ATHandler.h

00001 /*
00002  * Copyright (c) 2017, Arm Limited and affiliates.
00003  * SPDX-License-Identifier: Apache-2.0
00004  *
00005  * Licensed under the Apache License, Version 2.0 (the "License");
00006  * you may not use this file except in compliance with the License.
00007  * You may obtain a copy of the License at
00008  *
00009  *     http://www.apache.org/licenses/LICENSE-2.0
00010  *
00011  * Unless required by applicable law or agreed to in writing, software
00012  * distributed under the License is distributed on an "AS IS" BASIS,
00013  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00014  * See the License for the specific language governing permissions and
00015  * limitations under the License.
00016  */
00017 
00018 #ifndef AT_HANDLER_H_
00019 #define AT_HANDLER_H_
00020 
00021 #include "platform/mbed_retarget.h"
00022 #include "stdio.h"
00023 
00024 #include "EventQueue.h"
00025 #include "PlatformMutex.h"
00026 #include "nsapi_types.h"
00027 
00028 #include "PlatformMutex.h"
00029 #include "Callback.h"
00030 #include "EventQueue.h"
00031 
00032 namespace mbed {
00033 
00034 class FileHandle;
00035 
00036 /**
00037  * If application calls associated FileHandle only from single thread context
00038   * then locking between AT command and response is not needed. However,
00039   * note that many cellular functions are called indirectly, for example with the socket API.
00040   * If you are unsure, then AT_HANDLER_MUTEX must be defined.
00041   */
00042 #define AT_HANDLER_MUTEX
00043 
00044 extern const char *OK;
00045 extern const char *CRLF;
00046 
00047 #define BUFF_SIZE 16
00048 
00049 /* AT Error types enumeration */
00050 enum DeviceErrorType {
00051     DeviceErrorTypeNoError = 0,
00052     DeviceErrorTypeError,       // AT ERROR
00053     DeviceErrorTypeErrorCMS,    // AT ERROR CMS
00054     DeviceErrorTypeErrorCME     // AT ERROR CME
00055 };
00056 
00057 /* struct used when getting at response error. Defines error code and type */
00058 struct device_err_t {
00059     DeviceErrorType errType;
00060     int errCode;
00061 };
00062 
00063 /** Class ATHandler
00064  *
00065  *  Class for sending AT commands and parsing AT responses.
00066  */
00067 class ATHandler
00068 {
00069 
00070 public:
00071     /** Constructor
00072      *
00073      *  @param fh               file handle used for reading AT responses and writing AT commands
00074      *  @param queue            Event queue used to transfer sigio events to this thread
00075      *  @param timeout          Timeout when reading for AT response
00076      *  @param output_delimiter delimiter used when parsing at responses, "\r" should be used as output_delimiter
00077      */
00078     ATHandler(FileHandle *fh, events::EventQueue &queue, int timeout, const char *output_delimiter);
00079     ~ATHandler();
00080 
00081     /** Return used file handle.
00082      *
00083      *  @return used file handle
00084      */
00085     FileHandle *get_file_handle();
00086 
00087     /** Set file handle, which is used for reading AT responses and writing AT commands
00088      *
00089      *  @param fh file handle used for reading AT responses and writing AT commands
00090      */
00091     void set_file_handle(FileHandle *fh);
00092 
00093     /** Locks the mutex for file handle if AT_HANDLER_MUTEX is defined.
00094      */
00095     void lock();
00096 
00097     /** Unlocks the mutex for file handle if AT_HANDLER_MUTEX is defined.
00098      */
00099     void unlock();
00100 
00101     /** Locks the mutex for file handle if AT_HANDLER_MUTEX is defined and returns the last error.
00102      *
00103      * @return last error that happened when parsing AT responses
00104      */
00105     nsapi_error_t unlock_return_error();
00106 
00107     /** Set the urc callback for urc. If urc is found when parsing AT responses, then call if called.
00108      *
00109      *  @param prefix   Register urc prefix for callback. Urc could be for example "+CMTI: "
00110      *  @param callback Callback, which is called if urc is found in AT response
00111      */
00112     void set_urc_handler(const char *prefix, mbed::Callback<void()> callback);
00113 
00114     ATHandler *_nextATHandler; // linked list
00115 
00116     /** returns the last error while parsing AT responses.
00117      *
00118      *  @return last error
00119      */
00120     nsapi_error_t get_last_error() const;
00121 
00122     /** returns the last device error while parsing AT responses. Actually AT error (CME/CMS).
