[SFP-Refactor] Implement CMIS Low Power mode (#237)

* [SFP-Refactor] Implement CMIS LP mode

Author: aravindmani-1

sonic_platform_base/sonic_xcvr/api/public/c_cmis.py

@@ -122,11 +122,11 @@ def set_laser_freq(self, freq):
         assert channel_number % 3 == 0
         if channel_number > hi_ch_num or channel_number < low_ch_num:
             raise ValueError('Provisioned frequency out of range. Max Freq: 196100; Min Freq: 191300 GHz.')
-        self.set_low_power(True)
+        self.set_lpmode(True)
         time.sleep(5)
         status = self.xcvr_eeprom.write(consts.LASER_CONFIG_CHANNEL, channel_number)
         time.sleep(1)
-        self.set_low_power(False)
+        self.set_lpmode(False)
         time.sleep(1)
         return status
 

sonic_platform_base/sonic_xcvr/api/public/cmis.py

@@ -871,15 +871,41 @@ def reset_module(self, reset = False):
         else:
             return True
 
-    def set_low_power(self, AssertLowPower):
+    def get_lpmode(self):
+        '''
+        Retrieves Low power module status
+        Returns True if module in low power else returns False.
+        '''
+        if self.is_flat_memory() or not self.get_lpmode_support():
+            return False
+
+        lpmode = self.xcvr_eeprom.read(consts.TRANS_MODULE_STATUS_FIELD)
+        if lpmode is not None:
+            if lpmode.get('ModuleState') == 'ModuleLowPwr':
+                return True
+        return False
+
+    def set_lpmode(self, lpmode):
         '''
         This function sets the module to low power state.
-        AssertLowPower being 0 means "set to high power"
-        AssertLowPower being 1 means "set to low power"
+        lpmode being False means "set to high power"
+        lpmode being True means "set to low power"
         Return True if the provision succeeds, False if it fails
         '''
-        low_power_control = AssertLowPower << 6
-        return self.xcvr_eeprom.write(consts.MODULE_LEVEL_CONTROL, low_power_control)
+
+        if self.is_flat_memory() or not self.get_lpmode_support():
+            return False
+
+        lpmode_val = self.xcvr_eeprom.read(consts.MODULE_LEVEL_CONTROL)
+        if lpmode_val is not None:
+            if lpmode is True:
+                lpmode_val = lpmode_val | (1 << 4)
+            else:
+                lpmode_val = lpmode_val & ~(1 << 4)
+            self.xcvr_eeprom.write(consts.MODULE_LEVEL_CONTROL, lpmode_val)
+            time.sleep(0.1)
+            return self.get_lpmode()
+        return False
 
     def get_loopback_capability(self):
         '''

sonic_platform_base/sonic_xcvr/fields/consts.py

@@ -260,7 +260,7 @@
 LASER_TUNING_DETAIL = "TxTuningDetail"
 
 # CONFIG
-TRANS_CONFIG_FIELD = "TransceriverConfig"
+TRANS_CONFIG_FIELD = "TransceiverConfig"
 MODULE_LEVEL_CONTROL = "ModuleControl"
 
 CTRLS_ADVT_FIELD = "Supported Controls Advertisement"

sonic_platform_base/sonic_xcvr/sfp_optoe_base.py

@@ -128,6 +128,24 @@ def set_power_override(self, power_override, power_set):
     def get_eeprom_path(self):
         raise NotImplementedError
 
+    def get_lpmode(self):
+        """
+        This common API is applicable only for CMIS as Low Power mode can be verified
+        using EEPROM registers.For other media types like QSFP28/QSFP+ etc., platform
+        vendors has to implement accordingly.
+        """
+        api = self.get_xcvr_api()
+        return api.get_lpmode() if api is not None else None
+
+    def set_lpmode(self, lpmode):
+        """
+        This common API is applicable only for CMIS as Low Power mode can be controlled 
+        via EEPROM registers.For other media types like QSFP28/QSFP+ etc., platform
+        vendors has to implement accordingly.
+        """
+        api = self.get_xcvr_api()
+        return api.set_lp_mode(lpmode) if api is not None else None
+
     def read_eeprom(self, offset, num_bytes):
         try:
             with open(self.get_eeprom_path(), mode='rb', buffering=0) as f:

tests/sonic_xcvr/test_ccmis.py

@@ -97,6 +97,10 @@ def test_get_supported_freq_config(self, mock_response, expected):
         (195950, (0xff, -72, 120, 191300, 196100)),
     ])
     def test_set_laser_freq(self, input_param, mock_response):
+        self.api.is_flat_memory = MagicMock()
+        self.api.is_flat_memory.return_value = False
+        self.api.get_lpmode_support = MagicMock()
+        self.api.get_lpmode_support.return_value = False
         self.api.get_supported_freq_config = MagicMock()
         self.api.get_supported_freq_config.return_value = mock_response
         self.api.set_laser_freq(input_param)

tests/sonic_xcvr/test_cmis.py

@@ -747,8 +747,12 @@ def test_get_supported_power_config(self, mock_response, expected):
     def test_reset_module(self):
         self.api.reset_module(True)
 
-    def test_set_low_power(self, ):
-        self.api.set_low_power(True)
+    def test_set_low_power(self):
+        self.api.is_flat_memory = MagicMock()
+        self.api.is_flat_memory.return_value = False
+        self.api.get_lpmode_support = MagicMock()
+        self.api.get_lpmode_support.return_value = False
+        self.api.set_lpmode(True)
 
     @pytest.mark.parametrize("mock_response, expected", [
         (127,