mirror of
https://github.com/FEX-Emu/linux.git
synced 2024-12-24 02:18:54 +00:00
d86b2f298e
Comparison between buffers is stored to the dedicated structure. Note that the verify result is now accessible only via file 'results' in the debugfs. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
82 lines
2.8 KiB
Plaintext
82 lines
2.8 KiB
Plaintext
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...
|
|
|
|
After mounting debugfs and loading the module, the /sys/kernel/debug/dmatest
|
|
folder with nodes will be created. They are the same as module parameters with
|
|
addition of the 'run' node that controls run and stop phases of the test.
|
|
|
|
Note that in this case test will not run on load automatically.
|
|
|
|
Example of usage:
|
|
% echo dma0chan0 > /sys/kernel/debug/dmatest/channel
|
|
% echo 2000 > /sys/kernel/debug/dmatest/timeout
|
|
% echo 1 > /sys/kernel/debug/dmatest/iterations
|
|
% echo 1 > /sys/kernel/debug/dmatest/run
|
|
|
|
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.
|
|
|
|
Note that running a new test will 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
|
|
|
|
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
|
|
interrupted or re-run with 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 initial 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
|
|
|
|
The module provides a storage for the test results in the memory. The gathered
|
|
data could be used after test is done.
|
|
|
|
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.
|
|
|
|
Example of output:
|
|
% cat /sys/kernel/debug/dmatest/results
|
|
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.
|
|
|
|
Comparison between buffers is stored to the dedicated structure.
|
|
|
|
Note that the verify result is now accessible only via file 'results' in the
|
|
debugfs.
|