Add PIC32MZ EF bare-metal wolfIP port: clocks, UART2, wolfCrypt RNG, LAN8740 PHY

Author: dgarske

src/port/pic32mz/.gitignore

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+# Build artifacts
+*.o
+app.elf
+app.hex
+app.map
+# MDB / IPE transient files
+mdb_flash.cmd
+MPLABXLog.*
+log.*

src/port/pic32mz/Makefile

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+# wolfIP PIC32MZ EF port - build with Microchip XC32
+#
+# Copyright (C) 2026 wolfSSL Inc.  Part of the wolfIP TCP/IP stack (GPLv3).
+#
+# Phase 0: clocks + UART2 console + heartbeat.
+# Phase 1: wolfCrypt PIC32MZ hardware TRNG self-test.
+# Phase 2: MDIO + LAN8740 PHY link bring-up.
+# (Full Ethernet RX/TX driver + wolfIP core are added in later phases.)
+#
+# Usage:
+#   make                       # build app.hex
+#   make flash                 # program over the on-board debugger (v6.20 IPE)
+#   make clean
+# Overridable:
+#   XC32_BIN=   XC32 bin dir   (default /opt/microchip/xc32/v5.10/bin)
+#   DFP=        device family pack version dir
+#   DEVICE=     32MZ2048EFM144
+#   WOLFSSL_ROOT= path to wolfssl checkout (used from Phase 1 on)
+#   MDB=        MPLAB X MDB CLI (default v6.20; v6.30 dropped the EF SK debugger)
+
+XC32_BIN ?= /opt/microchip/xc32/v5.10/bin
+DFP      ?= /opt/microchip/mplabx/v6.30/packs/Microchip/PIC32MZ-EF_DFP/1.5.173
+DEVICE   ?= 32MZ2048EFM144
+
+CC      := $(XC32_BIN)/xc32-gcc
+BIN2HEX := $(XC32_BIN)/xc32-bin2hex
+SIZE    := $(XC32_BIN)/xc32-size
+
+# Flashing via MDB (Microchip DeBugger CLI). The headless ipecmd cannot resolve
+# device packs ("Unable to locate DFP"), but MDB launches the full platform and
+# resolves them like the IDE/IPE GUI does. Default tool is an MPLAB ICD 5 on the
+# ICSP header; the EF Starter Kit's flaky on-board debugger (MDB tool type "sk",
+# only in v6.20) proved unreliable over USB, so an external debugger is preferred.
+MDB        ?= /opt/microchip/mplabx/v6.30/mplab_platform/bin/mdb.sh
+MDB_DEVICE ?= PIC32MZ2048EFM144
+MDB_TOOL   ?= icd5
+
+ROOT         := ../../..
+# Default to a wolfssl checkout sitting beside the wolfip repo.
+WOLFSSL_ROOT ?= $(ROOT)/../wolfssl
+
+# -O1 is available in the free XC32 edition (-O2/-Os/-O3 need a PRO license).
+CFLAGS := -mprocessor=$(DEVICE) -mdfp="$(DFP)"
+CFLAGS += -O1 -g -Wall -Wextra -ffunction-sections -fdata-sections
+CFLAGS += -I. -I$(ROOT) -I$(ROOT)/src
+CFLAGS += -DWOLFSSL_USER_SETTINGS -I$(WOLFSSL_ROOT)
+CFLAGS += $(EXTRA_CFLAGS)
