[U-Boot] [RFC] ARM: mx31pdk: Use the new relocation scheme

Fabio Estevam
2011-02-07T11:32:32Z

Hi Magnus,

On 2/6/2011 10:03 AM, Magnus Lilja wrote:
...

> I've done some testing now and ended up comparing start.S for ARM1136 with ARM926EJS since
> the latter is used on the Karo TX25 board which seems to have been updated and
> also boots from NAND.

Thanks for looking into this.

> The result is that applying the following patch on top of Fabios patch makes the i.MX31 PDK
> boot from NAND. Booting Linux from TFTP works nicely. However the first few lines of output
> from U-boot is missing, only the "NAND: 256 MB" line is shown. I haven't tried to understand
> how booting works nowadays and why these changes work, perhaps someone with more insight
> in the mechanisms can figure out the correct assembler code.

I think that the missing lines can be fixed by using a similar approach as to this patch:
http://git.denx.de/?p=u-boot.git;a=commitdiff;h=877eb0f91543dc5bca385bb6d22454b1d43f3e2d

> I have no idea if this breaks other boards but at least it's start for further work. I tried
> it on the imx31 litekit (which boots from NOR) but that board doesn't seem to boot even before applying Fabios patch,
> I'll see if I can figure out why that board is broken now. Don't know when though.

I will let others comment about the changes you did in arch/arm/cpu/arm1136/start.S
Will also try it later today.

Thanks,

Fabio Estevam

> Regards, Magnus Lilja
>
> diff --git a/arch/arm/cpu/arm1136/start.S b/arch/arm/cpu/arm1136/start.S
> index 12545c2..7d75ecf 100644
> --- a/arch/arm/cpu/arm1136/start.S
> +++ b/arch/arm/cpu/arm1136/start.S
> @@ -163,6 +163,9 @@ call_board_init_f:
> bic sp, sp, #7 /* 8-byte alignment for ABI compliance */
> ldr r0,=0x00000000
>
> +#if 1
> + bl board_init_f
> +#else
> #ifdef CONFIG_NAND_SPL
> bl nand_boot
> #else
> @@ -172,6 +175,7 @@ call_board_init_f:
> bl board_init_f
> #endif /* CONFIG_ONENAND_IPL */
> #endif /* CONFIG_NAND_SPL */
> +#endif
>
> /*------------------------------------------------------------------------------*/
>
> @@ -266,11 +270,19 @@ clbss_l:str r2, [r0] /* clear loop... */
> * initialization, now running from RAM.
> */
> #ifdef CONFIG_NAND_SPL
> +#if 1
> + ldr r0, _nand_boot_ofs
> + mov pc, r0
> +
> +_nand_boot_ofs:
> + .word nand_boot
> +#else
> ldr r0, _nand_boot_ofs
> adr r1, _start
> add pc, r0, r1
> _nand_boot_ofs:
> .word nand_boot - _start
> +#endif
> #else
> jump_2_ram:
> ldr r0, _board_init_r_ofs
>