From 5381f6378f2f36f2980a1bab588e8b37b570cc88 Mon Sep 17 00:00:00 2001
From: Henrik Davidsen <henrik.davidsen@space-inventor.com>
Date: Tue, 24 Feb 2026 07:02:12 +0100
Subject: [PATCH] Use atomic_int for cfp_packet_counter in CAN and packet_id in
 ETH TX

This is needed as ++ is not atomic on an integer
---
 include/csp/interfaces/csp_if_can.h | 4 +++-
 src/interfaces/csp_if_can.c         | 6 +++---
 src/interfaces/csp_if_eth.c         | 3 ++-
 3 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/include/csp/interfaces/csp_if_can.h b/include/csp/interfaces/csp_if_can.h
index 5d04b17e7..106515539 100644
--- a/include/csp/interfaces/csp_if_can.h
+++ b/include/csp/interfaces/csp_if_can.h
@@ -60,6 +60,8 @@
 #pragma once
 
 #include <csp/csp_interface.h>
+#include <stdint.h>
+#include <stdatomic.h>
 
 #ifdef __cplusplus
 extern "C" {
@@ -190,7 +192,7 @@ typedef int (*csp_can_driver_tx_t)(void * driver_data, uint32_t id, const uint8_
  * Interface data (state information).
  */
 typedef struct {
-	uint32_t cfp_packet_counter; /**< CFP Identification number - same number on all fragments from same CSP packet. */
+	atomic_int cfp_packet_counter; /**< CFP Identification number - same number on all fragments from same CSP packet. */
 	csp_can_driver_tx_t tx_func; /**< Tx function */
 	csp_packet_t * pbufs; /**< PBUF queue */
 } csp_can_interface_data_t;
diff --git a/src/interfaces/csp_if_can.c b/src/interfaces/csp_if_can.c
index f50897e60..6d1038e09 100644
--- a/src/interfaces/csp_if_can.c
+++ b/src/interfaces/csp_if_can.c
@@ -166,8 +166,8 @@ static int csp_can1_tx(csp_iface_t * iface, uint16_t via, csp_packet_t * packet,
 
 	csp_can_interface_data_t * ifdata = iface->interface_data;
 
-	/* Get an unique CFP id - this should be locked to prevent access from multiple tasks */
-	const uint32_t ident = ifdata->cfp_packet_counter++;
+	/* Get an unique CFP id */
+	const uint32_t ident = ifdata->cfp_packet_counter++; // Atomic operation as cfp_packet_counter is of type atomic_int
 
 	/* Figure out destination node based on routing entry */
 	const uint8_t dest = (via != CSP_NO_VIA_ADDRESS) ? via : packet->id.dst;
@@ -370,7 +370,7 @@ static int csp_can2_tx(csp_iface_t * iface, uint16_t via, csp_packet_t * packet,
 	csp_can_interface_data_t * ifdata = iface->interface_data;
 
 	/* Setup counters */
-	int sender_count = ifdata->cfp_packet_counter++;
+	int sender_count = ifdata->cfp_packet_counter++; // Atomic operation as cfp_packet_counter is of type atomic_int
 	int tx_count = 0;
 
 	uint32_t can_id = 0;
diff --git a/src/interfaces/csp_if_eth.c b/src/interfaces/csp_if_eth.c
index d5382811c..afabdb6be 100644
--- a/src/interfaces/csp_if_eth.c
+++ b/src/interfaces/csp_if_eth.c
@@ -9,6 +9,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
+#include <stdatomic.h>
 
 #include <csp/csp.h>
 #include <csp/csp_id.h>
@@ -254,7 +255,7 @@ int csp_eth_tx(csp_iface_t * iface, uint16_t via, csp_packet_t * packet, int fro
 
     csp_id_prepend(packet);
 
-    static uint16_t packet_id = 0;
+    static atomic_int packet_id = 0;
     packet_id++;
     uint16_t offset = 0;