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[/] [cfi_ctrl/] [trunk/] [rtl/] [verilog/] [cfi_ctrl_engine.v] - Blame information for rev 2

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////////////////////////////////////////////////////////////////// ////
////                                                              //// 
////  Common Flash Interface (CFI) controller                     //// 
////                                                              //// 
////  This file is part of the cfi_ctrl project                   //// 
////  http://opencores.org/project,cfi_ctrl                       //// 
////                                                              //// 
////  Description                                                 //// 
////  See below                                                   //// 
////                                                              //// 
////  To Do:                                                      //// 
////   -                                                          //// 
////                                                              //// 
////  Author(s):                                                  //// 
////      - Julius Baxter, julius@opencores.org                   //// 
////                                                              //// 
////////////////////////////////////////////////////////////////////// 
////                                                              //// 
//// Copyright (C) 2011 Authors and OPENCORES.ORG                 //// 
////                                                              //// 
//// This source file may be used and distributed without         //// 
//// restriction provided that this copyright statement is not    //// 
//// removed from the file and that any derivative work contains  //// 
//// the original copyright notice and the associated disclaimer. //// 
////                                                              //// 
//// This source file is free software; you can redistribute it   //// 
//// and/or modify it under the terms of the GNU Lesser General   //// 
//// Public License as published by the Free Software Foundation; //// 
//// either version 2.1 of the License, or (at your option) any   //// 
//// later version.                                               //// 
////                                                              //// 
//// This source is distributed in the hope that it will be       //// 
//// useful, but WITHOUT ANY WARRANTY; without even the implied   //// 
//// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR      //// 
//// PURPOSE.  See the GNU Lesser General Public License for more //// 
//// details.                                                     //// 
////                                                              //// 
//// You should have received a copy of the GNU Lesser General    //// 
//// Public License along with this source; if not, download it   //// 
//// from http://www.gnu.org/copyleft/lesser.html                 //// 
////                                                              ////
////////////////////////////////////////////////////////////////////// 
/*
 CFI controller engine.
 
 Contains main state machine and bus controls.
 
 Controlled via a simple interface to a bus controller interface.
 
 For now just implements an asynchronous controller.
 
 do_rst_i - reset the flash device
 do_init_i - initialise the device (write "read configuration register")
 do_readstatus_i - read the status of the device
 do_eraseblock_i - erase a block
 do_write_i - write a word an address
 do_read_i - read a word from an address
 
 bus_dat_o - data out to bus controller
 bus_dat_i - data in from bus controller
 bus_req_done_o - bus request done
 
 */
 
 
module cfi_ctrl_engine
  (
 
   clk_i, rst_i,
 
   do_rst_i,
   do_init_i,
   do_readstatus_i,
   do_clearstatus_i,
   do_eraseblock_i,
   do_unlockblock_i,
   do_write_i,
   do_read_i,
   do_readdeviceident_i,
   do_cfiquery_i,
 
   bus_dat_o,
   bus_dat_i,
   bus_adr_i,
   bus_req_done_o,
   bus_busy_o,
 
   flash_dq_io,
   flash_adr_o,
   flash_adv_n_o,
   flash_ce_n_o,
   flash_clk_o,
   flash_oe_n_o,
   flash_rst_n_o,
   flash_wait_i,
   flash_we_n_o,
   flash_wp_n_o
 
   );
 
   parameter flash_dq_width = 16;
   parameter flash_adr_width = 24;
 
   input clk_i, rst_i;
   input do_rst_i,
         do_init_i,
         do_readstatus_i,
         do_clearstatus_i,
         do_eraseblock_i,
         do_unlockblock_i,
         do_write_i,
         do_read_i,
         do_readdeviceident_i,
         do_cfiquery_i;
 
   output reg [flash_dq_width-1:0] bus_dat_o;
   input [flash_dq_width-1:0]       bus_dat_i;
   input [flash_adr_width-1:0]      bus_adr_i;
   output                          bus_req_done_o;
   output                          bus_busy_o;
 
 
   inout [flash_dq_width-1:0]       flash_dq_io;
   output [flash_adr_width-1:0]    flash_adr_o;
 
   output                          flash_adv_n_o;
   output                          flash_ce_n_o;
   output                          flash_clk_o;
   output                          flash_oe_n_o;
   output                          flash_rst_n_o;
   input                           flash_wait_i;
   output                          flash_we_n_o;
   output                          flash_wp_n_o;
 
   wire                            clk, rst;
 
assign clk = clk_i;
assign rst = rst_i;
 
   reg [5:0]                     bus_control_state;
 
   reg [flash_dq_width-1:0]      flash_cmd_to_write;
 
   /* regs for flash bus control signals */
   reg flash_adv_n_r;
   reg flash_ce_n_r;
   reg flash_oe_n_r;
   reg flash_we_n_r;
   reg flash_wp_n_r;
   reg flash_rst_n_r;
   reg [flash_dq_width-1:0]  flash_dq_o_r;
   reg [flash_adr_width-1:0] flash_adr_r;
 
   reg [3:0]                  flash_phy_state;
   reg [3:0]                  flash_phy_ctr;
   wire                      flash_phy_async_wait;
 
`define CFI_PHY_FSM_IDLE        0
`define CFI_PHY_FSM_WRITE_GO    1
`define CFI_PHY_FSM_WRITE_WAIT  2
`define CFI_PHY_FSM_WRITE_DONE  3
`define CFI_PHY_FSM_READ_GO     4
`define CFI_PHY_FSM_READ_WAIT   5
`define CFI_PHY_FSM_READ_DONE   6
`define CFI_PHY_FSM_RESET_GO    7
`define CFI_PHY_FSM_RESET_WAIT  8
`define CFI_PHY_FSM_RESET_DONE  9
 
   /* Defines according to CFI spec */
`define CFI_CMD_DAT_READ_STATUS_REG      8'h70
`define CFI_CMD_DAT_CLEAR_STATUS_REG     8'h50
`define CFI_CMD_DAT_WORD_PROGRAM         8'h40
`define CFI_CMD_DAT_BLOCK_ERASE          8'h20
`define CFI_CMD_DAT_READ_ARRAY           8'hff
`define CFI_CMD_DAT_WRITE_RCR            8'h60
`define CFI_CMD_DAT_CONFIRM_WRITE_RCR    8'h03
`define CFI_CMD_DAT_UNLOCKBLOCKSETUP     8'h60
`define CFI_CMD_DAT_CONFIRM_CMD          8'hd0
`define CFI_CMD_DAT_READDEVICEIDENT      8'h90
`define CFI_CMD_DAT_CFIQUERY             8'h98
 
 
   /* Main bus-controlled FSM states */
`define CFI_FSM_IDLE                   0
`define CFI_FSM_DO_WRITE               1
`define CFI_FSM_DO_WRITE_WAIT          2
`define CFI_FSM_DO_READ                3
`define CFI_FSM_DO_READ_WAIT           4
`define CFI_FSM_DO_BUS_ACK             5
`define CFI_FSM_DO_RESET               6
`define CFI_FSM_DO_RESET_WAIT          7
 
   /* Used to internally track what read more we're in
    2'b00 : read array mode
    2'b01 : read status mode
    else : something else*/
   reg [1:0]                             flash_device_read_mode;
 
   /* Track what read mode we're in */
   always @(posedge clk)
     if (rst)
       flash_device_read_mode <= 2'b00;
     else if (!flash_rst_n_o)
        flash_device_read_mode      <= 2'b00;
     else if (flash_phy_state == `CFI_PHY_FSM_WRITE_DONE) begin
        if (flash_cmd_to_write == `CFI_CMD_DAT_READ_ARRAY)
           flash_device_read_mode <= 2'b00;
        else if (flash_cmd_to_write == `CFI_CMD_DAT_READ_STATUS_REG)
           flash_device_read_mode <= 2'b01;
        else
           /* Some other mode */
           flash_device_read_mode <= 2'b11;
     end
 
   /* Main control state machine, controlled by the bus */
   always @(posedge clk)
     if (rst) begin
       /* Power up and start an asynchronous write to the "read config reg" */
        bus_control_state <= `CFI_FSM_IDLE;
        flash_cmd_to_write <= 0;
     end
     else
       case (bus_control_state)
         `CFI_FSM_IDLE : begin
            if (do_readstatus_i) begin
//             if (flash_device_read_mode != 2'b01) begin
                  flash_cmd_to_write <= `CFI_CMD_DAT_READ_STATUS_REG;
                  bus_control_state <= `CFI_FSM_DO_WRITE;
//             end
//             else begin
//                flash_cmd_to_write <= 0;
//                bus_control_state <= `CFI_FSM_DO_READ;
//             end
            end
            if (do_clearstatus_i) begin
               flash_cmd_to_write <= `CFI_CMD_DAT_CLEAR_STATUS_REG;
               bus_control_state <= `CFI_FSM_DO_WRITE;
            end
            if (do_eraseblock_i) begin
               flash_cmd_to_write <= `CFI_CMD_DAT_BLOCK_ERASE;
               bus_control_state <= `CFI_FSM_DO_WRITE;
            end
            if (do_write_i) begin
               flash_cmd_to_write <= `CFI_CMD_DAT_WORD_PROGRAM;
               bus_control_state <= `CFI_FSM_DO_WRITE;
            end
            if (do_read_i) begin
               if (flash_device_read_mode != 2'b00) begin
                  flash_cmd_to_write <= `CFI_CMD_DAT_READ_ARRAY;
                  bus_control_state <= `CFI_FSM_DO_WRITE;
               end
               else begin
                  flash_cmd_to_write <= 0;
                  bus_control_state <= `CFI_FSM_DO_READ;
               end
            end
            if (do_unlockblock_i) begin
               flash_cmd_to_write <= `CFI_CMD_DAT_UNLOCKBLOCKSETUP;
               bus_control_state <= `CFI_FSM_DO_WRITE;
            end
            if (do_rst_i) begin
               flash_cmd_to_write <= 0;
               bus_control_state <= `CFI_FSM_DO_RESET;
            end
            if (do_readdeviceident_i) begin
               flash_cmd_to_write <= `CFI_CMD_DAT_READDEVICEIDENT;
               bus_control_state <= `CFI_FSM_DO_WRITE;
            end
            if (do_cfiquery_i) begin
               flash_cmd_to_write <= `CFI_CMD_DAT_CFIQUERY;
               bus_control_state <= `CFI_FSM_DO_WRITE;
            end
 
         end // case: `CFI_FSM_IDLE
         `CFI_FSM_DO_WRITE : begin
            bus_control_state <= `CFI_FSM_DO_WRITE_WAIT;
         end
         `CFI_FSM_DO_WRITE_WAIT : begin
            /* Wait for phy controller to finish the write command */
            if (flash_phy_state==`CFI_PHY_FSM_WRITE_DONE) begin
               if (flash_cmd_to_write == `CFI_CMD_DAT_READ_STATUS_REG ||
                   flash_cmd_to_write == `CFI_CMD_DAT_READ_ARRAY ||
                   flash_cmd_to_write == `CFI_CMD_DAT_READDEVICEIDENT ||
                   flash_cmd_to_write == `CFI_CMD_DAT_CFIQUERY) begin
                  /* we just changed the read mode, so go ahead and do the
                   read */
                  bus_control_state <= `CFI_FSM_DO_READ;
               end
               else if (flash_cmd_to_write == `CFI_CMD_DAT_WORD_PROGRAM) begin
                  /* Setting up to do a word write, go to write again */
                  /* clear the command, to use the incoming data from the bus */
                  flash_cmd_to_write <= 0;
                  bus_control_state <= `CFI_FSM_DO_WRITE;
               end
               else if (flash_cmd_to_write == `CFI_CMD_DAT_BLOCK_ERASE ||
                        flash_cmd_to_write == `CFI_CMD_DAT_UNLOCKBLOCKSETUP)
               begin
                  /* first stage of a two-stage command requiring confirm */
                  bus_control_state <= `CFI_FSM_DO_WRITE;
                  flash_cmd_to_write <= `CFI_CMD_DAT_CONFIRM_CMD;
               end
               else
                  /* All other operations should see us acking the bus */
                  bus_control_state <= `CFI_FSM_DO_BUS_ACK;
            end
         end // case: `CFI_FSM_DO_WRITE_WAIT
          `CFI_FSM_DO_READ : begin
             bus_control_state <= `CFI_FSM_DO_READ_WAIT;
          end
          `CFI_FSM_DO_READ_WAIT : begin
             if (flash_phy_state==`CFI_PHY_FSM_READ_DONE) begin
                bus_control_state <= `CFI_FSM_DO_BUS_ACK;
             end
          end
          `CFI_FSM_DO_BUS_ACK :
             bus_control_state <= `CFI_FSM_IDLE;
         `CFI_FSM_DO_RESET :
           bus_control_state <= `CFI_FSM_DO_RESET_WAIT;
         `CFI_FSM_DO_RESET_WAIT : begin
            if (flash_phy_state==`CFI_PHY_FSM_RESET_DONE)
              bus_control_state <= `CFI_FSM_IDLE;
         end
          default :
             bus_control_state <= `CFI_FSM_IDLE;
       endcase // case (bus_control_state)
 
/* Tell the bus we're done */
assign bus_req_done_o = (bus_control_state==`CFI_FSM_DO_BUS_ACK);
assign bus_busy_o = !(bus_control_state == `CFI_FSM_IDLE);
 
/* Sample flash data for the system bus interface */
always @(posedge clk)
   if (rst)
      bus_dat_o <= 0;
   else if ((flash_phy_state == `CFI_PHY_FSM_READ_WAIT) &&
            /* Wait for t_vlqv */
            (!flash_phy_async_wait))
      /* Sample flash data */
      bus_dat_o <= flash_dq_io;
 
/* Flash physical interface control state machine */
always @(posedge clk)
   if (rst)
   begin
      flash_adv_n_r <= 1'b0;
      flash_ce_n_r  <= 1'b1;
      flash_oe_n_r  <= 1'b1;
      flash_we_n_r  <= 1'b1;
      flash_dq_o_r  <= 0;
      flash_adr_r   <= 0;
      flash_rst_n_r <= 0;
 
      flash_phy_state <= `CFI_PHY_FSM_IDLE;
   end
   else
   begin
      case (flash_phy_state)
         `CFI_PHY_FSM_IDLE : begin
            flash_rst_n_r <= 1'b1;
            flash_ce_n_r <= 1'b0;
 
            /* Take address from the bus controller */
            flash_adr_r  <= bus_adr_i;
 
            /* Wait for a read or write command */
            if (bus_control_state == `CFI_FSM_DO_WRITE)
            begin
               flash_phy_state <= `CFI_PHY_FSM_WRITE_GO;
               /* Are we going to write a command? */
               if (flash_cmd_to_write) begin
                  flash_dq_o_r <= {{(flash_dq_width-8){1'b0}},
                                   flash_cmd_to_write};
               end
               else
                  flash_dq_o_r <= bus_dat_i;
 
            end
            if (bus_control_state == `CFI_FSM_DO_READ) begin
               flash_phy_state <= `CFI_PHY_FSM_READ_GO;
            end
            if (bus_control_state == `CFI_FSM_DO_RESET) begin
               flash_phy_state <= `CFI_PHY_FSM_RESET_GO;
            end
         end
         `CFI_PHY_FSM_WRITE_GO: begin
            /* Assert CE, WE */
            flash_we_n_r <= 1'b0;
 
            flash_phy_state <= `CFI_PHY_FSM_WRITE_WAIT;
         end
         `CFI_PHY_FSM_WRITE_WAIT: begin
            /* Wait for t_wlwh */
            if (!flash_phy_async_wait) begin
               flash_phy_state <= `CFI_PHY_FSM_WRITE_DONE;
               flash_we_n_r <= 1'b1;
            end
         end
         `CFI_PHY_FSM_WRITE_DONE: begin
            flash_phy_state <= `CFI_PHY_FSM_IDLE;
         end
 
         `CFI_PHY_FSM_READ_GO: begin
            /* Assert CE, OE */
            /*flash_adv_n_r <= 1'b1;*/
            flash_ce_n_r <= 1'b0;
            flash_oe_n_r <= 1'b0;
            flash_phy_state <= `CFI_PHY_FSM_READ_WAIT;
         end
         `CFI_PHY_FSM_READ_WAIT: begin
            /* Wait for t_vlqv */
            if (!flash_phy_async_wait) begin
               flash_oe_n_r    <= 1'b1;
               flash_phy_state <= `CFI_PHY_FSM_READ_DONE;
            end
         end
         `CFI_PHY_FSM_READ_DONE: begin
            flash_phy_state <= `CFI_PHY_FSM_IDLE;
         end
        `CFI_PHY_FSM_RESET_GO: begin
           flash_phy_state <= `CFI_PHY_FSM_RESET_WAIT;
           flash_rst_n_r <= 1'b0;
           flash_oe_n_r <= 1'b1;
        end
        `CFI_PHY_FSM_RESET_WAIT : begin
           if (!flash_phy_async_wait) begin
              flash_rst_n_r    <= 1'b1;
              flash_phy_state <= `CFI_PHY_FSM_RESET_DONE;
           end
        end
        `CFI_PHY_FSM_RESET_DONE : begin
           flash_phy_state <= `CFI_PHY_FSM_IDLE;
        end
         default:
            flash_phy_state <= `CFI_PHY_FSM_IDLE;
      endcase
   end
 
/* Defaults are for 95ns access time part, 66MHz (15.15ns) system clock */
/* wlwh: cycles for WE assert to WE de-assert: write time */
parameter cfi_part_wlwh_cycles = 4; /* wlwh = 50ns, tck = 15ns, cycles = 4*/
/* elqv: cycles from adress  to data valid */
parameter cfi_part_elqv_cycles = 7; /* tsop 256mbit elqv = 95ns, tck = 15ns, cycles = 6*/
 
assign flash_phy_async_wait = (|flash_phy_ctr);
 
/* Load counter with wait times in cycles, determined by parameters. */
always @(posedge clk)
   if (rst)
      flash_phy_ctr <= 0;
   else if (flash_phy_state==`CFI_PHY_FSM_WRITE_GO)
      flash_phy_ctr <= cfi_part_wlwh_cycles - 1;
   else if (flash_phy_state==`CFI_PHY_FSM_READ_GO)
     flash_phy_ctr <= cfi_part_elqv_cycles - 2;
   else if (flash_phy_state==`CFI_PHY_FSM_RESET_GO)
     flash_phy_ctr <= 10;
   else if (|flash_phy_ctr)
      flash_phy_ctr <= flash_phy_ctr - 1;
 
   /* Signal to indicate when we should drive the data bus */
   wire flash_bus_write_enable;
   assign flash_bus_write_enable = (bus_control_state == `CFI_FSM_DO_WRITE) |
                                   (bus_control_state == `CFI_FSM_DO_WRITE_WAIT);
 
/* Assign signals to physical bus */
assign flash_dq_io = flash_bus_write_enable ? flash_dq_o_r :
                     {flash_dq_width{1'bz}};
assign flash_adr_o = flash_adr_r;
assign flash_adv_n_o = flash_adv_n_r;
assign flash_wp_n_o = 1'b1; /* Never write protect */
assign flash_ce_n_o = flash_ce_n_r;
assign flash_oe_n_o = flash_oe_n_r;
assign flash_we_n_o = flash_we_n_r;
assign flash_clk_o = 1'b1;
assign flash_rst_n_o = flash_rst_n_r;
endmodule // cfi_ctrl_engine
 
 
 
 

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Subversion Repositories cfi_ctrl

[/] [cfi_ctrl/] [trunk/] [rtl/] [verilog/] [cfi_ctrl_engine.v] - Blame information for rev 2

