diff --git a/src/dma/rtl/taxi_axi_cdma.sv b/src/dma/rtl/taxi_axi_cdma.sv
index d940b41..449206b 100644
--- a/src/dma/rtl/taxi_axi_cdma.sv
+++ b/src/dma/rtl/taxi_axi_cdma.sv
@@ -80,13 +80,14 @@ if (AXI_MAX_BURST_LEN_INT < 1 || AXI_MAX_BURST_LEN_INT > 256)
 if (desc_req.SRC_ADDR_W < AXI_ADDR_W || desc_req.DST_ADDR_W < AXI_ADDR_W)
     $fatal(0, "Error: Descriptor address width is not sufficient (instance %m)");
 
-localparam logic [1:0]
+typedef enum logic [1:0] {
     AXI_RESP_OKAY = 2'b00,
     AXI_RESP_EXOKAY = 2'b01,
     AXI_RESP_SLVERR = 2'b10,
-    AXI_RESP_DECERR = 2'b11;
+    AXI_RESP_DECERR = 2'b11
+} axi_resp_t;
 
-localparam logic [3:0]
+typedef enum logic [3:0] {
     DMA_ERROR_NONE = 4'd0,
     DMA_ERROR_TIMEOUT = 4'd1,
     DMA_ERROR_PARITY = 4'd2,
@@ -97,20 +98,23 @@ localparam logic [3:0]
     DMA_ERROR_PCIE_FLR = 4'd8,
     DMA_ERROR_PCIE_CPL_POISONED = 4'd9,
     DMA_ERROR_PCIE_CPL_STATUS_UR = 4'd10,
-    DMA_ERROR_PCIE_CPL_STATUS_CA = 4'd11;
+    DMA_ERROR_PCIE_CPL_STATUS_CA = 4'd11
+} dma_error_t;
 
-localparam logic [1:0]
-    READ_STATE_IDLE = 2'd0,
-    READ_STATE_START = 2'd1,
-    READ_STATE_REQ = 2'd2;
+typedef enum logic [1:0] {
+    READ_STATE_IDLE,
+    READ_STATE_START,
+    READ_STATE_REQ
+} read_state_t;
 
-logic [1:0] read_state_reg = READ_STATE_IDLE, read_state_next;
+read_state_t read_state_reg = READ_STATE_IDLE, read_state_next;
 
-localparam logic [0:0]
-    AXI_STATE_IDLE = 1'd0,
-    AXI_STATE_WRITE = 1'd1;
+typedef enum logic [0:0] {
+    AXI_STATE_IDLE,
+    AXI_STATE_WRITE
+} axi_state_t;
 
-logic [0:0] axi_state_reg = AXI_STATE_IDLE, axi_state_next;
+axi_state_t axi_state_reg = AXI_STATE_IDLE, axi_state_next;
 
 // datapath control signals
 logic transfer_in_save;
diff --git a/src/dma/rtl/taxi_axi_dma_rd.sv b/src/dma/rtl/taxi_axi_dma_rd.sv
index 51fa293..b51b2eb 100644
--- a/src/dma/rtl/taxi_axi_dma_rd.sv
+++ b/src/dma/rtl/taxi_axi_dma_rd.sv
@@ -107,13 +107,14 @@ if (AXI_MAX_BURST_LEN < 1 || AXI_MAX_BURST_LEN > 256)
 if (rd_desc_req.SRC_ADDR_W < AXI_ADDR_W)
     $fatal(0, "Error: Descriptor address width is not sufficient (instance %m)");
 
-localparam logic [1:0]
+typedef enum logic [1:0] {
     AXI_RESP_OKAY = 2'b00,
     AXI_RESP_EXOKAY = 2'b01,
     AXI_RESP_SLVERR = 2'b10,
-    AXI_RESP_DECERR = 2'b11;
+    AXI_RESP_DECERR = 2'b11
+} axi_resp_t;
 
-localparam logic [3:0]
+typedef enum logic [3:0] {
     DMA_ERROR_NONE = 4'd0,
     DMA_ERROR_TIMEOUT = 4'd1,
     DMA_ERROR_PARITY = 4'd2,
@@ -124,19 +125,22 @@ localparam logic [3:0]
     DMA_ERROR_PCIE_FLR = 4'd8,
     DMA_ERROR_PCIE_CPL_POISONED = 4'd9,
     DMA_ERROR_PCIE_CPL_STATUS_UR = 4'd10,
-    DMA_ERROR_PCIE_CPL_STATUS_CA = 4'd11;
+    DMA_ERROR_PCIE_CPL_STATUS_CA = 4'd11
+} dma_error_t;
 
