xref: /openbmc/linux/drivers/dma/pch_dma.c (revision 6d99a79c)
1 /*
2  * Topcliff PCH DMA controller driver
3  * Copyright (c) 2010 Intel Corporation
4  * Copyright (C) 2011 LAPIS Semiconductor Co., Ltd.
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 as
8  * published by the Free Software Foundation.
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13  * GNU General Public License for more details.
14  */
15 
16 #include <linux/dmaengine.h>
17 #include <linux/dma-mapping.h>
18 #include <linux/init.h>
19 #include <linux/pci.h>
20 #include <linux/slab.h>
21 #include <linux/interrupt.h>
22 #include <linux/module.h>
23 #include <linux/pch_dma.h>
24 
25 #include "dmaengine.h"
26 
27 #define DRV_NAME "pch-dma"
28 
29 #define DMA_CTL0_DISABLE		0x0
30 #define DMA_CTL0_SG			0x1
31 #define DMA_CTL0_ONESHOT		0x2
32 #define DMA_CTL0_MODE_MASK_BITS		0x3
33 #define DMA_CTL0_DIR_SHIFT_BITS		2
34 #define DMA_CTL0_BITS_PER_CH		4
35 
36 #define DMA_CTL2_START_SHIFT_BITS	8
37 #define DMA_CTL2_IRQ_ENABLE_MASK	((1UL << DMA_CTL2_START_SHIFT_BITS) - 1)
38 
39 #define DMA_STATUS_IDLE			0x0
40 #define DMA_STATUS_DESC_READ		0x1
41 #define DMA_STATUS_WAIT			0x2
42 #define DMA_STATUS_ACCESS		0x3
43 #define DMA_STATUS_BITS_PER_CH		2
44 #define DMA_STATUS_MASK_BITS		0x3
45 #define DMA_STATUS_SHIFT_BITS		16
46 #define DMA_STATUS_IRQ(x)		(0x1 << (x))
47 #define DMA_STATUS0_ERR(x)		(0x1 << ((x) + 8))
48 #define DMA_STATUS2_ERR(x)		(0x1 << (x))
49 
50 #define DMA_DESC_WIDTH_SHIFT_BITS	12
51 #define DMA_DESC_WIDTH_1_BYTE		(0x3 << DMA_DESC_WIDTH_SHIFT_BITS)
52 #define DMA_DESC_WIDTH_2_BYTES		(0x2 << DMA_DESC_WIDTH_SHIFT_BITS)
53 #define DMA_DESC_WIDTH_4_BYTES		(0x0 << DMA_DESC_WIDTH_SHIFT_BITS)
54 #define DMA_DESC_MAX_COUNT_1_BYTE	0x3FF
55 #define DMA_DESC_MAX_COUNT_2_BYTES	0x3FF
56 #define DMA_DESC_MAX_COUNT_4_BYTES	0x7FF
57 #define DMA_DESC_END_WITHOUT_IRQ	0x0
58 #define DMA_DESC_END_WITH_IRQ		0x1
59 #define DMA_DESC_FOLLOW_WITHOUT_IRQ	0x2
60 #define DMA_DESC_FOLLOW_WITH_IRQ	0x3
61 
62 #define MAX_CHAN_NR			12
63 
64 #define DMA_MASK_CTL0_MODE	0x33333333
65 #define DMA_MASK_CTL2_MODE	0x00003333
66 
67 static unsigned int init_nr_desc_per_channel = 64;
68 module_param(init_nr_desc_per_channel, uint, 0644);
69 MODULE_PARM_DESC(init_nr_desc_per_channel,
70 		 "initial descriptors per channel (default: 64)");
71 
72 struct pch_dma_desc_regs {
73 	u32	dev_addr;
74 	u32	mem_addr;
75 	u32	size;
76 	u32	next;
77 };
78 
79 struct pch_dma_regs {
80 	u32	dma_ctl0;
81 	u32	dma_ctl1;
82 	u32	dma_ctl2;
83 	u32	dma_ctl3;
84 	u32	dma_sts0;
85 	u32	dma_sts1;
86 	u32	dma_sts2;
87 	u32	reserved3;
88 	struct pch_dma_desc_regs desc[MAX_CHAN_NR];
89 };
90 
91 struct pch_dma_desc {
92 	struct pch_dma_desc_regs regs;
93 	struct dma_async_tx_descriptor txd;
94 	struct list_head	desc_node;
95 	struct list_head	tx_list;
96 };
97 
98 struct pch_dma_chan {
99 	struct dma_chan		chan;
100 	void __iomem *membase;
101 	enum dma_transfer_direction dir;
102 	struct tasklet_struct	tasklet;
103 	unsigned long		err_status;
104 
105 	spinlock_t		lock;
106 
107 	struct list_head	active_list;
108 	struct list_head	queue;
109 	struct list_head	free_list;
110 	unsigned int		descs_allocated;
111 };
112 
113 #define PDC_DEV_ADDR	0x00
114 #define PDC_MEM_ADDR	0x04
115 #define PDC_SIZE	0x08
116 #define PDC_NEXT	0x0C
117 
118 #define channel_readl(pdc, name) \
119 	readl((pdc)->membase + PDC_##name)
120 #define channel_writel(pdc, name, val) \
121 	writel((val), (pdc)->membase + PDC_##name)
122 
123 struct pch_dma {
124 	struct dma_device	dma;
125 	void __iomem *membase;
126 	struct dma_pool		*pool;
127 	struct pch_dma_regs	regs;
128 	struct pch_dma_desc_regs ch_regs[MAX_CHAN_NR];
129 	struct pch_dma_chan	channels[MAX_CHAN_NR];
130 };
131 
132 #define PCH_DMA_CTL0	0x00
133 #define PCH_DMA_CTL1	0x04
134 #define PCH_DMA_CTL2	0x08
135 #define PCH_DMA_CTL3	0x0C
136 #define PCH_DMA_STS0	0x10
137 #define PCH_DMA_STS1	0x14
138 #define PCH_DMA_STS2	0x18
139 
140 #define dma_readl(pd, name) \
141 	readl((pd)->membase + PCH_DMA_##name)
142 #define dma_writel(pd, name, val) \
143 	writel((val), (pd)->membase + PCH_DMA_##name)
144 
145 static inline
146 struct pch_dma_desc *to_pd_desc(struct dma_async_tx_descriptor *txd)
147 {
148 	return container_of(txd, struct pch_dma_desc, txd);
149 }
150 
151 static inline struct pch_dma_chan *to_pd_chan(struct dma_chan *chan)
152 {
153 	return container_of(chan, struct pch_dma_chan, chan);
154 }
155 
156 static inline struct pch_dma *to_pd(struct dma_device *ddev)
157 {
158 	return container_of(ddev, struct pch_dma, dma);
159 }
160 
161 static inline struct device *chan2dev(struct dma_chan *chan)
162 {
163 	return &chan->dev->device;
164 }
165 
166 static inline struct device *chan2parent(struct dma_chan *chan)
167 {
168 	return chan->dev->device.parent;
169 }
170 
171 static inline
172 struct pch_dma_desc *pdc_first_active(struct pch_dma_chan *pd_chan)
173 {
174 	return list_first_entry(&pd_chan->active_list,
175 				struct pch_dma_desc, desc_node);
176 }
177 
178 static inline
179 struct pch_dma_desc *pdc_first_queued(struct pch_dma_chan *pd_chan)
180 {
181 	return list_first_entry(&pd_chan->queue,
182 				struct pch_dma_desc, desc_node);
183 }
184 
185 static void pdc_enable_irq(struct dma_chan *chan, int enable)
186 {
187 	struct pch_dma *pd = to_pd(chan->device);
188 	u32 val;
189 	int pos;
190 
191 	if (chan->chan_id < 8)
192 		pos = chan->chan_id;
193 	else
194 		pos = chan->chan_id + 8;
195 
196 	val = dma_readl(pd, CTL2);
197 
198 	if (enable)
199 		val |= 0x1 << pos;
200 	else
201 		val &= ~(0x1 << pos);
202 
203 	dma_writel(pd, CTL2, val);
204 
205 	dev_dbg(chan2dev(chan), "pdc_enable_irq: chan %d -> %x\n",
206 		chan->chan_id, val);
207 }
208 
209 static void pdc_set_dir(struct dma_chan *chan)
210 {
211 	struct pch_dma_chan *pd_chan = to_pd_chan(chan);
212 	struct pch_dma *pd = to_pd(chan->device);
213 	u32 val;
214 	u32 mask_mode;
215 	u32 mask_ctl;
216 
217 	if (chan->chan_id < 8) {
218 		val = dma_readl(pd, CTL0);
219 
220 		mask_mode = DMA_CTL0_MODE_MASK_BITS <<
221 					(DMA_CTL0_BITS_PER_CH * chan->chan_id);
222 		mask_ctl = DMA_MASK_CTL0_MODE & ~(DMA_CTL0_MODE_MASK_BITS <<
223 				       (DMA_CTL0_BITS_PER_CH * chan->chan_id));
224 		val &= mask_mode;
225 		if (pd_chan->dir == DMA_MEM_TO_DEV)
226 			val |= 0x1 << (DMA_CTL0_BITS_PER_CH * chan->chan_id +
227 				       DMA_CTL0_DIR_SHIFT_BITS);
228 		else
229 			val &= ~(0x1 << (DMA_CTL0_BITS_PER_CH * chan->chan_id +
230 					 DMA_CTL0_DIR_SHIFT_BITS));
231 
232 		val |= mask_ctl;
233 		dma_writel(pd, CTL0, val);
234 	} else {
235 		int ch = chan->chan_id - 8; /* ch8-->0 ch9-->1 ... ch11->3 */
236 		val = dma_readl(pd, CTL3);
237 
238 		mask_mode = DMA_CTL0_MODE_MASK_BITS <<
239 						(DMA_CTL0_BITS_PER_CH * ch);
240 		mask_ctl = DMA_MASK_CTL2_MODE & ~(DMA_CTL0_MODE_MASK_BITS <<
241 						 (DMA_CTL0_BITS_PER_CH * ch));
242 		val &= mask_mode;
243 		if (pd_chan->dir == DMA_MEM_TO_DEV)
244 			val |= 0x1 << (DMA_CTL0_BITS_PER_CH * ch +
245 				       DMA_CTL0_DIR_SHIFT_BITS);
246 		else
247 			val &= ~(0x1 << (DMA_CTL0_BITS_PER_CH * ch +
248 					 DMA_CTL0_DIR_SHIFT_BITS));
249 		val |= mask_ctl;
250 		dma_writel(pd, CTL3, val);
251 	}
252 
253 	dev_dbg(chan2dev(chan), "pdc_set_dir: chan %d -> %x\n",
254 		chan->chan_id, val);
255 }
256 
257 static void pdc_set_mode(struct dma_chan *chan, u32 mode)
258 {
259 	struct pch_dma *pd = to_pd(chan->device);
260 	u32 val;
261 	u32 mask_ctl;
262 	u32 mask_dir;
263 
264 	if (chan->chan_id < 8) {
265 		mask_ctl = DMA_MASK_CTL0_MODE & ~(DMA_CTL0_MODE_MASK_BITS <<
266 			   (DMA_CTL0_BITS_PER_CH * chan->chan_id));
267 		mask_dir = 1 << (DMA_CTL0_BITS_PER_CH * chan->chan_id +\
268 				 DMA_CTL0_DIR_SHIFT_BITS);
269 		val = dma_readl(pd, CTL0);
270 		val &= mask_dir;
271 		val |= mode << (DMA_CTL0_BITS_PER_CH * chan->chan_id);
272 		val |= mask_ctl;
273 		dma_writel(pd, CTL0, val);
274 	} else {
275 		int ch = chan->chan_id - 8; /* ch8-->0 ch9-->1 ... ch11->3 */
276 		mask_ctl = DMA_MASK_CTL2_MODE & ~(DMA_CTL0_MODE_MASK_BITS <<
277 						 (DMA_CTL0_BITS_PER_CH * ch));
278 		mask_dir = 1 << (DMA_CTL0_BITS_PER_CH * ch +\
279 				 DMA_CTL0_DIR_SHIFT_BITS);
280 		val = dma_readl(pd, CTL3);
281 		val &= mask_dir;
282 		val |= mode << (DMA_CTL0_BITS_PER_CH * ch);
283 		val |= mask_ctl;
284 		dma_writel(pd, CTL3, val);
285 	}
286 
287 	dev_dbg(chan2dev(chan), "pdc_set_mode: chan %d -> %x\n",
288 		chan->chan_id, val);
289 }
290 
291 static u32 pdc_get_status0(struct pch_dma_chan *pd_chan)
292 {
293 	struct pch_dma *pd = to_pd(pd_chan->chan.device);
294 	u32 val;
295 
296 	val = dma_readl(pd, STS0);
297 	return DMA_STATUS_MASK_BITS & (val >> (DMA_STATUS_SHIFT_BITS +
298 			DMA_STATUS_BITS_PER_CH * pd_chan->chan.chan_id));
299 }
300 
301 static u32 pdc_get_status2(struct pch_dma_chan *pd_chan)
302 {
303 	struct pch_dma *pd = to_pd(pd_chan->chan.device);
304 	u32 val;
305 
306 	val = dma_readl(pd, STS2);
307 	return DMA_STATUS_MASK_BITS & (val >> (DMA_STATUS_SHIFT_BITS +
308 			DMA_STATUS_BITS_PER_CH * (pd_chan->chan.chan_id - 8)));
309 }
310 
311 static bool pdc_is_idle(struct pch_dma_chan *pd_chan)
312 {
313 	u32 sts;
314 
315 	if (pd_chan->chan.chan_id < 8)
316 		sts = pdc_get_status0(pd_chan);
317 	else
318 		sts = pdc_get_status2(pd_chan);
319 
320 
321 	if (sts == DMA_STATUS_IDLE)
322 		return true;
323 	else
324 		return false;
325 }
326 
327 static void pdc_dostart(struct pch_dma_chan *pd_chan, struct pch_dma_desc* desc)
328 {
329 	if (!pdc_is_idle(pd_chan)) {
330 		dev_err(chan2dev(&pd_chan->chan),
331 			"BUG: Attempt to start non-idle channel\n");
332 		return;
333 	}
334 
335 	dev_dbg(chan2dev(&pd_chan->chan), "chan %d -> dev_addr: %x\n",
336 		pd_chan->chan.chan_id, desc->regs.dev_addr);
337 	dev_dbg(chan2dev(&pd_chan->chan), "chan %d -> mem_addr: %x\n",
338 		pd_chan->chan.chan_id, desc->regs.mem_addr);
339 	dev_dbg(chan2dev(&pd_chan->chan), "chan %d -> size: %x\n",
340 		pd_chan->chan.chan_id, desc->regs.size);
341 	dev_dbg(chan2dev(&pd_chan->chan), "chan %d -> next: %x\n",
342 		pd_chan->chan.chan_id, desc->regs.next);
343 
344 	if (list_empty(&desc->tx_list)) {
345 		channel_writel(pd_chan, DEV_ADDR, desc->regs.dev_addr);
346 		channel_writel(pd_chan, MEM_ADDR, desc->regs.mem_addr);
347 		channel_writel(pd_chan, SIZE, desc->regs.size);
348 		channel_writel(pd_chan, NEXT, desc->regs.next);
349 		pdc_set_mode(&pd_chan->chan, DMA_CTL0_ONESHOT);
350 	} else {
351 		channel_writel(pd_chan, NEXT, desc->txd.phys);
352 		pdc_set_mode(&pd_chan->chan, DMA_CTL0_SG);
353 	}
354 }
355 
356 static void pdc_chain_complete(struct pch_dma_chan *pd_chan,
357 			       struct pch_dma_desc *desc)
358 {
359 	struct dma_async_tx_descriptor *txd = &desc->txd;
360 	struct dmaengine_desc_callback cb;
361 
362 	dmaengine_desc_get_callback(txd, &cb);
363 	list_splice_init(&desc->tx_list, &pd_chan->free_list);
364 	list_move(&desc->desc_node, &pd_chan->free_list);
365 
366 	dmaengine_desc_callback_invoke(&cb, NULL);
367 }
368 
369 static void pdc_complete_all(struct pch_dma_chan *pd_chan)
370 {
371 	struct pch_dma_desc *desc, *_d;
372 	LIST_HEAD(list);
373 
374 	BUG_ON(!pdc_is_idle(pd_chan));
375 
376 	if (!list_empty(&pd_chan->queue))
377 		pdc_dostart(pd_chan, pdc_first_queued(pd_chan));
378 
379 	list_splice_init(&pd_chan->active_list, &list);
380 	list_splice_init(&pd_chan->queue, &pd_chan->active_list);
381 
382 	list_for_each_entry_safe(desc, _d, &list, desc_node)
383 		pdc_chain_complete(pd_chan, desc);
384 }
385 
386 static void pdc_handle_error(struct pch_dma_chan *pd_chan)
387 {
388 	struct pch_dma_desc *bad_desc;
389 
390 	bad_desc = pdc_first_active(pd_chan);
391 	list_del(&bad_desc->desc_node);
392 
393 	list_splice_init(&pd_chan->queue, pd_chan->active_list.prev);
394 
395 	if (!list_empty(&pd_chan->active_list))
396 		pdc_dostart(pd_chan, pdc_first_active(pd_chan));
397 
398 	dev_crit(chan2dev(&pd_chan->chan), "Bad descriptor submitted\n");
399 	dev_crit(chan2dev(&pd_chan->chan), "descriptor cookie: %d\n",
400 		 bad_desc->txd.cookie);
401 
402 	pdc_chain_complete(pd_chan, bad_desc);
403 }
404 
405 static void pdc_advance_work(struct pch_dma_chan *pd_chan)
406 {
407 	if (list_empty(&pd_chan->active_list) ||
408 		list_is_singular(&pd_chan->active_list)) {
409 		pdc_complete_all(pd_chan);
410 	} else {
411 		pdc_chain_complete(pd_chan, pdc_first_active(pd_chan));
412 		pdc_dostart(pd_chan, pdc_first_active(pd_chan));
413 	}
414 }
415 
416 static dma_cookie_t pd_tx_submit(struct dma_async_tx_descriptor *txd)
417 {
418 	struct pch_dma_desc *desc = to_pd_desc(txd);
419 	struct pch_dma_chan *pd_chan = to_pd_chan(txd->chan);
420 
421 	spin_lock(&pd_chan->lock);
422 
423 	if (list_empty(&pd_chan->active_list)) {
424 		list_add_tail(&desc->desc_node, &pd_chan->active_list);
425 		pdc_dostart(pd_chan, desc);
426 	} else {
427 		list_add_tail(&desc->desc_node, &pd_chan->queue);
428 	}
429 
430 	spin_unlock(&pd_chan->lock);
431 	return 0;
432 }
433 
434 static struct pch_dma_desc *pdc_alloc_desc(struct dma_chan *chan, gfp_t flags)
435 {
436 	struct pch_dma_desc *desc = NULL;
437 	struct pch_dma *pd = to_pd(chan->device);
438 	dma_addr_t addr;
439 
440 	desc = dma_pool_zalloc(pd->pool, flags, &addr);
441 	if (desc) {
442 		INIT_LIST_HEAD(&desc->tx_list);
443 		dma_async_tx_descriptor_init(&desc->txd, chan);
444 		desc->txd.tx_submit = pd_tx_submit;
445 		desc->txd.flags = DMA_CTRL_ACK;
446 		desc->txd.phys = addr;
447 	}
448 
449 	return desc;
450 }
451 
452 static struct pch_dma_desc *pdc_desc_get(struct pch_dma_chan *pd_chan)
453 {
454 	struct pch_dma_desc *desc, *_d;
455 	struct pch_dma_desc *ret = NULL;
456 	int i = 0;
457 
458 	spin_lock(&pd_chan->lock);
459 	list_for_each_entry_safe(desc, _d, &pd_chan->free_list, desc_node) {
460 		i++;
461 		if (async_tx_test_ack(&desc->txd)) {
462 			list_del(&desc->desc_node);
463 			ret = desc;
464 			break;
465 		}
466 		dev_dbg(chan2dev(&pd_chan->chan), "desc %p not ACKed\n", desc);
467 	}
468 	spin_unlock(&pd_chan->lock);
469 	dev_dbg(chan2dev(&pd_chan->chan), "scanned %d descriptors\n", i);
470 
471 	if (!ret) {
472 		ret = pdc_alloc_desc(&pd_chan->chan, GFP_ATOMIC);
473 		if (ret) {
474 			spin_lock(&pd_chan->lock);
475 			pd_chan->descs_allocated++;
476 			spin_unlock(&pd_chan->lock);
477 		} else {
478 			dev_err(chan2dev(&pd_chan->chan),
479 				"failed to alloc desc\n");
480 		}
481 	}
482 
483 	return ret;
484 }
485 
486 static void pdc_desc_put(struct pch_dma_chan *pd_chan,
487 			 struct pch_dma_desc *desc)
488 {
489 	if (desc) {
490 		spin_lock(&pd_chan->lock);
491 		list_splice_init(&desc->tx_list, &pd_chan->free_list);
492 		list_add(&desc->desc_node, &pd_chan->free_list);
493 		spin_unlock(&pd_chan->lock);
494 	}
495 }
496 
497 static int pd_alloc_chan_resources(struct dma_chan *chan)
498 {
499 	struct pch_dma_chan *pd_chan = to_pd_chan(chan);
500 	struct pch_dma_desc *desc;
501 	LIST_HEAD(tmp_list);
502 	int i;
503 
504 	if (!pdc_is_idle(pd_chan)) {
505 		dev_dbg(chan2dev(chan), "DMA channel not idle ?\n");
506 		return -EIO;
507 	}
508 
509 	if (!list_empty(&pd_chan->free_list))
510 		return pd_chan->descs_allocated;
511 
512 	for (i = 0; i < init_nr_desc_per_channel; i++) {
513 		desc = pdc_alloc_desc(chan, GFP_KERNEL);
514 
515 		if (!desc) {
516 			dev_warn(chan2dev(chan),
517 				"Only allocated %d initial descriptors\n", i);
518 			break;
519 		}
520 
521 		list_add_tail(&desc->desc_node, &tmp_list);
522 	}
523 
524 	spin_lock_irq(&pd_chan->lock);
525 	list_splice(&tmp_list, &pd_chan->free_list);
526 	pd_chan->descs_allocated = i;
527 	dma_cookie_init(chan);
528 	spin_unlock_irq(&pd_chan->lock);
529 
530 	pdc_enable_irq(chan, 1);
531 
532 	return pd_chan->descs_allocated;
533 }
534 
535 static void pd_free_chan_resources(struct dma_chan *chan)
536 {
537 	struct pch_dma_chan *pd_chan = to_pd_chan(chan);
538 	struct pch_dma *pd = to_pd(chan->device);
539 	struct pch_dma_desc *desc, *_d;
540 	LIST_HEAD(tmp_list);
541 
542 	BUG_ON(!pdc_is_idle(pd_chan));
543 	BUG_ON(!list_empty(&pd_chan->active_list));
544 	BUG_ON(!list_empty(&pd_chan->queue));
545 
546 	spin_lock_irq(&pd_chan->lock);
547 	list_splice_init(&pd_chan->free_list, &tmp_list);
548 	pd_chan->descs_allocated = 0;
549 	spin_unlock_irq(&pd_chan->lock);
550 
551 	list_for_each_entry_safe(desc, _d, &tmp_list, desc_node)
552 		dma_pool_free(pd->pool, desc, desc->txd.phys);
553 
554 	pdc_enable_irq(chan, 0);
555 }
556 
557 static enum dma_status pd_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
558 				    struct dma_tx_state *txstate)
559 {
560 	return dma_cookie_status(chan, cookie, txstate);
561 }
562 
563 static void pd_issue_pending(struct dma_chan *chan)
564 {
565 	struct pch_dma_chan *pd_chan = to_pd_chan(chan);
566 
567 	if (pdc_is_idle(pd_chan)) {
568 		spin_lock(&pd_chan->lock);
569 		pdc_advance_work(pd_chan);
570 		spin_unlock(&pd_chan->lock);
571 	}
572 }
573 
574 static struct dma_async_tx_descriptor *pd_prep_slave_sg(struct dma_chan *chan,
575 			struct scatterlist *sgl, unsigned int sg_len,
576 			enum dma_transfer_direction direction, unsigned long flags,
577 			void *context)
578 {
579 	struct pch_dma_chan *pd_chan = to_pd_chan(chan);
580 	struct pch_dma_slave *pd_slave = chan->private;
581 	struct pch_dma_desc *first = NULL;
582 	struct pch_dma_desc *prev = NULL;
583 	struct pch_dma_desc *desc = NULL;
584 	struct scatterlist *sg;
585 	dma_addr_t reg;
586 	int i;
587 
588 	if (unlikely(!sg_len)) {
589 		dev_info(chan2dev(chan), "prep_slave_sg: length is zero!\n");
590 		return NULL;
591 	}
592 
593 	if (direction == DMA_DEV_TO_MEM)
594 		reg = pd_slave->rx_reg;
595 	else if (direction == DMA_MEM_TO_DEV)
596 		reg = pd_slave->tx_reg;
597 	else
598 		return NULL;
599 
600 	pd_chan->dir = direction;
601 	pdc_set_dir(chan);
602 
603 	for_each_sg(sgl, sg, sg_len, i) {
604 		desc = pdc_desc_get(pd_chan);
605 
606 		if (!desc)
607 			goto err_desc_get;
608 
609 		desc->regs.dev_addr = reg;
610 		desc->regs.mem_addr = sg_dma_address(sg);
611 		desc->regs.size = sg_dma_len(sg);
612 		desc->regs.next = DMA_DESC_FOLLOW_WITHOUT_IRQ;
613 
614 		switch (pd_slave->width) {
615 		case PCH_DMA_WIDTH_1_BYTE:
616 			if (desc->regs.size > DMA_DESC_MAX_COUNT_1_BYTE)
617 				goto err_desc_get;
618 			desc->regs.size |= DMA_DESC_WIDTH_1_BYTE;
619 			break;
620 		case PCH_DMA_WIDTH_2_BYTES:
621 			if (desc->regs.size > DMA_DESC_MAX_COUNT_2_BYTES)
622 				goto err_desc_get;
623 			desc->regs.size |= DMA_DESC_WIDTH_2_BYTES;
624 			break;
625 		case PCH_DMA_WIDTH_4_BYTES:
626 			if (desc->regs.size > DMA_DESC_MAX_COUNT_4_BYTES)
627 				goto err_desc_get;
628 			desc->regs.size |= DMA_DESC_WIDTH_4_BYTES;
629 			break;
630 		default:
631 			goto err_desc_get;
632 		}
633 
634 		if (!first) {
635 			first = desc;
636 		} else {
637 			prev->regs.next |= desc->txd.phys;
638 			list_add_tail(&desc->desc_node, &first->tx_list);
639 		}
640 
641 		prev = desc;
642 	}
643 
644 	if (flags & DMA_PREP_INTERRUPT)
645 		desc->regs.next = DMA_DESC_END_WITH_IRQ;
646 	else
647 		desc->regs.next = DMA_DESC_END_WITHOUT_IRQ;
648 
649 	first->txd.cookie = -EBUSY;
650 	desc->txd.flags = flags;
651 
652 	return &first->txd;
653 
654 err_desc_get:
655 	dev_err(chan2dev(chan), "failed to get desc or wrong parameters\n");
656 	pdc_desc_put(pd_chan, first);
657 	return NULL;
658 }
659 
660 static int pd_device_terminate_all(struct dma_chan *chan)
661 {
662 	struct pch_dma_chan *pd_chan = to_pd_chan(chan);
663 	struct pch_dma_desc *desc, *_d;
664 	LIST_HEAD(list);
665 
666 	spin_lock_irq(&pd_chan->lock);
667 
668 	pdc_set_mode(&pd_chan->chan, DMA_CTL0_DISABLE);
669 
670 	list_splice_init(&pd_chan->active_list, &list);
671 	list_splice_init(&pd_chan->queue, &list);
672 
673 	list_for_each_entry_safe(desc, _d, &list, desc_node)
674 		pdc_chain_complete(pd_chan, desc);
675 
676 	spin_unlock_irq(&pd_chan->lock);
677 
678 	return 0;
679 }
680 
681 static void pdc_tasklet(unsigned long data)
682 {
683 	struct pch_dma_chan *pd_chan = (struct pch_dma_chan *)data;
684 	unsigned long flags;
685 
686 	if (!pdc_is_idle(pd_chan)) {
687 		dev_err(chan2dev(&pd_chan->chan),
688 			"BUG: handle non-idle channel in tasklet\n");
689 		return;
690 	}
691 
692 	spin_lock_irqsave(&pd_chan->lock, flags);
693 	if (test_and_clear_bit(0, &pd_chan->err_status))
694 		pdc_handle_error(pd_chan);
695 	else
696 		pdc_advance_work(pd_chan);
697 	spin_unlock_irqrestore(&pd_chan->lock, flags);
698 }
699 
700 static irqreturn_t pd_irq(int irq, void *devid)
701 {
702 	struct pch_dma *pd = (struct pch_dma *)devid;
703 	struct pch_dma_chan *pd_chan;
704 	u32 sts0;
705 	u32 sts2;
706 	int i;
707 	int ret0 = IRQ_NONE;
708 	int ret2 = IRQ_NONE;
709 
710 	sts0 = dma_readl(pd, STS0);
711 	sts2 = dma_readl(pd, STS2);
712 
713 	dev_dbg(pd->dma.dev, "pd_irq sts0: %x\n", sts0);
714 
715 	for (i = 0; i < pd->dma.chancnt; i++) {
716 		pd_chan = &pd->channels[i];
717 
718 		if (i < 8) {
719 			if (sts0 & DMA_STATUS_IRQ(i)) {
720 				if (sts0 & DMA_STATUS0_ERR(i))
721 					set_bit(0, &pd_chan->err_status);
722 
723 				tasklet_schedule(&pd_chan->tasklet);
724 				ret0 = IRQ_HANDLED;
725 			}
726 		} else {
727 			if (sts2 & DMA_STATUS_IRQ(i - 8)) {
728 				if (sts2 & DMA_STATUS2_ERR(i))
729 					set_bit(0, &pd_chan->err_status);
730 
731 				tasklet_schedule(&pd_chan->tasklet);
732 				ret2 = IRQ_HANDLED;
733 			}
734 		}
735 	}
736 
737 	/* clear interrupt bits in status register */
738 	if (ret0)
739 		dma_writel(pd, STS0, sts0);
740 	if (ret2)
741 		dma_writel(pd, STS2, sts2);
742 
743 	return ret0 | ret2;
744 }
745 
746 #ifdef	CONFIG_PM
747 static void pch_dma_save_regs(struct pch_dma *pd)
748 {
749 	struct pch_dma_chan *pd_chan;
750 	struct dma_chan *chan, *_c;
751 	int i = 0;
752 
753 	pd->regs.dma_ctl0 = dma_readl(pd, CTL0);
754 	pd->regs.dma_ctl1 = dma_readl(pd, CTL1);
755 	pd->regs.dma_ctl2 = dma_readl(pd, CTL2);
756 	pd->regs.dma_ctl3 = dma_readl(pd, CTL3);
757 
758 	list_for_each_entry_safe(chan, _c, &pd->dma.channels, device_node) {
759 		pd_chan = to_pd_chan(chan);
760 
761 		pd->ch_regs[i].dev_addr = channel_readl(pd_chan, DEV_ADDR);
762 		pd->ch_regs[i].mem_addr = channel_readl(pd_chan, MEM_ADDR);
763 		pd->ch_regs[i].size = channel_readl(pd_chan, SIZE);
764 		pd->ch_regs[i].next = channel_readl(pd_chan, NEXT);
765 
766 		i++;
767 	}
768 }
769 
770 static void pch_dma_restore_regs(struct pch_dma *pd)
771 {
772 	struct pch_dma_chan *pd_chan;
773 	struct dma_chan *chan, *_c;
774 	int i = 0;
775 
776 	dma_writel(pd, CTL0, pd->regs.dma_ctl0);
777 	dma_writel(pd, CTL1, pd->regs.dma_ctl1);
778 	dma_writel(pd, CTL2, pd->regs.dma_ctl2);
779 	dma_writel(pd, CTL3, pd->regs.dma_ctl3);
780 
781 	list_for_each_entry_safe(chan, _c, &pd->dma.channels, device_node) {
