New checksum functions

can/common.cc

@@ -69,6 +69,7 @@ unsigned int chrysler_checksum(unsigned int address, uint64_t d, int l) {
 
 // Static lookup table for fast computation of CRC8 poly 0x2F, aka 8H2F/AUTOSAR
 uint8_t crc8_lut_8h2f[256];
+uint8_t crc8_lut_d5[256];
 
 void gen_crc_lookup_table(uint8_t poly, uint8_t crc_lut[]) {
   uint8_t crc;
@@ -90,6 +91,7 @@ void init_crc_lookup_tables() {
   // At init time, set up static lookup tables for fast CRC computation.
 
   gen_crc_lookup_table(0x2F, crc8_lut_8h2f);    // CRC-8 8H2F/AUTOSAR for Volkswagen
+  gen_crc_lookup_table(0xD5, crc8_lut_d5);      // CRC-8 for pedal
 }
 
 unsigned int volkswagen_crc(unsigned int address, uint64_t d, int l) {
@@ -190,6 +192,16 @@ unsigned int pedal_checksum(uint64_t d, int l) {
   return crc;
 }
 
+unsigned int ocelot_checksum(uint64_t d, int l) {
+  uint8_t crc = 0xFF; // Standard init value for CRC8
+
+  // CRC the payload, skipping over the first byte where the CRC lives.
+  for (int i = 1; i < l; i++) {
+    crc ^= (d >> (i*8)) & 0xFF;
+    crc = crc8_lut_d5[crc];
+  }
+  return crc;
+}
 
 uint64_t read_u64_be(const uint8_t* v) {
   return (((uint64_t)v[0] << 56)

can/common.h

@@ -18,6 +18,7 @@ unsigned int chrysler_checksum(unsigned int address, uint64_t d, int l);
 void init_crc_lookup_tables();
 unsigned int volkswagen_crc(unsigned int address, uint64_t d, int l);
 unsigned int pedal_checksum(uint64_t d, int l);
+unsigned int ocelot_checksum(uint64_t d, int l);
 uint64_t read_u64_be(const uint8_t* v);
 uint64_t read_u64_le(const uint8_t* v);
 

can/common_dbc.h

@@ -40,6 +40,8 @@ enum SignalType {
   VOLKSWAGEN_COUNTER,
   SUBARU_CHECKSUM,
   CHRYSLER_CHECKSUM,
+  OCELOT_CHECKSUM,
+  OCELOT_COUNTER,
 };
 
 struct Signal {

can/dbc_template.cc

@@ -37,6 +37,10 @@ const Signal sigs_{{address}}[] = {
       .type = SignalType::PEDAL_CHECKSUM,
       {% elif address in [512, 513] and sig.name == "COUNTER_PEDAL" %}
       .type = SignalType::PEDAL_COUNTER,
+      {% if checksum_type == "ocelot" and sig.name == "CHECKSUM" %}
+      .type = SignalType::OCELOT_CHECKSUM,
+      {% elif checksum_type == "ocelot" and sig.name == "COUNTER" %}
+      .type = SignalType::OCELOT_COUNTER,
       {% else %}
       .type = SignalType::DEFAULT,
       {% endif %}

can/packer.cc

@@ -77,7 +77,7 @@ uint64_t CANPacker::pack(uint32_t address, const std::vector<SignalPackValue> &s
     }
     auto sig = sig_it->second;
 
-    if ((sig.type != SignalType::HONDA_COUNTER) && (sig.type != SignalType::VOLKSWAGEN_COUNTER)) {
+    if ((sig.type != SignalType::HONDA_COUNTER) && (sig.type != SignalType::VOLKSWAGEN_COUNTER) && (sig.type != SignalType::OCELOT_COUNTER)) {
       WARN("COUNTER signal type not valid\n");
     }
 
