Add PicoSoC spimem Dual I/O support

3 files changed, 99 insertions, 22 deletions

diff --git a/picosoc/README.md b/picosoc/README.md
index c112835..aec6142 100644
--- a/picosoc/README.md
+++ b/picosoc/README.md
@@ -55,8 +55,8 @@ GPIO pins mapped to the 32 bit word at address 0x03000000.
 |  30:23 | Reserved (read 0)                                         |
 |     22 | DDR Enable bit (reset=0)                                  |
 |     21 | QSPI Enable bit (reset=0)                                 |
-|     20 | XIP Enable bit (reset=0)                                  |
-|  19:16 | Number of QSPI dummy cycles (reset=0)                     |
+|     20 | CRM Enable bit (reset=0)                                  |
+|  19:16 | Read latency (dummy) cycles (reset=0)                     |
 |  15:12 | Reserved (read 0)                                         |
 |   11:8 | IO Output enable bits in bit bang mode                    |
 |    7:6 | Reserved (read 0)                                         |
@@ -64,13 +64,15 @@ GPIO pins mapped to the 32 bit word at address 0x03000000.
 |      4 | Serial clock line in bit bang mode                        |
 |    3:0 | IO data bits in bit bang mode                             |
 
-The following settings for XIP/DDR/QSPI modes are valid:
-
-| XIP | DDR | QSPI | Read Command Byte     | Mode Byte |
-| :-: | :-: | :--: | :-------------------- | :-------: |
-|   0 |   0 |    0 | 03h Read              | N/A       |
-|   0 |   0 |    1 | EBh Quad I/O Read     | FFh       |
-|   1 |   0 |    1 | EBh Quad I/O Read     | A5h / FFh |
-|   0 |   1 |    1 | EDh DDR Quad I/O Read | FFh       |
-|   1 |   1 |    1 | EDh DDR Quad I/O Read | A5h / FFh |
+The following settings for CRM/DDR/QSPI modes are valid:
+
+| CRM | QSPI | DDR | Read Command Byte     | Mode Byte |
+| :-: | :--: | :-: | :-------------------- | :-------: |
+|   0 |    0 |   0 | 03h Read              | N/A       |
+|   0 |    0 |   1 | BBh Dual I/O Read     | FFh       |
+|   1 |    0 |   1 | BBh Dual I/O Read     | A5h       |
+|   0 |    1 |   0 | EBh Quad I/O Read     | FFh       |
+|   1 |    1 |   0 | EBh Quad I/O Read     | A5h       |
+|   0 |    1 |   1 | EDh DDR Quad I/O Read | FFh       |
+|   1 |    1 |   1 | EDh DDR Quad I/O Read | A5h       |
 
diff --git a/picosoc/spiflash.v b/picosoc/spiflash.v
index 18cd68d..63d21dc 100644
--- a/picosoc/spiflash.v
+++ b/picosoc/spiflash.v
@@ -26,7 +26,7 @@
 // updates output signals 1ns after the SPI clock edge.
 //
 // Supported commands:
-//    AB, B9, FF, 03, EB, ED
+//    AB, B9, FF, 03, BB, EB, ED
 //
 // Well written SPI flash data sheets:
 //    Cypress S25FL064L http://www.cypress.com/file/316661/download
@@ -60,10 +60,12 @@ module spiflash (
 	reg powered_up = 0;
 
 	localparam [3:0] mode_spi         = 1;
-	localparam [3:0] mode_qspi_rd     = 2;
-	localparam [3:0] mode_qspi_wr     = 3;
-	localparam [3:0] mode_qspi_ddr_rd = 4;
-	localparam [3:0] mode_qspi_ddr_wr = 5;
+	localparam [3:0] mode_dspi_rd     = 2;
+	localparam [3:0] mode_dspi_wr     = 3;
+	localparam [3:0] mode_qspi_rd     = 4;
+	localparam [3:0] mode_qspi_wr     = 5;
+	localparam [3:0] mode_qspi_ddr_rd = 6;
+	localparam [3:0] mode_qspi_ddr_wr = 7;
 
 	reg [3:0] mode = 0;
 	reg [3:0] next_mode = 0;
@@ -133,6 +135,31 @@ module spiflash (
 				end
 			end
 
+			if (powered_up && spi_cmd == 'h bb) begin
+				if (bytecount == 1)
+					mode = mode_dspi_rd;
+
+				if (bytecount == 2)
+					spi_addr[23:16] = buffer;
+
+				if (bytecount == 3)
+					spi_addr[15:8] = buffer;
+
+				if (bytecount == 4)
+					spi_addr[7:0] = buffer;
+
+				if (bytecount == 5) begin
+					xip_cmd = (buffer == 8'h a5) ? spi_cmd : 8'h 00;
+					mode = mode_dspi_wr;
+					dummycount = latency;
+				end
+
+				if (bytecount >= 5) begin
+					buffer = memory[spi_addr];
+					spi_addr = spi_addr + 1;
+				end
+			end
+
 			if (powered_up && spi_cmd == 'h eb) begin
 				if (bytecount == 1)
 					mode = mode_qspi_rd;
@@ -269,6 +296,20 @@ module spiflash (
 					io3_oe = 0;
 					io1_dout = buffer[7];
 				end
+				mode_dspi_rd: begin
+					io0_oe = 0;
+					io1_oe = 0;
+					io2_oe = 0;
+					io3_oe = 0;
+				end
+				mode_dspi_wr: begin
+					io0_oe = 1;
+					io1_oe = 1;
+					io2_oe = 0;
+					io3_oe = 0;
+					io0_dout = buffer[6];
+					io1_dout = buffer[7];
+				end
 				mode_qspi_rd: begin
 					io0_oe = 0;
 					io1_oe = 0;
@@ -332,6 +373,15 @@ module spiflash (
 						spi_action;
 					end
 				end
+				mode_dspi_rd, mode_dspi_wr: begin
+					buffer = {buffer, io1, io0};
+					bitcount = bitcount + 2;
+					if (bitcount == 8) begin
+						bitcount = 0;
+						bytecount = bytecount + 1;
+						spi_action;
+					end
+				end
 				mode_qspi_rd, mode_qspi_wr: begin
 					buffer = {buffer, io3, io2, io1, io0};
 					bitcount = bitcount + 4;
diff --git a/picosoc/spimemio.v b/picosoc/spimemio.v
index 311edcd..0bbf532 100644
--- a/picosoc/spimemio.v
+++ b/picosoc/spimemio.v
@@ -168,6 +168,9 @@ module spimemio (
 	assign flash_io2_do = config_en ? (config_ddr ? xfer_io2_90 : xfer_io2_do) : config_do[2];
 	assign flash_io3_do = config_en ? (config_ddr ? xfer_io3_90 : xfer_io3_do) : config_do[3];
 
