intel_pstate: Add support for HWP
Add support of Hardware Managed Performance States (HWP) described in Volume 3
section 14.4 of the SDM.
With HWP enbaled intel_pstate will no longer be responsible for selecting P
states for the processor. intel_pstate will continue to register to
the cpufreq core as the scaling driver for CPUs implementing
HWP. In HWP mode intel_pstate provides three functions reporting
frequency to the cpufreq core, support for the set_policy() interface
from the core and maintaining the intel_pstate sysfs interface in
/sys/devices/system/cpu/intel_pstate. User preferences expressed via
the set_policy() interface or the sysfs interface are forwared to the
CPU via the HWP MSR interface.
Signed-off-by: Dirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index 27bb6d3..ba35db0 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -137,6 +137,7 @@
static struct pstate_adjust_policy pid_params;
static struct pstate_funcs pstate_funcs;
+static int hwp_active;
struct perf_limits {
int no_turbo;
@@ -244,6 +245,34 @@
cpu->pstate.max_pstate == cpu->pstate.turbo_pstate);
}
+#define PCT_TO_HWP(x) (x * 255 / 100)
+static void intel_pstate_hwp_set(void)
+{
+ int min, max, cpu;
+ u64 value, freq;
+
+ get_online_cpus();
+
+ for_each_online_cpu(cpu) {
+ rdmsrl_on_cpu(cpu, MSR_HWP_REQUEST, &value);
+ min = PCT_TO_HWP(limits.min_perf_pct);
+ value &= ~HWP_MIN_PERF(~0L);
+ value |= HWP_MIN_PERF(min);
+
+ max = PCT_TO_HWP(limits.max_perf_pct);
+ if (limits.no_turbo) {
+ rdmsrl( MSR_HWP_CAPABILITIES, freq);
+ max = HWP_GUARANTEED_PERF(freq);
+ }
+
+ value &= ~HWP_MAX_PERF(~0L);
+ value |= HWP_MAX_PERF(max);
+ wrmsrl_on_cpu(cpu, MSR_HWP_REQUEST, value);
+ }
+
+ put_online_cpus();
+}
+
/************************** debugfs begin ************************/
static int pid_param_set(void *data, u64 val)
{
@@ -279,6 +308,8 @@
struct dentry *debugfs_parent;
int i = 0;
+ if (hwp_active)
+ return;
debugfs_parent = debugfs_create_dir("pstate_snb", NULL);
if (IS_ERR_OR_NULL(debugfs_parent))
return;
@@ -329,8 +360,12 @@
pr_warn("Turbo disabled by BIOS or unavailable on processor\n");
return -EPERM;
}
+
limits.no_turbo = clamp_t(int, input, 0, 1);
+ if (hwp_active)
+ intel_pstate_hwp_set();
+
return count;
}
@@ -348,6 +383,8 @@
limits.max_perf_pct = min(limits.max_policy_pct, limits.max_sysfs_pct);
limits.max_perf = div_fp(int_tofp(limits.max_perf_pct), int_tofp(100));
+ if (hwp_active)
+ intel_pstate_hwp_set();
return count;
}
@@ -363,6 +400,8 @@
limits.min_perf_pct = clamp_t(int, input, 0 , 100);
limits.min_perf = div_fp(int_tofp(limits.min_perf_pct), int_tofp(100));
+ if (hwp_active)
+ intel_pstate_hwp_set();
return count;
}
@@ -395,8 +434,16 @@
rc = sysfs_create_group(intel_pstate_kobject, &intel_pstate_attr_group);
BUG_ON(rc);
}
-
/************************** sysfs end ************************/
+
+static void intel_pstate_hwp_enable(void)
+{
+ hwp_active++;
+ pr_info("intel_pstate HWP enabled\n");
+
+ wrmsrl( MSR_PM_ENABLE, 0x1);
+}
+
static int byt_get_min_pstate(void)
{
u64 value;
@@ -648,6 +695,14 @@
