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 | |
18 | static 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 | |
28 | static 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(size: sizeof(struct acpi_object_list), GFP_KERNEL); |
36 | if (!obj_list) |
37 | goto out; |
38 | |
39 | obj = kmalloc(size: sizeof(union acpi_object), GFP_KERNEL); |
40 | if (!obj) { |
41 | kfree(objp: obj_list); |
42 | goto out; |
43 | } |
44 | |
45 | buf = kmalloc(size: 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; |
61 | out: |
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 | */ |
70 | static acpi_status |
71 | acpi_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 | |
84 | void 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 | |
102 | static acpi_status __init |
103 | early_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 | |
112 | void __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 | |