ipmid: channel: add max transfer size property

Each channel can have a different maximum transfer size. This should be
exposed so that it is easier to tell how many bytes it is possible to
send or receive on a given channel.

Change-Id: Ie277eb7a802edc1deeefe201a7560d371920f519
Signed-off-by: Vernon Mauery <vernon.mauery@linux.intel.com>

4 files changed, 31 insertions, 0 deletions

diff --git a/user_channel/channel_layer.cpp b/user_channel/channel_layer.cpp
index d173208..4cab58f 100644
--- a/user_channel/channel_layer.cpp
+++ b/user_channel/channel_layer.cpp
@@ -79,6 +79,11 @@ int getChannelActiveSessions(const uint8_t chNum)
     return getChannelConfigObject().getChannelActiveSessions(chNum);
 }
 
+size_t getChannelMaxTransferSize(uint8_t chNum)
+{
+    return getChannelConfigObject().getChannelMaxTransferSize(chNum);
+}
+
 ipmi_ret_t ipmiChannelInit()
 {
     getChannelConfigObject();
diff --git a/user_channel/channel_layer.hpp b/user_channel/channel_layer.hpp
index abaa0bf..87e791c 100644
--- a/user_channel/channel_layer.hpp
+++ b/user_channel/channel_layer.hpp
@@ -225,6 +225,14 @@ EChannelSessSupported getChannelSessionSupport(const uint8_t chNum);
  */
 int getChannelActiveSessions(const uint8_t chNum);
 
+/** @brief determines maximum transfer size for a channel
+ *
+ *  @param[in] chNum - channel number
+ *
+ *  @return maximum bytes that can be transferred on this channel
+ */
+size_t getChannelMaxTransferSize(uint8_t chNum);
+
 /** @brief initializes channel management
  *
  *  @return IPMI_CC_OK for success, others for failure.
diff --git a/user_channel/channel_mgmt.cpp b/user_channel/channel_mgmt.cpp
index 0ece27e..310ac2b 100644
--- a/user_channel/channel_mgmt.cpp
+++ b/user_channel/channel_mgmt.cpp
@@ -62,6 +62,7 @@ static constexpr const char* propertiesChangedSignal = "PropertiesChanged";
 static constexpr const char* nameString = "name";
 static constexpr const char* isValidString = "is_valid";
 static constexpr const char* activeSessionsString = "active_sessions";
+static constexpr const char* maxTransferSizeString = "max_transfer_size";
 static constexpr const char* channelInfoString = "channel_info";
 static constexpr const char* mediumTypeString = "medium_type";
 static constexpr const char* protocolTypeString = "protocol_type";
@@ -86,6 +87,7 @@ static constexpr const uint8_t defaultSessionSupported =
 static constexpr const uint8_t defaultAuthType =
     static_cast<uint8_t>(EAuthType::none);
 static constexpr const bool defaultIsIpmiState = false;
+static constexpr size_t smallChannelSize = 64;
 
 std::unique_ptr<sdbusplus::bus::match_t> chPropertiesSignal(nullptr);
 
@@ -419,6 +421,11 @@ int ChannelConfig::getChannelActiveSessions(const uint8_t chNum)
     return channelData[chNum].activeSessCount;
 }
 
+size_t ChannelConfig::getChannelMaxTransferSize(uint8_t chNum)
+{
+    return channelData[chNum].maxTransferSize;
+}
+
 ipmi_ret_t ChannelConfig::getChannelInfo(const uint8_t chNum,
                                          ChannelInfo& chInfo)
 {
@@ -941,6 +948,8 @@ int ChannelConfig::loadChannelConfig()
                     jsonChData[isValidString].get<bool>();
                 channelData[chNum].activeSessCount =
                     jsonChData.value(activeSessionsString, 0);
+                channelData[chNum].maxTransferSize =
+                    jsonChData.value(maxTransferSizeString, smallChannelSize);
                 Json jsonChInfo = jsonChData[channelInfoString].get<Json>();
                 if (jsonChInfo.is_null())
                 {
diff --git a/user_channel/channel_mgmt.hpp b/user_channel/channel_mgmt.hpp
index d696075..3de5fa8 100644
--- a/user_channel/channel_mgmt.hpp
+++ b/user_channel/channel_mgmt.hpp
@@ -62,6 +62,7 @@ struct ChannelData
     uint8_t activeSessCount;
     ChannelInfo chInfo;
     ChannelAccessData chAccess;
+    size_t maxTransferSize;
 };
 
 class ChannelConfig;
@@ -112,6 +113,14 @@ class ChannelConfig
      */
     int getChannelActiveSessions(const uint8_t chNum);
 
+    /** @brief determines maximum transfer size for a channel
+     *
+     *  @param[in] chNum - channel number
+     *
+     *  @return maximum bytes that can be transferred on this channel
+     */
+    size_t getChannelMaxTransferSize(uint8_t chNum);
+
     /** @brief provides channel info details
      *
      *  @param[in] chNum - channel number