mmc.c 13.3 KB
Newer Older
P
Pierre Ossman 已提交
1
/*
P
Pierre Ossman 已提交
2
 *  linux/drivers/mmc/core/mmc.c
P
Pierre Ossman 已提交
3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
 *
 *  Copyright (C) 2003-2004 Russell King, All Rights Reserved.
 *  Copyright (C) 2005-2007 Pierre Ossman, All Rights Reserved.
 *  MMCv4 support Copyright (C) 2006 Philip Langdale, All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/err.h>

#include <linux/mmc/host.h>
#include <linux/mmc/card.h>
#include <linux/mmc/mmc.h>

#include "core.h"
#include "sysfs.h"
P
Pierre Ossman 已提交
21
#include "bus.h"
P
Pierre Ossman 已提交
22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59
#include "mmc_ops.h"

static const unsigned int tran_exp[] = {
	10000,		100000,		1000000,	10000000,
	0,		0,		0,		0
};

static const unsigned char tran_mant[] = {
	0,	10,	12,	13,	15,	20,	25,	30,
	35,	40,	45,	50,	55,	60,	70,	80,
};

static const unsigned int tacc_exp[] = {
	1,	10,	100,	1000,	10000,	100000,	1000000, 10000000,
};

static const unsigned int tacc_mant[] = {
	0,	10,	12,	13,	15,	20,	25,	30,
	35,	40,	45,	50,	55,	60,	70,	80,
};

#define UNSTUFF_BITS(resp,start,size)					\
	({								\
		const int __size = size;				\
		const u32 __mask = (__size < 32 ? 1 << __size : 0) - 1;	\
		const int __off = 3 - ((start) / 32);			\
		const int __shft = (start) & 31;			\
		u32 __res;						\
									\
		__res = resp[__off] >> __shft;				\
		if (__size + __shft > 32)				\
			__res |= resp[__off-1] << ((32 - __shft) % 32);	\
		__res & __mask;						\
	})

/*
 * Given the decoded CSD structure, decode the raw CID to our CID structure.
 */
P
Pierre Ossman 已提交
60
static int mmc_decode_cid(struct mmc_card *card)
P
Pierre Ossman 已提交
61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102
{
	u32 *resp = card->raw_cid;

	/*
	 * The selection of the format here is based upon published
	 * specs from sandisk and from what people have reported.
	 */
	switch (card->csd.mmca_vsn) {
	case 0: /* MMC v1.0 - v1.2 */
	case 1: /* MMC v1.4 */
		card->cid.manfid	= UNSTUFF_BITS(resp, 104, 24);
		card->cid.prod_name[0]	= UNSTUFF_BITS(resp, 96, 8);
		card->cid.prod_name[1]	= UNSTUFF_BITS(resp, 88, 8);
		card->cid.prod_name[2]	= UNSTUFF_BITS(resp, 80, 8);
		card->cid.prod_name[3]	= UNSTUFF_BITS(resp, 72, 8);
		card->cid.prod_name[4]	= UNSTUFF_BITS(resp, 64, 8);
		card->cid.prod_name[5]	= UNSTUFF_BITS(resp, 56, 8);
		card->cid.prod_name[6]	= UNSTUFF_BITS(resp, 48, 8);
		card->cid.hwrev		= UNSTUFF_BITS(resp, 44, 4);
		card->cid.fwrev		= UNSTUFF_BITS(resp, 40, 4);
		card->cid.serial	= UNSTUFF_BITS(resp, 16, 24);
		card->cid.month		= UNSTUFF_BITS(resp, 12, 4);
		card->cid.year		= UNSTUFF_BITS(resp, 8, 4) + 1997;
		break;

	case 2: /* MMC v2.0 - v2.2 */
	case 3: /* MMC v3.1 - v3.3 */
	case 4: /* MMC v4 */
		card->cid.manfid	= UNSTUFF_BITS(resp, 120, 8);
		card->cid.oemid		= UNSTUFF_BITS(resp, 104, 16);
		card->cid.prod_name[0]	= UNSTUFF_BITS(resp, 96, 8);
		card->cid.prod_name[1]	= UNSTUFF_BITS(resp, 88, 8);
		card->cid.prod_name[2]	= UNSTUFF_BITS(resp, 80, 8);
		card->cid.prod_name[3]	= UNSTUFF_BITS(resp, 72, 8);
		card->cid.prod_name[4]	= UNSTUFF_BITS(resp, 64, 8);
		card->cid.prod_name[5]	= UNSTUFF_BITS(resp, 56, 8);
		card->cid.serial	= UNSTUFF_BITS(resp, 16, 32);
		card->cid.month		= UNSTUFF_BITS(resp, 12, 4);
		card->cid.year		= UNSTUFF_BITS(resp, 8, 4) + 1997;
		break;

	default:
P
Pierre Ossman 已提交
103
		printk(KERN_ERR "%s: card has unknown MMCA version %d\n",
P
Pierre Ossman 已提交
104
			mmc_hostname(card->host), card->csd.mmca_vsn);
P
Pierre Ossman 已提交
105
		return -EINVAL;
P
Pierre Ossman 已提交
106
	}
P
Pierre Ossman 已提交
107 108

	return 0;
P
Pierre Ossman 已提交
109 110 111 112 113
}

/*
 * Given a 128-bit response, decode to our card CSD structure.
 */
P
Pierre Ossman 已提交
114
static int mmc_decode_csd(struct mmc_card *card)
P
Pierre Ossman 已提交
115 116 117 118 119 120 121 122 123 124 125
{
	struct mmc_csd *csd = &card->csd;
	unsigned int e, m, csd_struct;
	u32 *resp = card->raw_csd;

	/*
	 * We only understand CSD structure v1.1 and v1.2.
	 * v1.2 has extra information in bits 15, 11 and 10.
	 */
	csd_struct = UNSTUFF_BITS(resp, 126, 2);
	if (csd_struct != 1 && csd_struct != 2) {
P
Pierre Ossman 已提交
126
		printk(KERN_ERR "%s: unrecognised CSD structure version %d\n",
P
Pierre Ossman 已提交
127
			mmc_hostname(card->host), csd_struct);
P
Pierre Ossman 已提交
128
		return -EINVAL;
P
Pierre Ossman 已提交
129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152
	}

	csd->mmca_vsn	 = UNSTUFF_BITS(resp, 122, 4);
	m = UNSTUFF_BITS(resp, 115, 4);
	e = UNSTUFF_BITS(resp, 112, 3);
	csd->tacc_ns	 = (tacc_exp[e] * tacc_mant[m] + 9) / 10;
	csd->tacc_clks	 = UNSTUFF_BITS(resp, 104, 8) * 100;

	m = UNSTUFF_BITS(resp, 99, 4);
	e = UNSTUFF_BITS(resp, 96, 3);
	csd->max_dtr	  = tran_exp[e] * tran_mant[m];
	csd->cmdclass	  = UNSTUFF_BITS(resp, 84, 12);

	e = UNSTUFF_BITS(resp, 47, 3);
	m = UNSTUFF_BITS(resp, 62, 12);
	csd->capacity	  = (1 + m) << (e + 2);

	csd->read_blkbits = UNSTUFF_BITS(resp, 80, 4);
	csd->read_partial = UNSTUFF_BITS(resp, 79, 1);
	csd->write_misalign = UNSTUFF_BITS(resp, 78, 1);
	csd->read_misalign = UNSTUFF_BITS(resp, 77, 1);
	csd->r2w_factor = UNSTUFF_BITS(resp, 26, 3);
	csd->write_blkbits = UNSTUFF_BITS(resp, 22, 4);
	csd->write_partial = UNSTUFF_BITS(resp, 21, 1);
P
Pierre Ossman 已提交
153 154

	return 0;
P
Pierre Ossman 已提交
155 156 157
}

/*
158
 * Read and decode extended CSD.
P
Pierre Ossman 已提交
159
 */
160
static int mmc_read_ext_csd(struct mmc_card *card)
P
Pierre Ossman 已提交
161 162 163
{
	int err;
	u8 *ext_csd;
P
Pierre Ossman 已提交
164
	unsigned int ext_csd_struct;
P
Pierre Ossman 已提交
165 166 167

	BUG_ON(!card);

P
Pierre Ossman 已提交
168
	err = -EIO;
P
Pierre Ossman 已提交
169 170

	if (card->csd.mmca_vsn < CSD_SPEC_VER_4)
P
Pierre Ossman 已提交
171
		return 0;
P
Pierre Ossman 已提交
172 173 174 175 176 177 178 179

	/*
	 * As the ext_csd is so large and mostly unused, we don't store the
	 * raw block in mmc_card.
	 */
	ext_csd = kmalloc(512, GFP_KERNEL);
	if (!ext_csd) {
		printk(KERN_ERR "%s: could not allocate a buffer to "
P
Pierre Ossman 已提交
180
			"receive the ext_csd.\n", mmc_hostname(card->host));
P
Pierre Ossman 已提交
181
		return -ENOMEM;
P
Pierre Ossman 已提交
182 183 184
	}

	err = mmc_send_ext_csd(card, ext_csd);
P
Pierre Ossman 已提交
185
	if (err) {
P
Pierre Ossman 已提交
186 187 188 189 190 191 192
		/*
		 * We all hosts that cannot perform the command
		 * to fail more gracefully
		 */
		if (err != -EINVAL)
			goto out;

P
Pierre Ossman 已提交
193 194 195 196 197 198 199 200 201 202 203 204 205 206
		/*
		 * High capacity cards should have this "magic" size
		 * stored in their CSD.
		 */
		if (card->csd.capacity == (4096 * 512)) {
			printk(KERN_ERR "%s: unable to read EXT_CSD "
				"on a possible high capacity card. "
				"Card will be ignored.\n",
				mmc_hostname(card->host));
		} else {
			printk(KERN_WARNING "%s: unable to read "
				"EXT_CSD, performance might "
				"suffer.\n",
				mmc_hostname(card->host));
P
Pierre Ossman 已提交
207
			err = 0;
P
Pierre Ossman 已提交
208
		}
P
Pierre Ossman 已提交
209

P
Pierre Ossman 已提交
210 211 212
		goto out;
	}

P
Pierre Ossman 已提交
213 214
	ext_csd_struct = ext_csd[EXT_CSD_REV];
	if (ext_csd_struct > 2) {
P
Pierre Ossman 已提交
215 216 217
		printk(KERN_ERR "%s: unrecognised EXT_CSD structure "
			"version %d\n", mmc_hostname(card->host),
			ext_csd_struct);
P
Pierre Ossman 已提交
218 219 220 221 222 223 224 225 226 227 228 229
		return -EINVAL;
	}

	if (ext_csd_struct >= 2) {
		card->ext_csd.sectors =
			ext_csd[EXT_CSD_SEC_CNT + 0] << 0 |
			ext_csd[EXT_CSD_SEC_CNT + 1] << 8 |
			ext_csd[EXT_CSD_SEC_CNT + 2] << 16 |
			ext_csd[EXT_CSD_SEC_CNT + 3] << 24;
		if (card->ext_csd.sectors)
			mmc_card_set_blockaddr(card);
	}
P
Pierre Ossman 已提交
230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252

	switch (ext_csd[EXT_CSD_CARD_TYPE]) {
	case EXT_CSD_CARD_TYPE_52 | EXT_CSD_CARD_TYPE_26:
		card->ext_csd.hs_max_dtr = 52000000;
		break;
	case EXT_CSD_CARD_TYPE_26:
		card->ext_csd.hs_max_dtr = 26000000;
		break;
	default:
		/* MMC v4 spec says this cannot happen */
		printk(KERN_WARNING "%s: card is mmc v4 but doesn't "
			"support any high-speed modes.\n",
			mmc_hostname(card->host));
		goto out;
	}

out:
	kfree(ext_csd);

	return err;
}

/*
253 254 255 256
 * Handle the detection and initialisation of a card.
 *
 * In the case of a resume, "curcard" will contain the card
 * we're trying to reinitialise.
P
Pierre Ossman 已提交
257
 */
258
static int mmc_init_card(struct mmc_host *host, u32 ocr,
259
	struct mmc_card *oldcard)
P
Pierre Ossman 已提交
260 261 262 263 264 265 266
{
	struct mmc_card *card;
	int err;
	u32 cid[4];
	unsigned int max_dtr;

