linux/drivers/spi/spi-davinci.c
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   1/*
   2 * Copyright (C) 2009 Texas Instruments.
   3 * Copyright (C) 2010 EF Johnson Technologies
   4 *
   5 * This program is free software; you can redistribute it and/or modify
   6 * it under the terms of the GNU General Public License as published by
   7 * the Free Software Foundation; either version 2 of the License, or
   8 * (at your option) any later version.
   9 *
  10 * This program is distributed in the hope that it will be useful,
  11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 * GNU General Public License for more details.
  14 *
  15 * You should have received a copy of the GNU General Public License
  16 * along with this program; if not, write to the Free Software
  17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18 */
  19
  20#include <linux/interrupt.h>
  21#include <linux/io.h>
  22#include <linux/gpio.h>
  23#include <linux/module.h>
  24#include <linux/delay.h>
  25#include <linux/platform_device.h>
  26#include <linux/err.h>
  27#include <linux/clk.h>
  28#include <linux/dmaengine.h>
  29#include <linux/dma-mapping.h>
  30#include <linux/edma.h>
  31#include <linux/of.h>
  32#include <linux/of_device.h>
  33#include <linux/spi/spi.h>
  34#include <linux/spi/spi_bitbang.h>
  35#include <linux/slab.h>
  36
  37#include <linux/platform_data/spi-davinci.h>
  38
  39#define SPI_NO_RESOURCE         ((resource_size_t)-1)
  40
  41#define SPI_MAX_CHIPSELECT      2
  42
  43#define CS_DEFAULT      0xFF
  44
  45#define SPIFMT_PHASE_MASK       BIT(16)
  46#define SPIFMT_POLARITY_MASK    BIT(17)
  47#define SPIFMT_DISTIMER_MASK    BIT(18)
  48#define SPIFMT_SHIFTDIR_MASK    BIT(20)
  49#define SPIFMT_WAITENA_MASK     BIT(21)
  50#define SPIFMT_PARITYENA_MASK   BIT(22)
  51#define SPIFMT_ODD_PARITY_MASK  BIT(23)
  52#define SPIFMT_WDELAY_MASK      0x3f000000u
  53#define SPIFMT_WDELAY_SHIFT     24
  54#define SPIFMT_PRESCALE_SHIFT   8
  55
  56/* SPIPC0 */
  57#define SPIPC0_DIFUN_MASK       BIT(11)         /* MISO */
  58#define SPIPC0_DOFUN_MASK       BIT(10)         /* MOSI */
  59#define SPIPC0_CLKFUN_MASK      BIT(9)          /* CLK */
  60#define SPIPC0_SPIENA_MASK      BIT(8)          /* nREADY */
  61
  62#define SPIINT_MASKALL          0x0101035F
  63#define SPIINT_MASKINT          0x0000015F
  64#define SPI_INTLVL_1            0x000001FF
  65#define SPI_INTLVL_0            0x00000000
  66
  67/* SPIDAT1 (upper 16 bit defines) */
  68#define SPIDAT1_CSHOLD_MASK     BIT(12)
  69
  70/* SPIGCR1 */
  71#define SPIGCR1_CLKMOD_MASK     BIT(1)
  72#define SPIGCR1_MASTER_MASK     BIT(0)
  73#define SPIGCR1_POWERDOWN_MASK  BIT(8)
  74#define SPIGCR1_LOOPBACK_MASK   BIT(16)
  75#define SPIGCR1_SPIENA_MASK     BIT(24)
  76
  77/* SPIBUF */
  78#define SPIBUF_TXFULL_MASK      BIT(29)
  79#define SPIBUF_RXEMPTY_MASK     BIT(31)
  80
  81/* SPIDELAY */
  82#define SPIDELAY_C2TDELAY_SHIFT 24
  83#define SPIDELAY_C2TDELAY_MASK  (0xFF << SPIDELAY_C2TDELAY_SHIFT)
  84#define SPIDELAY_T2CDELAY_SHIFT 16
  85#define SPIDELAY_T2CDELAY_MASK  (0xFF << SPIDELAY_T2CDELAY_SHIFT)
  86#define SPIDELAY_T2EDELAY_SHIFT 8
  87#define SPIDELAY_T2EDELAY_MASK  (0xFF << SPIDELAY_T2EDELAY_SHIFT)
  88#define SPIDELAY_C2EDELAY_SHIFT 0
  89#define SPIDELAY_C2EDELAY_MASK  0xFF
  90
  91/* Error Masks */
  92#define SPIFLG_DLEN_ERR_MASK            BIT(0)
  93#define SPIFLG_TIMEOUT_MASK             BIT(1)
  94#define SPIFLG_PARERR_MASK              BIT(2)
  95#define SPIFLG_DESYNC_MASK              BIT(3)
  96#define SPIFLG_BITERR_MASK              BIT(4)
  97#define SPIFLG_OVRRUN_MASK              BIT(6)
  98#define SPIFLG_BUF_INIT_ACTIVE_MASK     BIT(24)
  99#define SPIFLG_ERROR_MASK               (SPIFLG_DLEN_ERR_MASK \
 100                                | SPIFLG_TIMEOUT_MASK | SPIFLG_PARERR_MASK \
 101                                | SPIFLG_DESYNC_MASK | SPIFLG_BITERR_MASK \
 102                                | SPIFLG_OVRRUN_MASK)
 103
 104#define SPIINT_DMA_REQ_EN       BIT(16)
 105
 106/* SPI Controller registers */
 107#define SPIGCR0         0x00
 108#define SPIGCR1         0x04
 109#define SPIINT          0x08
 110#define SPILVL          0x0c
 111#define SPIFLG          0x10
 112#define SPIPC0          0x14
 113#define SPIDAT1         0x3c
 114#define SPIBUF          0x40
 115#define SPIDELAY        0x48
 116#define SPIDEF          0x4c
 117#define SPIFMT0         0x50
 118
 119/* SPI Controller driver's private data. */
 120struct davinci_spi {
 121        struct spi_bitbang      bitbang;
 122        struct clk              *clk;
 123
 124        u8                      version;
 125        resource_size_t         pbase;
 126        void __iomem            *base;
