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
  62 void remote_bitbang_t::accept()
  63 {
  64   client_fd = ::accept(socket_fd, NULL, NULL);
  65   if (client_fd == -1) {
  66     if (errno == EAGAIN) {
  67       // No client waiting to connect right now.
  68     } else {
  69       fprintf(stderr, "failed to accept on socket: %s (%d)\n", strerror(errno),
  70           errno);
  71       abort();
  72     }
  73   } else {
  74     fcntl(client_fd, F_SETFL, O_NONBLOCK);
  75   }
  76 }
  77
  78 void remote_bitbang_t::tick()
  79 {
  80   if (client_fd > 0) {
  81     execute_commands();
  82   } else {
  83     this->accept();
  84   }
  85 }
  86
  87 void remote_bitbang_t::execute_commands()
  88 {
  89   const unsigned buf_size = 64 * 1024;
  90   char recv_buf[buf_size];
  91   char send_buf[buf_size];
  92   unsigned total_received = 0;
  93   ssize_t bytes = read(client_fd, recv_buf, buf_size);
  94   while (bytes > 0) {
  95     total_received += bytes;
  96     unsigned send_offset = 0;
  97     for (unsigned i = 0; i < bytes; i++) {
  98       uint8_t command = recv_buf[i];
  99
 100       switch (command) {
 101         case 'B': fprintf(stderr, "*BLINK*\n"); break;
 102         case 'b': fprintf(stderr, "_______\n"); break;
 103         case 'r': tap->reset(); break;
 104         case '0': tap->set_pins(0, 0, 0); break;
 105         case '1': tap->set_pins(0, 0, 1); break;
 106         case '2': tap->set_pins(0, 1, 0); break;
 107         case '3': tap->set_pins(0, 1, 1); break;
 108         case '4': tap->set_pins(1, 0, 0); break;
 109         case '5': tap->set_pins(1, 0, 1); break;
 110         case '6': tap->set_pins(1, 1, 0); break;
 111         case '7': tap->set_pins(1, 1, 1); break;
 112         case 'R': send_buf[send_offset++] = tap->tdo() ? '1' : '0'; break;
 113         default:
 114                   fprintf(stderr, "remote_bitbang got unsupported command '%c'\n",
 115                       command);
 116       }
 117     }
 118     unsigned sent = 0;
 119     while (sent < send_offset) {
 120       bytes = write(client_fd, send_buf + sent, send_offset);
 121       if (bytes == -1) {
 122         fprintf(stderr, "failed to write to socket: %s (%d)\n", strerror(errno), errno);
 123         abort();
 124       }
 125       sent += bytes;
 126     }
 127
 128     if (total_received > buf_size) {
 129       // Don't go forever, because that could starve the main simulation.
 130       break;
 131     }
 132     bytes = read(client_fd, recv_buf, buf_size);
 133   }
 134
 135   if (bytes == -1) {
 136     if (errno == EAGAIN) {
 137       // We'll try again the next call.
 138     } else {
 139       fprintf(stderr, "remote_bitbang failed to read on socket: %s (%d)\n",
 140           strerror(errno), errno);
 141       abort();
 142     }
 143   } else if (bytes == 0) {
 144     // The remote disconnected.
 145     close(client_fd);
 146     client_fd = 0;
 147   }
 148 }