xref: /openbmc/phosphor-power/pmbus.hpp (revision fa23e330)
1 #pragma once
2 
3 #include <experimental/filesystem>
4 #include <string>
5 #include <vector>
6 
7 namespace witherspoon
8 {
9 namespace pmbus
10 {
11 
12 namespace fs = std::experimental::filesystem;
13 
14 // The file name Linux uses to capture the STATUS_WORD from pmbus.
15 constexpr auto STATUS_WORD = "status0";
16 
17 // The file name Linux uses to capture the STATUS_INPUT from pmbus.
18 constexpr auto STATUS_INPUT = "status0_input";
19 
20 // Voltage out status.
21 // Overvoltage fault or warning, Undervoltage fault or warning, maximum or
22 // minimum warning, ....
23 // Uses Page substitution
24 constexpr auto STATUS_VOUT = "statusP_vout";
25 
26 namespace status_vout
27 {
28 // Mask of bits that are only warnings
29 constexpr auto WARNING_MASK = 0x6A;
30 }
31 
32 // Current output status bits.
33 constexpr auto STATUS_IOUT = "status0_iout";
34 
35 // Manufacturing specific status bits
36 constexpr auto STATUS_MFR = "status0_mfr";
37 
38 // Reports on the status of any fans installed in position 1 and 2.
39 constexpr auto STATUS_FANS_1_2 = "status0_fans12";
40 
41 // Reports on temperature faults or warnings. Overtemperature fault,
42 // overtemperature warning, undertemperature warning, undertemperature fault.
43 constexpr auto STATUS_TEMPERATURE = "status0_temp";
44 
45 namespace status_word
46 {
47 constexpr auto VOUT_FAULT = 0x8000;
48 
49 // The IBM CFF power supply driver does map this bit to power1_alarm in the
50 // hwmon space, but since the other bits that need to be checked do not have
51 // a similar mapping, the code will just read STATUS_WORD and use bit masking
52 // to see if the INPUT FAULT OR WARNING bit is on.
53 constexpr auto INPUT_FAULT_WARN = 0x2000;
54 
55 // The bit mask representing the POWER_GOOD Negated bit of the STATUS_WORD.
56 constexpr auto POWER_GOOD_NEGATED = 0x0800;
57 
58 // The bit mask representing the FAN FAULT or WARNING bit of the STATUS_WORD.
59 // Bit 2 of the high byte of STATUS_WORD.
60 constexpr auto FAN_FAULT = 0x0400;
61 
62 // The bit mask representing the UNITI_IS_OFF bit of the STATUS_WORD.
63 constexpr auto UNIT_IS_OFF = 0x0040;
64 
65 // Bit 5 of the STATUS_BYTE, or lower byte of STATUS_WORD is used to indicate
66 // an output overvoltage fault.
67 constexpr auto VOUT_OV_FAULT = 0x0020;
68 
69 // The bit mask representing that an output overcurrent fault has occurred.
70 constexpr auto IOUT_OC_FAULT = 0x0010;
71 
72 // The IBM CFF power supply driver does map this bit to in1_alarm, however,
73 // since a number of the other bits are not mapped that way for STATUS_WORD,
74 // this code will just read the entire STATUS_WORD and use bit masking to find
75 // out if that fault is on.
76 constexpr auto VIN_UV_FAULT = 0x0008;
77 
78 // The bit mask representing the TEMPERATURE FAULT or WARNING bit of the
79 // STATUS_WORD. Bit 2 of the low byte (STATUS_BYTE).
80 constexpr auto TEMPERATURE_FAULT_WARN = 0x0004;
81 
82 }
83 
84 namespace status_temperature
85 {
86 // Overtemperature Fault
87 constexpr auto OT_FAULT = 0x80;
88 }
89 
90 /**
91  * Where the access should be done
92  */
93 enum class Type
94 {
95     Base,             // base device directory
96     Hwmon,            // hwmon directory
97     Debug,            // pmbus debug directory
98     DeviceDebug,      // device debug directory
99     HwmonDeviceDebug  // hwmon device debug directory
100 };
101 
102 /**
103  * @class PMBus
104  *
105  * This class is an interface to communicating with PMBus devices
106  * by reading and writing sysfs files.
107  *
108  * Based on the Type parameter, the accesses can either be done
109  * in the base device directory (the one passed into the constructor),
110  * or in the hwmon directory for the device.
111  */
112 class PMBus
113 {
114     public:
115 
116         PMBus() = delete;
117         ~PMBus() = default;
118         PMBus(const PMBus&) = default;
119         PMBus& operator=(const PMBus&) = default;
120         PMBus(PMBus&&) = default;
121         PMBus& operator=(PMBus&&) = default;
122 
123         /**
124          * Constructor
125          *
126          * @param[in] path - path to the sysfs directory
127          */
128         PMBus(const std::string& path) :
129             basePath(path)
130         {
131             findHwmonDir();
132         }
133 
134         /**
135          * Constructor
136          *
137          * This version is required when DeviceDebug
138          * access will be used.
