xref: /openbmc/linux/drivers/mmc/host/atmel-mci.c (revision 545e4006)
1 /*
2  * Atmel MultiMedia Card Interface driver
3  *
4  * Copyright (C) 2004-2008 Atmel Corporation
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 as
8  * published by the Free Software Foundation.
9  */
10 #include <linux/blkdev.h>
11 #include <linux/clk.h>
12 #include <linux/device.h>
13 #include <linux/init.h>
14 #include <linux/interrupt.h>
15 #include <linux/ioport.h>
16 #include <linux/module.h>
17 #include <linux/platform_device.h>
18 #include <linux/scatterlist.h>
19 
20 #include <linux/mmc/host.h>
21 
22 #include <asm/atmel-mci.h>
23 #include <asm/io.h>
24 #include <asm/unaligned.h>
25 
26 #include <asm/arch/board.h>
27 #include <asm/arch/gpio.h>
28 
29 #include "atmel-mci-regs.h"
30 
31 #define ATMCI_DATA_ERROR_FLAGS	(MCI_DCRCE | MCI_DTOE | MCI_OVRE | MCI_UNRE)
32 
33 enum {
34 	EVENT_CMD_COMPLETE = 0,
35 	EVENT_DATA_ERROR,
36 	EVENT_DATA_COMPLETE,
37 	EVENT_STOP_SENT,
38 	EVENT_STOP_COMPLETE,
39 	EVENT_XFER_COMPLETE,
40 };
41 
42 struct atmel_mci {
43 	struct mmc_host		*mmc;
44 	void __iomem		*regs;
45 
46 	struct scatterlist	*sg;
47 	unsigned int		pio_offset;
48 
49 	struct mmc_request	*mrq;
50 	struct mmc_command	*cmd;
51 	struct mmc_data		*data;
52 
53 	u32			cmd_status;
54 	u32			data_status;
55 	u32			stop_status;
56 	u32			stop_cmdr;
57 
58 	u32			mode_reg;
59 	u32			sdc_reg;
60 
61 	struct tasklet_struct	tasklet;
62 	unsigned long		pending_events;
63 	unsigned long		completed_events;
64 
65 	int			present;
66 	int			detect_pin;
67 	int			wp_pin;
68 
69 	/* For detect pin debouncing */
70 	struct timer_list	detect_timer;
71 
72 	unsigned long		bus_hz;
73 	unsigned long		mapbase;
74 	struct clk		*mck;
75 	struct platform_device	*pdev;
76 };
77 
78 #define atmci_is_completed(host, event)				\
79 	test_bit(event, &host->completed_events)
80 #define atmci_test_and_clear_pending(host, event)		\
81 	test_and_clear_bit(event, &host->pending_events)
82 #define atmci_test_and_set_completed(host, event)		\
83 	test_and_set_bit(event, &host->completed_events)
84 #define atmci_set_completed(host, event)			\
85 	set_bit(event, &host->completed_events)
86 #define atmci_set_pending(host, event)				\
87 	set_bit(event, &host->pending_events)
88 #define atmci_clear_pending(host, event)			\
89 	clear_bit(event, &host->pending_events)
90 
91 
92 static void atmci_enable(struct atmel_mci *host)
93 {
94 	clk_enable(host->mck);
95 	mci_writel(host, CR, MCI_CR_MCIEN);
96 	mci_writel(host, MR, host->mode_reg);
97 	mci_writel(host, SDCR, host->sdc_reg);
98 }
99 
100 static void atmci_disable(struct atmel_mci *host)
101 {
102 	mci_writel(host, CR, MCI_CR_SWRST);
103 
104 	/* Stall until write is complete, then disable the bus clock */
105 	mci_readl(host, SR);
106 	clk_disable(host->mck);
107 }
108 
109 static inline unsigned int ns_to_clocks(struct atmel_mci *host,
110 					unsigned int ns)
111 {
112 	return (ns * (host->bus_hz / 1000000) + 999) / 1000;
113 }
114 
115 static void atmci_set_timeout(struct atmel_mci *host,
116 			      struct mmc_data *data)
117 {
118 	static unsigned	dtomul_to_shift[] = {
119 		0, 4, 7, 8, 10, 12, 16, 20
120 	};
121 	unsigned	timeout;
122 	unsigned	dtocyc;
123 	unsigned	dtomul;
124 
125 	timeout = ns_to_clocks(host, data->timeout_ns) + data->timeout_clks;
126 
127 	for (dtomul = 0; dtomul < 8; dtomul++) {
128 		unsigned shift = dtomul_to_shift[dtomul];
129 		dtocyc = (timeout + (1 << shift) - 1) >> shift;
130 		if (dtocyc < 15)
131 			break;
132 	}
133 
134 	if (dtomul >= 8) {
135 		dtomul = 7;
136 		dtocyc = 15;
137 	}
138 
139 	dev_vdbg(&host->mmc->class_dev, "setting timeout to %u cycles\n",
140 			dtocyc << dtomul_to_shift[dtomul]);
141 	mci_writel(host, DTOR, (MCI_DTOMUL(dtomul) | MCI_DTOCYC(dtocyc)));
142 }
143 
144 /*
145  * Return mask with command flags to be enabled for this command.
