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  • Andy Shevchenko's avatar
    dmatest: run test via debugfs · 851b7e16
    Andy Shevchenko authored
    
    
    Instead of doing
    	modprobe dmatest ...
    	modprobe -r dmatest
    we allow user to run tests interactively.
    
    The dmatest could be built as module or inside kernel. Let's consider those
    cases.
    
    1. When dmatest is built as a module...
    
    After mounting debugfs and loading the module, the /sys/kernel/debug/dmatest
    folder with nodes will be created. They are the same as module parameters with
    addition of the 'run' node that controls run and stop phases of the test.
    
    Note that in this case test will not run on load automatically.
    
    Example of usage:
    	% echo dma0chan0 > /sys/kernel/debug/dmatest/channel
    	% echo 2000 > /sys/kernel/debug/dmatest/timeout
    	% echo 1 > /sys/kernel/debug/dmatest/iterations
    	% echo 1 > /sys/kernel/debug/dmatest/run
    
    After a while you will start to get messages about current status or error like
    in the original code.
    
    Note that running a new test will stop any in progress test.
    
    2. When built-in in the kernel...
    
    The module parameters that is supplied to the kernel command line will be used
    for the first performed test. After user gets a control, the test could be
    interrupted or re-run with same or different parameters. For the details see
    the above section "1. When dmatest is built as a module..."
    
    In both cases the module parameters are used as initial values for the test case.
    You always could check them at run-time by running
    	% grep -H . /sys/module/dmatest/parameters/*
    
    Signed-off-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
    Signed-off-by: default avatarVinod Koul <vinod.koul@intel.com>
    851b7e16