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Subject[PATCH 01/22 v2] cpufreq/acpi-cpufreq: Convert to hotplug state machine
Install the callbacks via the state machine.

Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: linux-pm@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
v1…v2: set msrs to NULL on error during init.

drivers/cpufreq/acpi-cpufreq.c | 92 ++++++++++++++++++++---------------------
1 file changed, 45 insertions(+), 47 deletions(-)

--- a/drivers/cpufreq/acpi-cpufreq.c
+++ b/drivers/cpufreq/acpi-cpufreq.c
@@ -536,46 +536,33 @@ static void free_acpi_perf_data(void)
free_percpu(acpi_perf_data);
}

-static int boost_notify(struct notifier_block *nb, unsigned long action,
- void *hcpu)
+static int cpufreq_boost_online(unsigned int cpu)
{
- unsigned cpu = (long)hcpu;
const struct cpumask *cpumask;

cpumask = get_cpu_mask(cpu);
-
/*
- * Clear the boost-disable bit on the CPU_DOWN path so that
- * this cpu cannot block the remaining ones from boosting. On
- * the CPU_UP path we simply keep the boost-disable flag in
- * sync with the current global state.
+ * On the CPU_UP path we simply keep the boost-disable flag
+ * in sync with the current global state.
*/
+ boost_set_msrs(acpi_cpufreq_driver.boost_enabled, cpumask);
+ return 0;
+}

- switch (action) {
- case CPU_DOWN_FAILED:
- case CPU_DOWN_FAILED_FROZEN:
- case CPU_ONLINE:
- case CPU_ONLINE_FROZEN:
- boost_set_msrs(acpi_cpufreq_driver.boost_enabled, cpumask);
- break;
-
- case CPU_DOWN_PREPARE:
- case CPU_DOWN_PREPARE_FROZEN:
- boost_set_msrs(1, cpumask);
- break;
+static int cpufreq_boost_down_prep(unsigned int cpu)
+{
+ const struct cpumask *cpumask;

- default:
- break;
- }
+ cpumask = get_cpu_mask(cpu);

- return NOTIFY_OK;
+ /*
+ * Clear the boost-disable bit on the CPU_DOWN path so that
+ * this cpu cannot block the remaining ones from boosting.
+ */
+ boost_set_msrs(1, cpumask);
+ return 0;
}

-
-static struct notifier_block boost_nb = {
- .notifier_call = boost_notify,
-};
-
/*
* acpi_cpufreq_early_init - initialize ACPI P-States library
*
@@ -922,37 +909,48 @@ static struct cpufreq_driver acpi_cpufre
.attr = acpi_cpufreq_attr,
};

+static enum cpuhp_state acpi_cpufreq_online;
+
static void __init acpi_cpufreq_boost_init(void)
{
- if (boot_cpu_has(X86_FEATURE_CPB) || boot_cpu_has(X86_FEATURE_IDA)) {
- msrs = msrs_alloc();
+ int ret;

- if (!msrs)
- return;
+ if (!(boot_cpu_has(X86_FEATURE_CPB) || boot_cpu_has(X86_FEATURE_IDA)))
+ return;

- acpi_cpufreq_driver.set_boost = set_boost;
- acpi_cpufreq_driver.boost_enabled = boost_state(0);
+ msrs = msrs_alloc();

- cpu_notifier_register_begin();
+ if (!msrs)
+ return;

- /* Force all MSRs to the same value */
- boost_set_msrs(acpi_cpufreq_driver.boost_enabled,
- cpu_online_mask);
+ acpi_cpufreq_driver.set_boost = set_boost;
+ acpi_cpufreq_driver.boost_enabled = boost_state(0);

- __register_cpu_notifier(&boost_nb);
-
- cpu_notifier_register_done();
+ /*
+ * This calls the online callback on all online cpu and forces all
+ * MSRs to the same value.
+ */
+ ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "cpufreq/acpi:online",
+ cpufreq_boost_online, cpufreq_boost_down_prep);
+ if (ret < 0) {
+ pr_err("acpi_cpufreq: failed to register hotplug callbacks\n");
+ msrs_free(msrs);
+ msrs = NULL;
+ return;
}
+ acpi_cpufreq_online = ret;
}

static void acpi_cpufreq_boost_exit(void)
{
- if (msrs) {
- unregister_cpu_notifier(&boost_nb);
+ if (!msrs)
+ return;

- msrs_free(msrs);
- msrs = NULL;
- }
+ if (acpi_cpufreq_online >= 0)
+ cpuhp_remove_state_nocalls(acpi_cpufreq_online);
+
+ msrs_free(msrs);
+ msrs = NULL;
}

static int __init acpi_cpufreq_init(void)
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