From 07193819972aed16e8474913dbbbee5e01570e58 Mon Sep 17 00:00:00 2001
From: Olof Kindgren <olof.kindgren@gmail.com>
Date: Sat, 1 Jan 2022 17:15:00 +0100
Subject: [PATCH] Add ViDBo support

---
 bench/servant_tb_vidbo.cpp | 163 +++++++++++++++++++++++++++++++++++++
 servant.core               |   4 +-
 2 files changed, 166 insertions(+), 1 deletion(-)
 create mode 100644 bench/servant_tb_vidbo.cpp

diff --git a/bench/servant_tb_vidbo.cpp b/bench/servant_tb_vidbo.cpp
new file mode 100644
index 0000000..d0a8322
--- /dev/null
+++ b/bench/servant_tb_vidbo.cpp
@@ -0,0 +1,163 @@
+#include <stdint.h>
+#include <signal.h>
+
+#include "verilated_vcd_c.h"
+#include "Vservant_sim.h"
+
+#include "vidbo.h"
+
+using namespace std;
+
+static bool done;
+
+vluint64_t main_time = 0;       // Current simulation time
+// This is a 64-bit integer to reduce wrap over issues and
+// allow modulus.  You can also use a double, if you wish.
+
+double sc_time_stamp () {       // Called by $time in Verilog
+  return main_time;           // converts to double, to match
+  // what SystemC does
+}
+
+void INThandler(int signal)
+{
+  printf("\nCaught ctrl-c\n");
+  done = true;
+}
+
+typedef struct {
+  bool last_value;
+} gpio_context_t;
+
+void do_gpio(gpio_context_t *context, bool gpio) {
+  if (context->last_value != gpio) {
+    context->last_value = gpio;
+    printf("%lu output q is %s\n", main_time, gpio ? "ON" : "OFF");
+  }
+}
+
+typedef struct {
+  uint8_t state;
+  char ch;
+  uint32_t baud_t;
+  vluint64_t last_update;
+} uart_context_t;
+
+void uart_init(uart_context_t *context, uint32_t baud_rate) {
+  context->baud_t = 1000*1000*1000/baud_rate;
+  context->state = 0;
+}
+
+bool do_uart(uart_context_t *context, bool rx) {
+  if (context->state == 0) {
+    if (rx)
+      context->state++;
+  }
+  else if (context->state == 1) {
+    if (!rx) {
+      context->last_update = main_time + context->baud_t/2;
+      context->state++;
+    }
+  }
+  else if(context->state == 2) {
+    if (main_time > context->last_update) {
+      context->last_update += context->baud_t;
+      context->ch = 0;
+      context->state++;
+    }
+  }
+  else if (context->state < 11) {
+    if (main_time > context->last_update) {
+      context->last_update += context->baud_t;
+      context->ch |= rx << (context->state-3);
+      context->state++;
+    }
+  }
+  else {
+    if (main_time > context->last_update) {
+      context->last_update += context->baud_t;
+      context->state=1;
+      return true;
+    }
+  }
+  return false;
+}
+
+int main(int argc, char **argv, char **env)
+{
+  int baud_rate = 0;
+
+  gpio_context_t gpio_context;
+  uart_context_t uart_context;
+
+  vidbo_context_t vidbo_context;
+  vidbo_init(&vidbo_context, 8081);
+  int poll_vidbo = 0;
+
+  Verilated::commandArgs(argc, argv);
+
+  Vservant_sim* top = new Vservant_sim;
+
+  const char *arg = Verilated::commandArgsPlusMatch("uart_baudrate=");
+  if (arg[0]) {
+    baud_rate = atoi(arg+15);
+    if (baud_rate) {
+      uart_init(&uart_context, baud_rate);
+    }
+  }
+
+  VerilatedVcdC * tfp = 0;
+  const char *vcd = Verilated::commandArgsPlusMatch("vcd=");
+  if (vcd[0]) {
+    Verilated::traceEverOn(true);
+    tfp = new VerilatedVcdC;
+    top->trace (tfp, 99);
+    tfp->open ("trace.vcd");
+  }
+
+  signal(SIGINT, INThandler);
+
+  vluint64_t timeout = 0;
+  const char *arg_timeout = Verilated::commandArgsPlusMatch("timeout=");
+  if (arg_timeout[0])
+    timeout = atoi(arg_timeout+9);
+
+  vluint64_t vcd_start = 0;
+  const char *arg_vcd_start = Verilated::commandArgsPlusMatch("vcd_start=");
+  if (arg_vcd_start[0])
+    vcd_start = atoi(arg_vcd_start+11);
+
+  bool dump = false;
+  top->wb_clk = 1;
+  bool q = top->q;
+  while (!(done || Verilated::gotFinish())) {
+    if (tfp && !dump && (main_time > vcd_start)) {
+      dump = true;
+    }
+    top->wb_rst = main_time < 100;
+    top->eval();
+    if (dump)
+      tfp->dump(main_time);
+    if (baud_rate) {
+      if (do_uart(&uart_context, top->q))
+	vidbo_send(&vidbo_context, main_time, "serial", "uart", uart_context.ch);
+    }
+      if (top->q != gpio_context.last_value) {
+	vidbo_send(&vidbo_context, main_time, "gpio", "LD0", (top->q) & 0x1);
+	gpio_context.last_value = top->q;
+      }
+    if (timeout && (main_time >= timeout)) {
+      printf("Timeout: Exiting at time %lu\n", main_time);
+      done = true;
+    }
+
+    if (!(poll_vidbo++ % 100000)) vidbo_recv(&vidbo_context, 0);
+
+    top->wb_clk = !top->wb_clk;
+    main_time+=31.25;
+
+  }
+  if (tfp)
+    tfp->close();
+  exit(0);
+}
diff --git a/servant.core b/servant.core
index 1884773..2df904e 100644
--- a/servant.core
+++ b/servant.core
@@ -25,8 +25,10 @@ filesets:
   verilator_tb:
     files:
       - bench/servant_sim.v
-      - bench/servant_tb.cpp : {file_type : cppSource}
+      - "vidbo? (bench/servant_tb_vidbo.cpp)" : {file_type : cppSource}
+      - "!vidbo? (bench/servant_tb.cpp)" : {file_type : cppSource}
     file_type : verilogSource
+    depend : ["vidbo? (vidbo)"]
 
   soc:
     files: