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	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * POWERNV cpufreq driver for the IBM POWER processors
  *
  * (C) Copyright IBM 2014
  *
  * Author: Vaidyanathan Srinivasan <svaidy at linux.vnet.ibm.com>
  */
 
 #define pr_fmt(fmt) "powernv-cpufreq: " fmt
 
 #include <linux/kernel.h>
 #include <linux/sysfs.h>
 #include <linux/cpumask.h>
 #include <linux/module.h>
 #include <linux/cpufreq.h>
 #include <linux/smp.h>
 #include <linux/of.h>
 #include <linux/reboot.h>
 #include <linux/slab.h>
 #include <linux/cpu.h>
 #include <linux/hashtable.h>
 #include <trace/events/power.h>
 
 #include <asm/cputhreads.h>
 #include <asm/firmware.h>
 #include <asm/reg.h>
 #include <asm/smp.h> /* Required for cpu_sibling_mask() in UP configs */
 #include <asm/opal.h>
 #include <linux/timer.h>
 
 #define POWERNV_MAX_PSTATES_ORDER  8
 #define POWERNV_MAX_PSTATES (1UL << (POWERNV_MAX_PSTATES_ORDER))
 #define PMSR_PSAFE_ENABLE   (1UL << 30)
 #define PMSR_SPR_EM_DISABLE (1UL << 31)
 #define MAX_PSTATE_SHIFT    32
 #define LPSTATE_SHIFT       48
 #define GPSTATE_SHIFT       56
 #define MAX_NR_CHIPS        32
 
 #define MAX_RAMP_DOWN_TIME              5120
 /*
  * On an idle system we want the global pstate to ramp-down from max value to
  * min over a span of ~5 secs. Also we want it to initially ramp-down slowly and
  * then ramp-down rapidly later on.
  *
  * This gives a percentage rampdown for time elapsed in milliseconds.
  * ramp_down_percentage = ((ms * ms) >> 18)
  *          ~= 3.8 * (sec * sec)
  *
  * At 0 ms  ramp_down_percent = 0
  * At 5120 ms   ramp_down_percent = 100
  */
 #define ramp_down_percent(time)     ((time * time) >> 18)
 
 /* Interval after which the timer is queued to bring down global pstate */
 #define GPSTATE_TIMER_INTERVAL              2000
 
 /**
  * struct global_pstate_info -  Per policy data structure to maintain history of
  *              global pstates
  * @highest_lpstate_idx:    The local pstate index from which we are
  *              ramping down
  * @elapsed_time:       Time in ms spent in ramping down from
  *              highest_lpstate_idx
  * @last_sampled_time:      Time from boot in ms when global pstates were
  *              last set
  * @last_lpstate_idx:       Last set value of local pstate and global
  * @last_gpstate_idx:       pstate in terms of cpufreq table index
  * @timer:          Is used for ramping down if cpu goes idle for
  *              a long time with global pstate held high
  * @gpstate_lock:       A spinlock to maintain synchronization between
  *              routines called by the timer handler and
  *              governer's target_index calls
  * @policy:         Associated CPUFreq policy
  */
 struct global_pstate_info {
     int highest_lpstate_idx;
     unsigned int elapsed_time;
     unsigned int last_sampled_time;
     int last_lpstate_idx;
     int last_gpstate_idx;
     spinlock_t gpstate_lock;
     struct timer_list timer;
     struct cpufreq_policy *policy;
 };
 
 static struct cpufreq_frequency_table powernv_freqs[POWERNV_MAX_PSTATES+1];
 
 static DEFINE_HASHTABLE(pstate_revmap, POWERNV_MAX_PSTATES_ORDER);
 /**
  * struct pstate_idx_revmap_data: Entry in the hashmap pstate_revmap
  *                indexed by a function of pstate id.
  *
  * @pstate_id: pstate id for this entry.
  *
  * @cpufreq_table_idx: Index into the powernv_freqs
  *             cpufreq_frequency_table for frequency
  *             corresponding to pstate_id.
  *
  * @hentry: hlist_node that hooks this entry into the pstate_revmap
  *      hashtable
  */
 struct pstate_idx_revmap_data {
     u8 pstate_id;
     unsigned int cpufreq_table_idx;
     struct hlist_node hentry;
 };
 
 static bool rebooting, throttled, occ_reset;
 
 static const char * const throttle_reason[] = {
     "No throttling",
     "Power Cap",
     "Processor Over Temperature",
     "Power Supply Failure",
     "Over Current",
     "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;
     bool restore;
     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;
 static DEFINE_PER_CPU(struct chip *, chip_info);
 
