drivers/mmc/dw_mmc.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * (C) Copyright 2012 SAMSUNG Electronics
   4  * Jaehoon Chung <jh80.chung@samsung.com>
   5  * Rajeshawari Shinde <rajeshwari.s@samsung.com>
   6  */
   7
   8 #include <bouncebuf.h>
   9 #include <common.h>
  10 #include <errno.h>
  11 #include <malloc.h>
  12 #include <memalign.h>
  13 #include <mmc.h>
  14 #include <dwmmc.h>
  15 #include <wait_bit.h>
  16 #include <power/regulator.h>
  17
  18 #define PAGE_SIZE 4096
  19
  20 static int dwmci_wait_reset(struct dwmci_host *host, u32 value)
  21 {
  22         unsigned long timeout = 1000;
  23         u32 ctrl;
  24
  25         dwmci_writel(host, DWMCI_CTRL, value);
  26
  27         while (timeout--) {
  28                 ctrl = dwmci_readl(host, DWMCI_CTRL);
  29                 if (!(ctrl & DWMCI_RESET_ALL))
  30                         return 1;
  31         }
  32         return 0;
  33 }
  34
  35 static void dwmci_set_idma_desc(struct dwmci_idmac *idmac,
  36                 u32 desc0, u32 desc1, u32 desc2)
  37 {
  38         struct dwmci_idmac *desc = idmac;
  39
  40         desc->flags = desc0;
  41         desc->cnt = desc1;
  42         desc->addr = desc2;
  43         desc->next_addr = (ulong)desc + sizeof(struct dwmci_idmac);
  44 }
  45
  46 static void dwmci_prepare_data(struct dwmci_host *host,
  47                                struct mmc_data *data,
  48                                struct dwmci_idmac *cur_idmac,
  49                                void *bounce_buffer)
  50 {
  51         unsigned long ctrl;
  52         unsigned int i = 0, flags, cnt, blk_cnt;
  53         ulong data_start, data_end;
  54
  55
  56         blk_cnt = data->blocks;
  57
  58         dwmci_wait_reset(host, DWMCI_CTRL_FIFO_RESET);
  59
  60         /* Clear IDMAC interrupt */
  61         dwmci_writel(host, DWMCI_IDSTS, 0xFFFFFFFF);
  62
  63         data_start = (ulong)cur_idmac;
  64         dwmci_writel(host, DWMCI_DBADDR, (ulong)cur_idmac);
  65
  66         do {
  67                 flags = DWMCI_IDMAC_OWN | DWMCI_IDMAC_CH ;
  68                 flags |= (i == 0) ? DWMCI_IDMAC_FS : 0;
  69                 if (blk_cnt <= 8) {
  70                         flags |= DWMCI_IDMAC_LD;
  71                         cnt = data->blocksize * blk_cnt;
  72                 } else
  73                         cnt = data->blocksize * 8;
  74
  75                 dwmci_set_idma_desc(cur_idmac, flags, cnt,
  76                                     (ulong)bounce_buffer + (i * PAGE_SIZE));
  77
  78                 cur_idmac++;
  79                 if (blk_cnt <= 8)
  80                         break;
  81                 blk_cnt -= 8;
  82                 i++;
  83         } while(1);
  84
  85         data_end = (ulong)cur_idmac;
  86         flush_dcache_range(data_start, roundup(data_end, ARCH_DMA_MINALIGN));
  87
  88         ctrl = dwmci_readl(host, DWMCI_CTRL);
  89         ctrl |= DWMCI_IDMAC_EN | DWMCI_DMA_EN;
  90         dwmci_writel(host, DWMCI_CTRL, ctrl);
  91
  92         ctrl = dwmci_readl(host, DWMCI_BMOD);
  93         ctrl |= DWMCI_BMOD_IDMAC_FB | DWMCI_BMOD_IDMAC_EN;
  94         dwmci_writel(host, DWMCI_BMOD, ctrl);
  95
  96         dwmci_writel(host, DWMCI_BLKSIZ, data->blocksize);
  97         dwmci_writel(host, DWMCI_BYTCNT, data->blocksize * data->blocks);
  98 }
  99
 100 static int dwmci_fifo_ready(struct dwmci_host *host, u32 bit, u32 *len)
 101 {
 102         u32 timeout = 20000;
 103
 104         *len = dwmci_readl(host, DWMCI_STATUS);
 105         while (--timeout && (*len & bit)) {
 106                 udelay(200);
 107                 *len = dwmci_readl(host, DWMCI_STATUS);
 108         }
 109
 110         if (!timeout) {
 111                 debug("%s: FIFO underflow timeout\n", __func__);
 112                 return -ETIMEDOUT;
 113         }
 114
 115         return 0;
 116 }
 117
 118 static unsigned int dwmci_get_timeout(struct mmc *mmc, const unsigned int size)
 119 {
 120         unsigned int timeout;
 121
 122         timeout = size * 8 * 1000;      /* counting in bits and msec */
 123         timeout *= 2;                   /* wait twice as long */
 124         timeout /= mmc->clock;
 125         timeout /= mmc->bus_width;
 126         timeout /= mmc->ddr_mode ? 2 : 1;
 127         timeout = (timeout < 1000) ? 1000 : timeout;
 128
 129         return timeout;
 130 }
 131
 132 static int dwmci_data_transfer(struct dwmci_host *host, struct mmc_data *data)
 133 {
 134         struct mmc *mmc = host->mmc;
 135         int ret = 0;
