[U-Boot] [PATCH] Revert "arm: Switch 32-bit ARM to using generic global_data setup"

[Simon Glass]

Hi Fabio,

On 10 November 2015 at 04:40, Fabio Estevam <fabio.estevam at freescale.com> wrote:
> This reverts commit 5ba534d247d418e09c5b4fe5fb7fa780aac08e49.
>
> This commit causes cgtqmx6eval to not boot anymore:
>
> U-Boot SPL 2015.10-00527-g8800bee (Nov 09 2015 - 21:23:54)
> mxc_spi: SPI Slave not allocated !
>
> Signed-off-by: Fabio Estevam <fabio.estevam at freescale.com>
> ---
>  arch/arm/lib/crt0.S | 28 ++++++++++++++++++++++++----
>  1 file changed, 24 insertions(+), 4 deletions(-)

We're at the very start the release process, so I wonder if we can try
to figure out what is wrong here?

Is it because malloc() is not working, perhaps?

The C code should be roughly equivalent to the assembly code. Albert
found a problem with the code on toolchain 5.2.1 to do with setting
'gd', so may have some thoughts on this. But this might be a different
problem.

>
> diff --git a/arch/arm/lib/crt0.S b/arch/arm/lib/crt0.S
> index 80548eb..4c3a94a 100644
> --- a/arch/arm/lib/crt0.S
> +++ b/arch/arm/lib/crt0.S
> @@ -82,11 +82,31 @@ ENTRY(_main)
>  #else
>         bic     sp, sp, #7      /* 8-byte alignment for ABI compliance */
>  #endif
> -       mov     r0, sp
> -       bl      board_init_f_mem
> -       mov     sp, r0
> -
> +       mov     r2, sp
> +       sub     sp, sp, #GD_SIZE        /* allocate one GD above SP */
> +#if defined(CONFIG_CPU_V7M)    /* v7M forbids using SP as BIC destination */
> +       mov     r3, sp
> +       bic     r3, r3, #7
> +       mov     sp, r3
> +#else
> +       bic     sp, sp, #7      /* 8-byte alignment for ABI compliance */
> +#endif
> +       mov     r9, sp          /* GD is above SP */
> +       mov     r1, sp
>         mov     r0, #0
> +clr_gd:
> +       cmp     r1, r2                  /* while not at end of GD */
> +#if defined(CONFIG_CPU_V7M)
> +       itt     lo
> +#endif
> +       strlo   r0, [r1]                /* clear 32-bit GD word */
> +       addlo   r1, r1, #4              /* move to next */
> +       blo     clr_gd
> +#if defined(CONFIG_SYS_MALLOC_F_LEN)
> +       sub     sp, sp, #CONFIG_SYS_MALLOC_F_LEN
> +       str     sp, [r9, #GD_MALLOC_BASE]
> +#endif
> +       /* mov r0, #0 not needed due to above code */
>         bl      board_init_f
>
>  #if ! defined(CONFIG_SPL_BUILD)
> --
> 1.9.1
>

Regards,
Simon