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Liu, Jinsong92e32292012-11-08 05:41:13 +00001/*
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>
Konrad Rzeszutek Wilk394b40f2012-11-27 11:39:40 -050023#include <xen/xen-ops.h>
Liu, Jinsong92e32292012-11-08 05:41:13 +000024
25#define ACPI_PROCESSOR_AGGREGATOR_CLASS "acpi_pad"
26#define ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME "Processor Aggregator"
27#define ACPI_PROCESSOR_AGGREGATOR_NOTIFY 0x80
28static DEFINE_MUTEX(xen_cpu_lock);
29
30static 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
41static 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 */
56static 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 */
80static 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
97static 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
115static 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
128static 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
Rafael J. Wysocki51fac832013-01-24 00:24:48 +0100143static int acpi_pad_remove(struct acpi_device *device)
Liu, Jinsong92e32292012-11-08 05:41:13 +0000144{
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
154static const struct acpi_device_id pad_device_ids[] = {
155 {"ACPI000C", 0},
156 {"", 0},
157};
158
159static 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
169static 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}
181subsys_initcall(xen_acpi_pad_init);