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
  90 struct 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
 112 struct fsl_espi_cs {
 113         u32 hw_mode;
 114 };
 115
 116 static inline u32 fsl_espi_read_reg(struct fsl_espi *espi, int offset)
 117 {
 118         return ioread32be(espi->reg_base + offset);
 119 }
 120
 121 static inline u16 fsl_espi_read_reg16(struct fsl_espi *espi, int offset)
 122 {
 123         return ioread16be(espi->reg_base + offset);
 124 }
 125
 126 static inline u8 fsl_espi_read_reg8(struct fsl_espi *espi, int offset)
 127 {
 128         return ioread8(espi->reg_base + offset);
 129 }
 130
 131 static 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
 137 static 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
 143 static 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
 149 static 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
 183 static 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
 214 static 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;
 222 start:
 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
 271 static 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
 277 start:
 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
 323 static 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
 352 static 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
 397 static 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         if (trans->delay_usecs)
 431                 udelay(trans->delay_usecs);
 432
 433         return ret;
 434 }
 435
 436 static int fsl_espi_do_one_msg(struct spi_master *master,
 437                                struct spi_message *m)
 438 {
 439         unsigned int delay_usecs = 0, rx_nbits = 0;
 440         struct spi_transfer *t, trans = {};
 441         int ret;
 442
 443         ret = fsl_espi_check_message(m);
 444         if (ret)
 445                 goto out;
 446
 447         list_for_each_entry(t, &m->transfers, transfer_list) {
 448                 if (t->delay_usecs > delay_usecs)
 449                         delay_usecs = t->delay_usecs;
 450                 if (t->rx_nbits > rx_nbits)
 451                         rx_nbits = t->rx_nbits;
 452         }
 453
 454         t = list_first_entry(&m->transfers, struct spi_transfer,
 455                              transfer_list);
 456
 457         trans.len = m->frame_length;
 458         trans.speed_hz = t->speed_hz;
 459         trans.bits_per_word = t->bits_per_word;
 460         trans.delay_usecs = delay_usecs;
 461         trans.rx_nbits = rx_nbits;
 462
 463         if (trans.len)
 464                 ret = fsl_espi_trans(m, &trans);
 465
 466         m->actual_length = ret ? 0 : trans.len;
 467 out:
 468         if (m->status == -EINPROGRESS)
 469                 m->status = ret;
 470
 471         spi_finalize_current_message(master);
 472
 473         return ret;
 474 }
 475
 476 static int fsl_espi_setup(struct spi_device *spi)
 477 {
 478         struct fsl_espi *espi;
 479         u32 loop_mode;
 480         struct fsl_espi_cs *cs = spi_get_ctldata(spi);
 481
 482         if (!cs) {
 483                 cs = kzalloc(sizeof(*cs), GFP_KERNEL);
 484                 if (!cs)
 485                         return -ENOMEM;
 486                 spi_set_ctldata(spi, cs);
 487         }
 488
 489         espi = spi_master_get_devdata(spi->master);
 490
 491         pm_runtime_get_sync(espi->dev);
 492
 493         cs->hw_mode = fsl_espi_read_reg(espi, ESPI_SPMODEx(spi->chip_select));
 494         /* mask out bits we are going to set */
 495         cs->hw_mode &= ~(CSMODE_CP_BEGIN_EDGECLK | CSMODE_CI_INACTIVEHIGH
 496                          | CSMODE_REV);
 497
 498         if (spi->mode & SPI_CPHA)
 499                 cs->hw_mode |= CSMODE_CP_BEGIN_EDGECLK;
 500         if (spi->mode & SPI_CPOL)
 501                 cs->hw_mode |= CSMODE_CI_INACTIVEHIGH;
