4 Andy Shevchenko <andriy.shevchenko@linux.intel.com>
6 This small document introduces how to test DMA drivers using dmatest module.
8 Part 1 - How to build the test module
10 The menuconfig contains an option that could be found by following path:
11 Device Drivers -> DMA Engine support -> DMA Test client
13 In the configuration file the option called CONFIG_DMATEST. The dmatest could
14 be built as module or inside kernel. Let's consider those cases.
16 Part 2 - When dmatest is built as a module...
19 % modprobe dmatest channel=dma0chan0 timeout=2000 iterations=1 run=1
23 % echo dma0chan0 > /sys/module/dmatest/parameters/channel
24 % echo 2000 > /sys/module/dmatest/parameters/timeout
25 % echo 1 > /sys/module/dmatest/parameters/iterations
26 % echo 1 > /sys/module/dmatest/parameters/run
28 ...or on the kernel command line:
30 dmatest.channel=dma0chan0 dmatest.timeout=2000 dmatest.iterations=1 dmatest.run=1
32 Hint: available channel list could be extracted by running the following
34 % ls -1 /sys/class/dma/
36 Once started a message like "dmatest: Started 1 threads using dma0chan0" is
37 emitted. After that only test failure messages are reported until the test
40 Note that running a new test will not stop any in progress test.
42 The following command should return actual state of the test.
43 % cat /sys/kernel/debug/dmatest/run
45 To wait for test done the user may perform a busy loop that checks the state.
47 % while [ $(cat /sys/module/dmatest/parameters/run) = "Y" ]
54 Part 3 - When built-in in the kernel...
56 The module parameters that is supplied to the kernel command line will be used
57 for the first performed test. After user gets a control, the test could be
58 re-run with the same or different parameters. For the details see the above
59 section "Part 2 - When dmatest is built as a module..."
61 In both cases the module parameters are used as the actual values for the test
62 case. You always could check them at run-time by running
63 % grep -H . /sys/module/dmatest/parameters/*
65 Part 4 - Gathering the test results
67 Test results are printed to the kernel log buffer with the format:
69 "dmatest: result <channel>: <test id>: '<error msg>' with src_off=<val> dst_off=<val> len=<val> (<err code>)"
73 dmatest: result dma0chan0-copy0: #1: No errors with src_off=0x7bf dst_off=0x8ad len=0x3fea (0)
75 The message format is unified across the different types of errors. A number in
76 the parens represents additional information, e.g. error code, error counter,
77 or status. A test thread also emits a summary line at completion listing the
78 number of tests executed, number that failed, and a result code.
82 dmatest: dma3chan0-copy0: summary 400000 tests, 0 failures iops: 61524 KB/s 246098 (0)
84 The details of a data miscompare error are also emitted, but do not follow the