power-utils: Retrieve Firmware Version from sysfs

Added support to retrieve firmware version from sysfs. This required the
following code additions and modifications:

1 - Locate the target PSU object and retrieve 'i2cBus' and 'i2cAddress'.
2 - Obtain PMBus interface access.
3 - Read the firmware version from sysfs.

Tested:
  The new code was loaded onto a system, and the firmware version was
  successfully read from sysfs. Verified getVersion using psu.json file
  did not change.

Change-Id: I791788f45e4d682578efbed33e3832a833644dad
Signed-off-by: Faisal Awada <faisal@us.ibm.com>
diff --git a/tools/power-utils/main.cpp b/tools/power-utils/main.cpp
index ed63071..eb81db4 100644
--- a/tools/power-utils/main.cpp
+++ b/tools/power-utils/main.cpp
@@ -13,13 +13,17 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+#include "config.h"
+
 #include "updater.hpp"
 #include "version.hpp"
 
 #include <CLI/CLI.hpp>
 #include <phosphor-logging/log.hpp>
+#include <sdbusplus/bus.hpp>
 
 #include <cassert>
+#include <filesystem>
 
 using namespace phosphor::logging;
 
@@ -47,9 +51,18 @@
 
     std::string ret;
 
+    bool useJsonFile = version::utils::checkFileExists(PSU_JSON_PATH);
+    auto bus = sdbusplus::bus::new_default();
     if (!psuPath.empty())
     {
-        ret = version::getVersion(psuPath);
+        if (!useJsonFile)
+        {
+            ret = version::getVersion(bus, psuPath);
+        }
+        else
+        {
+            ret = version::getVersion(psuPath);
+        }
     }
     if (!versions.empty())
     {
diff --git a/tools/power-utils/version.cpp b/tools/power-utils/version.cpp
index 93b9a82..1987342 100644
--- a/tools/power-utils/version.cpp
+++ b/tools/power-utils/version.cpp
@@ -21,19 +21,30 @@
 #include "utility.hpp"
 
 #include <phosphor-logging/log.hpp>
+#include <xyz/openbmc_project/Common/Device/error.hpp>
 
+#include <exception>
+#include <iostream>
+#include <regex>
+#include <stdexcept>
 #include <tuple>
 
 using json = nlohmann::json;
 
 using namespace phosphor::logging;
 
-// PsuInfo contains the device path, pmbus read type, and the version string
-using PsuVersionInfo =
-    std::tuple<std::string, phosphor::pmbus::Type, std::string>;
+using namespace phosphor::power::util;
+using namespace sdbusplus::xyz::openbmc_project::Common::Device::Error;
 
+namespace version
+{
 namespace utils
 {
+constexpr auto IBMCFFPSInterface =
+    "xyz.openbmc_project.Configuration.IBMCFFPSConnector";
+constexpr auto i2cBusProp = "I2CBus";
+constexpr auto i2cAddressProp = "I2CAddress";
+
 PsuVersionInfo getVersionInfo(const std::string& psuInventoryPath)
 {
     auto data = phosphor::power::util::loadJSONFromFile(PSU_JSON_PATH);
@@ -90,10 +101,134 @@
     return latest;
 }
 
