linux-toradex.git/drivers/cpufreq, branch v6.6-rc3

cpufreq: Support per-policy performance boost

2023-08-29T18:51:40+00:00

The boost control currently applies to the whole system.  However, users
may prefer to boost a subset of cores in order to provide prioritized
performance to workloads running on the boosted cores.

Enable per-policy boost by adding a 'boost' sysfs interface under each
policy path.  This can be found at:

	/sys/devices/system/cpu/cpufreq/policy<*>/boost

Same to the global boost switch, writing 1/0 to the per-policy 'boost'
enables/disables boost on a cpufreq policy respectively.

The user view of global and per-policy boost controls should be:

1. Enabling global boost initially enables boost on all policies, and
per-policy boost can then be enabled or disabled individually, given that
the platform does support so.

2. Disabling global boost makes the per-policy boost interface illegal.

Signed-off-by: Jie Zhan 
Reviewed-by: Wei Xu 
Acked-by: Viresh Kumar 
Signed-off-by: Rafael J. Wysocki

cpufreq: pcc: Fix the potentinal scheduling delays in target_index()

2023-08-29T18:41:29+00:00

pcc_cpufreq_target():
	cpufreq_freq_transition_begin();
	spin_lock(&pcc_lock);
	[critical section]
	cpufreq_freq_transition_end();
	spin_unlock(&pcc_lock);

Above code has a performance issue, consider that Task0 executes
'cpufreq_freq_transition_end()' to wake Task1 and preempted imediatedly
without releasing 'pcc_lock', then Task1 needs to wait for Task0 to
release 'pcc_lock'. In the worst case, this locking order can result in
Task1 wasting two scheduling rounds before it can enter the critical
section.

Signed-off-by: Liao Chang 
Acked-by: Viresh Kumar 
Signed-off-by: Rafael J. Wysocki

cpufreq: governor: Free dbs_data directly when gov->init() fails

2023-08-29T18:21:35+00:00

Due to the kobject embedded in the dbs_data doest not has a release()
method yet, it needs to use kfree() to free dbs_data directly when
governor fails to allocate the tunner field of dbs_data.

Signed-off-by: Liao Chang 
Acked-by: Viresh Kumar 
Signed-off-by: Rafael J. Wysocki

cpufreq: Fix the race condition while updating the transition_task of policy

2023-08-29T18:19:31+00:00

The field 'transition_task' of policy structure is used to track the
task which is performing the frequency transition. Using this field to
print a warning once detect a case where the same task is calling
_begin() again before completing the preivous frequency transition via
the _end().

However, there is a potential race condition in _end() and _begin() APIs
while updating the field 'transition_task' of policy, the scenario is
depicted below:

             Task A                            Task B

        /* 1st freq transition */
        Invoke _begin() {
                ...
                ...
        }
                                        /* 2nd freq transition */
                                        Invoke _begin() {
                                                ... //waiting for A to
                                                ... //clear
                                                ... //transition_ongoing
                                                ... //in _end() for
                                                ... //the 1st transition
                                                        |
        Change the frequency                            |
                                                        |
        Invoke _end() {                                 |
                ...                                     |
                ...                                     |
                transition_ongoing = false;             V
                                                transition_ongoing = true;
                                                transition_task = current;
                transition_task = NULL;
                ... //A overwrites the task
                ... //performing the transition
                ... //result in error warning.
        }

To fix this race condition, the transition_lock of policy structure is
now acquired before updating policy structure in _end() API. Which ensure
that only one task can update the 'transition_task' field at a time.

Link: https://lore.kernel.org/all/b3c61d8a-d52d-3136-fbf0-d1de9f1ba411@huawei.com/
Fixes: ca654dc3a93d ("cpufreq: Catch double invocations of cpufreq_freq_transition_begin/end")
Signed-off-by: Liao Chang 
Acked-by: Viresh Kumar 
Signed-off-by: Rafael J. Wysocki

cpufreq: Avoid printing kernel addresses in cpufreq_resume()

2023-08-29T18:17:24+00:00

The pointer value of policy and driver structure are currently printed
in the error messages of cpufreq_resume(), this is not recommended and
helpful.

In order to be consistent with the error message in cpufreq_suspend()
and easier to understand, print the name of driver strcture and the
manage CPU of policy structure individually in the error messages of
cpufreq_resume().

