staging/greybus/spilib.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * Greybus SPI library
0004  *
0005  * Copyright 2014-2016 Google Inc.
0006  * Copyright 2014-2016 Linaro Ltd.
0007  */
0008
0009 #include <linux/bitops.h>
0010 #include <linux/kernel.h>
0011 #include <linux/module.h>
0012 #include <linux/slab.h>
0013 #include <linux/greybus.h>
0014 #include <linux/spi/spi.h>
0015
0016 #include "spilib.h"
0017
0018 struct gb_spilib {
0019     struct gb_connection    *connection;
0020     struct device       *parent;
0021     struct spi_transfer *first_xfer;
0022     struct spi_transfer *last_xfer;
0023     struct spilib_ops   *ops;
0024     u32         rx_xfer_offset;
0025     u32         tx_xfer_offset;
0026     u32         last_xfer_size;
0027     unsigned int        op_timeout;
0028     u16         mode;
0029     u16         flags;
0030     u32         bits_per_word_mask;
0031     u8          num_chipselect;
0032     u32         min_speed_hz;
0033     u32         max_speed_hz;
0034 };
0035
0036 #define GB_SPI_STATE_MSG_DONE       ((void *)0)
0037 #define GB_SPI_STATE_MSG_IDLE       ((void *)1)
0038 #define GB_SPI_STATE_MSG_RUNNING    ((void *)2)
0039 #define GB_SPI_STATE_OP_READY       ((void *)3)
0040 #define GB_SPI_STATE_OP_DONE        ((void *)4)
0041 #define GB_SPI_STATE_MSG_ERROR      ((void *)-1)
0042
0043 #define XFER_TIMEOUT_TOLERANCE      200
0044
0045 static struct spi_master *get_master_from_spi(struct gb_spilib *spi)
0046 {
0047     return gb_connection_get_data(spi->connection);
0048 }
0049
0050 static int tx_header_fit_operation(u32 tx_size, u32 count, size_t data_max)
0051 {
0052     size_t headers_size;
0053
0054     data_max -= sizeof(struct gb_spi_transfer_request);
0055     headers_size = (count + 1) * sizeof(struct gb_spi_transfer);
0056
0057     return tx_size + headers_size > data_max ? 0 : 1;
0058 }
0059
0060 static size_t calc_rx_xfer_size(u32 rx_size, u32 *tx_xfer_size, u32 len,
0061                 size_t data_max)
0062 {
0063     size_t rx_xfer_size;
0064
0065     data_max -= sizeof(struct gb_spi_transfer_response);
0066
0067     if (rx_size + len > data_max)
0068         rx_xfer_size = data_max - rx_size;
0069     else
0070         rx_xfer_size = len;
0071
0072     /* if this is a write_read, for symmetry read the same as write */
0073     if (*tx_xfer_size && rx_xfer_size > *tx_xfer_size)
0074         rx_xfer_size = *tx_xfer_size;
0075     if (*tx_xfer_size && rx_xfer_size < *tx_xfer_size)
0076         *tx_xfer_size = rx_xfer_size;
0077
0078     return rx_xfer_size;
0079 }
0080
0081 static size_t calc_tx_xfer_size(u32 tx_size, u32 count, size_t len,
0082                 size_t data_max)
0083 {
0084     size_t headers_size;
0085
0086     data_max -= sizeof(struct gb_spi_transfer_request);
0087     headers_size = (count + 1) * sizeof(struct gb_spi_transfer);
0088
0089     if (tx_size + headers_size + len > data_max)
0090         return data_max - (tx_size + sizeof(struct gb_spi_transfer));
0091
0092     return len;
0093 }
0094
0095 static void clean_xfer_state(struct gb_spilib *spi)
0096 {
0097     spi->first_xfer = NULL;
0098     spi->last_xfer = NULL;
0099     spi->rx_xfer_offset = 0;
0100     spi->tx_xfer_offset = 0;
0101     spi->last_xfer_size = 0;
0102     spi->op_timeout = 0;
0103 }
0104
0105 static bool is_last_xfer_done(struct gb_spilib *spi)
0106 {
0107     struct spi_transfer *last_xfer = spi->last_xfer;
0108
0109     if ((spi->tx_xfer_offset + spi->last_xfer_size == last_xfer->len) ||
0110         (spi->rx_xfer_offset + spi->last_xfer_size == last_xfer->len))
0111         return true;
0112
0113     return false;
0114 }
0115
0116 static int setup_next_xfer(struct gb_spilib *spi, struct spi_message *msg)
0117 {
0118     struct spi_transfer *last_xfer = spi->last_xfer;
0119
0120     if (msg->state != GB_SPI_STATE_OP_DONE)
0121         return 0;
0122
0123     /*
0124      * if we transferred all content of the last transfer, reset values and
0125      * check if this was the last transfer in the message
0126      */
0127     if (is_last_xfer_done(spi)) {
0128         spi->tx_xfer_offset = 0;
0129         spi->rx_xfer_offset = 0;
0130         spi->op_timeout = 0;
0131         if (last_xfer == list_last_entry(&msg->transfers,
0132                          struct spi_transfer,
0133                          transfer_list))
0134             msg->state = GB_SPI_STATE_MSG_DONE;
0135         else
0136             spi->first_xfer = list_next_entry(last_xfer,
0137                               transfer_list);
0138         return 0;
0139     }
0140
0141     spi->first_xfer = last_xfer;
0142     if (last_xfer->tx_buf)
0143         spi->tx_xfer_offset += spi->last_xfer_size;
0144
0145     if (last_xfer->rx_buf)
0146         spi->rx_xfer_offset += spi->last_xfer_size;
0147
0148     return 0;
0149 }
0150
0151 static struct spi_transfer *get_next_xfer(struct spi_transfer *xfer,
0152                       struct spi_message *msg)
0153 {
0154     if (xfer == list_last_entry(&msg->transfers, struct spi_transfer,
0155                     transfer_list))
0156         return NULL;
0157
0158     return list_next_entry(xfer, transfer_list);
0159 }
0160
0161 /* Routines to transfer data */
0162 static struct gb_operation *gb_spi_operation_create(struct gb_spilib *spi,
0163         struct gb_connection *connection, struct spi_message *msg)
0164 {
0165     struct gb_spi_transfer_request *request;
0166     struct spi_device *dev = msg->spi;
0167     struct spi_transfer *xfer;
0168     struct gb_spi_transfer *gb_xfer;
0169     struct gb_operation *operation;
0170     u32 tx_size = 0, rx_size = 0, count = 0, xfer_len = 0, request_size;
0171     u32 tx_xfer_size = 0, rx_xfer_size = 0, len;
0172     u32 total_len = 0;
0173     unsigned int xfer_timeout;
0174     size_t data_max;
0175     void *tx_data;
0176
0177     data_max = gb_operation_get_payload_size_max(connection);
0178     xfer = spi->first_xfer;
0179
0180     /* Find number of transfers queued and tx/rx length in the message */
0181
0182     while (msg->state != GB_SPI_STATE_OP_READY) {
0183         msg->state = GB_SPI_STATE_MSG_RUNNING;
0184         spi->last_xfer = xfer;
0185
0186         if (!xfer->tx_buf && !xfer->rx_buf) {
0187             dev_err(spi->parent,
0188                 "bufferless transfer, length %u\n", xfer->len);
0189             msg->state = GB_SPI_STATE_MSG_ERROR;
0190             return NULL;
0191         }
0192
0193         tx_xfer_size = 0;
0194         rx_xfer_size = 0;
0195
0196         if (xfer->tx_buf) {
0197             len = xfer->len - spi->tx_xfer_offset;
0198             if (!tx_header_fit_operation(tx_size, count, data_max))
0199                 break;
0200             tx_xfer_size = calc_tx_xfer_size(tx_size, count,
0201                              len, data_max);
0202             spi->last_xfer_size = tx_xfer_size;
0203         }
0204
0205         if (xfer->rx_buf) {
0206             len = xfer->len - spi->rx_xfer_offset;
0207             rx_xfer_size = calc_rx_xfer_size(rx_size, &tx_xfer_size,
0208                              len, data_max);
0209             spi->last_xfer_size = rx_xfer_size;
0210         }
0211
0212         tx_size += tx_xfer_size;
0213         rx_size += rx_xfer_size;
0214
0215         total_len += spi->last_xfer_size;
0216         count++;
0217
0218         xfer = get_next_xfer(xfer, msg);
0219         if (!xfer || total_len >= data_max)
0220             msg->state = GB_SPI_STATE_OP_READY;
0221     }
0222
0223     /*
0224      * In addition to space for all message descriptors we need
0225      * to have enough to hold all tx data.
