[PATCH] cpufreq: powernv: Remove global pstate ramp-down timer in POWER9

[Shilpasri G Bhat]

POWER9 doesnot support global pstate requests for the chip. So remove
the timer logic which slowly ramps down the global pstate in P9
platforms.

Signed-off-by: Shilpasri G Bhat <shilpa.b...@linux.vnet.ibm.com>
---
 drivers/cpufreq/powernv-cpufreq.c | 23 ++++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/drivers/cpufreq/powernv-cpufreq.c 
b/drivers/cpufreq/powernv-cpufreq.c
index 0591874..71f8682 100644
--- a/drivers/cpufreq/powernv-cpufreq.c
+++ b/drivers/cpufreq/powernv-cpufreq.c
@@ -750,8 +750,13 @@ static int powernv_cpufreq_target_index(struct 
cpufreq_policy *policy,
 
        cur_msec = jiffies_to_msecs(get_jiffies_64());
 
-       spin_lock(&gpstates->gpstate_lock);
        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;
@@ -801,6 +806,7 @@ static int powernv_cpufreq_target_index(struct 
cpufreq_policy *policy,
 
        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
@@ -835,6 +841,13 @@ static int powernv_cpufreq_cpu_init(struct cpufreq_policy 
*policy)
                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;
@@ -849,15 +862,14 @@ static int powernv_cpufreq_cpu_init(struct cpufreq_policy 
*policy)
                                msecs_to_jiffies(GPSTATE_TIMER_INTERVAL);
        spin_lock_init(&gpstates->gpstate_lock);
 
-       policy->freq_table = powernv_freqs;
-       policy->fast_switch_possible = true;
        return 0;
 }
 
 static int powernv_cpufreq_cpu_exit(struct cpufreq_policy *policy)
 {
        /* timer is deleted in cpufreq_cpu_stop() */
-       kfree(policy->driver_data);
+       if (policy->driver_data)
+               kfree(policy->driver_data);
 
        return 0;
 }
@@ -990,7 +1002,8 @@ static void powernv_cpufreq_stop_cpu(struct cpufreq_policy 
*policy)
        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);
-       del_timer_sync(&gpstates->timer);
+       if (gpstates)
+               del_timer_sync(&gpstates->timer);
 }
 
 static unsigned int powernv_fast_switch(struct cpufreq_policy *policy,
-- 
1.8.3.1