drivers/spi/spi-dw-dma.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Special handling for DW DMA core
   4  *
   5  * Copyright (c) 2009, 2014 Intel Corporation.
   6  */
   7
   8 #include <linux/completion.h>
   9 #include <linux/dma-mapping.h>
  10 #include <linux/dmaengine.h>
  11 #include <linux/irqreturn.h>
  12 #include <linux/jiffies.h>
  13 #include <linux/pci.h>
  14 #include <linux/platform_data/dma-dw.h>
  15 #include <linux/spi/spi.h>
  16 #include <linux/types.h>
  17
  18 #include "spi-dw.h"
  19
  20 #define RX_BUSY         0
  21 #define RX_BURST_LEVEL  16
  22 #define TX_BUSY         1
  23 #define TX_BURST_LEVEL  16
  24
  25 static bool dw_spi_dma_chan_filter(struct dma_chan *chan, void *param)
  26 {
  27         struct dw_dma_slave *s = param;
  28
  29         if (s->dma_dev != chan->device->dev)
  30                 return false;
  31
  32         chan->private = s;
  33         return true;
  34 }
  35
  36 static void dw_spi_dma_maxburst_init(struct dw_spi *dws)
  37 {
  38         struct dma_slave_caps caps;
  39         u32 max_burst, def_burst;
  40         int ret;
  41
  42         def_burst = dws->fifo_len / 2;
  43
  44         ret = dma_get_slave_caps(dws->rxchan, &caps);
  45         if (!ret && caps.max_burst)
  46                 max_burst = caps.max_burst;
  47         else
  48                 max_burst = RX_BURST_LEVEL;
  49
  50         dws->rxburst = min(max_burst, def_burst);
  51         dw_writel(dws, DW_SPI_DMARDLR, dws->rxburst - 1);
  52
  53         ret = dma_get_slave_caps(dws->txchan, &caps);
  54         if (!ret && caps.max_burst)
  55                 max_burst = caps.max_burst;
  56         else
  57                 max_burst = TX_BURST_LEVEL;
  58
  59         /*
  60          * Having a Rx DMA channel serviced with higher priority than a Tx DMA
  61          * channel might not be enough to provide a well balanced DMA-based
  62          * SPI transfer interface. There might still be moments when the Tx DMA
  63          * channel is occasionally handled faster than the Rx DMA channel.
  64          * That in its turn will eventually cause the SPI Rx FIFO overflow if
  65          * SPI bus speed is high enough to fill the SPI Rx FIFO in before it's
  66          * cleared by the Rx DMA channel. In order to fix the problem the Tx
  67          * DMA activity is intentionally slowed down by limiting the SPI Tx
  68          * FIFO depth with a value twice bigger than the Tx burst length.
  69          */
  70         dws->txburst = min(max_burst, def_burst);
  71         dw_writel(dws, DW_SPI_DMATDLR, dws->txburst);
  72 }
  73
  74 static void dw_spi_dma_sg_burst_init(struct dw_spi *dws)
  75 {
  76         struct dma_slave_caps tx = {0}, rx = {0};
  77
  78         dma_get_slave_caps(dws->txchan, &tx);
  79         dma_get_slave_caps(dws->rxchan, &rx);
  80
  81         if (tx.max_sg_burst > 0 && rx.max_sg_burst > 0)
  82                 dws->dma_sg_burst = min(tx.max_sg_burst, rx.max_sg_burst);
  83         else if (tx.max_sg_burst > 0)
  84                 dws->dma_sg_burst = tx.max_sg_burst;
  85         else if (rx.max_sg_burst > 0)
  86                 dws->dma_sg_burst = rx.max_sg_burst;
  87         else
  88                 dws->dma_sg_burst = 0;
  89 }
  90
  91 static int dw_spi_dma_init_mfld(struct device *dev, struct dw_spi *dws)
  92 {
  93         struct dw_dma_slave dma_tx = { .dst_id = 1 }, *tx = &dma_tx;
  94         struct dw_dma_slave dma_rx = { .src_id = 0 }, *rx = &dma_rx;
  95         struct pci_dev *dma_dev;
  96         dma_cap_mask_t mask;
  97
  98         /*
  99          * Get pci device for DMA controller, currently it could only
 100          * be the DMA controller of Medfield
 101          */
 102         dma_dev = pci_get_device(PCI_VENDOR_ID_INTEL, 0x0827, NULL);
 103         if (!dma_dev)
 104                 return -ENODEV;
 105
 106         dma_cap_zero(mask);
 107         dma_cap_set(DMA_SLAVE, mask);
 108
 109         /* 1. Init rx channel */
 110         rx->dma_dev = &dma_dev->dev;
 111         dws->rxchan = dma_request_channel(mask, dw_spi_dma_chan_filter, rx);
 112         if (!dws->rxchan)
 113                 goto err_exit;
 114
 115         /* 2. Init tx channel */
 116         tx->dma_dev = &dma_dev->dev;
 117         dws->txchan = dma_request_channel(mask, dw_spi_dma_chan_filter, tx);
 118         if (!dws->txchan)
 119                 goto free_rxchan;
 120
 121         dws->master->dma_rx = dws->rxchan;
 122         dws->master->dma_tx = dws->txchan;
 123
 124         init_completion(&dws->dma_completion);
 125
 126         dw_spi_dma_maxburst_init(dws);
 127
 128         dw_spi_dma_sg_burst_init(dws);
 129
 130         return 0;
 131
 132 free_rxchan:
 133         dma_release_channel(dws->rxchan);
 134         dws->rxchan = NULL;
 135 err_exit:
 136         return -EBUSY;
 137 }
 138
 139 static int dw_spi_dma_init_generic(struct device *dev, struct dw_spi *dws)
 140 {
 141         dws->rxchan = dma_request_slave_channel(dev, "rx");
 142         if (!dws->rxchan)
 143                 return -ENODEV;
 144
 145         dws->txchan = dma_request_slave_channel(dev, "tx");
 146         if (!dws->txchan) {
 147                 dma_release_channel(dws->rxchan);
 148                 dws->rxchan = NULL;
 149                 return -ENODEV;
 150         }
 151
 152         dws->master->dma_rx = dws->rxchan;
 153         dws->master->dma_tx = dws->txchan;
 154
 155         init_completion(&dws->dma_completion);
 156
 157         dw_spi_dma_maxburst_init(dws);
 158
 159         dw_spi_dma_sg_burst_init(dws);
 160
 161         return 0;
 162 }
 163
 164 static void dw_spi_dma_exit(struct dw_spi *dws)
 165 {
 166         if (dws->txchan) {
 167                 dmaengine_terminate_sync(dws->txchan);
 168                 dma_release_channel(dws->txchan);
 169         }
 170
 171         if (dws->rxchan) {
 172                 dmaengine_terminate_sync(dws->rxchan);
 173                 dma_release_channel(dws->rxchan);
 174         }
 175 }
 176
 177 static irqreturn_t dw_spi_dma_transfer_handler(struct dw_spi *dws)
 178 {
 179         dw_spi_check_status(dws, false);
 180
 181         complete(&dws->dma_completion);
 182
 183         return IRQ_HANDLED;
 184 }
 185
 186 static bool dw_spi_can_dma(struct spi_controller *master,
 187                            struct spi_device *spi, struct spi_transfer *xfer)
 188 {
 189         struct dw_spi *dws = spi_controller_get_devdata(master);
 190
 191         return xfer->len > dws->fifo_len;
 192 }
 193
 194 static enum dma_slave_buswidth dw_spi_dma_convert_width(u8 n_bytes)
 195 {
 196         if (n_bytes == 1)
 197                 return DMA_SLAVE_BUSWIDTH_1_BYTE;
 198         else if (n_bytes == 2)
 199                 return DMA_SLAVE_BUSWIDTH_2_BYTES;
 200
 201         return DMA_SLAVE_BUSWIDTH_UNDEFINED;
 202 }
 203
 204 static int dw_spi_dma_wait(struct dw_spi *dws, unsigned int len, u32 speed)
 205 {
 206         unsigned long long ms;
 207
 208         ms = len * MSEC_PER_SEC * BITS_PER_BYTE;
 209         do_div(ms, speed);
 210         ms += ms + 200;
 211
 212         if (ms > UINT_MAX)
 213                 ms = UINT_MAX;
 214
 215         ms = wait_for_completion_timeout(&dws->dma_completion,
 216                                          msecs_to_jiffies(ms));
 217
 218         if (ms == 0) {
 219                 dev_err(&dws->master->cur_msg->spi->dev,
 220                         "DMA transaction timed out\n");
 221                 return -ETIMEDOUT;
 222         }
 223
 224         return 0;
 225 }
 226
 227 static inline bool dw_spi_dma_tx_busy(struct dw_spi *dws)
 228 {
 229         return !(dw_readl(dws, DW_SPI_SR) & SR_TF_EMPT);
 230 }
 231
 232 static int dw_spi_dma_wait_tx_done(struct dw_spi *dws,
 233                                    struct spi_transfer *xfer)
 234 {
 235         int retry = SPI_WAIT_RETRIES;
 236         struct spi_delay delay;
 237         u32 nents;
 238
 239         nents = dw_readl(dws, DW_SPI_TXFLR);
 240         delay.unit = SPI_DELAY_UNIT_SCK;
 241         delay.value = nents * dws->n_bytes * BITS_PER_BYTE;
 242
 243         while (dw_spi_dma_tx_busy(dws) && retry--)
 244                 spi_delay_exec(&delay, xfer);
 245
 246         if (retry < 0) {
 247                 dev_err(&dws->master->dev, "Tx hanged up\n");
 248                 return -EIO;
 249         }
 250
 251         return 0;
 252 }
 253
 254 /*
 255  * dws->dma_chan_busy is set before the dma transfer starts, callback for tx
 256  * channel will clear a corresponding bit.