 127        u32                     irq;
 128        struct completion       done;
 129
 130        const void              *tx;
 131        void                    *rx;
 132        int                     rcount;
 133        int                     wcount;
 134
 135        struct dma_chan         *dma_rx;
 136        struct dma_chan         *dma_tx;
 137        int                     dma_rx_chnum;
 138        int                     dma_tx_chnum;
 139
 140        struct davinci_spi_platform_data pdata;
 141
 142        void                    (*get_rx)(u32 rx_data, struct davinci_spi *);
 143        u32                     (*get_tx)(struct davinci_spi *);
 144
 145        u8                      bytes_per_word[SPI_MAX_CHIPSELECT];
 146};
 147
 148static struct davinci_spi_config davinci_spi_default_cfg;
 149
 150static void davinci_spi_rx_buf_u8(u32 data, struct davinci_spi *dspi)
 151{
 152        if (dspi->rx) {
 153                u8 *rx = dspi->rx;
 154                *rx++ = (u8)data;
 155                dspi->rx = rx;
 156        }
 157}
 158
 159static void davinci_spi_rx_buf_u16(u32 data, struct davinci_spi *dspi)
 160{
 161        if (dspi->rx) {
 162                u16 *rx = dspi->rx;
 163                *rx++ = (u16)data;
 164                dspi->rx = rx;
 165        }
 166}
 167
 168static u32 davinci_spi_tx_buf_u8(struct davinci_spi *dspi)
 169{
 170        u32 data = 0;
 171        if (dspi->tx) {
 172                const u8 *tx = dspi->tx;
 173                data = *tx++;
 174                dspi->tx = tx;
 175        }
 176        return data;
 177}
 178
 179static u32 davinci_spi_tx_buf_u16(struct davinci_spi *dspi)
 180{
 181        u32 data = 0;
 182        if (dspi->tx) {
 183                const u16 *tx = dspi->tx;
 184                data = *tx++;
 185                dspi->tx = tx;
 186        }
 187        return data;
 188}
 189
 190static inline void set_io_bits(void __iomem *addr, u32 bits)
 191{
 192        u32 v = ioread32(addr);
 193
 194        v |= bits;
 195        iowrite32(v, addr);
 196}
 197
 198static inline void clear_io_bits(void __iomem *addr, u32 bits)
 199{
 200        u32 v = ioread32(addr);
 201
 202        v &= ~bits;
 203        iowrite32(v, addr);
 204}
 205
 206/*
 207 * Interface to control the chip select signal
 208 */
 209static void davinci_spi_chipselect(struct spi_device *spi, int value)
 210{
 211        struct davinci_spi *dspi;
 212        struct davinci_spi_platform_data *pdata;
 213        u8 chip_sel = spi->chip_select;
 214        u16 spidat1 = CS_DEFAULT;
 215        bool gpio_chipsel = false;
 216
 217        dspi = spi_master_get_devdata(spi->master);
 218        pdata = &dspi->pdata;
 219
 220        if (pdata->chip_sel && chip_sel < pdata->num_chipselect &&
 221                                pdata->chip_sel[chip_sel] != SPI_INTERN_CS)
 222                gpio_chipsel = true;
 223
 224        /*
 225         * Board specific chip select logic decides the polarity and cs
 226         * line for the controller
 227         */
 228        if (gpio_chipsel) {
 229                if (value == BITBANG_CS_ACTIVE)
 230                        gpio_set_value(pdata->chip_sel[chip_sel], 0);
 231                else
 232                        gpio_set_value(pdata->chip_sel[chip_sel], 1);
 233        } else {
 234                if (value == BITBANG_CS_ACTIVE) {
 235                        spidat1 |= SPIDAT1_CSHOLD_MASK;
 236                        spidat1 &= ~(0x1 << chip_sel);
 237                }
 238
 239                iowrite16(spidat1, dspi->base + SPIDAT1 + 2);
 240        }
 241}
 242
 243/**
 244 * davinci_spi_get_prescale - Calculates the correct prescale value
 245 * @maxspeed_hz: the maximum rate the SPI clock can run at
 246 *
 247 * This function calculates the prescale value that generates a clock rate
 248 * less than or equal to the specified maximum.
 249 *
 250 * Returns: calculated prescale - 1 for easy programming into SPI registers
 251 * or negative error number if valid prescalar cannot be updated.
 252 */
 253static inline int davinci_spi_get_prescale(struct davinci_spi *dspi,
 254                                                        u32 max_speed_hz)
 255{
 256        int ret;
 257
 258        ret = DIV_ROUND_UP(clk_get_rate(dspi->clk), max_speed_hz);
 259
 260        if (ret < 3 || ret > 256)
 261                return -EINVAL;
 262
 263        return ret - 1;
 264}
 265
 266/**
 267 * davinci_spi_setup_transfer - This functions will determine transfer method
 268 * @spi: spi device on which data transfer to be done
 269 * @t: spi transfer in which transfer info is filled
 270 *
 271 * This function determines data transfer method (8/16/32 bit transfer).
