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Diffstat (limited to 'Documentation/dmatest.txt')
| -rw-r--r-- | Documentation/dmatest.txt | 72 |
1 files changed, 41 insertions, 31 deletions
diff --git a/Documentation/dmatest.txt b/Documentation/dmatest.txt index a2b5663eae26..dd77a81bdb80 100644 --- a/Documentation/dmatest.txt +++ b/Documentation/dmatest.txt @@ -15,39 +15,48 @@ be built as module or inside kernel. Let's consider those cases. Part 2 - 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. There are two important files located. First -is the 'run' node that controls run and stop phases of the test, and the second -one, 'results', is used to get the test case results. - -Note that in this case test will not run on load automatically. - Example of usage: + % modprobe dmatest channel=dma0chan0 timeout=2000 iterations=1 run=1 + +...or: + % modprobe dmatest % echo dma0chan0 > /sys/module/dmatest/parameters/channel % echo 2000 > /sys/module/dmatest/parameters/timeout % echo 1 > /sys/module/dmatest/parameters/iterations - % echo 1 > /sys/kernel/debug/dmatest/run + % echo 1 > /sys/module/dmatest/parameters/run + +...or on the kernel command line: + + dmatest.channel=dma0chan0 dmatest.timeout=2000 dmatest.iterations=1 dmatest.run=1 Hint: available channel list could be extracted by running the following command: % ls -1 /sys/class/dma/ -After a while you will start to get messages about current status or error like -in the original code. +Once started a message like "dmatest: Started 1 threads using dma0chan0" is +emitted. After that only test failure messages are reported until the test +stops. Note that running a new test will not stop any in progress test. -The following command should return actual state of the test. - % cat /sys/kernel/debug/dmatest/run - -To wait for test done the user may perform a busy loop that checks the state. - - % while [ $(cat /sys/kernel/debug/dmatest/run) = "Y" ] - > do - > echo -n "." - > sleep 1 - > done - > echo +The following command returns the state of the test. + % cat /sys/module/dmatest/parameters/run + +To wait for test completion userpace can poll 'run' until it is false, or use +the wait parameter. Specifying 'wait=1' when loading the module causes module +initialization to pause until a test run has completed, while reading +/sys/module/dmatest/parameters/wait waits for any running test to complete +before returning. For example, the following scripts wait for 42 tests +to complete before exiting. Note that if 'iterations' is set to 'infinite' then +waiting is disabled. + +Example: + % modprobe dmatest run=1 iterations=42 wait=1 + % modprobe -r dmatest +...or: + % modprobe dmatest run=1 iterations=42 + % cat /sys/module/dmatest/parameters/wait + % modprobe -r dmatest Part 3 - When built-in in the kernel... @@ -62,21 +71,22 @@ case. You always could check them at run-time by running Part 4 - Gathering the test results -The module provides a storage for the test results in the memory. The gathered -data could be used after test is done. +Test results are printed to the kernel log buffer with the format: -The special file 'results' in the debugfs represents gathered data of the in -progress test. The messages collected are printed to the kernel log as well. +"dmatest: result <channel>: <test id>: '<error msg>' with src_off=<val> dst_off=<val> len=<val> (<err code>)" Example of output: - % cat /sys/kernel/debug/dmatest/results - dma0chan0-copy0: #1: No errors with src_off=0x7bf dst_off=0x8ad len=0x3fea (0) + % dmesg | tail -n 1 + dmatest: result dma0chan0-copy0: #1: No errors with src_off=0x7bf dst_off=0x8ad len=0x3fea (0) The message format is unified across the different types of errors. A number in the parens represents additional information, e.g. error code, error counter, -or status. +or status. A test thread also emits a summary line at completion listing the +number of tests executed, number that failed, and a result code. -Comparison between buffers is stored to the dedicated structure. +Example: + % dmesg | tail -n 1 + dmatest: dma0chan0-copy0: summary 1 test, 0 failures 1000 iops 100000 KB/s (0) -Note that the verify result is now accessible only via file 'results' in the -debugfs. +The details of a data miscompare error are also emitted, but do not follow the +above format. |