linux/drivers/spi/omap2_mcspi.c
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   1/*
   2 * OMAP2 McSPI controller driver
   3 *
   4 * Copyright (C) 2005, 2006 Nokia Corporation
   5 * Author:      Samuel Ortiz <samuel.ortiz@nokia.com> and
   6 *              Juha Yrjölä <juha.yrjola@nokia.com>
   7 *
   8 * This program is free software; you can redistribute it and/or modify
   9 * it under the terms of the GNU General Public License as published by
  10 * the Free Software Foundation; either version 2 of the License, or
  11 * (at your option) any later version.
  12 *
  13 * This program is distributed in the hope that it will be useful,
  14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  16 * GNU General Public License for more details.
  17 *
  18 * You should have received a copy of the GNU General Public License
  19 * along with this program; if not, write to the Free Software
  20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  21 *
  22 */
  23
  24#include <linux/kernel.h>
  25#include <linux/init.h>
  26#include <linux/interrupt.h>
  27#include <linux/module.h>
  28#include <linux/device.h>
  29#include <linux/delay.h>
  30#include <linux/dma-mapping.h>
  31#include <linux/platform_device.h>
  32#include <linux/err.h>
  33#include <linux/clk.h>
  34#include <linux/io.h>
  35
  36#include <linux/spi/spi.h>
  37
  38#include <asm/arch/dma.h>
  39#include <asm/arch/clock.h>
  40
  41
  42#define OMAP2_MCSPI_MAX_FREQ            48000000
  43
  44#define OMAP2_MCSPI_REVISION            0x00
  45#define OMAP2_MCSPI_SYSCONFIG           0x10
  46#define OMAP2_MCSPI_SYSSTATUS           0x14
  47#define OMAP2_MCSPI_IRQSTATUS           0x18
  48#define OMAP2_MCSPI_IRQENABLE           0x1c
  49#define OMAP2_MCSPI_WAKEUPENABLE        0x20
  50#define OMAP2_MCSPI_SYST                0x24
  51#define OMAP2_MCSPI_MODULCTRL           0x28
  52
  53/* per-channel banks, 0x14 bytes each, first is: */
  54#define OMAP2_MCSPI_CHCONF0             0x2c
  55#define OMAP2_MCSPI_CHSTAT0             0x30
  56#define OMAP2_MCSPI_CHCTRL0             0x34
  57#define OMAP2_MCSPI_TX0                 0x38
  58#define OMAP2_MCSPI_RX0                 0x3c
  59
  60/* per-register bitmasks: */
  61
  62#define OMAP2_MCSPI_SYSCONFIG_AUTOIDLE  (1 << 0)
  63#define OMAP2_MCSPI_SYSCONFIG_SOFTRESET (1 << 1)
  64
  65#define OMAP2_MCSPI_SYSSTATUS_RESETDONE (1 << 0)
  66
  67#define OMAP2_MCSPI_MODULCTRL_SINGLE    (1 << 0)
  68#define OMAP2_MCSPI_MODULCTRL_MS        (1 << 2)
  69#define OMAP2_MCSPI_MODULCTRL_STEST     (1 << 3)
  70
  71#define OMAP2_MCSPI_CHCONF_PHA          (1 << 0)
  72#define OMAP2_MCSPI_CHCONF_POL          (1 << 1)
  73#define OMAP2_MCSPI_CHCONF_CLKD_MASK    (0x0f << 2)
  74#define OMAP2_MCSPI_CHCONF_EPOL         (1 << 6)
  75#define OMAP2_MCSPI_CHCONF_WL_MASK      (0x1f << 7)
  76#define OMAP2_MCSPI_CHCONF_TRM_RX_ONLY  (0x01 << 12)
  77#define OMAP2_MCSPI_CHCONF_TRM_TX_ONLY  (0x02 << 12)
  78#define OMAP2_MCSPI_CHCONF_TRM_MASK     (0x03 << 12)
  79#define OMAP2_MCSPI_CHCONF_DMAW         (1 << 14)
  80#define OMAP2_MCSPI_CHCONF_DMAR         (1 << 15)
  81#define OMAP2_MCSPI_CHCONF_DPE0         (1 << 16)
  82#define OMAP2_MCSPI_CHCONF_DPE1         (1 << 17)
  83#define OMAP2_MCSPI_CHCONF_IS           (1 << 18)
  84#define OMAP2_MCSPI_CHCONF_TURBO        (1 << 19)
  85#define OMAP2_MCSPI_CHCONF_FORCE        (1 << 20)
  86
  87#define OMAP2_MCSPI_CHSTAT_RXS          (1 << 0)
  88#define OMAP2_MCSPI_CHSTAT_TXS          (1 << 1)
  89#define OMAP2_MCSPI_CHSTAT_EOT          (1 << 2)
  90
  91#define OMAP2_MCSPI_CHCTRL_EN           (1 << 0)
  92
  93
  94/* We have 2 DMA channels per CS, one for RX and one for TX */
  95struct omap2_mcspi_dma {
  96        int dma_tx_channel;
  97        int dma_rx_channel;
  98
  99        int dma_tx_sync_dev;
 100        int dma_rx_sync_dev;
 101
 102        struct completion dma_tx_completion;
 103        struct completion dma_rx_completion;
 104};
 105
 106/* use PIO for small transfers, avoiding DMA setup/teardown overhead and
 107 * cache operations; better heuristics consider wordsize and bitrate.
 108 */
 109#define DMA_MIN_BYTES                   8
 110
 111
 112struct omap2_mcspi {
 113        struct work_struct      work;
 114        /* lock protects queue and registers */
 115        spinlock_t              lock;
 116        struct list_head        msg_queue;
 117        struct spi_master       *master;
 118        struct clk              *ick;
 119        struct clk              *fck;
 120        /* Virtual base address of the controller */
 121        void __iomem            *base;
 122        /* SPI1 has 4 channels, while SPI2 has 2 */
 123        struct omap2_mcspi_dma  *dma_channels;
 124};
 125
 126struct omap2_mcspi_cs {
 127        void __iomem            *base;
 128        int                     word_len;
 129};
 130
 131static struct workqueue_struct *omap2_mcspi_wq;
 132
 133#define MOD_REG_BIT(val, mask, set) do { \
 134        if (set) \
 135                val |= mask; \
 136        else \
 137                val &= ~mask; \
 138} while (0)
 139
 140static inline void mcspi_write_reg(struct spi_master *master,
 141                int idx, u32 val)
 142{
 143        struct omap2_mcspi *mcspi = spi_master_get_devdata(master);
 144
 145        __raw_writel(val, mcspi->base + idx);
 146}
 147
 148static inline u32 mcspi_read_reg(struct spi_master *master, int idx)
 149{
 150        struct omap2_mcspi *mcspi = spi_master_get_devdata(master);
 151
 152        return __raw_readl(mcspi->base + idx);
 153}
 154
 155static inline void mcspi_write_cs_reg(const struct spi_device *spi,
 156                int idx, u32 val)
 157{
 158        struct omap2_mcspi_cs   *cs = spi->controller_state;
 159
 160        __raw_writel(val, cs->base +  idx);
 161}
 162
 163static inline u32 mcspi_read_cs_reg(const struct spi_device *spi, int idx)
 164{
 165        struct omap2_mcspi_cs   *cs = spi->controller_state;
 166
 167        return __raw_readl(cs->base + idx);
 168}
 169
 170static void omap2_mcspi_set_dma_req(const struct spi_device *spi,
 171                int is_read, int enable)
 172{
 173        u32 l, rw;
 174
 175        l = mcspi_read_cs_reg(spi, OMAP2_MCSPI_CHCONF0);
 176
 177        if (is_read) /* 1 is read, 0 write */
 178                rw = OMAP2_MCSPI_CHCONF_DMAR;
 179        else
 180                rw = OMAP2_MCSPI_CHCONF_DMAW;
 181
 182        MOD_REG_BIT(l, rw, enable);
 183        mcspi_write_cs_reg(spi, OMAP2_MCSPI_CHCONF0, l);
 184}
 185
 186static void omap2_mcspi_set_enable(const struct spi_device *spi, int enable)
 187{
 188        u32 l;
 189
 190        l = enable ? OMAP2_MCSPI_CHCTRL_EN : 0;
 191        mcspi_write_cs_reg(spi, OMAP2_MCSPI_CHCTRL0, l);
 192}
 193
 194static void omap2_mcspi_force_cs(struct spi_device *spi, int cs_active)
 195{
 196        u32 l;
 197
 198        l = mcspi_read_cs_reg(spi, OMAP2_MCSPI_CHCONF0);
 199        MOD_REG_BIT(l, OMAP2_MCSPI_CHCONF_FORCE, cs_active);
 200        mcspi_write_cs_reg(spi, OMAP2_MCSPI_CHCONF0, l);
 201}
 202
 203static void omap2_mcspi_set_master_mode(struct spi_master *master)
 204{
 205        u32 l;
 206
 207        /* setup when switching from (reset default) slave mode
 208         * to single-channel master mode
 209         */
 210        l = mcspi_read_reg(master, OMAP2_MCSPI_MODULCTRL);
 211        MOD_REG_BIT(l, OMAP2_MCSPI_MODULCTRL_STEST, 0);
 212        MOD_REG_BIT(l, OMAP2_MCSPI_MODULCTRL_MS, 0);
 213        MOD_REG_BIT(l, OMAP2_MCSPI_MODULCTRL_SINGLE, 1);
 214        mcspi_write_reg(master, OMAP2_MCSPI_MODULCTRL, l);
 215}
 216
 217static unsigned
 218omap2_mcspi_txrx_dma(struct spi_device *spi, struct spi_transfer *xfer)
 219{
 220        struct omap2_mcspi      *mcspi;
 221        struct omap2_mcspi_cs   *cs = spi->controller_state;
 222        struct omap2_mcspi_dma  *mcspi_dma;
 223        unsigned int            count, c;
 224        unsigned long           base, tx_reg, rx_reg;
 225        int                     word_len, data_type, element_count;
 226        u8                      * rx;
 227        const u8                * tx;
 228
 229        mcspi = spi_master_get_devdata(spi->master);
 230        mcspi_dma = &mcspi->dma_channels[spi->chip_select];
 231
 232        count = xfer->len;
 233        c = count;
 234        word_len = cs->word_len;
 235
 236        base = (unsigned long) io_v2p(cs->base);
 237        tx_reg = base + OMAP2_MCSPI_TX0;
 238        rx_reg = base + OMAP2_MCSPI_RX0;
 239        rx = xfer->rx_buf;
 240        tx = xfer->tx_buf;
 241
 242        if (word_len <= 8) {
 243                data_type = OMAP_DMA_DATA_TYPE_S8;
 244                element_count = count;
 245        } else if (word_len <= 16) {
 246                data_type = OMAP_DMA_DATA_TYPE_S16;
 247                element_count = count >> 1;
 248        } else /* word_len <= 32 */ {
 249                data_type = OMAP_DMA_DATA_TYPE_S32;
 250                element_count = count >> 2;
 251        }
 252
 253        if (tx != NULL) {
 254                omap_set_dma_transfer_params(mcspi_dma->dma_tx_channel,
 255                                data_type, element_count, 1,
 256                                OMAP_DMA_SYNC_ELEMENT,
 257                                mcspi_dma->dma_tx_sync_dev, 0);
 258
 259                omap_set_dma_dest_params(mcspi_dma->dma_tx_channel, 0,
 260                                OMAP_DMA_AMODE_CONSTANT,
 261                                tx_reg, 0, 0);
 262
 263                omap_set_dma_src_params(mcspi_dma->dma_tx_channel, 0,
 264                                OMAP_DMA_AMODE_POST_INC,
 265                                xfer->tx_dma, 0, 0);
 266        }
 267
 268        if (rx != NULL) {
 269                omap_set_dma_transfer_params(mcspi_dma->dma_rx_channel,
 270                                data_type, element_count, 1,
 271                                OMAP_DMA_SYNC_ELEMENT,
 272                                mcspi_dma->dma_rx_sync_dev, 1);
 273
 274                omap_set_dma_src_params(mcspi_dma->dma_rx_channel, 0,
 275                                OMAP_DMA_AMODE_CONSTANT,
 276                                rx_reg, 0, 0);
 277
 278                omap_set_dma_dest_params(mcspi_dma->dma_rx_channel, 0,
 279                                OMAP_DMA_AMODE_POST_INC,
 280                                xfer->rx_dma, 0, 0);
 281        }
 282
 283        if (tx != NULL) {
 284                omap_start_dma(mcspi_dma->dma_tx_channel);
 285                omap2_mcspi_set_dma_req(spi, 0, 1);
 286        }
 287
 288        if (rx != NULL) {
 289                omap_start_dma(mcspi_dma->dma_rx_channel);
 290                omap2_mcspi_set_dma_req(spi, 1, 1);
 291        }
 292
 293        if (tx != NULL) {
 294                wait_for_completion(&mcspi_dma->dma_tx_completion);
 295                dma_unmap_single(NULL, xfer->tx_dma, count, DMA_TO_DEVICE);
 296        }
 297
 298        if (rx != NULL) {
 299                wait_for_completion(&mcspi_dma->dma_rx_completion);
 300                dma_unmap_single(NULL, xfer->rx_dma, count, DMA_FROM_DEVICE);
 301        }
 302        return count;
 303}
 304
 305static int mcspi_wait_for_reg_bit(void __iomem *reg, unsigned long bit)
 306{
 307        unsigned long timeout;
 308
 309        timeout = jiffies + msecs_to_jiffies(1000);
 310        while (!(__raw_readl(reg) & bit)) {
 311                if (time_after(jiffies, timeout))
 312                        return -1;
 313                cpu_relax();
 314        }
 315        return 0;
 316}
 317
 318static unsigned
 319omap2_mcspi_txrx_pio(struct spi_device *spi, struct spi_transfer *xfer)
 320{
 321        struct omap2_mcspi      *mcspi;
 322        struct omap2_mcspi_cs   *cs = spi->controller_state;
 323        unsigned int            count, c;
 324        u32                     l;
 325        void __iomem            *base = cs->base;
 326        void __iomem            *tx_reg;
 327        void __iomem            *rx_reg;
 328        void __iomem            *chstat_reg;
 329        int                     word_len;
 330
 331        mcspi = spi_master_get_devdata(spi->master);
 332        count = xfer->len;
 333        c = count;
 334        word_len = cs->word_len;
 335
 336        l = mcspi_read_cs_reg(spi, OMAP2_MCSPI_CHCONF0);
 337        l &= ~OMAP2_MCSPI_CHCONF_TRM_MASK;
 338
 339        /* We store the pre-calculated register addresses on stack to speed
 340         * up the transfer loop. */
 341        tx_reg          = base + OMAP2_MCSPI_TX0;
 342        rx_reg          = base + OMAP2_MCSPI_RX0;
 343        chstat_reg      = base + OMAP2_MCSPI_CHSTAT0;
 344
 345        if (word_len <= 8) {
 346                u8              *rx;
 347                const u8        *tx;
 348
 349                rx = xfer->rx_buf;
 350                tx = xfer->tx_buf;
 351
 352                do {
 353                        c -= 1;
 354                        if (tx != NULL) {
 355                                if (mcspi_wait_for_reg_bit(chstat_reg,
 356                                                OMAP2_MCSPI_CHSTAT_TXS) < 0) {
 357                                        dev_err(&spi->dev, "TXS timed out\n");
 358                                        goto out;
 359                                }
 360#ifdef VERBOSE
 361                                dev_dbg(&spi->dev, "write-%d %02x\n",
 362                                                word_len, *tx);
 363#endif
 364                                __raw_writel(*tx++, tx_reg);
 365                        }
 366                        if (rx != NULL) {
 367                                if (mcspi_wait_for_reg_bit(chstat_reg,
 368                                                OMAP2_MCSPI_CHSTAT_RXS) < 0) {
 369                                        dev_err(&spi->dev, "RXS timed out\n");
 370                                        goto out;
 371                                }
 372                                /* prevent last RX_ONLY read from triggering
 373                                 * more word i/o: switch to rx+tx
 374                                 */
 375                                if (c == 0 && tx == NULL)
 376                                        mcspi_write_cs_reg(spi,
 377                                                        OMAP2_MCSPI_CHCONF0, l);
 378                                *rx++ = __raw_readl(rx_reg);
 379#ifdef VERBOSE
 380                                dev_dbg(&spi->dev, "read-%d %02x\n",
 381                                                word_len, *(rx - 1));
 382#endif
 383                        }
 384                } while (c);
 385        } else if (word_len <= 16) {
 386                u16             *rx;
 387                const u16       *tx;
 388
 389                rx = xfer->rx_buf;
 390                tx = xfer->tx_buf;
 391                do {
