LXR linux/drivers/spi/spi-fsl-espi.c

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * Freescale eSPI controller driver.
   4 *
   5 * Copyright 2010 Freescale Semiconductor, Inc.
   6 */
   7#include <linux/delay.h>
   8#include <linux/err.h>
   9#include <linux/fsl_devices.h>
  10#include <linux/interrupt.h>
  11#include <linux/module.h>
  12#include <linux/mm.h>
  13#include <linux/of.h>
  14#include <linux/of_address.h>
  15#include <linux/of_irq.h>
  16#include <linux/of_platform.h>
  17#include <linux/platform_device.h>
  18#include <linux/spi/spi.h>
  19#include <linux/pm_runtime.h>
  20#include <sysdev/fsl_soc.h>
  21
  22/* eSPI Controller registers */
  23#define ESPI_SPMODE     0x00    /* eSPI mode register */
  24#define ESPI_SPIE       0x04    /* eSPI event register */
  25#define ESPI_SPIM       0x08    /* eSPI mask register */
  26#define ESPI_SPCOM      0x0c    /* eSPI command register */
  27#define ESPI_SPITF      0x10    /* eSPI transmit FIFO access register*/
  28#define ESPI_SPIRF      0x14    /* eSPI receive FIFO access register*/
  29#define ESPI_SPMODE0    0x20    /* eSPI cs0 mode register */
  30
  31#define ESPI_SPMODEx(x) (ESPI_SPMODE0 + (x) * 4)
  32
  33/* eSPI Controller mode register definitions */
  34#define SPMODE_ENABLE           BIT(31)
  35#define SPMODE_LOOP             BIT(30)
  36#define SPMODE_TXTHR(x)         ((x) << 8)
  37#define SPMODE_RXTHR(x)         ((x) << 0)
  38
  39/* eSPI Controller CS mode register definitions */
  40#define CSMODE_CI_INACTIVEHIGH  BIT(31)
  41#define CSMODE_CP_BEGIN_EDGECLK BIT(30)
  42#define CSMODE_REV              BIT(29)
  43#define CSMODE_DIV16            BIT(28)
  44#define CSMODE_PM(x)            ((x) << 24)
  45#define CSMODE_POL_1            BIT(20)
  46#define CSMODE_LEN(x)           ((x) << 16)
  47#define CSMODE_BEF(x)           ((x) << 12)
  48#define CSMODE_AFT(x)           ((x) << 8)
  49#define CSMODE_CG(x)            ((x) << 3)
  50
  51#define FSL_ESPI_FIFO_SIZE      32
  52#define FSL_ESPI_RXTHR          15
  53
  54/* Default mode/csmode for eSPI controller */
  55#define SPMODE_INIT_VAL (SPMODE_TXTHR(4) | SPMODE_RXTHR(FSL_ESPI_RXTHR))
  56#define CSMODE_INIT_VAL (CSMODE_POL_1 | CSMODE_BEF(0) \
  57                | CSMODE_AFT(0) | CSMODE_CG(1))
  58
  59/* SPIE register values */
  60#define SPIE_RXCNT(reg)     ((reg >> 24) & 0x3F)
  61#define SPIE_TXCNT(reg)     ((reg >> 16) & 0x3F)
  62#define SPIE_TXE                BIT(15) /* TX FIFO empty */
  63#define SPIE_DON                BIT(14) /* TX done */
  64#define SPIE_RXT                BIT(13) /* RX FIFO threshold */
  65#define SPIE_RXF                BIT(12) /* RX FIFO full */
  66#define SPIE_TXT                BIT(11) /* TX FIFO threshold*/
  67#define SPIE_RNE                BIT(9)  /* RX FIFO not empty */
  68#define SPIE_TNF                BIT(8)  /* TX FIFO not full */
  69
  70/* SPIM register values */
  71#define SPIM_TXE                BIT(15) /* TX FIFO empty */
  72#define SPIM_DON                BIT(14) /* TX done */
  73#define SPIM_RXT                BIT(13) /* RX FIFO threshold */
  74#define SPIM_RXF                BIT(12) /* RX FIFO full */
  75#define SPIM_TXT                BIT(11) /* TX FIFO threshold*/
  76#define SPIM_RNE                BIT(9)  /* RX FIFO not empty */
  77#define SPIM_TNF                BIT(8)  /* TX FIFO not full */
  78
  79/* SPCOM register values */
  80#define SPCOM_CS(x)             ((x) << 30)
  81#define SPCOM_DO                BIT(28) /* Dual output */
  82#define SPCOM_TO                BIT(27) /* TX only */
  83#define SPCOM_RXSKIP(x)         ((x) << 16)
  84#define SPCOM_TRANLEN(x)        ((x) << 0)
  85
  86#define SPCOM_TRANLEN_MAX       0x10000 /* Max transaction length */
