• York Sun's avatar
    powerpc/8xxx: Add support for interactive DDR programming interface · 6f5e1dc5
    York Sun authored
    
    
    Interactive DDR debugging provides a user interface to view and modify SPD,
    DIMM parameters, board options and DDR controller registers before DDR is
    initialized. With this feature, developers can fine-tune DDR for board
    bringup and other debugging without frequently having to reprogram the flash.
    
    To enable this feature, define CONFIG_FSL_DDR_INTERACTIVE in board header
    file and set an environment variable to activate it. Syntax:
    
    setenv ddr_interactive on
    
    After reset, U-boot prompts before initializing DDR controllers
    FSL DDR>
    
    The available commands are
    print      print SPD and intermediate computed data
    reset      reboot machine
    recompute  reload SPD and options to default and recompute regs
    edit       modify spd, parameter, or option
    compute    recompute registers from current next_step to end
    next_step  shows current next_step
    help       this message
    go         program the memory controller and continue with u-boot
    
    The first command should be "compute", which reads data from DIMM SPDs and
    board options, performs the calculation then stops before setting DDR
    controller. A user can use "print" and "edit" commands to view and modify
    anything. "Go" picks up from current step with any modification and
    compltes the calculation then enables the DDR controller to continue u-boot.
    "Recompute" does it over from fresh reading.
    Signed-off-by: default avatarYork Sun <yorksun@freescale.com>
    Signed-off-by: default avatarKumar Gala <galak@kernel.crashing.org>
    6f5e1dc5
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