xref: /linux/drivers/dma/pch_dma.c (revision f7af616c632ee2ac3af0876fe33bf9e0232e665a)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Topcliff PCH DMA controller driver
4  * Copyright (c) 2010 Intel Corporation
5  * Copyright (C) 2011 LAPIS Semiconductor Co., Ltd.
6  */
7 
8 #include <linux/dmaengine.h>
9 #include <linux/dma-mapping.h>
10 #include <linux/init.h>
11 #include <linux/pci.h>
12 #include <linux/slab.h>
13 #include <linux/interrupt.h>
14 #include <linux/module.h>
15 #include <linux/pch_dma.h>
16 
17 #include "dmaengine.h"
18 
19 #define DRV_NAME "pch-dma"
20 
21 #define DMA_CTL0_DISABLE		0x0
22 #define DMA_CTL0_SG			0x1
23 #define DMA_CTL0_ONESHOT		0x2
24 #define DMA_CTL0_MODE_MASK_BITS		0x3
25 #define DMA_CTL0_DIR_SHIFT_BITS		2
26 #define DMA_CTL0_BITS_PER_CH		4
27 
28 #define DMA_CTL2_START_SHIFT_BITS	8
29 #define DMA_CTL2_IRQ_ENABLE_MASK	((1UL << DMA_CTL2_START_SHIFT_BITS) - 1)
30 
31 #define DMA_STATUS_IDLE			0x0
32 #define DMA_STATUS_DESC_READ		0x1
33 #define DMA_STATUS_WAIT			0x2
34 #define DMA_STATUS_ACCESS		0x3
35 #define DMA_STATUS_BITS_PER_CH		2
36 #define DMA_STATUS_MASK_BITS		0x3
37 #define DMA_STATUS_SHIFT_BITS		16
38 #define DMA_STATUS_IRQ(x)		(0x1 << (x))
39 #define DMA_STATUS0_ERR(x)		(0x1 << ((x) + 8))
40 #define DMA_STATUS2_ERR(x)		(0x1 << (x))
41 
42 #define DMA_DESC_WIDTH_SHIFT_BITS	12
43 #define DMA_DESC_WIDTH_1_BYTE		(0x3 << DMA_DESC_WIDTH_SHIFT_BITS)
44 #define DMA_DESC_WIDTH_2_BYTES		(0x2 << DMA_DESC_WIDTH_SHIFT_BITS)
45 #define DMA_DESC_WIDTH_4_BYTES		(0x0 << DMA_DESC_WIDTH_SHIFT_BITS)
46 #define DMA_DESC_MAX_COUNT_1_BYTE	0x3FF
47 #define DMA_DESC_MAX_COUNT_2_BYTES	0x3FF
48 #define DMA_DESC_MAX_COUNT_4_BYTES	0x7FF
49 #define DMA_DESC_END_WITHOUT_IRQ	0x0
50 #define DMA_DESC_END_WITH_IRQ		0x1
51 #define DMA_DESC_FOLLOW_WITHOUT_IRQ	0x2
52 #define DMA_DESC_FOLLOW_WITH_IRQ	0x3
53 
54 #define MAX_CHAN_NR			12
55 
56 #define DMA_MASK_CTL0_MODE	0x33333333
57 #define DMA_MASK_CTL2_MODE	0x00003333
58 
59 static unsigned int init_nr_desc_per_channel = 64;
60 module_param(init_nr_desc_per_channel, uint, 0644);
61 MODULE_PARM_DESC(init_nr_desc_per_channel,
62 		 "initial descriptors per channel (default: 64)");
63 
64 struct pch_dma_desc_regs {
65 	u32	dev_addr;
66 	u32	mem_addr;
67 	u32	size;
68 	u32	next;
69 };
70 
71 struct pch_dma_regs {
72 	u32	dma_ctl0;
73 	u32	dma_ctl1;
74 	u32	dma_ctl2;
75 	u32	dma_ctl3;
76 	u32	dma_sts0;
77 	u32	dma_sts1;
78 	u32	dma_sts2;
79 	u32	reserved3;
80 	struct pch_dma_desc_regs desc[MAX_CHAN_NR];
81 };
82 
83 struct pch_dma_desc {
84 	struct pch_dma_desc_regs regs;
85 	struct dma_async_tx_descriptor txd;
86 	struct list_head	desc_node;
87 	struct list_head	tx_list;
88 };
89 
90 struct pch_dma_chan {
91 	struct dma_chan		chan;
92 	void __iomem *membase;
93 	enum dma_transfer_direction dir;
94 	struct tasklet_struct	tasklet;
95 	unsigned long		err_status;
96 
97 	spinlock_t		lock;
98 
99 	struct list_head	active_list;
100 	struct list_head	queue;
101 	struct list_head	free_list;
102 	unsigned int		descs_allocated;
103 };
104 
105 #define PDC_DEV_ADDR	0x00
106 #define PDC_MEM_ADDR	0x04
107 #define PDC_SIZE	0x08
108 #define PDC_NEXT	0x0C
109 
110 #define channel_readl(pdc, name) \
111 	readl((pdc)->membase + PDC_##name)
112 #define channel_writel(pdc, name, val) \
113 	writel((val), (pdc)->membase + PDC_##name)
114 
115 struct pch_dma {
116 	struct dma_device	dma;
117 	void __iomem *membase;
118 	struct dma_pool		*pool;
119 	struct pch_dma_regs	regs;
120 	struct pch_dma_desc_regs ch_regs[MAX_CHAN_NR];
121 	struct pch_dma_chan	channels[MAX_CHAN_NR];
122 };
123 
124 #define PCH_DMA_CTL0	0x00
125 #define PCH_DMA_CTL1	0x04
126 #define PCH_DMA_CTL2	0x08
127 #define PCH_DMA_CTL3	0x0C
128 #define PCH_DMA_STS0	0x10
129 #define PCH_DMA_STS1	0x14
130 #define PCH_DMA_STS2	0x18
131 
132 #define dma_readl(pd, name) \
133 	readl((pd)->membase + PCH_DMA_##name)
134 #define dma_writel(pd, name, val) \
135 	writel((val), (pd)->membase + PCH_DMA_##name)
136 
137 static inline
138 struct pch_dma_desc *to_pd_desc(struct dma_async_tx_descriptor *txd)
139 {
140 	return container_of(txd, struct pch_dma_desc, txd);
141 }
142 
143 static inline struct pch_dma_chan *to_pd_chan(struct dma_chan *chan)
144 {
145 	return container_of(chan, struct pch_dma_chan, chan);
146 }
147 
148 static inline struct pch_dma *to_pd(struct dma_device *ddev)
149 {
150 	return container_of(ddev, struct pch_dma, dma);
151 }
152 
153 static inline struct device *chan2dev(struct dma_chan *chan)
154 {
155 	return &chan->dev->device;
156 }
157 
158 static inline struct device *chan2parent(struct dma_chan *chan)
159 {
160 	return chan->dev->device.parent;
161 }
162 
163 static inline
164 struct pch_dma_desc *pdc_first_active(struct pch_dma_chan *pd_chan)
165 {
166 	return list_first_entry(&pd_chan->active_list,
167 				struct pch_dma_desc, desc_node);
168 }
169 
170 static inline
171 struct pch_dma_desc *pdc_first_queued(struct pch_dma_chan *pd_chan)
172 {
173 	return list_first_entry(&pd_chan->queue,
174 				struct pch_dma_desc, desc_node);
175 }
176 
177 static void pdc_enable_irq(struct dma_chan *chan, int enable)
178 {
179 	struct pch_dma *pd = to_pd(chan->device);
180 	u32 val;
181 	int pos;
182 
183 	if (chan->chan_id < 8)
184 		pos = chan->chan_id;
185 	else
186 		pos = chan->chan_id + 8;
187 
188 	val = dma_readl(pd, CTL2);
189 
190 	if (enable)
191 		val |= 0x1 << pos;
192 	else
193 		val &= ~(0x1 << pos);
194 
195 	dma_writel(pd, CTL2, val);
196 
197 	dev_dbg(chan2dev(chan), "pdc_enable_irq: chan %d -> %x\n",
198 		chan->chan_id, val);
199 }
200 
201 static void pdc_set_dir(struct dma_chan *chan)
202 {
203 	struct pch_dma_chan *pd_chan = to_pd_chan(chan);
204 	struct pch_dma *pd = to_pd(chan->device);
205 	u32 val;
206 	u32 mask_mode;
207 	u32 mask_ctl;
208 
209 	if (chan->chan_id < 8) {
210 		val = dma_readl(pd, CTL0);
211 
212 		mask_mode = DMA_CTL0_MODE_MASK_BITS <<
213 					(DMA_CTL0_BITS_PER_CH * chan->chan_id);
214 		mask_ctl = DMA_MASK_CTL0_MODE & ~(DMA_CTL0_MODE_MASK_BITS <<
215 				       (DMA_CTL0_BITS_PER_CH * chan->chan_id));
216 		val &= mask_mode;
217 		if (pd_chan->dir == DMA_MEM_TO_DEV)
218 			val |= 0x1 << (DMA_CTL0_BITS_PER_CH * chan->chan_id +
219 				       DMA_CTL0_DIR_SHIFT_BITS);
220 		else
221 			val &= ~(0x1 << (DMA_CTL0_BITS_PER_CH * chan->chan_id +
222 					 DMA_CTL0_DIR_SHIFT_BITS));
223 
224 		val |= mask_ctl;
225 		dma_writel(pd, CTL0, val);
226 	} else {
227 		int ch = chan->chan_id - 8; /* ch8-->0 ch9-->1 ... ch11->3 */
228 		val = dma_readl(pd, CTL3);
229 
230 		mask_mode = DMA_CTL0_MODE_MASK_BITS <<
231 						(DMA_CTL0_BITS_PER_CH * ch);
232 		mask_ctl = DMA_MASK_CTL2_MODE & ~(DMA_CTL0_MODE_MASK_BITS <<
233 						 (DMA_CTL0_BITS_PER_CH * ch));
234 		val &= mask_mode;
235 		if (pd_chan->dir == DMA_MEM_TO_DEV)
236 			val |= 0x1 << (DMA_CTL0_BITS_PER_CH * ch +
237 				       DMA_CTL0_DIR_SHIFT_BITS);
238 		else
239 			val &= ~(0x1 << (DMA_CTL0_BITS_PER_CH * ch +
240 					 DMA_CTL0_DIR_SHIFT_BITS));
241 		val |= mask_ctl;
242 		dma_writel(pd, CTL3, val);
243 	}
244 
245 	dev_dbg(chan2dev(chan), "pdc_set_dir: chan %d -> %x\n",
246 		chan->chan_id, val);
247 }
248 
249 static void pdc_set_mode(struct dma_chan *chan, u32 mode)
250 {
251 	struct pch_dma *pd = to_pd(chan->device);
252 	u32 val;
253 	u32 mask_ctl;
254 	u32 mask_dir;
255 
256 	if (chan->chan_id < 8) {
257 		mask_ctl = DMA_MASK_CTL0_MODE & ~(DMA_CTL0_MODE_MASK_BITS <<
