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92e3229d LJ |
1 | /* |
2 | * xen-acpi-pad.c - Xen pad interface | |
3 | * | |
4 | * Copyright (c) 2012, Intel Corporation. | |
5 | * Author: Liu, Jinsong <jinsong.liu@intel.com> | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify it | |
8 | * under the terms and conditions of the GNU General Public License, | |
9 | * version 2, as published by the Free Software Foundation. | |
10 | * | |
11 | * This program is distributed in the hope it will be useful, but WITHOUT | |
12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
14 | * more details. | |
15 | */ | |
16 | ||
283c0972 JP |
17 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
18 | ||
92e3229d LJ |
19 | #include <linux/kernel.h> |
20 | #include <linux/types.h> | |
21 | #include <acpi/acpi_bus.h> | |
22 | #include <acpi/acpi_drivers.h> | |
23 | #include <asm/xen/hypercall.h> | |
24 | #include <xen/interface/version.h> | |
394b40f6 | 25 | #include <xen/xen-ops.h> |
92e3229d LJ |
26 | |
27 | #define ACPI_PROCESSOR_AGGREGATOR_CLASS "acpi_pad" | |
28 | #define ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME "Processor Aggregator" | |
29 | #define ACPI_PROCESSOR_AGGREGATOR_NOTIFY 0x80 | |
30 | static DEFINE_MUTEX(xen_cpu_lock); | |
31 | ||
32 | static int xen_acpi_pad_idle_cpus(unsigned int idle_nums) | |
33 | { | |
34 | struct xen_platform_op op; | |
35 | ||
36 | op.cmd = XENPF_core_parking; | |
37 | op.u.core_parking.type = XEN_CORE_PARKING_SET; | |
38 | op.u.core_parking.idle_nums = idle_nums; | |
39 | ||
40 | return HYPERVISOR_dom0_op(&op); | |
41 | } | |
42 | ||
43 | static int xen_acpi_pad_idle_cpus_num(void) | |
44 | { | |
45 | struct xen_platform_op op; | |
46 | ||
47 | op.cmd = XENPF_core_parking; | |
48 | op.u.core_parking.type = XEN_CORE_PARKING_GET; | |
49 | ||
50 | return HYPERVISOR_dom0_op(&op) | |
51 | ?: op.u.core_parking.idle_nums; | |
52 | } | |
53 | ||
54 | /* | |
55 | * Query firmware how many CPUs should be idle | |
56 | * return -1 on failure | |
57 | */ | |
58 | static int acpi_pad_pur(acpi_handle handle) | |
59 | { | |
60 | struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL}; | |
61 | union acpi_object *package; | |
62 | int num = -1; | |
63 | ||
64 | if (ACPI_FAILURE(acpi_evaluate_object(handle, "_PUR", NULL, &buffer))) | |
65 | return num; | |
66 | ||
67 | if (!buffer.length || !buffer.pointer) | |
68 | return num; | |
69 | ||
70 | package = buffer.pointer; | |
71 | ||
72 | if (package->type == ACPI_TYPE_PACKAGE && | |
73 | package->package.count == 2 && | |
74 | package->package.elements[0].integer.value == 1) /* rev 1 */ | |
75 | num = package->package.elements[1].integer.value; | |
76 | ||
77 | kfree(buffer.pointer); | |
78 | return num; | |
79 | } | |
80 | ||
81 | /* Notify firmware how many CPUs are idle */ | |
82 | static void acpi_pad_ost(acpi_handle handle, int stat, | |
83 | uint32_t idle_nums) | |
84 | { | |
85 | union acpi_object params[3] = { | |
86 | {.type = ACPI_TYPE_INTEGER,}, | |
87 | {.type = ACPI_TYPE_INTEGER,}, | |
88 | {.type = ACPI_TYPE_BUFFER,}, | |