 502         if (!(spi->mode & SPI_LSB_FIRST))
 503                 cs->hw_mode |= CSMODE_REV;
 504
 505         /* Handle the loop mode */
 506         loop_mode = fsl_espi_read_reg(espi, ESPI_SPMODE);
 507         loop_mode &= ~SPMODE_LOOP;
 508         if (spi->mode & SPI_LOOP)
 509                 loop_mode |= SPMODE_LOOP;
 510         fsl_espi_write_reg(espi, ESPI_SPMODE, loop_mode);
 511
 512         fsl_espi_setup_transfer(spi, NULL);
 513
 514         pm_runtime_mark_last_busy(espi->dev);
 515         pm_runtime_put_autosuspend(espi->dev);
 516
 517         return 0;
 518 }
 519
 520 static void fsl_espi_cleanup(struct spi_device *spi)
 521 {
 522         struct fsl_espi_cs *cs = spi_get_ctldata(spi);
 523
 524         kfree(cs);
 525         spi_set_ctldata(spi, NULL);
 526 }
 527
 528 static void fsl_espi_cpu_irq(struct fsl_espi *espi, u32 events)
 529 {
 530         if (!espi->rx_done)
 531                 fsl_espi_read_rx_fifo(espi, events);
 532
 533         if (!espi->tx_done)
 534                 fsl_espi_fill_tx_fifo(espi, events);
 535
 536         if (!espi->tx_done || !espi->rx_done)
 537                 return;
 538
 539         /* we're done, but check for errors before returning */
 540         events = fsl_espi_read_reg(espi, ESPI_SPIE);
 541
 542         if (!(events & SPIE_DON))
 543                 dev_err(espi->dev,
 544                         "Transfer done but SPIE_DON isn't set!\n");
 545
 546         if (SPIE_RXCNT(events) || SPIE_TXCNT(events) != FSL_ESPI_FIFO_SIZE) {
 547                 dev_err(espi->dev, "Transfer done but rx/tx fifo's aren't empty!\n");
 548                 dev_err(espi->dev, "SPIE_RXCNT = %d, SPIE_TXCNT = %d\n",
 549                         SPIE_RXCNT(events), SPIE_TXCNT(events));
 550         }
 551
 552         complete(&espi->done);
 553 }
 554
 555 static irqreturn_t fsl_espi_irq(s32 irq, void *context_data)
 556 {
 557         struct fsl_espi *espi = context_data;
 558         u32 events;
 559
 560         spin_lock(&espi->lock);
 561
 562         /* Get interrupt events(tx/rx) */
 563         events = fsl_espi_read_reg(espi, ESPI_SPIE);
 564         if (!events) {
 565                 spin_unlock(&espi->lock);
 566                 return IRQ_NONE;
 567         }
 568
 569         dev_vdbg(espi->dev, "%s: events %x\n", __func__, events);
 570
 571         fsl_espi_cpu_irq(espi, events);
 572
 573         /* Clear the events */
 574         fsl_espi_write_reg(espi, ESPI_SPIE, events);
 575
 576         spin_unlock(&espi->lock);
 577
 578         return IRQ_HANDLED;
 579 }
 580
 581 #ifdef CONFIG_PM
 582 static int fsl_espi_runtime_suspend(struct device *dev)
 583 {
 584         struct spi_master *master = dev_get_drvdata(dev);
 585         struct fsl_espi *espi = spi_master_get_devdata(master);
 586         u32 regval;
 587
 588         regval = fsl_espi_read_reg(espi, ESPI_SPMODE);
 589         regval &= ~SPMODE_ENABLE;
 590         fsl_espi_write_reg(espi, ESPI_SPMODE, regval);
 591
 592         return 0;
 593 }
 594
 595 static int fsl_espi_runtime_resume(struct device *dev)
 596 {
 597         struct spi_master *master = dev_get_drvdata(dev);
 598         struct fsl_espi *espi = spi_master_get_devdata(master);
 599         u32 regval;
 600
 601         regval = fsl_espi_read_reg(espi, ESPI_SPMODE);
 602         regval |= SPMODE_ENABLE;
 603         fsl_espi_write_reg(espi, ESPI_SPMODE, regval);
 604
 605         return 0;
 606 }
 607 #endif
 608
 609 static size_t fsl_espi_max_message_size(struct spi_device *spi)
 610 {
 611         return SPCOM_TRANLEN_MAX;
 612 }
 613
 614 static void fsl_espi_init_regs(struct device *dev, bool initial)
 615 {
 616         struct spi_master *master = dev_get_drvdata(dev);
 617         struct fsl_espi *espi = spi_master_get_devdata(master);
 618         struct device_node *nc;
 619         u32 csmode, cs, prop;
 620         int ret;
 621
 622         /* SPI controller initializations */
 623         fsl_espi_write_reg(espi, ESPI_SPMODE, 0);
 624         fsl_espi_write_reg(espi, ESPI_SPIM, 0);
 625         fsl_espi_write_reg(espi, ESPI_SPCOM, 0);
 626         fsl_espi_write_reg(espi, ESPI_SPIE, 0xffffffff);
 627
 628         /* Init eSPI CS mode register */
 629         for_each_available_child_of_node(master->dev.of_node, nc) {
 630                 /* get chip select */
 631                 ret = of_property_read_u32(nc, "reg", &cs);
 632                 if (ret || cs >= master->num_chipselect)
 633                         continue;
 634
 635                 csmode = CSMODE_INIT_VAL;
 636
 637                 /* check if CSBEF is set in device tree */
 638                 ret = of_property_read_u32(nc, "fsl,csbef", &prop);
 639                 if (!ret) {
 640                         csmode &= ~(CSMODE_BEF(0xf));
 641                         csmode |= CSMODE_BEF(prop);
 642                 }
 643
 644                 /* check if CSAFT is set in device tree */
 645                 ret = of_property_read_u32(nc, "fsl,csaft", &prop);
 646                 if (!ret) {
 647                         csmode &= ~(CSMODE_AFT(0xf));
 648                         csmode |= CSMODE_AFT(prop);
 649                 }
 650
 651                 fsl_espi_write_reg(espi, ESPI_SPMODEx(cs), csmode);
 652
 653                 if (initial)
 654                         dev_info(dev, "cs=%u, init_csmode=0x%x\n", cs, csmode);
 655         }
 656
 657         /* Enable SPI interface */
 658         fsl_espi_write_reg(espi, ESPI_SPMODE, SPMODE_INIT_VAL | SPMODE_ENABLE);
 659 }
 660
 661 static int fsl_espi_probe(struct device *dev, struct resource *mem,
 662                           unsigned int irq, unsigned int num_cs)
 663 {
 664         struct spi_master *master;
 665         struct fsl_espi *espi;
 666         int ret;
 667
 668         master = spi_alloc_master(dev, sizeof(struct fsl_espi));
 669         if (!master)
 670                 return -ENOMEM;
 671
 672         dev_set_drvdata(dev, master);
 673
 674         master->mode_bits = SPI_RX_DUAL | SPI_CPOL | SPI_CPHA | SPI_CS_HIGH |
 675                             SPI_LSB_FIRST | SPI_LOOP;
 676         master->dev.of_node = dev->of_node;
 677         master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 16);
 678         master->setup = fsl_espi_setup;
 679         master->cleanup = fsl_espi_cleanup;
 680         master->transfer_one_message = fsl_espi_do_one_msg;
 681         master->auto_runtime_pm = true;
 682         master->max_message_size = fsl_espi_max_message_size;
 683         master->num_chipselect = num_cs;
 684
 685         espi = spi_master_get_devdata(master);
 686         spin_lock_init(&espi->lock);
 687
 688         espi->dev = dev;
 689         espi->spibrg = fsl_get_sys_freq();
 690         if (espi->spibrg == -1) {
 691                 dev_err(dev, "Can't get sys frequency!\n");
 692                 ret = -EINVAL;
 693                 goto err_probe;
 694         }
 695         /* determined by clock divider fields DIV16/PM in register SPMODEx */
 696         master->min_speed_hz = DIV_ROUND_UP(espi->spibrg, 4 * 16 * 16);
 697         master->max_speed_hz = DIV_ROUND_UP(espi->spibrg, 4);
 698
 699         init_completion(&espi->done);
 700
 701         espi->reg_base = devm_ioremap_resource(dev, mem);
 702         if (IS_ERR(espi->reg_base)) {
 703                 ret = PTR_ERR(espi->reg_base);
 704                 goto err_probe;
 705         }
 706
 707         /* Register for SPI Interrupt */
 708         ret = devm_request_irq(dev, irq, fsl_espi_irq, 0, "fsl_espi", espi);
 709         if (ret)
 710                 goto err_probe;
 711
 712         fsl_espi_init_regs(dev, true);
 713
 714         pm_runtime_set_autosuspend_delay(dev, AUTOSUSPEND_TIMEOUT);
 715         pm_runtime_use_autosuspend(dev);
