Obtain the yaffs2 source code and patch the kernel

First get the yaffs2 source code (refer to the detailed explanation of git command usage)

cd /work/nfs_root

git clone git@github.com:lifeyx/yaffs2.git

//If error:403 occurs during downloading, you can try vi /etc/resolv.conf and change the nameserver address to: 114.114.114.114

Configure the yaffs2 source code into the kernel (make the kernel support yaffs2)

vi /work/nfs_root/yaffs2/README-linux

Refer to the picture above:

/*Patch the kernel*/

cd /work/nfs_root/yaffs2/

./patch-ker.sh cm /work/system/linux-3.4.2//c: copy the yffs2 folder to linux-3.4.2/fs, m: specify multiple versions

/*Enable the kernel to support yaffs2 through menuconfig*/

cd /work/system/linux-3.4.2/

make menuconfig

Search for yaffs and find it located at:

-> File systems

      -> Miscellaneous filesystems (MISC_FILESYSTEMS [=y])

             <*> yaffs2 file system support //Press the Y key to enable the kernel to support yaffs2

Compile kernel make uImage

As shown in the figure below, many errors occur:

As shown in the picture above, the problem all occurs under fs/yaffs2/. Many errors report that the called member name is not defined in the struct mtd_info structure.

Modify yaffs2 source code

Next, we add the fs/yaffs2 folder to the si project of kernel 3.4. Then enter yaffs2/yaffs_vfs.c, line 1958: (yaffs_vfs.c is displayed under Linux, and vi can open yaffs_vfs.c. But in yaffs_vfs.c is not found in the si project, so copy yaffs_vfs.c from ubuntu and add it to si).

However, it was found that the structure mtd_info of struct mtd_info *mtd defines the _sync member, as shown in the following figure:

So if you encounter errors related to struct mtd_info, add them in front of the members: _

For example: Change mtd->sync in line 2514~2515 of the yaffs_vfs.c file to: mtd->_sync Change mtd->erase in line 2702 of the yaffs_vfs.c file to: mtd->_erase Change line 2703 of the yaffs_vfs.c file Change mtd->read to: mtd->_read ... ... and change root = d_alloc_root(inode); in line 2967 of yaffs_vfs.c to: root = d_make_root(inode);

After all modifications, upload yaffs_vfs.c to ubuntu, make uImage again, and the error is as follows

The kernel does not define d_alloc_root

Let's search s_root in the kernel to see how other file systems are used.

After all modifications, upload yaffs_vfs.c to ubuntu, make uImage again, and the error is as follows

I guess it's because of the missing underline.

After modification, recompile and report the same error. yaffs_mtdif1.c is not found in the SI project. Copy it from ubuntu and add it to the si project. The functions in each file in the error message above must be underlined.

Compilation error

Copy the yaffs_mtdif2.c file on ubuntu to the local if si project, continue the underscore in the above file

Finally compiled successfully

copy

cp arch/arm/boot/uIamge /work/nfs_root/uImage_yaffs

Since in the previous chapter, we created a file system named fs_mini_mdev_new, we directly used the mkyaffs2image tool to create it:

mkyaffs2image fs_mini_mdev_new fs_mini_mdev_new.yaffs2

Then we used uboot to burn yaffs2 and uImage and found that it was not successful. We used the alternative method to find the problem. There may be a problem with UBOOT: replaced it with 1.1.6 UBOOT. The file system started successfully and found that there was no problem with 1.1.6 UBOOT, so it was us. The transplanted new UBOOT has BUG:

driversmtdnandNand_util.c
if (!need_skip && !(flags & WITH_DROP_FFS)) {

Change to

if (!need_skip && !(flags & WITH_DROP_FFS) && !(flags & WITH_YAFFS_OOB)) {

Finally, yaffs2 was started successfully: