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 "record_manager.hpp"
17 
18 #include <math.h>
19 
20 #include <phosphor-logging/log.hpp>
21 
22 #include <chrono>
23 
24 namespace phosphor
25 {
26 namespace power
27 {
28 namespace history
29 {
30 
31 using namespace phosphor::logging;
32 
33 bool RecordManager::add(const std::vector<uint8_t>& rawRecord)
34 {
35     if (rawRecord.size() == 0)
36     {
37         // The PS has no data - either the power supply just started up,
38         // or it just got a SYNC.  Clear the history.
39         records.clear();
40         return true;
41     }
42 
43     try
44     {
45         // Peek at the ID to see if more processing is needed.
46         auto id = getRawRecordID(rawRecord);
47 
48         if (!records.empty())
49         {
50             auto previousID = std::get<recIDPos>(records.front());
51 
52             // Already have this record.  Done.
53             if (previousID == id)
54             {
55                 return false;
56             }
57 
58             // Check that the sequence ID is in order.
59             // If not, clear out current list.
60             if ((previousID + 1) != id)
61             {
62                 // If it just rolled over from 0xFF to 0x00, then no
63                 // need to clear.  If we see a 0 seemingly out of nowhere,
64                 // then it was a sync so clear the old records.
65                 auto rolledOver =
66                     (previousID == lastSequenceID) && (id == FIRST_SEQUENCE_ID);
67 
68                 if (!rolledOver)
69                 {
70                     if (id != FIRST_SEQUENCE_ID)
71                     {
72                         log<level::INFO>(
73                             "Noncontiguous INPUT_HISTORY sequence ID "
74                             "found. Clearing old entries",
75                             entry("OLD_ID=%ld", previousID),
76                             entry("NEW_ID=%ld", id));
77                     }
78                     records.clear();
79                 }
80             }
81         }
82 
83         records.push_front(std::move(createRecord(rawRecord)));
84 
85         // If no more should be stored, prune the oldest
86         if (records.size() > maxRecords)
87         {
88             records.pop_back();
89         }
90     }
91     catch (InvalidRecordException& e)
92     {
93         return false;
94     }
95 
96     return true;
97 }
98 
99 auto RecordManager::getAverageRecords() -> DBusRecordList
100 {
101     DBusRecordList list;
102 
103     for (const auto& r : records)
104     {
105         list.emplace_back(std::get<recTimePos>(r), std::get<recAvgPos>(r));
106     }
107 
108     return list;
109 }
110 
111 auto RecordManager::getMaximumRecords() -> DBusRecordList
112 {
113     DBusRecordList list;
114 
115     for (const auto& r : records)
116     {
117         list.emplace_back(std::get<recTimePos>(r), std::get<recMaxPos>(r));
118     }
119 
120     return list;
121 }
122 
123 size_t RecordManager::getRawRecordID(const std::vector<uint8_t>& data) const
124 {
125     if (data.size() != RAW_RECORD_SIZE)
126     {
127         log<level::ERR>("Invalid INPUT_HISTORY size",
128                         entry("SIZE=%d", data.size()));
129         throw InvalidRecordException{};
130     }
131 
132     return data[RAW_RECORD_ID_OFFSET];
133 }
134 
135 Record RecordManager::createRecord(const std::vector<uint8_t>& data)
136 {
137     // The raw record format is:
138     //  0xAABBCCDDEE
139     //
140     //  where:
141     //    0xAA = sequence ID
142     //    0xBBCC = average power in linear format (0xCC = MSB)
143     //    0xDDEE = maximum power in linear format (0xEE = MSB)
144     auto id = getRawRecordID(data);
145 
146     auto time = std::chrono::duration_cast<std::chrono::milliseconds>(
147                     std::chrono::system_clock::now().time_since_epoch())
148                     .count();
149 
150     auto val = static_cast<uint16_t>(data[2]) << 8 | data[1];
151     auto averagePower = linearToInteger(val);
152 
153     val = static_cast<uint16_t>(data[4]) << 8 | data[3];
154     auto maxPower = linearToInteger(val);
155 
156     return Record{id, time, averagePower, maxPower};
157 }
158 
159 int64_t RecordManager::linearToInteger(uint16_t data)
160 {
161     // The exponent is the first 5 bits, followed by 11 bits of mantissa.
162     int8_t exponent = (data & 0xF800) >> 11;
163     int16_t mantissa = (data & 0x07FF);
164 
165     // If exponent's MSB on, then it's negative.
166     // Convert from two's complement.
167     if (exponent & 0x10)
168     {
169         exponent = (~exponent) & 0x1F;
170         exponent = (exponent + 1) * -1;
171     }
172 
173     // If mantissa's MSB on, then it's negative.
174     // Convert from two's complement.
175     if (mantissa & 0x400)
176     {
177         mantissa = (~mantissa) & 0x07FF;
178         mantissa = (mantissa + 1) * -1;
179     }
180 
181     auto value = static_cast<float>(mantissa) * pow(2, exponent);
182     return value;
183 }
184 
185 } // namespace history
186 } // namespace power
187 } // namespace phosphor
188