+	wire xfer_dspi = din_ddr && !din_qspi;
+	wire xfer_ddr = din_ddr && din_qspi;
+
 	spimemio_xfer xfer (
 		.clk          (clk         ),
 		.resetn       (xfer_resetn ),
@@ -176,8 +179,9 @@ module spimemio (
 		.din_data     (din_data    ),
 		.din_tag      (din_tag     ),
 		.din_cont     (din_cont    ),
+		.din_dspi     (xfer_dspi   ),
 		.din_qspi     (din_qspi    ),
-		.din_ddr      (din_ddr     ),
+		.din_ddr      (xfer_ddr    ),
 		.din_rd       (din_rd      ),
 		.dout_valid   (dout_valid  ),
 		.dout_data    (dout_data   ),
@@ -266,6 +270,7 @@ module spimemio (
 					case ({config_ddr, config_qspi})
 						2'b11: din_data <= 8'h ED;
 						2'b01: din_data <= 8'h EB;
+						2'b10: din_data <= 8'h BB;
 						2'b00: din_data <= 8'h 03;
 					endcase
 					if (din_ready) begin
@@ -302,7 +307,7 @@ module spimemio (
 					if (din_ready) begin
 						din_valid <= 0;
 						din_data <= 0;
-						state <= config_qspi ? 8 : 9;
+						state <= config_qspi || config_ddr ? 8 : 9;
 					end
 				end
 				8: begin
@@ -378,6 +383,7 @@ module spimemio_xfer (
 	input      [7:0] din_data,
 	input      [3:0] din_tag,
 	input            din_cont,
+	input            din_dspi,
 	input            din_qspi,
 	input            din_ddr,
 	input            din_rd,
@@ -411,6 +417,7 @@ module spimemio_xfer (
 	reg [3:0] dummy_count;
 
 	reg xfer_cont;
+	reg xfer_dspi;
 	reg xfer_qspi;
 	reg xfer_ddr;
 	reg xfer_ddr_q;
@@ -454,8 +461,8 @@ module spimemio_xfer (
 		next_fetch = 0;
 
 		if (dummy_count == 0) begin
-			case ({xfer_ddr, xfer_qspi})
-				2'b 00: begin
+			casez ({xfer_ddr, xfer_qspi, xfer_dspi})
+				3'b 000: begin
 					flash_io0_oe = 1;
 					flash_io0_do = obuffer[7];
 
@@ -468,7 +475,7 @@ module spimemio_xfer (
 
 					next_fetch = (next_count == 0);
 				end
-				2'b 01: begin
+				3'b 01?: begin
 					flash_io0_oe = !xfer_rd;
 					flash_io1_oe = !xfer_rd;
 					flash_io2_oe = !xfer_rd;
@@ -488,7 +495,7 @@ module spimemio_xfer (
 
 					next_fetch = (next_count == 0);
 				end
-				2'b 11: begin
+				3'b 11?: begin
 					flash_io0_oe = !xfer_rd;
 					flash_io1_oe = !xfer_rd;
 					flash_io2_oe = !xfer_rd;
@@ -505,6 +512,22 @@ module spimemio_xfer (
 
 					next_fetch = (next_count == 0);
 				end
+				3'b ??1: begin
+					flash_io0_oe = !xfer_rd;
+					flash_io1_oe = !xfer_rd;
+
+					flash_io0_do = obuffer[6];
+					flash_io1_do = obuffer[7];
+
+					if (flash_clk) begin
+						next_obuffer = {obuffer[5:0], 2'b 00};
+						next_count = count - {|count, 1'b0};
+					end else begin
+						next_ibuffer = {ibuffer[5:0], flash_io1_di, flash_io0_di};
+					end
+
+					next_fetch = (next_count == 0);
+				end
 			endcase
 		end
 	end
@@ -519,6 +542,7 @@ module spimemio_xfer (
 			dummy_count <= 0;
 			xfer_tag <= 0;
 			xfer_cont <= 0;
+			xfer_dspi <= 0;
 			xfer_qspi <= 0;
 			xfer_ddr <= 0;
 			xfer_rd <= 0;
@@ -545,6 +569,7 @@ module spimemio_xfer (
 
 				xfer_tag <= din_tag;
 				xfer_cont <= din_cont;
+				xfer_dspi <= din_dspi;
 				xfer_qspi <= din_qspi;
 				xfer_ddr <= din_ddr;
 				xfer_rd <= din_rd;