src/jtag/drivers/remote_bitbang.c

   1 /***************************************************************************
   2  *   Copyright (C) 2011 by Richard Uhler                                   *
   3  *   ruhler@mit.edu                                                        *
   4  *                                                                         *
   5  *   This program is free software; you can redistribute it and/or modify  *
   6  *   it under the terms of the GNU General Public License as published by  *
   7  *   the Free Software Foundation; either version 2 of the License, or     *
   8  *   (at your option) any later version.                                   *
   9  *                                                                         *
  10  *   This program is distributed in the hope that it will be useful,       *
  11  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  12  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  13  *   GNU General Public License for more details.                          *
  14  *                                                                         *
  15  *   You should have received a copy of the GNU General Public License     *
  16  *   along with this program.  If not, see <http://www.gnu.org/licenses/>. *
  17  ***************************************************************************/
  18
  19 #ifdef HAVE_CONFIG_H
  20 #include "config.h"
  21 #endif
  22
  23 #ifndef _WIN32
  24 #include <sys/un.h>
  25 #include <netdb.h>
  26 #endif
  27 #include <jtag/interface.h>
  28 #include "bitbang.h"
  29
  30 /* arbitrary limit on host name length: */
  31 #define REMOTE_BITBANG_HOST_MAX 255
  32
  33 static char *remote_bitbang_host;
  34 static char *remote_bitbang_port;
  35
  36 static FILE *remote_bitbang_file;
  37 static int remote_bitbang_fd;
  38
  39 /* Circular buffer. When start == end, the buffer is empty. */
  40 static char remote_bitbang_buf[64];
  41 static unsigned remote_bitbang_start;
  42 static unsigned remote_bitbang_end;
  43
  44 static int remote_bitbang_buf_full(void)
  45 {
  46         return remote_bitbang_end ==
  47                 ((remote_bitbang_start + sizeof(remote_bitbang_buf) - 1) %
  48                  sizeof(remote_bitbang_buf));
  49 }
  50
  51 /* Read any incoming data, placing it into the buffer. */
  52 static int remote_bitbang_fill_buf(void)
  53 {
  54         socket_nonblock(remote_bitbang_fd);
  55         while (!remote_bitbang_buf_full()) {
  56                 unsigned contiguous_available_space;
  57                 if (remote_bitbang_end >= remote_bitbang_start) {
  58                         contiguous_available_space = sizeof(remote_bitbang_buf) -
  59                                 remote_bitbang_end;
  60                         if (remote_bitbang_start == 0)
  61                                 contiguous_available_space -= 1;
  62                 } else {
  63                         contiguous_available_space = remote_bitbang_start -
  64                                 remote_bitbang_end - 1;
  65                 }
  66                 ssize_t count = read(remote_bitbang_fd,
  67                                 remote_bitbang_buf + remote_bitbang_end,
  68                                 contiguous_available_space);
  69                 if (count > 0) {
  70                         remote_bitbang_end += count;
  71                         if (remote_bitbang_end == sizeof(remote_bitbang_buf))
  72                                 remote_bitbang_end = 0;
  73                 } else if (count == 0) {
  74                         return ERROR_OK;
  75                 } else if (count < 0) {
  76                         if (errno == EAGAIN) {
  77                                 return ERROR_OK;
  78                         } else {
  79                                 LOG_ERROR("remote_bitbang_fill_buf: %s (%d)",
  80                                                 strerror(errno), errno);
  81                                 return ERROR_FAIL;
  82                         }
  83                 }
  84         }
  85
  86         return ERROR_OK;
  87 }
  88
  89 static int remote_bitbang_putc(int c)
  90 {
  91         if (EOF == fputc(c, remote_bitbang_file)) {
  92                 LOG_ERROR("remote_bitbang_putc: %s", strerror(errno));
  93                 return ERROR_FAIL;
  94         }
  95         return ERROR_OK;
  96 }
  97
  98 static int remote_bitbang_quit(void)
  99 {
 100         if (EOF == fputc('Q', remote_bitbang_file)) {
 101                 LOG_ERROR("fputs: %s", strerror(errno));
 102                 return ERROR_FAIL;
 103         }
 104
 105         if (EOF == fflush(remote_bitbang_file)) {
 106                 LOG_ERROR("fflush: %s", strerror(errno));
 107                 return ERROR_FAIL;
 108         }
 109
 110         /* We only need to close one of the FILE*s, because they both use the same */
 111         /* underlying file descriptor. */
 112         if (EOF == fclose(remote_bitbang_file)) {
 113                 LOG_ERROR("fclose: %s", strerror(errno));
 114                 return ERROR_FAIL;
 115         }
 116
 117         free(remote_bitbang_host);
 118         free(remote_bitbang_port);
 119
 120         LOG_INFO("remote_bitbang interface quit");
 121         return ERROR_OK;
 122 }
 123
 124 static bb_value_t char_to_int(int c)
 125 {
 126         switch (c) {
 127                 case '0':
 128                         return BB_LOW;
 129                 case '1':
 130                         return BB_HIGH;
 131                 default:
 132                         remote_bitbang_quit();
 133                         LOG_ERROR("remote_bitbang: invalid read response: %c(%i)", c, c);
 134                         return BB_ERROR;
 135         }
 136 }
 137
 138 /* Get the next read response. */
 139 static bb_value_t remote_bitbang_rread(void)
 140 {
 141         if (EOF == fflush(remote_bitbang_file)) {
 142                 remote_bitbang_quit();
 143                 LOG_ERROR("fflush: %s", strerror(errno));
 144                 return BB_ERROR;
 145         }
 146
 147         /* Enable blocking access. */
 148         socket_block(remote_bitbang_fd);
 149         char c;
 150         ssize_t count = read(remote_bitbang_fd, &c, 1);
 151         if (count == 1) {
 152                 return char_to_int(c);
 153         } else {
 154                 remote_bitbang_quit();
 155                 LOG_ERROR("read: count=%d, error=%s", (int) count, strerror(errno));
 156                 return BB_ERROR;
 157         }
 158 }
 159
 160 static int remote_bitbang_sample(void)
 161 {
 162         if (remote_bitbang_fill_buf() != ERROR_OK)
 163                 return ERROR_FAIL;
 164         assert(!remote_bitbang_buf_full());
 165         return remote_bitbang_putc('R');
 166 }
 167
 168 static bb_value_t remote_bitbang_read_sample(void)
 169 {
 170         if (remote_bitbang_start != remote_bitbang_end) {
 171                 int c = remote_bitbang_buf[remote_bitbang_start];
 172                 remote_bitbang_start =
 173                         (remote_bitbang_start + 1) % sizeof(remote_bitbang_buf);
 174                 return char_to_int(c);
 175         }
 176         return remote_bitbang_rread();
 177 }
 178
 179 static int remote_bitbang_write(int tck, int tms, int tdi)
 180 {
 181         char c = '0' + ((tck ? 0x4 : 0x0) | (tms ? 0x2 : 0x0) | (tdi ? 0x1 : 0x0));
 182         return remote_bitbang_putc(c);
 183 }
 184
 185 static int remote_bitbang_reset(int trst, int srst)
 186 {
 187         char c = 'r' + ((trst ? 0x2 : 0x0) | (srst ? 0x1 : 0x0));
 188         return remote_bitbang_putc(c);
 189 }
 190
 191 static int remote_bitbang_blink(int on)
 192 {
 193         char c = on ? 'B' : 'b';
 194         return remote_bitbang_putc(c);
 195 }
 196
 197 static struct bitbang_interface remote_bitbang_bitbang = {
 198         .buf_size = sizeof(remote_bitbang_buf) - 1,
 199         .sample = &remote_bitbang_sample,
 200         .read_sample = &remote_bitbang_read_sample,
 201         .write = &remote_bitbang_write,
 202         .reset = &remote_bitbang_reset,
 203         .blink = &remote_bitbang_blink,
 204 };
 205
 206 static int remote_bitbang_init_tcp(void)
 207 {
 208         struct addrinfo hints = { .ai_family = AF_UNSPEC, .ai_socktype = SOCK_STREAM };
 209         struct addrinfo *result, *rp;
 210         int fd = 0;
 211
 212         LOG_INFO("Connecting to %s:%s",
 213                         remote_bitbang_host ? remote_bitbang_host : "localhost",
 214                         remote_bitbang_port);
 215
 216         /* Obtain address(es) matching host/port */
 217         int s = getaddrinfo(remote_bitbang_host, remote_bitbang_port, &hints, &result);
 218         if (s != 0) {
 219                 LOG_ERROR("getaddrinfo: %s\n", gai_strerror(s));
 220                 return ERROR_FAIL;
 221         }
 222
 223         /* getaddrinfo() returns a list of address structures.
 224          Try each address until we successfully connect(2).
 225          If socket(2) (or connect(2)) fails, we (close the socket
 226          and) try the next address. */
 227
 228         for (rp = result; rp != NULL ; rp = rp->ai_next) {
 229                 fd = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
 230                 if (fd == -1)
 231                         continue;
 232
 233                 if (connect(fd, rp->ai_addr, rp->ai_addrlen) != -1)
 234                         break; /* Success */
 235
 236                 close(fd);
 237         }
 238
 239         freeaddrinfo(result); /* No longer needed */
 240
 241         if (rp == NULL) { /* No address succeeded */
 242                 LOG_ERROR("Failed to connect: %s", strerror(errno));
 243                 return ERROR_FAIL;
 244         }
 245
 246         return fd;
 247 }
 248
 249 static int remote_bitbang_init_unix(void)
 250 {
 251         if (remote_bitbang_host == NULL) {
 252                 LOG_ERROR("host/socket not specified");
 253                 return ERROR_FAIL;
 254         }
 255
 256         LOG_INFO("Connecting to unix socket %s", remote_bitbang_host);
 257         int fd = socket(PF_UNIX, SOCK_STREAM, 0);
 258         if (fd < 0) {
 259                 LOG_ERROR("socket: %s", strerror(errno));
 260                 return ERROR_FAIL;
 261         }
 262
 263         struct sockaddr_un addr;
 264         addr.sun_family = AF_UNIX;
 265         strncpy(addr.sun_path, remote_bitbang_host, sizeof(addr.sun_path));
 266         addr.sun_path[sizeof(addr.sun_path)-1] = '\0';
 267
 268         if (connect(fd, (struct sockaddr *)&addr, sizeof(struct sockaddr_un)) < 0) {
 269                 LOG_ERROR("connect: %s", strerror(errno));
 270                 return ERROR_FAIL;
 271         }
 272
 273         return fd;
 274 }
 275
 276 static int remote_bitbang_init(void)
 277 {
 278         bitbang_interface = &remote_bitbang_bitbang;
 279
 280         remote_bitbang_start = 0;
 281         remote_bitbang_end = 0;
 282
 283         LOG_INFO("Initializing remote_bitbang driver");
 284         if (remote_bitbang_port == NULL)
 285                 remote_bitbang_fd = remote_bitbang_init_unix();
 286         else
 287                 remote_bitbang_fd = remote_bitbang_init_tcp();
 288
 289         if (remote_bitbang_fd < 0)
 290                 return remote_bitbang_fd;
 291
 292         remote_bitbang_file = fdopen(remote_bitbang_fd, "w+");
 293         if (remote_bitbang_file == NULL) {
 294                 LOG_ERROR("fdopen: failed to open write stream");
 295                 close(remote_bitbang_fd);
 296                 return ERROR_FAIL;
 297         }
 298
 299         LOG_INFO("remote_bitbang driver initialized");
 300         return ERROR_OK;
 301 }
 302
 303 COMMAND_HANDLER(remote_bitbang_handle_remote_bitbang_port_command)
 304 {
 305         if (CMD_ARGC == 1) {
 306                 uint16_t port;
 307                 COMMAND_PARSE_NUMBER(u16, CMD_ARGV[0], port);
 308                 free(remote_bitbang_port);
 309                 remote_bitbang_port = port == 0 ? NULL : strdup(CMD_ARGV[0]);
 310                 return ERROR_OK;
 311         }
 312         return ERROR_COMMAND_SYNTAX_ERROR;
 313 }
 314
 315 COMMAND_HANDLER(remote_bitbang_handle_remote_bitbang_host_command)
 316 {
 317         if (CMD_ARGC == 1) {
 318                 free(remote_bitbang_host);
 319                 remote_bitbang_host = strdup(CMD_ARGV[0]);
 320                 return ERROR_OK;
 321         }
 322         return ERROR_COMMAND_SYNTAX_ERROR;
 323 }
 324
 325 static const struct command_registration remote_bitbang_command_handlers[] = {
 326         {
 327                 .name = "remote_bitbang_port",
 328                 .handler = remote_bitbang_handle_remote_bitbang_port_command,
 329                 .mode = COMMAND_CONFIG,
 330                 .help = "Set the port to use to connect to the remote jtag.\n"
 331                         "  if 0 or unset, use unix sockets to connect to the remote jtag.",
 332                 .usage = "port_number",
 333         },
 334         {
 335                 .name = "remote_bitbang_host",
 336                 .handler = remote_bitbang_handle_remote_bitbang_host_command,
 337                 .mode = COMMAND_CONFIG,
 338                 .help = "Set the host to use to connect to the remote jtag.\n"
 339                         "  if port is 0 or unset, this is the name of the unix socket to use.",
 340                 .usage = "host_name",
 341         },
 342         COMMAND_REGISTRATION_DONE,
 343 };
 344
 345 struct jtag_interface remote_bitbang_interface = {
 346         .name = "remote_bitbang",
 347         .execute_queue = &bitbang_execute_queue,
 348         .commands = remote_bitbang_command_handlers,
 349         .init = &remote_bitbang_init,
 350         .quit = &remote_bitbang_quit,
 351 };