[202012] [Mellanox] Fix issue: SFP eeprom corrupted after replacing cable with different sfp type (#13543)

- Why I did it
There are 3 tasks in xcvrd:

main task, run a loop to recover missing SFP static information to DB every 1 minute
SFP state task, a process which listens cable plug in/out event, insert SFP static information to DB while a cable is inserted
SFP DOM update task, a thread which handles cable DOM information update every 1 minute
Let assume user replaces QSFP with QSFP-DD. There are two issues:

Only SFP state task listens cable plug in/out event, main task and SFP DOM update task does not know SFP type has changed, they still “think” the SFP type is QSFP. So, main task and SFP DOM update task uses QSFP standard to parse QSFP-DD EEPROM which causes corrupted data.
There is a race condition between main task and SFP state task. They both insert SFP static information to DB. Depends on timing, it is possible that main task using wrong SFP type to override SFP static information.
The PR is to fix these two issues.

There is no such issue on 202205 and above because there is a refactor for xcvrd:

SFP state task was changed from process to thread, so that all 3 tasks share the same memory space, they always have correct SFP type.
Recover missing SFP information logical was moved from main task to SFP state task. There is no race condition anymore.

- How I did it
It is difficult to back port latest xcvrd because there are many refactor/new features in xcvrd after 202012 release. It will be huge effort to do so. Based on that, we decided to fix the issue on Nvidia platform API side. The fix is that: refreshing SFP type before any SFP API which accessing SFP EEPROM. Refreshing SFP type before any SFP API would cause a small performance down: Due to my test on 202012 branch, accessing transceiver INFO and DOM INFO for 32 ports takes 1.7 seconds before the change. The number changes to 2.4 seconds after the change. I suppose the performance down is acceptable.

- How to verify it
Manual test
Regression

Author: Junchao-Mellanox

platform/mellanox/mlnx-platform-api/sonic_platform/sfp.py

@@ -7,6 +7,7 @@
 #############################################################################
 
 try:
+    import functools
     import time
     from sonic_platform_base.sfp_base import SfpBase
     from sonic_platform_base.sonic_eeprom import eeprom_dts
@@ -323,6 +324,24 @@ def deinitialize_sdk_handle(sdk_handle):
          logger.log_warning("Sdk handle is none")
          return False
 
+
+def refresh_sfp_type(refresh_dom_capability=True):
+    """Decorator to force refreshing sfp type
+
+    Args:
+        refresh_dom_capability (bool, optional): refresh DOM capability. Defaults to True.
+    """
+    def decorator(method):
+        @functools.wraps(method)
+        def _impl(self, *args, **kwargs):
+            self._refresh_sfp_type()
+            if refresh_dom_capability:
+                self._dom_capability_detect()
+            return method(self, *args, **kwargs)
+        return _impl
+    return decorator
+
+
 class SFP(SfpBase):
     """Platform-specific SFP class"""
 
@@ -332,9 +351,9 @@ def __init__(self, sfp_index, sfp_type, sdk_handle_getter, platform):
         self.sdk_sysfs_page_path_header = SFP_SYSFS_PATH.format(sfp_index)
         self.sfp_eeprom_path = "qsfp{}".format(self.index)
         self.sfp_status_path = "qsfp{}_status".format(self.index)
-        self._detect_sfp_type(sfp_type)
+        self._sfp_type = None
+        self._default_sfp_type = sfp_type
         self.dom_tx_disable_supported = False
-        self._dom_capability_detect()
         self.sdk_handle_getter = sdk_handle_getter
         self.sdk_index = sfp_index
 
