[CMIS] Reject loopback mode requests when simultaneous host-media loo…

…pback is not supported and conflicting modes are active

Signed-off-by: xinyu <xinyu0123@gmail.com>

sonic_platform_base/sonic_xcvr/api/public/cmis.py

@@ -1133,34 +1133,42 @@ def set_loopback_mode(self, loopback_mode, lane_mask = 0xff):
         loopback_capability = self.get_loopback_capability()
         if loopback_capability is None:
             return False
+
+        status_host_input = self.xcvr_eeprom.read(consts.HOST_INPUT_LOOPBACK)
+        status_host_output = self.xcvr_eeprom.read(consts.HOST_OUTPUT_LOOPBACK)
+        status_media_input = self.xcvr_eeprom.read(consts.MEDIA_INPUT_LOOPBACK)
+        status_media_output = self.xcvr_eeprom.read(consts.MEDIA_OUTPUT_LOOPBACK)
+
         if loopback_mode == 'none':
             status_host_input = self.xcvr_eeprom.write(consts.HOST_INPUT_LOOPBACK, 0)
             status_host_output = self.xcvr_eeprom.write(consts.HOST_OUTPUT_LOOPBACK, 0)
             status_media_input = self.xcvr_eeprom.write(consts.MEDIA_INPUT_LOOPBACK, 0)
             status_media_output = self.xcvr_eeprom.write(consts.MEDIA_OUTPUT_LOOPBACK, 0)
             return all([status_host_input, status_host_output, status_media_input, status_media_output])
-        elif loopback_mode == 'host-side-input':
-            if loopback_capability['host_side_input_loopback_supported']:
-                return self.xcvr_eeprom.write(consts.HOST_INPUT_LOOPBACK, lane_mask)
-            else:
-                return False
-        elif loopback_mode == 'host-side-output':
-            if loopback_capability['host_side_output_loopback_supported']:
-                return self.xcvr_eeprom.write(consts.HOST_OUTPUT_LOOPBACK, lane_mask)
-            else:
-                return False
-        elif loopback_mode == 'media-side-input':
-            if loopback_capability['media_side_input_loopback_supported']:
-                return self.xcvr_eeprom.write(consts.MEDIA_INPUT_LOOPBACK, lane_mask)
-            else:
-                return False
-        elif loopback_mode == 'media-side-output':
-            if loopback_capability['media_side_output_loopback_supported']:
-                return self.xcvr_eeprom.write(consts.MEDIA_OUTPUT_LOOPBACK, lane_mask)
-            else:
-                return False
         else:
-            return False
+            if loopback_capability['simultaneous_host_media_loopback_supported'] is False:
+                if loopback_mode in ['host-side-input', 'host-side-output'] and \
+                   (status_media_input or status_media_output):
+                    return False
+
+                if loopback_mode in ['media-side-input', 'media-side-output'] and \
+                   (status_host_output or status_host_input):
+                    return False
+
+            if loopback_mode == 'host-side-input':
+                if loopback_capability['host_side_input_loopback_supported']:
+                    return self.xcvr_eeprom.write(consts.HOST_INPUT_LOOPBACK, lane_mask)
+            elif loopback_mode == 'host-side-output':
+                if loopback_capability['host_side_output_loopback_supported']:
+                    return self.xcvr_eeprom.write(consts.HOST_OUTPUT_LOOPBACK, lane_mask)
+            elif loopback_mode == 'media-side-input':
+                if loopback_capability['media_side_input_loopback_supported']:
+                    return self.xcvr_eeprom.write(consts.MEDIA_INPUT_LOOPBACK, lane_mask)
+            elif loopback_mode == 'media-side-output':
+                if loopback_capability['media_side_output_loopback_supported']:
+                    return self.xcvr_eeprom.write(consts.MEDIA_OUTPUT_LOOPBACK, lane_mask)
+
+        return False
 
     def get_vdm(self, field_option=None):
         '''

tests/sonic_xcvr/test_cmis.py

@@ -1057,31 +1057,36 @@ def test_get_loopback_capability(self, mock_response, expected):
             'host_side_input_loopback_supported': True,
             'host_side_output_loopback_supported': True,
             'media_side_input_loopback_supported': True,
-            'media_side_output_loopback_supported': True
+            'media_side_output_loopback_supported': True,
+            'simultaneous_host_media_loopback_supported': True
         }),
         ('host-side-input', {
             'host_side_input_loopback_supported': True,
             'host_side_output_loopback_supported': True,
             'media_side_input_loopback_supported': True,
-            'media_side_output_loopback_supported': True
+            'media_side_output_loopback_supported': True,
+            'simultaneous_host_media_loopback_supported': True
         }),
         ('host-side-output', {
             'host_side_input_loopback_supported': True,
             'host_side_output_loopback_supported': True,
             'media_side_input_loopback_supported': True,
-            'media_side_output_loopback_supported': True
+            'media_side_output_loopback_supported': True,
+            'simultaneous_host_media_loopback_supported': False
         }),
         ('media-side-input', {
             'host_side_input_loopback_supported': True,
             'host_side_output_loopback_supported': True,
             'media_side_input_loopback_supported': True,
-            'media_side_output_loopback_supported': True
+            'media_side_output_loopback_supported': True,
+            'simultaneous_host_media_loopback_supported': False
         }),
         ('media-side-output', {
             'host_side_input_loopback_supported': True,
             'host_side_output_loopback_supported': True,
             'media_side_input_loopback_supported': True,
-            'media_side_output_loopback_supported': True
+            'media_side_output_loopback_supported': True,
+            'simultaneous_host_media_loopback_supported': True
         }),
         (
             'none', None