src/jtag/drivers/remote_bitbang.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2
   3 /***************************************************************************
   4  *   Copyright (C) 2011 by Richard Uhler                                   *
   5  *   ruhler@mit.edu                                                        *
   6  ***************************************************************************/
   7
   8 #ifdef HAVE_CONFIG_H
   9 #include "config.h"
  10 #endif
  11
  12 #ifndef _WIN32
  13 #include <sys/un.h>
  14 #include <netdb.h>
  15 #include <netinet/tcp.h>
  16 #endif
  17 #include "helper/system.h"
  18 #include "helper/replacements.h"
  19 #include <jtag/interface.h>
  20 #include "bitbang.h"
  21
  22 /* arbitrary limit on host name length: */
  23 #define REMOTE_BITBANG_HOST_MAX 255
  24
  25 static char *remote_bitbang_host;
  26 static char *remote_bitbang_port;
  27
  28 static int remote_bitbang_fd;
  29 static uint8_t remote_bitbang_send_buf[512];
  30 static unsigned int remote_bitbang_send_buf_used;
  31
  32 /* Circular buffer. When start == end, the buffer is empty. */
  33 static char remote_bitbang_recv_buf[256];
  34 static unsigned int remote_bitbang_recv_buf_start;
  35 static unsigned int remote_bitbang_recv_buf_end;
  36
  37 static bool remote_bitbang_recv_buf_full(void)
  38 {
  39         return remote_bitbang_recv_buf_end ==
  40                 ((remote_bitbang_recv_buf_start + sizeof(remote_bitbang_recv_buf) - 1) %
  41                  sizeof(remote_bitbang_recv_buf));
  42 }
  43
  44 static bool remote_bitbang_recv_buf_empty(void)
  45 {
  46         return remote_bitbang_recv_buf_start == remote_bitbang_recv_buf_end;
  47 }
  48
  49 static unsigned int remote_bitbang_recv_buf_contiguous_available_space(void)
  50 {
  51         if (remote_bitbang_recv_buf_end >= remote_bitbang_recv_buf_start) {
  52                 unsigned int space = sizeof(remote_bitbang_recv_buf) -
  53                                      remote_bitbang_recv_buf_end;
  54                 if (remote_bitbang_recv_buf_start == 0)
  55                         space -= 1;
  56                 return space;
  57         } else {
  58                 return remote_bitbang_recv_buf_start -
  59                        remote_bitbang_recv_buf_end - 1;
  60         }
  61 }
  62
  63 static int remote_bitbang_flush(void)
  64 {
  65         if (remote_bitbang_send_buf_used <= 0)
  66                 return ERROR_OK;
  67
  68         unsigned int offset = 0;
  69         while (offset < remote_bitbang_send_buf_used) {
  70                 ssize_t written = write_socket(remote_bitbang_fd, remote_bitbang_send_buf + offset,
  71                                                                            remote_bitbang_send_buf_used - offset);
  72                 if (written < 0) {
  73                         log_socket_error("remote_bitbang_putc");
  74                         remote_bitbang_send_buf_used = 0;
  75                         return ERROR_FAIL;
  76                 }
  77                 offset += written;
  78         }
  79         remote_bitbang_send_buf_used = 0;
  80         return ERROR_OK;
  81 }
  82
  83 enum block_bool {
  84         NO_BLOCK,
  85         BLOCK
  86 };
  87
  88 /* Read any incoming data, placing it into the buffer. */
  89 static int remote_bitbang_fill_buf(enum block_bool block)
  90 {
  91         if (remote_bitbang_recv_buf_empty()) {
  92                 /* If the buffer is empty, reset it to 0 so we get more
  93                  * contiguous space. */
  94                 remote_bitbang_recv_buf_start = 0;
  95                 remote_bitbang_recv_buf_end = 0;
  96         }
  97
  98         if (block == BLOCK) {
  99                 if (remote_bitbang_flush() != ERROR_OK)
 100                         return ERROR_FAIL;
 101                 socket_block(remote_bitbang_fd);
 102         }
 103
 104         bool first = true;
 105         while (!remote_bitbang_recv_buf_full()) {
 106                 unsigned int contiguous_available_space =
 107                                 remote_bitbang_recv_buf_contiguous_available_space();
 108                 ssize_t count = read_socket(remote_bitbang_fd,
 109                                 remote_bitbang_recv_buf + remote_bitbang_recv_buf_end,
 110                                 contiguous_available_space);
 111                 if (first && block == BLOCK)
 112                         socket_nonblock(remote_bitbang_fd);
 113                 first = false;
 114                 if (count > 0) {
 115                         remote_bitbang_recv_buf_end += count;
 116                         if (remote_bitbang_recv_buf_end == sizeof(remote_bitbang_recv_buf))
 117                                 remote_bitbang_recv_buf_end = 0;
 118                 } else if (count == 0) {
 119                         return ERROR_OK;
 120                 } else if (count < 0) {
 121 #ifdef _WIN32
 122                         if (WSAGetLastError() == WSAEWOULDBLOCK) {
 123 #else
 124                         if (errno == EAGAIN) {
 125 #endif
 126                                 return ERROR_OK;
 127                         } else {
 128                                 log_socket_error("remote_bitbang_fill_buf");
 129                                 return ERROR_FAIL;
 130                         }
 131                 }
 132         }
 133
 134         return ERROR_OK;
 135 }
 136
 137 typedef enum {
 138         NO_FLUSH,
 139         FLUSH_SEND_BUF
 140 } flush_bool_t;
 141
 142 static int remote_bitbang_queue(int c, flush_bool_t flush)
 143 {
 144         remote_bitbang_send_buf[remote_bitbang_send_buf_used++] = c;
 145         if (flush == FLUSH_SEND_BUF ||
 146                         remote_bitbang_send_buf_used >= ARRAY_SIZE(remote_bitbang_send_buf))
 147                 return remote_bitbang_flush();
 148         return ERROR_OK;
 149 }
 150
 151 static int remote_bitbang_quit(void)
 152 {
 153         if (remote_bitbang_queue('Q', FLUSH_SEND_BUF) == ERROR_FAIL)
 154                 return ERROR_FAIL;
 155
 156         if (close_socket(remote_bitbang_fd) != 0) {
 157                 log_socket_error("close_socket");
 158                 return ERROR_FAIL;
 159         }
 160
 161         free(remote_bitbang_host);
 162         free(remote_bitbang_port);
 163
 164         LOG_INFO("remote_bitbang interface quit");
 165         return ERROR_OK;
 166 }
 167
 168 static bb_value_t char_to_int(int c)
 169 {
 170         switch (c) {
 171                 case '0':
 172                         return BB_LOW;
 173                 case '1':
 174                         return BB_HIGH;
 175                 default:
 176                         remote_bitbang_quit();
 177                         LOG_ERROR("remote_bitbang: invalid read response: %c(%i)", c, c);
 178                         return BB_ERROR;
 179         }
 180 }
 181
 182 static int remote_bitbang_sample(void)
 183 {
 184         if (remote_bitbang_fill_buf(NO_BLOCK) != ERROR_OK)
 185                 return ERROR_FAIL;
 186         assert(!remote_bitbang_recv_buf_full());
 187         return remote_bitbang_queue('R', NO_FLUSH);
 188 }
 189
 190 static bb_value_t remote_bitbang_read_sample(void)
 191 {
 192         if (remote_bitbang_recv_buf_empty()) {
 193                 if (remote_bitbang_fill_buf(BLOCK) != ERROR_OK)
 194                         return BB_ERROR;
 195         }
 196         assert(!remote_bitbang_recv_buf_empty());
 197         int c = remote_bitbang_recv_buf[remote_bitbang_recv_buf_start];
 198         remote_bitbang_recv_buf_start =
 199                 (remote_bitbang_recv_buf_start + 1) % sizeof(remote_bitbang_recv_buf);
 200         return char_to_int(c);
 201 }
 202
 203 static int remote_bitbang_write(int tck, int tms, int tdi)
 204 {
 205         char c = '0' + ((tck ? 0x4 : 0x0) | (tms ? 0x2 : 0x0) | (tdi ? 0x1 : 0x0));
 206         return remote_bitbang_queue(c, NO_FLUSH);
 207 }
 208
 209 static int remote_bitbang_reset(int trst, int srst)
 210 {
 211         char c = 'r' + ((trst ? 0x2 : 0x0) | (srst ? 0x1 : 0x0));
 212         /* Always flush the send buffer on reset, because the reset call need not be
 213          * followed by jtag_execute_queue(). */
 214         return remote_bitbang_queue(c, FLUSH_SEND_BUF);
 215 }
 216
 217 static int remote_bitbang_blink(int on)
 218 {
 219         char c = on ? 'B' : 'b';
 220         return remote_bitbang_queue(c, FLUSH_SEND_BUF);
 221 }
 222
 223 static struct bitbang_interface remote_bitbang_bitbang = {
 224         .buf_size = sizeof(remote_bitbang_recv_buf) - 1,
 225         .sample = &remote_bitbang_sample,
 226         .read_sample = &remote_bitbang_read_sample,
 227         .write = &remote_bitbang_write,
 228         .blink = &remote_bitbang_blink,
 229 };
 230
 231 static int remote_bitbang_init_tcp(void)
 232 {
 233         struct addrinfo hints = { .ai_family = AF_UNSPEC, .ai_socktype = SOCK_STREAM };
 234         struct addrinfo *result, *rp;
 235         int fd = 0;
 236
 237         LOG_INFO("Connecting to %s:%s",
 238                         remote_bitbang_host ? remote_bitbang_host : "localhost",
 239                         remote_bitbang_port);
 240
 241         /* Obtain address(es) matching host/port */
 242         int s = getaddrinfo(remote_bitbang_host, remote_bitbang_port, &hints, &result);
 243         if (s != 0) {
 244                 LOG_ERROR("getaddrinfo: %s\n", gai_strerror(s));
 245                 return ERROR_FAIL;
 246         }
 247
 248         /* getaddrinfo() returns a list of address structures.
 249          Try each address until we successfully connect(2).
 250          If socket(2) (or connect(2)) fails, we (close the socket
 251          and) try the next address. */
 252
 253         for (rp = result; rp ; rp = rp->ai_next) {
 254                 fd = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
 255                 if (fd == -1)
 256                         continue;
 257
 258                 if (connect(fd, rp->ai_addr, rp->ai_addrlen) != -1)
 259                         break; /* Success */
 260
 261                 close(fd);
 262         }
 263
 264         /* We work hard to collapse the writes into the minimum number, so when
 265          * we write something we want to get it to the other end of the
 266          * connection as fast as possible. */
 267         int one = 1;
 268         /* On Windows optval has to be a const char *. */
 269         setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, (const char *)&one, sizeof(one));
 270
 271         freeaddrinfo(result); /* No longer needed */
 272
 273         if (!rp) { /* No address succeeded */
 274                 log_socket_error("Failed to connect");
 275                 return ERROR_FAIL;
 276         }
 277
 278         return fd;
 279 }
 280
 281 static int remote_bitbang_init_unix(void)
 282 {
 283         if (!remote_bitbang_host) {
 284                 LOG_ERROR("host/socket not specified");
 285                 return ERROR_FAIL;
 286         }
 287
 288         LOG_INFO("Connecting to unix socket %s", remote_bitbang_host);
 289         int fd = socket(PF_UNIX, SOCK_STREAM, 0);
 290         if (fd < 0) {
 291                 log_socket_error("socket");
 292                 return ERROR_FAIL;
 293         }
 294
 295         struct sockaddr_un addr;
 296         addr.sun_family = AF_UNIX;
 297         strncpy(addr.sun_path, remote_bitbang_host, sizeof(addr.sun_path));
 298         addr.sun_path[sizeof(addr.sun_path)-1] = '\0';
 299
 300         if (connect(fd, (struct sockaddr *)&addr, sizeof(struct sockaddr_un)) < 0) {
 301                 log_socket_error("connect");
 302                 return ERROR_FAIL;
 303         }
 304
 305         return fd;
 306 }
 307
 308 static int remote_bitbang_init(void)
 309 {
 310         bitbang_interface = &remote_bitbang_bitbang;
 311
 312         remote_bitbang_recv_buf_start = 0;
 313         remote_bitbang_recv_buf_end = 0;
 314
 315         LOG_INFO("Initializing remote_bitbang driver");
 316         if (!remote_bitbang_port)
 317                 remote_bitbang_fd = remote_bitbang_init_unix();
 318         else
 319                 remote_bitbang_fd = remote_bitbang_init_tcp();
 320
 321         if (remote_bitbang_fd < 0)
 322                 return remote_bitbang_fd;
 323
 324         socket_nonblock(remote_bitbang_fd);
 325
 326         LOG_INFO("remote_bitbang driver initialized");
 327         return ERROR_OK;
 328 }
 329
 330 COMMAND_HANDLER(remote_bitbang_handle_remote_bitbang_port_command)
 331 {
 332         if (CMD_ARGC == 1) {
 333                 uint16_t port;
 334                 COMMAND_PARSE_NUMBER(u16, CMD_ARGV[0], port);
 335                 free(remote_bitbang_port);
 336                 remote_bitbang_port = port == 0 ? NULL : strdup(CMD_ARGV[0]);
 337                 return ERROR_OK;
 338         }
 339         return ERROR_COMMAND_SYNTAX_ERROR;
 340 }
 341
 342 COMMAND_HANDLER(remote_bitbang_handle_remote_bitbang_host_command)
 343 {
 344         if (CMD_ARGC == 1) {
 345                 free(remote_bitbang_host);
 346                 remote_bitbang_host = strdup(CMD_ARGV[0]);
 347                 return ERROR_OK;
 348         }
 349         return ERROR_COMMAND_SYNTAX_ERROR;
 350 }
 351
 352 static const struct command_registration remote_bitbang_subcommand_handlers[] = {
 353         {
 354                 .name = "port",
 355                 .handler = remote_bitbang_handle_remote_bitbang_port_command,
 356                 .mode = COMMAND_CONFIG,
 357                 .help = "Set the port to use to connect to the remote jtag.\n"
 358                         "  if 0 or unset, use unix sockets to connect to the remote jtag.",
 359                 .usage = "port_number",
 360         },
 361         {
 362                 .name = "host",
 363                 .handler = remote_bitbang_handle_remote_bitbang_host_command,
 364                 .mode = COMMAND_CONFIG,
 365                 .help = "Set the host to use to connect to the remote jtag.\n"
 366                         "  if port is 0 or unset, this is the name of the unix socket to use.",
 367                 .usage = "host_name",
 368         },
 369         COMMAND_REGISTRATION_DONE,
 370 };
 371
 372 static const struct command_registration remote_bitbang_command_handlers[] = {
 373         {
 374                 .name = "remote_bitbang",
 375                 .mode = COMMAND_ANY,
 376                 .help = "perform remote_bitbang management",
 377                 .chain = remote_bitbang_subcommand_handlers,
 378                 .usage = "",
 379         },
 380         COMMAND_REGISTRATION_DONE
 381 };
 382
 383 static int remote_bitbang_execute_queue(void)
 384 {
 385         /* safety: the send buffer must be empty, no leftover characters from
 386          * previous transactions */
 387         assert(remote_bitbang_send_buf_used == 0);
 388
 389         /* process the JTAG command queue */
 390         int ret = bitbang_execute_queue();
 391         if (ret != ERROR_OK)
 392                 return ret;
 393
 394         /* flush not-yet-sent characters, if any */
 395         return remote_bitbang_flush();
 396 }
 397
 398 static struct jtag_interface remote_bitbang_interface = {
 399         .execute_queue = &remote_bitbang_execute_queue,
 400 };
 401
 402 struct adapter_driver remote_bitbang_adapter_driver = {
 403         .name = "remote_bitbang",
 404         .transports = jtag_only,
 405         .commands = remote_bitbang_command_handlers,
 406
 407         .init = &remote_bitbang_init,
 408         .quit = &remote_bitbang_quit,
 409         .reset = &remote_bitbang_reset,
 410
 411         .jtag_ops = &remote_bitbang_interface,
 412 };