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#include <obd2/obd2.h>
#include <bitfield/bitfield.h>
#include <string.h>
#include <limits.h>
#include <stddef.h>
#include <sys/param.h>
#define ARBITRATION_ID_OFFSET 0x8
#define MODE_RESPONSE_OFFSET 0x40
#define NEGATIVE_RESPONSE_MODE 0x7f
#define MAX_DIAGNOSTIC_PAYLOAD_SIZE 6
#define MODE_BYTE_INDEX 0
#define PID_BYTE_INDEX 1
#define NEGATIVE_RESPONSE_MODE_INDEX 1
#define NEGATIVE_RESPONSE_NRC_INDEX 2
DiagnosticShims diagnostic_init_shims(LogShim log,
SendCanMessageShim send_can_message,
SetTimerShim set_timer) {
DiagnosticShims shims = {
log: log,
send_can_message: send_can_message,
set_timer: set_timer
};
return shims;
}
DiagnosticRequestHandle diagnostic_request(DiagnosticShims* shims,
DiagnosticRequest* request, DiagnosticResponseReceived callback) {
DiagnosticRequestHandle handle = {
request: *request,
callback: callback,
success: false,
completed: false
};
uint8_t payload[MAX_DIAGNOSTIC_PAYLOAD_SIZE];
payload[MODE_BYTE_INDEX] = request->mode;
if(request->pid_length > 0) {
// TODO may need to flip the byte order
copy_bytes_right_aligned((uint8_t*)&request->pid, sizeof(request->pid),
PID_BYTE_INDEX, request->pid_length, payload, sizeof(payload));
}
if(request->payload_length > 0) {
memcpy(&payload[PID_BYTE_INDEX + request->pid_length],
request->payload, request->payload_length);
}
handle.isotp_shims = isotp_init_shims(shims->log,
shims->send_can_message,
shims->set_timer);
handle.isotp_send_handle = isotp_send(&handle.isotp_shims,
request->arbitration_id, payload,
1 + request->payload_length + request->pid_length,
NULL);
handle.isotp_receive_handle = isotp_receive(&handle.isotp_shims,
request->arbitration_id + ARBITRATION_ID_OFFSET,
NULL);
// TODO notes on multi frame:
// TODO what are the timers for exactly?
//
// when sending multi frame, send 1 frame, wait for a response
// if it says send all, send all right away
// if it says flow control, set the time for the next send
// instead of creating a timer with an async callback, add a process_handle
// function that's called repeatedly in the main loop - if it's time to
// send, we do it. so there's a process_handle_send and receive_can_frame
// that are just called continuously from the main loop. it's a waste of a
// few cpu cycles but it may be more natural than callbacks.
//
// what woudl a timer callback look like...it would need to pass the handle
// and that's all. seems like a context void* would be able to capture all
// of the information but arg, memory allocation. look at how it's done in
// the other library again
//
return handle;
}
DiagnosticRequestHandle diagnostic_request_pid(DiagnosticShims* shims,
DiagnosticPidRequestType pid_request_type, uint16_t arbitration_id,
uint16_t pid, DiagnosticResponseReceived callback) {
DiagnosticRequest request = {
arbitration_id: arbitration_id,
mode: pid_request_type == DIAGNOSTIC_STANDARD_PID ? 0x1 : 0x22,
pid: pid,
pid_length: pid_request_type == DIAGNOSTIC_STANDARD_PID ? 1 : 2
};
return diagnostic_request(shims, &request, callback);
}
static bool handle_negative_response(IsoTpMessage* message,
DiagnosticResponse* response, DiagnosticShims* shims) {
bool response_was_negative = false;
if(response->mode == NEGATIVE_RESPONSE_MODE) {
response_was_negative = true;
if(message->size > NEGATIVE_RESPONSE_MODE_INDEX) {
response->mode = message->payload[NEGATIVE_RESPONSE_MODE_INDEX];
}
if(message->size > NEGATIVE_RESPONSE_NRC_INDEX) {
response->negative_response_code = message->payload[NEGATIVE_RESPONSE_NRC_INDEX];
}
response->success = false;
response->completed = true;
}
return response_was_negative;
}
static bool handle_positive_response(DiagnosticRequestHandle* handle,
IsoTpMessage* message, DiagnosticResponse* response,
DiagnosticShims* shims) {
bool response_was_positive = false;
if(response->mode == handle->request.mode + MODE_RESPONSE_OFFSET) {
response_was_positive = true;
// hide the "response" version of the mode from the user
// if it matched
response->mode = handle->request.mode;
if(handle->request.pid_length > 0 && message->size > 1) {
if(handle->request.pid_length == 2) {
response->pid = *(uint16_t*)&message->payload[PID_BYTE_INDEX];
if(BYTE_ORDER == LITTLE_ENDIAN) {
response->pid = __builtin_bswap32(response->pid << 16);
}
} else {
response->pid = message->payload[PID_BYTE_INDEX];
}
}
uint8_t payload_index = 1 + handle->request.pid_length;
response->payload_length = message->size - payload_index;
if(response->payload_length > 0) {
memcpy(response->payload, &message->payload[payload_index],
response->payload_length);
}
response->success = true;
response->completed = true;
}
return response_was_positive;
}
DiagnosticResponse diagnostic_receive_can_frame(DiagnosticShims* shims,
DiagnosticRequestHandle* handle, const uint16_t arbitration_id,
const uint8_t data[], const uint8_t size) {
DiagnosticResponse response = {
arbitration_id: arbitration_id,
success: false,
completed: false
};
if(!handle->isotp_send_handle.completed) {
isotp_continue_send(&handle->isotp_shims,
&handle->isotp_send_handle, arbitration_id, data, size);
} else if(!handle->isotp_receive_handle.completed) {
IsoTpMessage message = isotp_continue_receive(&handle->isotp_shims,
&handle->isotp_receive_handle, arbitration_id, data, size);
if(message.completed) {
if(message.size > 0) {
response.mode = message.payload[0];
if(handle_negative_response(&message, &response, shims)) {
shims->log("Received a negative response to mode %d on arb ID 0x%x",
response.mode, response.arbitration_id);
handle->success = true;
handle->completed = true;
} else if(handle_positive_response(handle, &message, &response,
shims)) {
shims->log("Received a positive mode %d response on arb ID 0x%x",
response.mode, response.arbitration_id);
handle->success = true;
handle->completed = true;
} else {
shims->log("Response was for a mode 0x%x request, not our mode 0x%x request",
response.mode - MODE_RESPONSE_OFFSET,
handle->request.mode);
}
}
if(handle->completed && handle->callback != NULL) {
handle->callback(&response);
}
}
} else {
shims->log("Mode %d request to arb ID 0x%x is already completed",
handle->request.mode, handle->request.arbitration_id);
}
return response;
}
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