[Mellanox] SFP new platform API implementation (#2944)

* add sfp new api

* fix get presence

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

@@ -15,15 +15,24 @@ try:
     from sonic_platform.psu import Psu
     from sonic_platform.fan import Fan
     from sonic_platform.fan import FAN_PATH
+    from sonic_platform.sfp import SFP
     from sonic_platform.watchdog import get_watchdog
     from os import listdir
     from os.path import isfile, join
     import re
+    import subprocess
 except ImportError as e:
     raise ImportError (str(e) + "- required module not found")
 
 MLNX_NUM_PSU = 2
 
+GET_HWSKU_CMD = "sonic-cfggen -d -v DEVICE_METADATA.localhost.hwsku"
+
+# magic code defnition for port number, qsfp port position of each hwsku
+# port_position_tuple = (PORT_START, QSFP_PORT_START, PORT_END, PORT_IN_BLOCK, EEPROM_OFFSET)
+hwsku_dict = {'ACS-MSN2700': 0, "LS-SN2700":0, 'ACS-MSN2740': 0, 'ACS-MSN2100': 1, 'ACS-MSN2410': 2, 'ACS-MSN2010': 3, 'ACS-MSN3700': 0, 'ACS-MSN3700C': 0, 'Mellanox-SN2700': 0, 'Mellanox-SN2700-D48C8': 0}
+port_position_tuple_list = [(0, 0, 31, 32, 1), (0, 0, 15, 16, 1), (0, 48, 55, 56, 1),(0, 18, 21, 22, 1)]
+
 class Chassis(ChassisBase):
     """Platform-specific Chassis class"""
 
@@ -50,6 +59,20 @@ class Chassis(ChassisBase):
                 fan = Fan(index, index)
             self._fan_list.append(fan)
 
+        # Initialize SFP list
+        port_position_tuple = self._get_port_position_tuple_by_sku_name()
+        self.PORT_START = port_position_tuple[0]
+        self.QSFP_PORT_START = port_position_tuple[1]
+        self.PORT_END = port_position_tuple[2]
+        self.PORTS_IN_BLOCK = port_position_tuple[3]
+        
+        for index in range(self.PORT_START, self.PORT_END + 1):
+            if index in range(QSFP_PORT_START, self.PORTS_IN_BLOCK + 1):
+                sfp_module = SFP(index, 'QSFP')
+            else:
+                sfp_module = SFP(index, 'SFP')
+            self._psu_list.append(sfp_module)
+
     def _extract_num_of_fans_and_fan_drawers(self):
         num_of_fan = 0
         num_of_drawer = 0
@@ -66,5 +89,11 @@ class Chassis(ChassisBase):
 
         return num_of_fan, num_of_drawer
 
+    def _get_port_position_tuple_by_sku_name(self):
+        p = subprocess.Popen(GET_HWSKU_CMD, shell=True, stdout=subprocess.PIPE)
+        out, err = p.communicate()
+        position_tuple = port_position_tuple_list[hwsku_dict[out.rstrip('\n')]]
+        return position_tuple
+