Upon further review, not all code authors are in favour of this change.
This reverts commit ee3556bcafbb05e59aabdc31368984e76acaabc4.

Signed-off-by: Tom Rini <trini@konsulko.com>

To make this driver easier to be reused, dual-license DDR driver.

Signed-off-by: York Sun <york.sun@nxp.com>
CC: Simon Glass <sjg@chromium.org>
CC: Tom Rini <trini@konsulko.com>
CC: Heinrich Schuchardt <xypron.glpk@gmx.de>
CC: Thomas Schaefer <thomas.schaefer@kontron.com>
CC: Masahiro Yamada <yamada.masahiro@socionext.com>
CC: Robert P. J. Day <rpjday@crashcourse.ca>
CC: Alexander Merkle <alexander.merkle@lauterbach.com>
CC: Joakim Tjernlund <joakim.tjernlund@transmode.se>
CC: Curt Brune <curt@cumulusnetworks.com>
CC: Valentin Longchamp <valentin.longchamp@keymile.com>
CC: Wolfgang Denk <wd@denx.de>
CC: Anatolij Gustschin <agust@denx.de>
CC: Ira W. Snyder <iws@ovro.caltech.edu>
CC: Marek Vasut <marek.vasut@gmail.com>
CC: Kyle Moffett <Kyle.D.Moffett@boeing.com>
CC: Sebastien Carlier <sebastien.carlier@gmail.com>
CC: Stefan Roese <sr@denx.de>
CC: Peter Tyser <ptyser@xes-inc.com>
CC: Paul Gortmaker <paul.gortmaker@windriver.com>
CC: Peter Tyser <ptyser@xes-inc.com>
CC: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>

Variable "row_density" is no longer used. Drop it from DIMM structure.

Signed-off-by: York Sun <york.sun@nxp.com>

DDR controllers always use binding register to determine the memory
space to perform data initialization. In case of controller interleaving,
the space is doubled, resulting twice long wait. It wasn't too bad until
the memory capacity increases. To reduce the wait time, reduce the
binding space to half and restore it after data initialization.
Three-way interleaving is no longer used and is removed.

Signed-off-by: York Sun <york.sun@nxp.com>

DDR4 RDIMM has some information in SPD to be used to calculate the
control words for register chip. The rest can be found from JEDEC
spec DDR4RCD02.

Signed-off-by: York Sun <york.sun@nxp.com>

On top of RDIMM support, add new register calculation to support
3DS RDIMMs. Only symmetrical 3DS is supported at this time.

Signed-off-by: York Sun <york.sun@nxp.com>

Wrong field was masked in this workaround due to wrong endianness. The
impacted SoCs have big-endian.

Signed-off-by: York Sun <york.sun@nxp.com>

For DDR4, command/address delay in mode registers and parity latency
in timing config register are only needed for UDIMMs, but not RDIMMs.
Add additional register rcw_3 for DDR4 RDIMM. Fix mirrored bit for
dual rank RDIMMs. Set sdram_cfg_3[DIS_MRS_PAR] for RDIMMs. Fix
calculation of timing config registers. Use hexadecimal format for
printing RCW (register control word) registers.

Signed-off-by: York Sun <york.sun@nxp.com>