Table of interleaving 2-4 controllers
=====================================
  +--------------+-----------------------------------------------------------+
  |Configuration |                    Memory Controller                      |
  |              |       1              2              3             4       |
  |--------------+--------------+--------------+-----------------------------+
  | Two memory   | Not Intlv'ed | Not Intlv'ed |                             |
  | complexes    +--------------+--------------+                             |
  |              |      2-way Intlv'ed         |                             |
  |--------------+--------------+--------------+--------------+              |
  |              | Not Intlv'ed | Not Intlv'ed | Not Intlv'ed |              |
  | Three memory +--------------+--------------+--------------+              |
  | complexes    |         2-way Intlv'ed      | Not Intlv'ed |              |
  |              +-----------------------------+--------------+              |
  |              |                  3-way Intlv'ed            |              |
  +--------------+--------------+--------------+--------------+--------------+
  |              | Not Intlv'ed | Not Intlv'ed | Not Intlv'ed | Not Intlv'ed |
  | Four memory  +--------------+--------------+--------------+--------------+
  | complexes    |       2-way Intlv'ed        |       2-way Intlv'ed        |
  |              +-----------------------------+-----------------------------+
  |              |                      4-way Intlv'ed                       |
  +--------------+-----------------------------------------------------------+


Table of 2-way interleaving modes supported in cpu/8xxx/ddr/
======================================================
  +-------------+---------------------------------------------------------+
  |             |                   Rank Interleaving                     |
  |             +--------+-----------+-----------+------------+-----------+
  |Memory       |        |           |           |    2x2     |    4x1    |
  |Controller   |  None  | 2x1 lower | 2x1 upper | {CS0+CS1}, | {CS0+CS1+ |
  |Interleaving |        | {CS0+CS1} | {CS2+CS3} | {CS2+CS3}  |  CS2+CS3} |
  +-------------+--------+-----------+-----------+------------+-----------+
  |None         |  Yes   | Yes       | Yes       | Yes        | Yes       |
  +-------------+--------+-----------+-----------+------------+-----------+
  |Cacheline    |  Yes   | Yes       | No        | No, Only(*)| Yes       |
  |             |CS0 Only|           |           | {CS0+CS1}  |           |
  +-------------+--------+-----------+-----------+------------+-----------+
  |Page         |  Yes   | Yes       | No        | No, Only(*)| Yes       |
  |             |CS0 Only|           |           | {CS0+CS1}  |           |
  +-------------+--------+-----------+-----------+------------+-----------+
  |Bank         |  Yes   | Yes       | No        | No, Only(*)| Yes       |
  |             |CS0 Only|           |           | {CS0+CS1}  |           |
  +-------------+--------+-----------+-----------+------------+-----------+
  |Superbank    |  No    | Yes       | No        | No, Only(*)| Yes       |
  |             |        |           |           | {CS0+CS1}  |           |
  +-------------+--------+-----------+-----------+------------+-----------+
 (*) Although the hardware can be configured with memory controller
 interleaving using "2x2" rank interleaving, it only interleaves {CS0+CS1}
 from each controller. {CS2+CS3} on each controller are only rank
 interleaved on that controller.

 For memory controller interleaving, identical DIMMs are suggested. Software
 doesn't check the size or organization of interleaved DIMMs.

The ways to configure the ddr interleaving mode
==============================================
1. In board header file(e.g.MPC8572DS.h), add default interleaving setting
   under "CONFIG_EXTRA_ENV_SETTINGS", like:
        #define CONFIG_EXTRA_ENV_SETTINGS                               \
         "hwconfig=fsl_ddr:ctlr_intlv=bank"                     \
         ......

2. Run U-Boot "setenv" command to configure the memory interleaving mode.
   Either numerical or string value is accepted.

