Merge branch 'picosoc'

11 files changed, 225 insertions, 153 deletions

diff --git a/picosoc/.gitignore b/picosoc/.gitignore
index ab0e16e..9ec714d 100644
--- a/picosoc/.gitignore
+++ b/picosoc/.gitignore
@@ -3,7 +3,6 @@
 /spiflash_tb.vcd
 /spiflash_tb.vvp
 /firmware.elf
-/firmware_up.elf
 /firmware.hex
 /firmware.bin
 /hx8kdemo.asc
diff --git a/picosoc/Makefile b/picosoc/Makefile
index 49dc126..1a6ac94 100644
--- a/picosoc/Makefile
+++ b/picosoc/Makefile
@@ -19,6 +19,9 @@ hx8kprog: hx8kdemo.bin firmware.bin
 	iceprog hx8kdemo.bin
 	iceprog -o 1M firmware.bin
 
+hx8kprog_fw: firmware.bin
+	iceprog -o 1M firmware.bin
+
 hx8ksim: hx8kdemo_tb.vvp firmware.hex
 	vvp -N $<
 
@@ -46,25 +49,22 @@ hx8kdemo.bin: hx8kdemo.asc
 
 # ---- Example Firmware ----
 
-firmware.elf: sections.lds firmware.S
-	riscv32-unknown-elf-gcc -Wl,-Bstatic,-T,sections.lds,--strip-debug -ffreestanding -nostdlib -o firmware.elf firmware.S
-
-firmware_up.elf: firmware.elf
-	riscv32-unknown-elf-objcopy --change-addresses 0x100000 firmware.elf firmware_up.elf
+firmware.elf: sections.lds start.s firmware.c
+	riscv32-unknown-elf-gcc -Wl,-Bstatic,-T,sections.lds,--strip-debug -ffreestanding -nostdlib -o firmware.elf start.s firmware.c
 
-firmware.hex: firmware_up.elf
-	riscv32-unknown-elf-objcopy -O verilog firmware_up.elf firmware.hex
+firmware.hex: firmware.elf
+	riscv32-unknown-elf-objcopy -O verilog firmware.elf /dev/stdout | sed -e '2,65537 d;' > firmware.hex
 
 firmware.bin: firmware.elf
-	riscv32-unknown-elf-objcopy -O binary firmware.elf firmware.bin
+	riscv32-unknown-elf-objcopy -O binary firmware.elf /dev/stdout | tail -c +1048577 > firmware.bin
 
 # ---- Clean ----
 
 clean:
 	rm -f testbench.vvp testbench.vcd spiflash_tb.vvp spiflash_tb.vcd
-	rm -f firmware.elf firmware_up.elf firmware.hex firmware.bin
+	rm -f firmware.elf firmware.hex firmware.bin
 	rm -f hx8kdemo.blif hx8kdemo.log hx8kdemo.asc hx8kdemo.rpt hx8kdemo.bin
 	rm -f hx8kdemo_syn.v hx8kdemo_syn_tb.vvp hx8kdemo_tb.vvp
 
-.PHONY: testbench spiflash_tb hx8kprog hx8ksim hx8ksynsim clean
+.PHONY: testbench spiflash_tb hx8kprog hx8kprog_fw hx8ksim hx8ksynsim clean
 
diff --git a/picosoc/README.md b/picosoc/README.md
index 77ea038..2fd558c 100644
--- a/picosoc/README.md
+++ b/picosoc/README.md
@@ -38,6 +38,9 @@ and upload them to a connected iCE40-HX8K Breakout Board.
 | 0x02000008 .. 0x0200000B | UART Send/Recv Data Register            |
 | 0x03000000 .. 0xFFFFFFFF | Memory mapped user peripherals          |
 
+The addresses in the internal SRAM region beyond the end of the physical
+SRAM map to the corresponding addresses in serial flash.
+
 Reading from the UART Send/Recv Data Register will return the last received
 byte, or -1 (all 32 bits set) when the receive buffer is empty.
 
