1 /**
2  * Copyright © 2017 IBM Corporation
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *     http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 #include "fallback.hpp"
17 
18 #include "fan.hpp"
19 #include "psensor.hpp"
20 
21 #include <phosphor-logging/log.hpp>
22 
23 #include <algorithm>
24 
25 namespace phosphor
26 {
27 namespace fan
28 {
29 namespace presence
30 {
31 
32 void Fallback::stateChanged(bool present, PresenceSensor& sensor)
33 {
34     if (!present)
35     {
36         // Starting with the first backup, find the first
37         // sensor that reports the fan as present, if any.
38         auto it = std::find_if(std::next(activeSensor), sensors.end(),
39                                [](auto& s) { return s.get().present(); });
40 
41         if (it != sensors.end())
42         {
43             // A backup sensor disagrees with the active sensor.
44             // Switch to the backup.
45             activeSensor->get().stop();
46             present = it->get().start();
47 
48             while (activeSensor != it)
49             {
50                 // Callout the broken sensors.
51                 activeSensor->get().fail();
52                 ++activeSensor;
53             }
54             phosphor::logging::log<phosphor::logging::level::INFO>(
55                 "Using backup presence sensor.",
56                 phosphor::logging::entry("FAN=%s", std::get<1>(fan).c_str()));
57             activeSensor = it;
58         }
59     }
60 
61     setPresence(fan, present);
62 }
63 
64 void Fallback::monitor()
65 {
66     // Find the first sensor that says the fan is present
67     // and set it as the active sensor.
68     activeSensor = std::find_if(sensors.begin(), sensors.end(),
69                                 [](auto& s) { return s.get().present(); });
70     if (activeSensor == sensors.end())
71     {
72         // The first sensor is working or all sensors
73         // agree the fan isn't present.  Use the first sensor.
74         activeSensor = sensors.begin();
75     }
76 
77     if (activeSensor != sensors.begin())
78     {
79         phosphor::logging::log<phosphor::logging::level::INFO>(
80             "Using backup presence sensor.",
81             phosphor::logging::entry("FAN=%s", std::get<1>(fan).c_str()));
82     }
83 
84     // Callout the broken sensors.
85     auto it = sensors.begin();
86     while (it != activeSensor)
87     {
88         it->get().fail();
89         ++it;
90     }
91 
92     // Start the active sensor and set the initial state.
93     setPresence(fan, activeSensor->get().start());
94 }
95 
96 } // namespace presence
97 } // namespace fan
98 } // namespace phosphor
99