 392                        c -= 2;
 393                        if (tx != NULL) {
 394                                if (mcspi_wait_for_reg_bit(chstat_reg,
 395                                                OMAP2_MCSPI_CHSTAT_TXS) < 0) {
 396                                        dev_err(&spi->dev, "TXS timed out\n");
 397                                        goto out;
 398                                }
 399#ifdef VERBOSE
 400                                dev_dbg(&spi->dev, "write-%d %04x\n",
 401                                                word_len, *tx);
 402#endif
 403                                __raw_writel(*tx++, tx_reg);
 404                        }
 405                        if (rx != NULL) {
 406                                if (mcspi_wait_for_reg_bit(chstat_reg,
 407                                                OMAP2_MCSPI_CHSTAT_RXS) < 0) {
 408                                        dev_err(&spi->dev, "RXS timed out\n");
 409                                        goto out;
 410                                }
 411                                /* prevent last RX_ONLY read from triggering
 412                                 * more word i/o: switch to rx+tx
 413                                 */
 414                                if (c == 0 && tx == NULL)
 415                                        mcspi_write_cs_reg(spi,
 416                                                        OMAP2_MCSPI_CHCONF0, l);
 417                                *rx++ = __raw_readl(rx_reg);
 418#ifdef VERBOSE
 419                                dev_dbg(&spi->dev, "read-%d %04x\n",
 420                                                word_len, *(rx - 1));
 421#endif
 422                        }
 423                } while (c);
 424        } else if (word_len <= 32) {
 425                u32             *rx;
 426                const u32       *tx;
 427
 428                rx = xfer->rx_buf;
 429                tx = xfer->tx_buf;
 430                do {
 431                        c -= 4;
 432                        if (tx != NULL) {
 433                                if (mcspi_wait_for_reg_bit(chstat_reg,
 434                                                OMAP2_MCSPI_CHSTAT_TXS) < 0) {
 435                                        dev_err(&spi->dev, "TXS timed out\n");
 436                                        goto out;
 437                                }
 438#ifdef VERBOSE
 439                                dev_dbg(&spi->dev, "write-%d %04x\n",
 440                                                word_len, *tx);
 441#endif
 442                                __raw_writel(*tx++, tx_reg);
 443                        }
 444                        if (rx != NULL) {
 445                                if (mcspi_wait_for_reg_bit(chstat_reg,
 446                                                OMAP2_MCSPI_CHSTAT_RXS) < 0) {
 447                                        dev_err(&spi->dev, "RXS timed out\n");
 448                                        goto out;
 449                                }
 450                                /* prevent last RX_ONLY read from triggering
 451                                 * more word i/o: switch to rx+tx
 452                                 */
 453                                if (c == 0 && tx == NULL)
 454                                        mcspi_write_cs_reg(spi,
 455                                                        OMAP2_MCSPI_CHCONF0, l);
 456                                *rx++ = __raw_readl(rx_reg);
 457#ifdef VERBOSE
 458                                dev_dbg(&spi->dev, "read-%d %04x\n",
 459                                                word_len, *(rx - 1));
 460#endif
 461                        }
 462                } while (c);
 463        }
 464
 465        /* for TX_ONLY mode, be sure all words have shifted out */
 466        if (xfer->rx_buf == NULL) {
 467                if (mcspi_wait_for_reg_bit(chstat_reg,
 468                                OMAP2_MCSPI_CHSTAT_TXS) < 0) {
 469                        dev_err(&spi->dev, "TXS timed out\n");
 470                } else if (mcspi_wait_for_reg_bit(chstat_reg,
 471                                OMAP2_MCSPI_CHSTAT_EOT) < 0)
 472                        dev_err(&spi->dev, "EOT timed out\n");
 473        }
 474out:
 475        return count - c;
 476}
 477
 478/* called only when no transfer is active to this device */
 479static int omap2_mcspi_setup_transfer(struct spi_device *spi,
 480                struct spi_transfer *t)
 481{
 482        struct omap2_mcspi_cs *cs = spi->controller_state;
 483        struct omap2_mcspi *mcspi;
 484        u32 l = 0, div = 0;
 485        u8 word_len = spi->bits_per_word;
 486
 487        mcspi = spi_master_get_devdata(spi->master);
 488
 489        if (t != NULL && t->bits_per_word)
 490                word_len = t->bits_per_word;
 491
 492        cs->word_len = word_len;
 493
 494        if (spi->max_speed_hz) {
 495                while (div <= 15 && (OMAP2_MCSPI_MAX_FREQ / (1 << div))
 496                                        > spi->max_speed_hz)
 497                        div++;
 498        } else
 499                div = 15;
 500
 501        l = mcspi_read_cs_reg(spi, OMAP2_MCSPI_CHCONF0);
 502
 503        /* standard 4-wire master mode:  SCK, MOSI/out, MISO/in, nCS
 504         * REVISIT: this controller could support SPI_3WIRE mode.
 505         */
 506        l &= ~(OMAP2_MCSPI_CHCONF_IS|OMAP2_MCSPI_CHCONF_DPE1);
 507        l |= OMAP2_MCSPI_CHCONF_DPE0;
 508
 509        /* wordlength */
 510        l &= ~OMAP2_MCSPI_CHCONF_WL_MASK;
 511        l |= (word_len - 1) << 7;
 512
 513        /* set chipselect polarity; manage with FORCE */
 514        if (!(spi->mode & SPI_CS_HIGH))
 515                l |= OMAP2_MCSPI_CHCONF_EPOL;   /* active-low; normal */
 516        else
 517                l &= ~OMAP2_MCSPI_CHCONF_EPOL;
 518
 519        /* set clock divisor */
 520        l &= ~OMAP2_MCSPI_CHCONF_CLKD_MASK;
 521        l |= div << 2;
 522
 523        /* set SPI mode 0..3 */
 524        if (spi->mode & SPI_CPOL)
 525                l |= OMAP2_MCSPI_CHCONF_POL;
 526        else
 527                l &= ~OMAP2_MCSPI_CHCONF_POL;
 528        if (spi->mode & SPI_CPHA)
 529                l |= OMAP2_MCSPI_CHCONF_PHA;
 530        else
 531                l &= ~OMAP2_MCSPI_CHCONF_PHA;
 532
 533        mcspi_write_cs_reg(spi, OMAP2_MCSPI_CHCONF0, l);
 534
 535        dev_dbg(&spi->dev, "setup: speed %d, sample %s edge, clk %s\n",
 536                        OMAP2_MCSPI_MAX_FREQ / (1 << div),
 537                        (spi->mode & SPI_CPHA) ? "trailing" : "leading",
 538                        (spi->mode & SPI_CPOL) ? "inverted" : "normal");
 539
 540        return 0;
 541}
 542
 543static void omap2_mcspi_dma_rx_callback(int lch, u16 ch_status, void *data)
 544{
 545        struct spi_device       *spi = data;
 546        struct omap2_mcspi      *mcspi;
 547        struct omap2_mcspi_dma  *mcspi_dma;
 548
 549        mcspi = spi_master_get_devdata(spi->master);
 550        mcspi_dma = &(mcspi->dma_channels[spi->chip_select]);
 551
 552        complete(&mcspi_dma->dma_rx_completion);
 553
 554        /* We must disable the DMA RX request */
 555        omap2_mcspi_set_dma_req(spi, 1, 0);
 556}
 557
 558static void omap2_mcspi_dma_tx_callback(int lch, u16 ch_status, void *data)
 559{
 560        struct spi_device       *spi = data;
 561        struct omap2_mcspi      *mcspi;
 562        struct omap2_mcspi_dma  *mcspi_dma;
 563
 564        mcspi = spi_master_get_devdata(spi->master);
 565        mcspi_dma = &(mcspi->dma_channels[spi->chip_select]);
 566
 567        complete(&mcspi_dma->dma_tx_completion);
 568
 569        /* We must disable the DMA TX request */
 570        omap2_mcspi_set_dma_req(spi, 0, 0);
 571}
 572
 573static int omap2_mcspi_request_dma(struct spi_device *spi)
 574{
 575        struct spi_master       *master = spi->master;
 576        struct omap2_mcspi      *mcspi;
 577        struct omap2_mcspi_dma  *mcspi_dma;
 578
 579        mcspi = spi_master_get_devdata(master);
 580        mcspi_dma = mcspi->dma_channels + spi->chip_select;
 581
 582        if (omap_request_dma(mcspi_dma->dma_rx_sync_dev, "McSPI RX",
 583                        omap2_mcspi_dma_rx_callback, spi,
 584                        &mcspi_dma->dma_rx_channel)) {
 585                dev_err(&spi->dev, "no RX DMA channel for McSPI\n");
 586                return -EAGAIN;
 587        }
 588
 589        if (omap_request_dma(mcspi_dma->dma_tx_sync_dev, "McSPI TX",
 590                        omap2_mcspi_dma_tx_callback, spi,
 591                        &mcspi_dma->dma_tx_channel)) {
 592                omap_free_dma(mcspi_dma->dma_rx_channel);
 593                mcspi_dma->dma_rx_channel = -1;
 594                dev_err(&spi->dev, "no TX DMA channel for McSPI\n");
 595                return -EAGAIN;
 596        }
 597
 598        init_completion(&mcspi_dma->dma_rx_completion);
 599        init_completion(&mcspi_dma->dma_tx_completion);
 600
 601        return 0;
 602}
 603
 604/* the spi->mode bits understood by this driver: */
 605#define MODEBITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH)
 606
 607static int omap2_mcspi_setup(struct spi_device *spi)
 608{
 609        int                     ret;
 610        struct omap2_mcspi      *mcspi;
 611        struct omap2_mcspi_dma  *mcspi_dma;
 612        struct omap2_mcspi_cs   *cs = spi->controller_state;
 613
 614        if (spi->mode & ~MODEBITS) {
 615                dev_dbg(&spi->dev, "setup: unsupported mode bits %x\n",
 616                        spi->mode & ~MODEBITS);
 617                return -EINVAL;
 618        }
 619
 620        if (spi->bits_per_word == 0)
 621                spi->bits_per_word = 8;
 622        else if (spi->bits_per_word < 4 || spi->bits_per_word > 32) {
 623                dev_dbg(&spi->dev, "setup: unsupported %d bit words\n",
 624                        spi->bits_per_word);
 625                return -EINVAL;
 626        }
 627
 628        mcspi = spi_master_get_devdata(spi->master);
 629        mcspi_dma = &mcspi->dma_channels[spi->chip_select];
 630
 631        if (!cs) {
 632                cs = kzalloc(sizeof *cs, GFP_KERNEL);
 633                if (!cs)
 634                        return -ENOMEM;
 635                cs->base = mcspi->base + spi->chip_select * 0x14;
 636                spi->controller_state = cs;
 637        }
 638
 639        if (mcspi_dma->dma_rx_channel == -1
 640                        || mcspi_dma->dma_tx_channel == -1) {
 641                ret = omap2_mcspi_request_dma(spi);
 642                if (ret < 0)
 643                        return ret;
 644        }
 645
 646        clk_enable(mcspi->ick);
 647        clk_enable(mcspi->fck);
 648        ret = omap2_mcspi_setup_transfer(spi, NULL);
 649        clk_disable(mcspi->fck);
 650        clk_disable(mcspi->ick);
 651
 652        return ret;
 653}
 654
 655static void omap2_mcspi_cleanup(struct spi_device *spi)
 656{
 657        struct omap2_mcspi      *mcspi;
 658        struct omap2_mcspi_dma  *mcspi_dma;
 659
 660        mcspi = spi_master_get_devdata(spi->master);
 661        mcspi_dma = &mcspi->dma_channels[spi->chip_select];
 662
 663        kfree(spi->controller_state);
 664
 665        if (mcspi_dma->dma_rx_channel != -1) {
 666                omap_free_dma(mcspi_dma->dma_rx_channel);
 667                mcspi_dma->dma_rx_channel = -1;
 668        }
 669        if (mcspi_dma->dma_tx_channel != -1) {
 670                omap_free_dma(mcspi_dma->dma_tx_channel);
 671                mcspi_dma->dma_tx_channel = -1;
 672        }
 673}
 674
 675static void omap2_mcspi_work(struct work_struct *work)
 676{
 677        struct omap2_mcspi      *mcspi;
 678
 679        mcspi = container_of(work, struct omap2_mcspi, work);
 680        spin_lock_irq(&mcspi->lock);
 681
 682        clk_enable(mcspi->ick);
 683        clk_enable(mcspi->fck);
 684
 685        /* We only enable one channel at a time -- the one whose message is
 686         * at the head of the queue -- although this controller would gladly
 687         * arbitrate among multiple channels.  This corresponds to "single
 688         * channel" master mode.  As a side effect, we need to manage the
 689         * chipselect with the FORCE bit ... CS != channel enable.