  # disable memory controller interleaving
  setenv hwconfig "fsl_ddr:ctlr_intlv=null"

  # cacheline interleaving
  setenv hwconfig "fsl_ddr:ctlr_intlv=cacheline"

  # page interleaving
  setenv hwconfig "fsl_ddr:ctlr_intlv=page"

  # bank interleaving
  setenv hwconfig "fsl_ddr:ctlr_intlv=bank"

  # superbank
  setenv hwconfig "fsl_ddr:ctlr_intlv=superbank"

  # 1KB 3-way interleaving
  setenv hwconfig "fsl_ddr:ctlr_intlv=3way_1KB"

  # 4KB 3-way interleaving
  setenv hwconfig "fsl_ddr:ctlr_intlv=3way_4KB"

  # 8KB 3-way interleaving
  setenv hwconfig "fsl_ddr:ctlr_intlv=3way_8KB"

  # disable bank (chip-select) interleaving
  setenv hwconfig "fsl_ddr:bank_intlv=null"

  # bank(chip-select) interleaving cs0+cs1
  setenv hwconfig "fsl_ddr:bank_intlv=cs0_cs1"

  # bank(chip-select) interleaving cs2+cs3
  setenv hwconfig "fsl_ddr:bank_intlv=cs2_cs3"

  # bank(chip-select) interleaving (cs0+cs1) and (cs2+cs3)  (2x2)
  setenv hwconfig "fsl_ddr:bank_intlv=cs0_cs1_and_cs2_cs3"

  # bank(chip-select) interleaving (cs0+cs1+cs2+cs3) (4x1)
  setenv hwconfig "fsl_ddr:bank_intlv=cs0_cs1_cs2_cs3"

  # bank(chip-select) interleaving (auto)
  setenv hwconfig "fsl_ddr:bank_intlv=auto"
  This auto mode only select from cs0_cs1_cs2_cs3, cs0_cs1, null dependings
  on DIMMs.

Memory controller address hashing
==================================
If the DDR controller supports address hashing, it can be enabled by hwconfig.

Syntax is:
hwconfig=fsl_ddr:addr_hash=true

Memory controller ECC on/off
============================
If ECC is enabled in board configuratoin file, i.e. #define CONFIG_DDR_ECC,
ECC can be turned on/off by hwconfig.

Syntax is
hwconfig=fsl_ddr:ecc=off


Memory address parity on/off
============================
address parity can be turned on/off by hwconfig.
Syntax is:
hwconfig=fsl_ddr:parity=on


Memory testing options for mpc85xx
==================================
1. Memory test can be done once U-Boot prompt comes up using mtest, or
2. Memory test can be done with Power-On-Self-Test function, activated at
   compile time.

   In order to enable the POST memory test, CONFIG_POST needs to be
   defined in board configuraiton header file. By default, POST memory test
   performs a fast test. A slow test can be enabled by changing the flag at
   compiling time. To test memory bigger than 2GB, 36BIT support is needed.
   Memory is tested within a 2GB window. TLBs are used to map the virtual 2GB
   window to physical address so that all physical memory can be tested.

Combination of hwconfig
=======================
Hwconfig can be combined with multiple parameters, for example, on a supported
platform

hwconfig=fsl_ddr:addr_hash=true,ctlr_intlv=cacheline,bank_intlv=cs0_cs1_cs2_cs3,ecc=on


Table for dynamic ODT for DDR3
==============================
For single-slot system with quad-rank DIMM and dual-slot system, dynamic ODT may
be needed, depending on the configuration. The numbers in the following tables are
in Ohms.

