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 <fmt/format.h>
22 
23 #include <phosphor-logging/log.hpp>
24 
25 #include <algorithm>
26 
27 namespace phosphor
28 {
29 namespace fan
30 {
31 namespace presence
32 {
33 
34 void Fallback::stateChanged(bool present, PresenceSensor& sensor)
35 {
36     if (!present)
37     {
38         // Starting with the first backup, find the first
39         // sensor that reports the fan as present, if any.
40         auto it = std::find_if(std::next(activeSensor), sensors.end(),
41                                [](auto& s) { return s.get().present(); });
42 
43         if (it != sensors.end())
44         {
45             // A backup sensor disagrees with the active sensor.
46             // Switch to the backup.
47             activeSensor->get().stop();
48             present = it->get().start();
49 
50             while (activeSensor != it)
51             {
52                 // Callout the broken sensors.
53                 activeSensor->get().fail();
54                 ++activeSensor;
55             }
56             phosphor::logging::log<phosphor::logging::level::INFO>(
57                 fmt::format("Using backup presence sensor for fan {}",
58                             std::get<1>(fan))
59                     .c_str());
60             activeSensor = it;
61         }
62     }
63 
64     setPresence(fan, present);
65 }
66 
67 void Fallback::monitor()
68 {
69     // Find the first sensor that says the fan is present
70     // and set it as the active sensor.
71     activeSensor = std::find_if(sensors.begin(), sensors.end(),
72                                 [](auto& s) { return s.get().present(); });
73     if (activeSensor == sensors.end())
74     {
75         // The first sensor is working or all sensors
76         // agree the fan isn't present.  Use the first sensor.
77         activeSensor = sensors.begin();
78     }
79 
80     if (activeSensor != sensors.begin())
81     {
82         phosphor::logging::log<phosphor::logging::level::INFO>(
83             fmt::format("Using backup presence sensor for fan {}",
84                         std::get<1>(fan))
85                 .c_str());
86     }
87 
88     // Callout the broken sensors.
89     auto it = sensors.begin();
90     while (it != activeSensor)
91     {
92         it->get().fail();
93         ++it;
94     }
95 
96     // Start the active sensor and set the initial state.
97     setPresence(fan, activeSensor->get().start());
98 }
99 
100 } // namespace presence
101 } // namespace fan
102 } // namespace phosphor
103