drivers/staging/greybus/spilib.c

   1 /*
   2  * Greybus SPI library
   3  *
   4  * Copyright 2014-2016 Google Inc.
   5  * Copyright 2014-2016 Linaro Ltd.
   6  *
   7  * Released under the GPLv2 only.
   8  */
   9
  10 #include <linux/bitops.h>
  11 #include <linux/kernel.h>
  12 #include <linux/module.h>
  13 #include <linux/slab.h>
  14 #include <linux/spi/spi.h>
  15
  16 #include "greybus.h"
  17 #include "spilib.h"
  18
  19 struct gb_spilib {
  20         struct gb_connection    *connection;
  21         struct device           *parent;
  22         struct spi_transfer     *first_xfer;
  23         struct spi_transfer     *last_xfer;
  24         struct spilib_ops       *ops;
  25         u32                     rx_xfer_offset;
  26         u32                     tx_xfer_offset;
  27         u32                     last_xfer_size;
  28         unsigned int            op_timeout;
  29         u16                     mode;
  30         u16                     flags;
  31         u32                     bits_per_word_mask;
  32         u8                      num_chipselect;
  33         u32                     min_speed_hz;
  34         u32                     max_speed_hz;
  35 };
  36
  37 #define GB_SPI_STATE_MSG_DONE           ((void *)0)
  38 #define GB_SPI_STATE_MSG_IDLE           ((void *)1)
  39 #define GB_SPI_STATE_MSG_RUNNING        ((void *)2)
  40 #define GB_SPI_STATE_OP_READY           ((void *)3)
  41 #define GB_SPI_STATE_OP_DONE            ((void *)4)
  42 #define GB_SPI_STATE_MSG_ERROR          ((void *)-1)
  43
  44 #define XFER_TIMEOUT_TOLERANCE          200
  45
  46 static struct spi_master *get_master_from_spi(struct gb_spilib *spi)
  47 {
  48         return gb_connection_get_data(spi->connection);
  49 }
  50
  51 static int tx_header_fit_operation(u32 tx_size, u32 count, size_t data_max)
  52 {
  53         size_t headers_size;
  54
  55         data_max -= sizeof(struct gb_spi_transfer_request);
  56         headers_size = (count + 1) * sizeof(struct gb_spi_transfer);
  57
  58         return tx_size + headers_size > data_max ? 0 : 1;
  59 }
  60
  61 static size_t calc_rx_xfer_size(u32 rx_size, u32 *tx_xfer_size, u32 len,
  62                                 size_t data_max)
  63 {
  64         size_t rx_xfer_size;
  65
  66         data_max -= sizeof(struct gb_spi_transfer_response);
  67
  68         if (rx_size + len > data_max)
  69                 rx_xfer_size = data_max - rx_size;
  70         else
  71                 rx_xfer_size = len;
  72
  73         /* if this is a write_read, for symmetry read the same as write */
  74         if (*tx_xfer_size && rx_xfer_size > *tx_xfer_size)
  75                 rx_xfer_size = *tx_xfer_size;
  76         if (*tx_xfer_size && rx_xfer_size < *tx_xfer_size)
  77                 *tx_xfer_size = rx_xfer_size;
  78
  79         return rx_xfer_size;
  80 }
  81
  82 static size_t calc_tx_xfer_size(u32 tx_size, u32 count, size_t len,
  83                                 size_t data_max)
  84 {
  85         size_t headers_size;
  86
  87         data_max -= sizeof(struct gb_spi_transfer_request);
  88         headers_size = (count + 1) * sizeof(struct gb_spi_transfer);
  89
  90         if (tx_size + headers_size + len > data_max)
  91                 return data_max - (tx_size + sizeof(struct gb_spi_transfer));
  92
  93         return len;
  94 }
  95
  96 static void clean_xfer_state(struct gb_spilib *spi)
  97 {
  98         spi->first_xfer = NULL;
  99         spi->last_xfer = NULL;
 100         spi->rx_xfer_offset = 0;
 101         spi->tx_xfer_offset = 0;
 102         spi->last_xfer_size = 0;
 103         spi->op_timeout = 0;
 104 }
 105
 106 static bool is_last_xfer_done(struct gb_spilib *spi)
 107 {
 108         struct spi_transfer *last_xfer = spi->last_xfer;
 109
 110         if ((spi->tx_xfer_offset + spi->last_xfer_size == last_xfer->len) ||
 111             (spi->rx_xfer_offset + spi->last_xfer_size == last_xfer->len))
 112                 return true;
 113
 114         return false;
 115 }
 116
 117 static int setup_next_xfer(struct gb_spilib *spi, struct spi_message *msg)
 118 {
 119         struct spi_transfer *last_xfer = spi->last_xfer;
 120
 121         if (msg->state != GB_SPI_STATE_OP_DONE)
 122                 return 0;
 123
 124         /*
 125          * if we transferred all content of the last transfer, reset values and
 126          * check if this was the last transfer in the message
 127          */
 128         if (is_last_xfer_done(spi)) {
 129                 spi->tx_xfer_offset = 0;
 130                 spi->rx_xfer_offset = 0;
 131                 spi->op_timeout = 0;
 132                 if (last_xfer == list_last_entry(&msg->transfers,
 133                                                  struct spi_transfer,
 134                                                  transfer_list))
 135                         msg->state = GB_SPI_STATE_MSG_DONE;
 136                 else
 137                         spi->first_xfer = list_next_entry(last_xfer,
 138                                                           transfer_list);
 139                 return 0;
 140         }
 141
 142         spi->first_xfer = last_xfer;
 143         if (last_xfer->tx_buf)
 144                 spi->tx_xfer_offset += spi->last_xfer_size;
 145
 146         if (last_xfer->rx_buf)
 147                 spi->rx_xfer_offset += spi->last_xfer_size;
 148
 149         return 0;
 150 }
 151
 152 static struct spi_transfer *get_next_xfer(struct spi_transfer *xfer,
 153                                           struct spi_message *msg)
 154 {
 155         if (xfer == list_last_entry(&msg->transfers, struct spi_transfer,
 156                                     transfer_list))
 157                 return NULL;
 158
 159         return list_next_entry(xfer, transfer_list);
 160 }
 161
 162 /* Routines to transfer data */
 163 static struct gb_operation *gb_spi_operation_create(struct gb_spilib *spi,
 164                 struct gb_connection *connection, struct spi_message *msg)
 165 {
 166         struct gb_spi_transfer_request *request;
 167         struct spi_device *dev = msg->spi;
 168         struct spi_transfer *xfer;
 169         struct gb_spi_transfer *gb_xfer;
 170         struct gb_operation *operation;
 171         u32 tx_size = 0, rx_size = 0, count = 0, xfer_len = 0, request_size;
 172         u32 tx_xfer_size = 0, rx_xfer_size = 0, len;
 173         u32 total_len = 0;
 174         unsigned int xfer_timeout;
 175         size_t data_max;
 176         void *tx_data;
 177
 178         data_max = gb_operation_get_payload_size_max(connection);
 179         xfer = spi->first_xfer;
 180
 181         /* Find number of transfers queued and tx/rx length in the message */
 182
 183         while (msg->state != GB_SPI_STATE_OP_READY) {
 184                 msg->state = GB_SPI_STATE_MSG_RUNNING;
 185                 spi->last_xfer = xfer;
 186
 187                 if (!xfer->tx_buf && !xfer->rx_buf) {
 188                         dev_err(spi->parent,
 189                                 "bufferless transfer, length %u\n", xfer->len);
 190                         msg->state = GB_SPI_STATE_MSG_ERROR;
 191                         return NULL;
 192                 }
 193
 194                 tx_xfer_size = 0;
 195                 rx_xfer_size = 0;
 196
 197                 if (xfer->tx_buf) {
 198                         len = xfer->len - spi->tx_xfer_offset;
 199                         if (!tx_header_fit_operation(tx_size, count, data_max))
 200                                 break;
 201                         tx_xfer_size = calc_tx_xfer_size(tx_size, count,
 202                                                          len, data_max);
 203                         spi->last_xfer_size = tx_xfer_size;
 204                 }
 205
 206                 if (xfer->rx_buf) {
 207                         len = xfer->len - spi->rx_xfer_offset;
 208                         rx_xfer_size = calc_rx_xfer_size(rx_size, &tx_xfer_size,
 209                                                          len, data_max);
 210                         spi->last_xfer_size = rx_xfer_size;
 211                 }
 212
 213                 tx_size += tx_xfer_size;
 214                 rx_size += rx_xfer_size;
 215
 216                 total_len += spi->last_xfer_size;
 217                 count++;
 218
 219                 xfer = get_next_xfer(xfer, msg);
 220                 if (!xfer || total_len >= data_max)
 221                         msg->state = GB_SPI_STATE_OP_READY;
 222         }
 223
 224         /*
 225          * In addition to space for all message descriptors we need
 226          * to have enough to hold all tx data.
 227          */
 228         request_size = sizeof(*request);
 229         request_size += count * sizeof(*gb_xfer);
 230         request_size += tx_size;
 231
 232         /* Response consists only of incoming data */
 233         operation = gb_operation_create(connection, GB_SPI_TYPE_TRANSFER,
 234                                         request_size, rx_size, GFP_KERNEL);
 235         if (!operation)
 236                 return NULL;
 237
 238         request = operation->request->payload;
 239         request->count = cpu_to_le16(count);
 240         request->mode = dev->mode;
 241         request->chip_select = dev->chip_select;
 242
 243         gb_xfer = &request->transfers[0];
 244         tx_data = gb_xfer + count;      /* place tx data after last gb_xfer */
 245
 246         /* Fill in the transfers array */
 247         xfer = spi->first_xfer;
 248         while (msg->state != GB_SPI_STATE_OP_DONE) {
 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                 gb_xfer->delay_usecs = cpu_to_le16(xfer->delay_usecs);
 264                 gb_xfer->cs_change = xfer->cs_change;
 265                 gb_xfer->bits_per_word = xfer->bits_per_word;
 266
 267                 /* Copy tx data */
 268                 if (xfer->tx_buf) {
 269                         gb_xfer->xfer_flags |= GB_SPI_XFER_WRITE;
 270                         memcpy(tx_data, xfer->tx_buf + spi->tx_xfer_offset,
 271                                xfer_len);
 272                         tx_data += xfer_len;
 273                 }
 274
 275                 if (xfer->rx_buf)
 276                         gb_xfer->xfer_flags |= GB_SPI_XFER_READ;
 277
 278                 if (xfer == spi->last_xfer) {
 279                         if (!is_last_xfer_done(spi))
 280                                 gb_xfer->xfer_flags |= GB_SPI_XFER_INPROGRESS;
 281                         msg->state = GB_SPI_STATE_OP_DONE;
 282                         continue;
 283                 }
 284
 285                 gb_xfer++;
 286                 xfer = get_next_xfer(xfer, msg);
 287         }
 288
 289         msg->actual_length += total_len;
 290
 291         return operation;
 292 }
 293
 294 static void gb_spi_decode_response(struct gb_spilib *spi,
 295                                    struct spi_message *msg,
 296                                    struct gb_spi_transfer_response *response)
 297 {
 298         struct spi_transfer *xfer = spi->first_xfer;
 299         void *rx_data = response->data;
 300         u32 xfer_len;
 301
 302         while (xfer) {
 303                 /* Copy rx data */
 304                 if (xfer->rx_buf) {
 305                         if (xfer == spi->first_xfer)
 306                                 xfer_len = xfer->len - spi->rx_xfer_offset;
 307                         else if (xfer == spi->last_xfer)
 308                                 xfer_len = spi->last_xfer_size;
 309                         else
 310                                 xfer_len = xfer->len;
 311
 312                         memcpy(xfer->rx_buf + spi->rx_xfer_offset, rx_data,
 313                                xfer_len);
 314                         rx_data += xfer_len;
 315                 }
 316
 317                 if (xfer == spi->last_xfer)
 318                         break;
 319
 320                 xfer = list_next_entry(xfer, transfer_list);
 321         }
 322 }
 323
 324 static int gb_spi_transfer_one_message(struct spi_master *master,
 325                                        struct spi_message *msg)
 326 {
 327         struct gb_spilib *spi = spi_master_get_devdata(master);
 328         struct gb_connection *connection = spi->connection;
 329         struct gb_spi_transfer_response *response;
 330         struct gb_operation *operation;
 331         int ret = 0;
 332
 333         spi->first_xfer = list_first_entry_or_null(&msg->transfers,
 334                                                    struct spi_transfer,
 335                                                    transfer_list);
 336         if (!spi->first_xfer) {
 337                 ret = -ENOMEM;
 338                 goto out;
 339         }
 340
 341         msg->state = GB_SPI_STATE_MSG_IDLE;
 342
 343         while (msg->state != GB_SPI_STATE_MSG_DONE &&
 344                msg->state != GB_SPI_STATE_MSG_ERROR) {
 345                 operation = gb_spi_operation_create(spi, connection, msg);
 346                 if (!operation) {
 347                         msg->state = GB_SPI_STATE_MSG_ERROR;
 348                         ret = -EINVAL;
 349                         continue;
 350                 }
 351
 352                 ret = gb_operation_request_send_sync_timeout(operation,
 353                                                              spi->op_timeout);
 354                 if (!ret) {
 355                         response = operation->response->payload;
 356                         if (response)
 357                                 gb_spi_decode_response(spi, msg, response);
 358                 } else {
 359                         dev_err(spi->parent,
 360                                 "transfer operation failed: %d\n", ret);
 361                         msg->state = GB_SPI_STATE_MSG_ERROR;
 362                 }
 363
 364                 gb_operation_put(operation);
 365                 setup_next_xfer(spi, msg);
 366         }
 367
 368 out:
 369         msg->status = ret;
 370         clean_xfer_state(spi);
 371         spi_finalize_current_message(master);
 372
 373         return ret;
 374 }
 375
 376 static int gb_spi_prepare_transfer_hardware(struct spi_master *master)
 377 {
 378         struct gb_spilib *spi = spi_master_get_devdata(master);
 379
 380         return spi->ops->prepare_transfer_hardware(spi->parent);
 381 }
 382
 383 static int gb_spi_unprepare_transfer_hardware(struct spi_master *master)
 384 {
 385         struct gb_spilib *spi = spi_master_get_devdata(master);
 386
 387         spi->ops->unprepare_transfer_hardware(spi->parent);
 388
 389         return 0;
 390 }
 391
 392 static int gb_spi_setup(struct spi_device *spi)
 393 {
 394         /* Nothing to do for now */
 395         return 0;
 396 }
 397
 398 static void gb_spi_cleanup(struct spi_device *spi)
 399 {
 400         /* Nothing to do for now */
 401 }
 402
 403 /* Routines to get controller information */
 404
 405 /*
 406  * Map Greybus spi mode bits/flags/bpw into Linux ones.
 407  * All bits are same for now and so these macro's return same values.
 408  */
 409 #define gb_spi_mode_map(mode) mode
 410 #define gb_spi_flags_map(flags) flags
 411
 412 static int gb_spi_get_master_config(struct gb_spilib *spi)
 413 {
 414         struct gb_spi_master_config_response response;
 415         u16 mode, flags;
 416         int ret;
 417
 418         ret = gb_operation_sync(spi->connection, GB_SPI_TYPE_MASTER_CONFIG,
 419                                 NULL, 0, &response, sizeof(response));
 420         if (ret < 0)
 421                 return ret;
 422
 423         mode = le16_to_cpu(response.mode);
 424         spi->mode = gb_spi_mode_map(mode);
 425
 426         flags = le16_to_cpu(response.flags);
 427         spi->flags = gb_spi_flags_map(flags);
 428
 429         spi->bits_per_word_mask = le32_to_cpu(response.bits_per_word_mask);
 430         spi->num_chipselect = response.num_chipselect;
 431
 432         spi->min_speed_hz = le32_to_cpu(response.min_speed_hz);
 433         spi->max_speed_hz = le32_to_cpu(response.max_speed_hz);
 434
 435         return 0;
 436 }
 437
 438 static int gb_spi_setup_device(struct gb_spilib *spi, u8 cs)
 439 {
 440         struct spi_master *master = get_master_from_spi(spi);
 441         struct gb_spi_device_config_request request;
 442         struct gb_spi_device_config_response response;
 443         struct spi_board_info spi_board = { {0} };
 444         struct spi_device *spidev;
 445         int ret;
 446         u8 dev_type;
 447
 448         request.chip_select = cs;
 449
 450         ret = gb_operation_sync(spi->connection, GB_SPI_TYPE_DEVICE_CONFIG,
 451                                 &request, sizeof(request),
 452                                 &response, sizeof(response));