89 | }; | |
90 | struct acpi_object_list arg_list = {3, params}; | |
91 | ||
92 | params[0].integer.value = ACPI_PROCESSOR_AGGREGATOR_NOTIFY; | |
93 | params[1].integer.value = stat; | |
94 | params[2].buffer.length = 4; | |
95 | params[2].buffer.pointer = (void *)&idle_nums; | |
96 | acpi_evaluate_object(handle, "_OST", &arg_list, NULL); | |
97 | } | |
98 | ||
99 | static void acpi_pad_handle_notify(acpi_handle handle) | |
100 | { | |
101 | int idle_nums; | |
102 | ||
103 | mutex_lock(&xen_cpu_lock); | |
104 | idle_nums = acpi_pad_pur(handle); | |
105 | if (idle_nums < 0) { | |
106 | mutex_unlock(&xen_cpu_lock); | |
107 | return; | |
108 | } | |
109 | ||
110 | idle_nums = xen_acpi_pad_idle_cpus(idle_nums) | |
111 | ?: xen_acpi_pad_idle_cpus_num(); | |
112 | if (idle_nums >= 0) | |
113 | acpi_pad_ost(handle, 0, idle_nums); | |
114 | mutex_unlock(&xen_cpu_lock); | |
115 | } | |
116 | ||
117 | static void acpi_pad_notify(acpi_handle handle, u32 event, | |
118 | void *data) | |
119 | { | |
120 | switch (event) { | |
121 | case ACPI_PROCESSOR_AGGREGATOR_NOTIFY: | |
122 | acpi_pad_handle_notify(handle); | |
123 | break; | |
124 | default: | |
125 | pr_warn("Unsupported event [0x%x]\n", event); | |
126 | break; | |
127 | } | |
128 | } | |
129 | ||
130 | static int acpi_pad_add(struct acpi_device *device) | |
131 | { | |
132 | acpi_status status; | |
133 | ||
134 | strcpy(acpi_device_name(device), ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME); | |
135 | strcpy(acpi_device_class(device), ACPI_PROCESSOR_AGGREGATOR_CLASS); | |
136 | ||
137 | status = acpi_install_notify_handler(device->handle, | |
138 | ACPI_DEVICE_NOTIFY, acpi_pad_notify, device); | |
139 | if (ACPI_FAILURE(status)) | |
140 | return -ENODEV; | |
141 | ||
142 | return 0; | |
143 | } | |
144 | ||
51fac838 | 145 | static int acpi_pad_remove(struct acpi_device *device) |
92e3229d LJ |
146 | { |
147 | mutex_lock(&xen_cpu_lock); | |
148 | xen_acpi_pad_idle_cpus(0); | |
149 | mutex_unlock(&xen_cpu_lock); | |
150 | ||
151 | acpi_remove_notify_handler(device->handle, | |
152 | ACPI_DEVICE_NOTIFY, acpi_pad_notify); | |
153 | return 0; | |
154 | } | |
155 | ||
156 | static const struct acpi_device_id pad_device_ids[] = { | |
157 | {"ACPI000C", 0}, | |
158 | {"", 0}, | |
159 | }; | |
160 | ||
161 | static struct acpi_driver acpi_pad_driver = { | |
162 | .name = "processor_aggregator", | |
163 | .class = ACPI_PROCESSOR_AGGREGATOR_CLASS, | |
164 | .ids = pad_device_ids, | |
165 | .ops = { | |
166 | .add = acpi_pad_add, | |
167 | .remove = acpi_pad_remove, | |
168 | }, | |
169 | }; | |
170 | ||
171 | static int __init xen_acpi_pad_init(void) | |
172 | { | |
173 | /* Only DOM0 is responsible for Xen acpi pad */ | |
174 | if (!xen_initial_domain()) | |
175 | return -ENODEV; | |
176 | ||
177 | /* Only Xen4.2 or later support Xen acpi pad */ | |
178 | if (!xen_running_on_version_or_later(4, 2)) | |
179 | return -ENODEV; | |
180 | ||
181 | return acpi_bus_register_driver(&acpi_pad_driver); | |
182 | } | |
183 | subsys_initcall(xen_acpi_pad_init); |