summaryrefslogtreecommitdiffstats
path: root/drivers/mmc/host/moxart-mmc.c
blob: 006f1862444b245a8c7564c60cff9a915e13d127 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
/*
 * MOXA ART MMC host driver.
 *
 * Copyright (C) 2014 Jonas Jensen
 *
 * Jonas Jensen <jonas.jensen@gmail.com>
 *
 * Based on code from
 * Moxa Technologies Co., Ltd. <www.moxa.com>
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2.  This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/blkdev.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/mmc/host.h>
#include <linux/mmc/sd.h>
#include <linux/sched.h>
#include <linux/io.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/clk.h>
#include <linux/bitops.h>
#include <linux/of_dma.h>
#include <linux/spinlock.h>

#define REG_COMMAND		0
#define REG_ARGUMENT		4
#define REG_RESPONSE0		8
#define REG_RESPONSE1		12
#define REG_RESPONSE2		16
#define REG_RESPONSE3		20
#define REG_RESPONSE_COMMAND	24
#define REG_DATA_CONTROL	28
#define REG_DATA_TIMER		32
#define REG_DATA_LENGTH		36
#define REG_STATUS		40
#define REG_CLEAR		44
#define REG_INTERRUPT_MASK	48
#define REG_POWER_CONTROL	52
#define REG_CLOCK_CONTROL	56
#define REG_BUS_WIDTH		60
#define REG_DATA_WINDOW		64
#define REG_FEATURE		68
#define REG_REVISION		72

/* REG_COMMAND */
#define CMD_SDC_RESET		BIT(10)
#define CMD_EN			BIT(9)
#define CMD_APP_CMD		BIT(8)
#define CMD_LONG_RSP		BIT(7)
#define CMD_NEED_RSP		BIT(6)
#define CMD_IDX_MASK		0x3f

/* REG_RESPONSE_COMMAND */
#define RSP_CMD_APP		BIT(6)
#define RSP_CMD_IDX_MASK	0x3f

/* REG_DATA_CONTROL */
#define DCR_DATA_FIFO_RESET     BIT(8)
#define DCR_DATA_THRES          BIT(7)
#define DCR_DATA_EN		BIT(6)
#define DCR_DMA_EN		BIT(5)
#define DCR_DATA_WRITE		BIT(4)
#define DCR_BLK_SIZE		0x0f

/* REG_DATA_LENGTH */
#define DATA_LEN_MASK		0xffffff

/* REG_STATUS */
#define WRITE_PROT		BIT(12)
#define CARD_DETECT		BIT(11)
/* 1-10 below can be sent to either registers, interrupt or clear. */
#define CARD_CHANGE		BIT(10)
#define FIFO_ORUN		BIT(9)
#define FIFO_URUN		BIT(8)
#define DATA_END		BIT(7)
#define CMD_SENT		BIT(6)
#define DATA_CRC_OK		BIT(5)
#define RSP_CRC_OK		BIT(4)
#define DATA_TIMEOUT		BIT(3)
#define RSP_TIMEOUT		BIT(2)
#define DATA_CRC_FAIL		BIT(1)
#define RSP_CRC_FAIL		BIT(0)

#define MASK_RSP		(RSP_TIMEOUT | RSP_CRC_FAIL | \
				 RSP_CRC_OK  | CARD_DETECT  | CMD_SENT)

#define MASK_DATA		(DATA_CRC_OK   | DATA_END | \
				 DATA_CRC_FAIL | DATA_TIMEOUT)

#define MASK_INTR_PIO		(FIFO_URUN | FIFO_ORUN | CARD_CHANGE)

/* REG_POWER_CONTROL */
#define SD_POWER_ON		BIT(4)
#define SD_POWER_MASK		0x0f

/* REG_CLOCK_CONTROL */
#define CLK_HISPD		BIT(9)
#define CLK_OFF			BIT(8)
#define CLK_SD			BIT(7)
#define CLK_DIV_MASK		0x7f

