xref: /openbmc/linux/drivers/mmc/host/mxcmmc.c (revision 05bcf503)
1 /*
2  *  linux/drivers/mmc/host/mxcmmc.c - Freescale i.MX MMCI driver
3  *
4  *  This is a driver for the SDHC controller found in Freescale MX2/MX3
5  *  SoCs. It is basically the same hardware as found on MX1 (imxmmc.c).
6  *  Unlike the hardware found on MX1, this hardware just works and does
7  *  not need all the quirks found in imxmmc.c, hence the separate driver.
8  *
9  *  Copyright (C) 2008 Sascha Hauer, Pengutronix <s.hauer@pengutronix.de>
10  *  Copyright (C) 2006 Pavel Pisa, PiKRON <ppisa@pikron.com>
11  *
12  *  derived from pxamci.c by Russell King
13  *
14  * This program is free software; you can redistribute it and/or modify
15  * it under the terms of the GNU General Public License version 2 as
16  * published by the Free Software Foundation.
17  *
18  */
19 
20 #include <linux/module.h>
21 #include <linux/init.h>
22 #include <linux/ioport.h>
23 #include <linux/platform_device.h>
24 #include <linux/interrupt.h>
25 #include <linux/irq.h>
26 #include <linux/blkdev.h>
27 #include <linux/dma-mapping.h>
28 #include <linux/mmc/host.h>
29 #include <linux/mmc/card.h>
30 #include <linux/delay.h>
31 #include <linux/clk.h>
32 #include <linux/io.h>
33 #include <linux/gpio.h>
34 #include <linux/regulator/consumer.h>
35 #include <linux/dmaengine.h>
36 #include <linux/types.h>
37 
38 #include <asm/dma.h>
39 #include <asm/irq.h>
40 #include <asm/sizes.h>
41 #include <linux/platform_data/mmc-mxcmmc.h>
42 
43 #include <linux/platform_data/dma-imx.h>
44 #include <mach/hardware.h>
45 
46 #define DRIVER_NAME "mxc-mmc"
47 #define MXCMCI_TIMEOUT_MS 10000
48 
49 #define MMC_REG_STR_STP_CLK		0x00
50 #define MMC_REG_STATUS			0x04
51 #define MMC_REG_CLK_RATE		0x08
52 #define MMC_REG_CMD_DAT_CONT		0x0C
53 #define MMC_REG_RES_TO			0x10
54 #define MMC_REG_READ_TO			0x14
55 #define MMC_REG_BLK_LEN			0x18
56 #define MMC_REG_NOB			0x1C
57 #define MMC_REG_REV_NO			0x20
58 #define MMC_REG_INT_CNTR		0x24
59 #define MMC_REG_CMD			0x28
60 #define MMC_REG_ARG			0x2C
61 #define MMC_REG_RES_FIFO		0x34
62 #define MMC_REG_BUFFER_ACCESS		0x38
63 
64 #define STR_STP_CLK_RESET               (1 << 3)
65 #define STR_STP_CLK_START_CLK           (1 << 1)
66 #define STR_STP_CLK_STOP_CLK            (1 << 0)
67 
68 #define STATUS_CARD_INSERTION		(1 << 31)
69 #define STATUS_CARD_REMOVAL		(1 << 30)
70 #define STATUS_YBUF_EMPTY		(1 << 29)
71 #define STATUS_XBUF_EMPTY		(1 << 28)
72 #define STATUS_YBUF_FULL		(1 << 27)
73 #define STATUS_XBUF_FULL		(1 << 26)
74 #define STATUS_BUF_UND_RUN		(1 << 25)
75 #define STATUS_BUF_OVFL			(1 << 24)
76 #define STATUS_SDIO_INT_ACTIVE		(1 << 14)
77 #define STATUS_END_CMD_RESP		(1 << 13)
78 #define STATUS_WRITE_OP_DONE		(1 << 12)
79 #define STATUS_DATA_TRANS_DONE		(1 << 11)
80 #define STATUS_READ_OP_DONE		(1 << 11)
81 #define STATUS_WR_CRC_ERROR_CODE_MASK	(3 << 10)
82 #define STATUS_CARD_BUS_CLK_RUN		(1 << 8)
83 #define STATUS_BUF_READ_RDY		(1 << 7)
84 #define STATUS_BUF_WRITE_RDY		(1 << 6)
85 #define STATUS_RESP_CRC_ERR		(1 << 5)
86 #define STATUS_CRC_READ_ERR		(1 << 3)
87 #define STATUS_CRC_WRITE_ERR		(1 << 2)
88 #define STATUS_TIME_OUT_RESP		(1 << 1)
89 #define STATUS_TIME_OUT_READ		(1 << 0)
90 #define STATUS_ERR_MASK			0x2f
91 
92 #define CMD_DAT_CONT_CMD_RESP_LONG_OFF	(1 << 12)
93 #define CMD_DAT_CONT_STOP_READWAIT	(1 << 11)
94 #define CMD_DAT_CONT_START_READWAIT	(1 << 10)
95 #define CMD_DAT_CONT_BUS_WIDTH_4	(2 << 8)
96 #define CMD_DAT_CONT_INIT		(1 << 7)
97 #define CMD_DAT_CONT_WRITE		(1 << 4)
98 #define CMD_DAT_CONT_DATA_ENABLE	(1 << 3)
99 #define CMD_DAT_CONT_RESPONSE_48BIT_CRC	(1 << 0)
100 #define CMD_DAT_CONT_RESPONSE_136BIT	(2 << 0)
101 #define CMD_DAT_CONT_RESPONSE_48BIT	(3 << 0)
102 
103 #define INT_SDIO_INT_WKP_EN		(1 << 18)
104 #define INT_CARD_INSERTION_WKP_EN	(1 << 17)
105 #define INT_CARD_REMOVAL_WKP_EN		(1 << 16)
106 #define INT_CARD_INSERTION_EN		(1 << 15)
107 #define INT_CARD_REMOVAL_EN		(1 << 14)
108 #define INT_SDIO_IRQ_EN			(1 << 13)
109 #define INT_DAT0_EN			(1 << 12)
110 #define INT_BUF_READ_EN			(1 << 4)
111 #define INT_BUF_WRITE_EN		(1 << 3)