 272 * It will also set the SPI Clock Control register according to
 273 * SPI slave device freq.
 274 */
 275static int davinci_spi_setup_transfer(struct spi_device *spi,
 276                struct spi_transfer *t)
 277{
 278
 279        struct davinci_spi *dspi;
 280        struct davinci_spi_config *spicfg;
 281        u8 bits_per_word = 0;
 282        u32 hz = 0, spifmt = 0, prescale = 0;
 283
 284        dspi = spi_master_get_devdata(spi->master);
 285        spicfg = (struct davinci_spi_config *)spi->controller_data;
 286        if (!spicfg)
 287                spicfg = &davinci_spi_default_cfg;
 288
 289        if (t) {
 290                bits_per_word = t->bits_per_word;
 291                hz = t->speed_hz;
 292        }
 293
 294        /* if bits_per_word is not set then set it default */
 295        if (!bits_per_word)
 296                bits_per_word = spi->bits_per_word;
 297
 298        /*
 299         * Assign function pointer to appropriate transfer method
 300         * 8bit, 16bit or 32bit transfer
 301         */
 302        if (bits_per_word <= 8) {
 303                dspi->get_rx = davinci_spi_rx_buf_u8;
 304                dspi->get_tx = davinci_spi_tx_buf_u8;
 305                dspi->bytes_per_word[spi->chip_select] = 1;
 306        } else {
 307                dspi->get_rx = davinci_spi_rx_buf_u16;
 308                dspi->get_tx = davinci_spi_tx_buf_u16;
 309                dspi->bytes_per_word[spi->chip_select] = 2;
 310        }
 311
 312        if (!hz)
 313                hz = spi->max_speed_hz;
 314
 315        /* Set up SPIFMTn register, unique to this chipselect. */
 316
 317        prescale = davinci_spi_get_prescale(dspi, hz);
 318        if (prescale < 0)
 319                return prescale;
 320
 321        spifmt = (prescale << SPIFMT_PRESCALE_SHIFT) | (bits_per_word & 0x1f);
 322
 323        if (spi->mode & SPI_LSB_FIRST)
 324                spifmt |= SPIFMT_SHIFTDIR_MASK;
 325
 326        if (spi->mode & SPI_CPOL)
 327                spifmt |= SPIFMT_POLARITY_MASK;
 328
 329        if (!(spi->mode & SPI_CPHA))
 330                spifmt |= SPIFMT_PHASE_MASK;
 331
 332        /*
 333         * Version 1 hardware supports two basic SPI modes:
 334         *  - Standard SPI mode uses 4 pins, with chipselect
 335         *  - 3 pin SPI is a 4 pin variant without CS (SPI_NO_CS)
 336         *      (distinct from SPI_3WIRE, with just one data wire;
 337         *      or similar variants without MOSI or without MISO)
 338         *
 339         * Version 2 hardware supports an optional handshaking signal,
 340         * so it can support two more modes:
 341         *  - 5 pin SPI variant is standard SPI plus SPI_READY
 342         *  - 4 pin with enable is (SPI_READY | SPI_NO_CS)
 343         */
 344
 345        if (dspi->version == SPI_VERSION_2) {
 346
 347                u32 delay = 0;
 348
 349                spifmt |= ((spicfg->wdelay << SPIFMT_WDELAY_SHIFT)
 350                                                        & SPIFMT_WDELAY_MASK);
 351
 352                if (spicfg->odd_parity)
 353                        spifmt |= SPIFMT_ODD_PARITY_MASK;
 354
 355                if (spicfg->parity_enable)
 356                        spifmt |= SPIFMT_PARITYENA_MASK;
 357
 358                if (spicfg->timer_disable) {
 359                        spifmt |= SPIFMT_DISTIMER_MASK;
 360                } else {
 361                        delay |= (spicfg->c2tdelay << SPIDELAY_C2TDELAY_SHIFT)
 362                                                & SPIDELAY_C2TDELAY_MASK;
 363                        delay |= (spicfg->t2cdelay << SPIDELAY_T2CDELAY_SHIFT)
 364                                                & SPIDELAY_T2CDELAY_MASK;
 365                }
 366
 367                if (spi->mode & SPI_READY) {
 368                        spifmt |= SPIFMT_WAITENA_MASK;
 369                        delay |= (spicfg->t2edelay << SPIDELAY_T2EDELAY_SHIFT)
 370                                                & SPIDELAY_T2EDELAY_MASK;
 371                        delay |= (spicfg->c2edelay << SPIDELAY_C2EDELAY_SHIFT)
 372                                                & SPIDELAY_C2EDELAY_MASK;
 373                }
 374
 375                iowrite32(delay, dspi->base + SPIDELAY);
 376        }
 377
 378        iowrite32(spifmt, dspi->base + SPIFMT0);
 379
 380        return 0;
 381}
 382
 383/**
 384 * davinci_spi_setup - This functions will set default transfer method
 385 * @spi: spi device on which data transfer to be done
 386 *
 387 * This functions sets the default transfer method.
