- DMA Test Guide
- ==============
+==============
+DMA Test Guide
+==============
- Andy Shevchenko <andriy.shevchenko@linux.intel.com>
+Andy Shevchenko <andriy.shevchenko@linux.intel.com>
This small document introduces how to test DMA drivers using dmatest module.
- Part 1 - How to build the test module
+Part 1 - How to build the test module
+=====================================
The menuconfig contains an option that could be found by following path:
Device Drivers -> DMA Engine support -> DMA Test client
In the configuration file the option called CONFIG_DMATEST. The dmatest could
be built as module or inside kernel. Let's consider those cases.
- Part 2 - When dmatest is built as a module...
+Part 2 - When dmatest is built as a module
+==========================================
-Example of usage:
- % modprobe dmatest channel=dma0chan0 timeout=2000 iterations=1 run=1
+Example of usage: ::
-...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/module/dmatest/parameters/run
+ % modprobe dmatest channel=dma0chan0 timeout=2000 iterations=1 run=1
-...or on the kernel command line:
+...or: ::
- dmatest.channel=dma0chan0 dmatest.timeout=2000 dmatest.iterations=1 dmatest.run=1
+ % 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/module/dmatest/parameters/run
-Hint: available channel list could be extracted by running the following
-command:
- % ls -1 /sys/class/dma/
+...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/
Once started a message like "dmatest: Started 1 threads using dma0chan0" is
emitted. After that only test failure messages are reported until the test
Note that running a new test will not stop any in progress test.
-The following command returns the state of the test.
- % cat /sys/module/dmatest/parameters/run
+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
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
+Example: ::
+
+ % modprobe dmatest run=1 iterations=42 wait=1
+ % modprobe -r dmatest
- Part 3 - When built-in in the kernel...
+...or: ::
+
+ % modprobe dmatest run=1 iterations=42
+ % cat /sys/module/dmatest/parameters/wait
+ % modprobe -r dmatest
+
+Part 3 - 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
section "Part 2 - When dmatest is built as a module..."
In both cases the module parameters are used as the actual values for the test
-case. You always could check them at run-time by running
- % grep -H . /sys/module/dmatest/parameters/*
+case. You always could check them at run-time by running ::
+
+ % grep -H . /sys/module/dmatest/parameters/*
- Part 4 - Gathering the test results
+Part 4 - Gathering the test results
+===================================
-Test results are printed to the kernel log buffer with the format:
+Test results are printed to the kernel log buffer with the format: ::
-"dmatest: result <channel>: <test id>: '<error msg>' with src_off=<val> dst_off=<val> len=<val> (<err code>)"
+ "dmatest: result <channel>: <test id>: '<error msg>' with src_off=<val> dst_off=<val> len=<val> (<err code>)"
-Example of output:
- % dmesg | tail -n 1
- dmatest: result dma0chan0-copy0: #1: No errors with src_off=0x7bf dst_off=0x8ad len=0x3fea (0)
+Example of output: ::
+
+
+ % 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. A test thread also emits a summary line at completion listing the
number of tests executed, number that failed, and a result code.
-Example:
- % dmesg | tail -n 1
- dmatest: dma0chan0-copy0: summary 1 test, 0 failures 1000 iops 100000 KB/s (0)
+Example: ::
+
+ % dmesg | tail -n 1
+ dmatest: dma0chan0-copy0: summary 1 test, 0 failures 1000 iops 100000 KB/s (0)
The details of a data miscompare error are also emitted, but do not follow the
above format.