qup_i2c: Set parent device to enable runtime PM support for clients

Register the current device as parent of the adaptor device in order to
allow the client drivers to use runtime PM.  Client drivers can vote to
enable and disable clocks as needed.

Change-Id: Ie2d6b96ab0cbe5af56b4da0f5f18b37d0495e053
Acked-by: Christian Bolis <cbolis@qti.qualcomm.com>
Signed-off-by: Kenneth Heitke <kheitke@codeaurora.org>
i2c_qup: always set rate and log a message when fail

Clock set rate is failing silently when clock rate is not
available. Additionally clock rate is not set when no rate
is specified in platform data. This patch always set the
clock's rate and logs a message if it fails to set rate
or if no rate is set by platfrom data.

CRs-Fixed: 452047
Change-Id: I0551a12ca2861f8e1a48ee344d6ffcf898c96971
Signed-off-by: Gilad Avidov <gavidov@codeaurora.org>
qup_i2c: Avoid potential panic issue

I2c register access is happening in isr before PM runtime
status check. This can lead to potential hang because of
unwanted interrupts and i2c clocks are off.

Update the i2c driver code to have register access
after PM runtime status check.

CRs-Fixed: 454710
Change-Id: I11a3d8df24c514205203f24be8e08d7c1ea1a7b8
Signed-off-by: Alok Chauhan <alokc@codeaurora.org>
qup_i2c: Use separate variables to store i2c gpios settings

In i2c bus recovery function GPIO settings for both
SCL and SDA are stored in one variable in this order
before writing recovery settings.
So, SCL setting is overwritten with SDA setting.
And when saved gpios settings write it back after
recovery, the setting for SDA is written both on SCL and SDA.
It means the setting of SCL is broken.

Use separate instances of variables to store GPIO settings
of SDA and SCL separately

CRs-Fixed: 447585
Change-Id: I7014a5b12d4c7ef41fd28c543834d45c619695a9
Signed-off-by: Alok Chauhan <alokc@codeaurora.org>
qup_i2c: Update clock ready check condition

While doing i2c transfer that involved write and
immediate read, the driver will put the controller
to RESET and do an immediate read before the write completes.
This issue is hard to produce internally because clock stretch
from slave device is involved during the failure time. CLK
state in QUP status register will be FORCED_LOW_STATE.

O/p fifo empty check added to determine clock idle.

CRs-Fixed: 455743
Change-Id: I51c1d9f9de42381fc85710e9185aa4177f6cd302
Signed-off-by: Alok Chauhan <alokc@codeaurora.org>
msm: devices-msm8x60: increase watchdog bark time to prevent abnormal watchdog timeout reboot
fuji: enable kernel same page merging
Revert "msm: Synchronize CPU frequency on thread migration"

This reverts commit 292520ddaf5d0b77e26900b30c25313959d7c75a.
cpufreq: Avoid using smp_processor_id() in preemptible context

Even though this work item runs on only one cpu at a time (due to
queue_work_on()) it is possible for the work item to be preempted
and so use of smp_processor_id() is illegal.

BUG: using smp_processor_id() in preemptible [00000000]
code: kworker/3:1/4162 caller is dbs_refresh_callback+0xc/0x188
[<c00151b0>] (unwind_backtrace+0x0/0x120) from [<c0279058>]
(debug_smp_processor_id+0xbc/0xf0)
[<c0279058>] (debug_smp_processor_id+0xbc/0xf0) from [<c0454b54>]
(dbs_refresh_callback+0xc/0x188)
[<c0454b54>] (dbs_refresh_callback+0xc/0x188) from [<c0087290>]
(process_one_work+0x354/0x648)
[<c0087290>] (process_one_work+0x354/0x648) from [<c0089754>]
(worker_thread+0x1a8/0x2a8)
[<c0089754>] (worker_thread+0x1a8/0x2a8) from [<c008e480>]
(kthread+0x90/0xa0)
[<c008e480>] (kthread+0x90/0xa0) from [<c000f438>]
(kernel_thread_exit+0x0/0x8)

The intent of the code is to determine which CPU this work item
is running on, which we can easily do by passing that information
in a wrapper struct around the work struct. Do this so we avoid
this problem.

Change-Id: I05ca0ff2b3cbaa239930463ea0760e3e9d75145f
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
cpufreq: ondemand: Fix kernel warning in cpufreq_governor_dbs

GOV_STOP event destroys the timer_mutex and is not initialized back
upon GOV_START event.
The Kernel complains at mutex_lock(during GOV_LIMITS event) after
mutex_destroy.

