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_4_SUPPORT     BIT(3)
 115 #define BUS_WIDTH_4             BIT(2)
 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_slave;
 260         struct dma_async_tx_descriptor *desc = NULL;
 261         struct dma_chan *dma_chan;
 262
 263         if (host->data_len == data->bytes_xfered)
 264                 return;
 265
 266         if (data->flags & MMC_DATA_WRITE) {
 267                 dma_chan = host->dma_chan_tx;
 268                 dir_slave = DMA_MEM_TO_DEV;
 269         } else {
 270                 dma_chan = host->dma_chan_rx;
 271                 dir_slave = DMA_DEV_TO_MEM;
 272         }
 273
 274         len = dma_map_sg(dma_chan->device->dev, data->sg,
 275                          data->sg_len, mmc_get_dma_dir(data));
 276
 277         if (len > 0) {
 278                 desc = dmaengine_prep_slave_sg(dma_chan, data->sg,
 279                                                len, dir_slave,
 280                                                DMA_PREP_INTERRUPT |
 281                                                DMA_CTRL_ACK);
 282         } else {
 283                 dev_err(mmc_dev(host->mmc), "dma_map_sg returned zero length\n");
 284         }
 285
 286         if (desc) {
 287                 host->tx_desc = desc;
 288                 desc->callback = moxart_dma_complete;
 289                 desc->callback_param = host;
 290                 dmaengine_submit(desc);
 291                 dma_async_issue_pending(dma_chan);
 292         }
 293
 294         data->bytes_xfered += host->data_remain;
 295
 296         wait_for_completion_interruptible_timeout(&host->dma_complete,
 297                                                   host->timeout);
 298
 299         dma_unmap_sg(dma_chan->device->dev,
 300                      data->sg, data->sg_len,
 301                      mmc_get_dma_dir(data));
 302 }
 303
 304
 305 static void moxart_transfer_pio(struct moxart_host *host)
 306 {
 307         struct mmc_data *data = host->mrq->cmd->data;
 308         u32 *sgp, len = 0, remain, status;
 309
 310         if (host->data_len == data->bytes_xfered)
 311                 return;
 312
 313         sgp = sg_virt(host->cur_sg);
 314         remain = host->data_remain;
 315
 316         if (data->flags & MMC_DATA_WRITE) {
 317                 while (remain > 0) {
 318                         if (moxart_wait_for_status(host, FIFO_URUN, &status)
 319                              == -ETIMEDOUT) {
 320                                 data->error = -ETIMEDOUT;
 321                                 complete(&host->pio_complete);
 322                                 return;
 323                         }
 324                         for (len = 0; len < remain && len < host->fifo_width;) {
 325                                 iowrite32(*sgp, host->base + REG_DATA_WINDOW);
 326                                 sgp++;
 327                                 len += 4;
 328                         }
 329                         remain -= len;
 330                 }
 331
 332         } else {
 333                 while (remain > 0) {
 334                         if (moxart_wait_for_status(host, FIFO_ORUN, &status)
 335                             == -ETIMEDOUT) {
 336                                 data->error = -ETIMEDOUT;
 337                                 complete(&host->pio_complete);
 338                                 return;
 339                         }
 340                         for (len = 0; len < remain && len < host->fifo_width;) {
 341                                 *sgp = ioread32(host->base + REG_DATA_WINDOW);
 342                                 sgp++;
 343                                 len += 4;
 344                         }
 345                         remain -= len;
 346                 }
 347         }
 348
 349         data->bytes_xfered += host->data_remain - remain;
 350         host->data_remain = remain;
 351
 352         if (host->data_len != data->bytes_xfered)
 353                 moxart_next_sg(host);
 354         else
 355                 complete(&host->pio_complete);
 356 }
 357
 358 static void moxart_prepare_data(struct moxart_host *host)
 359 {
 360         struct mmc_data *data = host->mrq->cmd->data;
 361         u32 datactrl;
 362         int blksz_bits;
 363
 364         if (!data)
 365                 return;
 366
 367         host->data_len = data->blocks * data->blksz;