 388 */
 389static int davinci_spi_setup(struct spi_device *spi)
 390{
 391        int retval = 0;
 392        struct davinci_spi *dspi;
 393        struct davinci_spi_platform_data *pdata;
 394
 395        dspi = spi_master_get_devdata(spi->master);
 396        pdata = &dspi->pdata;
 397
 398        /* if bits per word length is zero then set it default 8 */
 399        if (!spi->bits_per_word)
 400                spi->bits_per_word = 8;
 401
 402        if (!(spi->mode & SPI_NO_CS)) {
 403                if ((pdata->chip_sel == NULL) ||
 404                    (pdata->chip_sel[spi->chip_select] == SPI_INTERN_CS))
 405                        set_io_bits(dspi->base + SPIPC0, 1 << spi->chip_select);
 406
 407        }
 408
 409        if (spi->mode & SPI_READY)
 410                set_io_bits(dspi->base + SPIPC0, SPIPC0_SPIENA_MASK);
 411
 412        if (spi->mode & SPI_LOOP)
 413                set_io_bits(dspi->base + SPIGCR1, SPIGCR1_LOOPBACK_MASK);
 414        else
 415                clear_io_bits(dspi->base + SPIGCR1, SPIGCR1_LOOPBACK_MASK);
 416
 417        return retval;
 418}
 419
 420static int davinci_spi_check_error(struct davinci_spi *dspi, int int_status)
 421{
 422        struct device *sdev = dspi->bitbang.master->dev.parent;
 423
 424        if (int_status & SPIFLG_TIMEOUT_MASK) {
 425                dev_dbg(sdev, "SPI Time-out Error\n");
 426                return -ETIMEDOUT;
 427        }
 428        if (int_status & SPIFLG_DESYNC_MASK) {
 429                dev_dbg(sdev, "SPI Desynchronization Error\n");
 430                return -EIO;
 431        }
 432        if (int_status & SPIFLG_BITERR_MASK) {
 433                dev_dbg(sdev, "SPI Bit error\n");
 434                return -EIO;
 435        }
 436
 437        if (dspi->version == SPI_VERSION_2) {
 438                if (int_status & SPIFLG_DLEN_ERR_MASK) {
 439                        dev_dbg(sdev, "SPI Data Length Error\n");
 440                        return -EIO;
 441                }
 442                if (int_status & SPIFLG_PARERR_MASK) {
 443                        dev_dbg(sdev, "SPI Parity Error\n");
 444                        return -EIO;
 445                }
 446                if (int_status & SPIFLG_OVRRUN_MASK) {
 447                        dev_dbg(sdev, "SPI Data Overrun error\n");
 448                        return -EIO;
 449                }
 450                if (int_status & SPIFLG_BUF_INIT_ACTIVE_MASK) {
 451                        dev_dbg(sdev, "SPI Buffer Init Active\n");
 452                        return -EBUSY;
 453                }
 454        }
 455
 456        return 0;
 457}
 458
 459/**
 460 * davinci_spi_process_events - check for and handle any SPI controller events
 461 * @dspi: the controller data
 462 *
 463 * This function will check the SPIFLG register and handle any events that are
 464 * detected there
 465 */
 466static int davinci_spi_process_events(struct davinci_spi *dspi)
 467{
 468        u32 buf, status, errors = 0, spidat1;
 469
 470        buf = ioread32(dspi->base + SPIBUF);
 471
 472        if (dspi->rcount > 0 && !(buf & SPIBUF_RXEMPTY_MASK)) {
 473                dspi->get_rx(buf & 0xFFFF, dspi);
 474                dspi->rcount--;
 475        }
 476
 477        status = ioread32(dspi->base + SPIFLG);
 478
 479        if (unlikely(status & SPIFLG_ERROR_MASK)) {
 480                errors = status & SPIFLG_ERROR_MASK;
 481                goto out;
 482        }
 483
 484        if (dspi->wcount > 0 && !(buf & SPIBUF_TXFULL_MASK)) {
 485                spidat1 = ioread32(dspi->base + SPIDAT1);
 486                dspi->wcount--;
 487                spidat1 &= ~0xFFFF;
 488                spidat1 |= 0xFFFF & dspi->get_tx(dspi);
 489                iowrite32(spidat1, dspi->base + SPIDAT1);
 490        }
 491
 492out:
 493        return errors;
 494}
 495
 496static void davinci_spi_dma_rx_callback(void *data)
 497{
 498        struct davinci_spi *dspi = (struct davinci_spi *)data;
 499
 500        dspi->rcount = 0;
 501
 502        if (!dspi->wcount && !dspi->rcount)
 503                complete(&dspi->done);
 504}
 505
 506static void davinci_spi_dma_tx_callback(void *data)
 507{
 508        struct davinci_spi *dspi = (struct davinci_spi *)data;
 509
 510        dspi->wcount = 0;
 511
 512        if (!dspi->wcount && !dspi->rcount)
 513                complete(&dspi->done);
 514}
 515
 516/**
 517 * davinci_spi_bufs - functions which will handle transfer data
 518 * @spi: spi device on which data transfer to be done
 519 * @t: spi transfer in which transfer info is filled
 520 *
 521 * This function will put data to be transferred into data register
 522 * of SPI controller and then wait until the completion will be marked
 523 * by the IRQ Handler.
 524 */
 525static int davinci_spi_bufs(struct spi_device *spi, struct spi_transfer *t)
 526{
 527        struct davinci_spi *dspi;
 528        int data_type, ret = -ENOMEM;
 529        u32 tx_data, spidat1;
 530        u32 errors = 0;
 531        struct davinci_spi_config *spicfg;
 532        struct davinci_spi_platform_data *pdata;
 533        unsigned uninitialized_var(rx_buf_count);
 534        void *dummy_buf = NULL;
 535        struct scatterlist sg_rx, sg_tx;
 536
 537        dspi = spi_master_get_devdata(spi->master);
 538        pdata = &dspi->pdata;
 539        spicfg = (struct davinci_spi_config *)spi->controller_data;
 540        if (!spicfg)
 541                spicfg = &davinci_spi_default_cfg;
 542
 543        /* convert len to words based on bits_per_word */
 544        data_type = dspi->bytes_per_word[spi->chip_select];
 545
 546        dspi->tx = t->tx_buf;
 547        dspi->rx = t->rx_buf;
 548        dspi->wcount = t->len / data_type;
 549        dspi->rcount = dspi->wcount;
 550
 551        spidat1 = ioread32(dspi->base + SPIDAT1);
 552
 553        clear_io_bits(dspi->base + SPIGCR1, SPIGCR1_POWERDOWN_MASK);
 554        set_io_bits(dspi->base + SPIGCR1, SPIGCR1_SPIENA_MASK);
 555
 556        INIT_COMPLETION(dspi->done);
 557
 558        if (spicfg->io_type == SPI_IO_TYPE_INTR)
 559                set_io_bits(dspi->base + SPIINT, SPIINT_MASKINT);
 560
 561        if (spicfg->io_type != SPI_IO_TYPE_DMA) {
 562                /* start the transfer */
 563                dspi->wcount--;
 564                tx_data = dspi->get_tx(dspi);
 565                spidat1 &= 0xFFFF0000;
 566                spidat1 |= tx_data & 0xFFFF;
 567                iowrite32(spidat1, dspi->base + SPIDAT1);
 568        } else {
 569                struct dma_slave_config dma_rx_conf = {
 570                        .direction = DMA_DEV_TO_MEM,
 571                        .src_addr = (unsigned long)dspi->pbase + SPIBUF,
 572                        .src_addr_width = data_type,
 573                        .src_maxburst = 1,
 574                };
 575                struct dma_slave_config dma_tx_conf = {
 576                        .direction = DMA_MEM_TO_DEV,
 577                        .dst_addr = (unsigned long)dspi->pbase + SPIDAT1,
 578                        .dst_addr_width = data_type,
 579                        .dst_maxburst = 1,
 580                };
 581                struct dma_async_tx_descriptor *rxdesc;
 582                struct dma_async_tx_descriptor *txdesc;
 583                void *buf;
 584
 585                dummy_buf = kzalloc(t->len, GFP_KERNEL);
 586                if (!dummy_buf)
 587                        goto err_alloc_dummy_buf;
 588
 589                dmaengine_slave_config(dspi->dma_rx, &dma_rx_conf);
 590                dmaengine_slave_config(dspi->dma_tx, &dma_tx_conf);
 591
 592                sg_init_table(&sg_rx, 1);
 593                if (!t->rx_buf)
 594                        buf = dummy_buf;
 595                else
 596                        buf = t->rx_buf;
 597                t->rx_dma = dma_map_single(&spi->dev, buf,
 598                                t->len, DMA_FROM_DEVICE);
 599                if (!t->rx_dma) {
 600                        ret = -EFAULT;
 601                        goto err_rx_map;
 602                }
 603                sg_dma_address(&sg_rx) = t->rx_dma;
 604                sg_dma_len(&sg_rx) = t->len;
 605
 606                sg_init_table(&sg_tx, 1);
 607                if (!t->tx_buf)
 608                        buf = dummy_buf;
 609                else
 610                        buf = (void *)t->tx_buf;
 611                t->tx_dma = dma_map_single(&spi->dev, buf,
 612                                t->len, DMA_TO_DEVICE);
 613                if (!t->tx_dma) {
 614                        ret = -EFAULT;
 615                        goto err_tx_map;
 616                }
 617                sg_dma_address(&sg_tx) = t->tx_dma;
 618                sg_dma_len(&sg_tx) = t->len;
 619
 620                rxdesc = dmaengine_prep_slave_sg(dspi->dma_rx,
 621                                &sg_rx, 1, DMA_DEV_TO_MEM,
 622                                DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
 623                if (!rxdesc)
 624                        goto err_desc;
 625
 626                txdesc = dmaengine_prep_slave_sg(dspi->dma_tx,
 627                                &sg_tx, 1, DMA_MEM_TO_DEV,
 628                                DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
 629                if (!txdesc)
 630                        goto err_desc;
 631
 632                rxdesc->callback = davinci_spi_dma_rx_callback;
 633                rxdesc->callback_param = (void *)dspi;
 634                txdesc->callback = davinci_spi_dma_tx_callback;
 635                txdesc->callback_param = (void *)dspi;
 636
 637                if (pdata->cshold_bug)
 638                        iowrite16(spidat1 >> 16, dspi->base + SPIDAT1 + 2);
 639
 640                dmaengine_submit(rxdesc);
 641                dmaengine_submit(txdesc);
 642
 643                dma_async_issue_pending(dspi->dma_rx);
 644                dma_async_issue_pending(dspi->dma_tx);
 645
 646                set_io_bits(dspi->base + SPIINT, SPIINT_DMA_REQ_EN);
 647        }
 648
 649        /* Wait for the transfer to complete */
 650        if (spicfg->io_type != SPI_IO_TYPE_POLL) {
 651                wait_for_completion_interruptible(&(dspi->done));
 652        } else {
 653                while (dspi->rcount > 0 || dspi->wcount > 0) {
 654                        errors = davinci_spi_process_events(dspi);
 655                        if (errors)
 656                                break;
 657                        cpu_relax();
 658                }
 659        }
 660
 661        clear_io_bits(dspi->base + SPIINT, SPIINT_MASKALL);
 662        if (spicfg->io_type == SPI_IO_TYPE_DMA) {
 663                clear_io_bits(dspi->base + SPIINT, SPIINT_DMA_REQ_EN);
 664
 665                dma_unmap_single(&spi->dev, t->rx_dma,
 666                                t->len, DMA_FROM_DEVICE);
 667                dma_unmap_single(&spi->dev, t->tx_dma,
 668                                t->len, DMA_TO_DEVICE);
 669                kfree(dummy_buf);
 670        }
 671
 672        clear_io_bits(dspi->base + SPIGCR1, SPIGCR1_SPIENA_MASK);
 673        set_io_bits(dspi->base + SPIGCR1, SPIGCR1_POWERDOWN_MASK);
 674
 675        /*
 676         * Check for bit error, desync error,parity error,timeout error and
 677         * receive overflow errors
 678         */
 679        if (errors) {
 680                ret = davinci_spi_check_error(dspi, errors);
 681                WARN(!ret, "%s: error reported but no error found!\n",
 682                                                        dev_name(&spi->dev));
 683                return ret;
 684        }
 685
 686        if (dspi->rcount != 0 || dspi->wcount != 0) {
 687                dev_err(&spi->dev, "SPI data transfer error\n");
 688                return -EIO;
 689        }
 690
 691        return t->len;
 692
 693err_desc:
 694        dma_unmap_single(&spi->dev, t->tx_dma, t->len, DMA_TO_DEVICE);
 695err_tx_map:
 696        dma_unmap_single(&spi->dev, t->rx_dma, t->len, DMA_FROM_DEVICE);
 697err_rx_map:
 698        kfree(dummy_buf);
 699err_alloc_dummy_buf:
 700        return ret;
 701}
 702
 703/**
 704 * dummy_thread_fn - dummy thread function
 705 * @irq: IRQ number for this SPI Master
 706 * @context_data: structure for SPI Master controller davinci_spi
 707 *
 708 * This is to satisfy the request_threaded_irq() API so that the irq
 709 * handler is called in interrupt context.
 710 */
 711static irqreturn_t dummy_thread_fn(s32 irq, void *data)
 712{
 713        return IRQ_HANDLED;
 714}
 715
 716/**
 717 * davinci_spi_irq - Interrupt handler for SPI Master Controller
 718 * @irq: IRQ number for this SPI Master
 719 * @context_data: structure for SPI Master controller davinci_spi
 720 *
 721 * ISR will determine that interrupt arrives either for READ or WRITE command.
 722 * According to command it will do the appropriate action. It will check
 723 * transfer length and if it is not zero then dispatch transfer command again.
 724 * If transfer length is zero then it will indicate the COMPLETION so that
 725 * davinci_spi_bufs function can go ahead.
 726 */
 727static irqreturn_t davinci_spi_irq(s32 irq, void *data)
 728{
 729        struct davinci_spi *dspi = data;
 730        int status;
 731
 732        status = davinci_spi_process_events(dspi);
 733        if (unlikely(status != 0))
 734                clear_io_bits(dspi->base + SPIINT, SPIINT_MASKINT);
 735
 736        if ((!dspi->rcount && !dspi->wcount) || status)
 737                complete(&dspi->done);
 738
 739        return IRQ_HANDLED;
 740}
 741
 742static int davinci_spi_request_dma(struct davinci_spi *dspi)
 743{
 744        dma_cap_mask_t mask;
 745        struct device *sdev = dspi->bitbang.master->dev.parent;
 746        int r;
 747
 748        dma_cap_zero(mask);
 749        dma_cap_set(DMA_SLAVE, mask);
 750
 751        dspi->dma_rx = dma_request_channel(mask, edma_filter_fn,
 752                                           &dspi->dma_rx_chnum);
 753        if (!dspi->dma_rx) {
 754                dev_err(sdev, "request RX DMA channel failed\n");
 755                r = -ENODEV;
 756                goto rx_dma_failed;
 757        }
 758
 759        dspi->dma_tx = dma_request_channel(mask, edma_filter_fn,
 760                                           &dspi->dma_tx_chnum);
 761        if (!dspi->dma_tx) {
 762                dev_err(sdev, "request TX DMA channel failed\n");
 763                r = -ENODEV;
 764                goto tx_dma_failed;
 765        }
 766
 767        return 0;
 768
 769tx_dma_failed:
 770        dma_release_channel(dspi->dma_rx);
 771rx_dma_failed:
 772        return r;
 773}
 774
 775#if defined(CONFIG_OF)
 776static const struct of_device_id davinci_spi_of_match[] = {
 777        {
 778                .compatible = "ti,dm6441-spi",
 779        },
 780        {
 781                .compatible = "ti,da830-spi",
 782                .data = (void *)SPI_VERSION_2,
 783        },
 784        { },
 785};
 786MODULE_DEVICE_TABLE(of, davinci_spi_of_match);
 787
 788/**
 789 * spi_davinci_get_pdata - Get platform data from DTS binding
 790 * @pdev: ptr to platform data
 791 * @dspi: ptr to driver data
 792 *
 793 * Parses and populates pdata in dspi from device tree bindings.
 794 *
 795 * NOTE: Not all platform data params are supported currently.