  87
  88#define AUTOSUSPEND_TIMEOUT 2000
  89
  90struct fsl_espi {
  91        struct device *dev;
  92        void __iomem *reg_base;
  93
  94        struct list_head *m_transfers;
  95        struct spi_transfer *tx_t;
  96        unsigned int tx_pos;
  97        bool tx_done;
  98        struct spi_transfer *rx_t;
  99        unsigned int rx_pos;
 100        bool rx_done;
 101
 102        bool swab;
 103        unsigned int rxskip;
 104
 105        spinlock_t lock;
 106
 107        u32 spibrg;             /* SPIBRG input clock */
 108
 109        struct completion done;
 110};
 111
 112struct fsl_espi_cs {
 113        u32 hw_mode;
 114};
 115
 116static inline u32 fsl_espi_read_reg(struct fsl_espi *espi, int offset)
 117{
 118        return ioread32be(espi->reg_base + offset);
 119}
 120
 121static inline u16 fsl_espi_read_reg16(struct fsl_espi *espi, int offset)
 122{
 123        return ioread16be(espi->reg_base + offset);
 124}
 125
 126static inline u8 fsl_espi_read_reg8(struct fsl_espi *espi, int offset)
 127{
 128        return ioread8(espi->reg_base + offset);
 129}
 130
 131static inline void fsl_espi_write_reg(struct fsl_espi *espi, int offset,
 132                                      u32 val)
 133{
 134        iowrite32be(val, espi->reg_base + offset);
 135}
 136
 137static inline void fsl_espi_write_reg16(struct fsl_espi *espi, int offset,
 138                                        u16 val)
 139{
 140        iowrite16be(val, espi->reg_base + offset);
 141}
 142
 143static inline void fsl_espi_write_reg8(struct fsl_espi *espi, int offset,
 144                                       u8 val)
 145{
 146        iowrite8(val, espi->reg_base + offset);
 147}
 148
 149static int fsl_espi_check_message(struct spi_message *m)
 150{
 151        struct fsl_espi *espi = spi_master_get_devdata(m->spi->master);
 152        struct spi_transfer *t, *first;
 153
 154        if (m->frame_length > SPCOM_TRANLEN_MAX) {
 155                dev_err(espi->dev, "message too long, size is %u bytes\n",
 156                        m->frame_length);
 157                return -EMSGSIZE;
 158        }
 159
 160        first = list_first_entry(&m->transfers, struct spi_transfer,
 161                                 transfer_list);
 162
 163        list_for_each_entry(t, &m->transfers, transfer_list) {
 164                if (first->bits_per_word != t->bits_per_word ||
 165                    first->speed_hz != t->speed_hz) {
 166                        dev_err(espi->dev, "bits_per_word/speed_hz should be the same for all transfers\n");
 167                        return -EINVAL;
 168                }
 169        }
 170
 171        /* ESPI supports MSB-first transfers for word size 8 / 16 only */
 172        if (!(m->spi->mode & SPI_LSB_FIRST) && first->bits_per_word != 8 &&
 173            first->bits_per_word != 16) {
 174                dev_err(espi->dev,
 175                        "MSB-first transfer not supported for wordsize %u\n",
 176                        first->bits_per_word);
 177                return -EINVAL;
 178        }
 179
 180        return 0;
 181}
 182
 183static unsigned int fsl_espi_check_rxskip_mode(struct spi_message *m)
 184{
 185        struct spi_transfer *t;
 186        unsigned int i = 0, rxskip = 0;
 187
 188        /*
 189         * prerequisites for ESPI rxskip mode:
 190         * - message has two transfers
 191         * - first transfer is a write and second is a read
 192         *
 193         * In addition the current low-level transfer mechanism requires
 194         * that the rxskip bytes fit into the TX FIFO. Else the transfer
 195         * would hang because after the first FSL_ESPI_FIFO_SIZE bytes
 196         * the TX FIFO isn't re-filled.
 197         */
 198        list_for_each_entry(t, &m->transfers, transfer_list) {
 199                if (i == 0) {
 200                        if (!t->tx_buf || t->rx_buf ||
 201                            t->len > FSL_ESPI_FIFO_SIZE)
 202                                return 0;
 203                        rxskip = t->len;
 204                } else if (i == 1) {
 205                        if (t->tx_buf || !t->rx_buf)
 206                                return 0;
 207                }
 208                i++;
 209        }
 210
 211        return i == 2 ? rxskip : 0;
 212}
 213
 214static void fsl_espi_fill_tx_fifo(struct fsl_espi *espi, u32 events)
 215{
 216        u32 tx_fifo_avail;
 217        unsigned int tx_left;
 218        const void *tx_buf;
 219
 220        /* if events is zero transfer has not started and tx fifo is empty */
 221        tx_fifo_avail = events ? SPIE_TXCNT(events) :  FSL_ESPI_FIFO_SIZE;
 222start:
 223        tx_left = espi->tx_t->len - espi->tx_pos;
 224        tx_buf = espi->tx_t->tx_buf;
 225        while (tx_fifo_avail >= min(4U, tx_left) && tx_left) {
 226                if (tx_left >= 4) {
 227                        if (!tx_buf)
 228                                fsl_espi_write_reg(espi, ESPI_SPITF, 0);
 229                        else if (espi->swab)
 230                                fsl_espi_write_reg(espi, ESPI_SPITF,
 231                                        swahb32p(tx_buf + espi->tx_pos));
 232                        else
 233                                fsl_espi_write_reg(espi, ESPI_SPITF,
 234                                        *(u32 *)(tx_buf + espi->tx_pos));
 235                        espi->tx_pos += 4;
 236                        tx_left -= 4;
 237                        tx_fifo_avail -= 4;
 238                } else if (tx_left >= 2 && tx_buf && espi->swab) {
 239                        fsl_espi_write_reg16(espi, ESPI_SPITF,
 240                                        swab16p(tx_buf + espi->tx_pos));
 241                        espi->tx_pos += 2;
 242                        tx_left -= 2;
 243                        tx_fifo_avail -= 2;
 244                } else {
 245                        if (!tx_buf)
 246                                fsl_espi_write_reg8(espi, ESPI_SPITF, 0);
 247                        else
 248                                fsl_espi_write_reg8(espi, ESPI_SPITF,
 249                                        *(u8 *)(tx_buf + espi->tx_pos));
 250                        espi->tx_pos += 1;
 251                        tx_left -= 1;
 252                        tx_fifo_avail -= 1;
 253                }
 254        }
 255
 256        if (!tx_left) {
 257                /* Last transfer finished, in rxskip mode only one is needed */
 258                if (list_is_last(&espi->tx_t->transfer_list,
 259                    espi->m_transfers) || espi->rxskip) {
 260                        espi->tx_done = true;
 261                        return;
 262                }
 263                espi->tx_t = list_next_entry(espi->tx_t, transfer_list);
 264                espi->tx_pos = 0;
 265                /* continue with next transfer if tx fifo is not full */
 266                if (tx_fifo_avail)
 267                        goto start;
 268        }
 269}
 270
 271static void fsl_espi_read_rx_fifo(struct fsl_espi *espi, u32 events)
 272{
 273        u32 rx_fifo_avail = SPIE_RXCNT(events);
 274        unsigned int rx_left;
 275        void *rx_buf;
 276
 277start:
 278        rx_left = espi->rx_t->len - espi->rx_pos;
 279        rx_buf = espi->rx_t->rx_buf;
 280        while (rx_fifo_avail >= min(4U, rx_left) && rx_left) {
 281                if (rx_left >= 4) {
 282                        u32 val = fsl_espi_read_reg(espi, ESPI_SPIRF);
 283
 284                        if (rx_buf && espi->swab)
 285                                *(u32 *)(rx_buf + espi->rx_pos) = swahb32(val);
 286                        else if (rx_buf)
