Hi All.
I have been able to bring up xen on cubieboard2, using the following script gathered from google :
################################################################### # SUNXI Xen Boot Script # Arch Linux ARM adaption of the cmd file which can be found at http://openmirage.org/wiki/xen-on-cubieboard2
# Addresses suitable for 1GB system, adjust as appropriate for a 2GB system. # Top of RAM: 0x80000000 # Xen relocate addr 0x7fe00000 setenv kernel_addr_r 0x7f600000 # 10 MB setenv fdt_addr 0x7ec00000 # 2 MB setenv xen_addr_r 0x7ea00000 # 2 MB
setenv fdt_high 0xffffffff # Load fdt in place instead of relocating
# Load xen/xen to ${xen_addr_r}. fatload mmc 0 ${xen_addr_r} /xen setenv bootargs "dom0_mem=256M"
# Load appropriate .dtb file to ${fdt_addr} fatload mmc 0 ${fdt_addr} /sun7i-a20-cubieboard2.dtb fdt addr ${fdt_addr} 0x40000 fdt resize fdt chosen fdt set /chosen #address-cells <1> fdt set /chosen #size-cells <1>
# Load Linux arch/arm/boot/zImage to ${kernel_addr_r} fatload mmc 0 ${kernel_addr_r} /zImage
fdt mknod /chosen module@0 fdt set /chosen/module@0 compatible "xen,linux-zimage" "xen,multiboot-module" fdt set /chosen/module@0 reg <${kernel_addr_r} 0x${filesize} > fdt set /chosen/module@0 bootargs "console=hvc0 rw root=/dev/mmcblk0p2 rootwait clk_ignore_unused"
bootz ${xen_addr_r} - ${fdt_addr} ###################################################################
I have been able to understand most of the workflow, except three things :
a) Is the relocation-address of xen, given by # Xen relocate addr 0x7fe00000 hardcoded? Or it is computed someway from ${kernel_addr_r}, {fdt_addr}, {xen_addr_r}?
In the bootup logs, xen does relocate to 0x7fe00000, so surely there is some magic going ..
b) What does the argument 0x40000 signify in the following : fdt addr ${fdt_addr} 0x40000
I consulted https://www.denx.de/wiki/DULG/UBootCmdFDT, but did not find anything about this third argument.
c) I assume filesize is the size of the kernel-binary, but how is it determined in the following : fdt set /chosen/module@0 reg <${kernel_addr_r} 0x${filesize} >
Will be grateful for some help, as it will gain deeper understanding of the ecosystem.
Thanks and Regards, Ajay