev_get_drvdata(dev);
1026 	unsigned pch;
1027 
1028 	for (pch = 0; pch < NR_PHY_CHAN; pch++) {
1029 		struct sa11x0_dma_phy *p = &d->phy[pch];
1030 		struct sa11x0_dma_desc *txd = NULL;
1031 		u32 dcsr = readl_relaxed(p->base + DMA_DCSR_R);
1032 
1033 		WARN_ON(dcsr & (DCSR_BIU | DCSR_STRTA | DCSR_STRTB | DCSR_RUN));
1034 
1035 		if (p->txd_done)
1036 			txd = p->txd_done;
1037 		else if (p->txd_load)
1038 			txd = p->txd_load;
1039 
1040 		if (!txd)
1041 			continue;
1042 
1043 		writel_relaxed(txd->ddar, p->base + DMA_DDAR);
1044 
1045 		writel_relaxed(p->dbs[0], p->base + DMA_DBSA);
1046 		writel_relaxed(p->dbt[0], p->base + DMA_DBTA);
1047 		writel_relaxed(p->dbs[1], p->base + DMA_DBSB);
1048 		writel_relaxed(p->dbt[1], p->base + DMA_DBTB);
1049 		writel_relaxed(p->dcsr, p->base + DMA_DCSR_S);
1050 	}
1051 
1052 	return 0;
1053 }
1054 
1055 static const struct dev_pm_ops sa11x0_dma_pm_ops = {
1056 	.suspend_noirq = sa11x0_dma_suspend,
1057 	.resume_noirq = sa11x0_dma_resume,
1058 	.freeze_noirq = sa11x0_dma_suspend,
1059 	.thaw_noirq = sa11x0_dma_resume,
1060 	.poweroff_noirq = sa11x0_dma_suspend,
1061 	.restore_noirq = sa11x0_dma_resume,
1062 };
1063 
1064 static struct platform_driver sa11x0_dma_driver = {
1065 	.driver = {
1066 		.name	= "sa11x0-dma",
1067 		.owner	= THIS_MODULE,
1068 		.pm	= &sa11x0_dma_pm_ops,
1069 	},
1070 	.probe		= sa11x0_dma_probe,
1071 	.remove		= sa11x0_dma_remove,
1072 };
1073 
1074 bool sa11x0_dma_filter_fn(struct dma_chan *chan, void *param)
1075 {
1076 	if (chan->device->dev->driver == &sa11x0_dma_driver.driver) {
1077 		struct sa11x0_dma_chan *c = to_sa11x0_dma_chan(chan);
1078 		const char *p = param;
1079 
1080 		return !strcmp(c->name, p);
1081 	}
1082 	return false;
1083 }
1084 EXPORT_SYMBOL(sa11x0_dma_filter_fn);
1085 
1086 static int __init sa11x0_dma_init(void)
1087 {
1088 	return platform_driver_register(&sa11x0_dma_driver);
1089 }
1090 subsys_initcall(sa11x0_dma_init);
1091 
1092 static void __exit sa11x0_dma_exit(void)
1093 {
1094 	platform_driver_unregister(&sa11x0_dma_driver);
1095 }
1096 module_exit(sa11x0_dma_exit);
1097 
1098 MODULE_AUTHOR("Russell King");
1099 MODULE_DESCRIPTION("SA-11x0 DMA driver");
1100 MODULE_LICENSE("GPL v2");
1101 MODULE_ALIAS("platform:sa11x0-dma");
1102