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         spi_transfer_delay_exec(trans);
 431
 432         return ret;
 433 }
 434
 435 static int fsl_espi_do_one_msg(struct spi_master *master,
 436                                struct spi_message *m)
 437 {
 438         unsigned int delay_usecs = 0, rx_nbits = 0;
 439         unsigned int delay_nsecs = 0, delay_nsecs1 = 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) {
 449                         if (t->delay_usecs > delay_usecs) {
 450                                 delay_usecs = t->delay_usecs;
 451                                 delay_nsecs = delay_usecs * 1000;
 452                         }
 453                 } else {
 454                         delay_nsecs1 = spi_delay_to_ns(&t->delay, t);
 455                         if (delay_nsecs1 > delay_nsecs)
 456                                 delay_nsecs = delay_nsecs1;
 457                 }
 458                 if (t->rx_nbits > rx_nbits)
 459                         rx_nbits = t->rx_nbits;
 460         }
 461
 462         t = list_first_entry(&m->transfers, struct spi_transfer,
 463                              transfer_list);
 464
 465         trans.len = m->frame_length;
 466         trans.speed_hz = t->speed_hz;
 467         trans.bits_per_word = t->bits_per_word;
 468         trans.delay.value = delay_nsecs;
 469         trans.delay.unit = SPI_DELAY_UNIT_NSECS;
 470         trans.rx_nbits = rx_nbits;
 471
 472         if (trans.len)
 473                 ret = fsl_espi_trans(m, &trans);
 474
 475         m->actual_length = ret ? 0 : trans.len;
 476 out:
 477         if (m->status == -EINPROGRESS)
 478                 m->status = ret;
 479
 480         spi_finalize_current_message(master);
 481
 482         return ret;
 483 }
 484
 485 static int fsl_espi_setup(struct spi_device *spi)
 486 {
 487         struct fsl_espi *espi;
 488         u32 loop_mode;
 489         struct fsl_espi_cs *cs = spi_get_ctldata(spi);
 490
 491         if (!cs) {
 492                 cs = kzalloc(sizeof(*cs), GFP_KERNEL);
 493                 if (!cs)
 494                         return -ENOMEM;
 495                 spi_set_ctldata(spi, cs);
 496         }
 497
 498         espi = spi_master_get_devdata(spi->master);
 499
 500         pm_runtime_get_sync(espi->dev);
 501
 502         cs->hw_mode = fsl_espi_read_reg(espi, ESPI_SPMODEx(spi->chip_select));
 503         /* mask out bits we are going to set */
 504         cs->hw_mode &= ~(CSMODE_CP_BEGIN_EDGECLK | CSMODE_CI_INACTIVEHIGH
 505                          | CSMODE_REV);
 506
 507         if (spi->mode & SPI_CPHA)
 508                 cs->hw_mode |= CSMODE_CP_BEGIN_EDGECLK;
 509         if (spi->mode & SPI_CPOL)
 510                 cs->hw_mode |= CSMODE_CI_INACTIVEHIGH;
 511         if (!(spi->mode & SPI_LSB_FIRST))
 512                 cs->hw_mode |= CSMODE_REV;
 513
 514         /* Handle the loop mode */
 515         loop_mode = fsl_espi_read_reg(espi, ESPI_SPMODE);
 516         loop_mode &= ~SPMODE_LOOP;
 517         if (spi->mode & SPI_LOOP)
 518                 loop_mode |= SPMODE_LOOP;
 519         fsl_espi_write_reg(espi, ESPI_SPMODE, loop_mode);
 520
 521         fsl_espi_setup_transfer(spi, NULL);
 522
 523         pm_runtime_mark_last_busy(espi->dev);
 524         pm_runtime_put_autosuspend(espi->dev);
 525
 526         return 0;
 527 }
 528
 529 static void fsl_espi_cleanup(struct spi_device *spi)
 530 {
 531         struct fsl_espi_cs *cs = spi_get_ctldata(spi);
 532
 533         kfree(cs);
 534         spi_set_ctldata(spi, NULL);
 535 }
 536
 537 static void fsl_espi_cpu_irq(struct fsl_espi *espi, u32 events)