-localparam logic [0:0]
-    AXI_STATE_IDLE = 1'd0,
-    AXI_STATE_START = 1'd1;
+typedef enum logic [0:0] {
+    AXI_STATE_IDLE,
+    AXI_STATE_START
+} axi_state_t;
 
-logic [0:0] axi_state_reg = AXI_STATE_IDLE, axi_state_next;
+axi_state_t axi_state_reg = AXI_STATE_IDLE, axi_state_next;
 
-localparam logic [0:0]
-    AXIS_STATE_IDLE = 1'd0,
-    AXIS_STATE_READ = 1'd1;
+typedef enum logic [0:0] {
+    AXIS_STATE_IDLE,
+    AXIS_STATE_READ
+} axis_state_t;
 
-logic [0:0] axis_state_reg = AXIS_STATE_IDLE, axis_state_next;
+axis_state_t axis_state_reg = AXIS_STATE_IDLE, axis_state_next;
 
 // datapath control signals
 logic transfer_in_save;
diff --git a/src/dma/rtl/taxi_axi_dma_wr.sv b/src/dma/rtl/taxi_axi_dma_wr.sv
index fea34f2..57bb2a7 100644
--- a/src/dma/rtl/taxi_axi_dma_wr.sv
+++ b/src/dma/rtl/taxi_axi_dma_wr.sv
@@ -109,13 +109,14 @@ if (AXI_MAX_BURST_LEN < 1 || AXI_MAX_BURST_LEN > 256)
 if (wr_desc_req.DST_ADDR_W < AXI_ADDR_W)
     $fatal(0, "Error: Descriptor address width is not sufficient (instance %m)");
 
-localparam logic [1:0]
+typedef enum logic [1:0] {
     AXI_RESP_OKAY = 2'b00,
     AXI_RESP_EXOKAY = 2'b01,
     AXI_RESP_SLVERR = 2'b10,
-    AXI_RESP_DECERR = 2'b11;
+    AXI_RESP_DECERR = 2'b11
+} axi_resp_t;
 
-localparam logic [3:0]
+typedef enum logic [3:0] {
     DMA_ERROR_NONE = 4'd0,
     DMA_ERROR_TIMEOUT = 4'd1,
     DMA_ERROR_PARITY = 4'd2,
@@ -126,16 +127,18 @@ localparam logic [3:0]
     DMA_ERROR_PCIE_FLR = 4'd8,
     DMA_ERROR_PCIE_CPL_POISONED = 4'd9,
     DMA_ERROR_PCIE_CPL_STATUS_UR = 4'd10,
-    DMA_ERROR_PCIE_CPL_STATUS_CA = 4'd11;
+    DMA_ERROR_PCIE_CPL_STATUS_CA = 4'd11
+} dma_error_t;
 
-localparam logic [2:0]
-    STATE_IDLE = 3'd0,
-    STATE_START = 3'd1,
-    STATE_WRITE = 3'd2,
-    STATE_FINISH_BURST = 3'd3,
-    STATE_DROP_DATA = 3'd4;
+typedef enum logic [2:0] {
+    STATE_IDLE,
+    STATE_START,
+    STATE_WRITE,
+    STATE_FINISH_BURST,
+    STATE_DROP_DATA
+} state_t;
 
-logic [2:0] state_reg = STATE_IDLE, state_next;
+state_t state_reg = STATE_IDLE, state_next;
 
 // datapath control signals
 logic transfer_in_save;
diff --git a/src/dma/rtl/taxi_dma_client_axis_sink.sv b/src/dma/rtl/taxi_dma_client_axis_sink.sv
index 7af0b07..e7579ef 100644
--- a/src/dma/rtl/taxi_dma_client_axis_sink.sv
+++ b/src/dma/rtl/taxi_dma_client_axis_sink.sv
@@ -110,12 +110,13 @@ if (AXIS_DATA_W*2**$clog2(PART_COUNT) != RAM_SEGS*RAM_SEG_DATA_W)
 if (desc_req.DST_ADDR_W < RAM_ADDR_W)
     $fatal(0, "Error: Descriptor address width is not sufficient (instance %m)");
 
