1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Copyright (C) 2005 Intel Corporation
  4 * Copyright (C) 2009 Hewlett-Packard Development Company, L.P.
  5 *
  6 *      Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
  7 *      - Added _PDC for platforms with Intel CPUs
  8 */
  9
 10#define pr_fmt(fmt) "ACPI: " fmt
 11
 12#include <linux/slab.h>
 13#include <linux/acpi.h>
 14#include <acpi/processor.h>
 15
 16#include "internal.h"
 17
 18static void acpi_set_pdc_bits(u32 *buf)
 19{
 20	buf[0] = ACPI_PDC_REVISION_ID;
 21	buf[1] = 1;
 22	buf[2] = 0;
 23
 24	/* Twiddle arch-specific bits needed for _PDC */
 25	arch_acpi_set_proc_cap_bits(&buf[2]);
 26}
 27
 28static struct acpi_object_list *acpi_processor_alloc_pdc(void)
 29{
 30	struct acpi_object_list *obj_list;
 31	union acpi_object *obj;
 32	u32 *buf;
 33
 34	/* allocate and initialize pdc. It will be used later. */
 35	obj_list = kmalloc(sizeof(struct acpi_object_list), GFP_KERNEL);
 36	if (!obj_list)
 37		goto out;
 38
 39	obj = kmalloc(sizeof(union acpi_object), GFP_KERNEL);
 40	if (!obj) {
 41		kfree(obj_list);
 42		goto out;
 43	}
 44
 45	buf = kmalloc(12, GFP_KERNEL);
 46	if (!buf) {
 47		kfree(obj);
 48		kfree(obj_list);
 49		goto out;
 50	}
 51
 52	acpi_set_pdc_bits(buf);
 53
 54	obj->type = ACPI_TYPE_BUFFER;
 55	obj->buffer.length = 12;
 56	obj->buffer.pointer = (u8 *) buf;
 57	obj_list->count = 1;
 58	obj_list->pointer = obj;
 59
 60	return obj_list;
 61out:
 62	pr_err("Memory allocation error\n");
 63	return NULL;
 64}
 65
 66/*
 67 * _PDC is required for a BIOS-OS handshake for most of the newer
 68 * ACPI processor features.
 69 */
 70static acpi_status
 71acpi_processor_eval_pdc(acpi_handle handle, struct acpi_object_list *pdc_in)
 72{
 73	acpi_status status = AE_OK;
 74
 75	status = acpi_evaluate_object(handle, "_PDC", pdc_in, NULL);
 76
 77	if (ACPI_FAILURE(status))
 78		acpi_handle_debug(handle,
 79		    "Could not evaluate _PDC, using legacy perf control\n");
 80
 81	return status;
 82}
 83
 84void acpi_processor_set_pdc(acpi_handle handle)
 85{
 86	struct acpi_object_list *obj_list;
 87
 88	if (arch_has_acpi_pdc() == false)
 89		return;
 90
 91	obj_list = acpi_processor_alloc_pdc();
 92	if (!obj_list)
 93		return;
 94
 95	acpi_processor_eval_pdc(handle, obj_list);
 96
 97	kfree(obj_list->pointer->buffer.pointer);
 98	kfree(obj_list->pointer);
 99	kfree(obj_list);
100}
101
102static acpi_status __init
103early_init_pdc(acpi_handle handle, u32 lvl, void *context, void **rv)
104{
105	if (processor_physically_present(handle) == false)
106		return AE_OK;
107
108	acpi_processor_set_pdc(handle);
109	return AE_OK;
110}
111
112void __init acpi_early_processor_set_pdc(void)
113{
114	acpi_proc_quirk_mwait_check();
115
116	acpi_walk_namespace(ACPI_TYPE_PROCESSOR, ACPI_ROOT_OBJECT,
117			    ACPI_UINT32_MAX,
118			    early_init_pdc, NULL, NULL, NULL);
119	acpi_get_devices(ACPI_PROCESSOR_DEVICE_HID, early_init_pdc, NULL, NULL);
120}