linux-toradex.git/drivers/base/power/opp, branch v4.12

PM / OPP: fix off-by-one bug in dev_pm_opp_get_max_volt_latency loop

2017-02-23T22:00:31+00:00

Reading array at given index before checking if index is valid results in
illegal memory access.

The bug was detected using KASAN framework.

Signed-off-by: Andrzej Hajda 
Acked-by: Viresh Kumar 
Signed-off-by: Rafael J. Wysocki

PM / OPP: Expose _of_get_opp_desc_node as dev_pm_opp API

2017-02-09T21:52:17+00:00

Rename _of_get_opp_desc_node to dev_pm_opp_of_get_opp_desc_node and add it
to include/linux/pm_opp.h to allow other drivers, such as platform OPP
and cpufreq drivers, to make use of it.

Acked-by: Viresh Kumar 
Signed-off-by: Dave Gerlach 
Signed-off-by: Rafael J. Wysocki

PM / OPP: Make _find_opp_table_unlocked() static

2017-02-07T12:39:25+00:00

Fixes the following sparse warning:

drivers/base/power/opp/core.c:49:18: warning:
 symbol '_find_opp_table_unlocked' was not declared. Should it be static?

Signed-off-by: Wei Yongjun 
Reviewed-by: Stephen Boyd 
Acked-by: Viresh Kumar 
Signed-off-by: Rafael J. Wysocki

PM / OPP: Simplify dev_pm_opp_get_max_volt_latency()

2017-01-30T08:22:22+00:00

dev_pm_opp_get_max_volt_latency() calls _find_opp_table() two times
effectively.

Merge _get_regulator_count() into dev_pm_opp_get_max_volt_latency() to
avoid that.

Signed-off-by: Viresh Kumar 
Reviewed-by: Stephen Boyd 
Signed-off-by: Rafael J. Wysocki

PM / OPP: Simplify _opp_set_availability()

2017-01-30T08:22:22+00:00

As we don't use RCU locking anymore, there is no need to replace an
earlier OPP node with a new one. Just update the existing one.

Signed-off-by: Viresh Kumar 
Reviewed-by: Stephen Boyd 
Signed-off-by: Rafael J. Wysocki

PM / OPP: Move away from RCU locking

2017-01-30T08:22:22+00:00

The RCU locking isn't well suited for the OPP core. The RCU locking fits
better for reader heavy stuff, while the OPP core have at max one or two
readers only at a time.

Over that, it was getting very confusing the way RCU locking was used
with the OPP core. The individual OPPs are mostly well handled, i.e. for
an update a new structure was created and then that replaced the older
one. But the OPP tables were updated directly all the time from various
parts of the core. Though they were mostly used from within RCU locked
region, they didn't had much to do with RCU and were governed by the
mutex instead.

And that mixed with the 'opp_table_lock' has made the core even more
confusing.

Now that we are already managing the OPPs and the OPP tables with kernel
reference infrastructure, we can get rid of RCU locking completely and
simplify the code a lot.

Remove all RCU references from code and comments.

Acquire opp_table->lock while parsing the list of OPPs though.

Signed-off-by: Viresh Kumar 
Reviewed-by: Stephen Boyd 
Signed-off-by: Rafael J. Wysocki

PM / OPP: Take kref from _find_opp_table()

2017-01-30T08:22:22+00:00

Take reference of the OPP table from within _find_opp_table(). Also
update the callers of _find_opp_table() to call
dev_pm_opp_put_opp_table() after they have used the OPP table.

Note that _find_opp_table() increments the reference under the
opp_table_lock.

Now that the OPP table wouldn't get freed until the callers of
_find_opp_table() call dev_pm_opp_put_opp_table(), there is no need to
take the opp_table_lock or rcu_read_lock() around it. Drop them.

Signed-off-by: Viresh Kumar 
Reviewed-by: Stephen Boyd 
Signed-off-by: Rafael J. Wysocki

PM / OPP: Update OPP users to put reference

2017-01-30T08:22:21+00:00

This patch updates dev_pm_opp_find_freq_*() routines to get a reference
to the OPPs returned by them.

Also updates the users of dev_pm_opp_find_freq_*() routines to call
dev_pm_opp_put() after they are done using the OPPs.

As it is guaranteed the that OPPs wouldn't get freed while being used,
the RCU read side locking present with the users isn't required anymore.
Drop it as well.

This patch also updates all users of devfreq_recommended_opp() which was
returning an OPP received from the OPP core.

Note that some of the OPP core routines have gained
rcu_read_{lock|unlock}() calls, as those still use RCU specific APIs
within them.

Signed-off-by: Viresh Kumar 
Reviewed-by: Chanwoo Choi  [Devfreq]
Signed-off-by: Rafael J. Wysocki

PM / OPP: Add 'struct kref' to struct dev_pm_opp

2017-01-30T08:22:21+00:00

Add kref to struct dev_pm_opp for easier accounting of the OPPs.

Note that the OPPs are freed under the opp_table->lock mutex only.

Signed-off-by: Viresh Kumar 
Reviewed-by: Stephen Boyd 
Signed-off-by: Rafael J. Wysocki

PM / OPP: Use dev_pm_opp_get_opp_table() instead of _add_opp_table()

2017-01-30T08:22:21+00:00

Migrate all users of _add_opp_table() to use dev_pm_opp_get_opp_table()
to guarantee that the OPP table doesn't get freed while being used.

Also update _managed_opp() to get the reference to the OPP table.

Now that the OPP table wouldn't get freed while these routines are
executing after dev_pm_opp_get_opp_table() is called, there is no need
to take opp_table_lock. Drop them as well.

Now that _add_opp_table(), _remove_opp_table() and the unlocked release
routines aren't used anymore, remove them.

Signed-off-by: Viresh Kumar 
Reviewed-by: Stephen Boyd 
Signed-off-by: Rafael J. Wysocki