[U-Boot] [PATCH 10/17] powerpc/km8321: set the DDRCDR impedance settings back to half strength

Heiko Schocher
2015-11-16T11:02:32Z

Hello Valentin,

Am 13.11.2015 um 15:59 schrieb Valentin Longchamp:
> The impedance settings have been changed with commit
> 2ea8ae99595ca11dd228726e854ebc6268208601 (whose goal was to set
> the internal voltage level to the DDR2 value - and not DDR1).
>
> There was no other good reason to set them to nominal strength than
> "the others do it like that" according to Ludger. The others however
> very often use DIMM modules where the nominal strength makes sense.
>
> In our case where the DRAM chips are soldered on board and the routing
> for these signals under control, half-strength is sufficient as a few
> measurements done in the lasts have shown. Since all the hardware
> qualification tests have been performed with half strength, the nominal
> strength settings are removed in favor of the default reset half
> strength settings.
>
> Signed-off-by: Valentin Longchamp <valentin.longchamp@keymile.com>
> ---
>
> include/configs/km/km8321-common.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)

Reviewed-by: Heiko Schocher <hs@denx.de>

bye,
Heiko
>
> diff --git a/include/configs/km/km8321-common.h b/include/configs/km/km8321-common.h
> index 6f21c05..b2e68e3 100644
> --- a/include/configs/km/km8321-common.h
> +++ b/include/configs/km/km8321-common.h
> @@ -67,8 +67,8 @@
>
> #define CONFIG_SYS_DDRCDR (\
> DDRCDR_EN | \
> - DDRCDR_PZ_NOMZ | \
> - DDRCDR_NZ_NOMZ | \
> + DDRCDR_PZ_MAXZ | \
> + DDRCDR_NZ_MAXZ | \
> DDRCDR_M_ODR)
>
> #define CONFIG_SYS_DDR_CS0_BNDS 0x0000007f
>

--
DENX Software Engineering GmbH, Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany