drivers/mmc/host/moxart-mmc.c

   1 /*
   2  * MOXA ART MMC host driver.
   3  *
   4  * Copyright (C) 2014 Jonas Jensen
   5  *
   6  * Jonas Jensen <jonas.jensen@gmail.com>
   7  *
   8  * Based on code from
   9  * Moxa Technologies Co., Ltd. <www.moxa.com>
  10  *
  11  * This file is licensed under the terms of the GNU General Public
  12  * License version 2.  This program is licensed "as is" without any
  13  * warranty of any kind, whether express or implied.
  14  */
  15
  16 #include <linux/module.h>
  17 #include <linux/init.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/delay.h>
  20 #include <linux/errno.h>
  21 #include <linux/interrupt.h>
  22 #include <linux/blkdev.h>
  23 #include <linux/dma-mapping.h>
  24 #include <linux/dmaengine.h>
  25 #include <linux/mmc/host.h>
  26 #include <linux/mmc/sd.h>
  27 #include <linux/sched.h>
  28 #include <linux/io.h>
  29 #include <linux/of_address.h>
  30 #include <linux/of_irq.h>
  31 #include <linux/clk.h>
  32 #include <linux/bitops.h>
  33 #include <linux/of_dma.h>
  34 #include <linux/spinlock.h>
  35
  36 #define REG_COMMAND             0
  37 #define REG_ARGUMENT            4
  38 #define REG_RESPONSE0           8
  39 #define REG_RESPONSE1           12
  40 #define REG_RESPONSE2           16
  41 #define REG_RESPONSE3           20
  42 #define REG_RESPONSE_COMMAND    24
  43 #define REG_DATA_CONTROL        28
  44 #define REG_DATA_TIMER          32
  45 #define REG_DATA_LENGTH         36
  46 #define REG_STATUS              40
  47 #define REG_CLEAR               44
  48 #define REG_INTERRUPT_MASK      48
  49 #define REG_POWER_CONTROL       52
  50 #define REG_CLOCK_CONTROL       56
  51 #define REG_BUS_WIDTH           60
  52 #define REG_DATA_WINDOW         64
  53 #define REG_FEATURE             68
  54 #define REG_REVISION            72
  55
  56 /* REG_COMMAND */
  57 #define CMD_SDC_RESET           BIT(10)
  58 #define CMD_EN                  BIT(9)
  59 #define CMD_APP_CMD             BIT(8)
  60 #define CMD_LONG_RSP            BIT(7)
  61 #define CMD_NEED_RSP            BIT(6)
  62 #define CMD_IDX_MASK            0x3f
  63
  64 /* REG_RESPONSE_COMMAND */
  65 #define RSP_CMD_APP             BIT(6)
  66 #define RSP_CMD_IDX_MASK        0x3f
  67
  68 /* REG_DATA_CONTROL */
  69 #define DCR_DATA_FIFO_RESET     BIT(8)
  70 #define DCR_DATA_THRES          BIT(7)
  71 #define DCR_DATA_EN             BIT(6)
  72 #define DCR_DMA_EN              BIT(5)
  73 #define DCR_DATA_WRITE          BIT(4)
  74 #define DCR_BLK_SIZE            0x0f
  75
  76 /* REG_DATA_LENGTH */
  77 #define DATA_LEN_MASK           0xffffff
  78
  79 /* REG_STATUS */
  80 #define WRITE_PROT              BIT(12)
  81 #define CARD_DETECT             BIT(11)
  82 /* 1-10 below can be sent to either registers, interrupt or clear. */
  83 #define CARD_CHANGE             BIT(10)
  84 #define FIFO_ORUN               BIT(9)
  85 #define FIFO_URUN               BIT(8)
  86 #define DATA_END                BIT(7)
  87 #define CMD_SENT                BIT(6)
  88 #define DATA_CRC_OK             BIT(5)
  89 #define RSP_CRC_OK              BIT(4)
  90 #define DATA_TIMEOUT            BIT(3)
  91 #define RSP_TIMEOUT             BIT(2)
  92 #define DATA_CRC_FAIL           BIT(1)
  93 #define RSP_CRC_FAIL            BIT(0)
  94
  95 #define MASK_RSP                (RSP_TIMEOUT | RSP_CRC_FAIL | \
  96                                  RSP_CRC_OK  | CARD_DETECT  | CMD_SENT)
  97
  98 #define MASK_DATA               (DATA_CRC_OK   | DATA_END | \
  99                                  DATA_CRC_FAIL | DATA_TIMEOUT)
 100
 101 #define MASK_INTR_PIO           (FIFO_URUN | FIFO_ORUN | CARD_CHANGE)
 102
 103 /* REG_POWER_CONTROL */
 104 #define SD_POWER_ON             BIT(4)
 105 #define SD_POWER_MASK           0x0f
 106
 107 /* REG_CLOCK_CONTROL */
 108 #define CLK_HISPD               BIT(9)
 109 #define CLK_OFF                 BIT(8)
 110 #define CLK_SD                  BIT(7)
 111 #define CLK_DIV_MASK            0x7f
 112
 113 /* REG_BUS_WIDTH */
 114 #define BUS_WIDTH_8             BIT(2)
 115 #define BUS_WIDTH_4             BIT(1)
 116 #define BUS_WIDTH_1             BIT(0)
 117
 118 #define MMC_VDD_360             23
 119 #define MIN_POWER               (MMC_VDD_360 - SD_POWER_MASK)
 120 #define MAX_RETRIES             500000
 121
 122 struct moxart_host {
 123         spinlock_t                      lock;
 124
 125         void __iomem                    *base;
 126
 127         phys_addr_t                     reg_phys;
 128
 129         struct dma_chan                 *dma_chan_tx;
 130         struct dma_chan                 *dma_chan_rx;
 131         struct dma_async_tx_descriptor  *tx_desc;
 132         struct mmc_host                 *mmc;
 133         struct mmc_request              *mrq;
 134         struct scatterlist              *cur_sg;
 135         struct completion               dma_complete;
 136         struct completion               pio_complete;
 137
 138         u32                             num_sg;
 139         u32                             data_remain;
 140         u32                             data_len;
 141         u32                             fifo_width;
 142         u32                             timeout;
 143         u32                             rate;
 144
 145         long                            sysclk;
 146
 147         bool                            have_dma;
 148         bool                            is_removed;
 149 };
 150
 151 static inline void moxart_init_sg(struct moxart_host *host,
 152                                   struct mmc_data *data)
 153 {
 154         host->cur_sg = data->sg;
 155         host->num_sg = data->sg_len;
 156         host->data_remain = host->cur_sg->length;
 157
 158         if (host->data_remain > host->data_len)
 159                 host->data_remain = host->data_len;
 160 }
 161
 162 static inline int moxart_next_sg(struct moxart_host *host)
 163 {
 164         int remain;
 165         struct mmc_data *data = host->mrq->cmd->data;
 166
 167         host->cur_sg++;
 168         host->num_sg--;
 169
 170         if (host->num_sg > 0) {
 171                 host->data_remain = host->cur_sg->length;
 172                 remain = host->data_len - data->bytes_xfered;
 173                 if (remain > 0 && remain < host->data_remain)
 174                         host->data_remain = remain;
 175         }
 176
 177         return host->num_sg;
 178 }
 179
 180 static int moxart_wait_for_status(struct moxart_host *host,
 181                                   u32 mask, u32 *status)
 182 {
 183         int ret = -ETIMEDOUT;
 184         u32 i;
 185
 186         for (i = 0; i < MAX_RETRIES; i++) {
 187                 *status = readl(host->base + REG_STATUS);
 188                 if (!(*status & mask)) {
 189                         udelay(5);
 190                         continue;
 191                 }
 192                 writel(*status & mask, host->base + REG_CLEAR);
 193                 ret = 0;
 194                 break;
 195         }
 196
 197         if (ret)
 198                 dev_err(mmc_dev(host->mmc), "timed out waiting for status\n");
 199
 200         return ret;
 201 }
 202
 203
 204 static void moxart_send_command(struct moxart_host *host,
 205         struct mmc_command *cmd)
 206 {
 207         u32 status, cmdctrl;
 208
 209         writel(RSP_TIMEOUT  | RSP_CRC_OK |
 210                RSP_CRC_FAIL | CMD_SENT, host->base + REG_CLEAR);
 211         writel(cmd->arg, host->base + REG_ARGUMENT);
 212
 213         cmdctrl = cmd->opcode & CMD_IDX_MASK;
 214         if (cmdctrl == SD_APP_SET_BUS_WIDTH    || cmdctrl == SD_APP_OP_COND   ||
 215             cmdctrl == SD_APP_SEND_SCR         || cmdctrl == SD_APP_SD_STATUS ||
 216             cmdctrl == SD_APP_SEND_NUM_WR_BLKS)
 217                 cmdctrl |= CMD_APP_CMD;
 218
 219         if (cmd->flags & MMC_RSP_PRESENT)
 220                 cmdctrl |= CMD_NEED_RSP;
 221
 222         if (cmd->flags & MMC_RSP_136)
 223                 cmdctrl |= CMD_LONG_RSP;
 224
 225         writel(cmdctrl | CMD_EN, host->base + REG_COMMAND);
 226
 227         if (moxart_wait_for_status(host, MASK_RSP, &status) == -ETIMEDOUT)
 228                 cmd->error = -ETIMEDOUT;
 229
 230         if (status & RSP_TIMEOUT) {
 231                 cmd->error = -ETIMEDOUT;
 232                 return;
 233         }
 234         if (status & RSP_CRC_FAIL) {
 235                 cmd->error = -EIO;
 236                 return;
 237         }
 238         if (status & RSP_CRC_OK) {
 239                 if (cmd->flags & MMC_RSP_136) {
 240                         cmd->resp[3] = readl(host->base + REG_RESPONSE0);
 241                         cmd->resp[2] = readl(host->base + REG_RESPONSE1);
 242                         cmd->resp[1] = readl(host->base + REG_RESPONSE2);
 243                         cmd->resp[0] = readl(host->base + REG_RESPONSE3);
 244                 } else {
 245                         cmd->resp[0] = readl(host->base + REG_RESPONSE0);
 246                 }
 247         }
 248 }
 249
 250 static void moxart_dma_complete(void *param)
 251 {
 252         struct moxart_host *host = param;
 253
 254         complete(&host->dma_complete);
 255 }
 256
 257 static void moxart_transfer_dma(struct mmc_data *data, struct moxart_host *host)
 258 {
 259         u32 len, dir_data, dir_slave;
 260         unsigned long dma_time;
 261         struct dma_async_tx_descriptor *desc = NULL;
 262         struct dma_chan *dma_chan;
 263
 264         if (host->data_len == data->bytes_xfered)
 265                 return;
 266
 267         if (data->flags & MMC_DATA_WRITE) {
 268                 dma_chan = host->dma_chan_tx;
 269                 dir_data = DMA_TO_DEVICE;
 270                 dir_slave = DMA_MEM_TO_DEV;
 271         } else {
 272                 dma_chan = host->dma_chan_rx;
 273                 dir_data = DMA_FROM_DEVICE;
 274                 dir_slave = DMA_DEV_TO_MEM;
 275         }
 276
 277         len = dma_map_sg(dma_chan->device->dev, data->sg,
 278                          data->sg_len, dir_data);
 279
 280         if (len > 0) {
 281                 desc = dmaengine_prep_slave_sg(dma_chan, data->sg,
 282                                                len, dir_slave,
 283                                                DMA_PREP_INTERRUPT |
 284                                                DMA_CTRL_ACK);
 285         } else {
 286                 dev_err(mmc_dev(host->mmc), "dma_map_sg returned zero length\n");
 287         }
 288
 289         if (desc) {
 290                 host->tx_desc = desc;
 291                 desc->callback = moxart_dma_complete;
 292                 desc->callback_param = host;
 293                 dmaengine_submit(desc);
 294                 dma_async_issue_pending(dma_chan);
 295         }
 296
 297         data->bytes_xfered += host->data_remain;
 298
 299         dma_time = wait_for_completion_interruptible_timeout(
 300                    &host->dma_complete, host->timeout);
 301
 302         dma_unmap_sg(dma_chan->device->dev,
 303                      data->sg, data->sg_len,
 304                      dir_data);
 305 }
 306
 307
 308 static void moxart_transfer_pio(struct moxart_host *host)
 309 {
 310         struct mmc_data *data = host->mrq->cmd->data;
 311         u32 *sgp, len = 0, remain, status;
 312
 313         if (host->data_len == data->bytes_xfered)
 314                 return;
 315
 316         sgp = sg_virt(host->cur_sg);
 317         remain = host->data_remain;
 318
 319         if (data->flags & MMC_DATA_WRITE) {
 320                 while (remain > 0) {
 321                         if (moxart_wait_for_status(host, FIFO_URUN, &status)
