From: "Gautham R. Shenoy" <e...@linux.vnet.ibm.com> The current frequency of a cpu is reported through the sysfs file cpuinfo_cur_freq. This requires the driver to implement a "->get(unsigned int cpu)" method which will return the current operating frequency.
Implement a function named powernv_cpufreq_get() which reads the local pstate from the PMSR and returns the corresponding frequency. Set the powernv_cpufreq_driver.get hook to powernv_cpufreq_get(). Signed-off-by: Gautham R. Shenoy <e...@linux.vnet.ibm.com> --- drivers/cpufreq/powernv-cpufreq.c | 48 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+) diff --git a/drivers/cpufreq/powernv-cpufreq.c b/drivers/cpufreq/powernv-cpufreq.c index 183bbc4..6f3b6e1 100644 --- a/drivers/cpufreq/powernv-cpufreq.c +++ b/drivers/cpufreq/powernv-cpufreq.c @@ -223,6 +223,53 @@ static inline void set_pmspr(unsigned long sprn, unsigned long val) BUG(); } +/* + * Computes the current frequency on this cpu + * and stores the result in *ret_freq. + */ +static void powernv_read_cpu_freq(void *ret_freq) +{ + unsigned long pmspr_val; + s8 local_pstate_id; + int *cur_freq, freq, pstate_id; + + cur_freq = (int *)ret_freq; + pmspr_val = get_pmspr(SPRN_PMSR); + + /* The local pstate id corresponds bits 48..55 in the PMSR. + * Note: Watch out for the sign! */ + local_pstate_id = (pmspr_val >> 48) & 0xFF; + pstate_id = local_pstate_id; + + freq = pstate_id_to_freq(pstate_id); + pr_debug("cpu %d pmsr %lx pstate_id %d frequency %d \n", + smp_processor_id(), pmspr_val, pstate_id, freq); + *cur_freq = freq; +} + +/* + * Returns the cpu frequency as reported by the firmware for 'cpu'. + * This value is reported through the sysfs file cpuinfo_cur_freq. + */ +unsigned int powernv_cpufreq_get(unsigned int cpu) +{ + int ret_freq; + cpumask_var_t sibling_mask; + + if (unlikely(!zalloc_cpumask_var(&sibling_mask, GFP_KERNEL))) { + smp_call_function_single(cpu, powernv_read_cpu_freq, + &ret_freq, 1); + return ret_freq; + } + + powernv_cpu_to_core_mask(cpu, sibling_mask); + smp_call_function_any(sibling_mask, powernv_read_cpu_freq, + &ret_freq, 1); + + free_cpumask_var(sibling_mask); + return ret_freq; +} + static void set_pstate(void *pstate) { unsigned long val; @@ -309,6 +356,7 @@ static int powernv_cpufreq_target(struct cpufreq_policy *policy, static struct cpufreq_driver powernv_cpufreq_driver = { .verify = powernv_cpufreq_verify, .target = powernv_cpufreq_target, + .get = powernv_cpufreq_get, .init = powernv_cpufreq_cpu_init, .exit = powernv_cpufreq_cpu_exit, .name = "powernv-cpufreq", -- 1.8.3.1 _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev