freebsd: Document how to build on FreeBSD

Signed-off-by: Daniel Schaefer <[email protected]>

README.md

@@ -123,6 +123,8 @@ cargo build -p framework_tool
 ls -l target/debug/framework_tool
 
 # Build the UEFI application
+# Needs mtools installed via your OS package manager
+# See in FreeBSD section for building on FreeBSD
 # Can't be built with cargo! That's why we need to exclude it in the other commands.
 make -C framework_uefi
 ls -l framework_uefi/build/x86_64-unknown-uefi/boot.efi
@@ -311,3 +313,14 @@ cargo build --no-default-features --features freebsd
 # Running the tool
 cargo run --no-default-features --features freebsd
 ```
+
+Build UEFI tool
+
+```
+# Build just tool
+gmake -C framework_uefi build/x86_64-unknown-uefi/boot.efi
+
+# Build QEMU image
+# TODO: Does not work yet, need a replacement for GNU parted
+gmake -C framework_uefi MKFS=newfs_msdos
+```

framework_uefi/Makefile

@@ -3,6 +3,8 @@ BUILD=build/$(TARGET)
 
 SRC_DIR=.
 
+MKFS=mkfs.vfat
+
 QEMU?=qemu-system-x86_64
 QEMU_FLAGS=\
 	-M q35 \
@@ -33,7 +35,7 @@ $(BUILD)/boot.img: $(BUILD)/efi.img
 # Create filesystem with updater (bootx64.efi)
 $(BUILD)/efi.img: $(BUILD)/boot.efi
 	dd if=/dev/zero of=$@.tmp bs=512 count=98304
-	mkfs.vfat $@.tmp
+	$(MKFS) $@.tmp
 	mmd -i $@.tmp efi
 	mmd -i $@.tmp efi/boot
 	mcopy -i $@.tmp $< ::efi/boot/bootx64.efi