summaryrefslogtreecommitdiffstats
path: root/drivers/mmc/host/owl-mmc.c
blob: 3dc143b0393972bcd4fff3bb77b5e106dc6cd989 (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
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Actions Semi Owl SoCs SD/MMC driver
 *
 * Copyright (c) 2014 Actions Semi Inc.
 * Copyright (c) 2019 Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
 *
 * TODO: SDIO support
 */

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/dmaengine.h>
#include <linux/dma-direction.h>
#include <linux/dma-mapping.h>
#include <linux/interrupt.h>
#include <linux/mmc/host.h>
#include <linux/mmc/slot-gpio.h>
#include <linux/module.h>
#include <linux/of_platform.h>
#include <linux/reset.h>
#include <linux/spinlock.h>

/*
 * SDC registers
 */
#define OWL_REG_SD_EN			0x0000
#define OWL_REG_SD_CTL			0x0004
#define OWL_REG_SD_STATE		0x0008
#define OWL_REG_SD_CMD			0x000c
#define OWL_REG_SD_ARG			0x0010
#define OWL_REG_SD_RSPBUF0		0x0014
#define OWL_REG_SD_RSPBUF1		0x0018
#define OWL_REG_SD_RSPBUF2		0x001c
#define OWL_REG_SD_RSPBUF3		0x0020
#define OWL_REG_SD_RSPBUF4		0x0024
#define OWL_REG_SD_DAT			0x0028
#define OWL_REG_SD_BLK_SIZE		0x002c
#define OWL_REG_SD_BLK_NUM		0x0030
#define OWL_REG_SD_BUF_SIZE		0x0034

/* SD_EN Bits */
#define OWL_SD_EN_RANE			BIT(31)
#define OWL_SD_EN_RAN_SEED(x)		(((x) & 0x3f) << 24)
#define OWL_SD_EN_S18EN			BIT(12)
#define OWL_SD_EN_RESE			BIT(10)
#define OWL_SD_EN_DAT1_S		BIT(9)
#define OWL_SD_EN_CLK_S			BIT(8)
#define OWL_SD_ENABLE			BIT(7)
#define OWL_SD_EN_BSEL			BIT(6)
#define OWL_SD_EN_SDIOEN		BIT(3)
#define OWL_SD_EN_DDREN			BIT(2)
#define OWL_SD_EN_DATAWID(x)		(((x) & 0x3) << 0)

/* SD_CTL Bits */
#define OWL_SD_CTL_TOUTEN		BIT(31)
#define OWL_SD_CTL_TOUTCNT(x)		(((x) & 0x7f) << 24)
#define OWL_SD_CTL_DELAY_MSK		GENMASK(23, 16)
#define OWL_SD_CTL_RDELAY(x)		(((x) & 0xf) << 20)
#define OWL_SD_CTL_WDELAY(x)		(((x) & 0xf) << 16)
#define OWL_SD_CTL_CMDLEN		BIT(13)
#define OWL_SD_CTL_SCC			BIT(12)
#define OWL_SD_CTL_TCN(x)		(((x) & 0xf) << 8)
#define OWL_SD_CTL_TS			BIT(7)
#define OWL_SD_CTL_LBE			BIT(6)
#define OWL_SD_CTL_C7EN			BIT(5)
#define OWL_SD_CTL_TM(x)		(((x) & 0xf) << 0)

#define OWL_SD_DELAY_LOW_CLK		0x0f
#define OWL_SD_DELAY_MID_CLK		0x0a
#define OWL_SD_DELAY_HIGH_CLK		0x09
#define OWL_SD_RDELAY_DDR50		0x0a
#define OWL_SD_WDELAY_DDR50		0x08

/* SD_STATE Bits */
#define OWL_SD_STATE_DAT1BS		BIT(18)
#define OWL_SD_STATE_SDIOB_P		BIT(17)
#define OWL_SD_STATE_SDIOB_EN		BIT(16)
#define OWL_SD_STATE_TOUTE		BIT(15)
#define OWL_SD_STATE_BAEP		BIT(14)
#define OWL_SD_STATE_MEMRDY		BIT(12)
#define OWL_SD_STATE_CMDS		BIT(11)
#define OWL_SD_STATE_DAT1AS		BIT(10)
#define OWL_SD_STATE_SDIOA_P		BIT(9)
#define OWL_SD_STATE_SDIOA_EN		BIT(8)
#define OWL_SD_STATE_DAT0S		BIT(7)
#define OWL_SD_STATE_TEIE		BIT(6)
#define OWL_SD_STATE_TEI		BIT(5)
#define OWL_SD_STATE_CLNR		BIT(4)
#define OWL_SD_STATE_CLC		BIT(3)
#define OWL_SD_STATE_WC16ER		BIT(2)
#define OWL_SD_STATE_RC16ER		BIT(1)
#define OWL_SD_STATE_CRC7ER		BIT(0)

#define OWL_CMD_TIMEOUT_MS		30000

struct owl_mmc_host {
	struct device *dev;
	struct reset_control *reset;
	void __iomem *base;
	struct clk *clk;
	struct completion sdc_complete;
	spinlock_t lock;
	int irq;
	u32 clock;
	bool ddr_50;

	enum dma_data_direction dma_dir;
	struct dma_chan *dma;
	struct dma_async_tx_descriptor *desc;
	struct dma_slave_config dma_cfg;
	struct completion dma_complete;

	struct mmc_host	*mmc;
	struct mmc_request *mrq;
	struct mmc_command *cmd;
	struct mmc_data	*data;
};

static void owl_mmc_update_reg(void __iomem *reg, unsigned int val, bool state)
{
	unsigned int regval;

	regval = readl(reg);

	if (state)
		regval |= val;
	else
		regval &= ~val;

	writel(regval, reg);
}

static irqreturn_t owl_irq_handler(int irq, void *devid)
{
	struct owl_mmc_host *owl_host = devid;
	u32 state;

	spin_lock(&owl_host->lock);

	state = readl(owl_host->base + OWL_REG_SD_STATE);
	if (state & OWL_SD_STATE_TEI) {
		state = readl(owl_host->base + OWL_REG_SD_STATE);
		state |= OWL_SD_STATE_TEI;
		writel(state, owl_host->base + OWL_REG_SD_STATE);
		complete(&owl_host->sdc_complete);
	}

	spin_unlock(&owl_host->lock);

	return IRQ_HANDLED;
}

static void owl_mmc_finish_request(struct owl_mmc_host *owl_host)
{
	struct mmc_request *mrq = owl_host->mrq;
	struct mmc_data *data = mrq->data;

	/* Should never be NULL */
	WARN_ON(!mrq);

	owl_host->mrq = NULL;

	if (data)
		dma_unmap_sg(owl_host->dma->device->dev, data->sg, data->sg_len,
			     owl_host->dma_dir);

	/* Finally finish request */
	mmc_request_done(owl_host->mmc, mrq);
}

static void owl_mmc_send_cmd(struct owl_mmc_host *owl_host,
			     struct mmc_command *cmd,
			     struct mmc_data *data)
{
	unsigned long timeout;
	u32 mode, state, resp[2];
	u32 cmd_rsp_mask = 0;

	init_completion(&owl_host->sdc_complete);

	switch (mmc_resp_type(cmd)) {
	case MMC_RSP_NONE:
		mode = OWL_SD_CTL_TM(0);
		break;

	case MMC_RSP_R1:
		if (data) {
			if (data->flags & MMC_DATA_READ)
				mode = OWL_SD_CTL_TM(4);
			else
				mode = OWL_SD_CTL_TM(5);
		} else {
			mode = OWL_SD_CTL_TM(1);
		}
		cmd_rsp_mask = OWL_SD_STATE_CLNR | OWL_SD_STATE_CRC7ER;

		break;

	case MMC_RSP_R1B:
		mode = OWL_SD_CTL_TM(3);
		cmd_rsp_mask = OWL_SD_STATE_CLNR | OWL_SD_STATE_CRC7ER;
		break;

	case MMC_RSP_R2:
		mode = OWL_SD_CTL_TM(2);
		cmd_rsp_mask = OWL_SD_STATE_CLNR | OWL_SD_STATE_CRC7ER;
		break;

	case MMC_RSP_R3:
		mode = OWL_SD_CTL_TM(1);
		cmd_rsp_mask = OWL_SD_STATE_CLNR;
		break;

	default:
		dev_warn(owl_host->dev, "Unknown MMC command\n");
		cmd->error = -EINVAL;
		return;
	}

	/* Keep current WDELAY and RDELAY */
	mode |= (readl(owl_host->base + OWL_REG_SD_CTL) & (0xff << 16));