Line No.	Rev	Author	Line
1	2	julius	`////////////////////////////////////////////////////////////////// ////`
2			`//// ////`
3			`//// Common Flash Interface (CFI) controller ////`
4			`//// ////`
5			`//// This file is part of the cfi_ctrl project ////`
6			`//// http://opencores.org/project,cfi_ctrl ////`
7			`//// ////`
8			`//// Description ////`
9			`//// See below ////`
10			`//// ////`
11			`//// To Do: ////`
12			`//// - ////`
13			`//// ////`
14			`//// Author(s): ////`
15			`//// - Julius Baxter, julius@opencores.org ////`
16			`//// ////`
17			`//////////////////////////////////////////////////////////////////////`
18			`//// ////`
19			`//// Copyright (C) 2011 Authors and OPENCORES.ORG ////`
20			`//// ////`
21			`//// This source file may be used and distributed without ////`
22			`//// restriction provided that this copyright statement is not ////`
23			`//// removed from the file and that any derivative work contains ////`
24			`//// the original copyright notice and the associated disclaimer. ////`
25			`//// ////`
26			`//// This source file is free software; you can redistribute it ////`
27			`//// and/or modify it under the terms of the GNU Lesser General ////`
28			`//// Public License as published by the Free Software Foundation; ////`
29			`//// either version 2.1 of the License, or (at your option) any ////`
30			`//// later version. ////`
31			`//// ////`
32			`//// This source is distributed in the hope that it will be ////`
33			`//// useful, but WITHOUT ANY WARRANTY; without even the implied ////`
34			`//// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR ////`
35			`//// PURPOSE. See the GNU Lesser General Public License for more ////`
36			`//// details. ////`
37			`//// ////`
38			`//// You should have received a copy of the GNU Lesser General ////`
39			`//// Public License along with this source; if not, download it ////`
40			`//// from http://www.gnu.org/copyleft/lesser.html ////`
41			`//// ////`
42			`//////////////////////////////////////////////////////////////////////`
43			`/*`
44			`CFI controller engine.`
45
46			`Contains main state machine and bus controls.`
47
48			`Controlled via a simple interface to a bus controller interface.`
49
50			`For now just implements an asynchronous controller.`
51
52			`do_rst_i - reset the flash device`
53			`do_init_i - initialise the device (write "read configuration register")`
54			`do_readstatus_i - read the status of the device`
55			`do_eraseblock_i - erase a block`
56			`do_write_i - write a word an address`
57			`do_read_i - read a word from an address`
58
59			`bus_dat_o - data out to bus controller`
60			`bus_dat_i - data in from bus controller`
61			`bus_req_done_o - bus request done`
62
63			`*/`
64
65
66			`module cfi_ctrl_engine`
67			`(`
68
69			`clk_i, rst_i,`
70
71			`do_rst_i,`
72			`do_init_i,`
73			`do_readstatus_i,`
74			`do_clearstatus_i,`
75			`do_eraseblock_i,`
76			`do_unlockblock_i,`
77			`do_write_i,`
78			`do_read_i,`
79			`do_readdeviceident_i,`
80			`do_cfiquery_i,`
81
82			`bus_dat_o,`
83			`bus_dat_i,`
84			`bus_adr_i,`
85			`bus_req_done_o,`
86			`bus_busy_o,`
87
88			`flash_dq_io,`
89			`flash_adr_o,`
90			`flash_adv_n_o,`
91			`flash_ce_n_o,`
92			`flash_clk_o,`
93			`flash_oe_n_o,`
94			`flash_rst_n_o,`
95			`flash_wait_i,`
96			`flash_we_n_o,`
97			`flash_wp_n_o`
98
99			`);`
100
101			`parameter flash_dq_width = 16;`
102			`parameter flash_adr_width = 24;`
103
104			`input clk_i, rst_i;`
105			`input do_rst_i,`
106			`do_init_i,`
107			`do_readstatus_i,`
108			`do_clearstatus_i,`
109			`do_eraseblock_i,`
110			`do_unlockblock_i,`
111			`do_write_i,`
112			`do_read_i,`
113			`do_readdeviceident_i,`
114			`do_cfiquery_i;`
115
116			`output reg [flash_dq_width-1:0] bus_dat_o;`
117			`input [flash_dq_width-1:0] bus_dat_i;`
118			`input [flash_adr_width-1:0] bus_adr_i;`
119			`output bus_req_done_o;`
120			`output bus_busy_o;`
121
122
123			`inout [flash_dq_width-1:0] flash_dq_io;`
124			`output [flash_adr_width-1:0] flash_adr_o;`
125