 287                                *(u32 *)(rx_buf + espi->rx_pos) = val;
 288                        espi->rx_pos += 4;
 289                        rx_left -= 4;
 290                        rx_fifo_avail -= 4;
 291                } else if (rx_left >= 2 && rx_buf && espi->swab) {
 292                        u16 val = fsl_espi_read_reg16(espi, ESPI_SPIRF);
 293
 294                        *(u16 *)(rx_buf + espi->rx_pos) = swab16(val);
 295                        espi->rx_pos += 2;
 296                        rx_left -= 2;
 297                        rx_fifo_avail -= 2;
 298                } else {
 299                        u8 val = fsl_espi_read_reg8(espi, ESPI_SPIRF);
 300
 301                        if (rx_buf)
 302                                *(u8 *)(rx_buf + espi->rx_pos) = val;
 303                        espi->rx_pos += 1;
 304                        rx_left -= 1;
 305                        rx_fifo_avail -= 1;
 306                }
 307        }
 308
 309        if (!rx_left) {
 310                if (list_is_last(&espi->rx_t->transfer_list,
 311                    espi->m_transfers)) {
 312                        espi->rx_done = true;
 313                        return;
 314                }
 315                espi->rx_t = list_next_entry(espi->rx_t, transfer_list);
 316                espi->rx_pos = 0;
 317                /* continue with next transfer if rx fifo is not empty */
 318                if (rx_fifo_avail)
 319                        goto start;
 320        }
 321}
 322
 323static void fsl_espi_setup_transfer(struct spi_device *spi,
 324                                        struct spi_transfer *t)
 325{
 326        struct fsl_espi *espi = spi_master_get_devdata(spi->master);
 327        int bits_per_word = t ? t->bits_per_word : spi->bits_per_word;
 328        u32 pm, hz = t ? t->speed_hz : spi->max_speed_hz;
 329        struct fsl_espi_cs *cs = spi_get_ctldata(spi);
 330        u32 hw_mode_old = cs->hw_mode;
 331
 332        /* mask out bits we are going to set */
 333        cs->hw_mode &= ~(CSMODE_LEN(0xF) | CSMODE_DIV16 | CSMODE_PM(0xF));
 334
 335        cs->hw_mode |= CSMODE_LEN(bits_per_word - 1);
 336
 337        pm = DIV_ROUND_UP(espi->spibrg, hz * 4) - 1;
 338
 339        if (pm > 15) {
 340                cs->hw_mode |= CSMODE_DIV16;
 341                pm = DIV_ROUND_UP(espi->spibrg, hz * 16 * 4) - 1;
 342        }
 343
 344        cs->hw_mode |= CSMODE_PM(pm);
 345
 346        /* don't write the mode register if the mode doesn't change */
 347        if (cs->hw_mode != hw_mode_old)
 348                fsl_espi_write_reg(espi, ESPI_SPMODEx(spi->chip_select),
 349                                   cs->hw_mode);
 350}
 351
 352static int fsl_espi_bufs(struct spi_device *spi, struct spi_transfer *t)
 353{
 354        struct fsl_espi *espi = spi_master_get_devdata(spi->master);
 355        unsigned int rx_len = t->len;
 356        u32 mask, spcom;
 357        int ret;
 358
 359        reinit_completion(&espi->done);
 360
 361        /* Set SPCOM[CS] and SPCOM[TRANLEN] field */
 362        spcom = SPCOM_CS(spi->chip_select);
 363        spcom |= SPCOM_TRANLEN(t->len - 1);
 364
 365        /* configure RXSKIP mode */
 366        if (espi->rxskip) {
 367                spcom |= SPCOM_RXSKIP(espi->rxskip);
 368                rx_len = t->len - espi->rxskip;
 369                if (t->rx_nbits == SPI_NBITS_DUAL)
 370                        spcom |= SPCOM_DO;
 371        }
 372
 373        fsl_espi_write_reg(espi, ESPI_SPCOM, spcom);
 374
 375        /* enable interrupts */
 376        mask = SPIM_DON;
 377        if (rx_len > FSL_ESPI_FIFO_SIZE)
 378                mask |= SPIM_RXT;
 379        fsl_espi_write_reg(espi, ESPI_SPIM, mask);
 380
 381        /* Prevent filling the fifo from getting interrupted */
 382        spin_lock_irq(&espi->lock);
 383        fsl_espi_fill_tx_fifo(espi, 0);
 384        spin_unlock_irq(&espi->lock);
