Add STM32F437/F439 wolfIP port (NUCLEO-F439ZI / STM32439I-EVAL)

src/port/stm32f4/stm32f4_eth.h

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+/* stm32f4_eth.h
+ *
+ * Shared Ethernet driver for STM32F4xx (DWC GMAC legacy v1 descriptors).
+ * Used by STM32F407/F417/F427/F437/F439/F469/F479 wolfIP ports.
+ *
+ * Copyright (C) 2026 wolfSSL Inc.
+ *
+ * This file is part of wolfIP TCP/IP stack.
+ *
+ * wolfIP is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * wolfIP is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335, USA
+ */
+#ifndef WOLFIP_STM32F4_ETH_H
+#define WOLFIP_STM32F4_ETH_H
+
+#include <stdint.h>
+#include "wolfip.h"
+
+/* Millisecond tick counter, maintained by SysTick_Handler in the port's
+ * main.c.  Reads on Cortex-M4 are non-atomic (LDRD is interruptible), so
+ * always read it through stm32f4_hal_time_ms() below to avoid tearing. */
+extern volatile uint64_t HAL_time_ms;
+
+/* Tear-free read of HAL_time_ms.  Lamport double-read: in the worst case a
+ * SysTick fires between the two halves and a/b disagree, so re-read. */
+static inline uint64_t stm32f4_hal_time_ms(void)
+{
+    uint64_t a, b;
+    do {
+        a = HAL_time_ms;
+        b = HAL_time_ms;
+    } while (a != b);
+    return b;
+}
+
+/* Initialize the STM32F4 Ethernet MAC + DMA + PHY and hook the driver into
+ * the wolfIP link-layer device.  PHY auto-negotiation is run synchronously
+ * with a 5-second timeout.  Returns 0 on success, -2 if the PHY is reachable
+ * but link did not come up (MAC/DMA still left running so a late link comes
+ * up naturally), or -1 on a fatal init error.
+ *
+ * The caller must already have configured the RCC (ETHMAC/ETHMACTX/ETHMACRX
+ * clocks), SYSCFG_PMC.MII_RMII_SEL, and the RMII GPIO pinmux before calling.
+ */
+int stm32f4_eth_init(struct wolfIP_ll_dev *ll, const uint8_t *mac);
+
+void stm32f4_eth_get_stats(uint32_t *polls, uint32_t *pkts, uint32_t *tx_pkts,
+                           uint32_t *tx_errs);
+uint32_t stm32f4_eth_get_dma_status(void);
+void stm32f4_eth_get_mac_diag(uint32_t *mac_cfg, uint32_t *mac_dbg);
+
+#endif /* WOLFIP_STM32F4_ETH_H */

