<feed xmlns='http://www.w3.org/2005/Atom'>
<title>lwn.git/drivers/cpufreq/omap-cpufreq.c, branch docs-5.13</title>
<subtitle>Linux kernel documentation tree maintained by Jonathan Corbet</subtitle>
<id>http://mirrors.hust.edu.cn/git/lwn.git/atom?h=docs-5.13</id>
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<updated>2021-02-04T18:23:20+00:00</updated>
<entry>
<title>cpufreq: Remove CPUFREQ_STICKY flag</title>
<updated>2021-02-04T18:23:20+00:00</updated>
<author>
<name>Viresh Kumar</name>
<email>viresh.kumar@linaro.org</email>
</author>
<published>2021-02-02T04:55:11+00:00</published>
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<id>urn:sha1:5ae4a4b45d4396aa7f7c008c4ae9eca981d43f8c</id>
<content type='text'>
During cpufreq driver's registration, if the -&gt;init() callback for all
the CPUs fail then there is not much point in keeping the driver around
as it will only account for more of unnecessary noise, for example
cpufreq core will try to suspend/resume the driver which never got
registered properly.

The removal of such a driver is avoided if the driver carries the
CPUFREQ_STICKY flag. This was added way back [1] in 2004 and perhaps no
one should ever need it now. A lot of drivers do set this flag, probably
because they just copied it from other drivers.

This was added earlier for some platforms [2] because their cpufreq
drivers were getting registered before the CPUs were registered with
subsys framework. And hence they used to fail.

The same isn't true anymore though. The current code flow in the kernel
is:

start_kernel()
-&gt; kernel_init()
   -&gt; kernel_init_freeable()
      -&gt; do_basic_setup()
         -&gt; driver_init()
            -&gt; cpu_dev_init()
               -&gt; subsys_system_register() //For CPUs

         -&gt; do_initcalls()
            -&gt; cpufreq_register_driver()

Clearly, the CPUs will always get registered with subsys framework
before any cpufreq driver can get probed. Remove the flag and update the
relevant drivers.

Link: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git/commit/include/linux/cpufreq.h?id=7cc9f0d9a1ab04cedc60d64fd8dcf7df224a3b4d # [1]
Link: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git/commit/arch/arm/mach-sa1100/cpu-sa1100.c?id=f59d3bbe35f6268d729f51be82af8325d62f20f5 # [2]
Signed-off-by: Viresh Kumar &lt;viresh.kumar@linaro.org&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
</entry>
<entry>
<title>OPP: refactor dev_pm_opp_of_register_em() and update related drivers</title>
<updated>2020-06-24T15:16:42+00:00</updated>
<author>
<name>Lukasz Luba</name>
<email>lukasz.luba@arm.com</email>
</author>
<published>2020-05-27T09:58:54+00:00</published>
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<id>urn:sha1:0e0ffa855d1590e54ec0033404a49e2e57e294fe</id>
<content type='text'>
The Energy Model framework supports not only CPU devices. Drop the CPU
specific interface with cpumask and add struct device. Add also a return
value, user might use it. This new interface provides easy way to create
a simple Energy Model, which then might be used by e.g. thermal subsystem.

Acked-by: Daniel Lezcano &lt;daniel.lezcano@linaro.org&gt;
Signed-off-by: Lukasz Luba &lt;lukasz.luba@arm.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
</entry>
<entry>
<title>Merge branch 'pm-cpufreq'</title>
<updated>2019-07-18T07:49:30+00:00</updated>
<author>
<name>Rafael J. Wysocki</name>
<email>rafael.j.wysocki@intel.com</email>
</author>
<published>2019-07-18T07:49:30+00:00</published>
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<id>urn:sha1:918e162e6a71e924a343b41f71789ad14e1e3229</id>
<content type='text'>
* pm-cpufreq:
  cpufreq: Make cpufreq_generic_init() return void
  cpufreq: imx-cpufreq-dt: Add i.MX8MN support
  cpufreq: Add QoS requests for userspace constraints
  cpufreq: intel_pstate: Reuse refresh_frequency_limits()
  cpufreq: Register notifiers with the PM QoS framework
  PM / QoS: Add support for MIN/MAX frequency constraints
  PM / QOS: Pass request type to dev_pm_qos_read_value()
  PM / QOS: Rename __dev_pm_qos_read_value() and dev_pm_qos_raw_read_value()
  PM / QOS: Pass request type to dev_pm_qos_{add|remove}_notifier()
</content>
</entry>
<entry>
<title>cpufreq: Make cpufreq_generic_init() return void</title>
<updated>2019-07-16T08:20:11+00:00</updated>
<author>
<name>Viresh Kumar</name>
<email>viresh.kumar@linaro.org</email>
</author>
<published>2019-07-16T04:06:08+00:00</published>
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<id>urn:sha1:c4dcc8a162784c1f827c7f6d8409598f19708fe6</id>
<content type='text'>
It always returns 0 (success) and its return type should really be void.

Over that, many drivers have added error handling code based on its
return value, which is not required at all.

Change its return type to void and update all the callers.

Signed-off-by: Viresh Kumar &lt;viresh.kumar@linaro.org&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
</entry>
<entry>
<title>treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500</title>
<updated>2019-06-19T15:09:55+00:00</updated>
<author>
<name>Thomas Gleixner</name>
<email>tglx@linutronix.de</email>
</author>
<published>2019-06-04T08:11:33+00:00</published>
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<id>urn:sha1:d2912cb15bdda8ba4a5dd73396ad62641af2f520</id>
<content type='text'>
Based on 2 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Reviewed-by: Enrico Weigelt &lt;info@metux.net&gt;
Reviewed-by: Kate Stewart &lt;kstewart@linuxfoundation.org&gt;
Reviewed-by: Allison Randal &lt;allison@lohutok.net&gt;
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>cpufreq: OMAP: Register an Energy Model</title>
<updated>2019-02-07T04:37:36+00:00</updated>
<author>
<name>Yangtao Li</name>
<email>tiny.windzz@gmail.com</email>
</author>
<published>2019-02-07T04:35:50+00:00</published>
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<id>urn:sha1:a9a744dd5b82843a9c99d9f97794fb51bc2ed8dd</id>
<content type='text'>
Try and register an Energy Model from omap-cpufreq.c to allow
interested subsystems like the task scheduler to use the provided
information.

Signed-off-by: Yangtao Li &lt;tiny.windzz@gmail.com&gt;
Signed-off-by: Viresh Kumar &lt;viresh.kumar@linaro.org&gt;
</content>
</entry>
<entry>
<title>PM / OPP: Update OPP users to put reference</title>
<updated>2017-01-30T08:22:21+00:00</updated>
<author>
<name>Viresh Kumar</name>
<email>viresh.kumar@linaro.org</email>
</author>
<published>2017-01-23T04:41:47+00:00</published>
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<id>urn:sha1:8a31d9d94297b1ecae3012069d35d78c959693c2</id>
<content type='text'>
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 &lt;viresh.kumar@linaro.org&gt;
Reviewed-by: Chanwoo Choi &lt;cw00.choi@samsung.com&gt; [Devfreq]
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
</entry>
<entry>
<title>remove lots of IS_ERR_VALUE abuses</title>
<updated>2016-05-27T22:26:11+00:00</updated>
<author>
<name>Arnd Bergmann</name>
<email>arnd@arndb.de</email>
</author>
<published>2016-05-27T21:23:25+00:00</published>
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<id>urn:sha1:287980e49ffc0f6d911601e7e352a812ed27768e</id>
<content type='text'>
Most users of IS_ERR_VALUE() in the kernel are wrong, as they
pass an 'int' into a function that takes an 'unsigned long'
argument. This happens to work because the type is sign-extended
on 64-bit architectures before it gets converted into an
unsigned type.

However, anything that passes an 'unsigned short' or 'unsigned int'
argument into IS_ERR_VALUE() is guaranteed to be broken, as are
8-bit integers and types that are wider than 'unsigned long'.

Andrzej Hajda has already fixed a lot of the worst abusers that
were causing actual bugs, but it would be nice to prevent any
users that are not passing 'unsigned long' arguments.

This patch changes all users of IS_ERR_VALUE() that I could find
on 32-bit ARM randconfig builds and x86 allmodconfig. For the
moment, this doesn't change the definition of IS_ERR_VALUE()
because there are probably still architecture specific users
elsewhere.

Almost all the warnings I got are for files that are better off
using 'if (err)' or 'if (err &lt; 0)'.
The only legitimate user I could find that we get a warning for
is the (32-bit only) freescale fman driver, so I did not remove
the IS_ERR_VALUE() there but changed the type to 'unsigned long'.
For 9pfs, I just worked around one user whose calling conventions
are so obscure that I did not dare change the behavior.

I was using this definition for testing:

 #define IS_ERR_VALUE(x) ((unsigned long*)NULL == (typeof (x)*)NULL &amp;&amp; \
       unlikely((unsigned long long)(x) &gt;= (unsigned long long)(typeof(x))-MAX_ERRNO))

which ends up making all 16-bit or wider types work correctly with
the most plausible interpretation of what IS_ERR_VALUE() was supposed
to return according to its users, but also causes a compile-time
warning for any users that do not pass an 'unsigned long' argument.

I suggested this approach earlier this year, but back then we ended
up deciding to just fix the users that are obviously broken. After
the initial warning that caused me to get involved in the discussion
(fs/gfs2/dir.c) showed up again in the mainline kernel, Linus
asked me to send the whole thing again.

[ Updated the 9p parts as per Al Viro  - Linus ]

Signed-off-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Cc: Andrzej Hajda &lt;a.hajda@samsung.com&gt;
Cc: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Link: https://lkml.org/lkml/2016/1/7/363
Link: https://lkml.org/lkml/2016/5/27/486
Acked-by: Srinivas Kandagatla &lt;srinivas.kandagatla@linaro.org&gt; # For nvmem part
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>cpufreq: Use consistent prefixing via pr_fmt</title>
<updated>2016-04-08T23:35:18+00:00</updated>
<author>
<name>Joe Perches</name>
<email>joe@perches.com</email>
</author>
<published>2016-04-05T20:28:25+00:00</published>
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<id>urn:sha1:1c5864e26c99cf32b51e878f3daf73a388d7561a</id>
<content type='text'>
Use the more common kernel style adding a define for pr_fmt.

Miscellanea:

o Remove now unused PFX defines

Signed-off-by: Joe Perches &lt;joe@perches.com&gt;
Acked-by: Viresh Kumar &lt;viresh.kumar@linaro.org&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
</entry>
<entry>
<title>cpufreq: Convert printk(KERN_&lt;LEVEL&gt; to pr_&lt;level&gt;</title>
<updated>2016-04-08T23:35:18+00:00</updated>
<author>
<name>Joe Perches</name>
<email>joe@perches.com</email>
</author>
<published>2016-04-05T20:28:24+00:00</published>
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<id>urn:sha1:b49c22a6ca3656c68506fea57caf3d8f08878570</id>
<content type='text'>
Use the more common logging style.

Miscellanea:

o Coalesce formats
o Realign arguments
o Add a missing space between a coalesced format

Signed-off-by: Joe Perches &lt;joe@perches.com&gt;
Acked-by: Viresh Kumar &lt;viresh.kumar@linaro.org&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
</entry>
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