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Commit 52b3672c authored by Zhen Han's avatar Zhen Han Committed by Rafael J. Wysocki
Browse files

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: default avatarZhen Han <zhen.han@intel.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 7f634489

drivers/powercap/intel_rapl.c

+97 −0
Original line number Diff line number Diff line
@@ -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();

}