drivers/mmc/core/sd.c

   1 /*
   2  *  linux/drivers/mmc/core/sd.c
   3  *
   4  *  Copyright (C) 2003-2004 Russell King, All Rights Reserved.
   5  *  SD support Copyright (C) 2004 Ian Molton, All Rights Reserved.
   6  *  Copyright (C) 2005-2007 Pierre Ossman, All Rights Reserved.
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/err.h>
  14 #include <linux/slab.h>
  15
  16 #include <linux/mmc/host.h>
  17 #include <linux/mmc/card.h>
  18 #include <linux/mmc/mmc.h>
  19 #include <linux/mmc/sd.h>
  20
  21 #include "core.h"
  22 #include "bus.h"
  23 #include "mmc_ops.h"
  24 #include "sd_ops.h"
  25
  26 static const unsigned int tran_exp[] = {
  27         10000,          100000,         1000000,        10000000,
  28         0,              0,              0,              0
  29 };
  30
  31 static const unsigned char tran_mant[] = {
  32         0,      10,     12,     13,     15,     20,     25,     30,
  33         35,     40,     45,     50,     55,     60,     70,     80,
  34 };
  35
  36 static const unsigned int tacc_exp[] = {
  37         1,      10,     100,    1000,   10000,  100000, 1000000, 10000000,
  38 };
  39
  40 static const unsigned int tacc_mant[] = {
  41         0,      10,     12,     13,     15,     20,     25,     30,
  42         35,     40,     45,     50,     55,     60,     70,     80,
  43 };
  44
  45 #define UNSTUFF_BITS(resp,start,size)                                   \
  46         ({                                                              \
  47                 const int __size = size;                                \
  48                 const u32 __mask = (__size < 32 ? 1 << __size : 0) - 1; \
  49                 const int __off = 3 - ((start) / 32);                   \
  50                 const int __shft = (start) & 31;                        \
  51                 u32 __res;                                              \
  52                                                                         \
  53                 __res = resp[__off] >> __shft;                          \
  54                 if (__size + __shft > 32)                               \
  55                         __res |= resp[__off-1] << ((32 - __shft) % 32); \
  56                 __res & __mask;                                         \
  57         })
  58
  59 /*
  60  * Given the decoded CSD structure, decode the raw CID to our CID structure.
  61  */
  62 static void mmc_decode_cid(struct mmc_card *card)
  63 {
  64         u32 *resp = card->raw_cid;
  65
  66         memset(&card->cid, 0, sizeof(struct mmc_cid));
  67
  68         /*
  69          * SD doesn't currently have a version field so we will
  70          * have to assume we can parse this.
  71          */
  72         card->cid.manfid                = UNSTUFF_BITS(resp, 120, 8);
  73         card->cid.oemid                 = UNSTUFF_BITS(resp, 104, 16);
  74         card->cid.prod_name[0]          = UNSTUFF_BITS(resp, 96, 8);
  75         card->cid.prod_name[1]          = UNSTUFF_BITS(resp, 88, 8);
  76         card->cid.prod_name[2]          = UNSTUFF_BITS(resp, 80, 8);
  77         card->cid.prod_name[3]          = UNSTUFF_BITS(resp, 72, 8);
  78         card->cid.prod_name[4]          = UNSTUFF_BITS(resp, 64, 8);
  79         card->cid.hwrev                 = UNSTUFF_BITS(resp, 60, 4);
  80         card->cid.fwrev                 = UNSTUFF_BITS(resp, 56, 4);
  81         card->cid.serial                = UNSTUFF_BITS(resp, 24, 32);
  82         card->cid.year                  = UNSTUFF_BITS(resp, 12, 8);
  83         card->cid.month                 = UNSTUFF_BITS(resp, 8, 4);
  84
  85         card->cid.year += 2000; /* SD cards year offset */
  86 }
  87
  88 /*
  89  * Given a 128-bit response, decode to our card CSD structure.