0226      */
0227     request_size = sizeof(*request);
0228     request_size += count * sizeof(*gb_xfer);
0229     request_size += tx_size;
0230
0231     /* Response consists only of incoming data */
0232     operation = gb_operation_create(connection, GB_SPI_TYPE_TRANSFER,
0233                     request_size, rx_size, GFP_KERNEL);
0234     if (!operation)
0235         return NULL;
0236
0237     request = operation->request->payload;
0238     request->count = cpu_to_le16(count);
0239     request->mode = dev->mode;
0240     request->chip_select = dev->chip_select;
0241
0242     gb_xfer = &request->transfers[0];
0243     tx_data = gb_xfer + count;  /* place tx data after last gb_xfer */
0244
0245     /* Fill in the transfers array */
0246     xfer = spi->first_xfer;
0247     while (msg->state != GB_SPI_STATE_OP_DONE) {
0248         int xfer_delay;
0249
0250         if (xfer == spi->last_xfer)
0251             xfer_len = spi->last_xfer_size;
0252         else
0253             xfer_len = xfer->len;
0254
0255         /* make sure we do not timeout in a slow transfer */
0256         xfer_timeout = xfer_len * 8 * MSEC_PER_SEC / xfer->speed_hz;
0257         xfer_timeout += GB_OPERATION_TIMEOUT_DEFAULT;
0258
0259         if (xfer_timeout > spi->op_timeout)
0260             spi->op_timeout = xfer_timeout;
0261
0262         gb_xfer->speed_hz = cpu_to_le32(xfer->speed_hz);
0263         gb_xfer->len = cpu_to_le32(xfer_len);
0264         xfer_delay = spi_delay_to_ns(&xfer->delay, xfer) / 1000;
0265         xfer_delay = clamp_t(u16, xfer_delay, 0, U16_MAX);
0266         gb_xfer->delay_usecs = cpu_to_le16(xfer_delay);
0267         gb_xfer->cs_change = xfer->cs_change;
0268         gb_xfer->bits_per_word = xfer->bits_per_word;
0269
0270         /* Copy tx data */
0271         if (xfer->tx_buf) {
0272             gb_xfer->xfer_flags |= GB_SPI_XFER_WRITE;
0273             memcpy(tx_data, xfer->tx_buf + spi->tx_xfer_offset,
0274                    xfer_len);
0275             tx_data += xfer_len;
0276         }
0277
0278         if (xfer->rx_buf)
0279             gb_xfer->xfer_flags |= GB_SPI_XFER_READ;
0280
0281         if (xfer == spi->last_xfer) {
0282             if (!is_last_xfer_done(spi))
0283                 gb_xfer->xfer_flags |= GB_SPI_XFER_INPROGRESS;
0284             msg->state = GB_SPI_STATE_OP_DONE;
0285             continue;
0286         }
0287
0288         gb_xfer++;
0289         xfer = get_next_xfer(xfer, msg);
0290     }
0291
0292     msg->actual_length += total_len;
0293
0294     return operation;
0295 }
0296
0297 static void gb_spi_decode_response(struct gb_spilib *spi,
0298                    struct spi_message *msg,
0299                    struct gb_spi_transfer_response *response)
0300 {
0301     struct spi_transfer *xfer = spi->first_xfer;
0302     void *rx_data = response->data;
0303     u32 xfer_len;
0304
0305     while (xfer) {
0306         /* Copy rx data */
0307         if (xfer->rx_buf) {
0308             if (xfer == spi->first_xfer)
0309                 xfer_len = xfer->len - spi->rx_xfer_offset;
0310             else if (xfer == spi->last_xfer)
0311                 xfer_len = spi->last_xfer_size;
0312             else
0313                 xfer_len = xfer->len;
0314
0315             memcpy(xfer->rx_buf + spi->rx_xfer_offset, rx_data,
0316                    xfer_len);
0317             rx_data += xfer_len;
0318         }
0319
0320         if (xfer == spi->last_xfer)
0321             break;
0322
0323         xfer = list_next_entry(xfer, transfer_list);
0324     }
0325 }
0326
0327 static int gb_spi_transfer_one_message(struct spi_master *master,
0328                        struct spi_message *msg)
0329 {
0330     struct gb_spilib *spi = spi_master_get_devdata(master);
0331     struct gb_connection *connection = spi->connection;
0332     struct gb_spi_transfer_response *response;
0333     struct gb_operation *operation;
0334     int ret = 0;
0335
0336     spi->first_xfer = list_first_entry_or_null(&msg->transfers,
0337                            struct spi_transfer,
0338                            transfer_list);
0339     if (!spi->first_xfer) {
0340         ret = -ENOMEM;
0341         goto out;
0342     }
0343
0344     msg->state = GB_SPI_STATE_MSG_IDLE;
0345
0346     while (msg->state != GB_SPI_STATE_MSG_DONE &&
0347            msg->state != GB_SPI_STATE_MSG_ERROR) {
0348         operation = gb_spi_operation_create(spi, connection, msg);
0349         if (!operation) {
0350             msg->state = GB_SPI_STATE_MSG_ERROR;
0351             ret = -EINVAL;
0352             continue;
0353         }
0354
0355         ret = gb_operation_request_send_sync_timeout(operation,
0356                                  spi->op_timeout);
0357         if (!ret) {
0358             response = operation->response->payload;
0359             if (response)
0360                 gb_spi_decode_response(spi, msg, response);
0361         } else {
0362             dev_err(spi->parent,
0363                 "transfer operation failed: %d\n", ret);
0364             msg->state = GB_SPI_STATE_MSG_ERROR;
0365         }
0366
0367         gb_operation_put(operation);
0368         setup_next_xfer(spi, msg);
0369     }
0370
0371 out:
0372     msg->status = ret;
0373     clean_xfer_state(spi);
0374     spi_finalize_current_message(master);
0375
0376     return ret;
0377 }
0378
0379 static int gb_spi_prepare_transfer_hardware(struct spi_master *master)
0380 {
0381     struct gb_spilib *spi = spi_master_get_devdata(master);
0382
0383     return spi->ops->prepare_transfer_hardware(spi->parent);
0384 }
0385
0386 static int gb_spi_unprepare_transfer_hardware(struct spi_master *master)
0387 {
0388     struct gb_spilib *spi = spi_master_get_devdata(master);
0389
0390     spi->ops->unprepare_transfer_hardware(spi->parent);
0391
0392     return 0;
0393 }
0394
0395 static int gb_spi_setup(struct spi_device *spi)
0396 {
0397     /* Nothing to do for now */
0398     return 0;
0399 }
0400
0401 static void gb_spi_cleanup(struct spi_device *spi)
0402 {
0403     /* Nothing to do for now */
0404 }
0405
0406 /* Routines to get controller information */
0407
0408 /*
0409  * Map Greybus spi mode bits/flags/bpw into Linux ones.
0410  * All bits are same for now and so these macro's return same values.
0411  */
0412 #define gb_spi_mode_map(mode) mode
0413 #define gb_spi_flags_map(flags) flags
0414
0415 static int gb_spi_get_master_config(struct gb_spilib *spi)
0416 {
0417     struct gb_spi_master_config_response response;
0418     u16 mode, flags;
0419     int ret;
0420
0421     ret = gb_operation_sync(spi->connection, GB_SPI_TYPE_MASTER_CONFIG,
0422                 NULL, 0, &response, sizeof(response));
0423     if (ret < 0)
0424         return ret;
0425
0426     mode = le16_to_cpu(response.mode);
0427     spi->mode = gb_spi_mode_map(mode);
0428
0429     flags = le16_to_cpu(response.flags);
0430     spi->flags = gb_spi_flags_map(flags);
0431
0432     spi->bits_per_word_mask = le32_to_cpu(response.bits_per_word_mask);
0433     spi->num_chipselect = response.num_chipselect;
0434
0435     spi->min_speed_hz = le32_to_cpu(response.min_speed_hz);
0436     spi->max_speed_hz = le32_to_cpu(response.max_speed_hz);
0437
0438     return 0;
0439 }
0440
0441 static int gb_spi_setup_device(struct gb_spilib *spi, u8 cs)
0442 {
0443     struct spi_master *master = get_master_from_spi(spi);
0444     struct gb_spi_device_config_request request;
0445     struct gb_spi_device_config_response response;
0446     struct spi_board_info spi_board = { {0} };
0447     struct spi_device *spidev;
0448     int ret;
0449     u8 dev_type;
0450