 136         u32 timeout, mask, size, i, len = 0;
 137         u32 *buf = NULL;
 138         ulong start = get_timer(0);
 139         u32 fifo_depth = (((host->fifoth_val & RX_WMARK_MASK) >>
 140                             RX_WMARK_SHIFT) + 1) * 2;
 141
 142         size = data->blocksize * data->blocks;
 143         if (data->flags == MMC_DATA_READ)
 144                 buf = (unsigned int *)data->dest;
 145         else
 146                 buf = (unsigned int *)data->src;
 147
 148         timeout = dwmci_get_timeout(mmc, size);
 149
 150         size /= 4;
 151
 152         for (;;) {
 153                 mask = dwmci_readl(host, DWMCI_RINTSTS);
 154                 /* Error during data transfer. */
 155                 if (mask & (DWMCI_DATA_ERR | DWMCI_DATA_TOUT)) {
 156                         debug("%s: DATA ERROR!\n", __func__);
 157                         ret = -EINVAL;
 158                         break;
 159                 }
 160
 161                 if (host->fifo_mode && size) {
 162                         len = 0;
 163                         if (data->flags == MMC_DATA_READ &&
 164                             (mask & DWMCI_INTMSK_RXDR)) {
 165                                 while (size) {
 166                                         ret = dwmci_fifo_ready(host,
 167                                                         DWMCI_FIFO_EMPTY,
 168                                                         &len);
 169                                         if (ret < 0)
 170                                                 break;
 171
 172                                         len = (len >> DWMCI_FIFO_SHIFT) &
 173                                                     DWMCI_FIFO_MASK;
 174                                         len = min(size, len);
 175                                         for (i = 0; i < len; i++)
 176                                                 *buf++ =
 177                                                 dwmci_readl(host, DWMCI_DATA);
 178                                         size = size > len ? (size - len) : 0;
 179                                 }
 180                                 dwmci_writel(host, DWMCI_RINTSTS,
 181                                              DWMCI_INTMSK_RXDR);
 182                         } else if (data->flags == MMC_DATA_WRITE &&
 183                                    (mask & DWMCI_INTMSK_TXDR)) {
 184                                 while (size) {
 185                                         ret = dwmci_fifo_ready(host,
 186                                                         DWMCI_FIFO_FULL,
 187                                                         &len);
 188                                         if (ret < 0)
 189                                                 break;
 190
 191                                         len = fifo_depth - ((len >>
 192                                                    DWMCI_FIFO_SHIFT) &
 193                                                    DWMCI_FIFO_MASK);
 194                                         len = min(size, len);
 195                                         for (i = 0; i < len; i++)
 196                                                 dwmci_writel(host, DWMCI_DATA,
 197                                                              *buf++);
 198                                         size = size > len ? (size - len) : 0;
 199                                 }
 200                                 dwmci_writel(host, DWMCI_RINTSTS,
 201                                              DWMCI_INTMSK_TXDR);
 202                         }
 203                 }
 204
 205                 /* Data arrived correctly. */
 206                 if (mask & DWMCI_INTMSK_DTO) {
 207                         ret = 0;
 208                         break;
 209                 }
 210
 211                 /* Check for timeout. */
 212                 if (get_timer(start) > timeout) {
 213                         debug("%s: Timeout waiting for data!\n",
 214                               __func__);
 215                         ret = -ETIMEDOUT;
 216                         break;
 217                 }
 218         }
 219
 220         dwmci_writel(host, DWMCI_RINTSTS, mask);
 221
 222         return ret;
 223 }
 224
 225 static int dwmci_set_transfer_mode(struct dwmci_host *host,
 226                 struct mmc_data *data)
 227 {
 228         unsigned long mode;
 229
 230         mode = DWMCI_CMD_DATA_EXP;
 231         if (data->flags & MMC_DATA_WRITE)
 232                 mode |= DWMCI_CMD_RW;
 233
 234         return mode;
 235 }
 236
 237 #ifdef CONFIG_DM_MMC
 238 static int dwmci_send_cmd(struct udevice *dev, struct mmc_cmd *cmd,
 239                    struct mmc_data *data)
 240 {
 241         struct mmc *mmc = mmc_get_mmc_dev(dev);
 242 #else
 243 static int dwmci_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd,
 244                 struct mmc_data *data)
 245 {
 246 #endif
 247         struct dwmci_host *host = mmc->priv;
 248         ALLOC_CACHE_ALIGN_BUFFER(struct dwmci_idmac, cur_idmac,
 249                                  data ? DIV_ROUND_UP(data->blocks, 8) : 0);
 250         int ret = 0, flags = 0, i;
 251         unsigned int timeout = 500;
 252         u32 retry = 100000;
 253         u32 mask, ctrl;
 254         ulong start = get_timer(0);
 255         struct bounce_buffer bbstate;
 256
 257         while (dwmci_readl(host, DWMCI_STATUS) & DWMCI_BUSY) {
 258                 if (get_timer(start) > timeout) {
 259                         debug("%s: Timeout on data busy\n", __func__);
 260                         return -ETIMEDOUT;
 261                 }
 262         }
 263
 264         dwmci_writel(host, DWMCI_RINTSTS, DWMCI_INTMSK_ALL);
 265
 266         if (data) {
 267                 if (host->fifo_mode) {
 268                         dwmci_writel(host, DWMCI_BLKSIZ, data->blocksize);
 269                         dwmci_writel(host, DWMCI_BYTCNT,
 270                                      data->blocksize * data->blocks);
 271                         dwmci_wait_reset(host, DWMCI_CTRL_FIFO_RESET);
 272                 } else {
 273                         if (data->flags == MMC_DATA_READ) {
 274                                 ret = bounce_buffer_start(&bbstate,
 275                                                 (void*)data->dest,
 276                                                 data->blocksize *
 277                                                 data->blocks, GEN_BB_WRITE);
 278                         } else {
 279                                 ret = bounce_buffer_start(&bbstate,
 280                                                 (void*)data->src,
 281                                                 data->blocksize *
 282                                                 data->blocks, GEN_BB_READ);
 283                         }
 284
 285                         if (ret)
 286                                 return ret;
 287
 288                         dwmci_prepare_data(host, data, cur_idmac,
 289                                            bbstate.bounce_buffer);
 290                 }
 291         }
 292
 293         dwmci_writel(host, DWMCI_CMDARG, cmd->cmdarg);
 294
 295         if (data)
 296                 flags = dwmci_set_transfer_mode(host, data);
 297
 298         if ((cmd->resp_type & MMC_RSP_136) && (cmd->resp_type & MMC_RSP_BUSY))
 299                 return -1;
 300
 301         if (cmd->cmdidx == MMC_CMD_STOP_TRANSMISSION)
 302                 flags |= DWMCI_CMD_ABORT_STOP;
 303         else
 304                 flags |= DWMCI_CMD_PRV_DAT_WAIT;
 305
 306         if (cmd->resp_type & MMC_RSP_PRESENT) {
 307                 flags |= DWMCI_CMD_RESP_EXP;
 308                 if (cmd->resp_type & MMC_RSP_136)
 309                         flags |= DWMCI_CMD_RESP_LENGTH;
 310         }
 311
 312         if (cmd->resp_type & MMC_RSP_CRC)
 313                 flags |= DWMCI_CMD_CHECK_CRC;
 314
 315         flags |= (cmd->cmdidx | DWMCI_CMD_START | DWMCI_CMD_USE_HOLD_REG);
 316
 317         debug("Sending CMD%d\n",cmd->cmdidx);
 318
 319         dwmci_writel(host, DWMCI_CMD, flags);
 320
 321         for (i = 0; i < retry; i++) {
 322                 mask = dwmci_readl(host, DWMCI_RINTSTS);
 323                 if (mask & DWMCI_INTMSK_CDONE) {
 324                         if (!data)
 325                                 dwmci_writel(host, DWMCI_RINTSTS, mask);
 326                         break;
 327                 }
 328         }
 329
 330         if (i == retry) {
 331                 debug("%s: Timeout.\n", __func__);
 332                 return -ETIMEDOUT;
 333         }
 334
 335         if (mask & DWMCI_INTMSK_RTO) {
 336                 /*
 337                  * Timeout here is not necessarily fatal. (e)MMC cards
 338                  * will splat here when they receive CMD55 as they do
 339                  * not support this command and that is exactly the way
 340                  * to tell them apart from SD cards. Thus, this output
 341                  * below shall be debug(). eMMC cards also do not favor
 342                  * CMD8, please keep that in mind.
 343                  */
 344                 debug("%s: Response Timeout.\n", __func__);
 345                 return -ETIMEDOUT;
 346         } else if (mask & DWMCI_INTMSK_RE) {
 347                 debug("%s: Response Error.\n", __func__);
 348                 return -EIO;
 349         } else if ((cmd->resp_type & MMC_RSP_CRC) &&
 350                    (mask & DWMCI_INTMSK_RCRC)) {
 351                 debug("%s: Response CRC Error.\n", __func__);
 352                 return -EIO;
 353         }
 354
 355
 356         if (cmd->resp_type & MMC_RSP_PRESENT) {
 357                 if (cmd->resp_type & MMC_RSP_136) {
 358                         cmd->response[0] = dwmci_readl(host, DWMCI_RESP3);
 359                         cmd->response[1] = dwmci_readl(host, DWMCI_RESP2);
 360                         cmd->response[2] = dwmci_readl(host, DWMCI_RESP1);
 361                         cmd->response[3] = dwmci_readl(host, DWMCI_RESP0);
 362                 } else {
 363                         cmd->response[0] = dwmci_readl(host, DWMCI_RESP0);
 364                 }
 365         }
 366
 367         if (data) {
 368                 ret = dwmci_data_transfer(host, data);
 369
 370                 /* only dma mode need it */
 371                 if (!host->fifo_mode) {
 372                         if (data->flags == MMC_DATA_READ)
 373                                 mask = DWMCI_IDINTEN_RI;
 374                         else
 375                                 mask = DWMCI_IDINTEN_TI;
 376                         ret = wait_for_bit_le32(host->ioaddr + DWMCI_IDSTS,
 377                                                 mask, true, 1000, false);
 378                         if (ret)
 379                                 debug("%s: DWMCI_IDINTEN mask 0x%x timeout.\n",
 380                                       __func__, mask);
 381                         /* clear interrupts */
 382                         dwmci_writel(host, DWMCI_IDSTS, DWMCI_IDINTEN_MASK);
 383
 384                         ctrl = dwmci_readl(host, DWMCI_CTRL);
 385                         ctrl &= ~(DWMCI_DMA_EN);
 386                         dwmci_writel(host, DWMCI_CTRL, ctrl);
 387                         bounce_buffer_stop(&bbstate);
 388                 }
 389         }
 390
 391         udelay(100);
 392
 393         return ret;
 394 }
 395
 396 static int dwmci_setup_bus(struct dwmci_host *host, u32 freq)
 397 {
 398         u32 div, status;
 399         int timeout = 10000;
 400         unsigned long sclk;
 401
 402         if ((freq == host->clock) || (freq == 0))
 403                 return 0;
 404         /*
 405          * If host->get_mmc_clk isn't defined,
 406          * then assume that host->bus_hz is source clock value.
 407          * host->bus_hz should be set by user.