 716         pm_runtime_set_active(dev);
 717         pm_runtime_enable(dev);
 718         pm_runtime_get_sync(dev);
 719
 720         ret = devm_spi_register_master(dev, master);
 721         if (ret < 0)
 722                 goto err_pm;
 723
 724         dev_info(dev, "at 0x%p (irq = %u)\n", espi->reg_base, irq);
 725
 726         pm_runtime_mark_last_busy(dev);
 727         pm_runtime_put_autosuspend(dev);
 728
 729         return 0;
 730
 731 err_pm:
 732         pm_runtime_put_noidle(dev);
 733         pm_runtime_disable(dev);
 734         pm_runtime_set_suspended(dev);
 735 err_probe:
 736         spi_master_put(master);
 737         return ret;
 738 }
 739
 740 static int of_fsl_espi_get_chipselects(struct device *dev)
 741 {
 742         struct device_node *np = dev->of_node;
 743         u32 num_cs;
 744         int ret;
 745
 746         ret = of_property_read_u32(np, "fsl,espi-num-chipselects", &num_cs);
 747         if (ret) {
 748                 dev_err(dev, "No 'fsl,espi-num-chipselects' property\n");
 749                 return 0;
 750         }
 751
 752         return num_cs;
 753 }
 754
 755 static int of_fsl_espi_probe(struct platform_device *ofdev)
 756 {
 757         struct device *dev = &ofdev->dev;
 758         struct device_node *np = ofdev->dev.of_node;
 759         struct resource mem;
 760         unsigned int irq, num_cs;
 761         int ret;
 762
 763         if (of_property_read_bool(np, "mode")) {
 764                 dev_err(dev, "mode property is not supported on ESPI!\n");
 765                 return -EINVAL;
 766         }
 767
 768         num_cs = of_fsl_espi_get_chipselects(dev);
 769         if (!num_cs)
 770                 return -EINVAL;
 771
 772         ret = of_address_to_resource(np, 0, &mem);
 773         if (ret)
 774                 return ret;
 775
 776         irq = irq_of_parse_and_map(np, 0);
 777         if (!irq)
 778                 return -EINVAL;
 779
 780         return fsl_espi_probe(dev, &mem, irq, num_cs);
 781 }
 782
 783 static int of_fsl_espi_remove(struct platform_device *dev)
 784 {
 785         pm_runtime_disable(&dev->dev);
 786
 787         return 0;
 788 }
 789
 790 #ifdef CONFIG_PM_SLEEP
 791 static int of_fsl_espi_suspend(struct device *dev)
 792 {
 793         struct spi_master *master = dev_get_drvdata(dev);
 794         int ret;
 795
 796         ret = spi_master_suspend(master);
 797         if (ret)
 798                 return ret;
 799
 800         return pm_runtime_force_suspend(dev);
 801 }
 802
 803 static int of_fsl_espi_resume(struct device *dev)
 804 {
 805         struct spi_master *master = dev_get_drvdata(dev);
 806         int ret;
 807
 808         fsl_espi_init_regs(dev, false);
 809
 810         ret = pm_runtime_force_resume(dev);
 811         if (ret < 0)
 812                 return ret;
 813
 814         return spi_master_resume(master);
 815 }
 816 #endif /* CONFIG_PM_SLEEP */
 817
 818 static const struct dev_pm_ops espi_pm = {
 819         SET_RUNTIME_PM_OPS(fsl_espi_runtime_suspend,
 820                            fsl_espi_runtime_resume, NULL)
 821         SET_SYSTEM_SLEEP_PM_OPS(of_fsl_espi_suspend, of_fsl_espi_resume)
 822 };
 823
 824 static const struct of_device_id of_fsl_espi_match[] = {
 825         { .compatible = "fsl,mpc8536-espi" },
 826         {}
 827 };
 828 MODULE_DEVICE_TABLE(of, of_fsl_espi_match);
 829
 830 static struct platform_driver fsl_espi_driver = {
 831         .driver = {
 832                 .name = "fsl_espi",
 833                 .of_match_table = of_fsl_espi_match,
 834                 .pm = &espi_pm,
 835         },
 836         .probe          = of_fsl_espi_probe,
 837         .remove         = of_fsl_espi_remove,
 838 };
 839 module_platform_driver(fsl_espi_driver);
 840
 841 MODULE_AUTHOR("Mingkai Hu");
 842 MODULE_DESCRIPTION("Enhanced Freescale SPI Driver");
 843 MODULE_LICENSE("GPL");