Link: https://lore.kernel.org/all/b7be717c-41d8-bbbf-3e97-3799948ab757@huawei.com
Signed-off-by: Liao Chang 
Acked-by: Viresh Kumar 
Signed-off-by: Rafael J. Wysocki

Merge tag 'cpufreq-arm-updates-6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/vireshk/pm

2023-08-28T12:12:05+00:00

Pull ARM cpufreq updates for 6.6 from Viresh Kumar:

"- Migrate various platforms to use remove callback returning void
(Yangtao Li).

- Add online/offline/exit hooks for Tegra driver (Sumit Gupta).

- Explicitly include correct DT includes (Rob Herring).

- Frequency domain updates for qcom-hw driver (Neil Armstrong).

- Modify AMD pstate driver return the highest_perf value (Meng Li).

- Generic cleanups for cppc, mediatek and powernow driver (Liao Chang
and Konrad Dybcio).

- Add more platforms to cpufreq-arm driver's blocklist (AngeloGioacchino
Del Regno and Konrad Dybcio).

- brcmstb-avs-cpufreq: Fix -Warray-bounds bug (Gustavo A. R. Silva)."

* tag 'cpufreq-arm-updates-6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/vireshk/pm: (33 commits)
cpufreq: tegra194: remove opp table in exit hook
cpufreq: powernow-k8: Use related_cpus instead of cpus in driver.exit()
cpufreq: tegra194: add online/offline hooks
cpufreq: qcom-cpufreq-hw: add support for 4 freq domains
dt-bindings: cpufreq: qcom-hw: add a 4th frequency domain
cpufreq: cppc: Set fie_disabled to FIE_DISABLED if fails to create kworker_fie
cpufreq: cppc: cppc_cpufreq_get_rate() returns zero in all error cases.
cpufreq: Prefer to print cpuid in MIN/MAX QoS register error message
cpufreq: amd-pstate-ut: Modify the function to get the highest_perf value
cpufreq: mediatek-hw: Remove unused define
cpufreq: blocklist more Qualcomm platforms in cpufreq-dt-platdev
cpufreq: brcmstb-avs-cpufreq: Fix -Warray-bounds bug
cpufreq: blocklist MSM8998 in cpufreq-dt-platdev
cpufreq: omap: Convert to platform remove callback returning void
cpufreq: qoriq: Convert to platform remove callback returning void
cpufreq: acpi: Convert to platform remove callback returning void
cpufreq: tegra186: Convert to platform remove callback returning void
cpufreq: qcom-nvmem: Convert to platform remove callback returning void
cpufreq: kirkwood: Convert to platform remove callback returning void
cpufreq: pcc-cpufreq: Convert to platform remove callback returning void
...

cpufreq: tegra194: remove opp table in exit hook

2023-08-28T10:15:24+00:00

Add exit hook and remove OPP table when the device gets unregistered.
This will fix the error messages when the CPU FREQ driver module is
removed and then re-inserted. It also fixes these messages while
onlining the first CPU from a policy whose all CPU's were previously
offlined.

 debugfs: File 'cpu5' in directory 'opp' already present!
 debugfs: File 'cpu6' in directory 'opp' already present!
 debugfs: File 'cpu7' in directory 'opp' already present!

Fixes: f41e1442ac5b ("cpufreq: tegra194: add OPP support and set bandwidth")
Signed-off-by: Sumit Gupta 
[ Viresh: Dropped irrelevant change from it ]
Signed-off-by: Viresh Kumar

cpufreq: powernow-k8: Use related_cpus instead of cpus in driver.exit()

2023-08-28T06:57:30+00:00

Since the 'cpus' field of policy structure will become empty in the
cpufreq core API, it is better to use 'related_cpus' in the exit()
callback of driver.

Fixes: c3274763bfc3 ("cpufreq: powernow-k8: Initialize per-cpu data-structures properly")
Signed-off-by: Liao Chang 
Signed-off-by: Viresh Kumar

cpufreq: tegra194: add online/offline hooks

2023-08-28T06:13:54+00:00

Implement the light-weight tear down and bring up helpers to reduce the
amount of work to do on CPU offline/online operation.
This change helps to make the hotplugging paths much faster.

Suggested-by: Viresh Kumar 
Signed-off-by: Sumit Gupta 
Link: https://lore.kernel.org/lkml/20230816033402.3abmugb5goypvllm@vireshk-i7/
[ Viresh: Fixed rebase conflict ]
Signed-off-by: Viresh Kumar

cpufreq: qcom-cpufreq-hw: add support for 4 freq domains

2023-08-23T15:01:08+00:00

Add support for up to 4 frequency domains as used on new
platforms.

Signed-off-by: Neil Armstrong 
Acked-by: Konrad Dybcio 
Signed-off-by: Viresh Kumar