258 			   (DMA_CTL0_BITS_PER_CH * chan->chan_id));
259 		mask_dir = 1 << (DMA_CTL0_BITS_PER_CH * chan->chan_id +\
260 				 DMA_CTL0_DIR_SHIFT_BITS);
261 		val = dma_readl(pd, CTL0);
262 		val &= mask_dir;
263 		val |= mode << (DMA_CTL0_BITS_PER_CH * chan->chan_id);
264 		val |= mask_ctl;
265 		dma_writel(pd, CTL0, val);
266 	} else {
267 		int ch = chan->chan_id - 8; /* ch8-->0 ch9-->1 ... ch11->3 */
268 		mask_ctl = DMA_MASK_CTL2_MODE & ~(DMA_CTL0_MODE_MASK_BITS <<
269 						 (DMA_CTL0_BITS_PER_CH * ch));
270 		mask_dir = 1 << (DMA_CTL0_BITS_PER_CH * ch +\
271 				 DMA_CTL0_DIR_SHIFT_BITS);
272 		val = dma_readl(pd, CTL3);
273 		val &= mask_dir;
274 		val |= mode << (DMA_CTL0_BITS_PER_CH * ch);
275 		val |= mask_ctl;
276 		dma_writel(pd, CTL3, val);
277 	}
278 
279 	dev_dbg(chan2dev(chan), "pdc_set_mode: chan %d -> %x\n",
280 		chan->chan_id, val);
281 }
282 
283 static u32 pdc_get_status0(struct pch_dma_chan *pd_chan)
284 {
285 	struct pch_dma *pd = to_pd(pd_chan->chan.device);
286 	u32 val;
287 
288 	val = dma_readl(pd, STS0);
289 	return DMA_STATUS_MASK_BITS & (val >> (DMA_STATUS_SHIFT_BITS +
290 			DMA_STATUS_BITS_PER_CH * pd_chan->chan.chan_id));
291 }
292 
293 static u32 pdc_get_status2(struct pch_dma_chan *pd_chan)
294 {
295 	struct pch_dma *pd = to_pd(pd_chan->chan.device);
296 	u32 val;
297 
298 	val = dma_readl(pd, STS2);
299 	return DMA_STATUS_MASK_BITS & (val >> (DMA_STATUS_SHIFT_BITS +
300 			DMA_STATUS_BITS_PER_CH * (pd_chan->chan.chan_id - 8)));
301 }
302 
303 static bool pdc_is_idle(struct pch_dma_chan *pd_chan)
304 {
305 	u32 sts;
306 
307 	if (pd_chan->chan.chan_id < 8)
308 		sts = pdc_get_status0(pd_chan);
309 	else
310 		sts = pdc_get_status2(pd_chan);
311 
312 
313 	if (sts == DMA_STATUS_IDLE)
314 		return true;
315 	else
316 		return false;
317 }
318 
319 static void pdc_dostart(struct pch_dma_chan *pd_chan, struct pch_dma_desc* desc)
320 {
321 	if (!pdc_is_idle(pd_chan)) {
322 		dev_err(chan2dev(&pd_chan->chan),
323 			"BUG: Attempt to start non-idle channel\n");
324 		return;
325 	}
326 
327 	dev_dbg(chan2dev(&pd_chan->chan), "chan %d -> dev_addr: %x\n",
328 		pd_chan->chan.chan_id, desc->regs.dev_addr);
329 	dev_dbg(chan2dev(&pd_chan->chan), "chan %d -> mem_addr: %x\n",
330 		pd_chan->chan.chan_id, desc->regs.mem_addr);
331 	dev_dbg(chan2dev(&pd_chan->chan), "chan %d -> size: %x\n",
332 		pd_chan->chan.chan_id, desc->regs.size);
333 	dev_dbg(chan2dev(&pd_chan->chan), "chan %d -> next: %x\n",
334 		pd_chan->chan.chan_id, desc->regs.next);
335 
336 	if (list_empty(&desc->tx_list)) {
337 		channel_writel(pd_chan, DEV_ADDR, desc->regs.dev_addr);
338 		channel_writel(pd_chan, MEM_ADDR, desc->regs.mem_addr);
339 		channel_writel(pd_chan, SIZE, desc->regs.size);
340 		channel_writel(pd_chan, NEXT, desc->regs.next);
341 		pdc_set_mode(&pd_chan->chan, DMA_CTL0_ONESHOT);
342 	} else {
343 		channel_writel(pd_chan, NEXT, desc->txd.phys);
344 		pdc_set_mode(&pd_chan->chan, DMA_CTL0_SG);
345 	}
346 }
347 
348 static void pdc_chain_complete(struct pch_dma_chan *pd_chan,
349 			       struct pch_dma_desc *desc)
350 {
351 	struct dma_async_tx_descriptor *txd = &desc->txd;
352 	struct dmaengine_desc_callback cb;
353 
354 	dmaengine_desc_get_callback(txd, &cb);
355 	list_splice_init(&desc->tx_list, &pd_chan->free_list);
356 	list_move(&desc->desc_node, &pd_chan->free_list);
357 
358 	dmaengine_desc_callback_invoke(&cb, NULL);
359 }
360 
361 static void pdc_complete_all(struct pch_dma_chan *pd_chan)
362 {
363 	struct pch_dma_desc *desc, *_d;
364 	LIST_HEAD(list);
365 
366 	BUG_ON(!pdc_is_idle(pd_chan));
367 
368 	if (!list_empty(&pd_chan->queue))
369 		pdc_dostart(pd_chan, pdc_first_queued(pd_chan));
370 
