xref: /openbmc/linux/drivers/dma/mpc512x_dma.c (revision 63dc02bd)
1 /*
2  * Copyright (C) Freescale Semicondutor, Inc. 2007, 2008.
3  * Copyright (C) Semihalf 2009
4  * Copyright (C) Ilya Yanok, Emcraft Systems 2010
5  *
6  * Written by Piotr Ziecik <kosmo@semihalf.com>. Hardware description
7  * (defines, structures and comments) was taken from MPC5121 DMA driver
8  * written by Hongjun Chen <hong-jun.chen@freescale.com>.
9  *
10  * Approved as OSADL project by a majority of OSADL members and funded
11  * by OSADL membership fees in 2009;  for details see www.osadl.org.
12  *
13  * This program is free software; you can redistribute it and/or modify it
14  * under the terms of the GNU General Public License as published by the Free
15  * Software Foundation; either version 2 of the License, or (at your option)
16  * any later version.
17  *
18  * This program is distributed in the hope that it will be useful, but WITHOUT
19  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
20  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
21  * more details.
22  *
23  * You should have received a copy of the GNU General Public License along with
24  * this program; if not, write to the Free Software Foundation, Inc., 59
25  * Temple Place - Suite 330, Boston, MA  02111-1307, USA.
26  *
27  * The full GNU General Public License is included in this distribution in the
28  * file called COPYING.
29  */
30 
31 /*
32  * This is initial version of MPC5121 DMA driver. Only memory to memory
33  * transfers are supported (tested using dmatest module).
34  */
35 
36 #include <linux/module.h>
37 #include <linux/dmaengine.h>
38 #include <linux/dma-mapping.h>
39 #include <linux/interrupt.h>
40 #include <linux/io.h>
41 #include <linux/slab.h>
42 #include <linux/of_device.h>
43 #include <linux/of_platform.h>
44 
45 #include <linux/random.h>
46 
47 #include "dmaengine.h"
48 
49 /* Number of DMA Transfer descriptors allocated per channel */
50 #define MPC_DMA_DESCRIPTORS	64
51 
52 /* Macro definitions */
53 #define MPC_DMA_CHANNELS	64
54 #define MPC_DMA_TCD_OFFSET	0x1000
55 
56 /* Arbitration mode of group and channel */
57 #define MPC_DMA_DMACR_EDCG	(1 << 31)
58 #define MPC_DMA_DMACR_ERGA	(1 << 3)
59 #define MPC_DMA_DMACR_ERCA	(1 << 2)
60 
61 /* Error codes */
62 #define MPC_DMA_DMAES_VLD	(1 << 31)
63 #define MPC_DMA_DMAES_GPE	(1 << 15)
64 #define MPC_DMA_DMAES_CPE	(1 << 14)
65 #define MPC_DMA_DMAES_ERRCHN(err) \
66 				(((err) >> 8) & 0x3f)
67 #define MPC_DMA_DMAES_SAE	(1 << 7)
68 #define MPC_DMA_DMAES_SOE	(1 << 6)
69 #define MPC_DMA_DMAES_DAE	(1 << 5)
70 #define MPC_DMA_DMAES_DOE	(1 << 4)
71 #define MPC_DMA_DMAES_NCE	(1 << 3)
72 #define MPC_DMA_DMAES_SGE	(1 << 2)
73 #define MPC_DMA_DMAES_SBE	(1 << 1)
74 #define MPC_DMA_DMAES_DBE	(1 << 0)
75 
76 #define MPC_DMA_DMAGPOR_SNOOP_ENABLE	(1 << 6)
77 
78 #define MPC_DMA_TSIZE_1		0x00
79 #define MPC_DMA_TSIZE_2		0x01
80 #define MPC_DMA_TSIZE_4		0x02
81 #define MPC_DMA_TSIZE_16	0x04
82 #define MPC_DMA_TSIZE_32	0x05
83 
84 /* MPC5121 DMA engine registers */
85 struct __attribute__ ((__packed__)) mpc_dma_regs {
86 	/* 0x00 */
87 	u32 dmacr;		/* DMA control register */
88 	u32 dmaes;		/* DMA error status */
89 	/* 0x08 */
90 	u32 dmaerqh;		/* DMA enable request high(channels 63~32) */
91 	u32 dmaerql;		/* DMA enable request low(channels 31~0) */
92 	u32 dmaeeih;		/* DMA enable error interrupt high(ch63~32) */
93 	u32 dmaeeil;		/* DMA enable error interrupt low(ch31~0) */
