cpufreq: Introduce a more generic way to set default per-policy boost flag

In cpufreq_online() of cpufreq.c, the per-policy boost flag is already
set to mirror the cpufreq_driver boost during init but using freq_table
to judge if the policy has boost frequency. There are two drawbacks to
this approach:

 1. It doesn't work for the cpufreq drivers that do not use a frequency
    table. For now, acpi-cpufreq and amd-pstate have to enable boost in
    policy initialization. And cppc_cpufreq never set policy to boost
    when going online no matter what the cpufreq_driver boost flag is.

 2. If the CPU goes offline when cpufreq_driver boost is enabled and
    then goes online when cpufreq_driver boost is disabled, the
    per-policy boost flag will incorrectly remain true.

Running set_boost at the end of the online process is a more generic way
for all cpufreq drivers.

Signed-off-by: Lifeng Zheng <[email protected]>
Link: https://patch.msgid.link/[email protected]
Acked-by: Viresh Kumar <[email protected]>
[ rjw: Changelog edits ]
Signed-off-by: Rafael J. Wysocki <[email protected]>

Author: Lifeng Zheng

drivers/cpufreq/cpufreq.c

@@ -1410,10 +1410,6 @@ static int cpufreq_online(unsigned int cpu)
 			goto out_free_policy;
 		}
 
-		/* Let the per-policy boost flag mirror the cpufreq_driver boost during init */
-		if (cpufreq_boost_enabled() && policy_has_boost_freq(policy))
-			policy->boost_enabled = true;
-
 		/*
 		 * The initialization has succeeded and the policy is online.
 		 * If there is a problem with its frequency table, take it
@@ -1574,6 +1570,18 @@ static int cpufreq_online(unsigned int cpu)
 	if (new_policy && cpufreq_thermal_control_enabled(cpufreq_driver))
 		policy->cdev = of_cpufreq_cooling_register(policy);
 
+	/* Let the per-policy boost flag mirror the cpufreq_driver boost during init */
+	if (policy->boost_enabled != cpufreq_boost_enabled()) {
+		policy->boost_enabled = cpufreq_boost_enabled();
+		ret = cpufreq_driver->set_boost(policy, policy->boost_enabled);
+		if (ret) {
+			/* If the set_boost fails, the online operation is not affected */
+			pr_info("%s: CPU%d: Cannot %s BOOST\n", __func__, policy->cpu,
+				policy->boost_enabled ? "enable" : "disable");
+			policy->boost_enabled = !policy->boost_enabled;
+		}
+	}
+
 	pr_debug("initialization complete\n");
 
 	return 0;