| /* |
| * SPI bridge driver for the Greybus "generic" SPI module. |
| * |
| * Copyright 2014-2015 Google Inc. |
| * Copyright 2014-2015 Linaro Ltd. |
| * |
| * Released under the GPLv2 only. |
| */ |
| |
| #include <linux/bitops.h> |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| #include <linux/slab.h> |
| #include <linux/spi/spi.h> |
| |
| #include "greybus.h" |
| |
| struct gb_spi { |
| struct gb_connection *connection; |
| u16 mode; |
| u16 flags; |
| u32 bits_per_word_mask; |
| u8 num_chipselect; |
| u32 min_speed_hz; |
| u32 max_speed_hz; |
| struct spi_device *spi_devices; |
| }; |
| |
| static struct spi_master *get_master_from_spi(struct gb_spi *spi) |
| { |
| return spi->connection->private; |
| } |
| |
| static int tx_header_fit_operation(u32 tx_size, u32 count, size_t data_max) |
| { |
| size_t headers_size; |
| |
| data_max -= sizeof(struct gb_spi_transfer_request); |
| headers_size = (count + 1) * sizeof(struct gb_spi_transfer); |
| |
| return tx_size + headers_size > data_max ? 0 : 1; |
| } |
| |
| static size_t calc_rx_xfer_size(u32 rx_size, u32 *tx_xfer_size, u32 len, |
| size_t data_max) |
| { |
| size_t rx_xfer_size; |
| |
| data_max -= sizeof(struct gb_spi_transfer_response); |
| |
| if (rx_size + len > data_max) |
| rx_xfer_size = data_max - rx_size; |
| else |
| rx_xfer_size = len; |
| |
| /* if this is a write_read, for symmetry read the same as write */ |
| if (*tx_xfer_size && rx_xfer_size > *tx_xfer_size) |
| rx_xfer_size = *tx_xfer_size; |
| if (*tx_xfer_size && rx_xfer_size < *tx_xfer_size) |
| *tx_xfer_size = rx_xfer_size; |
| |
| return rx_xfer_size; |
| } |
| |
| static size_t calc_tx_xfer_size(u32 tx_size, u32 count, size_t len, |
| size_t data_max) |
| { |
| size_t headers_size; |
| |
| data_max -= sizeof(struct gb_spi_transfer_request); |
| headers_size = (count + 1) * sizeof(struct gb_spi_transfer); |
| |
| if (tx_size + headers_size + len > data_max) |
| return data_max - (tx_size + sizeof(struct gb_spi_transfer)); |
| |
| return len; |
| } |
| |
| /* Routines to transfer data */ |
| static struct gb_operation * |
| gb_spi_operation_create(struct gb_connection *connection, |
| struct spi_message *msg, u32 *total_len) |
| { |
| struct gb_spi_transfer_request *request; |
| struct spi_device *dev = msg->spi; |
| struct spi_transfer *xfer; |
| struct gb_spi_transfer *gb_xfer; |
| struct gb_operation *operation; |
| struct spi_transfer *last_xfer = NULL; |
| u32 tx_size = 0, rx_size = 0, count = 0, xfer_len = 0, request_size; |
| u32 tx_xfer_size = 0, rx_xfer_size = 0, last_xfer_size = 0; |
| size_t data_max; |
| void *tx_data; |
| |
| data_max = gb_operation_get_payload_size_max(connection); |
| |
| /* Find number of transfers queued and tx/rx length in the message */ |
| list_for_each_entry(xfer, &msg->transfers, transfer_list) { |
| if (!xfer->tx_buf && !xfer->rx_buf) { |
| dev_err(&connection->bundle->dev, |
| "bufferless transfer, length %u\n", xfer->len); |
| return NULL; |
| } |
| last_xfer = xfer; |
| |
| tx_xfer_size = 0; |
| rx_xfer_size = 0; |
| |
| if (xfer->tx_buf) { |
| if (!tx_header_fit_operation(tx_size, count, data_max)) |
| break; |
| tx_xfer_size = calc_tx_xfer_size(tx_size, count, |
| xfer->len, data_max); |
| last_xfer_size = tx_xfer_size; |
| } |
| |
| if (xfer->rx_buf) { |
| rx_xfer_size = calc_rx_xfer_size(rx_size, &tx_xfer_size, |
| xfer->len, data_max); |
| last_xfer_size = rx_xfer_size; |
| } |
| |
| tx_size += tx_xfer_size; |
| rx_size += rx_xfer_size; |
| |
| *total_len += last_xfer_size; |
| count++; |
| |
| if (xfer->len != last_xfer_size) |
| break; |
| } |
| |
| /* |
| * In addition to space for all message descriptors we need |
| * to have enough to hold all tx data. |
| */ |
| request_size = sizeof(*request); |
| request_size += count * sizeof(*gb_xfer); |
| request_size += tx_size; |
| |
| /* Response consists only of incoming data */ |
| operation = gb_operation_create(connection, GB_SPI_TYPE_TRANSFER, |
| request_size, rx_size, GFP_KERNEL); |
| if (!operation) |
| return NULL; |
| |
| request = operation->request->payload; |
| request->count = cpu_to_le16(count); |
| request->mode = dev->mode; |
| request->chip_select = dev->chip_select; |
| |
| gb_xfer = &request->transfers[0]; |
| tx_data = gb_xfer + count; /* place tx data after last gb_xfer */ |
| |
| /* Fill in the transfers array */ |
| list_for_each_entry(xfer, &msg->transfers, transfer_list) { |
| if (last_xfer && xfer == last_xfer) |
| xfer_len = last_xfer_size; |
| else |
| xfer_len = xfer->len; |
| |
| gb_xfer->speed_hz = cpu_to_le32(xfer->speed_hz); |
| gb_xfer->len = cpu_to_le32(xfer_len); |
| gb_xfer->delay_usecs = cpu_to_le16(xfer->delay_usecs); |
| gb_xfer->cs_change = xfer->cs_change; |
| gb_xfer->bits_per_word = xfer->bits_per_word; |
| |
| /* Copy tx data */ |
| if (xfer->tx_buf) { |
| gb_xfer->rdwr |= GB_SPI_XFER_WRITE; |
| memcpy(tx_data, xfer->tx_buf, xfer_len); |
| tx_data += xfer_len; |
| } |
| |
| if (xfer->rx_buf) |
| gb_xfer->rdwr |= GB_SPI_XFER_READ; |
| |
| if (last_xfer && xfer == last_xfer) |
| break; |
| |
| gb_xfer++; |
| } |
| |
| return operation; |
| } |
| |
| static void gb_spi_decode_response(struct spi_message *msg, |
| struct gb_spi_transfer_response *response) |
| { |
| struct spi_transfer *xfer; |
| void *rx_data = response->data; |
| |
| list_for_each_entry(xfer, &msg->transfers, transfer_list) { |
| /* Copy rx data */ |
| if (xfer->rx_buf) { |
| memcpy(xfer->rx_buf, rx_data, xfer->len); |
| rx_data += xfer->len; |
| } |
| } |
| } |
| |
| static int gb_spi_transfer_one_message(struct spi_master *master, |
| struct spi_message *msg) |
| { |
| struct gb_spi *spi = spi_master_get_devdata(master); |
| struct gb_connection *connection = spi->connection; |
| struct gb_spi_transfer_response *response; |
| struct gb_operation *operation; |
| u32 len = 0; |
| int ret; |
| |
| operation = gb_spi_operation_create(connection, msg, &len); |
| if (!operation) |
| return -ENOMEM; |
| |
| ret = gb_operation_request_send_sync(operation); |
| if (!ret) { |
| response = operation->response->payload; |
| if (response) |
| gb_spi_decode_response(msg, response); |
| } else { |
| pr_err("transfer operation failed (%d)\n", ret); |
| } |
| |
| gb_operation_put(operation); |
| |
| msg->actual_length = len; |
| msg->status = 0; |
| spi_finalize_current_message(master); |
| |
| return ret; |
| } |
| |
| static int gb_spi_setup(struct spi_device *spi) |
| { |
| /* Nothing to do for now */ |
| return 0; |
| } |
| |
| static void gb_spi_cleanup(struct spi_device *spi) |
| { |
| /* Nothing to do for now */ |
| } |
| |
| |
| /* Routines to get controller information */ |
| |
| /* |
| * Map Greybus spi mode bits/flags/bpw into Linux ones. |
| * All bits are same for now and so these macro's return same values. |
| */ |
| #define gb_spi_mode_map(mode) mode |
| #define gb_spi_flags_map(flags) flags |
| |
| static int gb_spi_get_master_config(struct gb_spi *spi) |
| { |
| struct gb_spi_master_config_response response; |
| u16 mode, flags; |
| int ret; |
| |
| ret = gb_operation_sync(spi->connection, GB_SPI_TYPE_MASTER_CONFIG, |
| NULL, 0, &response, sizeof(response)); |
| if (ret < 0) |
| return ret; |
| |