126			`output flash_adv_n_o;`
127			`output flash_ce_n_o;`
128			`output flash_clk_o;`
129			`output flash_oe_n_o;`
130			`output flash_rst_n_o;`
131			`input flash_wait_i;`
132			`output flash_we_n_o;`
133			`output flash_wp_n_o;`
134
135			`wire clk, rst;`
136
137			`assign clk = clk_i;`
138			`assign rst = rst_i;`
139
140			`reg [5:0] bus_control_state;`
141
142			`reg [flash_dq_width-1:0] flash_cmd_to_write;`
143
144			`/* regs for flash bus control signals */`
145			`reg flash_adv_n_r;`
146			`reg flash_ce_n_r;`
147			`reg flash_oe_n_r;`
148			`reg flash_we_n_r;`
149			`reg flash_wp_n_r;`
150			`reg flash_rst_n_r;`
151			`reg [flash_dq_width-1:0] flash_dq_o_r;`
152			`reg [flash_adr_width-1:0] flash_adr_r;`
153
154			`reg [3:0] flash_phy_state;`
155			`reg [3:0] flash_phy_ctr;`
156			`wire flash_phy_async_wait;`
157
158			`define CFI_PHY_FSM_IDLE 0
159			`define CFI_PHY_FSM_WRITE_GO 1
160			`define CFI_PHY_FSM_WRITE_WAIT 2
161			`define CFI_PHY_FSM_WRITE_DONE 3
162			`define CFI_PHY_FSM_READ_GO 4
163			`define CFI_PHY_FSM_READ_WAIT 5
164			`define CFI_PHY_FSM_READ_DONE 6
165			`define CFI_PHY_FSM_RESET_GO 7
166			`define CFI_PHY_FSM_RESET_WAIT 8
167			`define CFI_PHY_FSM_RESET_DONE 9
168
169			`/* Defines according to CFI spec */`
170			`define CFI_CMD_DAT_READ_STATUS_REG 8'h70
171			`define CFI_CMD_DAT_CLEAR_STATUS_REG 8'h50
172			`define CFI_CMD_DAT_WORD_PROGRAM 8'h40
173			`define CFI_CMD_DAT_BLOCK_ERASE 8'h20
174			`define CFI_CMD_DAT_READ_ARRAY 8'hff
175			`define CFI_CMD_DAT_WRITE_RCR 8'h60
176			`define CFI_CMD_DAT_CONFIRM_WRITE_RCR 8'h03
177			`define CFI_CMD_DAT_UNLOCKBLOCKSETUP 8'h60
178			`define CFI_CMD_DAT_CONFIRM_CMD 8'hd0
179			`define CFI_CMD_DAT_READDEVICEIDENT 8'h90
180			`define CFI_CMD_DAT_CFIQUERY 8'h98
181
182
183			`/* Main bus-controlled FSM states */`
184			`define CFI_FSM_IDLE 0
185			`define CFI_FSM_DO_WRITE 1
186			`define CFI_FSM_DO_WRITE_WAIT 2
187			`define CFI_FSM_DO_READ 3
188			`define CFI_FSM_DO_READ_WAIT 4
189			`define CFI_FSM_DO_BUS_ACK 5
190			`define CFI_FSM_DO_RESET 6
191			`define CFI_FSM_DO_RESET_WAIT 7
192
193			`/* Used to internally track what read more we're in`
194			`2'b00 : read array mode`
195			`2'b01 : read status mode`
196			`else : something else*/`
197			`reg [1:0] flash_device_read_mode;`
198
199			`/* Track what read mode we're in */`
200			`always @(posedge clk)`
201			`if (rst)`
202			`flash_device_read_mode <= 2'b00;`
203			`else if (!flash_rst_n_o)`
204			`flash_device_read_mode <= 2'b00;`
205			else if (flash_phy_state == `CFI_PHY_FSM_WRITE_DONE) begin
206			if (flash_cmd_to_write == `CFI_CMD_DAT_READ_ARRAY)
207			`flash_device_read_mode <= 2'b00;`
208			else if (flash_cmd_to_write == `CFI_CMD_DAT_READ_STATUS_REG)
209			`flash_device_read_mode <= 2'b01;`
210			`else`
211			`/* Some other mode */`
212			`flash_device_read_mode <= 2'b11;`
213			`end`
214
215			`/* Main control state machine, controlled by the bus */`
216			`always @(posedge clk)`
217			`if (rst) begin`
218			`/* Power up and start an asynchronous write to the "read config reg" */`
219			bus_control_state <= `CFI_FSM_IDLE;
220			`flash_cmd_to_write <= 0;`
221			`end`
222			`else`
223			`case (bus_control_state)`
224			`CFI_FSM_IDLE : begin
225			`if (do_readstatus_i) begin`
226			`// if (flash_device_read_mode != 2'b01) begin`
227			flash_cmd_to_write <= `CFI_CMD_DAT_READ_STATUS_REG;
228			bus_control_state <= `CFI_FSM_DO_WRITE;
229			`// end`
230			`// else begin`
231			`// flash_cmd_to_write <= 0;`
232			// bus_control_state <= `CFI_FSM_DO_READ;
233			`// end`
234			`end`
235			`if (do_clearstatus_i) begin`
236			flash_cmd_to_write <= `CFI_CMD_DAT_CLEAR_STATUS_REG;
237			bus_control_state <= `CFI_FSM_DO_WRITE;
238			`end`
239			`if (do_eraseblock_i) begin`
240			flash_cmd_to_write <= `CFI_CMD_DAT_BLOCK_ERASE;
241			bus_control_state <= `CFI_FSM_DO_WRITE;
242			`end`
243			`if (do_write_i) begin`
244			flash_cmd_to_write <= `CFI_CMD_DAT_WORD_PROGRAM;
245			bus_control_state <= `CFI_FSM_DO_WRITE;
246			`end`
247			`if (do_read_i) begin`
