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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 <viresh.kumar@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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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 <viresh.kumar@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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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 <viresh.kumar@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Add kref to struct opp_table for easier accounting of the OPP table.
Note that the new routine dev_pm_opp_get_opp_table() takes the reference
from under the opp_table_lock, which guarantees that the OPP table
doesn't get freed unless dev_pm_opp_put_opp_table() is called for the
OPP table.
Two separate release mechanisms are added: locked and unlocked. In
unlocked version the routines aren't required to take/drop
opp_table_lock as the callers have already done that. This is required
to avoid breaking git bisect, otherwise we may get lockdeps between
commits. Once all the users of OPP table are updated the unlocked
version shall be removed.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Add per OPP table lock to protect opp_table->opp_list.
Note that at few places opp_list is used under the rcu_read_lock() and
so a mutex can't be added there for now. This will be fixed by a later
patch.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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There is no point in trying to find/allocate the table for every OPP
that is added for a device. It would be far more efficient to allocate
the table only once and pass its pointer to the routines that add the
OPP entry.
Locking is removed from _opp_add_static_v2() and _opp_add_v1() now as
the callers call them with that lock already held.
Call to _remove_opp_table() routine is also removed from _opp_free()
now, as opp_table isn't allocated from within _opp_allocate(). This is
handled by the routines which created the OPP table in the first place.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Later patches would want to remove OPP table (and its OPPs) using the
opp_table pointer instead of 'dev'.
In order to prepare for that, rename _dev_pm_opp_remove_table() as
_dev_pm_opp_find_and_remove_table() split out part of it.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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The OPPs which are never successfully added using _opp_add() are not
required to be freed with the _opp_remove() routine, as a simple kfree()
is enough for them.
Introduce a new light weight routine _opp_free(), which will do that.
That also helps us removing the 'notify' parameter to _opp_remove(),
which isn't required anymore.
Note that _opp_free() contains a call to _remove_opp_table() as the OPP
table might have been added for this very OPP only. The
_remove_opp_table() routine returns quickly if there are more OPPs in
the table. This will be simplified in later patches though.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Make the naming consistent with how other routines are named.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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The generic set_opp() handler isn't sufficient for platforms with
complex DVFS. For example, some TI platforms have multiple regulators
for a CPU device. The order in which various supplies need to be
programmed is only known to the platform code and its best to leave it
to it.
This patch implements APIs to register platform specific set_opp()
callback.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Dave Gerlach <d-gerlach@ti.com>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Later patches would add support for custom set_opp() callbacks. This
patch separates out the code for _generic_set_opp() handler in order to
prepare for that.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Dave Gerlach <d-gerlach@ti.com>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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This patch adds infrastructure to manage multiple regulators and updates
the only user (cpufreq-dt) of dev_pm_opp_set{put}_regulator().
This is preparatory work for adding full support for devices with
multiple regulators.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Dave Gerlach <d-gerlach@ti.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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This is a preparatory step for multiple regulator per device support.
Move the voltage/current variables to a new structure.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Dave Gerlach <d-gerlach@ti.com>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Since commit f47b72a15a96 ("PM / OPP: Move CONFIG_OF dependent code
in a separate file"), this function is defined and called only in
drivers/base/power/opp/of.c .
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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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 <acourbot@nvidia.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw : Subject & changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Recently, a few issues were noticed in the code where CONFIG_OF wasn't
consistently used for many routines. The core file is big enough now and
ifdef hackery makes it less readable.
Move OF-specific code to another file and compile that only if CONFIG_OF
is enabled.
Compile-tested:
- For ARM (exynos) with CONFIG_OF enabled
- For X86 with CONFIG_OF disabled (have to enable CONFIG_PM_OPP separately)
No functional changes.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Stephen pointed out recently, that few structures always confuse him as
they aren't named properly. And this patch tries to address that:
Names are updated as:
- device_opp or dev_opp -> opp_table
- dev_opp_list -> opp_tables
- dev_opp_list_lock -> opp_table_lock
- device_list_opp -> opp_device (it was never a list, but a structure)
- list_dev -> opp_dev
- And similar changes in comments and function names as well.
This also fixes checkpatch warnings that were generated with this patch.
No functional changes.
Suggested-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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OPP core has got almost everything now to manage device's OPP
transitions, the only thing left is device's clk. Get that as well.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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V2 bindings have better support for clock-latency and voltage-tolerance
and doesn't need special care. To use callbacks, like
dev_pm_opp_get_max_{transition|volt}_latency(), irrespective of the
bindings, the core needs to know clock-latency/voltage-tolerance for the
earlier bindings.
This patch reads clock-latency/voltage-tolerance from the device node,
irrespective of the bindings (to keep it simple) and use them only for
V1 bindings.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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This allows the OPP core to request/free the regulator resource,
attached to a device OPP. The regulator device is fetched using the name
provided by the driver, while calling: dev_pm_opp_set_regulator().
