xref: /openbmc/linux/drivers/mtd/maps/vmu-flash.c (revision 588b48ca)
1 /* vmu-flash.c
2  * Driver for SEGA Dreamcast Visual Memory Unit
3  *
4  * Copyright (c) Adrian McMenamin 2002 - 2009
5  * Copyright (c) Paul Mundt 2001
6  *
7  * Licensed under version 2 of the
8  * GNU General Public Licence
9  */
10 #include <linux/init.h>
11 #include <linux/slab.h>
12 #include <linux/sched.h>
13 #include <linux/delay.h>
14 #include <linux/maple.h>
15 #include <linux/mtd/mtd.h>
16 #include <linux/mtd/map.h>
17 
18 struct vmu_cache {
19 	unsigned char *buffer;		/* Cache */
20 	unsigned int block;		/* Which block was cached */
21 	unsigned long jiffies_atc;	/* When was it cached? */
22 	int valid;
23 };
24 
25 struct mdev_part {
26 	struct maple_device *mdev;
27 	int partition;
28 };
29 
30 struct vmupart {
31 	u16 user_blocks;
32 	u16 root_block;
33 	u16 numblocks;
34 	char *name;
35 	struct vmu_cache *pcache;
36 };
37 
38 struct memcard {
39 	u16 tempA;
40 	u16 tempB;
41 	u32 partitions;
42 	u32 blocklen;
43 	u32 writecnt;
44 	u32 readcnt;
45 	u32 removeable;
46 	int partition;
47 	int read;
48 	unsigned char *blockread;
49 	struct vmupart *parts;
50 	struct mtd_info *mtd;
51 };
52 
53 struct vmu_block {
54 	unsigned int num; /* block number */
55 	unsigned int ofs; /* block offset */
56 };
57 
58 static struct vmu_block *ofs_to_block(unsigned long src_ofs,
59 	struct mtd_info *mtd, int partition)
60 {
61 	struct vmu_block *vblock;
62 	struct maple_device *mdev;
63 	struct memcard *card;
64 	struct mdev_part *mpart;
65 	int num;
66 
67 	mpart = mtd->priv;
68 	mdev = mpart->mdev;
69 	card = maple_get_drvdata(mdev);
70 
71 	if (src_ofs >= card->parts[partition].numblocks * card->blocklen)
72 		goto failed;
73 
74 	num = src_ofs / card->blocklen;
75 	if (num > card->parts[partition].numblocks)
76 		goto failed;
77 
78 	vblock = kmalloc(sizeof(struct vmu_block), GFP_KERNEL);
79 	if (!vblock)
80 		goto failed;
81 
82 	vblock->num = num;
83 	vblock->ofs = src_ofs % card->blocklen;
84 	return vblock;
85 
86 failed:
87 	return NULL;
88 }
89 
90 /* Maple bus callback function for reads */
91 static void vmu_blockread(struct mapleq *mq)
92 {
93 	struct maple_device *mdev;
94 	struct memcard *card;
95 
96 	mdev = mq->dev;
97 	card = maple_get_drvdata(mdev);
98 	/* copy the read in data */
99 
100 	if (unlikely(!card->blockread))
101 		return;
102 
103 	memcpy(card->blockread, mq->recvbuf->buf + 12,
104 		card->blocklen/card->readcnt);
105 
106 }
107 
108 /* Interface with maple bus to read blocks
109  * caching the results so that other parts
110  * of the driver can access block reads */
111 static int maple_vmu_read_block(unsigned int num, unsigned char *buf,
112 	struct mtd_info *mtd)
113 {
114 	struct memcard *card;
115 	struct mdev_part *mpart;
116 	struct maple_device *mdev;
117 	int partition, error = 0, x, wait;
118 	unsigned char *blockread = NULL;
119 	struct vmu_cache *pcache;
120 	__be32 sendbuf;
121 
122 	mpart = mtd->priv;
123 	mdev = mpart->mdev;
124 	partition = mpart->partition;
125 	card = maple_get_drvdata(mdev);
126 	pcache = card->parts[partition].pcache;
127 	pcache->valid = 0;
128 
129 	/* prepare the cache for this block */
130 	if (!pcache->buffer) {
131 		pcache->buffer = kmalloc(card->blocklen, GFP_KERNEL);
132 		if (!pcache->buffer) {
