diff --git a/hw/top_darjeeling/templates/toplevel.sv.tpl b/hw/top_darjeeling/templates/toplevel.sv.tpl
index 0805edb7ae562d..fad412efe14d94 100644
--- a/hw/top_darjeeling/templates/toplevel.sv.tpl
+++ b/hw/top_darjeeling/templates/toplevel.sv.tpl
@@ -5,6 +5,7 @@ ${gencmd}
 <%
 import re
 import topgen.lib as lib
+from reggen.params import Parameter
 from topgen.clocks import Clocks
 from topgen.resets import Resets
 
@@ -22,7 +23,15 @@ num_dio_total = top['pinmux']['io_counts']['dedicated']['inouts'] + \
                 top['pinmux']['io_counts']['dedicated']['inputs'] + \
                 top['pinmux']['io_counts']['dedicated']['outputs']
 
-num_im = sum([x["width"] if "width" in x else 1 for x in top["inter_signal"]["external"]])
+num_im = 0
+for x in top["inter_signal"]["external"]:
+    if "width" in x:
+        if isinstance(x["width"], Parameter):
+            num_im += x["width"].default
+        else:
+            num_im += x["width"]
+    else:
+        num_im += 1
 
 max_sigwidth = max([x["width"] if "width" in x else 1 for x in top["pinmux"]["ios"]])
 max_sigwidth = len("{}".format(max_sigwidth))
@@ -54,7 +63,7 @@ module top_${top["name"]} #(
 <% continue %>
   % endif
   // parameters for ${m['name']}
-  % for p_exp in [p for p in m["param_list"] if p.get("expose") == "true" ]:
+  % for p_exp in [p for p in m["param_list"] if p.get("local") == "false" and p.get("expose") == "true" ]:
 <%
     p_type = p_exp.get('type')
     p_type_word = p_type + ' ' if p_type else ''
@@ -65,7 +74,7 @@ module top_${top["name"]} #(
     params_follow = not loop.last or loop.parent.index < last_modidx_with_params
     comma_char = ',' if params_follow else ''
 %>\
-    % if 12 + len(p_lhs) + 3 + len(p_rhs) + 1 < 100:
+    % if 12 + len(p_lhs) + 3 + len(str(p_rhs)) + 1 < 100:
   parameter ${p_lhs} = ${p_rhs}${comma_char}
     % else:
   parameter ${p_lhs} =
@@ -97,7 +106,11 @@ module top_${top["name"]} #(
 
   // Inter-module Signal External type
   % for sig in top["inter_signal"]["external"]:
+    % if isinstance(sig["width"], Parameter):
+  ${lib.get_direction(sig)} ${lib.im_defname(sig)} [${sig["width"].name_top}-1:0] ${sig["signame"]},
+    % else:
   ${lib.get_direction(sig)} ${lib.im_defname(sig)} ${lib.bitarray(sig["width"],1)} ${sig["signame"]},
+    % endif
   % endfor
 
 % endif
@@ -123,6 +136,29 @@ module top_${top["name"]} #(
   // Compile-time random constants
   import top_${top["name"]}_rnd_cnst_pkg::*;
 
+  // Local Parameters
+% for m in top["module"]:
+  % if not lib.is_inst(m):
+<% continue %>
+  % endif
+  // local parameters for ${m['name']}
+  % for p_exp in [p for p in m["param_list"] if p.get("local") == "true" and p.get("expose") == "true"]:
+<%
+    p_type = p_exp.get('type')
+    p_type_word = p_type + ' ' if p_type else ''
+
+    p_lhs = f'{p_type_word}{p_exp["name_top"]}'
+    p_rhs = p_exp['default']
+%>\
+    % if 13 + len(p_lhs) + 3 + len(str(p_rhs)) + 1 < 100:
+  localparam ${p_lhs} = ${p_rhs};
+    % else:
+  localparam ${p_lhs} =
+      ${p_rhs};
+    % endif
+  % endfor
+% endfor
+
   // Signals
   logic [${num_mio_inputs - 1}:0] mio_p2d;
   logic [${num_mio_outputs - 1}:0] mio_d2p;
@@ -189,7 +225,11 @@ module top_${top["name"]} #(
   // define inter-module signals
 % endif
 % for sig in top["inter_signal"]["definitions"]:
+  % if isinstance(sig["width"], Parameter):
+  ${lib.im_defname(sig)} [${sig["width"].name_top}-1:0] ${sig["signame"]};
+  % else:
   ${lib.im_defname(sig)} ${lib.bitarray(sig["width"],1)} ${sig["signame"]};
+  % endif
 % endfor
 
 ## Mixed connection to port
@@ -215,19 +255,28 @@ module top_${top["name"]} #(
 ## Partial inter-module definition tie-off
   // define partial inter-module tie-off
 % for sig in unused_im_defs:
-  % for idx in range(sig['end_idx'], sig['width']):
+<%
+  width = sig['width'].default if isinstance(sig['width'], Parameter) else sig['width']
+%>\
+  % for idx in range(sig['end_idx'], width):
   ${lib.im_defname(sig)} unused_${sig["signame"]}${idx};
   % endfor
 % endfor
 
