From 8b188d47eab923fb152eae475c86b378d0d5ebee Mon Sep 17 00:00:00 2001
From: Alejandro Soto <alejandro@34project.org>
Date: Tue, 14 Nov 2023 07:00:11 -0600
Subject: rtl/gfx: implement memory interface

---
 rtl/gfx/gfx_mem.sv | 70 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 70 insertions(+)
 create mode 100644 rtl/gfx/gfx_mem.sv

(limited to 'rtl/gfx/gfx_mem.sv')

diff --git a/rtl/gfx/gfx_mem.sv b/rtl/gfx/gfx_mem.sv
new file mode 100644
index 0000000..4b671be
--- /dev/null
+++ b/rtl/gfx/gfx_mem.sv
@@ -0,0 +1,70 @@
+`include "gfx/gfx_defs.sv"
+
+module gfx_mem
+(
+	input  logic      clk,
+	                  rst_n,
+
+	input  logic      mem_waitrequest,
+	                  mem_readdatavalid,
+	input  mem_word   mem_readdata,
+	output mem_addr   mem_address,
+	output logic      mem_read,
+	                  mem_write,
+	output mem_word   mem_writedata,
+
+	input  logic      rop_write,
+	input  mem_word   rop_writedata,
+	input  half_coord rop_address,
+	output logic      rop_waitrequest,
+
+	input  logic      fb_read,
+	input  half_coord fb_address,
+	output logic      fb_waitrequest,
+	                  fb_readdatavalid,
+	output mem_word   fb_readdata
+);
+
+	// Esto está mal, hay que reescribirlo totalmente
+
+	logic lock, lock_rop, select_rop, wait_state;
+
+	assign fb_readdata = mem_readdata;
+	assign fb_readdatavalid = mem_readdatavalid;
+
+	assign mem_writedata = rop_writedata;
+
+	assign wait_state = (mem_read || mem_write) && mem_waitrequest;
+
+	always_comb begin
+		select_rop = !fb_read;
+
+		if (lock)
+			select_rop = lock_rop;
+
+		mem_read = 0;
+		mem_write = 0;
+		fb_waitrequest = 1;
+		rop_waitrequest = 1;
+
+		if (select_rop) begin
+			mem_write = rop_write;
+			mem_address = {6'd0, rop_address};
+
+			rop_waitrequest = mem_waitrequest;
+		end else begin
+			mem_read = fb_read;
+			mem_address = {6'd0, fb_address};
+
+			fb_waitrequest = mem_waitrequest;
+		end
+	end
+
+	always_ff @(posedge clk or negedge rst_n)
+		lock <= !rst_n ? 0 : wait_state;
+
+	always_ff @(posedge clk)
+		if (wait_state)
+			lock_rop <= select_rop;
+
+endmodule
-- 
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