diff options
| author | Akshay Adiga <akshay.adiga@linux.vnet.ibm.com> | 2016-11-08 19:03:28 +0530 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2016-11-11 01:41:02 +0100 |
| commit | 20b15b7663549b34abcb4a18f16fedb239406c41 (patch) | |
| tree | 1b1b4e306b28e582110b7481e53cd06feaa5103e /drivers/cpufreq/powernv-cpufreq.c | |
| parent | 60c9efb8f783194200bdb510df8d9d4fb398016e (diff) | |
cpufreq: powernv: Use PMCR to verify global and local pstate
As fast_switch() may get called with interrupt disable mode, we cannot
hold a mutex to update the global_pstate_info. So currently, fast_switch()
does not update the global_pstate_info and it will end up with stale data
whenever pstate is updated through fast_switch().
As the gpstate_timer can fire after fast_switch() has updated the pstates,
the timer handler cannot rely on the cached values of local and global
pstate and needs to read it from the PMCR.
Only gpstate_timer_handler() is affected by the stale cached pstate data
beacause either fast_switch() or target_index() routines will be called
for a given govenor, but gpstate_timer can fire after the governor has
changed to schedutil.
Signed-off-by: Akshay Adiga <akshay.adiga@linux.vnet.ibm.com>
Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/cpufreq/powernv-cpufreq.c')
| -rw-r--r-- | drivers/cpufreq/powernv-cpufreq.c | 36 |
1 files changed, 26 insertions, 10 deletions
diff --git a/drivers/cpufreq/powernv-cpufreq.c b/drivers/cpufreq/powernv-cpufreq.c index 4a4380d728ad..c82304b7a4c0 100644 --- a/drivers/cpufreq/powernv-cpufreq.c +++ b/drivers/cpufreq/powernv-cpufreq.c @@ -42,6 +42,10 @@ #define PMSR_PSAFE_ENABLE (1UL << 30) #define PMSR_SPR_EM_DISABLE (1UL << 31) #define PMSR_MAX(x) ((x >> 32) & 0xFF) +#define LPSTATE_SHIFT 48 +#define GPSTATE_SHIFT 56 +#define GET_LPSTATE(x) (((x) >> LPSTATE_SHIFT) & 0xFF) +#define GET_GPSTATE(x) (((x) >> GPSTATE_SHIFT) & 0xFF) #define MAX_RAMP_DOWN_TIME 5120 /* @@ -592,7 +596,8 @@ void gpstate_timer_handler(unsigned long data) { struct cpufreq_policy *policy = (struct cpufreq_policy *)data; struct global_pstate_info *gpstates = policy->driver_data; - int gpstate_idx; + 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; @@ -600,21 +605,36 @@ void gpstate_timer_handler(unsigned long data) if (!spin_trylock(&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 = (s8)GET_GPSTATE(val); + freq_data.pstate_id = (s8)GET_LPSTATE(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; - freq_data.pstate_id = idx_to_pstate(gpstates->last_lpstate_idx); - if ((gpstates->last_gpstate_idx == gpstates->last_lpstate_idx) || - (gpstates->elapsed_time > MAX_RAMP_DOWN_TIME)) { + if (gpstates->elapsed_time > MAX_RAMP_DOWN_TIME) { gpstate_idx = pstate_to_idx(freq_data.pstate_id); 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, - gpstates->last_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. @@ -622,10 +642,6 @@ void gpstate_timer_handler(unsigned long data) if (gpstate_idx != gpstates->last_lpstate_idx) queue_gpstate_timer(gpstates); - freq_data.gpstate_id = idx_to_pstate(gpstate_idx); - gpstates->last_gpstate_idx = pstate_to_idx(freq_data.gpstate_id); - gpstates->last_lpstate_idx = pstate_to_idx(freq_data.pstate_id); - spin_unlock(&gpstates->gpstate_lock); /* Timer may get migrated to a different cpu on cpu hot unplug */ |