   // assign partial inter-module tie-off
 % for sig in unused_im_defs:
-  % for idx in range(sig['end_idx'], sig['width']):
+<%
+  width = sig['width'].default if isinstance(sig['width'], Parameter) else sig['width']
+%>\
+  % for idx in range(sig['end_idx'], width):
   assign unused_${sig["signame"]}${idx} = ${sig["signame"]}[${idx}];
   % endfor
 % endfor
 % for sig in undriven_im_defs:
-  % for idx in range(sig['end_idx'], sig['width']):
+<%
+  width = sig['width'].default if isinstance(sig['width'], Parameter) else sig['width']
+%>\
+  % for idx in range(sig['end_idx'], width):
   assign ${sig["signame"]}[${idx}] = ${sig["default"]};
   % endfor
 % endfor
diff --git a/hw/top_earlgrey/data/autogen/top_earlgrey.gen.hjson b/hw/top_earlgrey/data/autogen/top_earlgrey.gen.hjson
index ab6543f08f5814..ef33bd4c1108c9 100644
--- a/hw/top_earlgrey/data/autogen/top_earlgrey.gen.hjson
+++ b/hw/top_earlgrey/data/autogen/top_earlgrey.gen.hjson
@@ -882,6 +882,7 @@
           desc: Instantiates 2-flop synchronizers on all GPIO inputs if set to 1.
           type: bit
           default: "1"
+          local: "false"
           expose: "true"
           name_top: GpioGpioAsyncOn
         }
@@ -890,6 +891,7 @@
           desc: Enable HW straps sampling logic for GPIO inputs at initial cold boot
           type: bit
           default: "0"
+          local: "false"
           expose: "true"
           name_top: GpioGpioAsHwStrapsEn
         }
@@ -977,6 +979,7 @@
           desc: Sram Entries. Word size is 32bit width.
           type: spi_device_pkg::sram_type_e
           default: spi_device_pkg::DefaultSramType
+          local: "false"
           expose: "true"
           name_top: SpiDeviceSramType
         }
@@ -1091,6 +1094,7 @@
             '''
           type: int
           default: "0"
+          local: "false"
           expose: "true"
           name_top: I2c0InputDelayCycles
         }
@@ -1183,6 +1187,7 @@
             '''
           type: int
           default: "0"
+          local: "false"
           expose: "true"
           name_top: I2c1InputDelayCycles
         }
@@ -1275,6 +1280,7 @@
             '''
           type: int
           default: "0"
+          local: "false"
           expose: "true"
           name_top: I2c2InputDelayCycles
         }
@@ -1483,6 +1489,7 @@
           desc: VMEM file to initialize the OTP macro.
           type: ""
           default: '''""'''
+          local: "false"
           expose: "true"
           name_top: OtpCtrlMemInitFile
         }
@@ -1930,6 +1937,7 @@
             '''
           type: bit
           default: top_pkg::SecVolatileRawUnlockEn
+          local: "false"
           expose: "true"
           name_top: SecLcCtrlVolatileRawUnlockEn
         }
@@ -1938,6 +1946,7 @@
           desc: When 1, a TLUL-based DMI interface is used. When 0, a JTAG TAP is used.
           type: bit
           default: "0"
+          local: "false"
           expose: "true"
           name_top: LcCtrlUseDmiInterface
         }
@@ -2006,6 +2015,7 @@
           desc: Chip generation number.
           type: logic [15:0]
           default: 16'h 4001
+          local: "false"
           expose: "true"
           name_top: LcCtrlSiliconCreatorId
         }
@@ -2014,6 +2024,7 @@
           desc: Chip revision number.
           type: logic [15:0]
           default: 16'h 0002
+          local: "false"
           expose: "true"
           name_top: LcCtrlProductId
         }
@@ -2022,6 +2033,7 @@
           desc: Chip revision number.
           type: logic [7:0]
           default: 8'h 01
+          local: "false"
           expose: "true"
           name_top: LcCtrlRevisionId
         }
@@ -2030,6 +2042,7 @@
           desc: JTAG ID code.
           type: logic [31:0]
           default: jtag_id_pkg::LC_CTRL_JTAG_IDCODE
+          local: "false"
           expose: "true"
           name_top: LcCtrlIdcodeValue
         }
@@ -2821,6 +2834,7 @@
           desc: Stub out the core of entropy_src logic
           type: bit
           default: "0"
+          local: "false"
           expose: "true"
           name_top: UsbdevStub
         }
@@ -2829,6 +2843,7 @@
           desc: Maximum number of microseconds for the differential receiver to become operational
           type: int
           default: "100"
+          local: "false"
           expose: "true"
           name_top: UsbdevRcvrWakeTimeUs
         }
@@ -3484,6 +3499,7 @@
             '''
           type: bit
           default: 1'b1
+          local: "false"
           expose: "true"
           name_top: SecRstmgrAonCheck
         }
@@ -3492,6 +3508,7 @@
           desc: The maximum synchronization delay for parent / child reset checks.
           type: int
           default: "2"
+          local: "false"
           expose: "true"
           name_top: SecRstmgrAonMaxSyncDelay
         }
@@ -4240,6 +4257,7 @@
             '''
           type: bit
           default: top_pkg::SecVolatileRawUnlockEn
+          local: "false"
           expose: "true"
           name_top: SecPinmuxAonVolatileRawUnlockEn
         }
@@ -4248,6 +4266,7 @@
           desc: Target specific pinmux configuration.
           type: pinmux_pkg::target_cfg_t
           default: pinmux_pkg::DefaultTargetCfg
+          local: "false"
           expose: "true"
           name_top: PinmuxAonTargetCfg
         }
@@ -5119,6 +5138,7 @@
           desc: Support execution from SRAM
           type: bit
           default: "0"
+          local: "false"
           expose: "true"
           name_top: SramCtrlRetAonInstrExec
         }
@@ -5127,6 +5147,7 @@
           desc: Number of PRINCE half rounds for the SRAM scrambling feature
           type: int
           default: "3"
+          local: "false"
           expose: "true"
           name_top: SramCtrlRetAonNumPrinceRoundsHalf
