From mboxrd@z Thu Jan 1 00:00:00 1970 From: Heiko Schocher Date: Mon, 16 Nov 2015 12:02:32 +0100 Subject: [U-Boot] [PATCH 10/17] powerpc/km8321: set the DDRCDR impedance settings back to half strength In-Reply-To: <1447426768-23226-11-git-send-email-valentin.longchamp@keymile.com> References: <1447426768-23226-1-git-send-email-valentin.longchamp@keymile.com> <1447426768-23226-11-git-send-email-valentin.longchamp@keymile.com> Message-ID: <5649B7C8.7060103@denx.de> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de 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 > --- > > include/configs/km/km8321-common.h | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) Reviewed-by: Heiko Schocher 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