 257  */
 258 static void dw_spi_dma_tx_done(void *arg)
 259 {
 260         struct dw_spi *dws = arg;
 261
 262         clear_bit(TX_BUSY, &dws->dma_chan_busy);
 263         if (test_bit(RX_BUSY, &dws->dma_chan_busy))
 264                 return;
 265
 266         complete(&dws->dma_completion);
 267 }
 268
 269 static int dw_spi_dma_config_tx(struct dw_spi *dws)
 270 {
 271         struct dma_slave_config txconf;
 272
 273         memset(&txconf, 0, sizeof(txconf));
 274         txconf.direction = DMA_MEM_TO_DEV;
 275         txconf.dst_addr = dws->dma_addr;
 276         txconf.dst_maxburst = dws->txburst;
 277         txconf.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
 278         txconf.dst_addr_width = dw_spi_dma_convert_width(dws->n_bytes);
 279         txconf.device_fc = false;
 280
 281         return dmaengine_slave_config(dws->txchan, &txconf);
 282 }
 283
 284 static int dw_spi_dma_submit_tx(struct dw_spi *dws, struct scatterlist *sgl,
 285                                 unsigned int nents)
 286 {
 287         struct dma_async_tx_descriptor *txdesc;
 288         dma_cookie_t cookie;
 289         int ret;
 290
 291         txdesc = dmaengine_prep_slave_sg(dws->txchan, sgl, nents,
 292                                          DMA_MEM_TO_DEV,
 293                                          DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
 294         if (!txdesc)
 295                 return -ENOMEM;
 296
 297         txdesc->callback = dw_spi_dma_tx_done;
 298         txdesc->callback_param = dws;
 299
 300         cookie = dmaengine_submit(txdesc);
 301         ret = dma_submit_error(cookie);
 302         if (ret) {
 303                 dmaengine_terminate_sync(dws->txchan);
 304                 return ret;
 305         }
 306
 307         set_bit(TX_BUSY, &dws->dma_chan_busy);
 308
 309         return 0;
 310 }
 311
 312 static inline bool dw_spi_dma_rx_busy(struct dw_spi *dws)
 313 {
 314         return !!(dw_readl(dws, DW_SPI_SR) & SR_RF_NOT_EMPT);
 315 }
 316
 317 static int dw_spi_dma_wait_rx_done(struct dw_spi *dws)
 318 {
 319         int retry = SPI_WAIT_RETRIES;
 320         struct spi_delay delay;
 321         unsigned long ns, us;
 322         u32 nents;
 323
 324         /*
 325          * It's unlikely that DMA engine is still doing the data fetching, but
 326          * if it's let's give it some reasonable time. The timeout calculation
 327          * is based on the synchronous APB/SSI reference clock rate, on a
 328          * number of data entries left in the Rx FIFO, times a number of clock
 329          * periods normally needed for a single APB read/write transaction
 330          * without PREADY signal utilized (which is true for the DW APB SSI
 331          * controller).
