Re: Changing U-boot relocation addres to SRAM (instead of DRAM)

8 Sep 2020

      On Mon, 2020-09-07 at 22:24 +0300, Yusuf Altıparmak wrote:
...
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Hello,
I want to modify U-boot to relocate itself to on-board SRAM of chip (T1042
demo board) instead of DRAM.
At first, there is call list in u-boot/common/board_f.c and it has a line
to call dram_init. I will change this line with my custom sram_init
function.
[image: Capture.PNG]
The function board_f() is being called in start.S which is located at
u-boot/arch/powerpc/cpu/mpc85xx/
start.S file also includes a region to relocate itself by changing Link
Register. Code region is:
*/**
** void relocate_code(addr_sp, gd, addr_moni)*

** This "function" does not return, instead it continues in RAM*
** after relocating the monitor code.*

** r3 = dest*
** r4 = src*
** r5 = length in bytes*
** r6 = cachelinesize*
**/*
*.globl relocate_code*
*relocate_code:*
*mr r1,r3 /* Set new stack pointer */*
*mr r9,r4 /* Save copy of Init Data pointer */*
*mr r10,r5 /* Save copy of Destination Address */*
*GET_GOT*
*#ifndef CONFIG_SPL_SKIP_RELOCATE*
*mr r3,r5 /* Destination Address */*
*lis r4,CONFIG_SYS_MONITOR_BASE@h /* Source Address */*
*ori r4,r4,CONFIG_SYS_MONITOR_BASE@l*
*lwz r5,GOT(__init_end)*
*sub r5,r5,r4*
*li r6,CONFIG_SYS_CACHELINE_SIZE /* Cache Line Size */*
My question is, in above code, how relocate_code() function is calculating
the jump address of Link Register (CONFIG_SYS_MONITOR_BASE@h).
What should be done to change it to point SRAM of t1042 after we initialize
it in board_init_f() function. ?
I don't think you should change anything here. Just make gd->relocaddr point to somewhere in SRAM
Jocke

Re: Changing U-boot relocation addres to SRAM (instead of DRAM)

Joakim Tjernlund