[U-Boot] [PATCH v2] arm: cm4008, cm41xx: set gd->ram_size in dram_init

[Andreas Bießmann]

On 05.07.2012 14:11, Yann Vernier wrote:
> Leave dram_init_banksize to set up the bank info data.
> ram_size was previously uninitialized. Also, generalize
> lowlevel assembly to support more RAM options.
> 
> Signed-off-by: Yann Vernier <yann.vernier at orsoc.se>
> ---
> Changes for v2:
>    - Update to use CONFIG_SYS_SDRAM_ constants
>    - Update cm41xx also
>    - Map SDRAM to match configuration
> ---
>  arch/arm/cpu/arm920t/ks8695/lowlevel_init.S |    8 +++-----
>  board/cm4008/cm4008.c                       |    5 +++--
>  board/cm41xx/cm41xx.c                       |    5 +++--
>  include/configs/cm4008.h                    |    5 ++---
>  include/configs/cm41xx.h                    |    5 ++---
>  5 files changed, 13 insertions(+), 15 deletions(-)
> 
> diff --git a/arch/arm/cpu/arm920t/ks8695/lowlevel_init.S b/arch/arm/cpu/arm920t/ks8695/lowlevel_init.S
> index e9f1227..df13de6 100644
> --- a/arch/arm/cpu/arm920t/ks8695/lowlevel_init.S
> +++ b/arch/arm/cpu/arm920t/ks8695/lowlevel_init.S
> @@ -131,11 +131,9 @@ highflash:
>  	 * before relocating, we have to setup RAM timing
>  	 */
>  	ldr	r1, =(KS8695_IO_BASE+KS8695_SDRAM_CTRL0)
> -#if (PHYS_SDRAM_1_SIZE == 0x02000000)
> -	ldr	r2, =0x7fc0000e		/* 32MB */
> -#else
> -	ldr	r2, =0x3fc0000e		/* 16MB */
> -#endif
> +	/* 8 column address bits, 4 banks, 32 bits data width */
> +	ldr	r2, =((CONFIG_SYS_SDRAM_BASE+CONFIG_SYS_SDRAM_SIZE-0x10000)<<(22-16) | \
> +		      (CONFIG_SYS_SDRAM_BASE>>(16-12) | 0x00e))

ugh ... magic. Will it work for every possible setting?
How about one setting CONFIG_SYS_SDRAM_BASE != 0x0? I the base address
related to register content in any way?

Would be great to have a little documentation here why it is shifted
that way, unfortunately I can not find a KS8695 spec in the net. Don't
get me wrong it is ok to do so. I think it is way better than hard
coding the values like before but would be great to understand why it is
done that way.

Best regards

Andreas Bießmann