* denotes dynamic ODT

Two slots system
+-----------------------+----------+---------------+-----------------------------+-----------------------------+
|     Configuration     |          |DRAM controller|           Slot 1            |            Slot 2           |
+-----------+-----------+----------+-------+-------+--------------+--------------+--------------+--------------+
|           |           |          |       |       |     Rank 1   |     Rank 2   |   Rank 1     |    Rank 2    |
+  Slot 1   |   Slot 2  |Write/Read| Write | Read  |-------+------+-------+------+-------+------+-------+------+
|           |           |          |       |       | Write | Read | Write | Read | Write | Read | Write | Read |
+-----------+-----------+----------+-------+-------+-------+------+-------+------+-------+------+-------+------+
|           |           |  Slot 1  |  off  | 75    | 120   | off  | off   | off  | off   | off  | 30    | 30   |
| Dual Rank | Dual Rank |----------+-------+-------+-------+------+-------+------+-------+------+-------+------+
|           |           |  Slot 2  |  off  | 75    | off   | off  | 30    | 30   | 120   | off  | off   | off  |
+-----------+-----------+----------+-------+-------+-------+------+-------+------+-------+------+-------+------+
|           |           |  Slot 1  |  off  | 75    | 120   | off  | off   | off  | 20    | 20   |       |      |
| Dual Rank |Single Rank|----------+-------+-------+-------+------+-------+------+-------+------+-------+------+
|           |           |  Slot 2  |  off  | 75    | off   | off  | 20    | 20   | 120  *| off  |       |      |
+-----------+-----------+----------+-------+-------+-------+------+-------+------+-------+------+-------+------+
|           |           |  Slot 1  |  off  | 75    | 120  *| off  |       |      | off   | off  | 20    | 20   |
|Single Rank| Dual Rank |----------+-------+-------+-------+------+-------+------+-------+------+-------+------+
|           |           |  Slot 2  |  off  | 75    | 20    | 20   |       |      | 120   | off  | off   | off  |
+-----------+-----------+----------+-------+-------+-------+------+-------+------+-------+------+-------+------+
|           |           |  Slot 1  |  off  | 75    | 120  *| off  |       |      | 30    | 30   |       |      |
|Single Rank|Single Rank|----------+-------+-------+-------+------+-------+------+-------+------+-------+------+
|           |           |  Slot 2  |  off  | 75    | 30    | 30   |       |      | 120  *| off  |       |      |
+-----------+-----------+----------+-------+-------+-------+------+-------+------+-------+------+-------+------+
| Dual Rank |   Empty   |  Slot 1  |  off  | 75    | 40    | off  | off   | off  |       |      |       |      |
+-----------+-----------+----------+-------+-------+-------+------+-------+------+-------+------+-------+------+
|   Empty   | Dual Rank |  Slot 2  |  off  | 75    |       |      |       |      | 40    | off  | off   | off  |
+-----------+-----------+----------+-------+-------+-------+------+-------+------+-------+------+-------+------+
|Single Rank|   Empty   |  Slot 1  |  off  | 75    | 40    | off  |       |      |       |      |       |      |
+-----------+-----------+----------+-------+-------+-------+------+-------+------+-------+------+-------+------+
|   Empty   |Single Rank|  Slot 2  |  off  | 75    |       |      |       |      | 40    | off  |       |      |
+-----------+-----------+----------+-------+-------+-------+------+-------+------+-------+------+-------+------+

Single slot system
+-------------+------------+---------------+-----------------------------+-----------------------------+
|             |            |DRAM controller|     Rank 1   |    Rank 2    |    Rank 3    |    Rank 4    |
|Configuration| Write/Read |-------+-------+-------+------+-------+------+-------+------+-------+------+
|             |            | Write | Read  | Write | Read | Write | Read | Write | Read | Write | Read |
+-------------+------------+-------+-------+-------+------+-------+------+-------+------+-------+------+
|             |   R1       | off   | 75    | 120  *| off  | off   | off  | 20    | 20   | off   | off  |
|             |------------+-------+-------+-------+------+-------+------+-------+------+-------+------+
|             |   R2       | off   | 75    | off   | 20   | 120   | off  | 20    | 20   | off   | off  |
|  Quad Rank  |------------+-------+-------+-------+------+-------+------+-------+------+-------+------+
|             |   R3       | off   | 75    | 20    | 20   | off   | off  | 120  *| off  | off   | off  |
|             |------------+-------+-------+-------+------+-------+------+-------+------+-------+------+
|             |   R4       | off   | 75    | 20    | 20   | off   | off  | off   | 20   | 120   | off  |
+-------------+------------+-------+-------+-------+------+-------+------+-------+------+-------+------+
|             |   R1       | off   | 75    | 40    | off  | off   | off  |
|  Dual Rank  |------------+-------+-------+-------+------+-------+------+
|             |   R2       | off   | 75    | 40    | off  | off   | off  |
+-------------+------------+-------+-------+-------+------+-------+------+
| Single Rank |   R1       | off   | 75    | 40    | off  |
+-------------+------------+-------+-------+-------+------+