112 #define INT_END_CMD_RES_EN		(1 << 2)
113 #define INT_WRITE_OP_DONE_EN		(1 << 1)
114 #define INT_READ_OP_EN			(1 << 0)
115 
116 struct mxcmci_host {
117 	struct mmc_host		*mmc;
118 	struct resource		*res;
119 	void __iomem		*base;
120 	int			irq;
121 	int			detect_irq;
122 	struct dma_chan		*dma;
123 	struct dma_async_tx_descriptor *desc;
124 	int			do_dma;
125 	int			default_irq_mask;
126 	int			use_sdio;
127 	unsigned int		power_mode;
128 	struct imxmmc_platform_data *pdata;
129 
130 	struct mmc_request	*req;
131 	struct mmc_command	*cmd;
132 	struct mmc_data		*data;
133 
134 	unsigned int		datasize;
135 	unsigned int		dma_dir;
136 
137 	u16			rev_no;
138 	unsigned int		cmdat;
139 
140 	struct clk		*clk_ipg;
141 	struct clk		*clk_per;
142 
143 	int			clock;
144 
145 	struct work_struct	datawork;
146 	spinlock_t		lock;
147 
148 	struct regulator	*vcc;
149 
150 	int			burstlen;
151 	int			dmareq;
152 	struct dma_slave_config dma_slave_config;
153 	struct imx_dma_data	dma_data;
154 
155 	struct timer_list	watchdog;
156 };
157 
158 static void mxcmci_set_clk_rate(struct mxcmci_host *host, unsigned int clk_ios);
159 
160 static inline void mxcmci_init_ocr(struct mxcmci_host *host)
161 {
162 	host->vcc = regulator_get(mmc_dev(host->mmc), "vmmc");
163 
164 	if (IS_ERR(host->vcc)) {
165 		host->vcc = NULL;
166 	} else {
167 		host->mmc->ocr_avail = mmc_regulator_get_ocrmask(host->vcc);
168 		if (host->pdata && host->pdata->ocr_avail)
169 			dev_warn(mmc_dev(host->mmc),
170 				"pdata->ocr_avail will not be used\n");
171 	}
172 
173 	if (host->vcc == NULL) {
174 		/* fall-back to platform data */
175 		if (host->pdata && host->pdata->ocr_avail)
176 			host->mmc->ocr_avail = host->pdata->ocr_avail;
177 		else
178 			host->mmc->ocr_avail = MMC_VDD_32_33 | MMC_VDD_33_34;
179 	}
180 }
181 
182 static inline void mxcmci_set_power(struct mxcmci_host *host,
183 				    unsigned char power_mode,
184 				    unsigned int vdd)
185 {
186 	if (host->vcc) {
187 		if (power_mode == MMC_POWER_UP)
188 			mmc_regulator_set_ocr(host->mmc, host->vcc, vdd);
189 		else if (power_mode == MMC_POWER_OFF)
190 			mmc_regulator_set_ocr(host->mmc, host->vcc, 0);
191 	}
192 
193 	if (host->pdata && host->pdata->setpower)
194 		host->pdata->setpower(mmc_dev(host->mmc), vdd);
195 }
196 
197 static inline int mxcmci_use_dma(struct mxcmci_host *host)
198 {
199 	return host->do_dma;
200 }
201 
202 static void mxcmci_softreset(struct mxcmci_host *host)
203 {
204 	int i;
205 
206 	dev_dbg(mmc_dev(host->mmc), "mxcmci_softreset\n");
207 
208 	/* reset sequence */
209 	writew(STR_STP_CLK_RESET, host->base + MMC_REG_STR_STP_CLK);
210 	writew(STR_STP_CLK_RESET | STR_STP_CLK_START_CLK,
211 			host->base + MMC_REG_STR_STP_CLK);
212 
213 	for (i = 0; i < 8; i++)
214 		writew(STR_STP_CLK_START_CLK, host->base + MMC_REG_STR_STP_CLK);
215 
216 	writew(0xff, host->base + MMC_REG_RES_TO);
217 }
218 static int mxcmci_setup_dma(struct mmc_host *mmc);
219 
220 static int mxcmci_setup_data(struct mxcmci_host *host, struct mmc_data *data)
221 {
222 	unsigned int nob = data->blocks;
223 	unsigned int blksz = data->blksz;
224 	unsigned int datasize = nob * blksz;
225 	struct scatterlist *sg;
226 	enum dma_transfer_direction slave_dirn;
227 	int i, nents;
228 
229 	if (data->flags & MMC_DATA_STREAM)
230 		nob = 0xffff;
231 
232 	host->data = data;
233 	data->bytes_xfered = 0;
234 
235 	writew(nob, host->base + MMC_REG_NOB);
236 	writew(blksz, host->base + MMC_REG_BLK_LEN);
237 	host->datasize = datasize;
238 
239 	if (!mxcmci_use_dma(host))
240 		return 0;
241 
242 	for_each_sg(data->sg, sg, data->sg_len, i) {
243 		if (sg->offset & 3 || sg->length & 3) {
244 			host->do_dma = 0;
245 			return 0;
246 		}
247 	}
248 
249 	if (data->flags & MMC_DATA_READ) {
250 		host->dma_dir = DMA_FROM_DEVICE;
251 		slave_dirn = DMA_DEV_TO_MEM;
252 	} else {
253 		host->dma_dir = DMA_TO_DEVICE;
254 		slave_dirn = DMA_MEM_TO_DEV;
255 	}
256 
257 	nents = dma_map_sg(host->dma->device->dev, data->sg,
258 				     data->sg_len,  host->dma_dir);
259 	if (nents != data->sg_len)
260 		return -EINVAL;