133 			dev_err(&mdev->dev, "VMU at (%d, %d) - read fails due"
134 				" to lack of memory\n", mdev->port,
135 				mdev->unit);
136 			error = -ENOMEM;
137 			goto outB;
138 		}
139 	}
140 
141 	/*
142 	* Reads may be phased - again the hardware spec
143 	* supports this - though may not be any devices in
144 	* the wild that implement it, but we will here
145 	*/
146 	for (x = 0; x < card->readcnt; x++) {
147 		sendbuf = cpu_to_be32(partition << 24 | x << 16 | num);
148 
149 		if (atomic_read(&mdev->busy) == 1) {
150 			wait_event_interruptible_timeout(mdev->maple_wait,
151 				atomic_read(&mdev->busy) == 0, HZ);
152 			if (atomic_read(&mdev->busy) == 1) {
153 				dev_notice(&mdev->dev, "VMU at (%d, %d)"
154 					" is busy\n", mdev->port, mdev->unit);
155 				error = -EAGAIN;
156 				goto outB;
157 			}
158 		}
159 
160 		atomic_set(&mdev->busy, 1);
161 		blockread = kmalloc(card->blocklen/card->readcnt, GFP_KERNEL);
162 		if (!blockread) {
163 			error = -ENOMEM;
164 			atomic_set(&mdev->busy, 0);
165 			goto outB;
166 		}
167 		card->blockread = blockread;
168 
169 		maple_getcond_callback(mdev, vmu_blockread, 0,
170 			MAPLE_FUNC_MEMCARD);
171 		error = maple_add_packet(mdev, MAPLE_FUNC_MEMCARD,
172 				MAPLE_COMMAND_BREAD, 2, &sendbuf);
173 		/* Very long timeouts seem to be needed when box is stressed */
174 		wait = wait_event_interruptible_timeout(mdev->maple_wait,
175 			(atomic_read(&mdev->busy) == 0 ||
176 			atomic_read(&mdev->busy) == 2), HZ * 3);
177 		/*
178 		* MTD layer does not handle hotplugging well
179 		* so have to return errors when VMU is unplugged
180 		* in the middle of a read (busy == 2)
181 		*/
182 		if (error || atomic_read(&mdev->busy) == 2) {
183 			if (atomic_read(&mdev->busy) == 2)
184 				error = -ENXIO;
185 			atomic_set(&mdev->busy, 0);
186 			card->blockread = NULL;
187 			goto outA;
188 		}
189 		if (wait == 0 || wait == -ERESTARTSYS) {
190 			card->blockread = NULL;
191 			atomic_set(&mdev->busy, 0);
192 			error = -EIO;
193 			list_del_init(&(mdev->mq->list));
194 			kfree(mdev->mq->sendbuf);
195 			mdev->mq->sendbuf = NULL;
196 			if (wait == -ERESTARTSYS) {
197 				dev_warn(&mdev->dev, "VMU read on (%d, %d)"
198 					" interrupted on block 0x%X\n",
199 					mdev->port, mdev->unit, num);
200 			} else
201 				dev_notice(&mdev->dev, "VMU read on (%d, %d)"
202 					" timed out on block 0x%X\n",
203 					mdev->port, mdev->unit, num);
204 			goto outA;
205 		}
206 
207 		memcpy(buf + (card->blocklen/card->readcnt) * x, blockread,
208 			card->blocklen/card->readcnt);
209 
210 		memcpy(pcache->buffer + (card->blocklen/card->readcnt) * x,
211 			card->blockread, card->blocklen/card->readcnt);
212 		card->blockread = NULL;
213 		pcache->block = num;
214 		pcache->jiffies_atc = jiffies;
215 		pcache->valid = 1;
216 		kfree(blockread);
217 	}
218 
219 	return error;
220 
221 outA:
222 	kfree(blockread);
223 outB:
224 	return error;
225 }
226 
227 /* communicate with maple bus for phased writing */
228 static int maple_vmu_write_block(unsigned int num, const unsigned char *buf,
229 	struct mtd_info *mtd)
230 {
231 	struct memcard *card;
232 	struct mdev_part *mpart;
233 	struct maple_device *mdev;
234 	int partition, error, locking, x, phaselen, wait;
235 	__be32 *sendbuf;
236 
237 	mpart = mtd->priv;
