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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2005 Intel Corporation
* Copyright (C) 2009 Hewlett-Packard Development Company, L.P.
*
* Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
* - Added _PDC for platforms with Intel CPUs
*/
#define pr_fmt(fmt) "ACPI: " fmt
#include <linux/slab.h>
#include <linux/acpi.h>
#include <acpi/processor.h>
#include "internal.h"
static void acpi_set_pdc_bits(u32 *buf)
{
buf[0] = ACPI_PDC_REVISION_ID;
buf[1] = 1;
buf[2] = 0;
/* Twiddle arch-specific bits needed for _PDC */
arch_acpi_set_proc_cap_bits(&buf[2]);
}
static struct acpi_object_list *acpi_processor_alloc_pdc(void)
{
struct acpi_object_list *obj_list;
union acpi_object *obj;
u32 *buf;
/* allocate and initialize pdc. It will be used later. */
obj_list = kmalloc(sizeof(struct acpi_object_list), GFP_KERNEL);
if (!obj_list)
goto out;
obj = kmalloc(sizeof(union acpi_object), GFP_KERNEL);
if (!obj) {
kfree(obj_list);
goto out;
}
buf = kmalloc(12, GFP_KERNEL);
if (!buf) {
kfree(obj);
kfree(obj_list);
goto out;
}
acpi_set_pdc_bits(buf);
obj->type = ACPI_TYPE_BUFFER;
obj->buffer.length = 12;
obj->buffer.pointer = (u8 *) buf;
obj_list->count = 1;
obj_list->pointer = obj;
return obj_list;
out:
pr_err("Memory allocation error\n");
return NULL;
}
/*
* _PDC is required for a BIOS-OS handshake for most of the newer
* ACPI processor features.
*/
static acpi_status
acpi_processor_eval_pdc(acpi_handle handle, struct acpi_object_list *pdc_in)
{
acpi_status status = AE_OK;
status = acpi_evaluate_object(handle, "_PDC", pdc_in, NULL);
if (ACPI_FAILURE(status))
acpi_handle_debug(handle,
"Could not evaluate _PDC, using legacy perf control\n");
return status;
}
void acpi_processor_set_pdc(acpi_handle handle)
{
struct acpi_object_list *obj_list;
if (arch_has_acpi_pdc() == false)
return;
obj_list = acpi_processor_alloc_pdc();
if (!obj_list)
return;
acpi_processor_eval_pdc(handle, obj_list);
kfree(obj_list->pointer->buffer.pointer);
kfree(obj_list->pointer);
kfree(obj_list);
}
static acpi_status __init
early_init_pdc(acpi_handle handle, u32 lvl, void *context, void **rv)
{
if (processor_physically_present(handle) == false)
return AE_OK;
acpi_processor_set_pdc(handle);
return AE_OK;
}
void __init acpi_early_processor_set_pdc(void)
{
acpi_proc_quirk_mwait_check();
acpi_walk_namespace(ACPI_TYPE_PROCESSOR, ACPI_ROOT_OBJECT,
ACPI_UINT32_MAX,
early_init_pdc, NULL, NULL, NULL);
acpi_get_devices(ACPI_PROCESSOR_DEVICE_HID, early_init_pdc, NULL, NULL);
}
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