src/port/stm32f439/Makefile

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+CC      ?= arm-none-eabi-gcc
+OBJCOPY ?= arm-none-eabi-objcopy
+SIZE    ?= arm-none-eabi-size
+
+ROOT := ../../..
+
+# Cortex-M4F with FPU (hardware float, single-precision).  Both NUCLEO-F439ZI
+# and STM32439I-EVAL ship STM32F437/F439 silicon with the same FPU.
+CFLAGS := -mcpu=cortex-m4 -mthumb -mfpu=fpv4-sp-d16 -mfloat-abi=hard
+CFLAGS += -Os -ffreestanding -fdata-sections -ffunction-sections
+CFLAGS += -g -ggdb -Wall -Wextra -Werror
+
+# Include paths
+CFLAGS += -I. -I$(ROOT) -I$(ROOT)/src -I$(ROOT)/src/port/stm32f4
+
+# Board selection.  Both supported boards use STM32F437/F439 silicon (same
+# DWC GMAC + same register layout) but differ in PHY addr, UART pinmux,
+# HSE source, and RMII TXD1 pin.  Set BOARD on the make command line:
+#   BOARD=nucleo_f439zi    NUCLEO-F439ZI dev board (LAN8742A, USART3, HSE 8MHz bypass)
+#   BOARD=stm32439i_eval   STM32439I-EVAL eval board (DP83848, UART4, HSE 25MHz crystal)
+BOARD ?= nucleo_f439zi
+
+ifeq ($(BOARD),nucleo_f439zi)
+  CFLAGS += -DBOARD_NUCLEO_F439ZI -DSTM32F4_ETH_PHY_ADDR=0
+else ifeq ($(BOARD),stm32439i_eval)
+  CFLAGS += -DBOARD_STM32439I_EVAL -DSTM32F4_ETH_PHY_ADDR=1
+else
+  $(error Unknown BOARD '$(BOARD)' - use nucleo_f439zi or stm32439i_eval)
+endif
+
+EXTRA_CFLAGS ?=
+CFLAGS += $(EXTRA_CFLAGS)
+
+# Relaxed warnings for wolfIP core (some unused-param noise on small builds)
+CFLAGS_EXT := $(filter-out -Werror,$(CFLAGS))
+CFLAGS_EXT += -Wno-unused-variable -Wno-unused-function -Wno-unused-parameter
+
+LDFLAGS := -nostdlib -T target.ld -Wl,-gc-sections
+
+# Application sources (strict warnings)
+APP_SRCS := startup.c ivt.c syscalls.c main.c \
+            $(ROOT)/src/port/stm32f4/stm32f4_eth.c
+APP_OBJS := startup.o ivt.o syscalls.o main.o stm32f4_eth.o
+
+# wolfIP core (relaxed warnings)
+WOLFIP_OBJ := wolfip.o
+
+ALL_OBJS := $(APP_OBJS) $(WOLFIP_OBJ)
+
+all: app.bin
+	@echo "Built STM32F439 wolfIP port (BOARD=$(BOARD))"
+	@$(SIZE) app.elf
+
+app.elf: $(ALL_OBJS) target.ld
+	$(CC) $(CFLAGS) $(ALL_OBJS) $(LDFLAGS) \
+	    -Wl,--start-group -lc -lm -lgcc -lnosys -Wl,--end-group -o $@
+
+app.bin: app.elf
+	$(OBJCOPY) -O binary $< $@
+
+# Local sources -- strict warnings
+startup.o: startup.c
+	$(CC) $(CFLAGS) -c $< -o $@
+ivt.o: ivt.c
+	$(CC) $(CFLAGS) -c $< -o $@
+syscalls.o: syscalls.c
+	$(CC) $(CFLAGS) -c $< -o $@
+main.o: main.c
+	$(CC) $(CFLAGS) -c $< -o $@
+
+# Shared F4 ETH driver (strict warnings)
+stm32f4_eth.o: $(ROOT)/src/port/stm32f4/stm32f4_eth.c
+	$(CC) $(CFLAGS) -c $< -o $@
+
+# wolfIP core (relaxed warnings)
+$(WOLFIP_OBJ): $(ROOT)/src/wolfip.c
+	$(CC) $(CFLAGS_EXT) -c $< -o $@
+
+clean:
+	rm -f *.o app.elf app.bin
+
+# Show memory usage
+size: app.elf
+	@echo "=== Memory Usage ==="
+	@$(SIZE) app.elf
+	@echo ""
+	@echo "Flash usage: $$($(SIZE) app.elf | awk 'NR==2{printf "%.2f%% (%d / %d bytes)", ($$1+$$2)*100/2097152, $$1+$$2, 2097152}')"
+	@echo "RAM usage (static): $$($(SIZE) app.elf | awk 'NR==2{printf "%.2f%% (%d / %d bytes)", ($$2+$$3)*100/196608, $$2+$$3, 196608}')"
+
+.PHONY: all clean size help
+
+help:
+	@echo "STM32F439 wolfIP Build System (supports F437/F439 silicon)"
+	@echo ""
+	@echo "Usage: make [target] [options]"
+	@echo ""
+	@echo "Targets:"
+	@echo "  all      Build app.bin (default)"
+	@echo "  clean    Remove build artifacts"
+	@echo "  size     Show memory usage statistics"
+	@echo "  help     Show this help"
+	@echo ""
+	@echo "Options:"
+	@echo "  BOARD=nucleo_f439zi        NUCLEO-F439ZI (default; LAN8742A, USART3, HSE 8MHz bypass)"
+	@echo "  BOARD=stm32439i_eval       STM32439I-EVAL (DP83848, UART4, HSE 25MHz crystal)"
+	@echo "  EXTRA_CFLAGS=-DDEBUG_ETH   Verbose ETH driver diagnostics"
+	@echo "  CC=                        C compiler (default: arm-none-eabi-gcc)"
+	@echo ""
+	@echo "Testing:"
+	@echo "  ping <ip>                  # ICMP ping"
+	@echo "  echo 'hello' | nc <ip> 7   # TCP echo"

src/port/stm32f439/README.md

@@ -0,0 +1,130 @@
+# wolfIP on STM32F437/F439
+
+Bare-metal wolfIP port for STMicro STM32F437/F439 silicon.  Supports two
+boards from one source tree, selected at compile time via `BOARD=`:
+
+| Board            | MCU          | PHY       | VCP UART               | HSE                        | RMII TXD1 |
+|------------------|--------------|-----------|------------------------|----------------------------|-----------|
+| `nucleo_f439zi`  | STM32F439ZIT | LAN8742A  | USART3 (PD8/PD9, AF7)  | 8 MHz BYPASS (ST-LINK MCO) | PB13      |
+| `stm32439i_eval` | STM32F437IIH | DP83848   | UART4 (PC10/PC11, AF8) | 25 MHz crystal             | PG14      |
+
+Brings up Ethernet (RMII), runs DHCP, and exposes a TCP echo server on
+port 7 plus ICMP ping.
+
+**Status:** `nucleo_f439zi` has been booted end-to-end on hardware (no
+cable -- clocks/UART/MAC/MDIO/PHY-ID verified; link-up + DHCP path not
+yet exercised).  `stm32439i_eval` is compile-tested only; the build
+artifact has not yet been validated on the STM32439I-EVAL hardware.
+
+## Hardware
+
+- MCU: Cortex-M4F @ 168 MHz, 2 MB flash, 256 KB RAM (192 KB main SRAM +
+  64 KB CCM; this port keeps everything in main SRAM since the GMAC DMA
+  cannot reach CCM).
+- Clock: HSE -> PLL -> SYSCLK 168 MHz, HCLK 168 MHz, PCLK1 42 MHz,
+  PCLK2 84 MHz.  PLL pre-divider differs per board (PLLM=8 for NUCLEO
+  HSE_BYPASS 8 MHz, PLLM=25 for EVAL 25 MHz crystal); the post-divider
+  chain and SYSCLK target are identical.
+- Ethernet: Synopsys DWC GMAC (legacy 16-byte descriptors, ATDS=0) in
+  RMII mode.  Driver in `src/port/stm32f4/`.
+
+## RMII pin map (shared, with the per-board TXD1 noted)
+
+| Signal           | Pin                            | AF  |
+|------------------|--------------------------------|-----|
+| ETH_RMII_REF_CLK | PA1                            | 11  |
+| ETH_MDIO         | PA2                            | 11  |
+| ETH_RMII_CRS_DV  | PA7                            | 11  |
+| ETH_MDC          | PC1                            | 11  |
+| ETH_RMII_RXD0    | PC4                            | 11  |
+| ETH_RMII_RXD1    | PC5                            | 11  |
+| ETH_RMII_TX_EN   | PG11                           | 11  |
+| ETH_RMII_TXD0    | PG13                           | 11  |
+| ETH_RMII_TXD1    | PB13 (NUCLEO) / PG14 (EVAL)    | 11  |
+
+## Build
+
+```
+make clean
+make                          # default: BOARD=nucleo_f439zi
+make BOARD=stm32439i_eval     # for the STM32439I-EVAL
+```
+
+Outputs `app.bin` (raw binary for ST-LINK) and `app.elf` (with debug
+info for GDB / addr2line).
+
+Verbose ETH bring-up diagnostics:
+
+```
+make clean
+make EXTRA_CFLAGS=-DDEBUG_ETH
+```
+
+Memory usage report:
+
+```
+make size
+```
+
+## Flash
+
+Via ST-LINK CLI:
+
+```
+st-flash write app.bin 0x08000000
+```
+
+If multiple ST-LINKs are connected, target a specific probe by serial:
+
+```
+st-flash --serial <ST-LINK-serial> --reset write app.bin 0x08000000
+```
+
+Or via STM32CubeProgrammer with the onboard ST-LINK/V2-1.
+
+## Expected UART output
+
+```
+=== wolfIP STM32F437/F439 (NUCLEO-F439ZI) ===
+Build: <date> <time>
+SYSCLK = 168000000 Hz, HCLK = 168000000 Hz, ...
+Initializing Ethernet (RMII + LAN8742A)...
+  PHY ID at addr 0: 0x0007 / 0xC131
+  PHY link: UP, AN: complete
+Starting DHCP...
+DHCP bound:
+  IP:   <ip>
+  Mask: <mask>
+  GW:   <gw>
+TCP echo server on port 7
+Ready! Test with:
+  ping <ip>
+  echo 'hello' | nc <ip> 7
+```
+
+Every 10 s the main loop prints a diagnostic line with packet counters
+and MAC/DMA register snapshots (useful when the link isn't coming up):
+
+```
+[30] rx=0 tx=3/343030 maccr=0x0000848C macdbg=0x01120000 dmasr=0x00260400
+```
+
+For the EVAL build, the banner shows `STM32439I-EVAL` and `DP83848` /
+PHY addr 1 instead.
+
+## Test
+
+From a host on the same subnet as the device:
+
+```
+ping <ip>
+echo 'hello' | nc <ip> 7
+```
+
+## Out of scope (milestone 1)
+
+- TLS / HTTPS / SSH / MQTT (the H563 port shows the wolfSSL hook-in
+  pattern; can be ported here once basic eth works).
+- wolfBoot / TFTP partition update.
+- FreeRTOS.
+- IRQ-driven RX (this port uses poll mode like the VA416xx milestone-1).

src/port/stm32f439/config.h

@@ -0,0 +1,71 @@
+/* config.h
+ *
+ * wolfIP build-time configuration for the STM32F437 port (STM32439I-EVAL).
+ *
+ * Copyright (C) 2026 wolfSSL Inc.
+ *
+ * This file is part of wolfIP TCP/IP stack.
+ *
+ * wolfIP is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * wolfIP is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335, USA
+ */
+#ifndef WOLF_CONFIG_H
+#define WOLF_CONFIG_H
+
+#ifndef CONFIG_IPFILTER
+#define CONFIG_IPFILTER         0
+#endif
+
+#define ETHERNET
+#define LINK_MTU                1536
+
+/* STM32F437IIHx has 256KB RAM (192KB main SRAM + 64KB CCM).  We have
+ * plenty of room compared to the VA416xx port.  Keep the socket count
+ * modest for milestone-1 bring-up. */
+#define MAX_TCPSOCKETS          2    /* listen + 1 client */
+#define MAX_UDPSOCKETS          1    /* DHCP */
+#define MAX_ICMPSOCKETS         1
+#define RXBUF_SIZE              LINK_MTU
+#define TXBUF_SIZE              LINK_MTU
+
+#define MAX_NEIGHBORS           4
+#define WOLFIP_ARP_PENDING_MAX  2
+
+#ifndef WOLFIP_MAX_INTERFACES
+#define WOLFIP_MAX_INTERFACES   1
+#endif
+
+#ifndef WOLFIP_ENABLE_FORWARDING
+#define WOLFIP_ENABLE_FORWARDING 0
+#endif
+
+#ifndef WOLFIP_ENABLE_LOOPBACK
+#define WOLFIP_ENABLE_LOOPBACK  0
+#endif
+
+#ifndef WOLFIP_ENABLE_DHCP
+#define WOLFIP_ENABLE_DHCP      1
+#endif
+
+/* Static IP fallback (used when DHCP is disabled or times out) */
+#define WOLFIP_IP               "192.168.12.37"
+#define WOLFIP_NETMASK          "255.255.255.0"
+#define WOLFIP_GW               "192.168.12.1"
+#define WOLFIP_STATIC_DNS_IP    "8.8.8.8"
+
+#if WOLFIP_ENABLE_DHCP
+#define DHCP
+#endif
+
+#endif /* WOLF_CONFIG_H */