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| author | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2019-12-13 11:55:14 +0300 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2019-12-16 14:06:18 +0300 |
| commit | bc94638886ab21f8247d3f7f39573d3feb7d8284 (patch) | |
| tree | e74c747c0b82ced46eae2b09e1a2405fe4fc7b56 /drivers/acpi/acpi_processor.c | |
| parent | d1eef1c619749b2a57e514a3fa67d9a516ffa919 (diff) | |
| download | linux-bc94638886ab21f8247d3f7f39573d3feb7d8284.tar.xz | |
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>
Diffstat (limited to 'drivers/acpi/acpi_processor.c')
| -rw-r--r-- | drivers/acpi/acpi_processor.c | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c index 2c4dda0787e8..8a53f3c5b70e 100644 --- a/drivers/acpi/acpi_processor.c +++ b/drivers/acpi/acpi_processor.c @@ -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 */ |