 408          */
 409         if (host->get_mmc_clk)
 410                 sclk = host->get_mmc_clk(host, freq);
 411         else if (host->bus_hz)
 412                 sclk = host->bus_hz;
 413         else {
 414                 debug("%s: Didn't get source clock value.\n", __func__);
 415                 return -EINVAL;
 416         }
 417
 418         if (sclk == freq)
 419                 div = 0;        /* bypass mode */
 420         else
 421                 div = DIV_ROUND_UP(sclk, 2 * freq);
 422
 423         dwmci_writel(host, DWMCI_CLKENA, 0);
 424         dwmci_writel(host, DWMCI_CLKSRC, 0);
 425
 426         dwmci_writel(host, DWMCI_CLKDIV, div);
 427         dwmci_writel(host, DWMCI_CMD, DWMCI_CMD_PRV_DAT_WAIT |
 428                         DWMCI_CMD_UPD_CLK | DWMCI_CMD_START);
 429
 430         do {
 431                 status = dwmci_readl(host, DWMCI_CMD);
 432                 if (timeout-- < 0) {
 433                         debug("%s: Timeout!\n", __func__);
 434                         return -ETIMEDOUT;
 435                 }
 436         } while (status & DWMCI_CMD_START);
 437
 438         dwmci_writel(host, DWMCI_CLKENA, DWMCI_CLKEN_ENABLE |
 439                         DWMCI_CLKEN_LOW_PWR);
 440
 441         dwmci_writel(host, DWMCI_CMD, DWMCI_CMD_PRV_DAT_WAIT |
 442                         DWMCI_CMD_UPD_CLK | DWMCI_CMD_START);
 443
 444         timeout = 10000;
 445         do {
 446                 status = dwmci_readl(host, DWMCI_CMD);
 447                 if (timeout-- < 0) {
 448                         debug("%s: Timeout!\n", __func__);
 449                         return -ETIMEDOUT;
 450                 }
 451         } while (status & DWMCI_CMD_START);
 452
 453         host->clock = freq;
 454
 455         return 0;
 456 }
 457
 458 #ifdef CONFIG_DM_MMC
 459 static int dwmci_set_ios(struct udevice *dev)
 460 {
 461         struct mmc *mmc = mmc_get_mmc_dev(dev);
 462 #else
 463 static int dwmci_set_ios(struct mmc *mmc)
 464 {
 465 #endif
 466         struct dwmci_host *host = (struct dwmci_host *)mmc->priv;
 467         u32 ctype, regs;
 468
 469         debug("Buswidth = %d, clock: %d\n", mmc->bus_width, mmc->clock);
 470
 471         dwmci_setup_bus(host, mmc->clock);
 472         switch (mmc->bus_width) {
 473         case 8:
 474                 ctype = DWMCI_CTYPE_8BIT;
 475                 break;
 476         case 4:
 477                 ctype = DWMCI_CTYPE_4BIT;
 478                 break;
 479         default:
 480                 ctype = DWMCI_CTYPE_1BIT;
 481                 break;
 482         }
 483
 484         dwmci_writel(host, DWMCI_CTYPE, ctype);
 485
 486         regs = dwmci_readl(host, DWMCI_UHS_REG);
 487         if (mmc->ddr_mode)
 488                 regs |= DWMCI_DDR_MODE;
 489         else
 490                 regs &= ~DWMCI_DDR_MODE;
 491
 492         dwmci_writel(host, DWMCI_UHS_REG, regs);
 493
 494         if (host->clksel)
 495                 host->clksel(host);
 496
 497 #if CONFIG_IS_ENABLED(DM_REGULATOR)
 498         if (mmc->vqmmc_supply) {
 499                 int ret;
 500
 501                 if (mmc->signal_voltage == MMC_SIGNAL_VOLTAGE_180)
 502                         regulator_set_value(mmc->vqmmc_supply, 1800000);
 503                 else
 504                         regulator_set_value(mmc->vqmmc_supply, 3300000);
 505
 506                 ret = regulator_set_enable_if_allowed(mmc->vqmmc_supply, true);
 507                 if (ret)
 508                         return ret;
