From 5b8795a62154bc3106cf981aa063a74eb19fab3f Mon Sep 17 00:00:00 2001
From: Gyorgy Szombathelyi <gyurco@freemail.hu>
Date: Fri, 11 Dec 2020 01:08:21 +0100
Subject: [PATCH] MiST: simplify data_io a bit

---
 common/mist/data_io.v | 92 +++++++++++++++++++++----------------------
 1 file changed, 46 insertions(+), 46 deletions(-)

diff --git a/common/mist/data_io.v b/common/mist/data_io.v
index 9db519d5..1a8552a2 100644
--- a/common/mist/data_io.v
+++ b/common/mist/data_io.v
@@ -73,19 +73,17 @@ always@(negedge SPI_SCK or posedge SPI_SS2) begin : SPI_TRANSMITTER
 	if(SPI_SS2) begin
 		SPI_DO <= 1'bZ;
 	end else begin
-
-		if (cnt == 15) dout_r <= ioctl_din;
-		SPI_DO <= dout_r[~cnt[2:0]];
+		{SPI_DO, dout_r} <= (cnt == 15) ? {dout_r[7], ioctl_din} : {dout_r, 1'b0};
 	end
 end
 
-reg  [7:0] cmd;
 reg  [3:0] cnt;
-reg  [5:0] bytecnt;
 
 always@(posedge SPI_SCK, posedge SPI_SS2) begin : SPI_RECEIVER
 	reg  [6:0] sbuf;
 	reg [24:0] addr;
+	reg  [7:0] cmd;
+	reg  [5:0] bytecnt;
 
 	if(SPI_SS2) begin
 		bytecnt <= 0;
@@ -102,52 +100,53 @@ always@(posedge SPI_SCK, posedge SPI_SS2) begin : SPI_RECEIVER
 		// finished command byte
 		if(cnt == 7) cmd <= {sbuf, SPI_DI};
 
-		// prepare/end transmission
-		if((cmd == DIO_FILE_TX) && (cnt == 15)) begin
-			// prepare
-			if(SPI_DI) begin
-				addr_reset <= ~addr_reset;
-				downloading_reg <= 1;
-			end else begin
-				downloading_reg <= 0;
+		if(cnt == 15) begin
+			case (cmd)
+			// prepare/end transmission
+			DIO_FILE_TX: begin
+				// prepare
+				if(SPI_DI) begin
+					addr_reset <= ~addr_reset;
+					downloading_reg <= 1;
+				end else begin
+					downloading_reg <= 0;
+				end
 			end
-		end
 
-		if((cmd == DIO_FILE_RX) && (cnt == 15)) begin
-			// prepare
-			if(SPI_DI) begin
-				addr_reset <= ~addr_reset;
-				uploading_reg <= 1;
-			end else begin
-				uploading_reg <= 0;
+			DIO_FILE_RX: begin
+				// prepare
+				if(SPI_DI) begin
+					addr_reset <= ~addr_reset;
+					uploading_reg <= 1;
+				end else begin
+					uploading_reg <= 0;
+				end
 			end
-		end
 
-		// command 0x54: UIO_FILE_TX
-		if((cmd == DIO_FILE_TX_DAT) && (cnt == 15)) begin
-			data_w <= {sbuf, SPI_DI};
-			rclk <= ~rclk;
-		end
+			// command 0x57: DIO_FILE_RX_DAT
+			// command 0x54: DIO_FILE_TX_DAT
+			DIO_FILE_RX_DAT,
+			DIO_FILE_TX_DAT: begin
+				data_w <= {sbuf, SPI_DI};
+				rclk <= ~rclk;
+			end
 
-		// command 0x57: UIO_FILE_RX
-		if((cmd == DIO_FILE_RX_DAT) && (cnt == 15)) begin
-			rclk <= ~rclk;
-		end
+			// expose file (menu) index
+			DIO_FILE_INDEX: ioctl_index <= {sbuf, SPI_DI};
 
-		// expose file (menu) index
-		if((cmd == DIO_FILE_INDEX) && (cnt == 15)) ioctl_index <= {sbuf, SPI_DI};
-
-		// receiving FAT directory entry (mist-firmware/fat.h - DIRENTRY)
-		if((cmd == DIO_FILE_INFO) && (cnt == 15)) begin
-			bytecnt <= bytecnt + 1'd1;
-			case (bytecnt)
-				8'h08: ioctl_fileext[23:16]  <= {sbuf, SPI_DI};
-				8'h09: ioctl_fileext[15: 8]  <= {sbuf, SPI_DI};
-				8'h0A: ioctl_fileext[ 7: 0]  <= {sbuf, SPI_DI};
-				8'h1C: ioctl_filesize[ 7: 0] <= {sbuf, SPI_DI};
-				8'h1D: ioctl_filesize[15: 8] <= {sbuf, SPI_DI};
-				8'h1E: ioctl_filesize[23:16] <= {sbuf, SPI_DI};
-				8'h1F: ioctl_filesize[31:24] <= {sbuf, SPI_DI};
+			// receiving FAT directory entry (mist-firmware/fat.h - DIRENTRY)
+			DIO_FILE_INFO: begin
+				bytecnt <= bytecnt + 1'd1;
+				case (bytecnt)
+					8'h08: ioctl_fileext[23:16]  <= {sbuf, SPI_DI};
+					8'h09: ioctl_fileext[15: 8]  <= {sbuf, SPI_DI};
+					8'h0A: ioctl_fileext[ 7: 0]  <= {sbuf, SPI_DI};
+					8'h1C: ioctl_filesize[ 7: 0] <= {sbuf, SPI_DI};
+					8'h1D: ioctl_filesize[15: 8] <= {sbuf, SPI_DI};
+					8'h1E: ioctl_filesize[23:16] <= {sbuf, SPI_DI};
+					8'h1F: ioctl_filesize[31:24] <= {sbuf, SPI_DI};
+				endcase
+			end
 			endcase
 		end
 	end
@@ -244,8 +243,9 @@ always@(posedge clk_sys) begin : DATA_OUT
 	// detect new byte from the SPI receiver
 	if (rclkD ^ rclkD2) begin
 		wr_int <= downloading_reg;
-		if (uploading_reg) rd_int <= uploading_reg;
+		rd_int <= uploading_reg;
 	end
+	// direct transfer receiver
 	if (rclk2D ^ rclk2D2 && filepos != ioctl_filesize) begin
 		filepos <= filepos + 1'd1;
 		wr_int_direct <= 1;