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