248			`if (flash_device_read_mode != 2'b00) begin`
249			flash_cmd_to_write <= `CFI_CMD_DAT_READ_ARRAY;
250			bus_control_state <= `CFI_FSM_DO_WRITE;
251			`end`
252			`else begin`
253			`flash_cmd_to_write <= 0;`
254			bus_control_state <= `CFI_FSM_DO_READ;
255			`end`
256			`end`
257			`if (do_unlockblock_i) begin`
258			flash_cmd_to_write <= `CFI_CMD_DAT_UNLOCKBLOCKSETUP;
259			bus_control_state <= `CFI_FSM_DO_WRITE;
260			`end`
261			`if (do_rst_i) begin`
262			`flash_cmd_to_write <= 0;`
263			bus_control_state <= `CFI_FSM_DO_RESET;
264			`end`
265			`if (do_readdeviceident_i) begin`
266			flash_cmd_to_write <= `CFI_CMD_DAT_READDEVICEIDENT;
267			bus_control_state <= `CFI_FSM_DO_WRITE;
268			`end`
269			`if (do_cfiquery_i) begin`
270			flash_cmd_to_write <= `CFI_CMD_DAT_CFIQUERY;
271			bus_control_state <= `CFI_FSM_DO_WRITE;
272			`end`
273
274			end // case: `CFI_FSM_IDLE
275			`CFI_FSM_DO_WRITE : begin
276			bus_control_state <= `CFI_FSM_DO_WRITE_WAIT;
277			`end`
278			`CFI_FSM_DO_WRITE_WAIT : begin
279			`/* Wait for phy controller to finish the write command */`
280			if (flash_phy_state==`CFI_PHY_FSM_WRITE_DONE) begin
281			if (flash_cmd_to_write == `CFI_CMD_DAT_READ_STATUS_REG \|\|
282			flash_cmd_to_write == `CFI_CMD_DAT_READ_ARRAY \|\|
283			flash_cmd_to_write == `CFI_CMD_DAT_READDEVICEIDENT \|\|
284			flash_cmd_to_write == `CFI_CMD_DAT_CFIQUERY) begin
285			`/* we just changed the read mode, so go ahead and do the`
286			`read */`
287			bus_control_state <= `CFI_FSM_DO_READ;
288			`end`
289			else if (flash_cmd_to_write == `CFI_CMD_DAT_WORD_PROGRAM) begin
290			`/* Setting up to do a word write, go to write again */`
291			`/* clear the command, to use the incoming data from the bus */`
292			`flash_cmd_to_write <= 0;`
293			bus_control_state <= `CFI_FSM_DO_WRITE;
294			`end`
295			else if (flash_cmd_to_write == `CFI_CMD_DAT_BLOCK_ERASE \|\|
296			flash_cmd_to_write == `CFI_CMD_DAT_UNLOCKBLOCKSETUP)
297			`begin`
298			`/* first stage of a two-stage command requiring confirm */`
299			bus_control_state <= `CFI_FSM_DO_WRITE;
300			flash_cmd_to_write <= `CFI_CMD_DAT_CONFIRM_CMD;
301			`end`
302			`else`
303			`/* All other operations should see us acking the bus */`
304			bus_control_state <= `CFI_FSM_DO_BUS_ACK;
305			`end`
306			end // case: `CFI_FSM_DO_WRITE_WAIT
307			`CFI_FSM_DO_READ : begin
308			bus_control_state <= `CFI_FSM_DO_READ_WAIT;
309			`end`
310			`CFI_FSM_DO_READ_WAIT : begin
311			if (flash_phy_state==`CFI_PHY_FSM_READ_DONE) begin
312			bus_control_state <= `CFI_FSM_DO_BUS_ACK;
313			`end`
314			`end`
315			`CFI_FSM_DO_BUS_ACK :
316			bus_control_state <= `CFI_FSM_IDLE;
317			`CFI_FSM_DO_RESET :
318			bus_control_state <= `CFI_FSM_DO_RESET_WAIT;
319			`CFI_FSM_DO_RESET_WAIT : begin
320			if (flash_phy_state==`CFI_PHY_FSM_RESET_DONE)
321			bus_control_state <= `CFI_FSM_IDLE;
322			`end`
323			`default :`
324			bus_control_state <= `CFI_FSM_IDLE;
325			`endcase // case (bus_control_state)`
326
327			`/* Tell the bus we're done */`
328			assign bus_req_done_o = (bus_control_state==`CFI_FSM_DO_BUS_ACK);
329			assign bus_busy_o = !(bus_control_state == `CFI_FSM_IDLE);
330
331			`/* Sample flash data for the system bus interface */`
332			`always @(posedge clk)`
333			`if (rst)`
334			`bus_dat_o <= 0;`
335			else if ((flash_phy_state == `CFI_PHY_FSM_READ_WAIT) &&
336			`/* Wait for t_vlqv */`
337			`(!flash_phy_async_wait))`
338			`/* Sample flash data */`
339			`bus_dat_o <= flash_dq_io;`
340
341			`/* Flash physical interface control state machine */`
342			`always @(posedge clk)`
343			`if (rst)`
344			`begin`
345			`flash_adv_n_r <= 1'b0;`
346			`flash_ce_n_r <= 1'b1;`
347			`flash_oe_n_r <= 1'b1;`
348			`flash_we_n_r <= 1'b1;`
349			`flash_dq_o_r <= 0;`
350			`flash_adr_r <= 0;`
351			`flash_rst_n_r <= 0;`
352
353			flash_phy_state <= `CFI_PHY_FSM_IDLE;
354			`end`
355			`else`
356			`begin`
357			`case (flash_phy_state)`
358			`CFI_PHY_FSM_IDLE : begin
359			`flash_rst_n_r <= 1'b1;`
360			`flash_ce_n_r <= 1'b0;`
361
362			`/* Take address from the bus controller */`
363			`flash_adr_r <= bus_adr_i;`
364
365			`/* Wait for a read or write command */`
366			if (bus_control_state == `CFI_FSM_DO_WRITE)
367			`begin`
368			flash_phy_state <= `CFI_PHY_FSM_WRITE_GO;
369			`/* Are we going to write a command? */`
370			`if (flash_cmd_to_write) begin`
371			`flash_dq_o_r <= {{(flash_dq_width-8){1'b0}},`
372			`flash_cmd_to_write};`
373			`end`
374			`else`
375			`flash_dq_o_r <= bus_dat_i;`
376
377			`end`
378			if (bus_control_state == `CFI_FSM_DO_READ) begin
379			flash_phy_state <= `CFI_PHY_FSM_READ_GO;
380			`end`
381			if (bus_control_state == `CFI_FSM_DO_RESET) begin
382			flash_phy_state <= `CFI_PHY_FSM_RESET_GO;
383			`end`
384			`end`
385			`CFI_PHY_FSM_WRITE_GO: begin
386			`/* Assert CE, WE */`
387			`flash_we_n_r <= 1'b0;`
388
389			flash_phy_state <= `CFI_PHY_FSM_WRITE_WAIT;
390			`end`
391			`CFI_PHY_FSM_WRITE_WAIT: begin
392			`/* Wait for t_wlwh */`
393			`if (!flash_phy_async_wait) begin`
394			flash_phy_state <= `CFI_PHY_FSM_WRITE_DONE;
395			`flash_we_n_r <= 1'b1;`
396			`end`
397			`end`
398			`CFI_PHY_FSM_WRITE_DONE: begin
399			flash_phy_state <= `CFI_PHY_FSM_IDLE;
400			`end`
401
402			`CFI_PHY_FSM_READ_GO: begin
403			`/* Assert CE, OE */`
404			`/flash_adv_n_r <= 1'b1;/`
405			`flash_ce_n_r <= 1'b0;`
406			`flash_oe_n_r <= 1'b0;`
407			flash_phy_state <= `CFI_PHY_FSM_READ_WAIT;
408			`end`
409			`CFI_PHY_FSM_READ_WAIT: begin
410			`/* Wait for t_vlqv */`
411			`if (!flash_phy_async_wait) begin`
412			`flash_oe_n_r <= 1'b1;`
413			flash_phy_state <= `CFI_PHY_FSM_READ_DONE;
414			`end`
415			`end`
416			`CFI_PHY_FSM_READ_DONE: begin
417			flash_phy_state <= `CFI_PHY_FSM_IDLE;
418			`end`
419			`CFI_PHY_FSM_RESET_GO: begin
420			flash_phy_state <= `CFI_PHY_FSM_RESET_WAIT;
421			`flash_rst_n_r <= 1'b0;`
422			`flash_oe_n_r <= 1'b1;`
423			`end`
424			`CFI_PHY_FSM_RESET_WAIT : begin
425			`if (!flash_phy_async_wait) begin`
426			`flash_rst_n_r <= 1'b1;`
427			flash_phy_state <= `CFI_PHY_FSM_RESET_DONE;
428			`end`
429			`end`
430			`CFI_PHY_FSM_RESET_DONE : begin
431			flash_phy_state <= `CFI_PHY_FSM_IDLE;
432			`end`
433			`default:`
434			flash_phy_state <= `CFI_PHY_FSM_IDLE;
435			`endcase`
436			`end`
437
438			`/* Defaults are for 95ns access time part, 66MHz (15.15ns) system clock */`
439			`/* wlwh: cycles for WE assert to WE de-assert: write time */`
440			`parameter cfi_part_wlwh_cycles = 4; /* wlwh = 50ns, tck = 15ns, cycles = 4*/`
441			`/* elqv: cycles from adress to data valid */`
442			`parameter cfi_part_elqv_cycles = 7; /* tsop 256mbit elqv = 95ns, tck = 15ns, cycles = 6*/`
443
444			`assign flash_phy_async_wait = (\|flash_phy_ctr);`
445
446			`/* Load counter with wait times in cycles, determined by parameters. */`
447			`always @(posedge clk)`
448			`if (rst)`
449			`flash_phy_ctr <= 0;`
450			else if (flash_phy_state==`CFI_PHY_FSM_WRITE_GO)
451			`flash_phy_ctr <= cfi_part_wlwh_cycles - 1;`
452			else if (flash_phy_state==`CFI_PHY_FSM_READ_GO)
453			`flash_phy_ctr <= cfi_part_elqv_cycles - 2;`
454			else if (flash_phy_state==`CFI_PHY_FSM_RESET_GO)
455			`flash_phy_ctr <= 10;`
456			`else if (\|flash_phy_ctr)`
457			`flash_phy_ctr <= flash_phy_ctr - 1;`
458
459			`/* Signal to indicate when we should drive the data bus */`
460			`wire flash_bus_write_enable;`
461			assign flash_bus_write_enable = (bus_control_state == `CFI_FSM_DO_WRITE) \|
462			(bus_control_state == `CFI_FSM_DO_WRITE_WAIT);
463
464			`/* Assign signals to physical bus */`
465			`assign flash_dq_io = flash_bus_write_enable ? flash_dq_o_r :`
466			`{flash_dq_width{1'bz}};`
467			`assign flash_adr_o = flash_adr_r;`
468			`assign flash_adv_n_o = flash_adv_n_r;`
469			`assign flash_wp_n_o = 1'b1; /* Never write protect */`
470			`assign flash_ce_n_o = flash_ce_n_r;`
471			`assign flash_oe_n_o = flash_oe_n_r;`
472			`assign flash_we_n_o = flash_we_n_r;`
473			`assign flash_clk_o = 1'b1;`
474			`assign flash_rst_n_o = flash_rst_n_r;`
475			`endmodule // cfi_ctrl_engine`
476
477
478
479