Mbed OS Reference | ATHandler.h Source File

 /*
  * Copyright (c) 2017, Arm Limited and affiliates.
  * SPDX-License-Identifier: Apache-2.0
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *     http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
 
 #ifndef AT_HANDLER_H_
 #define AT_HANDLER_H_
 
 #include "platform/mbed_retarget.h"
 
 #include "events/EventQueue.h"
 #include "nsapi_types.h"
 
 #include "Callback.h"
 
 #include <cstdarg>
 
 /**
  * If application calls associated FileHandle only from single thread context
   * then locking between AT command and response is not needed. However,
   * note that many cellular functions are called indirectly, for example with the socket API.
   * If you are unsure, then AT_HANDLER_MUTEX must be defined.
   */
 #define AT_HANDLER_MUTEX
 
 #if defined AT_HANDLER_MUTEX && defined MBED_CONF_RTOS_PRESENT
 #include "ConditionVariable.h"
 #endif
 
 namespace mbed {
 
 class FileHandle;
 
 extern const char *OK;
 extern const char *CRLF;
 
 #define BUFF_SIZE 32
 
 /* AT Error types enumeration */
 enum DeviceErrorType {
     DeviceErrorTypeNoError = 0,
     DeviceErrorTypeError,       // AT ERROR
     DeviceErrorTypeErrorCMS,    // AT ERROR CMS
     DeviceErrorTypeErrorCME     // AT ERROR CME
 };
 
 /** AT response error with error code and type */
 struct device_err_t {
     DeviceErrorType errType;
     int errCode;
 };
 
 /// Class for sending AT commands and parsing AT responses.
 class ATHandler {
 
 public:
     /** Constructor
      *
      *  @param fh               file handle used for reading AT responses and writing AT commands
      *  @param queue            Event queue used to transfer sigio events to this thread
      *  @param timeout          Timeout when reading for AT response
      *  @param output_delimiter delimiter used when parsing at responses, "\r" should be used as output_delimiter
      *  @param send_delay       the minimum delay in ms between the end of last response and the beginning of a new command
      */
     ATHandler(FileHandle *fh, events::EventQueue &queue, uint32_t timeout, const char *output_delimiter, uint16_t send_delay = 0);
     virtual ~ATHandler();
 
     /** Return used file handle.
      *
      *  @return used file handle
      */
     FileHandle *get_file_handle();
 
     /** Get a new ATHandler instance, and update the linked list. Once the use of the ATHandler
      *  has finished, call to close() has to be made
      *
      *  @param fileHandle       filehandle used for reading AT responses and writing AT commands.
      *                          If there is already an ATHandler with the same fileHandle pointer,
      *                          then a pointer to that ATHandler instance will be returned with
      *                          that ATHandler's queue, timeout, delimiter, send_delay and debug_on
      *                          values
      *  @param queue            Event queue used to transfer sigio events to this thread
      *  @param timeout          Timeout when reading for AT response
      *  @param delimiter        delimiter used when parsing at responses, "\r" should be used as output_delimiter
      *  @param send_delay       the minimum delay in ms between the end of last response and the beginning of a new command
      *  @param debug_on         Set true to enable debug traces
      *  @return                 NULL, if fileHandle is not set, or a pointer to an existing ATHandler, if the fileHandle is
      *                          already in use. Otherwise a pointer to a new ATHandler instance is returned
      */
     static ATHandler *get_instance(FileHandle *fileHandle, events::EventQueue &queue, uint32_t timeout,
                                    const char *delimiter, uint16_t send_delay, bool debug_on);
 
     /** Close and delete the current ATHandler instance, if the reference count to it is 0.
      *  Close() can be only called, if the ATHandler was opened with get_instance()
      *
      *  @return NSAPI_ERROR_OK on success, NSAPI_ERROR_PARAMETER on failure
      */
     nsapi_error_t close();
 
     /** Locks the mutex for file handle if AT_HANDLER_MUTEX is defined.
      */
     void lock();
 