 /*
  * Note:
  * The set of pstates consists of contiguous integers.
  * powernv_pstate_info stores the index of the frequency table for
  * max, min and nominal frequencies. It also stores number of
  * available frequencies.
  *
  * powernv_pstate_info.nominal indicates the index to the highest
  * non-turbo frequency.
  */
 static struct powernv_pstate_info {
     unsigned int min;
     unsigned int max;
     unsigned int nominal;
     unsigned int nr_pstates;
     bool wof_enabled;
 } powernv_pstate_info;
 
 static inline u8 extract_pstate(u64 pmsr_val, unsigned int shift)
 {
     return ((pmsr_val >> shift) & 0xFF);
 }
 
 #define extract_local_pstate(x) extract_pstate(x, LPSTATE_SHIFT)
 #define extract_global_pstate(x) extract_pstate(x, GPSTATE_SHIFT)
 #define extract_max_pstate(x)  extract_pstate(x, MAX_PSTATE_SHIFT)
 
 /* Use following functions for conversions between pstate_id and index */
 
 /*
  * idx_to_pstate : Returns the pstate id corresponding to the
  *         frequency in the cpufreq frequency table
  *         powernv_freqs indexed by @i.
  *
  *         If @i is out of bound, this will return the pstate
  *         corresponding to the nominal frequency.
  */
 static inline u8 idx_to_pstate(unsigned int i)
 {
     if (unlikely(i >= powernv_pstate_info.nr_pstates)) {
         pr_warn_once("idx_to_pstate: index %u is out of bound\n", i);
         return powernv_freqs[powernv_pstate_info.nominal].driver_data;
     }
 
     return powernv_freqs[i].driver_data;
 }
 
 /*
  * pstate_to_idx : Returns the index in the cpufreq frequencytable
  *         powernv_freqs for the frequency whose corresponding
  *         pstate id is @pstate.
  *
  *         If no frequency corresponding to @pstate is found,
  *         this will return the index of the nominal
  *         frequency.
  */
 static unsigned int pstate_to_idx(u8 pstate)
 {
     unsigned int key = pstate % POWERNV_MAX_PSTATES;
     struct pstate_idx_revmap_data *revmap_data;
 
     hash_for_each_possible(pstate_revmap, revmap_data, hentry, key) {
         if (revmap_data->pstate_id == pstate)
             return revmap_data->cpufreq_table_idx;
     }
 
     pr_warn_once("pstate_to_idx: pstate 0x%x not found\n", pstate);
     return powernv_pstate_info.nominal;
 }
 
 static inline void reset_gpstates(struct cpufreq_policy *policy)
 {
     struct global_pstate_info *gpstates = policy->driver_data;
 
     gpstates->highest_lpstate_idx = 0;
     gpstates->elapsed_time = 0;
     gpstates->last_sampled_time = 0;
     gpstates->last_lpstate_idx = 0;
     gpstates->last_gpstate_idx = 0;
 }
 
 /*
  * Initialize the freq table based on data obtained
  * from the firmware passed via device-tree
  */
 static int init_powernv_pstates(void)
 {
     struct device_node *power_mgt;
     int i, nr_pstates = 0;
     const __be32 *pstate_ids, *pstate_freqs;
     u32 len_ids, len_freqs;
     u32 pstate_min, pstate_max, pstate_nominal;
     u32 pstate_turbo, pstate_ultra_turbo;
     int rc = -ENODEV;
 
     power_mgt = of_find_node_by_path("/ibm,opal/power-mgt");
     if (!power_mgt) {
         pr_warn("power-mgt node not found\n");
         return -ENODEV;
     }
 
     if (of_property_read_u32(power_mgt, "ibm,pstate-min", &pstate_min)) {
         pr_warn("ibm,pstate-min node not found\n");
         goto out;
     }
 
     if (of_property_read_u32(power_mgt, "ibm,pstate-max", &pstate_max)) {
         pr_warn("ibm,pstate-max node not found\n");
         goto out;
     }
 
     if (of_property_read_u32(power_mgt, "ibm,pstate-nominal",
                  &pstate_nominal)) {
         pr_warn("ibm,pstate-nominal not found\n");
         goto out;
     }
 
     if (of_property_read_u32(power_mgt, "ibm,pstate-ultra-turbo",
                  &pstate_ultra_turbo)) {
         powernv_pstate_info.wof_enabled = false;
         goto next;
     }
 
     if (of_property_read_u32(power_mgt, "ibm,pstate-turbo",
                  &pstate_turbo)) {
         powernv_pstate_info.wof_enabled = false;
         goto next;
     }
 
     if (pstate_turbo == pstate_ultra_turbo)
         powernv_pstate_info.wof_enabled = false;
     else
         powernv_pstate_info.wof_enabled = true;
 
 next:
     pr_info("cpufreq pstate min 0x%x nominal 0x%x max 0x%x\n", pstate_min,
         pstate_nominal, pstate_max);
     pr_info("Workload Optimized Frequency is %s in the platform\n",
         (powernv_pstate_info.wof_enabled) ? "enabled" : "disabled");
 
