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

Valentin Longchamp
2015-11-13T14:59:21Z

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(-)

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
--
1.8.3.1