     /** Unlocks the mutex for file handle if AT_HANDLER_MUTEX is defined.
      */
     void unlock();
 
     /** Locks the mutex for file handle if AT_HANDLER_MUTEX is defined and returns the last error.
      *
      * @return last error that happened when parsing AT responses
      */
     nsapi_error_t unlock_return_error();
 
     /** Set callback function for URC
      *
      *  @param prefix   URC text to look for, e.g. "+CMTI:". Maximum length is BUFF_SIZE.
      *  @param callback function to call on prefix, or 0 to remove callback
      */
     void set_urc_handler(const char *prefix, Callback<void()> callback);
 
     ATHandler *_nextATHandler; // linked list
 
     /** returns the last error while parsing AT responses.
      *
      *  @return last error
      */
     nsapi_error_t get_last_error() const;
 
     /** returns the last device error while parsing AT responses. Actually AT error (CME/CMS).
      *
      *  @return last error struct device_err_t
      */
     device_err_t get_last_device_error() const;
 
     /** Increase reference count. Used for counting references to this instance.
      *  Note that this should be used with care, if the ATHandler was taken into use
      *  with get_instance()
      */
     void inc_ref_count();
 
     /** Decrease reference count. Used for counting references to this instance.
      *  Note that this should be used with care, if the ATHandler was taken into use
      *  with get_instance()
      */
     void dec_ref_count();
 
     /** Get the current reference count. Used for counting references to this instance.
      *
      *  @return current reference count
      */
     int get_ref_count();
 
     /** Set timeout in milliseconds for AT commands
      *
      *  @param timeout_milliseconds  Timeout in milliseconds
      *  @param default_timeout       Store as default timeout
      */
     void set_at_timeout(uint32_t timeout_milliseconds, bool default_timeout = false);
 
     /** Set timeout in milliseconds for all ATHandlers in the _atHandlers list
      *
      *  @param timeout_milliseconds  Timeout in milliseconds
      *  @param default_timeout       Store as default timeout
      */
     static void set_at_timeout_list(uint32_t timeout_milliseconds, bool default_timeout = false);
 
     /** Restore timeout to previous timeout. Handy if there is a need to change timeout temporarily.
      */
     void restore_at_timeout();
 
     /** Clear pending error flag. By default, error is cleared only in lock().
      */
     void clear_error();
 
     /**
      * Flushes the underlying stream
      */
     void flush();
 
     /** Tries to find oob's from the AT response. Call the urc callback if one is found.
      */
     void process_oob();
 
     /** Set file handle, which is used for reading AT responses and writing AT commands
      *
      *  @param fh file handle used for reading AT responses and writing AT commands
      */
     void set_file_handle(FileHandle *fh);
 
     /** Set is file handle usable. Some situations like after going to data mode, file handle is not usable anymore.
      *  Any items in queue are not to be processed.
      *
      *  @param usable true for usable filehandle
      */
     void set_is_filehandle_usable(bool usable);
 
     /** Synchronize AT command and response handling to modem.
      *
      *  @param timeout_ms ATHandler timeout when trying to sync. Will be restored when function returns.
      *  @return true is synchronization was successful, false in case of failure
      */
     bool sync(int timeout_ms);
 
     /** Sets the delay to be applied before sending any AT command.
      *
      *  @param send_delay the minimum delay in ms between the end of last response and the beginning of a new command
      */
     void set_send_delay(uint16_t send_delay);
 
 protected:
     void event();
 #if defined AT_HANDLER_MUTEX && defined MBED_CONF_RTOS_PRESENT
     rtos::Mutex _fileHandleMutex;
     rtos::ConditionVariable _oobCv;
 #endif
     FileHandle *_fileHandle;
 private:
     /** Remove urc handler from linked list of urc's
      *
      *  @param prefix   Register urc prefix for callback. Urc could be for example "+CMTI: "
      */
     void remove_urc_handler(const char *prefix);
 
     void set_error(nsapi_error_t err);
 
     events::EventQueue &_queue;
     nsapi_error_t _last_err;
     int _last_3gpp_error;
     device_err_t  _last_at_err;
     uint16_t _oob_string_max_length;
     char *_output_delimiter;
 
     struct oob_t {
         const char *prefix;
         int prefix_len;
         Callback<void()> cb;
         oob_t *next;
     };
     oob_t *_oobs;
     uint32_t _at_timeout;
     uint32_t _previous_at_timeout;
 
     uint16_t _at_send_delay;
     uint64_t _last_response_stop;
 
     int32_t _ref_count;
     bool _is_fh_usable;
 
     static ATHandler *_atHandlers;
 
     //*************************************
 public:
 
     /** Starts the command writing by clearing the last error and writing the given command.
      *  In case of failure when writing, the last error is set to NSAPI_ERROR_DEVICE_ERROR.
      *
      *  @param cmd  AT command to be written to modem
      */
     virtual void cmd_start(const char *cmd);
 
     /**
      * @brief cmd_start_stop Starts an AT command, writes given variadic arguments and stops the command. Use this
      *        command when you need multiple response parameters to be handled.
      *        NOTE: Does not lock ATHandler for process!
      *
      * @param cmd AT command in form +<CMD> (will be used also in response reading, no extra chars allowed)
      * @param cmd_chr Char to be added to specific AT command: '?', '=' or ''. Will be used as such so '=1' is valid as well.
      * @param format Format string for variadic arguments to be added to AT command; No separator needed.
      *        Use %d for integer, %s for string and %b for byte string (requires 2 arguments: string and length)
      */
     void cmd_start_stop(const char *cmd, const char *cmd_chr, const char *format = "", ...);
 
     /**
      * @brief at_cmd_str Send an AT command and read a single string response. Locks and unlocks ATHandler for operation
      * @param cmd AT command in form +<CMD> (will be used also in response reading, no extra chars allowed)
      * @param cmd_chr Char to be added to specific AT command: '?', '=' or ''. Will be used as such so '=1' is valid as well.
      * @param resp_buf Response buffer
      * @param resp_buf_size Response buffer size
      * @param format Format string for variadic arguments to be added to AT command; No separator needed.
      *        Use %d for integer, %s for string and %b for byte string (requires 2 arguments: string and length)
      * @return last error that happened when parsing AT responses
      */
     nsapi_error_t at_cmd_str(const char *cmd, const char *cmd_chr, char *resp_buf, size_t resp_buf_size, const char *format = "", ...);
 
     /**
      * @brief at_cmd_int Send an AT command and read a single integer response. Locks and unlocks ATHandler for operation
      * @param cmd AT command in form +<CMD> (will be used also in response reading, no extra chars allowed)
      * @param cmd_chr Char to be added to specific AT command: '?', '=' or ''. Will be used as such so '=1' is valid as well.
      * @param resp Integer to hold response
      * @param format Format string for variadic arguments to be added to AT command; No separator needed.
      *        Use %d for integer, %s for string and %b for byte string (requires 2 arguments: string and length)
      * @return last error that happened when parsing AT responses
      */
     nsapi_error_t at_cmd_int(const char *cmd, const char *cmd_chr, int &resp, const char *format = "", ...);
 
     /**
      * @brief at_cmd_discard Send an AT command and read and discard a response. Locks and unlocks ATHandler for operation
      * @param cmd AT command in form +<CMD> (will be used also in response reading, no extra chars allowed)
      * @param cmd_chr Char to be added to specific AT command: '?', '=' or ''. Will be used as such so '=1' is valid as well.
      * @param format Format string for variadic arguments to be added to AT command; No separator needed.
      *        Use %d for integer, %s for string and %b for byte string (requires 2 arguments: string and length)
      * @return last error that happened when parsing AT responses
      */
     nsapi_error_t at_cmd_discard(const char *cmd, const char *cmd_chr, const char *format = "", ...);
 
 public:
 
