xref: /openbmc/linux/drivers/mmc/host/atmel-mci.c (revision 8fa5723aa7e053d498336b48448b292fc2e0458b)
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/debugfs.h>
13 #include <linux/device.h>
14 #include <linux/dmaengine.h>
15 #include <linux/dma-mapping.h>
16 #include <linux/err.h>
17 #include <linux/gpio.h>
18 #include <linux/init.h>
19 #include <linux/interrupt.h>
20 #include <linux/ioport.h>
21 #include <linux/module.h>
22 #include <linux/platform_device.h>
23 #include <linux/scatterlist.h>
24 #include <linux/seq_file.h>
25 #include <linux/stat.h>
26 
27 #include <linux/mmc/host.h>
28 
29 #include <asm/atmel-mci.h>
30 #include <asm/io.h>
31 #include <asm/unaligned.h>
32 
33 #include <mach/board.h>
34 
35 #include "atmel-mci-regs.h"
36 
37 #define ATMCI_DATA_ERROR_FLAGS	(MCI_DCRCE | MCI_DTOE | MCI_OVRE | MCI_UNRE)
38 #define ATMCI_DMA_THRESHOLD	16
39 
40 enum {
41 	EVENT_CMD_COMPLETE = 0,
42 	EVENT_XFER_COMPLETE,
43 	EVENT_DATA_COMPLETE,
44 	EVENT_DATA_ERROR,
45 };
46 
47 enum atmel_mci_state {
48 	STATE_IDLE = 0,
49 	STATE_SENDING_CMD,
50 	STATE_SENDING_DATA,
51 	STATE_DATA_BUSY,
52 	STATE_SENDING_STOP,
53 	STATE_DATA_ERROR,
54 };
55 
56 struct atmel_mci_dma {
57 #ifdef CONFIG_MMC_ATMELMCI_DMA
58 	struct dma_client		client;
59 	struct dma_chan			*chan;
60 	struct dma_async_tx_descriptor	*data_desc;
61 #endif
62 };
63 
64 /**
65  * struct atmel_mci - MMC controller state shared between all slots
66  * @lock: Spinlock protecting the queue and associated data.
67  * @regs: Pointer to MMIO registers.
68  * @sg: Scatterlist entry currently being processed by PIO code, if any.
69  * @pio_offset: Offset into the current scatterlist entry.
70  * @cur_slot: The slot which is currently using the controller.
71  * @mrq: The request currently being processed on @cur_slot,
72  *	or NULL if the controller is idle.
73  * @cmd: The command currently being sent to the card, or NULL.
74  * @data: The data currently being transferred, or NULL if no data
75  *	transfer is in progress.
76  * @dma: DMA client state.
77  * @data_chan: DMA channel being used for the current data transfer.
78  * @cmd_status: Snapshot of SR taken upon completion of the current
79  *	command. Only valid when EVENT_CMD_COMPLETE is pending.
80  * @data_status: Snapshot of SR taken upon completion of the current
81  *	data transfer. Only valid when EVENT_DATA_COMPLETE or
82  *	EVENT_DATA_ERROR is pending.
83  * @stop_cmdr: Value to be loaded into CMDR when the stop command is
84  *	to be sent.
85  * @tasklet: Tasklet running the request state machine.
86  * @pending_events: Bitmask of events flagged by the interrupt handler
87  *	to be processed by the tasklet.
88  * @completed_events: Bitmask of events which the state machine has
89  *	processed.
90  * @state: Tasklet state.
91  * @queue: List of slots waiting for access to the controller.
92  * @need_clock_update: Update the clock rate before the next request.
93  * @need_reset: Reset controller before next request.
94  * @mode_reg: Value of the MR register.
95  * @bus_hz: The rate of @mck in Hz. This forms the basis for MMC bus
96  *	rate and timeout calculations.
97  * @mapbase: Physical address of the MMIO registers.
98  * @mck: The peripheral bus clock hooked up to the MMC controller.
99  * @pdev: Platform device associated with the MMC controller.
100  * @slot: Slots sharing this MMC controller.
101  *
102  * Locking
103  * =======
104  *
105  * @lock is a softirq-safe spinlock protecting @queue as well as
106  * @cur_slot, @mrq and @state. These must always be updated
107  * at the same time while holding @lock.
108  *
109  * @lock also protects mode_reg and need_clock_update since these are
110  * used to synchronize mode register updates with the queue
111  * processing.
112  *
113  * The @mrq field of struct atmel_mci_slot is also protected by @lock,
114  * and must always be written at the same time as the slot is added to
115  * @queue.
116  *
117  * @pending_events and @completed_events are accessed using atomic bit
118  * operations, so they don't need any locking.
119  *
120  * None of the fields touched by the interrupt handler need any
121  * locking. However, ordering is important: Before EVENT_DATA_ERROR or
122  * EVENT_DATA_COMPLETE is set in @pending_events, all data-related
123  * interrupts must be disabled and @data_status updated with a
124  * snapshot of SR. Similarly, before EVENT_CMD_COMPLETE is set, the
125  * CMDRDY interupt must be disabled and @cmd_status updated with a
126  * snapshot of SR, and before EVENT_XFER_COMPLETE can be set, the
127  * bytes_xfered field of @data must be written. This is ensured by
128  * using barriers.
129  */
130 struct atmel_mci {
131 	spinlock_t		lock;
132 	void __iomem		*regs;
133 
134 	struct scatterlist	*sg;
135 	unsigned int		pio_offset;
136 
137 	struct atmel_mci_slot	*cur_slot;
138 	struct mmc_request	*mrq;
139 	struct mmc_command	*cmd;
140 	struct mmc_data		*data;
141 
142 	struct atmel_mci_dma	dma;
143 	struct dma_chan		*data_chan;
144 
145 	u32			cmd_status;
146 	u32			data_status;
147 	u32			stop_cmdr;
148 
149 	struct tasklet_struct	tasklet;
150 	unsigned long		pending_events;
151 	unsigned long		completed_events;
152 	enum atmel_mci_state	state;
153 	struct list_head	queue;
154 
155 	bool			need_clock_update;
156 	bool			need_reset;
157 	u32			mode_reg;
158 	unsigned long		bus_hz;
159 	unsigned long		mapbase;
160 	struct clk		*mck;
161 	struct platform_device	*pdev;
162 
163 	struct atmel_mci_slot	*slot[ATMEL_MCI_MAX_NR_SLOTS];
164 };
165 
166 /**
167  * struct atmel_mci_slot - MMC slot state
168  * @mmc: The mmc_host representing this slot.
169  * @host: The MMC controller this slot is using.
170  * @sdc_reg: Value of SDCR to be written before using this slot.
171  * @mrq: mmc_request currently being processed or waiting to be
172  *	processed, or NULL when the slot is idle.
173  * @queue_node: List node for placing this node in the @queue list of
174  *	&struct atmel_mci.
175  * @clock: Clock rate configured by set_ios(). Protected by host->lock.
176  * @flags: Random state bits associated with the slot.
177  * @detect_pin: GPIO pin used for card detection, or negative if not
178  *	available.
179  * @wp_pin: GPIO pin used for card write protect sending, or negative
180  *	if not available.
181  * @detect_timer: Timer used for debouncing @detect_pin interrupts.
182  */
183 struct atmel_mci_slot {
184 	struct mmc_host		*mmc;
185 	struct atmel_mci	*host;
186 
187 	u32			sdc_reg;
188 
189 	struct mmc_request	*mrq;
190 	struct list_head	queue_node;
191 
192 	unsigned int		clock;
193 	unsigned long		flags;
194 #define ATMCI_CARD_PRESENT	0
195 #define ATMCI_CARD_NEED_INIT	1
196 #define ATMCI_SHUTDOWN		2
197 
198 	int			detect_pin;
199 	int			wp_pin;
200 
201 	struct timer_list	detect_timer;
202 };
203 
204 #define atmci_test_and_clear_pending(host, event)		\
205 	test_and_clear_bit(event, &host->pending_events)
206 #define atmci_set_completed(host, event)			\
207 	set_bit(event, &host->completed_events)
208 #define atmci_set_pending(host, event)				\
209 	set_bit(event, &host->pending_events)
210 
211 /*
212  * The debugfs stuff below is mostly optimized away when
213  * CONFIG_DEBUG_FS is not set.