146  */
147 static u32 atmci_prepare_command(struct mmc_host *mmc,
148 				 struct mmc_command *cmd)
149 {
150 	struct mmc_data	*data;
151 	u32		cmdr;
152 
153 	cmd->error = -EINPROGRESS;
154 
155 	cmdr = MCI_CMDR_CMDNB(cmd->opcode);
156 
157 	if (cmd->flags & MMC_RSP_PRESENT) {
158 		if (cmd->flags & MMC_RSP_136)
159 			cmdr |= MCI_CMDR_RSPTYP_136BIT;
160 		else
161 			cmdr |= MCI_CMDR_RSPTYP_48BIT;
162 	}
163 
164 	/*
165 	 * This should really be MAXLAT_5 for CMD2 and ACMD41, but
166 	 * it's too difficult to determine whether this is an ACMD or
167 	 * not. Better make it 64.
168 	 */
169 	cmdr |= MCI_CMDR_MAXLAT_64CYC;
170 
171 	if (mmc->ios.bus_mode == MMC_BUSMODE_OPENDRAIN)
172 		cmdr |= MCI_CMDR_OPDCMD;
173 
174 	data = cmd->data;
175 	if (data) {
176 		cmdr |= MCI_CMDR_START_XFER;
177 		if (data->flags & MMC_DATA_STREAM)
178 			cmdr |= MCI_CMDR_STREAM;
179 		else if (data->blocks > 1)
180 			cmdr |= MCI_CMDR_MULTI_BLOCK;
181 		else
182 			cmdr |= MCI_CMDR_BLOCK;
183 
184 		if (data->flags & MMC_DATA_READ)
185 			cmdr |= MCI_CMDR_TRDIR_READ;
186 	}
187 
188 	return cmdr;
189 }
190 
191 static void atmci_start_command(struct atmel_mci *host,
192 				struct mmc_command *cmd,
193 				u32 cmd_flags)
194 {
195 	/* Must read host->cmd after testing event flags */
196 	smp_rmb();
197 	WARN_ON(host->cmd);
198 	host->cmd = cmd;
199 
200 	dev_vdbg(&host->mmc->class_dev,
201 			"start command: ARGR=0x%08x CMDR=0x%08x\n",
202 			cmd->arg, cmd_flags);
203 
204 	mci_writel(host, ARGR, cmd->arg);
205 	mci_writel(host, CMDR, cmd_flags);
206 }
207 
208 static void send_stop_cmd(struct mmc_host *mmc, struct mmc_data *data)
209 {
210 	struct atmel_mci *host = mmc_priv(mmc);
211 
212 	atmci_start_command(host, data->stop, host->stop_cmdr);
213 	mci_writel(host, IER, MCI_CMDRDY);
214 }
215 
216 static void atmci_request_end(struct mmc_host *mmc, struct mmc_request *mrq)
217 {
218 	struct atmel_mci *host = mmc_priv(mmc);
219 
220 	WARN_ON(host->cmd || host->data);
221 	host->mrq = NULL;
222 
223 	atmci_disable(host);
224 
225 	mmc_request_done(mmc, mrq);
226 }
227 
228 /*
229  * Returns a mask of interrupt flags to be enabled after the whole
230  * request has been prepared.