 453         if (ret < 0)
 454                 return ret;
 455
 456         dev_type = response.device_type;
 457
 458         if (dev_type == GB_SPI_SPI_DEV)
 459                 strlcpy(spi_board.modalias, "spidev",
 460                         sizeof(spi_board.modalias));
 461         else if (dev_type == GB_SPI_SPI_NOR)
 462                 strlcpy(spi_board.modalias, "spi-nor",
 463                         sizeof(spi_board.modalias));
 464         else if (dev_type == GB_SPI_SPI_MODALIAS)
 465                 memcpy(spi_board.modalias, response.name,
 466                        sizeof(spi_board.modalias));
 467         else
 468                 return -EINVAL;
 469
 470         spi_board.mode          = le16_to_cpu(response.mode);
 471         spi_board.bus_num       = master->bus_num;
 472         spi_board.chip_select   = cs;
 473         spi_board.max_speed_hz  = le32_to_cpu(response.max_speed_hz);
 474
 475         spidev = spi_new_device(master, &spi_board);
 476         if (!spidev)
 477                 return -EINVAL;
 478
 479         return 0;
 480 }
 481
 482 int gb_spilib_master_init(struct gb_connection *connection, struct device *dev,
 483                           struct spilib_ops *ops)
 484 {
 485         struct gb_spilib *spi;
 486         struct spi_master *master;
 487         int ret;
 488         u8 i;
 489
 490         /* Allocate master with space for data */
 491         master = spi_alloc_master(dev, sizeof(*spi));
 492         if (!master) {
 493                 dev_err(dev, "cannot alloc SPI master\n");
 494                 return -ENOMEM;
 495         }
 496
 497         spi = spi_master_get_devdata(master);
 498         spi->connection = connection;
 499         gb_connection_set_data(connection, master);
 500         spi->parent = dev;
 501         spi->ops = ops;
 502
 503         /* get master configuration */
 504         ret = gb_spi_get_master_config(spi);
 505         if (ret)
 506                 goto exit_spi_put;
 507
 508         master->bus_num = -1; /* Allow spi-core to allocate it dynamically */
 509         master->num_chipselect = spi->num_chipselect;
 510         master->mode_bits = spi->mode;
 511         master->flags = spi->flags;
 512         master->bits_per_word_mask = spi->bits_per_word_mask;
 513
 514         /* Attach methods */
 515         master->cleanup = gb_spi_cleanup;
 516         master->setup = gb_spi_setup;
 517         master->transfer_one_message = gb_spi_transfer_one_message;
 518
 519         if (ops && ops->prepare_transfer_hardware) {
 520                 master->prepare_transfer_hardware =
 521                         gb_spi_prepare_transfer_hardware;
 522         }
 523
 524         if (ops && ops->unprepare_transfer_hardware) {
 525                 master->unprepare_transfer_hardware =
 526                         gb_spi_unprepare_transfer_hardware;
 527         }
 528
 529         master->auto_runtime_pm = true;
 530
 531         ret = spi_register_master(master);
 532         if (ret < 0)
 533                 goto exit_spi_put;
 534
 535         /* now, fetch the devices configuration */
 536         for (i = 0; i < spi->num_chipselect; i++) {
 537                 ret = gb_spi_setup_device(spi, i);
 538                 if (ret < 0) {
 539                         dev_err(dev, "failed to allocate spi device %d: %d\n",
 540                                 i, ret);
 541                         goto exit_spi_unregister;
 542                 }
 543         }
 544
 545         return 0;
 546
 547 exit_spi_unregister:
 548         spi_unregister_master(master);
 549 exit_spi_put:
 550         spi_master_put(master);
 551
 552         return ret;
 553 }
 554 EXPORT_SYMBOL_GPL(gb_spilib_master_init);
 555
 556 void gb_spilib_master_exit(struct gb_connection *connection)
 557 {
 558         struct spi_master *master = gb_connection_get_data(connection);
 559
 560         spi_unregister_master(master);
 561         spi_master_put(master);
 562 }
 563 EXPORT_SYMBOL_GPL(gb_spilib_master_exit);
 564
 565 MODULE_LICENSE("GPL v2");