@@ -105,7 +105,10 @@ uint64_t CANPacker::pack(uint32_t address, const std::vector<SignalPackValue> &s
     } else if (sig.type == SignalType::CHRYSLER_CHECKSUM) {
       unsigned int chksm = chrysler_checksum(address, ReverseBytes(ret), message_lookup[address].size);
       ret = set_value(ret, sig, chksm);
-    } else {
+    } else if (sig.type == SignalType::OCELOT_CHECKSUM) {
+      unsigned int chksm = chrysler_checksum(ret, message_lookup[address].size);
+      ret = set_value(ret, sig, chksm);
+    else {
       //WARN("CHECKSUM signal type not valid\n");
     }
   }

can/parser.cc

@@ -76,6 +76,15 @@ bool MessageState::parse(uint64_t sec, uint16_t ts_, uint8_t * dat) {
       if (!update_counter_generic(tmp, sig.b2)) {
         return false;
       }
+    } else if (sig.type == SignalType::OCELOT_CHECKSUM) {
+      if (ocelot_checksum(dat_be, size) != tmp) {
+        INFO("0x%X OCELOT CHECKSUM FAIL\n", address);
+        return false;
+      }
+    } else if (sig.type == SignalType::OCELOT_COUNTER) {
+      if (!update_counter_generic(tmp, sig.b2)) {
+        return false;
+      }
     }
 
     vals[i] = tmp * sig.factor + sig.offset;

can/process_dbc.py

@@ -61,6 +61,13 @@ def process(in_fn, out_fn):
     checksum_start_bit = 7
     counter_start_bit = None
     little_endian = False
+elif can_dbc.name.startswith(("ocelot_")):
+    checksum_type = "ocelot"
+    checksum_size = 8
+    counter_size = 4
+    checksum_start_bit = 0
+    counter_start_bit = 4
+    little_endian = True
   else:
     checksum_type = None
     checksum_size = None

ocelot_can.dbc

@@ -59,21 +59,21 @@ BO_ 512 GAS_COMMAND: 8 EON
  SG_ GAS_COMMAND : 7|16@0+ (0.159375,-75.555) [0|1] ""  PED
  SG_ GAS_COMMAND2 : 23|16@0+ (0.159375,-151.111) [0|1] ""  PED
  SG_ ENABLE : 39|1@0+ (1,0) [0|1] ""  PED
- SG_ COUNTER_PEDAL : 35|4@0+ (1,0) [0|15] ""  PED
- SG_ CHECKSUM_PEDAL : 47|8@0+ (1,0) [0|255] ""  PED
+ SG_ COUNTER : 32|4@1+ (1,0) [0|15] ""  PED
+ SG_ CHECKSUM : 40|8@1+ (1,0) [0|255] ""  PED
 
 BO_ 513 GAS_SENSOR: 8 PED
  SG_ PED_GAS : 7|16@0+ (0.159375,-75.555) [0|1] ""  EON
  SG_ PED_GAS2 : 23|16@0+ (0.159375,-151.111) [0|1] ""  EON
  SG_ STATE : 39|4@0+ (1,0) [0|15] ""  EON
- SG_ COUNTER_PEDAL : 35|4@0+ (1,0) [0|15] ""  EON
- SG_ CHECKSUM_PEDAL : 47|8@0+ (1,0) [0|255] ""  EON
+ SG_ COUNTER : 32|4@1+ (1,0) [0|15] ""  EON
+ SG_ CHECKSUM : 40|8@1+ (1,0) [0|255] ""  EON
 
 BO_ 870 CURRENT_STATE: 4 EON
  SG_ ENABLED : 0|1@0+ (1,0) [0|0] ""  HIM
  SG_ SET_SPEED : 15|8@0+ (1,0) [0|255] "mph"  HIM
  SG_ CURRENT_SPEED : 23|8@0+ (1,0) [0|255] "kph" IBST
- SG_ CHECKSUM_CTRLS : 31|8@0+ (1,0) [0|255] ""  HIM
+ SG_ CHECKSUM : 24|8@1+ (1,0) [0|255] ""  HIM
 
 BO_ 869 HIM_CTRLS: 3 HIM
  SG_ SPEEDDN_BTN : 3|1@0+ (1,0) [0|0] ""  EON
@@ -81,7 +81,7 @@ BO_ 869 HIM_CTRLS: 3 HIM
  SG_ CANCEL_BTN : 1|1@0+ (1,0) [0|0] ""  EON
  SG_ SET_BTN : 0|1@0+ (1,0) [0|0] ""  EON
  SG_ STATE : 11|4@0+ (1,0) [0|15] ""  EON
- SG_ CHECKSUM_CTRLS : 23|8@0+ (1,0) [0|255] ""  EON
+ SG_ CHECKSUM : 16|8@1+ (1,0) [0|255] ""  EON