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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
Joe Perches283c0972013-06-28 03:21:41 -070017#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
18
Liu, Jinsong92e32292012-11-08 05:41:13 +000019#include <linux/kernel.h>
20#include <linux/types.h>
Lv Zheng8b484632013-12-03 08:49:16 +080021#include <linux/acpi.h>
Liu, Jinsong92e32292012-11-08 05:41:13 +000022#include <xen/interface/version.h>
Konrad Rzeszutek Wilk394b40f2012-11-27 11:39:40 -050023#include <xen/xen-ops.h>
Lv Zheng8b484632013-12-03 08:49:16 +080024#include <asm/xen/hypercall.h>
Liu, Jinsong92e32292012-11-08 05:41:13 +000025
26#define ACPI_PROCESSOR_AGGREGATOR_CLASS "acpi_pad"
27#define ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME "Processor Aggregator"
28#define ACPI_PROCESSOR_AGGREGATOR_NOTIFY 0x80
29static DEFINE_MUTEX(xen_cpu_lock);
30
31static int xen_acpi_pad_idle_cpus(unsigned int idle_nums)
32{
33 struct xen_platform_op op;
34
35 op.cmd = XENPF_core_parking;
36 op.u.core_parking.type = XEN_CORE_PARKING_SET;
37 op.u.core_parking.idle_nums = idle_nums;
38
39 return HYPERVISOR_dom0_op(&op);
40}
41
42static int xen_acpi_pad_idle_cpus_num(void)
43{
44 struct xen_platform_op op;
45
46 op.cmd = XENPF_core_parking;
47 op.u.core_parking.type = XEN_CORE_PARKING_GET;
48
49 return HYPERVISOR_dom0_op(&op)
50 ?: op.u.core_parking.idle_nums;
51}
52
53/*
54 * Query firmware how many CPUs should be idle
55 * return -1 on failure
56 */
57static int acpi_pad_pur(acpi_handle handle)
58{
59 struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
60 union acpi_object *package;
61 int num = -1;
62
63 if (ACPI_FAILURE(acpi_evaluate_object(handle, "_PUR", NULL, &buffer)))
64 return num;
65
66 if (!buffer.length || !buffer.pointer)
67 return num;
68
69 package = buffer.pointer;
70
71 if (package->type == ACPI_TYPE_PACKAGE &&
72 package->package.count == 2 &&
73 package->package.elements[0].integer.value == 1) /* rev 1 */
74 num = package->package.elements[1].integer.value;
75
76 kfree(buffer.pointer);
77 return num;
78}
79
Liu, Jinsong92e32292012-11-08 05:41:13 +000080static void acpi_pad_handle_notify(acpi_handle handle)
81{
82 int idle_nums;
Jiang Liu772c5392014-02-19 14:02:17 +080083 struct acpi_buffer param = {
84 .length = 4,
85 .pointer = (void *)&idle_nums,
86 };
87
Liu, Jinsong92e32292012-11-08 05:41:13 +000088
89 mutex_lock(&xen_cpu_lock);
90 idle_nums = acpi_pad_pur(handle);
91 if (idle_nums < 0) {
92 mutex_unlock(&xen_cpu_lock);
93 return;
94 }
95
96 idle_nums = xen_acpi_pad_idle_cpus(idle_nums)
97 ?: xen_acpi_pad_idle_cpus_num();
98 if (idle_nums >= 0)
Jiang Liu772c5392014-02-19 14:02:17 +080099 acpi_evaluate_ost(handle, ACPI_PROCESSOR_AGGREGATOR_NOTIFY,
100 0, &param);
Liu, Jinsong92e32292012-11-08 05:41:13 +0000101 mutex_unlock(&xen_cpu_lock);
102}
103
104static void acpi_pad_notify(acpi_handle handle, u32 event,
105 void *data)
106{
107 switch (event) {
108 case ACPI_PROCESSOR_AGGREGATOR_NOTIFY:
109 acpi_pad_handle_notify(handle);
110 break;
111 default:
112 pr_warn("Unsupported event [0x%x]\n", event);
113 break;
114 }
115}
116
117static int acpi_pad_add(struct acpi_device *device)
118{
119 acpi_status status;
120
121 strcpy(acpi_device_name(device), ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME);
122 strcpy(acpi_device_class(device), ACPI_PROCESSOR_AGGREGATOR_CLASS);
123
124 status = acpi_install_notify_handler(device->handle,
125 ACPI_DEVICE_NOTIFY, acpi_pad_notify, device);
126 if (ACPI_FAILURE(status))
127 return -ENODEV;
128
129 return 0;
130}
131
Rafael J. Wysocki51fac832013-01-24 00:24:48 +0100132static int acpi_pad_remove(struct acpi_device *device)
Liu, Jinsong92e32292012-11-08 05:41:13 +0000133{
134 mutex_lock(&xen_cpu_lock);
135 xen_acpi_pad_idle_cpus(0);
136 mutex_unlock(&xen_cpu_lock);
137
138 acpi_remove_notify_handler(device->handle,
139 ACPI_DEVICE_NOTIFY, acpi_pad_notify);
140 return 0;
141}
142
143static const struct acpi_device_id pad_device_ids[] = {
144 {"ACPI000C", 0},
145 {"", 0},
146};
147
148static struct acpi_driver acpi_pad_driver = {
149 .name = "processor_aggregator",
150 .class = ACPI_PROCESSOR_AGGREGATOR_CLASS,
151 .ids = pad_device_ids,
152 .ops = {
153 .add = acpi_pad_add,
154 .remove = acpi_pad_remove,
155 },
156};
157
158static int __init xen_acpi_pad_init(void)
159{
160 /* Only DOM0 is responsible for Xen acpi pad */
161 if (!xen_initial_domain())
162 return -ENODEV;
163
164 /* Only Xen4.2 or later support Xen acpi pad */
165 if (!xen_running_on_version_or_later(4, 2))
166 return -ENODEV;
167
168 return acpi_bus_register_driver(&acpi_pad_driver);
169}
170subsys_initcall(xen_acpi_pad_init);