Overview
  --------
  The T4240QDS is a high-performance computing evaluation, development and test
  platform supporting the T4240 QorIQ™ Power Architecture™ processor. T4240QDS is
  optimized to support the high-bandwidth DDR3 memory ports, as well as the
  highly-configurable SerDes ports. The system is lead-free and RoHS-compliant.
  
  Board Features
    SERDES Connections
  	32 lanes grouped into four 8-lane banks
  	Two “front side” banks dedicated to Ethernet
  		- High-speed crosspoint switch fabric on selected lanes
  		- Two PCI Express slots with side-band connector supporting
  		- SGMII
  		- XAUI
  		- HiGig
  		- I-pass connectors allow board-to-board and loopback support
  	Two “back side” banks dedicated to other protocols
  		- High-speed crosspoint switch fabric on all lanes
  		- Four PCI Express slots with side-band connector supporting
  		- PCI Express 3.0
  		- SATA 2.0
  		- SRIO 2.0
  		- Supports 4X Aurora debug with two connectors
    DDR Controllers
  	Three independant 64-bit DDR3 controllers
  	Supports rates of 1866 up to 2133 MHz data-rate
  	Supports two DDR3/DDR3LP UDIMM/RDIMMs per controller
  	DDR power supplies 1.5V to all devices with automatic tracking of VTT.
  	Power software-switchable to 1.35V if software detects all DDR3LP devices.
  	MT9JSF25672AZ-2G1KZESZF has been tested at 1333, 1600, 1867, 2000 and
  	2133MT/s speeds. For 1867MT/s and above, read-to-write turnaround time
  	increases by 1 clock.
  
    IFC/Local Bus
  	NAND flash: 8-bit, async or sync, up to 2GB.
  	NOR: 16-bit, Address/Data Multiplexed (ADM), up to 128 MB
  	NOR: 8-bit or 16-bit, non-multiplexed, up to 512MB
  		- NOR devices support 16 virtual banks
  	GASIC: Minimal target within Qixis FPGA
  	PromJET rapid memory download support
  	Address demultiplexing handled within FPGA.
  		- Flexible demux allows 8 or 16 bit evaluation.
  	IFC Debug/Development card
  		- Support for 32-bit devices
    Ethernet
  	Support two on-board RGMII 10/100/1G ethernet ports.
  	SGMII and XAUI support via SERDES block (see above).
  	1588 support via Symmetricom board.
    QIXIS System Logic FPGA
  	Manages system power and reset sequencing
  	Manages DUT, board, clock, etc. configuration for dynamic shmoo
  	Collects V-I-T data in background for code/power profiling.
  	Supports legacy TMT test features (POSt, IRS, SYSCLK-synchronous assertion)
  	General fault monitoring and logging
  	Runs from ATX “hot” power rails allowing operation while system is off.
    Clocks
  	System and DDR clock (SYSCLK, “DDRCLK”)
  		- Switch selectable to one of 16 common settings in the interval 33MHz-166MHz.
  		- Software selectable in 1MHz increments from 1-200MHz.
  	SERDES clocks
  		- Provides clocks to all SerDes blocks and slots
  		- 100, 125 and 156.25 MHz
    Power Supplies
  	Dedicated regulators for VDD
  		- Adjustable from (0.7V to 1.3V at 80A
  		- Regulators can be controlled by VID and/or software
  	Dedicated regulator for GVDD_PL: 1.35/1.5V at 22A
  		- VTT/MVREF automatically track operating voltage
  	Dedicated regulators/filters for AVDD supplies
  	Dedicated regulators for other supplies: OVDD, BVDD, DVDD, LVDD, POVDD, etc.
    USB
  	Supports two USB 2.0 ports with integrated PHYs
  		- One type A, one type micro-AB with 1.0A power per port.
    Other IO
  	eSDHC/MMC
  		- SDHC card slot
  	eSPI port
  		- High-speed serial flash
  	Two Serial port
  	Four I2C ports
  
  Memory map
  ----------
  The addresses in brackets are physical addresses.
  
  0x0_0000_0000 (0x0_0000_0000) - 0x0_7fff_ffff   2GB DDR (more than 2GB is initialized but not mapped under with TLB)
  0x0_8000_0000 (0xc_0000_0000) - 0x0_dfff_ffff 1.5GB PCIE memory

  0x0_f000_0000 (0xf_0000_0000) - 0x0_f1ff_ffff  32MB DCSR (includes trace buffers)

  0x0_f400_0000 (0xf_f400_0000) - 0x0_f5ff_ffff  32MB BMan
  0x0_f600_0000 (0xf_f600_0000) - 0x0_f7ff_ffff  32MB QMan
  0x0_f800_0000 (0xf_f800_0000) - 0x0_f803_ffff 256KB PCIE IO
  0x0_e000_0000 (0xf_e000_0000) - 0x0_efff_ffff 256MB NOR flash
  0x0_fe00_0000 (0xf_fe00_0000) - 0x0_feff_ffff  16MB CCSR
  0x0_ffdf_0000 (0xf_ffdf_0000) - 0x0_ffdf_03ff   4KB QIXIS
  0x0_ffff_f000 (0x0_7fff_fff0) - 0x0_ffff_ffff   4KB Boot page translation for secondary cores
  
  The physical address of the last (boot page translation) varies with the actual DDR size.

  
  Voltage ID and VDD override
  --------------------
  T4240 has a VID feature. U-boot reads the VID efuses and adjust the voltage
  accordingly. The voltage can also be override by command vdd_override. The
  syntax is
  
  vdd_override <voltage in mV>, eg. 1050 is for 1.050v.
  
  Upon success, the actual voltage will be read back. The value is checked
  for safety and any invalid value will not adjust the voltage.
  
  Another way to override VDD is to use environmental variable, in case of using
  command is too late for some debugging. The syntax is
  
  setenv t4240qds_vdd_mv <voltage in mV>
  saveenv
  reset
  
  The override voltage takes effect when booting.
  
  Note: voltage adjustment needs to be done step by step. Changing voltage too
  rapidly may cause current surge. The voltage stepping is done by software.
  Users can set the final voltage directly.