@@ -352,7 +371,7 @@ def reinit(self):
         Re-initialize this SFP object when a new SFP inserted
         :return: 
         """
-        self._detect_sfp_type(self.sfp_type)
+        self._refresh_sfp_type()
         self._dom_capability_detect()
 
     def get_presence(self):
@@ -382,7 +401,8 @@ def _read_eeprom_specific_bytes(self, offset, num_bytes):
             if page_num == 0:
                 page = self.sdk_sysfs_page_path_header + PATH_PAGE00
             else:
-                if self.sfp_type == SFP_TYPE and page_num == 1:
+                self._refresh_sfp_type()
+                if page_num == 1 and self.sfp_type == SFP_TYPE:
                     page = self.sdk_sysfs_page_path_header + PATH_PAGE00_A2
                 else:
                     page = self.sdk_sysfs_page_path_header + PATH_PAGE.format(page_num)
@@ -394,26 +414,33 @@ def _read_eeprom_specific_bytes(self, offset, num_bytes):
         except (OSError, IOError):
             return None
 
-    def _detect_sfp_type(self, sfp_type):
-        eeprom_raw = []
-        eeprom_raw = self._read_eeprom_specific_bytes(XCVR_TYPE_OFFSET, XCVR_TYPE_WIDTH)
-        if eeprom_raw:
-            if eeprom_raw[0] in SFP_TYPE_CODE_LIST:
-                self.sfp_type = SFP_TYPE
-            elif eeprom_raw[0] in QSFP_TYPE_CODE_LIST:
-                self.sfp_type = QSFP_TYPE
-            elif eeprom_raw[0] in QSFP_DD_TYPE_CODE_LIST:
-                self.sfp_type = QSFP_DD_TYPE
+    @property
+    def sfp_type(self):
+        if self._sfp_type is None:
+            eeprom_raw = []
+            eeprom_raw = self._read_eeprom_specific_bytes(XCVR_TYPE_OFFSET, XCVR_TYPE_WIDTH)
+            if eeprom_raw:
+                if eeprom_raw[0] in SFP_TYPE_CODE_LIST:
+                    self._sfp_type = SFP_TYPE
+                elif eeprom_raw[0] in QSFP_TYPE_CODE_LIST:
+                    self._sfp_type = QSFP_TYPE
+                elif eeprom_raw[0] in QSFP_DD_TYPE_CODE_LIST:
+                    self._sfp_type = QSFP_DD_TYPE
+                else:
+                    # we don't recognize this identifier value, treat the xSFP module as the default type
+                    self._sfp_type = self._default_sfp_type
+                    logger.log_info("Identifier value of {} module {} is {} which isn't recognized and will be treated as default type ({})".format(
+                        self._default_sfp_type, self.index, eeprom_raw[0], self._default_sfp_type
+                    ))
             else:
-                # we don't regonize this identifier value, treat the xSFP module as the default type
-                self.sfp_type = sfp_type
-                logger.log_info("Identifier value of {} module {} is {} which isn't regonized and will be treated as default type ({})".format(
-                    sfp_type, self.index, eeprom_raw[0], sfp_type
-                ))
-        else:
-            # eeprom_raw being None indicates the module is not present.
-            # in this case we treat it as the default type according to the SKU
-            self.sfp_type = sfp_type
+                # eeprom_raw being None indicates the module is not present.
+                # in this case we treat it as the default type according to the SKU
+                self._sfp_type = self._default_sfp_type
+            self._default_sfp_type = self._sfp_type
+        return self._sfp_type
+
+    def _refresh_sfp_type(self):
+        self._sfp_type = None
 
     def _is_qsfp_copper(self):
         # This function read the specification compliance byte and
@@ -537,6 +564,7 @@ def _dom_capability_detect(self):
                 self.dom_supported = False
                 self.dom_temp_supported = False
                 self.dom_volt_supported = False
+                self.second_application_list = False
                 self.dom_rx_power_supported = False
                 self.dom_tx_power_supported = False
                 self.dom_tx_bias_power_supported = False
@@ -595,7 +623,7 @@ def _convert_string_to_num(self, value_str):
         else:
             return 'N/A'
 