         }
@@ -5350,6 +5371,7 @@
           desc: Compile-time option to enable flash scrambling
           type: bit
           default: "1"
+          local: "false"
           expose: "true"
           name_top: SecFlashCtrlScrambleEn
         }
@@ -5358,6 +5380,7 @@
           desc: Depth of program fifo
           type: int
           default: "4"
+          local: "false"
           expose: "true"
           name_top: FlashCtrlProgFifoDepth
         }
@@ -5366,6 +5389,7 @@
           desc: Depth of read fifo
           type: int
           default: "16"
+          local: "false"
           expose: "true"
           name_top: FlashCtrlRdFifoDepth
         }
@@ -5730,6 +5754,7 @@
           desc: RISC-V debug module JTAG ID code.
           type: logic [31:0]
           default: jtag_id_pkg::RV_DM_JTAG_IDCODE
+          local: "false"
           expose: "true"
           name_top: RvDmIdcodeValue
         }
@@ -5738,6 +5763,7 @@
           desc: When 1, a TLUL-based DMI interface is used. When 0, a JTAG TAP is used.
           type: bit
           default: "0"
+          local: "false"
           expose: "true"
           name_top: RvDmUseDmiInterface
         }
@@ -5753,6 +5779,7 @@
             '''
           type: bit
           default: 1'b0
+          local: "false"
           expose: "true"
           name_top: SecRvDmVolatileRawUnlockEn
         }
@@ -6158,6 +6185,7 @@
           desc: Disable (0) or enable (1) support for 192-bit key lengths (AES-192).
           type: bit
           default: 1'b1
+          local: "false"
           expose: "false"
           name_top: AesAES192Enable
         }
@@ -6170,6 +6198,7 @@
             '''
           type: bit
           default: "1"
+          local: "false"
           expose: "true"
           name_top: SecAesMasking
         }
@@ -6178,6 +6207,7 @@
           desc: Selection of the S-Box implementation. See aes_pkg.sv.
           type: aes_pkg::sbox_impl_e
           default: aes_pkg::SBoxImplDom
+          local: "false"
           expose: "true"
           name_top: SecAesSBoxImpl
         }
@@ -6190,6 +6220,7 @@
             '''
           type: int unsigned
           default: "0"
+          local: "false"
           expose: "true"
           name_top: SecAesStartTriggerDelay
         }
@@ -6203,6 +6234,7 @@
             '''
           type: bit
           default: 1'b0
+          local: "false"
           expose: "true"
           name_top: SecAesAllowForcingMasks
         }
@@ -6216,6 +6248,7 @@
             '''
           type: bit
           default: 1'b0
+          local: "false"
           expose: "true"
           name_top: SecAesSkipPRNGReseeding
         }
@@ -6449,6 +6482,7 @@
           desc: Disable(0) or enable(1) first-order masking of Keccak round.
           type: bit
           default: "1"
+          local: "false"
           expose: "true"
           name_top: KmacEnMasking
         }
@@ -6463,6 +6497,7 @@
             '''
           type: bit
           default: "0"
+          local: "false"
           expose: "true"
           name_top: KmacSwKeyMasked
         }
@@ -6477,6 +6512,7 @@
             '''
           type: int
           default: "0"
+          local: "false"
           expose: "true"
           name_top: SecKmacCmdDelay
         }
@@ -6490,6 +6526,7 @@
             '''
           type: bit
           default: "0"
+          local: "false"
           expose: "true"
           name_top: SecKmacIdleAcceptSwMsg
         }
@@ -6694,6 +6731,7 @@
           desc: Stub out the core of Otbn logic
           type: bit
           default: "0"
+          local: "false"
           expose: "true"
           name_top: OtbnStub
         }
@@ -6702,6 +6740,7 @@
           desc: Selection of the register file implementation. See otbn_pkg.sv.
           type: otbn_pkg::regfile_e
           default: otbn_pkg::RegFileFF
+          local: "false"
           expose: "true"
           name_top: OtbnRegFile
         }
@@ -6725,6 +6764,7 @@
             '''
           type: bit
           default: "0"
+          local: "false"
           expose: "true"
           name_top: SecOtbnMuteUrnd
         }
@@ -6738,6 +6778,7 @@
             '''
           type: bit
           default: "0"
+          local: "false"
           expose: "true"
           name_top: SecOtbnSkipUrndReseedAtStart
         }
@@ -6941,6 +6982,7 @@
             '''
           type: bit
           default: "0"
+          local: "false"
           expose: "true"
           name_top: KeymgrUseOtpSeedsInsteadOfFlash
         }
@@ -6949,6 +6991,7 @@
           desc: Flag indicating with kmac masking is enabled
           type: bit
           default: "1"
+          local: "false"
           expose: "true"
           name_top: KeymgrKmacEnMasking
         }
@@ -7321,6 +7364,7 @@
           desc: Selection of the S-Box implementation. See aes_pkg.sv.
           type: aes_pkg::sbox_impl_e
           default: aes_pkg::SBoxImplCanright
+          local: "false"
           expose: "true"
           name_top: CsrngSBoxImpl
         }
@@ -7452,6 +7496,7 @@
           desc: Number of 384-bit entries in the esfinal FIFO
           type: int
           default: "3"
+          local: "false"
           expose: "true"
           name_top: EntropySrcEsFifoDepth
         }
@@ -7460,6 +7505,7 @@
           desc: Number of 32-bit entries in the distr FIFO
           type: int unsigned
           default: "2"
+          local: "false"
           expose: "true"
           name_top: EntropySrcDistrFifoDepth
         }
@@ -7468,6 +7514,7 @@
           desc: Stub out the core of entropy_src logic
           type: bit
           default: "0"
+          local: "false"
           expose: "true"
           name_top: EntropySrcStub
         }
@@ -7873,6 +7920,7 @@
           desc: Support execution from SRAM
           type: bit
           default: "1"
+          local: "false"
           expose: "true"
           name_top: SramCtrlMainInstrExec
         }
@@ -7881,6 +7929,7 @@
           desc: Number of PRINCE half rounds for the SRAM scrambling feature
           type: int
           default: "2"
+          local: "false"
           expose: "true"
           name_top: SramCtrlMainNumPrinceRoundsHalf
         }
@@ -8034,6 +8083,7 @@
           desc: Contents of ROM
           type: ""
           default: '''""'''
+          local: "false"
           expose: "true"
           name_top: RomCtrlBootRomInitFile
         }
@@ -8068,6 +8118,7 @@
             '''
           type: bit
           default: 1'b0
+          local: "false"
           expose: "true"
           name_top: SecRomCtrlDisableScrambling
         }
@@ -8287,6 +8338,7 @@
           desc: Enable PMP
           type: bit
           default: "1"
+          local: "false"
           expose: "true"
           name_top: RvCoreIbexPMPEnable
         }
@@ -8295,6 +8347,7 @@
           desc: PMP Granularity
           type: int unsigned
           default: "0"
+          local: "false"
           expose: "true"
           name_top: RvCoreIbexPMPGranularity
         }
@@ -8303,6 +8356,7 @@
           desc: PMP number of regions
           type: int unsigned
           default: "16"
+          local: "false"
           expose: "true"
           name_top: RvCoreIbexPMPNumRegions
         }
@@ -8311,6 +8365,7 @@
           desc: "Number of the MHPM counter "
           type: int unsigned
           default: "2"
+          local: "false"
           expose: "true"
           name_top: RvCoreIbexMHPMCounterNum
         }
@@ -8319,6 +8374,7 @@
           desc: "Width of the MHPM Counter "
           type: int unsigned
           default: "32"
+          local: "false"
           expose: "true"
           name_top: RvCoreIbexMHPMCounterWidth
         }
@@ -8327,6 +8383,7 @@
           desc: RV32E
           type: bit
           default: "0"
+          local: "false"
           expose: "true"
           name_top: RvCoreIbexRV32E
         }
@@ -8335,6 +8392,7 @@
           desc: RV32M
           type: ibex_pkg::rv32m_e
           default: ibex_pkg::RV32MSingleCycle
+          local: "false"
           expose: "true"
           name_top: RvCoreIbexRV32M
         }
@@ -8343,6 +8401,7 @@
           desc: RV32B
           type: ibex_pkg::rv32b_e
           default: ibex_pkg::RV32BOTEarlGrey
+          local: "false"
           expose: "true"
           name_top: RvCoreIbexRV32B
         }
@@ -8351,6 +8410,7 @@
           desc: Reg file
           type: ibex_pkg::regfile_e
           default: ibex_pkg::RegFileFF
+          local: "false"
           expose: "true"
           name_top: RvCoreIbexRegFile
         }
@@ -8359,6 +8419,7 @@
           desc: Branch target ALU
           type: bit
           default: "1"
+          local: "false"
           expose: "true"
           name_top: RvCoreIbexBranchTargetALU
         }
@@ -8367,6 +8428,7 @@
           desc: Write back stage
           type: bit
           default: "1"
+          local: "false"
           expose: "true"
           name_top: RvCoreIbexWritebackStage
         }
@@ -8375,6 +8437,7 @@
           desc: Instruction cache
           type: bit
           default: "1"
+          local: "false"
           expose: "true"
           name_top: RvCoreIbexICache
         }
@@ -8383,6 +8446,7 @@
           desc: Instruction cache ECC
           type: bit
           default: "1"
+          local: "false"
           expose: "true"
           name_top: RvCoreIbexICacheECC
         }
@@ -8391,6 +8455,7 @@
           desc: Scramble instruction cach
           type: bit
           default: "1"
+          local: "false"
           expose: "true"
           name_top: RvCoreIbexICacheScramble
         }
@@ -8399,6 +8464,7 @@
           desc: Branch predictor
           type: bit
           default: "0"
+          local: "false"
           expose: "true"
           name_top: RvCoreIbexBranchPredictor
         }
@@ -8407,6 +8473,7 @@
           desc: Enable degug trigger
           type: bit
           default: "1"
+          local: "false"
           expose: "true"
           name_top: RvCoreIbexDbgTriggerEn
         }
@@ -8415,6 +8482,7 @@
           desc: Number of debug hardware break
           type: int
           default: "4"
+          local: "false"
           expose: "true"
           name_top: RvCoreIbexDbgHwBreakNum
         }
@@ -8423,6 +8491,7 @@
           desc: "Width of the MHPM Counter "
           type: bit
           default: "1"
+          local: "false"
           expose: "true"
           name_top: RvCoreIbexSecureIbex
         }
@@ -8431,6 +8500,7 @@
           desc: Halt address
           type: int unsigned
           default: tl_main_pkg::ADDR_SPACE_RV_DM__MEM + dm::HaltAddress[31:0]
+          local: "false"
           expose: "true"
           name_top: RvCoreIbexDmHaltAddr
         }
@@ -8439,6 +8509,7 @@
           desc: Exception address
           type: int unsigned
           default: tl_main_pkg::ADDR_SPACE_RV_DM__MEM + dm::ExceptionAddress[31:0]
+          local: "false"
           expose: "true"
           name_top: RvCoreIbexDmExceptionAddr
         }
@@ -8447,6 +8518,7 @@
           desc: Pipe line
           type: bit
           default: "0"
+          local: "false"
           expose: "true"
           name_top: RvCoreIbexPipeLine
         }
diff --git a/hw/top_earlgrey/rtl/autogen/top_earlgrey.sv b/hw/top_earlgrey/rtl/autogen/top_earlgrey.sv
index 8405c618911e7b..dbd5bf433b3042 100644
--- a/hw/top_earlgrey/rtl/autogen/top_earlgrey.sv
+++ b/hw/top_earlgrey/rtl/autogen/top_earlgrey.sv
@@ -224,6 +224,50 @@ module top_earlgrey #(
   // Compile-time random constants
   import top_earlgrey_rnd_cnst_pkg::*;
 