 322                              == -ETIMEDOUT) {
 323                                 data->error = -ETIMEDOUT;
 324                                 complete(&host->pio_complete);
 325                                 return;
 326                         }
 327                         for (len = 0; len < remain && len < host->fifo_width;) {
 328                                 iowrite32(*sgp, host->base + REG_DATA_WINDOW);
 329                                 sgp++;
 330                                 len += 4;
 331                         }
 332                         remain -= len;
 333                 }
 334
 335         } else {
 336                 while (remain > 0) {
 337                         if (moxart_wait_for_status(host, FIFO_ORUN, &status)
 338                             == -ETIMEDOUT) {
 339                                 data->error = -ETIMEDOUT;
 340                                 complete(&host->pio_complete);
 341                                 return;
 342                         }
 343                         for (len = 0; len < remain && len < host->fifo_width;) {
 344                                 /* SCR data must be read in big endian. */
 345                                 if (data->mrq->cmd->opcode == SD_APP_SEND_SCR)
 346                                         *sgp = ioread32be(host->base +
 347                                                           REG_DATA_WINDOW);
 348                                 else
 349                                         *sgp = ioread32(host->base +
 350                                                         REG_DATA_WINDOW);
 351                                 sgp++;
 352                                 len += 4;
 353                         }
 354                         remain -= len;
 355                 }
 356         }
 357
 358         data->bytes_xfered += host->data_remain - remain;
 359         host->data_remain = remain;
 360
 361         if (host->data_len != data->bytes_xfered)
 362                 moxart_next_sg(host);
 363         else
 364                 complete(&host->pio_complete);
 365 }
 366
 367 static void moxart_prepare_data(struct moxart_host *host)
 368 {
 369         struct mmc_data *data = host->mrq->cmd->data;
 370         u32 datactrl;
 371         int blksz_bits;
 372
 373         if (!data)
 374                 return;
 375
 376         host->data_len = data->blocks * data->blksz;
 377         blksz_bits = ffs(data->blksz) - 1;
 378         BUG_ON(1 << blksz_bits != data->blksz);
 379
 380         moxart_init_sg(host, data);
 381
 382         datactrl = DCR_DATA_EN | (blksz_bits & DCR_BLK_SIZE);
 383
 384         if (data->flags & MMC_DATA_WRITE)
 385                 datactrl |= DCR_DATA_WRITE;
 386
 387         if ((host->data_len > host->fifo_width) && host->have_dma)
 388                 datactrl |= DCR_DMA_EN;
 389
 390         writel(DCR_DATA_FIFO_RESET, host->base + REG_DATA_CONTROL);
 391         writel(MASK_DATA | FIFO_URUN | FIFO_ORUN, host->base + REG_CLEAR);
 392         writel(host->rate, host->base + REG_DATA_TIMER);
 393         writel(host->data_len, host->base + REG_DATA_LENGTH);
 394         writel(datactrl, host->base + REG_DATA_CONTROL);
 395 }
 396
 397 static void moxart_request(struct mmc_host *mmc, struct mmc_request *mrq)
 398 {
 399         struct moxart_host *host = mmc_priv(mmc);
 400         unsigned long pio_time, flags;
 401         u32 status;
 402
 403         spin_lock_irqsave(&host->lock, flags);
 404
 405         init_completion(&host->dma_complete);
 406         init_completion(&host->pio_complete);
 407
 408         host->mrq = mrq;
 409
 410         if (readl(host->base + REG_STATUS) & CARD_DETECT) {
 411                 mrq->cmd->error = -ETIMEDOUT;
 412                 goto request_done;
 413         }
 414
 415         moxart_prepare_data(host);
 416         moxart_send_command(host, host->mrq->cmd);
 417
 418         if (mrq->cmd->data) {
 419                 if ((host->data_len > host->fifo_width) && host->have_dma) {
 420
 421                         writel(CARD_CHANGE, host->base + REG_INTERRUPT_MASK);
 422
 423                         spin_unlock_irqrestore(&host->lock, flags);
 424
 425                         moxart_transfer_dma(mrq->cmd->data, host);
 426
 427                         spin_lock_irqsave(&host->lock, flags);
 428                 } else {
 429
 430                         writel(MASK_INTR_PIO, host->base + REG_INTERRUPT_MASK);
 431
 432                         spin_unlock_irqrestore(&host->lock, flags);
 433
 434                         /* PIO transfers start from interrupt. */
 435                         pio_time = wait_for_completion_interruptible_timeout(
 436                                    &host->pio_complete, host->timeout);
 437
 438                         spin_lock_irqsave(&host->lock, flags);
 439                 }
 440
 441                 if (host->is_removed) {
 442                         dev_err(mmc_dev(host->mmc), "card removed\n");
 443                         mrq->cmd->error = -ETIMEDOUT;
 444                         goto request_done;
 445                 }
 446
 447                 if (moxart_wait_for_status(host, MASK_DATA, &status)
 448                     == -ETIMEDOUT) {
 449                         mrq->cmd->data->error = -ETIMEDOUT;
 450                         goto request_done;
 451                 }
 452
 453                 if (status & DATA_CRC_FAIL)
 454                         mrq->cmd->data->error = -ETIMEDOUT;
 455
 456                 if (mrq->cmd->data->stop)
 457                         moxart_send_command(host, mrq->cmd->data->stop);
 458         }
 459
 460 request_done:
 461         spin_unlock_irqrestore(&host->lock, flags);
 462         mmc_request_done(host->mmc, mrq);
 463 }
 464
 465 static irqreturn_t moxart_irq(int irq, void *devid)
 466 {
 467         struct moxart_host *host = (struct moxart_host *)devid;
 468         u32 status;
 469         unsigned long flags;
 470
 471         spin_lock_irqsave(&host->lock, flags);
 472
 473         status = readl(host->base + REG_STATUS);
 474         if (status & CARD_CHANGE) {
 475                 host->is_removed = status & CARD_DETECT;
 476                 if (host->is_removed && host->have_dma) {
 477                         dmaengine_terminate_all(host->dma_chan_tx);
 478                         dmaengine_terminate_all(host->dma_chan_rx);
 479                 }
 480                 host->mrq = NULL;
 481                 writel(MASK_INTR_PIO, host->base + REG_CLEAR);
 482                 writel(CARD_CHANGE, host->base + REG_INTERRUPT_MASK);
 483                 mmc_detect_change(host->mmc, 0);
 484         }
 485         if (status & (FIFO_ORUN | FIFO_URUN) && host->mrq)
 486                 moxart_transfer_pio(host);
 487
 488         spin_unlock_irqrestore(&host->lock, flags);
 489
 490         return IRQ_HANDLED;
 491 }
 492
 493 static void moxart_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 494 {
 495         struct moxart_host *host = mmc_priv(mmc);
 496         unsigned long flags;
 497         u8 power, div;
 498         u32 ctrl;
 499
 500         spin_lock_irqsave(&host->lock, flags);
 501
 502         if (ios->clock) {
 503                 for (div = 0; div < CLK_DIV_MASK; ++div) {
 504                         if (ios->clock >= host->sysclk / (2 * (div + 1)))
 505                                 break;
 506                 }
 507                 ctrl = CLK_SD | div;
 508                 host->rate = host->sysclk / (2 * (div + 1));
 509                 if (host->rate > host->sysclk)
 510                         ctrl |= CLK_HISPD;
 511                 writel(ctrl, host->base + REG_CLOCK_CONTROL);
 512         }
 513
 514         if (ios->power_mode == MMC_POWER_OFF) {
 515                 writel(readl(host->base + REG_POWER_CONTROL) & ~SD_POWER_ON,
 516                        host->base + REG_POWER_CONTROL);
 517         } else {
 518                 if (ios->vdd < MIN_POWER)
 519                         power = 0;
 520                 else
 521                         power = ios->vdd - MIN_POWER;
 522
 523                 writel(SD_POWER_ON | (u32) power,
 524                        host->base + REG_POWER_CONTROL);
 525         }
 526
 527         switch (ios->bus_width) {
 528         case MMC_BUS_WIDTH_4:
 529                 writel(BUS_WIDTH_4, host->base + REG_BUS_WIDTH);
 530                 break;
 531         case MMC_BUS_WIDTH_8:
 532                 writel(BUS_WIDTH_8, host->base + REG_BUS_WIDTH);
 533                 break;
 534         default:
 535                 writel(BUS_WIDTH_1, host->base + REG_BUS_WIDTH);
 536                 break;
 537         }
 538
 539         spin_unlock_irqrestore(&host->lock, flags);
 540 }
 541
 542
 543 static int moxart_get_ro(struct mmc_host *mmc)
 544 {
 545         struct moxart_host *host = mmc_priv(mmc);
 546
 547         return !!(readl(host->base + REG_STATUS) & WRITE_PROT);
 548 }
 549
 550 static struct mmc_host_ops moxart_ops = {
 551         .request = moxart_request,
 552         .set_ios = moxart_set_ios,
 553         .get_ro = moxart_get_ro,
 554 };
 555
 556 static int moxart_probe(struct platform_device *pdev)
 557 {
 558         struct device *dev = &pdev->dev;
 559         struct device_node *node = dev->of_node;
 560         struct resource res_mmc;
 561         struct mmc_host *mmc;
 562         struct moxart_host *host = NULL;
 563         struct dma_slave_config cfg;
 564         struct clk *clk;
 565         void __iomem *reg_mmc;
 566         int irq, ret;
 567         u32 i;
 568
 569         mmc = mmc_alloc_host(sizeof(struct moxart_host), dev);
 570         if (!mmc) {
 571                 dev_err(dev, "mmc_alloc_host failed\n");
 572                 ret = -ENOMEM;
 573                 goto out;
 574         }
 575
 576         ret = of_address_to_resource(node, 0, &res_mmc);
 577         if (ret) {
 578                 dev_err(dev, "of_address_to_resource failed\n");
 579                 goto out;
 580         }
 581
 582         irq = irq_of_parse_and_map(node, 0);
 583         if (irq <= 0) {
 584                 dev_err(dev, "irq_of_parse_and_map failed\n");
 585                 ret = -EINVAL;
 586                 goto out;
 587         }
 588
 589         clk = devm_clk_get(dev, NULL);
 590         if (IS_ERR(clk)) {
 591                 ret = PTR_ERR(clk);
 592                 goto out;
 593         }
 594
 595         reg_mmc = devm_ioremap_resource(dev, &res_mmc);
 596         if (IS_ERR(reg_mmc)) {
 597                 ret = PTR_ERR(reg_mmc);
 598                 goto out;
 599         }
 600
 601         ret = mmc_of_parse(mmc);
 602         if (ret)
 603                 goto out;
 604
 605         host = mmc_priv(mmc);
 606         host->mmc = mmc;
 607         host->base = reg_mmc;
 608         host->reg_phys = res_mmc.start;
 609         host->timeout = msecs_to_jiffies(1000);
 610         host->sysclk = clk_get_rate(clk);
 611         host->fifo_width = readl(host->base + REG_FEATURE) << 2;
 612         host->dma_chan_tx = dma_request_slave_channel_reason(dev, "tx");
 613         host->dma_chan_rx = dma_request_slave_channel_reason(dev, "rx");
 614
 615         spin_lock_init(&host->lock);
 616
 617         mmc->ops = &moxart_ops;
 618         mmc->f_max = DIV_ROUND_CLOSEST(host->sysclk, 2);
 619         mmc->f_min = DIV_ROUND_CLOSEST(host->sysclk, CLK_DIV_MASK * 2);
 620         mmc->ocr_avail = 0xffff00;      /* Support 2.0v - 3.6v power. */
 621
 622         if (IS_ERR(host->dma_chan_tx) || IS_ERR(host->dma_chan_rx)) {
 623                 if (PTR_ERR(host->dma_chan_tx) == -EPROBE_DEFER ||
 624                     PTR_ERR(host->dma_chan_rx) == -EPROBE_DEFER) {
