u-boot-brain/arch/arm
Siarhei Siamashka 7e40e1926a sunxi: dram: Remove broken impedance and ODT configuration code
We can safely remove it, because none of the currently supported
boards uses these features.

The existing implementation had multiple problems:
   - unnecessary code duplication between sun4i/sun5i/sun7i
   - ZQ calibration was never initiated explicitly, and could be
     only triggered by setting the highest bit in the 'zq' parameter
     in the 'dram_para' struct (this was never actually done for
     any of the known Allwinner devices).
   - even if the ZQ calibration could be started, no attempts were
     made to wait for its completion, or checking whether the
     default automatically initiated ZQ calibration is still
     in progress
   - ODT was only ever enabled on sun4i, but not on sun5i/sun7i

Additionally, SDR_IOCR was set to 0x00cc0000 only on sun4i. There
are some hints in the Rockchip Linux kernel sources, indicating
that these bits are related to the automatic I/O power down
feature, which is poorly understood on sunxi hardware at the
moment. Avoiding to set these bits on sun4i too does not seem to
have any measurable/visible impact.

The impedance and ODT configuration code will be re-introdeced in
one of the next comits.

Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>
Acked-by: Ian Campbell <ijc@hellion.org.uk>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
2014-08-12 08:42:32 +02:00
..
cpu sunxi: dram: Remove broken impedance and ODT configuration code 2014-08-12 08:42:32 +02:00
dts Merge remote-tracking branch 'u-boot-samsung/master' 2014-07-01 20:52:51 +02:00
imx-common Merge branch 'u-boot-imx/master' into 'u-boot-arm/master' 2014-06-30 23:00:34 +02:00
include/asm Merge branch 'u-boot-sunxi/master' into 'u-boot-arm/master' 2014-08-09 16:48:34 +02:00
lib arm: Support pre-relocation malloc() 2014-08-04 05:24:35 -06:00
config.mk kconfig: delete redundant CONFIG_${ARCH} definition 2014-07-30 14:42:02 -04:00
Kconfig kconfig: add board Kconfig and defconfig files 2014-07-30 08:48:01 -04:00