94 	/* 0x18 */
95 	u8 dmaserq;		/* DMA set enable request */
96 	u8 dmacerq;		/* DMA clear enable request */
97 	u8 dmaseei;		/* DMA set enable error interrupt */
98 	u8 dmaceei;		/* DMA clear enable error interrupt */
99 	/* 0x1c */
100 	u8 dmacint;		/* DMA clear interrupt request */
101 	u8 dmacerr;		/* DMA clear error */
102 	u8 dmassrt;		/* DMA set start bit */
103 	u8 dmacdne;		/* DMA clear DONE status bit */
104 	/* 0x20 */
105 	u32 dmainth;		/* DMA interrupt request high(ch63~32) */
106 	u32 dmaintl;		/* DMA interrupt request low(ch31~0) */
107 	u32 dmaerrh;		/* DMA error high(ch63~32) */
108 	u32 dmaerrl;		/* DMA error low(ch31~0) */
109 	/* 0x30 */
110 	u32 dmahrsh;		/* DMA hw request status high(ch63~32) */
111 	u32 dmahrsl;		/* DMA hardware request status low(ch31~0) */
112 	union {
113 		u32 dmaihsa;	/* DMA interrupt high select AXE(ch63~32) */
114 		u32 dmagpor;	/* (General purpose register on MPC8308) */
115 	};
116 	u32 dmailsa;		/* DMA interrupt low select AXE(ch31~0) */
117 	/* 0x40 ~ 0xff */
118 	u32 reserve0[48];	/* Reserved */
119 	/* 0x100 */
120 	u8 dchpri[MPC_DMA_CHANNELS];
121 	/* DMA channels(0~63) priority */
122 };
123 
124 struct __attribute__ ((__packed__)) mpc_dma_tcd {
125 	/* 0x00 */
126 	u32 saddr;		/* Source address */
127 
128 	u32 smod:5;		/* Source address modulo */
129 	u32 ssize:3;		/* Source data transfer size */
130 	u32 dmod:5;		/* Destination address modulo */
131 	u32 dsize:3;		/* Destination data transfer size */
132 	u32 soff:16;		/* Signed source address offset */
133 
134 	/* 0x08 */
135 	u32 nbytes;		/* Inner "minor" byte count */
136 	u32 slast;		/* Last source address adjustment */
137 	u32 daddr;		/* Destination address */
138 
139 	/* 0x14 */
140 	u32 citer_elink:1;	/* Enable channel-to-channel linking on
141 				 * minor loop complete
142 				 */
143 	u32 citer_linkch:6;	/* Link channel for minor loop complete */
144 	u32 citer:9;		/* Current "major" iteration count */
145 	u32 doff:16;		/* Signed destination address offset */
146 
147 	/* 0x18 */
148 	u32 dlast_sga;		/* Last Destination address adjustment/scatter
149 				 * gather address
150 				 */
151 
152 	/* 0x1c */
153 	u32 biter_elink:1;	/* Enable channel-to-channel linking on major
154 				 * loop complete
155 				 */
156 	u32 biter_linkch:6;
157 	u32 biter:9;		/* Beginning "major" iteration count */
158 	u32 bwc:2;		/* Bandwidth control */
159 	u32 major_linkch:6;	/* Link channel number */
160 	u32 done:1;		/* Channel done */
161 	u32 active:1;		/* Channel active */
162 	u32 major_elink:1;	/* Enable channel-to-channel linking on major
163 				 * loop complete
164 				 */
165 	u32 e_sg:1;		/* Enable scatter/gather processing */
166 	u32 d_req:1;		/* Disable request */
167 	u32 int_half:1;		/* Enable an interrupt when major counter is
168 				 * half complete
169 				 */
170 	u32 int_maj:1;		/* Enable an interrupt when major iteration
171 				 * count completes
172 				 */
173 	u32 start:1;		/* Channel start */
174 };
175 
176 struct mpc_dma_desc {
177 	struct dma_async_tx_descriptor	desc;
178 	struct mpc_dma_tcd		*tcd;
179 	dma_addr_t			tcd_paddr;
180 	int				error;
181 	struct list_head		node;
182 };
183 
184 struct mpc_dma_chan {
185 	struct dma_chan			chan;
186 	struct list_head		free;
187 	struct list_head		prepared;
188 	struct list_head		queued;
189 	struct list_head		active;
190 	struct list_head		completed;