[<c0014918>] (unwind_backtrace+0x0/0x11c)
[<c007c004>] (warn_slowpath_common+0x4c/0x64)
[<c007c034>] (warn_slowpath_null+0x18/0x1c)
[<c079eef8>] (__mutex_lock_slowpath+0x130/0x3c4)
[<c079f1ac>] (mutex_lock+0x20/0x3c) from [<c0540900>]
[<c0540900>] (cpufreq_governor_dbs+0x3c8/0x468)
[<c053d500>] (__cpufreq_governor+0x90/0xe0)
[<c053d774>] (__cpufreq_set_policy+0x224/0x258)
[<c053da58>] (cpufreq_add_dev_interface+0x2b0/0x308)
[<c053e784>] (cpufreq_add_dev+0x500/0x56c)
[<c079247c>] (cpufreq_cpu_callback+0x88/0x9c)
[<c07a2ca8>] (notifier_call_chain+0x38/0x68)
[<c007ded0>] (__cpu_notify+0x28/0x40)
[<c0790024>] (_cpu_up+0xe4/0x118)
[<c0790024>] (cpu_up+0x64/0x80)
[<c0765840>] (store_online+0x48/0x78)
[<c038d0c8>] (dev_attr_store+0x18/0x24)
[<c017be40>] (sysfs_write_file+0x108/0x13c)
[<c012cdfc>] (vfs_write+0xb0/0x128)
[<c012d034>](sys_write+0x38/0x64)

Change-Id: Ie2a796b17209243de731ccf2ab04b7f9e7048df8
Signed-off-by: Anji Jonnala <anjir@codeaurora.org>
msm: cpufreq: make the gov stop part fully atomic

In the function cpufreq_governor_dbs, the case CPUFREQ_GOV_STOP
is not completely atomic. The removal of sysfs is outside the
critical path. If a START/STOP done frequently from user space
then there is chance of adding the sysfs interface before removal.
This creates a warning from sysfs saying creating an already
existing entry.

Also once it fails to create, cpufreq_governor_dbs returns with
error code. The dbs_enable value is incremented which is not
rolled back and cpufreq core tries to set the old
governor. This might create further problems.

Hence the removal of sysfs entry should happen in the critical
path.

CRs-fixed: 440969
Change-Id: I98891756caf2ce0b85e39e9b4f58034af1ed97ce
Signed-off-by: Venkat Devarasetty <vdevaras@codeaurora.org>
cpufreq: Retain only online cpus in managed_policy->cpus

cpufreq's handling of cpu online event can incorrectly initialize
managed_policy->cpus to include offline cpus. This causes cpufreq
governors to include offline cpus in their idle time computation, which
causes frequency to shoot up beyond normal levels (on systems where 2 or
more cpus need to be synchronized wrt frequency change).

This frequency shootup was not seen prior to commit 21111be8 which
changed idle time accounting for offline cpus. Prior to commit 21111be8,
idle time statistics for offline cpus would include their offline time
as well. Post commit 21111be8, offline time is not included in a cpu's
idle time statistics.

As a result, ondemand (or other cpufreq) governors would see unchanged
idle time for offline cpus, causing them to interpret those (offline)
cpus as 100% busy, which is wrong.

This patch fixes the issue by modifying cpufreq's hotplug handling to
retain only online cpus in managed_policy->cpus field. cpufreq governors
would then skip such offline cpus from idle time calculations.

Change-Id: Id2eba8c0ec3367609369b2e42a4e1386ff2e7ab5
Signed-off-by: Srivatsa Vaddagiri <vatsa@codeaurora.org>
cpufreq: Fix optimal_freq logic on ramp down

When ondemand governor decides to ramp down the frequency, the missing
check for frequency being lower than optimal_freq was causing frequency
to be ramped down to optimal_freq even if the frequency decided by ondemand
governor was higher.

Change-Id: I00f9ae4c61ccda4039f3338dee2c29b8cb790be4
Signed-off-by: Veena Sambasivan <veenas@codeaurora.org>
msm: Synchronize CPU frequency on thread migration

Sometimes when foreground threads, crucial for UI, migrate
from a core at higher frequency to the one running at a lower
frequency, it could badly affect performance for cases like
scrolling.
This change tries to raise the frequency of the destination core
to the same value as the source core, if it is not already running
at the same or higher frequency.  In order for the ondemand
governor to have a fair idea of load in the next sample, it also
reschedules the next sample one sampling interval from the
frequency transition after which the ondemand governor again
takes over.

Signed-off-by: Rohit Gupta <rohgup@codeaurora.org>
Change-Id: I9d2fbb166b0cc042d3fd57cea75a5066df4c794b
cpufreq: Use dedicated high-priority workqueues

In the process of scaling CPU frequencies, cpufreq and the APIS is
calls may hold resources that will prevent threads critical for
system stability from running.