diff --git a/picosoc/firmware.S b/picosoc/firmware.S
deleted file mode 100644
index efd49b4..0000000
--- a/picosoc/firmware.S
+++ /dev/null
@@ -1,126 +0,0 @@
-// write RAM code (a sequence of nops followed by ret)
-li      x5,0x00000013   // nop
-sw      x5,4(x0)
-sw      x5,8(x0)
-sw      x5,12(x0)
-sw      x5,16(x0)
-sw      x5,20(x0)
-sw      x5,24(x0)
-sw      x5,28(x0)
-sw      x5,32(x0)
-sw      x5,36(x0)
-sw      x5,40(x0)
-sw      x5,44(x0)
-sw      x5,48(x0)
-sw      x5,52(x0)
-sw      x5,56(x0)
-sw      x5,60(x0)
-sw      x5,64(x0)
-sw      x5,68(x0)
-sw      x5,72(x0)
-sw      x5,76(x0)
-sw      x5,80(x0)
-sw      x5,84(x0)
-sw      x5,88(x0)
-sw      x5,92(x0)
-sw      x5,96(x0)
-sw      x5,100(x0)
-sw      x5,104(x0)
-sw      x5,108(x0)
-sw      x5,112(x0)
-sw      x5,116(x0)
-sw      x5,120(x0)
-sw      x5,124(x0)
-sw      x5,128(x0)
-sw      x5,132(x0)
-sw      x5,136(x0)
-sw      x5,140(x0)
-sw      x5,144(x0)
-sw      x5,148(x0)
-sw      x5,152(x0)
-sw      x5,156(x0)
-sw      x5,160(x0)
-sw      x5,164(x0)
-sw      x5,168(x0)
-sw      x5,172(x0)
-sw      x5,176(x0)
-sw      x5,180(x0)
-sw      x5,184(x0)
-sw      x5,188(x0)
-sw      x5,192(x0)
-li      x5,0x00008067   // ret
-sw      x5,196(x0)
-
-// write a few chars to UART
-li      x5,0x02000004
-li      x6,104
-sw      x6,0(x5)
-li      x5,0x02000008
-li      x6,'H'
-sw      x6,0(x5)
-li      x6,'e'
-sw      x6,0(x5)
-li      x6,'l'
-sw      x6,0(x5)
-li      x6,'l'
-sw      x6,0(x5)
-li      x6,'o'
-sw      x6,0(x5)
-li      x6,' '
-sw      x6,0(x5)
-li      x6,'W'
-sw      x6,0(x5)
-li      x6,'o'
-sw      x6,0(x5)
-li      x6,'r'
-sw      x6,0(x5)
-li      x6,'l'
-sw      x6,0(x5)
-li      x6,'d'
-sw      x6,0(x5)
-li      x6,'!'
-sw      x6,0(x5)
-li      x6,'\r'
-sw      x6,0(x5)
-li      x6,'\n'
-sw      x6,0(x5)
-
-#if 0
-// switch spimemio to continous qspi ddr mode
-li      x5,0x02000000
-li      x6,0x80000071
-sw      x6,0(x5)
-#endif
-
-// setup gpio address in x5
-li      x5,0x03000000
-sw      x0,0(x5)
-
-// initial entry point into RAM code
-li      x3,4
-
-// initialize RAM counter
-sw      x0,0(x0)
-
-// start of loop. remember this address
-auipc   x4,0
-
-// execute RAM code, come back here
-jalr    x3
-
-// load counter and increment
-lw      x6,0(x0)
-addi    x6,x6,1
-
-// store counter and update gpios
-sw      x6,0(x5)
-sw      x6,0(x0)
-
-// calculate new entry point into RAM code
-slli    x3,x6,2
-andi    x3,x3,127
-addi    x3,x3,32
-
-// execute RAM code, come back to start of loop
-mv      x1,x4
-jr      x3
diff --git a/picosoc/firmware.c b/picosoc/firmware.c
new file mode 100644
index 0000000..660ef56
--- /dev/null
+++ b/picosoc/firmware.c
@@ -0,0 +1,105 @@
+#include <stdint.h>
+
+#define reg_spictrl (*(volatile uint32_t*)0x02000000)
+#define reg_uart_clkdiv (*(volatile uint32_t*)0x02000004)
+#define reg_uart_data (*(volatile uint32_t*)0x02000008)
+#define reg_leds (*(volatile uint32_t*)0x03000000)
+
+void print(const char *p)
+{
+	while (*p) {
+		if (*p == '\n')
+			reg_uart_data = '\r';
+		reg_uart_data = *(p++);
+	}
+}
+
+char getchar_prompt(char *prompt)
+{
+	int32_t c = -1;
+
+	uint32_t cycles_begin, cycles_now, cycles;
+	__asm__ volatile ("rdcycle %0" : "=r"(cycles_begin));
+
+	if (prompt)
+		print(prompt);
+
+	reg_leds = ~0;
+	while (c == -1) {
+		__asm__ volatile ("rdcycle %0" : "=r"(cycles_now));
+		cycles = cycles_now - cycles_begin;
+		if (cycles > 12000000) {
+			if (prompt)
+				print(prompt);
+			cycles_begin = cycles_now;
+			reg_leds = ~reg_leds;
+		}
+		c = reg_uart_data;
+	}
+	reg_leds = 0;
+	return c;
+}
+
+char getchar()
+{
+	return getchar_prompt(0);
+}
+
+// --------------------------------------------------------
+
+extern uint32_t cmd_read_spi_flash_id_worker_begin;
+extern uint32_t cmd_read_spi_flash_id_worker_end;
+
+void cmd_read_spi_flash_id()
+{
+	uint32_t *src_ptr = &cmd_read_spi_flash_id_worker_begin;
+	uint32_t *dst_ptr = (uint32_t*)0;
+
+	while (src_ptr != &cmd_read_spi_flash_id_worker_end)
+		*(dst_ptr++) = *(src_ptr++);
+
+	((void(*)())0)();
+}
+
+// --------------------------------------------------------
+
+void main()
+{
+	reg_uart_clkdiv = 104;
+	while (getchar_prompt("Press ENTER to continue..\n") != '\r') { /* wait */ }
+
+	print("\n");
+	print("  ____  _          ____         ____\n");
+	print(" |  _ \\(_) ___ ___/ ___|  ___  / ___|\n");
+	print(" | |_) | |/ __/ _ \\___ \\ / _ \\| |\n");
+	print(" |  __/| | (_| (_) |__) | (_) | |___\n");
+	print(" |_|   |_|\\___\\___/____/ \\___/ \\____|\n");
+
+	while (1)
+	{
+		print("\n");
+		print("\n");
+		print("Select an action:\n");
+		print("\n");
+		print("   [1] Read SPI Flash ID\n");
+		print("\n");
+
+		for (int rep = 10; rep > 0; rep--)
+		{
+			print("Command> ");
+			char cmd = getchar();
+			if (cmd > 32 && cmd < 127)
+				reg_uart_data = cmd;
+			print("\n");
+
+			switch (cmd)
+			{
+			case '1':
+				cmd_read_spi_flash_id();
+				rep = 0;
+				break;
+			}
+		}
+	}
+}
+
diff --git a/picosoc/hx8kdemo.pcf b/picosoc/hx8kdemo.pcf
index 8e082f8..418bae8 100644
--- a/picosoc/hx8kdemo.pcf
+++ b/picosoc/hx8kdemo.pcf
@@ -7,12 +7,28 @@ set_io flash_csb R12
 set_io flash_clk R11
 set_io flash_io0 P12
 set_io flash_io1 P11
-set_io flash_io2 T9  # center on J3
-set_io flash_io3 P8  # center on J3
+
+# for QSPI mode the flash chip on the iCE40-HX8K Breakout Board
+# must be replaced with one that supports QSPI and the IO2 and IO3
+# pins must be soldered to T9 and P8 (center on J3)
+set_io flash_io2 T9
+set_io flash_io3 P8
 