191 	struct mpc_dma_tcd		*tcd;
192 	dma_addr_t			tcd_paddr;
193 
194 	/* Lock for this structure */
195 	spinlock_t			lock;
196 };
197 
198 struct mpc_dma {
199 	struct dma_device		dma;
200 	struct tasklet_struct		tasklet;
201 	struct mpc_dma_chan		channels[MPC_DMA_CHANNELS];
202 	struct mpc_dma_regs __iomem	*regs;
203 	struct mpc_dma_tcd __iomem	*tcd;
204 	int				irq;
205 	int				irq2;
206 	uint				error_status;
207 	int				is_mpc8308;
208 
209 	/* Lock for error_status field in this structure */
210 	spinlock_t			error_status_lock;
211 };
212 
213 #define DRV_NAME	"mpc512x_dma"
214 
215 /* Convert struct dma_chan to struct mpc_dma_chan */
216 static inline struct mpc_dma_chan *dma_chan_to_mpc_dma_chan(struct dma_chan *c)
217 {
218 	return container_of(c, struct mpc_dma_chan, chan);
219 }
220 
221 /* Convert struct dma_chan to struct mpc_dma */
222 static inline struct mpc_dma *dma_chan_to_mpc_dma(struct dma_chan *c)
223 {
224 	struct mpc_dma_chan *mchan = dma_chan_to_mpc_dma_chan(c);
225 	return container_of(mchan, struct mpc_dma, channels[c->chan_id]);
226 }
227 
228 /*
229  * Execute all queued DMA descriptors.
230  *
231  * Following requirements must be met while calling mpc_dma_execute():
232  * 	a) mchan->lock is acquired,
233  * 	b) mchan->active list is empty,
234  * 	c) mchan->queued list contains at least one entry.
235  */
236 static void mpc_dma_execute(struct mpc_dma_chan *mchan)
237 {
238 	struct mpc_dma *mdma = dma_chan_to_mpc_dma(&mchan->chan);
239 	struct mpc_dma_desc *first = NULL;
240 	struct mpc_dma_desc *prev = NULL;
241 	struct mpc_dma_desc *mdesc;
242 	int cid = mchan->chan.chan_id;
243 
244 	/* Move all queued descriptors to active list */
245 	list_splice_tail_init(&mchan->queued, &mchan->active);
246 
247 	/* Chain descriptors into one transaction */
248 	list_for_each_entry(mdesc, &mchan->active, node) {
249 		if (!first)
250 			first = mdesc;
251 
252 		if (!prev) {
253 			prev = mdesc;
254 			continue;
255 		}
256 
257 		prev->tcd->dlast_sga = mdesc->tcd_paddr;
258 		prev->tcd->e_sg = 1;
259 		mdesc->tcd->start = 1;
260 
261 		prev = mdesc;
262 	}
263 
264 	prev->tcd->int_maj = 1;
265 
266 	/* Send first descriptor in chain into hardware */
267 	memcpy_toio(&mdma->tcd[cid], first->tcd, sizeof(struct mpc_dma_tcd));
268 
269 	if (first != prev)
270 		mdma->tcd[cid].e_sg = 1;
271 	out_8(&mdma->regs->dmassrt, cid);
272 }
273 
274 /* Handle interrupt on one half of DMA controller (32 channels) */
275 static void mpc_dma_irq_process(struct mpc_dma *mdma, u32 is, u32 es, int off)
276 {
277 	struct mpc_dma_chan *mchan;
278 	struct mpc_dma_desc *mdesc;
279 	u32 status = is | es;
280 	int ch;
281 
282 	while ((ch = fls(status) - 1) >= 0) {
283 		status &= ~(1 << ch);
284 		mchan = &mdma->channels[ch + off];
285 
286 		spin_lock(&mchan->lock);
287 
288 		out_8(&mdma->regs->dmacint, ch + off);
289 		out_8(&mdma->regs->dmacerr, ch + off);
290 
291 		/* Check error status */
292 		if (es & (1 << ch))
293 			list_for_each_entry(mdesc, &mchan->active, node)
294 				mdesc->error = -EIO;
295 
296 		/* Execute queued descriptors */
297 		list_splice_tail_init(&mchan->active, &mchan->completed);
298 		if (!list_empty(&mchan->queued))
299 			mpc_dma_execute(mchan);
300 
301 		spin_unlock(&mchan->lock);
302 	}
303 }
304 
305 /* Interrupt handler */
306 static irqreturn_t mpc_dma_irq(int irq, void *data)
307 {
308 	struct mpc_dma *mdma = data;
309 	uint es;
310 
