author | lbessard |
Mon, 23 Mar 2009 16:26:13 +0100 | |
changeset 323 | 9f07f0d429df |
parent 300 | 7f7912ae5ee8 |
child 329 | 22e65b8e20f4 |
permissions | -rw-r--r-- |
/* * Python Asynchronous execution code * * PLC put python commands in a fifo, respecting execution order * with the help of C pragmas inserted in python_eval FB code * * Buffer content is read asynchronously, (from non real time part), * commands are executed and result stored for later use by PLC. * * In this implementation, fifo is a list of pointer to python_eval * function blocks structures. Some local variables have been added in * python_eval interface. We use those local variables as buffer and state * flags. * * */ #include "iec_types_all.h" #include "POUS.h" #include <string.h> /* The fifo (fixed size, as number of FB is fixed) */ static PYTHON_EVAL* EvalFBs[%(python_eval_fb_count)d]; /* Producer and consumer cursors */ static int Current_PLC_EvalFB; static int Current_Python_EvalFB; /* A global IEC-Python gateway state, for use inside python_eval FBs*/ static int PythonState; #define PYTHON_LOCKED_BY_PYTHON 0 #define PYTHON_LOCKED_BY_PLC 1 #define PYTHON_MUSTWAKEUP 2 #define PYTHON_FINISHED 4 /* Each python_eval FunctionBlock have it own state */ #define PYTHON_FB_FREE 0 #define PYTHON_FB_REQUESTED 1 #define PYTHON_FB_PROCESSING 2 #define PYTHON_FB_ANSWERED 3 int WaitPythonCommands(void); void UnBlockPythonCommands(void); int TryLockPython(void); void UnLockPython(void); void LockPython(void); void __init_python() { int i; /* Initialize cursors */ Current_Python_EvalFB = 0; Current_PLC_EvalFB = 0; PythonState = PYTHON_LOCKED_BY_PYTHON; for(i = 0; i < %(python_eval_fb_count)d; i++) EvalFBs[i] = NULL; } void __cleanup_python() { PythonState = PYTHON_FINISHED; UnBlockPythonCommands(); } void __retrieve_python() { /* Check Python thread is not being * modifying internal python_eval data */ PythonState = TryLockPython() ? PYTHON_LOCKED_BY_PLC : PYTHON_LOCKED_BY_PYTHON; /* If python thread _is_ in, then PythonState remains PYTHON_LOCKED_BY_PYTHON * and python_eval will no do anything */ } void __publish_python() { if(PythonState & PYTHON_LOCKED_BY_PLC){ /* If runnig PLC did push something in the fifo*/ if(PythonState & PYTHON_MUSTWAKEUP){ /* WakeUp python thread */ UnBlockPythonCommands(); } UnLockPython(); } } /** * Called by the PLC, each time a python_eval * FB instance is executed */ void __PythonEvalFB(int poll, PYTHON_EVAL* data__) { /* detect rising edge on TRIG to trigger evaluation */ if(((data__->TRIG && !data__->TRIGM1) || /* polling is equivalent to trig on value rather than on rising edge*/ (poll && data__->TRIG )) && /* trig only if not already trigged */ data__->TRIGGED == 0){ /* mark as trigged */ data__->TRIGGED = 1; /* make a safe copy of the code */ data__->PREBUFFER = data__->CODE; } /* retain value for next rising edge detection */ data__->TRIGM1 = data__->TRIG; /* python thread is not in ? */ if( PythonState & PYTHON_LOCKED_BY_PLC){ /* if some answer are waiting, publish*/ if(data__->STATE == PYTHON_FB_ANSWERED){ /* Copy buffer content into result*/ data__->RESULT = data__->BUFFER; /* signal result presece to PLC*/ data__->ACK = 1; /* Mark as free */ data__->STATE = PYTHON_FB_FREE; /* mark as not trigged */ if(!poll) data__->TRIGGED = 0; /*printf("__PythonEvalFB pop %%d - %%*s\n",Current_PLC_EvalFB, data__->BUFFER.len, data__->BUFFER.body);*/ }else if(poll){ /* when in polling, no answer == ack down */ data__->ACK = 0; } /* got the order to act ?*/ if(data__->TRIGGED == 1 && /* and not already being processed */ data__->STATE == PYTHON_FB_FREE) { /* Enter the block in the fifo /* Don't have to check if fifo cell is free * as fifo size == FB count, and a FB cannot * be requested twice */ EvalFBs[Current_PLC_EvalFB] = data__; /* copy into BUFFER local*/ data__->BUFFER = data__->PREBUFFER; /* Set ACK pin to low so that we can set a rising edge on result */ if(!poll){ /* when not polling, a new answer imply reseting ack*/ data__->ACK = 0; }else{ /* when in polling, acting reset trigger */ data__->TRIGGED = 0; } /* Mark FB busy */ data__->STATE = PYTHON_FB_REQUESTED; /* Have to wakeup python thread in case he was asleep */ PythonState |= PYTHON_MUSTWAKEUP; /*printf("__PythonEvalFB push %%d - %%*s\n",Current_PLC_EvalFB, data__->BUFFER.len, data__->BUFFER.body);*/ /* Get a new line */ Current_PLC_EvalFB = (Current_PLC_EvalFB + 1) %% %(python_eval_fb_count)d; } } } char* PythonIterator(char* result) { char* next_command; PYTHON_EVAL* data__; //printf("PythonIterator result %%s\n", result); /* take python mutex to prevent changing PLC data while PLC running */ LockPython(); /* Get current FB */ data__ = EvalFBs[Current_Python_EvalFB]; if(data__ && /* may be null at first run */ data__->STATE == PYTHON_FB_PROCESSING){ /* some answer awaited*/ /* If result not None */ if(result){ /* Get results len */ data__->BUFFER.len = strlen(result); /* prevent results overrun */ if(data__->BUFFER.len > STR_MAX_LEN) { data__->BUFFER.len = STR_MAX_LEN; /* TODO : signal error */ } /* Copy results to buffer */ strncpy(data__->BUFFER.body, result, data__->BUFFER.len); }else{ data__->BUFFER.len = 0; } /* remove block from fifo*/ EvalFBs[Current_Python_EvalFB] = NULL; /* Mark block as answered */ data__->STATE = PYTHON_FB_ANSWERED; /* Get a new line */ Current_Python_EvalFB = (Current_Python_EvalFB + 1) %% %(python_eval_fb_count)d; //printf("PythonIterator ++ Current_Python_EvalFB %%d\n", Current_Python_EvalFB); } /* while next slot is empty */ while(((data__ = EvalFBs[Current_Python_EvalFB]) == NULL) || /* or doesn't contain command */ data__->STATE != PYTHON_FB_REQUESTED) { UnLockPython(); /* wait next FB to eval */ //printf("PythonIterator wait\n"); WaitPythonCommands(); /*emergency exit*/ if(PythonState & PYTHON_FINISHED) return NULL; LockPython(); } /* Mark block as processing */ data__->STATE = PYTHON_FB_PROCESSING; //printf("PythonIterator\n"); /* make BUFFER a null terminated string */ data__->BUFFER.body[data__->BUFFER.len] = 0; /* next command is BUFFER */ next_command = data__->BUFFER.body; /* free python mutex */ UnLockPython(); /* return the next command to eval */ return next_command; }