     pstate_ids = of_get_property(power_mgt, "ibm,pstate-ids", &len_ids);
     if (!pstate_ids) {
         pr_warn("ibm,pstate-ids not found\n");
         goto out;
     }
 
     pstate_freqs = of_get_property(power_mgt, "ibm,pstate-frequencies-mhz",
                       &len_freqs);
     if (!pstate_freqs) {
         pr_warn("ibm,pstate-frequencies-mhz not found\n");
         goto out;
     }
 
     if (len_ids != len_freqs) {
         pr_warn("Entries in ibm,pstate-ids and "
             "ibm,pstate-frequencies-mhz does not match\n");
     }
 
     nr_pstates = min(len_ids, len_freqs) / sizeof(u32);
     if (!nr_pstates) {
         pr_warn("No PStates found\n");
         goto out;
     }
 
     powernv_pstate_info.nr_pstates = nr_pstates;
     pr_debug("NR PStates %d\n", nr_pstates);
 
     for (i = 0; i < nr_pstates; i++) {
         u32 id = be32_to_cpu(pstate_ids[i]);
         u32 freq = be32_to_cpu(pstate_freqs[i]);
         struct pstate_idx_revmap_data *revmap_data;
         unsigned int key;
 
         pr_debug("PState id %d freq %d MHz\n", id, freq);
         powernv_freqs[i].frequency = freq * 1000; /* kHz */
         powernv_freqs[i].driver_data = id & 0xFF;
 
         revmap_data = kmalloc(sizeof(*revmap_data), GFP_KERNEL);
         if (!revmap_data) {
             rc = -ENOMEM;
             goto out;
         }
 
         revmap_data->pstate_id = id & 0xFF;
         revmap_data->cpufreq_table_idx = i;
         key = (revmap_data->pstate_id) % POWERNV_MAX_PSTATES;
         hash_add(pstate_revmap, &revmap_data->hentry, key);
 
         if (id == pstate_max)
             powernv_pstate_info.max = i;
         if (id == pstate_nominal)
             powernv_pstate_info.nominal = i;
         if (id == pstate_min)
             powernv_pstate_info.min = i;
 
         if (powernv_pstate_info.wof_enabled && id == pstate_turbo) {
             int j;
 
             for (j = i - 1; j >= (int)powernv_pstate_info.max; j--)
                 powernv_freqs[j].flags = CPUFREQ_BOOST_FREQ;
         }
     }
 
     /* End of list marker entry */
     powernv_freqs[i].frequency = CPUFREQ_TABLE_END;
 
     of_node_put(power_mgt);
     return 0;
 out:
     of_node_put(power_mgt);
     return rc;
 }
 
 /* Returns the CPU frequency corresponding to the pstate_id. */
 static unsigned int pstate_id_to_freq(u8 pstate_id)
 {
     int i;
 
     i = pstate_to_idx(pstate_id);
     if (i >= powernv_pstate_info.nr_pstates || i < 0) {
         pr_warn("PState id 0x%x outside of PState table, reporting nominal id 0x%x instead\n",
             pstate_id, idx_to_pstate(powernv_pstate_info.nominal));
         i = powernv_pstate_info.nominal;
     }
 
     return powernv_freqs[i].frequency;
 }
 
 /*
  * cpuinfo_nominal_freq_show - Show the nominal CPU frequency as indicated by
  * the firmware
  */
 static ssize_t cpuinfo_nominal_freq_show(struct cpufreq_policy *policy,
                     char *buf)
 {
     return sprintf(buf, "%u\n",
         powernv_freqs[powernv_pstate_info.nominal].frequency);
 }
 
 static struct freq_attr cpufreq_freq_attr_cpuinfo_nominal_freq =
     __ATTR_RO(cpuinfo_nominal_freq);
 
 #define SCALING_BOOST_FREQS_ATTR_INDEX      2
 
 static struct freq_attr *powernv_cpu_freq_attr[] = {
     &cpufreq_freq_attr_scaling_available_freqs,
     &cpufreq_freq_attr_cpuinfo_nominal_freq,
     &cpufreq_freq_attr_scaling_boost_freqs,
     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 */
 
 static inline unsigned long get_pmspr(unsigned long sprn)
 {
     switch (sprn) {
     case SPRN_PMCR:
         return mfspr(SPRN_PMCR);
 
     case SPRN_PMICR:
         return mfspr(SPRN_PMICR);
 
     case SPRN_PMSR:
         return mfspr(SPRN_PMSR);
     }
     BUG();
 }
 
 static inline void set_pmspr(unsigned long sprn, unsigned long val)
 {
     switch (sprn) {
     case SPRN_PMCR:
         mtspr(SPRN_PMCR, val);
         return;
 
     case SPRN_PMICR:
         mtspr(SPRN_PMICR, val);
         return;
     }
     BUG();
 }
 
