xref: /openbmc/linux/drivers/mmc/host/moxart-mmc.c (revision e2c75e76)
1 /*
2  * MOXA ART MMC host driver.
3  *
4  * Copyright (C) 2014 Jonas Jensen
5  *
6  * Jonas Jensen <jonas.jensen@gmail.com>
7  *
8  * Based on code from
9  * Moxa Technologies Co., Ltd. <www.moxa.com>
10  *
11  * This file is licensed under the terms of the GNU General Public
12  * License version 2.  This program is licensed "as is" without any
13  * warranty of any kind, whether express or implied.
14  */
15 
16 #include <linux/module.h>
17 #include <linux/init.h>
18 #include <linux/platform_device.h>
19 #include <linux/delay.h>
20 #include <linux/errno.h>
21 #include <linux/interrupt.h>
22 #include <linux/blkdev.h>
23 #include <linux/dma-mapping.h>
24 #include <linux/dmaengine.h>
25 #include <linux/mmc/host.h>
26 #include <linux/mmc/sd.h>
27 #include <linux/sched.h>
28 #include <linux/io.h>
29 #include <linux/of_address.h>
30 #include <linux/of_irq.h>
31 #include <linux/clk.h>
32 #include <linux/bitops.h>
33 #include <linux/of_dma.h>
34 #include <linux/spinlock.h>
35 
36 #define REG_COMMAND		0
37 #define REG_ARGUMENT		4
38 #define REG_RESPONSE0		8
39 #define REG_RESPONSE1		12
40 #define REG_RESPONSE2		16
41 #define REG_RESPONSE3		20
42 #define REG_RESPONSE_COMMAND	24
43 #define REG_DATA_CONTROL	28
44 #define REG_DATA_TIMER		32
45 #define REG_DATA_LENGTH		36
46 #define REG_STATUS		40
47 #define REG_CLEAR		44
48 #define REG_INTERRUPT_MASK	48
49 #define REG_POWER_CONTROL	52
50 #define REG_CLOCK_CONTROL	56
51 #define REG_BUS_WIDTH		60
52 #define REG_DATA_WINDOW		64
53 #define REG_FEATURE		68
54 #define REG_REVISION		72
55 
56 /* REG_COMMAND */
57 #define CMD_SDC_RESET		BIT(10)
58 #define CMD_EN			BIT(9)
59 #define CMD_APP_CMD		BIT(8)
60 #define CMD_LONG_RSP		BIT(7)
61 #define CMD_NEED_RSP		BIT(6)
62 #define CMD_IDX_MASK		0x3f
63 
64 /* REG_RESPONSE_COMMAND */
65 #define RSP_CMD_APP		BIT(6)
66 #define RSP_CMD_IDX_MASK	0x3f
67 
68 /* REG_DATA_CONTROL */
69 #define DCR_DATA_FIFO_RESET     BIT(8)
70 #define DCR_DATA_THRES          BIT(7)
71 #define DCR_DATA_EN		BIT(6)
72 #define DCR_DMA_EN		BIT(5)
73 #define DCR_DATA_WRITE		BIT(4)
74 #define DCR_BLK_SIZE		0x0f
75 
76 /* REG_DATA_LENGTH */
77 #define DATA_LEN_MASK		0xffffff
78 
79 /* REG_STATUS */
80 #define WRITE_PROT		BIT(12)
81 #define CARD_DETECT		BIT(11)
82 /* 1-10 below can be sent to either registers, interrupt or clear. */
83 #define CARD_CHANGE		BIT(10)
84 #define FIFO_ORUN		BIT(9)
85 #define FIFO_URUN		BIT(8)
86 #define DATA_END		BIT(7)
87 #define CMD_SENT		BIT(6)
88 #define DATA_CRC_OK		BIT(5)
89 #define RSP_CRC_OK		BIT(4)
90 #define DATA_TIMEOUT		BIT(3)
91 #define RSP_TIMEOUT		BIT(2)
92 #define DATA_CRC_FAIL		BIT(1)
93 #define RSP_CRC_FAIL		BIT(0)
94 
95 #define MASK_RSP		(RSP_TIMEOUT | RSP_CRC_FAIL | \
96 				 RSP_CRC_OK  | CARD_DETECT  | CMD_SENT)
97 
98 #define MASK_DATA		(DATA_CRC_OK   | DATA_END | \
99 				 DATA_CRC_FAIL | DATA_TIMEOUT)
100 
101 #define MASK_INTR_PIO		(FIFO_URUN | FIFO_ORUN | CARD_CHANGE)
102 
103 /* REG_POWER_CONTROL */
104 #define SD_POWER_ON		BIT(4)
105 #define SD_POWER_MASK		0x0f
106 
107 /* REG_CLOCK_CONTROL */
108 #define CLK_HISPD		BIT(9)
109 #define CLK_OFF			BIT(8)
110 #define CLK_SD			BIT(7)
111 #define CLK_DIV_MASK		0x7f
112 
113 /* REG_BUS_WIDTH */
114 #define BUS_WIDTH_8		BIT(2)
115 #define BUS_WIDTH_4		BIT(1)
116 #define BUS_WIDTH_1		BIT(0)
117 
118 #define MMC_VDD_360		23
119 #define MIN_POWER		(MMC_VDD_360 - SD_POWER_MASK)
120 #define MAX_RETRIES		500000
121 
122 struct moxart_host {
123 	spinlock_t			lock;
124 
125 	void __iomem			*base;
126 
127 	phys_addr_t			reg_phys;
128 
129 	struct dma_chan			*dma_chan_tx;
130 	struct dma_chan                 *dma_chan_rx;
131 	struct dma_async_tx_descriptor	*tx_desc;
132 	struct mmc_host			*mmc;
133 	struct mmc_request		*mrq;
134 	struct scatterlist		*cur_sg;
135 	struct completion		dma_complete;
136 	struct completion		pio_complete;
137 
138 	u32				num_sg;
139 	u32				data_remain;
140 	u32				data_len;
141 	u32				fifo_width;
142 	u32				timeout;
143 	u32				rate;
144 
145 	long				sysclk;
146 
147 	bool				have_dma;
148 	bool				is_removed;
149 };
150 
151 static inline void moxart_init_sg(struct moxart_host *host,
152 				  struct mmc_data *data)
153 {
154 	host->cur_sg = data->sg;
155 	host->num_sg = data->sg_len;
156 	host->data_remain = host->cur_sg->length;
157 
158 	if (host->data_remain > host->data_len)
159 		host->data_remain = host->data_len;
160 }
161 
162 static inline int moxart_next_sg(struct moxart_host *host)
163 {
164 	int remain;
165 	struct mmc_data *data = host->mrq->cmd->data;
166 
167 	host->cur_sg++;
168 	host->num_sg--;
169 
170 	if (host->num_sg > 0) {
171 		host->data_remain = host->cur_sg->length;
172 		remain = host->data_len - data->bytes_xfered;
173 		if (remain > 0 && remain < host->data_remain)
174 			host->data_remain = remain;
175 	}
176 
177 	return host->num_sg;
178 }
179 
180 static int moxart_wait_for_status(struct moxart_host *host,
181 				  u32 mask, u32 *status)
182 {
183 	int ret = -ETIMEDOUT;
184 	u32 i;
185 
186 	for (i = 0; i < MAX_RETRIES; i++) {
187 		*status = readl(host->base + REG_STATUS);
188 		if (!(*status & mask)) {
189 			udelay(5);
190 			continue;
191 		}
192 		writel(*status & mask, host->base + REG_CLEAR);
193 		ret = 0;
194 		break;
195 	}
196 
197 	if (ret)
198 		dev_err(mmc_dev(host->mmc), "timed out waiting for status\n");
199 
200 	return ret;
201 }
202 
203 
204 static void moxart_send_command(struct moxart_host *host,
205 	struct mmc_command *cmd)
206 {
207 	u32 status, cmdctrl;
208 
209 	writel(RSP_TIMEOUT  | RSP_CRC_OK |
210 	       RSP_CRC_FAIL | CMD_SENT, host->base + REG_CLEAR);
211 	writel(cmd->arg, host->base + REG_ARGUMENT);
212 
213 	cmdctrl = cmd->opcode & CMD_IDX_MASK;
214 	if (cmdctrl == SD_APP_SET_BUS_WIDTH    || cmdctrl == SD_APP_OP_COND   ||
215 	    cmdctrl == SD_APP_SEND_SCR         || cmdctrl == SD_APP_SD_STATUS ||
216 	    cmdctrl == SD_APP_SEND_NUM_WR_BLKS)
217 		cmdctrl |= CMD_APP_CMD;
218 
219 	if (cmd->flags & MMC_RSP_PRESENT)
220 		cmdctrl |= CMD_NEED_RSP;
221 
222 	if (cmd->flags & MMC_RSP_136)
223 		cmdctrl |= CMD_LONG_RSP;
224 
225 	writel(cmdctrl | CMD_EN, host->base + REG_COMMAND);
226 
227 	if (moxart_wait_for_status(host, MASK_RSP, &status) == -ETIMEDOUT)
228 		cmd->error = -ETIMEDOUT;
229 
230 	if (status & RSP_TIMEOUT) {
231 		cmd->error = -ETIMEDOUT;
232 		return;
233 	}
234 	if (status & RSP_CRC_FAIL) {
235 		cmd->error = -EIO;
236 		return;
237 	}
238 	if (status & RSP_CRC_OK) {
239 		if (cmd->flags & MMC_RSP_136) {
240 			cmd->resp[3] = readl(host->base + REG_RESPONSE0);
241 			cmd->resp[2] = readl(host->base + REG_RESPONSE1);
242 			cmd->resp[1] = readl(host->base + REG_RESPONSE2);
243 			cmd->resp[0] = readl(host->base + REG_RESPONSE3);
244 		} else {
245 			cmd->resp[0] = readl(host->base + REG_RESPONSE0);
246 		}
247 	}
248 }
249 
250 static void moxart_dma_complete(void *param)
251 {
252 	struct moxart_host *host = param;
253 
254 	complete(&host->dma_complete);
255 }
256 
257 static void moxart_transfer_dma(struct mmc_data *data, struct moxart_host *host)
258 {
259 	u32 len, dir_slave;
260 	long dma_time;
261 	struct dma_async_tx_descriptor *desc = NULL;
262 	struct dma_chan *dma_chan;
263 
264 	if (host->data_len == data->bytes_xfered)
265 		return;
266 
267 	if (data->flags & MMC_DATA_WRITE) {
268 		dma_chan = host->dma_chan_tx;
269 		dir_slave = DMA_MEM_TO_DEV;
270 	} else {
271 		dma_chan = host->dma_chan_rx;
272 		dir_slave = DMA_DEV_TO_MEM;
273 	}
274 
275 	len = dma_map_sg(dma_chan->device->dev, data->sg,
276 			 data->sg_len, mmc_get_dma_dir(data));
277 
278 	if (len > 0) {
279 		desc = dmaengine_prep_slave_sg(dma_chan, data->sg,
280 					       len, dir_slave,
281 					       DMA_PREP_INTERRUPT |
282 					       DMA_CTRL_ACK);
283 	} else {
284 		dev_err(mmc_dev(host->mmc), "dma_map_sg returned zero length\n");
285 	}
286 
287 	if (desc) {
288 		host->tx_desc = desc;
289 		desc->callback = moxart_dma_complete;
290 		desc->callback_param = host;
291 		dmaengine_submit(desc);
292 		dma_async_issue_pending(dma_chan);
293 	}
294 
295 	data->bytes_xfered += host->data_remain;
296 
297 	dma_time = wait_for_completion_interruptible_timeout(
298 		   &host->dma_complete, host->timeout);
299 
300 	dma_unmap_sg(dma_chan->device->dev,
301 		     data->sg, data->sg_len,
302 		     mmc_get_dma_dir(data));
303 }
304 
305 
306 static void moxart_transfer_pio(struct moxart_host *host)
307 {
308 	struct mmc_data *data = host->mrq->cmd->data;
309 	u32 *sgp, len = 0, remain, status;
310 
311 	if (host->data_len == data->bytes_xfered)
312 		return;
313 
314 	sgp = sg_virt(host->cur_sg);
315 	remain = host->data_remain;
316 
317 	if (data->flags & MMC_DATA_WRITE) {
318 		while (remain > 0) {
319 			if (moxart_wait_for_status(host, FIFO_URUN, &status)
320 			     == -ETIMEDOUT) {
321 				data->error = -ETIMEDOUT;
322 				complete(&host->pio_complete);
323 				return;
324 			}
325 			for (len = 0; len < remain && len < host->fifo_width;) {
326 				iowrite32(*sgp, host->base + REG_DATA_WINDOW);
327 				sgp++;
328 				len += 4;
329 			}
330 			remain -= len;
331 		}
332 
333 	} else {
334 		while (remain > 0) {
335 			if (moxart_wait_for_status(host, FIFO_ORUN, &status)
336 			    == -ETIMEDOUT) {
337 				data->error = -ETIMEDOUT;
338 				complete(&host->pio_complete);
339 				return;
340 			}
341 			for (len = 0; len < remain && len < host->fifo_width;) {
342 				/* SCR data must be read in big endian. */
343 				if (data->mrq->cmd->opcode == SD_APP_SEND_SCR)
344 					*sgp = ioread32be(host->base +
345 							  REG_DATA_WINDOW);
346 				else
347 					*sgp = ioread32(host->base +
348 							REG_DATA_WINDOW);
349 				sgp++;
350 				len += 4;
351 			}
352 			remain -= len;
353 		}
354 	}
355 
356 	data->bytes_xfered += host->data_remain - remain;
357 	host->data_remain = remain;
358 
359 	if (host->data_len != data->bytes_xfered)
360 		moxart_next_sg(host);
361 	else
362 		complete(&host->pio_complete);
363 }
364 
365 static void moxart_prepare_data(struct moxart_host *host)
366 {
367 	struct mmc_data *data = host->mrq->cmd->data;
368 	u32 datactrl;
369 	int blksz_bits;
370 
371 	if (!data)
372 		return;
373 
374 	host->data_len = data->blocks * data->blksz;
375 	blksz_bits = ffs(data->blksz) - 1;
376 	BUG_ON(1 << blksz_bits != data->blksz);
377 
378 	moxart_init_sg(host, data);
379 
380 	datactrl = DCR_DATA_EN | (blksz_bits & DCR_BLK_SIZE);
381 
382 	if (data->flags & MMC_DATA_WRITE)
383 		datactrl |= DCR_DATA_WRITE;
384 
385 	if ((host->data_len > host->fifo_width) && host->have_dma)
386 		datactrl |= DCR_DMA_EN;
387 
388 	writel(DCR_DATA_FIFO_RESET, host->base + REG_DATA_CONTROL);
389 	writel(MASK_DATA | FIFO_URUN | FIFO_ORUN, host->base + REG_CLEAR);
390 	writel(host->rate, host->base + REG_DATA_TIMER);
391 	writel(host->data_len, host->base + REG_DATA_LENGTH);
392 	writel(datactrl, host->base + REG_DATA_CONTROL);
393 }
394 
395 static void moxart_request(struct mmc_host *mmc, struct mmc_request *mrq)
396 {
397 	struct moxart_host *host = mmc_priv(mmc);
398 	long pio_time;
399 	unsigned long flags;
400 	u32 status;
401 
402 	spin_lock_irqsave(&host->lock, flags);
403 
404 	init_completion(&host->dma_complete);
405 	init_completion(&host->pio_complete);
406 
407 	host->mrq = mrq;
408 
409 	if (readl(host->base + REG_STATUS) & CARD_DETECT) {
410 		mrq->cmd->error = -ETIMEDOUT;
411 		goto request_done;
412 	}
413 
414 	moxart_prepare_data(host);
415 	moxart_send_command(host, host->mrq->cmd);
416 
417 	if (mrq->cmd->data) {
418 		if ((host->data_len > host->fifo_width) && host->have_dma) {
419 
420 			writel(CARD_CHANGE, host->base + REG_INTERRUPT_MASK);
