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Diffstat (limited to 'include/osmocom/core/soft_uart.h')
| -rw-r--r-- | include/osmocom/core/soft_uart.h | 149 |
1 files changed, 149 insertions, 0 deletions
diff --git a/include/osmocom/core/soft_uart.h b/include/osmocom/core/soft_uart.h new file mode 100644 index 00000000..afc6ad6d --- /dev/null +++ b/include/osmocom/core/soft_uart.h @@ -0,0 +1,149 @@ +#pragma once + +/*! \file soft_uart.h + * Software UART implementation. */ +/* + * (C) 2022 by Harald Welte <laforge@gnumonks.org> + * (C) 2023 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de> + * + * All Rights Reserved + * + * SPDX-License-Identifier: GPL-2.0+ + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + */ + +#include <stdint.h> +#include <stdbool.h> + +#include <osmocom/core/bits.h> +#include <osmocom/core/msgb.h> + +/*! Parity mode. + * https://en.wikipedia.org/wiki/Parity_bit */ +enum osmo_soft_uart_parity_mode { + OSMO_SUART_PARITY_NONE, /*!< No parity bit */ + OSMO_SUART_PARITY_EVEN, /*!< Even parity */ + OSMO_SUART_PARITY_ODD, /*!< Odd parity */ + OSMO_SUART_PARITY_MARK, /*!< Always 1 */ + OSMO_SUART_PARITY_SPACE, /*!< Always 0 */ + _OSMO_SUART_PARITY_NUM +}; + +/*! Flags passed to the application. */ +enum osmo_soft_uart_flags { + OSMO_SUART_F_FRAMING_ERROR = (1 << 0), /*!< Framing error occurred */ + OSMO_SUART_F_PARITY_ERROR = (1 << 1), /*!< Parity error occurred */ + OSMO_SUART_F_BREAK = (1 << 2), /*!< Break condition (not implemented) */ +}; + +/*! Modem status "line" flags. + * https://en.wikipedia.org/wiki/RS-232#Data_and_control_signals */ +enum osmo_soft_uart_status { + OSMO_SUART_STATUS_F_DTR = (1 << 0), /*!< Data Terminal Ready */ + OSMO_SUART_STATUS_F_DCD = (1 << 1), /*!< Data Carrier Detect */ + OSMO_SUART_STATUS_F_DSR = (1 << 2), /*!< Data Set Ready */ + OSMO_SUART_STATUS_F_RI = (1 << 3), /*!< Ring Indicator */ + OSMO_SUART_STATUS_F_RTS_RTR = (1 << 4), /*!< Request To Send or Ready To Receive */ + OSMO_SUART_STATUS_F_CTS = (1 << 5), /*!< Clear To Send */ +}; + +/*! Flow control mode. + * https://en.wikipedia.org/wiki/Flow_control_(data)#Hardware_flow_control */ +enum osmo_soft_uart_flow_ctrl_mode { + /*! No flow control */ + OSMO_SUART_FLOW_CTRL_NONE, + /*! DTR/DSR flow control: Tx if DSR is active and drop DTR if cannot Rx anymore. */ + OSMO_SUART_FLOW_CTRL_DTR_DSR, + /*! RTS/CTS flow control: Tx if CTS is active and drop RTS if cannot Rx anymore. + * The technically correct name would be RTR/CTS, because the RTS signal actually + * indicates readiness to *receive* data (Ready To Receive), and not really used + * to request a transmission (Request To Send) nowadays. Alternatively, the RTS + * signal can be interpreted as "Request To Send to me". */ + OSMO_SUART_FLOW_CTRL_RTS_CTS, +}; + +/*! Configuration for a soft-UART. */ +struct osmo_soft_uart_cfg { + /*! Number of data bits (typically 5, 6, 7 or 8). */ + uint8_t num_data_bits; + /*! Number of stop bits (typically 1 or 2). */ + uint8_t num_stop_bits; + /*! Parity mode (none, even, odd, space, mark). */ + enum osmo_soft_uart_parity_mode parity_mode; + /*! Size of the receive buffer; UART will buffer up to that number + * of characters before calling the receive call-back. */ + unsigned int rx_buf_size; + /*! Receive timeout; UART will flush the receive buffer via the receive call-back + * after indicated number of milliseconds, even if it is not full yet. */ + unsigned int rx_timeout_ms; + + /*! Opaque application-private data; passed to call-backs. */ + void *priv; + + /*! Receive call-back of the application. + * + * Called if at least one of the following conditions is met: + * a) rx_buf_size characters were received (Rx buffer is full); + * b) rx_timeout_ms expired and Rx buffer is not empty; + * c) a parity or framing error is occurred. + * + * \param[in] priv opaque application-private data. + * \param[in] rx_data msgb holding the received data. + * Must be free()ed by the application. + * \param[in] flags bit-mask of OSMO_SUART_F_*. */ + void (*rx_cb)(void *priv, struct msgb *rx_data, unsigned int flags); + + /*! Transmit call-back of the application. + * + * The implementation is expected to provide at most tx_data->data_len + * characters (the actual amount is determined by the number of requested + * bits and the effective UART configuration). + * + * \param[in] priv opaque application-private data. + * \param[inout] tx_data msgb for writing to be transmitted data. */ + void (*tx_cb)(void *priv, struct msgb *tx_data); + + /*! Modem status line change call-back. + * \param[in] priv opaque application-private data. + * \param[in] status updated status; bit-mask of OSMO_SUART_STATUS_F_*. */ + void (*status_change_cb)(void *priv, unsigned int status); + + /*! "Hardware" flow control mode. */ + enum osmo_soft_uart_flow_ctrl_mode flow_ctrl_mode; +}; + +extern const struct osmo_soft_uart_cfg osmo_soft_uart_default_cfg; + +struct osmo_soft_uart; + +struct osmo_soft_uart *osmo_soft_uart_alloc(void *ctx, const char *name, + const struct osmo_soft_uart_cfg *cfg); +void osmo_soft_uart_free(struct osmo_soft_uart *suart); +int osmo_soft_uart_configure(struct osmo_soft_uart *suart, const struct osmo_soft_uart_cfg *cfg); + +const char *osmo_soft_uart_get_name(const struct osmo_soft_uart *suart); +void osmo_soft_uart_set_name(struct osmo_soft_uart *suart, const char *name); + +int osmo_soft_uart_set_rx(struct osmo_soft_uart *suart, bool enable); +int osmo_soft_uart_set_tx(struct osmo_soft_uart *suart, bool enable); + +int osmo_soft_uart_rx_ubits(struct osmo_soft_uart *suart, const ubit_t *ubits, size_t n_ubits); +int osmo_soft_uart_tx_ubits(struct osmo_soft_uart *suart, ubit_t *ubits, size_t n_ubits); + +unsigned int osmo_soft_uart_get_status(const struct osmo_soft_uart *suart); +int osmo_soft_uart_set_status(struct osmo_soft_uart *suart, unsigned int status); +void osmo_soft_uart_set_status_line(struct osmo_soft_uart *suart, + enum osmo_soft_uart_status line, + bool active); + +void osmo_soft_uart_flush_rx(struct osmo_soft_uart *suart); |