+  // Local Parameters
+  // local parameters for uart0
+  // local parameters for uart1
+  // local parameters for uart2
+  // local parameters for uart3
+  // local parameters for gpio
+  // local parameters for spi_device
+  // local parameters for i2c0
+  // local parameters for i2c1
+  // local parameters for i2c2
+  // local parameters for pattgen
+  // local parameters for rv_timer
+  // local parameters for otp_ctrl
+  // local parameters for lc_ctrl
+  // local parameters for alert_handler
+  // local parameters for spi_host0
+  // local parameters for spi_host1
+  // local parameters for usbdev
+  // local parameters for pwrmgr_aon
+  // local parameters for rstmgr_aon
+  // local parameters for clkmgr_aon
+  // local parameters for sysrst_ctrl_aon
+  // local parameters for adc_ctrl_aon
+  // local parameters for pwm_aon
+  // local parameters for pinmux_aon
+  // local parameters for aon_timer_aon
+  // local parameters for sensor_ctrl_aon
+  // local parameters for sram_ctrl_ret_aon
+  // local parameters for flash_ctrl
+  // local parameters for rv_dm
+  // local parameters for rv_plic
+  // local parameters for aes
+  // local parameters for hmac
+  // local parameters for kmac
+  // local parameters for otbn
+  // local parameters for keymgr
+  // local parameters for csrng
+  // local parameters for entropy_src
+  // local parameters for edn0
+  // local parameters for edn1
+  // local parameters for sram_ctrl_main
+  // local parameters for rom_ctrl
+  // local parameters for rv_core_ibex
+
   // Signals
   logic [56:0] mio_p2d;
   logic [74:0] mio_d2p;
@@ -781,6 +825,7 @@ module top_earlgrey #(
   edn_pkg::edn_rsp_t unused_edn1_edn_rsp7;
 
