Add support of mdio IPC server class using sai switch api and unix so…

…cket (sonic-net#1080)

Why I did it
When MDIO devices (external PHYs) are connected on MDIO bus from NPU, the MDIO access is through SAI switch mdio read/write APIs. The syncd calling the SAI APIs needs to act as an IPC server so that the gbsyncd programming the MDIO devices can use the APIs by the IPC mechanism.

How I did it
MdioIpcServer class is added to start a new thread, to create an unix socket, to listen on the socket, to accept connection and to read/reply IPC messages. The corresponding functions for MDIO clause 45 and clause 22 access are also added to VendorSai class.

How to verify it
We can use socat to simulate the IPC client, e.g.
docker exec -it syncd socat - UNIX-CONNECT:/var/run/sswsyncd/mdio-ipc.srv
to read MDIO clause 45 register at an address and an offset
mdio <address> <reg offset>
to write MDIO clause 45 register at an address and an offset with a value
mdio <address> <reg offset> <value>
to read MDIO clause 22 register at an address and an offset
mdio-cl22 <address> <reg offset>
to write MDIO clause 22 register at an address and an offset with a value
mdio-cl22 <address> <reg offset> <value>

Signed-off-by: Jiahua Wang <jiahua.wang@broadcom.com>

configure.ac

@@ -16,6 +16,7 @@ AX_CODE_COVERAGE
 AX_ADD_AM_MACRO_STATIC([])
 
 AM_CONDITIONAL(SONIC_ASIC_PLATFORM_BAREFOOT,   test x$CONFIGURED_PLATFORM = xbarefoot)
+AM_CONDITIONAL(SONIC_ASIC_PLATFORM_BROADCOM,   test x$CONFIGURED_PLATFORM = xbroadcom)
 
 AC_ARG_ENABLE(debug,
 [  --enable-debug          turn on debugging],

meta/SaiInterface.cpp

@@ -197,3 +197,51 @@ sai_status_t SaiInterface::get(
             return SAI_STATUS_FAILURE;
     }
 }
+
+sai_status_t SaiInterface::switchMdioRead(
+        _In_ sai_object_id_t switch_id,
+        _In_ uint32_t device_addr,
+        _In_ uint32_t start_reg_addr,
+        _In_ uint32_t number_of_registers,
+        _Out_ uint32_t *reg_val)
+{
+    SWSS_LOG_ENTER();
+
+    return SAI_STATUS_FAILURE;
+}
+
+sai_status_t SaiInterface::switchMdioWrite(
+        _In_ sai_object_id_t switch_id,
+        _In_ uint32_t device_addr,
+        _In_ uint32_t start_reg_addr,
+        _In_ uint32_t number_of_registers,
+        _In_ const uint32_t *reg_val)
+{
+    SWSS_LOG_ENTER();
+
+    return SAI_STATUS_FAILURE;
+}
+
+sai_status_t SaiInterface::switchMdioCl22Read(
+        _In_ sai_object_id_t switch_id,
+        _In_ uint32_t device_addr,
+        _In_ uint32_t start_reg_addr,
+        _In_ uint32_t number_of_registers,
+        _Out_ uint32_t *reg_val)
+{
+    SWSS_LOG_ENTER();
+
+    return SAI_STATUS_FAILURE;
+}
+
+sai_status_t SaiInterface::switchMdioCl22Write(
+        _In_ sai_object_id_t switch_id,
+        _In_ uint32_t device_addr,
+        _In_ uint32_t start_reg_addr,
+        _In_ uint32_t number_of_registers,
+        _In_ const uint32_t *reg_val)
+{
+    SWSS_LOG_ENTER();
+
+    return SAI_STATUS_FAILURE;
+}

meta/SaiInterface.h

@@ -222,6 +222,34 @@ namespace sairedis
                     _In_ uint32_t attrCount,
                     _In_ const sai_attribute_t *attrList) = 0;
 
+            virtual sai_status_t switchMdioRead(
+                    _In_ sai_object_id_t switch_id,
+                    _In_ uint32_t device_addr,
+                    _In_ uint32_t start_reg_addr,
+                    _In_ uint32_t number_of_registers,
+                    _Out_ uint32_t *reg_val);
+
+            virtual sai_status_t switchMdioWrite(
+                    _In_ sai_object_id_t switch_id,
+                    _In_ uint32_t device_addr,
+                    _In_ uint32_t start_reg_addr,
+                    _In_ uint32_t number_of_registers,
+                    _In_ const uint32_t *reg_val);
+
+            virtual sai_status_t switchMdioCl22Read(
+                    _In_ sai_object_id_t switch_id,
+                    _In_ uint32_t device_addr,
+                    _In_ uint32_t start_reg_addr,
+                    _In_ uint32_t number_of_registers,
+                    _Out_ uint32_t *reg_val);
+
+            virtual sai_status_t switchMdioCl22Write(
+                    _In_ sai_object_id_t switch_id,
+                    _In_ uint32_t device_addr,
+                    _In_ uint32_t start_reg_addr,
+                    _In_ uint32_t number_of_registers,
+                    _In_ const uint32_t *reg_val);
+
         public: // SAI API
 
             virtual sai_status_t objectTypeGetAvailability(

syncd/Makefile.am

@@ -23,6 +23,7 @@ libSyncd_a_SOURCES = \
 				FlexCounterManager.cpp \
 				GlobalSwitchId.cpp \
 				HardReiniter.cpp \
+				MdioIpcServer.cpp \
 				MetadataLogger.cpp \
 				NotificationHandler.cpp \
 				NotificationProcessor.cpp \
@@ -71,6 +72,10 @@ syncd_CXXFLAGS += -DSAITHRIFT=yes
 syncd_LDADD += -lrpcserver -lthrift
 endif
 
+if SONIC_ASIC_PLATFORM_BROADCOM
+libSyncd_a_CXXFLAGS += -DMDIO_ACCESS_USE_NPU
+endif
+
 libSyncdRequestShutdown_a_SOURCES = \
 									RequestShutdown.cpp \
 									RequestShutdownCommandLineOptions.cpp \