Re: [PATCH v2] cpufreq: powernv: Add support of frequency domain

From: Abhishek
Date: Mon Jan 22 2018 - 03:30:47 EST



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