cpu->prev_mperf = mperf;
}
+static inline void intel_hwp_set_sample_time(struct cpudata *cpu)
+{
+ int delay;
+
+ delay = msecs_to_jiffies(50);
+ mod_timer_pinned(&cpu->timer, jiffies + delay);
+}
+
static inline void intel_pstate_set_sample_time(struct cpudata *cpu)
{
int delay;
@@ -694,6 +749,14 @@
intel_pstate_set_pstate(cpu, cpu->pstate.current_pstate - ctl);
}
+static void intel_hwp_timer_func(unsigned long __data)
+{
+ struct cpudata *cpu = (struct cpudata *) __data;
+
+ intel_pstate_sample(cpu);
+ intel_hwp_set_sample_time(cpu);
+}
+
static void intel_pstate_timer_func(unsigned long __data)
{
struct cpudata *cpu = (struct cpudata *) __data;
@@ -737,6 +800,11 @@
};
MODULE_DEVICE_TABLE(x86cpu, intel_pstate_cpu_ids);
+static const struct x86_cpu_id intel_pstate_cpu_oob_ids[] = {
+ ICPU(0x56, core_params),
+ {}
+};
+
static int intel_pstate_init_cpu(unsigned int cpunum)
{
struct cpudata *cpu;
@@ -753,9 +821,14 @@
intel_pstate_get_cpu_pstates(cpu);
init_timer_deferrable(&cpu->timer);
- cpu->timer.function = intel_pstate_timer_func;
cpu->timer.data = (unsigned long)cpu;
cpu->timer.expires = jiffies + HZ/100;
+
+ if (!hwp_active)
+ cpu->timer.function = intel_pstate_timer_func;
+ else
+ cpu->timer.function = intel_hwp_timer_func;
+
intel_pstate_busy_pid_reset(cpu);
intel_pstate_sample(cpu);
@@ -792,6 +865,7 @@
limits.no_turbo = 0;
return 0;
}
+
limits.min_perf_pct = (policy->min * 100) / policy->cpuinfo.max_freq;
limits.min_perf_pct = clamp_t(int, limits.min_perf_pct, 0 , 100);
limits.min_perf = div_fp(int_tofp(limits.min_perf_pct), int_tofp(100));
@@ -801,6 +875,9 @@
limits.max_perf_pct = min(limits.max_policy_pct, limits.max_sysfs_pct);
limits.max_perf = div_fp(int_tofp(limits.max_perf_pct), int_tofp(100));
+ if (hwp_active)
+ intel_pstate_hwp_set();
+
return 0;
}
@@ -823,6 +900,9 @@
pr_info("intel_pstate CPU %d exiting\n", cpu_num);
del_timer_sync(&all_cpu_data[cpu_num]->timer);
+ if (hwp_active)
+ return;
+
intel_pstate_set_pstate(cpu, cpu->pstate.min_pstate);
}
@@ -866,6 +946,7 @@
};
static int __initdata no_load;
+static int __initdata no_hwp;
static int intel_pstate_msrs_not_valid(void)
{
@@ -959,6 +1040,15 @@
{
struct acpi_table_header hdr;
struct hw_vendor_info *v_info;
+ const struct x86_cpu_id *id;
+ u64 misc_pwr;
+
+ id = x86_match_cpu(intel_pstate_cpu_oob_ids);
+ if (id) {
+ rdmsrl(MSR_MISC_PWR_MGMT, misc_pwr);
+ if ( misc_pwr & (1 << 8))
+ return true;
+ }
if (acpi_disabled ||
ACPI_FAILURE(acpi_get_table_header(ACPI_SIG_FADT, 0, &hdr)))
@@ -982,6 +1072,7 @@
int cpu, rc = 0;
const struct x86_cpu_id *id;
struct cpu_defaults *cpu_info;
+ struct cpuinfo_x86 *c = &boot_cpu_data;
if (no_load)
return -ENODEV;
@@ -1011,6 +1102,9 @@
if (!all_cpu_data)
return -ENOMEM;
+ if (cpu_has(c,X86_FEATURE_HWP) && !no_hwp)
+ intel_pstate_hwp_enable();
+
rc = cpufreq_register_driver(&intel_pstate_driver);
if (rc)
goto out;
@@ -1041,6 +1135,8 @@
if (!strcmp(str, "disable"))
no_load = 1;
+ if (!strcmp(str, "no_hwp"))
+ no_hwp = 1;
return 0;
}
early_param("intel_pstate", intel_pstate_setup);