 368         blksz_bits = ffs(data->blksz) - 1;
 369         BUG_ON(1 << blksz_bits != data->blksz);
 370
 371         moxart_init_sg(host, data);
 372
 373         datactrl = DCR_DATA_EN | (blksz_bits & DCR_BLK_SIZE);
 374
 375         if (data->flags & MMC_DATA_WRITE)
 376                 datactrl |= DCR_DATA_WRITE;
 377
 378         if ((host->data_len > host->fifo_width) && host->have_dma)
 379                 datactrl |= DCR_DMA_EN;
 380
 381         writel(DCR_DATA_FIFO_RESET, host->base + REG_DATA_CONTROL);
 382         writel(MASK_DATA | FIFO_URUN | FIFO_ORUN, host->base + REG_CLEAR);
 383         writel(host->rate, host->base + REG_DATA_TIMER);
 384         writel(host->data_len, host->base + REG_DATA_LENGTH);
 385         writel(datactrl, host->base + REG_DATA_CONTROL);
 386 }
 387
 388 static void moxart_request(struct mmc_host *mmc, struct mmc_request *mrq)
 389 {
 390         struct moxart_host *host = mmc_priv(mmc);
 391         unsigned long flags;
 392         u32 status;
 393
 394         spin_lock_irqsave(&host->lock, flags);
 395
 396         init_completion(&host->dma_complete);
 397         init_completion(&host->pio_complete);
 398
 399         host->mrq = mrq;
 400
 401         if (readl(host->base + REG_STATUS) & CARD_DETECT) {
 402                 mrq->cmd->error = -ETIMEDOUT;
 403                 goto request_done;
 404         }
 405
 406         moxart_prepare_data(host);
 407         moxart_send_command(host, host->mrq->cmd);
 408
 409         if (mrq->cmd->data) {
 410                 if ((host->data_len > host->fifo_width) && host->have_dma) {
 411
 412                         writel(CARD_CHANGE, host->base + REG_INTERRUPT_MASK);
 413
 414                         spin_unlock_irqrestore(&host->lock, flags);
 415
 416                         moxart_transfer_dma(mrq->cmd->data, host);
 417
 418                         spin_lock_irqsave(&host->lock, flags);
 419                 } else {
 420
 421                         writel(MASK_INTR_PIO, host->base + REG_INTERRUPT_MASK);
 422
 423                         spin_unlock_irqrestore(&host->lock, flags);
 424
 425                         /* PIO transfers start from interrupt. */
 426                         wait_for_completion_interruptible_timeout(&host->pio_complete,
 427                                                                   host->timeout);
 428
 429                         spin_lock_irqsave(&host->lock, flags);
 430                 }
 431
 432                 if (host->is_removed) {
 433                         dev_err(mmc_dev(host->mmc), "card removed\n");
 434                         mrq->cmd->error = -ETIMEDOUT;
 435                         goto request_done;
 436                 }
 437
 438                 if (moxart_wait_for_status(host, MASK_DATA, &status)
 439                     == -ETIMEDOUT) {
 440                         mrq->cmd->data->error = -ETIMEDOUT;
 441                         goto request_done;
 442                 }
 443
 444                 if (status & DATA_CRC_FAIL)
 445                         mrq->cmd->data->error = -ETIMEDOUT;
 446
 447                 if (mrq->cmd->data->stop)
 448                         moxart_send_command(host, mrq->cmd->data->stop);
 449         }
 450
 451 request_done:
 452         spin_unlock_irqrestore(&host->lock, flags);
 453         mmc_request_done(host->mmc, mrq);
 454 }
 455
 456 static irqreturn_t moxart_irq(int irq, void *devid)
 457 {
 458         struct moxart_host *host = (struct moxart_host *)devid;
 459         u32 status;
 460
 461         spin_lock(&host->lock);
 462
 463         status = readl(host->base + REG_STATUS);
 464         if (status & CARD_CHANGE) {
 465                 host->is_removed = status & CARD_DETECT;
 466                 if (host->is_removed && host->have_dma) {
 467                         dmaengine_terminate_all(host->dma_chan_tx);
 468                         dmaengine_terminate_all(host->dma_chan_rx);
 469                 }
 470                 host->mrq = NULL;
 471                 writel(MASK_INTR_PIO, host->base + REG_CLEAR);
 472                 writel(CARD_CHANGE, host->base + REG_INTERRUPT_MASK);
 473                 mmc_detect_change(host->mmc, 0);
 474         }
 475         if (status & (FIFO_ORUN | FIFO_URUN) && host->mrq)
 476                 moxart_transfer_pio(host);
 477
 478         spin_unlock(&host->lock);
 479
 480         return IRQ_HANDLED;
 481 }
 482