 332          */
 333         nents = dw_readl(dws, DW_SPI_RXFLR);
 334         ns = 4U * NSEC_PER_SEC / dws->max_freq * nents;
 335         if (ns <= NSEC_PER_USEC) {
 336                 delay.unit = SPI_DELAY_UNIT_NSECS;
 337                 delay.value = ns;
 338         } else {
 339                 us = DIV_ROUND_UP(ns, NSEC_PER_USEC);
 340                 delay.unit = SPI_DELAY_UNIT_USECS;
 341                 delay.value = clamp_val(us, 0, USHRT_MAX);
 342         }
 343
 344         while (dw_spi_dma_rx_busy(dws) && retry--)
 345                 spi_delay_exec(&delay, NULL);
 346
 347         if (retry < 0) {
 348                 dev_err(&dws->master->dev, "Rx hanged up\n");
 349                 return -EIO;
 350         }
 351
 352         return 0;
 353 }
 354
 355 /*
 356  * dws->dma_chan_busy is set before the dma transfer starts, callback for rx
 357  * channel will clear a corresponding bit.
 358  */
 359 static void dw_spi_dma_rx_done(void *arg)
 360 {
 361         struct dw_spi *dws = arg;
 362
 363         clear_bit(RX_BUSY, &dws->dma_chan_busy);
 364         if (test_bit(TX_BUSY, &dws->dma_chan_busy))
 365                 return;
 366
 367         complete(&dws->dma_completion);
 368 }
 369
 370 static int dw_spi_dma_config_rx(struct dw_spi *dws)
 371 {
 372         struct dma_slave_config rxconf;
 373
 374         memset(&rxconf, 0, sizeof(rxconf));
 375         rxconf.direction = DMA_DEV_TO_MEM;
 376         rxconf.src_addr = dws->dma_addr;
 377         rxconf.src_maxburst = dws->rxburst;
 378         rxconf.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
 379         rxconf.src_addr_width = dw_spi_dma_convert_width(dws->n_bytes);
 380         rxconf.device_fc = false;
 381
 382         return dmaengine_slave_config(dws->rxchan, &rxconf);
 383 }
 384
 385 static int dw_spi_dma_submit_rx(struct dw_spi *dws, struct scatterlist *sgl,
 386                                 unsigned int nents)
 387 {
 388         struct dma_async_tx_descriptor *rxdesc;
 389         dma_cookie_t cookie;
 390         int ret;
 391
 392         rxdesc = dmaengine_prep_slave_sg(dws->rxchan, sgl, nents,
 393                                          DMA_DEV_TO_MEM,
 394                                          DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
 395         if (!rxdesc)
 396                 return -ENOMEM;
 397
 398         rxdesc->callback = dw_spi_dma_rx_done;
 399         rxdesc->callback_param = dws;
 400
 401         cookie = dmaengine_submit(rxdesc);
 402         ret = dma_submit_error(cookie);
 403         if (ret) {
 404                 dmaengine_terminate_sync(dws->rxchan);
 405                 return ret;
 406         }
 407
 408         set_bit(RX_BUSY, &dws->dma_chan_busy);
 409
 410         return 0;
 411 }
 412
 413 static int dw_spi_dma_setup(struct dw_spi *dws, struct spi_transfer *xfer)
 414 {
 415         u16 imr, dma_ctrl;
 416         int ret;
 417
 418         if (!xfer->tx_buf)
 419                 return -EINVAL;
 420
 421         /* Setup DMA channels */
 422         ret = dw_spi_dma_config_tx(dws);
 423         if (ret)
 424                 return ret;
 425
 426         if (xfer->rx_buf) {
 427                 ret = dw_spi_dma_config_rx(dws);
 428                 if (ret)
 429                         return ret;
 430         }
 431
 432         /* Set the DMA handshaking interface */
 433         dma_ctrl = SPI_DMA_TDMAE;
 434         if (xfer->rx_buf)
 435                 dma_ctrl |= SPI_DMA_RDMAE;
 436         dw_writel(dws, DW_SPI_DMACR, dma_ctrl);
 437
 438         /* Set the interrupt mask */
 439         imr = SPI_INT_TXOI;
 440         if (xfer->rx_buf)
 441                 imr |= SPI_INT_RXUI | SPI_INT_RXOI;
 442         spi_umask_intr(dws, imr);
 443
 444         reinit_completion(&dws->dma_completion);
 445
 446         dws->transfer_handler = dw_spi_dma_transfer_handler;
 447
 448         return 0;
 449 }
 450
 451 static int dw_spi_dma_transfer_all(struct dw_spi *dws,
 452                                    struct spi_transfer *xfer)
 453 {
 454         int ret;
 455
 456         /* Submit the DMA Tx transfer */
 457         ret = dw_spi_dma_submit_tx(dws, xfer->tx_sg.sgl, xfer->tx_sg.nents);
 458         if (ret)
 459                 goto err_clear_dmac;
 460
 461         /* Submit the DMA Rx transfer if required */
 462         if (xfer->rx_buf) {
 463                 ret = dw_spi_dma_submit_rx(dws, xfer->rx_sg.sgl,
 464                                            xfer->rx_sg.nents);
 465                 if (ret)
