diff options
Diffstat (limited to 'drivers/staging/greybus/spilib.c')
| -rw-r--r-- | drivers/staging/greybus/spilib.c | 565 |
1 files changed, 565 insertions, 0 deletions
diff --git a/drivers/staging/greybus/spilib.c b/drivers/staging/greybus/spilib.c new file mode 100644 index 000000000000..e97b19148497 --- /dev/null +++ b/drivers/staging/greybus/spilib.c @@ -0,0 +1,565 @@ +/* + * Greybus SPI library + * + * Copyright 2014-2016 Google Inc. + * Copyright 2014-2016 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" +#include "spilib.h" + +struct gb_spilib { + struct gb_connection *connection; + struct device *parent; + struct spi_transfer *first_xfer; + struct spi_transfer *last_xfer; + struct spilib_ops *ops; + u32 rx_xfer_offset; + u32 tx_xfer_offset; + u32 last_xfer_size; + unsigned int op_timeout; + u16 mode; + u16 flags; + u32 bits_per_word_mask; + u8 num_chipselect; + u32 min_speed_hz; + u32 max_speed_hz; +}; + +#define GB_SPI_STATE_MSG_DONE ((void *)0) +#define GB_SPI_STATE_MSG_IDLE ((void *)1) +#define GB_SPI_STATE_MSG_RUNNING ((void *)2) +#define GB_SPI_STATE_OP_READY ((void *)3) +#define GB_SPI_STATE_OP_DONE ((void *)4) +#define GB_SPI_STATE_MSG_ERROR ((void *)-1) + +#define XFER_TIMEOUT_TOLERANCE 200 + +static struct spi_master *get_master_from_spi(struct gb_spilib *spi) +{ + return gb_connection_get_data(spi->connection); +} + +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; +} + +static void clean_xfer_state(struct gb_spilib *spi) +{ + spi->first_xfer = NULL; + spi->last_xfer = NULL; + spi->rx_xfer_offset = 0; + spi->tx_xfer_offset = 0; + spi->last_xfer_size = 0; + spi->op_timeout = 0; +} + +static bool is_last_xfer_done(struct gb_spilib *spi) +{ + struct spi_transfer *last_xfer = spi->last_xfer; + + if ((spi->tx_xfer_offset + spi->last_xfer_size == last_xfer->len) || + (spi->rx_xfer_offset + spi->last_xfer_size == last_xfer->len)) + return true; + + return false; +} + +static int setup_next_xfer(struct gb_spilib *spi, struct spi_message *msg) +{ + struct spi_transfer *last_xfer = spi->last_xfer; + + if (msg->state != GB_SPI_STATE_OP_DONE) + return 0; + + /* + * if we transferred all content of the last transfer, reset values and + * check if this was the last transfer in the message + */ + if (is_last_xfer_done(spi)) { + spi->tx_xfer_offset = 0; + spi->rx_xfer_offset = 0; + spi->op_timeout = 0; + if (last_xfer == list_last_entry(&msg->transfers, + struct spi_transfer, + transfer_list)) + msg->state = GB_SPI_STATE_MSG_DONE; + else + spi->first_xfer = list_next_entry(last_xfer, + transfer_list); + return 0; + } + + spi->first_xfer = last_xfer; + if (last_xfer->tx_buf) + spi->tx_xfer_offset += spi->last_xfer_size; + + if (last_xfer->rx_buf) + spi->rx_xfer_offset += spi->last_xfer_size; + + return 0; +} + +static struct spi_transfer *get_next_xfer(struct spi_transfer *xfer, + struct spi_message *msg) +{ + if (xfer == list_last_entry(&msg->transfers, struct spi_transfer, + transfer_list)) + return NULL; + + return list_next_entry(xfer, transfer_list); +} + +/* Routines to transfer data */ +static struct gb_operation *gb_spi_operation_create(struct gb_spilib *spi, + struct gb_connection *connection, struct spi_message *msg) +{ + 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; + u32 tx_size = 0, rx_size = 0, count = 0, xfer_len = 0, request_size; + u32 tx_xfer_size = 0, rx_xfer_size = 0, len; + u32 total_len = 0; + unsigned int xfer_timeout; + size_t data_max; + void *tx_data; + + data_max = gb_operation_get_payload_size_max(connection); + xfer = spi->first_xfer; + + /* Find number of transfers queued and tx/rx length in the message */ + + while (msg->state != GB_SPI_STATE_OP_READY) { + msg->state = GB_SPI_STATE_MSG_RUNNING; + spi->last_xfer = xfer; + + if (!xfer->tx_buf && !xfer->rx_buf) { + dev_err(spi->parent, + "bufferless transfer, length %u\n", xfer->len); + msg->state = GB_SPI_STATE_MSG_ERROR; + return NULL; + } + + tx_xfer_size = 0; + rx_xfer_size = 0; + + if (xfer->tx_buf) { + len = xfer->len - spi->tx_xfer_offset; + if (!tx_header_fit_operation(tx_size, count, data_max)) + break; + tx_xfer_size = calc_tx_xfer_size(tx_size, count, + len, data_max); + spi->last_xfer_size = tx_xfer_size; + } + + if (xfer->rx_buf) { + len = xfer->len - spi->rx_xfer_offset; + rx_xfer_size = calc_rx_xfer_size(rx_size, &tx_xfer_size, + len, data_max); + spi->last_xfer_size = rx_xfer_size; + } + + tx_size += tx_xfer_size; + rx_size += rx_xfer_size; + + total_len += spi->last_xfer_size; + count++; + + xfer = get_next_xfer(xfer, msg); + if (!xfer || total_len >= data_max) + msg->state = GB_SPI_STATE_OP_READY; + } + + /* + * 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 */ + xfer = spi->first_xfer; + while (msg->state != GB_SPI_STATE_OP_DONE) { + if (xfer == spi->last_xfer) + xfer_len = spi->last_xfer_size; + else + xfer_len = xfer->len; + + /* make sure we do not timeout in a slow transfer */ + xfer_timeout = xfer_len * 8 * MSEC_PER_SEC / xfer->speed_hz; + xfer_timeout += GB_OPERATION_TIMEOUT_DEFAULT; + + if (xfer_timeout > spi->op_timeout) + spi->op_timeout = xfer_timeout; + + 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->xfer_flags |= GB_SPI_XFER_WRITE; + memcpy(tx_data, xfer->tx_buf + spi->tx_xfer_offset, + xfer_len); + tx_data += xfer_len; + } + + if (xfer->rx_buf) + gb_xfer->xfer_flags |= GB_SPI_XFER_READ; + + if (xfer == spi->last_xfer) { + if (!is_last_xfer_done(spi)) + gb_xfer->xfer_flags |= GB_SPI_XFER_INPROGRESS; + msg->state = GB_SPI_STATE_OP_DONE; + continue; + } + + gb_xfer++; + xfer = get_next_xfer(xfer, msg); + } + + msg->actual_length += total_len; + + return operation; +} + +static void gb_spi_decode_response(struct gb_spilib *spi, + struct spi_message *msg, + struct gb_spi_transfer_response *response) +{ + struct spi_transfer *xfer = spi->first_xfer; + void *rx_data = response->data; + u32 xfer_len; + + while (xfer) { + /* Copy rx data */ + if (xfer->rx_buf) { + if (xfer == spi->first_xfer) + xfer_len = xfer->len - spi->rx_xfer_offset; + else if (xfer == spi->last_xfer) + xfer_len = spi->last_xfer_size; + else + xfer_len = xfer->len; + + memcpy(xfer->rx_buf + spi->rx_xfer_offset, rx_data, + xfer_len); + rx_data += xfer_len; + } + + if (xfer == spi->last_xfer) + break; + + xfer = list_next_entry(xfer, transfer_list); + } +} + +static int gb_spi_transfer_one_message(struct spi_master *master, + struct spi_message *msg) +{ + struct gb_spilib *spi = spi_master_get_devdata(master); + struct gb_connection *connection = spi->connection; + struct gb_spi_transfer_response *response; + struct gb_operation *operation; + int ret = 0; + + spi->first_xfer = list_first_entry_or_null(&msg->transfers, + struct spi_transfer, + transfer_list); + if (!spi->first_xfer) { + ret = -ENOMEM; + goto out; + } + + msg->state = GB_SPI_STATE_MSG_IDLE; + + while (msg->state != GB_SPI_STATE_MSG_DONE && + msg->state != GB_SPI_STATE_MSG_ERROR) { + operation = gb_spi_operation_create(spi, connection, msg); + if (!operation) { + msg->state = GB_SPI_STATE_MSG_ERROR; + ret = -EINVAL; + continue; + } + + ret = gb_operation_request_send_sync_timeout(operation, + spi->op_timeout); + if (!ret) { + response = operation->response->payload; + if (response) + gb_spi_decode_response(spi, msg, response); + } else { + dev_err(spi->parent, + "transfer operation failed: %d\n", ret); + msg->state = GB_SPI_STATE_MSG_ERROR; + } + + gb_operation_put(operation); + setup_next_xfer(spi, msg); + } + +out: + msg->status = ret; + clean_xfer_state(spi); + spi_finalize_current_message(master); + + return ret; +} + +static int gb_spi_prepare_transfer_hardware(struct spi_master *master) +{ + struct gb_spilib *spi = spi_master_get_devdata(master); + + return spi->ops->prepare_transfer_hardware(spi->parent); +} + +static int gb_spi_unprepare_transfer_hardware(struct spi_master *master) +{ + struct gb_spilib *spi = spi_master_get_devdata(master); + + spi->ops->unprepare_transfer_hardware(spi->parent); + + return 0; +} + +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_spilib *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_spilib *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; + int ret; + u8 dev_type; + + 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; + + dev_type = response.device_type; + + if (dev_type == GB_SPI_SPI_DEV) + strlcpy(spi_board.modalias, "spidev", + sizeof(spi_board.modalias)); + else if (dev_type == GB_SPI_SPI_NOR) + strlcpy(spi_board.modalias, "spi-nor", + sizeof(spi_board.modalias)); + else if (dev_type == GB_SPI_SPI_MODALIAS) + memcpy(spi_board.modalias, response.name, + sizeof(spi_board.modalias)); + else + return -EINVAL; + + 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) + return -EINVAL; + + return 0; +} + +int gb_spilib_master_init(struct gb_connection *connection, struct device *dev, + struct spilib_ops *ops) +{ + struct gb_spilib *spi; + struct spi_master *master; + int ret; + u8 i; + + /* Allocate master with space for data */ + master = spi_alloc_master(dev, sizeof(*spi)); + if (!master) { + dev_err(dev, "cannot alloc SPI master\n"); + return -ENOMEM; + } + + spi = spi_master_get_devdata(master); + spi->connection = connection; + gb_connection_set_data(connection, master); + spi->parent = dev; + spi->ops = ops; + + /* get master configuration */ + ret = gb_spi_get_master_config(spi); + if (ret) + goto exit_spi_put; + + 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; + + if (ops && ops->prepare_transfer_hardware) { + master->prepare_transfer_hardware = + gb_spi_prepare_transfer_hardware; + } + + if (ops && ops->unprepare_transfer_hardware) { + master->unprepare_transfer_hardware = + gb_spi_unprepare_transfer_hardware; + } + + master->auto_runtime_pm = true; + + ret = spi_register_master(master); + if (ret < 0) + goto exit_spi_put; + + /* now, fetch the devices configuration */ + for (i = 0; i < spi->num_chipselect; i++) { + ret = gb_spi_setup_device(spi, i); + if (ret < 0) { + dev_err(dev, "failed to allocate spi device %d: %d\n", + i, ret); + goto exit_spi_unregister; + } + } + + return 0; + +exit_spi_unregister: + spi_unregister_master(master); +exit_spi_put: + spi_master_put(master); + + return ret; +} +EXPORT_SYMBOL_GPL(gb_spilib_master_init); + +void gb_spilib_master_exit(struct gb_connection *connection) +{ + struct spi_master *master = gb_connection_get_data(connection); + + spi_unregister_master(master); + spi_master_put(master); +} +EXPORT_SYMBOL_GPL(gb_spilib_master_exit); + +MODULE_LICENSE("GPL v2"); |