i.MX ProcessorsのトピックRe: Does the u-boot copy itself to DRAM or the ROM code copies u-boot to DRAM ?

Does the u-boot copy itself to DRAM or the ROM code copies u-boot to DRAM ?

adityanagal — Thu, 06 Apr 2017 12:44:13 GMT

Hi ,

I am working on IMX6 solo based target board. Considering NOR flash is interfaced with IMX6 solo ,

when the CPU boots up , it checks for the IVT (Image Vector Table) in the NOR Flash , calculate the offset as per the NOR Flash , add it to the base address and then jump to the DCD table( Device Configuration data ) , read the configuration registers and initialize the peripheral .

My questions are :

1) once the DRAM is initialsed by the ROM , does the u-boot copies/loads itself to the DRAM or the ROM copies/loads the u-boot to the DRAM ?

2) Do the some instructions get executed directly from the NOR flash prior relocating the u-boot to the DRAM ?

Kindly suggest

Regards ,

Aditya Nagal

Re: Does the u-boot copy itself to DRAM or the ROM code copies u-boot to DRAM ?

marius_grigoras — Thu, 06 Apr 2017 15:11:49 GMT

Hi,

1. u-boot copies/loads itself to the DRAM

2. yes, of course.

These are the main points in the code for u-boot:

_start

reset

relocate_code

relocate_done

U-boot code relocate itself to the DRAM memory between relocate_code and relocate_done, the execute some steps for preparing the call to linux kernel.

Regards,

Marius

Re: Does the u-boot copy itself to DRAM or the ROM code copies u-boot to DRAM ?

adityanagal — Fri, 07 Apr 2017 11:39:16 GMT

Thanks a lot!!

Regard,

Aditya Nagal