xref: /openbmc/linux/drivers/mmc/host/moxart-mmc.c (revision d58f75de)
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 	struct dma_async_tx_descriptor *desc = NULL;
261 	struct dma_chan *dma_chan;
262 
263 	if (host->data_len == data->bytes_xfered)
264 		return;
265 
266 	if (data->flags & MMC_DATA_WRITE) {
267 		dma_chan = host->dma_chan_tx;
268 		dir_slave = DMA_MEM_TO_DEV;
269 	} else {
270 		dma_chan = host->dma_chan_rx;
271 		dir_slave = DMA_DEV_TO_MEM;
272 	}
273 
274 	len = dma_map_sg(dma_chan->device->dev, data->sg,
275 			 data->sg_len, mmc_get_dma_dir(data));
276 
277 	if (len > 0) {
278 		desc = dmaengine_prep_slave_sg(dma_chan, data->sg,
279 					       len, dir_slave,
280 					       DMA_PREP_INTERRUPT |
281 					       DMA_CTRL_ACK);
282 	} else {
283 		dev_err(mmc_dev(host->mmc), "dma_map_sg returned zero length\n");
284 	}
285 
286 	if (desc) {
287 		host->tx_desc = desc;
288 		desc->callback = moxart_dma_complete;
289 		desc->callback_param = host;
290 		dmaengine_submit(desc);
291 		dma_async_issue_pending(dma_chan);
292 	}
293 
294 	data->bytes_xfered += host->data_remain;
295 
296 	wait_for_completion_interruptible_timeout(&host->dma_complete,
297 						  host->timeout);
298 
299 	dma_unmap_sg(dma_chan->device->dev,
300 		     data->sg, data->sg_len,
301 		     mmc_get_dma_dir(data));
302 }
303 
304 
305 static void moxart_transfer_pio(struct moxart_host *host)
306 {
307 	struct mmc_data *data = host->mrq->cmd->data;
308 	u32 *sgp, len = 0, remain, status;
309 
310 	if (host->data_len == data->bytes_xfered)
311 		return;
312 
313 	sgp = sg_virt(host->cur_sg);
314 	remain = host->data_remain;
315 
316 	if (data->flags & MMC_DATA_WRITE) {
317 		while (remain > 0) {
318 			if (moxart_wait_for_status(host, FIFO_URUN, &status)
319 			     == -ETIMEDOUT) {
320 				data->error = -ETIMEDOUT;
321 				complete(&host->pio_complete);
322 				return;
323 			}
324 			for (len = 0; len < remain && len < host->fifo_width;) {
325 				iowrite32(*sgp, host->base + REG_DATA_WINDOW);
326 				sgp++;
327 				len += 4;
328 			}
329 			remain -= len;
330 		}
331 
332 	} else {
333 		while (remain > 0) {
334 			if (moxart_wait_for_status(host, FIFO_ORUN, &status)
335 			    == -ETIMEDOUT) {
336 				data->error = -ETIMEDOUT;
337 				complete(&host->pio_complete);
338 				return;
339 			}
340 			for (len = 0; len < remain && len < host->fifo_width;) {
341 				/* SCR data must be read in big endian. */
342 				if (data->mrq->cmd->opcode == SD_APP_SEND_SCR)
343 					*sgp = ioread32be(host->base +
344 							  REG_DATA_WINDOW);
345 				else
346 					*sgp = ioread32(host->base +
347 							REG_DATA_WINDOW);
348 				sgp++;
349 				len += 4;
350 			}
351 			remain -= len;
352 		}
353 	}
354 
355 	data->bytes_xfered += host->data_remain - remain;
356 	host->data_remain = remain;
357 
358 	if (host->data_len != data->bytes_xfered)
359 		moxart_next_sg(host);
360 	else
361 		complete(&host->pio_complete);
362 }
363 
364 static void moxart_prepare_data(struct moxart_host *host)
365 {
366 	struct mmc_data *data = host->mrq->cmd->data;
367 	u32 datactrl;
368 	int blksz_bits;
369 
370 	if (!data)
371 		return;
372 
373 	host->data_len = data->blocks * data->blksz;
374 	blksz_bits = ffs(data->blksz) - 1;
375 	BUG_ON(1 << blksz_bits != data->blksz);
376 
377 	moxart_init_sg(host, data);
378 
379 	datactrl = DCR_DATA_EN | (blksz_bits & DCR_BLK_SIZE);
380 
381 	if (data->flags & MMC_DATA_WRITE)
382 		datactrl |= DCR_DATA_WRITE;
383 
384 	if ((host->data_len > host->fifo_width) && host->have_dma)
385 		datactrl |= DCR_DMA_EN;
386 
387 	writel(DCR_DATA_FIFO_RESET, host->base + REG_DATA_CONTROL);
388 	writel(MASK_DATA | FIFO_URUN | FIFO_ORUN, host->base + REG_CLEAR);
389 	writel(host->rate, host->base + REG_DATA_TIMER);
390 	writel(host->data_len, host->base + REG_DATA_LENGTH);
391 	writel(datactrl, host->base + REG_DATA_CONTROL);
392 }
393 
394 static void moxart_request(struct mmc_host *mmc, struct mmc_request *mrq)
395 {
396 	struct moxart_host *host = mmc_priv(mmc);
397 	unsigned long flags;
398 	u32 status;
399 
400 	spin_lock_irqsave(&host->lock, flags);
401 
402 	init_completion(&host->dma_complete);
403 	init_completion(&host->pio_complete);
404 
405 	host->mrq = mrq;
406 
407 	if (readl(host->base + REG_STATUS) & CARD_DETECT) {
408 		mrq->cmd->error = -ETIMEDOUT;
409 		goto request_done;
410 	}
411 
412 	moxart_prepare_data(host);
413 	moxart_send_command(host, host->mrq->cmd);
414 
415 	if (mrq->cmd->data) {
416 		if ((host->data_len > host->fifo_width) && host->have_dma) {
417 
418 			writel(CARD_CHANGE, host->base + REG_INTERRUPT_MASK);
419 
420 			spin_unlock_irqrestore(&host->lock, flags);
421 
422 			moxart_transfer_dma(mrq->cmd->data, host);
423 
424 			spin_lock_irqsave(&host->lock, flags);
425 		} else {
426 
427 			writel(MASK_INTR_PIO, host->base + REG_INTERRUPT_MASK);
428 
429 			spin_unlock_irqrestore(&host->lock, flags);
430 
431 			/* PIO transfers start from interrupt. */
432 			wait_for_completion_interruptible_timeout(&host->pio_complete,
433 								  host->timeout);
434 
435 			spin_lock_irqsave(&host->lock, flags);
436 		}
437 
438 		if (host->is_removed) {
439 			dev_err(mmc_dev(host->mmc), "card removed\n");
440 			mrq->cmd->error = -ETIMEDOUT;
441 			goto request_done;
442 		}
443 
444 		if (moxart_wait_for_status(host, MASK_DATA, &status)
445 		    == -ETIMEDOUT) {
446 			mrq->cmd->data->error = -ETIMEDOUT;
447 			goto request_done;
448 		}
449 
450 		if (status & DATA_CRC_FAIL)
451 			mrq->cmd->data->error = -ETIMEDOUT;
452 
453 		if (mrq->cmd->data->stop)
454 			moxart_send_command(host, mrq->cmd->data->stop);
455 	}
456 
457 request_done:
458 	spin_unlock_irqrestore(&host->lock, flags);
459 	mmc_request_done(host->mmc, mrq);
460 }
461 
462 static irqreturn_t moxart_irq(int irq, void *devid)
463 {
464 	struct moxart_host *host = (struct moxart_host *)devid;
465 	u32 status;
466 
467 	spin_lock(&host->lock);
468 
469 	status = readl(host->base + REG_STATUS);
470 	if (status & CARD_CHANGE) {
471 		host->is_removed = status & CARD_DETECT;
472 		if (host->is_removed && host->have_dma) {
473 			dmaengine_terminate_all(host->dma_chan_tx);
474 			dmaengine_terminate_all(host->dma_chan_rx);
475 		}
476 		host->mrq = NULL;
477 		writel(MASK_INTR_PIO, host->base + REG_CLEAR);
478 		writel(CARD_CHANGE, host->base + REG_INTERRUPT_MASK);
479 		mmc_detect_change(host->mmc, 0);
480 	}
481 	if (status & (FIFO_ORUN | FIFO_URUN) && host->mrq)
482 		moxart_transfer_pio(host);
483 
484 	spin_unlock(&host->lock);
485 
486 	return IRQ_HANDLED;
487 }
488 
489 static void moxart_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
490 {
491 	struct moxart_host *host = mmc_priv(mmc);
492 	unsigned long flags;
493 	u8 power, div;
494 	u32 ctrl;
495 
496 	spin_lock_irqsave(&host->lock, flags);
497 
498 	if (ios->clock) {
499 		for (div = 0; div < CLK_DIV_MASK; ++div) {
500 			if (ios->clock >= host->sysclk / (2 * (div + 1)))
501 				break;
502 		}
503 		ctrl = CLK_SD | div;
504 		host->rate = host->sysclk / (2 * (div + 1));
505 		if (host->rate > host->sysclk)
506 			ctrl |= CLK_HISPD;
507 		writel(ctrl, host->base + REG_CLOCK_CONTROL);
508 	}
509 
510 	if (ios->power_mode == MMC_POWER_OFF) {
511 		writel(readl(host->base + REG_POWER_CONTROL) & ~SD_POWER_ON,
512 		       host->base + REG_POWER_CONTROL);
513 	} else {
514 		if (ios->vdd < MIN_POWER)
515 			power = 0;
516 		else
517 			power = ios->vdd - MIN_POWER;
518 
519 		writel(SD_POWER_ON | (u32) power,
520 		       host->base + REG_POWER_CONTROL);
521 	}
522 
523 	switch (ios->bus_width) {
524 	case MMC_BUS_WIDTH_4:
525 		writel(BUS_WIDTH_4, host->base + REG_BUS_WIDTH);
526 		break;
527 	case MMC_BUS_WIDTH_8:
528 		writel(BUS_WIDTH_8, host->base + REG_BUS_WIDTH);
529 		break;
530 	default:
531 		writel(BUS_WIDTH_1, host->base + REG_BUS_WIDTH);
532 		break;
533 	}
534 
535 	spin_unlock_irqrestore(&host->lock, flags);
536 }
537 
538 
539 static int moxart_get_ro(struct mmc_host *mmc)
540 {
541 	struct moxart_host *host = mmc_priv(mmc);
542 
543 	return !!(readl(host->base + REG_STATUS) & WRITE_PROT);
544 }
545 
546 static const struct mmc_host_ops moxart_ops = {
547 	.request = moxart_request,
548 	.set_ios = moxart_set_ios,
549 	.get_ro = moxart_get_ro,
550 };
551 
552 static int moxart_probe(struct platform_device *pdev)
553 {
554 	struct device *dev = &pdev->dev;
555 	struct device_node *node = dev->of_node;
556 	struct resource res_mmc;
557 	struct mmc_host *mmc;
558 	struct moxart_host *host = NULL;
559 	struct dma_slave_config cfg;
560 	struct clk *clk;
561 	void __iomem *reg_mmc;
562 	int irq, ret;
563 	u32 i;
564 
565 	mmc = mmc_alloc_host(sizeof(struct moxart_host), dev);
566 	if (!mmc) {
567 		dev_err(dev, "mmc_alloc_host failed\n");
568 		ret = -ENOMEM;
569 		goto out;
570 	}
571 
572 	ret = of_address_to_resource(node, 0, &res_mmc);
573 	if (ret) {
574 		dev_err(dev, "of_address_to_resource failed\n");
575 		goto out;
576 	}
577 
578 	irq = irq_of_parse_and_map(node, 0);
579 	if (irq <= 0) {
580 		dev_err(dev, "irq_of_parse_and_map failed\n");
581 		ret = -EINVAL;
582 		goto out;
583 	}
584 
585 	clk = devm_clk_get(dev, NULL);
586 	if (IS_ERR(clk)) {
587 		ret = PTR_ERR(clk);
588 		goto out;
589 	}
590 
591 	reg_mmc = devm_ioremap_resource(dev, &res_mmc);
592 	if (IS_ERR(reg_mmc)) {
593 		ret = PTR_ERR(reg_mmc);
594 		goto out;
595 	}
596 
597 	ret = mmc_of_parse(mmc);
598 	if (ret)
599 		goto out;
600 
601 	host = mmc_priv(mmc);
602 	host->mmc = mmc;
603 	host->base = reg_mmc;
604 	host->reg_phys = res_mmc.start;
605 	host->timeout = msecs_to_jiffies(1000);
606 	host->sysclk = clk_get_rate(clk);
607 	host->fifo_width = readl(host->base + REG_FEATURE) << 2;
608 	host->dma_chan_tx = dma_request_chan(dev, "tx");
609 	host->dma_chan_rx = dma_request_chan(dev, "rx");
610 
611 	spin_lock_init(&host->lock);
612 
613 	mmc->ops = &moxart_ops;
614 	mmc->f_max = DIV_ROUND_CLOSEST(host->sysclk, 2);
615 	mmc->f_min = DIV_ROUND_CLOSEST(host->sysclk, CLK_DIV_MASK * 2);
616 	mmc->ocr_avail = 0xffff00;	/* Support 2.0v - 3.6v power. */
617 
618 	if (IS_ERR(host->dma_chan_tx) || IS_ERR(host->dma_chan_rx)) {
619 		if (PTR_ERR(host->dma_chan_tx) == -EPROBE_DEFER ||
620 		    PTR_ERR(host->dma_chan_rx) == -EPROBE_DEFER) {
621 			ret = -EPROBE_DEFER;
622 			goto out;
623 		}
624 		dev_dbg(dev, "PIO mode transfer enabled\n");
625 		host->have_dma = false;
626 	} else {
627 		dev_dbg(dev, "DMA channels found (%p,%p)\n",
628 			 host->dma_chan_tx, host->dma_chan_rx);
629 		host->have_dma = true;
630 
631 		cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
632 		cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
633 
634 		cfg.direction = DMA_MEM_TO_DEV;
635 		cfg.src_addr = 0;
636 		cfg.dst_addr = host->reg_phys + REG_DATA_WINDOW;
637 		dmaengine_slave_config(host->dma_chan_tx, &cfg);
638 
639 		cfg.direction = DMA_DEV_TO_MEM;
640 		cfg.src_addr = host->reg_phys + REG_DATA_WINDOW;
641 		cfg.dst_addr = 0;
642 		dmaengine_slave_config(host->dma_chan_rx, &cfg);
643 	}
644 
645 	switch ((readl(host->base + REG_BUS_WIDTH) >> 3) & 3) {
646 	case 1:
647 		mmc->caps |= MMC_CAP_4_BIT_DATA;
648 		break;
649 	case 2:
650 		mmc->caps |= MMC_CAP_4_BIT_DATA | MMC_CAP_8_BIT_DATA;
651 		break;
652 	default:
653 		break;
654 	}
655 
656 	writel(0, host->base + REG_INTERRUPT_MASK);
657 
658 	writel(CMD_SDC_RESET, host->base + REG_COMMAND);
659 	for (i = 0; i < MAX_RETRIES; i++) {
660 		if (!(readl(host->base + REG_COMMAND) & CMD_SDC_RESET))
661 			break;
662 		udelay(5);
663 	}
664 
665 	ret = devm_request_irq(dev, irq, moxart_irq, 0, "moxart-mmc", host);
666 	if (ret)
667 		goto out;
668 
669 	dev_set_drvdata(dev, mmc);
670 	mmc_add_host(mmc);
671 
672 	dev_dbg(dev, "IRQ=%d, FIFO is %d bytes\n", irq, host->fifo_width);
673 
674 	return 0;
675 
676 out:
677 	if (mmc)
678 		mmc_free_host(mmc);
679 	return ret;
680 }
681 
682 static int moxart_remove(struct platform_device *pdev)
683 {
684 	struct mmc_host *mmc = dev_get_drvdata(&pdev->dev);
685 	struct moxart_host *host = mmc_priv(mmc);
686 
687 	dev_set_drvdata(&pdev->dev, NULL);
688 
689 	if (!IS_ERR(host->dma_chan_tx))
690 		dma_release_channel(host->dma_chan_tx);
691 	if (!IS_ERR(host->dma_chan_rx))
692 		dma_release_channel(host->dma_chan_rx);
693 	mmc_remove_host(mmc);
694 	mmc_free_host(mmc);
695 
696 	writel(0, host->base + REG_INTERRUPT_MASK);
697 	writel(0, host->base + REG_POWER_CONTROL);
698 	writel(readl(host->base + REG_CLOCK_CONTROL) | CLK_OFF,
699 	       host->base + REG_CLOCK_CONTROL);
700 
701 	return 0;
702 }
703 
704 static const struct of_device_id moxart_mmc_match[] = {
705 	{ .compatible = "moxa,moxart-mmc" },
706 	{ .compatible = "faraday,ftsdc010" },
707 	{ }
708 };
709 MODULE_DEVICE_TABLE(of, moxart_mmc_match);
710 
711 static struct platform_driver moxart_mmc_driver = {
712 	.probe      = moxart_probe,
713 	.remove     = moxart_remove,
714 	.driver     = {
715 		.name		= "mmc-moxart",
716 		.probe_type	= PROBE_PREFER_ASYNCHRONOUS,
717 		.of_match_table	= moxart_mmc_match,
718 	},
719 };
720 module_platform_driver(moxart_mmc_driver);
721 
722 MODULE_ALIAS("platform:mmc-moxart");
723 MODULE_DESCRIPTION("MOXA ART MMC driver");
724 MODULE_LICENSE("GPL v2");
725 MODULE_AUTHOR("Jonas Jensen <jonas.jensen@gmail.com>");
726