This will work for both OPP-v1 and v2 bindings.
This is a preliminary step for moving the OPP switching logic into the
OPP core.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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OPP bindings (for few properties) allow a platform to choose a
value/range among a set of available options. The options are present as
opp-<prop>-<name>, where the platform needs to supply the <name> string.
The OPP properties which allow such an option are: opp-microvolt and
opp-microamp.
Add support to the OPP-core to parse these bindings, by introducing
dev_pm_opp_{set|put}_prop_name() APIs.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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OPP bindings allow a platform to enable OPPs based on the version of the
hardware they are used for.
Add support to the OPP-core to parse these bindings, by introducing
dev_pm_opp_{set|put}_supported_hw() APIs.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Few doc-style comments were missing, add them. Rearrange another one to
match the sequence within the structure.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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This patch adds debugfs support to OPP layer to export OPPs and their
properties for all the devices.
This creates a top level directory: /sys/kernel/debug/opp and then
device specific directories (based on device names) inside it. For
example: 'cpu0', 'cpu1', etc..
If multiple devices share the OPP table, then the real directory is
created only for the first device. For all others, links are created to
the real directory.
Inside the device specific directory, a separate directory is created
for each OPP. And within that files per opp property.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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dev_opp_list_lock is used everywhere to protect device and OPP lists,
but dev_pm_opp_set_sharing_cpus() is missed somehow. And instead we used
rcu-lock, which wouldn't help here as we are adding a new list_dev.
This also fixes a problem where we have called kzalloc(..., GFP_KERNEL)
from within rcu-lock, which isn't allowed as kzalloc can sleep when
called with GFP_KERNEL.
With CONFIG_DEBUG_ATOMIC_SLEEP set, we get following lockdep-splat:
include/linux/rcupdate.h:578 Illegal context switch in RCU read-side critical section!
other info that might help us debug this:
rcu_scheduler_active = 1, debug_locks = 0
5 locks held by swapper/0/1:
#0: (&dev->mutex){......}, at: [<c02f68f4>] __driver_attach+0x48/0x98
#1: (&dev->mutex){......}, at: [<c02f6904>] __driver_attach+0x58/0x98
#2: (cpu_hotplug.lock){++++++}, at: [<c00249d0>] get_online_cpus+0x40/0xb0
#3: (subsys mutex#5){+.+.+.}, at: [<c02f4f8c>] subsys_interface_register+0x44/0xdc
#4: (rcu_read_lock){......}, at: [<c0305c80>] dev_pm_opp_set_sharing_cpus+0x0/0x1e4
stack backtrace:
CPU: 1 PID: 1 Comm: swapper/0 Tainted: G W 4.3.0-rc7-00047-g81f5932958a8 #59
Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
[<c0016874>] (unwind_backtrace) from [<c001355c>] (show_stack+0x10/0x14)
[<c001355c>] (show_stack) from [<c022553c>] (dump_stack+0x94/0xbc)
[<c022553c>] (dump_stack) from [<c004904c>] (___might_sleep+0x24c/0x298)
[<c004904c>] (___might_sleep) from [<c00f07e4>] (kmem_cache_alloc+0xe8/0x164)
[<c00f07e4>] (kmem_cache_alloc) from [<c0305354>] (_add_list_dev+0x30/0x58)
[<c0305354>] (_add_list_dev) from [<c0305d50>] (dev_pm_opp_set_sharing_cpus+0xd0/0x1e4)
[<c0305d50>] (dev_pm_opp_set_sharing_cpus) from [<c040eda4>] (cpufreq_init+0x4cc/0x62c)
[<c040eda4>] (cpufreq_init) from [<c040a964>] (cpufreq_online+0xbc/0x73c)
[<c040a964>] (cpufreq_online) from [<c02f4fe0>] (subsys_interface_register+0x98/0xdc)
[<c02f4fe0>] (subsys_interface_register) from [<c040a640>] (cpufreq_register_driver+0x110/0x17c)
[<c040a640>] (cpufreq_register_driver) from [<c040ef64>] (dt_cpufreq_probe+0x60/0x8c)
[<c040ef64>] (dt_cpufreq_probe) from [<c02f8084>] (platform_drv_probe+0x44/0xa4)
[<c02f8084>] (platform_drv_probe) from [<c02f67c0>] (driver_probe_device+0x208/0x2f4)
[<c02f67c0>] (driver_probe_device) from [<c02f6940>] (__driver_attach+0x94/0x98)
[<c02f6940>] (__driver_attach) from [<c02f4c1c>] (bus_for_each_dev+0x68/0x9c)
Reported-by: Michael Turquette <mturquette@baylibre.com>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: 4.3 <stable@vger.kernel.org> # 4.3
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Move cpu device specific code out of generic opp library, and add it to
cpu.c.
Along with that, create a core-internal opp.h header, which will be used
to share structures and function prototypes within opp core.
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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