 796 */
 797static int spi_davinci_get_pdata(struct platform_device *pdev,
 798                        struct davinci_spi *dspi)
 799{
 800        struct device_node *node = pdev->dev.of_node;
 801        struct davinci_spi_platform_data *pdata;
 802        unsigned int num_cs, intr_line = 0;
 803        const struct of_device_id *match;
 804
 805        pdata = &dspi->pdata;
 806
 807        pdata->version = SPI_VERSION_1;
 808        match = of_match_device(of_match_ptr(davinci_spi_of_match),
 809                                &pdev->dev);
 810        if (!match)
 811                return -ENODEV;
 812
 813        /* match data has the SPI version number for SPI_VERSION_2 */
 814        if (match->data == (void *)SPI_VERSION_2)
 815                pdata->version = SPI_VERSION_2;
 816
 817        /*
 818         * default num_cs is 1 and all chipsel are internal to the chip
 819         * indicated by chip_sel being NULL. GPIO based CS is not
 820         * supported yet in DT bindings.
 821         */
 822        num_cs = 1;
 823        of_property_read_u32(node, "num-cs", &num_cs);
 824        pdata->num_chipselect = num_cs;
 825        of_property_read_u32(node, "ti,davinci-spi-intr-line", &intr_line);
 826        pdata->intr_line = intr_line;
 827        return 0;
 828}
 829#else
 830#define davinci_spi_of_match NULL
 831static struct davinci_spi_platform_data
 832        *spi_davinci_get_pdata(struct platform_device *pdev,
 833                struct davinci_spi *dspi)
 834{
 835        return -ENODEV;
 836}
 837#endif
 838
 839/**
 840 * davinci_spi_probe - probe function for SPI Master Controller
 841 * @pdev: platform_device structure which contains plateform specific data
 842 *
 843 * According to Linux Device Model this function will be invoked by Linux
 844 * with platform_device struct which contains the device specific info.
 845 * This function will map the SPI controller's memory, register IRQ,
 846 * Reset SPI controller and setting its registers to default value.
 847 * It will invoke spi_bitbang_start to create work queue so that client driver
 848 * can register transfer method to work queue.
 849 */
 850static int davinci_spi_probe(struct platform_device *pdev)
 851{
 852        struct spi_master *master;
 853        struct davinci_spi *dspi;
 854        struct davinci_spi_platform_data *pdata;
 855        struct resource *r, *mem;
 856        resource_size_t dma_rx_chan = SPI_NO_RESOURCE;
 857        resource_size_t dma_tx_chan = SPI_NO_RESOURCE;
 858        int i = 0, ret = 0;
 859        u32 spipc0;
 860
 861        master = spi_alloc_master(&pdev->dev, sizeof(struct davinci_spi));
 862        if (master == NULL) {
 863                ret = -ENOMEM;
 864                goto err;
 865        }
 866
 867        platform_set_drvdata(pdev, master);
 868
 869        dspi = spi_master_get_devdata(master);
 870        if (dspi == NULL) {
 871                ret = -ENOENT;
 872                goto free_master;
 873        }
 874
 875        if (pdev->dev.platform_data) {
 876                pdata = pdev->dev.platform_data;
 877                dspi->pdata = *pdata;
 878        } else {
 879                /* update dspi pdata with that from the DT */
 880                ret = spi_davinci_get_pdata(pdev, dspi);
 881                if (ret < 0)
 882                        goto free_master;
 883        }
 884
 885        /* pdata in dspi is now updated and point pdata to that */
 886        pdata = &dspi->pdata;
 887
 888        r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 889        if (r == NULL) {
 890                ret = -ENOENT;
 891                goto free_master;
 892        }
 893
 894        dspi->pbase = r->start;
 895
 896        mem = request_mem_region(r->start, resource_size(r), pdev->name);
 897        if (mem == NULL) {
 898                ret = -EBUSY;
 899                goto free_master;
 900        }
 901
 902        dspi->base = ioremap(r->start, resource_size(r));
 903        if (dspi->base == NULL) {
 904                ret = -ENOMEM;
 905                goto release_region;
 906        }
 907
 908        dspi->irq = platform_get_irq(pdev, 0);
 909        if (dspi->irq <= 0) {
 910                ret = -EINVAL;
 911                goto unmap_io;
 912        }
 913
 914        ret = request_threaded_irq(dspi->irq, davinci_spi_irq, dummy_thread_fn,
 915                                 0, dev_name(&pdev->dev), dspi);
 916        if (ret)
 917                goto unmap_io;
 918
 919        dspi->bitbang.master = spi_master_get(master);
 920        if (dspi->bitbang.master == NULL) {
 921                ret = -ENODEV;
 922                goto irq_free;
 923        }
 924
 925        dspi->clk = clk_get(&pdev->dev, NULL);
 926        if (IS_ERR(dspi->clk)) {
 927                ret = -ENODEV;
 928                goto put_master;
 929        }
 930        clk_prepare_enable(dspi->clk);
 931
 932        master->dev.of_node = pdev->dev.of_node;
 933        master->bus_num = pdev->id;
 934        master->num_chipselect = pdata->num_chipselect;
 935        master->bits_per_word_mask = SPI_BPW_RANGE_MASK(2, 16);