| mode = le16_to_cpu(response.mode); |
| spi->mode = gb_spi_mode_map(mode); |
| |
| flags = le16_to_cpu(response.flags); |
| spi->flags = gb_spi_flags_map(flags); |
| |
| spi->bits_per_word_mask = le32_to_cpu(response.bits_per_word_mask); |
| spi->num_chipselect = response.num_chipselect; |
| |
| spi->min_speed_hz = le32_to_cpu(response.min_speed_hz); |
| spi->max_speed_hz = le32_to_cpu(response.max_speed_hz); |
| |
| return 0; |
| } |
| |
| static int gb_spi_setup_device(struct gb_spi *spi, u8 cs) |
| { |
| struct spi_master *master = get_master_from_spi(spi); |
| struct gb_spi_device_config_request request; |
| struct gb_spi_device_config_response response; |
| struct spi_board_info spi_board = { {0} }; |
| struct spi_device *spidev = &spi->spi_devices[cs]; |
| int ret; |
| |
| request.chip_select = cs; |
| |
| ret = gb_operation_sync(spi->connection, GB_SPI_TYPE_DEVICE_CONFIG, |
| &request, sizeof(request), |
| &response, sizeof(response)); |
| if (ret < 0) |
| return ret; |
| |
| memcpy(spi_board.modalias, response.name, sizeof(spi_board.modalias)); |
| spi_board.mode = le16_to_cpu(response.mode); |
| spi_board.bus_num = master->bus_num; |
| spi_board.chip_select = cs; |
| spi_board.max_speed_hz = le32_to_cpu(response.max_speed_hz); |
| |
| spidev = spi_new_device(master, &spi_board); |
| if (!spidev) |
| ret = -EINVAL; |
| |
| return 0; |
| } |
| |
| static int gb_spi_init(struct gb_spi *spi) |
| { |
| int ret; |
| |
| /* get master configuration */ |
| ret = gb_spi_get_master_config(spi); |
| if (ret) |
| return ret; |
| |
| spi->spi_devices = kcalloc(spi->num_chipselect, |
| sizeof(struct spi_device), GFP_KERNEL); |
| if (!spi->spi_devices) |
| return -ENOMEM; |
| |
| return ret; |
| } |
| |
| |
| static int gb_spi_connection_init(struct gb_connection *connection) |
| { |
| struct gb_spi *spi; |
| struct spi_master *master; |
| int ret; |
| u8 i; |
| |
| /* Allocate master with space for data */ |
| master = spi_alloc_master(&connection->bundle->dev, sizeof(*spi)); |
| if (!master) { |
| dev_err(&connection->bundle->dev, "cannot alloc SPI master\n"); |
| return -ENOMEM; |
| } |
| |
| spi = spi_master_get_devdata(master); |
| spi->connection = connection; |
| connection->private = master; |
| |
| ret = gb_spi_init(spi); |
| if (ret) |
| goto out_put_master; |
| |
| master->bus_num = -1; /* Allow spi-core to allocate it dynamically */ |
| master->num_chipselect = spi->num_chipselect; |
| master->mode_bits = spi->mode; |
| master->flags = spi->flags; |
| master->bits_per_word_mask = spi->bits_per_word_mask; |
| |
| /* Attach methods */ |
| master->cleanup = gb_spi_cleanup; |
| master->setup = gb_spi_setup; |
| master->transfer_one_message = gb_spi_transfer_one_message; |
| |
| ret = spi_register_master(master); |
| if (ret < 0) |
| goto out_put_master; |
| |
| /* now, fetch the devices configuration */ |
| for (i = 0; i < spi->num_chipselect; i++) { |
| ret = gb_spi_setup_device(spi, i); |
| if (ret < 0) |
| break; |
| } |
| |
| return ret; |
| |
| out_put_master: |
| spi_master_put(master); |
| |
| return ret; |
| } |
| |
| static void gb_spi_connection_exit(struct gb_connection *connection) |
| { |
| struct spi_master *master = connection->private; |
| |
| spi_unregister_master(master); |
| } |
| |
| static struct gb_protocol spi_protocol = { |
| .name = "spi", |
| .id = GREYBUS_PROTOCOL_SPI, |
| .major = GB_SPI_VERSION_MAJOR, |
| .minor = GB_SPI_VERSION_MINOR, |
| .connection_init = gb_spi_connection_init, |
| .connection_exit = gb_spi_connection_exit, |
| .request_recv = NULL, |
| }; |
| |
| gb_builtin_protocol_driver(spi_protocol); |