SAMA5D3 NOR boot lowlevel_init.S

Discussion around products based on ARM Cortex-A5 core.

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crawfish101
Posts: 7
Joined: Fri May 02, 2014 6:30 am

SAMA5D3 NOR boot lowlevel_init.S

Wed Jan 07, 2015 9:07 pm

I am trying to boot a SAMA5D3x directly from NOR flash using a u-boot designed to run XIP from NOR.  The problem is I don't know where to start making modifications to support this in u-boot.  The closest thing I see is the at91sam9263ek u-boot config file has a CONFIG_SYS_USE_BOOT_NORFLASH.  If this is defined u-boot uses a lowlevel_init.S to setup the memory timings and EBI bus settings.  Has anyone already adapted this lowlevel_init.S file to work with the SAMA5D3x.  Are there fundamental differences between the EBI bus controllers between the at91sam9263 and the sama5?
blue_z
Location: USA
Posts: 1956
Joined: Thu Apr 19, 2007 10:15 pm

Re: SAMA5D3 NOR boot lowlevel_init.S

Fri Jan 09, 2015 2:01 am

crawfish101 wrote:The problem is I don't know where to start making modifications to support this in u-boot.
You need to decide what scheme to use:
A. U-Boot is fully resident/XIP in NOR Flash;
B. U-Boot starts in NOR, and relocates itself to main memory;
C. use U-Boot's SPL capability.
crawfish101 wrote:Are there fundamental differences between the EBI bus controllers between the at91sam9263 and the sama5?
If you're incapable of finding differences in the datasheets, then comparing the initialization code from each version of AT91Bootstrap should help.

Regards

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