 483 static void moxart_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 484 {
 485         struct moxart_host *host = mmc_priv(mmc);
 486         unsigned long flags;
 487         u8 power, div;
 488         u32 ctrl;
 489
 490         spin_lock_irqsave(&host->lock, flags);
 491
 492         if (ios->clock) {
 493                 for (div = 0; div < CLK_DIV_MASK; ++div) {
 494                         if (ios->clock >= host->sysclk / (2 * (div + 1)))
 495                                 break;
 496                 }
 497                 ctrl = CLK_SD | div;
 498                 host->rate = host->sysclk / (2 * (div + 1));
 499                 if (host->rate > host->sysclk)
 500                         ctrl |= CLK_HISPD;
 501                 writel(ctrl, host->base + REG_CLOCK_CONTROL);
 502         }
 503
 504         if (ios->power_mode == MMC_POWER_OFF) {
 505                 writel(readl(host->base + REG_POWER_CONTROL) & ~SD_POWER_ON,
 506                        host->base + REG_POWER_CONTROL);
 507         } else {
 508                 if (ios->vdd < MIN_POWER)
 509                         power = 0;
 510                 else
 511                         power = ios->vdd - MIN_POWER;
 512
 513                 writel(SD_POWER_ON | (u32) power,
 514                        host->base + REG_POWER_CONTROL);
 515         }
 516
 517         switch (ios->bus_width) {
 518         case MMC_BUS_WIDTH_4:
 519                 writel(BUS_WIDTH_4, host->base + REG_BUS_WIDTH);
 520                 break;
 521         default:
 522                 writel(BUS_WIDTH_1, host->base + REG_BUS_WIDTH);
 523                 break;
 524         }
 525
 526         spin_unlock_irqrestore(&host->lock, flags);
 527 }
 528
 529
 530 static int moxart_get_ro(struct mmc_host *mmc)
 531 {
 532         struct moxart_host *host = mmc_priv(mmc);
 533
 534         return !!(readl(host->base + REG_STATUS) & WRITE_PROT);
 535 }
 536
 537 static const struct mmc_host_ops moxart_ops = {
 538         .request = moxart_request,
 539         .set_ios = moxart_set_ios,
 540         .get_ro = moxart_get_ro,
 541 };
 542
 543 static int moxart_probe(struct platform_device *pdev)
 544 {
 545         struct device *dev = &pdev->dev;
 546         struct device_node *node = dev->of_node;
 547         struct resource res_mmc;
 548         struct mmc_host *mmc;
 549         struct moxart_host *host = NULL;
 550         struct dma_slave_config cfg;
 551         struct clk *clk;
 552         void __iomem *reg_mmc;
 553         int irq, ret;
 554         u32 i;
 555
 556         mmc = mmc_alloc_host(sizeof(struct moxart_host), dev);
 557         if (!mmc) {
 558                 dev_err(dev, "mmc_alloc_host failed\n");
 559                 ret = -ENOMEM;
 560                 goto out_mmc;
 561         }
 562
 563         ret = of_address_to_resource(node, 0, &res_mmc);
 564         if (ret) {
 565                 dev_err(dev, "of_address_to_resource failed\n");
 566                 goto out_mmc;
 567         }
 568
 569         irq = irq_of_parse_and_map(node, 0);
 570         if (irq <= 0) {
 571                 dev_err(dev, "irq_of_parse_and_map failed\n");
 572                 ret = -EINVAL;
 573                 goto out_mmc;
 574         }
 575
 576         clk = devm_clk_get(dev, NULL);
 577         if (IS_ERR(clk)) {
 578                 ret = PTR_ERR(clk);
 579                 goto out_mmc;
 580         }
 581
 582         reg_mmc = devm_ioremap_resource(dev, &res_mmc);
 583         if (IS_ERR(reg_mmc)) {
 584                 ret = PTR_ERR(reg_mmc);
 585                 goto out_mmc;
 586         }
 587
 588         ret = mmc_of_parse(mmc);
 589         if (ret)
 590                 goto out_mmc;
 591
 592         host = mmc_priv(mmc);
 593         host->mmc = mmc;
 594         host->base = reg_mmc;
 595         host->reg_phys = res_mmc.start;
 596         host->timeout = msecs_to_jiffies(1000);
 597         host->sysclk = clk_get_rate(clk);
 598         host->fifo_width = readl(host->base + REG_FEATURE) << 2;
 599         host->dma_chan_tx = dma_request_chan(dev, "tx");
 600         host->dma_chan_rx = dma_request_chan(dev, "rx");
 601
 602         spin_lock_init(&host->lock);
 603
 604         mmc->ops = &moxart_ops;
 605         mmc->f_max = DIV_ROUND_CLOSEST(host->sysclk, 2);
 606         mmc->f_min = DIV_ROUND_CLOSEST(host->sysclk, CLK_DIV_MASK * 2);
 607         mmc->ocr_avail = 0xffff00;      /* Support 2.0v - 3.6v power. */