371 	list_splice_init(&pd_chan->active_list, &list);
372 	list_splice_init(&pd_chan->queue, &pd_chan->active_list);
373 
374 	list_for_each_entry_safe(desc, _d, &list, desc_node)
375 		pdc_chain_complete(pd_chan, desc);
376 }
377 
378 static void pdc_handle_error(struct pch_dma_chan *pd_chan)
379 {
380 	struct pch_dma_desc *bad_desc;
381 
382 	bad_desc = pdc_first_active(pd_chan);
383 	list_del(&bad_desc->desc_node);
384 
385 	list_splice_init(&pd_chan->queue, pd_chan->active_list.prev);
386 
387 	if (!list_empty(&pd_chan->active_list))
388 		pdc_dostart(pd_chan, pdc_first_active(pd_chan));
389 
390 	dev_crit(chan2dev(&pd_chan->chan), "Bad descriptor submitted\n");
391 	dev_crit(chan2dev(&pd_chan->chan), "descriptor cookie: %d\n",
392 		 bad_desc->txd.cookie);
393 
394 	pdc_chain_complete(pd_chan, bad_desc);
395 }
396 
397 static void pdc_advance_work(struct pch_dma_chan *pd_chan)
398 {
399 	if (list_empty(&pd_chan->active_list) ||
400 		list_is_singular(&pd_chan->active_list)) {
401 		pdc_complete_all(pd_chan);
402 	} else {
403 		pdc_chain_complete(pd_chan, pdc_first_active(pd_chan));
404 		pdc_dostart(pd_chan, pdc_first_active(pd_chan));
405 	}
406 }
407 
408 static dma_cookie_t pd_tx_submit(struct dma_async_tx_descriptor *txd)
409 {
410 	struct pch_dma_desc *desc = to_pd_desc(txd);
411 	struct pch_dma_chan *pd_chan = to_pd_chan(txd->chan);
412 
413 	spin_lock(&pd_chan->lock);
414 
415 	if (list_empty(&pd_chan->active_list)) {
416 		list_add_tail(&desc->desc_node, &pd_chan->active_list);
417 		pdc_dostart(pd_chan, desc);
418 	} else {
419 		list_add_tail(&desc->desc_node, &pd_chan->queue);
420 	}
421 
422 	spin_unlock(&pd_chan->lock);
423 	return 0;
424 }
425 
426 static struct pch_dma_desc *pdc_alloc_desc(struct dma_chan *chan, gfp_t flags)
427 {
428 	struct pch_dma_desc *desc = NULL;
429 	struct pch_dma *pd = to_pd(chan->device);
430 	dma_addr_t addr;
431 
432 	desc = dma_pool_zalloc(pd->pool, flags, &addr);
433 	if (desc) {
434 		INIT_LIST_HEAD(&desc->tx_list);
435 		dma_async_tx_descriptor_init(&desc->txd, chan);
436 		desc->txd.tx_submit = pd_tx_submit;
437 		desc->txd.flags = DMA_CTRL_ACK;
438 		desc->txd.phys = addr;
439 	}
440 
441 	return desc;
442 }
443 
444 static struct pch_dma_desc *pdc_desc_get(struct pch_dma_chan *pd_chan)
445 {
446 	struct pch_dma_desc *desc, *_d;
447 	struct pch_dma_desc *ret = NULL;
448 	int i = 0;
449 
450 	spin_lock(&pd_chan->lock);
451 	list_for_each_entry_safe(desc, _d, &pd_chan->free_list, desc_node) {
452 		i++;
453 		if (async_tx_test_ack(&desc->txd)) {
454 			list_del(&desc->desc_node);
455 			ret = desc;
456 			break;
457 		}
458 		dev_dbg(chan2dev(&pd_chan->chan), "desc %p not ACKed\n", desc);
459 	}
460 	spin_unlock(&pd_chan->lock);
461 	dev_dbg(chan2dev(&pd_chan->chan), "scanned %d descriptors\n", i);
462 
463 	if (!ret) {
464 		ret = pdc_alloc_desc(&pd_chan->chan, GFP_ATOMIC);
465 		if (ret) {
466 			spin_lock(&pd_chan->lock);
467 			pd_chan->descs_allocated++;
468 			spin_unlock(&pd_chan->lock);
469 		} else {
470 			dev_err(chan2dev(&pd_chan->chan),
471 				"failed to alloc desc\n");
472 		}
473 	}
474 
475 	return ret;
476 }
477 
478 static void pdc_desc_put(struct pch_dma_chan *pd_chan,
479 			 struct pch_dma_desc *desc)
480 {
481 	if (desc) {
482 		spin_lock(&pd_chan->lock);
483 		list_splice_init(&desc->tx_list, &pd_chan->free_list);
484 		list_add(&desc->desc_node, &pd_chan->free_list);
485 		spin_unlock(&pd_chan->lock);
486 	}
487 }
488 
489 static int pd_alloc_chan_resources(struct dma_chan *chan)
490 {
491 	struct pch_dma_chan *pd_chan = to_pd_chan(chan);
492 	struct pch_dma_desc *desc;
493 	LIST_HEAD(tmp_list);
494 	int i;
495 
496 	if (!pdc_is_idle(pd_chan)) {