311 	/* Save error status register */
312 	es = in_be32(&mdma->regs->dmaes);
313 	spin_lock(&mdma->error_status_lock);
314 	if ((es & MPC_DMA_DMAES_VLD) && mdma->error_status == 0)
315 		mdma->error_status = es;
316 	spin_unlock(&mdma->error_status_lock);
317 
318 	/* Handle interrupt on each channel */
319 	if (mdma->dma.chancnt > 32) {
320 		mpc_dma_irq_process(mdma, in_be32(&mdma->regs->dmainth),
321 					in_be32(&mdma->regs->dmaerrh), 32);
322 	}
323 	mpc_dma_irq_process(mdma, in_be32(&mdma->regs->dmaintl),
324 					in_be32(&mdma->regs->dmaerrl), 0);
325 
326 	/* Schedule tasklet */
327 	tasklet_schedule(&mdma->tasklet);
328 
329 	return IRQ_HANDLED;
330 }
331 
332 /* process completed descriptors */
333 static void mpc_dma_process_completed(struct mpc_dma *mdma)
334 {
335 	dma_cookie_t last_cookie = 0;
336 	struct mpc_dma_chan *mchan;
337 	struct mpc_dma_desc *mdesc;
338 	struct dma_async_tx_descriptor *desc;
339 	unsigned long flags;
340 	LIST_HEAD(list);
341 	int i;
342 
343 	for (i = 0; i < mdma->dma.chancnt; i++) {
344 		mchan = &mdma->channels[i];
345 
346 		/* Get all completed descriptors */
347 		spin_lock_irqsave(&mchan->lock, flags);
348 		if (!list_empty(&mchan->completed))
349 			list_splice_tail_init(&mchan->completed, &list);
350 		spin_unlock_irqrestore(&mchan->lock, flags);
351 
352 		if (list_empty(&list))
353 			continue;
354 
355 		/* Execute callbacks and run dependencies */
356 		list_for_each_entry(mdesc, &list, node) {
357 			desc = &mdesc->desc;
358 
359 			if (desc->callback)
360 				desc->callback(desc->callback_param);
361 
362 			last_cookie = desc->cookie;
363 			dma_run_dependencies(desc);
364 		}
365 
366 		/* Free descriptors */
367 		spin_lock_irqsave(&mchan->lock, flags);
368 		list_splice_tail_init(&list, &mchan->free);
369 		mchan->chan.completed_cookie = last_cookie;
370 		spin_unlock_irqrestore(&mchan->lock, flags);
371 	}
372 }
373 
374 /* DMA Tasklet */
375 static void mpc_dma_tasklet(unsigned long data)
376 {
377 	struct mpc_dma *mdma = (void *)data;
378 	unsigned long flags;
379 	uint es;
380 
381 	spin_lock_irqsave(&mdma->error_status_lock, flags);
382 	es = mdma->error_status;
383 	mdma->error_status = 0;
384 	spin_unlock_irqrestore(&mdma->error_status_lock, flags);
385 
386 	/* Print nice error report */
387 	if (es) {
388 		dev_err(mdma->dma.dev,
389 			"Hardware reported following error(s) on channel %u:\n",
390 						      MPC_DMA_DMAES_ERRCHN(es));
391 
392 		if (es & MPC_DMA_DMAES_GPE)
393 			dev_err(mdma->dma.dev, "- Group Priority Error\n");
394 		if (es & MPC_DMA_DMAES_CPE)
395 			dev_err(mdma->dma.dev, "- Channel Priority Error\n");
396 		if (es & MPC_DMA_DMAES_SAE)
397 			dev_err(mdma->dma.dev, "- Source Address Error\n");
398 		if (es & MPC_DMA_DMAES_SOE)
399 			dev_err(mdma->dma.dev, "- Source Offset"
400 						" Configuration Error\n");
401 		if (es & MPC_DMA_DMAES_DAE)
402 			dev_err(mdma->dma.dev, "- Destination Address"
403 								" Error\n");
404 		if (es & MPC_DMA_DMAES_DOE)
405 			dev_err(mdma->dma.dev, "- Destination Offset"
406 						" Configuration Error\n");
407 		if (es & MPC_DMA_DMAES_NCE)
408 			dev_err(mdma->dma.dev, "- NBytes/Citter"
409 						" Configuration Error\n");
410 		if (es & MPC_DMA_DMAES_SGE)
411 			dev_err(mdma->dma.dev, "- Scatter/Gather"
412 						" Configuration Error\n");
413 		if (es & MPC_DMA_DMAES_SBE)
414 			dev_err(mdma->dma.dev, "- Source Bus Error\n");
415 		if (es & MPC_DMA_DMAES_DBE)
416 			dev_err(mdma->dma.dev, "- Destination Bus Error\n");
417 	}
418 
419 	mpc_dma_process_completed(mdma);
420 }
421 
422 /* Submit descriptor to hardware */
423 static dma_cookie_t mpc_dma_tx_submit(struct dma_async_tx_descriptor *txd)
424 {
425 	struct mpc_dma_chan *mchan = dma_chan_to_mpc_dma_chan(txd->chan);
426 	struct mpc_dma_desc *mdesc;
427 	unsigned long flags;
428 	dma_cookie_t cookie;
429 
430 	mdesc = container_of(txd, struct mpc_dma_desc, desc);
431 
432 	spin_lock_irqsave(&mchan->lock, flags);
433 
434 	/* Move descriptor to queue */
435 	list_move_tail(&mdesc->node, &mchan->queued);
436 
437 	/* If channel is idle, execute all queued descriptors */
438 	if (list_empty(&mchan->active))
439 		mpc_dma_execute(mchan);
440 
441 	/* Update cookie */
442 	cookie = dma_cookie_assign(txd);
443 	spin_unlock_irqrestore(&mchan->lock, flags);
444 
445 	return cookie;
446 }
447 
448 /* Alloc channel resources */
449 static int mpc_dma_alloc_chan_resources(struct dma_chan *chan)
450 {
451 	struct mpc_dma *mdma = dma_chan_to_mpc_dma(chan);
452 	struct mpc_dma_chan *mchan = dma_chan_to_mpc_dma_chan(chan);
453 	struct mpc_dma_desc *mdesc;
454 	struct mpc_dma_tcd *tcd;
455 	dma_addr_t tcd_paddr;
456 	unsigned long flags;
457 	LIST_HEAD(descs);
458 	int i;
459 
460 	/* Alloc DMA memory for Transfer Control Descriptors */
461 	tcd = dma_alloc_coherent(mdma->dma.dev,
462 			MPC_DMA_DESCRIPTORS * sizeof(struct mpc_dma_tcd),
463 							&tcd_paddr, GFP_KERNEL);
464 	if (!tcd)
465 		return -ENOMEM;
466 
467 	/* Alloc descriptors for this channel */
468 	for (i = 0; i < MPC_DMA_DESCRIPTORS; i++) {
469 		mdesc = kzalloc(sizeof(struct mpc_dma_desc), GFP_KERNEL);
470 		if (!mdesc) {
471 			dev_notice(mdma->dma.dev, "Memory allocation error. "
472 					"Allocated only %u descriptors\n", i);
473 			break;
474 		}
475 
476 		dma_async_tx_descriptor_init(&mdesc->desc, chan);
477 		mdesc->desc.flags = DMA_CTRL_ACK;
478 		mdesc->desc.tx_submit = mpc_dma_tx_submit;
479 
480 		mdesc->tcd = &tcd[i];
481 		mdesc->tcd_paddr = tcd_paddr + (i * sizeof(struct mpc_dma_tcd));
482 
483 		list_add_tail(&mdesc->node, &descs);
484 	}
485 
486 	/* Return error only if no descriptors were allocated */
487 	if (i == 0) {
488 		dma_free_coherent(mdma->dma.dev,
489 			MPC_DMA_DESCRIPTORS * sizeof(struct mpc_dma_tcd),
490 								tcd, tcd_paddr);
491 		return -ENOMEM;
492 	}
493 
494 	spin_lock_irqsave(&mchan->lock, flags);
495 	mchan->tcd = tcd;
496 	mchan->tcd_paddr = tcd_paddr;
497 	list_splice_tail_init(&descs, &mchan->free);
498 	spin_unlock_irqrestore(&mchan->lock, flags);
499 
500 	/* Enable Error Interrupt */
501 	out_8(&mdma->regs->dmaseei, chan->chan_id);
502 
503 	return 0;
504 }
505 
506 /* Free channel resources */
507 static void mpc_dma_free_chan_resources(struct dma_chan *chan)
508 {
509 	struct mpc_dma *mdma = dma_chan_to_mpc_dma(chan);
510 	struct mpc_dma_chan *mchan = dma_chan_to_mpc_dma_chan(chan);
511 	struct mpc_dma_desc *mdesc, *tmp;
512 	struct mpc_dma_tcd *tcd;
513 	dma_addr_t tcd_paddr;
514 	unsigned long flags;
515 	LIST_HEAD(descs);
516 
517 	spin_lock_irqsave(&mchan->lock, flags);
518 
519 	/* Channel must be idle */
520 	BUG_ON(!list_empty(&mchan->prepared));
521 	BUG_ON(!list_empty(&mchan->queued));
522 	BUG_ON(!list_empty(&mchan->active));
523 	BUG_ON(!list_empty(&mchan->completed));
524 
525 	/* Move data */
526 	list_splice_tail_init(&mchan->free, &descs);
