[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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