231  */
232 static u32 atmci_submit_data(struct mmc_host *mmc, struct mmc_data *data)
233 {
234 	struct atmel_mci	*host = mmc_priv(mmc);
235 	u32			iflags;
236 
237 	data->error = -EINPROGRESS;
238 
239 	WARN_ON(host->data);
240 	host->sg = NULL;
241 	host->data = data;
242 
243 	mci_writel(host, BLKR, MCI_BCNT(data->blocks)
244 			| MCI_BLKLEN(data->blksz));
245 	dev_vdbg(&mmc->class_dev, "BLKR=0x%08x\n",
246 			MCI_BCNT(data->blocks) | MCI_BLKLEN(data->blksz));
247 
248 	iflags = ATMCI_DATA_ERROR_FLAGS;
249 	host->sg = data->sg;
250 	host->pio_offset = 0;
251 	if (data->flags & MMC_DATA_READ)
252 		iflags |= MCI_RXRDY;
253 	else
254 		iflags |= MCI_TXRDY;
255 
256 	return iflags;
257 }
258 
259 static void atmci_request(struct mmc_host *mmc, struct mmc_request *mrq)
260 {
261 	struct atmel_mci	*host = mmc_priv(mmc);
262 	struct mmc_data		*data;
263 	struct mmc_command	*cmd;
264 	u32			iflags;
265 	u32			cmdflags = 0;
266 
267 	iflags = mci_readl(host, IMR);
268 	if (iflags)
269 		dev_warn(&mmc->class_dev, "WARNING: IMR=0x%08x\n",
270 				mci_readl(host, IMR));
271 
272 	WARN_ON(host->mrq != NULL);
273 
274 	/*
275 	 * We may "know" the card is gone even though there's still an
276 	 * electrical connection. If so, we really need to communicate
277 	 * this to the MMC core since there won't be any more
278 	 * interrupts as the card is completely removed. Otherwise,
279 	 * the MMC core might believe the card is still there even
280 	 * though the card was just removed very slowly.
281 	 */
282 	if (!host->present) {
283 		mrq->cmd->error = -ENOMEDIUM;
284 		mmc_request_done(mmc, mrq);
285 		return;
286 	}
287 
288 	host->mrq = mrq;
289 	host->pending_events = 0;
290 	host->completed_events = 0;
291 
292 	atmci_enable(host);
293 
294 	/* We don't support multiple blocks of weird lengths. */
295 	data = mrq->data;
296 	if (data) {
297 		if (data->blocks > 1 && data->blksz & 3)
298 			goto fail;
299 		atmci_set_timeout(host, data);
300 	}
301 
302 	iflags = MCI_CMDRDY;
303 	cmd = mrq->cmd;
304 	cmdflags = atmci_prepare_command(mmc, cmd);
305 	atmci_start_command(host, cmd, cmdflags);
306 
307 	if (data)
308 		iflags |= atmci_submit_data(mmc, data);
309 
310 	if (mrq->stop) {
311 		host->stop_cmdr = atmci_prepare_command(mmc, mrq->stop);
312 		host->stop_cmdr |= MCI_CMDR_STOP_XFER;
313 		if (!(data->flags & MMC_DATA_WRITE))
314 			host->stop_cmdr |= MCI_CMDR_TRDIR_READ;
315 		if (data->flags & MMC_DATA_STREAM)
316 			host->stop_cmdr |= MCI_CMDR_STREAM;
317 		else
318 			host->stop_cmdr |= MCI_CMDR_MULTI_BLOCK;
319 	}
320 
321 	/*
322 	 * We could have enabled interrupts earlier, but I suspect
323 	 * that would open up a nice can of interesting race
324 	 * conditions (e.g. command and data complete, but stop not
325 	 * prepared yet.)
326 	 */
327 	mci_writel(host, IER, iflags);
328 
329 	return;
330 
331 fail:
332 	atmci_disable(host);
333 	host->mrq = NULL;
334 	mrq->cmd->error = -EINVAL;
335 	mmc_request_done(mmc, mrq);
336 }
337 
338 static void atmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
339 {
340 	struct atmel_mci	*host = mmc_priv(mmc);
341 
342 	if (ios->clock) {
343 		u32 clkdiv;
344 
345 		/* Set clock rate */
346 		clkdiv = DIV_ROUND_UP(host->bus_hz, 2 * ios->clock) - 1;
347 		if (clkdiv > 255) {
348 			dev_warn(&mmc->class_dev,
349 				"clock %u too slow; using %lu\n",
350 				ios->clock, host->bus_hz / (2 * 256));
351 			clkdiv = 255;
352 		}
353 
354 		host->mode_reg = MCI_MR_CLKDIV(clkdiv) | MCI_MR_WRPROOF
355 					| MCI_MR_RDPROOF;
356 	}
357 
358 	switch (ios->bus_width) {
359 	case MMC_BUS_WIDTH_1:
360 		host->sdc_reg = 0;
361 		break;
362 	case MMC_BUS_WIDTH_4:
363 		host->sdc_reg = MCI_SDCBUS_4BIT;
364 		break;
365 	}
366 
367 	switch (ios->power_mode) {
368 	case MMC_POWER_ON:
369 		/* Send init sequence (74 clock cycles) */
370 		atmci_enable(host);
371 		mci_writel(host, CMDR, MCI_CMDR_SPCMD_INIT);
372 		while (!(mci_readl(host, SR) & MCI_CMDRDY))
373 			cpu_relax();
374 		atmci_disable(host);
375 		break;
376 	default:
377 		/*
378 		 * TODO: None of the currently available AVR32-based
379 		 * boards allow MMC power to be turned off. Implement
380 		 * power control when this can be tested properly.