527 	tcd = mchan->tcd;
528 	tcd_paddr = mchan->tcd_paddr;
529 
530 	spin_unlock_irqrestore(&mchan->lock, flags);
531 
532 	/* Free DMA memory used by descriptors */
533 	dma_free_coherent(mdma->dma.dev,
534 			MPC_DMA_DESCRIPTORS * sizeof(struct mpc_dma_tcd),
535 								tcd, tcd_paddr);
536 
537 	/* Free descriptors */
538 	list_for_each_entry_safe(mdesc, tmp, &descs, node)
539 		kfree(mdesc);
540 
541 	/* Disable Error Interrupt */
542 	out_8(&mdma->regs->dmaceei, chan->chan_id);
543 }
544 
545 /* Send all pending descriptor to hardware */
546 static void mpc_dma_issue_pending(struct dma_chan *chan)
547 {
548 	/*
549 	 * We are posting descriptors to the hardware as soon as
550 	 * they are ready, so this function does nothing.
551 	 */
552 }
553 
554 /* Check request completion status */
555 static enum dma_status
556 mpc_dma_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
557 	       struct dma_tx_state *txstate)
558 {
559 	struct mpc_dma_chan *mchan = dma_chan_to_mpc_dma_chan(chan);
560 	enum dma_status ret;
561 	unsigned long flags;
562 
563 	spin_lock_irqsave(&mchan->lock, flags);
564 	ret = dma_cookie_status(chan, cookie, txstate);
565 	spin_unlock_irqrestore(&mchan->lock, flags);
566 
567 	return ret;
568 }
569 
570 /* Prepare descriptor for memory to memory copy */
571 static struct dma_async_tx_descriptor *
572 mpc_dma_prep_memcpy(struct dma_chan *chan, dma_addr_t dst, dma_addr_t src,
573 					size_t len, unsigned long flags)
574 {
575 	struct mpc_dma *mdma = dma_chan_to_mpc_dma(chan);
576 	struct mpc_dma_chan *mchan = dma_chan_to_mpc_dma_chan(chan);
577 	struct mpc_dma_desc *mdesc = NULL;
578 	struct mpc_dma_tcd *tcd;
579 	unsigned long iflags;
580 
581 	/* Get free descriptor */
582 	spin_lock_irqsave(&mchan->lock, iflags);
583 	if (!list_empty(&mchan->free)) {
584 		mdesc = list_first_entry(&mchan->free, struct mpc_dma_desc,
585 									node);
586 		list_del(&mdesc->node);
587 	}
588 	spin_unlock_irqrestore(&mchan->lock, iflags);
589 
590 	if (!mdesc) {
591 		/* try to free completed descriptors */
592 		mpc_dma_process_completed(mdma);
593 		return NULL;
594 	}
595 
596 	mdesc->error = 0;
597 	tcd = mdesc->tcd;
598 
599 	/* Prepare Transfer Control Descriptor for this transaction */
600 	memset(tcd, 0, sizeof(struct mpc_dma_tcd));
601 
602 	if (IS_ALIGNED(src | dst | len, 32)) {
603 		tcd->ssize = MPC_DMA_TSIZE_32;
604 		tcd->dsize = MPC_DMA_TSIZE_32;
605 		tcd->soff = 32;
606 		tcd->doff = 32;
607 	} else if (!mdma->is_mpc8308 && IS_ALIGNED(src | dst | len, 16)) {
608 		/* MPC8308 doesn't support 16 byte transfers */
609 		tcd->ssize = MPC_DMA_TSIZE_16;
610 		tcd->dsize = MPC_DMA_TSIZE_16;
611 		tcd->soff = 16;
612 		tcd->doff = 16;
613 	} else if (IS_ALIGNED(src | dst | len, 4)) {
614 		tcd->ssize = MPC_DMA_TSIZE_4;
615 		tcd->dsize = MPC_DMA_TSIZE_4;
616 		tcd->soff = 4;
617 		tcd->doff = 4;
618 	} else if (IS_ALIGNED(src | dst | len, 2)) {
619 		tcd->ssize = MPC_DMA_TSIZE_2;
620 		tcd->dsize = MPC_DMA_TSIZE_2;
621 		tcd->soff = 2;
622 		tcd->doff = 2;
623 	} else {
624 		tcd->ssize = MPC_DMA_TSIZE_1;
625 		tcd->dsize = MPC_DMA_TSIZE_1;
626 		tcd->soff = 1;
627 		tcd->doff = 1;
628 	}
629 
630 	tcd->saddr = src;
631 	tcd->daddr = dst;
632 	tcd->nbytes = len;
633 	tcd->biter = 1;
634 	tcd->citer = 1;
635 
636 	/* Place descriptor in prepared list */
637 	spin_lock_irqsave(&mchan->lock, iflags);
638 	list_add_tail(&mdesc->node, &mchan->prepared);