238 	mdev = mpart->mdev;
239 	partition = mpart->partition;
240 	card = maple_get_drvdata(mdev);
241 
242 	phaselen = card->blocklen/card->writecnt;
243 
244 	sendbuf = kmalloc(phaselen + 4, GFP_KERNEL);
245 	if (!sendbuf) {
246 		error = -ENOMEM;
247 		goto fail_nosendbuf;
248 	}
249 	for (x = 0; x < card->writecnt; x++) {
250 		sendbuf[0] = cpu_to_be32(partition << 24 | x << 16 | num);
251 		memcpy(&sendbuf[1], buf + phaselen * x, phaselen);
252 		/* wait until the device is not busy doing something else
253 		* or 1 second - which ever is longer */
254 		if (atomic_read(&mdev->busy) == 1) {
255 			wait_event_interruptible_timeout(mdev->maple_wait,
256 				atomic_read(&mdev->busy) == 0, HZ);
257 			if (atomic_read(&mdev->busy) == 1) {
258 				error = -EBUSY;
259 				dev_notice(&mdev->dev, "VMU write at (%d, %d)"
260 					"failed - device is busy\n",
261 					mdev->port, mdev->unit);
262 				goto fail_nolock;
263 			}
264 		}
265 		atomic_set(&mdev->busy, 1);
266 
267 		locking = maple_add_packet(mdev, MAPLE_FUNC_MEMCARD,
268 			MAPLE_COMMAND_BWRITE, phaselen / 4 + 2, sendbuf);
269 		wait = wait_event_interruptible_timeout(mdev->maple_wait,
270 			atomic_read(&mdev->busy) == 0, HZ/10);
271 		if (locking) {
272 			error = -EIO;
273 			atomic_set(&mdev->busy, 0);
274 			goto fail_nolock;
275 		}
276 		if (atomic_read(&mdev->busy) == 2) {
277 			atomic_set(&mdev->busy, 0);
278 		} else if (wait == 0 || wait == -ERESTARTSYS) {
279 			error = -EIO;
280 			dev_warn(&mdev->dev, "Write at (%d, %d) of block"
281 				" 0x%X at phase %d failed: could not"
282 				" communicate with VMU", mdev->port,
283 				mdev->unit, num, x);
284 			atomic_set(&mdev->busy, 0);
285 			kfree(mdev->mq->sendbuf);
286 			mdev->mq->sendbuf = NULL;
287 			list_del_init(&(mdev->mq->list));
288 			goto fail_nolock;
289 		}
290 	}
291 	kfree(sendbuf);
292 
293 	return card->blocklen;
294 
295 fail_nolock:
296 	kfree(sendbuf);
297 fail_nosendbuf:
298 	dev_err(&mdev->dev, "VMU (%d, %d): write failed\n", mdev->port,
299 		mdev->unit);
300 	return error;
301 }
302 
303 /* mtd function to simulate reading byte by byte */
304 static unsigned char vmu_flash_read_char(unsigned long ofs, int *retval,
305 	struct mtd_info *mtd)
306 {
307 	struct vmu_block *vblock;
308 	struct memcard *card;
309 	struct mdev_part *mpart;
310 	struct maple_device *mdev;
311 	unsigned char *buf, ret;
312 	int partition, error;
313 
314 	mpart = mtd->priv;
315 	mdev = mpart->mdev;
316 	partition = mpart->partition;
317 	card = maple_get_drvdata(mdev);
318 	*retval =  0;
319 
320 	buf = kmalloc(card->blocklen, GFP_KERNEL);
321 	if (!buf) {
322 		*retval = 1;
323 		ret = -ENOMEM;
324 		goto finish;
325 	}
326 
327 	vblock = ofs_to_block(ofs, mtd, partition);
328 	if (!vblock) {
329 		*retval = 3;
330 		ret = -ENOMEM;
331 		goto out_buf;
332 	}
333 
334 	error = maple_vmu_read_block(vblock->num, buf, mtd);
335 	if (error) {
336 		ret = error;
337 		*retval = 2;
338 		goto out_vblock;
339 	}
340 
341 	ret = buf[vblock->ofs];
342 
343 out_vblock:
344 	kfree(vblock);
345 out_buf:
346 	kfree(buf);
347 finish:
348 	return ret;
349 }
350 
351 /* mtd higher order function to read flash */
352 static int vmu_flash_read(struct mtd_info *mtd, loff_t from, size_t len,
353 	size_t *retlen,  u_char *buf)
354 {
355 	struct maple_device *mdev;