 538 {
 539         if (!espi->rx_done)
 540                 fsl_espi_read_rx_fifo(espi, events);
 541
 542         if (!espi->tx_done)
 543                 fsl_espi_fill_tx_fifo(espi, events);
 544
 545         if (!espi->tx_done || !espi->rx_done)
 546                 return;
 547
 548         /* we're done, but check for errors before returning */
 549         events = fsl_espi_read_reg(espi, ESPI_SPIE);
 550
 551         if (!(events & SPIE_DON))
 552                 dev_err(espi->dev,
 553                         "Transfer done but SPIE_DON isn't set!\n");
 554
 555         if (SPIE_RXCNT(events) || SPIE_TXCNT(events) != FSL_ESPI_FIFO_SIZE) {
 556                 dev_err(espi->dev, "Transfer done but rx/tx fifo's aren't empty!\n");
 557                 dev_err(espi->dev, "SPIE_RXCNT = %d, SPIE_TXCNT = %d\n",
 558                         SPIE_RXCNT(events), SPIE_TXCNT(events));
 559         }
 560
 561         complete(&espi->done);
 562 }
 563
 564 static irqreturn_t fsl_espi_irq(s32 irq, void *context_data)
 565 {
 566         struct fsl_espi *espi = context_data;
 567         u32 events;
 568
 569         spin_lock(&espi->lock);
 570
 571         /* Get interrupt events(tx/rx) */
 572         events = fsl_espi_read_reg(espi, ESPI_SPIE);
 573         if (!events) {
 574                 spin_unlock(&espi->lock);
 575                 return IRQ_NONE;
 576         }
 577
 578         dev_vdbg(espi->dev, "%s: events %x\n", __func__, events);
 579
 580         fsl_espi_cpu_irq(espi, events);
 581
 582         /* Clear the events */
 583         fsl_espi_write_reg(espi, ESPI_SPIE, events);
 584
 585         spin_unlock(&espi->lock);
 586
 587         return IRQ_HANDLED;
 588 }
 589
 590 #ifdef CONFIG_PM
 591 static int fsl_espi_runtime_suspend(struct device *dev)
 592 {
 593         struct spi_master *master = dev_get_drvdata(dev);
 594         struct fsl_espi *espi = spi_master_get_devdata(master);
 595         u32 regval;
 596
 597         regval = fsl_espi_read_reg(espi, ESPI_SPMODE);
 598         regval &= ~SPMODE_ENABLE;
 599         fsl_espi_write_reg(espi, ESPI_SPMODE, regval);
 600
 601         return 0;
 602 }
 603
 604 static int fsl_espi_runtime_resume(struct device *dev)
 605 {
 606         struct spi_master *master = dev_get_drvdata(dev);
 607         struct fsl_espi *espi = spi_master_get_devdata(master);
 608         u32 regval;
 609
 610         regval = fsl_espi_read_reg(espi, ESPI_SPMODE);
 611         regval |= SPMODE_ENABLE;
 612         fsl_espi_write_reg(espi, ESPI_SPMODE, regval);
 613
 614         return 0;
 615 }
 616 #endif
 617
 618 static size_t fsl_espi_max_message_size(struct spi_device *spi)
 619 {
 620         return SPCOM_TRANLEN_MAX;
 621 }
 622
 623 static void fsl_espi_init_regs(struct device *dev, bool initial)
 624 {
 625         struct spi_master *master = dev_get_drvdata(dev);
 626         struct fsl_espi *espi = spi_master_get_devdata(master);
 627         struct device_node *nc;
 628         u32 csmode, cs, prop;
 629         int ret;
 630
 631         /* SPI controller initializations */
 632         fsl_espi_write_reg(espi, ESPI_SPMODE, 0);
 633         fsl_espi_write_reg(espi, ESPI_SPIM, 0);
 634         fsl_espi_write_reg(espi, ESPI_SPCOM, 0);
 635         fsl_espi_write_reg(espi, ESPI_SPIE, 0xffffffff);
 636
 637         /* Init eSPI CS mode register */
 638         for_each_available_child_of_node(master->dev.of_node, nc) {
 639                 /* get chip select */
 640                 ret = of_property_read_u32(nc, "reg", &cs);
 641                 if (ret || cs >= master->num_chipselect)