214  */
215 static int atmci_req_show(struct seq_file *s, void *v)
216 {
217 	struct atmel_mci_slot	*slot = s->private;
218 	struct mmc_request	*mrq;
219 	struct mmc_command	*cmd;
220 	struct mmc_command	*stop;
221 	struct mmc_data		*data;
222 
223 	/* Make sure we get a consistent snapshot */
224 	spin_lock_bh(&slot->host->lock);
225 	mrq = slot->mrq;
226 
227 	if (mrq) {
228 		cmd = mrq->cmd;
229 		data = mrq->data;
230 		stop = mrq->stop;
231 
232 		if (cmd)
233 			seq_printf(s,
234 				"CMD%u(0x%x) flg %x rsp %x %x %x %x err %d\n",
235 				cmd->opcode, cmd->arg, cmd->flags,
236 				cmd->resp[0], cmd->resp[1], cmd->resp[2],
237 				cmd->resp[2], cmd->error);
238 		if (data)
239 			seq_printf(s, "DATA %u / %u * %u flg %x err %d\n",
240 				data->bytes_xfered, data->blocks,
241 				data->blksz, data->flags, data->error);
242 		if (stop)
243 			seq_printf(s,
244 				"CMD%u(0x%x) flg %x rsp %x %x %x %x err %d\n",
245 				stop->opcode, stop->arg, stop->flags,
246 				stop->resp[0], stop->resp[1], stop->resp[2],
247 				stop->resp[2], stop->error);
248 	}
249 
250 	spin_unlock_bh(&slot->host->lock);
251 
252 	return 0;
253 }
254 
255 static int atmci_req_open(struct inode *inode, struct file *file)
256 {
257 	return single_open(file, atmci_req_show, inode->i_private);
258 }
259 
260 static const struct file_operations atmci_req_fops = {
261 	.owner		= THIS_MODULE,
262 	.open		= atmci_req_open,
263 	.read		= seq_read,
264 	.llseek		= seq_lseek,
265 	.release	= single_release,
266 };
267 
268 static void atmci_show_status_reg(struct seq_file *s,
269 		const char *regname, u32 value)
270 {
271 	static const char	*sr_bit[] = {
272 		[0]	= "CMDRDY",
273 		[1]	= "RXRDY",
274 		[2]	= "TXRDY",
275 		[3]	= "BLKE",
276 		[4]	= "DTIP",
277 		[5]	= "NOTBUSY",
278 		[8]	= "SDIOIRQA",
279 		[9]	= "SDIOIRQB",
280 		[16]	= "RINDE",
281 		[17]	= "RDIRE",
282 		[18]	= "RCRCE",
283 		[19]	= "RENDE",
284 		[20]	= "RTOE",
285 		[21]	= "DCRCE",
286 		[22]	= "DTOE",
287 		[30]	= "OVRE",
288 		[31]	= "UNRE",
289 	};
290 	unsigned int		i;
291 
292 	seq_printf(s, "%s:\t0x%08x", regname, value);
293 	for (i = 0; i < ARRAY_SIZE(sr_bit); i++) {
294 		if (value & (1 << i)) {
295 			if (sr_bit[i])
296 				seq_printf(s, " %s", sr_bit[i]);
297 			else
298 				seq_puts(s, " UNKNOWN");
299 		}
300 	}
301 	seq_putc(s, '\n');
302 }
303 
304 static int atmci_regs_show(struct seq_file *s, void *v)
305 {
306 	struct atmel_mci	*host = s->private;
307 	u32			*buf;
308 
309 	buf = kmalloc(MCI_REGS_SIZE, GFP_KERNEL);
310 	if (!buf)
311 		return -ENOMEM;
312 
313 	/*
314 	 * Grab a more or less consistent snapshot. Note that we're
315 	 * not disabling interrupts, so IMR and SR may not be
316 	 * consistent.
317 	 */
318 	spin_lock_bh(&host->lock);
319 	clk_enable(host->mck);
320 	memcpy_fromio(buf, host->regs, MCI_REGS_SIZE);
321 	clk_disable(host->mck);
322 	spin_unlock_bh(&host->lock);
323 
324 	seq_printf(s, "MR:\t0x%08x%s%s CLKDIV=%u\n",
325 			buf[MCI_MR / 4],
326 			buf[MCI_MR / 4] & MCI_MR_RDPROOF ? " RDPROOF" : "",
327 			buf[MCI_MR / 4] & MCI_MR_WRPROOF ? " WRPROOF" : "",
328 			buf[MCI_MR / 4] & 0xff);
329 	seq_printf(s, "DTOR:\t0x%08x\n", buf[MCI_DTOR / 4]);
330 	seq_printf(s, "SDCR:\t0x%08x\n", buf[MCI_SDCR / 4]);
331 	seq_printf(s, "ARGR:\t0x%08x\n", buf[MCI_ARGR / 4]);
332 	seq_printf(s, "BLKR:\t0x%08x BCNT=%u BLKLEN=%u\n",
333 			buf[MCI_BLKR / 4],
334 			buf[MCI_BLKR / 4] & 0xffff,
335 			(buf[MCI_BLKR / 4] >> 16) & 0xffff);
336 
337 	/* Don't read RSPR and RDR; it will consume the data there */
338 
339 	atmci_show_status_reg(s, "SR", buf[MCI_SR / 4]);
340 	atmci_show_status_reg(s, "IMR", buf[MCI_IMR / 4]);
341 
342 	kfree(buf);
343 
344 	return 0;
345 }
346 
347 static int atmci_regs_open(struct inode *inode, struct file *file)
348 {
349 	return single_open(file, atmci_regs_show, inode->i_private);
350 }
351 
352 static const struct file_operations atmci_regs_fops = {
353 	.owner		= THIS_MODULE,
354 	.open		= atmci_regs_open,
355 	.read		= seq_read,
356 	.llseek		= seq_lseek,
357 	.release	= single_release,
358 };
359 
360 static void atmci_init_debugfs(struct atmel_mci_slot *slot)
361 {
362 	struct mmc_host		*mmc = slot->mmc;
363 	struct atmel_mci	*host = slot->host;
364 	struct dentry		*root;
365 	struct dentry		*node;
366 
367 	root = mmc->debugfs_root;
368 	if (!root)
369 		return;
370 
371 	node = debugfs_create_file("regs", S_IRUSR, root, host,
372 			&atmci_regs_fops);
373 	if (IS_ERR(node))
374 		return;
375 	if (!node)
376 		goto err;
377 
378 	node = debugfs_create_file("req", S_IRUSR, root, slot, &atmci_req_fops);
379 	if (!node)
380 		goto err;
381 
382 	node = debugfs_create_u32("state", S_IRUSR, root, (u32 *)&host->state);
383 	if (!node)
384 		goto err;
385 
386 	node = debugfs_create_x32("pending_events", S_IRUSR, root,
387 				     (u32 *)&host->pending_events);
388 	if (!node)
389 		goto err;
390 
391 	node = debugfs_create_x32("completed_events", S_IRUSR, root,
392 				     (u32 *)&host->completed_events);
393 	if (!node)
394 		goto err;
395 
396 	return;
397 
398 err:
399 	dev_err(&mmc->class_dev, "failed to initialize debugfs for slot\n");
400 }
401 
402 static inline unsigned int ns_to_clocks(struct atmel_mci *host,
403 					unsigned int ns)
404 {
405 	return (ns * (host->bus_hz / 1000000) + 999) / 1000;
406 }
407 
408 static void atmci_set_timeout(struct atmel_mci *host,
409 		struct atmel_mci_slot *slot, struct mmc_data *data)
410 {
411 	static unsigned	dtomul_to_shift[] = {
412 		0, 4, 7, 8, 10, 12, 16, 20
413 	};
414 	unsigned	timeout;
415 	unsigned	dtocyc;
416 	unsigned	dtomul;
417 
418 	timeout = ns_to_clocks(host, data->timeout_ns) + data->timeout_clks;
419 
420 	for (dtomul = 0; dtomul < 8; dtomul++) {
421 		unsigned shift = dtomul_to_shift[dtomul];
422 		dtocyc = (timeout + (1 << shift) - 1) >> shift;
423 		if (dtocyc < 15)
424 			break;
425 	}
426 
427 	if (dtomul >= 8) {
428 		dtomul = 7;
429 		dtocyc = 15;
430 	}
431 
432 	dev_vdbg(&slot->mmc->class_dev, "setting timeout to %u cycles\n",
433 			dtocyc << dtomul_to_shift[dtomul]);
434 	mci_writel(host, DTOR, (MCI_DTOMUL(dtomul) | MCI_DTOCYC(dtocyc)));
435 }
436 
437 /*
438  * Return mask with command flags to be enabled for this command.
439  */
440 static u32 atmci_prepare_command(struct mmc_host *mmc,
441 				 struct mmc_command *cmd)
442 {
443 	struct mmc_data	*data;
444 	u32		cmdr;
445 
446 	cmd->error = -EINPROGRESS;
447 
448 	cmdr = MCI_CMDR_CMDNB(cmd->opcode);
449 
450 	if (cmd->flags & MMC_RSP_PRESENT) {
451 		if (cmd->flags & MMC_RSP_136)
452 			cmdr |= MCI_CMDR_RSPTYP_136BIT;
453 		else
454 			cmdr |= MCI_CMDR_RSPTYP_48BIT;
455 	}
456 
457 	/*
458 	 * This should really be MAXLAT_5 for CMD2 and ACMD41, but
459 	 * it's too difficult to determine whether this is an ACMD or
460 	 * not. Better make it 64.
461 	 */
462 	cmdr |= MCI_CMDR_MAXLAT_64CYC;
463 
464 	if (mmc->ios.bus_mode == MMC_BUSMODE_OPENDRAIN)
465 		cmdr |= MCI_CMDR_OPDCMD;
466 
467 	data = cmd->data;
468 	if (data) {
469 		cmdr |= MCI_CMDR_START_XFER;
470 		if (data->flags & MMC_DATA_STREAM)
471 			cmdr |= MCI_CMDR_STREAM;
472 		else if (data->blocks > 1)
473 			cmdr |= MCI_CMDR_MULTI_BLOCK;
474 		else
475 			cmdr |= MCI_CMDR_BLOCK;
476 
477 		if (data->flags & MMC_DATA_READ)
478 			cmdr |= MCI_CMDR_TRDIR_READ;
479 	}
480 
481 	return cmdr;
482 }
483 
484 static void atmci_start_command(struct atmel_mci *host,
485 		struct mmc_command *cmd, u32 cmd_flags)
486 {
487 	WARN_ON(host->cmd);
488 	host->cmd = cmd;
489 
490 	dev_vdbg(&host->pdev->dev,
491 			"start command: ARGR=0x%08x CMDR=0x%08x\n",
492 			cmd->arg, cmd_flags);
493 
494 	mci_writel(host, ARGR, cmd->arg);
495 	mci_writel(host, CMDR, cmd_flags);
496 }
497 
498 static void send_stop_cmd(struct atmel_mci *host, struct mmc_data *data)
499 {
500 	atmci_start_command(host, data->stop, host->stop_cmdr);
501 	mci_writel(host, IER, MCI_CMDRDY);
502 }
503 
504 #ifdef CONFIG_MMC_ATMELMCI_DMA
505 static void atmci_dma_cleanup(struct atmel_mci *host)
506 {
507 	struct mmc_data			*data = host->data;
508 
509 	dma_unmap_sg(&host->pdev->dev, data->sg, data->sg_len,
510 		     ((data->flags & MMC_DATA_WRITE)
511 		      ? DMA_TO_DEVICE : DMA_FROM_DEVICE));
512 }
513 
514 static void atmci_stop_dma(struct atmel_mci *host)
515 {
516 	struct dma_chan *chan = host->data_chan;
517 
518 	if (chan) {
519 		chan->device->device_terminate_all(chan);
520 		atmci_dma_cleanup(host);
521 	} else {
522 		/* Data transfer was stopped by the interrupt handler */
523 		atmci_set_pending(host, EVENT_XFER_COMPLETE);
524 		mci_writel(host, IER, MCI_NOTBUSY);
525 	}
526 }
527 
528 /* This function is called by the DMA driver from tasklet context. */
529 static void atmci_dma_complete(void *arg)
530 {
531 	struct atmel_mci	*host = arg;
532 	struct mmc_data		*data = host->data;
533 
534 	dev_vdbg(&host->pdev->dev, "DMA complete\n");
535 
536 	atmci_dma_cleanup(host);
537 
538 	/*
539 	 * If the card was removed, data will be NULL. No point trying
540 	 * to send the stop command or waiting for NBUSY in this case.
541 	 */
542 	if (data) {
543 		atmci_set_pending(host, EVENT_XFER_COMPLETE);
544 		tasklet_schedule(&host->tasklet);
545 
546 		/*
547 		 * Regardless of what the documentation says, we have
548 		 * to wait for NOTBUSY even after block read
549 		 * operations.
550 		 *
551 		 * When the DMA transfer is complete, the controller
552 		 * may still be reading the CRC from the card, i.e.
553 		 * the data transfer is still in progress and we
554 		 * haven't seen all the potential error bits yet.
555 		 *
556 		 * The interrupt handler will schedule a different
557 		 * tasklet to finish things up when the data transfer
558 		 * is completely done.
559 		 *
560 		 * We may not complete the mmc request here anyway
561 		 * because the mmc layer may call back and cause us to
562 		 * violate the "don't submit new operations from the
563 		 * completion callback" rule of the dma engine
564 		 * framework.
565 		 */
566 		mci_writel(host, IER, MCI_NOTBUSY);
567 	}
568 }
569 
570 static int
571 atmci_submit_data_dma(struct atmel_mci *host, struct mmc_data *data)
572 {
573 	struct dma_chan			*chan;
574 	struct dma_async_tx_descriptor	*desc;
575 	struct scatterlist		*sg;
576 	unsigned int			i;
577 	enum dma_data_direction		direction;
578 
579 	/*
580 	 * We don't do DMA on "complex" transfers, i.e. with
581 	 * non-word-aligned buffers or lengths. Also, we don't bother
582 	 * with all the DMA setup overhead for short transfers.
583 	 */
584 	if (data->blocks * data->blksz < ATMCI_DMA_THRESHOLD)
585 		return -EINVAL;
586 	if (data->blksz & 3)
587 		return -EINVAL;
588 
589 	for_each_sg(data->sg, sg, data->sg_len, i) {
590 		if (sg->offset & 3 || sg->length & 3)
591 			return -EINVAL;
592 	}
593 
594 	/* If we don't have a channel, we can't do DMA */
595 	chan = host->dma.chan;
596 	if (chan) {
597 		dma_chan_get(chan);
598 		host->data_chan = chan;
599 	}
600 
601 	if (!chan)
602 		return -ENODEV;
603 
604 	if (data->flags & MMC_DATA_READ)
605 		direction = DMA_FROM_DEVICE;
606 	else
607 		direction = DMA_TO_DEVICE;
608 
609 	desc = chan->device->device_prep_slave_sg(chan,
610 			data->sg, data->sg_len, direction,
611 			DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
612 	if (!desc)
613 		return -ENOMEM;
614 
615 	host->dma.data_desc = desc;
616 	desc->callback = atmci_dma_complete;
617 	desc->callback_param = host;
618 	desc->tx_submit(desc);
619 
620 	/* Go! */
621 	chan->device->device_issue_pending(chan);
622 
623 	return 0;
624 }
625 
626 #else /* CONFIG_MMC_ATMELMCI_DMA */
627 
628 static int atmci_submit_data_dma(struct atmel_mci *host, struct mmc_data *data)
629 {
630 	return -ENOSYS;
631 }
632 
633 static void atmci_stop_dma(struct atmel_mci *host)
634 {
635 	/* Data transfer was stopped by the interrupt handler */
636 	atmci_set_pending(host, EVENT_XFER_COMPLETE);
637 	mci_writel(host, IER, MCI_NOTBUSY);
638 }
639 
640 #endif /* CONFIG_MMC_ATMELMCI_DMA */
641 
642 /*
643  * Returns a mask of interrupt flags to be enabled after the whole
644  * request has been prepared.
645  */
646 static u32 atmci_submit_data(struct atmel_mci *host, struct mmc_data *data)
647 {
648 	u32 iflags;
649 
650 	data->error = -EINPROGRESS;
651 
652 	WARN_ON(host->data);
653 	host->sg = NULL;
654 	host->data = data;
655 
656 	iflags = ATMCI_DATA_ERROR_FLAGS;
657 	if (atmci_submit_data_dma(host, data)) {
658 		host->data_chan = NULL;
659 
660 		/*
661 		 * Errata: MMC data write operation with less than 12
662 		 * bytes is impossible.
663 		 *
664 		 * Errata: MCI Transmit Data Register (TDR) FIFO
665 		 * corruption when length is not multiple of 4.
666 		 */
667 		if (data->blocks * data->blksz < 12
668 				|| (data->blocks * data->blksz) & 3)
669 			host->need_reset = true;
670 
671 		host->sg = data->sg;
672 		host->pio_offset = 0;
673 		if (data->flags & MMC_DATA_READ)
674 			iflags |= MCI_RXRDY;
675 		else
676 			iflags |= MCI_TXRDY;
677 	}
678 
679 	return iflags;
680 }
681 
682 static void atmci_start_request(struct atmel_mci *host,
683 		struct atmel_mci_slot *slot)
684 {
685 	struct mmc_request	*mrq;
686 	struct mmc_command	*cmd;
687 	struct mmc_data		*data;
688 	u32			iflags;
689 	u32			cmdflags;
690 
691 	mrq = slot->mrq;
692 	host->cur_slot = slot;
693 	host->mrq = mrq;
694 
695 	host->pending_events = 0;
696 	host->completed_events = 0;
697 	host->data_status = 0;
698 
699 	if (host->need_reset) {
700 		mci_writel(host, CR, MCI_CR_SWRST);
701 		mci_writel(host, CR, MCI_CR_MCIEN);
702 		mci_writel(host, MR, host->mode_reg);
703 		host->need_reset = false;
704 	}
705 	mci_writel(host, SDCR, slot->sdc_reg);
706 
707 	iflags = mci_readl(host, IMR);
708 	if (iflags)
709 		dev_warn(&slot->mmc->class_dev, "WARNING: IMR=0x%08x\n",
710 				iflags);
711 
712 	if (unlikely(test_and_clear_bit(ATMCI_CARD_NEED_INIT, &slot->flags))) {
713 		/* Send init sequence (74 clock cycles) */
714 		mci_writel(host, CMDR, MCI_CMDR_SPCMD_INIT);
715 		while (!(mci_readl(host, SR) & MCI_CMDRDY))
716 			cpu_relax();
717 	}
718 	data = mrq->data;
719 	if (data) {
720 		atmci_set_timeout(host, slot, data);
721 
722 		/* Must set block count/size before sending command */
723 		mci_writel(host, BLKR, MCI_BCNT(data->blocks)
724 				| MCI_BLKLEN(data->blksz));
725 		dev_vdbg(&slot->mmc->class_dev, "BLKR=0x%08x\n",
726 			MCI_BCNT(data->blocks) | MCI_BLKLEN(data->blksz));
727 	}
728 
729 	iflags = MCI_CMDRDY;
730 	cmd = mrq->cmd;
731 	cmdflags = atmci_prepare_command(slot->mmc, cmd);
732 	atmci_start_command(host, cmd, cmdflags);
733 
734 	if (data)
735 		iflags |= atmci_submit_data(host, data);
736 
737 	if (mrq->stop) {
738 		host->stop_cmdr = atmci_prepare_command(slot->mmc, mrq->stop);
739 		host->stop_cmdr |= MCI_CMDR_STOP_XFER;
740 		if (!(data->flags & MMC_DATA_WRITE))
741 			host->stop_cmdr |= MCI_CMDR_TRDIR_READ;
742 		if (data->flags & MMC_DATA_STREAM)
743 			host->stop_cmdr |= MCI_CMDR_STREAM;
744 		else
745 			host->stop_cmdr |= MCI_CMDR_MULTI_BLOCK;
746 	}
747 
748 	/*
749 	 * We could have enabled interrupts earlier, but I suspect
750 	 * that would open up a nice can of interesting race
751 	 * conditions (e.g. command and data complete, but stop not
752 	 * prepared yet.)
753 	 */
754 	mci_writel(host, IER, iflags);
755 }
756 
757 static void atmci_queue_request(struct atmel_mci *host,
758 		struct atmel_mci_slot *slot, struct mmc_request *mrq)
759 {
760 	dev_vdbg(&slot->mmc->class_dev, "queue request: state=%d\n",
761 			host->state);
762 
763 	spin_lock_bh(&host->lock);
764 	slot->mrq = mrq;
765 	if (host->state == STATE_IDLE) {
766 		host->state = STATE_SENDING_CMD;
767 		atmci_start_request(host, slot);
768 	} else {
769 		list_add_tail(&slot->queue_node, &host->queue);
770 	}
771 	spin_unlock_bh(&host->lock);
772 }
773 
774 static void atmci_request(struct mmc_host *mmc, struct mmc_request *mrq)
775 {
776 	struct atmel_mci_slot	*slot = mmc_priv(mmc);
777 	struct atmel_mci	*host = slot->host;
778 	struct mmc_data		*data;
779 
780 	WARN_ON(slot->mrq);
781 
782 	/*
783 	 * We may "know" the card is gone even though there's still an
784 	 * electrical connection. If so, we really need to communicate
785 	 * this to the MMC core since there won't be any more
786 	 * interrupts as the card is completely removed. Otherwise,
787 	 * the MMC core might believe the card is still there even
788 	 * though the card was just removed very slowly.
789 	 */
790 	if (!test_bit(ATMCI_CARD_PRESENT, &slot->flags)) {
791 		mrq->cmd->error = -ENOMEDIUM;
792 		mmc_request_done(mmc, mrq);
793 		return;
794 	}
795 
796 	/* We don't support multiple blocks of weird lengths. */
797 	data = mrq->data;
798 	if (data && data->blocks > 1 && data->blksz & 3) {
799 		mrq->cmd->error = -EINVAL;
800 		mmc_request_done(mmc, mrq);
801 	}
802 
803 	atmci_queue_request(host, slot, mrq);
804 }
805 
806 static void atmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
807 {
808 	struct atmel_mci_slot	*slot = mmc_priv(mmc);
809 	struct atmel_mci	*host = slot->host;
810 	unsigned int		i;
811 
812 	slot->sdc_reg &= ~MCI_SDCBUS_MASK;
813 	switch (ios->bus_width) {
814 	case MMC_BUS_WIDTH_1:
815 		slot->sdc_reg |= MCI_SDCBUS_1BIT;
816 		break;
817 	case MMC_BUS_WIDTH_4:
818 		slot->sdc_reg = MCI_SDCBUS_4BIT;
819 		break;
820 	}
821 
822 	if (ios->clock) {
823 		unsigned int clock_min = ~0U;
824 		u32 clkdiv;
825 
826 		spin_lock_bh(&host->lock);
827 		if (!host->mode_reg) {
828 			clk_enable(host->mck);
829 			mci_writel(host, CR, MCI_CR_SWRST);
830 			mci_writel(host, CR, MCI_CR_MCIEN);
831 		}
832 
833 		/*
834 		 * Use mirror of ios->clock to prevent race with mmc
835 		 * core ios update when finding the minimum.
836 		 */
837 		slot->clock = ios->clock;
838 		for (i = 0; i < ATMEL_MCI_MAX_NR_SLOTS; i++) {
839 			if (host->slot[i] && host->slot[i]->clock
840 					&& host->slot[i]->clock < clock_min)
841 				clock_min = host->slot[i]->clock;
842 		}
843 
844 		/* Calculate clock divider */
845 		clkdiv = DIV_ROUND_UP(host->bus_hz, 2 * clock_min) - 1;
846 		if (clkdiv > 255) {
847 			dev_warn(&mmc->class_dev,
848 				"clock %u too slow; using %lu\n",
849 				clock_min, host->bus_hz / (2 * 256));
850 			clkdiv = 255;
851 		}
852 
853 		/*
854 		 * WRPROOF and RDPROOF prevent overruns/underruns by
855 		 * stopping the clock when the FIFO is full/empty.
856 		 * This state is not expected to last for long.
857 		 */
858 		host->mode_reg = MCI_MR_CLKDIV(clkdiv) | MCI_MR_WRPROOF
859 					| MCI_MR_RDPROOF;
860 
861 		if (list_empty(&host->queue))
862 			mci_writel(host, MR, host->mode_reg);
863 		else
864 			host->need_clock_update = true;
865 
866 		spin_unlock_bh(&host->lock);
867 	} else {
868 		bool any_slot_active = false;
869 
870 		spin_lock_bh(&host->lock);
871 		slot->clock = 0;
872 		for (i = 0; i < ATMEL_MCI_MAX_NR_SLOTS; i++) {
873 			if (host->slot[i] && host->slot[i]->clock) {
874 				any_slot_active = true;
875 				break;
876 			}
877 		}
878 		if (!any_slot_active) {
879 			mci_writel(host, CR, MCI_CR_MCIDIS);
880 			if (host->mode_reg) {
881 				mci_readl(host, MR);
882 				clk_disable(host->mck);
883 			}
884 			host->mode_reg = 0;
885 		}
886 		spin_unlock_bh(&host->lock);
887 	}
888 
889 	switch (ios->power_mode) {
890 	case MMC_POWER_UP:
891 		set_bit(ATMCI_CARD_NEED_INIT, &slot->flags);
892 		break;
893 	default:
894 		/*
895 		 * TODO: None of the currently available AVR32-based
896 		 * boards allow MMC power to be turned off. Implement
897 		 * power control when this can be tested properly.
898 		 *
899 		 * We also need to hook this into the clock management
900 		 * somehow so that newly inserted cards aren't
901 		 * subjected to a fast clock before we have a chance
902 		 * to figure out what the maximum rate is. Currently,
903 		 * there's no way to avoid this, and there never will
904 		 * be for boards that don't support power control.
905 		 */
906 		break;
907 	}
908 }
909 
910 static int atmci_get_ro(struct mmc_host *mmc)
911 {
912 	int			read_only = -ENOSYS;
913 	struct atmel_mci_slot	*slot = mmc_priv(mmc);
914 
915 	if (gpio_is_valid(slot->wp_pin)) {
916 		read_only = gpio_get_value(slot->wp_pin);
917 		dev_dbg(&mmc->class_dev, "card is %s\n",
918 				read_only ? "read-only" : "read-write");
919 	}
920 
921 	return read_only;
922 }
923 
924 static int atmci_get_cd(struct mmc_host *mmc)
925 {
926 	int			present = -ENOSYS;
927 	struct atmel_mci_slot	*slot = mmc_priv(mmc);
928 
929 	if (gpio_is_valid(slot->detect_pin)) {
930 		present = !gpio_get_value(slot->detect_pin);
931 		dev_dbg(&mmc->class_dev, "card is %spresent\n",
932 				present ? "" : "not ");
933 	}
934 
935 	return present;
936 }
937 
938 static const struct mmc_host_ops atmci_ops = {
939 	.request	= atmci_request,
940 	.set_ios	= atmci_set_ios,
941 	.get_ro		= atmci_get_ro,
942 	.get_cd		= atmci_get_cd,
943 };
944 
945 /* Called with host->lock held */
946 static void atmci_request_end(struct atmel_mci *host, struct mmc_request *mrq)
947 	__releases(&host->lock)
948 	__acquires(&host->lock)
949 {
950 	struct atmel_mci_slot	*slot = NULL;
951 	struct mmc_host		*prev_mmc = host->cur_slot->mmc;
952 
953 	WARN_ON(host->cmd || host->data);
954 
955 	/*
956 	 * Update the MMC clock rate if necessary. This may be
957 	 * necessary if set_ios() is called when a different slot is
958 	 * busy transfering data.
959 	 */
960 	if (host->need_clock_update)
961 		mci_writel(host, MR, host->mode_reg);
962 
963 	host->cur_slot->mrq = NULL;
964 	host->mrq = NULL;
965 	if (!list_empty(&host->queue)) {
966 		slot = list_entry(host->queue.next,
967 				struct atmel_mci_slot, queue_node);
968 		list_del(&slot->queue_node);
969 		dev_vdbg(&host->pdev->dev, "list not empty: %s is next\n",
970 				mmc_hostname(slot->mmc));
971 		host->state = STATE_SENDING_CMD;
972 		atmci_start_request(host, slot);
973 	} else {
974 		dev_vdbg(&host->pdev->dev, "list empty\n");
975 		host->state = STATE_IDLE;
976 	}
977 
978 	spin_unlock(&host->lock);
979 	mmc_request_done(prev_mmc, mrq);
980 	spin_lock(&host->lock);
981 }
982 
983 static void atmci_command_complete(struct atmel_mci *host,
984 			struct mmc_command *cmd)
985 {
986 	u32		status = host->cmd_status;
987 
988 	/* Read the response from the card (up to 16 bytes) */
989 	cmd->resp[0] = mci_readl(host, RSPR);
990 	cmd->resp[1] = mci_readl(host, RSPR);
991 	cmd->resp[2] = mci_readl(host, RSPR);
992 	cmd->resp[3] = mci_readl(host, RSPR);
993 
994 	if (status & MCI_RTOE)
995 		cmd->error = -ETIMEDOUT;
996 	else if ((cmd->flags & MMC_RSP_CRC) && (status & MCI_RCRCE))
997 		cmd->error = -EILSEQ;
998 	else if (status & (MCI_RINDE | MCI_RDIRE | MCI_RENDE))
999 		cmd->error = -EIO;
1000 	else
1001 		cmd->error = 0;
1002 
1003 	if (cmd->error) {
1004 		dev_dbg(&host->pdev->dev,
1005 			"command error: status=0x%08x\n", status);
1006 
1007 		if (cmd->data) {
1008 			host->data = NULL;
1009 			atmci_stop_dma(host);
1010 			mci_writel(host, IDR, MCI_NOTBUSY
1011 					| MCI_TXRDY | MCI_RXRDY
1012 					| ATMCI_DATA_ERROR_FLAGS);
1013 		}
1014 	}
1015 }
1016 
1017 static void atmci_detect_change(unsigned long data)
1018 {
1019 	struct atmel_mci_slot	*slot = (struct atmel_mci_slot *)data;
1020 	bool			present;
1021 	bool			present_old;
1022 
1023 	/*
1024 	 * atmci_cleanup_slot() sets the ATMCI_SHUTDOWN flag before
1025 	 * freeing the interrupt. We must not re-enable the interrupt
1026 	 * if it has been freed, and if we're shutting down, it
1027 	 * doesn't really matter whether the card is present or not.
1028 	 */
1029 	smp_rmb();
1030 	if (test_bit(ATMCI_SHUTDOWN, &slot->flags))
1031 		return;
1032 
1033 	enable_irq(gpio_to_irq(slot->detect_pin));
1034 	present = !gpio_get_value(slot->detect_pin);
1035 	present_old = test_bit(ATMCI_CARD_PRESENT, &slot->flags);
1036 
1037 	dev_vdbg(&slot->mmc->class_dev, "detect change: %d (was %d)\n",
1038 			present, present_old);
1039 
1040 	if (present != present_old) {
1041 		struct atmel_mci	*host = slot->host;
1042 		struct mmc_request	*mrq;
1043 
1044 		dev_dbg(&slot->mmc->class_dev, "card %s\n",
1045 			present ? "inserted" : "removed");
1046 
1047 		spin_lock(&host->lock);
1048 
1049 		if (!present)
1050 			clear_bit(ATMCI_CARD_PRESENT, &slot->flags);
1051 		else
1052 			set_bit(ATMCI_CARD_PRESENT, &slot->flags);
1053 
1054 		/* Clean up queue if present */
1055 		mrq = slot->mrq;
1056 		if (mrq) {
1057 			if (mrq == host->mrq) {
1058 				/*
1059 				 * Reset controller to terminate any ongoing
1060 				 * commands or data transfers.