  90  */
  91 static int mmc_decode_csd(struct mmc_card *card)
  92 {
  93         struct mmc_csd *csd = &card->csd;
  94         unsigned int e, m, csd_struct;
  95         u32 *resp = card->raw_csd;
  96
  97         csd_struct = UNSTUFF_BITS(resp, 126, 2);
  98
  99         switch (csd_struct) {
 100         case 0:
 101                 m = UNSTUFF_BITS(resp, 115, 4);
 102                 e = UNSTUFF_BITS(resp, 112, 3);
 103                 csd->tacc_ns     = (tacc_exp[e] * tacc_mant[m] + 9) / 10;
 104                 csd->tacc_clks   = UNSTUFF_BITS(resp, 104, 8) * 100;
 105
 106                 m = UNSTUFF_BITS(resp, 99, 4);
 107                 e = UNSTUFF_BITS(resp, 96, 3);
 108                 csd->max_dtr      = tran_exp[e] * tran_mant[m];
 109                 csd->cmdclass     = UNSTUFF_BITS(resp, 84, 12);
 110
 111                 e = UNSTUFF_BITS(resp, 47, 3);
 112                 m = UNSTUFF_BITS(resp, 62, 12);
 113                 csd->capacity     = (1 + m) << (e + 2);
 114
 115                 csd->read_blkbits = UNSTUFF_BITS(resp, 80, 4);
 116                 csd->read_partial = UNSTUFF_BITS(resp, 79, 1);
 117                 csd->write_misalign = UNSTUFF_BITS(resp, 78, 1);
 118                 csd->read_misalign = UNSTUFF_BITS(resp, 77, 1);
 119                 csd->r2w_factor = UNSTUFF_BITS(resp, 26, 3);
 120                 csd->write_blkbits = UNSTUFF_BITS(resp, 22, 4);
 121                 csd->write_partial = UNSTUFF_BITS(resp, 21, 1);
 122                 break;
 123         case 1:
 124                 /*
 125                  * This is a block-addressed SDHC card. Most
 126                  * interesting fields are unused and have fixed
 127                  * values. To avoid getting tripped by buggy cards,
 128                  * we assume those fixed values ourselves.
 129                  */
 130                 mmc_card_set_blockaddr(card);
 131
 132                 csd->tacc_ns     = 0; /* Unused */
 133                 csd->tacc_clks   = 0; /* Unused */
 134
 135                 m = UNSTUFF_BITS(resp, 99, 4);
 136                 e = UNSTUFF_BITS(resp, 96, 3);
 137                 csd->max_dtr      = tran_exp[e] * tran_mant[m];
 138                 csd->cmdclass     = UNSTUFF_BITS(resp, 84, 12);
 139
 140                 m = UNSTUFF_BITS(resp, 48, 22);
 141                 csd->capacity     = (1 + m) << 10;
 142
 143                 csd->read_blkbits = 9;
 144                 csd->read_partial = 0;
 145                 csd->write_misalign = 0;
 146                 csd->read_misalign = 0;
 147                 csd->r2w_factor = 4; /* Unused */
 148                 csd->write_blkbits = 9;
 149                 csd->write_partial = 0;
 150                 break;
 151         default:
 152                 printk(KERN_ERR "%s: unrecognised CSD structure version %d\n",
 153                         mmc_hostname(card->host), csd_struct);
 154                 return -EINVAL;
 155         }
 156
 157         return 0;
 158 }
 159
 160 /*
 161  * Given a 64-bit response, decode to our card SCR structure.
 162  */
 163 static int mmc_decode_scr(struct mmc_card *card)
 164 {
 165         struct sd_scr *scr = &card->scr;
 166         unsigned int scr_struct;
 167         u32 resp[4];
 168
 169         resp[3] = card->raw_scr[1];
 170         resp[2] = card->raw_scr[0];
 171
 172         scr_struct = UNSTUFF_BITS(resp, 60, 4);
 173         if (scr_struct != 0) {
 174                 printk(KERN_ERR "%s: unrecognised SCR structure version %d\n",
 175                         mmc_hostname(card->host), scr_struct);
 176                 return -EINVAL;
 177         }
 178
 179         scr->sda_vsn = UNSTUFF_BITS(resp, 56, 4);
 180         scr->bus_widths = UNSTUFF_BITS(resp, 48, 4);
 181
 182         return 0;
 183 }
 184
 185 /*
 186  * Fetches and decodes switch information
 187  */
 188 static int mmc_read_switch(struct mmc_card *card)
 189 {
 190         int err;
 191         u8 *status;
 192
 193         if (card->scr.sda_vsn < SCR_SPEC_VER_1)
 194                 return 0;
 195
 196         if (!(card->csd.cmdclass & CCC_SWITCH)) {
 197                 printk(KERN_WARNING "%s: card lacks mandatory switch "
 198                         "function, performance might suffer.\n",
 199                         mmc_hostname(card->host));
 200                 return 0;
 201         }
 202
 203         err = -EIO;
 204
 205         status = kmalloc(64, GFP_KERNEL);
 206         if (!status) {
 207                 printk(KERN_ERR "%s: could not allocate a buffer for "
 208                         "switch capabilities.\n", mmc_hostname(card->host));
 209                 return -ENOMEM;
 210         }
 211
 212         err = mmc_sd_switch(card, 0, 0, 1, status);
 213         if (err) {
 214                 /* If the host or the card can't do the switch,
 215                  * fail more gracefully. */
 216                 if ((err != -EINVAL)
 217                  && (err != -ENOSYS)
 218                  && (err != -EFAULT))
 219                         goto out;
 220
 221                 printk(KERN_WARNING "%s: problem reading switch "
 222                         "capabilities, performance might suffer.\n",
 223                         mmc_hostname(card->host));
 224                 err = 0;
 225
 226                 goto out;
 227         }
 228
 229         if (status[13] & 0x02)
 230                 card->sw_caps.hs_max_dtr = 50000000;
 231
 232 out:
 233         kfree(status);
 234
 235         return err;
 236 }
 237
 238 /*
 239  * Test if the card supports high-speed mode and, if so, switch to it.
 240  */
 241 static int mmc_switch_hs(struct mmc_card *card)
 242 {
 243         int err;
 244         u8 *status;
 245
 246         if (card->scr.sda_vsn < SCR_SPEC_VER_1)
 247                 return 0;
 248
 249         if (!(card->csd.cmdclass & CCC_SWITCH))
 250                 return 0;
 251
 252         if (!(card->host->caps & MMC_CAP_SD_HIGHSPEED))
 253                 return 0;
 254
 255         if (card->sw_caps.hs_max_dtr == 0)
 256                 return 0;
 257
 258         err = -EIO;
 259
 260         status = kmalloc(64, GFP_KERNEL);
 261         if (!status) {
 262                 printk(KERN_ERR "%s: could not allocate a buffer for "
 263                         "switch capabilities.\n", mmc_hostname(card->host));
 264                 return -ENOMEM;
 265         }
 266
 267         err = mmc_sd_switch(card, 1, 0, 1, status);
 268         if (err)
 269                 goto out;
 270
 271         if ((status[16] & 0xF) != 1) {
 272                 printk(KERN_WARNING "%s: Problem switching card "
 273                         "into high-speed mode!\n",
 274                         mmc_hostname(card->host));
 275         } else {
 276                 mmc_card_set_highspeed(card);
 277                 mmc_set_timing(card->host, MMC_TIMING_SD_HS);
 278         }
 279
 280 out:
 281         kfree(status);
 282
 283         return err;
 284 }
 285
 286 MMC_DEV_ATTR(cid, "%08x%08x%08x%08x\n", card->raw_cid[0], card->raw_cid[1],
 287         card->raw_cid[2], card->raw_cid[3]);
 288 MMC_DEV_ATTR(csd, "%08x%08x%08x%08x\n", card->raw_csd[0], card->raw_csd[1],
 289         card->raw_csd[2], card->raw_csd[3]);
 290 MMC_DEV_ATTR(scr, "%08x%08x\n", card->raw_scr[0], card->raw_scr[1]);
 291 MMC_DEV_ATTR(date, "%02d/%04d\n", card->cid.month, card->cid.year);
 292 MMC_DEV_ATTR(fwrev, "0x%x\n", card->cid.fwrev);
 293 MMC_DEV_ATTR(hwrev, "0x%x\n", card->cid.hwrev);
 294 MMC_DEV_ATTR(manfid, "0x%06x\n", card->cid.manfid);
 295 MMC_DEV_ATTR(name, "%s\n", card->cid.prod_name);
 296 MMC_DEV_ATTR(oemid, "0x%04x\n", card->cid.oemid);
 297 MMC_DEV_ATTR(serial, "0x%08x\n", card->cid.serial);
 298
 299
 300 static struct attribute *sd_std_attrs[] = {
 301         &dev_attr_cid.attr,
 302         &dev_attr_csd.attr,
 303         &dev_attr_scr.attr,
 304         &dev_attr_date.attr,
 305         &dev_attr_fwrev.attr,
 306         &dev_attr_hwrev.attr,
 307         &dev_attr_manfid.attr,
 308         &dev_attr_name.attr,
 309         &dev_attr_oemid.attr,
 310         &dev_attr_serial.attr,
 311         NULL,
 312 };
 313
 314 static struct attribute_group sd_std_attr_group = {
 315         .attrs = sd_std_attrs,
 316 };
 317
 318 static const struct attribute_group *sd_attr_groups[] = {
 319         &sd_std_attr_group,
 320         NULL,
 321 };
 322
 323 static struct device_type sd_type = {
 324         .groups = sd_attr_groups,
 325 };
 326
 327 /*
 328  * Handle the detection and initialisation of a card.
 329  *
 330  * In the case of a resume, "oldcard" will contain the card
 331  * we're trying to reinitialise.
 332  */
 333 static int mmc_sd_init_card(struct mmc_host *host, u32 ocr,
 334         struct mmc_card *oldcard)
 335 {
 336         struct mmc_card *card;
 337         int err;
 338         u32 cid[4];
 339         unsigned int max_dtr;
 340
 341         BUG_ON(!host);
 342         WARN_ON(!host->claimed);
 343
 344         /*
 345          * Since we're changing the OCR value, we seem to
 346          * need to tell some cards to go back to the idle
 347          * state.  We wait 1ms to give cards time to
 348          * respond.
 349          */
 350         mmc_go_idle(host);
 351
 352         /*
 353          * If SD_SEND_IF_COND indicates an SD 2.0
 354          * compliant card and we should set bit 30
 355          * of the ocr to indicate that we can handle
 356          * block-addressed SDHC cards.
 357          */
 358         err = mmc_send_if_cond(host, ocr);
 359         if (!err)
 360                 ocr |= 1 << 30;
 361
 362         err = mmc_send_app_op_cond(host, ocr, NULL);
 363         if (err)
 364                 goto err;
 365
 366         /*
 367          * Fetch CID from card.
 368          */
 369         if (mmc_host_is_spi(host))
 370                 err = mmc_send_cid(host, cid);
 371         else
 372                 err = mmc_all_send_cid(host, cid);
 373         if (err)
 374                 goto err;
 375
 376         if (oldcard) {
 377                 if (memcmp(cid, oldcard->raw_cid, sizeof(cid)) != 0) {
 378                         err = -ENOENT;
 379                         goto err;
 380                 }
 381
 382                 card = oldcard;
 383         } else {
 384                 /*
 385                  * Allocate card structure.
 386                  */
 387                 card = mmc_alloc_card(host, &sd_type);
 388                 if (IS_ERR(card)) {
 389                         err = PTR_ERR(card);
 390                         goto err;
 391                 }
 392
 393                 card->type = MMC_TYPE_SD;
 394                 memcpy(card->raw_cid, cid, sizeof(card->raw_cid));
 395         }
 396
 397         /*
 398          * For native busses:  get card RCA and quit open drain mode.
 399          */
 400         if (!mmc_host_is_spi(host)) {
 401                 err = mmc_send_relative_addr(host, &card->rca);
 402                 if (err)
 403                         goto free_card;
 404
 405                 mmc_set_bus_mode(host, MMC_BUSMODE_PUSHPULL);
 406         }
 407
 408         if (!oldcard) {
 409                 /*
 410                  * Fetch CSD from card.
 411                  */
 412                 err = mmc_send_csd(card, card->raw_csd);
 413                 if (err)
 414                         goto free_card;
 415
 416                 err = mmc_decode_csd(card);
 417                 if (err)
 418                         goto free_card;
 419
 420                 mmc_decode_cid(card);
 421         }
 422
 423         /*
 424          * Select card, as all following commands rely on that.
 425          */
 426         if (!mmc_host_is_spi(host)) {
 427                 err = mmc_select_card(card);
 428                 if (err)
 429                         goto free_card;
 430         }
 431
 432         if (!oldcard) {
 433                 /*
 434                  * Fetch SCR from card.
 435                  */
 436                 err = mmc_app_send_scr(card, card->raw_scr);
 437                 if (err)
 438                         goto free_card;
 439
 440                 err = mmc_decode_scr(card);
 441                 if (err < 0)
 442                         goto free_card;
 443
 444                 /*
 445                  * Fetch switch information from card.
 446                  */
 447                 err = mmc_read_switch(card);
 448                 if (err)
 449                         goto free_card;
 450         }
 451
 452         /*
 453          * For SPI, enable CRC as appropriate.
 454          * This CRC enable is located AFTER the reading of the
 455          * card registers because some SDHC cards are not able
 456          * to provide valid CRCs for non-512-byte blocks.
 457          */
 458         if (mmc_host_is_spi(host)) {
 459                 err = mmc_spi_set_crc(host, use_spi_crc);
 460                 if (err)
 461                         goto free_card;
 462         }
 463
 464         /*
 465          * Attempt to change to high-speed (if supported)
 466          */
 467         err = mmc_switch_hs(card);
 468         if (err)
 469                 goto free_card;
 470
 471         /*
 472          * Compute bus speed.
 473          */
 474         max_dtr = (unsigned int)-1;
 475
 476         if (mmc_card_highspeed(card)) {
 477                 if (max_dtr > card->sw_caps.hs_max_dtr)
 478                         max_dtr = card->sw_caps.hs_max_dtr;
 479         } else if (max_dtr > card->csd.max_dtr) {
 480                 max_dtr = card->csd.max_dtr;
 481         }
 482
 483         mmc_set_clock(host, max_dtr);
 484
 485         /*
 486          * Switch to wider bus (if supported).
 487          */
 488         if ((host->caps & MMC_CAP_4_BIT_DATA) &&
 489                 (card->scr.bus_widths & SD_SCR_BUS_WIDTH_4)) {
 490                 err = mmc_app_set_bus_width(card, MMC_BUS_WIDTH_4);
 491                 if (err)
 492                         goto free_card;
 493
 494                 mmc_set_bus_width(host, MMC_BUS_WIDTH_4);
 495         }
 496
 497         /*
 498          * Check if read-only switch is active.
 499          */
 500         if (!oldcard) {
 501                 if (!host->ops->get_ro || host->ops->get_ro(host) < 0) {
 502                         printk(KERN_WARNING "%s: host does not "
 503                                 "support reading read-only "
 504                                 "switch. assuming write-enable.\n",
 505                                 mmc_hostname(host));
 506                 } else {
 507                         if (host->ops->get_ro(host) > 0)
 508                                 mmc_card_set_readonly(card);
 509                 }
 510         }
 511
 512         if (!oldcard)
 513                 host->card = card;
 514
 515         return 0;
 516
 517 free_card:
 518         if (!oldcard)
 519                 mmc_remove_card(card);
 520 err:
 521
 522         return err;
 523 }
 524
 525 /*
 526  * Host is being removed. Free up the current card.
 527  */
 528 static void mmc_sd_remove(struct mmc_host *host)
 529 {
 530         BUG_ON(!host);
 531         BUG_ON(!host->card);
 532
 533         mmc_remove_card(host->card);
 534         host->card = NULL;
 535 }
 536
 537 /*
 538  * Card detection callback from host.
 539  */
 540 static void mmc_sd_detect(struct mmc_host *host)
 541 {
 542         int err;
 543
 544         BUG_ON(!host);
 545         BUG_ON(!host->card);
 546
 547         mmc_claim_host(host);
 548
 549         /*
 550          * Just check if our card has been removed.
 551          */
 552         err = mmc_send_status(host->card, NULL);
 553
 554         mmc_release_host(host);
 555
 556         if (err) {
 557                 mmc_sd_remove(host);
 558
 559                 mmc_claim_host(host);
 560                 mmc_detach_bus(host);
 561                 mmc_release_host(host);
 562         }
 563 }
 564
 565 /*
 566  * Suspend callback from host.
 567  */
 568 static int mmc_sd_suspend(struct mmc_host *host)
 569 {
 570         BUG_ON(!host);
 571         BUG_ON(!host->card);
 572
 573         mmc_claim_host(host);
 574         if (!mmc_host_is_spi(host))
 575                 mmc_deselect_cards(host);
 576         host->card->state &= ~MMC_STATE_HIGHSPEED;
 577         mmc_release_host(host);
 578
 579         return 0;
 580 }
 581
 582 /*
 583  * Resume callback from host.
 584  *
 585  * This function tries to determine if the same card is still present
 586  * and, if so, restore all state to it.
 587  */
 588 static int mmc_sd_resume(struct mmc_host *host)
 589 {
 590         int err;
 591
 592         BUG_ON(!host);
 593         BUG_ON(!host->card);
 594
 595         mmc_claim_host(host);
 596         err = mmc_sd_init_card(host, host->ocr, host->card);
 597         mmc_release_host(host);
 598
 599         return err;
 600 }
 601
 602 static void mmc_sd_power_restore(struct mmc_host *host)
 603 {
 604         host->card->state &= ~MMC_STATE_HIGHSPEED;
 605         mmc_claim_host(host);
 606         mmc_sd_init_card(host, host->ocr, host->card);
 607         mmc_release_host(host);
 608 }
 609
 610 static const struct mmc_bus_ops mmc_sd_ops = {
 611         .remove = mmc_sd_remove,
 612         .detect = mmc_sd_detect,
 613         .suspend = NULL,
 614         .resume = NULL,
 615         .power_restore = mmc_sd_power_restore,
 616 };
 617
 618 static const struct mmc_bus_ops mmc_sd_ops_unsafe = {
 619         .remove = mmc_sd_remove,
 620         .detect = mmc_sd_detect,
 621         .suspend = mmc_sd_suspend,
 622         .resume = mmc_sd_resume,
 623         .power_restore = mmc_sd_power_restore,
 624 };
 625
 626 static void mmc_sd_attach_bus_ops(struct mmc_host *host)
 627 {
 628         const struct mmc_bus_ops *bus_ops;
 629
 630         if (host->caps & MMC_CAP_NONREMOVABLE || !mmc_assume_removable)
 631                 bus_ops = &mmc_sd_ops_unsafe;
 632         else
 633                 bus_ops = &mmc_sd_ops;
 634         mmc_attach_bus(host, bus_ops);
 635 }
 636
 637 /*
 638  * Starting point for SD card init.
 639  */
 640 int mmc_attach_sd(struct mmc_host *host, u32 ocr)
 641 {
 642         int err;
 643
 644         BUG_ON(!host);
 645         WARN_ON(!host->claimed);
 646
 647         mmc_sd_attach_bus_ops(host);
 648
 649         /*
 650          * We need to get OCR a different way for SPI.
 651          */
 652         if (mmc_host_is_spi(host)) {
 653                 mmc_go_idle(host);
 654
 655                 err = mmc_spi_read_ocr(host, 0, &ocr);
 656                 if (err)
 657                         goto err;
 658         }
 659
 660         /*
 661          * Sanity check the voltages that the card claims to
 662          * support.
 663          */
 664         if (ocr & 0x7F) {
 665                 printk(KERN_WARNING "%s: card claims to support voltages "
 666                        "below the defined range. These will be ignored.\n",
 667                        mmc_hostname(host));
 668                 ocr &= ~0x7F;
 669         }
 670
 671         if (ocr & MMC_VDD_165_195) {
 672                 printk(KERN_WARNING "%s: SD card claims to support the "
 673                        "incompletely defined 'low voltage range'. This "
 674                        "will be ignored.\n", mmc_hostname(host));
 675                 ocr &= ~MMC_VDD_165_195;
 676         }
 677
 678         host->ocr = mmc_select_voltage(host, ocr);
 679
 680         /*
 681          * Can we support the voltage(s) of the card(s)?
 682          */
 683         if (!host->ocr) {
 684                 err = -EINVAL;
 685                 goto err;
 686         }
 687
 688         /*
 689          * Detect and init the card.
 690          */
 691         err = mmc_sd_init_card(host, host->ocr, NULL);
 692         if (err)
 693                 goto err;
 694
 695         mmc_release_host(host);
 696
 697         err = mmc_add_card(host->card);
 698         if (err)
 699                 goto remove_card;
 700
 701         return 0;
 702
 703 remove_card:
 704         mmc_remove_card(host->card);
 705         host->card = NULL;
 706         mmc_claim_host(host);
 707 err:
 708         mmc_detach_bus(host);
 709         mmc_release_host(host);
 710
 711         printk(KERN_ERR "%s: error %d whilst initialising SD card\n",
 712                 mmc_hostname(host), err);
 713
 714         return err;
 715 }
 716