PolarFire SoC M-Mode Support with DDR Initialization

This PR adds comprehensive support for running wolfBoot in M-mode (Machine mode) on the PolarFire SoC MPFS250T, including DDR controller initialization for LPDDR4 memory. This enables wolfBoot to run directly from eNVM without requiring HSS (Hart Software Services), providing a standalone boot solution.

Author: dgarske

arch.mk

@@ -581,6 +581,18 @@ endif
 ## RISCV64 (64-bit)
 ifeq ($(ARCH),RISCV64)
   CROSS_COMPILE?=riscv64-unknown-elf-
+
+  # M-mode vs S-mode configuration
+  ifeq ($(RISCV_MMODE),1)
+    # Machine Mode: Running directly from eNVM/L2 SRAM
+    # Boots from SD card after initializing DDR
+    CFLAGS+=-DWOLFBOOT_RISCV_MMODE
+    # Use M-mode specific linker script
+    LSCRIPT_IN:=hal/$(TARGET)-m.ld
+  else
+    # Supervisor Mode (default): Running under HSS with DDR available
+  endif
+
   CFLAGS+=-DMMU -DWOLFBOOT_DUALBOOT
 
   # If SD card or eMMC is enabled use update_disk loader with GPT support
@@ -607,6 +619,7 @@ ifeq ($(ARCH),RISCV64)
   # Unified RISC-V boot code (32/64-bit via __riscv_xlen)
   OBJS+=src/boot_riscv_start.o src/boot_riscv.o src/vector_riscv.o
 
+  # FDT support required
   CFLAGS+=-DWOLFBOOT_FDT
   OBJS+=src/fdt.o
 

config/examples/polarfire_mpfs250-m.config

@@ -0,0 +1,98 @@
+# PolarFire SoC MPFS250T M-Mode (Machine Mode) Configuration
+#
+# This configuration runs wolfBoot directly from eNVM in M-mode (Machine Mode),
+# initializes DDR memory, and boots Linux from SD card.
+#
+# Boot flow:
+#   1. eNVM (0x20220100) -> L2_SCRATCH (0x0A000000) - wolfBoot starts
+#   2. DDR initialization (PLLs, controller, training)
+#   3. Load signed OS image from SD card partition to DDR
+#   4. Verify signature and boot
+#
+# Flash using mpfsBootmodeProgrammer (bootmode 1):
+#   java -jar mpfsBootmodeProgrammer.jar --bootmode 1 --die MPFS250T \
+#        --package FCG1152 --workdir $PWD wolfboot.elf
+
+ARCH?=RISCV64
+TARGET?=mpfs250
+SIGN?=ECC384
+HASH?=SHA384
+IMAGE_HEADER_SIZE=512
+WOLFBOOT_VERSION?=1
+ARMORED?=0
+DEBUG?=0
+DEBUG_SYMBOLS?=1
+DEBUG_UART?=1
+VTOR?=1
+EXT_FLASH?=0
+SPI_FLASH?=0
+NO_XIP?=1
+NVM_FLASH_WRITEONCE?=0
+UART_FLASH?=0
+V?=0
+NO_MPU?=1
+RAM_CODE?=0
+SPMATH?=1
+DUALBANK_SWAP?=0
+PKA?=0
+ENCRYPT=0
+WOLFTPM?=0
+ELF?=1
+#DEBUG_ELF?=1
+
+# M-Mode Configuration
+# Runs on E51 core in Machine Mode from L2 SRAM
+RISCV_MMODE?=1
+
+# Stack size per hart (reduced for L2 SRAM constraints)
+CFLAGS_EXTRA+=-DSTACK_SIZE_PER_HART=8192
+
+# Use RISC-V assembly version of ECDSA and SHA
+NO_ASM?=0
+NO_ARM_ASM?=0
+
+# Enable SD card for loading application
+DISK_SDCARD?=1
+DISK_EMMC?=0
+# L2 SRAM Address for wolfBoot (256KB available)
+# Stack grows down from end of L2_SCRATCH
+WOLFBOOT_ORIGIN?=0x0A000000
+
+# Flash sector size (4KB typical)
+WOLFBOOT_SECTOR_SIZE?=0x1000
+
+# Load Partition to RAM Address
+WOLFBOOT_LOAD_ADDRESS?=0x8E000000
+
+# Partition layout for PolarFire SoC MPFS250T
+# Using update_disk loader we just need to specify the partition number (A/B)
+WOLFBOOT_NO_PARTITIONS=1
+CFLAGS_EXTRA+=-DBOOT_PART_A=1
+CFLAGS_EXTRA+=-DBOOT_PART_B=2
+# Speed up disk partition read (512KB chunks - max DMA size)
+CFLAGS_EXTRA+=-DDISK_BLOCK_SIZE=0x80000
+
+# DTS (Device Tree) load address
+WOLFBOOT_LOAD_DTS_ADDRESS?=0x8A000000
+
+# Optional Encryption
+CUSTOM_ENCRYPT_KEY=1
+ENCRYPT=1
+ENCRYPT_WITH_AES256=1
+OBJS_EXTRA=src/my_custom_encrypt_key.o
+
+# Debug options (useful for initial M-mode bring-up)
+#CFLAGS_EXTRA+=-DDEBUG_BOOT
+
+# Optional EMMC_SD debugging logs
+#CFLAGS_EXTRA+=-DDEBUG_SDHCI
+# Optional disk debugging logs
+#CFLAGS_EXTRA+=-DDEBUG_DISK
+#CFLAGS_EXTRA+=-DDISK_TEST
+
+# Used by test-application for ELF
+WOLFBOOT_PARTITION_BOOT_ADDRESS=0x80200000
+WOLFBOOT_PARTITION_SIZE=0x4000000
+
+
+

config/examples/polarfire_mpfs250.config

@@ -67,17 +67,17 @@ CFLAGS_EXTRA+=-DBOOT_PART_B=2
 # Speed up disk partition read (512KB chunks - max DMA size)
 CFLAGS_EXTRA+=-DDISK_BLOCK_SIZE=0x80000
 
-# DTS (Device Tree)
+# DTS (Device Tree) load address
 WOLFBOOT_LOAD_DTS_ADDRESS?=0x8A000000
 
 # Optional Encryption
-#CUSTOM_ENCRYPT_KEY=1
-#ENCRYPT=1
-#ENCRYPT_WITH_AES256=1
-#OBJS_EXTRA=src/my_custom_encrypt_key.o
+CUSTOM_ENCRYPT_KEY=1
+ENCRYPT=1
+ENCRYPT_WITH_AES256=1
+OBJS_EXTRA=src/my_custom_encrypt_key.o
 
 # Optional EMMC_SD debugging logs
-#CFLAGS_EXTRA+=-DDEBUG_MMC
+#CFLAGS_EXTRA+=-DDEBUG_SDHCI
 # Optional disk debugging logs
 #CFLAGS_EXTRA+=-DDEBUG_DISK
 #CFLAGS_EXTRA+=-DDISK_TEST