1061 				 */
1062 				mci_writel(host, CR, MCI_CR_SWRST);
1063 				mci_writel(host, CR, MCI_CR_MCIEN);
1064 				mci_writel(host, MR, host->mode_reg);
1065 
1066 				host->data = NULL;
1067 				host->cmd = NULL;
1068 
1069 				switch (host->state) {
1070 				case STATE_IDLE:
1071 					break;
1072 				case STATE_SENDING_CMD:
1073 					mrq->cmd->error = -ENOMEDIUM;
1074 					if (!mrq->data)
1075 						break;
1076 					/* fall through */
1077 				case STATE_SENDING_DATA:
1078 					mrq->data->error = -ENOMEDIUM;
1079 					atmci_stop_dma(host);
1080 					break;
1081 				case STATE_DATA_BUSY:
1082 				case STATE_DATA_ERROR:
1083 					if (mrq->data->error == -EINPROGRESS)
1084 						mrq->data->error = -ENOMEDIUM;
1085 					if (!mrq->stop)
1086 						break;
1087 					/* fall through */
1088 				case STATE_SENDING_STOP:
1089 					mrq->stop->error = -ENOMEDIUM;
1090 					break;
1091 				}
1092 
1093 				atmci_request_end(host, mrq);
1094 			} else {
1095 				list_del(&slot->queue_node);
1096 				mrq->cmd->error = -ENOMEDIUM;
1097 				if (mrq->data)
1098 					mrq->data->error = -ENOMEDIUM;
1099 				if (mrq->stop)
1100 					mrq->stop->error = -ENOMEDIUM;
1101 
1102 				spin_unlock(&host->lock);
1103 				mmc_request_done(slot->mmc, mrq);
1104 				spin_lock(&host->lock);
1105 			}
1106 		}
1107 		spin_unlock(&host->lock);
1108 
1109 		mmc_detect_change(slot->mmc, 0);
1110 	}
1111 }
1112 
1113 static void atmci_tasklet_func(unsigned long priv)
1114 {
1115 	struct atmel_mci	*host = (struct atmel_mci *)priv;
1116 	struct mmc_request	*mrq = host->mrq;
1117 	struct mmc_data		*data = host->data;
1118 	struct mmc_command	*cmd = host->cmd;
1119 	enum atmel_mci_state	state = host->state;
1120 	enum atmel_mci_state	prev_state;
1121 	u32			status;
1122 
1123 	spin_lock(&host->lock);
1124 
1125 	state = host->state;
1126 
1127 	dev_vdbg(&host->pdev->dev,
1128 		"tasklet: state %u pending/completed/mask %lx/%lx/%x\n",
1129 		state, host->pending_events, host->completed_events,
1130 		mci_readl(host, IMR));
1131 
1132 	do {
1133 		prev_state = state;
1134 
1135 		switch (state) {
1136 		case STATE_IDLE:
1137 			break;
1138 
1139 		case STATE_SENDING_CMD:
1140 			if (!atmci_test_and_clear_pending(host,
1141 						EVENT_CMD_COMPLETE))
1142 				break;
1143 
1144 			host->cmd = NULL;
1145 			atmci_set_completed(host, EVENT_CMD_COMPLETE);
1146 			atmci_command_complete(host, mrq->cmd);
1147 			if (!mrq->data || cmd->error) {
1148 				atmci_request_end(host, host->mrq);
1149 				goto unlock;
1150 			}
1151 
1152 			prev_state = state = STATE_SENDING_DATA;
1153 			/* fall through */
1154 
1155 		case STATE_SENDING_DATA:
1156 			if (atmci_test_and_clear_pending(host,
1157 						EVENT_DATA_ERROR)) {
1158 				atmci_stop_dma(host);
1159 				if (data->stop)
1160 					send_stop_cmd(host, data);
1161 				state = STATE_DATA_ERROR;
1162 				break;
1163 			}
1164 
1165 			if (!atmci_test_and_clear_pending(host,
1166 						EVENT_XFER_COMPLETE))
1167 				break;
1168 
1169 			atmci_set_completed(host, EVENT_XFER_COMPLETE);
1170 			prev_state = state = STATE_DATA_BUSY;
1171 			/* fall through */
1172 
1173 		case STATE_DATA_BUSY:
1174 			if (!atmci_test_and_clear_pending(host,
1175 						EVENT_DATA_COMPLETE))
1176 				break;
1177 
1178 			host->data = NULL;
1179 			atmci_set_completed(host, EVENT_DATA_COMPLETE);
1180 			status = host->data_status;
1181 			if (unlikely(status & ATMCI_DATA_ERROR_FLAGS)) {
1182 				if (status & MCI_DTOE) {
1183 					dev_dbg(&host->pdev->dev,
1184 							"data timeout error\n");
1185 					data->error = -ETIMEDOUT;
1186 				} else if (status & MCI_DCRCE) {
1187 					dev_dbg(&host->pdev->dev,
1188 							"data CRC error\n");
1189 					data->error = -EILSEQ;
1190 				} else {
1191 					dev_dbg(&host->pdev->dev,
1192 						"data FIFO error (status=%08x)\n",
1193 						status);
1194 					data->error = -EIO;
1195 				}
1196 			} else {
1197 				data->bytes_xfered = data->blocks * data->blksz;
1198 				data->error = 0;
1199 			}
1200 
1201 			if (!data->stop) {
1202 				atmci_request_end(host, host->mrq);
1203 				goto unlock;
1204 			}
1205 
1206 			prev_state = state = STATE_SENDING_STOP;
1207 			if (!data->error)
1208 				send_stop_cmd(host, data);
1209 			/* fall through */
1210 
1211 		case STATE_SENDING_STOP:
1212 			if (!atmci_test_and_clear_pending(host,
1213 						EVENT_CMD_COMPLETE))
1214 				break;
1215 
1216 			host->cmd = NULL;
1217 			atmci_command_complete(host, mrq->stop);
1218 			atmci_request_end(host, host->mrq);
1219 			goto unlock;
1220 
1221 		case STATE_DATA_ERROR:
1222 			if (!atmci_test_and_clear_pending(host,
1223 						EVENT_XFER_COMPLETE))
1224 				break;
1225 
1226 			state = STATE_DATA_BUSY;
1227 			break;
1228 		}
1229 	} while (state != prev_state);
1230 
1231 	host->state = state;
1232 
1233 unlock:
1234 	spin_unlock(&host->lock);
1235 }
1236 
1237 static void atmci_read_data_pio(struct atmel_mci *host)
1238 {
1239 	struct scatterlist	*sg = host->sg;
1240 	void			*buf = sg_virt(sg);
1241 	unsigned int		offset = host->pio_offset;
1242 	struct mmc_data		*data = host->data;
1243 	u32			value;
1244 	u32			status;
1245 	unsigned int		nbytes = 0;
1246 
1247 	do {
1248 		value = mci_readl(host, RDR);
1249 		if (likely(offset + 4 <= sg->length)) {
1250 			put_unaligned(value, (u32 *)(buf + offset));
1251 
1252 			offset += 4;
1253 			nbytes += 4;
1254 
1255 			if (offset == sg->length) {
1256 				flush_dcache_page(sg_page(sg));
1257 				host->sg = sg = sg_next(sg);
1258 				if (!sg)
1259 					goto done;
1260 
1261 				offset = 0;
1262 				buf = sg_virt(sg);
1263 			}
1264 		} else {
1265 			unsigned int remaining = sg->length - offset;
1266 			memcpy(buf + offset, &value, remaining);
1267 			nbytes += remaining;
1268 
1269 			flush_dcache_page(sg_page(sg));
1270 			host->sg = sg = sg_next(sg);
1271 			if (!sg)
1272 				goto done;
1273 
1274 			offset = 4 - remaining;
1275 			buf = sg_virt(sg);
1276 			memcpy(buf, (u8 *)&value + remaining, offset);
1277 			nbytes += offset;
1278 		}
1279 
1280 		status = mci_readl(host, SR);
1281 		if (status & ATMCI_DATA_ERROR_FLAGS) {
1282 			mci_writel(host, IDR, (MCI_NOTBUSY | MCI_RXRDY
1283 						| ATMCI_DATA_ERROR_FLAGS));
1284 			host->data_status = status;
1285 			data->bytes_xfered += nbytes;
1286 			smp_wmb();
1287 			atmci_set_pending(host, EVENT_DATA_ERROR);
1288 			tasklet_schedule(&host->tasklet);
1289 			return;
1290 		}
1291 	} while (status & MCI_RXRDY);
1292 
1293 	host->pio_offset = offset;
1294 	data->bytes_xfered += nbytes;
1295 
1296 	return;
1297 
1298 done:
1299 	mci_writel(host, IDR, MCI_RXRDY);
1300 	mci_writel(host, IER, MCI_NOTBUSY);
1301 	data->bytes_xfered += nbytes;
1302 	smp_wmb();
1303 	atmci_set_pending(host, EVENT_XFER_COMPLETE);
1304 }
1305 
1306 static void atmci_write_data_pio(struct atmel_mci *host)
1307 {
1308 	struct scatterlist	*sg = host->sg;
1309 	void			*buf = sg_virt(sg);
1310 	unsigned int		offset = host->pio_offset;
1311 	struct mmc_data		*data = host->data;
1312 	u32			value;
1313 	u32			status;
1314 	unsigned int		nbytes = 0;
1315 
1316 	do {
1317 		if (likely(offset + 4 <= sg->length)) {
1318 			value = get_unaligned((u32 *)(buf + offset));
1319 			mci_writel(host, TDR, value);
1320 
1321 			offset += 4;
1322 			nbytes += 4;
1323 			if (offset == sg->length) {
1324 				host->sg = sg = sg_next(sg);
1325 				if (!sg)
1326 					goto done;
1327 
1328 				offset = 0;
1329 				buf = sg_virt(sg);
1330 			}
1331 		} else {
1332 			unsigned int remaining = sg->length - offset;
1333 
1334 			value = 0;
1335 			memcpy(&value, buf + offset, remaining);
1336 			nbytes += remaining;
1337 
1338 			host->sg = sg = sg_next(sg);
1339 			if (!sg) {
1340 				mci_writel(host, TDR, value);
1341 				goto done;
1342 			}
1343 
1344 			offset = 4 - remaining;
1345 			buf = sg_virt(sg);
1346 			memcpy((u8 *)&value + remaining, buf, offset);
1347 			mci_writel(host, TDR, value);
1348 			nbytes += offset;
1349 		}
1350 
1351 		status = mci_readl(host, SR);
1352 		if (status & ATMCI_DATA_ERROR_FLAGS) {
1353 			mci_writel(host, IDR, (MCI_NOTBUSY | MCI_TXRDY
1354 						| ATMCI_DATA_ERROR_FLAGS));
1355 			host->data_status = status;
1356 			data->bytes_xfered += nbytes;
1357 			smp_wmb();
1358 			atmci_set_pending(host, EVENT_DATA_ERROR);
1359 			tasklet_schedule(&host->tasklet);
1360 			return;
1361 		}
1362 	} while (status & MCI_TXRDY);
1363 
1364 	host->pio_offset = offset;
1365 	data->bytes_xfered += nbytes;
1366 
1367 	return;
1368 
1369 done:
1370 	mci_writel(host, IDR, MCI_TXRDY);
1371 	mci_writel(host, IER, MCI_NOTBUSY);
1372 	data->bytes_xfered += nbytes;
1373 	smp_wmb();
1374 	atmci_set_pending(host, EVENT_XFER_COMPLETE);
1375 }
1376 
1377 static void atmci_cmd_interrupt(struct atmel_mci *host, u32 status)
1378 {
1379 	mci_writel(host, IDR, MCI_CMDRDY);
1380 
1381 	host->cmd_status = status;
1382 	smp_wmb();
1383 	atmci_set_pending(host, EVENT_CMD_COMPLETE);
1384 	tasklet_schedule(&host->tasklet);
1385 }
1386 
1387 static irqreturn_t atmci_interrupt(int irq, void *dev_id)
1388 {
1389 	struct atmel_mci	*host = dev_id;
1390 	u32			status, mask, pending;
1391 	unsigned int		pass_count = 0;
1392 
1393 	do {
1394 		status = mci_readl(host, SR);
1395 		mask = mci_readl(host, IMR);
1396 		pending = status & mask;
1397 		if (!pending)
1398 			break;
1399 
1400 		if (pending & ATMCI_DATA_ERROR_FLAGS) {
1401 			mci_writel(host, IDR, ATMCI_DATA_ERROR_FLAGS
1402 					| MCI_RXRDY | MCI_TXRDY);
1403 			pending &= mci_readl(host, IMR);
1404 
1405 			host->data_status = status;
1406 			smp_wmb();
1407 			atmci_set_pending(host, EVENT_DATA_ERROR);
1408 			tasklet_schedule(&host->tasklet);
1409 		}
1410 		if (pending & MCI_NOTBUSY) {
1411 			mci_writel(host, IDR,
1412 					ATMCI_DATA_ERROR_FLAGS | MCI_NOTBUSY);
1413 			if (!host->data_status)
1414 				host->data_status = status;
1415 			smp_wmb();
1416 			atmci_set_pending(host, EVENT_DATA_COMPLETE);
1417 			tasklet_schedule(&host->tasklet);
1418 		}
1419 		if (pending & MCI_RXRDY)
1420 			atmci_read_data_pio(host);
1421 		if (pending & MCI_TXRDY)
1422 			atmci_write_data_pio(host);
1423 
1424 		if (pending & MCI_CMDRDY)
1425 			atmci_cmd_interrupt(host, status);
1426 	} while (pass_count++ < 5);
1427 
1428 	return pass_count ? IRQ_HANDLED : IRQ_NONE;
1429 }
1430 
1431 static irqreturn_t atmci_detect_interrupt(int irq, void *dev_id)
1432 {
1433 	struct atmel_mci_slot	*slot = dev_id;
1434 
1435 	/*
1436 	 * Disable interrupts until the pin has stabilized and check
1437 	 * the state then. Use mod_timer() since we may be in the
1438 	 * middle of the timer routine when this interrupt triggers.
1439 	 */
1440 	disable_irq_nosync(irq);
1441 	mod_timer(&slot->detect_timer, jiffies + msecs_to_jiffies(20));
1442 
1443 	return IRQ_HANDLED;
1444 }
1445 
1446 #ifdef CONFIG_MMC_ATMELMCI_DMA
1447 
1448 static inline struct atmel_mci *
1449 dma_client_to_atmel_mci(struct dma_client *client)
1450 {
1451 	return container_of(client, struct atmel_mci, dma.client);
1452 }
1453 
1454 static enum dma_state_client atmci_dma_event(struct dma_client *client,
1455 		struct dma_chan *chan, enum dma_state state)
1456 {
1457 	struct atmel_mci	*host;
1458 	enum dma_state_client	ret = DMA_NAK;
1459 
1460 	host = dma_client_to_atmel_mci(client);
1461 
1462 	switch (state) {
1463 	case DMA_RESOURCE_AVAILABLE:
1464 		spin_lock_bh(&host->lock);
1465 		if (!host->dma.chan) {
1466 			host->dma.chan = chan;
1467 			ret = DMA_ACK;
1468 		}
1469 		spin_unlock_bh(&host->lock);
1470 
1471 		if (ret == DMA_ACK)
1472 			dev_info(&host->pdev->dev,
1473 					"Using %s for DMA transfers\n",
1474 					chan->dev.bus_id);
1475 		break;
1476 
1477 	case DMA_RESOURCE_REMOVED:
1478 		spin_lock_bh(&host->lock);
1479 		if (host->dma.chan == chan) {
1480 			host->dma.chan = NULL;
1481 			ret = DMA_ACK;
1482 		}
1483 		spin_unlock_bh(&host->lock);
1484 
1485 		if (ret == DMA_ACK)
1486 			dev_info(&host->pdev->dev,
1487 					"Lost %s, falling back to PIO\n",
1488 					chan->dev.bus_id);
1489 		break;
1490 
1491 	default:
1492 		break;
1493 	}
1494 
1495 
1496 	return ret;
1497 }
1498 #endif /* CONFIG_MMC_ATMELMCI_DMA */
1499 
1500 static int __init atmci_init_slot(struct atmel_mci *host,
1501 		struct mci_slot_pdata *slot_data, unsigned int id,
1502 		u32 sdc_reg)
1503 {
1504 	struct mmc_host			*mmc;
1505 	struct atmel_mci_slot		*slot;
1506 
1507 	mmc = mmc_alloc_host(sizeof(struct atmel_mci_slot), &host->pdev->dev);
1508 	if (!mmc)
1509 		return -ENOMEM;
1510 
1511 	slot = mmc_priv(mmc);
1512 	slot->mmc = mmc;
1513 	slot->host = host;
1514 	slot->detect_pin = slot_data->detect_pin;
1515 	slot->wp_pin = slot_data->wp_pin;
1516 	slot->sdc_reg = sdc_reg;
1517 
1518 	mmc->ops = &atmci_ops;
1519 	mmc->f_min = DIV_ROUND_UP(host->bus_hz, 512);
1520 	mmc->f_max = host->bus_hz / 2;
1521 	mmc->ocr_avail	= MMC_VDD_32_33 | MMC_VDD_33_34;
1522 	if (slot_data->bus_width >= 4)
1523 		mmc->caps |= MMC_CAP_4_BIT_DATA;
1524 
1525 	mmc->max_hw_segs = 64;
1526 	mmc->max_phys_segs = 64;
1527 	mmc->max_req_size = 32768 * 512;
1528 	mmc->max_blk_size = 32768;
1529 	mmc->max_blk_count = 512;
1530 
1531 	/* Assume card is present initially */
1532 	set_bit(ATMCI_CARD_PRESENT, &slot->flags);
1533 	if (gpio_is_valid(slot->detect_pin)) {
1534 		if (gpio_request(slot->detect_pin, "mmc_detect")) {
1535 			dev_dbg(&mmc->class_dev, "no detect pin available\n");
1536 			slot->detect_pin = -EBUSY;
1537 		} else if (gpio_get_value(slot->detect_pin)) {
1538 			clear_bit(ATMCI_CARD_PRESENT, &slot->flags);
1539 		}
1540 	}
1541 
1542 	if (!gpio_is_valid(slot->detect_pin))
1543 		mmc->caps |= MMC_CAP_NEEDS_POLL;
1544 
1545 	if (gpio_is_valid(slot->wp_pin)) {
1546 		if (gpio_request(slot->wp_pin, "mmc_wp")) {
1547 			dev_dbg(&mmc->class_dev, "no WP pin available\n");
1548 			slot->wp_pin = -EBUSY;
1549 		}
1550 	}
1551 
1552 	host->slot[id] = slot;
1553 	mmc_add_host(mmc);
1554 
1555 	if (gpio_is_valid(slot->detect_pin)) {
1556 		int ret;
1557 
1558 		setup_timer(&slot->detect_timer, atmci_detect_change,
1559 				(unsigned long)slot);
1560 
1561 		ret = request_irq(gpio_to_irq(slot->detect_pin),
1562 				atmci_detect_interrupt,
1563 				IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,
1564 				"mmc-detect", slot);
1565 		if (ret) {
1566 			dev_dbg(&mmc->class_dev,
1567 				"could not request IRQ %d for detect pin\n",
1568 				gpio_to_irq(slot->detect_pin));
1569 			gpio_free(slot->detect_pin);
1570 			slot->detect_pin = -EBUSY;
1571 		}
1572 	}
1573 
1574 	atmci_init_debugfs(slot);
1575 
1576 	return 0;
1577 }
1578 
1579 static void __exit atmci_cleanup_slot(struct atmel_mci_slot *slot,
1580 		unsigned int id)
1581 {
1582 	/* Debugfs stuff is cleaned up by mmc core */
1583 
1584 	set_bit(ATMCI_SHUTDOWN, &slot->flags);
1585 	smp_wmb();
1586 
1587 	mmc_remove_host(slot->mmc);
1588 
1589 	if (gpio_is_valid(slot->detect_pin)) {
1590 		int pin = slot->detect_pin;
1591 
1592 		free_irq(gpio_to_irq(pin), slot);
1593 		del_timer_sync(&slot->detect_timer);
1594 		gpio_free(pin);
1595 	}
1596 	if (gpio_is_valid(slot->wp_pin))
1597 		gpio_free(slot->wp_pin);
1598 
1599 	slot->host->slot[id] = NULL;
1600 	mmc_free_host(slot->mmc);
1601 }
1602 
1603 static int __init atmci_probe(struct platform_device *pdev)
1604 {
1605 	struct mci_platform_data	*pdata;
1606 	struct atmel_mci		*host;
1607 	struct resource			*regs;
1608 	unsigned int			nr_slots;
1609 	int				irq;
1610 	int				ret;
1611 
1612 	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1613 	if (!regs)
1614 		return -ENXIO;
1615 	pdata = pdev->dev.platform_data;
1616 	if (!pdata)
1617 		return -ENXIO;
1618 	irq = platform_get_irq(pdev, 0);
1619 	if (irq < 0)
1620 		return irq;
1621 
1622 	host = kzalloc(sizeof(struct atmel_mci), GFP_KERNEL);
1623 	if (!host)
1624 		return -ENOMEM;
1625 
1626 	host->pdev = pdev;
1627 	spin_lock_init(&host->lock);
1628 	INIT_LIST_HEAD(&host->queue);
1629 
1630 	host->mck = clk_get(&pdev->dev, "mci_clk");
1631 	if (IS_ERR(host->mck)) {
1632 		ret = PTR_ERR(host->mck);
1633 		goto err_clk_get;
1634 	}
1635 
1636 	ret = -ENOMEM;
1637 	host->regs = ioremap(regs->start, regs->end - regs->start + 1);
1638 	if (!host->regs)
1639 		goto err_ioremap;
1640 
1641 	clk_enable(host->mck);
1642 	mci_writel(host, CR, MCI_CR_SWRST);
1643 	host->bus_hz = clk_get_rate(host->mck);
1644 	clk_disable(host->mck);
1645 
1646 	host->mapbase = regs->start;
1647 
1648 	tasklet_init(&host->tasklet, atmci_tasklet_func, (unsigned long)host);
1649 
1650 	ret = request_irq(irq, atmci_interrupt, 0, pdev->dev.bus_id, host);
1651 	if (ret)
1652 		goto err_request_irq;
1653 
1654 #ifdef CONFIG_MMC_ATMELMCI_DMA
1655 	if (pdata->dma_slave) {
1656 		struct dma_slave *slave = pdata->dma_slave;
1657 
1658 		slave->tx_reg = regs->start + MCI_TDR;
1659 		slave->rx_reg = regs->start + MCI_RDR;
1660 
1661 		/* Try to grab a DMA channel */
1662 		host->dma.client.event_callback = atmci_dma_event;
1663 		dma_cap_set(DMA_SLAVE, host->dma.client.cap_mask);
1664 		host->dma.client.slave = slave;
1665 
1666 		dma_async_client_register(&host->dma.client);
1667 		dma_async_client_chan_request(&host->dma.client);
1668 	} else {
1669 		dev_notice(&pdev->dev, "DMA not available, using PIO\n");
1670 	}
1671 #endif /* CONFIG_MMC_ATMELMCI_DMA */
1672 
1673 	platform_set_drvdata(pdev, host);
1674 
1675 	/* We need at least one slot to succeed */
1676 	nr_slots = 0;
1677 	ret = -ENODEV;
1678 	if (pdata->slot[0].bus_width) {
1679 		ret = atmci_init_slot(host, &pdata->slot[0],
1680 				MCI_SDCSEL_SLOT_A, 0);
1681 		if (!ret)
1682 			nr_slots++;
1683 	}
1684 	if (pdata->slot[1].bus_width) {
1685 		ret = atmci_init_slot(host, &pdata->slot[1],
1686 				MCI_SDCSEL_SLOT_B, 1);
1687 		if (!ret)
1688 			nr_slots++;
1689 	}
1690 
1691 	if (!nr_slots)
1692 		goto err_init_slot;
1693 
1694 	dev_info(&pdev->dev,
1695 			"Atmel MCI controller at 0x%08lx irq %d, %u slots\n",
1696 			host->mapbase, irq, nr_slots);
1697 
1698 	return 0;
1699 
1700 err_init_slot:
1701 #ifdef CONFIG_MMC_ATMELMCI_DMA
1702 	if (pdata->dma_slave)
1703 		dma_async_client_unregister(&host->dma.client);
1704 #endif
1705 	free_irq(irq, host);
1706 err_request_irq:
1707 	iounmap(host->regs);
1708 err_ioremap:
1709 	clk_put(host->mck);
1710 err_clk_get:
1711 	kfree(host);
1712 	return ret;
1713 }
1714 
1715 static int __exit atmci_remove(struct platform_device *pdev)
1716 {
1717 	struct atmel_mci	*host = platform_get_drvdata(pdev);
1718 	unsigned int		i;
1719 
1720 	platform_set_drvdata(pdev, NULL);
1721 
1722 	for (i = 0; i < ATMEL_MCI_MAX_NR_SLOTS; i++) {
1723 		if (host->slot[i])
1724 			atmci_cleanup_slot(host->slot[i], i);
1725 	}
1726 
1727 	clk_enable(host->mck);
1728 	mci_writel(host, IDR, ~0UL);
1729 	mci_writel(host, CR, MCI_CR_MCIDIS);
1730 	mci_readl(host, SR);
1731 	clk_disable(host->mck);
1732 
1733 #ifdef CONFIG_MMC_ATMELMCI_DMA
1734 	if (host->dma.client.slave)
1735 		dma_async_client_unregister(&host->dma.client);
1736 #endif
1737 
1738 	free_irq(platform_get_irq(pdev, 0), host);
1739 	iounmap(host->regs);
1740 
1741 	clk_put(host->mck);
1742 	kfree(host);
1743 
1744 	return 0;
1745 }
1746 
1747 static struct platform_driver atmci_driver = {
1748 	.remove		= __exit_p(atmci_remove),
1749 	.driver		= {
1750 		.name		= "atmel_mci",
1751 	},
1752 };
1753 
1754 static int __init atmci_init(void)
1755 {
1756 	return platform_driver_probe(&atmci_driver, atmci_probe);
1757 }
1758 
1759 static void __exit atmci_exit(void)
1760 {
1761 	platform_driver_unregister(&atmci_driver);
1762 }
1763 
1764 module_init(atmci_init);
1765 module_exit(atmci_exit);
1766 
1767 MODULE_DESCRIPTION("Atmel Multimedia Card Interface driver");
1768 MODULE_AUTHOR("Haavard Skinnemoen <haavard.skinnemoen@atmel.com>");
1769 MODULE_LICENSE("GPL v2");
1770