 642                         continue;
 643
 644                 csmode = CSMODE_INIT_VAL;
 645
 646                 /* check if CSBEF is set in device tree */
 647                 ret = of_property_read_u32(nc, "fsl,csbef", &prop);
 648                 if (!ret) {
 649                         csmode &= ~(CSMODE_BEF(0xf));
 650                         csmode |= CSMODE_BEF(prop);
 651                 }
 652
 653                 /* check if CSAFT is set in device tree */
 654                 ret = of_property_read_u32(nc, "fsl,csaft", &prop);
 655                 if (!ret) {
 656                         csmode &= ~(CSMODE_AFT(0xf));
 657                         csmode |= CSMODE_AFT(prop);
 658                 }
 659
 660                 fsl_espi_write_reg(espi, ESPI_SPMODEx(cs), csmode);
 661
 662                 if (initial)
 663                         dev_info(dev, "cs=%u, init_csmode=0x%x\n", cs, csmode);
 664         }
 665
 666         /* Enable SPI interface */
 667         fsl_espi_write_reg(espi, ESPI_SPMODE, SPMODE_INIT_VAL | SPMODE_ENABLE);
 668 }
 669
 670 static int fsl_espi_probe(struct device *dev, struct resource *mem,
 671                           unsigned int irq, unsigned int num_cs)
 672 {
 673         struct spi_master *master;
 674         struct fsl_espi *espi;
 675         int ret;
 676
 677         master = spi_alloc_master(dev, sizeof(struct fsl_espi));
 678         if (!master)
 679                 return -ENOMEM;
 680
 681         dev_set_drvdata(dev, master);
 682
 683         master->mode_bits = SPI_RX_DUAL | SPI_CPOL | SPI_CPHA | SPI_CS_HIGH |
 684                             SPI_LSB_FIRST | SPI_LOOP;
 685         master->dev.of_node = dev->of_node;
 686         master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 16);
 687         master->setup = fsl_espi_setup;
 688         master->cleanup = fsl_espi_cleanup;
 689         master->transfer_one_message = fsl_espi_do_one_msg;
 690         master->auto_runtime_pm = true;
 691         master->max_message_size = fsl_espi_max_message_size;
 692         master->num_chipselect = num_cs;
 693
 694         espi = spi_master_get_devdata(master);
 695         spin_lock_init(&espi->lock);
 696
 697         espi->dev = dev;
 698         espi->spibrg = fsl_get_sys_freq();
 699         if (espi->spibrg == -1) {
 700                 dev_err(dev, "Can't get sys frequency!\n");
 701                 ret = -EINVAL;
 702                 goto err_probe;
 703         }
 704         /* determined by clock divider fields DIV16/PM in register SPMODEx */
 705         master->min_speed_hz = DIV_ROUND_UP(espi->spibrg, 4 * 16 * 16);
 706         master->max_speed_hz = DIV_ROUND_UP(espi->spibrg, 4);
 707
 708         init_completion(&espi->done);
 709
 710         espi->reg_base = devm_ioremap_resource(dev, mem);
 711         if (IS_ERR(espi->reg_base)) {
 712                 ret = PTR_ERR(espi->reg_base);
 713                 goto err_probe;
 714         }
 715
 716         /* Register for SPI Interrupt */
 717         ret = devm_request_irq(dev, irq, fsl_espi_irq, 0, "fsl_espi", espi);
 718         if (ret)
 719                 goto err_probe;
 720
 721         fsl_espi_init_regs(dev, true);
 722
 723         pm_runtime_set_autosuspend_delay(dev, AUTOSUSPEND_TIMEOUT);
 724         pm_runtime_use_autosuspend(dev);
 725         pm_runtime_set_active(dev);
 726         pm_runtime_enable(dev);
 727         pm_runtime_get_sync(dev);
 728
 729         ret = devm_spi_register_master(dev, master);
 730         if (ret < 0)
 731                 goto err_pm;
 732
