Compiling kernel

Compiling kernel

• Steps to build kernel

  1. Clone the repository by

     git clone https://github.com/androportal/linux-sunxi.git
     

  2. cd into linux-sunxi

     cd linux-sunxi
     

  3. Checkout to desired branch, it this case sunxi-3.0:

     git checkout sunxi-3.0
     

  4. Compile the a13_configuration

     make ARCH=arm a13_defconfig
     

  5. Download the latest .config file from here and keep it in the root of the kernel source code directory (change the downloaded config file back to .config)

  6. A13-OLinuXino customization can be done using(optional)

     make ARCH=arm menuconfig
     

  7. To compile kernel download and install Sourcery CodeBench Lite Edition, then issue

     make ARCH=arm CROSS_COMPILE=arm-none-linux-gnueabi- uImage
     

  8. To make kernel modules

     make ARCH=arm CROSS_COMPILE=arm-none-linux-gnueabi-
     INSTALL_MOD_PATH=out modules
     

  9. To install modules in right path

     make ARCH=arm CROSS_COMPILE=arm-none-linux-gnueabi-
     INSTALL_MOD_PATH=out modules_install
     

  10. After successful compilation uImage will be available at arch/arm/boot/uImage and also find script.bin in the root of the directory(This section is subject to change), the kernel modules are available at out/lib/modules/3.0.42+/

• Kernel on SDcard

  1. Insert sdcard in card reader or MMC reader available in laptops/netbooks

  2. Backup all your sdcard data, and issue the following commands carefully, replace X in /dev/sdX with suitable letter(a lower case alphabet) alloted for your sdcard, remember X will never be a if you have a hard disk installed, so keep in mind it must be something like /dev/sdb or /dev/sdc etc. Please check twice and if you are still unsure leave this README right now otherwise you may end up with non bootable machine

     sudo fdisk -u=sectors /dev/sdX
     

  3. Then create partition for kernel and filesystem in your sdcard, from inside fdisk prompt type p to list all partitions

     Command (m for help): p
     

  4. Now press d to delete your partition. If you have multiple partitions use partition number to delete each partition as shown by fdisk utility

     Command (m for help): d
     

  5. Type n for new partion(hit enter) and then mention p for primary partition, hit enter to continue with default starting sector(2048), enter again for last sector and mention +16M, this partition will be later formatted with vfat for kernel

     Command (m for help): n
     Partition type:
      p   primary (0 primary, 0 extended, 4 free)
      e   extended
     Select (default p): p
     Partition number (1-4, default 1):
     Using default value 1
     First sector (2048-7744511, default 2048):
     Using default value 2048
     Last sector, +sectors or +size{K,M,G} (2048-7744511, default 7744511): +16M
     

  6. The sdcard is assumed to be 4gb size, similarly create 2nd primary partition using remaining disk space which will serve as filesystem

     Command (m for help): n
     Partition type:
        p   primary (1 primary, 0 extended, 3 free)
        e   extended
     Select (default p): p
     Partition number (1-4, default 2):
     Using default value 2
     First sector (34816-7744511, default 34816):
     Using default value 34816
     Last sector, +sectors or +size{K,M,G} (34816-7744511, default 7744511):
     Using default value 7744511
     

  7. Now as we have created 2 primary partitions now let's write(w) the changes to disk. For that issue

     Command (m for help): w
     

  8. As partition is completed, we need to format them respectively, the first partition must be vfat so that uboot can read kernel

     sudo mkfs.vfat /dev/sdX1
     

     For rootfs, create ext4 partition

     sudo mkfs.ext4  /dev/sdX2
     

  9. Now mount vfat partition to some mount point(directory)

     sudo mount -t vfat /dev/sdX1 /mnt/boot
     

     copy kernel to /mnt/boot, assuming that you are still in linux-sunxi directory

     sudo cp arch/arm/boot/uImage /mnt/boot
     

     Also copy script.bin to same directory

     sudo cp script.bin /mnt/boot
     

     Now, umount /mnt/boot, before that you may want to sync so that any remaining buffers are written to disks

     sudo sync
     

     Finally unmount:

     sudo umount /mnt/boot
     

     At this point we have a sdcard read with kernel. Burn uboot and copy rootfs to make a usuable Linux for your tablet.