Commit bc946388 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

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: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent d1eef1c6

drivers/acpi/acpi_processor.c

+25 −0
Original line number Diff line number Diff line
@@ -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 */

drivers/acpi/processor_idle.c

+4 −8
Original line number Diff line number Diff line
@@ -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

include/linux/acpi.h

+6 −0
Original line number Diff line number Diff line
@@ -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 */

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