 466                         goto err_clear_dmac;
 467
 468                 /* rx must be started before tx due to spi instinct */
 469                 dma_async_issue_pending(dws->rxchan);
 470         }
 471
 472         dma_async_issue_pending(dws->txchan);
 473
 474         ret = dw_spi_dma_wait(dws, xfer->len, xfer->effective_speed_hz);
 475
 476 err_clear_dmac:
 477         dw_writel(dws, DW_SPI_DMACR, 0);
 478
 479         return ret;
 480 }
 481
 482 /*
 483  * In case if at least one of the requested DMA channels doesn't support the
 484  * hardware accelerated SG list entries traverse, the DMA driver will most
 485  * likely work that around by performing the IRQ-based SG list entries
 486  * resubmission. That might and will cause a problem if the DMA Tx channel is
 487  * recharged and re-executed before the Rx DMA channel. Due to
 488  * non-deterministic IRQ-handler execution latency the DMA Tx channel will
 489  * start pushing data to the SPI bus before the Rx DMA channel is even
 490  * reinitialized with the next inbound SG list entry. By doing so the DMA Tx
 491  * channel will implicitly start filling the DW APB SSI Rx FIFO up, which while
 492  * the DMA Rx channel being recharged and re-executed will eventually be
 493  * overflown.
 494  *
 495  * In order to solve the problem we have to feed the DMA engine with SG list
 496  * entries one-by-one. It shall keep the DW APB SSI Tx and Rx FIFOs
 497  * synchronized and prevent the Rx FIFO overflow. Since in general the tx_sg
 498  * and rx_sg lists may have different number of entries of different lengths
 499  * (though total length should match) let's virtually split the SG-lists to the
 500  * set of DMA transfers, which length is a minimum of the ordered SG-entries
 501  * lengths. An ASCII-sketch of the implemented algo is following:
 502  *                  xfer->len
 503  *                |___________|
 504  * tx_sg list:    |___|____|__|
 505  * rx_sg list:    |_|____|____|
 506  * DMA transfers: |_|_|__|_|__|
 507  *
 508  * Note in order to have this workaround solving the denoted problem the DMA
 509  * engine driver should properly initialize the max_sg_burst capability and set
 510  * the DMA device max segment size parameter with maximum data block size the
 511  * DMA engine supports.
 512  */
 513
 514 static int dw_spi_dma_transfer_one(struct dw_spi *dws,
 515                                    struct spi_transfer *xfer)
 516 {
 517         struct scatterlist *tx_sg = NULL, *rx_sg = NULL, tx_tmp, rx_tmp;
 518         unsigned int tx_len = 0, rx_len = 0;
 519         unsigned int base, len;
 520         int ret;
 521
 522         sg_init_table(&tx_tmp, 1);
 523         sg_init_table(&rx_tmp, 1);
 524
 525         for (base = 0, len = 0; base < xfer->len; base += len) {
 526                 /* Fetch next Tx DMA data chunk */
 527                 if (!tx_len) {
 528                         tx_sg = !tx_sg ? &xfer->tx_sg.sgl[0] : sg_next(tx_sg);
 529                         sg_dma_address(&tx_tmp) = sg_dma_address(tx_sg);
 530                         tx_len = sg_dma_len(tx_sg);
 531                 }
 532
 533                 /* Fetch next Rx DMA data chunk */
 534                 if (!rx_len) {
 535                         rx_sg = !rx_sg ? &xfer->rx_sg.sgl[0] : sg_next(rx_sg);
 536                         sg_dma_address(&rx_tmp) = sg_dma_address(rx_sg);
 537                         rx_len = sg_dma_len(rx_sg);
 538                 }
 539
 540                 len = min(tx_len, rx_len);
 541
 542                 sg_dma_len(&tx_tmp) = len;
 543                 sg_dma_len(&rx_tmp) = len;
 544
 545                 /* Submit DMA Tx transfer */
 546                 ret = dw_spi_dma_submit_tx(dws, &tx_tmp, 1);
 547                 if (ret)
 548                         break;
 549
 550                 /* Submit DMA Rx transfer */
 551                 ret = dw_spi_dma_submit_rx(dws, &rx_tmp, 1);
 552                 if (ret)
 553                         break;
 554
 555                 /* Rx must be started before Tx due to SPI instinct */
 556                 dma_async_issue_pending(dws->rxchan);
 557
 558                 dma_async_issue_pending(dws->txchan);
 559
 560                 /*
 561                  * Here we only need to wait for the DMA transfer to be
 562                  * finished since SPI controller is kept enabled during the
 563                  * procedure this loop implements and there is no risk to lose
 564                  * data left in the Tx/Rx FIFOs.