 936        master->setup = davinci_spi_setup;
 937
 938        dspi->bitbang.chipselect = davinci_spi_chipselect;
 939        dspi->bitbang.setup_transfer = davinci_spi_setup_transfer;
 940
 941        dspi->version = pdata->version;
 942
 943        dspi->bitbang.flags = SPI_NO_CS | SPI_LSB_FIRST | SPI_LOOP;
 944        if (dspi->version == SPI_VERSION_2)
 945                dspi->bitbang.flags |= SPI_READY;
 946
 947        r = platform_get_resource(pdev, IORESOURCE_DMA, 0);
 948        if (r)
 949                dma_rx_chan = r->start;
 950        r = platform_get_resource(pdev, IORESOURCE_DMA, 1);
 951        if (r)
 952                dma_tx_chan = r->start;
 953
 954        dspi->bitbang.txrx_bufs = davinci_spi_bufs;
 955        if (dma_rx_chan != SPI_NO_RESOURCE &&
 956            dma_tx_chan != SPI_NO_RESOURCE) {
 957                dspi->dma_rx_chnum = dma_rx_chan;
 958                dspi->dma_tx_chnum = dma_tx_chan;
 959
 960                ret = davinci_spi_request_dma(dspi);
 961                if (ret)
 962                        goto free_clk;
 963
 964                dev_info(&pdev->dev, "DMA: supported\n");
 965                dev_info(&pdev->dev, "DMA: RX channel: %d, TX channel: %d, "
 966                                "event queue: %d\n", dma_rx_chan, dma_tx_chan,
 967                                pdata->dma_event_q);
 968        }
 969
 970        dspi->get_rx = davinci_spi_rx_buf_u8;
 971        dspi->get_tx = davinci_spi_tx_buf_u8;
 972
 973        init_completion(&dspi->done);
 974
 975        /* Reset In/OUT SPI module */
 976        iowrite32(0, dspi->base + SPIGCR0);
 977        udelay(100);
 978        iowrite32(1, dspi->base + SPIGCR0);
 979
 980        /* Set up SPIPC0.  CS and ENA init is done in davinci_spi_setup */
 981        spipc0 = SPIPC0_DIFUN_MASK | SPIPC0_DOFUN_MASK | SPIPC0_CLKFUN_MASK;
 982        iowrite32(spipc0, dspi->base + SPIPC0);
 983
 984        /* initialize chip selects */
 985        if (pdata->chip_sel) {
 986                for (i = 0; i < pdata->num_chipselect; i++) {
 987                        if (pdata->chip_sel[i] != SPI_INTERN_CS)
 988                                gpio_direction_output(pdata->chip_sel[i], 1);
 989                }
 990        }
 991
 992        if (pdata->intr_line)
 993                iowrite32(SPI_INTLVL_1, dspi->base + SPILVL);
 994        else
 995                iowrite32(SPI_INTLVL_0, dspi->base + SPILVL);
 996
 997        iowrite32(CS_DEFAULT, dspi->base + SPIDEF);
 998
 999        /* master mode default */
1000        set_io_bits(dspi->base + SPIGCR1, SPIGCR1_CLKMOD_MASK);
1001        set_io_bits(dspi->base + SPIGCR1, SPIGCR1_MASTER_MASK);
1002        set_io_bits(dspi->base + SPIGCR1, SPIGCR1_POWERDOWN_MASK);
1003
1004        ret = spi_bitbang_start(&dspi->bitbang);
1005        if (ret)
1006                goto free_dma;
1007
1008        dev_info(&pdev->dev, "Controller at 0x%p\n", dspi->base);
1009
1010        return ret;
1011
1012free_dma:
1013        dma_release_channel(dspi->dma_rx);
1014        dma_release_channel(dspi->dma_tx);
1015free_clk:
1016        clk_disable_unprepare(dspi->clk);
1017        clk_put(dspi->clk);
1018put_master:
1019        spi_master_put(master);
1020irq_free:
1021        free_irq(dspi->irq, dspi);
1022unmap_io:
1023        iounmap(dspi->base);
1024release_region:
1025        release_mem_region(dspi->pbase, resource_size(r));
1026free_master:
1027        kfree(master);
1028err:
1029        return ret;
1030}
1031
1032/**
1033 * davinci_spi_remove - remove function for SPI Master Controller
1034 * @pdev: platform_device structure which contains plateform specific data
1035 *
1036 * This function will do the reverse action of davinci_spi_probe function
1037 * It will free the IRQ and SPI controller's memory region.
1038 * It will also call spi_bitbang_stop to destroy the work queue which was
1039 * created by spi_bitbang_start.
1040 */
1041static int davinci_spi_remove(struct platform_device *pdev)
1042{
1043        struct davinci_spi *dspi;
1044        struct spi_master *master;
1045        struct resource *r;
1046
1047        master = platform_get_drvdata(pdev);
1048        dspi = spi_master_get_devdata(master);
1049
1050        spi_bitbang_stop(&dspi->bitbang);
1051
1052        clk_disable_unprepare(dspi->clk);
1053        clk_put(dspi->clk);
1054        spi_master_put(master);
1055        free_irq(dspi->irq, dspi);
1056        iounmap(dspi->base);
1057        r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1058        release_mem_region(dspi->pbase, resource_size(r));
1059
1060        return 0;
1061}
1062
1063static struct platform_driver davinci_spi_driver = {
1064        .driver = {
1065                .name = "spi_davinci",
1066                .owner = THIS_MODULE,
1067                .of_match_table = davinci_spi_of_match,
1068        },
1069        .probe = davinci_spi_probe,
1070        .remove = davinci_spi_remove,
1071};
1072module_platform_driver(davinci_spi_driver);
1073
1074MODULE_DESCRIPTION("TI DaVinci SPI Master Controller Driver");
1075MODULE_LICENSE("GPL");
1076
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