 385
 386        /* Won't hang up forever, SPI bus sometimes got lost interrupts... */
 387        ret = wait_for_completion_timeout(&espi->done, 2 * HZ);
 388        if (ret == 0)
 389                dev_err(espi->dev, "Transfer timed out!\n");
 390
 391        /* disable rx ints */
 392        fsl_espi_write_reg(espi, ESPI_SPIM, 0);
 393
 394        return ret == 0 ? -ETIMEDOUT : 0;
 395}
 396
 397static int fsl_espi_trans(struct spi_message *m, struct spi_transfer *trans)
 398{
 399        struct fsl_espi *espi = spi_master_get_devdata(m->spi->master);
 400        struct spi_device *spi = m->spi;
 401        int ret;
 402
 403        /* In case of LSB-first and bits_per_word > 8 byte-swap all words */
 404        espi->swab = spi->mode & SPI_LSB_FIRST && trans->bits_per_word > 8;
 405
 406        espi->m_transfers = &m->transfers;
 407        espi->tx_t = list_first_entry(&m->transfers, struct spi_transfer,
 408                                      transfer_list);
 409        espi->tx_pos = 0;
 410        espi->tx_done = false;
 411        espi->rx_t = list_first_entry(&m->transfers, struct spi_transfer,
 412                                      transfer_list);
 413        espi->rx_pos = 0;
 414        espi->rx_done = false;
 415
 416        espi->rxskip = fsl_espi_check_rxskip_mode(m);
 417        if (trans->rx_nbits == SPI_NBITS_DUAL && !espi->rxskip) {
 418                dev_err(espi->dev, "Dual output mode requires RXSKIP mode!\n");
 419                return -EINVAL;
 420        }
 421
 422        /* In RXSKIP mode skip first transfer for reads */
 423        if (espi->rxskip)
 424                espi->rx_t = list_next_entry(espi->rx_t, transfer_list);
 425
 426        fsl_espi_setup_transfer(spi, trans);
 427
 428        ret = fsl_espi_bufs(spi, trans);
 429
 430        spi_transfer_delay_exec(trans);
 431
 432        return ret;
 433}
 434
 435static int fsl_espi_do_one_msg(struct spi_master *master,
 436                               struct spi_message *m)
 437{
 438        unsigned int rx_nbits = 0, delay_nsecs = 0;
 439        struct spi_transfer *t, trans = {};
 440        int ret;
 441
 442        ret = fsl_espi_check_message(m);
 443        if (ret)
 444                goto out;
 445
 446        list_for_each_entry(t, &m->transfers, transfer_list) {
 447                unsigned int delay = spi_delay_to_ns(&t->delay, t);
 448
 449                if (delay > delay_nsecs)
 450                        delay_nsecs = delay;
 451                if (t->rx_nbits > rx_nbits)
 452                        rx_nbits = t->rx_nbits;
 453        }
 454
 455        t = list_first_entry(&m->transfers, struct spi_transfer,
 456                             transfer_list);
 457
 458        trans.len = m->frame_length;
 459        trans.speed_hz = t->speed_hz;
 460        trans.bits_per_word = t->bits_per_word;
 461        trans.delay.value = delay_nsecs;
 462        trans.delay.unit = SPI_DELAY_UNIT_NSECS;
 463        trans.rx_nbits = rx_nbits;
 464
 465        if (trans.len)
 466                ret = fsl_espi_trans(m, &trans);
 467
 468        m->actual_length = ret ? 0 : trans.len;
 469out:
 470        if (m->status == -EINPROGRESS)
 471                m->status = ret;
 472
 473        spi_finalize_current_message(master);
 474
 475        return ret;
 476}
 477
 478static int fsl_espi_setup(struct spi_device *spi)
 479{
 480        struct fsl_espi *espi;
 481        u32 loop_mode;
 482        struct fsl_espi_cs *cs = spi_get_ctldata(spi);
 483
 484        if (!cs) {
 485                cs = kzalloc(sizeof(*cs), GFP_KERNEL);
 486                if (!cs)
 487                        return -ENOMEM;
 488                spi_set_ctldata(spi, cs);
 489        }
 490
 491        espi = spi_master_get_devdata(spi->master);
 492
 493        pm_runtime_get_sync(espi->dev);
 494
 495        cs->hw_mode = fsl_espi_read_reg(espi, ESPI_SPMODEx(spi->chip_select));
 496        /* mask out bits we are going to set */
 497        cs->hw_mode &= ~(CSMODE_CP_BEGIN_EDGECLK | CSMODE_CI_INACTIVEHIGH
 498                         | CSMODE_REV);
 499
 500        if (spi->mode & SPI_CPHA)
 501                cs->hw_mode |= CSMODE_CP_BEGIN_EDGECLK;
 502        if (spi->mode & SPI_CPOL)
 503                cs->hw_mode |= CSMODE_CI_INACTIVEHIGH;
 504        if (!(spi->mode & SPI_LSB_FIRST))
 505                cs->hw_mode |= CSMODE_REV;
 506
 507        /* Handle the loop mode */
 508        loop_mode = fsl_espi_read_reg(espi, ESPI_SPMODE);
 509        loop_mode &= ~SPMODE_LOOP;
 510        if (spi->mode & SPI_LOOP)
 511                loop_mode |= SPMODE_LOOP;
 512        fsl_espi_write_reg(espi, ESPI_SPMODE, loop_mode);
 513
 514        fsl_espi_setup_transfer(spi, NULL);
 515
 516        pm_runtime_mark_last_busy(espi->dev);
 517        pm_runtime_put_autosuspend(espi->dev);
 518
 519        return 0;
 520}
 521
 522static void fsl_espi_cleanup(struct spi_device *spi)
 523{
 524        struct fsl_espi_cs *cs = spi_get_ctldata(spi);
 525
 526        kfree(cs);
 527        spi_set_ctldata(spi, NULL);
 528}
 529
 530static void fsl_espi_cpu_irq(struct fsl_espi *espi, u32 events)
 531{
 532        if (!espi->rx_done)
 533                fsl_espi_read_rx_fifo(espi, events);
 534
 535        if (!espi->tx_done)
 536                fsl_espi_fill_tx_fifo(espi, events);
 537
 538        if (!espi->tx_done || !espi->rx_done)
 539                return;
 540
 541        /* we're done, but check for errors before returning */
 542        events = fsl_espi_read_reg(espi, ESPI_SPIE);
 543
 544        if (!(events & SPIE_DON))
 545                dev_err(espi->dev,
 546                        "Transfer done but SPIE_DON isn't set!\n");
 547
 548        if (SPIE_RXCNT(events) || SPIE_TXCNT(events) != FSL_ESPI_FIFO_SIZE) {
 549                dev_err(espi->dev, "Transfer done but rx/tx fifo's aren't empty!\n");
 550                dev_err(espi->dev, "SPIE_RXCNT = %d, SPIE_TXCNT = %d\n",
 551                        SPIE_RXCNT(events), SPIE_TXCNT(events));
 552        }
 553
 554        complete(&espi->done);
 555}
 556
 557static irqreturn_t fsl_espi_irq(s32 irq, void *context_data)
 558{
 559        struct fsl_espi *espi = context_data;
 560        u32 events, mask;
 561
 562        spin_lock(&espi->lock);
 563
 564        /* Get interrupt events(tx/rx) */
 565        events = fsl_espi_read_reg(espi, ESPI_SPIE);
 566        mask = fsl_espi_read_reg(espi, ESPI_SPIM);
 567        if (!(events & mask)) {
 568                spin_unlock(&espi->lock);
 569                return IRQ_NONE;
 570        }
 571
 572        dev_vdbg(espi->dev, "%s: events %x\n", __func__, events);
 573
 574        fsl_espi_cpu_irq(espi, events);
 575
 576        /* Clear the events */
 577        fsl_espi_write_reg(espi, ESPI_SPIE, events);
 578
 579        spin_unlock(&espi->lock);
 580
 581        return IRQ_HANDLED;
 582}
 583
 584#ifdef CONFIG_PM
 585static int fsl_espi_runtime_suspend(struct device *dev)
 586{
 587        struct spi_master *master = dev_get_drvdata(dev);
 588        struct fsl_espi *espi = spi_master_get_devdata(master);
 589        u32 regval;
 590
 591        regval = fsl_espi_read_reg(espi, ESPI_SPMODE);
 592        regval &= ~SPMODE_ENABLE;
 593        fsl_espi_write_reg(espi, ESPI_SPMODE, regval);
 594
 595        return 0;
 596}
 597
 598static int fsl_espi_runtime_resume(struct device *dev)
 599{
 600        struct spi_master *master = dev_get_drvdata(dev);
 601        struct fsl_espi *espi = spi_master_get_devdata(master);
 602        u32 regval;
 603
 604        regval = fsl_espi_read_reg(espi, ESPI_SPMODE);
 605        regval |= SPMODE_ENABLE;
 606        fsl_espi_write_reg(espi, ESPI_SPMODE, regval);
 607
 608        return 0;
 609}
 610#endif
 611
 612static size_t fsl_espi_max_message_size(struct spi_device *spi)
 613{
 614        return SPCOM_TRANLEN_MAX;
 615}
 616