-} // namespace utils
-
-namespace version
+PsuI2cInfo getPsuI2c(sdbusplus::bus_t& bus, const std::string& psuInventoryPath)
 {
+    auto depth = 0;
+    auto objects = getSubTree(bus, "/", IBMCFFPSInterface, depth);
+    if (objects.empty())
+    {
+        throw std::runtime_error("Supported Configuration Not Found");
+    }
+
+    std::optional<std::uint64_t> i2cbus;
+    std::optional<std::uint64_t> i2caddr;
+
+    // GET a map of objects back.
+    // Each object will have a path, a service, and an interface.
+    for (const auto& [path, services] : objects)
+    {
+        auto service = services.begin()->first;
+
+        if (path.empty() || service.empty())
+        {
+            continue;
+        }
+
+        // Match the PSU identifier in the path with the passed PSU inventory
+        // path. Compare the last character of both paths to find the PSU bus
+        // and address. example: PSU path:
+        // /xyz/openbmc_project/inventory/system/board/Nisqually_Backplane/Power_Supply_Slot_0
+        // PSU inventory path:
+        // /xyz/openbmc_project/inventory/system/chassis/motherboard/powersupply0
+        if (path.back() == psuInventoryPath.back())
+        {
+            // Retrieve i2cBus and i2cAddress from array of properties.
+            auto properties =
+                getAllProperties(bus, path, IBMCFFPSInterface, service);
+            for (const auto& property : properties)
+            {
+                try
+                {
+                    if (property.first == i2cBusProp)
+                    {
+                        i2cbus = std::get<uint64_t>(properties.at(i2cBusProp));
+                    }
+                    else if (property.first == i2cAddressProp)
+                    {
+                        i2caddr =
+                            std::get<uint64_t>(properties.at(i2cAddressProp));
+                    }
+                }
+                catch (const std::exception& e)
+                {
+                    log<level::WARNING>(
+                        std::format("Error reading property {}: {}",
+                                    property.first, e.what())
+                            .c_str());
+                }
+            }
+
+            if (i2cbus.has_value() && i2caddr.has_value())
+            {
+                break;
+            }
+        }
+    }
+
+    if (!i2cbus.has_value() || !i2caddr.has_value())
+    {
+        throw std::runtime_error("Failed to get I2C bus or address");
+    }
+
+    return std::make_tuple(*i2cbus, *i2caddr);
+}
+
+std::unique_ptr<phosphor::pmbus::PMBusBase>
+    getPmbusIntf(std::uint64_t i2cBus, std::uint64_t i2cAddr)
+{
+    std::stringstream ss;
+    ss << std::hex << std::setw(4) << std::setfill('0') << i2cAddr;
+    return phosphor::pmbus::createPMBus(i2cBus, ss.str());
+}
+
+std::string readVPDValue(phosphor::pmbus::PMBusBase& pmbusIntf,
+                         const std::string& vpdName,
+                         const phosphor::pmbus::Type& type,
+                         const std::size_t& vpdSize)
+{
+    std::string vpdValue;
+    const std::regex illegalVPDRegex =
+        std::regex("[^[:alnum:]]", std::regex::basic);
+
+    try
+    {
+        vpdValue = pmbusIntf.readString(vpdName, type);
+    }
+    catch (const ReadFailure& e)
+    {
+        // Ignore the read failure, let pmbus code indicate failure.
+    }
+
+    if (vpdValue.size() != vpdSize)
+    {
+        log<level::INFO>(
+            std::format(" {} resize needed. size: {}", vpdName, vpdValue.size())
+                .c_str());
+        vpdValue.resize(vpdSize, ' ');
+    }
+
+    // Replace any illegal values with space(s).
+    std::regex_replace(vpdValue.begin(), vpdValue.begin(), vpdValue.end(),
+                       illegalVPDRegex, " ");
+
+    return vpdValue;
+}
+
+bool checkFileExists(const std::string& filePath)
+{
+    try
+    {
+        return std::filesystem::exists(filePath);
+    }
+    catch (const std::exception& e)
+    {
+        log<level::ERR>(std::format("Unable to check for existence of {}: {}",
+                                    filePath, e.what())
+                            .c_str());
+    }
+    return false;
+}
+} // namespace utils
 
 std::string getVersion(const std::string& psuInventoryPath)
 {
@@ -101,7 +236,7 @@
         utils::getVersionInfo(psuInventoryPath);
     if (devicePath.empty() || versionStr.empty())
     {
-        return {};
+        return "";
     }
     std::string version;
     try
@@ -116,6 +251,36 @@
     return version;
 }
 
+std::string getVersion(sdbusplus::bus_t& bus,
+                       const std::string& psuInventoryPath)
+{
+    try
+    {
+        constexpr auto FW_VERSION = "fw_version";
+        using namespace phosphor::pmbus;
+        const auto IBMCFFPS_FW_VERSION_SIZE = 12;
+        const auto& [i2cbus, i2caddr] = utils::getPsuI2c(bus, psuInventoryPath);
+
+        auto pmbusIntf = utils::getPmbusIntf(i2cbus, i2caddr);
+
+        if (!pmbusIntf)
+        {
+            log<level::WARNING>("Unable to get pointer PMBus Interface");
+            return "";
+        }
+
+        std::string fwVersion =
+            utils::readVPDValue(*pmbusIntf, FW_VERSION, Type::HwmonDeviceDebug,
+                                IBMCFFPS_FW_VERSION_SIZE);
+        return fwVersion;
+    }
+    catch (const std::exception& e)
+    {
+        log<level::ERR>(std::format("Error: {}", e.what()).c_str());
+        return "";
+    }
+}
+
 std::string getLatest(const std::vector<std::string>& versions)
 {
     // TODO: when multiple PSU/Machines are supported, add configuration options
@@ -136,5 +301,4 @@
     // So just compare by strings is OK for these cases
     return utils::getLatestDefault(versions);
 }
-
 } // namespace version
diff --git a/tools/power-utils/version.hpp b/tools/power-utils/version.hpp
index c10071a..534d113 100644
--- a/tools/power-utils/version.hpp
+++ b/tools/power-utils/version.hpp
@@ -15,14 +15,109 @@
  */
 #pragma once
 
