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ACPI: processor: Export function to claim _CST control 

The intel_idle driver will be modified to use ACPI _CST subsequently
and it will need to notify the platform firmware of that if
acpi_gbl_FADT.cst_control is set, so add a routine for this purpose,
acpi_processor_claim_cst_control(), to acpi_processor.c (so that it
is always present which is required by intel_idle) and export it
to allow the ACPI processor driver (which is modular) to call it.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Rafael J. Wysocki 2019-12-13 09:55:14 +01:00
parent d1eef1c619
commit bc94638886
3 changed files with 35 additions and 8 deletions
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25
drivers/acpi/acpi_processor.c
View File

@ -705,3 +705,28 @@ void __init acpi_processor_init(void)
acpi_scan_add_handler_with_hotplug(&processor_handler, "processor");
acpi_scan_add_handler(&processor_container_handler);
}
#ifdef CONFIG_ACPI_PROCESSOR_CSTATE
/**
* acpi_processor_claim_cst_control - Request _CST control from the platform.
*/
bool acpi_processor_claim_cst_control(void)
{
static bool cst_control_claimed;
acpi_status status;
if (!acpi_gbl_FADT.cst_control || cst_control_claimed)
return true;
status = acpi_os_write_port(acpi_gbl_FADT.smi_command,
acpi_gbl_FADT.cst_control, 8);
if (ACPI_FAILURE(status)) {
pr_warn("ACPI: Failed to claim processor _CST control\n");
return false;
}
cst_control_claimed = true;
return true;
}
EXPORT_SYMBOL_GPL(acpi_processor_claim_cst_control);
#endif /* CONFIG_ACPI_PROCESSOR_CSTATE */

12
drivers/acpi/processor_idle.c
View File

@ -909,7 +909,6 @@ static int acpi_processor_setup_cstates(struct acpi_processor *pr)
static inline void acpi_processor_cstate_first_run_checks(void)
{
acpi_status status;
static int first_run;
if (first_run)
@ -921,13 +920,10 @@ static inline void acpi_processor_cstate_first_run_checks(void)
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"));
}
if (nocst)
return;
acpi_processor_claim_cst_control();
}
#else

6
include/linux/acpi.h
View File

@ -279,6 +279,12 @@ static inline bool invalid_phys_cpuid(phys_cpuid_t phys_id)
/* Validate the processor object's proc_id */
bool acpi_duplicate_processor_id(int proc_id);
/* Processor _CTS control */
#ifdef CONFIG_ACPI_PROCESSOR_CSTATE
bool acpi_processor_claim_cst_control(void);
#else
static inline bool acpi_processor_claim_cst_control(void) { return false; }
#endif
#ifdef CONFIG_ACPI_HOTPLUG_CPU
/* Arch dependent functions for cpu hotplug support */