421 
422 			spin_unlock_irqrestore(&host->lock, flags);
423 
424 			moxart_transfer_dma(mrq->cmd->data, host);
425 
426 			spin_lock_irqsave(&host->lock, flags);
427 		} else {
428 
429 			writel(MASK_INTR_PIO, host->base + REG_INTERRUPT_MASK);
430 
431 			spin_unlock_irqrestore(&host->lock, flags);
432 
433 			/* PIO transfers start from interrupt. */
434 			pio_time = wait_for_completion_interruptible_timeout(
435 				   &host->pio_complete, host->timeout);
436 
437 			spin_lock_irqsave(&host->lock, flags);
438 		}
439 
440 		if (host->is_removed) {
441 			dev_err(mmc_dev(host->mmc), "card removed\n");
442 			mrq->cmd->error = -ETIMEDOUT;
443 			goto request_done;
444 		}
445 
446 		if (moxart_wait_for_status(host, MASK_DATA, &status)
447 		    == -ETIMEDOUT) {
448 			mrq->cmd->data->error = -ETIMEDOUT;
449 			goto request_done;
450 		}
451 
452 		if (status & DATA_CRC_FAIL)
453 			mrq->cmd->data->error = -ETIMEDOUT;
454 
455 		if (mrq->cmd->data->stop)
456 			moxart_send_command(host, mrq->cmd->data->stop);
457 	}
458 
459 request_done:
460 	spin_unlock_irqrestore(&host->lock, flags);
461 	mmc_request_done(host->mmc, mrq);
462 }
463 
464 static irqreturn_t moxart_irq(int irq, void *devid)
465 {
466 	struct moxart_host *host = (struct moxart_host *)devid;
467 	u32 status;
468 	unsigned long flags;
469 
470 	spin_lock_irqsave(&host->lock, flags);
471 
472 	status = readl(host->base + REG_STATUS);
473 	if (status & CARD_CHANGE) {
474 		host->is_removed = status & CARD_DETECT;
475 		if (host->is_removed && host->have_dma) {
476 			dmaengine_terminate_all(host->dma_chan_tx);
477 			dmaengine_terminate_all(host->dma_chan_rx);
478 		}
479 		host->mrq = NULL;
480 		writel(MASK_INTR_PIO, host->base + REG_CLEAR);
481 		writel(CARD_CHANGE, host->base + REG_INTERRUPT_MASK);
482 		mmc_detect_change(host->mmc, 0);
483 	}
484 	if (status & (FIFO_ORUN | FIFO_URUN) && host->mrq)
485 		moxart_transfer_pio(host);
486 
487 	spin_unlock_irqrestore(&host->lock, flags);
488 
489 	return IRQ_HANDLED;
490 }
491 
492 static void moxart_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
493 {
494 	struct moxart_host *host = mmc_priv(mmc);
495 	unsigned long flags;
496 	u8 power, div;
497 	u32 ctrl;
498 
499 	spin_lock_irqsave(&host->lock, flags);
500 
501 	if (ios->clock) {
502 		for (div = 0; div < CLK_DIV_MASK; ++div) {
503 			if (ios->clock >= host->sysclk / (2 * (div + 1)))
504 				break;
505 		}
506 		ctrl = CLK_SD | div;
507 		host->rate = host->sysclk / (2 * (div + 1));
508 		if (host->rate > host->sysclk)
509 			ctrl |= CLK_HISPD;
510 		writel(ctrl, host->base + REG_CLOCK_CONTROL);
511 	}
512 
513 	if (ios->power_mode == MMC_POWER_OFF) {
514 		writel(readl(host->base + REG_POWER_CONTROL) & ~SD_POWER_ON,
515 		       host->base + REG_POWER_CONTROL);
516 	} else {
517 		if (ios->vdd < MIN_POWER)
518 			power = 0;
519 		else
520 			power = ios->vdd - MIN_POWER;
521 
522 		writel(SD_POWER_ON | (u32) power,
523 		       host->base + REG_POWER_CONTROL);
524 	}
525 
526 	switch (ios->bus_width) {
527 	case MMC_BUS_WIDTH_4:
528 		writel(BUS_WIDTH_4, host->base + REG_BUS_WIDTH);
529 		break;
530 	case MMC_BUS_WIDTH_8:
531 		writel(BUS_WIDTH_8, host->base + REG_BUS_WIDTH);
532 		break;
533 	default:
534 		writel(BUS_WIDTH_1, host->base + REG_BUS_WIDTH);
535 		break;
536 	}
537 
538 	spin_unlock_irqrestore(&host->lock, flags);
539 }
540 
541 
542 static int moxart_get_ro(struct mmc_host *mmc)
543 {
544 	struct moxart_host *host = mmc_priv(mmc);
545 
546 	return !!(readl(host->base + REG_STATUS) & WRITE_PROT);
547 }
548 
549 static const struct mmc_host_ops moxart_ops = {
550 	.request = moxart_request,
551 	.set_ios = moxart_set_ios,
552 	.get_ro = moxart_get_ro,
553 };
554 
555 static int moxart_probe(struct platform_device *pdev)
556 {
557 	struct device *dev = &pdev->dev;
558 	struct device_node *node = dev->of_node;
559 	struct resource res_mmc;
560 	struct mmc_host *mmc;
561 	struct moxart_host *host = NULL;
562 	struct dma_slave_config cfg;
563 	struct clk *clk;
564 	void __iomem *reg_mmc;
565 	int irq, ret;
566 	u32 i;
567 
568 	mmc = mmc_alloc_host(sizeof(struct moxart_host), dev);
569 	if (!mmc) {
570 		dev_err(dev, "mmc_alloc_host failed\n");
571 		ret = -ENOMEM;
572 		goto out;
573 	}
574 
575 	ret = of_address_to_resource(node, 0, &res_mmc);
576 	if (ret) {
577 		dev_err(dev, "of_address_to_resource failed\n");
578 		goto out;
579 	}
580 
581 	irq = irq_of_parse_and_map(node, 0);
582 	if (irq <= 0) {
583 		dev_err(dev, "irq_of_parse_and_map failed\n");
584 		ret = -EINVAL;
585 		goto out;
586 	}
587 
588 	clk = devm_clk_get(dev, NULL);
589 	if (IS_ERR(clk)) {
590 		ret = PTR_ERR(clk);
591 		goto out;
592 	}
593 
594 	reg_mmc = devm_ioremap_resource(dev, &res_mmc);
595 	if (IS_ERR(reg_mmc)) {
596 		ret = PTR_ERR(reg_mmc);
597 		goto out;
598 	}
599 
600 	ret = mmc_of_parse(mmc);
601 	if (ret)
602 		goto out;
603 
604 	host = mmc_priv(mmc);
605 	host->mmc = mmc;
606 	host->base = reg_mmc;
607 	host->reg_phys = res_mmc.start;
608 	host->timeout = msecs_to_jiffies(1000);
609 	host->sysclk = clk_get_rate(clk);
610 	host->fifo_width = readl(host->base + REG_FEATURE) << 2;
611 	host->dma_chan_tx = dma_request_slave_channel_reason(dev, "tx");
612 	host->dma_chan_rx = dma_request_slave_channel_reason(dev, "rx");
613 
614 	spin_lock_init(&host->lock);
615 
616 	mmc->ops = &moxart_ops;
617 	mmc->f_max = DIV_ROUND_CLOSEST(host->sysclk, 2);
618 	mmc->f_min = DIV_ROUND_CLOSEST(host->sysclk, CLK_DIV_MASK * 2);
619 	mmc->ocr_avail = 0xffff00;	/* Support 2.0v - 3.6v power. */
620 
621 	if (IS_ERR(host->dma_chan_tx) || IS_ERR(host->dma_chan_rx)) {
622 		if (PTR_ERR(host->dma_chan_tx) == -EPROBE_DEFER ||
623 		    PTR_ERR(host->dma_chan_rx) == -EPROBE_DEFER) {
624 			ret = -EPROBE_DEFER;
625 			goto out;
626 		}
627 		dev_dbg(dev, "PIO mode transfer enabled\n");