 625                         ret = -EPROBE_DEFER;
 626                         goto out;
 627                 }
 628                 dev_dbg(dev, "PIO mode transfer enabled\n");
 629                 host->have_dma = false;
 630         } else {
 631                 dev_dbg(dev, "DMA channels found (%p,%p)\n",
 632                          host->dma_chan_tx, host->dma_chan_rx);
 633                 host->have_dma = true;
 634
 635                 cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
 636                 cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
 637
 638                 cfg.direction = DMA_MEM_TO_DEV;
 639                 cfg.src_addr = 0;
 640                 cfg.dst_addr = host->reg_phys + REG_DATA_WINDOW;
 641                 dmaengine_slave_config(host->dma_chan_tx, &cfg);
 642
 643                 cfg.direction = DMA_DEV_TO_MEM;
 644                 cfg.src_addr = host->reg_phys + REG_DATA_WINDOW;
 645                 cfg.dst_addr = 0;
 646                 dmaengine_slave_config(host->dma_chan_rx, &cfg);
 647         }
 648
 649         switch ((readl(host->base + REG_BUS_WIDTH) >> 3) & 3) {
 650         case 1:
 651                 mmc->caps |= MMC_CAP_4_BIT_DATA;
 652                 break;
 653         case 2:
 654                 mmc->caps |= MMC_CAP_4_BIT_DATA | MMC_CAP_8_BIT_DATA;
 655                 break;
 656         default:
 657                 break;
 658         }
 659
 660         writel(0, host->base + REG_INTERRUPT_MASK);
 661
 662         writel(CMD_SDC_RESET, host->base + REG_COMMAND);
 663         for (i = 0; i < MAX_RETRIES; i++) {
 664                 if (!(readl(host->base + REG_COMMAND) & CMD_SDC_RESET))
 665                         break;
 666                 udelay(5);
 667         }
 668
 669         ret = devm_request_irq(dev, irq, moxart_irq, 0, "moxart-mmc", host);
 670         if (ret)
 671                 goto out;
 672
 673         dev_set_drvdata(dev, mmc);
 674         mmc_add_host(mmc);
 675
 676         dev_dbg(dev, "IRQ=%d, FIFO is %d bytes\n", irq, host->fifo_width);
 677
 678         return 0;
 679
 680 out:
 681         if (mmc)
 682                 mmc_free_host(mmc);
 683         return ret;
 684 }
 685
 686 static int moxart_remove(struct platform_device *pdev)
 687 {
 688         struct mmc_host *mmc = dev_get_drvdata(&pdev->dev);
 689         struct moxart_host *host = mmc_priv(mmc);
 690
 691         dev_set_drvdata(&pdev->dev, NULL);
 692
 693         if (mmc) {
 694                 if (!IS_ERR(host->dma_chan_tx))
 695                         dma_release_channel(host->dma_chan_tx);
 696                 if (!IS_ERR(host->dma_chan_rx))
 697                         dma_release_channel(host->dma_chan_rx);
 698                 mmc_remove_host(mmc);
 699                 mmc_free_host(mmc);
 700
 701                 writel(0, host->base + REG_INTERRUPT_MASK);
 702                 writel(0, host->base + REG_POWER_CONTROL);
 703                 writel(readl(host->base + REG_CLOCK_CONTROL) | CLK_OFF,
 704                        host->base + REG_CLOCK_CONTROL);
 705         }
 706         return 0;
 707 }
 708
 709 static const struct of_device_id moxart_mmc_match[] = {
 710         { .compatible = "moxa,moxart-mmc" },
 711         { .compatible = "faraday,ftsdc010" },
 712         { }
 713 };
 714 MODULE_DEVICE_TABLE(of, moxart_mmc_match);
 715
 716 static struct platform_driver moxart_mmc_driver = {
 717         .probe      = moxart_probe,
 718         .remove     = moxart_remove,
 719         .driver     = {
 720                 .name           = "mmc-moxart",
 721                 .of_match_table = moxart_mmc_match,
 722         },
 723 };
 724 module_platform_driver(moxart_mmc_driver);
 725
 726 MODULE_ALIAS("platform:mmc-moxart");
 727 MODULE_DESCRIPTION("MOXA ART MMC driver");
 728 MODULE_LICENSE("GPL v2");
 729 MODULE_AUTHOR("Jonas Jensen <jonas.jensen@gmail.com>");