linux-stable.git/drivers/base/power/opp, branch linux-4.9.y

PM / OPP: Update voltage in case freq == old_freq

2018-07-11T14:26:45+00:00

commit c5c2a97b3ac7d1ec19e7cff9e38caca6afefc3de upstream.

This commit fixes a rare but possible case when the clk rate is updated
without update of the regulator voltage.

At boot up, CPUfreq checks if the system is running at the right freq. This
is a sanity check in case a bootloader set clk rate that is outside of freq
table present with cpufreq core. In such cases system can be unstable so
better to change it to a freq that is preset in freq-table.

The CPUfreq takes next freq that is >= policy->cur and this is our
target_freq that needs to be set now.

dev_pm_opp_set_rate(dev, target_freq) checks the target_freq and the
old_freq (a current rate). If these are equal it returns early. If not,
it searches for OPP (old_opp) that fits best to old_freq (not listed in
the table) and updates old_freq (!).

Here, we can end up with old_freq = old_opp.rate = target_freq, which
is not handled in _generic_set_opp_regulator(). It's supposed to update
voltage only when freq > old_freq  || freq > old_freq.

if (freq > old_freq) {
		ret = _set_opp_voltage(dev, reg, new_supply);
[...]
if (freq < old_freq) {
		ret = _set_opp_voltage(dev, reg, new_supply);
		if (ret)

It results in, no voltage update while clk rate is updated.

Example:
freq-table = {
	1000MHz   1.15V
	 666MHZ   1.10V
	 333MHz   1.05V
}
boot-up-freq        = 800MHz   # not listed in freq-table
freq = target_freq  = 1GHz
old_freq            = 800Mhz
old_opp = _find_freq_ceil(opp_table, &old_freq);  #(old_freq is modified!)
old_freq            = 1GHz

Fixes: 6a0712f6f199 ("PM / OPP: Add dev_pm_opp_set_rate()")
Cc: 4.6+  # v4.6+
Signed-off-by: Waldemar Rymarkiewicz 
Signed-off-by: Viresh Kumar 
Signed-off-by: Greg Kroah-Hartman

PM / OPP: Move error message to debug level

2017-12-25T13:23:44+00:00

[ Upstream commit 035ed07208dc501d023873447113f3f178592156 ]

On some i.MX6 platforms which do not have speed grading
check, opp table will not be created in platform code,
so cpufreq driver prints the following error message:

cpu cpu0: dev_pm_opp_get_opp_count: OPP table not found (-19)

However, this is not really an error in this case because the
imx6q-cpufreq driver first calls dev_pm_opp_get_opp_count()
and if it fails, it means that platform code does not provide
OPP and then dev_pm_opp_of_add_table() will be called.

In order to avoid such confusing error message, move it to
debug level.

It is up to the caller of dev_pm_opp_get_opp_count() to check its
return value and decide if it will print an error or not.

Signed-off-by: Fabio Estevam 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

PM / OPP: Add missing of_node_put(np)

2017-11-30T08:39:09+00:00

commit 7978db344719dab1e56d05e6fc04aaaddcde0a5e upstream.

The for_each_available_child_of_node() loop in _of_add_opp_table_v2()
doesn't drop the reference to "np" on errors. Fix that.

Fixes: 274659029c9d (PM / OPP: Add support to parse "operating-points-v2" bindings)
Signed-off-by: Tobias Jordan 
[ VK: Improved commit log. ]
Signed-off-by: Viresh Kumar 
Reviewed-by: Stephen Boyd 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

PM / OPP: Error out on failing to add static OPPs for v1 bindings

2017-11-15T14:53:12+00:00

[ Upstream commit 04a86a84c42ca18f37ab446127dc619b41dd3b23 ]

The code adding static OPPs for V2 bindings already does so. Make the V1
bindings specific code behave the same.

Signed-off-by: Viresh Kumar 
Reviewed-by: Stephen Boyd 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

PM / OPP: Don't use OPP structure outside of rcu protected section

2017-01-06T09:40:15+00:00

commit dc39d06fcd7a4a82d72eae7b71e94e888b96d29e upstream.

The OPP structure must not be used out of the rcu protected section.
Cache the values to be used in separate variables instead.

Signed-off-by: Viresh Kumar 
Reviewed-by: Stephen Boyd 
Tested-by: Dave Gerlach 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

PM / OPP: Pass opp_table to dev_pm_opp_put_regulator()

2017-01-06T09:40:15+00:00

commit 91291d9ad92faa65a56a9a19d658d8049b78d3d4 upstream.