 set_io ser_tx B12
 set_io ser_rx B10
 
+# left on J3
+set_io debug_ser_tx T1
+set_io debug_ser_rx R3
+
+# right on J3
+set_io debug_flash_csb T15
+set_io debug_flash_clk R16
+set_io debug_flash_io0 N12
+set_io debug_flash_io1 P13
+set_io debug_flash_io2 T13
+set_io debug_flash_io3 T14
+
 set_io leds[7] B5  # D9
 set_io leds[6] B4  # D8
 set_io leds[5] A2  # D7
diff --git a/picosoc/hx8kdemo.v b/picosoc/hx8kdemo.v
index 97f97b1..9cf6605 100644
--- a/picosoc/hx8kdemo.v
+++ b/picosoc/hx8kdemo.v
@@ -30,7 +30,17 @@ module hx8kdemo (
 	inout  flash_io0,
 	inout  flash_io1,
 	inout  flash_io2,
-	inout  flash_io3
+	inout  flash_io3,
+
+	output debug_ser_tx,
+	output debug_ser_rx,
+
+	output debug_flash_csb,
+	output debug_flash_clk,
+	output debug_flash_io0,
+	output debug_flash_io1,
+	output debug_flash_io2,
+	output debug_flash_io3
 );
 	reg [5:0] reset_cnt = 0;
 	wire resetn = &reset_cnt;
@@ -62,14 +72,11 @@ module hx8kdemo (
 	reg  [31:0] iomem_rdata;
 
 	reg [31:0] gpio;
-	reg [4:0] gpio_shr;
-
-	assign leds = gpio >> gpio_shr;
+	assign leds = gpio;
 
 	always @(posedge clk) begin
 		if (!resetn) begin
 			gpio <= 0;
-			gpio_shr <= 0;
 		end else begin
 			iomem_ready <= 0;
 			if (iomem_valid && !iomem_ready && iomem_addr[31:24] == 8'h 03) begin
@@ -80,9 +87,6 @@ module hx8kdemo (
 				if (iomem_wstrb[2]) gpio[23:16] <= iomem_wdata[23:16];
 				if (iomem_wstrb[3]) gpio[31:24] <= iomem_wdata[31:24];
 			end
-			if (&leds && gpio_shr < 10) begin
-				gpio_shr <= gpio_shr + 1;
-			end
 		end
 	end
 
@@ -118,4 +122,14 @@ module hx8kdemo (
 		.iomem_wdata  (iomem_wdata ),
 		.iomem_rdata  (iomem_rdata )
 	);
+
+	assign debug_ser_tx = ser_tx;
+	assign debug_ser_rx = ser_rx;
+
+	assign debug_flash_csb = flash_csb;
+	assign debug_flash_clk = flash_clk;
+	assign debug_flash_io0 = flash_io0_di;
+	assign debug_flash_io1 = flash_io1_di;
+	assign debug_flash_io2 = flash_io2_di;
+	assign debug_flash_io3 = flash_io3_di;
 endmodule
diff --git a/picosoc/hx8kdemo_tb.v b/picosoc/hx8kdemo_tb.v
index ffb292f..585c8dd 100644
--- a/picosoc/hx8kdemo_tb.v
+++ b/picosoc/hx8kdemo_tb.v
@@ -41,7 +41,7 @@ module testbench;
 	wire flash_io3;
 
 	always @(leds) begin
-		$display("%b", leds);
+		#1 $display("%b", leds);
 	end
 
 	hx8kdemo uut (
diff --git a/picosoc/picosoc.v b/picosoc/picosoc.v
index a648b0e..116b237 100644
--- a/picosoc/picosoc.v
+++ b/picosoc/picosoc.v
@@ -51,7 +51,7 @@ module picosoc (
 );
 	parameter integer MEM_WORDS = 256;
 	parameter [31:0] STACKADDR = (4*MEM_WORDS);       // end of memory
-	parameter [31:0] PROGADDR_RESET = 32'h 0110_0000; // 1 MB into flash
+	parameter [31:0] PROGADDR_RESET = 32'h 0010_0000; // 1 MB into flash
 
 	wire mem_valid;
 	wire mem_instr;
@@ -87,7 +87,7 @@ module picosoc (
 
 	assign mem_rdata = (iomem_valid && iomem_ready) ? iomem_rdata : spimem_ready ? spimem_rdata : ram_ready ? ram_rdata :
 			spimemio_cfgreg_sel ? spimemio_cfgreg_do : simpleuart_reg_div_sel ? simpleuart_reg_div_do :
-			simpleuart_reg_dat_sel ? simpleuart_reg_dat_do : 32'h xxxx_xxxx;
+			simpleuart_reg_dat_sel ? simpleuart_reg_dat_do : 32'h 0000_0000;
 
 	picorv32 #(
 		.STACKADDR(STACKADDR),
@@ -107,7 +107,7 @@ module picosoc (
 	spimemio spimemio (
 		.clk    (clk),
 		.resetn (resetn),
-		.valid  (mem_valid && mem_addr[31:24] == 8'h 01),
+		.valid  (mem_valid && mem_addr >= 4*MEM_WORDS && mem_addr < 32'h 0200_0000),
 		.ready  (spimem_ready),
 		.addr   (mem_addr[23:0]),
 		.rdata  (spimem_rdata),
@@ -157,7 +157,7 @@ module picosoc (
 
 	always @(posedge clk) begin
 		ram_ready <= 0;
-		if (mem_valid && !mem_ready && mem_addr[31:24] == 8'h 00) begin
+		if (mem_valid && !mem_ready && mem_addr < 4*MEM_WORDS) begin
 			ram_ready <= 1;
 			ram_rdata <= memory[mem_addr >> 2];
 			if (mem_wstrb[0]) memory[mem_addr >> 2][ 7: 0] <= mem_wdata[ 7: 0];
diff --git a/picosoc/sections.lds b/picosoc/sections.lds
index 5c92529..1fe7919 100644
--- a/picosoc/sections.lds
+++ b/picosoc/sections.lds
@@ -1,6 +1,6 @@
 SECTIONS {
 	.memory : {
-		. = 0x000000;
+		. = 0x100000;
 		start*(.text);
 		*(.text);
 		*(*);
diff --git a/picosoc/start.s b/picosoc/start.s
new file mode 100644
index 0000000..47312d8
--- /dev/null
+++ b/picosoc/start.s
@@ -0,0 +1,61 @@
+.section .text
+
+start:
+addi x1, zero, 0
+addi x2, zero, 0
+addi x3, zero, 0
+addi x4, zero, 0
+addi x5, zero, 0
+addi x6, zero, 0
+addi x7, zero, 0
+addi x8, zero, 0
+addi x9, zero, 0
+addi x10, zero, 0
+addi x11, zero, 0
+addi x12, zero, 0
+addi x13, zero, 0
+addi x14, zero, 0
+addi x15, zero, 0
+addi x16, zero, 0
+addi x17, zero, 0
+addi x18, zero, 0
+addi x19, zero, 0
+addi x20, zero, 0
+addi x21, zero, 0
+addi x22, zero, 0
+addi x23, zero, 0
+addi x24, zero, 0
+addi x25, zero, 0
+addi x26, zero, 0
+addi x27, zero, 0
+addi x28, zero, 0
+addi x29, zero, 0
+addi x30, zero, 0
+addi x31, zero, 0
+
+li sp, 4*256
+call main
+j start
+
+.global cmd_read_spi_flash_id_worker_begin
+.global cmd_read_spi_flash_id_worker_end
+
+cmd_read_spi_flash_id_worker_begin:
+li t0,0x02000008
+li t1,'F'
+sw t1,0(t0)
+li t1,'I'
+sw t1,0(t0)
+li t1,'X'
+sw t1,0(t0)
+li t1,'M'
+sw t1,0(t0)
+li t1,'E'
+sw t1,0(t0)
+li t1,'\r'
+sw t1,0(t0)
+li t1,'\n'
+sw t1,0(t0)
+ret
+cmd_read_spi_flash_id_worker_end:
+