[PATCH v10 1/7] ACPI / processor_idle: introduce ACPI_PROCESSOR_CSTATE

Sudeep Holla
2016-07-19T17:52:53Z

ACPI 6.0 adds a new method to specify the CPU idle states(C-states)
called Low Power Idle(LPI) states. Since new architectures like ARM64
use only LPIs, introduce ACPI_PROCESSOR_CSTATE to encapsulate all the
code supporting the old style C-states(_CST).

This patch will help to extend the processor_idle module to support
LPI.

Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
---
drivers/acpi/Kconfig | 4 +++
drivers/acpi/processor_idle.c | 80 ++++++++++++++++++++++++++++---------------
include/acpi/processor.h | 2 +-
3 files changed, 58 insertions(+), 28 deletions(-)

diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index b7e2e776397d..1358fb7d7a68 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -213,6 +213,10 @@ config ACPI_CPU_FREQ_PSS
bool
select THERMAL

+config ACPI_PROCESSOR_CSTATE
+ def_bool y
+ depends on IA64 || X86
+
config ACPI_PROCESSOR_IDLE
bool
select CPU_IDLE
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 444e3745c8b3..ca0de35d1c3a 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -59,6 +59,12 @@ module_param(latency_factor, uint, 0644);

static DEFINE_PER_CPU(struct cpuidle_device *, acpi_cpuidle_device);

+struct cpuidle_driver acpi_idle_driver = {
+ .name = "acpi_idle",
+ .owner = THIS_MODULE,
+};
+
+#ifdef CONFIG_ACPI_PROCESSOR_CSTATE
static
DEFINE_PER_CPU(struct acpi_processor_cx * [CPUIDLE_STATE_MAX], acpi_cstate);

@@ -804,11 +810,6 @@ static void acpi_idle_enter_freeze(struct cpuidle_device *dev,
acpi_idle_do_entry(cx);
}

-struct cpuidle_driver acpi_idle_driver = {
- .name = "acpi_idle",
- .owner = THIS_MODULE,
-};
-
/**
* acpi_processor_setup_cpuidle_cx - prepares and configures CPUIDLE
* device i.e. per-cpu data
@@ -925,6 +926,50 @@ static int acpi_processor_setup_cpuidle_states(struct acpi_processor *pr)
return 0;
}

+static inline void acpi_processor_cstate_first_run_checks(void)
+{
+ acpi_status status;
+ static int first_run;
+
+ if (first_run)
+ return;
+ dmi_check_system(processor_power_dmi_table);
+ max_cstate = acpi_processor_cstate_check(max_cstate);
+ if (max_cstate < ACPI_C_STATES_MAX)
+ pr_notice("ACPI: processor limited to max C-state %d\n",
+ max_cstate);
+ first_run++;
+
+ if (acpi_gbl_FADT.cst_control && !nocst) {
+ status = acpi_os_write_port(acpi_gbl_FADT.smi_command,
+ acpi_gbl_FADT.cst_control, 8);
+ if (ACPI_FAILURE(status))
+ ACPI_EXCEPTION((AE_INFO, status,
+ "Notifying BIOS of _CST ability failed"));
+ }
+}
+#else
+
+static inline int disabled_by_idle_boot_param(void) { return 0; }
+static inline void acpi_processor_cstate_first_run_checks(void) { }
+static int acpi_processor_get_power_info(struct acpi_processor *pr)
+{
+ return -ENODEV;
+}
+
+static int acpi_processor_setup_cpuidle_cx(struct acpi_processor *pr,
+ struct cpuidle_device *dev)
+{
+ return -EINVAL;
+}
+
+static int acpi_processor_setup_cpuidle_states(struct acpi_processor *pr)
+{
+ return -EINVAL;
+}
+
+#endif /* CONFIG_ACPI_PROCESSOR_CSTATE */
+
int acpi_processor_hotplug(struct acpi_processor *pr)
{
int ret = 0;
@@ -1015,35 +1060,16 @@ static int acpi_processor_registered;

int acpi_processor_power_init(struct acpi_processor *pr)
{
- acpi_status status;
int retval;
struct cpuidle_device *dev;
- static int first_run;

if (disabled_by_idle_boot_param())
return 0;

- if (!first_run) {
- dmi_check_system(processor_power_dmi_table);
- max_cstate = acpi_processor_cstate_check(max_cstate);
- if (max_cstate < ACPI_C_STATES_MAX)
- printk(KERN_NOTICE
- "ACPI: processor limited to max C-state %d\n",
- max_cstate);
- first_run++;
- }
+ acpi_processor_cstate_first_run_checks();

- if (acpi_gbl_FADT.cst_control && !nocst) {
- status =
- acpi_os_write_port(acpi_gbl_FADT.smi_command, acpi_gbl_FADT.cst_control, 8);
- if (ACPI_FAILURE(status)) {
- ACPI_EXCEPTION((AE_INFO, status,
- "Notifying BIOS of _CST ability failed"));
- }
- }
-
- acpi_processor_get_power_info(pr);
- pr->flags.power_setup_done = 1;
+ if (!acpi_processor_get_power_info(pr))
+ pr->flags.power_setup_done = 1;

/*
* Install the idle handler if processor power management is supported.
diff --git a/include/acpi/processor.h b/include/acpi/processor.h
index 6f1805dd5d3c..48779d678122 100644
--- a/include/acpi/processor.h
+++ b/include/acpi/processor.h
@@ -242,7 +242,7 @@ extern int acpi_processor_get_performance_info(struct acpi_processor *pr);
DECLARE_PER_CPU(struct acpi_processor *, processors);
extern struct acpi_processor_errata errata;

-#ifdef ARCH_HAS_POWER_INIT
+#if defined(ARCH_HAS_POWER_INIT) && defined(CONFIG_ACPI_PROCESSOR_CSTATE)
void acpi_processor_power_init_bm_check(struct acpi_processor_flags *flags,
unsigned int cpu);
int acpi_processor_ffh_cstate_probe(unsigned int cpu,
--
2.7.4