[U-Boot] AM335x SPI boot not working

Lars Poeschel poeschel at lemonage.de
Wed Dec 16 15:34:24 CET 2015


Hi!

I played a bit with spi boot on my am3359. It is currently not working with u-
boot at least with the machine I work here. Has anyone else problems with spi 
boot on am335x ?

On boot SPL reads a value from a processor register to determine from which 
device it was booting and it uses that value to continue booting process from 
that same device.
I found, that in my case the processor register contained a 0x0b and SPL could 
not match that to a hardware device. BOOT_DEVICE_SPI is defined as 0x15 in 
arch/arm/include/asm/arch-am33xx/spl.h. SPL does not find a mathch for 0x0b, 
decides this is an unknown value and stalls. So far so good.

I looked up in the technical reference manual if the value 0x15 is correct. I 
had TRM rev. F on my harddrive and found the value in 26.1.10.2, on page 4295 
and it is indeed 0x15 as in u-boot.
I looked on TI website for a new version of the TRM and they currently have 
rev. L. There I found in 26.1.10.2 on page 4960 that SPI boot has 0x0b!

My question is now how to best cope with this issue and if anybody has more 
information on what happend.
I don't know if they only made a mistake in the TRM and fixed that or if they 
have new silicone revisions that really have another boot device value for spi 
boot.
What can we do ?

Regards,
Lars


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