/* REG_BUS_WIDTH */
#define BUS_WIDTH_8		BIT(2)
#define BUS_WIDTH_4		BIT(1)
#define BUS_WIDTH_1		BIT(0)

#define MMC_VDD_360		23
#define MIN_POWER		(MMC_VDD_360 - SD_POWER_MASK)
#define MAX_RETRIES		500000

struct moxart_host {
	spinlock_t			lock;

	void __iomem			*base;

	phys_addr_t			reg_phys;

	struct dma_chan			*dma_chan_tx;
	struct dma_chan                 *dma_chan_rx;
	struct dma_async_tx_descriptor	*tx_desc;
	struct mmc_host			*mmc;
	struct mmc_request		*mrq;
	struct scatterlist		*cur_sg;
	struct completion		dma_complete;
	struct completion		pio_complete;

	u32				num_sg;
	u32				data_remain;
	u32				data_len;
	u32				fifo_width;
	u32				timeout;
	u32				rate;

	long				sysclk;

	bool				have_dma;
	bool				is_removed;
};

static inline void moxart_init_sg(struct moxart_host *host,
				  struct mmc_data *data)
{
	host->cur_sg = data->sg;
	host->num_sg = data->sg_len;
	host->data_remain = host->cur_sg->length;

	if (host->data_remain > host->data_len)
		host->data_remain = host->data_len;
}

static inline int moxart_next_sg(struct moxart_host *host)
{
	int remain;
	struct mmc_data *data = host->mrq->cmd->data;

	host->cur_sg++;
	host->num_sg--;

	if (host->num_sg > 0) {
		host->data_remain = host->cur_sg->length;
		remain = host->data_len - data->bytes_xfered;
		if (remain > 0 && remain < host->data_remain)
			host->data_remain = remain;
	}

	return host->num_sg;
}

static int moxart_wait_for_status(struct moxart_host *host,
				  u32 mask, u32 *status)
{
	int ret = -ETIMEDOUT;
	u32 i;

	for (i = 0; i < MAX_RETRIES; i++) {
		*status = readl(host->base + REG_STATUS);
		if (!(*status & mask)) {
			udelay(5);
			continue;
		}
		writel(*status & mask, host->base + REG_CLEAR);
		ret = 0;
		break;
	}

	if (ret)
		dev_err(mmc_dev(host->mmc), "timed out waiting for status\n");

	return ret;
}


static void moxart_send_command(struct moxart_host *host,
	struct mmc_command *cmd)
{
	u32 status, cmdctrl;

	writel(RSP_TIMEOUT  | RSP_CRC_OK |
	       RSP_CRC_FAIL | CMD_SENT, host->base + REG_CLEAR);
	writel(cmd->arg, host->base + REG_ARGUMENT);

	cmdctrl = cmd->opcode & CMD_IDX_MASK;
	if (cmdctrl == SD_APP_SET_BUS_WIDTH    || cmdctrl == SD_APP_OP_COND   ||
	    cmdctrl == SD_APP_SEND_SCR         || cmdctrl == SD_APP_SD_STATUS ||
	    cmdctrl == SD_APP_SEND_NUM_WR_BLKS)
		cmdctrl |= CMD_APP_CMD;

	if (cmd->flags & MMC_RSP_PRESENT)
		cmdctrl |= CMD_NEED_RSP;

	if (cmd->flags & MMC_RSP_136)
		cmdctrl |= CMD_LONG_RSP;

	writel(cmdctrl | CMD_EN, host->base + REG_COMMAND);

	if (moxart_wait_for_status(host, MASK_RSP, &status) == -ETIMEDOUT)
		cmd->error = -ETIMEDOUT;

	if (status & RSP_TIMEOUT) {
		cmd->error = -ETIMEDOUT;
		return;
	}
	if (status & RSP_CRC_FAIL) {
		cmd->error = -EIO;
		return;
	}
	if (status & RSP_CRC_OK) {
		if (cmd->flags & MMC_RSP_136) {
			cmd->resp[3] = readl(host->base + REG_RESPONSE0);
			cmd->resp[2] = readl(host->base + REG_RESPONSE1);
			cmd->resp[1] = readl(host->base + REG_RESPONSE2);
			cmd->resp[0] = readl(host->base + REG_RESPONSE3);
		} else {
			cmd->resp[0] = readl(host->base + REG_RESPONSE0);
		}
	}
}

static void moxart_dma_complete(void *param)
{
	struct moxart_host *host = param;

	complete(&host->dma_complete);
}

static void moxart_transfer_dma(struct mmc_data *data, struct moxart_host *host)
{
	u32 len, dir_data, dir_slave;
	unsigned long dma_time;
	struct dma_async_tx_descriptor *desc = NULL;
	struct dma_chan *dma_chan;

	if (host->data_len == data->bytes_xfered)
		return;

	if (data->flags & MMC_DATA_WRITE) {
		dma_chan = host->dma_chan_tx;
		dir_data = DMA_TO_DEVICE;
		dir_slave = DMA_MEM_TO_DEV;
	} else {
		dma_chan = host->dma_chan_rx;
		dir_data = DMA_FROM_DEVICE;
		dir_slave = DMA_DEV_TO_MEM;
	}

	len = dma_map_sg(dma_chan->device->dev, data->sg,
			 data->sg_len, dir_data);

	if (len > 0) {
		desc = dmaengine_prep_slave_sg(dma_chan, data->sg,
					       len, dir_slave,
					       DMA_PREP_INTERRUPT |
					       DMA_CTRL_ACK);
	} else {
		dev_err(mmc_dev(host->mmc), "dma_map_sg returned zero length\n");
	}

	if (desc) {
		host->tx_desc = desc;
		desc->callback = moxart_dma_complete;
		desc->callback_param = host;
		dmaengine_submit(desc);
		dma_async_issue_pending(dma_chan);
	}

	data->bytes_xfered += host->data_remain;

	dma_time = wait_for_completion_interruptible_timeout(
		   &host->dma_complete, host->timeout);

	dma_unmap_sg(dma_chan->device->dev,
		     data->sg, data->sg_len,
		     dir_data);
}


static void moxart_transfer_pio(struct moxart_host *host)
{
	struct mmc_data *data = host->mrq->cmd->data;
	u32 *sgp, len = 0, remain, status;

	if (host->data_len == data->bytes_xfered)
		return;

	sgp = sg_virt(host->cur_sg);
	remain = host->data_remain;

	if (data->flags & MMC_DATA_WRITE) {
		while (remain > 0) {
			if (moxart_wait_for_status(host, FIFO_URUN, &status)
			     == -ETIMEDOUT) {
				data->error = -ETIMEDOUT;
				complete(&host->pio_complete);
				return;
			}
			for (len = 0; len < remain && len < host->fifo_width;) {
				iowrite32(*sgp, host->base + REG_DATA_WINDOW);
				sgp++;
				len += 4;
			}
			remain -= len;
		}

	} else {
		while (remain > 0) {
			if (moxart_wait_for_status(host, FIFO_ORUN, &status)
			    == -ETIMEDOUT) {
				data->error = -ETIMEDOUT;
				complete(&host->pio_complete);
				return;
			}
			for (len = 0; len < remain && len < host->fifo_width;) {
				/* SCR data must be read in big endian. */
				if (data->mrq->cmd->opcode == SD_APP_SEND_SCR)
					*sgp = ioread32be(host->base +
							  REG_DATA_WINDOW);
				else
					*sgp = ioread32(host->base +
							REG_DATA_WINDOW);
				sgp++;
				len += 4;
			}
			remain -= len;
		}
	}

	data->bytes_xfered += host->data_remain - remain;
	host->data_remain = remain;

	if (host->data_len != data->bytes_xfered)
		moxart_next_sg(host);
	else
		complete(&host->pio_complete);
}

static void moxart_prepare_data(struct moxart_host *host)
{
	struct mmc_data *data = host->mrq->cmd->data;
	u32 datactrl;
	int blksz_bits;

	if (!data)
		return;

	host->data_len = data->blocks * data->blksz;
	blksz_bits = ffs(data->blksz) - 1;
	BUG_ON(1 << blksz_bits != data->blksz);

	moxart_init_sg(host, data);

	datactrl = DCR_DATA_EN | (blksz_bits & DCR_BLK_SIZE);

	if (data->flags & MMC_DATA_WRITE)
		datactrl |= DCR_DATA_WRITE;

	if ((host->data_len > host->fifo_width) && host->have_dma)
		datactrl |= DCR_DMA_EN;

	writel(DCR_DATA_FIFO_RESET, host->base + REG_DATA_CONTROL);
	writel(MASK_DATA | FIFO_URUN | FIFO_ORUN, host->base + REG_CLEAR);
	writel(host->rate, host->base + REG_DATA_TIMER);
	writel(host->data_len, host->base + REG_DATA_LENGTH);
	writel(datactrl, host->base + REG_DATA_CONTROL);
}

static void moxart_request(struct mmc_host *mmc, struct mmc_request *mrq)
{
	struct moxart_host *host = mmc_priv(mmc);
	unsigned long pio_time, flags;
	u32 status;

	spin_lock_irqsave(&host->lock, flags);

	init_completion(&host->dma_complete);
	init_completion(&host->pio_complete);

	host->mrq = mrq;

	if (readl(host->base + REG_STATUS) & CARD_DETECT) {
		mrq->cmd->error = -ETIMEDOUT;
		goto request_done;
	}

	moxart_prepare_data(host);
	moxart_send_command(host, host->mrq->cmd);

	if (mrq->cmd->data) {
		if ((host->data_len > host->fifo_width) && host->have_dma) {

			writel(CARD_CHANGE, host->base + REG_INTERRUPT_MASK);

			spin_unlock_irqrestore(&host->lock, flags);

			moxart_transfer_dma(mrq->cmd->data, host);

			spin_lock_irqsave(&host->lock, flags);
		} else {

			writel(MASK_INTR_PIO, host->base + REG_INTERRUPT_MASK);

			spin_unlock_irqrestore(&host->lock, flags);

			/* PIO transfers start from interrupt. */
			pio_time = wait_for_completion_interruptible_timeout(
				   &host->pio_complete, host->timeout);

			spin_lock_irqsave(&host->lock, flags);
		}

		if (host->is_removed) {
			dev_err(mmc_dev(host->mmc), "card removed\n");
			mrq->cmd->error = -ETIMEDOUT;
			goto request_done;
		}

		if (moxart_wait_for_status(host, MASK_DATA, &status)
		    == -ETIMEDOUT) {
			mrq->cmd->data->error = -ETIMEDOUT;
			goto request_done;
		}

		if (status & DATA_CRC_FAIL)
			mrq->cmd->data->error = -ETIMEDOUT;

		if (mrq->cmd->data->stop)
			moxart_send_command(host, mrq->cmd->data->stop);
	}

request_done:
	spin_unlock_irqrestore(&host->lock, flags);
	mmc_request_done(host->mmc, mrq);
}

static irqreturn_t moxart_irq(int irq, void *devid)
{
	struct moxart_host *host = (struct moxart_host *)devid;
	u32 status;
	unsigned long flags;

	spin_lock_irqsave(&host->lock, flags);

	status = readl(host->base + REG_STATUS);
	if (status & CARD_CHANGE) {
		host->is_removed = status & CARD_DETECT;
		if (host->is_removed && host->have_dma) {
			dmaengine_terminate_all(host->dma_chan_tx);
			dmaengine_terminate_all(host->dma_chan_rx);
		}
		host->mrq = NULL;
		writel(MASK_INTR_PIO, host->base + REG_CLEAR);
		writel(CARD_CHANGE, host->base + REG_INTERRUPT_MASK);
		mmc_detect_change(host->mmc, 0);
	}
	if (status & (FIFO_ORUN | FIFO_URUN) && host->mrq)
		moxart_transfer_pio(host);

	spin_unlock_irqrestore(&host->lock, flags);

	return IRQ_HANDLED;
}

static void moxart_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
{
	struct moxart_host *host = mmc_priv(mmc);
	unsigned long flags;
	u8 power, div;
	u32 ctrl;

	spin_lock_irqsave(&host->lock, flags);

	if (ios->clock) {
		for (div = 0; div < CLK_DIV_MASK; ++div) {
			if (ios->clock >= host->sysclk / (2 * (div + 1)))
				break;
		}
		ctrl = CLK_SD | div;
		host->rate = host->sysclk / (2 * (div + 1));
		if (host->rate > host->sysclk)
			ctrl |= CLK_HISPD;
		writel(ctrl, host->base + REG_CLOCK_CONTROL);
	}

	if (ios->power_mode == MMC_POWER_OFF) {
		writel(readl(host->base + REG_POWER_CONTROL) & ~SD_POWER_ON,
		       host->base + REG_POWER_CONTROL);
	} else {
		if (ios->vdd < MIN_POWER)
			power = 0;
		else
			power = ios->vdd - MIN_POWER;

		writel(SD_POWER_ON | (u32) power,
		       host->base + REG_POWER_CONTROL);
	}

	switch (ios->bus_width) {
	case MMC_BUS_WIDTH_4:
		writel(BUS_WIDTH_4, host->base + REG_BUS_WIDTH);
		break;
	case MMC_BUS_WIDTH_8:
		writel(BUS_WIDTH_8, host->base + REG_BUS_WIDTH);
		break;
	default:
		writel(BUS_WIDTH_1, host->base + REG_BUS_WIDTH);
		break;
	}

	spin_unlock_irqrestore(&host->lock, flags);
}


static int moxart_get_ro(struct mmc_host *mmc)
{
	struct moxart_host *host = mmc_priv(mmc);

	return !!(readl(host->base + REG_STATUS) & WRITE_PROT);
}

static struct mmc_host_ops moxart_ops = {
	.request = moxart_request,
	.set_ios = moxart_set_ios,
	.get_ro = moxart_get_ro,
};

static int moxart_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct device_node *node = dev->of_node;
	struct resource res_mmc;
	struct mmc_host *mmc;
	struct moxart_host *host = NULL;
	struct dma_slave_config cfg;
	struct clk *clk;
	void __iomem *reg_mmc;
	int irq, ret;
	u32 i;

	mmc = mmc_alloc_host(sizeof(struct moxart_host), dev);
	if (!mmc) {
		dev_err(dev, "mmc_alloc_host failed\n");
		ret = -ENOMEM;
		goto out;
	}

	ret = of_address_to_resource(node, 0, &res_mmc);
	if (ret) {
		dev_err(dev, "of_address_to_resource failed\n");
		goto out;
	}

	irq = irq_of_parse_and_map(node, 0);
	if (irq <= 0) {
		dev_err(dev, "irq_of_parse_and_map failed\n");
		ret = -EINVAL;
		goto out;
	}

	clk = devm_clk_get(dev, NULL);
	if (IS_ERR(clk)) {
		ret = PTR_ERR(clk);
		goto out;
	}

	reg_mmc = devm_ioremap_resource(dev, &res_mmc);
	if (IS_ERR(reg_mmc)) {
		ret = PTR_ERR(reg_mmc);
		goto out;
	}

	ret = mmc_of_parse(mmc);
	if (ret)
		goto out;

	host = mmc_priv(mmc);
	host->mmc = mmc;
	host->base = reg_mmc;
	host->reg_phys = res_mmc.start;
	host->timeout = msecs_to_jiffies(1000);
	host->sysclk = clk_get_rate(clk);
	host->fifo_width = readl(host->base + REG_FEATURE) << 2;
	host->dma_chan_tx = dma_request_slave_channel_reason(dev, "tx");
	host->dma_chan_rx = dma_request_slave_channel_reason(dev, "rx");

	spin_lock_init(&host->lock);

