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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 | |
17 | #include <linux/kernel.h> |
18 | #include <linux/types.h> |
19 | #include <acpi/acpi_bus.h> |
20 | #include <acpi/acpi_drivers.h> |
21 | #include <asm/xen/hypercall.h> |
22 | #include <xen/interface/version.h> |
23 | #include <xen/xen-ops.h> |
24 | |
25 | #define ACPI_PROCESSOR_AGGREGATOR_CLASS "acpi_pad" |
26 | #define ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME "Processor Aggregator" |
27 | #define ACPI_PROCESSOR_AGGREGATOR_NOTIFY 0x80 |
28 | static DEFINE_MUTEX(xen_cpu_lock); |
29 | |
30 | static int xen_acpi_pad_idle_cpus(unsigned int idle_nums) |
31 | { |
32 | struct xen_platform_op op; |
33 | |
34 | op.cmd = XENPF_core_parking; |
35 | op.u.core_parking.type = XEN_CORE_PARKING_SET; |
36 | op.u.core_parking.idle_nums = idle_nums; |
37 | |
38 | return HYPERVISOR_dom0_op(&op); |
39 | } |
40 | |
41 | static int xen_acpi_pad_idle_cpus_num(void) |
42 | { |
43 | struct xen_platform_op op; |
44 | |
45 | op.cmd = XENPF_core_parking; |
46 | op.u.core_parking.type = XEN_CORE_PARKING_GET; |
47 | |
48 | return HYPERVISOR_dom0_op(&op) |
49 | ?: op.u.core_parking.idle_nums; |
50 | } |
51 | |
52 | /* |
53 | * Query firmware how many CPUs should be idle |
54 | * return -1 on failure |
55 | */ |
56 | static int acpi_pad_pur(acpi_handle handle) |
57 | { |
58 | struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL}; |
59 | union acpi_object *package; |
60 | int num = -1; |
61 | |
62 | if (ACPI_FAILURE(acpi_evaluate_object(handle, "_PUR", NULL, &buffer))) |
63 | return num; |
64 | |
65 | if (!buffer.length || !buffer.pointer) |
66 | return num; |
67 | |
68 | package = buffer.pointer; |
69 | |
70 | if (package->type == ACPI_TYPE_PACKAGE && |
71 | package->package.count == 2 && |
72 | package->package.elements[0].integer.value == 1) /* rev 1 */ |
73 | num = package->package.elements[1].integer.value; |
74 | |
75 | kfree(buffer.pointer); |
76 | return num; |
77 | } |
78 | |
79 | /* Notify firmware how many CPUs are idle */ |
80 | static void acpi_pad_ost(acpi_handle handle, int stat, |
81 | uint32_t idle_nums) |
82 | { |
83 | union acpi_object params[3] = { |
84 | {.type = ACPI_TYPE_INTEGER,}, |
85 | {.type = ACPI_TYPE_INTEGER,}, |
86 | {.type = ACPI_TYPE_BUFFER,}, |
87 | }; |
88 | struct acpi_object_list arg_list = {3, params}; |
89 | |
90 | params[0].integer.value = ACPI_PROCESSOR_AGGREGATOR_NOTIFY; |
91 | params[1].integer.value = stat; |
92 | params[2].buffer.length = 4; |
93 | params[2].buffer.pointer = (void *)&idle_nums; |
94 | acpi_evaluate_object(handle, "_OST", &arg_list, NULL); |
95 | } |
96 | |
97 | static void acpi_pad_handle_notify(acpi_handle handle) |
98 | { |
99 | int idle_nums; |
100 | |
101 | mutex_lock(&xen_cpu_lock); |
102 | idle_nums = acpi_pad_pur(handle); |
103 | if (idle_nums < 0) { |
104 | mutex_unlock(&xen_cpu_lock); |
105 | return; |
106 | } |
107 | |
108 | idle_nums = xen_acpi_pad_idle_cpus(idle_nums) |
109 | ?: xen_acpi_pad_idle_cpus_num(); |
110 | if (idle_nums >= 0) |
111 | acpi_pad_ost(handle, 0, idle_nums); |
112 | mutex_unlock(&xen_cpu_lock); |
113 | } |
114 | |
115 | static void acpi_pad_notify(acpi_handle handle, u32 event, |
116 | void *data) |
117 | { |
118 | switch (event) { |
119 | case ACPI_PROCESSOR_AGGREGATOR_NOTIFY: |
120 | acpi_pad_handle_notify(handle); |
121 | break; |
122 | default: |
123 | pr_warn("Unsupported event [0x%x]\n", event); |
124 | break; |
125 | } |
126 | } |
127 | |
128 | static int acpi_pad_add(struct acpi_device *device) |
129 | { |
130 | acpi_status status; |
131 | |
132 | strcpy(acpi_device_name(device), ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME); |
133 | strcpy(acpi_device_class(device), ACPI_PROCESSOR_AGGREGATOR_CLASS); |
134 | |
135 | status = acpi_install_notify_handler(device->handle, |
136 | ACPI_DEVICE_NOTIFY, acpi_pad_notify, device); |
137 | if (ACPI_FAILURE(status)) |
138 | return -ENODEV; |
139 | |
140 | return 0; |
141 | } |
142 | |
143 | static int acpi_pad_remove(struct acpi_device *device) |
144 | { |
145 | mutex_lock(&xen_cpu_lock); |
146 | xen_acpi_pad_idle_cpus(0); |
147 | mutex_unlock(&xen_cpu_lock); |
148 | |
149 | acpi_remove_notify_handler(device->handle, |
150 | ACPI_DEVICE_NOTIFY, acpi_pad_notify); |
151 | return 0; |
152 | } |
153 | |
154 | static const struct acpi_device_id pad_device_ids[] = { |
155 | {"ACPI000C", 0}, |
156 | {"", 0}, |
157 | }; |
158 | |
159 | static struct acpi_driver acpi_pad_driver = { |
160 | .name = "processor_aggregator", |
161 | .class = ACPI_PROCESSOR_AGGREGATOR_CLASS, |
162 | .ids = pad_device_ids, |
163 | .ops = { |
164 | .add = acpi_pad_add, |
165 | .remove = acpi_pad_remove, |
166 | }, |
167 | }; |
168 | |
169 | static int __init xen_acpi_pad_init(void) |
170 | { |
171 | /* Only DOM0 is responsible for Xen acpi pad */ |
172 | if (!xen_initial_domain()) |
173 | return -ENODEV; |
174 | |
175 | /* Only Xen4.2 or later support Xen acpi pad */ |
176 | if (!xen_running_on_version_or_later(4, 2)) |
177 | return -ENODEV; |
178 | |
179 | return acpi_bus_register_driver(&acpi_pad_driver); |
180 | } |
181 | subsys_initcall(xen_acpi_pad_init); |
182 |
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