cpufreq: powernv: Add sysfs attributes to show throttle stats

Create sysfs attributes to export throttle information in
/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats directory. The
newly added sysfs files are as follows:

 1)/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/turbo_stat
 2)/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/sub-turbo_stat
 3)/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/unthrottle
 4)/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/powercap
 5)/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/overtemp
 6)/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/supply_fault
 7)/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/overcurrent
 8)/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/occ_reset

Detailed explanation of each attribute is added to
Documentation/ABI/testing/sysfs-devices-system-cpu

Signed-off-by: Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 72 insertions, 2 deletions

diff --git a/drivers/cpufreq/powernv-cpufreq.c b/drivers/cpufreq/powernv-cpufreq.c
index a00bcc2cef09..39ac78c94be0 100644
--- a/drivers/cpufreq/powernv-cpufreq.c
+++ b/drivers/cpufreq/powernv-cpufreq.c
@@ -54,6 +54,16 @@ static const char * const throttle_reason[] = {
         "OCC Reset"
 };
 
+enum throttle_reason_type {
+        NO_THROTTLE = 0,
+        POWERCAP,
+        CPU_OVERTEMP,
+        POWER_SUPPLY_FAILURE,
+        OVERCURRENT,
+        OCC_RESET_THROTTLE,
+        OCC_MAX_REASON
+};
+
 static struct chip {
         unsigned int id;
         bool throttled;
@@ -61,6 +71,9 @@ static struct chip {
         u8 throttle_reason;
         cpumask_t mask;
         struct work_struct throttle;
+        int throttle_turbo;
+        int throttle_sub_turbo;
+        int reason[OCC_MAX_REASON];
 } *chips;
 
 static int nr_chips;
@@ -196,6 +209,42 @@ static struct freq_attr *powernv_cpu_freq_attr[] = {
         NULL,
 };
 
+#define throttle_attr(name, member)                                     \
+static ssize_t name##_show(struct cpufreq_policy *policy, char *buf)    \
+{                                                                       \
+        struct chip *chip = per_cpu(chip_info, policy->cpu);            \
+                                                                        \
+        return sprintf(buf, "%u\n", chip->member);                      \
+}                                                                       \
+                                                                        \
+static struct freq_attr throttle_attr_##name = __ATTR_RO(name)          \
+
+throttle_attr(unthrottle, reason[NO_THROTTLE]);
+throttle_attr(powercap, reason[POWERCAP]);
+throttle_attr(overtemp, reason[CPU_OVERTEMP]);
+throttle_attr(supply_fault, reason[POWER_SUPPLY_FAILURE]);
+throttle_attr(overcurrent, reason[OVERCURRENT]);
+throttle_attr(occ_reset, reason[OCC_RESET_THROTTLE]);
+throttle_attr(turbo_stat, throttle_turbo);
+throttle_attr(sub_turbo_stat, throttle_sub_turbo);
+
+static struct attribute *throttle_attrs[] = {
+        &throttle_attr_unthrottle.attr,
+        &throttle_attr_powercap.attr,
+        &throttle_attr_overtemp.attr,
+        &throttle_attr_supply_fault.attr,
+        &throttle_attr_overcurrent.attr,
+        &throttle_attr_occ_reset.attr,
+        &throttle_attr_turbo_stat.attr,
+        &throttle_attr_sub_turbo_stat.attr,
+        NULL,
+};
+
+static const struct attribute_group throttle_attr_grp = {
+        .name   = "throttle_stats",
+        .attrs  = throttle_attrs,
+};
+
 /* Helper routines */
 
 /* Access helpers to power mgt SPR */
@@ -338,10 +387,14 @@ static void powernv_cpufreq_throttle_check(void *data)
                 if (chip->throttled)
                         goto next;
                 chip->throttled = true;
-                if (pmsr_pmax < powernv_pstate_info.nominal)
+                if (pmsr_pmax < powernv_pstate_info.nominal) {
                         pr_warn_once("CPU %d on Chip %u has Pmax reduced below nominal frequency (%d < %d)\n",
                                      cpu, chip->id, pmsr_pmax,
                                      powernv_pstate_info.nominal);
+                        chip->throttle_sub_turbo++;
+                } else {
+                        chip->throttle_turbo++;
+                }
                 trace_powernv_throttle(chip->id,
                                       throttle_reason[chip->throttle_reason],
                                       pmsr_pmax);
@@ -408,6 +461,21 @@ static int powernv_cpufreq_cpu_init(struct cpufreq_policy *policy)
         for (i = 0; i < threads_per_core; i++)
                 cpumask_set_cpu(base + i, policy->cpus);
 
+        if (!policy->driver_data) {
+                int ret;
+
+                ret = sysfs_create_group(&policy->kobj, &throttle_attr_grp);
+                if (ret) {
+                        pr_info("Failed to create throttle stats directory for cpu %d\n",
+                                policy->cpu);
+                        return ret;
+                }
+                /*
+                 * policy->driver_data is used as a flag for one-time
+                 * creation of throttle sysfs files.
+                 */
+                policy->driver_data = policy;
+        }
         return cpufreq_table_validate_and_show(policy, powernv_freqs);
 }
 
@@ -514,8 +582,10 @@ static int powernv_cpufreq_occ_msg(struct notifier_block *nb,
                                 break;
 
                 if (omsg.throttle_status >= 0 &&
-                    omsg.throttle_status <= OCC_MAX_THROTTLE_STATUS)
+                    omsg.throttle_status <= OCC_MAX_THROTTLE_STATUS) {
                         chips[i].throttle_reason = omsg.throttle_status;
+                        chips[i].reason[omsg.throttle_status]++;
+                }
 
                 if (!omsg.throttle_status)
                         chips[i].restore = true;