+#include "pmbus.hpp"
+
+#include <sdbusplus/bus.hpp>
+
+#include <memory>
 #include <string>
+#include <tuple>
 #include <vector>
 
 namespace version
 {
+namespace utils
+{
+// PsuInfo contains the device path, pmbus read type, and the version string
+using PsuVersionInfo =
+    std::tuple<std::string, phosphor::pmbus::Type, std::string>;
+
+// PsuI2cInfo contains the device i2c bus and i2c address
+using PsuI2cInfo = std::tuple<std::uint64_t, std::uint64_t>;
 
 /**
- * Get the software version of the PSU
+ * @brief Get PSU version information
+ *
+ * @param[in] psuInventoryPath - The PSU inventory path.
+ *
+ * @return tuple - device path, pmbus read type and PSU version
+ */
+PsuVersionInfo getVersionInfo(const std::string& psuInventoryPath);
+
+/**
+ * @brief Get firmware latest version
+ *
+ * @param[in] versions - String of versions
+ *
+ * @return version - latest firmware level
+ */
+std::string getLatestDefault(const std::vector<std::string>& versions);
+
+/**
+ * @brief Get i2c bus and address
+ *
+ * @param[in] bus - Systemd bus connection
+ * @param[in] psuInventoryPath - The PSU inventory path.
+ *
+ * @return tuple - i2cBus and i2cAddr.
+ */
+PsuI2cInfo getPsuI2c(sdbusplus::bus_t& bus,
+                     const std::string& psuInventoryPath);
+
+/**
+ * @brief Get PMBus interface pointer
+ *
+ * @param[in] i2cBus - PSU i2c bus
+ * @param[in] i2cAddr - PSU i2c address
+ *
+ * @return Pointer to PSU PMBus interface
+ */
+std::unique_ptr<phosphor::pmbus::PMBusBase>
+    getPmbusIntf(std::uint64_t i2cBus, std::uint64_t i2cAddr);
+
+/**
+ * @brief Reads a VPD value from PMBus, corrects size, and contents.
+ *
+ * If the VPD data read is not the passed in size, resize and fill with
+ * spaces. If the data contains a non-alphanumeric value, replace any of
+ * those values with spaces.
+ *
+ * @param[in] pmbusIntf - PMBus Interface.
+ * @param[in] vpdName - The name of the sysfs "file" to read data from.
+ * @param[in] type - The HWMON file type to read from.
+ * @param[in] vpdSize - The expected size of the data for this VPD/property
+ *
+ * @return A string containing the VPD data read, resized if necessary
+ */
+std::string readVPDValue(phosphor::pmbus::PMBusBase& pmbusIntf,
+                         const std::string& vpdName,
+                         const phosphor::pmbus::Type& type,
+                         const std::size_t& vpdSize);
+
+/**
+ * @brief Check for file existence
+ *
+ * @param[in] filePath - File path
+ *
+ * @return bool
+ */
+bool checkFileExists(const std::string& filePath);
+
+} // namespace utils
+
+/**
+ * Get the software version of the PSU using sysfs
+ *
+ * @param[in] bus - Systemd bus connection
+ * @param[in] psuInventoryPath - The inventory path of the PSU
+ *
+ * @return The version of the PSU
+ */
+std::string getVersion(sdbusplus::bus_t& bus,
+                       const std::string& psuInventoryPath);
+
+/**
+ * Get the software version of the PSU using psu.json
  *
  * @param[in] psuInventoryPath - The inventory path of the PSU
  *