drivers/staging/greybus/spilib.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Greybus SPI library
   4  *
   5  * Copyright 2014-2016 Google Inc.
   6  * Copyright 2014-2016 Linaro Ltd.
   7  */
   8
   9 #include <linux/bitops.h>
  10 #include <linux/kernel.h>
  11 #include <linux/module.h>
  12 #include <linux/slab.h>
  13 #include <linux/greybus.h>
  14 #include <linux/spi/spi.h>
  15
  16 #include "spilib.h"
  17
  18 struct gb_spilib {
  19         struct gb_connection    *connection;
  20         struct device           *parent;
  21         struct spi_transfer     *first_xfer;
  22         struct spi_transfer     *last_xfer;
  23         struct spilib_ops       *ops;
  24         u32                     rx_xfer_offset;
  25         u32                     tx_xfer_offset;
  26         u32                     last_xfer_size;
  27         unsigned int            op_timeout;
  28         u16                     mode;
  29         u16                     flags;
  30         u32                     bits_per_word_mask;
  31         u8                      num_chipselect;
  32         u32                     min_speed_hz;
  33         u32                     max_speed_hz;
  34 };
  35
  36 #define GB_SPI_STATE_MSG_DONE           ((void *)0)
  37 #define GB_SPI_STATE_MSG_IDLE           ((void *)1)
  38 #define GB_SPI_STATE_MSG_RUNNING        ((void *)2)
  39 #define GB_SPI_STATE_OP_READY           ((void *)3)
  40 #define GB_SPI_STATE_OP_DONE            ((void *)4)
  41 #define GB_SPI_STATE_MSG_ERROR          ((void *)-1)
  42
  43 #define XFER_TIMEOUT_TOLERANCE          200
  44
  45 static struct spi_master *get_master_from_spi(struct gb_spilib *spi)
  46 {
  47         return gb_connection_get_data(spi->connection);
  48 }
  49
  50 static int tx_header_fit_operation(u32 tx_size, u32 count, size_t data_max)
  51 {
  52         size_t headers_size;
  53
  54         data_max -= sizeof(struct gb_spi_transfer_request);
  55         headers_size = (count + 1) * sizeof(struct gb_spi_transfer);
  56
  57         return tx_size + headers_size > data_max ? 0 : 1;
  58 }
  59
  60 static size_t calc_rx_xfer_size(u32 rx_size, u32 *tx_xfer_size, u32 len,
  61                                 size_t data_max)
  62 {
  63         size_t rx_xfer_size;
  64
  65         data_max -= sizeof(struct gb_spi_transfer_response);
  66
  67         if (rx_size + len > data_max)
  68                 rx_xfer_size = data_max - rx_size;
  69         else
  70                 rx_xfer_size = len;
  71
  72         /* if this is a write_read, for symmetry read the same as write */
  73         if (*tx_xfer_size && rx_xfer_size > *tx_xfer_size)
  74                 rx_xfer_size = *tx_xfer_size;
  75         if (*tx_xfer_size && rx_xfer_size < *tx_xfer_size)
  76                 *tx_xfer_size = rx_xfer_size;
  77
  78         return rx_xfer_size;
  79 }
  80
  81 static size_t calc_tx_xfer_size(u32 tx_size, u32 count, size_t len,
  82                                 size_t data_max)
  83 {
  84         size_t headers_size;
  85
  86         data_max -= sizeof(struct gb_spi_transfer_request);
  87         headers_size = (count + 1) * sizeof(struct gb_spi_transfer);
  88
  89         if (tx_size + headers_size + len > data_max)
  90                 return data_max - (tx_size + sizeof(struct gb_spi_transfer));
  91
  92         return len;
  93 }
  94
  95 static void clean_xfer_state(struct gb_spilib *spi)
  96 {
  97         spi->first_xfer = NULL;
  98         spi->last_xfer = NULL;
  99         spi->rx_xfer_offset = 0;
 100         spi->tx_xfer_offset = 0;
 101         spi->last_xfer_size = 0;
 102         spi->op_timeout = 0;
 103 }
 104
 105 static bool is_last_xfer_done(struct gb_spilib *spi)
 106 {
 107         struct spi_transfer *last_xfer = spi->last_xfer;
 108
 109         if ((spi->tx_xfer_offset + spi->last_xfer_size == last_xfer->len) ||
 110             (spi->rx_xfer_offset + spi->last_xfer_size == last_xfer->len))
 111                 return true;
 112
 113         return false;
 114 }
 115
 116 static int setup_next_xfer(struct gb_spilib *spi, struct spi_message *msg)
 117 {
 118         struct spi_transfer *last_xfer = spi->last_xfer;
 119
 120         if (msg->state != GB_SPI_STATE_OP_DONE)
 121                 return 0;
 122
 123         /*
 124          * if we transferred all content of the last transfer, reset values and
