drm: rp1: VEC and DPI drivers: Fix bug #5901
[platform/kernel/linux-rpi.git] / drivers / xen / xen-acpi-pad.c
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * xen-acpi-pad.c - Xen pad interface
4  *
5  * Copyright (c) 2012, Intel Corporation.
6  *    Author: Liu, Jinsong <jinsong.liu@intel.com>
7  */
8
9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10
11 #include <linux/kernel.h>
12 #include <linux/types.h>
13 #include <linux/acpi.h>
14 #include <xen/xen.h>
15 #include <xen/interface/version.h>
16 #include <xen/xen-ops.h>
17 #include <asm/xen/hypercall.h>
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
32         return HYPERVISOR_platform_op(&op);
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
42         return HYPERVISOR_platform_op(&op)
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
73 static void acpi_pad_handle_notify(acpi_handle handle)
74 {
75         int idle_nums;
76         struct acpi_buffer param = {
77                 .length = 4,
78                 .pointer = (void *)&idle_nums,
79         };
80
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)
92                 acpi_evaluate_ost(handle, ACPI_PROCESSOR_AGGREGATOR_NOTIFY,
93                                   0, &param);
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
125 static void acpi_pad_remove(struct acpi_device *device)
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);
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);