5 Andy Shevchenko <andriy.shevchenko@linux.intel.com>
7 This small document introduces how to test DMA drivers using dmatest module.
10 The test suite works only on the channels that have at least one
11 capability of the following: DMA_MEMCPY (memory-to-memory), DMA_MEMSET
12 (const-to-memory or memory-to-memory, when emulated), DMA_XOR, DMA_PQ.
15 In case of any related questions use the official mailing list
16 dmaengine@vger.kernel.org.
18 Part 1 - How to build the test module
19 =====================================
21 The menuconfig contains an option that could be found by following path:
23 Device Drivers -> DMA Engine support -> DMA Test client
25 In the configuration file the option called CONFIG_DMATEST. The dmatest could
26 be built as module or inside kernel. Let's consider those cases.
28 Part 2 - When dmatest is built as a module
29 ==========================================
33 % modprobe dmatest timeout=2000 iterations=1 channel=dma0chan0 run=1
38 % echo 2000 > /sys/module/dmatest/parameters/timeout
39 % echo 1 > /sys/module/dmatest/parameters/iterations
40 % echo dma0chan0 > /sys/module/dmatest/parameters/channel
41 % echo 1 > /sys/module/dmatest/parameters/run
43 ...or on the kernel command line::
45 dmatest.timeout=2000 dmatest.iterations=1 dmatest.channel=dma0chan0 dmatest.run=1
47 Example of multi-channel test usage:
49 % echo 2000 > /sys/module/dmatest/parameters/timeout
50 % echo 1 > /sys/module/dmatest/parameters/iterations
51 % echo dma0chan0 > /sys/module/dmatest/parameters/channel
52 % echo dma0chan1 > /sys/module/dmatest/parameters/channel
53 % echo dma0chan2 > /sys/module/dmatest/parameters/channel
54 % echo 1 > /sys/module/dmatest/parameters/run
56 Note: the channel parameter should always be the last parameter set prior to
57 running the test (setting run=1), this is because upon setting the channel
58 parameter, that specific channel is requested using the dmaengine and a thread
59 is created with the existing parameters. This thread is set as pending
60 and will be executed once run is set to 1. Any parameters set after the thread
61 is created are not applied.
63 available channel list could be extracted by running the following command::
65 % ls -1 /sys/class/dma/
67 Once started a message like " dmatest: Added 1 threads using dma0chan0" is
68 emitted. A thread for that specific channel is created and is now pending, the
69 pending thread is started once run is to 1.
71 Note that running a new test will not stop any in progress test.
73 The following command returns the state of the test. ::
75 % cat /sys/module/dmatest/parameters/run
77 To wait for test completion userpace can poll 'run' until it is false, or use
78 the wait parameter. Specifying 'wait=1' when loading the module causes module
79 initialization to pause until a test run has completed, while reading
80 /sys/module/dmatest/parameters/wait waits for any running test to complete
81 before returning. For example, the following scripts wait for 42 tests
82 to complete before exiting. Note that if 'iterations' is set to 'infinite' then
87 % modprobe dmatest run=1 iterations=42 wait=1
92 % modprobe dmatest run=1 iterations=42
93 % cat /sys/module/dmatest/parameters/wait
96 Part 3 - When built-in in the kernel
97 ====================================
99 The module parameters that is supplied to the kernel command line will be used
100 for the first performed test. After user gets a control, the test could be
101 re-run with the same or different parameters. For the details see the above
102 section `Part 2 - When dmatest is built as a module`_.
104 In both cases the module parameters are used as the actual values for the test
105 case. You always could check them at run-time by running ::
107 % grep -H . /sys/module/dmatest/parameters/*
109 Part 4 - Gathering the test results
110 ===================================
112 Test results are printed to the kernel log buffer with the format::
114 "dmatest: result <channel>: <test id>: '<error msg>' with src_off=<val> dst_off=<val> len=<val> (<err code>)"
119 dmatest: result dma0chan0-copy0: #1: No errors with src_off=0x7bf dst_off=0x8ad len=0x3fea (0)
121 The message format is unified across the different types of errors. A
122 number in the parentheses represents additional information, e.g. error
123 code, error counter, or status. A test thread also emits a summary line at
124 completion listing the number of tests executed, number that failed, and a
130 dmatest: dma0chan0-copy0: summary 1 test, 0 failures 1000 iops 100000 KB/s (0)
132 The details of a data miscompare error are also emitted, but do not follow the
135 Part 5 - Handling channel allocation
136 ====================================
141 Channels are required to be configured prior to starting the test run.
142 Attempting to run the test without configuring the channels will fail.
146 % echo 1 > /sys/module/dmatest/parameters/run
147 dmatest: Could not start test, no channels configured
149 Channels are registered using the "channel" parameter. Channels can be requested by their
150 name, once requested, the channel is registered and a pending thread is added to the test list.
154 % echo dma0chan2 > /sys/module/dmatest/parameters/channel
155 dmatest: Added 1 threads using dma0chan2
157 More channels can be added by repeating the example above.
158 Reading back the channel parameter will return the name of last channel that was added successfully.
162 % echo dma0chan1 > /sys/module/dmatest/parameters/channel
163 dmatest: Added 1 threads using dma0chan1
164 % echo dma0chan2 > /sys/module/dmatest/parameters/channel
165 dmatest: Added 1 threads using dma0chan2
166 % cat /sys/module/dmatest/parameters/channel
169 Another method of requesting channels is to request a channel with an empty string, Doing so
170 will request all channels available to be tested:
174 % echo "" > /sys/module/dmatest/parameters/channel
175 dmatest: Added 1 threads using dma0chan0
176 dmatest: Added 1 threads using dma0chan3
177 dmatest: Added 1 threads using dma0chan4
178 dmatest: Added 1 threads using dma0chan5
179 dmatest: Added 1 threads using dma0chan6
180 dmatest: Added 1 threads using dma0chan7
181 dmatest: Added 1 threads using dma0chan8
183 At any point during the test configuration, reading the "test_list" parameter will
184 print the list of currently pending tests.
188 % cat /sys/module/dmatest/parameters/test_list
189 dmatest: 1 threads using dma0chan0
190 dmatest: 1 threads using dma0chan3
191 dmatest: 1 threads using dma0chan4
192 dmatest: 1 threads using dma0chan5
193 dmatest: 1 threads using dma0chan6
194 dmatest: 1 threads using dma0chan7
195 dmatest: 1 threads using dma0chan8
197 Note: Channels will have to be configured for each test run as channel configurations do not
198 carry across to the next test run.
203 Channels can be freed by setting run to 0.
206 % echo dma0chan1 > /sys/module/dmatest/parameters/channel
207 dmatest: Added 1 threads using dma0chan1
208 % cat /sys/class/dma/dma0chan1/in_use
210 % echo 0 > /sys/module/dmatest/parameters/run
211 % cat /sys/class/dma/dma0chan1/in_use
214 Channels allocated by previous test runs are automatically freed when a new
215 channel is requested after completing a successful test run.