// 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_obj(struct acpi_object_list);
        if (!obj_list)
                goto out;

        obj = kmalloc_obj(union acpi_object);
        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);
}