639 	spin_unlock_irqrestore(&mchan->lock, iflags);
640 
641 	return &mdesc->desc;
642 }
643 
644 static int __devinit mpc_dma_probe(struct platform_device *op)
645 {
646 	struct device_node *dn = op->dev.of_node;
647 	struct device *dev = &op->dev;
648 	struct dma_device *dma;
649 	struct mpc_dma *mdma;
650 	struct mpc_dma_chan *mchan;
651 	struct resource res;
652 	ulong regs_start, regs_size;
653 	int retval, i;
654 
655 	mdma = devm_kzalloc(dev, sizeof(struct mpc_dma), GFP_KERNEL);
656 	if (!mdma) {
657 		dev_err(dev, "Memory exhausted!\n");
658 		return -ENOMEM;
659 	}
660 
661 	mdma->irq = irq_of_parse_and_map(dn, 0);
662 	if (mdma->irq == NO_IRQ) {
663 		dev_err(dev, "Error mapping IRQ!\n");
664 		return -EINVAL;
665 	}
666 
667 	if (of_device_is_compatible(dn, "fsl,mpc8308-dma")) {
668 		mdma->is_mpc8308 = 1;
669 		mdma->irq2 = irq_of_parse_and_map(dn, 1);
670 		if (mdma->irq2 == NO_IRQ) {
671 			dev_err(dev, "Error mapping IRQ!\n");
672 			return -EINVAL;
673 		}
674 	}
675 
676 	retval = of_address_to_resource(dn, 0, &res);
677 	if (retval) {
678 		dev_err(dev, "Error parsing memory region!\n");
679 		return retval;
680 	}
681 
682 	regs_start = res.start;
683 	regs_size = resource_size(&res);
684 
685 	if (!devm_request_mem_region(dev, regs_start, regs_size, DRV_NAME)) {
686 		dev_err(dev, "Error requesting memory region!\n");
687 		return -EBUSY;
688 	}
689 
690 	mdma->regs = devm_ioremap(dev, regs_start, regs_size);
691 	if (!mdma->regs) {
692 		dev_err(dev, "Error mapping memory region!\n");
693 		return -ENOMEM;
694 	}
695 
696 	mdma->tcd = (struct mpc_dma_tcd *)((u8 *)(mdma->regs)
697 							+ MPC_DMA_TCD_OFFSET);
698 
699 	retval = devm_request_irq(dev, mdma->irq, &mpc_dma_irq, 0, DRV_NAME,
700 									mdma);
701 	if (retval) {
702 		dev_err(dev, "Error requesting IRQ!\n");
703 		return -EINVAL;
704 	}
705 
706 	if (mdma->is_mpc8308) {
707 		retval = devm_request_irq(dev, mdma->irq2, &mpc_dma_irq, 0,
708 				DRV_NAME, mdma);
709 		if (retval) {
710 			dev_err(dev, "Error requesting IRQ2!\n");
711 			return -EINVAL;
712 		}
713 	}
714 
715 	spin_lock_init(&mdma->error_status_lock);
716 
717 	dma = &mdma->dma;
718 	dma->dev = dev;
719 	if (!mdma->is_mpc8308)
720 		dma->chancnt = MPC_DMA_CHANNELS;
721 	else
722 		dma->chancnt = 16; /* MPC8308 DMA has only 16 channels */
723 	dma->device_alloc_chan_resources = mpc_dma_alloc_chan_resources;
724 	dma->device_free_chan_resources = mpc_dma_free_chan_resources;
725 	dma->device_issue_pending = mpc_dma_issue_pending;
726 	dma->device_tx_status = mpc_dma_tx_status;
727 	dma->device_prep_dma_memcpy = mpc_dma_prep_memcpy;
728 
729 	INIT_LIST_HEAD(&dma->channels);
730 	dma_cap_set(DMA_MEMCPY, dma->cap_mask);
731 
732 	for (i = 0; i < dma->chancnt; i++) {
733 		mchan = &mdma->channels[i];
734 
735 		mchan->chan.device = dma;
736 		dma_cookie_init(&mchan->chan);
737 
738 		INIT_LIST_HEAD(&mchan->free);
739 		INIT_LIST_HEAD(&mchan->prepared);
740 		INIT_LIST_HEAD(&mchan->queued);
741 		INIT_LIST_HEAD(&mchan->active);
742 		INIT_LIST_HEAD(&mchan->completed);
743 
744 		spin_lock_init(&mchan->lock);
745 		list_add_tail(&mchan->chan.device_node, &dma->channels);
746 	}
747 
748 	tasklet_init(&mdma->tasklet, mpc_dma_tasklet, (unsigned long)mdma);
749 
750 	/*
751 	 * Configure DMA Engine:
752 	 * - Dynamic clock,
753 	 * - Round-robin group arbitration,
754 	 * - Round-robin channel arbitration.
