diff options
author | Joachim StroĢmbergson <joachim@secworks.se> | 2015-02-01 09:12:26 +0100 |
---|---|---|
committer | Joachim StroĢmbergson <joachim@secworks.se> | 2015-02-01 09:12:26 +0100 |
commit | a67abc2f80d5181d607abb8663d13f6dd8ec1b0b (patch) | |
tree | 3a3b751d65b3dcb6b9d13eff8a2569f4a7508dea /rtl/src/verilog/eim_arbiter.v | |
parent | 5150947e0bfc393b03e49bcb37e1168eb02f5b67 (diff) |
Removed trailing whitespace and ^M.
Diffstat (limited to 'rtl/src/verilog/eim_arbiter.v')
-rw-r--r-- | rtl/src/verilog/eim_arbiter.v | 486 |
1 files changed, 243 insertions, 243 deletions
diff --git a/rtl/src/verilog/eim_arbiter.v b/rtl/src/verilog/eim_arbiter.v index 247ff69..1e39629 100644 --- a/rtl/src/verilog/eim_arbiter.v +++ b/rtl/src/verilog/eim_arbiter.v @@ -1,247 +1,247 @@ -`timescale 1ns / 1ps
-
-module eim_arbiter
- (
+`timescale 1ns / 1ps + +module eim_arbiter + ( eim_bclk, eim_cs0_n, eim_da, eim_lba_n, eim_wr_n, - eim_oe_n, eim_wait_n,
-
- sys_clk,
- sys_addr,
- sys_wren, sys_data_out,
- sys_rden, sys_data_in
- );
-
-
- //
- // Ports
- //
- input wire eim_bclk; // | eim bus
- input wire eim_cs0_n; // |
+ eim_oe_n, eim_wait_n, + + sys_clk, + sys_addr, + sys_wren, sys_data_out, + sys_rden, sys_data_in + ); + + + // + // Ports + // + input wire eim_bclk; // | eim bus + input wire eim_cs0_n; // | inout wire [15: 0] eim_da; // | - input wire eim_lba_n; // |
+ input wire eim_lba_n; // | input wire eim_wr_n; // | - input wire eim_oe_n; // |
- output wire eim_wait_n; // |
-
- input wire sys_clk; // system clock
-
- output wire [13: 0] sys_addr; // | user bus
- output wire sys_wren; // |
- output wire [31: 0] sys_data_out; // |
- output wire sys_rden; // |
- input wire [31: 0] sys_data_in; // |
-
-
- //
- // Data/Address PHY
- //
-
- /* PHY is needed to control bi-directional address/data bus. */
-
- wire [15: 0] da_ro; // value read from pins
- reg [15: 0] da_di; // value drives onto pins
-
- eim_da_phy da_phy
- (
- .buf_io (eim_da), // <-- connect directly top-level port
- .buf_di (da_di),
- .buf_ro (da_ro),
- .buf_t (eim_oe_n) // <-- driven by EIM directly
- );
-
-
- //
- // FSM
- //
- localparam EIM_FSM_STATE_INIT = 5'b0_0_000; // arbiter is idle
-
- localparam EIM_FSM_STATE_WRITE_START = 5'b1_1_000; // got address to write at
- localparam EIM_FSM_STATE_WRITE_LSB = 5'b1_1_001; // got lower 16 bits of data to write
- localparam EIM_FSM_STATE_WRITE_MSB = 5'b1_1_010; // got upper 16 bits of data to write
- localparam EIM_FSM_STATE_WRITE_WAIT = 5'b1_1_100; // request to user-side logic sent
- localparam EIM_FSM_STATE_WRITE_DONE = 5'b1_1_111; // user-side logic acknowledged transaction
-
- localparam EIM_FSM_STATE_READ_START = 5'b1_0_000; // got address to read from
- localparam EIM_FSM_STATE_READ_WAIT = 5'b1_0_100; // request to user-side logic sent
- localparam EIM_FSM_STATE_READ_READY = 5'b1_0_011; // got acknowledge from user logic
