powercap: add suspend and resume mechanism for SOC power limit

PL1 and PL2 could be throlled or de-throttled by
Thermal management to control SOC temperature.

However, currently, their value will be reset to default value
after once system suspend and resume.

Add pm_notifier to save PL1, PL2 before system suspect and restore
PL1, PL2 after system resume.

Signed-off-by: Zhen Han <zhen.han@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/powercap/intel_rapl.c b/drivers/powercap/intel_rapl.c
index d1694f1def7278d17249bbbc23e0a64b3704ba5d..0188cff98cdd160b2cd46aec33c4986841cc3fd6 100644 (file)
--- a/drivers/powercap/intel_rapl.c
+++ b/drivers/powercap/intel_rapl.c
@@ -29,6 +29,7 @@
 #include <linux/sysfs.h>
 #include <linux/cpu.h>
 #include <linux/powercap.h>
+#include <linux/suspend.h>
 #include <asm/iosf_mbi.h>
 
 #include <asm/processor.h>
@@ -155,6 +156,7 @@ struct rapl_power_limit {
        int prim_id; /* primitive ID used to enable */
        struct rapl_domain *domain;
        const char *name;
+       u64 last_power_limit;
 };
 
 static const char pl1_name[] = "long_term";
@@ -1533,6 +1535,92 @@ static int rapl_cpu_down_prep(unsigned int cpu)
 
 static enum cpuhp_state pcap_rapl_online;
 
+static void power_limit_state_save(void)
+{
+       struct rapl_package *rp;
+       struct rapl_domain *rd;
+       int nr_pl, ret, i;
+
+       get_online_cpus();
+       list_for_each_entry(rp, &rapl_packages, plist) {
+               if (!rp->power_zone)
+                       continue;
+               rd = power_zone_to_rapl_domain(rp->power_zone);
+               nr_pl = find_nr_power_limit(rd);
+               for (i = 0; i < nr_pl; i++) {
+                       switch (rd->rpl[i].prim_id) {
+                       case PL1_ENABLE:
+                               ret = rapl_read_data_raw(rd,
+                                               POWER_LIMIT1,
+                                               true,
+                                               &rd->rpl[i].last_power_limit);
+                               if (ret)
+                                       rd->rpl[i].last_power_limit = 0;
+                               break;
+                       case PL2_ENABLE:
+                               ret = rapl_read_data_raw(rd,
+                                               POWER_LIMIT2,
+                                               true,
+                                               &rd->rpl[i].last_power_limit);
+                               if (ret)
+                                       rd->rpl[i].last_power_limit = 0;
+                               break;
+                       }
+               }
+       }
+       put_online_cpus();
+}
+
+static void power_limit_state_restore(void)
+{
+       struct rapl_package *rp;
+       struct rapl_domain *rd;
+       int nr_pl, i;
+
+       get_online_cpus();
+       list_for_each_entry(rp, &rapl_packages, plist) {
+               if (!rp->power_zone)
+                       continue;
+               rd = power_zone_to_rapl_domain(rp->power_zone);
+               nr_pl = find_nr_power_limit(rd);
+               for (i = 0; i < nr_pl; i++) {
+                       switch (rd->rpl[i].prim_id) {
+                       case PL1_ENABLE:
+                               if (rd->rpl[i].last_power_limit)
+                                       rapl_write_data_raw(rd,
+                                               POWER_LIMIT1,
+                                               rd->rpl[i].last_power_limit);
+                               break;
+                       case PL2_ENABLE:
+                               if (rd->rpl[i].last_power_limit)
+                                       rapl_write_data_raw(rd,
+                                               POWER_LIMIT2,
+                                               rd->rpl[i].last_power_limit);
+                               break;
+                       }
+               }
+       }
+       put_online_cpus();
+}
+
+static int rapl_pm_callback(struct notifier_block *nb,
+       unsigned long mode, void *_unused)
+{
+       switch (mode) {
+       case PM_SUSPEND_PREPARE:
+               power_limit_state_save();
+               break;
+       case PM_POST_SUSPEND:
+               power_limit_state_restore();
+               break;
+       }
+       return NOTIFY_OK;
+}
+
+static struct notifier_block rapl_pm_notifier = {
+       .notifier_call = rapl_pm_callback,
+};
+
 static int __init rapl_init(void)
 {
        const struct x86_cpu_id *id;
@@ -1560,8 +1648,16 @@ static int __init rapl_init(void)
 
        /* Don't bail out if PSys is not supported */
        rapl_register_psys();
+
+       ret = register_pm_notifier(&rapl_pm_notifier);
+       if (ret)
+               goto err_unreg_all;
+
        return 0;
 
+err_unreg_all:
+       cpuhp_remove_state(pcap_rapl_online);
+
 err_unreg:
        rapl_unregister_powercap();
        return ret;
@@ -1569,6 +1665,7 @@ static int __init rapl_init(void)
 
 static void __exit rapl_exit(void)
 {
+       unregister_pm_notifier(&rapl_pm_notifier);
        cpuhp_remove_state(pcap_rapl_online);
        rapl_unregister_powercap();
 }