     /** Writes integer type AT command subparameter. Starts with the delimiter if not the first param after cmd_start.
      *  In case of failure when writing, the last error is set to NSAPI_ERROR_DEVICE_ERROR.
      *
      *   @param param int to be written to modem as AT command subparameter
      */
     void write_int(int32_t param);
 
     /** Writes string type AT command subparamater. Quotes are added to surround the given string.
      *  Starts with the delimiter if not the first param after cmd_start.
      *  In case of failure when writing, the last error is set to NSAPI_ERROR_DEVICE_ERROR.
      *
      *  @param param string to be written to modem as AT command subparameter
      *  @param useQuotations flag indicating whether the string should be included in quotation marks
      */
     void write_string(const char *param,  bool useQuotations = true);
 
     /** Stops the AT command by writing command-line terminator CR to mark command as finished.
      */
     void cmd_stop();
 
     /** Stops the AT command by writing command-line terminator CR to mark command as finished and reads the OK/ERROR response.
      *
      */
     void cmd_stop_read_resp();
 
     /** Write bytes without any subparameter delimiters, such as comma.
      *  In case of failure when writing, the last error is set to NSAPI_ERROR_DEVICE_ERROR.
      *
      *  @param data bytes to be written to modem
      *  @param len  length of data string
      *
      *  @return     number of characters successfully written
      */
     size_t write_bytes(const uint8_t *data, size_t len);
 
     /** Sets the stop tag for the current scope (response/information response/element)
      *  Parameter's reading routines will stop the reading when such tag is found and will set the found flag.
      *  Consume routines will read everything until such tag is found.
      *
      *  @param stop_tag_seq string to be set as stop tag
      */
     void set_stop_tag(const char *stop_tag_seq);
 
     /** Sets the delimiter between parameters or between elements of the information response.
      *  Parameter's reading routines will stop when such char is read.
      *
      *  @param delimiter char to be set as _delimiter
      */
     void set_delimiter(char delimiter);
 
     /** Sets the delimiter to default value defined by DEFAULT_DELIMITER.
      */
     void set_default_delimiter();
 
     /** Defines behaviour for using or ignoring the delimiter within an AT command
      *
      *  @param use_delimiter indicating if delimiter should be used or not
      */
     void use_delimiter(bool use_delimiter);
 
     /** Consumes the reading buffer up to the delimiter or stop_tag
      *
      *  @param count number of parameters to be skipped
      */
     void skip_param(uint32_t count = 1);
 
     /** Consumes the given length from the reading buffer
      *
      *  @param len length to be consumed from reading buffer
      *  @param count number of parameters to be skipped
      */
     void skip_param(ssize_t len, uint32_t count);
 
     /** Reads given number of bytes from receiving buffer without checking any subparameter delimiters, such as comma.
      *
      *  @param buf output buffer for the read
      *  @param len maximum number of bytes to read
      *  @return number of successfully read bytes or -1 in case of error
      */
     ssize_t read_bytes(uint8_t *buf, size_t len);
 
     /** Reads chars from reading buffer. Terminates with null. Skips the quotation marks.
      *  Stops on delimiter or stop tag.
      *
      *  @param str output buffer for the read
      *  @param size maximum number of chars to output including NULL
      *  @param read_even_stop_tag if true then try to read even if the stop tag was found previously
      *  @return length of output string or -1 in case of read timeout before delimiter or stop tag is found
      */
     ssize_t read_string(char *str, size_t size, bool read_even_stop_tag = false);
 
     /** Reads chars representing hex ascii values and converts them to the corresponding chars.
      *  For example: "4156" to "AV".
      *  Terminates with null. Skips the quotation marks.
      *  Stops on delimiter or stop tag.
      *
      *  @param str output buffer for the read
      *  @param size maximum number of chars to output
      *  @return length of output string or -1 in case of read timeout before delimiter or stop tag is found
      */
     ssize_t read_hex_string(char *str, size_t size);
 
     /** Converts contained chars to their hex ascii value and writes the resulting string to the file handle
      *  For example: "AV" to "4156".
      *
      *  @param str input buffer to be converted to hex ascii
      *  @param size of the input param str
      */
     void write_hex_string(char *str, size_t size);
 
