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  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_4_SUPPORT	BIT(3)
115#define BUS_WIDTH_4		BIT(2)
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
122struct 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
151static 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
162static 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
180static 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
204static 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
250static void moxart_dma_complete(void *param)
251{
252	struct moxart_host *host = param;
253
254	complete(&host->dma_complete);
255}
256
257static 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
305static 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
364static 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
394static 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
457request_done:
458	spin_unlock_irqrestore(&host->lock, flags);
459	mmc_request_done(host->mmc, mrq);
460}
461
462static 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
489static 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	default:
528		writel(BUS_WIDTH_1, host->base + REG_BUS_WIDTH);
529		break;
530	}
531
532	spin_unlock_irqrestore(&host->lock, flags);
533}
534
535
536static int moxart_get_ro(struct mmc_host *mmc)
537{
538	struct moxart_host *host = mmc_priv(mmc);
539
540	return !!(readl(host->base + REG_STATUS) & WRITE_PROT);
541}
542
543static const struct mmc_host_ops moxart_ops = {
544	.request = moxart_request,
545	.set_ios = moxart_set_ios,
546	.get_ro = moxart_get_ro,
547};
548
549static int moxart_probe(struct platform_device *pdev)
550{
551	struct device *dev = &pdev->dev;
552	struct device_node *node = dev->of_node;
553	struct resource res_mmc;
554	struct mmc_host *mmc;
555	struct moxart_host *host = NULL;
556	struct dma_slave_config cfg;
557	struct clk *clk;
558	void __iomem *reg_mmc;
559	int irq, ret;
560	u32 i;
561
562	mmc = mmc_alloc_host(sizeof(struct moxart_host), dev);
563	if (!mmc) {
564		dev_err(dev, "mmc_alloc_host failed\n");
565		ret = -ENOMEM;
566		goto out_mmc;
567	}
568
569	ret = of_address_to_resource(node, 0, &res_mmc);
570	if (ret) {
571		dev_err(dev, "of_address_to_resource failed\n");
572		goto out_mmc;
573	}
574
575	irq = irq_of_parse_and_map(node, 0);
576	if (irq <= 0) {
577		dev_err(dev, "irq_of_parse_and_map failed\n");
578		ret = -EINVAL;
579		goto out_mmc;
580	}
581
582	clk = devm_clk_get(dev, NULL);
583	if (IS_ERR(clk)) {
584		ret = PTR_ERR(clk);
585		goto out_mmc;
586	}
587
588	reg_mmc = devm_ioremap_resource(dev, &res_mmc);
589	if (IS_ERR(reg_mmc)) {
590		ret = PTR_ERR(reg_mmc);
591		goto out_mmc;
592	}
593
594	ret = mmc_of_parse(mmc);
595	if (ret)
596		goto out_mmc;
597
598	host = mmc_priv(mmc);
599	host->mmc = mmc;
600	host->base = reg_mmc;
601	host->reg_phys = res_mmc.start;
602	host->timeout = msecs_to_jiffies(1000);
603	host->sysclk = clk_get_rate(clk);
604	host->fifo_width = readl(host->base + REG_FEATURE) << 2;
605	host->dma_chan_tx = dma_request_chan(dev, "tx");
606	host->dma_chan_rx = dma_request_chan(dev, "rx");
607
608	spin_lock_init(&host->lock);
609
610	mmc->ops = &moxart_ops;
611	mmc->f_max = DIV_ROUND_CLOSEST(host->sysclk, 2);
612	mmc->f_min = DIV_ROUND_CLOSEST(host->sysclk, CLK_DIV_MASK * 2);
613	mmc->ocr_avail = 0xffff00;	/* Support 2.0v - 3.6v power. */
614
615	if (IS_ERR(host->dma_chan_tx) || IS_ERR(host->dma_chan_rx)) {
616		if (PTR_ERR(host->dma_chan_tx) == -EPROBE_DEFER ||
617		    PTR_ERR(host->dma_chan_rx) == -EPROBE_DEFER) {
618			ret = -EPROBE_DEFER;
619			goto out;
620		}
621		if (!IS_ERR(host->dma_chan_tx)) {
622			dma_release_channel(host->dma_chan_tx);
623			host->dma_chan_tx = NULL;
624		}
625		if (!IS_ERR(host->dma_chan_rx)) {
626			dma_release_channel(host->dma_chan_rx);
627			host->dma_chan_rx = NULL;
628		}
629		dev_dbg(dev, "PIO mode transfer enabled\n");
630		host->have_dma = false;
631	} else {
632		dev_dbg(dev, "DMA channels found (%p,%p)\n",
633			 host->dma_chan_tx, host->dma_chan_rx);
634		host->have_dma = true;
635
636		memset(&cfg, 0, sizeof(cfg));
637		cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
638		cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
639
640		cfg.direction = DMA_MEM_TO_DEV;
641		cfg.src_addr = 0;
642		cfg.dst_addr = host->reg_phys + REG_DATA_WINDOW;
643		dmaengine_slave_config(host->dma_chan_tx, &cfg);
644
645		cfg.direction = DMA_DEV_TO_MEM;
646		cfg.src_addr = host->reg_phys + REG_DATA_WINDOW;
647		cfg.dst_addr = 0;
648		dmaengine_slave_config(host->dma_chan_rx, &cfg);
649	}
650
651	if (readl(host->base + REG_BUS_WIDTH) & BUS_WIDTH_4_SUPPORT)
652		mmc->caps |= MMC_CAP_4_BIT_DATA;
653
654	writel(0, host->base + REG_INTERRUPT_MASK);
655
656	writel(CMD_SDC_RESET, host->base + REG_COMMAND);
657	for (i = 0; i < MAX_RETRIES; i++) {
658		if (!(readl(host->base + REG_COMMAND) & CMD_SDC_RESET))
659			break;
660		udelay(5);
661	}
662
663	ret = devm_request_irq(dev, irq, moxart_irq, 0, "moxart-mmc", host);
664	if (ret)
665		goto out;
666
667	dev_set_drvdata(dev, mmc);
668	ret = mmc_add_host(mmc);
669	if (ret)
670		goto out;
671
672	dev_dbg(dev, "IRQ=%d, FIFO is %d bytes\n", irq, host->fifo_width);
673
674	return 0;
675
676out:
677	if (!IS_ERR_OR_NULL(host->dma_chan_tx))
678		dma_release_channel(host->dma_chan_tx);
679	if (!IS_ERR_OR_NULL(host->dma_chan_rx))
680		dma_release_channel(host->dma_chan_rx);
681out_mmc:
682	if (mmc)
683		mmc_free_host(mmc);
684	return ret;
685}
686
687static int moxart_remove(struct platform_device *pdev)
688{
689	struct mmc_host *mmc = dev_get_drvdata(&pdev->dev);
690	struct moxart_host *host = mmc_priv(mmc);
691
692	dev_set_drvdata(&pdev->dev, NULL);
693
694	if (!IS_ERR_OR_NULL(host->dma_chan_tx))
695		dma_release_channel(host->dma_chan_tx);
696	if (!IS_ERR_OR_NULL(host->dma_chan_rx))
697		dma_release_channel(host->dma_chan_rx);
698	mmc_remove_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	mmc_free_host(mmc);
705
706	return 0;
707}
708
709static const struct of_device_id moxart_mmc_match[] = {
710	{ .compatible = "moxa,moxart-mmc" },
711	{ .compatible = "faraday,ftsdc010" },
712	{ }
713};
714MODULE_DEVICE_TABLE(of, moxart_mmc_match);
715
716static struct platform_driver moxart_mmc_driver = {
717	.probe      = moxart_probe,
718	.remove     = moxart_remove,
719	.driver     = {
720		.name		= "mmc-moxart",
721		.probe_type	= PROBE_PREFER_ASYNCHRONOUS,
722		.of_match_table	= moxart_mmc_match,
723	},
724};
725module_platform_driver(moxart_mmc_driver);
726
727MODULE_ALIAS("platform:mmc-moxart");
728MODULE_DESCRIPTION("MOXA ART MMC driver");
729MODULE_LICENSE("GPL v2");
730MODULE_AUTHOR("Jonas Jensen <jonas.jensen@gmail.com>");