   // assign partial inter-module tie-off
+
   assign unused_otp_ctrl_sram_otp_key_rsp3 = otp_ctrl_sram_otp_key_rsp[3];
   assign unused_edn1_edn_rsp1 = edn1_edn_rsp[1];
   assign unused_edn1_edn_rsp2 = edn1_edn_rsp[2];
diff --git a/hw/top_earlgrey/templates/toplevel.sv.tpl b/hw/top_earlgrey/templates/toplevel.sv.tpl
index d78088657f66c7..6caaa01ab84b5b 100644
--- a/hw/top_earlgrey/templates/toplevel.sv.tpl
+++ b/hw/top_earlgrey/templates/toplevel.sv.tpl
@@ -5,6 +5,7 @@ ${gencmd}
 <%
 import re
 import topgen.lib as lib
+from reggen.params import Parameter
 from topgen.clocks import Clocks
 from topgen.resets import Resets
 
@@ -22,7 +23,15 @@ num_dio_total = top['pinmux']['io_counts']['dedicated']['inouts'] + \
                 top['pinmux']['io_counts']['dedicated']['inputs'] + \
                 top['pinmux']['io_counts']['dedicated']['outputs']
 
-num_im = sum([x["width"] if "width" in x else 1 for x in top["inter_signal"]["external"]])
+num_im = 0
+for x in top["inter_signal"]["external"]:
+    if "width" in x:
+        if isinstance(x["width"], Parameter):
+            num_im += x["width"].default
+        else:
+            num_im += x["width"]
+    else:
+        num_im += 1
 
 max_sigwidth = max([x["width"] if "width" in x else 1 for x in top["pinmux"]["ios"]])
 max_sigwidth = len("{}".format(max_sigwidth))
@@ -52,7 +61,7 @@ module top_${top["name"]} #(
 <% continue %>
   % endif
   // parameters for ${m['name']}
-  % for p_exp in [p for p in m["param_list"] if p.get("expose") == "true" ]:
+  % for p_exp in [p for p in m["param_list"] if p.get("local") == "false" and p.get("expose") == "true" ]:
 <%
     p_type = p_exp.get('type')
     p_type_word = p_type + ' ' if p_type else ''
@@ -63,7 +72,7 @@ module top_${top["name"]} #(
     params_follow = not loop.last or loop.parent.index < last_modidx_with_params
     comma_char = ',' if params_follow else ''
 %>\
-    % if 12 + len(p_lhs) + 3 + len(p_rhs) + 1 < 100:
+    % if 12 + len(p_lhs) + 3 + len(str(p_rhs)) + 1 < 100:
   parameter ${p_lhs} = ${p_rhs}${comma_char}
     % else:
   parameter ${p_lhs} =
@@ -95,7 +104,11 @@ module top_${top["name"]} #(
 
   // Inter-module Signal External type
   % for sig in top["inter_signal"]["external"]:
+    % if isinstance(sig["width"], Parameter):
+  ${lib.get_direction(sig)} ${lib.im_defname(sig)} [${sig["width"].name_top}-1:0] ${sig["signame"]},
+    % else:
   ${lib.get_direction(sig)} ${lib.im_defname(sig)} ${lib.bitarray(sig["width"],1)} ${sig["signame"]},
+    % endif
   % endfor
 
 % endif
@@ -121,6 +134,29 @@ module top_${top["name"]} #(
   // Compile-time random constants
   import top_${top["name"]}_rnd_cnst_pkg::*;
 
+  // Local Parameters
+% for m in top["module"]:
+  % if not lib.is_inst(m):
+<% continue %>
+  % endif
+  // local parameters for ${m['name']}
+  % for p_exp in [p for p in m["param_list"] if p.get("local") == "true" and p.get("expose") == "true"]:
+<%
+    p_type = p_exp.get('type')
+    p_type_word = p_type + ' ' if p_type else ''
+
+    p_lhs = f'{p_type_word}{p_exp["name_top"]}'
+    p_rhs = p_exp['default']
+%>\
+    % if 13 + len(p_lhs) + 3 + len(str(p_rhs)) + 1 < 100:
+  localparam ${p_lhs} = ${p_rhs};
+    % else:
+  localparam ${p_lhs} =
+      ${p_rhs};
+    % endif
+  % endfor
+% endfor
+
   // Signals
   logic [${num_mio_inputs - 1}:0] mio_p2d;
   logic [${num_mio_outputs - 1}:0] mio_d2p;
@@ -187,7 +223,11 @@ module top_${top["name"]} #(
   // define inter-module signals
 % endif
 % for sig in top["inter_signal"]["definitions"]:
+  % if isinstance(sig["width"], Parameter):
+  ${lib.im_defname(sig)} [${sig["width"].name_top}-1:0] ${sig["signame"]};
+  % else:
   ${lib.im_defname(sig)} ${lib.bitarray(sig["width"],1)} ${sig["signame"]};
+  % endif
 % endfor
 
 ## Mixed connection to port
@@ -213,19 +253,29 @@ module top_${top["name"]} #(
 ## Partial inter-module definition tie-off
   // define partial inter-module tie-off
 % for sig in unused_im_defs:
-  % for idx in range(sig['end_idx'], sig['width']):
+<%
+  width = sig['width'].default if isinstance(sig['width'], Parameter) else sig['width']
+%>\
+  % for idx in range(sig['end_idx'], width):
   ${lib.im_defname(sig)} unused_${sig["signame"]}${idx};
   % endfor
 % endfor
 
   // assign partial inter-module tie-off
+
 % for sig in unused_im_defs:
-  % for idx in range(sig['end_idx'], sig['width']):
+<%
+  width = sig['width'].default if isinstance(sig['width'], Parameter) else sig['width']
+%>\
+  % for idx in range(sig['end_idx'], width):
   assign unused_${sig["signame"]}${idx} = ${sig["signame"]}[${idx}];
   % endfor
 % endfor
 % for sig in undriven_im_defs:
-  % for idx in range(sig['end_idx'], sig['width']):
+<%
+  width = sig['width'].default if isinstance(sig['width'], Parameter) else sig['width']
+%>\
+  % for idx in range(sig['end_idx'], width):
   assign ${sig["signame"]}[${idx}] = ${sig["default"]};
   % endfor
 % endfor
diff --git a/util/reggen/inter_signal.py b/util/reggen/inter_signal.py
index e1cbd19339827b..ae73069f56e045 100644
--- a/util/reggen/inter_signal.py
+++ b/util/reggen/inter_signal.py
@@ -2,10 +2,11 @@
 # Licensed under the Apache License, Version 2.0, see LICENSE for details.
 # SPDX-License-Identifier: Apache-2.0
 
-from typing import Dict, Optional
+from typing import Dict, Optional, Union
 
 from reggen.lib import (check_keys, check_name,
                         check_str, check_optional_str, check_int)
+from reggen.params import Parameter
 
 
 class InterSignal:
@@ -16,9 +17,12 @@ def __init__(self,
                  package: Optional[str],
                  signal_type: str,
                  act: str,
-                 width: int,
+                 width: Union[int, Parameter],
                  default: Optional[str]):
-        assert 0 < width
+        if isinstance(width, Parameter):
+            assert 0 < width.default
+        else:
+            assert 0 < width
         self.name = name
         self.desc = desc
         self.struct = struct
@@ -29,7 +33,7 @@ def __init__(self,
         self.default = default
 
     @staticmethod
-    def from_raw(what: str, raw: object) -> 'InterSignal':
+    def from_raw(params: dict, what: str, raw: object) -> 'InterSignal':
         rd = check_keys(raw, what,
                         ['name', 'struct', 'type', 'act'],
                         ['desc', 'package', 'width', 'default'])
@@ -52,9 +56,21 @@ def from_raw(what: str, raw: object) -> 'InterSignal':
 
         signal_type = check_name(rd['type'], 'type field of ' + what)
         act = check_name(rd['act'], 'act field of ' + what)
-        width = check_int(rd.get('width', 1), 'width field of ' + what)
-        if width <= 0:
-            raise ValueError('width field of {} is not positive.'.format(what))
+
+        try:
+            width = check_int(rd.get('width', 1), 'width field of ' + what)
+        except ValueError:
+            # Value error raised since it is not an int, lets try to find out if it is a Parameter
+            width = params.get(rd.get('width'))
+            width.default = check_int(width.default, 'width field of ' + what)
+            if width.default <= 0:
+                raise ValueError('width field of {} is not positive.'.format(what))
+            # Parameter must be exposed to create a top-level (local) param
+            if not width.expose:
+                raise ValueError('width field of {} is not exposed.'.format(what))
+        else:
+            if width <= 0:
+                raise ValueError('width field of {} is not positive.'.format(what))
 
         default = check_optional_str(rd.get('default'),
                                      'default field of ' + what)
diff --git a/util/reggen/ip_block.py b/util/reggen/ip_block.py
index f468b84770289e..fce877b0b78302 100644
--- a/util/reggen/ip_block.py
+++ b/util/reggen/ip_block.py
@@ -339,6 +339,7 @@ def from_raw(param_defaults: List[Tuple[str, str]],
                                      'inter_signal_list field')
         inter_signals = [
             InterSignal.from_raw(
+                params,
                 'entry {} of the inter_signal_list field'.format(idx + 1),
                 entry) for idx, entry in enumerate(r_inter_signals)
         ]
diff --git a/util/reggen/params.py b/util/reggen/params.py
index 673edf8b0810a6..f141083d02f5d6 100644
--- a/util/reggen/params.py
+++ b/util/reggen/params.py
@@ -78,14 +78,17 @@ def __init__(self,
                  desc: Optional[str],
                  param_type: str,
                  default: str,
+                 local: bool,
                  expose: bool):
         super().__init__(name, desc, param_type)
         self.default = default
+        self.local = local
         self.expose = expose
 
     def as_dict(self) -> Dict[str, object]:
         rd = super().as_dict()
         rd['default'] = self.default
+        rd['local'] = 'true' if self.local else 'false'
         rd['expose'] = 'true' if self.expose else 'false'
         return rd
 
@@ -256,14 +259,12 @@ def _parse_parameter(where: str, raw: object) -> BaseParam:
                       'default field of {}, (an integer parameter)'
                       .format(name))
 
-    if local:
-        if expose:
-            raise ValueError('At {}, the localparam {} cannot be exposed to '
-                             'the top-level.'
-                             .format(where, name))
-        return LocalParam(name, desc, param_type, value=default)
+    if local and expose:
+        return Parameter(name, desc, param_type, default, local, expose)
+    elif local:
+        return LocalParam(name, desc, param_type, default)
     else:
-        return Parameter(name, desc, param_type, default, expose)
+        return Parameter(name, desc, param_type, default, local, expose)
 