 509         }
 510 #endif
 511
 512         return 0;
 513 }
 514
 515 static int dwmci_init(struct mmc *mmc)
 516 {
 517         struct dwmci_host *host = mmc->priv;
 518
 519         if (host->board_init)
 520                 host->board_init(host);
 521
 522         dwmci_writel(host, DWMCI_PWREN, 1);
 523
 524         if (!dwmci_wait_reset(host, DWMCI_RESET_ALL)) {
 525                 debug("%s[%d] Fail-reset!!\n", __func__, __LINE__);
 526                 return -EIO;
 527         }
 528
 529         /* Enumerate at 400KHz */
 530         dwmci_setup_bus(host, mmc->cfg->f_min);
 531
 532         dwmci_writel(host, DWMCI_RINTSTS, 0xFFFFFFFF);
 533         dwmci_writel(host, DWMCI_INTMASK, 0);
 534
 535         dwmci_writel(host, DWMCI_TMOUT, 0xFFFFFFFF);
 536
 537         dwmci_writel(host, DWMCI_IDINTEN, 0);
 538         dwmci_writel(host, DWMCI_BMOD, 1);
 539
 540         if (!host->fifoth_val) {
 541                 uint32_t fifo_size;
 542
 543                 fifo_size = dwmci_readl(host, DWMCI_FIFOTH);
 544                 fifo_size = ((fifo_size & RX_WMARK_MASK) >> RX_WMARK_SHIFT) + 1;
 545                 host->fifoth_val = MSIZE(0x2) | RX_WMARK(fifo_size / 2 - 1) |
 546                                 TX_WMARK(fifo_size / 2);
 547         }
 548         dwmci_writel(host, DWMCI_FIFOTH, host->fifoth_val);
 549
 550         dwmci_writel(host, DWMCI_CLKENA, 0);
 551         dwmci_writel(host, DWMCI_CLKSRC, 0);
 552
 553         if (!host->fifo_mode)
 554                 dwmci_writel(host, DWMCI_IDINTEN, DWMCI_IDINTEN_MASK);
 555
 556         return 0;
 557 }
 558
 559 #ifdef CONFIG_DM_MMC
 560 int dwmci_probe(struct udevice *dev)
 561 {
 562         struct mmc *mmc = mmc_get_mmc_dev(dev);
 563
 564         return dwmci_init(mmc);
 565 }
 566
 567 const struct dm_mmc_ops dm_dwmci_ops = {
 568         .send_cmd       = dwmci_send_cmd,
 569         .set_ios        = dwmci_set_ios,
 570 };
 571
 572 #else
 573 static const struct mmc_ops dwmci_ops = {
 574         .send_cmd       = dwmci_send_cmd,
 575         .set_ios        = dwmci_set_ios,
 576         .init           = dwmci_init,
 577 };
 578 #endif
 579
 580 void dwmci_setup_cfg(struct mmc_config *cfg, struct dwmci_host *host,
 581                 u32 max_clk, u32 min_clk)
 582 {
 583         cfg->name = host->name;
 584 #ifndef CONFIG_DM_MMC
 585         cfg->ops = &dwmci_ops;
 586 #endif
 587         cfg->f_min = min_clk;
 588         cfg->f_max = max_clk;
 589
 590         cfg->voltages = MMC_VDD_32_33 | MMC_VDD_33_34 | MMC_VDD_165_195;
 591
 592         cfg->host_caps = host->caps;
 593
 594         if (host->buswidth == 8) {
 595                 cfg->host_caps |= MMC_MODE_8BIT;
 596                 cfg->host_caps &= ~MMC_MODE_4BIT;
 597         } else {
 598                 cfg->host_caps |= MMC_MODE_4BIT;
 599                 cfg->host_caps &= ~MMC_MODE_8BIT;
 600         }
 601         cfg->host_caps |= MMC_MODE_HS | MMC_MODE_HS_52MHz;
 602
 603         cfg->b_max = CONFIG_SYS_MMC_MAX_BLK_COUNT;
 604 }
 605
 606 #ifdef CONFIG_BLK
 607 int dwmci_bind(struct udevice *dev, struct mmc *mmc, struct mmc_config *cfg)
 608 {
 609         return mmc_bind(dev, mmc, cfg);
 610 }
 611 #else
 612 int add_dwmci(struct dwmci_host *host, u32 max_clk, u32 min_clk)
 613 {
 614         dwmci_setup_cfg(&host->cfg, host, max_clk, min_clk);
 615
 616         host->mmc = mmc_create(&host->cfg, host);
 617         if (host->mmc == NULL)
 618                 return -1;
 619
 620         return 0;
 621 }
 622 #endif