261 
262 	host->desc = dmaengine_prep_slave_sg(host->dma,
263 		data->sg, data->sg_len, slave_dirn,
264 		DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
265 
266 	if (!host->desc) {
267 		dma_unmap_sg(host->dma->device->dev, data->sg, data->sg_len,
268 				host->dma_dir);
269 		host->do_dma = 0;
270 		return 0; /* Fall back to PIO */
271 	}
272 	wmb();
273 
274 	dmaengine_submit(host->desc);
275 	dma_async_issue_pending(host->dma);
276 
277 	mod_timer(&host->watchdog, jiffies + msecs_to_jiffies(MXCMCI_TIMEOUT_MS));
278 
279 	return 0;
280 }
281 
282 static void mxcmci_cmd_done(struct mxcmci_host *host, unsigned int stat);
283 static void mxcmci_data_done(struct mxcmci_host *host, unsigned int stat);
284 
285 static void mxcmci_dma_callback(void *data)
286 {
287 	struct mxcmci_host *host = data;
288 	u32 stat;
289 
290 	del_timer(&host->watchdog);
291 
292 	stat = readl(host->base + MMC_REG_STATUS);
293 	writel(stat & ~STATUS_DATA_TRANS_DONE, host->base + MMC_REG_STATUS);
294 
295 	dev_dbg(mmc_dev(host->mmc), "%s: 0x%08x\n", __func__, stat);
296 
297 	if (stat & STATUS_READ_OP_DONE)
298 		writel(STATUS_READ_OP_DONE, host->base + MMC_REG_STATUS);
299 
300 	mxcmci_data_done(host, stat);
301 }
302 
303 static int mxcmci_start_cmd(struct mxcmci_host *host, struct mmc_command *cmd,
304 		unsigned int cmdat)
305 {
306 	u32 int_cntr = host->default_irq_mask;
307 	unsigned long flags;
308 
309 	WARN_ON(host->cmd != NULL);
310 	host->cmd = cmd;
311 
312 	switch (mmc_resp_type(cmd)) {
313 	case MMC_RSP_R1: /* short CRC, OPCODE */
314 	case MMC_RSP_R1B:/* short CRC, OPCODE, BUSY */
315 		cmdat |= CMD_DAT_CONT_RESPONSE_48BIT_CRC;
316 		break;
317 	case MMC_RSP_R2: /* long 136 bit + CRC */
318 		cmdat |= CMD_DAT_CONT_RESPONSE_136BIT;
319 		break;
320 	case MMC_RSP_R3: /* short */
321 		cmdat |= CMD_DAT_CONT_RESPONSE_48BIT;
322 		break;
323 	case MMC_RSP_NONE:
324 		break;
325 	default:
326 		dev_err(mmc_dev(host->mmc), "unhandled response type 0x%x\n",
327 				mmc_resp_type(cmd));
328 		cmd->error = -EINVAL;
329 		return -EINVAL;
330 	}
331 
332 	int_cntr = INT_END_CMD_RES_EN;
333 
334 	if (mxcmci_use_dma(host)) {
335 		if (host->dma_dir == DMA_FROM_DEVICE) {
336 			host->desc->callback = mxcmci_dma_callback;
337 			host->desc->callback_param = host;
338 		} else {
339 			int_cntr |= INT_WRITE_OP_DONE_EN;
340 		}
341 	}
342 
343 	spin_lock_irqsave(&host->lock, flags);
344 	if (host->use_sdio)
345 		int_cntr |= INT_SDIO_IRQ_EN;
346 	writel(int_cntr, host->base + MMC_REG_INT_CNTR);
347 	spin_unlock_irqrestore(&host->lock, flags);
348 
349 	writew(cmd->opcode, host->base + MMC_REG_CMD);
350 	writel(cmd->arg, host->base + MMC_REG_ARG);
351 	writew(cmdat, host->base + MMC_REG_CMD_DAT_CONT);
352 
353 	return 0;
354 }
355 
356 static void mxcmci_finish_request(struct mxcmci_host *host,
357 		struct mmc_request *req)
358 {
359 	u32 int_cntr = host->default_irq_mask;
360 	unsigned long flags;
361 
362 	spin_lock_irqsave(&host->lock, flags);
363 	if (host->use_sdio)
364 		int_cntr |= INT_SDIO_IRQ_EN;
365 	writel(int_cntr, host->base + MMC_REG_INT_CNTR);
366 	spin_unlock_irqrestore(&host->lock, flags);
367 
368 	host->req = NULL;
369 	host->cmd = NULL;
370 	host->data = NULL;
371 
372 	mmc_request_done(host->mmc, req);
373 }
374 
375 static int mxcmci_finish_data(struct mxcmci_host *host, unsigned int stat)
376 {
377 	struct mmc_data *data = host->data;
378 	int data_error;
379 
380 	if (mxcmci_use_dma(host))
381 		dma_unmap_sg(host->dma->device->dev, data->sg, data->sg_len,
382 				host->dma_dir);
383 
384 	if (stat & STATUS_ERR_MASK) {
385 		dev_dbg(mmc_dev(host->mmc), "request failed. status: 0x%08x\n",
386 				stat);
387 		if (stat & STATUS_CRC_READ_ERR) {
388 			dev_err(mmc_dev(host->mmc), "%s: -EILSEQ\n", __func__);
389 			data->error = -EILSEQ;
390 		} else if (stat & STATUS_CRC_WRITE_ERR) {
391 			u32 err_code = (stat >> 9) & 0x3;
392 			if (err_code == 2) { /* No CRC response */
393 				dev_err(mmc_dev(host->mmc),
394 					"%s: No CRC -ETIMEDOUT\n", __func__);
395 				data->error = -ETIMEDOUT;
396 			} else {