 /*
  * Use objects of this type to query/update
  * pstates on a remote CPU via smp_call_function.
  */
 struct powernv_smp_call_data {
     unsigned int freq;
     u8 pstate_id;
     u8 gpstate_id;
 };
 
 /*
  * powernv_read_cpu_freq: Reads the current frequency on this CPU.
  *
  * Called via smp_call_function.
  *
  * Note: The caller of the smp_call_function should pass an argument of
  * the type 'struct powernv_smp_call_data *' along with this function.
  *
  * The current frequency on this CPU will be returned via
  * ((struct powernv_smp_call_data *)arg)->freq;
  */
 static void powernv_read_cpu_freq(void *arg)
 {
     unsigned long pmspr_val;
     struct powernv_smp_call_data *freq_data = arg;
 
     pmspr_val = get_pmspr(SPRN_PMSR);
     freq_data->pstate_id = extract_local_pstate(pmspr_val);
     freq_data->freq = pstate_id_to_freq(freq_data->pstate_id);
 
     pr_debug("cpu %d pmsr %016lX pstate_id 0x%x frequency %d kHz\n",
          raw_smp_processor_id(), pmspr_val, freq_data->pstate_id,
          freq_data->freq);
 }
 
 /*
  * powernv_cpufreq_get: Returns the CPU frequency as reported by the
  * firmware for CPU 'cpu'. This value is reported through the sysfs
  * file cpuinfo_cur_freq.
  */
 static unsigned int powernv_cpufreq_get(unsigned int cpu)
 {
     struct powernv_smp_call_data freq_data;
 
     smp_call_function_any(cpu_sibling_mask(cpu), powernv_read_cpu_freq,
             &freq_data, 1);
 
     return freq_data.freq;
 }
 
 /*
  * set_pstate: Sets the pstate on this CPU.
  *
  * This is called via an smp_call_function.
  *
  * The caller must ensure that freq_data is of the type
  * (struct powernv_smp_call_data *) and the pstate_id which needs to be set
  * on this CPU should be present in freq_data->pstate_id.
  */
 static void set_pstate(void *data)
 {
     unsigned long val;
     struct powernv_smp_call_data *freq_data = data;
     unsigned long pstate_ul = freq_data->pstate_id;
     unsigned long gpstate_ul = freq_data->gpstate_id;
 
     val = get_pmspr(SPRN_PMCR);
     val = val & 0x0000FFFFFFFFFFFFULL;
 
     pstate_ul = pstate_ul & 0xFF;
     gpstate_ul = gpstate_ul & 0xFF;
 
     /* Set both global(bits 56..63) and local(bits 48..55) PStates */
     val = val | (gpstate_ul << 56) | (pstate_ul << 48);
 
     pr_debug("Setting cpu %d pmcr to %016lX\n",
             raw_smp_processor_id(), val);
     set_pmspr(SPRN_PMCR, val);
 }
 
 /*
  * get_nominal_index: Returns the index corresponding to the nominal
  * pstate in the cpufreq table
  */
 static inline unsigned int get_nominal_index(void)
 {
     return powernv_pstate_info.nominal;
 }
 
 static void powernv_cpufreq_throttle_check(void *data)
 {
     struct chip *chip;
     unsigned int cpu = smp_processor_id();
     unsigned long pmsr;
     u8 pmsr_pmax;
     unsigned int pmsr_pmax_idx;
 
     pmsr = get_pmspr(SPRN_PMSR);
     chip = this_cpu_read(chip_info);
 
     /* Check for Pmax Capping */
     pmsr_pmax = extract_max_pstate(pmsr);
     pmsr_pmax_idx = pstate_to_idx(pmsr_pmax);
     if (pmsr_pmax_idx != powernv_pstate_info.max) {
         if (chip->throttled)
             goto next;
         chip->throttled = true;
         if (pmsr_pmax_idx > powernv_pstate_info.nominal) {
             pr_warn_once("CPU %d on Chip %u has Pmax(0x%x) reduced below that of nominal frequency(0x%x)\n",
                      cpu, chip->id, pmsr_pmax,
                      idx_to_pstate(powernv_pstate_info.nominal));
             chip->throttle_sub_turbo++;
         } else {
             chip->throttle_turbo++;
         }
         trace_powernv_throttle(chip->id,
                       throttle_reason[chip->throttle_reason],
                       pmsr_pmax);
     } else if (chip->throttled) {
         chip->throttled = false;
         trace_powernv_throttle(chip->id,
                       throttle_reason[chip->throttle_reason],
                       pmsr_pmax);
     }
 
     /* Check if Psafe_mode_active is set in PMSR. */
 next:
     if (pmsr & PMSR_PSAFE_ENABLE) {
         throttled = true;
         pr_info("Pstate set to safe frequency\n");
     }
 
     /* Check if SPR_EM_DISABLE is set in PMSR */
     if (pmsr & PMSR_SPR_EM_DISABLE) {
         throttled = true;
         pr_info("Frequency Control disabled from OS\n");
     }
 
     if (throttled) {
         pr_info("PMSR = %16lx\n", pmsr);
         pr_warn("CPU Frequency could be throttled\n");
     }
 }
 
 /**
  * calc_global_pstate - Calculate global pstate
  * @elapsed_time:       Elapsed time in milliseconds
  * @local_pstate_idx:       New local pstate
  * @highest_lpstate_idx:    pstate from which its ramping down
  *
  * Finds the appropriate global pstate based on the pstate from which its
  * ramping down and the time elapsed in ramping down. It follows a quadratic
  * equation which ensures that it reaches ramping down to pmin in 5sec.
  */
 static inline int calc_global_pstate(unsigned int elapsed_time,
                      int highest_lpstate_idx,
                      int local_pstate_idx)
 {
     int index_diff;
 
     /*
      * Using ramp_down_percent we get the percentage of rampdown
      * that we are expecting to be dropping. Difference between
      * highest_lpstate_idx and powernv_pstate_info.min will give a absolute
      * number of how many pstates we will drop eventually by the end of
      * 5 seconds, then just scale it get the number pstates to be dropped.
      */
     index_diff =  ((int)ramp_down_percent(elapsed_time) *
             (powernv_pstate_info.min - highest_lpstate_idx)) / 100;
 
     /* Ensure that global pstate is >= to local pstate */
     if (highest_lpstate_idx + index_diff >= local_pstate_idx)
         return local_pstate_idx;
     else
         return highest_lpstate_idx + index_diff;
 }
 
 static inline void  queue_gpstate_timer(struct global_pstate_info *gpstates)
 {
     unsigned int timer_interval;
 
     /*
      * Setting up timer to fire after GPSTATE_TIMER_INTERVAL ms, But
      * if it exceeds MAX_RAMP_DOWN_TIME ms for ramp down time.
      * Set timer such that it fires exactly at MAX_RAMP_DOWN_TIME
      * seconds of ramp down time.
      */
     if ((gpstates->elapsed_time + GPSTATE_TIMER_INTERVAL)
          > MAX_RAMP_DOWN_TIME)
         timer_interval = MAX_RAMP_DOWN_TIME - gpstates->elapsed_time;
     else
         timer_interval = GPSTATE_TIMER_INTERVAL;
 
     mod_timer(&gpstates->timer, jiffies + msecs_to_jiffies(timer_interval));
 }
 
 /**
  * gpstate_timer_handler
  *
  * @t: Timer context used to fetch global pstate info struct
  *
  * This handler brings down the global pstate closer to the local pstate
  * according quadratic equation. Queues a new timer if it is still not equal
  * to local pstate
  */
 static void gpstate_timer_handler(struct timer_list *t)
 {
     struct global_pstate_info *gpstates = from_timer(gpstates, t, timer);
     struct cpufreq_policy *policy = gpstates->policy;
     int gpstate_idx, lpstate_idx;
     unsigned long val;
     unsigned int time_diff = jiffies_to_msecs(jiffies)
                     - gpstates->last_sampled_time;
     struct powernv_smp_call_data freq_data;
 
     if (!spin_trylock(&gpstates->gpstate_lock))
         return;
     /*
      * If the timer has migrated to the different cpu then bring
      * it back to one of the policy->cpus
      */
     if (!cpumask_test_cpu(raw_smp_processor_id(), policy->cpus)) {
         gpstates->timer.expires = jiffies + msecs_to_jiffies(1);
         add_timer_on(&gpstates->timer, cpumask_first(policy->cpus));
         spin_unlock(&gpstates->gpstate_lock);
         return;
     }
 
     /*
      * If PMCR was last updated was using fast_swtich then
      * We may have wrong in gpstate->last_lpstate_idx
      * value. Hence, read from PMCR to get correct data.
      */
     val = get_pmspr(SPRN_PMCR);
     freq_data.gpstate_id = extract_global_pstate(val);
     freq_data.pstate_id = extract_local_pstate(val);
     if (freq_data.gpstate_id  == freq_data.pstate_id) {
         reset_gpstates(policy);
         spin_unlock(&gpstates->gpstate_lock);
         return;
     }
 
     gpstates->last_sampled_time += time_diff;
     gpstates->elapsed_time += time_diff;
 
