riscv/remote_bitbang.cc

   1 #include <arpa/inet.h>
   2 #include <errno.h>
   3 #include <fcntl.h>
   4 #include <stdlib.h>
   5 #include <string.h>
   6 #include <unistd.h>
   7
   8 #include <algorithm>
   9 #include <cassert>
  10 #include <cstdio>
  11
  12 #include "remote_bitbang.h"
  13
  14 #if 1
  15 #  define D(x) x
  16 #else
  17 #  define D(x)
  18 #endif
  19
  20 /////////// remote_bitbang_t
  21
  22 remote_bitbang_t::remote_bitbang_t(uint16_t port, jtag_dtm_t *tap) :
  23   tap(tap),
  24   socket_fd(0),
  25   client_fd(0)
  26 {
  27   socket_fd = socket(AF_INET, SOCK_STREAM, 0);
  28   if (socket_fd == -1) {
  29     fprintf(stderr, "remote_bitbang failed to make socket: %s (%d)\n",
  30         strerror(errno), errno);
  31     abort();
  32   }
  33
  34   fcntl(socket_fd, F_SETFL, O_NONBLOCK);
  35   int reuseaddr = 1;
  36   if (setsockopt(socket_fd, SOL_SOCKET, SO_REUSEADDR, &reuseaddr,
  37         sizeof(int)) == -1) {
  38     fprintf(stderr, "remote_bitbang failed setsockopt: %s (%d)\n",
  39         strerror(errno), errno);
  40     abort();
  41   }
  42
  43   struct sockaddr_in addr;
  44   memset(&addr, 0, sizeof(addr));
  45   addr.sin_family = AF_INET;
  46   addr.sin_addr.s_addr = INADDR_ANY;
  47   addr.sin_port = htons(port);
  48
  49   if (bind(socket_fd, (struct sockaddr *) &addr, sizeof(addr)) == -1) {
  50     fprintf(stderr, "remote_bitbang failed to bind socket: %s (%d)\n",
  51         strerror(errno), errno);
  52     abort();
  53   }
  54
  55   if (listen(socket_fd, 1) == -1) {
  56     fprintf(stderr, "remote_bitbang failed to listen on socket: %s (%d)\n",
  57         strerror(errno), errno);
  58     abort();
  59   }
  60
  61   socklen_t addrlen = sizeof(addr);
  62   if (getsockname(socket_fd, (struct sockaddr *) &addr, &addrlen) == -1) {
  63     fprintf(stderr, "remote_bitbang getsockname failed: %s (%d)\n",
  64         strerror(errno), errno);
  65     abort();
  66   }
  67
  68   printf("Listening for remote bitbang connection on port %d.\n",
  69       ntohs(addr.sin_port));
  70   fflush(stdout);
  71 }
  72
  73 void remote_bitbang_t::accept()
  74 {
  75   client_fd = ::accept(socket_fd, NULL, NULL);
  76   if (client_fd == -1) {
  77     if (errno == EAGAIN) {
  78       // No client waiting to connect right now.
  79     } else {
  80       fprintf(stderr, "failed to accept on socket: %s (%d)\n", strerror(errno),
  81           errno);
  82       abort();
  83     }
  84   } else {
  85     fcntl(client_fd, F_SETFL, O_NONBLOCK);
  86   }
  87 }
  88
  89 void remote_bitbang_t::tick()
  90 {
  91   if (client_fd > 0) {
  92     execute_commands();
  93   } else {
  94     this->accept();
  95   }
  96 }
  97
  98 void remote_bitbang_t::execute_commands()
  99 {
 100   const unsigned buf_size = 64 * 1024;
 101   static char recv_buf[buf_size];
 102   static char send_buf[buf_size];
 103   unsigned total_received = 0;
 104   ssize_t bytes = read(client_fd, recv_buf, buf_size);
 105   bool quit = false;
 106   while (bytes > 0) {
 107     total_received += bytes;
 108     unsigned send_offset = 0;
 109     for (unsigned i = 0; i < bytes; i++) {
 110       uint8_t command = recv_buf[i];
 111
 112       switch (command) {
 113         case 'B': /* fprintf(stderr, "*BLINK*\n"); */ break;
 114         case 'b': /* fprintf(stderr, "_______\n"); */ break;
 115         case 'r': tap->reset(); break;
 116         case '0': tap->set_pins(0, 0, 0); break;
 117         case '1': tap->set_pins(0, 0, 1); break;
 118         case '2': tap->set_pins(0, 1, 0); break;
 119         case '3': tap->set_pins(0, 1, 1); break;
 120         case '4': tap->set_pins(1, 0, 0); break;
 121         case '5': tap->set_pins(1, 0, 1); break;
 122         case '6': tap->set_pins(1, 1, 0); break;
 123         case '7': tap->set_pins(1, 1, 1); break;
 124         case 'R': send_buf[send_offset++] = tap->tdo() ? '1' : '0'; break;
 125         case 'Q': quit = true; break;
 126         default:
 127                   fprintf(stderr, "remote_bitbang got unsupported command '%c'\n",
 128                       command);
 129       }
 130     }
 131     unsigned sent = 0;
 132     while (sent < send_offset) {
 133       bytes = write(client_fd, send_buf + sent, send_offset);
 134       if (bytes == -1) {
 135         fprintf(stderr, "failed to write to socket: %s (%d)\n", strerror(errno), errno);
 136         abort();
 137       }
 138       sent += bytes;
 139     }
 140
 141     if (total_received > buf_size || quit) {
 142       // Don't go forever, because that could starve the main simulation.
 143       break;
 144     }
 145     bytes = read(client_fd, recv_buf, buf_size);
 146   }
 147
 148   if (bytes == -1) {
 149     if (errno == EAGAIN) {
 150       // We'll try again the next call.
 151     } else {
 152       fprintf(stderr, "remote_bitbang failed to read on socket: %s (%d)\n",
 153           strerror(errno), errno);
 154       abort();
 155     }
 156   }
 157   if (bytes == 0 || quit) {
 158     // The remote disconnected.
 159     close(client_fd);
 160     client_fd = 0;
 161   }
 162 }