755 	 */
756 	if (!mdma->is_mpc8308) {
757 		out_be32(&mdma->regs->dmacr, MPC_DMA_DMACR_EDCG |
758 					MPC_DMA_DMACR_ERGA | MPC_DMA_DMACR_ERCA);
759 
760 		/* Disable hardware DMA requests */
761 		out_be32(&mdma->regs->dmaerqh, 0);
762 		out_be32(&mdma->regs->dmaerql, 0);
763 
764 		/* Disable error interrupts */
765 		out_be32(&mdma->regs->dmaeeih, 0);
766 		out_be32(&mdma->regs->dmaeeil, 0);
767 
768 		/* Clear interrupts status */
769 		out_be32(&mdma->regs->dmainth, 0xFFFFFFFF);
770 		out_be32(&mdma->regs->dmaintl, 0xFFFFFFFF);
771 		out_be32(&mdma->regs->dmaerrh, 0xFFFFFFFF);
772 		out_be32(&mdma->regs->dmaerrl, 0xFFFFFFFF);
773 
774 		/* Route interrupts to IPIC */
775 		out_be32(&mdma->regs->dmaihsa, 0);
776 		out_be32(&mdma->regs->dmailsa, 0);
777 	} else {
778 		/* MPC8308 has 16 channels and lacks some registers */
779 		out_be32(&mdma->regs->dmacr, MPC_DMA_DMACR_ERCA);
780 
781 		/* enable snooping */
782 		out_be32(&mdma->regs->dmagpor, MPC_DMA_DMAGPOR_SNOOP_ENABLE);
783 		/* Disable error interrupts */
784 		out_be32(&mdma->regs->dmaeeil, 0);
785 
786 		/* Clear interrupts status */
787 		out_be32(&mdma->regs->dmaintl, 0xFFFF);
788 		out_be32(&mdma->regs->dmaerrl, 0xFFFF);
789 	}
790 
791 	/* Register DMA engine */
792 	dev_set_drvdata(dev, mdma);
793 	retval = dma_async_device_register(dma);
794 	if (retval) {
795 		devm_free_irq(dev, mdma->irq, mdma);
796 		irq_dispose_mapping(mdma->irq);
797 	}
798 
799 	return retval;
800 }
801 
802 static int __devexit mpc_dma_remove(struct platform_device *op)
803 {
804 	struct device *dev = &op->dev;
805 	struct mpc_dma *mdma = dev_get_drvdata(dev);
806 
807 	dma_async_device_unregister(&mdma->dma);
808 	devm_free_irq(dev, mdma->irq, mdma);
809 	irq_dispose_mapping(mdma->irq);
810 
811 	return 0;
812 }
813 
814 static struct of_device_id mpc_dma_match[] = {
815 	{ .compatible = "fsl,mpc5121-dma", },
816 	{},
817 };
818 
819 static struct platform_driver mpc_dma_driver = {
820 	.probe		= mpc_dma_probe,
821 	.remove		= __devexit_p(mpc_dma_remove),
822 	.driver = {
823 		.name = DRV_NAME,
824 		.owner = THIS_MODULE,
825 		.of_match_table	= mpc_dma_match,
826 	},
827 };
828 
829 module_platform_driver(mpc_dma_driver);
830 
831 MODULE_LICENSE("GPL");
832 MODULE_AUTHOR("Piotr Ziecik <kosmo@semihalf.com>");
833