 617static void fsl_espi_init_regs(struct device *dev, bool initial)
 618{
 619        struct spi_master *master = dev_get_drvdata(dev);
 620        struct fsl_espi *espi = spi_master_get_devdata(master);
 621        struct device_node *nc;
 622        u32 csmode, cs, prop;
 623        int ret;
 624
 625        /* SPI controller initializations */
 626        fsl_espi_write_reg(espi, ESPI_SPMODE, 0);
 627        fsl_espi_write_reg(espi, ESPI_SPIM, 0);
 628        fsl_espi_write_reg(espi, ESPI_SPCOM, 0);
 629        fsl_espi_write_reg(espi, ESPI_SPIE, 0xffffffff);
 630
 631        /* Init eSPI CS mode register */
 632        for_each_available_child_of_node(master->dev.of_node, nc) {
 633                /* get chip select */
 634                ret = of_property_read_u32(nc, "reg", &cs);
 635                if (ret || cs >= master->num_chipselect)
 636                        continue;
 637
 638                csmode = CSMODE_INIT_VAL;
 639
 640                /* check if CSBEF is set in device tree */
 641                ret = of_property_read_u32(nc, "fsl,csbef", &prop);
 642                if (!ret) {
 643                        csmode &= ~(CSMODE_BEF(0xf));
 644                        csmode |= CSMODE_BEF(prop);
 645                }
 646
 647                /* check if CSAFT is set in device tree */
 648                ret = of_property_read_u32(nc, "fsl,csaft", &prop);
 649                if (!ret) {
 650                        csmode &= ~(CSMODE_AFT(0xf));
 651                        csmode |= CSMODE_AFT(prop);
 652                }
 653
 654                fsl_espi_write_reg(espi, ESPI_SPMODEx(cs), csmode);
 655
 656                if (initial)
 657                        dev_info(dev, "cs=%u, init_csmode=0x%x\n", cs, csmode);
 658        }
 659
 660        /* Enable SPI interface */
 661        fsl_espi_write_reg(espi, ESPI_SPMODE, SPMODE_INIT_VAL | SPMODE_ENABLE);
 662}
 663
 664static int fsl_espi_probe(struct device *dev, struct resource *mem,
 665                          unsigned int irq, unsigned int num_cs)
 666{
 667        struct spi_master *master;
 668        struct fsl_espi *espi;
 669        int ret;
 670
 671        master = spi_alloc_master(dev, sizeof(struct fsl_espi));
 672        if (!master)
 673                return -ENOMEM;
 674
 675        dev_set_drvdata(dev, master);
 676
 677        master->mode_bits = SPI_RX_DUAL | SPI_CPOL | SPI_CPHA | SPI_CS_HIGH |
 678                            SPI_LSB_FIRST | SPI_LOOP;
 679        master->dev.of_node = dev->of_node;
 680        master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 16);
 681        master->setup = fsl_espi_setup;
 682        master->cleanup = fsl_espi_cleanup;
 683        master->transfer_one_message = fsl_espi_do_one_msg;
 684        master->auto_runtime_pm = true;
 685        master->max_message_size = fsl_espi_max_message_size;
 686        master->num_chipselect = num_cs;
 687
 688        espi = spi_master_get_devdata(master);
 689        spin_lock_init(&espi->lock);
 690
 691        espi->dev = dev;
 692        espi->spibrg = fsl_get_sys_freq();
 693        if (espi->spibrg == -1) {
 694                dev_err(dev, "Can't get sys frequency!\n");
 695                ret = -EINVAL;
 696                goto err_probe;
 697        }
 698        /* determined by clock divider fields DIV16/PM in register SPMODEx */
 699        master->min_speed_hz = DIV_ROUND_UP(espi->spibrg, 4 * 16 * 16);
 700        master->max_speed_hz = DIV_ROUND_UP(espi->spibrg, 4);
 701
 702        init_completion(&espi->done);
 703
 704        espi->reg_base = devm_ioremap_resource(dev, mem);
 705        if (IS_ERR(espi->reg_base)) {
 706                ret = PTR_ERR(espi->reg_base);
 707                goto err_probe;
 708        }
 709
 710        /* Register for SPI Interrupt */
 711        ret = devm_request_irq(dev, irq, fsl_espi_irq, 0, "fsl_espi", espi);
 712        if (ret)
 713                goto err_probe;