     /** Reads as string and converts result to integer. Supports only non-negative integers.
      *
      *  @return the non-negative integer or -1 in case of error.
      */
     int32_t read_int();
 
     /**  This looks for necessary matches: prefix, OK, ERROR, URCs and sets the correct scope.
      *
      *  @param prefix string to be matched from receiving buffer. If not NULL and match succeeds, then scope
      *          will be set as information response(info_type)
      *  @param stop flag to indicate if we go to information response scope or not.
      *        (needed when nothing is expected to be received anymore after the prefix match:
      *         sms case: "> ", bc95 reboot case)
      */
     void resp_start(const char *prefix = NULL, bool stop = false);
 
     /**  Ends all scopes starting from current scope.
      *   Consumes everything until the scope's stop tag is found, then
      *   goes to next scope until response scope is ending.
      *   URC match is checked during response scope ending,
      *   for every new line / CRLF.
      *
      *
      *   Possible sequence:
      *   element scope -> information response scope -> response scope
      */
     void resp_stop();
 
     /**  Looks for matching the prefix given to resp_start() call.
      *   If needed, it ends the scope of a previous information response.
      *   Sets the information response scope if new prefix is found and response scope if prefix is not found.
      *
      *  @return true if prefix defined for information response is not empty string and is found,
      *          false otherwise.
      */
     bool info_resp();
 
     /**  Looks for matching the start tag.
      *   If needed, it ends the scope of a previous element.
      *   Sets the element scope if start tag is found and information response scope if start tag is not found.
      *
      *  @param start_tag tag to be matched to begin parsing an element of an information response
      *  @return true if new element is found, false otherwise
      */
     bool info_elem(char start_tag);
 
     /**  Consumes the received content until current stop tag is found.
      *
      *  @return true if stop tag is found, false otherwise
      */
     bool consume_to_stop_tag();
 
     /** Return the last 3GPP error code.
      *  @return last 3GPP error code
      */
     int get_3gpp_error();
 
 public: // just for debugging
     /**
      * AT debugging, when enabled will print all data read and written,
      * non-printable chars are printed as "[%d]".
      *
      * AT debug can be enabled at compile time using MBED_CONF_CELLULAR_DEBUG_AT flag or at runtime
      * calling set_debug(). Note that MBED_CONF_MBED_TRACE_ENABLE must also be enabled.
      *
      *  @param debug_on Enable/disable debugging
      */
     void set_debug(bool debug_on);
 
     /**
      * Get degug state set by @ref set_debug
      *
      *  @return current state of debug
      */
     bool get_debug() const;
 
     /** Set debug_on for all ATHandlers in the _atHandlers list
      *
      *  @param debug_on Set true to enable debug traces
      */
     static void set_debug_list(bool debug_on);
 
 private:
 
     // should fit any prefix and int
     char _recv_buff[BUFF_SIZE];
     // reading position
     size_t _recv_len;
     // reading length
     size_t _recv_pos;
 
     // resp_type: the part of the response that doesn't include the information response (+CMD1,+CMD2..)
     //            ends with OK or (CME)(CMS)ERROR
     // info_type: the information response part of the response: starts with +CMD1 and ends with CRLF
     //            information response contains parameters or subsets of parameters (elements), both separated by comma
     // elem_type: subsets of parameters that are part of information response, its parameters are separated by comma
     enum ScopeType {RespType, InfoType, ElemType, NotSet};
     void set_scope(ScopeType scope_type);
     ScopeType _current_scope;
 
     struct tag_t {
         char tag[7];
         size_t len;
         bool found;
     };
 
     // tag to stop response scope
     tag_t _resp_stop;
     // tag to stop information response scope
     tag_t _info_stop;
     // tag to stop element scope
     tag_t _elem_stop;
     // reference to the stop tag of current scope (resp/info/elem)
     tag_t *_stop_tag;
 
