summaryrefslogtreecommitdiff
path: root/Documentation/driver-api
diff options
context:
space:
mode:
authorVinod Koul <vinod.koul@intel.com>2017-11-03 07:49:40 +0300
committerJonathan Corbet <corbet@lwn.net>2017-11-05 20:03:30 +0300
commit179a214e9e985ef9b14d7e5d9fff20acddb9315b (patch)
tree43da0157a9f45921ba4123eadd3409b71e4151fa /Documentation/driver-api
parenteeb1c6435293e9d3c30b21579bd5154c013f2843 (diff)
downloadlinux-179a214e9e985ef9b14d7e5d9fff20acddb9315b.tar.xz
dmaengine: doc: ReSTize dmatest doc
This converts and moves dmatest file with some format changes for RST style Signed-off-by: Vinod Koul <vinod.koul@intel.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Diffstat (limited to 'Documentation/driver-api')
-rw-r--r--Documentation/driver-api/dmaengine/dmatest.rst110
-rw-r--r--Documentation/driver-api/dmaengine/index.rst10
2 files changed, 120 insertions, 0 deletions
diff --git a/Documentation/driver-api/dmaengine/dmatest.rst b/Documentation/driver-api/dmaengine/dmatest.rst
new file mode 100644
index 000000000000..3922c0a3f0c0
--- /dev/null
+++ b/Documentation/driver-api/dmaengine/dmatest.rst
@@ -0,0 +1,110 @@
+==============
+DMA Test Guide
+==============
+
+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
+=====================================
+
+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
+==========================================
+
+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/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/
+
+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 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
+====================================
+
+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
+re-run with the same or different parameters. For the details see the above
+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/*
+
+Part 4 - Gathering the test results
+===================================
+
+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>)"
+
+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)
+
+The details of a data miscompare error are also emitted, but do not follow the
+above format.
diff --git a/Documentation/driver-api/dmaengine/index.rst b/Documentation/driver-api/dmaengine/index.rst
index ffc2b797938c..fae852922a49 100644
--- a/Documentation/driver-api/dmaengine/index.rst
+++ b/Documentation/driver-api/dmaengine/index.rst
@@ -27,6 +27,16 @@ API of the DMAEngine. This is applicable only for slave DMA usage only.
client
+DMA Test documentation
+----------------------
+
+This book introduces how to test DMA drivers using dmatest module.
+
+.. toctree::
+ :maxdepth: 1
+
+ dmatest
+
.. only:: subproject
Indices