 125          * check if this was the last transfer in the message
 126          */
 127         if (is_last_xfer_done(spi)) {
 128                 spi->tx_xfer_offset = 0;
 129                 spi->rx_xfer_offset = 0;
 130                 spi->op_timeout = 0;
 131                 if (last_xfer == list_last_entry(&msg->transfers,
 132                                                  struct spi_transfer,
 133                                                  transfer_list))
 134                         msg->state = GB_SPI_STATE_MSG_DONE;
 135                 else
 136                         spi->first_xfer = list_next_entry(last_xfer,
 137                                                           transfer_list);
 138                 return 0;
 139         }
 140
 141         spi->first_xfer = last_xfer;
 142         if (last_xfer->tx_buf)
 143                 spi->tx_xfer_offset += spi->last_xfer_size;
 144
 145         if (last_xfer->rx_buf)
 146                 spi->rx_xfer_offset += spi->last_xfer_size;
 147
 148         return 0;
 149 }
 150
 151 static struct spi_transfer *get_next_xfer(struct spi_transfer *xfer,
 152                                           struct spi_message *msg)
 153 {
 154         if (xfer == list_last_entry(&msg->transfers, struct spi_transfer,
 155                                     transfer_list))
 156                 return NULL;
 157
 158         return list_next_entry(xfer, transfer_list);
 159 }
 160
 161 /* Routines to transfer data */
 162 static struct gb_operation *gb_spi_operation_create(struct gb_spilib *spi,
 163                 struct gb_connection *connection, struct spi_message *msg)
 164 {
 165         struct gb_spi_transfer_request *request;
 166         struct spi_device *dev = msg->spi;
 167         struct spi_transfer *xfer;
 168         struct gb_spi_transfer *gb_xfer;
 169         struct gb_operation *operation;
 170         u32 tx_size = 0, rx_size = 0, count = 0, xfer_len = 0, request_size;
 171         u32 tx_xfer_size = 0, rx_xfer_size = 0, len;
 172         u32 total_len = 0;
 173         unsigned int xfer_timeout;
 174         size_t data_max;
 175         void *tx_data;
 176
 177         data_max = gb_operation_get_payload_size_max(connection);
 178         xfer = spi->first_xfer;
 179
 180         /* Find number of transfers queued and tx/rx length in the message */
 181
 182         while (msg->state != GB_SPI_STATE_OP_READY) {
 183                 msg->state = GB_SPI_STATE_MSG_RUNNING;
 184                 spi->last_xfer = xfer;
 185
 186                 if (!xfer->tx_buf && !xfer->rx_buf) {
 187                         dev_err(spi->parent,
 188                                 "bufferless transfer, length %u\n", xfer->len);
 189                         msg->state = GB_SPI_STATE_MSG_ERROR;
 190                         return NULL;
 191                 }
 192
 193                 tx_xfer_size = 0;
 194                 rx_xfer_size = 0;
 195
 196                 if (xfer->tx_buf) {
 197                         len = xfer->len - spi->tx_xfer_offset;
 198                         if (!tx_header_fit_operation(tx_size, count, data_max))
 199                                 break;
 200                         tx_xfer_size = calc_tx_xfer_size(tx_size, count,
 201                                                          len, data_max);
 202                         spi->last_xfer_size = tx_xfer_size;
 203                 }
 204
 205                 if (xfer->rx_buf) {
 206                         len = xfer->len - spi->rx_xfer_offset;
 207                         rx_xfer_size = calc_rx_xfer_size(rx_size, &tx_xfer_size,
 208                                                          len, data_max);
 209                         spi->last_xfer_size = rx_xfer_size;
 210                 }
 211
 212                 tx_size += tx_xfer_size;
 213                 rx_size += rx_xfer_size;
 214
 215                 total_len += spi->last_xfer_size;
 216                 count++;
 217
 218                 xfer = get_next_xfer(xfer, msg);
 219                 if (!xfer || total_len >= data_max)
 220                         msg->state = GB_SPI_STATE_OP_READY;
 221         }
 222
 223         /*
 224          * In addition to space for all message descriptors we need
 225          * to have enough to hold all tx data.
 226          */
 227         request_size = sizeof(*request);
 228         request_size += count * sizeof(*gb_xfer);
 229         request_size += tx_size;
 230
 231         /* Response consists only of incoming data */
 232         operation = gb_operation_create(connection, GB_SPI_TYPE_TRANSFER,
 233                                         request_size, rx_size, GFP_KERNEL);
 234         if (!operation)
 235                 return NULL;
 236
 237         request = operation->request->payload;
 238         request->count = cpu_to_le16(count);
 239         request->mode = dev->mode;
 240         request->chip_select = dev->chip_select;
 241
 242         gb_xfer = &request->transfers[0];
 243         tx_data = gb_xfer + count;      /* place tx data after last gb_xfer */
 244
 245         /* Fill in the transfers array */
 246         xfer = spi->first_xfer;
 247         while (msg->state != GB_SPI_STATE_OP_DONE) {
 248                 int xfer_delay;
 249                 if (xfer == spi->last_xfer)
 250                         xfer_len = spi->last_xfer_size;
 251                 else
 252                         xfer_len = xfer->len;
 253
 254                 /* make sure we do not timeout in a slow transfer */
 255                 xfer_timeout = xfer_len * 8 * MSEC_PER_SEC / xfer->speed_hz;
 256                 xfer_timeout += GB_OPERATION_TIMEOUT_DEFAULT;
 257
 258                 if (xfer_timeout > spi->op_timeout)
 259                         spi->op_timeout = xfer_timeout;
 260
 261                 gb_xfer->speed_hz = cpu_to_le32(xfer->speed_hz);
 262                 gb_xfer->len = cpu_to_le32(xfer_len);
 263                 xfer_delay = spi_delay_to_ns(&xfer->delay, xfer) / 1000;
 264                 xfer_delay = clamp_t(u16, xfer_delay, 0, U16_MAX);
 265                 gb_xfer->delay_usecs = cpu_to_le16(xfer_delay);
 266                 gb_xfer->cs_change = xfer->cs_change;
 267                 gb_xfer->bits_per_word = xfer->bits_per_word;
 268
 269                 /* Copy tx data */
 270                 if (xfer->tx_buf) {
 271                         gb_xfer->xfer_flags |= GB_SPI_XFER_WRITE;
 272                         memcpy(tx_data, xfer->tx_buf + spi->tx_xfer_offset,
 273                                xfer_len);
 274                         tx_data += xfer_len;
 275                 }
 276
 277                 if (xfer->rx_buf)
 278                         gb_xfer->xfer_flags |= GB_SPI_XFER_READ;
 279
 280                 if (xfer == spi->last_xfer) {
 281                         if (!is_last_xfer_done(spi))
 282                                 gb_xfer->xfer_flags |= GB_SPI_XFER_INPROGRESS;
 283                         msg->state = GB_SPI_STATE_OP_DONE;
 284                         continue;
 285                 }
 286
 287                 gb_xfer++;
 288                 xfer = get_next_xfer(xfer, msg);
 289         }
 290
 291         msg->actual_length += total_len;
 292
 293         return operation;
 294 }
 295
 296 static void gb_spi_decode_response(struct gb_spilib *spi,
 297                                    struct spi_message *msg,
 298                                    struct gb_spi_transfer_response *response)
 299 {
 300         struct spi_transfer *xfer = spi->first_xfer;
 301         void *rx_data = response->data;
 302         u32 xfer_len;
 303
 304         while (xfer) {
 305                 /* Copy rx data */
 306                 if (xfer->rx_buf) {
 307                         if (xfer == spi->first_xfer)
 308                                 xfer_len = xfer->len - spi->rx_xfer_offset;
 309                         else if (xfer == spi->last_xfer)
 310                                 xfer_len = spi->last_xfer_size;
 311                         else
 312                                 xfer_len = xfer->len;
 313
 314                         memcpy(xfer->rx_buf + spi->rx_xfer_offset, rx_data,
 315                                xfer_len);
 316                         rx_data += xfer_len;
 317                 }
 318
 319                 if (xfer == spi->last_xfer)
 320                         break;
 321
 322                 xfer = list_next_entry(xfer, transfer_list);
 323         }
 324 }
 325
 326 static int gb_spi_transfer_one_message(struct spi_master *master,
 327                                        struct spi_message *msg)
 328 {