00123      *
00124      *  @return last error struct device_err_t
00125      */
00126     device_err_t get_last_device_error() const;
00127 
00128     /** Increase reference count. Used for counting references to this instance.
00129      */
00130     void inc_ref_count();
00131 
00132     /** Decrease reference count. Used for counting references to this instance.
00133      */
00134     void dec_ref_count();
00135 
00136     /** Get the current reference count. Used for counting references to this instance.
00137      *
00138      *  @return current reference count
00139      */
00140     int get_ref_count();
00141 
00142     /** Set timeout in milliseconds for AT commands
00143      *
00144      *  @param timeout_milliseconds  Timeout in milliseconds
00145      *  @param default_timeout       Store as default timeout
00146      */
00147     void set_at_timeout(uint32_t timeout_milliseconds, bool default_timeout = false);
00148 
00149     /** Restore timeout to previous timeout. Handy if there is a need to change timeout temporarily.
00150      */
00151     void restore_at_timeout();
00152 
00153     /** Clear pending error flag. By default, error is cleared only in lock().
00154      */
00155     void clear_error();
00156 
00157     /** Tries to find oob's from the AT response. Call the urc callback if one is found.
00158      */
00159     void process_oob();
00160 
00161     /** Set sigio for the current file handle. Sigio event goes through eventqueue so that it's handled in current thread.
00162      */
00163     void set_filehandle_sigio();
00164 
00165     /**
00166      * Flushes the underlying stream
00167      */
00168     void flush();
00169 
00170 protected:
00171     void event();
00172 #ifdef AT_HANDLER_MUTEX
00173     PlatformMutex _fileHandleMutex;
00174 #endif
00175     FileHandle *_fileHandle;
00176 private:
00177 
00178     void set_error(nsapi_error_t err);
00179 
00180     events::EventQueue &_queue;
00181     nsapi_error_t _last_err;
00182     int _last_3gpp_error;
00183     device_err_t  _last_at_err;
00184     uint16_t _oob_string_max_length;
00185     char *_output_delimiter;
00186     uint8_t _output_delimiter_length;
00187 
00188     struct oob_t {
00189         bool matching_to_received;
00190         const char *prefix;
00191         mbed::Callback<void()> cb;
00192         oob_t *next;
00193     };
00194     oob_t *_oobs;
00195     bool _response_terminated;
00196     uint32_t _at_timeout;
00197     uint32_t _previous_at_timeout;
00198 
00199     bool _fh_sigio_set;
00200 
00201     bool _processing;
00202     int32_t _ref_count;
00203 
00204         //*************************************
00205 public:
00206 
00207     /** Starts the command writing by clearing the last error and writing the given command.
00208      *  In case of failure when writing, the last error is set to NSAPI_ERROR_DEVICE_ERROR.
00209      *
00210      *  @param cmd  AT command to be written to modem
00211      */
00212     void cmd_start(const char* cmd);
00213 
00214     /** Writes integer type AT command subparameter. Starts with the delimiter if not the first param after cmd_start.
00215      *  In case of failure when writing, the last error is set to NSAPI_ERROR_DEVICE_ERROR.
00216      *
00217      *   @param param int to be written to modem as AT command subparameter
00218      */
00219     void write_int(int32_t param);
00220 
00221     /** Writes string type AT command subparamater. Quotes are added to surround the given string.
00222      *  Starts with the delimiter if not the first param after cmd_start.
00223      *  In case of failure when writing, the last error is set to NSAPI_ERROR_DEVICE_ERROR.
00224      *
00225      *  @param param string to be written to modem as AT command subparameter
00226      *  @param useQuotations flag indicating whether the string should be included in quotation marks
00227      */
00228     void write_string(const char* param,  bool useQuotations = true);
00229 
00230     /** Stops the AT command by writing command-line terminator CR to mark command as finished.
00231      */
00232     void cmd_stop();
00233 
00234     /** Write bytes without any subparameter delimiters, such as comma.
00235      *  In case of failure when writing, the last error is set to NSAPI_ERROR_DEVICE_ERROR.
00236      *
00237      *  @param data bytes to be written to modem
00238      *  @param len  length of data string
00239      *
00240      *  @return     number of characters successfully written
00241      */
00242     size_t write_bytes(const uint8_t *data, size_t len);
00243 
00244     /** Sets the stop tag for the current scope (response/information response/element)
00245      *  Parameter's reading routines will stop the reading when such tag is found and will set the found flag.
00246      *  Consume routines will read everything until such tag is found.
00247      *
00248      *  @param stop_tag_seq string to be set as stop tag
00249      */
00250     void set_stop_tag(const char *stop_tag_seq);
00251 
00252     /** Sets the delimiter between parameters or between elements of the information response.
00253      *  Parameter's reading routines will stop when such char is read.
00254      *
00255      *  @param delimiter char to be set as _delimiter
00256      */
00257     void set_delimiter(char delimiter);
00258 
00259     /** Sets the delimiter to default value defined by DEFAULT_DELIMITER.
00260      */
00261     void set_default_delimiter();
00262 
00263     /** Consumes the reading buffer up to the delimiter or stop_tag
00264      *
00265      *  @param count number of parameters to be skipped
00266      */
00267     void skip_param(uint32_t count = 1);
00268 
00269     /** Consumes the given length from the reading buffer
00270      *
00271      *  @param len length to be consumed from reading buffer
00272      *  @param count number of parameters to be skipped
00273      */
00274     void skip_param(ssize_t len, uint32_t count);
00275 
00276     /** Reads given number of bytes from receiving buffer without checking any subparameter delimiters, such as comma.
00277      *
00278      *  @param buf output buffer for the read
00279      *  @param len maximum number of bytes to read
00280      *  @return number of successfully read bytes or -1 in case of error
00281      */
00282     ssize_t read_bytes(uint8_t *buf, size_t len);
00283 
00284     /** Reads chars from reading buffer. Terminates with null. Skips the quotation marks.
00285      *  Stops on delimiter or stop tag.
00286      *
00287      *  @param str output buffer for the read
00288      *  @param size maximum number of chars to output
00289      *  @param read_even_stop_tag if true then try to read even if the stop tag was found previously
00290      *  @return length of output string or -1 in case of read timeout before delimiter or stop tag is found
00291      */
00292     ssize_t read_string(char *str, size_t size, bool read_even_stop_tag = false);
00293 
00294     /** Reads as string and converts result to integer. Supports only positive integers.
00295      *
00296      *  @return the positive integer or -1 in case of error.
00297      */
00298     int32_t read_int();
00299 
00300     /**  This looks for necessary matches: prefix, OK, ERROR, URCs and sets the correct scope.
00301      *
00302      *  @param prefix string to be matched from receiving buffer. If not NULL and match succeeds, then scope
00303      *          will be set as information response(info_type)
00304      *  @param stop flag to indicate if we go to information response scope or not.
00305      *        (needed when nothing is expected to be received anymore after the prefix match:
00306      *         sms case: "> ", bc95 reboot case)
00307      */
00308     void resp_start(const char *prefix = NULL, bool stop = false);
00309 
00310     /**  Ends all scopes starting from current scope.
00311      *   Consumes everything until the scope's stop tag is found, then
00312      *   goes to next scope until response scope is ending.
00313      *   Possible sequence:
00314      *   element scope -> information response scope -> response scope
00315      */
00316     void resp_stop();
00317 
00318     /**  Looks for matching the prefix given to resp_start() call.
00319      *   If needed, it ends the scope of a previous information response.
00320      *   Sets the information response scope if new prefix is found and response scope if prefix is not found.
00321      *
00322      *  @return true if new information response is found, false otherwise
00323      */
00324     bool info_resp();
00325 
00326     /**  Looks for matching the start tag.
00327      *   If needed, it ends the scope of a previous element.
00328      *   Sets the element scope if start tag is found and information response scope if start tag is not found.
00329      *
00330      *  @param start_tag tag to be matched to begin parsing an element of an information response
00331      *  @return true if new element is found, false otherwise
00332      */
00333     bool info_elem(char start_tag);
00334 
00335     /**  Consumes the received content until current stop tag is found.
00336      *
00337      *  @return true if stop tag is found, false otherwise
00338      */
00339     bool consume_to_stop_tag();
00340 
00341     /**  Sets _debug_on flag.
00342      *
00343      *  @param enable value to be set for _debug_on flag
00344      */
00345     void enable_debug(bool enable);
00346 
00347     /** Return the last 3GPP error code.
00348      *  @return last 3GPP error code
00349      */
00350     int get_3gpp_error();
00351 
00352 private:
00353 
00354     // should fit any prefix and int
00355     char _recv_buff[BUFF_SIZE];
00356     // reading position
00357     size_t _recv_len;
00358     // reading length
00359     size_t _recv_pos;
00360 
00361     // resp_type: the part of the response that doesn't include the information response (+CMD1,+CMD2..)
00362     //            ends with OK or (CME)(CMS)ERROR
00363     // info_type: the information response part of the response: starts with +CMD1 and ends with CRLF
00364     //            information response contains parameters or subsets of parameters (elements), both separated by comma
00365     // elem_type: subsets of parameters that are part of information response, its parameters are separated by comma
00366     enum ScopeType {RespType, InfoType, ElemType, NotSet};
00367     void set_scope(ScopeType scope_type);
00368     ScopeType _current_scope;
00369 
00370     struct tag_t {
00371         char tag[7];
00372         size_t len;
00373         bool found;
00374     };
00375 
00376     // tag to stop response scope
00377     tag_t _resp_stop;
00378     // tag to stop information response scope
00379     tag_t _info_stop;
00380     // tag to stop element scope
00381     tag_t _elem_stop;
00382     // reference to the stop tag of current scope (resp/info/elem)
00383     tag_t *_stop_tag;
00384 
00385     // delimiter between parameters and also used for delimiting elements of information response
00386     char _delimiter;
00387     // set true on prefix match -> indicates start of an information response or of an element
00388     bool _prefix_matched;
00389     // set true on urc match
00390     bool _urc_matched;
00391     // set true on (CME)(CMS)ERROR
00392     bool _error_found;
00393     // Max length of OK,(CME)(CMS)ERROR and URCs
00394     size_t _max_resp_length;
00395 
00396     // prefix set during resp_start and used to try matching possible information responses
00397     char _info_resp_prefix[BUFF_SIZE];
00398     bool _debug_on;
00399     bool _cmd_start;
00400 
00401     // Gets char from receiving buffer.
00402     // Resets and fills the buffer if all are already read (receiving position equals receiving length).
00403     int get_char();
00404     // Sets to 0 the reading position, reading length and the whole buffer content.
00405     void reset_buffer();
00406     // Reading position set to 0 and buffer's unread content moved to beginning
00407     void rewind_buffer();
00408     // Reads from serial to receiving buffer.
00409     // Returns on first successful read OR on timeout.
00410     void fill_buffer();
00411 
00412     void set_tag(tag_t* tag_dest, const char *tag_seq);
00413 
00414     // Rewinds the receiving buffer and compares it against given str.
00415     bool match(const char* str, size_t size);
00416     // Iterates URCs and checks if they match the receiving buffer content.
00417     // If URC match sets the scope to information response and after urc's cb returns
00418     // finishes the information response scope(consumes to CRLF).
00419     bool match_urc();
00420     // Checks if any of the error strings are matching the receiving buffer content.
00421     bool match_error();
00422     // Checks if current char in buffer matches ch and consumes it,
00423     // if no match lets the buffer unchanged.
00424     bool consume_char(char ch);
00425     // Consumes the received content until tag is found.
00426     // Consumes the tag only if consume_tag flag is true.
00427     bool consume_to_tag(const char *tag, bool consume_tag);
00428     // Checks if receiving buffer contains OK, ERROR, URC or given prefix.
00429     void resp(const char *prefix, bool check_urc);
00430 
00431 
00432     ScopeType get_scope();
00433 
00434     // Consumes to information response stop tag which is CRLF. Sets scope to response.
00435     void information_response_stop();
00436     // Consumes to element stop tag. Sets scope to information response
00437     void information_response_element_stop();
00438 
00439     // Reads the error code if expected and sets it as last error.
00440     void at_error(bool error_code, DeviceErrorType error_type);
00441 
00442     /** Convert AT error code to 3GPP error codes
00443      *  @param err AT error code read from CME/CMS ERROR responses
00444      *  @param error_type error type (CMS/CME/ERROR)
00445      */
00446     void set_3gpp_error(int err, DeviceErrorType error_type);
00447 
00448     bool check_cmd_send();
00449     bool write_char(char c);
00450 
00451     /** Copy content of one char buffer to another buffer and sets NULL terminator
00452      *
00453      *  @param dest                  destination char buffer
00454      *  @param src                   source char buffer
00455      *  @param src_len               number of bytes to copy
00456      *
00457      */
00458     void set_string(char *dest, const char *src, size_t src_len);
00459 
00460     /** Finds occurrence of one char buffer inside another char buffer.
00461      *
00462      * @param dest                  destination char buffer
00463      * @param dest_len              length of dest
00464      * @param src                   string to be searched for
00465      * @param src_len               length of string to be searched for
00466      *
00467      * @return pointer to first occurrence of src in dest
00468      */
00469     const char* mem_str(const char* dest, size_t dest_len, const char* src, size_t src_len);
00470 };
00471 
00472 } // namespace mbed
00473 
00474 #endif //AT_HANDLER_H_