	/* Start to send corresponding command type */
	writel(cmd->arg, owl_host->base + OWL_REG_SD_ARG);
	writel(cmd->opcode, owl_host->base + OWL_REG_SD_CMD);

	/* Set LBE to send clk at the end of last read block */
	if (data) {
		mode |= (OWL_SD_CTL_TS | OWL_SD_CTL_LBE | 0x64000000);
	} else {
		mode &= ~(OWL_SD_CTL_TOUTEN | OWL_SD_CTL_LBE);
		mode |= OWL_SD_CTL_TS;
	}

	owl_host->cmd = cmd;

	/* Start transfer */
	writel(mode, owl_host->base + OWL_REG_SD_CTL);

	if (data)
		return;

	timeout = msecs_to_jiffies(cmd->busy_timeout ? cmd->busy_timeout :
		OWL_CMD_TIMEOUT_MS);

	if (!wait_for_completion_timeout(&owl_host->sdc_complete, timeout)) {
		dev_err(owl_host->dev, "CMD interrupt timeout\n");
		cmd->error = -ETIMEDOUT;
		return;
	}

	state = readl(owl_host->base + OWL_REG_SD_STATE);
	if (mmc_resp_type(cmd) & MMC_RSP_PRESENT) {
		if (cmd_rsp_mask & state) {
			if (state & OWL_SD_STATE_CLNR) {
				dev_err(owl_host->dev, "Error CMD_NO_RSP\n");
				cmd->error = -EILSEQ;
				return;
			}

			if (state & OWL_SD_STATE_CRC7ER) {
				dev_err(owl_host->dev, "Error CMD_RSP_CRC\n");
				cmd->error = -EILSEQ;
				return;
			}
		}

		if (mmc_resp_type(cmd) & MMC_RSP_136) {
			cmd->resp[3] = readl(owl_host->base + OWL_REG_SD_RSPBUF0);
			cmd->resp[2] = readl(owl_host->base + OWL_REG_SD_RSPBUF1);
			cmd->resp[1] = readl(owl_host->base + OWL_REG_SD_RSPBUF2);
			cmd->resp[0] = readl(owl_host->base + OWL_REG_SD_RSPBUF3);
		} else {
			resp[0] = readl(owl_host->base + OWL_REG_SD_RSPBUF0);
			resp[1] = readl(owl_host->base + OWL_REG_SD_RSPBUF1);
			cmd->resp[0] = resp[1] << 24 | resp[0] >> 8;
			cmd->resp[1] = resp[1] >> 8;
		}
	}
}

static void owl_mmc_dma_complete(void *param)
{
	struct owl_mmc_host *owl_host = param;
	struct mmc_data *data = owl_host->data;

	if (data)
		complete(&owl_host->dma_complete);
}

static int owl_mmc_prepare_data(struct owl_mmc_host *owl_host,
				struct mmc_data *data)
{
	u32 total;

	owl_mmc_update_reg(owl_host->base + OWL_REG_SD_EN, OWL_SD_EN_BSEL,
			   true);
	writel(data->blocks, owl_host->base + OWL_REG_SD_BLK_NUM);
	writel(data->blksz, owl_host->base + OWL_REG_SD_BLK_SIZE);
	total = data->blksz * data->blocks;

	if (total < 512)
		writel(total, owl_host->base + OWL_REG_SD_BUF_SIZE);
	else
		writel(512, owl_host->base + OWL_REG_SD_BUF_SIZE);

	if (data->flags & MMC_DATA_WRITE) {
		owl_host->dma_dir = DMA_TO_DEVICE;
		owl_host->dma_cfg.direction = DMA_MEM_TO_DEV;
	} else {
		owl_host->dma_dir = DMA_FROM_DEVICE;
		owl_host->dma_cfg.direction = DMA_DEV_TO_MEM;
	}

	dma_map_sg(owl_host->dma->device->dev, data->sg,
		   data->sg_len, owl_host->dma_dir);

	dmaengine_slave_config(owl_host->dma, &owl_host->dma_cfg);
	owl_host->desc = dmaengine_prep_slave_sg(owl_host->dma, data->sg,
						 data->sg_len,
						 owl_host->dma_cfg.direction,
						 DMA_PREP_INTERRUPT |
						 DMA_CTRL_ACK);
	if (!owl_host->desc) {
		dev_err(owl_host->dev, "Can't prepare slave sg\n");
		return -EBUSY;
	}

	owl_host->data = data;

