Commit b9f103d0 authored by Gautham R. Shenoy's avatar Gautham R. Shenoy Committed by Mario Limonciello (AMD)
Browse files

amd-pstate: Add sysfs support for floor_freq and floor_count 



When Floor Performance feature is supported by the platform, expose
two sysfs files:

   * amd_pstate_floor_freq to allow userspace to request the floor
     frequency for each CPU.

   * amd_pstate_floor_count which advertises the number of distinct
     levels of floor frequencies supported on this platform.

Reset the floor_perf to bios_floor_perf in the suspend, offline, and
exit paths, and restore the value to the cached user-request
floor_freq on the resume and online paths mirroring how bios_min_perf
is handled for MSR_AMD_CPPC_REQ.

Reviewed-by: default avatarMario Limonciello (AMD) <superm1@kernel.org>
Signed-off-by: default avatarGautham R. Shenoy <gautham.shenoy@amd.com>
Signed-off-by: default avatarMario Limonciello (AMD) <superm1@kernel.org>
parent 97838281

drivers/cpufreq/amd-pstate.c

+87 −6
Original line number Diff line number Diff line
@@ -383,8 +383,10 @@ static int amd_pstate_init_floor_perf(struct cpufreq_policy *policy) 
			return ret;

	}



	cpudata->bios_floor_perf = floor_perf;



	cpudata->bios_floor_perf = floor_perf;

	cpudata->floor_freq = perf_to_freq(cpudata->perf, cpudata->nominal_freq,

					   floor_perf);

	return 0;

}
@@ -1288,6 +1290,46 @@ static ssize_t show_energy_performance_preference( 
	return sysfs_emit(buf, "%s\n", energy_perf_strings[preference]);

}



static ssize_t store_amd_pstate_floor_freq(struct cpufreq_policy *policy,

					   const char *buf, size_t count)

{

	struct amd_cpudata *cpudata = policy->driver_data;

	union perf_cached perf = READ_ONCE(cpudata->perf);

	unsigned int freq;

	u8 floor_perf;

	int ret;



	ret = kstrtouint(buf, 0, &freq);

	if (ret)

		return ret;



	if (freq < policy->cpuinfo.min_freq || freq > policy->max)

		return -EINVAL;



	floor_perf = freq_to_perf(perf, cpudata->nominal_freq, freq);

	ret = amd_pstate_set_floor_perf(policy, floor_perf);



	if (!ret)

		cpudata->floor_freq = freq;



	return ret ?: count;

}



static ssize_t show_amd_pstate_floor_freq(struct cpufreq_policy *policy, char *buf)

{

	struct amd_cpudata *cpudata = policy->driver_data;



	return sysfs_emit(buf, "%u\n", cpudata->floor_freq);

}



static ssize_t show_amd_pstate_floor_count(struct cpufreq_policy *policy, char *buf)

{

	struct amd_cpudata *cpudata = policy->driver_data;

	u8 count = cpudata->floor_perf_cnt;



	return sysfs_emit(buf, "%u\n", count);

}



cpufreq_freq_attr_ro(amd_pstate_max_freq);

cpufreq_freq_attr_ro(amd_pstate_lowest_nonlinear_freq);
@@ -1296,6 +1338,8 @@ cpufreq_freq_attr_ro(amd_pstate_prefcore_ranking); 
cpufreq_freq_attr_ro(amd_pstate_hw_prefcore);

cpufreq_freq_attr_rw(energy_performance_preference);

cpufreq_freq_attr_ro(energy_performance_available_preferences);

cpufreq_freq_attr_rw(amd_pstate_floor_freq);

cpufreq_freq_attr_ro(amd_pstate_floor_count);



struct freq_attr_visibility {

	struct freq_attr *attr;
@@ -1320,6 +1364,12 @@ static bool epp_visibility(void) 
	return cppc_state == AMD_PSTATE_ACTIVE;

}



/* Determines whether amd_pstate_floor_freq related attributes should be visible */

static bool floor_freq_visibility(void)

{

	return cpu_feature_enabled(X86_FEATURE_CPPC_PERF_PRIO);

}



static struct freq_attr_visibility amd_pstate_attr_visibility[] = {

	{&amd_pstate_max_freq, always_visible},

	{&amd_pstate_lowest_nonlinear_freq, always_visible},
@@ -1328,6 +1378,8 @@ static struct freq_attr_visibility amd_pstate_attr_visibility[] = { 
	{&amd_pstate_hw_prefcore, prefcore_visibility},

	{&energy_performance_preference, epp_visibility},

	{&energy_performance_available_preferences, epp_visibility},

	{&amd_pstate_floor_freq, floor_freq_visibility},

	{&amd_pstate_floor_count, floor_freq_visibility},

};



static struct freq_attr **get_freq_attrs(void)
@@ -1748,24 +1800,39 @@ static int amd_pstate_epp_set_policy(struct cpufreq_policy *policy) 


static int amd_pstate_cpu_online(struct cpufreq_policy *policy)

