opennandra
Posts: 3
Joined: Wed Jul 11, 2018 9:53 am

CM3 eMMC with u-boot not working

Wed Jul 11, 2018 9:55 am

Hi,

I'm trying to use u-boot with CM3. I build it using yocto and board can boot but it looks like that u-boot cannot work with eMMC (commands for read/write fails). Anybody here have such thing working who can share path or ideas? Thanks.

opennandra
Posts: 3
Joined: Wed Jul 11, 2018 9:53 am

Re: CM3 eMMC with u-boot not working

Fri Jul 13, 2018 6:19 am

I build image for CM3 using meta-raspberrypi and it turns out that there was wrong configuration for u-boot. BTW it's still not clear is CM3 CPU 64 bit or not? According this page it is: https://www.raspberrypi.org/documentati ... /README.md Thanks

PhilE
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 1914
Joined: Mon Sep 29, 2014 1:07 pm
Location: Cambridge

Re: CM3 eMMC with u-boot not working

Fri Jul 13, 2018 6:40 am

There should be no doubt - BCM2837 is a 64-bit capable SoC, but the standard Raspberry Pi kernel runs in 32-bit mode. While there are some nice aspects of going 64-bit, there is no clear performance benefit to justify supporting a third kernel variant.

Other distributions are available that are built for AArch64, should you wish to try one for yourself.

fruitoftheloom
Posts: 17838
Joined: Tue Mar 25, 2014 12:40 pm

Re: CM3 eMMC with u-boot not working

Fri Jul 13, 2018 6:46 am

opennandra wrote:
Fri Jul 13, 2018 6:19 am
I build image for CM3 using meta-raspberrypi and it turns out that there was wrong configuration for u-boot. BTW it's still not clear is CM3 CPU 64 bit or not? According this page it is: https://www.raspberrypi.org/documentati ... /README.md Thanks

Yes the ARMv8 CPU is 64bit AArch64:

https://en.wikipedia.org/wiki/ARM_architecture#ARMv8-A
Adieu

opennandra
Posts: 3
Joined: Wed Jul 11, 2018 9:53 am

Re: CM3 eMMC with u-boot not working

Fri Jul 13, 2018 7:22 am

OK thanks for info.

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