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: Mario Limonciello (AMD) <superm1@kernel.org>
Signed-off-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Signed-off-by: Mario Limonciello (AMD) <superm1@kernel.org>

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 53b8173ff1834a39f64f6f9bf22bd9e31eb2a2b5..a068c4457a8f7bbebeb3c26435f0afb6f0d5aa9b 100644 (file)
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -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,
-                                     0U, false);
+       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 = {

diff --git a/drivers/cpufreq/amd-pstate.h b/drivers/cpufreq/amd-pstate.h
index 303da70b0afa71173f8119c71c0f3dc8914f3866..453adfb445f8ddd801278e422dbe6ca8b347ebbb 100644 (file)
--- a/drivers/cpufreq/amd-pstate.h
+++ b/drivers/cpufreq/amd-pstate.h
@@ -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;