	owl_host->desc->callback = owl_mmc_dma_complete;
	owl_host->desc->callback_param = (void *)owl_host;
	data->error = 0;

	return 0;
}

static void owl_mmc_request(struct mmc_host *mmc, struct mmc_request *mrq)
{
	struct owl_mmc_host *owl_host = mmc_priv(mmc);
	struct mmc_data *data = mrq->data;
	int ret;

	owl_host->mrq = mrq;
	if (mrq->data) {
		ret = owl_mmc_prepare_data(owl_host, data);
		if (ret < 0) {
			data->error = ret;
			goto err_out;
		}

		init_completion(&owl_host->dma_complete);
		dmaengine_submit(owl_host->desc);
		dma_async_issue_pending(owl_host->dma);
	}

	owl_mmc_send_cmd(owl_host, mrq->cmd, data);

	if (data) {
		if (!wait_for_completion_timeout(&owl_host->sdc_complete,
						 10 * HZ)) {
			dev_err(owl_host->dev, "CMD interrupt timeout\n");
			mrq->cmd->error = -ETIMEDOUT;
			dmaengine_terminate_all(owl_host->dma);
			goto err_out;
		}

		if (!wait_for_completion_timeout(&owl_host->dma_complete,
						 5 * HZ)) {
			dev_err(owl_host->dev, "DMA interrupt timeout\n");
			mrq->cmd->error = -ETIMEDOUT;
			dmaengine_terminate_all(owl_host->dma);
			goto err_out;
		}

		if (data->stop)
			owl_mmc_send_cmd(owl_host, data->stop, NULL);

		data->bytes_xfered = data->blocks * data->blksz;
	}

err_out:
	owl_mmc_finish_request(owl_host);
}

static int owl_mmc_set_clk_rate(struct owl_mmc_host *owl_host,
				unsigned int rate)
{
	unsigned long clk_rate;
	int ret;
	u32 reg;

	reg = readl(owl_host->base + OWL_REG_SD_CTL);
	reg &= ~OWL_SD_CTL_DELAY_MSK;

	/* Set RDELAY and WDELAY based on the clock */
	if (rate <= 1000000) {
		writel(reg | OWL_SD_CTL_RDELAY(OWL_SD_DELAY_LOW_CLK) |
		       OWL_SD_CTL_WDELAY(OWL_SD_DELAY_LOW_CLK),
		       owl_host->base + OWL_REG_SD_CTL);
	} else if ((rate > 1000000) && (rate <= 26000000)) {
		writel(reg | OWL_SD_CTL_RDELAY(OWL_SD_DELAY_MID_CLK) |
		       OWL_SD_CTL_WDELAY(OWL_SD_DELAY_MID_CLK),
		       owl_host->base + OWL_REG_SD_CTL);
	} else if ((rate > 26000000) && (rate <= 52000000) && !owl_host->ddr_50) {
		writel(reg | OWL_SD_CTL_RDELAY(OWL_SD_DELAY_HIGH_CLK) |
		       OWL_SD_CTL_WDELAY(OWL_SD_DELAY_HIGH_CLK),
		       owl_host->base + OWL_REG_SD_CTL);
	/* DDR50 mode has special delay chain */
	} else if ((rate > 26000000) && (rate <= 52000000) && owl_host->ddr_50) {
		writel(reg | OWL_SD_CTL_RDELAY(OWL_SD_RDELAY_DDR50) |
		       OWL_SD_CTL_WDELAY(OWL_SD_WDELAY_DDR50),
		       owl_host->base + OWL_REG_SD_CTL);
	} else {
		dev_err(owl_host->dev, "SD clock rate not supported\n");
		return -EINVAL;
	}

	clk_rate = clk_round_rate(owl_host->clk, rate << 1);
	ret = clk_set_rate(owl_host->clk, clk_rate);

	return ret;
}

static void owl_mmc_set_clk(struct owl_mmc_host *owl_host, struct mmc_ios *ios)
{
	if (!ios->clock)
		return;

	owl_host->clock = ios->clock;
	owl_mmc_set_clk_rate(owl_host, ios->clock);
}

static void owl_mmc_set_bus_width(struct owl_mmc_host *owl_host,
				  struct mmc_ios *ios)
{
	u32 reg;

	reg = readl(owl_host->base + OWL_REG_SD_EN);
	reg &= ~0x03;
	switch (ios->bus_width) {
	case MMC_BUS_WIDTH_1:
		break;
	case MMC_BUS_WIDTH_4:
		reg |= OWL_SD_EN_DATAWID(1);
		break;
	case MMC_BUS_WIDTH_8:
		reg |= OWL_SD_EN_DATAWID(2);
		break;
	}

	writel(reg, owl_host->base + OWL_REG_SD_EN);
}

static void owl_mmc_ctr_reset(struct owl_mmc_host *owl_host)
{
	reset_control_assert(owl_host->reset);
	udelay(20);
	reset_control_deassert(owl_host->reset);
}

static void owl_mmc_power_on(struct owl_mmc_host *owl_host)
{
	u32 mode;

	init_completion(&owl_host->sdc_complete);

	/* Enable transfer end IRQ */
	owl_mmc_update_reg(owl_host->base + OWL_REG_SD_STATE,
		       OWL_SD_STATE_TEIE, true);

	/* Send init clk */
	mode = (readl(owl_host->base + OWL_REG_SD_CTL) & (0xff << 16));
	mode |= OWL_SD_CTL_TS | OWL_SD_CTL_TCN(5) | OWL_SD_CTL_TM(8);
	writel(mode, owl_host->base + OWL_REG_SD_CTL);

	if (!wait_for_completion_timeout(&owl_host->sdc_complete, HZ)) {
		dev_err(owl_host->dev, "CMD interrupt timeout\n");
		return;
	}
}

static void owl_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
{
	struct owl_mmc_host *owl_host = mmc_priv(mmc);

	switch (ios->power_mode) {
	case MMC_POWER_UP:
		dev_dbg(owl_host->dev, "Powering card up\n");

		/* Reset the SDC controller to clear all previous states */
		owl_mmc_ctr_reset(owl_host);
		clk_prepare_enable(owl_host->clk);
		writel(OWL_SD_ENABLE | OWL_SD_EN_RESE,
		       owl_host->base + OWL_REG_SD_EN);

		break;

	case MMC_POWER_ON:
		dev_dbg(owl_host->dev, "Powering card on\n");
		owl_mmc_power_on(owl_host);

		break;

	case MMC_POWER_OFF:
		dev_dbg(owl_host->dev, "Powering card off\n");
		clk_disable_unprepare(owl_host->clk);

		return;

	default:
		dev_dbg(owl_host->dev, "Ignoring unknown card power state\n");
		break;
	}

	if (ios->clock != owl_host->clock)
		owl_mmc_set_clk(owl_host, ios);

	owl_mmc_set_bus_width(owl_host, ios);

	/* Enable DDR mode if requested */
	if (ios->timing == MMC_TIMING_UHS_DDR50) {
		owl_host->ddr_50 = true;
		owl_mmc_update_reg(owl_host->base + OWL_REG_SD_EN,
			       OWL_SD_EN_DDREN, true);
	} else {
		owl_host->ddr_50 = false;
	}
}

static int owl_mmc_start_signal_voltage_switch(struct mmc_host *mmc,
					       struct mmc_ios *ios)
{
	struct owl_mmc_host *owl_host = mmc_priv(mmc);

	/* It is enough to change the pad ctrl bit for voltage switch */
	switch (ios->signal_voltage) {
	case MMC_SIGNAL_VOLTAGE_330:
		owl_mmc_update_reg(owl_host->base + OWL_REG_SD_EN,
			       OWL_SD_EN_S18EN, false);
		break;
	case MMC_SIGNAL_VOLTAGE_180:
		owl_mmc_update_reg(owl_host->base + OWL_REG_SD_EN,
			       OWL_SD_EN_S18EN, true);
		break;
	default:
		return -ENOTSUPP;
	}

	return 0;
}

static const struct mmc_host_ops owl_mmc_ops = {
	.request	= owl_mmc_request,
	.set_ios	= owl_mmc_set_ios,
	.get_ro		= mmc_gpio_get_ro,
	.get_cd		= mmc_gpio_get_cd,
	.start_signal_voltage_switch = owl_mmc_start_signal_voltage_switch,
};

static int owl_mmc_probe(struct platform_device *pdev)
{
	struct owl_mmc_host *owl_host;
	struct mmc_host *mmc;
	struct resource *res;
	int ret;

	mmc = mmc_alloc_host(sizeof(struct owl_mmc_host), &pdev->dev);
	if (!mmc) {
		dev_err(&pdev->dev, "mmc alloc host failed\n");
		return -ENOMEM;
	}
	platform_set_drvdata(pdev, mmc);

	owl_host = mmc_priv(mmc);
	owl_host->dev = &pdev->dev;
	owl_host->mmc = mmc;
	spin_lock_init(&owl_host->lock);

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	owl_host->base = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(owl_host->base)) {
		ret = PTR_ERR(owl_host->base);
		goto err_free_host;
	}

	owl_host->clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(owl_host->clk)) {
		dev_err(&pdev->dev, "No clock defined\n");
		ret = PTR_ERR(owl_host->clk);
		goto err_free_host;
	}

	owl_host->reset = devm_reset_control_get_exclusive(&pdev->dev, NULL);
	if (IS_ERR(owl_host->reset)) {
		dev_err(&pdev->dev, "Could not get reset control\n");
		ret = PTR_ERR(owl_host->reset);
		goto err_free_host;
	}

	mmc->ops		= &owl_mmc_ops;
	mmc->max_blk_count	= 512;
	mmc->max_blk_size	= 512;
	mmc->max_segs		= 256;
	mmc->max_seg_size	= 262144;
	mmc->max_req_size	= 262144;
	/* 100kHz ~ 52MHz */
	mmc->f_min		= 100000;
	mmc->f_max		= 52000000;
	mmc->caps	       |= MMC_CAP_MMC_HIGHSPEED | MMC_CAP_SD_HIGHSPEED |
				  MMC_CAP_4_BIT_DATA;
	mmc->caps2		= (MMC_CAP2_BOOTPART_NOACC | MMC_CAP2_NO_SDIO);
	mmc->ocr_avail		= MMC_VDD_32_33 | MMC_VDD_33_34 |
				  MMC_VDD_165_195;

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

	pdev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
	pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask;
	owl_host->dma = dma_request_chan(&pdev->dev, "mmc");
	if (IS_ERR(owl_host->dma)) {
		dev_err(owl_host->dev, "Failed to get external DMA channel.\n");
		ret = PTR_ERR(owl_host->dma);
		goto err_free_host;
	}

	dev_info(&pdev->dev, "Using %s for DMA transfers\n",
		 dma_chan_name(owl_host->dma));

	owl_host->dma_cfg.src_addr = res->start + OWL_REG_SD_DAT;
	owl_host->dma_cfg.dst_addr = res->start + OWL_REG_SD_DAT;
	owl_host->dma_cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
	owl_host->dma_cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
	owl_host->dma_cfg.device_fc = false;

	owl_host->irq = platform_get_irq(pdev, 0);
	if (owl_host->irq < 0) {
		ret = -EINVAL;
		goto err_release_channel;
	}

	ret = devm_request_irq(&pdev->dev, owl_host->irq, owl_irq_handler,
			       0, dev_name(&pdev->dev), owl_host);
	if (ret) {
		dev_err(&pdev->dev, "Failed to request irq %d\n",
			owl_host->irq);
		goto err_release_channel;
	}

	ret = mmc_add_host(mmc);
	if (ret) {
		dev_err(&pdev->dev, "Failed to add host\n");
		goto err_release_channel;
	}

	dev_dbg(&pdev->dev, "Owl MMC Controller Initialized\n");

	return 0;

err_release_channel:
	dma_release_channel(owl_host->dma);
err_free_host:
	mmc_free_host(mmc);

	return ret;
}

static int owl_mmc_remove(struct platform_device *pdev)
{
	struct mmc_host	*mmc = platform_get_drvdata(pdev);
	struct owl_mmc_host *owl_host = mmc_priv(mmc);

	mmc_remove_host(mmc);
	disable_irq(owl_host->irq);
	dma_release_channel(owl_host->dma);
	mmc_free_host(mmc);

	return 0;
}

static const struct of_device_id owl_mmc_of_match[] = {
	{.compatible = "actions,owl-mmc",},
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, owl_mmc_of_match);

static struct platform_driver owl_mmc_driver = {
	.driver = {
		.name	= "owl_mmc",
		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
		.of_match_table = owl_mmc_of_match,
	},
	.probe		= owl_mmc_probe,
	.remove		= owl_mmc_remove,
};
module_platform_driver(owl_mmc_driver);

MODULE_DESCRIPTION("Actions Semi Owl SoCs SD/MMC Driver");
MODULE_AUTHOR("Actions Semi");
MODULE_AUTHOR("Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>");
MODULE_LICENSE("GPL");