	mmc->ops = &moxart_ops;
	mmc->f_max = DIV_ROUND_CLOSEST(host->sysclk, 2);
	mmc->f_min = DIV_ROUND_CLOSEST(host->sysclk, CLK_DIV_MASK * 2);
	mmc->ocr_avail = 0xffff00;	/* Support 2.0v - 3.6v power. */

	if (IS_ERR(host->dma_chan_tx) || IS_ERR(host->dma_chan_rx)) {
		if (PTR_ERR(host->dma_chan_tx) == -EPROBE_DEFER ||
		    PTR_ERR(host->dma_chan_rx) == -EPROBE_DEFER) {
			ret = -EPROBE_DEFER;
			goto out;
		}
		dev_dbg(dev, "PIO mode transfer enabled\n");
		host->have_dma = false;
	} else {
		dev_dbg(dev, "DMA channels found (%p,%p)\n",
			 host->dma_chan_tx, host->dma_chan_rx);
		host->have_dma = true;

		cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
		cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;

		cfg.direction = DMA_MEM_TO_DEV;
		cfg.src_addr = 0;
		cfg.dst_addr = host->reg_phys + REG_DATA_WINDOW;
		dmaengine_slave_config(host->dma_chan_tx, &cfg);

		cfg.direction = DMA_DEV_TO_MEM;
		cfg.src_addr = host->reg_phys + REG_DATA_WINDOW;
		cfg.dst_addr = 0;
		dmaengine_slave_config(host->dma_chan_rx, &cfg);
	}

	switch ((readl(host->base + REG_BUS_WIDTH) >> 3) & 3) {
	case 1:
		mmc->caps |= MMC_CAP_4_BIT_DATA;
		break;
	case 2:
		mmc->caps |= MMC_CAP_4_BIT_DATA | MMC_CAP_8_BIT_DATA;
		break;
	default:
		break;
	}

	writel(0, host->base + REG_INTERRUPT_MASK);

	writel(CMD_SDC_RESET, host->base + REG_COMMAND);
	for (i = 0; i < MAX_RETRIES; i++) {
		if (!(readl(host->base + REG_COMMAND) & CMD_SDC_RESET))
			break;
		udelay(5);
	}

	ret = devm_request_irq(dev, irq, moxart_irq, 0, "moxart-mmc", host);
	if (ret)
		goto out;

	dev_set_drvdata(dev, mmc);
	mmc_add_host(mmc);

	dev_dbg(dev, "IRQ=%d, FIFO is %d bytes\n", irq, host->fifo_width);

	return 0;

out:
	if (mmc)
		mmc_free_host(mmc);
	return ret;
}

static int moxart_remove(struct platform_device *pdev)
{
	struct mmc_host *mmc = dev_get_drvdata(&pdev->dev);
	struct moxart_host *host = mmc_priv(mmc);

	dev_set_drvdata(&pdev->dev, NULL);

	if (mmc) {
		if (!IS_ERR(host->dma_chan_tx))
			dma_release_channel(host->dma_chan_tx);
		if (!IS_ERR(host->dma_chan_rx))
			dma_release_channel(host->dma_chan_rx);
		mmc_remove_host(mmc);
		mmc_free_host(mmc);

		writel(0, host->base + REG_INTERRUPT_MASK);
		writel(0, host->base + REG_POWER_CONTROL);
		writel(readl(host->base + REG_CLOCK_CONTROL) | CLK_OFF,
		       host->base + REG_CLOCK_CONTROL);
	}
	return 0;
}

static const struct of_device_id moxart_mmc_match[] = {
	{ .compatible = "moxa,moxart-mmc" },
	{ .compatible = "faraday,ftsdc010" },
	{ }
};

static struct platform_driver moxart_mmc_driver = {
	.probe      = moxart_probe,
	.remove     = moxart_remove,
	.driver     = {
		.name		= "mmc-moxart",
		.of_match_table	= moxart_mmc_match,
	},
};
module_platform_driver(moxart_mmc_driver);

MODULE_ALIAS("platform:mmc-moxart");
MODULE_DESCRIPTION("MOXA ART MMC driver");
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Jonas Jensen <jonas.jensen@gmail.com>");