-localparam logic [1:0]
-    STATE_IDLE = 2'd0,
-    STATE_WRITE = 2'd1,
-    STATE_DROP_DATA = 2'd2;
+typedef enum logic [1:0] {
+    STATE_IDLE,
+    STATE_WRITE,
+    STATE_DROP_DATA
+} state_t;
 
-logic [1:0] state_reg = STATE_IDLE, state_next;
+state_t state_reg = STATE_IDLE, state_next;
 
 logic [OFFSET_W:0] cycle_size;
 
diff --git a/src/dma/rtl/taxi_dma_client_axis_source.sv b/src/dma/rtl/taxi_dma_client_axis_source.sv
index 06f845d..4921919 100644
--- a/src/dma/rtl/taxi_dma_client_axis_source.sv
+++ b/src/dma/rtl/taxi_dma_client_axis_source.sv
@@ -109,17 +109,19 @@ if (AXIS_DATA_W*2**$clog2(PART_COUNT) != RAM_SEGS*RAM_SEG_DATA_W)
 if (desc_req.SRC_ADDR_W < RAM_ADDR_W)
     $fatal(0, "Error: Descriptor address width is not sufficient (instance %m)");
 
-localparam logic [0:0]
-    READ_STATE_IDLE = 1'd0,
-    READ_STATE_READ = 1'd1;
+typedef enum logic [0:0] {
+    READ_STATE_IDLE,
+    READ_STATE_READ
+} read_state_t;
 
-logic [0:0] read_state_reg = READ_STATE_IDLE, read_state_next;
+read_state_t read_state_reg = READ_STATE_IDLE, read_state_next;
 
-localparam logic [0:0]
-    AXIS_STATE_IDLE = 1'd0,
-    AXIS_STATE_READ = 1'd1;
+typedef enum logic [0:0] {
+    AXIS_STATE_IDLE,
+    AXIS_STATE_READ
+} axis_state_t;
 
-logic [0:0] axis_state_reg = AXIS_STATE_IDLE, axis_state_next;
+axis_state_t axis_state_reg = AXIS_STATE_IDLE, axis_state_next;
 
 // datapath control signals
 logic axis_cmd_ready;
diff --git a/src/dma/rtl/taxi_dma_if_axi_rd.sv b/src/dma/rtl/taxi_dma_if_axi_rd.sv
index 4f2d15f..8c0a26c 100644
--- a/src/dma/rtl/taxi_dma_if_axi_rd.sv
+++ b/src/dma/rtl/taxi_dma_if_axi_rd.sv
@@ -142,13 +142,14 @@ if (OP_TBL_SIZE > 2**AXI_ID_W)
 if (rd_desc_req.SRC_ADDR_W < AXI_ADDR_W || rd_desc_req.DST_ADDR_W < RAM_ADDR_W)
     $fatal(0, "Error: Descriptor address width is not sufficient (instance %m)");
 
-localparam logic [1:0]
+typedef enum logic [1:0] {
     AXI_RESP_OKAY = 2'b00,
     AXI_RESP_EXOKAY = 2'b01,
     AXI_RESP_SLVERR = 2'b10,
-    AXI_RESP_DECERR = 2'b11;
+    AXI_RESP_DECERR = 2'b11
+} axi_resp_t;
 
-localparam logic [3:0]
+typedef enum logic [3:0] {
     DMA_ERROR_NONE = 4'd0,
     DMA_ERROR_TIMEOUT = 4'd1,
     DMA_ERROR_PARITY = 4'd2,
@@ -159,19 +160,22 @@ localparam logic [3:0]
     DMA_ERROR_PCIE_FLR = 4'd8,
     DMA_ERROR_PCIE_CPL_POISONED = 4'd9,
     DMA_ERROR_PCIE_CPL_STATUS_UR = 4'd10,
-    DMA_ERROR_PCIE_CPL_STATUS_CA = 4'd11;
+    DMA_ERROR_PCIE_CPL_STATUS_CA = 4'd11
+} dma_error_t;
 
-localparam logic [0:0]
-    REQ_STATE_IDLE = 1'd0,
-    REQ_STATE_START = 1'd1;
+typedef enum logic [0:0] {
+    REQ_STATE_IDLE,
+    REQ_STATE_START
+} req_state_t;
 
-logic [0:0] req_state_reg = REQ_STATE_IDLE, req_state_next;
+req_state_t req_state_reg = REQ_STATE_IDLE, req_state_next;
 
-localparam logic [0:0]
-    AXI_STATE_IDLE = 1'd0,
-    AXI_STATE_WRITE = 1'd1;
+typedef enum logic [0:0] {
+    AXI_STATE_IDLE,
+    AXI_STATE_WRITE
+} axi_state_t;
 
