xref: /openbmc/linux/drivers/dma/mxs-dma.c (revision 1ab142d4)
1 /*
2  * Copyright 2011 Freescale Semiconductor, Inc. All Rights Reserved.
3  *
4  * Refer to drivers/dma/imx-sdma.c
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 
11 #include <linux/init.h>
12 #include <linux/types.h>
13 #include <linux/mm.h>
14 #include <linux/interrupt.h>
15 #include <linux/clk.h>
16 #include <linux/wait.h>
17 #include <linux/sched.h>
18 #include <linux/semaphore.h>
19 #include <linux/device.h>
20 #include <linux/dma-mapping.h>
21 #include <linux/slab.h>
22 #include <linux/platform_device.h>
23 #include <linux/dmaengine.h>
24 #include <linux/delay.h>
25 
26 #include <asm/irq.h>
27 #include <mach/mxs.h>
28 #include <mach/dma.h>
29 #include <mach/common.h>
30 
31 /*
32  * NOTE: The term "PIO" throughout the mxs-dma implementation means
33  * PIO mode of mxs apbh-dma and apbx-dma.  With this working mode,
34  * dma can program the controller registers of peripheral devices.
35  */
36 
37 #define MXS_DMA_APBH		0
38 #define MXS_DMA_APBX		1
39 #define dma_is_apbh()		(mxs_dma->dev_id == MXS_DMA_APBH)
40 
41 #define APBH_VERSION_LATEST	3
42 #define apbh_is_old()		(mxs_dma->version < APBH_VERSION_LATEST)
43 
44 #define HW_APBHX_CTRL0				0x000
45 #define BM_APBH_CTRL0_APB_BURST8_EN		(1 << 29)
46 #define BM_APBH_CTRL0_APB_BURST_EN		(1 << 28)
47 #define BP_APBH_CTRL0_RESET_CHANNEL		16
48 #define HW_APBHX_CTRL1				0x010
49 #define HW_APBHX_CTRL2				0x020
50 #define HW_APBHX_CHANNEL_CTRL			0x030
51 #define BP_APBHX_CHANNEL_CTRL_RESET_CHANNEL	16
52 #define HW_APBH_VERSION				(cpu_is_mx23() ? 0x3f0 : 0x800)
53 #define HW_APBX_VERSION				0x800
54 #define BP_APBHX_VERSION_MAJOR			24
55 #define HW_APBHX_CHn_NXTCMDAR(n) \
56 	(((dma_is_apbh() && apbh_is_old()) ? 0x050 : 0x110) + (n) * 0x70)
57 #define HW_APBHX_CHn_SEMA(n) \
58 	(((dma_is_apbh() && apbh_is_old()) ? 0x080 : 0x140) + (n) * 0x70)
59 
60 /*
61  * ccw bits definitions
62  *
63  * COMMAND:		0..1	(2)
64  * CHAIN:		2	(1)
65  * IRQ:			3	(1)
66  * NAND_LOCK:		4	(1) - not implemented
67  * NAND_WAIT4READY:	5	(1) - not implemented
68  * DEC_SEM:		6	(1)
69  * WAIT4END:		7	(1)
70  * HALT_ON_TERMINATE:	8	(1)
71  * TERMINATE_FLUSH:	9	(1)
72  * RESERVED:		10..11	(2)
73  * PIO_NUM:		12..15	(4)
74  */
75 #define BP_CCW_COMMAND		0
76 #define BM_CCW_COMMAND		(3 << 0)
77 #define CCW_CHAIN		(1 << 2)
78 #define CCW_IRQ			(1 << 3)
79 #define CCW_DEC_SEM		(1 << 6)
80 #define CCW_WAIT4END		(1 << 7)
81 #define CCW_HALT_ON_TERM	(1 << 8)
82 #define CCW_TERM_FLUSH		(1 << 9)
83 #define BP_CCW_PIO_NUM		12
84 #define BM_CCW_PIO_NUM		(0xf << 12)
85 
86 #define BF_CCW(value, field)	(((value) << BP_CCW_##field) & BM_CCW_##field)
87 
88 #define MXS_DMA_CMD_NO_XFER	0
89 #define MXS_DMA_CMD_WRITE	1
90 #define MXS_DMA_CMD_READ	2
91 #define MXS_DMA_CMD_DMA_SENSE	3	/* not implemented */
92 
93 struct mxs_dma_ccw {
94 	u32		next;
95 	u16		bits;
96 	u16		xfer_bytes;
97 #define MAX_XFER_BYTES	0xff00
98 	u32		bufaddr;
99 #define MXS_PIO_WORDS	16
100 	u32		pio_words[MXS_PIO_WORDS];
101 };
102 
103 #define NUM_CCW	(int)(PAGE_SIZE / sizeof(struct mxs_dma_ccw))
104 
105 struct mxs_dma_chan {
106 	struct mxs_dma_engine		*mxs_dma;
107 	struct dma_chan			chan;
108 	struct dma_async_tx_descriptor	desc;
109 	struct tasklet_struct		tasklet;
110 	int				chan_irq;
111 	struct mxs_dma_ccw		*ccw;
112 	dma_addr_t			ccw_phys;
113 	int				desc_count;
114 	dma_cookie_t			last_completed;
115 	enum dma_status			status;
116 	unsigned int			flags;
117 #define MXS_DMA_SG_LOOP			(1 << 0)
118 };
119 
120 #define MXS_DMA_CHANNELS		16
121 #define MXS_DMA_CHANNELS_MASK		0xffff
122 
123 struct mxs_dma_engine {
124 	int				dev_id;
125 	unsigned int			version;
126 	void __iomem			*base;
127 	struct clk			*clk;
128 	struct dma_device		dma_device;
129 	struct device_dma_parameters	dma_parms;
130 	struct mxs_dma_chan		mxs_chans[MXS_DMA_CHANNELS];
131 };
132 
133 static void mxs_dma_reset_chan(struct mxs_dma_chan *mxs_chan)
134 {
135 	struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;
136 	int chan_id = mxs_chan->chan.chan_id;
137 
138 	if (dma_is_apbh() && apbh_is_old())
139 		writel(1 << (chan_id + BP_APBH_CTRL0_RESET_CHANNEL),
140 			mxs_dma->base + HW_APBHX_CTRL0 + MXS_SET_ADDR);
141 	else
142 		writel(1 << (chan_id + BP_APBHX_CHANNEL_CTRL_RESET_CHANNEL),
143 			mxs_dma->base + HW_APBHX_CHANNEL_CTRL + MXS_SET_ADDR);
144 }
145 
146 static void mxs_dma_enable_chan(struct mxs_dma_chan *mxs_chan)
147 {
148 	struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;
149 	int chan_id = mxs_chan->chan.chan_id;
150 
151 	/* set cmd_addr up */
152 	writel(mxs_chan->ccw_phys,
153 		mxs_dma->base + HW_APBHX_CHn_NXTCMDAR(chan_id));
154 
155 	/* write 1 to SEMA to kick off the channel */
156 	writel(1, mxs_dma->base + HW_APBHX_CHn_SEMA(chan_id));
157 }
158 
159 static void mxs_dma_disable_chan(struct mxs_dma_chan *mxs_chan)
160 {
161 	mxs_chan->status = DMA_SUCCESS;
162 }
163 
164 static void mxs_dma_pause_chan(struct mxs_dma_chan *mxs_chan)
165 {
166 	struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;
167 	int chan_id = mxs_chan->chan.chan_id;
168 
169 	/* freeze the channel */
170 	if (dma_is_apbh() && apbh_is_old())
171 		writel(1 << chan_id,
172 			mxs_dma->base + HW_APBHX_CTRL0 + MXS_SET_ADDR);
173 	else
174 		writel(1 << chan_id,
175 			mxs_dma->base + HW_APBHX_CHANNEL_CTRL + MXS_SET_ADDR);
176 
177 	mxs_chan->status = DMA_PAUSED;
178 }
179 
180 static void mxs_dma_resume_chan(struct mxs_dma_chan *mxs_chan)
181 {
182 	struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;
183 	int chan_id = mxs_chan->chan.chan_id;
184 
185 	/* unfreeze the channel */
186 	if (dma_is_apbh() && apbh_is_old())
187 		writel(1 << chan_id,
188 			mxs_dma->base + HW_APBHX_CTRL0 + MXS_CLR_ADDR);
189 	else
190 		writel(1 << chan_id,
191 			mxs_dma->base + HW_APBHX_CHANNEL_CTRL + MXS_CLR_ADDR);
192 
193 	mxs_chan->status = DMA_IN_PROGRESS;
194 }
195 
196 static dma_cookie_t mxs_dma_assign_cookie(struct mxs_dma_chan *mxs_chan)
197 {
198 	dma_cookie_t cookie = mxs_chan->chan.cookie;
199 
200 	if (++cookie < 0)
201 		cookie = 1;
202 
203 	mxs_chan->chan.cookie = cookie;
204 	mxs_chan->desc.cookie = cookie;
205 
206 	return cookie;
207 }
208 
209 static struct mxs_dma_chan *to_mxs_dma_chan(struct dma_chan *chan)
210 {
211 	return container_of(chan, struct mxs_dma_chan, chan);
212 }
213 
214 static dma_cookie_t mxs_dma_tx_submit(struct dma_async_tx_descriptor *tx)
215 {
216 	struct mxs_dma_chan *mxs_chan = to_mxs_dma_chan(tx->chan);
217 
218 	mxs_dma_enable_chan(mxs_chan);
219 
220 	return mxs_dma_assign_cookie(mxs_chan);
221 }
222 
223 static void mxs_dma_tasklet(unsigned long data)
224 {
225 	struct mxs_dma_chan *mxs_chan = (struct mxs_dma_chan *) data;
226 
227 	if (mxs_chan->desc.callback)
228 		mxs_chan->desc.callback(mxs_chan->desc.callback_param);
229 }
230 
231 static irqreturn_t mxs_dma_int_handler(int irq, void *dev_id)
232 {
233 	struct mxs_dma_engine *mxs_dma = dev_id;
234 	u32 stat1, stat2;
235 
236 	/* completion status */
237 	stat1 = readl(mxs_dma->base + HW_APBHX_CTRL1);
238 	stat1 &= MXS_DMA_CHANNELS_MASK;
239 	writel(stat1, mxs_dma->base + HW_APBHX_CTRL1 + MXS_CLR_ADDR);
240 
241 	/* error status */
242 	stat2 = readl(mxs_dma->base + HW_APBHX_CTRL2);
243 	writel(stat2, mxs_dma->base + HW_APBHX_CTRL2 + MXS_CLR_ADDR);
244 
245 	/*
246 	 * When both completion and error of termination bits set at the
247 	 * same time, we do not take it as an error.  IOW, it only becomes
248 	 * an error we need to handle here in case of either it's (1) a bus
249 	 * error or (2) a termination error with no completion.
250 	 */
251 	stat2 = ((stat2 >> MXS_DMA_CHANNELS) & stat2) | /* (1) */
252 		(~(stat2 >> MXS_DMA_CHANNELS) & stat2 & ~stat1); /* (2) */
253 
254 	/* combine error and completion status for checking */
255 	stat1 = (stat2 << MXS_DMA_CHANNELS) | stat1;
256 	while (stat1) {
257 		int channel = fls(stat1) - 1;
258 		struct mxs_dma_chan *mxs_chan =
259 			&mxs_dma->mxs_chans[channel % MXS_DMA_CHANNELS];
260 
261 		if (channel >= MXS_DMA_CHANNELS) {
262 			dev_dbg(mxs_dma->dma_device.dev,
263 				"%s: error in channel %d\n", __func__,
264 				channel - MXS_DMA_CHANNELS);
265 			mxs_chan->status = DMA_ERROR;
266 			mxs_dma_reset_chan(mxs_chan);
267 		} else {
268 			if (mxs_chan->flags & MXS_DMA_SG_LOOP)
269 				mxs_chan->status = DMA_IN_PROGRESS;
270 			else
271 				mxs_chan->status = DMA_SUCCESS;
272 		}
273 
274 		stat1 &= ~(1 << channel);
275 
276 		if (mxs_chan->status == DMA_SUCCESS)
277 			mxs_chan->last_completed = mxs_chan->desc.cookie;
278 
279 		/* schedule tasklet on this channel */
280 		tasklet_schedule(&mxs_chan->tasklet);
281 	}
282 
283 	return IRQ_HANDLED;
284 }
285 
286 static int mxs_dma_alloc_chan_resources(struct dma_chan *chan)
287 {
288 	struct mxs_dma_chan *mxs_chan = to_mxs_dma_chan(chan);
289 	struct mxs_dma_data *data = chan->private;
290 	struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;
291 	int ret;
292 
293 	if (!data)
294 		return -EINVAL;
295 
296 	mxs_chan->chan_irq = data->chan_irq;
297 
298 	mxs_chan->ccw = dma_alloc_coherent(mxs_dma->dma_device.dev, PAGE_SIZE,
299 				&mxs_chan->ccw_phys, GFP_KERNEL);
300 	if (!mxs_chan->ccw) {
301 		ret = -ENOMEM;
302 		goto err_alloc;
303 	}
304 
305 	memset(mxs_chan->ccw, 0, PAGE_SIZE);
306 
307 	if (mxs_chan->chan_irq != NO_IRQ) {
308 		ret = request_irq(mxs_chan->chan_irq, mxs_dma_int_handler,
309 					0, "mxs-dma", mxs_dma);
310 		if (ret)
311 			goto err_irq;
312 	}
313 
314 	ret = clk_prepare_enable(mxs_dma->clk);
315 	if (ret)
316 		goto err_clk;
317 
318 	mxs_dma_reset_chan(mxs_chan);
319 
320 	dma_async_tx_descriptor_init(&mxs_chan->desc, chan);
321 	mxs_chan->desc.tx_submit = mxs_dma_tx_submit;
322 
323 	/* the descriptor is ready */
324 	async_tx_ack(&mxs_chan->desc);
325 
326 	return 0;
327 
328 err_clk:
329 	free_irq(mxs_chan->chan_irq, mxs_dma);
330 err_irq:
331 	dma_free_coherent(mxs_dma->dma_device.dev, PAGE_SIZE,
332 			mxs_chan->ccw, mxs_chan->ccw_phys);
333 err_alloc:
334 	return ret;
335 }
336 
337 static void mxs_dma_free_chan_resources(struct dma_chan *chan)
338 {
339 	struct mxs_dma_chan *mxs_chan = to_mxs_dma_chan(chan);
340 	struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;
341 
342 	mxs_dma_disable_chan(mxs_chan);
343 
344 	free_irq(mxs_chan->chan_irq, mxs_dma);
345 
346 	dma_free_coherent(mxs_dma->dma_device.dev, PAGE_SIZE,
347 			mxs_chan->ccw, mxs_chan->ccw_phys);
348 
349 	clk_disable_unprepare(mxs_dma->clk);
350 }
351 
352 static struct dma_async_tx_descriptor *mxs_dma_prep_slave_sg(
353 		struct dma_chan *chan, struct scatterlist *sgl,
354 		unsigned int sg_len, enum dma_transfer_direction direction,
355 		unsigned long append)
356 {
357 	struct mxs_dma_chan *mxs_chan = to_mxs_dma_chan(chan);
358 	struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;
359 	struct mxs_dma_ccw *ccw;
360 	struct scatterlist *sg;
361 	int i, j;
362 	u32 *pio;
363 	int idx = append ? mxs_chan->desc_count : 0;
364 
365 	if (mxs_chan->status == DMA_IN_PROGRESS && !append)
366 		return NULL;
367 
368 	if (sg_len + (append ? idx : 0) > NUM_CCW) {
369 		dev_err(mxs_dma->dma_device.dev,
370 				"maximum number of sg exceeded: %d > %d\n",
371 				sg_len, NUM_CCW);
372 		goto err_out;
373 	}
374 
375 	mxs_chan->status = DMA_IN_PROGRESS;
376 	mxs_chan->flags = 0;
377 
378 	/*
379 	 * If the sg is prepared with append flag set, the sg
380 	 * will be appended to the last prepared sg.
381 	 */
382 	if (append) {
383 		BUG_ON(idx < 1);
384 		ccw = &mxs_chan->ccw[idx - 1];
385 		ccw->next = mxs_chan->ccw_phys + sizeof(*ccw) * idx;
386 		ccw->bits |= CCW_CHAIN;
387 		ccw->bits &= ~CCW_IRQ;
388 		ccw->bits &= ~CCW_DEC_SEM;
389 		ccw->bits &= ~CCW_WAIT4END;
390 	} else {
391 		idx = 0;
392 	}
393 
394 	if (direction == DMA_TRANS_NONE) {
395 		ccw = &mxs_chan->ccw[idx++];
396 		pio = (u32 *) sgl;
397 
398 		for (j = 0; j < sg_len;)
399 			ccw->pio_words[j++] = *pio++;
400 
401 		ccw->bits = 0;
402 		ccw->bits |= CCW_IRQ;
403 		ccw->bits |= CCW_DEC_SEM;
404 		ccw->bits |= CCW_WAIT4END;
405 		ccw->bits |= CCW_HALT_ON_TERM;
406 		ccw->bits |= CCW_TERM_FLUSH;
407 		ccw->bits |= BF_CCW(sg_len, PIO_NUM);
408 		ccw->bits |= BF_CCW(MXS_DMA_CMD_NO_XFER, COMMAND);
409 	} else {
410 		for_each_sg(sgl, sg, sg_len, i) {
411 			if (sg->length > MAX_XFER_BYTES) {
412 				dev_err(mxs_dma->dma_device.dev, "maximum bytes for sg entry exceeded: %d > %d\n",
413 						sg->length, MAX_XFER_BYTES);
414 				goto err_out;
415 			}
416 
417 			ccw = &mxs_chan->ccw[idx++];
418 
419 			ccw->next = mxs_chan->ccw_phys + sizeof(*ccw) * idx;
420 			ccw->bufaddr = sg->dma_address;
421 			ccw->xfer_bytes = sg->length;
422 
423 			ccw->bits = 0;
424 			ccw->bits |= CCW_CHAIN;
425 			ccw->bits |= CCW_HALT_ON_TERM;
426 			ccw->bits |= CCW_TERM_FLUSH;
427 			ccw->bits |= BF_CCW(direction == DMA_DEV_TO_MEM ?
428 					MXS_DMA_CMD_WRITE : MXS_DMA_CMD_READ,
429 					COMMAND);
430 
431 			if (i + 1 == sg_len) {
432 				ccw->bits &= ~CCW_CHAIN;
433 				ccw->bits |= CCW_IRQ;
434 				ccw->bits |= CCW_DEC_SEM;
435 				ccw->bits |= CCW_WAIT4END;
436 			}
437 		}
438 	}
439 	mxs_chan->desc_count = idx;
440 
441 	return &mxs_chan->desc;
442 
443 err_out:
444 	mxs_chan->status = DMA_ERROR;
445 	return NULL;
446 }
447 
448 static struct dma_async_tx_descriptor *mxs_dma_prep_dma_cyclic(
449 		struct dma_chan *chan, dma_addr_t dma_addr, size_t buf_len,
450 		size_t period_len, enum dma_transfer_direction direction)
451 {
452 	struct mxs_dma_chan *mxs_chan = to_mxs_dma_chan(chan);
453 	struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;
454 	int num_periods = buf_len / period_len;
455 	int i = 0, buf = 0;
456 
457 	if (mxs_chan->status == DMA_IN_PROGRESS)
458 		return NULL;
459 
460 	mxs_chan->status = DMA_IN_PROGRESS;
461 	mxs_chan->flags |= MXS_DMA_SG_LOOP;
462 
463 	if (num_periods > NUM_CCW) {
464 		dev_err(mxs_dma->dma_device.dev,
465 				"maximum number of sg exceeded: %d > %d\n",
466 				num_periods, NUM_CCW);
467 		goto err_out;
468 	}
469 
470 	if (period_len > MAX_XFER_BYTES) {
471 		dev_err(mxs_dma->dma_device.dev,
472 				"maximum period size exceeded: %d > %d\n",
473 				period_len, MAX_XFER_BYTES);
474 		goto err_out;
475 	}
476 
477 	while (buf < buf_len) {
478 		struct mxs_dma_ccw *ccw = &mxs_chan->ccw[i];
479 
480 		if (i + 1 == num_periods)
481 			ccw->next = mxs_chan->ccw_phys;
482 		else
483 			ccw->next = mxs_chan->ccw_phys + sizeof(*ccw) * (i + 1);
484 
485 		ccw->bufaddr = dma_addr;
486 		ccw->xfer_bytes = period_len;
487 
488 		ccw->bits = 0;
489 		ccw->bits |= CCW_CHAIN;
490 		ccw->bits |= CCW_IRQ;
491 		ccw->bits |= CCW_HALT_ON_TERM;
492 		ccw->bits |= CCW_TERM_FLUSH;
493 		ccw->bits |= BF_CCW(direction == DMA_DEV_TO_MEM ?
494 				MXS_DMA_CMD_WRITE : MXS_DMA_CMD_READ, COMMAND);
495 
496 		dma_addr += period_len;
497 		buf += period_len;
498 
499 		i++;
500 	}
501 	mxs_chan->desc_count = i;
502 
503 	return &mxs_chan->desc;
504 
505 err_out:
506 	mxs_chan->status = DMA_ERROR;
507 	return NULL;
508 }
509 
510 static int mxs_dma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
511 		unsigned long arg)
512 {
513 	struct mxs_dma_chan *mxs_chan = to_mxs_dma_chan(chan);
514 	int ret = 0;
515 
516 	switch (cmd) {
517 	case DMA_TERMINATE_ALL:
518 		mxs_dma_reset_chan(mxs_chan);
519 		mxs_dma_disable_chan(mxs_chan);
520 		break;
521 	case DMA_PAUSE:
522 		mxs_dma_pause_chan(mxs_chan);
523 		break;
524 	case DMA_RESUME:
525 		mxs_dma_resume_chan(mxs_chan);
526 		break;
527 	default:
528 		ret = -ENOSYS;
529 	}
530 
531 	return ret;
532 }
533 
534 static enum dma_status mxs_dma_tx_status(struct dma_chan *chan,
535 			dma_cookie_t cookie, struct dma_tx_state *txstate)
536 {
537 	struct mxs_dma_chan *mxs_chan = to_mxs_dma_chan(chan);
538 	dma_cookie_t last_used;
539 
540 	last_used = chan->cookie;
541 	dma_set_tx_state(txstate, mxs_chan->last_completed, last_used, 0);
542 
543 	return mxs_chan->status;
544 }
545 
546 static void mxs_dma_issue_pending(struct dma_chan *chan)
547 {
548 	/*
549 	 * Nothing to do. We only have a single descriptor.
550 	 */
551 }
552 
553 static int __init mxs_dma_init(struct mxs_dma_engine *mxs_dma)
554 {
555 	int ret;
556 
557 	ret = clk_prepare_enable(mxs_dma->clk);
558 	if (ret)
559 		return ret;
560 
561 	ret = mxs_reset_block(mxs_dma->base);
562 	if (ret)
563 		goto err_out;
564 
565 	/* only major version matters */
566 	mxs_dma->version = readl(mxs_dma->base +
567 				((mxs_dma->dev_id == MXS_DMA_APBX) ?
568 				HW_APBX_VERSION : HW_APBH_VERSION)) >>
569 				BP_APBHX_VERSION_MAJOR;
570 
571 	/* enable apbh burst */
572 	if (dma_is_apbh()) {
573 		writel(BM_APBH_CTRL0_APB_BURST_EN,
574 			mxs_dma->base + HW_APBHX_CTRL0 + MXS_SET_ADDR);
575 		writel(BM_APBH_CTRL0_APB_BURST8_EN,
576 			mxs_dma->base + HW_APBHX_CTRL0 + MXS_SET_ADDR);
577 	}
578 
579 	/* enable irq for all the channels */
580 	writel(MXS_DMA_CHANNELS_MASK << MXS_DMA_CHANNELS,
581 		mxs_dma->base + HW_APBHX_CTRL1 + MXS_SET_ADDR);
582 
583 err_out:
584 	clk_disable_unprepare(mxs_dma->clk);
585 	return ret;
586 }
587 
588 static int __init mxs_dma_probe(struct platform_device *pdev)
589 {
590 	const struct platform_device_id *id_entry =
591 				platform_get_device_id(pdev);
592 	struct mxs_dma_engine *mxs_dma;
593 	struct resource *iores;
594 	int ret, i;
595 
596 	mxs_dma = kzalloc(sizeof(*mxs_dma), GFP_KERNEL);
597 	if (!mxs_dma)
598 		return -ENOMEM;
599 
600 	mxs_dma->dev_id = id_entry->driver_data;
601 
602 	iores = platform_get_resource(pdev, IORESOURCE_MEM, 0);
603 
604 	if (!request_mem_region(iores->start, resource_size(iores),
605 				pdev->name)) {
606 		ret = -EBUSY;
607 		goto err_request_region;
608 	}
609 
610 	mxs_dma->base = ioremap(iores->start, resource_size(iores));
611 	if (!mxs_dma->base) {
612 		ret = -ENOMEM;
613 		goto err_ioremap;
614 	}
615 
616 	mxs_dma->clk = clk_get(&pdev->dev, NULL);
617 	if (IS_ERR(mxs_dma->clk)) {
618 		ret = PTR_ERR(mxs_dma->clk);
619 		goto err_clk;
620 	}
621 
622 	dma_cap_set(DMA_SLAVE, mxs_dma->dma_device.cap_mask);
623 	dma_cap_set(DMA_CYCLIC, mxs_dma->dma_device.cap_mask);
624 
625 	INIT_LIST_HEAD(&mxs_dma->dma_device.channels);
626 
627 	/* Initialize channel parameters */
628 	for (i = 0; i < MXS_DMA_CHANNELS; i++) {
629 		struct mxs_dma_chan *mxs_chan = &mxs_dma->mxs_chans[i];
630 
631 		mxs_chan->mxs_dma = mxs_dma;
632 		mxs_chan->chan.device = &mxs_dma->dma_device;
633 
634 		tasklet_init(&mxs_chan->tasklet, mxs_dma_tasklet,
635 			     (unsigned long) mxs_chan);
636 
637 
638 		/* Add the channel to mxs_chan list */
639 		list_add_tail(&mxs_chan->chan.device_node,
640 			&mxs_dma->dma_device.channels);
641 	}
642 
643 	ret = mxs_dma_init(mxs_dma);
644 	if (ret)
645 		goto err_init;
646 
647 	mxs_dma->dma_device.dev = &pdev->dev;
648 
649 	/* mxs_dma gets 65535 bytes maximum sg size */
650 	mxs_dma->dma_device.dev->dma_parms = &mxs_dma->dma_parms;
651 	dma_set_max_seg_size(mxs_dma->dma_device.dev, MAX_XFER_BYTES);
652 
653 	mxs_dma->dma_device.device_alloc_chan_resources = mxs_dma_alloc_chan_resources;
654 	mxs_dma->dma_device.device_free_chan_resources = mxs_dma_free_chan_resources;
655 	mxs_dma->dma_device.device_tx_status = mxs_dma_tx_status;
656 	mxs_dma->dma_device.device_prep_slave_sg = mxs_dma_prep_slave_sg;
657 	mxs_dma->dma_device.device_prep_dma_cyclic = mxs_dma_prep_dma_cyclic;
658 	mxs_dma->dma_device.device_control = mxs_dma_control;
659 	mxs_dma->dma_device.device_issue_pending = mxs_dma_issue_pending;
660 
661 	ret = dma_async_device_register(&mxs_dma->dma_device);
662 	if (ret) {
663 		dev_err(mxs_dma->dma_device.dev, "unable to register\n");
664 		goto err_init;
665 	}
666 
667 	dev_info(mxs_dma->dma_device.dev, "initialized\n");
668 
669 	return 0;
670 
671 err_init:
672 	clk_put(mxs_dma->clk);
673 err_clk:
674 	iounmap(mxs_dma->base);
675 err_ioremap:
676 	release_mem_region(iores->start, resource_size(iores));
677 err_request_region:
678 	kfree(mxs_dma);
679 	return ret;
680 }
681 
682 static struct platform_device_id mxs_dma_type[] = {
683 	{
684 		.name = "mxs-dma-apbh",
685 		.driver_data = MXS_DMA_APBH,
686 	}, {
687 		.name = "mxs-dma-apbx",
688 		.driver_data = MXS_DMA_APBX,
689 	}, {
690 		/* end of list */
691 	}
692 };
693 
694 static struct platform_driver mxs_dma_driver = {
695 	.driver		= {
696 		.name	= "mxs-dma",
697 	},
698 	.id_table	= mxs_dma_type,
699 };
700 
701 static int __init mxs_dma_module_init(void)
702 {
703 	return platform_driver_probe(&mxs_dma_driver, mxs_dma_probe);
704 }
705 subsys_initcall(mxs_dma_module_init);
706