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Partial implementation of SDC AHBLite interface.

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This commit is contained in:
Ross Thompson 2021-09-23 17:45:45 -05:00
parent 0f7be5e591
commit 9ed7a1f494
1 changed files with 144 additions and 7 deletions
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147
wally-pipelined/src/sdc/SDC.sv
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@ -55,9 +55,27 @@ module SDC
logic initTrans;
logic RegRead;
logic RegWrite;
logic [4:0] HADDRDelay;
// *** reduce size later
// Register outputs
logic [31:0] CLKDiv;
logic [2:0] Command;
logic [`XLEN-1:9] Address;
logic SDCDone;
logic [2:0] ErrorCode;
logic InvalidCommand;
logic Done;
logic Busy;
logic StartCLKDivUpdate;
logic CLKDivUpdateEn;
logic SDCLKEN;
// registers
@ -70,6 +88,23 @@ module SDC
//| 0x10 | address | 8 | address of operation |
//| 0x18 | data | 8 | Data Bus interface |
// Status contains
// Status[0] busy
// Status[1] done
// Status[2] invalid command
// Status[5:3] error code
// control contains 3 bit command
// control[2:0]
// 000 nop op
// xx1 initialize
// 010 Write no implemented
// 100 Read
// 110 Atomic read/write not implemented
// size is fixed to 512. Read only
// Currently using a mailbox style interface. Data is passed through the Data register (0x10)
// The card will support 3 operations
// 1. initialize
@ -81,12 +116,114 @@ module SDC
// currently does not support writes
assign InitTrans = HREADY & HSELTSDC & (HTRANS != 2'b00);
assign RegWrite = InitTrans & HWRITE;
assign InitTrans = HREADY & HSELSDC & (HTRANS != 2'b00);
assign RegRead = InitTrans & ~HWRITE;
// AHBLite Spec has write data 1 cycle after write command
flopr #(1) RegWriteReg(HCLK, ~HRESETn, InitTrans & HWRITE, RegWrite);
// *** need to delay
flopenl #(32) CLKDivReg(HCLK, ~HRESETn, , HADDR == '0 & RegWrite, HWRITE, `SDCCLKDIV, CLKDiv);
flopr #(5) HADDRReg(HCLK, ~HRESETn, HADDR, HADDRDelay);
assign StartCLKDivUpdate = HADDRDelay == '0 & RegWrite;
flopenl #(32) CLKDivReg(HCLK, ~HRESETn, CLKDivUpdateEn, HWDATA[31:0], `SDCCLKDIV, CLKDiv);
// Control reg
flopenl #(3) CommandReg(HCLK, ~HRESETn, (HADDRDelay == 'h8 & RegWrite) | (SDCDone),
SDCDone ? '0 : HWDATA[2:0], '0, Command);
flopenr #(`XLEN-9) AddressReg(HCLK, ~HRESETn, (HADDRDelay == 'h10 & RegWrite),
HWDATA[`XLEN-1:9], Address);
flopen #(`XLEN) DataReg(HCLK, (HADDRDelay == 'h18 & RegWrite) | (SDCDataValid),
SDCDataValid ? SDCReadData : HWDATA, ReadData);
generate
if(`XLEN == 64) begin
always_comb
case(HADDRDelay[4:2])
'h0: HREADSDC = {32'b0, CLKDiv};
'h4: HREADSDC = {`XLEN-6'b0, ErrorCode, InvalidCommand, Done, Busy};
'h8: HREADSDC = {`XLEN-3'b0, Command};
'hC: HREADSDC = 'h200;
'h10: HREADSDC = Address;
'h18: HREADSDC = ReadData;
default: HREADSDC = {32'b0, CLKDiv};
endcase
end else begin
always_comb
case(HADDRDelay[4:2])
'h0: HREADSDC = CLKDiv;
'h4: HREADSDC = {ErrorCode, InvalidCommand, Done, Busy};
'h8: HREADSDC = Command;
'hC: HREADSDC = 'h200;
'h10: HREADSDC = Address[31:0];
'h14: HREADSDC = Address[63:32];
'h18: HREADSDC = ReadData[31:0];
'h1C: HREADSDC = ReadData[63:32];
default: HREADSDC = CLKDiv;
endcase
end
endgenerate
typedef enum {STATE_READY,
// clock update states
STATE_CLK_DIV1,
STATE_CLK_DIV2,
STATE_CLK_DIV3,
STATE_CLK_DIV4,
// restart SDC
STATE_RESTART,
// SDC operation
STATE_PROCESS_CMD
} statetype;
statetype CurrState, NextState;
always_ff @(posedge HCLK, posedge ~HRESETn)
if (~HRESETn) CurrState <= #1 STATE_READY;
else CurrState <= #1 NextState;
always_comb begin
CLKDivUpdateEn = 1'b0;
HREADYSDC = 1'b0;
SDCLKEN = 1'b1;
case (CurrState)
STATE_READY : begin
if (StartCLKDivUpdate)begin
NextState = STATE_CLK_DIV1;
HREADYSDC = 1'b0;
/* -----\/----- EXCLUDED -----\/-----
end else if () begin
-----/\----- EXCLUDED -----/\----- */
end else begin
NextState = STATE_READY;
HREADYSDC = 1'b1;
end
end
STATE_CLK_DIV1: begin
NextState = STATE_CLK_DIV2;
SDCLKEN = 1'b0;
end
STATE_CLK_DIV2: begin
NextState = STATE_CLK_DIV3;
CLKDivUpdateEn = 1'b1;
SDCLKEN = 1'b0;
end
STATE_CLK_DIV3: begin
NextState = STATE_CLK_DIV4;
SDCLKEN = 1'b0;
end
STATE_CLK_DIV4: begin
NextState = STATE_READY;
end
endcase
end
endmodule