[Sigmastar] Add simple initramfs that boots rootfs from sdcard (#671)

Co-authored-by: Viktor <viktorxda@users.noreply.github.com>

br-ext-chip-sigmastar/linux/Config.ext.in

@@ -12,4 +12,9 @@ config BR2_LINUX_KERNEL_EXT_SIGMASTAR_PATCHER_LIST
 	help
 	  Space-separated list of patches to be applied
 
+config BR2_LINUX_KERNEL_EXT_SIGMASTAR_INITRAMFS
+	bool "SigmaStar initramfs"
+	help
+	  Simple initramfs that boots the rootfs from sdcard
+
 endif  # BR2_LINUX_KERNEL_EXT_SIGMASTAR_PATCHER

br-ext-chip-sigmastar/linux/linux-ext-sigmastar_initramfs.mk

@@ -0,0 +1,42 @@
+################################################################################
+#
+# linux-ext-sigmastar_initramfs
+#
+################################################################################
+
+LINUX_EXTENSIONS += sigmastar-initramfs
+
+SIGMASTAR_INITRAMFS_BUSYBOX_VERSION = 1.36.0
+SIGMASTAR_INITRAMFS_BUSYBOX_SOURCE = busybox-$(SIGMASTAR_INITRAMFS_BUSYBOX_VERSION).tar.bz2
+SIGMASTAR_INITRAMFS_BUSYBOX_SITE = https://www.busybox.net/downloads
+
+SIGMASTAR_INITRAMFS_DOSFSTOOLS_VERSION = 4.2
+SIGMASTAR_INITRAMFS_DOSFSTOOLS_SOURCE = dosfstools-$(SIGMASTAR_INITRAMFS_DOSFSTOOLS_VERSION).tar.gz
+SIGMASTAR_INITRAMFS_DOSFSTOOLS_SITE = https://github.com/dosfstools/dosfstools/releases/download/v$(SIGMASTAR_INITRAMFS_DOSFSTOOLS_VERSION)
+
+SIGMASTAR_INITRAMFS_BUSYBOX_PATH = $(HOST_DIR)/source/busybox-$(SIGMASTAR_INITRAMFS_BUSYBOX_VERSION)
+SIGMASTAR_INITRAMFS_DOSFSTOOLS_PATH = $(HOST_DIR)/source/dosfstools-$(SIGMASTAR_INITRAMFS_DOSFSTOOLS_VERSION)
+SIGMASTAR_INITRAMFS_TOOLCHAIN = $(PER_PACKAGE_DIR)/toolchain/host/bin/$(GNU_TARGET_NAME)-gcc
+
+define SIGMASTAR_INITRAMFS_PREPARE_KERNEL
+	mkdir -p $(LINUX_DIR)/initramfs
+	cp -f $(SIGMASTAR_INITRAMFS_PKGDIR)/files/* $(LINUX_DIR)/initramfs
+
+	wget $(SIGMASTAR_INITRAMFS_BUSYBOX_SITE)/$(SIGMASTAR_INITRAMFS_BUSYBOX_SOURCE) \
+		-P $(HOST_DIR)/source -c
+	tar -xf $(HOST_DIR)/source/$(SIGMASTAR_INITRAMFS_BUSYBOX_SOURCE) -C $(HOST_DIR)/source
+
+	wget $(SIGMASTAR_INITRAMFS_DOSFSTOOLS_SITE)/$(SIGMASTAR_INITRAMFS_DOSFSTOOLS_SOURCE) \
+		-P $(HOST_DIR)/source -c
+	tar -xf $(HOST_DIR)/source/$(SIGMASTAR_INITRAMFS_DOSFSTOOLS_SOURCE) -C $(HOST_DIR)/source
+
+	cp -f $(SIGMASTAR_INITRAMFS_PKGDIR)/files/initramfs_defconfig \
+		$(SIGMASTAR_INITRAMFS_BUSYBOX_PATH)/.config
+	$(MAKE) CC=$(SIGMASTAR_INITRAMFS_TOOLCHAIN) -C $(SIGMASTAR_INITRAMFS_BUSYBOX_PATH)
+	cp -f $(SIGMASTAR_INITRAMFS_BUSYBOX_PATH)/busybox $(LINUX_DIR)/initramfs
+
+	cd $(SIGMASTAR_INITRAMFS_DOSFSTOOLS_PATH) && ./autogen.sh && ./configure
+	$(MAKE) CC=$(SIGMASTAR_INITRAMFS_TOOLCHAIN) CFLAGS="-static -s" \
+		-C $(SIGMASTAR_INITRAMFS_DOSFSTOOLS_PATH)
+	cp -f $(SIGMASTAR_INITRAMFS_DOSFSTOOLS_PATH)/src/fsck.fat $(LINUX_DIR)/initramfs
+endef

br-ext-chip-sigmastar/package/sigmastar-initramfs

@@ -0,0 +1 @@
+../../general/package/sigmastar-initramfs

general/package/sigmastar-initramfs/Config.in

@@ -0,0 +1,2 @@
+config BR2_PACKAGE_SIGMASTAR_INITRAMFS
+	bool "sigmastar-initramfs"

general/package/sigmastar-initramfs/files/init

@@ -0,0 +1,21 @@
+#!/bin/sh
+mount -t devtmpfs devtmpfs /dev
+mount -t proc proc /proc
+mount -t sysfs sysfs /sys
+
+sleep 1
+fsck.fat -a /dev/mmcblk0p1
+mkdir -p /root /sdcard /tmp
+mount -r /dev/mmcblk0p1 /sdcard
+
+echo OpenIPC: Copy squashfs
+cp -f /sdcard/rootfs.squashfs.* /tmp || exec sh
+mount /tmp/rootfs.squashfs.* /root || exec sh
+
+umount /sdcard
+umount /dev
+umount /proc
+umount /sys
+
+echo OpenIPC: Switch to new root
+exec switch_root /root /init

general/package/sigmastar-initramfs/files/initramfs_list

@@ -0,0 +1,13 @@
+dir /bin 755 0 0
+dir /dev 755 0 0
+nod /dev/console 644 0 0 c 5 1
+dir /proc 755 0 0
+dir /sys 755 0 0
+
+file /init initramfs/init 755 0 0
+file /bin/fsck.fat initramfs/fsck.fat 755 0 0
+
+file /bin/busybox initramfs/busybox 755 0 0
+slink /bin/sh busybox 777 0 0
+slink /bin/mount busybox 777 0 0
+slink /bin/switch_root busybox 777 0 0

general/package/sigmastar-initramfs/sigmastar-initramfs.mk

@@ -0,0 +1,11 @@
+################################################################################
+#
+# sigmastar-initramfs
+#
+################################################################################
+
+SIGMASTAR_INITRAMFS_VERSION = 1.0
+SIGMASTAR_INITRAMFS_SITE =
+SIGMASTAR_INITRAMFS_SOURCE =
+
+$(eval $(generic-package))