-
+    @refresh_sfp_type()
     def get_transceiver_info(self):
         """
         Retrieves transceiver info of this SFP
@@ -900,7 +928,7 @@ def get_transceiver_info(self):
 
         return transceiver_info_dict
 
-
+    @refresh_sfp_type()
     def get_transceiver_bulk_status(self):
         """
         Retrieves transceiver bulk status of this SFP
@@ -1100,7 +1128,7 @@ def get_transceiver_bulk_status(self):
 
         return transceiver_dom_info_dict
 
-
+    @refresh_sfp_type()
     def get_transceiver_threshold_info(self):
         """
         Retrieves transceiver threshold info of this SFP
@@ -1279,7 +1307,7 @@ def get_transceiver_threshold_info(self):
 
         return transceiver_dom_threshold_info_dict
 
-
+    @refresh_sfp_type()
     def get_reset_status(self):
         """
         Retrieves the reset status of SFP
@@ -1332,6 +1360,7 @@ def get_reset_status(self):
             dom_channel_status_data = sfpd_obj.parse_dom_channel_status(dom_channel_status_raw, 0)
             return dom_channel_status_data['data']['Status']['value'] == 'On'
 
+    @refresh_sfp_type()
     def get_rx_los(self):
         """
         Retrieves the RX LOS (lost-of-signal) status of SFP
@@ -1364,7 +1393,7 @@ def get_rx_los(self):
             rx_los_list.append(False)
         return rx_los_list
 
-
+    @refresh_sfp_type()
     def get_tx_fault(self):
         """
         Retrieves the TX fault status of SFP
@@ -1397,7 +1426,7 @@ def get_tx_fault(self):
             tx_fault_list.append(False)
         return tx_fault_list
 
-
+    @refresh_sfp_type()
     def get_tx_disable(self):
         """
         Retrieves the tx_disable status of this SFP
@@ -1500,7 +1529,7 @@ def get_lpmode(self):
 
         return oper_pwr_mode == SX_MGMT_PHY_MOD_PWR_MODE_LOW_E
 
-
+    @refresh_sfp_type(refresh_dom_capability=True)
     def get_power_override(self):
         """
         Retrieves the power-override status of this SFP
@@ -1521,7 +1550,7 @@ def get_power_override(self):
         else:
             return NotImplementedError
 
-
+    @refresh_sfp_type()
     def get_temperature(self):
         """
         Retrieves the temperature of this SFP
@@ -1579,7 +1608,7 @@ def get_temperature(self):
             else:
                 return None
 
-
+    @refresh_sfp_type()
     def get_voltage(self):
         """
         Retrieves the supply voltage of this SFP
@@ -1638,7 +1667,7 @@ def get_voltage(self):
             else:
                 return None
 
-
+    @refresh_sfp_type()
     def get_tx_bias(self):
         """
         Retrieves the TX bias current of this SFP
@@ -1672,7 +1701,7 @@ def get_tx_bias(self):
                 if sfpd_obj is None:
                     return None
 
-                if dom_tx_bias_power_supported:
+                if self.dom_tx_bias_power_supported:
                     dom_tx_bias_raw = self._read_eeprom_specific_bytes((offset + QSFP_DD_TX_BIAS_OFFSET), QSFP_DD_TX_BIAS_WIDTH)
                     if dom_tx_bias_raw is not None:
                         dom_tx_bias_data = sfpd_obj.parse_dom_tx_bias(dom_tx_bias_raw, 0)
@@ -1705,7 +1734,7 @@ def get_tx_bias(self):
 
         return tx_bias_list
 
-
+    @refresh_sfp_type()
     def get_rx_power(self):
         """
         Retrieves the received optical power for this SFP
@@ -1781,7 +1810,7 @@ def get_rx_power(self):
                 return None
         return rx_power_list
 
-
+    @refresh_sfp_type()
     def get_tx_power(self):
         """
         Retrieves the TX power of this SFP