497 		dev_dbg(chan2dev(chan), "DMA channel not idle ?\n");
498 		return -EIO;
499 	}
500 
501 	if (!list_empty(&pd_chan->free_list))
502 		return pd_chan->descs_allocated;
503 
504 	for (i = 0; i < init_nr_desc_per_channel; i++) {
505 		desc = pdc_alloc_desc(chan, GFP_KERNEL);
506 
507 		if (!desc) {
508 			dev_warn(chan2dev(chan),
509 				"Only allocated %d initial descriptors\n", i);
510 			break;
511 		}
512 
513 		list_add_tail(&desc->desc_node, &tmp_list);
514 	}
515 
516 	spin_lock_irq(&pd_chan->lock);
517 	list_splice(&tmp_list, &pd_chan->free_list);
518 	pd_chan->descs_allocated = i;
519 	dma_cookie_init(chan);
520 	spin_unlock_irq(&pd_chan->lock);
521 
522 	pdc_enable_irq(chan, 1);
523 
524 	return pd_chan->descs_allocated;
525 }
526 
527 static void pd_free_chan_resources(struct dma_chan *chan)
528 {
529 	struct pch_dma_chan *pd_chan = to_pd_chan(chan);
530 	struct pch_dma *pd = to_pd(chan->device);
531 	struct pch_dma_desc *desc, *_d;
532 	LIST_HEAD(tmp_list);
533 
534 	BUG_ON(!pdc_is_idle(pd_chan));
535 	BUG_ON(!list_empty(&pd_chan->active_list));
536 	BUG_ON(!list_empty(&pd_chan->queue));
537 
538 	spin_lock_irq(&pd_chan->lock);
539 	list_splice_init(&pd_chan->free_list, &tmp_list);
540 	pd_chan->descs_allocated = 0;
541 	spin_unlock_irq(&pd_chan->lock);
542 
543 	list_for_each_entry_safe(desc, _d, &tmp_list, desc_node)
544 		dma_pool_free(pd->pool, desc, desc->txd.phys);
545 
546 	pdc_enable_irq(chan, 0);
547 }
548 
549 static enum dma_status pd_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
550 				    struct dma_tx_state *txstate)
551 {
552 	return dma_cookie_status(chan, cookie, txstate);
553 }
554 
555 static void pd_issue_pending(struct dma_chan *chan)
556 {
557 	struct pch_dma_chan *pd_chan = to_pd_chan(chan);
558 
559 	if (pdc_is_idle(pd_chan)) {
560 		spin_lock(&pd_chan->lock);
561 		pdc_advance_work(pd_chan);
562 		spin_unlock(&pd_chan->lock);
563 	}
564 }
565 
566 static struct dma_async_tx_descriptor *pd_prep_slave_sg(struct dma_chan *chan,
567 			struct scatterlist *sgl, unsigned int sg_len,
568 			enum dma_transfer_direction direction, unsigned long flags,
569 			void *context)
570 {
571 	struct pch_dma_chan *pd_chan = to_pd_chan(chan);
572 	struct pch_dma_slave *pd_slave = chan->private;
573 	struct pch_dma_desc *first = NULL;
574 	struct pch_dma_desc *prev = NULL;
575 	struct pch_dma_desc *desc = NULL;
576 	struct scatterlist *sg;
577 	dma_addr_t reg;
578 	int i;
579 
580 	if (unlikely(!sg_len)) {
581 		dev_info(chan2dev(chan), "prep_slave_sg: length is zero!\n");
582 		return NULL;
583 	}
584 
585 	if (direction == DMA_DEV_TO_MEM)
586 		reg = pd_slave->rx_reg;
587 	else if (direction == DMA_MEM_TO_DEV)
588 		reg = pd_slave->tx_reg;
589 	else
590 		return NULL;
591 
592 	pd_chan->dir = direction;
593 	pdc_set_dir(chan);
594 
595 	for_each_sg(sgl, sg, sg_len, i) {
596 		desc = pdc_desc_get(pd_chan);
597 
598 		if (!desc)
599 			goto err_desc_get;
600 
601 		desc->regs.dev_addr = reg;
602 		desc->regs.mem_addr = sg_dma_address(sg);
603 		desc->regs.size = sg_dma_len(sg);
604 		desc->regs.next = DMA_DESC_FOLLOW_WITHOUT_IRQ;
605 
606 		switch (pd_slave->width) {
607 		case PCH_DMA_WIDTH_1_BYTE:
608 			if (desc->regs.size > DMA_DESC_MAX_COUNT_1_BYTE)
609 				goto err_desc_get;
610 			desc->regs.size |= DMA_DESC_WIDTH_1_BYTE;
611 			break;
612 		case PCH_DMA_WIDTH_2_BYTES:
613 			if (desc->regs.size > DMA_DESC_MAX_COUNT_2_BYTES)
614 				goto err_desc_get;
615 			desc->regs.size |= DMA_DESC_WIDTH_2_BYTES;
616 			break;
617 		case PCH_DMA_WIDTH_4_BYTES:
618 			if (desc->regs.size > DMA_DESC_MAX_COUNT_4_BYTES)
619 				goto err_desc_get;
620 			desc->regs.size |= DMA_DESC_WIDTH_4_BYTES;
621 			break;
622 		default:
623 			goto err_desc_get;
624 		}
625 
626 		if (!first) {
627 			first = desc;
628 		} else {
629 			prev->regs.next |= desc->txd.phys;
630 			list_add_tail(&desc->desc_node, &first->tx_list);
631 		}
632 
633 		prev = desc;
634 	}
635 
636 	if (flags & DMA_PREP_INTERRUPT)
637 		desc->regs.next = DMA_DESC_END_WITH_IRQ;
638 	else
639 		desc->regs.next = DMA_DESC_END_WITHOUT_IRQ;
640 
641 	first->txd.cookie = -EBUSY;
642 	desc->txd.flags = flags;
643 
644 	return &first->txd;
645 
646 err_desc_get:
647 	dev_err(chan2dev(chan), "failed to get desc or wrong parameters\n");
648 	pdc_desc_put(pd_chan, first);
649 	return NULL;
650 }
651 
652 static int pd_device_terminate_all(struct dma_chan *chan)
653 {
654 	struct pch_dma_chan *pd_chan = to_pd_chan(chan);
655 	struct pch_dma_desc *desc, *_d;
656 	LIST_HEAD(list);
657 
658 	spin_lock_irq(&pd_chan->lock);
659 
660 	pdc_set_mode(&pd_chan->chan, DMA_CTL0_DISABLE);
661 
662 	list_splice_init(&pd_chan->active_list, &list);
663 	list_splice_init(&pd_chan->queue, &list);
664 
665 	list_for_each_entry_safe(desc, _d, &list, desc_node)
666 		pdc_chain_complete(pd_chan, desc);
667 
668 	spin_unlock_irq(&pd_chan->lock);
669 
670 	return 0;
671 }
672 
673 static void pdc_tasklet(struct tasklet_struct *t)
674 {
675 	struct pch_dma_chan *pd_chan = from_tasklet(pd_chan, t, tasklet);
676 	unsigned long flags;
677 
678 	if (!pdc_is_idle(pd_chan)) {
679 		dev_err(chan2dev(&pd_chan->chan),
680 			"BUG: handle non-idle channel in tasklet\n");
681 		return;
682 	}
683 
684 	spin_lock_irqsave(&pd_chan->lock, flags);
685 	if (test_and_clear_bit(0, &pd_chan->err_status))
686 		pdc_handle_error(pd_chan);
687 	else
688 		pdc_advance_work(pd_chan);
689 	spin_unlock_irqrestore(&pd_chan->lock, flags);
690 }
691 
692 static irqreturn_t pd_irq(int irq, void *devid)
693 {
694 	struct pch_dma *pd = (struct pch_dma *)devid;
695 	struct pch_dma_chan *pd_chan;
696 	u32 sts0;
697 	u32 sts2;
698 	int i;
699 	int ret0 = IRQ_NONE;
700 	int ret2 = IRQ_NONE;
701 
702 	sts0 = dma_readl(pd, STS0);
703 	sts2 = dma_readl(pd, STS2);
704 
705 	dev_dbg(pd->dma.dev, "pd_irq sts0: %x\n", sts0);
706 
707 	for (i = 0; i < pd->dma.chancnt; i++) {
708 		pd_chan = &pd->channels[i];
709 
710 		if (i < 8) {
711 			if (sts0 & DMA_STATUS_IRQ(i)) {
712 				if (sts0 & DMA_STATUS0_ERR(i))
713 					set_bit(0, &pd_chan->err_status);
714 
715 				tasklet_schedule(&pd_chan->tasklet);
716 				ret0 = IRQ_HANDLED;
717 			}
718 		} else {
719 			if (sts2 & DMA_STATUS_IRQ(i - 8)) {
720 				if (sts2 & DMA_STATUS2_ERR(i))
721 					set_bit(0, &pd_chan->err_status);
722 
723 				tasklet_schedule(&pd_chan->tasklet);
724 				ret2 = IRQ_HANDLED;
725 			}
726 		}
727 	}
728 
729 	/* clear interrupt bits in status register */
730 	if (ret0)
731 		dma_writel(pd, STS0, sts0);
732 	if (ret2)
733 		dma_writel(pd, STS2, sts2);
734 
735 	return ret0 | ret2;
736 }
737 
738 static void __maybe_unused pch_dma_save_regs(struct pch_dma *pd)
739 {
740 	struct pch_dma_chan *pd_chan;
741 	struct dma_chan *chan, *_c;
742 	int i = 0;
743 
744 	pd->regs.dma_ctl0 = dma_readl(pd, CTL0);
745 	pd->regs.dma_ctl1 = dma_readl(pd, CTL1);
746 	pd->regs.dma_ctl2 = dma_readl(pd, CTL2);
747 	pd->regs.dma_ctl3 = dma_readl(pd, CTL3);
748 
749 	list_for_each_entry_safe(chan, _c, &pd->dma.channels, device_node) {
750 		pd_chan = to_pd_chan(chan);
751 
752 		pd->ch_regs[i].dev_addr = channel_readl(pd_chan, DEV_ADDR);
753 		pd->ch_regs[i].mem_addr = channel_readl(pd_chan, MEM_ADDR);
754 		pd->ch_regs[i].size = channel_readl(pd_chan, SIZE);
755 		pd->ch_regs[i].next = channel_readl(pd_chan, NEXT);
756 
757 		i++;
758 	}
759 }
760 
761 static void __maybe_unused pch_dma_restore_regs(struct pch_dma *pd)
762 {