 690         */
 691        while (!list_empty(&mcspi->msg_queue)) {
 692                struct spi_message              *m;
 693                struct spi_device               *spi;
 694                struct spi_transfer             *t = NULL;
 695                int                             cs_active = 0;
 696                struct omap2_mcspi_cs           *cs;
 697                int                             par_override = 0;
 698                int                             status = 0;
 699                u32                             chconf;
 700
 701                m = container_of(mcspi->msg_queue.next, struct spi_message,
 702                                 queue);
 703
 704                list_del_init(&m->queue);
 705                spin_unlock_irq(&mcspi->lock);
 706
 707                spi = m->spi;
 708                cs = spi->controller_state;
 709
 710                omap2_mcspi_set_enable(spi, 1);
 711                list_for_each_entry(t, &m->transfers, transfer_list) {
 712                        if (t->tx_buf == NULL && t->rx_buf == NULL && t->len) {
 713                                status = -EINVAL;
 714                                break;
 715                        }
 716                        if (par_override || t->speed_hz || t->bits_per_word) {
 717                                par_override = 1;
 718                                status = omap2_mcspi_setup_transfer(spi, t);
 719                                if (status < 0)
 720                                        break;
 721                                if (!t->speed_hz && !t->bits_per_word)
 722                                        par_override = 0;
 723                        }
 724
 725                        if (!cs_active) {
 726                                omap2_mcspi_force_cs(spi, 1);
 727                                cs_active = 1;
 728                        }
 729
 730                        chconf = mcspi_read_cs_reg(spi, OMAP2_MCSPI_CHCONF0);
 731                        chconf &= ~OMAP2_MCSPI_CHCONF_TRM_MASK;
 732                        if (t->tx_buf == NULL)
 733                                chconf |= OMAP2_MCSPI_CHCONF_TRM_RX_ONLY;
 734                        else if (t->rx_buf == NULL)
 735                                chconf |= OMAP2_MCSPI_CHCONF_TRM_TX_ONLY;
 736                        mcspi_write_cs_reg(spi, OMAP2_MCSPI_CHCONF0, chconf);
 737
 738                        if (t->len) {
 739                                unsigned        count;
 740
 741                                /* RX_ONLY mode needs dummy data in TX reg */
 742                                if (t->tx_buf == NULL)
 743                                        __raw_writel(0, cs->base
 744                                                        + OMAP2_MCSPI_TX0);
 745
 746                                if (m->is_dma_mapped || t->len >= DMA_MIN_BYTES)
 747                                        count = omap2_mcspi_txrx_dma(spi, t);
 748                                else
 749                                        count = omap2_mcspi_txrx_pio(spi, t);
 750                                m->actual_length += count;
 751
 752                                if (count != t->len) {
 753                                        status = -EIO;
 754                                        break;
 755                                }
 756                        }
 757
 758                        if (t->delay_usecs)
 759                                udelay(t->delay_usecs);
 760
 761                        /* ignore the "leave it on after last xfer" hint */
 762                        if (t->cs_change) {
 763                                omap2_mcspi_force_cs(spi, 0);
 764                                cs_active = 0;
 765                        }
 766                }
 767
 768                /* Restore defaults if they were overriden */
 769                if (par_override) {
 770                        par_override = 0;
 771                        status = omap2_mcspi_setup_transfer(spi, NULL);
 772                }
 773
 774                if (cs_active)
 775                        omap2_mcspi_force_cs(spi, 0);
 776
 777                omap2_mcspi_set_enable(spi, 0);
 778
 779                m->status = status;
 780                m->complete(m->context);
 781
 782                spin_lock_irq(&mcspi->lock);
 783        }
 784
 785        clk_disable(mcspi->fck);
 786        clk_disable(mcspi->ick);
 787
 788        spin_unlock_irq(&mcspi->lock);
 789}
 790
 791static int omap2_mcspi_transfer(struct spi_device *spi, struct spi_message *m)
 792{
 793        struct omap2_mcspi      *mcspi;
 794        unsigned long           flags;
 795        struct spi_transfer     *t;
 796
 797        m->actual_length = 0;
 798        m->status = 0;
 799
 800        /* reject invalid messages and transfers */
 801        if (list_empty(&m->transfers) || !m->complete)
 802                return -EINVAL;
 803        list_for_each_entry(t, &m->transfers, transfer_list) {
 804                const void      *tx_buf = t->tx_buf;
 805                void            *rx_buf = t->rx_buf;
 806                unsigned        len = t->len;
 807
 808                if (t->speed_hz > OMAP2_MCSPI_MAX_FREQ
 809                                || (len && !(rx_buf || tx_buf))
 810                                || (t->bits_per_word &&
 811                                        (  t->bits_per_word < 4
 812                                        || t->bits_per_word > 32))) {
 813                        dev_dbg(&spi->dev, "transfer: %d Hz, %d %s%s, %d bpw\n",
 814                                        t->speed_hz,
 815                                        len,
 816                                        tx_buf ? "tx" : "",
 817                                        rx_buf ? "rx" : "",
 818                                        t->bits_per_word);
 819                        return -EINVAL;
 820                }
 821                if (t->speed_hz && t->speed_hz < OMAP2_MCSPI_MAX_FREQ/(1<<16)) {
 822                        dev_dbg(&spi->dev, "%d Hz max exceeds %d\n",
 823                                        t->speed_hz,
 824                                        OMAP2_MCSPI_MAX_FREQ/(1<<16));
 825                        return -EINVAL;
 826                }
 827
 828                if (m->is_dma_mapped || len < DMA_MIN_BYTES)
 829                        continue;
 830
 831                /* Do DMA mapping "early" for better error reporting and
 832                 * dcache use.  Note that if dma_unmap_single() ever starts
 833                 * to do real work on ARM, we'd need to clean up mappings
 834                 * for previous transfers on *ALL* exits of this loop...
 835                 */
 836                if (tx_buf != NULL) {
 837                        t->tx_dma = dma_map_single(&spi->dev, (void *) tx_buf,
 838                                        len, DMA_TO_DEVICE);
 839                        if (dma_mapping_error(t->tx_dma)) {
 840                                dev_dbg(&spi->dev, "dma %cX %d bytes error\n",
 841                                                'T', len);
 842                                return -EINVAL;
 843                        }
 844                }
 845                if (rx_buf != NULL) {
 846                        t->rx_dma = dma_map_single(&spi->dev, rx_buf, t->len,
 847                                        DMA_FROM_DEVICE);
 848                        if (dma_mapping_error(t->rx_dma)) {
 849                                dev_dbg(&spi->dev, "dma %cX %d bytes error\n",
 850                                                'R', len);
 851                                if (tx_buf != NULL)
 852                                        dma_unmap_single(NULL, t->tx_dma,
 853                                                        len, DMA_TO_DEVICE);
 854                                return -EINVAL;
 855                        }
 856                }
 857        }
 858
 859        mcspi = spi_master_get_devdata(spi->master);
 860
 861        spin_lock_irqsave(&mcspi->lock, flags);
 862        list_add_tail(&m->queue, &mcspi->msg_queue);
 863        queue_work(omap2_mcspi_wq, &mcspi->work);
 864        spin_unlock_irqrestore(&mcspi->lock, flags);
 865
 866        return 0;
 867}
 868
 869static int __init omap2_mcspi_reset(struct omap2_mcspi *mcspi)
 870{
 871        struct spi_master       *master = mcspi->master;
 872        u32                     tmp;
 873
 874        clk_enable(mcspi->ick);
 875        clk_enable(mcspi->fck);
 876
 877        mcspi_write_reg(master, OMAP2_MCSPI_SYSCONFIG,
 878                        OMAP2_MCSPI_SYSCONFIG_SOFTRESET);
 879        do {
 880                tmp = mcspi_read_reg(master, OMAP2_MCSPI_SYSSTATUS);
 881        } while (!(tmp & OMAP2_MCSPI_SYSSTATUS_RESETDONE));
 882
 883        mcspi_write_reg(master, OMAP2_MCSPI_SYSCONFIG,
 884                        /* (3 << 8) | (2 << 3) | */
 885                        OMAP2_MCSPI_SYSCONFIG_AUTOIDLE);
 886
 887        omap2_mcspi_set_master_mode(master);
 888
 889        clk_disable(mcspi->fck);
 890        clk_disable(mcspi->ick);
 891        return 0;
 892}
 893
 894static u8 __initdata spi1_rxdma_id [] = {
 895        OMAP24XX_DMA_SPI1_RX0,
 896        OMAP24XX_DMA_SPI1_RX1,
 897        OMAP24XX_DMA_SPI1_RX2,
 898        OMAP24XX_DMA_SPI1_RX3,
 899};
 900
 901static u8 __initdata spi1_txdma_id [] = {
 902        OMAP24XX_DMA_SPI1_TX0,
 903        OMAP24XX_DMA_SPI1_TX1,
 904        OMAP24XX_DMA_SPI1_TX2,
 905        OMAP24XX_DMA_SPI1_TX3,
 906};
 907
 908static u8 __initdata spi2_rxdma_id[] = {
 909        OMAP24XX_DMA_SPI2_RX0,
 910        OMAP24XX_DMA_SPI2_RX1,
 911};
 912
 913static u8 __initdata spi2_txdma_id[] = {
 914        OMAP24XX_DMA_SPI2_TX0,
 915        OMAP24XX_DMA_SPI2_TX1,
 916};
 917
 918static int __init omap2_mcspi_probe(struct platform_device *pdev)
 919{
 920        struct spi_master       *master;
 921        struct omap2_mcspi      *mcspi;
 922        struct resource         *r;
 923        int                     status = 0, i;
 924        const u8                *rxdma_id, *txdma_id;
 925        unsigned                num_chipselect;
 926
 927        switch (pdev->id) {
 928        case 1:
 929                rxdma_id = spi1_rxdma_id;
 930                txdma_id = spi1_txdma_id;
 931                num_chipselect = 4;
 932                break;
 933        case 2:
 934                rxdma_id = spi2_rxdma_id;
 935                txdma_id = spi2_txdma_id;
 936                num_chipselect = 2;
 937                break;
 938        /* REVISIT omap2430 has a third McSPI ... */
 939        default:
 940                return -EINVAL;
 941        }
 942
 943        master = spi_alloc_master(&pdev->dev, sizeof *mcspi);
 944        if (master == NULL) {
 945                dev_dbg(&pdev->dev, "master allocation failed\n");
 946                return -ENOMEM;
 947        }
 948
 949        if (pdev->id != -1)
 950                master->bus_num = pdev->id;
 951
 952        master->setup = omap2_mcspi_setup;
 953        master->transfer = omap2_mcspi_transfer;
 954        master->cleanup = omap2_mcspi_cleanup;
 955        master->num_chipselect = num_chipselect;
 956
 957        dev_set_drvdata(&pdev->dev, master);
 958
 959        mcspi = spi_master_get_devdata(master);
 960        mcspi->master = master;
 961
 962        r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 963        if (r == NULL) {
 964                status = -ENODEV;
 965                goto err1;
 966        }
 967        if (!request_mem_region(r->start, (r->end - r->start) + 1,
 968                        pdev->dev.bus_id)) {
 969                status = -EBUSY;
 970                goto err1;
 971        }
 972
 973        mcspi->base = (void __iomem *) io_p2v(r->start);
 974
 975        INIT_WORK(&mcspi->work, omap2_mcspi_work);
 976
 977        spin_lock_init(&mcspi->lock);
 978        INIT_LIST_HEAD(&mcspi->msg_queue);
 979
 980        mcspi->ick = clk_get(&pdev->dev, "mcspi_ick");
 981        if (IS_ERR(mcspi->ick)) {
 982                dev_dbg(&pdev->dev, "can't get mcspi_ick\n");
 983                status = PTR_ERR(mcspi->ick);
 984                goto err1a;
 985        }
 986        mcspi->fck = clk_get(&pdev->dev, "mcspi_fck");
 987        if (IS_ERR(mcspi->fck)) {
 988                dev_dbg(&pdev->dev, "can't get mcspi_fck\n");
 989                status = PTR_ERR(mcspi->fck);
 990                goto err2;
 991        }
 992
 993        mcspi->dma_channels = kcalloc(master->num_chipselect,
 994                        sizeof(struct omap2_mcspi_dma),
 995                        GFP_KERNEL);
 996
 997        if (mcspi->dma_channels == NULL)
 998                goto err3;
 999
1000        for (i = 0; i < num_chipselect; i++) {
1001                mcspi->dma_channels[i].dma_rx_channel = -1;
1002                mcspi->dma_channels[i].dma_rx_sync_dev = rxdma_id[i];
1003                mcspi->dma_channels[i].dma_tx_channel = -1;
1004                mcspi->dma_channels[i].dma_tx_sync_dev = txdma_id[i];
1005        }
1006
1007        if (omap2_mcspi_reset(mcspi) < 0)
1008                goto err4;
1009
1010        status = spi_register_master(master);
1011        if (status < 0)
1012                goto err4;
1013
1014        return status;
1015
1016err4:
1017        kfree(mcspi->dma_channels);
1018err3:
1019        clk_put(mcspi->fck);
1020err2:
1021        clk_put(mcspi->ick);
1022err1a:
1023        release_mem_region(r->start, (r->end - r->start) + 1);
1024err1:
1025        spi_master_put(master);
1026        return status;
1027}
1028
1029static int __exit omap2_mcspi_remove(struct platform_device *pdev)
1030{
1031        struct spi_master       *master;
1032        struct omap2_mcspi      *mcspi;
1033        struct omap2_mcspi_dma  *dma_channels;
1034        struct resource         *r;
1035
1036        master = dev_get_drvdata(&pdev->dev);
1037        mcspi = spi_master_get_devdata(master);
1038        dma_channels = mcspi->dma_channels;
1039
1040        clk_put(mcspi->fck);
1041        clk_put(mcspi->ick);
1042
1043        r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1044        release_mem_region(r->start, (r->end - r->start) + 1);
1045
1046        spi_unregister_master(master);
1047        kfree(dma_channels);
1048
1049        return 0;
1050}
1051
1052static struct platform_driver omap2_mcspi_driver = {
1053        .driver = {
1054                .name =         "omap2_mcspi",
1055                .owner =        THIS_MODULE,
1056        },
1057        .remove =       __exit_p(omap2_mcspi_remove),
1058};
1059
1060
1061static int __init omap2_mcspi_init(void)
1062{
1063        omap2_mcspi_wq = create_singlethread_workqueue(
1064                                omap2_mcspi_driver.driver.name);
1065        if (omap2_mcspi_wq == NULL)
1066                return -1;
1067        return platform_driver_probe(&omap2_mcspi_driver, omap2_mcspi_probe);
1068}
1069subsys_initcall(omap2_mcspi_init);
1070
1071static void __exit omap2_mcspi_exit(void)
1072{
1073        platform_driver_unregister(&omap2_mcspi_driver);
1074
1075        destroy_workqueue(omap2_mcspi_wq);
1076}
1077module_exit(omap2_mcspi_exit);
1078
1079MODULE_LICENSE("GPL");
1080