feat(file system): add memory-based romfs

1, this RomFS's codebase is Nuttx romfs, then it is compatible with
Linux RomFS and you can create such a file system using the tool genromfs.
2, there are two major changes against with the original Nuttx romfs:
    1), it is memory-based: all contents of the fs are stored in the
        memory in the very first stage of "mount".
    2), this version of romfs is altered to be compatible with our new
        version of VFS to take advantage of vnode cache and path cache.

close: #I3S0CP

Kconfig

@@ -90,6 +90,7 @@ menu "FileSystem"
 source "../../kernel/liteos_a/fs/vfs/Kconfig"
 source "../../kernel/liteos_a/fs/fat/Kconfig"
 source "../../kernel/liteos_a/fs/ramfs/Kconfig"
+source "../../kernel/liteos_a/fs/romfs/Kconfig"
 source "../../kernel/liteos_a/fs/nfs/Kconfig"
 source "../../kernel/liteos_a/fs/proc/Kconfig"
 source "../../kernel/liteos_a/fs/jffs2/Kconfig"

fs/romfs/Kconfig

+config FS_ROMFS
+    bool "Enable ROMFS"
+    default n
+    depends on FS_VFS
+    help
+      Answer Y to enable LiteOS support romfs filesystem.

fs/romfs/Makefile

+# Copyright (c) 2021-2021 Huawei Device Co., Ltd. All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without modification,
+# are permitted provided that the following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice, this list of
+#    conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice, this list
+#    of conditions and the following disclaimer in the documentation and/or other materials
+#    provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors may be used
+#    to endorse or promote products derived from this software without specific prior written
+#    permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+# THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
+# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+# EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+# PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+# OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+# WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+# OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+# ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+include $(LITEOSTOPDIR)/config.mk
+
+MODULE_NAME := $(notdir $(shell pwd))
+
+LOCAL_SRCS := $(wildcard $(LITEOSTHIRDPARTY)/NuttX/fs/romfs/*.c)
+
+LOCAL_FLAGS := $(LOCAL_INCLUDE) $(LITEOS_GCOV_OPTS)
+
+include $(MODULE)

tools/build/mk/liteos_tables_ldflags.mk

@@ -146,6 +146,7 @@ LITEOS_TABLES_DRIVER_LDFLAGS := \
 ####FS MAP####
 LITEOS_TABLES_FSMAP_LDFLAGS := \
     -uramfs_fsmap \
+    -uromfs_fsmap \
     -unfs_fsmap \
     -ufat_fsmap \
     -ujffs_fsmap \

tools/build/mk/los_config.mk

@@ -325,6 +325,11 @@ ifeq ($(LOSCFG_FS_RAMFS), y)
     LIB_SUBDIRS     += fs/ramfs
 endif
 
+ifeq ($(LOSCFG_FS_ROMFS), y)
+    LITEOS_BASELIB  += -lromfs
+    LIB_SUBDIRS     += fs/romfs
+endif
+
 ifeq ($(LOSCFG_FS_NFS), y)
     LITEOS_BASELIB  += -lnfs
     LIB_SUBDIRS     += fs/nfs

tools/scripts/make_rootfs/rootfsimg.sh

@@ -38,6 +38,7 @@ JFFS2_TOOL=mkfs.jffs2
 WIN_JFFS2_TOOL=mkfs.jffs2.exe
 YAFFS2_TOOL=mkyaffs2image100
 VFAT_TOOL=mkfs.vfat
+ROMFS_TOOL=genromfs
 MCOPY_TOOL=mcopy
 
 tool_check() {
@@ -66,8 +67,11 @@ if [ "${FSTYPE}" = "jffs2" ]; then
         ${JFFS2_TOOL} -q -o ${ROOTFS_IMG} -d ${ROOTFS_DIR} --pagesize=4096
     fi
 elif [ "${FSTYPE}" = "yaffs2" ]; then
-        tool_check ${YAFFS2_TOOL}
-	${YAFFS2_TOOL}  ${ROOTFS_DIR} ${ROOTFS_IMG} 2k 24bit
+    tool_check ${YAFFS2_TOOL}
+    ${YAFFS2_TOOL}  ${ROOTFS_DIR} ${ROOTFS_IMG} 2k 24bit
+elif [ "${FSTYPE}" = "romfs" ]; then
+    tool_check ${ROMFS_TOOL}
+    ${ROMFS_TOOL}  -d ${ROOTFS_DIR} -f ${ROOTFS_IMG}
 elif [ "${FSTYPE}" = "vfat" ]; then
     if [ "${system}" != "Linux" ] ; then
         echo "Unsupported fs type!" >&2