Release 20210621

* fontamsoc-sw a0e14cb...d650dd4 (5):
  > ram initialization improvements; devtbl.PRELDRADDR now becomes null after devtbl.RRESET such that ram initialization happens only once after global reset; infinite loop after devtbl.CRESET
  > bugfix devtbl.PRELDRADDR; reduce code utilization of memtest portion
  > use devtbl.RRESET after memory initialization
  > devtbl.PRELDRADDR support
  > simplify loader

* linux 271d19984ebb...cf6067f14fc1 (1):
  > use -mzpoprp for accurate stacktrace

* improve README and makefile

README.md

@@ -30,3 +30,31 @@ Environment `PATH` must be updated as follow `PATH="${PATH}:/opt/pu32-toolchain/
 ## Running Linux in GDB
 
 	pu32-elf-gdb pu32-vmlinux -ex 'target sim --hdd pu32-rootfs.ext2' -ex 'load' -ex 'set args root=/dev/hda earlyprintk=keep' -ex 'r'
+
+## Running Linux in an FPGA
+
+Create mbr-style disk image:
+
+	sudo pu32-mksocimg -k pu32-vmlinux.bin -r pu32-rootfs.ext2 pu32-vmlinux.img
+
+Flash image to sdcard using either `dd if=pu32-vmlinux.img of=/dev/<sdx> bs=1M oflag=sync status=progress` or [BalenaEtcher](https://www.balena.io/etcher).
+
+Flash corresponding FPGA bitstream:
+- [xula2lx25](xula2lx25.bit)
+- [nexys4ddr](nexys4ddr.bit)
+
+## Reconfigure Linux kernel
+
+	make -f pu32-toolchain/makefile linux-menuconfig
+
+Rebuild the Linux kernel:
+
+	make -f pu32-toolchain/makefile touch-linux pu32-toolchain-build/.linux
+
+## Reconfigure Buildroot
+
+	make -f pu32-toolchain/makefile buildroot-menuconfig
+
+Rebuild buildroot:
+
+	make -f pu32-toolchain/makefile touch-buildroot pu32-toolchain-build/.buildroot

makefile

@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0-only
 # Contributed by William Fonkou Tambe
 
-.PHONY: all clean
+.PHONY: all linux-menuconfig buildroot-menuconfig touch-binutils touch-gcc touch-linux touch-glibc touch-buildroot touch-fontamsoc-sw clean
 
 NPROC ?= $(shell nproc)
 
@@ -85,6 +85,20 @@ pu32-toolchain.tar.xz: \
 	tar -caf pu32-toolchain.tar.xz -C /opt/ --exclude pu32-toolchain/.git pu32-toolchain && \
 		ls -lha >&2
 
+linux-menuconfig:
+	$(eval KERNEL_BUILD := "${PWD}/linux-build/")
+	$(eval KERNEL_SOURCE := "${PWD}/pu32-toolchain/linux/")
+	if [ ! -e ${KERNEL_BUILD} ]; then mkdir -p ${KERNEL_BUILD} && cd ${KERNEL_BUILD} && \
+		make -C ${KERNEL_SOURCE} O=${KERNEL_BUILD} ARCH=pu32 defconfig; fi
+	if [ -e ${KERNEL_BUILD} ]; then cd ${KERNEL_BUILD} && make ARCH=pu32 CROSS_COMPILE=pu32-elf- menuconfig; fi
+
+buildroot-menuconfig:
+	$(eval BUILDROOT_BUILD := "${PWD}/buildroot-build/")
+	$(eval BUILDROOT_SOURCE := "${PWD}/pu32-toolchain/buildroot/")
+	if [ ! -e ${BUILDROOT_BUILD} ]; then mkdir -p ${BUILDROOT_BUILD} && cd ${BUILDROOT_BUILD} && \
+		make -C ${BUILDROOT_SOURCE} O=${BUILDROOT_BUILD} pu32_defconfig; fi
+	if [ -e ${BUILDROOT_BUILD} ]; then cd ${BUILDROOT_BUILD} && make menuconfig; fi
+
 touch-binutils:
 	touch pu32-toolchain/binutils
 touch-gcc: