Eric Lee / smarc-fsl-linux-kernel

05 Sep, 2020

1 commit

  • 51fae39bd   scripts/dev-needs: Add script to list device dependencies ... Browse Code ยป

    This script can be useful for:
    - Figuring out the list of modules you need to pack in initrd
    - Figuring out the list of drivers you need to modularize for a device
    to be fully functional without building in any dependencies.
    - Figuring out which drivers to enable first, when porting drivers
    between kernels (say, to upstream).
    - Plotting graphs of system dependencies, etc.

    Usage: dev-needs.sh [-c|-d|-m|-f] [filter options]

    This script needs to be run on the target device once it has booted to a
    shell.

    The script takes as input a list of one or more device directories under
    /sys/devices and then lists the probe dependency chain (suppliers and
    parents) of these devices. It does a breadth first search of the dependency
    chain, so the last entry in the output is close to the root of the
    dependency chain.

    By default it lists the full path to the devices under /sys/devices.

    It also takes an optional modifier flag as the first parameter to change
    what information is listed in the output. If the requested information is
    not available, the device name is printed.

    -c lists the compatible string of the dependencies
    -d lists the driver name of the dependencies that have probed
    -m lists the module name of the dependencies that have a module
    -f list the firmware node path of the dependencies
    -g list the dependencies as edges and nodes for graphviz
    -t list the dependencies as edges for tsort

    The filter options provide a way to filter out some dependencies:
    --allow-no-driver By default dependencies that don't have a driver
    attached are ignored. This is to avoid following
    device links to "class" devices that are created
    when the consumer probes (as in, not a probe
    dependency). If you want to follow these links
    anyway, use this flag.

    --exclude-devlinks Don't follow device links when tracking probe
    dependencies.

    --exclude-parents Don't follow parent devices when tracking probe
    dependencies.

    Signed-off-by: Saravana Kannan
    Link: https://lore.kernel.org/r/20200901224842.1787825-1-saravanak@google.com
    Signed-off-by: Greg Kroah-Hartman

    Saravana Kannan