[summary] compile Linux kernel for Pcduino v2

1. Version issues

It is recommended to choose the official kernel provided by Pcdunio.

Of course, you can choose the Www.github.com/linux-sunxi in the kernel, but there are a lot of drivers do not include Arduino.

I tried the following several versions, 3.29,3.79,3.90, below is my summary of these times, will slowly update.

2, the specific question (1) gen_initramfs_list.sh problem

Cannot open '. /.. /linux-sunxi/rootfs/rootfs.cpio.xz '

MAKE[1]: * * * [USR/INITRAMFS_DATA.CPIO.XZ] Error 1

Make: * * * [USR] Error 2

Create a folder structure as follows, create a hard link under roofs, and link to linux-sunxi-sunxi-v3.4.29-r1/rootfs/sun4i_rootfs.cpio.gz.

├──linux-sunxi-sunxi-v3.4.29-r1

└──rootfs

└──rootfs.cpio.xz

(2) Pcduino compiler kernel cannot boot

Pcduino start after no response, with the UART Pcduino debug, found stuck in kernel starting.

When compiling kernel to open the CONFIG_DEBUG_LL option, DEBUG with UART can see the following information:

<1>unable to handle kernel paging request at virtual address 34797474

.......
<0>kernel panic-not syncing:attempted to kill init! exitcode=0x0000000b

After reference,

Change the ARM-GNUEABIHF-GCC link from arm-gnueabihf-gcc-4.8 to arm-gnueabihf-gcc-4.7.

Reference documents:

[1]http://pcduino.com/forum/index.php?topic=3877.0