     if (gpstates->elapsed_time > MAX_RAMP_DOWN_TIME) {
         gpstate_idx = pstate_to_idx(freq_data.pstate_id);
         lpstate_idx = gpstate_idx;
         reset_gpstates(policy);
         gpstates->highest_lpstate_idx = gpstate_idx;
     } else {
         lpstate_idx = pstate_to_idx(freq_data.pstate_id);
         gpstate_idx = calc_global_pstate(gpstates->elapsed_time,
                          gpstates->highest_lpstate_idx,
                          lpstate_idx);
     }
     freq_data.gpstate_id = idx_to_pstate(gpstate_idx);
     gpstates->last_gpstate_idx = gpstate_idx;
     gpstates->last_lpstate_idx = lpstate_idx;
     /*
      * If local pstate is equal to global pstate, rampdown is over
      * So timer is not required to be queued.
      */
     if (gpstate_idx != gpstates->last_lpstate_idx)
         queue_gpstate_timer(gpstates);
 
     set_pstate(&freq_data);
     spin_unlock(&gpstates->gpstate_lock);
 }
 
 /*
  * powernv_cpufreq_target_index: Sets the frequency corresponding to
  * the cpufreq table entry indexed by new_index on the cpus in the
  * mask policy->cpus
  */
 static int powernv_cpufreq_target_index(struct cpufreq_policy *policy,
                     unsigned int new_index)
 {
     struct powernv_smp_call_data freq_data;
     unsigned int cur_msec, gpstate_idx;
     struct global_pstate_info *gpstates = policy->driver_data;
 
     if (unlikely(rebooting) && new_index != get_nominal_index())
         return 0;
 
     if (!throttled) {
         /* we don't want to be preempted while
          * checking if the CPU frequency has been throttled
          */
         preempt_disable();
         powernv_cpufreq_throttle_check(NULL);
         preempt_enable();
     }
 
     cur_msec = jiffies_to_msecs(get_jiffies_64());
 
     freq_data.pstate_id = idx_to_pstate(new_index);
     if (!gpstates) {
         freq_data.gpstate_id = freq_data.pstate_id;
         goto no_gpstate;
     }
 
     spin_lock(&gpstates->gpstate_lock);
 
     if (!gpstates->last_sampled_time) {
         gpstate_idx = new_index;
         gpstates->highest_lpstate_idx = new_index;
         goto gpstates_done;
     }
 
     if (gpstates->last_gpstate_idx < new_index) {
         gpstates->elapsed_time += cur_msec -
                          gpstates->last_sampled_time;
 
         /*
          * If its has been ramping down for more than MAX_RAMP_DOWN_TIME
          * we should be resetting all global pstate related data. Set it
          * equal to local pstate to start fresh.
          */
         if (gpstates->elapsed_time > MAX_RAMP_DOWN_TIME) {
             reset_gpstates(policy);
             gpstates->highest_lpstate_idx = new_index;
             gpstate_idx = new_index;
         } else {
         /* Elaspsed_time is less than 5 seconds, continue to rampdown */
             gpstate_idx = calc_global_pstate(gpstates->elapsed_time,
                              gpstates->highest_lpstate_idx,
                              new_index);
         }
     } else {
         reset_gpstates(policy);
         gpstates->highest_lpstate_idx = new_index;
         gpstate_idx = new_index;
     }
 
     /*
      * If local pstate is equal to global pstate, rampdown is over
      * So timer is not required to be queued.
      */
     if (gpstate_idx != new_index)
         queue_gpstate_timer(gpstates);
     else
         del_timer_sync(&gpstates->timer);
 
 gpstates_done:
     freq_data.gpstate_id = idx_to_pstate(gpstate_idx);
     gpstates->last_sampled_time = cur_msec;
     gpstates->last_gpstate_idx = gpstate_idx;
     gpstates->last_lpstate_idx = new_index;
 
     spin_unlock(&gpstates->gpstate_lock);
 
 no_gpstate:
     /*
      * Use smp_call_function to send IPI and execute the
      * mtspr on target CPU.  We could do that without IPI
      * if current CPU is within policy->cpus (core)
      */
     smp_call_function_any(policy->cpus, set_pstate, &freq_data, 1);
     return 0;
 }
 
 static int powernv_cpufreq_cpu_init(struct cpufreq_policy *policy)
 {
     int base, i;
     struct kernfs_node *kn;
     struct global_pstate_info *gpstates;
 
     base = cpu_first_thread_sibling(policy->cpu);
 
     for (i = 0; i < threads_per_core; i++)
         cpumask_set_cpu(base + i, policy->cpus);
 
     kn = kernfs_find_and_get(policy->kobj.sd, throttle_attr_grp.name);
     if (!kn) {
         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;
         }
     } else {
         kernfs_put(kn);
     }
 
     policy->freq_table = powernv_freqs;
     policy->fast_switch_possible = true;
 
     if (pvr_version_is(PVR_POWER9))
         return 0;
 
     /* Initialise Gpstate ramp-down timer only on POWER8 */
     gpstates =  kzalloc(sizeof(*gpstates), GFP_KERNEL);
     if (!gpstates)
         return -ENOMEM;
 
     policy->driver_data = gpstates;
 