Joonyoung Shim reported an interesting problem on his ARM octa-core
Odoroid-XU3 platform. During system suspend, dev_pm_opp_put_regulator()
was failing for a struct device for which dev_pm_opp_set_regulator() is
called earlier.

This happened because an earlier call to
dev_pm_opp_of_cpumask_remove_table() function (from cpufreq-dt.c file)
removed all the entries from opp_table->dev_list apart from the last CPU
device in the cpumask of CPUs sharing the OPP.

But both dev_pm_opp_set_regulator() and dev_pm_opp_put_regulator()
routines get CPU device for the first CPU in the cpumask. And so the OPP
core failed to find the OPP table for the struct device.

This patch attempts to fix this problem by returning a pointer to the
opp_table from dev_pm_opp_set_regulator() and using that as the
parameter to dev_pm_opp_put_regulator(). This ensures that the
dev_pm_opp_put_regulator() doesn't fail to find the opp table.

Note that similar design problem also exists with other
dev_pm_opp_put_*() APIs, but those aren't used currently by anyone and
so we don't need to update them for now.

Reported-by: Joonyoung Shim 
Signed-off-by: Stephen Boyd 
Signed-off-by: Viresh Kumar 
[ Viresh: Wrote commit log and tested on exynos 5250 ]
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

PM / OPP: Don't support OPP if it provides supported-hw but platform does not

2016-09-26T13:13:31+00:00

The OPP framework allows each OPP to set a opp-supported-hw property
which provides values that are matched against supported_hw values
provided by the platform to limit support for certain OPPs on specific
hardware. Currently, if the platform does not set supported_hw values,
all OPPs are interpreted as supported, even if they have provided their
own opp-supported-hw values.

If an OPP has provided opp-supported-hw, it is indicating that there is
some specific hardware configuration it is supported by. These constraints
should be honored, and if no supported_hw has been provided by the
platform, there is no way to determine if that OPP is actually supported,
so it should be marked as not supported.

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

PM / OPP: avoid maybe-uninitialized warning

2016-09-16T22:58:00+00:00

When CONFIG_OPTIMIZE_INLINING is set and we are building with -Wmaybe-uninitialized
enabled, we can get a warning for the opp core driver:

drivers/base/power/opp/core.c: In function 'dev_pm_opp_set_rate':
drivers/base/power/opp/core.c:560:8: warning: 'ou_volt_min' may be used uninitialized in this function [-Wmaybe-uninitialized]

This has only now appeared as a result of commit 797da5598f3a ("PM / devfreq:
Add COMPILE_TEST for build coverage"), which makes the driver visible in
some configurations that didn't have it before.

The warning is a false positive that I got with gcc-6.1.1, but there is
a simple workaround in removing the local variables that we get warnings
for (all three are affected depending on the configuration). This also
makes the code easier to read.

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

PM / OPP: optimize dev_pm_opp_set_rate() performance a bit

2016-07-28T21:54:16+00:00

In dev_pm_opp_set_rate(), _find_opp_table() is called 4 times: once by
_get_opp_clk(), once by dev_pm_opp_set_rate() itself, and twice by
dev_pm_opp_find_freq_ceil(). If there are several opp_tables in the
system, three times of opp table finding is a big waste. This patch
reduced the call of _find_opp_table() to twice.

Signed-off-by: Jisheng Zhang 
Acked-by: Viresh Kumar 
Signed-off-by: Rafael J. Wysocki

PM / OPP: Add 'UNKNOWN' status for shared_opp in struct opp_table

2016-06-16T13:50:36+00:00

dev_pm_opp_get_sharing_cpus() returns 0 even in the case when the OPP
core doesn't know whether or not the table is shared. It works on the
majority of platforms, where the OPP table is never created before
invoking the function and then -ENODEV is returned by it.

But in the case of one platform (Jetson TK1) at least, the situation
is a bit different. The OPP table has been created (somehow) before
dev_pm_opp_get_sharing_cpus() is called and it returns 0. Its caller
treats that as 'the CPUs don't share OPPs' and that leads to degraded
performance.

Fix this by converting 'shared_opp' in struct opp_table to an enum
and making dev_pm_opp_get_sharing_cpus() return -EINVAL in case when
the value of that field is "access unknown", so that the caller can
handle it accordingly (cpufreq-dt considers that as 'all CPUs share
the table', for example).

Fixes: 6f707daa3833 "PM / OPP: Add dev_pm_opp_get_sharing_cpus()"
Reported-and-tested-by: Alexandre Courbot 
Signed-off-by: Viresh Kumar 
[ rjw : Subject & changelog ]
Signed-off-by: Rafael J. Wysocki