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authorLinus Torvalds2019-01-01 15:45:48 -0800
committerLinus Torvalds2019-01-01 15:45:48 -0800
commit78e8696c234ab637c4dd516cabeac344d84ec10b (patch)
tree95b553e6d5640ad52cf86986e009e7eef86f916e /Documentation/driver-api
parentfcf010449ebe1db0cb68b2c6410972a782f2bd14 (diff)
parent660611827c03afeb0eec178dc1fb9f842332d908 (diff)
Merge tag 'dmaengine-4.21-rc1' of git://git.infradead.org/users/vkoul/slave-dma
Pull dmaengine updates from Vinod Koul: "This includes a new driver, removes R-Mobile APE6 as it is no longer used, sprd cyclic dma support, last batch of dma_slave_config direction removal and random updates to bunch of drivers. Summary: - New driver for UniPhier MIO DMA controller - Remove R-Mobile APE6 support - Sprd driver updates and support for cyclic link-list - Remove dma_slave_config direction usage from rest of drivers - Minor updates to dmatest, dw-dmac, zynqmp and bcm dma drivers" * tag 'dmaengine-4.21-rc1' of git://git.infradead.org/users/vkoul/slave-dma: (48 commits) dmaengine: qcom_hidma: convert to DEFINE_SHOW_ATTRIBUTE dmaengine: pxa: remove DBGFS_FUNC_DECL() dmaengine: mic_x100_dma: convert to DEFINE_SHOW_ATTRIBUTE dmaengine: amba-pl08x: convert to DEFINE_SHOW_ATTRIBUTE dmaengine: Documentation: Add documentation for multi chan testing dmaengine: dmatest: Add transfer_size parameter dmaengine: dmatest: Add alignment parameter dmaengine: dmatest: Use fixed point div to calculate iops dmaengine: dmatest: Add support for multi channel testing dmaengine: rcar-dmac: Document R8A774C0 bindings dt-bindings: dmaengine: usb-dmac: Add binding for r8a774c0 dmaengine: zynqmp_dma: replace spin_lock_bh with spin_lock_irqsave dmaengine: sprd: Add me as one of the module authors dmaengine: sprd: Support DMA 2-stage transfer mode dmaengine: sprd: Support DMA link-list cyclic callback dmaengine: sprd: Set cur_desc as NULL when free or terminate one dma channel dmaengine: sprd: Fix the last link-list configuration dmaengine: sprd: Get transfer residue depending on the transfer direction dmaengine: sprd: Remove direction usage from struct dma_slave_config dmaengine: dmatest: fix a small memory leak in dmatest_func() ...
Diffstat (limited to 'Documentation/driver-api')
-rw-r--r--Documentation/driver-api/dmaengine/dmatest.rst109
1 files changed, 103 insertions, 6 deletions
diff --git a/Documentation/driver-api/dmaengine/dmatest.rst b/Documentation/driver-api/dmaengine/dmatest.rst
index 49efebd2c043..8d81f1a7169b 100644
--- a/Documentation/driver-api/dmaengine/dmatest.rst
+++ b/Documentation/driver-api/dmaengine/dmatest.rst
@@ -30,28 +30,43 @@ Part 2 - When dmatest is built as a module
Example of usage::
- % modprobe dmatest channel=dma0chan0 timeout=2000 iterations=1 run=1
+ % modprobe dmatest timeout=2000 iterations=1 channel=dma0chan0 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 dma0chan0 > /sys/module/dmatest/parameters/channel
% 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
+ dmatest.timeout=2000 dmatest.iterations=1 dmatest.channel=dma0chan0 dmatest.run=1
+
+Example of multi-channel test usage:
+ % modprobe dmatest
+ % echo 2000 > /sys/module/dmatest/parameters/timeout
+ % echo 1 > /sys/module/dmatest/parameters/iterations
+ % echo dma0chan0 > /sys/module/dmatest/parameters/channel
+ % echo dma0chan1 > /sys/module/dmatest/parameters/channel
+ % echo dma0chan2 > /sys/module/dmatest/parameters/channel
+ % echo 1 > /sys/module/dmatest/parameters/run
+Note: the channel parameter should always be the last parameter set prior to
+running the test (setting run=1), this is because upon setting the channel
+parameter, that specific channel is requested using the dmaengine and a thread
+is created with the existing parameters. This thread is set as pending
+and will be executed once run is set to 1. Any parameters set after the thread
+is created are not applied.
.. 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.
+Once started a message like " dmatest: Added 1 threads using dma0chan0" is
+emitted. A thread for that specific channel is created and is now pending, the
+pending thread is started once run is to 1.
Note that running a new test will not stop any in progress test.
@@ -116,3 +131,85 @@ Example::
The details of a data miscompare error are also emitted, but do not follow the
above format.
+
+Part 5 - Handling channel allocation
+====================================
+
+Allocating Channels
+-------------------
+
+Channels are required to be configured prior to starting the test run.
+Attempting to run the test without configuring the channels will fail.
+
+Example::
+
+ % echo 1 > /sys/module/dmatest/parameters/run
+ dmatest: Could not start test, no channels configured
+
+Channels are registered using the "channel" parameter. Channels can be requested by their
+name, once requested, the channel is registered and a pending thread is added to the test list.
+
+Example::
+
+ % echo dma0chan2 > /sys/module/dmatest/parameters/channel
+ dmatest: Added 1 threads using dma0chan2
+
+More channels can be added by repeating the example above.
+Reading back the channel parameter will return the name of last channel that was added successfully.
+
+Example::
+
+ % echo dma0chan1 > /sys/module/dmatest/parameters/channel
+ dmatest: Added 1 threads using dma0chan1
+ % echo dma0chan2 > /sys/module/dmatest/parameters/channel
+ dmatest: Added 1 threads using dma0chan2
+ % cat /sys/module/dmatest/parameters/channel
+ dma0chan2
+
+Another method of requesting channels is to request a channel with an empty string, Doing so
+will request all channels available to be tested:
+
+Example::
+
+ % echo "" > /sys/module/dmatest/parameters/channel
+ dmatest: Added 1 threads using dma0chan0
+ dmatest: Added 1 threads using dma0chan3
+ dmatest: Added 1 threads using dma0chan4
+ dmatest: Added 1 threads using dma0chan5
+ dmatest: Added 1 threads using dma0chan6
+ dmatest: Added 1 threads using dma0chan7
+ dmatest: Added 1 threads using dma0chan8
+
+At any point during the test configuration, reading the "test_list" parameter will
+print the list of currently pending tests.
+
+Example::
+
+ % cat /sys/module/dmatest/parameters/test_list
+ dmatest: 1 threads using dma0chan0
+ dmatest: 1 threads using dma0chan3
+ dmatest: 1 threads using dma0chan4
+ dmatest: 1 threads using dma0chan5
+ dmatest: 1 threads using dma0chan6
+ dmatest: 1 threads using dma0chan7
+ dmatest: 1 threads using dma0chan8
+
+Note: Channels will have to be configured for each test run as channel configurations do not
+carry across to the next test run.
+
+Releasing Channels
+-------------------
+
+Channels can be freed by setting run to 0.
+
+Example::
+ % echo dma0chan1 > /sys/module/dmatest/parameters/channel
+ dmatest: Added 1 threads using dma0chan1
+ % cat /sys/class/dma/dma0chan1/in_use
+ 1
+ % echo 0 > /sys/module/dmatest/parameters/run
+ % cat /sys/class/dma/dma0chan1/in_use
+ 0
+
+Channels allocated by previous test runs are automatically freed when a new
+channel is requested after completing a successful test run.