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Commit 179a214e authored by Vinod Koul's avatar Vinod Koul Committed by Jonathan Corbet
Browse files

dmaengine: doc: ReSTize dmatest doc 



This converts and moves dmatest file with some format
changes for RST style

Signed-off-by: default avatarVinod Koul <vinod.koul@intel.com>
Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
parent eeb1c643

Documentation/dmaengine/dmatest.txt→Documentation/driver-api/dmaengine/dmatest.rst

+57 −39
Original line number Diff line number Diff line 
==============

DMA Test Guide

==============
@@ -6,6 +7,7 @@ 
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
@@ -13,24 +15,30 @@ The menuconfig contains an option that could be found by following path: 
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: ::



Example of usage:

    % modprobe dmatest channel=dma0chan0 timeout=2000 iterations=1 run=1



...or:

...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:

...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

..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
@@ -39,7 +47,8 @@ stops. 


Note that running a new test will not stop any in progress test.



The following command returns the state of the 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
@@ -50,15 +59,19 @@ 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:

Example: ::



    % modprobe dmatest run=1 iterations=42 wait=1

    % modprobe -r dmatest

...or:



...or: ::



    % modprobe dmatest run=1 iterations=42

    % cat /sys/module/dmatest/parameters/wait

    % modprobe -r dmatest



	Part 3 - When built-in in the kernel...

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
@@ -66,16 +79,20 @@ 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

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:

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:

Example of output: ::





    % dmesg | tail -n 1

    dmatest: result dma0chan0-copy0: #1: No errors with src_off=0x7bf dst_off=0x8ad len=0x3fea (0)
@@ -84,7 +101,8 @@ 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:

Example: ::



    % dmesg | tail -n 1

    dmatest: dma0chan0-copy0: summary 1 test, 0 failures 1000 iops 100000 KB/s (0)

Documentation/driver-api/dmaengine/index.rst

+10 −0
Original line number Diff line number Diff line
@@ -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