Overview
Linux kernel for SBC-SAM9G45 modules provides support for on-board peripherals and abstracts the functionality provided by the hardware. Corewindprovides ready-to-run binary kernel images, and source code of the modifications and additions made to the Linux kernel to work properly with SBC-SAM9G45 modules.
If you want to compile the Bootloader for SBC-SAM9G45, see the Bootloader Devlopment for SBC-SAM9G45
Kernel command line
The Linux kernel for SBC-SAM9G45 is shipped with built-in command line parameters:
bootargs=noinitrd console=ttySAC6,115200 LcdMode=480x272MR-16@60 root=/dev/mtdblock2 rw rootfstype=yaffs2
The default kernel command line defines primary console, default display settings, root device and root filesystem type. Setting U-Boot bootargs environment variable overrides default kernel command line and can be used to set desired kernel parameters.
Building kernel for SBC-SAM9G45
Step 1.Prepare the Cross Compile tools
Copy the arm-2007q1-10-arm-none-linux-gnueabi-i686-pc-linux-gnu.tar.bz2 to /tmp folder, and uncompress it as follow:
# cd /tmp
# sudo tar xvjf arm-2007q1-10-arm-none-linux-gnueabi-i686-pc-linux-gnu.tar.bz2 -C /
 |
arm-2007q1-10-arm-none-linux-gnueabi-i686-pc-linux-gnu.tar.bz2 Position: CD:/linux/tools, Or [Download it here] |
Step 2.Building the kernel
copy the file linux-2.6.30.tar.bz2 From CD to ubuntu system in PC.
# mkdir sam9g45
# cd sam9g45
# cp -a /media/cdrom/linux/code/linux-2.6.30.tar.bz2 .
# tar -xjf linux-2.6.30.tar.bz2 -C
# cd linux-2.6.30
Then we can get the linux-2.6.30 folders in Linux folder, run the command to compile it:
# make sam9g45_defconfig
# make uImage
If there is no error, uImage should have been generated with a file size of about 1.5M-2Mbyte. you can get it in Arch/arm/boot folder.
Step 3. Building Root File System
The file rootfs.tar.bz2 was the filesystem, and we can edit it and then compress it.
Run the follow command to uncompress it and make it.
# cd sam9g45
# cp -a /media/cdrom/linux/image/rootfs.tar.bz2 .
# cp -a /media/cdrom/linux/image/tools.tar.bz2 .
# tar -xjf tools.tar.bz2 -C ./
# sudo tar -xjf rootfs.tar.bz2 -C ./
# sudo ./tools/mkyaffs2image ./rootfs rootfs.yaffs2
Then you can get the rootfs.yaffs2 on the sam9g45 folder.
Image address in the Flash
The Linux image contains 4 parts, namely bootloader, kernel, rootfs, this chapter will introduce the method to burning the image to the board
The Address for the parts was as follow:
|
Position |
Start Address |
Size |
Usage |
|
DataFlash |
0xC0000000 |
0x4200 |
Boot strap code |
|
DataFlash |
C0004200 |
0x4200 |
U-boot environment |
|
DataFlash |
0xC0008400 |
0x39C00 |
U-boot |
|
Nand Flash |
0x0000 |
0x200000 |
logo |
|
Nand Flash |
0x200000 |
0x200000 |
Linux kernel |
|
Nand Flash |
0x400000 |
-- |
Root file system
|
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