Address fenrir, copilot, and internal review

  - Makefile: Add cppcheck comparePointers suppressions for lpc54s018 startup.c/syscalls.c
  - main.c: Fix non-atomic 64-bit tick_ms reads with get_tick_ms() (disable/enable interrupts)
  - startup.c: Restore __libc_init_array() call (matches other ports)
  - lpc_enet.c: Add RX_BUF_SIZE bounds check in eth_poll to prevent buffer over-read
  - fix_checksum.py: Auto-detect vector table offset (0x0 for RAM build, 0x200 for flash)
  - target_ram.ld: Clarify SRAM2 is 32KB on J4M package
  - flash.sh: Add flash helper script (matches N6 port's flash.sh)

Author: aidangarske

.github/workflows/codespell.yml

@@ -23,4 +23,4 @@ jobs:
         uses: codespell-project/actions-codespell@v2
         with:
           skip: .git,./IDE,*.der,*.pem
-          ignore_words_list: inh,inout,keypair,nd,parm,rcv,ser,tha,HSI,TE,UE,Synopsys,synopsys
+          ignore_words_list: inh,inout,keypair,nd,parm,rcv,ser,tha,HSI,TE,UE,Synopsys,synopsys,FRO

Makefile

@@ -123,6 +123,8 @@ CPPCHECK_FLAGS=--enable=warning,performance,portability,missingInclude \
 			   --suppress=comparePointers:src/port/stm32n6/syscalls.c \
 			   --suppress=comparePointers:src/port/va416xx/startup.c \
 			   --suppress=comparePointers:src/port/va416xx/syscalls.c \
+			   --suppress=comparePointers:src/port/lpc54s018/startup.c \
+			   --suppress=comparePointers:src/port/lpc54s018/syscalls.c \
 			   --disable=style \
 			   --std=c99 --language=c \
 			   --platform=unix64 \

src/port/lpc54s018/fix_checksum.py

@@ -2,49 +2,52 @@
 # fix_checksum.py - compute LPC vector table checksum
 #
 # The LPC54S018 boot ROM requires that vector table entries 0-7 sum to zero.
-# The vector table starts at offset 0x200 in the binary (after the 512-byte
-# SPIFI configuration block).
-#
-# This script patches entry[7] so that sum(entries[0:8]) == 0 (mod 2^32).
+# Auto-detects whether vector table is at offset 0 (RAM build) or 0x200
+# (SPIFI flash build with 512-byte config block).
 
 import struct
 import sys
 
-SPIFI_CONFIG_SIZE = 0x200  # 512-byte SPIFI config block before vector table
+def find_vector_offset(data):
+    """Detect vector table offset by checking for valid SP."""
+    for off in (0, 0x200):
+        if off + 32 > len(data):
+            continue
+        sp = struct.unpack_from('<I', data, off)[0]
+        if 0x20000000 <= sp <= 0x20030000:
+            return off
+    return 0
 
 def main():
     if len(sys.argv) != 2:
-        print(f"Usage: {sys.argv[0]} <app.bin>")
+        print("Usage: %s <app.bin>" % sys.argv[0])
         sys.exit(1)
 
     fname = sys.argv[1]
     with open(fname, 'r+b') as f:
-        f.seek(SPIFI_CONFIG_SIZE)
-        data = f.read(32)
-        if len(data) < 32:
-            print(f"Error: file too small (need at least {SPIFI_CONFIG_SIZE + 32} bytes)")
+        data = f.read()
+        off = find_vector_offset(data)
+
+        if off + 32 > len(data):
+            print("Error: file too small")
             sys.exit(1)
 
-        vecs = list(struct.unpack('<8I', data))
-        # Compute checksum: entry[7] = -(sum of entries 0-6) mod 2^32
+        vecs = list(struct.unpack_from('<8I', data, off))
         partial_sum = sum(vecs[:7]) & 0xFFFFFFFF
         cksum = (0x100000000 - partial_sum) & 0xFFFFFFFF
-        vecs[7] = cksum
 
-        # Write back
-        f.seek(SPIFI_CONFIG_SIZE + 7 * 4)
+        f.seek(off + 7 * 4)
         f.write(struct.pack('<I', cksum))
 
-    # Verify
     with open(fname, 'rb') as f:
-        f.seek(SPIFI_CONFIG_SIZE)
+        f.seek(off)
         vecs = struct.unpack('<8I', f.read(32))
         total = sum(vecs) & 0xFFFFFFFF
         if total != 0:
-            print(f"ERROR: checksum verification failed (sum=0x{total:08X})")
+            print("ERROR: checksum verification failed (sum=0x%08X)" % total)
             sys.exit(1)
 