782 		pd_chan = to_pd_chan(chan);
783 
784 		channel_writel(pd_chan, DEV_ADDR, pd->ch_regs[i].dev_addr);
785 		channel_writel(pd_chan, MEM_ADDR, pd->ch_regs[i].mem_addr);
786 		channel_writel(pd_chan, SIZE, pd->ch_regs[i].size);
787 		channel_writel(pd_chan, NEXT, pd->ch_regs[i].next);
788 
789 		i++;
790 	}
791 }
792 
793 static int pch_dma_suspend(struct pci_dev *pdev, pm_message_t state)
794 {
795 	struct pch_dma *pd = pci_get_drvdata(pdev);
796 
797 	if (pd)
798 		pch_dma_save_regs(pd);
799 
800 	pci_save_state(pdev);
801 	pci_disable_device(pdev);
802 	pci_set_power_state(pdev, pci_choose_state(pdev, state));
803 
804 	return 0;
805 }
806 
807 static int pch_dma_resume(struct pci_dev *pdev)
808 {
809 	struct pch_dma *pd = pci_get_drvdata(pdev);
810 	int err;
811 
812 	pci_set_power_state(pdev, PCI_D0);
813 	pci_restore_state(pdev);
814 
815 	err = pci_enable_device(pdev);
816 	if (err) {
817 		dev_dbg(&pdev->dev, "failed to enable device\n");
818 		return err;
819 	}
820 
821 	if (pd)
822 		pch_dma_restore_regs(pd);
823 
824 	return 0;
825 }
826 #endif
827 
828 static int pch_dma_probe(struct pci_dev *pdev,
829 				   const struct pci_device_id *id)
830 {
831 	struct pch_dma *pd;
832 	struct pch_dma_regs *regs;
833 	unsigned int nr_channels;
834 	int err;
835 	int i;
836 
837 	nr_channels = id->driver_data;
838 	pd = kzalloc(sizeof(*pd), GFP_KERNEL);
839 	if (!pd)
840 		return -ENOMEM;
841 
842 	pci_set_drvdata(pdev, pd);
843 
844 	err = pci_enable_device(pdev);
845 	if (err) {
846 		dev_err(&pdev->dev, "Cannot enable PCI device\n");
847 		goto err_free_mem;
848 	}
849 
850 	if (!(pci_resource_flags(pdev, 1) & IORESOURCE_MEM)) {
851 		dev_err(&pdev->dev, "Cannot find proper base address\n");
852 		err = -ENODEV;
853 		goto err_disable_pdev;
854 	}
855 
856 	err = pci_request_regions(pdev, DRV_NAME);
857 	if (err) {
858 		dev_err(&pdev->dev, "Cannot obtain PCI resources\n");
859 		goto err_disable_pdev;
860 	}
861 
862 	err = pci_set_dma_mask(pdev, DMA_BIT_MASK(32));
863 	if (err) {
864 		dev_err(&pdev->dev, "Cannot set proper DMA config\n");
865 		goto err_free_res;
866 	}
867 
868 	regs = pd->membase = pci_iomap(pdev, 1, 0);
869 	if (!pd->membase) {
870 		dev_err(&pdev->dev, "Cannot map MMIO registers\n");
871 		err = -ENOMEM;
872 		goto err_free_res;
873 	}
874 
875 	pci_set_master(pdev);
876 
877 	err = request_irq(pdev->irq, pd_irq, IRQF_SHARED, DRV_NAME, pd);
878 	if (err) {
879 		dev_err(&pdev->dev, "Failed to request IRQ\n");
880 		goto err_iounmap;
881 	}
882 
883 	pd->pool = dma_pool_create("pch_dma_desc_pool", &pdev->dev,
884 				   sizeof(struct pch_dma_desc), 4, 0);
885 	if (!pd->pool) {
886 		dev_err(&pdev->dev, "Failed to alloc DMA descriptors\n");
887 		err = -ENOMEM;
888 		goto err_free_irq;
889 	}
890 
891 	pd->dma.dev = &pdev->dev;
892 
893 	INIT_LIST_HEAD(&pd->dma.channels);
894 
895 	for (i = 0; i < nr_channels; i++) {
896 		struct pch_dma_chan *pd_chan = &pd->channels[i];
897 
898 		pd_chan->chan.device = &pd->dma;
899 		dma_cookie_init(&pd_chan->chan);
900 
901 		pd_chan->membase = &regs->desc[i];
902 
903 		spin_lock_init(&pd_chan->lock);
904 
905 		INIT_LIST_HEAD(&pd_chan->active_list);
906 		INIT_LIST_HEAD(&pd_chan->queue);
907 		INIT_LIST_HEAD(&pd_chan->free_list);
908 
909 		tasklet_init(&pd_chan->tasklet, pdc_tasklet,
910 			     (unsigned long)pd_chan);
911 		list_add_tail(&pd_chan->chan.device_node, &pd->dma.channels);
912 	}
913 
914 	dma_cap_zero(pd->dma.cap_mask);
915 	dma_cap_set(DMA_PRIVATE, pd->dma.cap_mask);
916 	dma_cap_set(DMA_SLAVE, pd->dma.cap_mask);
917 
918 	pd->dma.device_alloc_chan_resources = pd_alloc_chan_resources;
919 	pd->dma.device_free_chan_resources = pd_free_chan_resources;
920 	pd->dma.device_tx_status = pd_tx_status;
921 	pd->dma.device_issue_pending = pd_issue_pending;
922 	pd->dma.device_prep_slave_sg = pd_prep_slave_sg;
923 	pd->dma.device_terminate_all = pd_device_terminate_all;
924 
925 	err = dma_async_device_register(&pd->dma);
926 	if (err) {
927 		dev_err(&pdev->dev, "Failed to register DMA device\n");
928 		goto err_free_pool;
929 	}
930 
931 	return 0;
932 
933 err_free_pool:
934 	dma_pool_destroy(pd->pool);
935 err_free_irq:
936 	free_irq(pdev->irq, pd);
937 err_iounmap:
938 	pci_iounmap(pdev, pd->membase);
939 err_free_res:
940 	pci_release_regions(pdev);
941 err_disable_pdev:
942 	pci_disable_device(pdev);
943 err_free_mem:
944 	kfree(pd);
945 	return err;
946 }
947 
948 static void pch_dma_remove(struct pci_dev *pdev)
949 {
950 	struct pch_dma *pd = pci_get_drvdata(pdev);
951 	struct pch_dma_chan *pd_chan;
952 	struct dma_chan *chan, *_c;
953 
954 	if (pd) {
955 		dma_async_device_unregister(&pd->dma);
956 
957 		free_irq(pdev->irq, pd);
958 
959 		list_for_each_entry_safe(chan, _c, &pd->dma.channels,
960 					 device_node) {
961 			pd_chan = to_pd_chan(chan);
962 
963 			tasklet_kill(&pd_chan->tasklet);
964 		}
965 
966 		dma_pool_destroy(pd->pool);
967 		pci_iounmap(pdev, pd->membase);
968 		pci_release_regions(pdev);
969 		pci_disable_device(pdev);
970 		kfree(pd);
971 	}
972 }
973 
974 /* PCI Device ID of DMA device */
975 #define PCI_VENDOR_ID_ROHM             0x10DB
976 #define PCI_DEVICE_ID_EG20T_PCH_DMA_8CH        0x8810
977 #define PCI_DEVICE_ID_EG20T_PCH_DMA_4CH        0x8815
978 #define PCI_DEVICE_ID_ML7213_DMA1_8CH	0x8026
979 #define PCI_DEVICE_ID_ML7213_DMA2_8CH	0x802B
980 #define PCI_DEVICE_ID_ML7213_DMA3_4CH	0x8034
981 #define PCI_DEVICE_ID_ML7213_DMA4_12CH	0x8032
982 #define PCI_DEVICE_ID_ML7223_DMA1_4CH	0x800B
983 #define PCI_DEVICE_ID_ML7223_DMA2_4CH	0x800E
984 #define PCI_DEVICE_ID_ML7223_DMA3_4CH	0x8017
985 #define PCI_DEVICE_ID_ML7223_DMA4_4CH	0x803B
986 #define PCI_DEVICE_ID_ML7831_DMA1_8CH	0x8810
987 #define PCI_DEVICE_ID_ML7831_DMA2_4CH	0x8815
988 
989 static const struct pci_device_id pch_dma_id_table[] = {
990 	{ PCI_VDEVICE(INTEL, PCI_DEVICE_ID_EG20T_PCH_DMA_8CH), 8 },
991 	{ PCI_VDEVICE(INTEL, PCI_DEVICE_ID_EG20T_PCH_DMA_4CH), 4 },
992 	{ PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7213_DMA1_8CH), 8}, /* UART Video */
993 	{ PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7213_DMA2_8CH), 8}, /* PCMIF SPI */
994 	{ PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7213_DMA3_4CH), 4}, /* FPGA */
995 	{ PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7213_DMA4_12CH), 12}, /* I2S */
996 	{ PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7223_DMA1_4CH), 4}, /* UART */
997 	{ PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7223_DMA2_4CH), 4}, /* Video SPI */
998 	{ PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7223_DMA3_4CH), 4}, /* Security */
999 	{ PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7223_DMA4_4CH), 4}, /* FPGA */
1000 	{ PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7831_DMA1_8CH), 8}, /* UART */
1001 	{ PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7831_DMA2_4CH), 4}, /* SPI */
1002 	{ 0, },
1003 };
1004 
1005 static struct pci_driver pch_dma_driver = {
1006 	.name		= DRV_NAME,
1007 	.id_table	= pch_dma_id_table,
1008 	.probe		= pch_dma_probe,
1009 	.remove		= pch_dma_remove,
1010 #ifdef CONFIG_PM
1011 	.suspend	= pch_dma_suspend,
1012 	.resume		= pch_dma_resume,
1013 #endif
1014 };
1015 
1016 module_pci_driver(pch_dma_driver);
1017 
1018 MODULE_DESCRIPTION("Intel EG20T PCH / LAPIS Semicon ML7213/ML7223/ML7831 IOH "
1019 		   "DMA controller driver");
1020 MODULE_AUTHOR("Yong Wang <yong.y.wang@intel.com>");
1021 MODULE_LICENSE("GPL v2");
1022 MODULE_DEVICE_TABLE(pci, pch_dma_id_table);
1023