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Message-Id: <4f4552c9-c43d-1fbd-4ef5-6bed46a7a512@linux.vnet.ibm.com>
Date: Mon, 22 Jan 2018 14:00:32 +0530
From: Abhishek <huntbag@...ux.vnet.ibm.com>
To: Viresh Kumar <viresh.kumar@...aro.org>
Cc: rjw@...ysocki.net, benh@...nel.crashing.org, paulus@...ba.org,
mpe@...erman.id.au, linux-pm@...r.kernel.org,
linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] cpufreq: powernv: Add support of frequency domain
On 12/20/2017 12:20 PM, Viresh Kumar wrote:
> On 20-12-17, 12:12, Abhishek Goel wrote:
>> diff --git a/drivers/cpufreq/powernv-cpufreq.c b/drivers/cpufreq/powernv-cpufreq.c
>> index b6d7c4c..fd642bc 100644
>> --- a/drivers/cpufreq/powernv-cpufreq.c
>> +++ b/drivers/cpufreq/powernv-cpufreq.c
>> @@ -37,6 +37,7 @@
>> #include <asm/smp.h> /* Required for cpu_sibling_mask() in UP configs */
>> #include <asm/opal.h>
>> #include <linux/timer.h>
>> +#include <linux/hashtable.h>
>>
>> #define POWERNV_MAX_PSTATES 256
>> #define PMSR_PSAFE_ENABLE (1UL << 30)
>> @@ -130,6 +131,9 @@ static struct chip {
>> static int nr_chips;
>> static DEFINE_PER_CPU(struct chip *, chip_info);
>>
>> +static u32 freq_domain_indicator;
>> +static u32 flag;
> I wouldn't name it as flag, its unreadable. Maybe its better to name
> it based on the quirk you are trying to workaround with ?
>
>> +
>> /*
>> * Note:
>> * The set of pstates consists of contiguous integers.
>> @@ -194,6 +198,38 @@ static inline void reset_gpstates(struct cpufreq_policy *policy)
>> gpstates->last_gpstate_idx = 0;
>> }
>>
>> +#define SIZE NR_CPUS
>> +#define ORDER_FREQ_MAP ilog2(SIZE)
>> +
>> +static DEFINE_HASHTABLE(freq_domain_map, ORDER_FREQ_MAP);
>> +
>> +struct hashmap {
>> + cpumask_t mask;
>> + int chip_id;
>> + u32 pir_key;
>> + struct hlist_node hash_node;
>> +};
>> +
>> +static void insert(u32 key, int cpu)
>> +{
>> + struct hashmap *data;
>> +
>> + hash_for_each_possible(freq_domain_map, data, hash_node, key%SIZE) {
>> + if (data->chip_id == cpu_to_chip_id(cpu) &&
>> + data->pir_key == key) {
>> + cpumask_set_cpu(cpu, &data->mask);
>> + return;
>> + }
>> + }
>> +
>> + data = kzalloc(sizeof(*data), GFP_KERNEL);
>> + hash_add(freq_domain_map, &data->hash_node, key%SIZE);
>> + cpumask_set_cpu(cpu, &data->mask);
>> + data->chip_id = cpu_to_chip_id(cpu);
>> + data->pir_key = key;
>> +
>> +}
>> +
>> /*
>> * Initialize the freq table based on data obtained
>> * from the firmware passed via device-tree
>> @@ -206,7 +242,9 @@ static int init_powernv_pstates(void)
>> u32 len_ids, len_freqs;
>> u32 pstate_min, pstate_max, pstate_nominal;
>> u32 pstate_turbo, pstate_ultra_turbo;
>> + u32 key;
>>
>> + flag = 0;
> Isn't flag already 0 (global-uninitialized) ?
>
>> power_mgt = of_find_node_by_path("/ibm,opal/power-mgt");
>> if (!power_mgt) {
>> pr_warn("power-mgt node not found\n");
>> @@ -229,6 +267,17 @@ static int init_powernv_pstates(void)
>> return -ENODEV;
>> }
>>
>> + if (of_device_is_compatible(power_mgt, "freq-domain-v1") &&
>> + of_property_read_u32(power_mgt, "ibm,freq-domain-indicator",
>> + &freq_domain_indicator)) {
>> + pr_warn("ibm,freq-domain-indicator not found\n");
>> + freq_domain_indicator = 0;
> You shouldn't be required to set it to 0 here.
>
>> + }
>> +
>> + if (of_device_is_compatible(power_mgt, "P9-occ-quirk")) {
>> + flag = 1;
>> + }
> Remove {} and a better name like p9_occ_quirk would be good for flag.
> Also making it a bool may be better ?
>
>> +
>> if (of_property_read_u32(power_mgt, "ibm,pstate-ultra-turbo",
>> &pstate_ultra_turbo)) {
>> powernv_pstate_info.wof_enabled = false;
>> @@ -249,6 +298,7 @@ static int init_powernv_pstates(void)
>> next:
>> pr_info("cpufreq pstate min %d nominal %d max %d\n", pstate_min,
>> pstate_nominal, pstate_max);
>> + pr_info("frequency domain indicator %d", freq_domain_indicator);
>> pr_info("Workload Optimized Frequency is %s in the platform\n",
>> (powernv_pstate_info.wof_enabled) ? "enabled" : "disabled");
>>
>> @@ -276,6 +326,15 @@ static int init_powernv_pstates(void)
>> return -ENODEV;
>> }
>>
>> + if (freq_domain_indicator) {
>> + hash_init(freq_domain_map);
>> + for_each_possible_cpu(i) {
>> + key = ((u32) get_hard_smp_processor_id(i) &
>> + freq_domain_indicator);
> Maybe break it like:
>
> key = (u32) get_hard_smp_processor_id(i);
> key &= freq_domain_indicator;
>
> to make it easily readable ?
>
>> + insert(key, i);
>> + }
>> + }
>> +
>> powernv_pstate_info.nr_pstates = nr_pstates;
>> pr_debug("NR PStates %d\n", nr_pstates);
>> for (i = 0; i < nr_pstates; i++) {
>> @@ -693,6 +752,7 @@ static int powernv_cpufreq_target_index(struct cpufreq_policy *policy,
>> {
>> 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())
>> @@ -760,25 +820,55 @@ static int powernv_cpufreq_target_index(struct cpufreq_policy *policy,
>>
>> spin_unlock(&gpstates->gpstate_lock);
>>
>> - /*
>> - * 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);
>> + if (flag) {
> Maybe add a comment over this on why you need to do things differently
> here, as it isn't obvious.
>
>> + cpumask_t temp;
>> + u32 cpu;
>> +
>> + /*
>> + * Use smp_call_function to send IPI and execute the mtspr
>> + * on CPU. This needs to be done on every core of the policy.
>> + */
>> + cpumask_copy(&temp, policy->cpus);
>> + while (!cpumask_empty(&temp)) {
>> + cpu = cpumask_first(&temp);
>> + smp_call_function_any(cpu_sibling_mask(cpu),
>> + set_pstate, &freq_data, 1);
>> + cpumask_andnot(&temp, &temp, cpu_sibling_mask(cpu));
>> + }
>> + } else {
>> + 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, ret;
>> + int ret;
>> struct kernfs_node *kn;
>> struct global_pstate_info *gpstates;
>>
>> - base = cpu_first_thread_sibling(policy->cpu);
>> + if (!freq_domain_indicator) {
>> + int base, i;
>>
>> - for (i = 0; i < threads_per_core; i++)
>> - cpumask_set_cpu(base + i, policy->cpus);
>> + base = cpu_first_thread_sibling(policy->cpu);
>> + for (i = 0; i < threads_per_core; i++)
>> + cpumask_set_cpu(base + i, policy->cpus);
>> + } else {
>> + u32 key;
>> + struct hashmap *data;
>> +
>> + key = ((u32) get_hard_smp_processor_id(policy->cpu) &
>> + freq_domain_indicator);
>> + hash_for_each_possible(freq_domain_map, data, hash_node,
>> + key%SIZE) {
>> + if (data->chip_id == cpu_to_chip_id(policy->cpu) &&
>> + data->pir_key == key) {
>> + cpumask_copy(policy->cpus, &data->mask);
>> + break;
>> + }
>> + }
>> + }
>>
>> kn = kernfs_find_and_get(policy->kobj.sd, throttle_attr_grp.name);
>> if (!kn) {
>> --
>> 2.9.3
Have posted the next version with the changes made as suggested. Also
the skiboot patch required for the device tree changes made is posted
here : http://patchwork.ozlabs.org/patch/862256/
-Abhishek
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