[PATCH v5 2/9] doc: Add documentation for Coresight CPU debug

Leo Yan
2017-03-25T18:23:10Z

Update kernel-parameters.txt to add two new parameters:

- coresight_cpu_debug.enable is a knob to enable debugging at boot time.
- coresight_cpu_debug.idle_constraint is used to constrain idle states
to ensure Coresight CPU debug component can be accessible.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
---
Documentation/admin-guide/kernel-parameters.txt | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 2ba45ca..6ed57d9 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -650,6 +650,27 @@
/proc/<pid>/coredump_filter.
See also Documentation/filesystems/proc.txt.

+ coresight_cpu_debug.enable
+ [ARM,ARM64]
+ Format: <bool>
+ Enable/disable the CPU sampling based debugging.
+ 0: default value, disable debugging
+ 1: enable debugging at boot time
+
+ coresight_cpu_debug.idle_constraint
+ [ARM,ARM64]
+ Format: <int>
+ Some platforms have designed the idle states to disable
+ CPU power domain and need manually set constraint so
+ can access coresight CPU debug component safely. Setting
+ this parameter for latency requirement in
+ microseconds, finally we can constraint all or partial
+ idle states to ensure the CPU power domain is enabled.
+ Default is -1, which means no limiation to CPU idle
+ states; if set to 0, this means disabling all idle
+ states; user can choose other platform dependent values
+ so can disable specific idle states for the platform.
+
cpuidle.off=1 [CPU_IDLE]
disable the cpuidle sub-system

--
2.7.4