From 7af336244c272066d609efd8586c47467a74c609 Mon Sep 17 00:00:00 2001
From: Jason Wen <haibin.wen3@gmail.com>
Date: Tue, 3 Oct 2023 00:32:13 -0400
Subject: [PATCH] Hyundai CAN-FD: Move CRC compute function to common Hyundai
 safety (#1634)

* HKG CAN-FD: Move CRC lookup function to common Hyundai safety

* cleanup

* declare in common

* Subaru: gen2 long safety (#1594)

gen2 long safety

* VW MQB: Check steer req bit (#1631)

vq mqb

* cleanup

* more cleanup

---------

Co-authored-by: Justin Newberry <justin@comma.ai>
Co-authored-by: Adeeb Shihadeh <adeebshihadeh@gmail.com>
---
 board/safety/safety_hyundai_canfd.h  | 34 +---------------------------
 board/safety/safety_hyundai_common.h | 31 +++++++++++++++++++++++++
 2 files changed, 32 insertions(+), 33 deletions(-)

diff --git a/board/safety/safety_hyundai_canfd.h b/board/safety/safety_hyundai_canfd.h
index 4e172b3470..f0af9060eb 100644
--- a/board/safety/safety_hyundai_canfd.h
+++ b/board/safety/safety_hyundai_canfd.h
@@ -128,9 +128,6 @@ AddrCheckStruct hyundai_canfd_hda2_long_addr_checks[] = {
 addr_checks hyundai_canfd_rx_checks = SET_ADDR_CHECKS(hyundai_canfd_addr_checks);
 
 
-uint16_t hyundai_canfd_crc_lut[256];
-
-
 const int HYUNDAI_PARAM_CANFD_ALT_BUTTONS = 32;
 const int HYUNDAI_PARAM_CANFD_HDA2_ALT_STEERING = 128;
 bool hyundai_canfd_alt_buttons = false;
@@ -156,39 +153,10 @@ static uint32_t hyundai_canfd_get_checksum(CANPacket_t *to_push) {
   return chksum;
 }
 
-static uint32_t hyundai_canfd_compute_checksum(CANPacket_t *to_push) {
-  int len = GET_LEN(to_push);
-  uint32_t address = GET_ADDR(to_push);
-
-  uint16_t crc = 0;
-
-  for (int i = 2; i < len; i++) {
-    crc = (crc << 8U) ^ hyundai_canfd_crc_lut[(crc >> 8U) ^ GET_BYTE(to_push, i)];
-  }
-
-  // Add address to crc
-  crc = (crc << 8U) ^ hyundai_canfd_crc_lut[(crc >> 8U) ^ ((address >> 0U) & 0xFFU)];
-  crc = (crc << 8U) ^ hyundai_canfd_crc_lut[(crc >> 8U) ^ ((address >> 8U) & 0xFFU)];
-
-  if (len == 8) {
-    crc ^= 0x5f29U;
-  } else if (len == 16) {
-    crc ^= 0x041dU;
-  } else if (len == 24) {
-    crc ^= 0x819dU;
-  } else if (len == 32) {
-    crc ^= 0x9f5bU;
-  } else {
-
-  }
-
-  return crc;
-}
-
 static int hyundai_canfd_rx_hook(CANPacket_t *to_push) {
 
   bool valid = addr_safety_check(to_push, &hyundai_canfd_rx_checks,
-                                 hyundai_canfd_get_checksum, hyundai_canfd_compute_checksum, hyundai_canfd_get_counter, NULL);
+                                 hyundai_canfd_get_checksum, hyundai_common_canfd_compute_checksum, hyundai_canfd_get_counter, NULL);
 
   int bus = GET_BUS(to_push);
   int addr = GET_ADDR(to_push);
diff --git a/board/safety/safety_hyundai_common.h b/board/safety/safety_hyundai_common.h
index 34974a4a64..8fec9b06cd 100644
--- a/board/safety/safety_hyundai_common.h
+++ b/board/safety/safety_hyundai_common.h
@@ -27,6 +27,8 @@ bool hyundai_canfd_hda2 = false;
 bool hyundai_alt_limits = false;
 uint8_t hyundai_last_button_interaction;  // button messages since the user pressed an enable button
 
+uint16_t hyundai_canfd_crc_lut[256];
+
 void hyundai_common_init(uint16_t param) {
   hyundai_ev_gas_signal = GET_FLAG(param, HYUNDAI_PARAM_EV_GAS);
   hyundai_hybrid_gas_signal = !hyundai_ev_gas_signal && GET_FLAG(param, HYUNDAI_PARAM_HYBRID_GAS);
@@ -85,4 +87,33 @@ void hyundai_common_cruise_buttons_check(const int cruise_button, const int main
   }
 }
 
+uint32_t hyundai_common_canfd_compute_checksum(CANPacket_t *to_push) {
+  int len = GET_LEN(to_push);
+  uint32_t address = GET_ADDR(to_push);
+
+  uint16_t crc = 0;
+
+  for (int i = 2; i < len; i++) {
+    crc = (crc << 8U) ^ hyundai_canfd_crc_lut[(crc >> 8U) ^ GET_BYTE(to_push, i)];
+  }
+
+  // Add address to crc
+  crc = (crc << 8U) ^ hyundai_canfd_crc_lut[(crc >> 8U) ^ ((address >> 0U) & 0xFFU)];
+  crc = (crc << 8U) ^ hyundai_canfd_crc_lut[(crc >> 8U) ^ ((address >> 8U) & 0xFFU)];
+
+  if (len == 8) {
+    crc ^= 0x5f29U;
+  } else if (len == 16) {
+    crc ^= 0x041dU;
+  } else if (len == 24) {
+    crc ^= 0x819dU;
+  } else if (len == 32) {
+    crc ^= 0x9f5bU;
+  } else {
+
+  }
+
+  return crc;
+}
+
 #endif