 
 # Note: With a modern enough Python, we'd like this to derive from
@@ -378,6 +379,11 @@ def from_raw(where: str, raw: object) -> 'ReggenParams':
     def get_localparams(self) -> List[LocalParam]:
         ret = []
         for param in self.by_name.values():
+            # Emit local params at reg_pkg level for full local params and local params that
+            # are exposed to the top
             if isinstance(param, LocalParam):
                 ret.append(param)
+            elif isinstance(param, Parameter) and param.local:
+                ret.append(param)
+
         return ret
diff --git a/util/topgen.py b/util/topgen.py
index b1688d160d0c88..3b258169e5576c 100755
--- a/util/topgen.py
+++ b/util/topgen.py
@@ -151,6 +151,7 @@ def generate_xbars(top: Dict[str, object], out_path: Path) -> None:
                 "inter_signal_list field")
             obj["inter_signal_list"] = [
                 InterSignal.from_raw(
+                    {},
                     "entry {} of the inter_signal_list field".format(idx + 1),
                     entry) for idx, entry in enumerate(r_inter_signal_list)
             ]
@@ -1134,7 +1135,7 @@ def main():
 """.format(top_name=top_name, seed=completecfg["rnd_cnst_seed"])
 
     genhjson_path.write_text(genhdr + gencmd +
-                             hjson.dumps(completecfg, for_json=True) + '\n')
+                             hjson.dumps(completecfg, for_json=True, default=vars) + '\n')
 
     # Generate Rust toplevel definitions
     if not args.no_rust:
diff --git a/util/topgen/intermodule.py b/util/topgen/intermodule.py
index 7b2938d751f101..2977a43c853680 100644
--- a/util/topgen/intermodule.py
+++ b/util/topgen/intermodule.py
@@ -10,6 +10,7 @@
 
 from reggen.ip_block import IpBlock
 from reggen.inter_signal import InterSignal
+from reggen.params import Parameter
 from reggen.validate import check_int
 from topgen import lib
 
@@ -644,13 +645,18 @@ def check_intermodule_field(sig: OrderedDict,
     width = 1
     if "width" not in sig:
         sig["width"] = 1
+    elif isinstance(sig["width"], Parameter):
+        width, err = check_int(sig["width"].default, sig["name"])
+        if err:
+            log.error(f"{prefix} Inter-module {sig["inst_name"]}.{sig["name"]} 'width' "
+                      "should be int type.")
+            error += 1
     elif not isinstance(sig["width"], int):
         width, err = check_int(sig["width"], sig["name"])
         if err:
-            log.error("{prefix} Inter-module {inst}.{sig} 'width' "
-                      "should be int type.".format(prefix=prefix,
-                                                   inst=sig["inst_name"],
-                                                   sig=sig["name"]))
+            log.error(f"{prefix} Inter-module {sig["inst_name"]}.{sig["name"]} 'width' "
+                      "should be int type.")
+
             error += 1
         else:
             # convert to int value
@@ -821,20 +827,26 @@ def check_intermodule(topcfg: Dict, prefix: str) -> int:
 
         # Determine if broadcast or one-to-N
         log.debug("Handling inter-sig {} {}".format(req_struct['name'], total_width))
+
+        if isinstance(req_struct["width"], Parameter):
+            width = int(req_struct["width"].default)
+        else:
+            width = req_struct["width"]
+
         req_struct["end_idx"] = -1
-        if req_struct["width"] > 1 or len(rsps) != 1:
+        if width > 1 or len(rsps) != 1:
             # If req width is same to the every width of rsps ==> broadcast
-            if len(rsps) * [req_struct["width"]] == widths:
+            if len(rsps) * [width] == widths:
                 log.debug("broadcast type")
                 req_struct["top_type"] = "broadcast"
 
             # If req width is same as total width of rsps ==> one-to-N
-            elif req_struct["width"] == total_width:
+            elif width == total_width:
                 log.debug("one-to-N type")
                 req_struct["top_type"] = "one-to-N"
 
             # one-to-N connection is not fully populated
-            elif req_struct["width"] > total_width:
+            elif width > total_width:
                 log.debug("partial one-to-N type")
                 req_struct["top_type"] = "partial-one-to-N"
                 req_struct["end_idx"] = len(rsps)
@@ -950,8 +962,13 @@ def im_netname(sig: OrderedDict,
             # custom default has been specified
             if obj["default"]:
                 return obj["default"]
-            return "{package}::{struct}_DEFAULT".format(
-                package=obj["package"], struct=obj["struct"].upper())
+            if isinstance(sig["width"], Parameter):
+                return "{{{param}{{{package}::{struct}_DEFAULT}}}}".format(
+                    param=sig["width"].name_top, package=obj["package"],
+                    struct=obj["struct"].upper())
+            else:
+                return "{package}::{struct}_DEFAULT".format(
+                    package=obj["package"], struct=obj["struct"].upper())
 
         return ""
 
diff --git a/util/topgen/merge.py b/util/topgen/merge.py
index 61ad7d6db633c3..1b06ae79745cd2 100644
--- a/util/topgen/merge.py
+++ b/util/topgen/merge.py
@@ -166,6 +166,14 @@ def elaborate_instance(instance, block: IpBlock):
     # to convert and copy them here.
     instance["inter_signal_list"] = [s.as_dict() for s in block.inter_signals]
 
+    # If we have width-parametrized intersignal, we need to update the intersignal param name
+    # the the instance mangled param name
+    for s in instance["inter_signal_list"]:
+        if isinstance(s['width'], Parameter):
+            for p in instance["param_list"]:
+                if p['name'] == s['width'].name:
+                    s['width'].name_top = p['name_top']
+
     # An instance must either have a 'base_addr' address or a 'base_addrs'
     # address, but can't have both.
     base_addrs = instance.get('base_addrs')