[Arm-netbook] http://rhombus-tech.net/allwinner_a10/a10_boot_process/

[Tom Cubie]

On 12/29/2011 03:31 PM, lkcl luke wrote:
> 2011/12/29 Henrik Nordström<henrik at henriknordstrom.net>:
>> tor 2011-12-29 klockan 09:16 +0800 skrev Tom Cubie:
>>
>>> boot.axf is kind like an app of boot1, there is no asm code in boot.axf.
>>> Boot1 may also run different boot.axf which do other things like quality
>>> check or massive production. Usually boot.axf loads different OS loader.
>>> For booting linux, boot.axf just loads the kernel and jumps to the
>>> kernel entry before. But now we have u-boot, boot.axf loads u-boot,
>>> u-boot loads kernel...
>> So with u-boot available, is there any reason boot.axf is still needed?
>>
>> Do boot.axf do anything related to the hardware setup, or is it just a
>> bootloader loading a linux kernel from the FAT partition?
>   in other words, i think what you're asking is: could boot.axf (and
> anything else) be entirely skipped, and the A10 CPU somehow just load
> u-boot directly?
>
>   l.
>
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If A10 directly load the u-boot, we will have to add a head to 
u-boot.bin file, this head let brom agree to load a small part of u-boot 
to the sram then jumps to sram. Then the code in sram init sdram and 
loads the other parts of u-boot.bin to sdram. I think maybe we need a 
open source version of boot0, which init the sdram and loads u-boot to 
sdram, and u-boot do all the other things.