cpufreq: tegra194: add online/offline hooks

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 <viresh.kumar@linaro.org>
Signed-off-by: Sumit Gupta <sumitg@nvidia.com>
Link: https://lore.kernel.org/lkml/20230816033402.3abmugb5goypvllm@vireshk-i7/
[ Viresh: Fixed rebase conflict ]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

diff --git a/drivers/cpufreq/tegra194-cpufreq.c b/drivers/cpufreq/tegra194-cpufreq.c
index c90b304..88df7e5 100644 (file)
--- a/drivers/cpufreq/tegra194-cpufreq.c
+++ b/drivers/cpufreq/tegra194-cpufreq.c
@@ -508,6 +508,21 @@ static int tegra194_cpufreq_init(struct cpufreq_policy *policy)
        return 0;
 }
 
+static int tegra194_cpufreq_online(struct cpufreq_policy *policy)
+{
+       /* We did light-weight tear down earlier, nothing to do here */
+       return 0;
+}
+
+static int tegra194_cpufreq_offline(struct cpufreq_policy *policy)
+{
+       /*
+        * Preserve policy->driver_data and don't free resources on light-weight
+        * tear down.
+        */
+       return 0;
+}
+
 static int tegra194_cpufreq_set_target(struct cpufreq_policy *policy,
                                       unsigned int index)
 {
@@ -535,6 +550,8 @@ static struct cpufreq_driver tegra194_cpufreq_driver = {
        .target_index = tegra194_cpufreq_set_target,
        .get = tegra194_get_speed,
        .init = tegra194_cpufreq_init,
+       .online = tegra194_cpufreq_online,
+       .offline = tegra194_cpufreq_offline,
        .attr = cpufreq_generic_attr,
 };