U-boot SPL hangs on a custom i.MX28 board

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U-boot SPL hangs on a custom i.MX28 board

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eth1
Contributor I

Hi everyone,

I am bringing up a custom board that is mostly modeled after the i.MX28EVK. The pin allocation is different, some memory and interface options have been dropped, and we're only using a 5V power supply (no battery).

I'm trying to put U-boot 2015-10 (snapshot 9ac4fc8 from git.denx.de) on the board, but the SPL hangs every time after setting the CPU and HBUS clock frequencies. Using OpenOCD I have tracked the problem down to function mxs_mem_setup_cpu_and_hbus(), specifically the last writel() call that clears the CLKCTRL_CLKSEQ_BYPASS_CPU bit. When I comment out that writel() the SPL finishes normally allowing U-boot to start up. Of course the CPU then runs at 24 MHz instead of 454 MHz :smileysad:

On the other hand clearing the EMI bypass bit seems to work without a problem, and the DRAM performs nice and stable in the U-boot memory test. Our board has a Micron MT47H64M16 DDR2 chip that is similar enough to the EDE1116 on the EVK to use the same EMI settings.

My compiler is arm-poky-linux-gnueabi-gcc 5.2.0 from a Yocto build.

Any ideas what to check next?

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eth1
Contributor I

I found out that VDDD on the board is only 1.18V even if the SPL claims to have set it to 1.50V. That's probably the reason why the CPU stops running when the CPU clock bypass is disabled.

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igorpadykov
NXP Employee
NXP Employee

Hi Esa

just for board check one can test memory with

Re: i.MX28 DDR stress test

Board Bring-up and DDR Initialization Tools

run i.MX28 EVK FSL BSP (supporting only 5V power supply (no battery) option)

Board Support Packages (5)

i.MX28 Linux 2.6.35 Source Code Files and documentation.

GZ (744.4 MB) L2.6.35_1.1.0_ER_SOURCE

http://www.freescale.com/products/arm-processors/i.mx-applications-processors-based-on-arm-cores/i.m...

then port necessary changes to used uboot version.

Best regards

igor

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fabio_estevam
NXP Employee
NXP Employee

Does it help if you add CONFIG_SYS_MXS_VDD5V_ONLY option in your board config file?

Regards,

Fabio Estevam

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eth1
Contributor I

Hi Fabio,

CONFIG_SYS_MXS_VDD5V_ONLY is already included in the board config file.

Kind regards,

Esa

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