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intel_idle: Allow ACPI _CST to be used for selected known processors 

Update the intel_idle driver to get the C-states information from ACPI
_CST in some cases in which the processor is known to the driver, as long as
that information is available and the new use_acpi flag is set in the
profile of the processor in question.

In the cases when there is a specific table of C-states for the given
processor in the driver, that table is used as the primary source of
information on the available C-states, but if ACPI _CST is present,
the C-states that are not listed by it will not be enabled by default
(they still can be enabled later by user space via sysfs, though).

The new CPUIDLE_FLAG_ALWAYS_ENABLE flag can be used for marking
C-states that should be enabled by default even if they are not
listed by ACPI _CST.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Rafael J. Wysocki 2019-12-13 09:56:21 +01:00
parent 75a8026741
commit bff8e60a86
1 changed files with 42 additions and 3 deletions
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45
drivers/idle/intel_idle.c
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@ -80,6 +80,7 @@ struct idle_cpu {
unsigned long auto_demotion_disable_flags;
bool byt_auto_demotion_disable_flag;
bool disable_promotion_to_c1e;
bool use_acpi;
};
static const struct idle_cpu *icpu;
@ -90,6 +91,11 @@ static void intel_idle_s2idle(struct cpuidle_device *dev,
struct cpuidle_driver *drv, int index);
static struct cpuidle_state *cpuidle_state_table;
/*
* Enable this state by default even if the ACPI _CST does not list it.
*/
#define CPUIDLE_FLAG_ALWAYS_ENABLE BIT(15)
/*
* Set this flag for states where the HW flushes the TLB for us
* and so we don't need cross-calls to keep it consistent.
@ -1230,9 +1236,33 @@ static void intel_idle_init_cstates_acpi(struct cpuidle_driver *drv)
state->enter_s2idle = intel_idle_s2idle;
}
}
static bool intel_idle_off_by_default(u32 mwait_hint)
{
int cstate, limit;
/*
* If there are no _CST C-states, do not disable any C-states by
* default.
*/
if (!acpi_state_table.count)
return false;
limit = min_t(int, CPUIDLE_STATE_MAX, acpi_state_table.count);
/*
* If limit > 0, intel_idle_cst_usable() has returned 'true', so all of
* the interesting states are ACPI_CSTATE_FFH.
*/
for (cstate = 1; cstate < limit; cstate++) {
if (acpi_state_table.states[cstate].address == mwait_hint)
return false;
}
return true;
}
#else /* !CONFIG_ACPI_PROCESSOR_CSTATE */
static inline bool intel_idle_acpi_cst_extract(void) { return false; }
static inline void intel_idle_init_cstates_acpi(struct cpuidle_driver *drv) { }
static inline bool intel_idle_off_by_default(u32 mwait_hint) { return false; }
#endif /* !CONFIG_ACPI_PROCESSOR_CSTATE */
/*
@ -1273,10 +1303,13 @@ static int __init intel_idle_probe(void)
pr_debug("MWAIT substates: 0x%x\n", mwait_substates);
icpu = (const struct idle_cpu *)id->driver_data;
if (icpu)
if (icpu) {
cpuidle_state_table = icpu->state_table;
else if (!intel_idle_acpi_cst_extract())
if (icpu->use_acpi)
intel_idle_acpi_cst_extract();
} else if (!intel_idle_acpi_cst_extract()) {
return -ENODEV;
}
pr_debug("v" INTEL_IDLE_VERSION " model 0x%X\n",
boot_cpu_data.x86_model);
@ -1484,7 +1517,13 @@ static void intel_idle_init_cstates_icpu(struct cpuidle_driver *drv)
continue;
/* Structure copy. */
drv->states[drv->state_count++] = cpuidle_state_table[cstate];
drv->states[drv->state_count] = cpuidle_state_table[cstate];
if (icpu->use_acpi && intel_idle_off_by_default(mwait_hint) &&
!(cpuidle_state_table[cstate].flags & CPUIDLE_FLAG_ALWAYS_ENABLE))
drv->states[drv->state_count].flags |= CPUIDLE_FLAG_OFF;
drv->state_count++;
}
if (icpu->byt_auto_demotion_disable_flag) {