Specifically, thermal-mitigation software may need to respond
quickly to high-temperature conditions and throttle the CPU speed
in an effort to cool down. If the system is already in the middle
of a CPU frequency switch being executed on behalf of a cpufreq
governor, thermal mitigation will be blocked until the scaling
action has completed. If the system is under heave load of medium
or high-priority threads, this may take a long while and the system
may potentially surpass thermal limits in the meantime.

Resolve this by using high priority workqueues for all ondemand
and conservative governor scaling operations.  This will allow them
to complete promptly and release their hold on resources necessary
for maintaining system stability.

Change-Id: I2f56052c131442838036cf4cdd8059f7c09bb805
Signed-off-by: Matt Wagantall <mattw@codeaurora.org>
Signed-off-by: Ajay Dudani <adudani@codeaurora.org>
cpufreq: ondemand: change freq sync code to use per-CPU kthreads

The migration notifier may run in a context where it is not safe to
enqueue a work item. For example:

(__queue_work+0x1f4/0x40c)
(queue_work_on+0x34/0x44)
(dbs_migration_notify+0x2c/0x40)
(notifier_call_chain+0x38/0x68)
(__atomic_notifier_call_chain+0x34/0x44)
(atomic_notifier_call_chain+0x14/0x18)
(try_to_wake_up+0x350/0x36c)
(autoremove_wake_function+0xc/0x34)
(__wake_up_common+0x48/0x7c)
(__wake_up+0x3c/0x50)
(trustee_thread+0x1d0/0x528)
(kthread+0x80/0x8c)

The trustee code already takes a lock internal to the workqueue
implementation and is not expecting a wake up to come around and
enter the workqueue code again, where the same lock will be needed.

Instead of relying on a workqueue, use a per-CPU kthread to do
the frequency syncing.

Change-Id: I7555ee40867792fa8ec4ea8f9a6309323775e797
Signed-off-by: Steve Muckle <smuckle@codeaurora.org>
Signed-off-by: Ajay Dudani <adudani@codeaurora.org>
cpufreq: ondemand: Fix store_powersave_bias() race with hotplug

store_powersave_bias() assumes that CPUs will not be taken offline or
brought online while executing its for_each_online_cpu() loops. Fix
this race by blocking hotplug while executing in these loop.

CRs-Fixed: 494407
Change-Id: I0d5520444ec21a8d9b12fb73c06ac8442449fa85
Signed-off-by: Matt Wagantall <mattw@codeaurora.org>
cpufreq: ondemand: Fix locking in store_powersave_bias

store_powersave_bias() assumes that dbs_info->cur_policy will
not change while it is executing. If it does, memory corruption
can potentially result. Fix this by acquiring the dbs_lock.

Most noticeably, this resolves timer-related list corruptions
encountered when queue_delayed_work_on() is called from within
store_powersave_bias() while a CPU is being hotplugged in and
out.

CRs-Fixed: 494407
Change-Id: I0fd5cbef6834545274cad9481e574ec50b37b871
Signed-off-by: Matt Wagantall <mattw@codeaurora.org>
cpufreq: ondemand: Fix locking issue in store_powersave_bias

store_powersave_bias takes timer_mutex before calling dbs_timer_exit
which tries to cancel the delayed work do_dbs_timer which in turn
tries to take the same lock. This can cause a lock recursion under
the race condition where can cancel_delayed_work_sync is called
when the work has already started executing.

This can be avoided by taking that lock after calling
dbs_timer_exit.

Change-Id: I7f862286e66f1ddc1e13e4eeee369dd188fc10d5
Signed-off-by: Rohit Gupta <rohgup@codeaurora.org>
msm: cpufreq: Only apply driver limits for scaling_min/max_freq writes

When new values are written to scaling_min/max_freq sysfs files, the
current code applies all the limits imposed by various ADJUST and
INCOMPATIBLE notifiers handlers before storing them.

When the ADJUST and/or INCOMPATIBLE notifiers change their limits
frequently, this behavior makes it almost impossible for a
user/userspace process to store the scaling_min/max_freq limits
that go beyond the instantaneous limits imposed by the notifiers.
Since these sysfs nodes are typically meant to set limits that need
to be enforced for the foreseeable future, this is not a very user
friendly behavior.

So, change the behavior to only apply limits that are enforced by
the cpufreq driver. Typically, these are just the absolute limits
of the HW and don't change very often.

Change-Id: I1ccfaa2d1ee4ea595f882485d359dbdb407a0176
Signed-off-by: Deepak Katragadda <dkatraga@codeaurora.org>