- localparam EIM_FSM_STATE_READ_LSB = 5'b1_0_001; // returned lower 16 bits to master
- localparam EIM_FSM_STATE_READ_MSB = 5'b1_0_010; // returned upper 16 bits to master
- localparam EIM_FSM_STATE_READ_DONE = 5'b1_0_111; // transaction complete
-
- reg [ 4: 0] eim_fsm_state = EIM_FSM_STATE_INIT; // fsm state
- reg [13: 0] eim_addr_latch = {14{1'bX}}; // transaction address
- reg [15: 0] eim_write_lsb_latch = {16{1'bX}}; // lower 16 bits of data to write
-
- /* These flags are used to wake up from INIT state. */
- wire eim_write_start_flag = (eim_lba_n == 1'b0) && (eim_wr_n == 1'b0) && (da_ro[1:0] == 2'b00);
- wire eim_read_start_flag = (eim_lba_n == 1'b0) && (eim_wr_n == 1'b1) && (da_ro[1:0] == 2'b00);
-
- /* These are transaction response flag and data from user-side logic. */
- wire eim_user_ack;
- wire [31: 0] eim_user_data;
-
- /* FSM is reset whenever Chip Select is de-asserted. */
-
- //
- // FSM Transition Logic
- //
- always @(posedge eim_bclk or posedge eim_cs0_n) begin
- //
- if (eim_cs0_n == 1'b1) eim_fsm_state <= EIM_FSM_STATE_INIT;
- //
- else begin
- //
- case (eim_fsm_state)
- //
- // INIT -> WRITE, INIT -> READ
- //
- EIM_FSM_STATE_INIT: begin
- if (eim_write_start_flag) eim_fsm_state <= EIM_FSM_STATE_WRITE_START;
- if (eim_read_start_flag) eim_fsm_state <= EIM_FSM_STATE_READ_START;
- end
- //
- // WRITE
- //
- EIM_FSM_STATE_WRITE_START: eim_fsm_state <= EIM_FSM_STATE_WRITE_LSB;
- //
- EIM_FSM_STATE_WRITE_LSB: eim_fsm_state <= EIM_FSM_STATE_WRITE_MSB;
- //
- EIM_FSM_STATE_WRITE_MSB: eim_fsm_state <= EIM_FSM_STATE_WRITE_WAIT;
- //
- EIM_FSM_STATE_WRITE_WAIT:
- if (eim_user_ack) eim_fsm_state <= EIM_FSM_STATE_WRITE_DONE;
- //
- EIM_FSM_STATE_WRITE_DONE: eim_fsm_state <= EIM_FSM_STATE_INIT;
- //
- // READ
- //
- EIM_FSM_STATE_READ_START: eim_fsm_state <= EIM_FSM_STATE_READ_WAIT;
- //
- EIM_FSM_STATE_READ_WAIT:
- if (eim_user_ack) eim_fsm_state <= EIM_FSM_STATE_READ_READY;
- //
- EIM_FSM_STATE_READ_READY: eim_fsm_state <= EIM_FSM_STATE_READ_LSB;
- //
- EIM_FSM_STATE_READ_LSB: eim_fsm_state <= EIM_FSM_STATE_READ_MSB;
- //
- EIM_FSM_STATE_READ_MSB: eim_fsm_state <= EIM_FSM_STATE_READ_DONE;
- //
- EIM_FSM_STATE_READ_DONE: eim_fsm_state <= EIM_FSM_STATE_INIT;
- //
- //
- //
- default: eim_fsm_state <= EIM_FSM_STATE_INIT;
- //
- endcase
- //
- end
- //
- end
-
-
- //
- // Address Latch
- //
- always @(posedge eim_bclk)
- //
- if ((eim_fsm_state == EIM_FSM_STATE_INIT) && (eim_write_start_flag || eim_read_start_flag))
- eim_addr_latch <= da_ro[15:2];
-
-
- //
- // Additional Write Logic
- //
- always @(posedge eim_bclk)
- //
- if (eim_fsm_state == EIM_FSM_STATE_WRITE_START)
- eim_write_lsb_latch <= da_ro;
-
-
- //
- // Additional Read Logic
- //
-
- /* Note that this stuff operates on falling clock edge, because the cpu
- * samples our bi-directional data bus on rising clock edge.
- */
-
- always @(negedge eim_bclk or posedge eim_cs0_n)
- //
- if (eim_cs0_n == 1'b1) da_di <= {16{1'bX}}; // don't care what to drive
- else begin
- //
- if (eim_fsm_state == EIM_FSM_STATE_READ_LSB) da_di <= eim_user_data[15: 0]; // drive lower 16 bits at first...
- if (eim_fsm_state == EIM_FSM_STATE_READ_MSB) da_di <= eim_user_data[31:16]; // ...then drive upper 16 bits
- //
- end
-
-
- //
- // Wait Logic
- //
-
- /* Note that this stuff operates on falling clock edge, because the cpu
- * samples our WAIT_N flag on rising clock edge.
- */
-
- reg eim_wait_reg = 1'b0;
-
- always @(negedge eim_bclk or posedge eim_cs0_n)
- //
- if (eim_cs0_n == 1'b1) eim_wait_reg <= 1'b0; // clear wait
- else begin
- //
- if (eim_fsm_state == EIM_FSM_STATE_WRITE_START) eim_wait_reg <= 1'b1; // start waiting for write to complete
- if (eim_fsm_state == EIM_FSM_STATE_READ_START) eim_wait_reg <= 1'b1; // start waiting for read to complete
- //
- if (eim_fsm_state == EIM_FSM_STATE_WRITE_DONE) eim_wait_reg <= 1'b0; // write transaction done
- if (eim_fsm_state == EIM_FSM_STATE_READ_READY) eim_wait_reg <= 1'b0; // read transaction done
- //
- if (eim_fsm_state == EIM_FSM_STATE_INIT) eim_wait_reg <= 1'b0; // fsm is idle, no need to wait any more
- //
- end
-
- assign eim_wait_n = ~eim_wait_reg;
-
-
- /* These flags are used to generate 1-cycle pulses to trigger CDC transaction.
- * Note that FSM goes from WRITE_LSB to WRITE_MSB and from READ_START to READ_WAIT
- * unconditionally, so these flags will always be active for 1 cycle only, which
- * is exactly what we need.
- */
-
- wire arbiter_write_req_pulse = (eim_fsm_state == EIM_FSM_STATE_WRITE_LSB) ? 1'b1 : 1'b0;
- wire arbiter_read_req_pulse = (eim_fsm_state == EIM_FSM_STATE_READ_START) ? 1'b1 : 1'b0;
-
- //
- // CDC Block
- //
-
- /* This block is used to transfer request data from BCLK clock domain to SYS_CLK clock domain and
- * then transfer acknowledge from SYS_CLK to BCLK clock domain in return. Af first 1+1+14+32 = 48 bits
- * are transfered, these are: write flag, read flag, address, write data. During read transaction
- * some bogus write data is passed, which is not used later anyway. During read requests 32 bits of data
- * are returned, during write requests 32 bits of bogus data are returned, that are never used later.
- */
-
- eim_arbiter_cdc eim_cdc
- (
- .eim_clk (eim_bclk),
-
- .eim_req (arbiter_write_req_pulse | arbiter_read_req_pulse),
- .eim_ack (eim_user_ack),
-
- .eim_din ({arbiter_write_req_pulse, arbiter_read_req_pulse, eim_addr_latch, da_ro, eim_write_lsb_latch}),
- .eim_dout (eim_user_data),
-
- .sys_clk (sys_clk),
- .sys_addr (sys_addr),
- .sys_wren (sys_wren),
- .sys_data_out (sys_data_out),
- .sys_rden (sys_rden),
- .sys_data_in (sys_data_in)
- );
-
-
-endmodule
+ input wire eim_oe_n; // | + output wire eim_wait_n; // | + + input wire sys_clk; // system clock + + output wire [13: 0] sys_addr; // | user bus + output wire sys_wren; // | + output wire [31: 0] sys_data_out; // | + output wire sys_rden; // | + input wire [31: 0] sys_data_in; // | + + + // + // Data/Address PHY + // + + /* PHY is needed to control bi-directional address/data bus. */ + + wire [15: 0] da_ro; // value read from pins + reg [15: 0] da_di; // value drives onto pins + + eim_da_phy da_phy + ( + .buf_io (eim_da), // <-- connect directly top-level port + .buf_di (da_di), + .buf_ro (da_ro), + .buf_t (eim_oe_n) // <-- driven by EIM directly + ); + + + // + // FSM + // + localparam EIM_FSM_STATE_INIT = 5'b0_0_000; // arbiter is idle + + localparam EIM_FSM_STATE_WRITE_START = 5'b1_1_000; // got address to write at + localparam EIM_FSM_STATE_WRITE_LSB = 5'b1_1_001; // got lower 16 bits of data to write + localparam EIM_FSM_STATE_WRITE_MSB = 5'b1_1_010; // got upper 16 bits of data to write + localparam EIM_FSM_STATE_WRITE_WAIT = 5'b1_1_100; // request to user-side logic sent + localparam EIM_FSM_STATE_WRITE_DONE = 5'b1_1_111; // user-side logic acknowledged transaction + + localparam EIM_FSM_STATE_READ_START = 5'b1_0_000; // got address to read from + localparam EIM_FSM_STATE_READ_WAIT = 5'b1_0_100; // request to user-side logic sent + localparam EIM_FSM_STATE_READ_READY = 5'b1_0_011; // got acknowledge from user logic + localparam EIM_FSM_STATE_READ_LSB = 5'b1_0_001; // returned lower 16 bits to master + localparam EIM_FSM_STATE_READ_MSB = 5'b1_0_010; // returned upper 16 bits to master + localparam EIM_FSM_STATE_READ_DONE = 5'b1_0_111; // transaction complete + + reg [ 4: 0] eim_fsm_state = EIM_FSM_STATE_INIT; // fsm state + reg [13: 0] eim_addr_latch = {14{1'bX}}; // transaction address + reg [15: 0] eim_write_lsb_latch = {16{1'bX}}; // lower 16 bits of data to write + + /* These flags are used to wake up from INIT state. */ + wire eim_write_start_flag = (eim_lba_n == 1'b0) && (eim_wr_n == 1'b0) && (da_ro[1:0] == 2'b00); + wire eim_read_start_flag = (eim_lba_n == 1'b0) && (eim_wr_n == 1'b1) && (da_ro[1:0] == 2'b00); + + /* These are transaction response flag and data from user-side logic. */ + wire eim_user_ack; + wire [31: 0] eim_user_data; + + /* FSM is reset whenever Chip Select is de-asserted. */ + + // + // FSM Transition Logic + // + always @(posedge eim_bclk or posedge eim_cs0_n) begin + // + if (eim_cs0_n == 1'b1) eim_fsm_state <= EIM_FSM_STATE_INIT; + // + else begin + // + case (eim_fsm_state) + // + // INIT -> WRITE, INIT -> READ + // + EIM_FSM_STATE_INIT: begin + if (eim_write_start_flag) eim_fsm_state <= EIM_FSM_STATE_WRITE_START; + if (eim_read_start_flag) eim_fsm_state <= EIM_FSM_STATE_READ_START; + end + // + // WRITE + // + EIM_FSM_STATE_WRITE_START: eim_fsm_state <= EIM_FSM_STATE_WRITE_LSB; + // + EIM_FSM_STATE_WRITE_LSB: eim_fsm_state <= EIM_FSM_STATE_WRITE_MSB; + // + EIM_FSM_STATE_WRITE_MSB: eim_fsm_state <= EIM_FSM_STATE_WRITE_WAIT; + // + EIM_FSM_STATE_WRITE_WAIT: + if (eim_user_ack) eim_fsm_state <= EIM_FSM_STATE_WRITE_DONE; + // + EIM_FSM_STATE_WRITE_DONE: eim_fsm_state <= EIM_FSM_STATE_INIT; + // + // READ + // + EIM_FSM_STATE_READ_START: eim_fsm_state <= EIM_FSM_STATE_READ_WAIT; + // + EIM_FSM_STATE_READ_WAIT: + if (eim_user_ack) eim_fsm_state <= EIM_FSM_STATE_READ_READY; + // + EIM_FSM_STATE_READ_READY: eim_fsm_state <= EIM_FSM_STATE_READ_LSB; + // + EIM_FSM_STATE_READ_LSB: eim_fsm_state <= EIM_FSM_STATE_READ_MSB; + // + EIM_FSM_STATE_READ_MSB: eim_fsm_state <= EIM_FSM_STATE_READ_DONE; + // + EIM_FSM_STATE_READ_DONE: eim_fsm_state <= EIM_FSM_STATE_INIT; + // + // + // + default: eim_fsm_state <= EIM_FSM_STATE_INIT; + // + endcase + // + end + // + end + + + // + // Address Latch + // + always @(posedge eim_bclk) + // + if ((eim_fsm_state == EIM_FSM_STATE_INIT) && (eim_write_start_flag || eim_read_start_flag)) + eim_addr_latch <= da_ro[15:2]; + + + // + // Additional Write Logic + // + always @(posedge eim_bclk) + // + if (eim_fsm_state == EIM_FSM_STATE_WRITE_START) + eim_write_lsb_latch <= da_ro; + + + // + // Additional Read Logic + // + + /* Note that this stuff operates on falling clock edge, because the cpu + * samples our bi-directional data bus on rising clock edge. + */ + + always @(negedge eim_bclk or posedge eim_cs0_n) + // + if (eim_cs0_n == 1'b1) da_di <= {16{1'bX}}; // don't care what to drive + else begin + // + if (eim_fsm_state == EIM_FSM_STATE_READ_LSB) da_di <= eim_user_data[15: 0]; // drive lower 16 bits at first... + if (eim_fsm_state == EIM_FSM_STATE_READ_MSB) da_di <= eim_user_data[31:16]; // ...then drive upper 16 bits + // + end + + + // + // Wait Logic + // + + /* Note that this stuff operates on falling clock edge, because the cpu + * samples our WAIT_N flag on rising clock edge. + */ + + reg eim_wait_reg = 1'b0; + + always @(negedge eim_bclk or posedge eim_cs0_n) + // + if (eim_cs0_n == 1'b1) eim_wait_reg <= 1'b0; // clear wait + else begin + // + if (eim_fsm_state == EIM_FSM_STATE_WRITE_START) eim_wait_reg <= 1'b1; // start waiting for write to complete + if (eim_fsm_state == EIM_FSM_STATE_READ_START) eim_wait_reg <= 1'b1; // start waiting for read to complete + // + if (eim_fsm_state == EIM_FSM_STATE_WRITE_DONE) eim_wait_reg <= 1'b0; // write transaction done + if (eim_fsm_state == EIM_FSM_STATE_READ_READY) eim_wait_reg <= 1'b0; // read transaction done + // + if (eim_fsm_state == EIM_FSM_STATE_INIT) eim_wait_reg <= 1'b0; // fsm is idle, no need to wait any more + // + end + + assign eim_wait_n = ~eim_wait_reg; + + + /* These flags are used to generate 1-cycle pulses to trigger CDC transaction. + * Note that FSM goes from WRITE_LSB to WRITE_MSB and from READ_START to READ_WAIT + * unconditionally, so these flags will always be active for 1 cycle only, which + * is exactly what we need. + */ + + wire arbiter_write_req_pulse = (eim_fsm_state == EIM_FSM_STATE_WRITE_LSB) ? 1'b1 : 1'b0; + wire arbiter_read_req_pulse = (eim_fsm_state == EIM_FSM_STATE_READ_START) ? 1'b1 : 1'b0; + + // + // CDC Block + // + + /* This block is used to transfer request data from BCLK clock domain to SYS_CLK clock domain and + * then transfer acknowledge from SYS_CLK to BCLK clock domain in return. Af first 1+1+14+32 = 48 bits + * are transfered, these are: write flag, read flag, address, write data. During read transaction + * some bogus write data is passed, which is not used later anyway. During read requests 32 bits of data + * are returned, during write requests 32 bits of bogus data are returned, that are never used later. + */ + + eim_arbiter_cdc eim_cdc + ( + .eim_clk (eim_bclk), + + .eim_req (arbiter_write_req_pulse | arbiter_read_req_pulse), + .eim_ack (eim_user_ack), + + .eim_din ({arbiter_write_req_pulse, arbiter_read_req_pulse, eim_addr_latch, da_ro, eim_write_lsb_latch}), + .eim_dout (eim_user_data), + + .sys_clk (sys_clk), + .sys_addr (sys_addr), + .sys_wren (sys_wren), + .sys_data_out (sys_data_out), + .sys_rden (sys_rden), + .sys_data_in (sys_data_in) + ); + + +endmodule |