     // delimiter between parameters and also used for delimiting elements of information response
     char _delimiter;
     // set true on prefix match -> indicates start of an information response or of an element
     bool _prefix_matched;
     // set true on urc match
     bool _urc_matched;
     // set true on (CME)(CMS)ERROR
     bool _error_found;
     // Max length of OK,(CME)(CMS)ERROR and URCs
     size_t _max_resp_length;
 
     // prefix set during resp_start and used to try matching possible information responses
     char _info_resp_prefix[BUFF_SIZE];
     bool _debug_on;
     bool _cmd_start;
     bool _use_delimiter;
 
     // time when a command or an URC processing was started
     uint64_t _start_time;
     // eventqueue event id
     int _event_id;
 
     char _cmd_buffer[BUFF_SIZE];
 
 private:
     //Handles the arguments from given variadic list
     void handle_args(const char *format, std::va_list list);
 
     //Starts an AT command based on given parameters
     void handle_start(const char *cmd, const char *cmd_chr);
 
     //Checks that ATHandler does not have a pending error condition and filehandle is usable
     bool ok_to_proceed();
 
 private:
     // Gets char from receiving buffer.
     // Resets and fills the buffer if all are already read (receiving position equals receiving length).
     // Returns a next char or -1 on failure (also sets error flag)
     int get_char();
     // Sets to 0 the reading position, reading length and the whole buffer content.
     void reset_buffer();
     // Reading position set to 0 and buffer's unread content moved to beginning
     void rewind_buffer();
     // Calculate remaining time for polling based on request start time and AT timeout.
     // Returns 0 or time in ms for polling.
     int poll_timeout(bool wait_for_timeout = true);
     // Reads from serial to receiving buffer.
     // Returns true on successful read OR false on timeout.
     bool fill_buffer(bool wait_for_timeout = true);
 
     void set_tag(tag_t *tag_dest, const char *tag_seq);
 
     // Rewinds the receiving buffer and compares it against given str.
     bool match(const char *str, size_t size);
     // Iterates URCs and checks if they match the receiving buffer content.
     // If URC match sets the scope to information response and after urc's cb returns
     // finishes the information response scope(consumes to CRLF).
     bool match_urc();
     // Checks if any of the error strings are matching the receiving buffer content.
     bool match_error();
     // Checks if current char in buffer matches ch and consumes it,
     // if no match lets the buffer unchanged.
     bool consume_char(char ch);
     // Consumes the received content until tag is found.
     // Consumes the tag only if consume_tag flag is true.
     bool consume_to_tag(const char *tag, bool consume_tag);
     // Checks if receiving buffer contains OK, ERROR, URC or given prefix.
     void resp(const char *prefix, bool check_urc);
 
 
     ScopeType get_scope();
 
     // Consumes to information response stop tag which is CRLF. Sets scope to response.
     void information_response_stop();
     // Consumes to element stop tag. Sets scope to information response
     void information_response_element_stop();
 
     // Reads the error code if expected and sets it as last error.
     void at_error(bool error_code, DeviceErrorType error_type);
 
     /** Convert AT error code to 3GPP error codes
      *  @param err AT error code read from CME/CMS ERROR responses
      *  @param error_type error type (CMS/CME/ERROR)
      */
     void set_3gpp_error(int err, DeviceErrorType error_type);
 
     bool check_cmd_send();
     size_t write(const void *data, size_t len);
 
     /** Finds occurrence of one char buffer inside another char buffer.
      *
      * @param dest                  destination char buffer
      * @param dest_len              length of dest
      * @param src                   string to be searched for
      * @param src_len               length of string to be searched for
      *
      * @return pointer to first occurrence of src in dest
      */
     const char *mem_str(const char *dest, size_t dest_len, const char *src, size_t src_len);
 
     // check is urc is already added
     bool find_urc_handler(const char *prefix);
 
     // print contents of a buffer to trace log
     enum ATType {
         AT_ERR,
         AT_RX,
         AT_TX
     };
     void debug_print(const char *p, int len, ATType type);
 };
 
 } // namespace mbed
 
 #endif //AT_HANDLER_H_
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