     /* initialize timer */
     gpstates->policy = policy;
     timer_setup(&gpstates->timer, gpstate_timer_handler,
             TIMER_PINNED | TIMER_DEFERRABLE);
     gpstates->timer.expires = jiffies +
                 msecs_to_jiffies(GPSTATE_TIMER_INTERVAL);
     spin_lock_init(&gpstates->gpstate_lock);
 
     return 0;
 }
 
 static int powernv_cpufreq_cpu_exit(struct cpufreq_policy *policy)
 {
     struct powernv_smp_call_data freq_data;
     struct global_pstate_info *gpstates = policy->driver_data;
 
     freq_data.pstate_id = idx_to_pstate(powernv_pstate_info.min);
     freq_data.gpstate_id = idx_to_pstate(powernv_pstate_info.min);
     smp_call_function_single(policy->cpu, set_pstate, &freq_data, 1);
     if (gpstates)
         del_timer_sync(&gpstates->timer);
 
     kfree(policy->driver_data);
 
     return 0;
 }
 
 static int powernv_cpufreq_reboot_notifier(struct notifier_block *nb,
                 unsigned long action, void *unused)
 {
     int cpu;
     struct cpufreq_policy *cpu_policy;
 
     rebooting = true;
     for_each_online_cpu(cpu) {
         cpu_policy = cpufreq_cpu_get(cpu);
         if (!cpu_policy)
             continue;
         powernv_cpufreq_target_index(cpu_policy, get_nominal_index());
         cpufreq_cpu_put(cpu_policy);
     }
 
     return NOTIFY_DONE;
 }
 
 static struct notifier_block powernv_cpufreq_reboot_nb = {
     .notifier_call = powernv_cpufreq_reboot_notifier,
 };
 
 static void powernv_cpufreq_work_fn(struct work_struct *work)
 {
     struct chip *chip = container_of(work, struct chip, throttle);
     struct cpufreq_policy *policy;
     unsigned int cpu;
     cpumask_t mask;
 
     cpus_read_lock();
     cpumask_and(&mask, &chip->mask, cpu_online_mask);
     smp_call_function_any(&mask,
                   powernv_cpufreq_throttle_check, NULL, 0);
 
     if (!chip->restore)
         goto out;
 
     chip->restore = false;
     for_each_cpu(cpu, &mask) {
         int index;
 
         policy = cpufreq_cpu_get(cpu);
         if (!policy)
             continue;
         index = cpufreq_table_find_index_c(policy, policy->cur, false);
         powernv_cpufreq_target_index(policy, index);
         cpumask_andnot(&mask, &mask, policy->cpus);
         cpufreq_cpu_put(policy);
     }
 out:
     cpus_read_unlock();
 }
 
 static int powernv_cpufreq_occ_msg(struct notifier_block *nb,
                    unsigned long msg_type, void *_msg)
 {
     struct opal_msg *msg = _msg;
     struct opal_occ_msg omsg;
     int i;
 
     if (msg_type != OPAL_MSG_OCC)
         return 0;
 
     omsg.type = be64_to_cpu(msg->params[0]);
 
     switch (omsg.type) {
     case OCC_RESET:
         occ_reset = true;
         pr_info("OCC (On Chip Controller - enforces hard thermal/power limits) Resetting\n");
         /*
          * powernv_cpufreq_throttle_check() is called in
          * target() callback which can detect the throttle state
          * for governors like ondemand.
          * But static governors will not call target() often thus
          * report throttling here.
          */
         if (!throttled) {
             throttled = true;
             pr_warn("CPU frequency is throttled for duration\n");
         }
 
         break;
     case OCC_LOAD:
         pr_info("OCC Loading, CPU frequency is throttled until OCC is started\n");
         break;
     case OCC_THROTTLE:
         omsg.chip = be64_to_cpu(msg->params[1]);
         omsg.throttle_status = be64_to_cpu(msg->params[2]);
 
         if (occ_reset) {
             occ_reset = false;
             throttled = false;
             pr_info("OCC Active, CPU frequency is no longer throttled\n");
 
             for (i = 0; i < nr_chips; i++) {
                 chips[i].restore = true;
                 schedule_work(&chips[i].throttle);
             }
 
             return 0;
         }
 
         for (i = 0; i < nr_chips; i++)
             if (chips[i].id == omsg.chip)
                 break;
 
         if (omsg.throttle_status >= 0 &&
             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;
 
         schedule_work(&chips[i].throttle);
     }
     return 0;
 }
 
 static struct notifier_block powernv_cpufreq_opal_nb = {
     .notifier_call  = powernv_cpufreq_occ_msg,
     .next       = NULL,
     .priority   = 0,
 };
 
 static unsigned int powernv_fast_switch(struct cpufreq_policy *policy,
                     unsigned int target_freq)
 {
     int index;
     struct powernv_smp_call_data freq_data;
 
     index = cpufreq_table_find_index_dl(policy, target_freq, false);
     freq_data.pstate_id = powernv_freqs[index].driver_data;
     freq_data.gpstate_id = powernv_freqs[index].driver_data;
     set_pstate(&freq_data);
 
     return powernv_freqs[index].frequency;
 }
 
 static struct cpufreq_driver powernv_cpufreq_driver = {
     .name       = "powernv-cpufreq",
     .flags      = CPUFREQ_CONST_LOOPS,
     .init       = powernv_cpufreq_cpu_init,
     .exit       = powernv_cpufreq_cpu_exit,
     .verify     = cpufreq_generic_frequency_table_verify,
     .target_index   = powernv_cpufreq_target_index,
     .fast_switch    = powernv_fast_switch,
     .get        = powernv_cpufreq_get,
     .attr       = powernv_cpu_freq_attr,
 };
 
 static int init_chip_info(void)
 {
     unsigned int *chip;
     unsigned int cpu, i;
     unsigned int prev_chip_id = UINT_MAX;
     cpumask_t *chip_cpu_mask;
     int ret = 0;
 
     chip = kcalloc(num_possible_cpus(), sizeof(*chip), GFP_KERNEL);
     if (!chip)
         return -ENOMEM;
 
     /* Allocate a chip cpu mask large enough to fit mask for all chips */
     chip_cpu_mask = kcalloc(MAX_NR_CHIPS, sizeof(cpumask_t), GFP_KERNEL);
     if (!chip_cpu_mask) {
         ret = -ENOMEM;
         goto free_and_return;
     }
 
     for_each_possible_cpu(cpu) {
         unsigned int id = cpu_to_chip_id(cpu);
 
         if (prev_chip_id != id) {
             prev_chip_id = id;
             chip[nr_chips++] = id;
         }
         cpumask_set_cpu(cpu, &chip_cpu_mask[nr_chips-1]);
     }
 
     chips = kcalloc(nr_chips, sizeof(struct chip), GFP_KERNEL);
     if (!chips) {
         ret = -ENOMEM;
         goto out_free_chip_cpu_mask;
     }
 
     for (i = 0; i < nr_chips; i++) {
         chips[i].id = chip[i];
         cpumask_copy(&chips[i].mask, &chip_cpu_mask[i]);
         INIT_WORK(&chips[i].throttle, powernv_cpufreq_work_fn);
         for_each_cpu(cpu, &chips[i].mask)
             per_cpu(chip_info, cpu) =  &chips[i];
     }
 
 out_free_chip_cpu_mask:
     kfree(chip_cpu_mask);
 free_and_return:
     kfree(chip);
     return ret;
 }
 
 static inline void clean_chip_info(void)
 {
     int i;
 
     /* flush any pending work items */
     if (chips)
         for (i = 0; i < nr_chips; i++)
             cancel_work_sync(&chips[i].throttle);
     kfree(chips);
 }
 
 static inline void unregister_all_notifiers(void)
 {
     opal_message_notifier_unregister(OPAL_MSG_OCC,
                      &powernv_cpufreq_opal_nb);
     unregister_reboot_notifier(&powernv_cpufreq_reboot_nb);
 }
 
 static int __init powernv_cpufreq_init(void)
 {
     int rc = 0;
 
     /* Don't probe on pseries (guest) platforms */
     if (!firmware_has_feature(FW_FEATURE_OPAL))
         return -ENODEV;
 
     /* Discover pstates from device tree and init */
     rc = init_powernv_pstates();
     if (rc)
         goto out;
 
     /* Populate chip info */
     rc = init_chip_info();
     if (rc)
         goto out;
 
     if (powernv_pstate_info.wof_enabled)
         powernv_cpufreq_driver.boost_enabled = true;
     else
         powernv_cpu_freq_attr[SCALING_BOOST_FREQS_ATTR_INDEX] = NULL;
 
     rc = cpufreq_register_driver(&powernv_cpufreq_driver);
     if (rc) {
         pr_info("Failed to register the cpufreq driver (%d)\n", rc);
         goto cleanup;
     }
 
     if (powernv_pstate_info.wof_enabled)
         cpufreq_enable_boost_support();
 
     register_reboot_notifier(&powernv_cpufreq_reboot_nb);
     opal_message_notifier_register(OPAL_MSG_OCC, &powernv_cpufreq_opal_nb);
 
     return 0;
 cleanup:
     clean_chip_info();
 out:
     pr_info("Platform driver disabled. System does not support PState control\n");
     return rc;
 }
 module_init(powernv_cpufreq_init);
 
 static void __exit powernv_cpufreq_exit(void)
 {
     cpufreq_unregister_driver(&powernv_cpufreq_driver);
     unregister_all_notifiers();
     clean_chip_info();
 }
 module_exit(powernv_cpufreq_exit);
 
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Vaidyanathan Srinivasan <svaidy at linux.vnet.ibm.com>");

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