Reference http://www.xrosstalkmag.com/mag_issues/xrosstalk_oct08_final.pdf
          http://download.micron.com/pdf/technotes/ddr3/tn4108_ddr3_design_guide.pdf


Table for ODT for DDR2
======================
Two slots system
+-----------------------+----------+---------------+-----------------------------+-----------------------------+
|     Configuration     |          |DRAM controller|           Slot 1            |            Slot 2           |
+-----------+-----------+----------+-------+-------+--------------+--------------+--------------+--------------+
|           |           |          |       |       |     Rank 1   |     Rank 2   |   Rank 1     |    Rank 2    |
+  Slot 1   |   Slot 2  |Write/Read| Write | Read  |-------+------+-------+------+-------+------+-------+------+
|           |           |          |       |       | Write | Read | Write | Read | Write | Read | Write | Read |
+-----------+-----------+----------+-------+-------+-------+------+-------+------+-------+------+-------+------+
|           |           |  Slot 1  |  off  | 150   | off   | off  | off   | off  | 75    | 75   | off   | off  |
| Dual Rank | Dual Rank |----------+-------+-------+-------+------+-------+------+-------+------+-------+------+
|           |           |  Slot 2  |  off  | 150   | 75    | 75   | off   | off  | off   | off  | off   | off  |
+-----------+-----------+----------+-------+-------+-------+------+-------+------+-------+------+-------+------+
|           |           |  Slot 1  |  off  | 150   | off   | off  | off   | off  | 75    | 75   |       |      |
| Dual Rank |Single Rank|----------+-------+-------+-------+------+-------+------+-------+------+-------+------+
|           |           |  Slot 2  |  off  | 150   | 75    | 75   | off   | off  | off   | off  |       |      |
+-----------+-----------+----------+-------+-------+-------+------+-------+------+-------+------+-------+------+
|           |           |  Slot 1  |  off  | 150   | off   | off  |       |      | 75    | 75   | off   | off  |
|Single Rank| Dual Rank |----------+-------+-------+-------+------+-------+------+-------+------+-------+------+
|           |           |  Slot 2  |  off  | 150   | 75    | 75   |       |      | off   | off  | off   | off  |
+-----------+-----------+----------+-------+-------+-------+------+-------+------+-------+------+-------+------+
|           |           |  Slot 1  |  off  | 150   | off   | off  |       |      | 75    | 75   |       |      |
|Single Rank|Single Rank|----------+-------+-------+-------+------+-------+------+-------+------+-------+------+
|           |           |  Slot 2  |  off  | 150   | 75    | 75   |       |      | off   | off  |       |      |
+-----------+-----------+----------+-------+-------+-------+------+-------+------+-------+------+-------+------+
| Dual Rank |   Empty   |  Slot 1  |  off  | 75    | 150   | off  | off   | off  |       |      |       |      |
+-----------+-----------+----------+-------+-------+-------+------+-------+------+-------+------+-------+------+
|   Empty   | Dual Rank |  Slot 2  |  off  | 75    |       |      |       |      | 150   | off  | off   | off  |
+-----------+-----------+----------+-------+-------+-------+------+-------+------+-------+------+-------+------+
|Single Rank|   Empty   |  Slot 1  |  off  | 75    | 150   | off  |       |      |       |      |       |      |
+-----------+-----------+----------+-------+-------+-------+------+-------+------+-------+------+-------+------+
|   Empty   |Single Rank|  Slot 2  |  off  | 75    |       |      |       |      | 150   | off  |       |      |
+-----------+-----------+----------+-------+-------+-------+------+-------+------+-------+------+-------+------+

Single slot system
+-------------+------------+---------------+-----------------------------+
|             |            |DRAM controller|     Rank 1   |    Rank 2    |
|Configuration| Write/Read |-------+-------+-------+------+-------+------+
|             |            | Write | Read  | Write | Read | Write | Read |
+-------------+------------+-------+-------+-------+------+-------+------+
|             |   R1       | off   | 75    | 150   | off  | off   | off  |
|  Dual Rank  |------------+-------+-------+-------+------+-------+------+
|             |   R2       | off   | 75    | 150   | off  | off   | off  |
+-------------+------------+-------+-------+-------+------+-------+------+
| Single Rank |   R1       | off   | 75    | 150   | off  |
+-------------+------------+-------+-------+-------+------+

Reference http://www.samsung.com/global/business/semiconductor/products/dram/downloads/applicationnote/ddr2_odt_control_200603.pdf


Interactive DDR debugging
===========================

For DDR parameter tuning up and debugging, the interactive DDR debugger can
be activated by setting the environment variable "ddr_interactive" to any
value.  (The value of ddr_interactive may have a meaning in the future, but,
for now, the presence of the variable will cause the debugger to run.)  Once
activated, U-Boot will show the prompt "FSL DDR>" before enabling the DDR
controller.  The available commands are printed by typing "help".

Another way to enter the interactive DDR debugger without setting the
environment variable is to send the 'd' character early during the boot
process.  To save booting time, no additional delay is added, so the window
to send the key press is very short -- basically, it is the time before the
memory controller code starts to run.  For example, when rebooting from
within U-Boot, the user must press 'd' IMMEDIATELY after hitting enter to
initiate a 'reset' command.  In case of power on/reset, the user can hold
down the 'd' key while applying power or hitting the board's reset button.

The example flow of using interactive debugging is
type command "compute" to calculate the parameters from the default
type command "print" with arguments to show SPD, options, registers
type command "edit" with arguments to change any if desired
type command "copy" with arguments to copy controller/dimm settings
type command "go" to continue calculation and enable DDR controller

Additional commands to restart the debugging are:
type command "reset" to reset the board
type command "recompute" to reload SPD and start over

Note, check "next_step" to show the flow. For example, after edit opts, the
next_step is STEP_ASSIGN_ADDRESSES. After editing registers, the next_step is
STEP_PROGRAM_REGS.  Upon issuing command "go", the debugger will program the
DDR controller with the current setting without further calculation and then
exit to resume the booting of the machine.

The detail syntax for each commands are

print [c<n>] [d<n>] [spd] [dimmparms] [commonparms] [opts] [addresses] [regs]
        c<n>            - the controller number, eg. c0, c1
        d<n>            - the DIMM number, eg. d0, d1
        spd             - print SPD data
        dimmparms       - DIMM parameters, calculated from SPD
        commonparms     - lowest common parameters for all DIMMs
        opts            - options
        addresses       - address assignment (not implemented yet)
        regs            - controller registers

edit <c#> <d#> <spd|dimmparms|commonparms|opts|addresses|regs> <element> <value>
        c<n>            - the controller number, eg. c0, c1
        d<n>            - the DIMM number, eg. d0, d1
        spd             - print SPD data
        dimmparms       - DIMM parameters, calculated from SPD
        commonparms     - lowest common parameters for all DIMMs
        opts            - options
        addresses       - address assignment (not implemented yet)
        regs            - controller registers
        <element>       - name of the modified element
                          byte number if the object is SPD
        <value>         - decimal or heximal (prefixed with 0x) numbers

copy <src c#> <src d#> <spd|dimmparms|commonparms|opts|addresses|regs> <dst c#> <dst d#>
        same as for "edit" command
        DIMM numbers ignored for commonparms, opts, and regs

reset
        no arguement    - reset the board

recompute
        no argument     - reload SPD and start over

compute
        no argument     - recompute from current next_step

next_step
        no argument     - show current next_step

help
        no argument     - print a list of all commands

go
        no argument     - program memory controller(s) and continue with U-Boot

Examples of debugging flow

        FSL DDR>compute
        Detected UDIMM UG51U6400N8SU-ACF
        FSL DDR>print
        print [c<n>] [d<n>] [spd] [dimmparms] [commonparms] [opts] [addresses] [regs]
        FSL DDR>print dimmparms
        DIMM parameters:  Controller=0 DIMM=0
        DIMM organization parameters:
        module part name = UG51U6400N8SU-ACF
        rank_density = 2147483648 bytes (2048 megabytes)
        capacity = 4294967296 bytes (4096 megabytes)
        burst_lengths_bitmask = 0C
        base_addresss = 0 (00000000 00000000)
        n_ranks = 2
        data_width = 64
        primary_sdram_width = 64
        ec_sdram_width = 0
        registered_dimm = 0
        n_row_addr = 15
        n_col_addr = 10
        edc_config = 0
        n_banks_per_sdram_device = 8
        tCKmin_X_ps = 1500
        tCKmin_X_minus_1_ps = 0
        tCKmin_X_minus_2_ps = 0
        tCKmax_ps = 0
        caslat_X = 960
        tAA_ps = 13125
        caslat_X_minus_1 = 0
        caslat_X_minus_2 = 0
        caslat_lowest_derated = 0
        tRCD_ps = 13125
        tRP_ps = 13125
        tRAS_ps = 36000
        tWR_ps = 15000
        tWTR_ps = 7500
        tRFC_ps = 160000
        tRRD_ps = 6000
        tRC_ps = 49125
        refresh_rate_ps = 7800000
        tIS_ps = 0
        tIH_ps = 0
        tDS_ps = 0
        tDH_ps = 0
        tRTP_ps = 7500
        tDQSQ_max_ps = 0
        tQHS_ps = 0
        FSL DDR>edit c0 opts ECC_mode 0
        FSL DDR>edit c0 regs cs0_bnds 0x000000FF
        FSL DDR>go
        2 GiB left unmapped
        4 GiB (DDR3, 64-bit, CL=9, ECC off)
               DDR Chip-Select Interleaving Mode: CS0+CS1
        Testing 0x00000000 - 0x7fffffff
        Testing 0x80000000 - 0xffffffff
        Remap DDR 2 GiB left unmapped

        POST memory PASSED
        Flash: 128 MiB
        L2:    128 KB enabled
        Corenet Platform Cache: 1024 KB enabled
        SERDES: timeout resetting bank 3
        SRIO1: disabled
        SRIO2: disabled
        MMC:  FSL_ESDHC: 0
        EEPROM: Invalid ID (ff ff ff ff)
        PCIe1: disabled
        PCIe2: Root Complex, x1, regs @ 0xfe201000
          01:00.0     - 8086:10d3 - Network controller
        PCIe2: Bus 00 - 01
        PCIe3: disabled
        In:    serial
        Out:   serial
        Err:   serial
        Net:   Initializing Fman
        Fman1: Uploading microcode version 101.8.0
        e1000: 00:1b:21:81:d2:e0
        FM1@DTSEC1, FM1@DTSEC2, FM1@DTSEC3, FM1@DTSEC4, FM1@DTSEC5, e1000#0 [PRIME]
        Warning: e1000#0 MAC addresses don't match:
        Address in SROM is         00:1b:21:81:d2:e0
        Address in environment is  00:e0:0c:00:ea:05

        Hit any key to stop autoboot:  0
        =>