763 	struct pch_dma_chan *pd_chan;
764 	struct dma_chan *chan, *_c;
765 	int i = 0;
766 
767 	dma_writel(pd, CTL0, pd->regs.dma_ctl0);
768 	dma_writel(pd, CTL1, pd->regs.dma_ctl1);
769 	dma_writel(pd, CTL2, pd->regs.dma_ctl2);
770 	dma_writel(pd, CTL3, pd->regs.dma_ctl3);
771 
772 	list_for_each_entry_safe(chan, _c, &pd->dma.channels, device_node) {
773 		pd_chan = to_pd_chan(chan);
774 
775 		channel_writel(pd_chan, DEV_ADDR, pd->ch_regs[i].dev_addr);
776 		channel_writel(pd_chan, MEM_ADDR, pd->ch_regs[i].mem_addr);
777 		channel_writel(pd_chan, SIZE, pd->ch_regs[i].size);
778 		channel_writel(pd_chan, NEXT, pd->ch_regs[i].next);
779 
780 		i++;
781 	}
782 }
783 
784 static int __maybe_unused pch_dma_suspend(struct device *dev)
785 {
786 	struct pch_dma *pd = dev_get_drvdata(dev);
787 
788 	if (pd)
789 		pch_dma_save_regs(pd);
790 
791 	return 0;
792 }
793 
794 static int __maybe_unused pch_dma_resume(struct device *dev)
795 {
796 	struct pch_dma *pd = dev_get_drvdata(dev);
797 
798 	if (pd)
799 		pch_dma_restore_regs(pd);
800 
801 	return 0;
802 }
803 
804 static int pch_dma_probe(struct pci_dev *pdev,
805 				   const struct pci_device_id *id)
806 {
807 	struct pch_dma *pd;
808 	struct pch_dma_regs *regs;
809 	unsigned int nr_channels;
810 	int err;
811 	int i;
812 
813 	nr_channels = id->driver_data;
814 	pd = kzalloc(sizeof(*pd), GFP_KERNEL);
815 	if (!pd)
816 		return -ENOMEM;
817 
818 	pci_set_drvdata(pdev, pd);
819 
820 	err = pci_enable_device(pdev);
821 	if (err) {
822 		dev_err(&pdev->dev, "Cannot enable PCI device\n");
823 		goto err_free_mem;
824 	}
825 
826 	if (!(pci_resource_flags(pdev, 1) & IORESOURCE_MEM)) {
827 		dev_err(&pdev->dev, "Cannot find proper base address\n");
828 		err = -ENODEV;
829 		goto err_disable_pdev;
830 	}
831 
832 	err = pci_request_regions(pdev, DRV_NAME);
833 	if (err) {
834 		dev_err(&pdev->dev, "Cannot obtain PCI resources\n");
835 		goto err_disable_pdev;
836 	}
837 
838 	err = pci_set_dma_mask(pdev, DMA_BIT_MASK(32));
839 	if (err) {
840 		dev_err(&pdev->dev, "Cannot set proper DMA config\n");
841 		goto err_free_res;
842 	}
843 
844 	regs = pd->membase = pci_iomap(pdev, 1, 0);
845 	if (!pd->membase) {
846 		dev_err(&pdev->dev, "Cannot map MMIO registers\n");
847 		err = -ENOMEM;
848 		goto err_free_res;
849 	}
850 
851 	pci_set_master(pdev);
852 	pd->dma.dev = &pdev->dev;
853 
854 	err = request_irq(pdev->irq, pd_irq, IRQF_SHARED, DRV_NAME, pd);
855 	if (err) {
856 		dev_err(&pdev->dev, "Failed to request IRQ\n");
857 		goto err_iounmap;
858 	}
859 
860 	pd->pool = dma_pool_create("pch_dma_desc_pool", &pdev->dev,
861 				   sizeof(struct pch_dma_desc), 4, 0);
862 	if (!pd->pool) {
863 		dev_err(&pdev->dev, "Failed to alloc DMA descriptors\n");
864 		err = -ENOMEM;
865 		goto err_free_irq;
866 	}
867 
868 
869 	INIT_LIST_HEAD(&pd->dma.channels);
870 
871 	for (i = 0; i < nr_channels; i++) {
872 		struct pch_dma_chan *pd_chan = &pd->channels[i];
873 
874 		pd_chan->chan.device = &pd->dma;
875 		dma_cookie_init(&pd_chan->chan);
876 
877 		pd_chan->membase = &regs->desc[i];
878 
879 		spin_lock_init(&pd_chan->lock);
880 
881 		INIT_LIST_HEAD(&pd_chan->active_list);
882 		INIT_LIST_HEAD(&pd_chan->queue);
883 		INIT_LIST_HEAD(&pd_chan->free_list);
884 
885 		tasklet_setup(&pd_chan->tasklet, pdc_tasklet);
886 		list_add_tail(&pd_chan->chan.device_node, &pd->dma.channels);
887 	}
888 
889 	dma_cap_zero(pd->dma.cap_mask);
890 	dma_cap_set(DMA_PRIVATE, pd->dma.cap_mask);
891 	dma_cap_set(DMA_SLAVE, pd->dma.cap_mask);
892 
893 	pd->dma.device_alloc_chan_resources = pd_alloc_chan_resources;
894 	pd->dma.device_free_chan_resources = pd_free_chan_resources;
895 	pd->dma.device_tx_status = pd_tx_status;
896 	pd->dma.device_issue_pending = pd_issue_pending;
897 	pd->dma.device_prep_slave_sg = pd_prep_slave_sg;
898 	pd->dma.device_terminate_all = pd_device_terminate_all;
899 
900 	err = dma_async_device_register(&pd->dma);
901 	if (err) {
902 		dev_err(&pdev->dev, "Failed to register DMA device\n");
903 		goto err_free_pool;
904 	}
905 
906 	return 0;
907 
908 err_free_pool:
909 	dma_pool_destroy(pd->pool);
910 err_free_irq:
911 	free_irq(pdev->irq, pd);
912 err_iounmap:
913 	pci_iounmap(pdev, pd->membase);
914 err_free_res:
915 	pci_release_regions(pdev);
916 err_disable_pdev:
917 	pci_disable_device(pdev);
918 err_free_mem:
919 	kfree(pd);
920 	return err;
921 }
922 
923 static void pch_dma_remove(struct pci_dev *pdev)
924 {
925 	struct pch_dma *pd = pci_get_drvdata(pdev);
926 	struct pch_dma_chan *pd_chan;
927 	struct dma_chan *chan, *_c;
928 
929 	if (pd) {
930 		dma_async_device_unregister(&pd->dma);
931 
932 		free_irq(pdev->irq, pd);
933 
934 		list_for_each_entry_safe(chan, _c, &pd->dma.channels,
935 					 device_node) {
936 			pd_chan = to_pd_chan(chan);
937 
938 			tasklet_kill(&pd_chan->tasklet);
939 		}
940 
941 		dma_pool_destroy(pd->pool);
942 		pci_iounmap(pdev, pd->membase);
943 		pci_release_regions(pdev);
944 		pci_disable_device(pdev);
945 		kfree(pd);
946 	}
947 }
948 
949 /* PCI Device ID of DMA device */
950 #define PCI_DEVICE_ID_EG20T_PCH_DMA_8CH        0x8810
951 #define PCI_DEVICE_ID_EG20T_PCH_DMA_4CH        0x8815
952 #define PCI_DEVICE_ID_ML7213_DMA1_8CH	0x8026
953 #define PCI_DEVICE_ID_ML7213_DMA2_8CH	0x802B
954 #define PCI_DEVICE_ID_ML7213_DMA3_4CH	0x8034
955 #define PCI_DEVICE_ID_ML7213_DMA4_12CH	0x8032
956 #define PCI_DEVICE_ID_ML7223_DMA1_4CH	0x800B
957 #define PCI_DEVICE_ID_ML7223_DMA2_4CH	0x800E
958 #define PCI_DEVICE_ID_ML7223_DMA3_4CH	0x8017
959 #define PCI_DEVICE_ID_ML7223_DMA4_4CH	0x803B
960 #define PCI_DEVICE_ID_ML7831_DMA1_8CH	0x8810
961 #define PCI_DEVICE_ID_ML7831_DMA2_4CH	0x8815
962 
963 static const struct pci_device_id pch_dma_id_table[] = {
964 	{ PCI_VDEVICE(INTEL, PCI_DEVICE_ID_EG20T_PCH_DMA_8CH), 8 },
965 	{ PCI_VDEVICE(INTEL, PCI_DEVICE_ID_EG20T_PCH_DMA_4CH), 4 },
966 	{ PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7213_DMA1_8CH), 8}, /* UART Video */
967 	{ PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7213_DMA2_8CH), 8}, /* PCMIF SPI */
968 	{ PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7213_DMA3_4CH), 4}, /* FPGA */
969 	{ PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7213_DMA4_12CH), 12}, /* I2S */
970 	{ PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7223_DMA1_4CH), 4}, /* UART */
971 	{ PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7223_DMA2_4CH), 4}, /* Video SPI */
972 	{ PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7223_DMA3_4CH), 4}, /* Security */
973 	{ PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7223_DMA4_4CH), 4}, /* FPGA */
974 	{ PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7831_DMA1_8CH), 8}, /* UART */
975 	{ PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7831_DMA2_4CH), 4}, /* SPI */
976 	{ 0, },
977 };
978 
979 static SIMPLE_DEV_PM_OPS(pch_dma_pm_ops, pch_dma_suspend, pch_dma_resume);
980 
981 static struct pci_driver pch_dma_driver = {
982 	.name		= DRV_NAME,
983 	.id_table	= pch_dma_id_table,
984 	.probe		= pch_dma_probe,
985 	.remove		= pch_dma_remove,
986 	.driver.pm	= &pch_dma_pm_ops,
987 };
988 
989 module_pci_driver(pch_dma_driver);
990 
991 MODULE_DESCRIPTION("Intel EG20T PCH / LAPIS Semicon ML7213/ML7223/ML7831 IOH "
992 		   "DMA controller driver");
993 MODULE_AUTHOR("Yong Wang <yong.y.wang@intel.com>");
994 MODULE_LICENSE("GPL v2");
995 MODULE_DEVICE_TABLE(pci, pch_dma_id_table);
996