 608         mmc->max_blk_size = 2048; /* Max. block length in REG_DATA_CONTROL */
 609         mmc->max_req_size = DATA_LEN_MASK; /* bits 0-23 in REG_DATA_LENGTH */
 610         mmc->max_blk_count = mmc->max_req_size / 512;
 611
 612         if (IS_ERR(host->dma_chan_tx) || IS_ERR(host->dma_chan_rx)) {
 613                 if (PTR_ERR(host->dma_chan_tx) == -EPROBE_DEFER ||
 614                     PTR_ERR(host->dma_chan_rx) == -EPROBE_DEFER) {
 615                         ret = -EPROBE_DEFER;
 616                         goto out;
 617                 }
 618                 if (!IS_ERR(host->dma_chan_tx)) {
 619                         dma_release_channel(host->dma_chan_tx);
 620                         host->dma_chan_tx = NULL;
 621                 }
 622                 if (!IS_ERR(host->dma_chan_rx)) {
 623                         dma_release_channel(host->dma_chan_rx);
 624                         host->dma_chan_rx = NULL;
 625                 }
 626                 dev_dbg(dev, "PIO mode transfer enabled\n");
 627                 host->have_dma = false;
 628
 629                 mmc->max_seg_size = mmc->max_req_size;
 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                 memset(&cfg, 0, sizeof(cfg));
 636                 cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
 637                 cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
 638
 639                 cfg.direction = DMA_MEM_TO_DEV;
 640                 cfg.src_addr = 0;
 641                 cfg.dst_addr = host->reg_phys + REG_DATA_WINDOW;
 642                 dmaengine_slave_config(host->dma_chan_tx, &cfg);
 643
 644                 cfg.direction = DMA_DEV_TO_MEM;
 645                 cfg.src_addr = host->reg_phys + REG_DATA_WINDOW;
 646                 cfg.dst_addr = 0;
 647                 dmaengine_slave_config(host->dma_chan_rx, &cfg);
 648
 649                 mmc->max_seg_size = min3(mmc->max_req_size,
 650                         dma_get_max_seg_size(host->dma_chan_rx->device->dev),
 651                         dma_get_max_seg_size(host->dma_chan_tx->device->dev));
 652         }
 653
 654         if (readl(host->base + REG_BUS_WIDTH) & BUS_WIDTH_4_SUPPORT)
 655                 mmc->caps |= MMC_CAP_4_BIT_DATA;
 656
 657         writel(0, host->base + REG_INTERRUPT_MASK);
 658
 659         writel(CMD_SDC_RESET, host->base + REG_COMMAND);
 660         for (i = 0; i < MAX_RETRIES; i++) {
 661                 if (!(readl(host->base + REG_COMMAND) & CMD_SDC_RESET))
 662                         break;
 663                 udelay(5);
 664         }
 665
 666         ret = devm_request_irq(dev, irq, moxart_irq, 0, "moxart-mmc", host);
 667         if (ret)
 668                 goto out;
 669
 670         dev_set_drvdata(dev, mmc);
 671         ret = mmc_add_host(mmc);
 672         if (ret)
 673                 goto out;
 674
 675         dev_dbg(dev, "IRQ=%d, FIFO is %d bytes\n", irq, host->fifo_width);
 676
 677         return 0;
 678
 679 out:
 680         if (!IS_ERR_OR_NULL(host->dma_chan_tx))
 681                 dma_release_channel(host->dma_chan_tx);
 682         if (!IS_ERR_OR_NULL(host->dma_chan_rx))
 683                 dma_release_channel(host->dma_chan_rx);
 684 out_mmc:
 685         if (mmc)
 686                 mmc_free_host(mmc);
 687         return ret;
 688 }
 689
 690 static void moxart_remove(struct platform_device *pdev)
 691 {
 692         struct mmc_host *mmc = dev_get_drvdata(&pdev->dev);
 693         struct moxart_host *host = mmc_priv(mmc);
 694
 695         if (!IS_ERR_OR_NULL(host->dma_chan_tx))
 696                 dma_release_channel(host->dma_chan_tx);
 697         if (!IS_ERR_OR_NULL(host->dma_chan_rx))
 698                 dma_release_channel(host->dma_chan_rx);
 699         mmc_remove_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         mmc_free_host(mmc);
 706 }
 707
 708 static const struct of_device_id moxart_mmc_match[] = {
 709         { .compatible = "moxa,moxart-mmc" },
 710         { .compatible = "faraday,ftsdc010" },
 711         { }
 712 };
 713 MODULE_DEVICE_TABLE(of, moxart_mmc_match);
 714
 715 static struct platform_driver moxart_mmc_driver = {
 716         .probe      = moxart_probe,
 717         .remove_new = moxart_remove,
 718         .driver     = {
 719                 .name           = "mmc-moxart",
 720                 .probe_type     = PROBE_PREFER_ASYNCHRONOUS,
 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>");