	BUG_ON(!host);
P
Pierre Ossman 已提交
267
	WARN_ON(!host->claimed);
P
Pierre Ossman 已提交
268 269 270 271 272 273 274 275 276 277

	/*
	 * Since we're changing the OCR value, we seem to
	 * need to tell some cards to go back to the idle
	 * state.  We wait 1ms to give cards time to
	 * respond.
	 */
	mmc_go_idle(host);

	/* The extra bit indicates that we support high capacity */
278
	err = mmc_send_op_cond(host, ocr | (1 << 30), NULL);
P
Pierre Ossman 已提交
279
	if (err)
280
		goto err;
P
Pierre Ossman 已提交
281 282 283 284 285

	/*
	 * Fetch CID from card.
	 */
	err = mmc_all_send_cid(host, cid);
P
Pierre Ossman 已提交
286
	if (err)
P
Pierre Ossman 已提交
287 288
		goto err;

289
	if (oldcard) {
P
Pierre Ossman 已提交
290 291
		if (memcmp(cid, oldcard->raw_cid, sizeof(cid)) != 0) {
			err = -ENOENT;
292
			goto err;
P
Pierre Ossman 已提交
293
		}
294 295 296 297 298 299 300

		card = oldcard;
	} else {
		/*
		 * Allocate card structure.
		 */
		card = mmc_alloc_card(host);
P
Pierre Ossman 已提交
301 302
		if (IS_ERR(card)) {
			err = PTR_ERR(card);
303
			goto err;
P
Pierre Ossman 已提交
304
		}
P
Pierre Ossman 已提交
305

306 307 308 309
		card->type = MMC_TYPE_MMC;
		card->rca = 1;
		memcpy(card->raw_cid, cid, sizeof(card->raw_cid));
	}
P
Pierre Ossman 已提交
310 311 312 313 314

	/*
	 * Set card RCA.
	 */
	err = mmc_set_relative_addr(card);
P
Pierre Ossman 已提交
315
	if (err)
P
Pierre Ossman 已提交
316 317 318 319
		goto free_card;

	mmc_set_bus_mode(host, MMC_BUSMODE_PUSHPULL);

320 321 322 323 324
	if (!oldcard) {
		/*
		 * Fetch CSD from card.
		 */
		err = mmc_send_csd(card, card->raw_csd);
P
Pierre Ossman 已提交
325
		if (err)
326
			goto free_card;
P
Pierre Ossman 已提交
327

P
Pierre Ossman 已提交
328
		err = mmc_decode_csd(card);
P
Pierre Ossman 已提交
329
		if (err)
P
Pierre Ossman 已提交
330 331
			goto free_card;
		err = mmc_decode_cid(card);
P
Pierre Ossman 已提交
332
		if (err)
P
Pierre Ossman 已提交
333
			goto free_card;
334
	}
P
Pierre Ossman 已提交
335 336

	/*
337
	 * Select card, as all following commands rely on that.
P
Pierre Ossman 已提交
338 339
	 */
	err = mmc_select_card(card);
P
Pierre Ossman 已提交
340
	if (err)
P
Pierre Ossman 已提交
341 342
		goto free_card;

343 344 345 346 347
	if (!oldcard) {
		/*
		 * Fetch and process extened CSD.
		 */
		err = mmc_read_ext_csd(card);
P
Pierre Ossman 已提交
348
		if (err)
349 350
			goto free_card;
	}
P
Pierre Ossman 已提交
351

352 353 354 355 356 357 358
	/*
	 * Activate high speed (if supported)
	 */
	if ((card->ext_csd.hs_max_dtr != 0) &&
		(host->caps & MMC_CAP_MMC_HIGHSPEED)) {
		err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
			EXT_CSD_HS_TIMING, 1);
P
Pierre Ossman 已提交
359
		if (err)
360 361 362 363 364 365 366
			goto free_card;

		mmc_card_set_highspeed(card);

		mmc_set_timing(card->host, MMC_TIMING_MMC_HS);
	}

P
Pierre Ossman 已提交
367 368 369 370 371 372 373 374 375 376 377 378 379 380
	/*
	 * Compute bus speed.
	 */
	max_dtr = (unsigned int)-1;

	if (mmc_card_highspeed(card)) {
		if (max_dtr > card->ext_csd.hs_max_dtr)
			max_dtr = card->ext_csd.hs_max_dtr;
	} else if (max_dtr > card->csd.max_dtr) {
		max_dtr = card->csd.max_dtr;
	}

	mmc_set_clock(host, max_dtr);

381 382 383 384 385 386 387
	/*
	 * Activate wide bus (if supported).
	 */
	if ((card->csd.mmca_vsn >= CSD_SPEC_VER_4) &&
		(host->caps & MMC_CAP_4_BIT_DATA)) {
		err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
			EXT_CSD_BUS_WIDTH, EXT_CSD_BUS_WIDTH_4);
P
Pierre Ossman 已提交
388
		if (err)
389 390 391 392 393
			goto free_card;

		mmc_set_bus_width(card->host, MMC_BUS_WIDTH_4);
	}

394 395 396
	if (!oldcard)
		host->card = card;

P
Pierre Ossman 已提交
397
	return 0;
398 399 400 401 402 403

free_card:
	if (!oldcard)
		mmc_remove_card(card);
err:

P
Pierre Ossman 已提交
404
	return err;
405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437
}

/*
 * Host is being removed. Free up the current card.
 */
static void mmc_remove(struct mmc_host *host)
{
	BUG_ON(!host);
	BUG_ON(!host->card);

	mmc_remove_card(host->card);
	host->card = NULL;
}

/*
 * Card detection callback from host.
 */
static void mmc_detect(struct mmc_host *host)
{
	int err;

	BUG_ON(!host);
	BUG_ON(!host->card);

	mmc_claim_host(host);

	/*
	 * Just check if our card has been removed.
	 */
	err = mmc_send_status(host->card, NULL);

	mmc_release_host(host);

P
Pierre Ossman 已提交
438
	if (err) {
P
Pierre Ossman 已提交
439
		mmc_remove(host);
440 441 442 443 444 445 446

		mmc_claim_host(host);
		mmc_detach_bus(host);
		mmc_release_host(host);
	}
}

P
Pierre Ossman 已提交
447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493
MMC_ATTR_FN(cid, "%08x%08x%08x%08x\n", card->raw_cid[0], card->raw_cid[1],
	card->raw_cid[2], card->raw_cid[3]);
MMC_ATTR_FN(csd, "%08x%08x%08x%08x\n", card->raw_csd[0], card->raw_csd[1],
	card->raw_csd[2], card->raw_csd[3]);
MMC_ATTR_FN(date, "%02d/%04d\n", card->cid.month, card->cid.year);
MMC_ATTR_FN(fwrev, "0x%x\n", card->cid.fwrev);
MMC_ATTR_FN(hwrev, "0x%x\n", card->cid.hwrev);
MMC_ATTR_FN(manfid, "0x%06x\n", card->cid.manfid);
MMC_ATTR_FN(name, "%s\n", card->cid.prod_name);
MMC_ATTR_FN(oemid, "0x%04x\n", card->cid.oemid);
MMC_ATTR_FN(serial, "0x%08x\n", card->cid.serial);

static struct device_attribute mmc_dev_attrs[] = {
	MMC_ATTR_RO(cid),
	MMC_ATTR_RO(csd),
	MMC_ATTR_RO(date),
	MMC_ATTR_RO(fwrev),
	MMC_ATTR_RO(hwrev),
	MMC_ATTR_RO(manfid),
	MMC_ATTR_RO(name),
	MMC_ATTR_RO(oemid),
	MMC_ATTR_RO(serial),
	__ATTR_NULL,
};

/*
 * Adds sysfs entries as relevant.
 */
static int mmc_sysfs_add(struct mmc_host *host, struct mmc_card *card)
{
	int ret;

	ret = mmc_add_attrs(card, mmc_dev_attrs);
	if (ret < 0)
		return ret;

	return 0;
}

/*
 * Removes the sysfs entries added by mmc_sysfs_add().
 */
static void mmc_sysfs_remove(struct mmc_host *host, struct mmc_card *card)
{
	mmc_remove_attrs(card, mmc_dev_attrs);
}

494 495 496 497 498 499 500 501 502
#ifdef CONFIG_MMC_UNSAFE_RESUME

/*
 * Suspend callback from host.
 */
static void mmc_suspend(struct mmc_host *host)
{
	BUG_ON(!host);
	BUG_ON(!host->card);
P
Pierre Ossman 已提交
503

504 505 506
	mmc_claim_host(host);
	mmc_deselect_cards(host);
	host->card->state &= ~MMC_STATE_HIGHSPEED;
P
Pierre Ossman 已提交
507
	mmc_release_host(host);
508
}
P
Pierre Ossman 已提交
509

510 511 512 513 514 515 516 517 518 519 520 521 522 523
/*
 * Resume callback from host.
 *
 * This function tries to determine if the same card is still present
 * and, if so, restore all state to it.
 */
static void mmc_resume(struct mmc_host *host)
{
	int err;

	BUG_ON(!host);
	BUG_ON(!host->card);

	mmc_claim_host(host);
524
	err = mmc_init_card(host, host->ocr, host->card);
525 526
	mmc_release_host(host);

P
Pierre Ossman 已提交
527
	if (err) {
P
Pierre Ossman 已提交
528
		mmc_remove(host);
529 530

		mmc_claim_host(host);
531
		mmc_detach_bus(host);
532
		mmc_release_host(host);
533 534 535 536 537 538 539 540 541 542 543 544 545 546
	}

}

#else

#define mmc_suspend NULL
#define mmc_resume NULL

#endif

static const struct mmc_bus_ops mmc_ops = {
	.remove = mmc_remove,
	.detect = mmc_detect,
P
Pierre Ossman 已提交
547 548
	.sysfs_add = mmc_sysfs_add,
	.sysfs_remove = mmc_sysfs_remove,
549 550 551 552 553 554 555 556 557 558 559 560
	.suspend = mmc_suspend,
	.resume = mmc_resume,
};

/*
 * Starting point for MMC card init.
 */
int mmc_attach_mmc(struct mmc_host *host, u32 ocr)
{
	int err;

	BUG_ON(!host);
P
Pierre Ossman 已提交
561
	WARN_ON(!host->claimed);
562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580

	mmc_attach_bus(host, &mmc_ops);

	/*
	 * Sanity check the voltages that the card claims to
	 * support.
	 */
	if (ocr & 0x7F) {
		printk(KERN_WARNING "%s: card claims to support voltages "
		       "below the defined range. These will be ignored.\n",
		       mmc_hostname(host));
		ocr &= ~0x7F;
	}

	host->ocr = mmc_select_voltage(host, ocr);

	/*
	 * Can we support the voltage of the card?
	 */
581 582
	if (!host->ocr) {
		err = -EINVAL;
583
		goto err;
584
	}
585 586 587 588

	/*
	 * Detect and init the card.
	 */
589
	err = mmc_init_card(host, host->ocr, NULL);
P
Pierre Ossman 已提交
590
	if (err)
591 592 593 594
		goto err;

	mmc_release_host(host);

P
Pierre Ossman 已提交
595
	err = mmc_add_card(host->card);
P
Pierre Ossman 已提交
596
	if (err)
597
		goto remove_card;
P
Pierre Ossman 已提交
598 599 600

	return 0;

601
remove_card:
602
	mmc_remove_card(host->card);
P
Pierre Ossman 已提交
603
	host->card = NULL;
604
	mmc_claim_host(host);
P
Pierre Ossman 已提交
605 606 607 608
err:
	mmc_detach_bus(host);
	mmc_release_host(host);

609 610 611
	printk(KERN_ERR "%s: error %d whilst initialising MMC card\n",
		mmc_hostname(host), err);

P
Pierre Ossman 已提交
612
	return err;
P
Pierre Ossman 已提交
613 614
}