 714
 715        fsl_espi_init_regs(dev, true);
 716
 717        pm_runtime_set_autosuspend_delay(dev, AUTOSUSPEND_TIMEOUT);
 718        pm_runtime_use_autosuspend(dev);
 719        pm_runtime_set_active(dev);
 720        pm_runtime_enable(dev);
 721        pm_runtime_get_sync(dev);
 722
 723        ret = devm_spi_register_master(dev, master);
 724        if (ret < 0)
 725                goto err_pm;
 726
 727        dev_info(dev, "irq = %u\n", irq);
 728
 729        pm_runtime_mark_last_busy(dev);
 730        pm_runtime_put_autosuspend(dev);
 731
 732        return 0;
 733
 734err_pm:
 735        pm_runtime_put_noidle(dev);
 736        pm_runtime_disable(dev);
 737        pm_runtime_set_suspended(dev);
 738err_probe:
 739        spi_master_put(master);
 740        return ret;
 741}
 742
 743static int of_fsl_espi_get_chipselects(struct device *dev)
 744{
 745        struct device_node *np = dev->of_node;
 746        u32 num_cs;
 747        int ret;
 748
 749        ret = of_property_read_u32(np, "fsl,espi-num-chipselects", &num_cs);
 750        if (ret) {
 751                dev_err(dev, "No 'fsl,espi-num-chipselects' property\n");
 752                return 0;
 753        }
 754
 755        return num_cs;
 756}
 757
 758static int of_fsl_espi_probe(struct platform_device *ofdev)
 759{
 760        struct device *dev = &ofdev->dev;
 761        struct device_node *np = ofdev->dev.of_node;
 762        struct resource mem;
 763        unsigned int irq, num_cs;
 764        int ret;
 765
 766        if (of_property_read_bool(np, "mode")) {
 767                dev_err(dev, "mode property is not supported on ESPI!\n");
 768                return -EINVAL;
 769        }
 770
 771        num_cs = of_fsl_espi_get_chipselects(dev);
 772        if (!num_cs)
 773                return -EINVAL;
 774
 775        ret = of_address_to_resource(np, 0, &mem);
 776        if (ret)
 777                return ret;
 778
 779        irq = irq_of_parse_and_map(np, 0);
 780        if (!irq)
 781                return -EINVAL;
 782
 783        return fsl_espi_probe(dev, &mem, irq, num_cs);
 784}
 785
 786static int of_fsl_espi_remove(struct platform_device *dev)
 787{
 788        pm_runtime_disable(&dev->dev);
 789
 790        return 0;
 791}
 792
 793#ifdef CONFIG_PM_SLEEP
 794static int of_fsl_espi_suspend(struct device *dev)
 795{
 796        struct spi_master *master = dev_get_drvdata(dev);
 797        int ret;
 798
 799        ret = spi_master_suspend(master);
 800        if (ret)
 801                return ret;
 802
 803        return pm_runtime_force_suspend(dev);
 804}
 805
 806static int of_fsl_espi_resume(struct device *dev)
 807{
 808        struct spi_master *master = dev_get_drvdata(dev);
 809        int ret;
 810
 811        fsl_espi_init_regs(dev, false);
 812
 813        ret = pm_runtime_force_resume(dev);
 814        if (ret < 0)
 815                return ret;
 816
 817        return spi_master_resume(master);
 818}
 819#endif /* CONFIG_PM_SLEEP */
 820
 821static const struct dev_pm_ops espi_pm = {
 822        SET_RUNTIME_PM_OPS(fsl_espi_runtime_suspend,
 823                           fsl_espi_runtime_resume, NULL)
 824        SET_SYSTEM_SLEEP_PM_OPS(of_fsl_espi_suspend, of_fsl_espi_resume)
 825};
 826
 827static const struct of_device_id of_fsl_espi_match[] = {
 828        { .compatible = "fsl,mpc8536-espi" },
 829        {}
 830};
 831MODULE_DEVICE_TABLE(of, of_fsl_espi_match);
 832
 833static struct platform_driver fsl_espi_driver = {
 834        .driver = {
 835                .name = "fsl_espi",
 836                .of_match_table = of_fsl_espi_match,
 837                .pm = &espi_pm,
 838        },
 839        .probe          = of_fsl_espi_probe,
 840        .remove         = of_fsl_espi_remove,
 841};
 842module_platform_driver(fsl_espi_driver);
 843
 844MODULE_AUTHOR("Mingkai Hu");
 845MODULE_DESCRIPTION("Enhanced Freescale SPI Driver");
 846MODULE_LICENSE("GPL");
 847