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2025cf9e | 1 | // SPDX-License-Identifier: GPL-2.0-only |
92e3229d LJ |
2 | /* |
3 | * xen-acpi-pad.c - Xen pad interface | |
4 | * | |
5 | * Copyright (c) 2012, Intel Corporation. | |
6 | * Author: Liu, Jinsong <jinsong.liu@intel.com> | |
92e3229d LJ |
7 | */ |
8 | ||
283c0972 JP |
9 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
10 | ||
92e3229d LJ |
11 | #include <linux/kernel.h> |
12 | #include <linux/types.h> | |
8b48463f | 13 | #include <linux/acpi.h> |
3cfa210b | 14 | #include <xen/xen.h> |
92e3229d | 15 | #include <xen/interface/version.h> |
394b40f6 | 16 | #include <xen/xen-ops.h> |
8b48463f | 17 | #include <asm/xen/hypercall.h> |
92e3229d LJ |
18 | |
19 | #define ACPI_PROCESSOR_AGGREGATOR_CLASS "acpi_pad" | |
20 | #define ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME "Processor Aggregator" | |
21 | #define ACPI_PROCESSOR_AGGREGATOR_NOTIFY 0x80 | |
22 | static DEFINE_MUTEX(xen_cpu_lock); | |
23 | ||
24 | static int xen_acpi_pad_idle_cpus(unsigned int idle_nums) | |
25 | { | |
26 | struct xen_platform_op op; | |
27 | ||
28 | op.cmd = XENPF_core_parking; | |
29 | op.u.core_parking.type = XEN_CORE_PARKING_SET; | |
30 | op.u.core_parking.idle_nums = idle_nums; | |
31 | ||
cfafae94 | 32 | return HYPERVISOR_platform_op(&op); |
92e3229d LJ |
33 | } |
34 | ||
35 | static int xen_acpi_pad_idle_cpus_num(void) | |
36 | { | |
37 | struct xen_platform_op op; | |
38 | ||
39 | op.cmd = XENPF_core_parking; | |
40 | op.u.core_parking.type = XEN_CORE_PARKING_GET; | |
41 | ||
cfafae94 | 42 | return HYPERVISOR_platform_op(&op) |
92e3229d LJ |
43 | ?: op.u.core_parking.idle_nums; |
44 | } | |
45 | ||
46 | /* | |
47 | * Query firmware how many CPUs should be idle | |
48 | * return -1 on failure | |
49 | */ | |
50 | static int acpi_pad_pur(acpi_handle handle) | |
51 | { | |
52 | struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL}; | |
53 | union acpi_object *package; | |
54 | int num = -1; | |
55 | ||
56 | if (ACPI_FAILURE(acpi_evaluate_object(handle, "_PUR", NULL, &buffer))) | |
57 | return num; | |
58 | ||
59 | if (!buffer.length || !buffer.pointer) | |
60 | return num; | |
61 | ||
62 | package = buffer.pointer; | |
63 | ||
64 | if (package->type == ACPI_TYPE_PACKAGE && | |
65 | package->package.count == 2 && | |
66 | package->package.elements[0].integer.value == 1) /* rev 1 */ | |
67 | num = package->package.elements[1].integer.value; | |
68 | ||
69 | kfree(buffer.pointer); | |
70 | return num; | |
71 | } | |
72 | ||
92e3229d LJ |
73 | static void acpi_pad_handle_notify(acpi_handle handle) |
74 | { | |
75 | int idle_nums; | |
772c5399 JL |
76 | struct acpi_buffer param = { |
77 | .length = 4, | |
78 | .pointer = (void *)&idle_nums, | |
79 | }; | |
80 | ||
92e3229d LJ |
81 | |
82 | mutex_lock(&xen_cpu_lock); | |
83 | idle_nums = acpi_pad_pur(handle); | |
84 | if (idle_nums < 0) { | |
85 | mutex_unlock(&xen_cpu_lock); | |
86 | return; | |
87 | } | |
88 | ||
89 | idle_nums = xen_acpi_pad_idle_cpus(idle_nums) | |
90 | ?: xen_acpi_pad_idle_cpus_num(); | |
91 | if (idle_nums >= 0) | |
772c5399 JL |
92 | acpi_evaluate_ost(handle, ACPI_PROCESSOR_AGGREGATOR_NOTIFY, |
93 | 0, ¶m); | |
92e3229d LJ |
94 | mutex_unlock(&xen_cpu_lock); |
95 | } | |
96 | ||
97 | static void acpi_pad_notify(acpi_handle handle, u32 event, | |
98 | void *data) | |
99 | { | |
100 | switch (event) { | |
101 | case ACPI_PROCESSOR_AGGREGATOR_NOTIFY: | |
102 | acpi_pad_handle_notify(handle); | |
103 | break; | |
104 | default: | |
105 | pr_warn("Unsupported event [0x%x]\n", event); | |
106 | break; | |
107 | } | |
108 | } | |
109 | ||
110 | static int acpi_pad_add(struct acpi_device *device) | |
111 | { | |
112 | acpi_status status; | |
113 | ||
114 | strcpy(acpi_device_name(device), ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME); | |
115 | strcpy(acpi_device_class(device), ACPI_PROCESSOR_AGGREGATOR_CLASS); | |
116 | ||
117 | status = acpi_install_notify_handler(device->handle, | |
118 | ACPI_DEVICE_NOTIFY, acpi_pad_notify, device); | |
119 | if (ACPI_FAILURE(status)) | |
120 | return -ENODEV; | |
121 | ||
122 | return 0; | |
123 | } | |
124 | ||
6c0eb5ba | 125 | static void acpi_pad_remove(struct acpi_device *device) |
92e3229d LJ |
126 | { |
127 | mutex_lock(&xen_cpu_lock); | |
128 | xen_acpi_pad_idle_cpus(0); | |
129 | mutex_unlock(&xen_cpu_lock); | |
130 | ||
131 | acpi_remove_notify_handler(device->handle, | |
132 | ACPI_DEVICE_NOTIFY, acpi_pad_notify); | |
92e3229d LJ |
133 | } |
134 | ||
135 | static const struct acpi_device_id pad_device_ids[] = { | |
136 | {"ACPI000C", 0}, | |
137 | {"", 0}, | |
138 | }; | |
139 | ||
140 | static struct acpi_driver acpi_pad_driver = { | |
141 | .name = "processor_aggregator", | |
142 | .class = ACPI_PROCESSOR_AGGREGATOR_CLASS, | |
143 | .ids = pad_device_ids, | |
144 | .ops = { | |
145 | .add = acpi_pad_add, | |
146 | .remove = acpi_pad_remove, | |
147 | }, | |
148 | }; | |
149 | ||
150 | static int __init xen_acpi_pad_init(void) | |
151 | { | |
152 | /* Only DOM0 is responsible for Xen acpi pad */ | |
153 | if (!xen_initial_domain()) | |
154 | return -ENODEV; | |
155 | ||
156 | /* Only Xen4.2 or later support Xen acpi pad */ | |
157 | if (!xen_running_on_version_or_later(4, 2)) | |
158 | return -ENODEV; | |
159 | ||
160 | return acpi_bus_register_driver(&acpi_pad_driver); | |
161 | } | |
162 | subsys_initcall(xen_acpi_pad_init); |