{

	return amd_pstate_cppc_enable(policy);

	struct amd_cpudata *cpudata = policy->driver_data;

	union perf_cached perf = READ_ONCE(cpudata->perf);

	u8 cached_floor_perf;

	int ret;



	ret = amd_pstate_cppc_enable(policy);

	if (ret)

		return ret;



	cached_floor_perf = freq_to_perf(perf, cpudata->nominal_freq, cpudata->floor_freq);

	return amd_pstate_set_floor_perf(policy, cached_floor_perf);

}



static int amd_pstate_cpu_offline(struct cpufreq_policy *policy)

{

	struct amd_cpudata *cpudata = policy->driver_data;

	union perf_cached perf = READ_ONCE(cpudata->perf);

	int ret;



	/*

	 * Reset CPPC_REQ MSR to the BIOS value, this will allow us to retain the BIOS specified

	 * min_perf value across kexec reboots. If this CPU is just onlined normally after this, the

	 * limits, epp and desired perf will get reset to the cached values in cpudata struct

	 */

	return amd_pstate_update_perf(policy, perf.bios_min_perf,

	ret = amd_pstate_update_perf(policy, perf.bios_min_perf,

				     FIELD_GET(AMD_CPPC_DES_PERF_MASK, cpudata->cppc_req_cached),

				     FIELD_GET(AMD_CPPC_MAX_PERF_MASK, cpudata->cppc_req_cached),

				     FIELD_GET(AMD_CPPC_EPP_PERF_MASK, cpudata->cppc_req_cached),

				     false);

	if (ret)

		return ret;



	return amd_pstate_set_floor_perf(policy, cpudata->bios_floor_perf);

}



static int amd_pstate_suspend(struct cpufreq_policy *policy)
@@ -1787,6 +1854,10 @@ static int amd_pstate_suspend(struct cpufreq_policy *policy) 
	if (ret)

		return ret;



	ret = amd_pstate_set_floor_perf(policy, cpudata->bios_floor_perf);

	if (ret)

		return ret;



	/* set this flag to avoid setting core offline*/

	cpudata->suspended = true;
@@ -1798,15 +1869,24 @@ static int amd_pstate_resume(struct cpufreq_policy *policy) 
	struct amd_cpudata *cpudata = policy->driver_data;

	union perf_cached perf = READ_ONCE(cpudata->perf);

	int cur_perf = freq_to_perf(perf, cpudata->nominal_freq, policy->cur);

	u8 cached_floor_perf;

	int ret;



	/* Set CPPC_REQ to last sane value until the governor updates it */

	return amd_pstate_update_perf(policy, perf.min_limit_perf, cur_perf, perf.max_limit_perf,

	ret = amd_pstate_update_perf(policy, perf.min_limit_perf, cur_perf, perf.max_limit_perf,

				     0U, false);

	if (ret)

		return ret;



	cached_floor_perf = freq_to_perf(perf, cpudata->nominal_freq, cpudata->floor_freq);

	return amd_pstate_set_floor_perf(policy, cached_floor_perf);

}



static int amd_pstate_epp_resume(struct cpufreq_policy *policy)

{

	struct amd_cpudata *cpudata = policy->driver_data;

	union perf_cached perf = READ_ONCE(cpudata->perf);

	u8 cached_floor_perf;



	if (cpudata->suspended) {

		int ret;
@@ -1819,7 +1899,8 @@ static int amd_pstate_epp_resume(struct cpufreq_policy *policy) 
		cpudata->suspended = false;

	}



	return 0;

	cached_floor_perf = freq_to_perf(perf, cpudata->nominal_freq, cpudata->floor_freq);

	return amd_pstate_set_floor_perf(policy, cached_floor_perf);

}



static struct cpufreq_driver amd_pstate_driver = {

drivers/cpufreq/amd-pstate.h

+2 −0
Original line number Diff line number Diff line
@@ -74,6 +74,7 @@ struct amd_aperf_mperf { 
 * @max_limit_freq: Cached value of policy->max (in khz)

 * @nominal_freq: the frequency (in khz) that mapped to nominal_perf

 * @lowest_nonlinear_freq: the frequency (in khz) that mapped to lowest_nonlinear_perf

 * @floor_freq: Cached value of the user requested floor_freq

 * @cur: Difference of Aperf/Mperf/tsc count between last and current sample

 * @prev: Last Aperf/Mperf/tsc count value read from register

 * @freq: current cpu frequency value (in khz)
@@ -103,6 +104,7 @@ struct amd_cpudata { 
	u32	max_limit_freq;

	u32	nominal_freq;

	u32	lowest_nonlinear_freq;

	u32	floor_freq;



	struct amd_aperf_mperf cur;

	struct amd_aperf_mperf prev;