356 	struct memcard *card;
357 	struct mdev_part *mpart;
358 	struct vmu_cache *pcache;
359 	struct vmu_block *vblock;
360 	int index = 0, retval, partition, leftover, numblocks;
361 	unsigned char cx;
362 
363 	mpart = mtd->priv;
364 	mdev = mpart->mdev;
365 	partition = mpart->partition;
366 	card = maple_get_drvdata(mdev);
367 
368 	numblocks = card->parts[partition].numblocks;
369 	if (from + len > numblocks * card->blocklen)
370 		len = numblocks * card->blocklen - from;
371 	if (len == 0)
372 		return -EIO;
373 	/* Have we cached this bit already? */
374 	pcache = card->parts[partition].pcache;
375 	do {
376 		vblock =  ofs_to_block(from + index, mtd, partition);
377 		if (!vblock)
378 			return -ENOMEM;
379 		/* Have we cached this and is the cache valid and timely? */
380 		if (pcache->valid &&
381 			time_before(jiffies, pcache->jiffies_atc + HZ) &&
382 			(pcache->block == vblock->num)) {
383 			/* we have cached it, so do necessary copying */
384 			leftover = card->blocklen - vblock->ofs;
385 			if (vblock->ofs + len - index < card->blocklen) {
386 				/* only a bit of this block to copy */
387 				memcpy(buf + index,
388 					pcache->buffer + vblock->ofs,
389 					len - index);
390 				index = len;
391 			} else {
392 				/* otherwise copy remainder of whole block */
393 				memcpy(buf + index, pcache->buffer +
394 					vblock->ofs, leftover);
395 				index += leftover;
396 			}
397 		} else {
398 			/*
399 			* Not cached so read one byte -
400 			* but cache the rest of the block
401 			*/
402 			cx = vmu_flash_read_char(from + index, &retval, mtd);
403 			if (retval) {
404 				*retlen = index;
405 				kfree(vblock);
406 				return cx;
407 			}
408 			memset(buf + index, cx, 1);
409 			index++;
410 		}
411 		kfree(vblock);
412 	} while (len > index);
413 	*retlen = index;
414 
415 	return 0;
416 }
417 
418 static int vmu_flash_write(struct mtd_info *mtd, loff_t to, size_t len,
419 	size_t *retlen, const u_char *buf)
420 {
421 	struct maple_device *mdev;
422 	struct memcard *card;
423 	struct mdev_part *mpart;
424 	int index = 0, partition, error = 0, numblocks;
425 	struct vmu_cache *pcache;
426 	struct vmu_block *vblock;
427 	unsigned char *buffer;
428 
429 	mpart = mtd->priv;
430 	mdev = mpart->mdev;
431 	partition = mpart->partition;
432 	card = maple_get_drvdata(mdev);
433 
434 	numblocks = card->parts[partition].numblocks;
435 	if (to + len > numblocks * card->blocklen)
436 		len = numblocks * card->blocklen - to;
437 	if (len == 0) {
438 		error = -EIO;
439 		goto failed;
440 	}
441 
442 	vblock = ofs_to_block(to, mtd, partition);
443 	if (!vblock) {
444 		error = -ENOMEM;
445 		goto failed;
446 	}
447 
448 	buffer = kmalloc(card->blocklen, GFP_KERNEL);
449 	if (!buffer) {
450 		error = -ENOMEM;
451 		goto fail_buffer;
452 	}
453 
454 	do {
455 		/* Read in the block we are to write to */
456 		error = maple_vmu_read_block(vblock->num, buffer, mtd);
457 		if (error)
458 			goto fail_io;
459 
460 		do {
461 			buffer[vblock->ofs] = buf[index];
462 			vblock->ofs++;
463 			index++;
464 			if (index >= len)
465 				break;
466 		} while (vblock->ofs < card->blocklen);
467 
468 		/* write out new buffer */
469 		error = maple_vmu_write_block(vblock->num, buffer, mtd);
470 		/* invalidate the cache */
471 		pcache = card->parts[partition].pcache;
472 		pcache->valid = 0;
473 
474 		if (error != card->blocklen)
475 			goto fail_io;
476 
477 		vblock->num++;
478 		vblock->ofs = 0;
479 	} while (len > index);
480 
481 	kfree(buffer);
482 	*retlen = index;
483 	kfree(vblock);
484 	return 0;
485 
486 fail_io:
487 	kfree(buffer);
488 fail_buffer:
489 	kfree(vblock);
490 failed:
491 	dev_err(&mdev->dev, "VMU write failing with error %d\n", error);
492 	return error;
493 }
494 
495 static void vmu_flash_sync(struct mtd_info *mtd)
496 {
497 	/* Do nothing here */
498 }
499 
500 /* Maple bus callback function to recursively query hardware details */
501 static void vmu_queryblocks(struct mapleq *mq)
502 {
503 	struct maple_device *mdev;
504 	unsigned short *res;
505 	struct memcard *card;
506 	__be32 partnum;
507 	struct vmu_cache *pcache;
508 	struct mdev_part *mpart;
509 	struct mtd_info *mtd_cur;
510 	struct vmupart *part_cur;
511 	int error;
512 
513 	mdev = mq->dev;
514 	card = maple_get_drvdata(mdev);
515 	res = (unsigned short *) (mq->recvbuf->buf);
516 	card->tempA = res[12];
517 	card->tempB = res[6];
518 
519 	dev_info(&mdev->dev, "VMU device at partition %d has %d user "
520 		"blocks with a root block at %d\n", card->partition,
521 		card->tempA, card->tempB);
522 
523 	part_cur = &card->parts[card->partition];
524 	part_cur->user_blocks = card->tempA;
525 	part_cur->root_block = card->tempB;
526 	part_cur->numblocks = card->tempB + 1;
527 	part_cur->name = kmalloc(12, GFP_KERNEL);
528 	if (!part_cur->name)
529 		goto fail_name;
530 
531 	sprintf(part_cur->name, "vmu%d.%d.%d",
532 		mdev->port, mdev->unit, card->partition);
533 	mtd_cur = &card->mtd[card->partition];
534 	mtd_cur->name = part_cur->name;
535 	mtd_cur->type = 8;
536 	mtd_cur->flags = MTD_WRITEABLE|MTD_NO_ERASE;
537 	mtd_cur->size = part_cur->numblocks * card->blocklen;
538 	mtd_cur->erasesize = card->blocklen;
539 	mtd_cur->_write = vmu_flash_write;
540 	mtd_cur->_read = vmu_flash_read;
541 	mtd_cur->_sync = vmu_flash_sync;
542 	mtd_cur->writesize = card->blocklen;
543 
544 	mpart = kmalloc(sizeof(struct mdev_part), GFP_KERNEL);
545 	if (!mpart)
546 		goto fail_mpart;
547 
548 	mpart->mdev = mdev;
549 	mpart->partition = card->partition;
550 	mtd_cur->priv = mpart;
551 	mtd_cur->owner = THIS_MODULE;
552 
553 	pcache = kzalloc(sizeof(struct vmu_cache), GFP_KERNEL);
554 	if (!pcache)
555 		goto fail_cache_create;
556 	part_cur->pcache = pcache;
557 
558 	error = mtd_device_register(mtd_cur, NULL, 0);
559 	if (error)
560 		goto fail_mtd_register;
561 
562 	maple_getcond_callback(mdev, NULL, 0,
563 		MAPLE_FUNC_MEMCARD);
564 
565 	/*
566 	* Set up a recursive call to the (probably theoretical)
567 	* second or more partition
568 	*/
569 	if (++card->partition < card->partitions) {
570 		partnum = cpu_to_be32(card->partition << 24);
571 		maple_getcond_callback(mdev, vmu_queryblocks, 0,
572 			MAPLE_FUNC_MEMCARD);
573 		maple_add_packet(mdev, MAPLE_FUNC_MEMCARD,
574 			MAPLE_COMMAND_GETMINFO, 2, &partnum);
575 	}
576 	return;
577 
578 fail_mtd_register:
579 	dev_err(&mdev->dev, "Could not register maple device at (%d, %d)"
580 		"error is 0x%X\n", mdev->port, mdev->unit, error);
581 	for (error = 0; error <= card->partition; error++) {
582 		kfree(((card->parts)[error]).pcache);
583 		((card->parts)[error]).pcache = NULL;
584 	}
585 fail_cache_create:
586 fail_mpart:
587 	for (error = 0; error <= card->partition; error++) {
588 		kfree(((card->mtd)[error]).priv);
589 		((card->mtd)[error]).priv = NULL;
590 	}
591 	maple_getcond_callback(mdev, NULL, 0,
592 		MAPLE_FUNC_MEMCARD);
593 	kfree(part_cur->name);
594 fail_name:
595 	return;
596 }
597 
598 /* Handles very basic info about the flash, queries for details */
599 static int vmu_connect(struct maple_device *mdev)
600 {
601 	unsigned long test_flash_data, basic_flash_data;
602 	int c, error;
603 	struct memcard *card;
604 	u32 partnum = 0;
605 
606 	test_flash_data = be32_to_cpu(mdev->devinfo.function);
607 	/* Need to count how many bits are set - to find out which
608 	 * function_data element has details of the memory card
609 	 */
610 	c = hweight_long(test_flash_data);
611 
612 	basic_flash_data = be32_to_cpu(mdev->devinfo.function_data[c - 1]);
613 
614 	card = kmalloc(sizeof(struct memcard), GFP_KERNEL);
615 	if (!card) {
616 		error = -ENOMEM;
617 		goto fail_nomem;
618 	}
619 
620 	card->partitions = (basic_flash_data >> 24 & 0xFF) + 1;
621 	card->blocklen = ((basic_flash_data >> 16 & 0xFF) + 1) << 5;
622 	card->writecnt = basic_flash_data >> 12 & 0xF;
623 	card->readcnt = basic_flash_data >> 8 & 0xF;
624 	card->removeable = basic_flash_data >> 7 & 1;
625 
626 	card->partition = 0;
627 
628 	/*
629 	* Not sure there are actually any multi-partition devices in the
630 	* real world, but the hardware supports them, so, so will we
631 	*/
632 	card->parts = kmalloc(sizeof(struct vmupart) * card->partitions,
633 		GFP_KERNEL);
634 	if (!card->parts) {
635 		error = -ENOMEM;
636 		goto fail_partitions;
637 	}
638 
639 	card->mtd = kmalloc(sizeof(struct mtd_info) * card->partitions,
640 		GFP_KERNEL);
641 	if (!card->mtd) {
642 		error = -ENOMEM;
643 		goto fail_mtd_info;
644 	}
645 
646 	maple_set_drvdata(mdev, card);
647 
648 	/*
649 	* We want to trap meminfo not get cond
650 	* so set interval to zero, but rely on maple bus
651 	* driver to pass back the results of the meminfo
652 	*/
653 	maple_getcond_callback(mdev, vmu_queryblocks, 0,
654 		MAPLE_FUNC_MEMCARD);
655 
656 	/* Make sure we are clear to go */
657 	if (atomic_read(&mdev->busy) == 1) {
658 		wait_event_interruptible_timeout(mdev->maple_wait,
659 			atomic_read(&mdev->busy) == 0, HZ);
660 		if (atomic_read(&mdev->busy) == 1) {
661 			dev_notice(&mdev->dev, "VMU at (%d, %d) is busy\n",
662 				mdev->port, mdev->unit);
663 			error = -EAGAIN;
664 			goto fail_device_busy;
665 		}
666 	}
667 
668 	atomic_set(&mdev->busy, 1);
669 
670 	/*
671 	* Set up the minfo call: vmu_queryblocks will handle
672 	* the information passed back
673 	*/
674 	error = maple_add_packet(mdev, MAPLE_FUNC_MEMCARD,
675 		MAPLE_COMMAND_GETMINFO, 2, &partnum);
676 	if (error) {
677 		dev_err(&mdev->dev, "Could not lock VMU at (%d, %d)"
678 			" error is 0x%X\n", mdev->port, mdev->unit, error);
679 		goto fail_mtd_info;
680 	}
681 	return 0;
682 
683 fail_device_busy:
684 	kfree(card->mtd);
685 fail_mtd_info:
686 	kfree(card->parts);
687 fail_partitions:
688 	kfree(card);
689 fail_nomem:
690 	return error;
691 }
692 
693 static void vmu_disconnect(struct maple_device *mdev)
694 {
695 	struct memcard *card;
696 	struct mdev_part *mpart;
697 	int x;
698 
699 	mdev->callback = NULL;
700 	card = maple_get_drvdata(mdev);
701 	for (x = 0; x < card->partitions; x++) {
702 		mpart = ((card->mtd)[x]).priv;
703 		mpart->mdev = NULL;
704 		mtd_device_unregister(&((card->mtd)[x]));
705 		kfree(((card->parts)[x]).name);
706 	}
707 	kfree(card->parts);
708 	kfree(card->mtd);
709 	kfree(card);
710 }
711 
712 /* Callback to handle eccentricities of both mtd subsystem
713  * and general flakyness of Dreamcast VMUs
714  */
715 static int vmu_can_unload(struct maple_device *mdev)
716 {
717 	struct memcard *card;
718 	int x;
719 	struct mtd_info *mtd;
720 
721 	card = maple_get_drvdata(mdev);
722 	for (x = 0; x < card->partitions; x++) {
723 		mtd = &((card->mtd)[x]);
724 		if (mtd->usecount > 0)
725 			return 0;
726 	}
727 	return 1;
728 }
729 
730 #define ERRSTR "VMU at (%d, %d) file error -"
731 
732 static void vmu_file_error(struct maple_device *mdev, void *recvbuf)
733 {
734 	enum maple_file_errors error = ((int *)recvbuf)[1];
735 
736 	switch (error) {
737 
738 	case MAPLE_FILEERR_INVALID_PARTITION:
739 		dev_notice(&mdev->dev, ERRSTR " invalid partition number\n",
740 			mdev->port, mdev->unit);
741 		break;
742 
743 	case MAPLE_FILEERR_PHASE_ERROR:
744 		dev_notice(&mdev->dev, ERRSTR " phase error\n",
745 			mdev->port, mdev->unit);
746 		break;
747 
748 	case MAPLE_FILEERR_INVALID_BLOCK:
749 		dev_notice(&mdev->dev, ERRSTR " invalid block number\n",
750 			mdev->port, mdev->unit);
751 		break;
752 
753 	case MAPLE_FILEERR_WRITE_ERROR:
754 		dev_notice(&mdev->dev, ERRSTR " write error\n",
755 			mdev->port, mdev->unit);
756 		break;
757 
758 	case MAPLE_FILEERR_INVALID_WRITE_LENGTH:
759 		dev_notice(&mdev->dev, ERRSTR " invalid write length\n",
760 			mdev->port, mdev->unit);
761 		break;
762 
763 	case MAPLE_FILEERR_BAD_CRC:
764 		dev_notice(&mdev->dev, ERRSTR " bad CRC\n",
765 			mdev->port, mdev->unit);
766 		break;
767 
768 	default:
769 		dev_notice(&mdev->dev, ERRSTR " 0x%X\n",
770 			mdev->port, mdev->unit, error);
771 	}
772 }
773 
774 
775 static int probe_maple_vmu(struct device *dev)
776 {
777 	int error;
778 	struct maple_device *mdev = to_maple_dev(dev);
779 	struct maple_driver *mdrv = to_maple_driver(dev->driver);
780 
781 	mdev->can_unload = vmu_can_unload;
782 	mdev->fileerr_handler = vmu_file_error;
783 	mdev->driver = mdrv;
784 
785 	error = vmu_connect(mdev);
786 	if (error)
787 		return error;
788 
789 	return 0;
790 }
791 
792 static int remove_maple_vmu(struct device *dev)
793 {
794 	struct maple_device *mdev = to_maple_dev(dev);
795 
796 	vmu_disconnect(mdev);
797 	return 0;
798 }
799 
800 static struct maple_driver vmu_flash_driver = {
801 	.function =	MAPLE_FUNC_MEMCARD,
802 	.drv = {
803 		.name =		"Dreamcast_visual_memory",
804 		.probe =	probe_maple_vmu,
805 		.remove =	remove_maple_vmu,
806 	},
807 };
808 
809 static int __init vmu_flash_map_init(void)
810 {
811 	return maple_driver_register(&vmu_flash_driver);
812 }
813 
814 static void __exit vmu_flash_map_exit(void)
815 {
816 	maple_driver_unregister(&vmu_flash_driver);
817 }
818 
819 module_init(vmu_flash_map_init);
820 module_exit(vmu_flash_map_exit);
821 
822 MODULE_LICENSE("GPL");
823 MODULE_AUTHOR("Adrian McMenamin");
824 MODULE_DESCRIPTION("Flash mapping for Sega Dreamcast visual memory");
825