 565                  */
 566                 ret = dw_spi_dma_wait(dws, len, xfer->effective_speed_hz);
 567                 if (ret)
 568                         break;
 569
 570                 reinit_completion(&dws->dma_completion);
 571
 572                 sg_dma_address(&tx_tmp) += len;
 573                 sg_dma_address(&rx_tmp) += len;
 574                 tx_len -= len;
 575                 rx_len -= len;
 576         }
 577
 578         dw_writel(dws, DW_SPI_DMACR, 0);
 579
 580         return ret;
 581 }
 582
 583 static int dw_spi_dma_transfer(struct dw_spi *dws, struct spi_transfer *xfer)
 584 {
 585         unsigned int nents;
 586         int ret;
 587
 588         nents = max(xfer->tx_sg.nents, xfer->rx_sg.nents);
 589
 590         /*
 591          * Execute normal DMA-based transfer (which submits the Rx and Tx SG
 592          * lists directly to the DMA engine at once) if either full hardware
 593          * accelerated SG list traverse is supported by both channels, or the
 594          * Tx-only SPI transfer is requested, or the DMA engine is capable to
 595          * handle both SG lists on hardware accelerated basis.
 596          */
 597         if (!dws->dma_sg_burst || !xfer->rx_buf || nents <= dws->dma_sg_burst)
 598                 ret = dw_spi_dma_transfer_all(dws, xfer);
 599         else
 600                 ret = dw_spi_dma_transfer_one(dws, xfer);
 601         if (ret)
 602                 return ret;
 603
 604         if (dws->master->cur_msg->status == -EINPROGRESS) {
 605                 ret = dw_spi_dma_wait_tx_done(dws, xfer);
 606                 if (ret)
 607                         return ret;
 608         }
 609
 610         if (xfer->rx_buf && dws->master->cur_msg->status == -EINPROGRESS)
 611                 ret = dw_spi_dma_wait_rx_done(dws);
 612
 613         return ret;
 614 }
 615
 616 static void dw_spi_dma_stop(struct dw_spi *dws)
 617 {
 618         if (test_bit(TX_BUSY, &dws->dma_chan_busy)) {
 619                 dmaengine_terminate_sync(dws->txchan);
 620                 clear_bit(TX_BUSY, &dws->dma_chan_busy);
 621         }
 622         if (test_bit(RX_BUSY, &dws->dma_chan_busy)) {
 623                 dmaengine_terminate_sync(dws->rxchan);
 624                 clear_bit(RX_BUSY, &dws->dma_chan_busy);
 625         }
 626 }
 627
 628 static const struct dw_spi_dma_ops dw_spi_dma_mfld_ops = {
 629         .dma_init       = dw_spi_dma_init_mfld,
 630         .dma_exit       = dw_spi_dma_exit,
 631         .dma_setup      = dw_spi_dma_setup,
 632         .can_dma        = dw_spi_can_dma,
 633         .dma_transfer   = dw_spi_dma_transfer,
 634         .dma_stop       = dw_spi_dma_stop,
 635 };
 636
 637 void dw_spi_dma_setup_mfld(struct dw_spi *dws)
 638 {
 639         dws->dma_ops = &dw_spi_dma_mfld_ops;
 640 }
 641 EXPORT_SYMBOL_GPL(dw_spi_dma_setup_mfld);
 642
 643 static const struct dw_spi_dma_ops dw_spi_dma_generic_ops = {
 644         .dma_init       = dw_spi_dma_init_generic,
 645         .dma_exit       = dw_spi_dma_exit,
 646         .dma_setup      = dw_spi_dma_setup,
 647         .can_dma        = dw_spi_can_dma,
 648         .dma_transfer   = dw_spi_dma_transfer,
 649         .dma_stop       = dw_spi_dma_stop,
 650 };
 651
 652 void dw_spi_dma_setup_generic(struct dw_spi *dws)
 653 {
 654         dws->dma_ops = &dw_spi_dma_generic_ops;
 655 }
 656 EXPORT_SYMBOL_GPL(dw_spi_dma_setup_generic);