397 				dev_err(mmc_dev(host->mmc),
398 					"%s: -EILSEQ\n", __func__);
399 				data->error = -EILSEQ;
400 			}
401 		} else if (stat & STATUS_TIME_OUT_READ) {
402 			dev_err(mmc_dev(host->mmc),
403 				"%s: read -ETIMEDOUT\n", __func__);
404 			data->error = -ETIMEDOUT;
405 		} else {
406 			dev_err(mmc_dev(host->mmc), "%s: -EIO\n", __func__);
407 			data->error = -EIO;
408 		}
409 	} else {
410 		data->bytes_xfered = host->datasize;
411 	}
412 
413 	data_error = data->error;
414 
415 	host->data = NULL;
416 
417 	return data_error;
418 }
419 
420 static void mxcmci_read_response(struct mxcmci_host *host, unsigned int stat)
421 {
422 	struct mmc_command *cmd = host->cmd;
423 	int i;
424 	u32 a, b, c;
425 
426 	if (!cmd)
427 		return;
428 
429 	if (stat & STATUS_TIME_OUT_RESP) {
430 		dev_dbg(mmc_dev(host->mmc), "CMD TIMEOUT\n");
431 		cmd->error = -ETIMEDOUT;
432 	} else if (stat & STATUS_RESP_CRC_ERR && cmd->flags & MMC_RSP_CRC) {
433 		dev_dbg(mmc_dev(host->mmc), "cmd crc error\n");
434 		cmd->error = -EILSEQ;
435 	}
436 
437 	if (cmd->flags & MMC_RSP_PRESENT) {
438 		if (cmd->flags & MMC_RSP_136) {
439 			for (i = 0; i < 4; i++) {
440 				a = readw(host->base + MMC_REG_RES_FIFO);
441 				b = readw(host->base + MMC_REG_RES_FIFO);
442 				cmd->resp[i] = a << 16 | b;
443 			}
444 		} else {
445 			a = readw(host->base + MMC_REG_RES_FIFO);
446 			b = readw(host->base + MMC_REG_RES_FIFO);
447 			c = readw(host->base + MMC_REG_RES_FIFO);
448 			cmd->resp[0] = a << 24 | b << 8 | c >> 8;
449 		}
450 	}
451 }
452 
453 static int mxcmci_poll_status(struct mxcmci_host *host, u32 mask)
454 {
455 	u32 stat;
456 	unsigned long timeout = jiffies + HZ;
457 
458 	do {
459 		stat = readl(host->base + MMC_REG_STATUS);
460 		if (stat & STATUS_ERR_MASK)
461 			return stat;
462 		if (time_after(jiffies, timeout)) {
463 			mxcmci_softreset(host);
464 			mxcmci_set_clk_rate(host, host->clock);
465 			return STATUS_TIME_OUT_READ;
466 		}
467 		if (stat & mask)
468 			return 0;
469 		cpu_relax();
470 	} while (1);
471 }
472 
473 static int mxcmci_pull(struct mxcmci_host *host, void *_buf, int bytes)
474 {
475 	unsigned int stat;
476 	u32 *buf = _buf;
477 
478 	while (bytes > 3) {
479 		stat = mxcmci_poll_status(host,
480 				STATUS_BUF_READ_RDY | STATUS_READ_OP_DONE);
481 		if (stat)
482 			return stat;
483 		*buf++ = readl(host->base + MMC_REG_BUFFER_ACCESS);
484 		bytes -= 4;
485 	}
486 
487 	if (bytes) {
488 		u8 *b = (u8 *)buf;
489 		u32 tmp;
490 
491 		stat = mxcmci_poll_status(host,
492 				STATUS_BUF_READ_RDY | STATUS_READ_OP_DONE);
493 		if (stat)
494 			return stat;
495 		tmp = readl(host->base + MMC_REG_BUFFER_ACCESS);
496 		memcpy(b, &tmp, bytes);
497 	}
498 
499 	return 0;
500 }
501 
502 static int mxcmci_push(struct mxcmci_host *host, void *_buf, int bytes)
503 {
504 	unsigned int stat;
505 	u32 *buf = _buf;
506 
507 	while (bytes > 3) {
508 		stat = mxcmci_poll_status(host, STATUS_BUF_WRITE_RDY);
509 		if (stat)
510 			return stat;
511 		writel(*buf++, host->base + MMC_REG_BUFFER_ACCESS);
512 		bytes -= 4;
513 	}
514 
515 	if (bytes) {
516 		u8 *b = (u8 *)buf;
517 		u32 tmp;
518 
519 		stat = mxcmci_poll_status(host, STATUS_BUF_WRITE_RDY);
520 		if (stat)
521 			return stat;
522 
523 		memcpy(&tmp, b, bytes);
524 		writel(tmp, host->base + MMC_REG_BUFFER_ACCESS);
525 	}
526 
527 	stat = mxcmci_poll_status(host, STATUS_BUF_WRITE_RDY);
528 	if (stat)
529 		return stat;
530 
531 	return 0;
532 }
533 
534 static int mxcmci_transfer_data(struct mxcmci_host *host)
535 {
536 	struct mmc_data *data = host->req->data;
537 	struct scatterlist *sg;
538 	int stat, i;
539 
540 	host->data = data;
541 	host->datasize = 0;
542 
543 	if (data->flags & MMC_DATA_READ) {
544 		for_each_sg(data->sg, sg, data->sg_len, i) {
545 			stat = mxcmci_pull(host, sg_virt(sg), sg->length);
546 			if (stat)
547 				return stat;
548 			host->datasize += sg->length;
549 		}
550 	} else {
551 		for_each_sg(data->sg, sg, data->sg_len, i) {
552 			stat = mxcmci_push(host, sg_virt(sg), sg->length);
553 			if (stat)
554 				return stat;
555 			host->datasize += sg->length;
556 		}
557 		stat = mxcmci_poll_status(host, STATUS_WRITE_OP_DONE);
558 		if (stat)
559 			return stat;
560 	}
561 	return 0;
562 }
563 
564 static void mxcmci_datawork(struct work_struct *work)
565 {
566 	struct mxcmci_host *host = container_of(work, struct mxcmci_host,
567 						  datawork);
568 	int datastat = mxcmci_transfer_data(host);
569 
570 	writel(STATUS_READ_OP_DONE | STATUS_WRITE_OP_DONE,
571 		host->base + MMC_REG_STATUS);
572 	mxcmci_finish_data(host, datastat);
573 
574 	if (host->req->stop) {
575 		if (mxcmci_start_cmd(host, host->req->stop, 0)) {
576 			mxcmci_finish_request(host, host->req);
577 			return;
578 		}
579 	} else {
580 		mxcmci_finish_request(host, host->req);
581 	}
582 }
583 
584 static void mxcmci_data_done(struct mxcmci_host *host, unsigned int stat)
585 {
586 	struct mmc_data *data = host->data;
587 	int data_error;
588 
589 	if (!data)
590 		return;
591 
592 	data_error = mxcmci_finish_data(host, stat);
593 
594 	mxcmci_read_response(host, stat);
595 	host->cmd = NULL;
596 
597 	if (host->req->stop) {
598 		if (mxcmci_start_cmd(host, host->req->stop, 0)) {
599 			mxcmci_finish_request(host, host->req);
600 			return;
601 		}
602 	} else {
603 		mxcmci_finish_request(host, host->req);
604 	}
605 }
606 
607 static void mxcmci_cmd_done(struct mxcmci_host *host, unsigned int stat)
608 {
609 	mxcmci_read_response(host, stat);
610 	host->cmd = NULL;
611 
612 	if (!host->data && host->req) {
613 		mxcmci_finish_request(host, host->req);
614 		return;
615 	}
616 
617 	/* For the DMA case the DMA engine handles the data transfer
618 	 * automatically. For non DMA we have to do it ourselves.
619 	 * Don't do it in interrupt context though.
620 	 */
621 	if (!mxcmci_use_dma(host) && host->data)
622 		schedule_work(&host->datawork);
623 
624 }
625 
626 static irqreturn_t mxcmci_irq(int irq, void *devid)
627 {
628 	struct mxcmci_host *host = devid;
629 	unsigned long flags;
630 	bool sdio_irq;
631 	u32 stat;
632 
633 	stat = readl(host->base + MMC_REG_STATUS);
634 	writel(stat & ~(STATUS_SDIO_INT_ACTIVE | STATUS_DATA_TRANS_DONE |
635 			STATUS_WRITE_OP_DONE), host->base + MMC_REG_STATUS);
636 
637 	dev_dbg(mmc_dev(host->mmc), "%s: 0x%08x\n", __func__, stat);
638 
639 	spin_lock_irqsave(&host->lock, flags);
640 	sdio_irq = (stat & STATUS_SDIO_INT_ACTIVE) && host->use_sdio;
641 	spin_unlock_irqrestore(&host->lock, flags);
642 
643 	if (mxcmci_use_dma(host) &&
644 	    (stat & (STATUS_READ_OP_DONE | STATUS_WRITE_OP_DONE)))
645 		writel(STATUS_READ_OP_DONE | STATUS_WRITE_OP_DONE,
646 			host->base + MMC_REG_STATUS);
647 
648 	if (sdio_irq) {
649 		writel(STATUS_SDIO_INT_ACTIVE, host->base + MMC_REG_STATUS);
650 		mmc_signal_sdio_irq(host->mmc);
651 	}
652 
653 	if (stat & STATUS_END_CMD_RESP)
654 		mxcmci_cmd_done(host, stat);
655 
656 	if (mxcmci_use_dma(host) &&
657 		  (stat & (STATUS_DATA_TRANS_DONE | STATUS_WRITE_OP_DONE))) {
658 		del_timer(&host->watchdog);
659 		mxcmci_data_done(host, stat);
660 	}
661 
662 	if (host->default_irq_mask &&
663 		  (stat & (STATUS_CARD_INSERTION | STATUS_CARD_REMOVAL)))
664 		mmc_detect_change(host->mmc, msecs_to_jiffies(200));
665 
666 	return IRQ_HANDLED;
667 }
668 
669 static void mxcmci_request(struct mmc_host *mmc, struct mmc_request *req)
670 {
671 	struct mxcmci_host *host = mmc_priv(mmc);
672 	unsigned int cmdat = host->cmdat;
673 	int error;
674 
675 	WARN_ON(host->req != NULL);
676 
677 	host->req = req;
678 	host->cmdat &= ~CMD_DAT_CONT_INIT;
679 
680 	if (host->dma)
681 		host->do_dma = 1;
682 
683 	if (req->data) {
684 		error = mxcmci_setup_data(host, req->data);
685 		if (error) {
686 			req->cmd->error = error;
687 			goto out;
688 		}
689 
690 
691 		cmdat |= CMD_DAT_CONT_DATA_ENABLE;
692 
693 		if (req->data->flags & MMC_DATA_WRITE)
694 			cmdat |= CMD_DAT_CONT_WRITE;
695 	}
696 
697 	error = mxcmci_start_cmd(host, req->cmd, cmdat);
698 
699 out:
700 	if (error)
701 		mxcmci_finish_request(host, req);
702 }
703 
704 static void mxcmci_set_clk_rate(struct mxcmci_host *host, unsigned int clk_ios)
705 {
706 	unsigned int divider;
707 	int prescaler = 0;
708 	unsigned int clk_in = clk_get_rate(host->clk_per);
709 
710 	while (prescaler <= 0x800) {
711 		for (divider = 1; divider <= 0xF; divider++) {
712 			int x;
713 
714 			x = (clk_in / (divider + 1));
715 
716 			if (prescaler)
717 				x /= (prescaler * 2);
718 
719 			if (x <= clk_ios)
720 				break;
721 		}
722 		if (divider < 0x10)
723 			break;
724 
725 		if (prescaler == 0)
726 			prescaler = 1;
727 		else
728 			prescaler <<= 1;
729 	}
730 
731 	writew((prescaler << 4) | divider, host->base + MMC_REG_CLK_RATE);
732 
733 	dev_dbg(mmc_dev(host->mmc), "scaler: %d divider: %d in: %d out: %d\n",
734 			prescaler, divider, clk_in, clk_ios);
735 }
736 
737 static int mxcmci_setup_dma(struct mmc_host *mmc)
738 {
739 	struct mxcmci_host *host = mmc_priv(mmc);
740 	struct dma_slave_config *config = &host->dma_slave_config;
741 
742 	config->dst_addr = host->res->start + MMC_REG_BUFFER_ACCESS;
743 	config->src_addr = host->res->start + MMC_REG_BUFFER_ACCESS;
744 	config->dst_addr_width = 4;
745 	config->src_addr_width = 4;
746 	config->dst_maxburst = host->burstlen;
747 	config->src_maxburst = host->burstlen;
748 	config->device_fc = false;
749 
750 	return dmaengine_slave_config(host->dma, config);
751 }
752 
753 static void mxcmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
754 {
755 	struct mxcmci_host *host = mmc_priv(mmc);
756 	int burstlen, ret;
757 
758 	/*
759 	 * use burstlen of 64 (16 words) in 4 bit mode (--> reg value  0)
760 	 * use burstlen of 16 (4 words) in 1 bit mode (--> reg value 16)
761 	 */
762 	if (ios->bus_width == MMC_BUS_WIDTH_4)
763 		burstlen = 16;
764 	else
765 		burstlen = 4;
766 
767 	if (mxcmci_use_dma(host) && burstlen != host->burstlen) {
768 		host->burstlen = burstlen;
769 		ret = mxcmci_setup_dma(mmc);
770 		if (ret) {
771 			dev_err(mmc_dev(host->mmc),
772 				"failed to config DMA channel. Falling back to PIO\n");
773 			dma_release_channel(host->dma);
774 			host->do_dma = 0;
775 			host->dma = NULL;
776 		}
777 	}
778 
779 	if (ios->bus_width == MMC_BUS_WIDTH_4)
780 		host->cmdat |= CMD_DAT_CONT_BUS_WIDTH_4;
781 	else
782 		host->cmdat &= ~CMD_DAT_CONT_BUS_WIDTH_4;
783 
784 	if (host->power_mode != ios->power_mode) {
785 		mxcmci_set_power(host, ios->power_mode, ios->vdd);
786 		host->power_mode = ios->power_mode;
787 
788 		if (ios->power_mode == MMC_POWER_ON)
789 			host->cmdat |= CMD_DAT_CONT_INIT;
790 	}
791 
792 	if (ios->clock) {
793 		mxcmci_set_clk_rate(host, ios->clock);
794 		writew(STR_STP_CLK_START_CLK, host->base + MMC_REG_STR_STP_CLK);
795 	} else {
796 		writew(STR_STP_CLK_STOP_CLK, host->base + MMC_REG_STR_STP_CLK);
797 	}
798 
799 	host->clock = ios->clock;
800 }
801 
802 static irqreturn_t mxcmci_detect_irq(int irq, void *data)
803 {
804 	struct mmc_host *mmc = data;
805 
806 	dev_dbg(mmc_dev(mmc), "%s\n", __func__);
807 
808 	mmc_detect_change(mmc, msecs_to_jiffies(250));
809 	return IRQ_HANDLED;
810 }
811 
812 static int mxcmci_get_ro(struct mmc_host *mmc)
813 {
814 	struct mxcmci_host *host = mmc_priv(mmc);
815 
816 	if (host->pdata && host->pdata->get_ro)
817 		return !!host->pdata->get_ro(mmc_dev(mmc));
818 	/*
819 	 * Board doesn't support read only detection; let the mmc core
820 	 * decide what to do.
821 	 */
822 	return -ENOSYS;
823 }
824 
825 static void mxcmci_enable_sdio_irq(struct mmc_host *mmc, int enable)
826 {
827 	struct mxcmci_host *host = mmc_priv(mmc);
828 	unsigned long flags;
829 	u32 int_cntr;
830 
831 	spin_lock_irqsave(&host->lock, flags);
832 	host->use_sdio = enable;
833 	int_cntr = readl(host->base + MMC_REG_INT_CNTR);
834 
835 	if (enable)
836 		int_cntr |= INT_SDIO_IRQ_EN;
837 	else
838 		int_cntr &= ~INT_SDIO_IRQ_EN;
839 
840 	writel(int_cntr, host->base + MMC_REG_INT_CNTR);
841 	spin_unlock_irqrestore(&host->lock, flags);
842 }
843 
844 static void mxcmci_init_card(struct mmc_host *host, struct mmc_card *card)
845 {
846 	/*
847 	 * MX3 SoCs have a silicon bug which corrupts CRC calculation of
848 	 * multi-block transfers when connected SDIO peripheral doesn't
849 	 * drive the BUSY line as required by the specs.
850 	 * One way to prevent this is to only allow 1-bit transfers.
851 	 */
852 
853 	if (cpu_is_mx3() && card->type == MMC_TYPE_SDIO)
854 		host->caps &= ~MMC_CAP_4_BIT_DATA;
855 	else
856 		host->caps |= MMC_CAP_4_BIT_DATA;
857 }
858 
859 static bool filter(struct dma_chan *chan, void *param)
860 {
861 	struct mxcmci_host *host = param;
862 
863 	if (!imx_dma_is_general_purpose(chan))
864 		return false;
865 
866 	chan->private = &host->dma_data;
867 
868 	return true;
869 }
870 
871 static void mxcmci_watchdog(unsigned long data)
872 {
873 	struct mmc_host *mmc = (struct mmc_host *)data;
874 	struct mxcmci_host *host = mmc_priv(mmc);
875 	struct mmc_request *req = host->req;
876 	unsigned int stat = readl(host->base + MMC_REG_STATUS);
877 
878 	if (host->dma_dir == DMA_FROM_DEVICE) {
879 		dmaengine_terminate_all(host->dma);
880 		dev_err(mmc_dev(host->mmc),
881 			"%s: read time out (status = 0x%08x)\n",
882 			__func__, stat);
883 	} else {
884 		dev_err(mmc_dev(host->mmc),
885 			"%s: write time out (status = 0x%08x)\n",
886 			__func__, stat);
887 		mxcmci_softreset(host);
888 	}
889 
890 	/* Mark transfer as erroneus and inform the upper layers */
891 
892 	host->data->error = -ETIMEDOUT;
893 	host->req = NULL;
894 	host->cmd = NULL;
895 	host->data = NULL;
896 	mmc_request_done(host->mmc, req);
897 }
898 
899 static const struct mmc_host_ops mxcmci_ops = {
900 	.request		= mxcmci_request,
901 	.set_ios		= mxcmci_set_ios,
902 	.get_ro			= mxcmci_get_ro,
903 	.enable_sdio_irq	= mxcmci_enable_sdio_irq,
904 	.init_card		= mxcmci_init_card,
905 };
906 
907 static int mxcmci_probe(struct platform_device *pdev)
908 {
909 	struct mmc_host *mmc;
910 	struct mxcmci_host *host = NULL;
911 	struct resource *iores, *r;
912 	int ret = 0, irq;
913 	dma_cap_mask_t mask;
914 
915 	pr_info("i.MX SDHC driver\n");
916 
917 	iores = platform_get_resource(pdev, IORESOURCE_MEM, 0);
918 	irq = platform_get_irq(pdev, 0);
919 	if (!iores || irq < 0)
920 		return -EINVAL;
921 
922 	r = request_mem_region(iores->start, resource_size(iores), pdev->name);
923 	if (!r)
924 		return -EBUSY;
925 
926 	mmc = mmc_alloc_host(sizeof(struct mxcmci_host), &pdev->dev);
927 	if (!mmc) {
928 		ret = -ENOMEM;
929 		goto out_release_mem;
930 	}
931 
932 	mmc->ops = &mxcmci_ops;
933 	mmc->caps = MMC_CAP_4_BIT_DATA | MMC_CAP_SDIO_IRQ;
934 
935 	/* MMC core transfer sizes tunable parameters */
936 	mmc->max_segs = 64;
937 	mmc->max_blk_size = 2048;
938 	mmc->max_blk_count = 65535;
939 	mmc->max_req_size = mmc->max_blk_size * mmc->max_blk_count;
940 	mmc->max_seg_size = mmc->max_req_size;
941 
942 	host = mmc_priv(mmc);
943 	host->base = ioremap(r->start, resource_size(r));
944 	if (!host->base) {
945 		ret = -ENOMEM;
946 		goto out_free;
947 	}
948 
949 	host->mmc = mmc;
950 	host->pdata = pdev->dev.platform_data;
951 	spin_lock_init(&host->lock);
952 
953 	mxcmci_init_ocr(host);
954 
955 	if (host->pdata && host->pdata->dat3_card_detect)
956 		host->default_irq_mask =
957 			INT_CARD_INSERTION_EN | INT_CARD_REMOVAL_EN;
958 	else
959 		host->default_irq_mask = 0;
960 
961 	host->res = r;
962 	host->irq = irq;
963 
964 	host->clk_ipg = devm_clk_get(&pdev->dev, "ipg");
965 	if (IS_ERR(host->clk_ipg)) {
966 		ret = PTR_ERR(host->clk_ipg);
967 		goto out_iounmap;
968 	}
969 
970 	host->clk_per = devm_clk_get(&pdev->dev, "per");
971 	if (IS_ERR(host->clk_per)) {
972 		ret = PTR_ERR(host->clk_per);
973 		goto out_iounmap;
974 	}
975 
976 	clk_prepare_enable(host->clk_per);
977 	clk_prepare_enable(host->clk_ipg);
978 
979 	mxcmci_softreset(host);
980 
981 	host->rev_no = readw(host->base + MMC_REG_REV_NO);
982 	if (host->rev_no != 0x400) {
983 		ret = -ENODEV;
984 		dev_err(mmc_dev(host->mmc), "wrong rev.no. 0x%08x. aborting.\n",
985 			host->rev_no);
986 		goto out_clk_put;
987 	}
988 
989 	mmc->f_min = clk_get_rate(host->clk_per) >> 16;
990 	mmc->f_max = clk_get_rate(host->clk_per) >> 1;
991 
992 	/* recommended in data sheet */
993 	writew(0x2db4, host->base + MMC_REG_READ_TO);
994 
995 	writel(host->default_irq_mask, host->base + MMC_REG_INT_CNTR);
996 
997 	r = platform_get_resource(pdev, IORESOURCE_DMA, 0);
998 	if (r) {
999 		host->dmareq = r->start;
1000 		host->dma_data.peripheral_type = IMX_DMATYPE_SDHC;
1001 		host->dma_data.priority = DMA_PRIO_LOW;
1002 		host->dma_data.dma_request = host->dmareq;
1003 		dma_cap_zero(mask);
1004 		dma_cap_set(DMA_SLAVE, mask);
1005 		host->dma = dma_request_channel(mask, filter, host);
1006 		if (host->dma)
1007 			mmc->max_seg_size = dma_get_max_seg_size(
1008 					host->dma->device->dev);
1009 	}
1010 
1011 	if (!host->dma)
1012 		dev_info(mmc_dev(host->mmc), "dma not available. Using PIO\n");
1013 
1014 	INIT_WORK(&host->datawork, mxcmci_datawork);
1015 
1016 	ret = request_irq(host->irq, mxcmci_irq, 0, DRIVER_NAME, host);
1017 	if (ret)
1018 		goto out_free_dma;
1019 
1020 	platform_set_drvdata(pdev, mmc);
1021 
1022 	if (host->pdata && host->pdata->init) {
1023 		ret = host->pdata->init(&pdev->dev, mxcmci_detect_irq,
1024 				host->mmc);
1025 		if (ret)
1026 			goto out_free_irq;
1027 	}
1028 
1029 	mmc_add_host(mmc);
1030 
1031 	init_timer(&host->watchdog);
1032 	host->watchdog.function = &mxcmci_watchdog;
1033 	host->watchdog.data = (unsigned long)mmc;
1034 
1035 	return 0;
1036 
1037 out_free_irq:
1038 	free_irq(host->irq, host);
1039 out_free_dma:
1040 	if (host->dma)
1041 		dma_release_channel(host->dma);
1042 out_clk_put:
1043 	clk_disable_unprepare(host->clk_per);
1044 	clk_disable_unprepare(host->clk_ipg);
1045 out_iounmap:
1046 	iounmap(host->base);
1047 out_free:
1048 	mmc_free_host(mmc);
1049 out_release_mem:
1050 	release_mem_region(iores->start, resource_size(iores));
1051 	return ret;
1052 }
1053 
1054 static int mxcmci_remove(struct platform_device *pdev)
1055 {
1056 	struct mmc_host *mmc = platform_get_drvdata(pdev);
1057 	struct mxcmci_host *host = mmc_priv(mmc);
1058 
1059 	platform_set_drvdata(pdev, NULL);
1060 
1061 	mmc_remove_host(mmc);
1062 
1063 	if (host->vcc)
1064 		regulator_put(host->vcc);
1065 
1066 	if (host->pdata && host->pdata->exit)
1067 		host->pdata->exit(&pdev->dev, mmc);
1068 
1069 	free_irq(host->irq, host);
1070 	iounmap(host->base);
1071 
1072 	if (host->dma)
1073 		dma_release_channel(host->dma);
1074 
1075 	clk_disable_unprepare(host->clk_per);
1076 	clk_disable_unprepare(host->clk_ipg);
1077 
1078 	release_mem_region(host->res->start, resource_size(host->res));
1079 
1080 	mmc_free_host(mmc);
1081 
1082 	return 0;
1083 }
1084 
1085 #ifdef CONFIG_PM
1086 static int mxcmci_suspend(struct device *dev)
1087 {
1088 	struct mmc_host *mmc = dev_get_drvdata(dev);
1089 	struct mxcmci_host *host = mmc_priv(mmc);
1090 	int ret = 0;
1091 
1092 	if (mmc)
1093 		ret = mmc_suspend_host(mmc);
1094 	clk_disable_unprepare(host->clk_per);
1095 	clk_disable_unprepare(host->clk_ipg);
1096 
1097 	return ret;
1098 }
1099 
1100 static int mxcmci_resume(struct device *dev)
1101 {
1102 	struct mmc_host *mmc = dev_get_drvdata(dev);
1103 	struct mxcmci_host *host = mmc_priv(mmc);
1104 	int ret = 0;
1105 
1106 	clk_prepare_enable(host->clk_per);
1107 	clk_prepare_enable(host->clk_ipg);
1108 	if (mmc)
1109 		ret = mmc_resume_host(mmc);
1110 
1111 	return ret;
1112 }
1113 
1114 static const struct dev_pm_ops mxcmci_pm_ops = {
1115 	.suspend	= mxcmci_suspend,
1116 	.resume		= mxcmci_resume,
1117 };
1118 #endif
1119 
1120 static struct platform_driver mxcmci_driver = {
1121 	.probe		= mxcmci_probe,
1122 	.remove		= mxcmci_remove,
1123 	.driver		= {
1124 		.name		= DRIVER_NAME,
1125 		.owner		= THIS_MODULE,
1126 #ifdef CONFIG_PM
1127 		.pm	= &mxcmci_pm_ops,
1128 #endif
1129 	}
1130 };
1131 
1132 module_platform_driver(mxcmci_driver);
1133 
1134 MODULE_DESCRIPTION("i.MX Multimedia Card Interface Driver");
1135 MODULE_AUTHOR("Sascha Hauer, Pengutronix");
1136 MODULE_LICENSE("GPL");
1137 MODULE_ALIAS("platform:mxc-mmc");
1138