-    print(f"Vector checksum patched: entry[7]=0x{cksum:08X}")
+    print("Vector checksum patched: offset=0x%X entry[7]=0x%08X" % (off, cksum))
 
 if __name__ == '__main__':
     main()

src/port/lpc54s018/flash.sh

@@ -0,0 +1,28 @@
+#!/bin/bash
+# Flash wolfIP to LPC54S018M-EVK SRAM via pyocd (on-board Link2 CMSIS-DAP)
+set -e
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+ELF="${SCRIPT_DIR}/app.elf"
+BIN="${SCRIPT_DIR}/app.bin"
+
+[ -f "$ELF" ] || { echo "app.elf not found. Run 'make' first."; exit 1; }
+
+# Extract initial SP (word 0) and entry point (word 1) from binary
+INIT_SP=$(od -A n -t x4 -N 4 "$BIN" | awk '{print "0x"$1}')
+ENTRY=$(od -A n -j 4 -t x4 -N 4 "$BIN" | awk '{print "0x"$1}')
+
+echo "Loading app.elf to SRAM via pyocd"
+echo "  SP: ${INIT_SP}, Entry: ${ENTRY}"
+
+pyocd commander -t lpc54608 -c "
+    halt;
+    load ${ELF};
+    write32 0xE000ED08 0x20000000;
+    write32 0x40000220 0x78;
+    wreg sp ${INIT_SP};
+    wreg pc ${ENTRY};
+    go;
+    exit
+"
+
+echo "Done. Monitor UART: screen /dev/ttyACM0 115200"

src/port/lpc54s018/main.c

@@ -85,12 +85,23 @@ void SysTick_Handler(void)
     tick_ms++;
 }
 
+/* Atomic read of 64-bit tick_ms on 32-bit Cortex-M4.
+ * Briefly disables interrupts to prevent torn reads. */
+static uint64_t get_tick_ms(void)
+{
+    uint64_t val;
+    __asm volatile ("cpsid i" ::: "memory");
+    val = tick_ms;
+    __asm volatile ("cpsie i" ::: "memory");
+    return val;
+}
+
 uint32_t wolfIP_getrandom(void)
 {
     static uint32_t lfsr;
     static int seeded = 0;
     if (!seeded) {
-        lfsr = (uint32_t)tick_ms;
+        lfsr = (uint32_t)get_tick_ms();
         if (lfsr == 0U) lfsr = 0x1A2B3C4DU;
         seeded = 1;
     }
@@ -102,8 +113,8 @@ uint32_t wolfIP_getrandom(void)
 
 static void delay_ms(uint32_t ms)
 {
-    uint64_t target = tick_ms + ms;
-    while (tick_ms < target) { }
+    uint64_t target = get_tick_ms() + ms;
+    while (get_tick_ms() < target) { }
 }
 
 static void clock_init(void)
@@ -257,7 +268,7 @@ int main(void)
     /* IP configuration: DHCP or static fallback */
 #ifdef DHCP
     printf("Starting DHCP...\r\n");
-    (void)wolfIP_poll(IPStack, tick_ms);  /* Prime last_tick */
+    (void)wolfIP_poll(IPStack, get_tick_ms());  /* Prime last_tick */
     (void)dhcp_client_init(IPStack);
 #else
     {
@@ -289,13 +300,13 @@ int main(void)
     {
         uint64_t last_led_ms = 0;
 #ifdef DHCP
-        uint64_t dhcp_start_ms = tick_ms;
-        uint64_t dhcp_reinit_ms = tick_ms;
+        uint64_t dhcp_start_ms = get_tick_ms();
+        uint64_t dhcp_reinit_ms = get_tick_ms();
         int dhcp_done = 0;
 #endif
 
         for (;;) {
-            uint64_t now = tick_ms;
+            uint64_t now = get_tick_ms();
             (void)wolfIP_poll(IPStack, now);
 
 #ifdef DHCP

src/port/lpc54s018/startup.c

@@ -26,6 +26,7 @@ extern uint32_t _edata;
 extern uint32_t _sbss;
 extern uint32_t _ebss;
 
+extern void __libc_init_array(void);
 int main(void);
 
 /* Enable SRAM1/2 clocks before touching BSS or stack in those regions */
@@ -45,6 +46,7 @@ void Reset_Handler(void)
     for (dst = &_sbss; dst < &_ebss; )
         *dst++ = 0u;
 
+    __libc_init_array();
     (void)main();
     while (1) { }
 }

src/port/lpc54s018/target_ram.ld

@@ -2,7 +2,7 @@
  *
  * SRAM0: 64KB @ 0x20000000 - code, data, BSS
  * SRAM1: 64KB @ 0x20010000 - BSS overflow
- * SRAM2: 32KB @ 0x20020000 - stack (separate to avoid BSS/stack overlap)
+ * SRAM2: 32KB @ 0x20020000 - stack only (32KB on J4M package, not 64KB)
  */
 MEMORY
 {

src/port/lpc_enet/lpc_enet.c

@@ -404,6 +404,7 @@ static int eth_poll(struct wolfIP_ll_dev *dev, void *frame, uint32_t len)
     status = desc->des3;
     if ((status & (RDES3_FS | RDES3_LS)) == (RDES3_FS | RDES3_LS)) {
         frame_len = status & RDES3_PL_MASK;
+        if (frame_len > RX_BUF_SIZE) frame_len = RX_BUF_SIZE;
         if (frame_len > len) frame_len = len;
         if (frame_len > 0)
             memcpy(frame, rx_buffers[rx_idx], frame_len);