-logic [0:0] axi_state_reg = AXI_STATE_IDLE, axi_state_next;
+axi_state_t axi_state_reg = AXI_STATE_IDLE, axi_state_next;
 
 logic [AXI_ADDR_W-1:0] req_axi_addr_reg = '0, req_axi_addr_next;
 logic [RAM_SEL_W-1:0] req_ram_sel_reg = '0, req_ram_sel_next;
diff --git a/src/dma/rtl/taxi_dma_if_axi_wr.sv b/src/dma/rtl/taxi_dma_if_axi_wr.sv
index 71c46ac..9fe3cf7 100644
--- a/src/dma/rtl/taxi_dma_if_axi_wr.sv
+++ b/src/dma/rtl/taxi_dma_if_axi_wr.sv
@@ -146,13 +146,14 @@ if (IMM_EN && IMM_W > AXI_DATA_W)
 if (wr_desc_req.SRC_ADDR_W < RAM_ADDR_W || wr_desc_req.DST_ADDR_W < AXI_ADDR_W)
     $fatal(0, "Error: Descriptor address width is not sufficient (instance %m)");
 
-localparam logic [1:0]
+typedef enum logic [1:0] {
     AXI_RESP_OKAY = 2'b00,
     AXI_RESP_EXOKAY = 2'b01,
     AXI_RESP_SLVERR = 2'b10,
-    AXI_RESP_DECERR = 2'b11;
+    AXI_RESP_DECERR = 2'b11
+} axi_resp_t;
 
-localparam logic [3:0]
+typedef enum logic [3:0] {
     DMA_ERROR_NONE = 4'd0,
     DMA_ERROR_TIMEOUT = 4'd1,
     DMA_ERROR_PARITY = 4'd2,
@@ -163,25 +164,29 @@ localparam logic [3:0]
     DMA_ERROR_PCIE_FLR = 4'd8,
     DMA_ERROR_PCIE_CPL_POISONED = 4'd9,
     DMA_ERROR_PCIE_CPL_STATUS_UR = 4'd10,
-    DMA_ERROR_PCIE_CPL_STATUS_CA = 4'd11;
+    DMA_ERROR_PCIE_CPL_STATUS_CA = 4'd11
+} dma_error_t;
 
-localparam logic [0:0]
-    REQ_STATE_IDLE = 1'd0,
-    REQ_STATE_START = 1'd1;
+typedef enum logic [0:0] {
+    REQ_STATE_IDLE,
+    REQ_STATE_START
+} req_state_t;
 
-logic [0:0] req_state_reg = REQ_STATE_IDLE, req_state_next;
+req_state_t req_state_reg = REQ_STATE_IDLE, req_state_next;
 
-localparam logic [0:0]
-    READ_STATE_IDLE = 1'd0,
-    READ_STATE_READ = 1'd1;
+typedef enum logic [0:0] {
+    READ_STATE_IDLE,
+    READ_STATE_READ
+} read_state_t;
 
-logic [0:0] read_state_reg = READ_STATE_IDLE, read_state_next;
+read_state_t read_state_reg = READ_STATE_IDLE, read_state_next;
 
-localparam logic [0:0]
-    AXI_STATE_IDLE = 1'd0,
-    AXI_STATE_TRANSFER = 1'd1;
+typedef enum logic [0:0] {
+    AXI_STATE_IDLE,
+    AXI_STATE_TRANSFER
+} axi_state_t;
 
-logic [0:0] axi_state_reg = AXI_STATE_IDLE, axi_state_next;
+axi_state_t axi_state_reg = AXI_STATE_IDLE, axi_state_next;
 
 // datapath control signals
 logic mask_fifo_we;
diff --git a/src/dma/rtl/taxi_dma_if_pcie_us_rd.sv b/src/dma/rtl/taxi_dma_if_pcie_us_rd.sv
index 9ed3c22..2003e77 100644
--- a/src/dma/rtl/taxi_dma_if_pcie_us_rd.sv
+++ b/src/dma/rtl/taxi_dma_if_pcie_us_rd.sv
@@ -213,7 +213,7 @@ if (PCIE_TAG_CNT < 1 || PCIE_TAG_CNT > 256)
 if (rd_desc_req.SRC_ADDR_W < PCIE_ADDR_W || rd_desc_req.DST_ADDR_W < RAM_ADDR_W)
     $fatal(0, "Error: Descriptor address width is not sufficient (instance %m)");
 
-localparam logic [3:0]
+typedef enum logic [3:0] {
     REQ_MEM_READ = 4'b0000,
     REQ_MEM_WRITE = 4'b0001,
     REQ_IO_READ = 4'b0010,
@@ -221,22 +221,24 @@ localparam logic [3:0]
     REQ_MEM_FETCH_ADD = 4'b0100,
     REQ_MEM_SWAP = 4'b0101,
     REQ_MEM_CAS = 4'b0110,
-    REQ_MEM_RD_LOCKED = 4'b0111,
-    REQ_CFG_RD_0 = 4'b1000,
-    REQ_CFG_RD_1 = 4'b1001,
+    REQ_MEM_READ_LOCKED = 4'b0111,
+    REQ_CFG_READ_0 = 4'b1000,
+    REQ_CFG_READ_1 = 4'b1001,
     REQ_CFG_WRITE_0 = 4'b1010,
     REQ_CFG_WRITE_1 = 4'b1011,
     REQ_MSG = 4'b1100,
     REQ_MSG_VENDOR = 4'b1101,
-    REQ_MSG_ATS = 4'b1110;
+    REQ_MSG_ATS = 4'b1110
+} req_type_t;
 
-localparam logic [2:0]
+typedef enum logic [2:0] {
     CPL_STATUS_SC  = 3'b000, // successful completion
     CPL_STATUS_UR  = 3'b001, // unsupported request
     CPL_STATUS_CRS = 3'b010, // configuration request retry status
-    CPL_STATUS_CA  = 3'b100; // completer abort
+    CPL_STATUS_CA  = 3'b100  // completer abort
+} cpl_status_t;
 
-localparam logic [3:0]
+typedef enum logic [3:0] {
     RC_ERR_NORMAL_TERM = 4'b0000,
     RC_ERR_POISONED = 4'b0001,
     RC_ERR_BAD_STATUS = 4'b0010,
@@ -245,9 +247,10 @@ localparam logic [3:0]
     RC_ERR_INVALID_ADDR = 4'b0101,
     RC_ERR_INVALID_TAG = 4'b0110,
     RC_ERR_TIMEOUT = 4'b1001,
-    RC_ERR_FLR = 4'b1000;
+    RC_ERR_FLR = 4'b1000
+} rc_err_t;
 
-localparam logic [3:0]
+typedef enum logic [3:0] {
     DMA_ERR_NONE = 4'd0,
     DMA_ERR_TIMEOUT = 4'd1,
     DMA_ERR_PARITY = 4'd2,
@@ -258,22 +261,25 @@ localparam logic [3:0]
     DMA_ERR_PCIE_FLR = 4'd8,
     DMA_ERR_PCIE_CPL_POISONED = 4'd9,
     DMA_ERR_PCIE_CPL_STATUS_UR = 4'd10,
-    DMA_ERR_PCIE_CPL_STATUS_CA = 4'd11;
+    DMA_ERR_PCIE_CPL_STATUS_CA = 4'd11
+} dma_err_t;
 
-localparam logic [1:0]
-    REQ_STATE_IDLE = 2'd0,
-    REQ_STATE_START = 2'd1,
-    REQ_STATE_HEADER = 2'd2;
+typedef enum logic [1:0] {
+    REQ_STATE_IDLE,
+    REQ_STATE_START,
+    REQ_STATE_HEADER
+} req_state_t;
 
-logic [1:0] req_state_reg = REQ_STATE_IDLE, req_state_next;
+req_state_t req_state_reg = REQ_STATE_IDLE, req_state_next;
 
-localparam logic [1:0]
+typedef enum logic [1:0] {
     TLP_STATE_IDLE = 2'd0,
     TLP_STATE_HEADER = 2'd1,
     TLP_STATE_WRITE = 2'd2,
-    TLP_STATE_WAIT_END = 2'd3;
+    TLP_STATE_WAIT_END = 2'd3
+} tlp_state_t;
 
-logic [1:0] tlp_state_reg = TLP_STATE_IDLE, tlp_state_next;
+tlp_state_t tlp_state_reg = TLP_STATE_IDLE, tlp_state_next;
 
 // datapath control signals
 logic last_cycle;
diff --git a/src/dma/rtl/taxi_dma_if_pcie_us_wr.sv b/src/dma/rtl/taxi_dma_if_pcie_us_wr.sv
index 70b88b7..07ebc9a 100644
--- a/src/dma/rtl/taxi_dma_if_pcie_us_wr.sv
+++ b/src/dma/rtl/taxi_dma_if_pcie_us_wr.sv
@@ -182,7 +182,7 @@ if (2**$clog2(RAM_BYTE_LANES) != RAM_BYTE_LANES)
 if (wr_desc_req.SRC_ADDR_W < RAM_ADDR_W || wr_desc_req.DST_ADDR_W < PCIE_ADDR_W)
     $fatal(0, "Error: Descriptor address width is not sufficient (instance %m)");
 
-localparam logic [3:0]
+typedef enum logic [3:0] {
     REQ_MEM_READ = 4'b0000,
     REQ_MEM_WRITE = 4'b0001,
     REQ_IO_READ = 4'b0010,
@@ -193,44 +193,50 @@ localparam logic [3:0]
     REQ_MEM_READ_LOCKED = 4'b0111,
     REQ_CFG_READ_0 = 4'b1000,
     REQ_CFG_READ_1 = 4'b1001,
-    REQ_CFG_WR_0 = 4'b1010,
-    REQ_CFG_WR_1 = 4'b1011,
+    REQ_CFG_WRITE_0 = 4'b1010,
+    REQ_CFG_WRITE_1 = 4'b1011,
     REQ_MSG = 4'b1100,
     REQ_MSG_VENDOR = 4'b1101,
-    REQ_MSG_ATS = 4'b1110;
+    REQ_MSG_ATS = 4'b1110
+} req_type_t;
 
-localparam logic [2:0]
+typedef enum logic [2:0] {
     CPL_STATUS_SC  = 3'b000, // successful completion
     CPL_STATUS_UR  = 3'b001, // unsupported request
     CPL_STATUS_CRS = 3'b010, // configuration request retry status
-    CPL_STATUS_CA  = 3'b100; // completer abort
+    CPL_STATUS_CA  = 3'b100  // completer abort
+} cpl_status_t;
 
-localparam logic [0:0]
-    REQ_STATE_IDLE = 1'd0,
-    REQ_STATE_START = 1'd1;
+typedef enum logic [0:0] {
+    REQ_STATE_IDLE,
+    REQ_STATE_START
+} req_state_t;
 
-logic [0:0] req_state_reg = REQ_STATE_IDLE, req_state_next;
+req_state_t req_state_reg = REQ_STATE_IDLE, req_state_next;
 
-localparam logic [0:0]
-    READ_STATE_IDLE = 1'd0,
-    READ_STATE_READ = 1'd1;
+typedef enum logic [0:0] {
+    READ_STATE_IDLE,
+    READ_STATE_READ
+} read_state_t;
 
-logic [0:0] read_state_reg = READ_STATE_IDLE, read_state_next;
+read_state_t read_state_reg = READ_STATE_IDLE, read_state_next;
 
-localparam logic [1:0]
-    TLP_STATE_IDLE = 2'd0,
-    TLP_STATE_HEADER = 2'd1,
-    TLP_STATE_TRANSFER = 2'd2;
+typedef enum logic [1:0] {
+    TLP_STATE_IDLE,
+    TLP_STATE_HEADER,
+    TLP_STATE_TRANSFER
+} tlp_state_t;
 
-logic [1:0] tlp_state_reg = TLP_STATE_IDLE, tlp_state_next;
+tlp_state_t tlp_state_reg = TLP_STATE_IDLE, tlp_state_next;
 
-localparam logic [1:0]
-    TLP_OUTPUT_STATE_IDLE = 2'd0,
-    TLP_OUTPUT_STATE_HEADER = 2'd1,
-    TLP_OUTPUT_STATE_PAYLOAD = 2'd2,
-    TLP_OUTPUT_STATE_PASSTHROUGH = 2'd3;
+typedef enum logic [1:0] {
+    TLP_OUTPUT_STATE_IDLE,
+    TLP_OUTPUT_STATE_HEADER,
+    TLP_OUTPUT_STATE_PAYLOAD,
+    TLP_OUTPUT_STATE_PASSTHROUGH
+} tlp_output_state_t;
 
-logic [1:0] tlp_output_state_reg = TLP_OUTPUT_STATE_IDLE, tlp_output_state_next;
+tlp_output_state_t tlp_output_state_reg = TLP_OUTPUT_STATE_IDLE, tlp_output_state_next;
 
 // datapath control signals
 logic mask_fifo_we;