From 1feb11642ab3f8d1cdc350ff3027bacf9434a4d7 Mon Sep 17 00:00:00 2001
From: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Date: Thu, 8 Apr 2021 14:11:50 +0100
Subject: [PATCH] remove cruft, add comments

---
 small_jtag_test/main.cpp | 76 +++++-----------------------------------
 1 file changed, 8 insertions(+), 68 deletions(-)

diff --git a/small_jtag_test/main.cpp b/small_jtag_test/main.cpp
index 5931804..e153d76 100644
--- a/small_jtag_test/main.cpp
+++ b/small_jtag_test/main.cpp
@@ -3,7 +3,7 @@
 #include <string.h>
 #include <unistd.h>
 #include <sys/select.h>
-#include <sys/types.h>          /* See NOTES */
+#include <sys/types.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>
@@ -68,77 +68,17 @@ int get_connection()
     connfd = accept(listenfd, (struct sockaddr*)NULL, NULL);
     close(listenfd);
 
-    setsockopt(connfd, IPPROTO_TCP, TCP_NODELAY, (char *) &flag, sizeof(int)); 
+    setsockopt(connfd, IPPROTO_TCP, TCP_NODELAY, (char *) &flag, sizeof(int));
     return connfd;
 }
 
-/*
-
-static void accept_conn_cb(struct evconnlistener *listener, evutil_socket_t fd, struct sockaddr *address, int socklen,  void *ctx)
-{
-  struct session_s *s = (struct session_s*)ctx;
-  struct timeval tv = {1, 0};
-
-  s->fd = fd;
-  s->ev = event_new(base, fd, EV_READ | EV_PERSIST , event_handler, s);
-  event_add(s->ev, &tv);
-}
-
-static int jtagremote_new(void **sess, char *args)
-{
-  int ret = RC_OK;
-  struct session_s *s = NULL;
-  char *cport = NULL;
-  int port;
-  struct evconnlistener *listener;
-  struct sockaddr_in sin;
-
-  if(!sess) {
-    ret = RC_INVARG;
-    goto out;
-  }
-
-  ret = litex_sim_module_get_args(args, "port", &cport);
-  if(RC_OK != ret)
-    goto out;
-
-  printf("Found port %s\n", cport);
-  sscanf(cport, "%d", &port);
-  free(cport);
-  if(!port) {
-    ret = RC_ERROR;
-    fprintf(stderr, "Invalid port selected!\n");
-    goto out;
-  }
-
-  s=(struct session_s*)malloc(sizeof(struct session_s));
-  if(!s) {
-    ret = RC_NOENMEM;
-    goto out;
-  }
-  memset(s, 0, sizeof(struct session_s));
-
-  memset(&sin, 0, sizeof(sin));
-  sin.sin_family = AF_INET;
-  sin.sin_addr.s_addr = htonl(0);
-  sin.sin_port = htons(port);
-  listener = evconnlistener_new_bind(base, accept_conn_cb, s,  LEV_OPT_CLOSE_ON_FREE|LEV_OPT_REUSEABLE, -1, (struct sockaddr*)&sin, sizeof(sin));
-  if (!listener) {
-    ret=RC_ERROR;
-    eprintf("Can't bind port %d\n!\n", port);
-    goto out;
-  }
-  evconnlistener_set_error_cb(listener, accept_error_cb);
-
-out:
-  *sess=(void*)s;
-  return ret;
-}
-
-*/
-
 } // extern "C"
 
+/* main function which polls the socket and talks openocd jtagremote protocol.
+   dead simple: incoming number 0-7 sets TCK, TMS and TDK.  request "R"
+   indicates that receiver wants to know the status of TDO.
+   "Q" means "quit socket".
+*/
 void read_openocd_jtagremote(cxxrtl_design::p_add &top, int sock)
 {
     char c;
@@ -184,7 +124,7 @@ int main()
         /* read and process incoming jtag */
         read_openocd_jtagremote(top, sock);
 
-        // check that the output is correct
+        // quick check that the output is correct (it's an adder: go figure)
         /*
         top.p_a.set<uint8_t>(5);
         top.p_b.set<uint8_t>(3);
-- 
2.30.2