628 		host->have_dma = false;
629 	} else {
630 		dev_dbg(dev, "DMA channels found (%p,%p)\n",
631 			 host->dma_chan_tx, host->dma_chan_rx);
632 		host->have_dma = true;
633 
634 		cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
635 		cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
636 
637 		cfg.direction = DMA_MEM_TO_DEV;
638 		cfg.src_addr = 0;
639 		cfg.dst_addr = host->reg_phys + REG_DATA_WINDOW;
640 		dmaengine_slave_config(host->dma_chan_tx, &cfg);
641 
642 		cfg.direction = DMA_DEV_TO_MEM;
643 		cfg.src_addr = host->reg_phys + REG_DATA_WINDOW;
644 		cfg.dst_addr = 0;
645 		dmaengine_slave_config(host->dma_chan_rx, &cfg);
646 	}
647 
648 	switch ((readl(host->base + REG_BUS_WIDTH) >> 3) & 3) {
649 	case 1:
650 		mmc->caps |= MMC_CAP_4_BIT_DATA;
651 		break;
652 	case 2:
653 		mmc->caps |= MMC_CAP_4_BIT_DATA | MMC_CAP_8_BIT_DATA;
654 		break;
655 	default:
656 		break;
657 	}
658 
659 	writel(0, host->base + REG_INTERRUPT_MASK);
660 
661 	writel(CMD_SDC_RESET, host->base + REG_COMMAND);
662 	for (i = 0; i < MAX_RETRIES; i++) {
663 		if (!(readl(host->base + REG_COMMAND) & CMD_SDC_RESET))
664 			break;
665 		udelay(5);
666 	}
667 
668 	ret = devm_request_irq(dev, irq, moxart_irq, 0, "moxart-mmc", host);
669 	if (ret)
670 		goto out;
671 
672 	dev_set_drvdata(dev, mmc);
673 	mmc_add_host(mmc);
674 
675 	dev_dbg(dev, "IRQ=%d, FIFO is %d bytes\n", irq, host->fifo_width);
676 
677 	return 0;
678 
679 out:
680 	if (mmc)
681 		mmc_free_host(mmc);
682 	return ret;
683 }
684 
685 static int moxart_remove(struct platform_device *pdev)
686 {
687 	struct mmc_host *mmc = dev_get_drvdata(&pdev->dev);
688 	struct moxart_host *host = mmc_priv(mmc);
689 
690 	dev_set_drvdata(&pdev->dev, NULL);
691 
692 	if (mmc) {
693 		if (!IS_ERR(host->dma_chan_tx))
694 			dma_release_channel(host->dma_chan_tx);
695 		if (!IS_ERR(host->dma_chan_rx))
696 			dma_release_channel(host->dma_chan_rx);
697 		mmc_remove_host(mmc);
698 		mmc_free_host(mmc);
699 
700 		writel(0, host->base + REG_INTERRUPT_MASK);
701 		writel(0, host->base + REG_POWER_CONTROL);
702 		writel(readl(host->base + REG_CLOCK_CONTROL) | CLK_OFF,
703 		       host->base + REG_CLOCK_CONTROL);
704 	}
705 	return 0;
706 }
707 
708 static const struct of_device_id moxart_mmc_match[] = {
709 	{ .compatible = "moxa,moxart-mmc" },
710 	{ .compatible = "faraday,ftsdc010" },
711 	{ }
712 };
713 MODULE_DEVICE_TABLE(of, moxart_mmc_match);
714 
715 static struct platform_driver moxart_mmc_driver = {
716 	.probe      = moxart_probe,
717 	.remove     = moxart_remove,
718 	.driver     = {
719 		.name		= "mmc-moxart",
720 		.of_match_table	= moxart_mmc_match,
721 	},
722 };
723 module_platform_driver(moxart_mmc_driver);
724 
725 MODULE_ALIAS("platform:mmc-moxart");
726 MODULE_DESCRIPTION("MOXA ART MMC driver");
727 MODULE_LICENSE("GPL v2");
728 MODULE_AUTHOR("Jonas Jensen <jonas.jensen@gmail.com>");
729