1 /**
2  * Copyright © 2020 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 
17 #include "pmbus_write_vout_command_action.hpp"
18 
19 #include "action_error.hpp"
20 #include "pmbus_error.hpp"
21 #include "write_verification_error.hpp"
22 
23 #include <exception>
24 #include <ios>
25 #include <sstream>
26 
27 namespace phosphor::power::regulators
28 {
29 
execute(ActionEnvironment & environment)30 bool PMBusWriteVoutCommandAction::execute(ActionEnvironment& environment)
31 {
32     try
33     {
34         // Get volts value
35         double voltsValue = getVoltsValue(environment);
36 
37         // Get I2C interface to current device
38         i2c::I2CInterface& interface = getI2CInterface(environment);
39 
40         // Get exponent value for converting volts value to linear format
41         int8_t exponentValue = getExponentValue(environment, interface);
42 
43         // Convert volts value to linear data format
44         uint16_t linearValue =
45             pmbus_utils::convertToVoutLinear(voltsValue, exponentValue);
46 
47         // Write linear format value to VOUT_COMMAND.  I2CInterface method
48         // writes low-order byte first as required by PMBus.
49         interface.write(pmbus_utils::VOUT_COMMAND, linearValue);
50 
51         // Verify write if necessary
52         if (isWriteVerified)
53         {
54             verifyWrite(environment, interface, linearValue);
55         }
56     }
57     // Nest the following exception types within an ActionError so the caller
58     // will have both the low level error information and the action information
59     catch (const i2c::I2CException& i2cError)
60     {
61         std::throw_with_nested(ActionError(*this));
62     }
63     catch (const PMBusError& pmbusError)
64     {
65         std::throw_with_nested(ActionError(*this));
66     }
67     catch (const WriteVerificationError& verifyError)
68     {
69         std::throw_with_nested(ActionError(*this));
70     }
71     return true;
72 }
73 
toString() const74 std::string PMBusWriteVoutCommandAction::toString() const
75 {
76     std::ostringstream ss;
77     ss << "pmbus_write_vout_command: { ";
78 
79     if (volts.has_value())
80     {
81         ss << "volts: " << volts.value() << ", ";
82     }
83 
84     ss << "format: " << pmbus_utils::toString(format);
85 
86     if (exponent.has_value())
87     {
88         ss << ", exponent: " << static_cast<int16_t>(exponent.value());
89     }
90 
91     ss << ", is_verified: " << std::boolalpha << isWriteVerified << " }";
92     return ss.str();
93 }
94 
getExponentValue(ActionEnvironment & environment,i2c::I2CInterface & interface)95 int8_t PMBusWriteVoutCommandAction::getExponentValue(
96     ActionEnvironment& environment, i2c::I2CInterface& interface)
97 {
98     // Check if an exponent value is defined for this action
99     if (exponent.has_value())
100     {
101         return exponent.value();
102     }
103 
104     // Read value of the VOUT_MODE command
105     uint8_t voutModeValue;
106     interface.read(pmbus_utils::VOUT_MODE, voutModeValue);
107 
108     // Parse VOUT_MODE value to get data format and parameter value
109     pmbus_utils::VoutDataFormat format;
110     int8_t parameter;
111     pmbus_utils::parseVoutMode(voutModeValue, format, parameter);
112 
113     // Verify format is linear; other formats not currently supported
114     if (format != pmbus_utils::VoutDataFormat::linear)
115     {
116         throw PMBusError("VOUT_MODE contains unsupported data format",
117                          environment.getDeviceID(),
118                          environment.getDevice().getFRU());
119     }
120 
121     // Return parameter value; it contains the exponent when format is linear
122     return parameter;
123 }
124 
125 double
getVoltsValue(ActionEnvironment & environment)126     PMBusWriteVoutCommandAction::getVoltsValue(ActionEnvironment& environment)
127 {
128     double voltsValue;
129 
130     if (volts.has_value())
131     {
132         // A volts value is defined for this action
133         voltsValue = volts.value();
134     }
135     else if (environment.getVolts().has_value())
136     {
137         // A volts value is defined in the ActionEnvironment
138         voltsValue = environment.getVolts().value();
139     }
140     else
141     {
142         throw ActionError(*this, "No volts value defined");
143     }
144 
145     return voltsValue;
146 }
147 
verifyWrite(ActionEnvironment & environment,i2c::I2CInterface & interface,uint16_t valueWritten)148 void PMBusWriteVoutCommandAction::verifyWrite(ActionEnvironment& environment,
149                                               i2c::I2CInterface& interface,
150                                               uint16_t valueWritten)
151 {
152     // Read current value of VOUT_COMMAND.  I2CInterface method reads low byte
153     // first as required by PMBus.
154     uint16_t valueRead{0x00};
155     interface.read(pmbus_utils::VOUT_COMMAND, valueRead);
156 
157     // Verify value read equals value written
158     if (valueRead != valueWritten)
159     {
160         std::ostringstream ss;
161         ss << "device: " << environment.getDeviceID()
162            << ", register: VOUT_COMMAND, value_written: 0x" << std::hex
163            << std::uppercase << valueWritten << ", value_read: 0x" << valueRead;
164         throw WriteVerificationError(ss.str(), environment.getDeviceID(),
165                                      environment.getDevice().getFRU());
166     }
167 }
168 
169 } // namespace phosphor::power::regulators
170