381 		 */
382 		break;
383 	}
384 }
385 
386 static int atmci_get_ro(struct mmc_host *mmc)
387 {
388 	int			read_only = 0;
389 	struct atmel_mci	*host = mmc_priv(mmc);
390 
391 	if (host->wp_pin >= 0) {
392 		read_only = gpio_get_value(host->wp_pin);
393 		dev_dbg(&mmc->class_dev, "card is %s\n",
394 				read_only ? "read-only" : "read-write");
395 	} else {
396 		dev_dbg(&mmc->class_dev,
397 			"no pin for checking read-only switch."
398 			" Assuming write-enable.\n");
399 	}
400 
401 	return read_only;
402 }
403 
404 static struct mmc_host_ops atmci_ops = {
405 	.request	= atmci_request,
406 	.set_ios	= atmci_set_ios,
407 	.get_ro		= atmci_get_ro,
408 };
409 
410 static void atmci_command_complete(struct atmel_mci *host,
411 			struct mmc_command *cmd, u32 status)
412 {
413 	/* Read the response from the card (up to 16 bytes) */
414 	cmd->resp[0] = mci_readl(host, RSPR);
415 	cmd->resp[1] = mci_readl(host, RSPR);
416 	cmd->resp[2] = mci_readl(host, RSPR);
417 	cmd->resp[3] = mci_readl(host, RSPR);
418 
419 	if (status & MCI_RTOE)
420 		cmd->error = -ETIMEDOUT;
421 	else if ((cmd->flags & MMC_RSP_CRC) && (status & MCI_RCRCE))
422 		cmd->error = -EILSEQ;
423 	else if (status & (MCI_RINDE | MCI_RDIRE | MCI_RENDE))
424 		cmd->error = -EIO;
425 	else
426 		cmd->error = 0;
427 
428 	if (cmd->error) {
429 		dev_dbg(&host->mmc->class_dev,
430 			"command error: status=0x%08x\n", status);
431 
432 		if (cmd->data) {
433 			host->data = NULL;
434 			mci_writel(host, IDR, MCI_NOTBUSY
435 					| MCI_TXRDY | MCI_RXRDY
436 					| ATMCI_DATA_ERROR_FLAGS);
437 		}
438 	}
439 }
440 
441 static void atmci_detect_change(unsigned long data)
442 {
443 	struct atmel_mci *host = (struct atmel_mci *)data;
444 	struct mmc_request *mrq = host->mrq;
445 	int present;
446 
447 	/*
448 	 * atmci_remove() sets detect_pin to -1 before freeing the
449 	 * interrupt. We must not re-enable the interrupt if it has
450 	 * been freed.
451 	 */
452 	smp_rmb();
453 	if (host->detect_pin < 0)
454 		return;
455 
456 	enable_irq(gpio_to_irq(host->detect_pin));
457 	present = !gpio_get_value(host->detect_pin);
458 
459 	dev_vdbg(&host->pdev->dev, "detect change: %d (was %d)\n",
460 			present, host->present);
461 
462 	if (present != host->present) {
463 		dev_dbg(&host->mmc->class_dev, "card %s\n",
464 			present ? "inserted" : "removed");
465 		host->present = present;
466 
467 		/* Reset controller if card is gone */
468 		if (!present) {
469 			mci_writel(host, CR, MCI_CR_SWRST);
470 			mci_writel(host, IDR, ~0UL);
471 			mci_writel(host, CR, MCI_CR_MCIEN);
472 		}
473 
474 		/* Clean up queue if present */
475 		if (mrq) {
476 			/*
477 			 * Reset controller to terminate any ongoing
478 			 * commands or data transfers.
479 			 */
480 			mci_writel(host, CR, MCI_CR_SWRST);
481 
482 			if (!atmci_is_completed(host, EVENT_CMD_COMPLETE))
483 				mrq->cmd->error = -ENOMEDIUM;
484 
485 			if (mrq->data && !atmci_is_completed(host,
486 						EVENT_DATA_COMPLETE)) {
487 				host->data = NULL;
488 				mrq->data->error = -ENOMEDIUM;
489 			}
490 			if (mrq->stop && !atmci_is_completed(host,
491 						EVENT_STOP_COMPLETE))
492 				mrq->stop->error = -ENOMEDIUM;
493 
494 			host->cmd = NULL;
495 			atmci_request_end(host->mmc, mrq);
496 		}
497 
498 		mmc_detect_change(host->mmc, 0);
499 	}
500 }
501 
502 static void atmci_tasklet_func(unsigned long priv)
503 {
504 	struct mmc_host		*mmc = (struct mmc_host *)priv;
505 	struct atmel_mci	*host = mmc_priv(mmc);
506 	struct mmc_request	*mrq = host->mrq;
507 	struct mmc_data		*data = host->data;
508 
509 	dev_vdbg(&mmc->class_dev,
510 		"tasklet: pending/completed/mask %lx/%lx/%x\n",
511 		host->pending_events, host->completed_events,
512 		mci_readl(host, IMR));
513 
514 	if (atmci_test_and_clear_pending(host, EVENT_CMD_COMPLETE)) {
515 		/*
516 		 * host->cmd must be set to NULL before the interrupt
517 		 * handler sees EVENT_CMD_COMPLETE
518 		 */
519 		host->cmd = NULL;
520 		smp_wmb();
521 		atmci_set_completed(host, EVENT_CMD_COMPLETE);
522 		atmci_command_complete(host, mrq->cmd, host->cmd_status);
523 
524 		if (!mrq->cmd->error && mrq->stop
525 				&& atmci_is_completed(host, EVENT_XFER_COMPLETE)
526 				&& !atmci_test_and_set_completed(host,
527 					EVENT_STOP_SENT))
528 			send_stop_cmd(host->mmc, mrq->data);
529 	}
530 	if (atmci_test_and_clear_pending(host, EVENT_STOP_COMPLETE)) {
531 		/*
532 		 * host->cmd must be set to NULL before the interrupt
533 		 * handler sees EVENT_STOP_COMPLETE
534 		 */
535 		host->cmd = NULL;
536 		smp_wmb();
537 		atmci_set_completed(host, EVENT_STOP_COMPLETE);
538 		atmci_command_complete(host, mrq->stop, host->stop_status);
539 	}
540 	if (atmci_test_and_clear_pending(host, EVENT_DATA_ERROR)) {
541 		u32 status = host->data_status;
542 
543 		dev_vdbg(&mmc->class_dev, "data error: status=%08x\n", status);
544 
545 		atmci_set_completed(host, EVENT_DATA_ERROR);
546 		atmci_set_completed(host, EVENT_DATA_COMPLETE);
547 
548 		if (status & MCI_DTOE) {
549 			dev_dbg(&mmc->class_dev,
550 					"data timeout error\n");
551 			data->error = -ETIMEDOUT;
552 		} else if (status & MCI_DCRCE) {
553 			dev_dbg(&mmc->class_dev, "data CRC error\n");
554 			data->error = -EILSEQ;
555 		} else {
556 			dev_dbg(&mmc->class_dev,
557 					"data FIFO error (status=%08x)\n",
558 					status);
559 			data->error = -EIO;
560 		}
561 
562 		if (host->present && data->stop
563 				&& atmci_is_completed(host, EVENT_CMD_COMPLETE)
564 				&& !atmci_test_and_set_completed(
565 					host, EVENT_STOP_SENT))
566 			send_stop_cmd(host->mmc, data);
567 
568 		host->data = NULL;
569 	}
570 	if (atmci_test_and_clear_pending(host, EVENT_DATA_COMPLETE)) {
571 		atmci_set_completed(host, EVENT_DATA_COMPLETE);
572 
573 		if (!atmci_is_completed(host, EVENT_DATA_ERROR)) {
574 			data->bytes_xfered = data->blocks * data->blksz;
575 			data->error = 0;
576 		}
577 
578 		host->data = NULL;
579 	}
580 
581 	if (host->mrq && !host->cmd && !host->data)
582 		atmci_request_end(mmc, host->mrq);
583 }
584 
585 static void atmci_read_data_pio(struct atmel_mci *host)
586 {
587 	struct scatterlist	*sg = host->sg;
588 	void			*buf = sg_virt(sg);
589 	unsigned int		offset = host->pio_offset;
590 	struct mmc_data		*data = host->data;
591 	u32			value;
592 	u32			status;
593 	unsigned int		nbytes = 0;
594 
595 	do {
596 		value = mci_readl(host, RDR);
597 		if (likely(offset + 4 <= sg->length)) {
598 			put_unaligned(value, (u32 *)(buf + offset));
599 
600 			offset += 4;
601 			nbytes += 4;
602 
603 			if (offset == sg->length) {
604 				host->sg = sg = sg_next(sg);
605 				if (!sg)
606 					goto done;
607 
608 				offset = 0;
609 				buf = sg_virt(sg);
610 			}
611 		} else {
612 			unsigned int remaining = sg->length - offset;
613 			memcpy(buf + offset, &value, remaining);
614 			nbytes += remaining;
615 
616 			flush_dcache_page(sg_page(sg));
617 			host->sg = sg = sg_next(sg);
618 			if (!sg)
619 				goto done;
620 
621 			offset = 4 - remaining;
622 			buf = sg_virt(sg);
623 			memcpy(buf, (u8 *)&value + remaining, offset);
624 			nbytes += offset;
625 		}
626 
627 		status = mci_readl(host, SR);
628 		if (status & ATMCI_DATA_ERROR_FLAGS) {
629 			mci_writel(host, IDR, (MCI_NOTBUSY | MCI_RXRDY
630 						| ATMCI_DATA_ERROR_FLAGS));
631 			host->data_status = status;
632 			atmci_set_pending(host, EVENT_DATA_ERROR);
633 			tasklet_schedule(&host->tasklet);
634 			break;
635 		}
636 	} while (status & MCI_RXRDY);
637 
638 	host->pio_offset = offset;
639 	data->bytes_xfered += nbytes;
640 
641 	return;
642 
643 done:
644 	mci_writel(host, IDR, MCI_RXRDY);
645 	mci_writel(host, IER, MCI_NOTBUSY);
646 	data->bytes_xfered += nbytes;
647 	atmci_set_completed(host, EVENT_XFER_COMPLETE);
648 	if (data->stop && atmci_is_completed(host, EVENT_CMD_COMPLETE)
649 			&& !atmci_test_and_set_completed(host, EVENT_STOP_SENT))
650 		send_stop_cmd(host->mmc, data);
651 }
652 
653 static void atmci_write_data_pio(struct atmel_mci *host)
654 {
655 	struct scatterlist	*sg = host->sg;
656 	void			*buf = sg_virt(sg);
657 	unsigned int		offset = host->pio_offset;
658 	struct mmc_data		*data = host->data;
659 	u32			value;
660 	u32			status;
661 	unsigned int		nbytes = 0;
662 
663 	do {
664 		if (likely(offset + 4 <= sg->length)) {
665 			value = get_unaligned((u32 *)(buf + offset));
666 			mci_writel(host, TDR, value);
667 
668 			offset += 4;
669 			nbytes += 4;
670 			if (offset == sg->length) {
671 				host->sg = sg = sg_next(sg);
672 				if (!sg)
673 					goto done;
674 
675 				offset = 0;
676 				buf = sg_virt(sg);
677 			}
678 		} else {
679 			unsigned int remaining = sg->length - offset;
680 
681 			value = 0;
682 			memcpy(&value, buf + offset, remaining);
683 			nbytes += remaining;
684 
685 			host->sg = sg = sg_next(sg);
686 			if (!sg) {
687 				mci_writel(host, TDR, value);
688 				goto done;
689 			}
690 
691 			offset = 4 - remaining;
692 			buf = sg_virt(sg);
693 			memcpy((u8 *)&value + remaining, buf, offset);
694 			mci_writel(host, TDR, value);
695 			nbytes += offset;
696 		}
697 
698 		status = mci_readl(host, SR);
699 		if (status & ATMCI_DATA_ERROR_FLAGS) {
700 			mci_writel(host, IDR, (MCI_NOTBUSY | MCI_TXRDY
701 						| ATMCI_DATA_ERROR_FLAGS));
702 			host->data_status = status;
703 			atmci_set_pending(host, EVENT_DATA_ERROR);
704 			tasklet_schedule(&host->tasklet);
705 			break;
706 		}
707 	} while (status & MCI_TXRDY);
708 
709 	host->pio_offset = offset;
710 	data->bytes_xfered += nbytes;
711 
712 	return;
713 
714 done:
715 	mci_writel(host, IDR, MCI_TXRDY);
716 	mci_writel(host, IER, MCI_NOTBUSY);
717 	data->bytes_xfered += nbytes;
718 	atmci_set_completed(host, EVENT_XFER_COMPLETE);
719 	if (data->stop && atmci_is_completed(host, EVENT_CMD_COMPLETE)
720 			&& !atmci_test_and_set_completed(host, EVENT_STOP_SENT))
721 		send_stop_cmd(host->mmc, data);
722 }
723 
724 static void atmci_cmd_interrupt(struct mmc_host *mmc, u32 status)
725 {
726 	struct atmel_mci	*host = mmc_priv(mmc);
727 
728 	mci_writel(host, IDR, MCI_CMDRDY);
729 
730 	if (atmci_is_completed(host, EVENT_STOP_SENT)) {
731 		host->stop_status = status;
732 		atmci_set_pending(host, EVENT_STOP_COMPLETE);
733 	} else {
734 		host->cmd_status = status;
735 		atmci_set_pending(host, EVENT_CMD_COMPLETE);
736 	}
737 
738 	tasklet_schedule(&host->tasklet);
739 }
740 
741 static irqreturn_t atmci_interrupt(int irq, void *dev_id)
742 {
743 	struct mmc_host		*mmc = dev_id;
744 	struct atmel_mci	*host = mmc_priv(mmc);
745 	u32			status, mask, pending;
746 	unsigned int		pass_count = 0;
747 
748 	spin_lock(&mmc->lock);
749 
750 	do {
751 		status = mci_readl(host, SR);
752 		mask = mci_readl(host, IMR);
753 		pending = status & mask;
754 		if (!pending)
755 			break;
756 
757 		if (pending & ATMCI_DATA_ERROR_FLAGS) {
758 			mci_writel(host, IDR, ATMCI_DATA_ERROR_FLAGS
759 					| MCI_RXRDY | MCI_TXRDY);
760 			pending &= mci_readl(host, IMR);
761 			host->data_status = status;
762 			atmci_set_pending(host, EVENT_DATA_ERROR);
763 			tasklet_schedule(&host->tasklet);
764 		}
765 		if (pending & MCI_NOTBUSY) {
766 			mci_writel(host, IDR, (MCI_NOTBUSY
767 					       | ATMCI_DATA_ERROR_FLAGS));
768 			atmci_set_pending(host, EVENT_DATA_COMPLETE);
769 			tasklet_schedule(&host->tasklet);
770 		}
771 		if (pending & MCI_RXRDY)
772 			atmci_read_data_pio(host);
773 		if (pending & MCI_TXRDY)
774 			atmci_write_data_pio(host);
775 
776 		if (pending & MCI_CMDRDY)
777 			atmci_cmd_interrupt(mmc, status);
778 	} while (pass_count++ < 5);
779 
780 	spin_unlock(&mmc->lock);
781 
782 	return pass_count ? IRQ_HANDLED : IRQ_NONE;
783 }
784 
785 static irqreturn_t atmci_detect_interrupt(int irq, void *dev_id)
786 {
787 	struct mmc_host		*mmc = dev_id;
788 	struct atmel_mci	*host = mmc_priv(mmc);
789 
790 	/*
791 	 * Disable interrupts until the pin has stabilized and check
792 	 * the state then. Use mod_timer() since we may be in the
793 	 * middle of the timer routine when this interrupt triggers.
794 	 */
795 	disable_irq_nosync(irq);
796 	mod_timer(&host->detect_timer, jiffies + msecs_to_jiffies(20));
797 
798 	return IRQ_HANDLED;
799 }
800 
801 static int __init atmci_probe(struct platform_device *pdev)
802 {
803 	struct mci_platform_data	*pdata;
804 	struct atmel_mci *host;
805 	struct mmc_host *mmc;
806 	struct resource *regs;
807 	int irq;
808 	int ret;
809 
810 	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
811 	if (!regs)
812 		return -ENXIO;
813 	pdata = pdev->dev.platform_data;
814 	if (!pdata)
815 		return -ENXIO;
816 	irq = platform_get_irq(pdev, 0);
817 	if (irq < 0)
818 		return irq;
819 
820 	mmc = mmc_alloc_host(sizeof(struct atmel_mci), &pdev->dev);
821 	if (!mmc)
822 		return -ENOMEM;
823 
824 	host = mmc_priv(mmc);
825 	host->pdev = pdev;
826 	host->mmc = mmc;
827 	host->detect_pin = pdata->detect_pin;
828 	host->wp_pin = pdata->wp_pin;
829 
830 	host->mck = clk_get(&pdev->dev, "mci_clk");
831 	if (IS_ERR(host->mck)) {
832 		ret = PTR_ERR(host->mck);
833 		goto err_clk_get;
834 	}
835 
836 	ret = -ENOMEM;
837 	host->regs = ioremap(regs->start, regs->end - regs->start + 1);
838 	if (!host->regs)
839 		goto err_ioremap;
840 
841 	clk_enable(host->mck);
842 	mci_writel(host, CR, MCI_CR_SWRST);
843 	host->bus_hz = clk_get_rate(host->mck);
844 	clk_disable(host->mck);
845 
846 	host->mapbase = regs->start;
847 
848 	mmc->ops = &atmci_ops;
849 	mmc->f_min = (host->bus_hz + 511) / 512;
850 	mmc->f_max = host->bus_hz / 2;
851 	mmc->ocr_avail	= MMC_VDD_32_33 | MMC_VDD_33_34;
852 	mmc->caps |= MMC_CAP_4_BIT_DATA;
853 
854 	mmc->max_hw_segs = 64;
855 	mmc->max_phys_segs = 64;
856 	mmc->max_req_size = 32768 * 512;
857 	mmc->max_blk_size = 32768;
858 	mmc->max_blk_count = 512;
859 
860 	tasklet_init(&host->tasklet, atmci_tasklet_func, (unsigned long)mmc);
861 
862 	ret = request_irq(irq, atmci_interrupt, 0, pdev->dev.bus_id, mmc);
863 	if (ret)
864 		goto err_request_irq;
865 
866 	/* Assume card is present if we don't have a detect pin */
867 	host->present = 1;
868 	if (host->detect_pin >= 0) {
869 		if (gpio_request(host->detect_pin, "mmc_detect")) {
870 			dev_dbg(&mmc->class_dev, "no detect pin available\n");
871 			host->detect_pin = -1;
872 		} else {
873 			host->present = !gpio_get_value(host->detect_pin);
874 		}
875 	}
876 	if (host->wp_pin >= 0) {
877 		if (gpio_request(host->wp_pin, "mmc_wp")) {
878 			dev_dbg(&mmc->class_dev, "no WP pin available\n");
879 			host->wp_pin = -1;
880 		}
881 	}
882 
883 	platform_set_drvdata(pdev, host);
884 
885 	mmc_add_host(mmc);
886 
887 	if (host->detect_pin >= 0) {
888 		setup_timer(&host->detect_timer, atmci_detect_change,
889 				(unsigned long)host);
890 
891 		ret = request_irq(gpio_to_irq(host->detect_pin),
892 				atmci_detect_interrupt,
893 				IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,
894 				"mmc-detect", mmc);
895 		if (ret) {
896 			dev_dbg(&mmc->class_dev,
897 				"could not request IRQ %d for detect pin\n",
898 				gpio_to_irq(host->detect_pin));
899 			gpio_free(host->detect_pin);
900 			host->detect_pin = -1;
901 		}
902 	}
903 
904 	dev_info(&mmc->class_dev,
905 			"Atmel MCI controller at 0x%08lx irq %d\n",
906 			host->mapbase, irq);
907 
908 	return 0;
909 
910 err_request_irq:
911 	iounmap(host->regs);
912 err_ioremap:
913 	clk_put(host->mck);
914 err_clk_get:
915 	mmc_free_host(mmc);
916 	return ret;
917 }
918 
919 static int __exit atmci_remove(struct platform_device *pdev)
920 {
921 	struct atmel_mci *host = platform_get_drvdata(pdev);
922 
923 	platform_set_drvdata(pdev, NULL);
924 
925 	if (host) {
926 		if (host->detect_pin >= 0) {
927 			int pin = host->detect_pin;
928 
929 			/* Make sure the timer doesn't enable the interrupt */
930 			host->detect_pin = -1;
931 			smp_wmb();
932 
933 			free_irq(gpio_to_irq(pin), host->mmc);
934 			del_timer_sync(&host->detect_timer);
935 			gpio_free(pin);
936 		}
937 
938 		mmc_remove_host(host->mmc);
939 
940 		clk_enable(host->mck);
941 		mci_writel(host, IDR, ~0UL);
942 		mci_writel(host, CR, MCI_CR_MCIDIS);
943 		mci_readl(host, SR);
944 		clk_disable(host->mck);
945 
946 		if (host->wp_pin >= 0)
947 			gpio_free(host->wp_pin);
948 
949 		free_irq(platform_get_irq(pdev, 0), host->mmc);
950 		iounmap(host->regs);
951 
952 		clk_put(host->mck);
953 
954 		mmc_free_host(host->mmc);
955 	}
956 	return 0;
957 }
958 
959 static struct platform_driver atmci_driver = {
960 	.remove		= __exit_p(atmci_remove),
961 	.driver		= {
962 		.name		= "atmel_mci",
963 	},
964 };
965 
966 static int __init atmci_init(void)
967 {
968 	return platform_driver_probe(&atmci_driver, atmci_probe);
969 }
970 
971 static void __exit atmci_exit(void)
972 {
973 	platform_driver_unregister(&atmci_driver);
974 }
975 
976 module_init(atmci_init);
977 module_exit(atmci_exit);
978 
979 MODULE_DESCRIPTION("Atmel Multimedia Card Interface driver");
980 MODULE_AUTHOR("Haavard Skinnemoen <haavard.skinnemoen@atmel.com>");
981 MODULE_LICENSE("GPL v2");
982