 733         dev_info(dev, "at 0x%p (irq = %u)\n", espi->reg_base, irq);
 734
 735         pm_runtime_mark_last_busy(dev);
 736         pm_runtime_put_autosuspend(dev);
 737
 738         return 0;
 739
 740 err_pm:
 741         pm_runtime_put_noidle(dev);
 742         pm_runtime_disable(dev);
 743         pm_runtime_set_suspended(dev);
 744 err_probe:
 745         spi_master_put(master);
 746         return ret;
 747 }
 748
 749 static int of_fsl_espi_get_chipselects(struct device *dev)
 750 {
 751         struct device_node *np = dev->of_node;
 752         u32 num_cs;
 753         int ret;
 754
 755         ret = of_property_read_u32(np, "fsl,espi-num-chipselects", &num_cs);
 756         if (ret) {
 757                 dev_err(dev, "No 'fsl,espi-num-chipselects' property\n");
 758                 return 0;
 759         }
 760
 761         return num_cs;
 762 }
 763
 764 static int of_fsl_espi_probe(struct platform_device *ofdev)
 765 {
 766         struct device *dev = &ofdev->dev;
 767         struct device_node *np = ofdev->dev.of_node;
 768         struct resource mem;
 769         unsigned int irq, num_cs;
 770         int ret;
 771
 772         if (of_property_read_bool(np, "mode")) {
 773                 dev_err(dev, "mode property is not supported on ESPI!\n");
 774                 return -EINVAL;
 775         }
 776
 777         num_cs = of_fsl_espi_get_chipselects(dev);
 778         if (!num_cs)
 779                 return -EINVAL;
 780
 781         ret = of_address_to_resource(np, 0, &mem);
 782         if (ret)
 783                 return ret;
 784
 785         irq = irq_of_parse_and_map(np, 0);
 786         if (!irq)
 787                 return -EINVAL;
 788
 789         return fsl_espi_probe(dev, &mem, irq, num_cs);
 790 }
 791
 792 static int of_fsl_espi_remove(struct platform_device *dev)
 793 {
 794         pm_runtime_disable(&dev->dev);
 795
 796         return 0;
 797 }
 798
 799 #ifdef CONFIG_PM_SLEEP
 800 static int of_fsl_espi_suspend(struct device *dev)
 801 {
 802         struct spi_master *master = dev_get_drvdata(dev);
 803         int ret;
 804
 805         ret = spi_master_suspend(master);
 806         if (ret)
 807                 return ret;
 808
 809         return pm_runtime_force_suspend(dev);
 810 }
 811
 812 static int of_fsl_espi_resume(struct device *dev)
 813 {
 814         struct spi_master *master = dev_get_drvdata(dev);
 815         int ret;
 816
 817         fsl_espi_init_regs(dev, false);
 818
 819         ret = pm_runtime_force_resume(dev);
 820         if (ret < 0)
 821                 return ret;
 822
 823         return spi_master_resume(master);
 824 }
 825 #endif /* CONFIG_PM_SLEEP */
 826
 827 static const struct dev_pm_ops espi_pm = {
 828         SET_RUNTIME_PM_OPS(fsl_espi_runtime_suspend,
 829                            fsl_espi_runtime_resume, NULL)
 830         SET_SYSTEM_SLEEP_PM_OPS(of_fsl_espi_suspend, of_fsl_espi_resume)
 831 };
 832
 833 static const struct of_device_id of_fsl_espi_match[] = {
 834         { .compatible = "fsl,mpc8536-espi" },
 835         {}
 836 };
 837 MODULE_DEVICE_TABLE(of, of_fsl_espi_match);
 838
 839 static struct platform_driver fsl_espi_driver = {
 840         .driver = {
 841                 .name = "fsl_espi",
 842                 .of_match_table = of_fsl_espi_match,
 843                 .pm = &espi_pm,
 844         },
 845         .probe          = of_fsl_espi_probe,
 846         .remove         = of_fsl_espi_remove,
 847 };
 848 module_platform_driver(fsl_espi_driver);
 849
 850 MODULE_AUTHOR("Mingkai Hu");
 851 MODULE_DESCRIPTION("Enhanced Freescale SPI Driver");
 852 MODULE_LICENSE("GPL");