0451     request.chip_select = cs;
0452
0453     ret = gb_operation_sync(spi->connection, GB_SPI_TYPE_DEVICE_CONFIG,
0454                 &request, sizeof(request),
0455                 &response, sizeof(response));
0456     if (ret < 0)
0457         return ret;
0458
0459     dev_type = response.device_type;
0460
0461     if (dev_type == GB_SPI_SPI_DEV)
0462         strscpy(spi_board.modalias, "spidev",
0463             sizeof(spi_board.modalias));
0464     else if (dev_type == GB_SPI_SPI_NOR)
0465         strscpy(spi_board.modalias, "spi-nor",
0466             sizeof(spi_board.modalias));
0467     else if (dev_type == GB_SPI_SPI_MODALIAS)
0468         memcpy(spi_board.modalias, response.name,
0469                sizeof(spi_board.modalias));
0470     else
0471         return -EINVAL;
0472
0473     spi_board.mode      = le16_to_cpu(response.mode);
0474     spi_board.bus_num   = master->bus_num;
0475     spi_board.chip_select   = cs;
0476     spi_board.max_speed_hz  = le32_to_cpu(response.max_speed_hz);
0477
0478     spidev = spi_new_device(master, &spi_board);
0479     if (!spidev)
0480         return -EINVAL;
0481
0482     return 0;
0483 }
0484
0485 int gb_spilib_master_init(struct gb_connection *connection, struct device *dev,
0486               struct spilib_ops *ops)
0487 {
0488     struct gb_spilib *spi;
0489     struct spi_master *master;
0490     int ret;
0491     u8 i;
0492
0493     /* Allocate master with space for data */
0494     master = spi_alloc_master(dev, sizeof(*spi));
0495     if (!master) {
0496         dev_err(dev, "cannot alloc SPI master\n");
0497         return -ENOMEM;
0498     }
0499
0500     spi = spi_master_get_devdata(master);
0501     spi->connection = connection;
0502     gb_connection_set_data(connection, master);
0503     spi->parent = dev;
0504     spi->ops = ops;
0505
0506     /* get master configuration */
0507     ret = gb_spi_get_master_config(spi);
0508     if (ret)
0509         goto exit_spi_put;
0510
0511     master->bus_num = -1; /* Allow spi-core to allocate it dynamically */
0512     master->num_chipselect = spi->num_chipselect;
0513     master->mode_bits = spi->mode;
0514     master->flags = spi->flags;
0515     master->bits_per_word_mask = spi->bits_per_word_mask;
0516
0517     /* Attach methods */
0518     master->cleanup = gb_spi_cleanup;
0519     master->setup = gb_spi_setup;
0520     master->transfer_one_message = gb_spi_transfer_one_message;
0521
0522     if (ops && ops->prepare_transfer_hardware) {
0523         master->prepare_transfer_hardware =
0524             gb_spi_prepare_transfer_hardware;
0525     }
0526
0527     if (ops && ops->unprepare_transfer_hardware) {
0528         master->unprepare_transfer_hardware =
0529             gb_spi_unprepare_transfer_hardware;
0530     }
0531
0532     master->auto_runtime_pm = true;
0533
0534     ret = spi_register_master(master);
0535     if (ret < 0)
0536         goto exit_spi_put;
0537
0538     /* now, fetch the devices configuration */
0539     for (i = 0; i < spi->num_chipselect; i++) {
0540         ret = gb_spi_setup_device(spi, i);
0541         if (ret < 0) {
0542             dev_err(dev, "failed to allocate spi device %d: %d\n",
0543                 i, ret);
0544             goto exit_spi_unregister;
0545         }
0546     }
0547
0548     return 0;
0549
0550 exit_spi_put:
0551     spi_master_put(master);
0552
0553     return ret;
0554
0555 exit_spi_unregister:
0556     spi_unregister_master(master);
0557
0558     return ret;
0559 }
0560 EXPORT_SYMBOL_GPL(gb_spilib_master_init);
0561
0562 void gb_spilib_master_exit(struct gb_connection *connection)
0563 {
0564     struct spi_master *master = gb_connection_get_data(connection);
0565
0566     spi_unregister_master(master);
0567 }
0568 EXPORT_SYMBOL_GPL(gb_spilib_master_exit);
0569
0570 MODULE_LICENSE("GPL v2");