linux-stable.git/drivers/opp/core.c, branch linux-5.7.y

opp: Put opp table in dev_pm_opp_set_rate() for empty tables

2020-08-26T09:42:09+00:00

[ Upstream commit 8979ef70850eb469e1094279259d1ef393ffe85f ]

We get the opp_table pointer at the top of the function and so we should
put the pointer at the end of the function like all other exit paths
from this function do.

Cc: v5.7+  # v5.7+
Fixes: aca48b61f963 ("opp: Manage empty OPP tables with clk handle")
Reviewed-by: Rajendra Nayak 
Signed-off-by: Stephen Boyd 
[ Viresh: Split the patch into two ]
Signed-off-by: Viresh Kumar 
Signed-off-by: Sasha Levin

opp: Reorder the code for !target_freq case

2020-08-26T09:42:09+00:00

[ Upstream commit b23dfa3543f31fbb8c0098925bf90fc23193d17a ]

Reorder the code a bit to make it more readable. Add additional comment
as well.

Tested-by: Marek Szyprowski 
Acked-by: Clément Péron 
Tested-by: Clément Péron 
Signed-off-by: Viresh Kumar 
Signed-off-by: Sasha Levin

opp: Enable resources again if they were disabled earlier

2020-08-26T09:42:09+00:00

[ Upstream commit a4501bac0e553bed117b7e1b166d49731caf7260 ]

dev_pm_opp_set_rate() can now be called with freq = 0 in order
to either drop performance or bandwidth votes or to disable
regulators on platforms which support them.

In such cases, a subsequent call to dev_pm_opp_set_rate() with
the same frequency ends up returning early because 'old_freq == freq'

Instead make it fall through and put back the dropped performance
and bandwidth votes and/or enable back the regulators.

Cc: v5.3+  # v5.3+
Fixes: cd7ea582866f ("opp: Make dev_pm_opp_set_rate() handle freq = 0 to drop performance votes")
Reported-by: Sajida Bhanu 
Reviewed-by: Sibi Sankar 
Reported-by: Matthias Kaehlcke 
Tested-by: Matthias Kaehlcke 
Reviewed-by: Stephen Boyd 
Signed-off-by: Rajendra Nayak 
[ Viresh: Don't skip clk_set_rate() and massaged changelog ]
Signed-off-by: Viresh Kumar 
Signed-off-by: Sasha Levin

opp: Manage empty OPP tables with clk handle

2020-04-13T10:44:55+00:00

With OPP core now supporting DVFS for IO devices, we have instances of
IO devices (same IP block) which require an OPP on some platforms/SoCs
while just needing to scale the clock on some others.

In order to avoid conditional code in every driver which supports such
devices (to check for availability of OPPs and then deciding to do
either dev_pm_opp_set_rate() or clk_set_rate()) add support to manage
empty OPP tables with a clk handle.

This makes dev_pm_opp_set_rate() equivalent of a clk_set_rate() for
devices with just a clk and no OPPs specified, and makes
dev_pm_opp_set_rate(0) bail out without throwing an error.

Signed-off-by: Rajendra Nayak 
Signed-off-by: Viresh Kumar

opp: Replace list_kref with a local counter

2019-12-10T10:27:00+00:00

A kref or refcount isn't the right tool to be used here for counting
number of devices that are sharing the static OPPs created for the OPP
table. For example, we are reinitializing the kref again, after it
reaches a value of 0 and frees the resources, if the static OPPs get
added for the same OPP table structure (as the OPP table structure was
never freed). That is messy and very unclear.

This patch makes parsed_static_opps an unsigned integer and uses it to
count the number of users of the static OPPs. The increment and
decrement to parsed_static_opps is done under opp_table->lock now to
make sure no races are possible if the OPP table is getting added and
removed in parallel (which doesn't happen in practice, but can in
theory).

Signed-off-by: Viresh Kumar

PM / OPP: Support adjusting OPP voltages at runtime

2019-11-11T04:57:15+00:00

On some SoCs the Adaptive Voltage Scaling (AVS) technique is
employed to optimize the operating voltage of a device. At a
given frequency, the hardware monitors dynamic factors and either
makes a suggestion for how much to adjust a voltage for the
current frequency, or it automatically adjusts the voltage
without software intervention. Add an API to the OPP library for
the former case, so that AVS type devices can update the voltages
for an OPP when the hardware determines the voltage should
change. The assumption is that drivers like CPUfreq or devfreq
will register for the OPP notifiers and adjust the voltage
according to suggestions that AVS makes.

This patch is derived from [1] submitted by Stephen.
[1] https://lore.kernel.org/patchwork/patch/599279/

Signed-off-by: Stephen Boyd 
[Roger Lu: Changed to rcu less implementation]
Signed-off-by: Roger Lu 
[s.nawrocki@samsung.com: added handling of OPP min/max voltage]
Signed-off-by: Sylwester Nawrocki 
Signed-off-by: Viresh Kumar

opp: core: Revert "add regulators enable and disable"

2019-10-21T02:28:12+00:00

All the drivers, which use the OPP framework control regulators, which
are already enabled. Typically those regulators are also system critical,
due to providing power to CPU core or system buses. It turned out that
there are cases, where calling regulator_enable() on such boot-enabled
regulator has side-effects and might change its initial voltage due to
performing initial voltage balancing without all restrictions from the
consumers. Until this issue becomes finally solved in regulator core,
avoid calling regulator_enable()/disable() from the OPP framework.

This reverts commit 7f93ff73f7c8c8bfa6be33bcc16470b0b44682aa.

Signed-off-by: Marek Szyprowski 
Reviewed-by: Mark Brown 
Signed-off-by: Viresh Kumar

opp: core: add regulators enable and disable

2019-07-26T07:55:52+00:00

Add enable regulators to dev_pm_opp_set_regulators() and disable
regulators to dev_pm_opp_put_regulators(). Even if bootloader
leaves regulators enabled, they should be enabled in kernel in
order to increase the reference count.

Signed-off-by: Kamil Konieczny 
Signed-off-by: Viresh Kumar

opp: Don't decrement uninitialized list_kref

2019-07-26T07:55:52+00:00

The list_kref was added for static OPPs and to track their users. The
kref is initialized while the static OPPs are added, but removed
unconditionally even if the static OPPs were never added. This causes
refcount mismatch warnings currently.

Fix that by always initializing the kref when the OPP table is first
initialized. The refcount is later incremented only for the second user
onwards.

Fixes: d0e8ae6c26da ("OPP: Create separate kref for static OPPs list")
Reported-by: Rajendra Nayak 
Signed-off-by: Viresh Kumar

opp: Add dev_pm_opp_find_level_exact()

2019-07-26T07:54:59+00:00

Since the performance states in the OPP table are unique, implement a
dev_pm_opp_find_level_exact() in order to be able to fetch a specific OPP.

Signed-off-by: Niklas Cassel 
[ Viresh: Updated commit log ]
Signed-off-by: Viresh Kumar