 329         struct gb_spilib *spi = spi_master_get_devdata(master);
 330         struct gb_connection *connection = spi->connection;
 331         struct gb_spi_transfer_response *response;
 332         struct gb_operation *operation;
 333         int ret = 0;
 334
 335         spi->first_xfer = list_first_entry_or_null(&msg->transfers,
 336                                                    struct spi_transfer,
 337                                                    transfer_list);
 338         if (!spi->first_xfer) {
 339                 ret = -ENOMEM;
 340                 goto out;
 341         }
 342
 343         msg->state = GB_SPI_STATE_MSG_IDLE;
 344
 345         while (msg->state != GB_SPI_STATE_MSG_DONE &&
 346                msg->state != GB_SPI_STATE_MSG_ERROR) {
 347                 operation = gb_spi_operation_create(spi, connection, msg);
 348                 if (!operation) {
 349                         msg->state = GB_SPI_STATE_MSG_ERROR;
 350                         ret = -EINVAL;
 351                         continue;
 352                 }
 353
 354                 ret = gb_operation_request_send_sync_timeout(operation,
 355                                                              spi->op_timeout);
 356                 if (!ret) {
 357                         response = operation->response->payload;
 358                         if (response)
 359                                 gb_spi_decode_response(spi, msg, response);
 360                 } else {
 361                         dev_err(spi->parent,
 362                                 "transfer operation failed: %d\n", ret);
 363                         msg->state = GB_SPI_STATE_MSG_ERROR;
 364                 }
 365
 366                 gb_operation_put(operation);
 367                 setup_next_xfer(spi, msg);
 368         }
 369
 370 out:
 371         msg->status = ret;
 372         clean_xfer_state(spi);
 373         spi_finalize_current_message(master);
 374
 375         return ret;
 376 }
 377
 378 static int gb_spi_prepare_transfer_hardware(struct spi_master *master)
 379 {
 380         struct gb_spilib *spi = spi_master_get_devdata(master);
 381
 382         return spi->ops->prepare_transfer_hardware(spi->parent);
 383 }
 384
 385 static int gb_spi_unprepare_transfer_hardware(struct spi_master *master)
 386 {
 387         struct gb_spilib *spi = spi_master_get_devdata(master);
 388
 389         spi->ops->unprepare_transfer_hardware(spi->parent);
 390
 391         return 0;
 392 }
 393
 394 static int gb_spi_setup(struct spi_device *spi)
 395 {
 396         /* Nothing to do for now */
 397         return 0;
 398 }
 399
 400 static void gb_spi_cleanup(struct spi_device *spi)
 401 {
 402         /* Nothing to do for now */
 403 }
 404
 405 /* Routines to get controller information */
 406
 407 /*
 408  * Map Greybus spi mode bits/flags/bpw into Linux ones.
 409  * All bits are same for now and so these macro's return same values.
 410  */
 411 #define gb_spi_mode_map(mode) mode
 412 #define gb_spi_flags_map(flags) flags
 413
 414 static int gb_spi_get_master_config(struct gb_spilib *spi)
 415 {
 416         struct gb_spi_master_config_response response;
 417         u16 mode, flags;
 418         int ret;
 419
 420         ret = gb_operation_sync(spi->connection, GB_SPI_TYPE_MASTER_CONFIG,
 421                                 NULL, 0, &response, sizeof(response));
 422         if (ret < 0)
 423                 return ret;
 424
 425         mode = le16_to_cpu(response.mode);
 426         spi->mode = gb_spi_mode_map(mode);
 427
 428         flags = le16_to_cpu(response.flags);
 429         spi->flags = gb_spi_flags_map(flags);
 430
 431         spi->bits_per_word_mask = le32_to_cpu(response.bits_per_word_mask);
 432         spi->num_chipselect = response.num_chipselect;
 433
 434         spi->min_speed_hz = le32_to_cpu(response.min_speed_hz);
 435         spi->max_speed_hz = le32_to_cpu(response.max_speed_hz);
 436
 437         return 0;
 438 }
 439
 440 static int gb_spi_setup_device(struct gb_spilib *spi, u8 cs)
 441 {
 442         struct spi_master *master = get_master_from_spi(spi);
 443         struct gb_spi_device_config_request request;
 444         struct gb_spi_device_config_response response;
 445         struct spi_board_info spi_board = { {0} };
 446         struct spi_device *spidev;
 447         int ret;