+
+# Heap for the Hash-DRBG (wc_InitRng allocates the DRBG state).
+LDFLAGS := -mprocessor=$(DEVICE) -mdfp="$(DFP)"
+LDFLAGS += -Wl,--defsym,_min_heap_size=0x8000
+LDFLAGS += -Wl,--gc-sections -Wl,-Map=app.map,--cref
+
+# Port + application sources (strict warnings)
+APP_SRCS := device_config.c clock_init.c uart_console.c timebase.c \
+            wolf_compat.c rng_selftest.c pic32mz_eth.c phy_lan8740.c main.c
+APP_OBJS := $(patsubst %.c,%.o,$(APP_SRCS))
+
+# wolfcrypt sources for the RNG self-test (compiled with relaxed warnings).
+# Pulled directly from the sibling wolfssl checkout, no copy.
+WC_SRC  := $(WOLFSSL_ROOT)/wolfcrypt/src
+WC_NAMES := random sha256 hash wc_port logging memory error
+WC_OBJS := $(addsuffix .o,$(addprefix wc_,$(WC_NAMES)))
+CFLAGS_WC := -mprocessor=$(DEVICE) -mdfp="$(DFP)" -O1 -g \
+             -ffunction-sections -fdata-sections \
+             -DWOLFSSL_USER_SETTINGS -I. -I$(WOLFSSL_ROOT)
+
+# wolfIP core stack (relaxed warnings; does not need wolfssl).
+CFLAGS_CORE := -mprocessor=$(DEVICE) -mdfp="$(DFP)" -O1 -g \
+               -ffunction-sections -fdata-sections -I. -I$(ROOT) -I$(ROOT)/src
+
+ALL_OBJS := $(APP_OBJS) wolfip.o $(WC_OBJS)
+
+all: app.hex
+	@echo "Built PIC32MZ wolfIP port"
+	@$(SIZE) app.elf
+
+app.elf: $(ALL_OBJS)
+	$(CC) $(CFLAGS) $(ALL_OBJS) $(LDFLAGS) -o $@
+
+app.hex: app.elf
+	$(BIN2HEX) $<
+
+%.o: %.c
+	$(CC) $(CFLAGS) -c $< -o $@
+
+wc_%.o: $(WC_SRC)/%.c
+	$(CC) $(CFLAGS_WC) -c $< -o $@
+
+wolfip.o: $(ROOT)/src/wolfip.c
+	$(CC) $(CFLAGS_CORE) -c $< -o $@
+
+# Program the hex over an MPLAB ICD 5 (on the ICSP/debug header) via MDB. Close
+# the MPLAB X IPE/IDE GUI first so it isn't holding the tool. Command script:
+#   set programoptions.eraseb4program true  -> full chip erase before program
+#   hwtool icd5 -p                          -> connect the ICD 5 for programming
+#   program <app.hex> / Reset               -> program, then release from reset
+# The trailing "Reset" is required: -p alone leaves the target held in reset.
+# See the mplab-icd5 skill for connection/wiring troubleshooting.
+flash: app.hex
+	@printf 'device %s\nset programoptions.eraseb4program true\nhwtool %s -p\nprogram %s\nReset\nquit\n' \
+	    "$(MDB_DEVICE)" "$(MDB_TOOL)" "$(CURDIR)/app.hex" > mdb_flash.cmd
+	cd $(dir $(MDB)) && sh ./mdb.sh $(CURDIR)/mdb_flash.cmd
+
+clean:
+	rm -f *.o app.elf app.hex app.map mdb_flash.cmd MPLABXLog.* log.*
+
+.PHONY: all clean flash

src/port/pic32mz/README.md

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+# wolfIP PIC32MZ EF Port
+
+Bare-metal [wolfIP](../../../README.md) port for the **Microchip PIC32MZ EF**
+(PIC32MZ2048EFM144, MIPS32 M-class) with a **LAN8740** PHY over RMII. Built
+with the Microchip XC32 toolchain; no MPLAB X project or Harmony framework
+required. Also exercises wolfCrypt's built-in hardware TRNG
+(`WOLFSSL_PIC32MZ_RNG`).
+
+## Hardware
+
+- **MCU:** PIC32MZ2048EFM144 (200 MHz, 2 MB flash, 512 KB RAM), EF Starter Kit.
+- **PHY:** LAN8740 daughter board over RMII (PHY drives the 50 MHz reference clock).
+- **Console:** UART2, `U2TX` on RPB14 / `U2RX` on RPG6, 115200 8N1.
+- **Programmer:** MPLAB ICD 5 on the ICSP/debug header (see the mplab-icd5 skill).
+
+## Layout
+
+| File | Purpose |
+|------|---------|
+| `device_config.c` | DEVCFG config words: 200 MHz PLL (POSC EC 24 MHz), RMII, watchdog off. |
+| `clock_init.c/.h` | Flash wait-states + prefetch. Reusable early bring-up (wolfBoot). |
+| `cache.h` | MIPS KSEG0/KSEG1 + virtual/physical helpers for DMA memory. |
+| `uart_console.c/.h` | UART2 console + XC32 `_mon_putc` `printf` retarget. |
+| `timebase.c/.h` | 64-bit `millis()` from the CP0 core timer. |
+| `pic32mz_eth.c/.h` | EMAC + RMII + MDIO bring-up, DMA descriptor rings, `poll`/`send`. |
+| `phy_lan8740.c/.h` | MAC-agnostic clause-22 LAN8740 driver (scan, autoneg, link). |
+| `rng_selftest.c/.h` | wolfCrypt hardware-TRNG self-test. |
+| `user_settings.h` | wolfCrypt configuration (`WOLFSSL_MICROCHIP_PIC32MZ`). |
+| `config.h` | wolfIP profile (MTU, socket counts, DHCP). |
+| `main.c` | TRNG self-test, DHCP, and a TCP echo / throughput server. |
+
+## Build
+
+Requires XC32 (>= v5.10) and the PIC32MZ-EF DFP, plus a wolfssl checkout beside
+the wolfip repo (override with `WOLFSSL_ROOT=`).
+
+```sh
+make                     # -> app.hex
+make SPEED_TEST=1 EXTRA_CFLAGS=-DSPEED_TEST   # throughput server on port 9
+make flash               # program over MPLAB ICD 5 (MDB)
+make clean
+```
+
+Overridable: `XC32_BIN`, `DFP`, `DEVICE`, `WOLFSSL_ROOT`, `MDB`, `MDB_TOOL`.
+
+## Test
+
+Console at 115200 8N1. On boot the firmware prints the banner, the RNG
+self-test result, the resolved PHY link, and (once bound) the DHCP address:
+
+```
+=== wolfIP PIC32MZ EF port ===
+[RNG] self-test: PASS
+Ethernet init (LAN8740 over RMII)...
+DHCP bound: 10.0.4.x
+TCP service listening on port 7
+```
+
+Then, from a host on the same network:
+
+```sh
+ping <ip>
+echo hello | nc <ip> 7                          # echo (default build)
+dd if=/dev/zero bs=1460 count=700 | nc <ip> 9    # RX throughput (SPEED_TEST build)
+nc <ip> 9 </dev/null | pv >/dev/null             # TX throughput (SPEED_TEST build)
+```
+
+## Notes
+
+- DMA descriptors/buffers use XC32 `__attribute__((coherent))` (uncached), so
+  no cache maintenance is needed; the EMAC is given physical addresses.
+- The Ethernet module needs PBCLK5 enabled and `PMD6.ETHMD` cleared before any
+  EMAC register access — `pic32mz_emac_mii_init()` does this first.
+- Build with `EXTRA_CFLAGS=-DPIC32_ETH_TRACE` to trace the EMAC bring-up.

src/port/pic32mz/board.h

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+/* board.h
+ *
+ * Board constants for the PIC32MZ EF Starter Kit (DM320007) + LAN8740 PHY DB.
+ *
+ * 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 PIC32MZ_BOARD_H
+#define PIC32MZ_BOARD_H
+
+/* Clock tree (set by DEVCFG config words at reset; see device_config.c) */
+#define SYS_CLK_FREQ    200000000ul     /* SYSCLK from SPLL */
+#define PBCLK2_FREQ     100000000ul     /* peripheral bus 2 (UART) = SYSCLK/2 */
+#define PBCLK5_FREQ     100000000ul     /* peripheral bus 5 (EMAC) = SYSCLK/2 */
+
+/* Console UART: U2TX on RPB14, U2RX on RPG6 (external MCP2221 USB-UART) */
+#define CONSOLE_BAUD    115200u
+
+/* On-board LEDs LED1/LED2/LED3 on RH0/RH1/RH2 (active high) */
+#define LED_MASK        0x0007u
+#define LED_HEARTBEAT   0x0001u         /* LED1 = RH0 */
+
+#endif /* PIC32MZ_BOARD_H */

src/port/pic32mz/cache.h

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+/* cache.h
+ *
+ * MIPS KSEG segment helpers for DMA-coherent access on PIC32MZ.
+ *
+ * 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 PIC32MZ_CACHE_H
+#define PIC32MZ_CACHE_H
+
+#include <stdint.h>
+
+/* The PIC32MZ Ethernet controller (EMAC) is not cache-coherent and programs
+ * its descriptor base/buffer pointers with PHYSICAL addresses. The simplest
+ * coherent scheme on MIPS is to access all descriptor rings and DMA buffers
+ * through KSEG1 (uncached) virtual aliases and hand the EMAC the physical
+ * address. This avoids per-operation cache clean/invalidate entirely.
+ *
+ * Equivalent to XC32 <sys/kmem.h> KVA0_TO_KVA1 / KVA_TO_PA / PA_TO_KVA1, but
+ * kept self-contained so the early bare-metal layer can be lifted into
+ * wolfBoot without pulling in the XC32 system headers.
+ */
+
+/* Cached KSEG0 virtual address -> uncached KSEG1 virtual address */
+#define PIC32_KVA0_TO_KVA1(v)   (((uint32_t)(v)) | 0x20000000u)
+
+/* Any KSEG0/KSEG1 virtual address -> physical address (for the EMAC) */
+#define PIC32_KVA_TO_PA(v)      (((uint32_t)(v)) & 0x1FFFFFFFu)
+
+/* Physical address -> uncached KSEG1 virtual address */
+#define PIC32_PA_TO_KVA1(pa)    (((uint32_t)(pa)) | 0xA0000000u)
+
+/* Pointer helper: uncached view of a normally-allocated object */
+#define PIC32_UNCACHED(p)       ((void *)PIC32_KVA0_TO_KVA1(p))
+
+#endif /* PIC32MZ_CACHE_H */

src/port/pic32mz/clock_init.c

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+/* clock_init.c
+ *
+ * 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
+ */
+#include <xc.h>
+#include "clock_init.h"
+
+void clock_init(void)
+{
+    /* Flash wait-states + prefetch for 200 MHz SYSCLK.
+     * PFMWS = 2 wait-states is required above ~134 MHz on PIC32MZ EF.
+     * PREFEN = 3 enables predictive prefetch for cacheable and
+     * non-cacheable regions. PRECON is not lock-protected. */
+    PRECONbits.PFMWS  = 2;
+    PRECONbits.PREFEN = 3;
+
+    /* Peripheral buses PBCLK2 (UART) and PBCLK5 (EMAC) remain at their
+     * reset default of SYSCLK/2 = 100 MHz, which is what this port targets.
+     * The L1 cache and KSEG0 coherency are enabled by the XC32 reset
+     * startup code, so nothing is done here for v1. */
+}

src/port/pic32mz/clock_init.h

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+/* clock_init.h
+ *
+ * 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 PIC32MZ_CLOCK_INIT_H
+#define PIC32MZ_CLOCK_INIT_H
+
+/* Configure flash wait-states / prefetch for 200 MHz operation.
+ * The PLL itself is brought up at reset from the DEVCFG config words
+ * (FNOSC=SPLL), so by the time main() runs SYSCLK is already 200 MHz.
+ * Bare-metal reusable (intended to be lifted into a future wolfBoot port). */
+void clock_init(void);
+
+#endif /* PIC32MZ_CLOCK_INIT_H */