139          *
140          * @param[in] path - path to the sysfs directory
141          * @param[in] driverName - the device driver name
142          * @param[in] instance - chip instance number
143          */
144         PMBus(const std::string& path,
145               const std::string& driverName,
146               size_t instance) :
147             basePath(path),
148             driverName(driverName),
149             instance(instance)
150         {
151             findHwmonDir();
152         }
153 
154         /**
155          * Reads a file in sysfs that represents a single bit,
156          * therefore doing a PMBus read.
157          *
158          * @param[in] name - path concatenated to
159          *                   basePath to read
160          * @param[in] type - Path type
161          *
162          * @return bool - false if result was 0, else true
163          */
164         bool readBit(const std::string& name, Type type);
165 
166         /**
167          * Reads a file in sysfs that represents a single bit,
168          * where the page number passed in is substituted
169          * into the name in place of the 'P' character in it.
170          *
171          * @param[in] name - path concatenated to
172          *                   basePath to read
173          * @param[in] page - page number
174          * @param[in] type - Path type
175          *
176          * @return bool - false if result was 0, else true
177          */
178         bool readBitInPage(const std::string& name,
179                            size_t page,
180                            Type type);
181         /**
182          * Checks if the file for the given name and type exists.
183          *
184          * @param[in] name   - path concatenated to basePath to read
185          * @param[in] type   - Path type
186          *
187          * @return bool - True if file exists, false if it does not.
188          */
189         bool exists(const std::string& name, Type type);
190 
191         /**
192          * Read byte(s) from file in sysfs.
193          *
194          * @param[in] name   - path concatenated to basePath to read
195          * @param[in] type   - Path type
196          *
197          * @return uint64_t - Up to 8 bytes of data read from file.
198          */
199         uint64_t read(const std::string& name, Type type);
200 
201         /**
202          * Read a string from file in sysfs.
203          *
204          * @param[in] name   - path concatenated to basePath to read
205          * @param[in] type   - Path type
206          *
207          * @return string - The data read from the file.
208          */
209         std::string readString(const std::string& name, Type type);
210 
211         /**
212          * Read data from a binary file in sysfs.
213          *
214          * @param[in] name   - path concatenated to basePath to read
215          * @param[in] type   - Path type
216          * @param[in] length - length of data to read, in bytes
217          *
218          * @return vector<uint8_t> - The data read from the file.
219          */
220         std::vector<uint8_t> readBinary(const std::string& name,
221                                         Type type,
222                                         size_t length);
223 
224         /**
225          * Writes an integer value to the file, therefore doing
226          * a PMBus write.
227          *
228          * @param[in] name - path concatenated to
229          *                   basePath to write
230          * @param[in] value - the value to write
231          * @param[in] type - Path type
232          */
233         void write(const std::string& name, int value, Type type);
234 
235         /**
236          * Returns the sysfs base path of this device
237          */
238         inline const auto& path() const
239         {
240             return basePath;
241         }
242 
243         /**
244          * Replaces the 'P' in the string passed in with
245          * the page number passed in.
246          *
247          * For example:
248          *   insertPageNum("inP_enable", 42)
249          *   returns "in42_enable"
250          *
251          * @param[in] templateName - the name string, with a 'P' in it
252          * @param[in] page - the page number to insert where the P was
253          *
254          * @return string - the new string with the page number in it
255          */
256         static std::string insertPageNum(const std::string& templateName,
257                                          size_t page);
258 
259         /**
260          * Finds the path relative to basePath to the hwmon directory
261          * for the device and stores it in hwmonRelPath.
262          */
263         void findHwmonDir();
264 
265         /**
266          * Returns the path to use for the passed in type.
267          *
268          * @param[in] type - Path type
269          *
270          * @return fs::path - the full path
271          */
272         fs::path getPath(Type type);
273 
274     private:
275 
276         /**
277          * Returns the device name
278          *
279          * This is found in the 'name' file in basePath.
280          *
281          * @return string - the device name
282          */
283         std::string getDeviceName();
284 
285         /**
286          * The sysfs device path
287          */
288         fs::path basePath;
289 
290         /**
291          * The directory name under the basePath hwmon directory
292          */
293         fs::path hwmonDir;
294 
295         /**
296          * The device driver name.  Used for finding the device
297          * debug directory.  Not required if that directory
298          * isn't used.
299          */
300         std::string driverName;
301 
302         /**
303          * The device instance number.
304          *
305          * Used in conjuction with the driver name for finding
306          * the debug directory.  Not required if that directory
307          * isn't used.
308          */
309         size_t instance = 0;
310 
311         /**
312          * The pmbus debug path with status files
313          */
314         const fs::path debugPath = "/sys/kernel/debug/";
315 
316 };
317 
318 }
319 }
320