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(cap: &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(objp: obj_list);
42 goto out;
43 }
44
45 buf = kmalloc(12, GFP_KERNEL);
46 if (!buf) {
47 kfree(objp: obj);
48 kfree(objp: 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(object: handle, pathname: "_PDC", parameter_objects: 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, pdc_in: obj_list);
96
97 kfree(objp: obj_list->pointer->buffer.pointer);
98 kfree(objp: obj_list->pointer);
99 kfree(objp: 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 descending_callback: early_init_pdc, NULL, NULL, NULL);
119 acpi_get_devices(ACPI_PROCESSOR_DEVICE_HID, user_function: early_init_pdc, NULL, NULL);
120}
121