 448         u8 dev_type;
 449
 450         request.chip_select = cs;
 451
 452         ret = gb_operation_sync(spi->connection, GB_SPI_TYPE_DEVICE_CONFIG,
 453                                 &request, sizeof(request),
 454                                 &response, sizeof(response));
 455         if (ret < 0)
 456                 return ret;
 457
 458         dev_type = response.device_type;
 459
 460         if (dev_type == GB_SPI_SPI_DEV)
 461                 strscpy(spi_board.modalias, "spidev",
 462                         sizeof(spi_board.modalias));
 463         else if (dev_type == GB_SPI_SPI_NOR)
 464                 strscpy(spi_board.modalias, "spi-nor",
 465                         sizeof(spi_board.modalias));
 466         else if (dev_type == GB_SPI_SPI_MODALIAS)
 467                 memcpy(spi_board.modalias, response.name,
 468                        sizeof(spi_board.modalias));
 469         else
 470                 return -EINVAL;
 471
 472         spi_board.mode          = le16_to_cpu(response.mode);
 473         spi_board.bus_num       = master->bus_num;
 474         spi_board.chip_select   = cs;
 475         spi_board.max_speed_hz  = le32_to_cpu(response.max_speed_hz);
 476
 477         spidev = spi_new_device(master, &spi_board);
 478         if (!spidev)
 479                 return -EINVAL;
 480
 481         return 0;
 482 }
 483
 484 int gb_spilib_master_init(struct gb_connection *connection, struct device *dev,
 485                           struct spilib_ops *ops)
 486 {
 487         struct gb_spilib *spi;
 488         struct spi_master *master;
 489         int ret;
 490         u8 i;
 491
 492         /* Allocate master with space for data */
 493         master = spi_alloc_master(dev, sizeof(*spi));
 494         if (!master) {
 495                 dev_err(dev, "cannot alloc SPI master\n");
 496                 return -ENOMEM;
 497         }
 498
 499         spi = spi_master_get_devdata(master);
 500         spi->connection = connection;
 501         gb_connection_set_data(connection, master);
 502         spi->parent = dev;
 503         spi->ops = ops;
 504
 505         /* get master configuration */
 506         ret = gb_spi_get_master_config(spi);
 507         if (ret)
 508                 goto exit_spi_put;
 509
 510         master->bus_num = -1; /* Allow spi-core to allocate it dynamically */
 511         master->num_chipselect = spi->num_chipselect;
 512         master->mode_bits = spi->mode;
 513         master->flags = spi->flags;
 514         master->bits_per_word_mask = spi->bits_per_word_mask;
 515
 516         /* Attach methods */
 517         master->cleanup = gb_spi_cleanup;
 518         master->setup = gb_spi_setup;
 519         master->transfer_one_message = gb_spi_transfer_one_message;
 520
 521         if (ops && ops->prepare_transfer_hardware) {
 522                 master->prepare_transfer_hardware =
 523                         gb_spi_prepare_transfer_hardware;
 524         }
 525
 526         if (ops && ops->unprepare_transfer_hardware) {
 527                 master->unprepare_transfer_hardware =
 528                         gb_spi_unprepare_transfer_hardware;
 529         }
 530
 531         master->auto_runtime_pm = true;
 532
 533         ret = spi_register_master(master);
 534         if (ret < 0)
 535                 goto exit_spi_put;
 536
 537         /* now, fetch the devices configuration */
 538         for (i = 0; i < spi->num_chipselect; i++) {
 539                 ret = gb_spi_setup_device(spi, i);
 540                 if (ret < 0) {
 541                         dev_err(dev, "failed to allocate spi device %d: %d\n",
 542                                 i, ret);
 543                         goto exit_spi_unregister;
 544                 }
 545         }
 546
 547         return 0;
 548
 549 exit_spi_put:
 550         spi_master_put(master);
 551
 552         return ret;
 553
 554 exit_spi_unregister:
 555         spi_unregister_master(master);
 556
 557         return ret;
 558 }
 559 EXPORT_SYMBOL_GPL(gb_spilib_master_init);
 560
 561 void gb_spilib_master_exit(struct gb_connection *connection)
 562 {
 563         struct spi_master *master = gb_connection_get_data(connection);
 564
 565         spi_unregister_master(master);
 566 }
 567 EXPORT_SYMBOL_GPL(gb_spilib_master_exit);
 568
 569 MODULE_LICENSE("GPL v2");