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authorAlexander Shishkin <alexander.shishkin@linux.intel.com>2016-09-26 15:27:05 +0300
committerAlexander Shishkin <alexander.shishkin@linux.intel.com>2016-11-18 17:06:34 +0200
commitb29f6d3e59a1ff8dd5c0aeae8594801a15efcc2c (patch)
tree574216bbb03ac15f6eeea57d7b79959f419086a1 /Documentation/trace
parentbd566189723d919e6081b494856337ef61a23f9f (diff)
downloadlinux-b29f6d3e59a1ff8dd5c0aeae8594801a15efcc2c.tar.bz2
stm class: Document stm_source channel assignment
This patch adds an explanation of how and when stm_source devices are assigned STP masters and channels. Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Diffstat (limited to 'Documentation/trace')
-rw-r--r--Documentation/trace/stm.txt10
1 files changed, 10 insertions, 0 deletions
diff --git a/Documentation/trace/stm.txt b/Documentation/trace/stm.txt
index 349869851463..11cff47eecce 100644
--- a/Documentation/trace/stm.txt
+++ b/Documentation/trace/stm.txt
@@ -85,6 +85,16 @@ $ echo dummy_stm.0 > /sys/class/stm_source/console/stm_source_link
For examples on how to use stm_source interface in the kernel, refer
to stm_console or stm_heartbeat drivers.
+Each stm_source device will need to assume a master and a range of
+channels, depending on how many channels it requires. These are
+allocated for the device according to the policy configuration. If
+there's a node in the root of the policy directory that matches the
+stm_source device's name (for example, "console"), this node will be
+used to allocate master and channel numbers. If there's no such policy
+node, the stm core will pick the first contiguous chunk of channels
+within the first available master. Note that the node must exist
+before the stm_source device is connected to its stm device.
+
stm_console
===========