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  *   Copyright (C) 2021 by Manuel Wick <manuel@matronix.de>                *
   8  ***************************************************************************/
   9
  10 #ifdef HAVE_CONFIG_H
  11 #include "config.h"
  12 #endif
  13
  14 #ifndef _WIN32
  15 #include <sys/un.h>
  16 #include <netdb.h>
  17 #include <netinet/tcp.h>
  18 #endif
  19 #include "helper/system.h"
  20 #include "helper/replacements.h"
  21 #include <jtag/interface.h>
  22 #include "bitbang.h"
  23
  24 /* arbitrary limit on host name length: */
  25 #define REMOTE_BITBANG_HOST_MAX 255
  26
  27 static char *remote_bitbang_host;
  28 static char *remote_bitbang_port;
  29
  30 static int remote_bitbang_fd;
  31 static uint8_t remote_bitbang_send_buf[512];
  32 static unsigned int remote_bitbang_send_buf_used;
  33
  34 /* Circular buffer. When start == end, the buffer is empty. */
  35 static char remote_bitbang_recv_buf[256];
  36 static unsigned int remote_bitbang_recv_buf_start;
  37 static unsigned int remote_bitbang_recv_buf_end;
  38
  39 static bool remote_bitbang_recv_buf_full(void)
  40 {
  41         return remote_bitbang_recv_buf_end ==
  42                 ((remote_bitbang_recv_buf_start + sizeof(remote_bitbang_recv_buf) - 1) %
  43                  sizeof(remote_bitbang_recv_buf));
  44 }
  45
  46 static bool remote_bitbang_recv_buf_empty(void)
  47 {
  48         return remote_bitbang_recv_buf_start == remote_bitbang_recv_buf_end;
  49 }
  50
  51 static unsigned int remote_bitbang_recv_buf_contiguous_available_space(void)
  52 {
  53         if (remote_bitbang_recv_buf_end >= remote_bitbang_recv_buf_start) {
  54                 unsigned int space = sizeof(remote_bitbang_recv_buf) -
  55                                      remote_bitbang_recv_buf_end;
  56                 if (remote_bitbang_recv_buf_start == 0)
  57                         space -= 1;
  58                 return space;
  59         } else {
  60                 return remote_bitbang_recv_buf_start -
  61                        remote_bitbang_recv_buf_end - 1;
  62         }
  63 }
  64
  65 static int remote_bitbang_flush(void)
  66 {
  67         if (remote_bitbang_send_buf_used <= 0)
  68                 return ERROR_OK;
  69
  70         unsigned int offset = 0;
  71         while (offset < remote_bitbang_send_buf_used) {
  72                 ssize_t written = write_socket(remote_bitbang_fd, remote_bitbang_send_buf + offset,
  73                                                                            remote_bitbang_send_buf_used - offset);
  74                 if (written < 0) {
  75                         log_socket_error("remote_bitbang_putc");
  76                         remote_bitbang_send_buf_used = 0;
  77                         return ERROR_FAIL;
  78                 }
  79                 offset += written;
  80         }
  81         remote_bitbang_send_buf_used = 0;
  82         return ERROR_OK;
  83 }
  84
  85 enum block_bool {
  86         NO_BLOCK,
  87         BLOCK
  88 };
  89
  90 /* Read any incoming data, placing it into the buffer. */
  91 static int remote_bitbang_fill_buf(enum block_bool block)
  92 {
  93         if (remote_bitbang_recv_buf_empty()) {
  94                 /* If the buffer is empty, reset it to 0 so we get more
  95                  * contiguous space. */
  96                 remote_bitbang_recv_buf_start = 0;
  97                 remote_bitbang_recv_buf_end = 0;
  98         }
  99
 100         if (block == BLOCK) {
 101                 if (remote_bitbang_flush() != ERROR_OK)
 102                         return ERROR_FAIL;
 103                 socket_block(remote_bitbang_fd);
 104         }
 105
 106         bool first = true;
 107         while (!remote_bitbang_recv_buf_full()) {
 108                 unsigned int contiguous_available_space =
 109                                 remote_bitbang_recv_buf_contiguous_available_space();
 110                 ssize_t count = read_socket(remote_bitbang_fd,
 111                                 remote_bitbang_recv_buf + remote_bitbang_recv_buf_end,
 112                                 contiguous_available_space);
 113                 if (first && block == BLOCK)
 114                         socket_nonblock(remote_bitbang_fd);
 115                 first = false;
 116                 if (count > 0) {
 117                         remote_bitbang_recv_buf_end += count;
 118                         if (remote_bitbang_recv_buf_end == sizeof(remote_bitbang_recv_buf))
 119                                 remote_bitbang_recv_buf_end = 0;
 120                 } else if (count == 0) {
 121                         return ERROR_OK;
 122                 } else if (count < 0) {
 123 #ifdef _WIN32
 124                         if (WSAGetLastError() == WSAEWOULDBLOCK) {
 125 #else
 126                         if (errno == EAGAIN) {
 127 #endif
 128                                 return ERROR_OK;
 129                         } else {
 130                                 log_socket_error("remote_bitbang_fill_buf");
 131                                 return ERROR_FAIL;
 132                         }
 133                 }
 134         }
 135
 136         return ERROR_OK;
 137 }
 138
 139 typedef enum {
 140         NO_FLUSH,
 141         FLUSH_SEND_BUF
 142 } flush_bool_t;
 143
 144 static int remote_bitbang_queue(int c, flush_bool_t flush)
 145 {
 146         remote_bitbang_send_buf[remote_bitbang_send_buf_used++] = c;
 147         if (flush == FLUSH_SEND_BUF ||
 148                         remote_bitbang_send_buf_used >= ARRAY_SIZE(remote_bitbang_send_buf))
 149                 return remote_bitbang_flush();
 150         return ERROR_OK;
 151 }
 152
 153 static int remote_bitbang_quit(void)
 154 {
 155         if (remote_bitbang_queue('Q', FLUSH_SEND_BUF) == ERROR_FAIL)
 156                 return ERROR_FAIL;
 157
 158         if (close_socket(remote_bitbang_fd) != 0) {
 159                 log_socket_error("close_socket");
 160                 return ERROR_FAIL;
 161         }
 162
 163         free(remote_bitbang_host);
 164         free(remote_bitbang_port);
 165
 166         LOG_INFO("remote_bitbang interface quit");
 167         return ERROR_OK;
 168 }
 169
 170 static bb_value_t char_to_int(int c)
 171 {
 172         switch (c) {
 173                 case '0':
 174                         return BB_LOW;
 175                 case '1':
 176                         return BB_HIGH;
 177                 default:
 178                         remote_bitbang_quit();
 179                         LOG_ERROR("remote_bitbang: invalid read response: %c(%i)", c, c);
 180                         return BB_ERROR;
 181         }
 182 }
 183
 184 static int remote_bitbang_sample(void)
 185 {
 186         if (remote_bitbang_fill_buf(NO_BLOCK) != ERROR_OK)
 187                 return ERROR_FAIL;
 188         assert(!remote_bitbang_recv_buf_full());
 189         return remote_bitbang_queue('R', NO_FLUSH);
 190 }
 191
 192 static bb_value_t remote_bitbang_read_sample(void)
 193 {
 194         if (remote_bitbang_recv_buf_empty()) {
 195                 if (remote_bitbang_fill_buf(BLOCK) != ERROR_OK)
 196                         return BB_ERROR;
 197         }
 198         assert(!remote_bitbang_recv_buf_empty());
 199         int c = remote_bitbang_recv_buf[remote_bitbang_recv_buf_start];
 200         remote_bitbang_recv_buf_start =
 201                 (remote_bitbang_recv_buf_start + 1) % sizeof(remote_bitbang_recv_buf);
 202         return char_to_int(c);
 203 }
 204
 205 static int remote_bitbang_write(int tck, int tms, int tdi)
 206 {
 207         char c = '0' + ((tck ? 0x4 : 0x0) | (tms ? 0x2 : 0x0) | (tdi ? 0x1 : 0x0));
 208         return remote_bitbang_queue(c, NO_FLUSH);
 209 }
 210
 211 static int remote_bitbang_reset(int trst, int srst)
 212 {
 213         char c = 'r' + ((trst ? 0x2 : 0x0) | (srst ? 0x1 : 0x0));
 214         /* Always flush the send buffer on reset, because the reset call need not be
 215          * followed by jtag_execute_queue(). */
 216         return remote_bitbang_queue(c, FLUSH_SEND_BUF);
 217 }
 218
 219 static int remote_bitbang_blink(int on)
 220 {
 221         char c = on ? 'B' : 'b';
 222         return remote_bitbang_queue(c, FLUSH_SEND_BUF);
 223 }
 224
 225 static void remote_bitbang_swdio_drive(bool is_output)
 226 {
 227         char c = is_output ? 'O' : 'o';
 228         if (remote_bitbang_queue(c, FLUSH_SEND_BUF) == ERROR_FAIL)
 229                 LOG_ERROR("Error setting direction for swdio");
 230 }
 231
 232 static int remote_bitbang_swdio_read(void)
 233 {
 234         if (remote_bitbang_queue('c', FLUSH_SEND_BUF) != ERROR_FAIL)
 235                 return remote_bitbang_read_sample();
 236         else
 237                 return BB_ERROR;
 238 }
 239
 240 static int remote_bitbang_swd_write(int swclk, int swdio)
 241 {
 242         char c = 'd' + ((swclk ? 0x2 : 0x0) | (swdio ? 0x1 : 0x0));
 243         return remote_bitbang_queue(c, NO_FLUSH);
 244 }
 245
 246 static struct bitbang_interface remote_bitbang_bitbang = {
 247         .buf_size = sizeof(remote_bitbang_recv_buf) - 1,
 248         .sample = &remote_bitbang_sample,
 249         .read_sample = &remote_bitbang_read_sample,
 250         .write = &remote_bitbang_write,
 251         .swdio_read = &remote_bitbang_swdio_read,
 252         .swdio_drive = &remote_bitbang_swdio_drive,
 253         .swd_write = &remote_bitbang_swd_write,
 254         .blink = &remote_bitbang_blink,
 255 };
 256
 257 static int remote_bitbang_init_tcp(void)
 258 {
 259         struct addrinfo hints = { .ai_family = AF_UNSPEC, .ai_socktype = SOCK_STREAM };
 260         struct addrinfo *result, *rp;
 261         int fd = 0;
 262
 263         LOG_INFO("Connecting to %s:%s",
 264                         remote_bitbang_host ? remote_bitbang_host : "localhost",
 265                         remote_bitbang_port);
 266
 267         /* Obtain address(es) matching host/port */
 268         int s = getaddrinfo(remote_bitbang_host, remote_bitbang_port, &hints, &result);
 269         if (s != 0) {
 270                 LOG_ERROR("getaddrinfo: %s\n", gai_strerror(s));
 271                 return ERROR_FAIL;
 272         }
 273
 274         /* getaddrinfo() returns a list of address structures.
 275          Try each address until we successfully connect(2).
 276          If socket(2) (or connect(2)) fails, we (close the socket
 277          and) try the next address. */
 278
 279         for (rp = result; rp ; rp = rp->ai_next) {
 280                 fd = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
 281                 if (fd == -1)
 282                         continue;
 283
 284                 if (connect(fd, rp->ai_addr, rp->ai_addrlen) != -1)
 285                         break; /* Success */
 286
 287                 close(fd);
 288         }
 289
 290         /* We work hard to collapse the writes into the minimum number, so when
 291          * we write something we want to get it to the other end of the
 292          * connection as fast as possible. */
 293         int one = 1;
 294         /* On Windows optval has to be a const char *. */
 295         setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, (const char *)&one, sizeof(one));
 296
 297         freeaddrinfo(result); /* No longer needed */
 298
 299         if (!rp) { /* No address succeeded */
 300                 log_socket_error("Failed to connect");
 301                 return ERROR_FAIL;
 302         }
 303
 304         return fd;
 305 }
 306
 307 static int remote_bitbang_init_unix(void)
 308 {
 309         if (!remote_bitbang_host) {
 310                 LOG_ERROR("host/socket not specified");
 311                 return ERROR_FAIL;
 312         }
 313
 314         LOG_INFO("Connecting to unix socket %s", remote_bitbang_host);
 315         int fd = socket(PF_UNIX, SOCK_STREAM, 0);
 316         if (fd < 0) {
 317                 log_socket_error("socket");
 318                 return ERROR_FAIL;
 319         }
 320
 321         struct sockaddr_un addr;
 322         addr.sun_family = AF_UNIX;
 323         strncpy(addr.sun_path, remote_bitbang_host, sizeof(addr.sun_path));
 324         addr.sun_path[sizeof(addr.sun_path)-1] = '\0';
 325
 326         if (connect(fd, (struct sockaddr *)&addr, sizeof(struct sockaddr_un)) < 0) {
 327                 log_socket_error("connect");
 328                 return ERROR_FAIL;
 329         }
 330
 331         return fd;
 332 }
 333
 334 static int remote_bitbang_init(void)
 335 {
 336         bitbang_interface = &remote_bitbang_bitbang;
 337
 338         remote_bitbang_recv_buf_start = 0;
 339         remote_bitbang_recv_buf_end = 0;
 340
 341         LOG_INFO("Initializing remote_bitbang driver");
 342         if (!remote_bitbang_port)
 343                 remote_bitbang_fd = remote_bitbang_init_unix();
 344         else
 345                 remote_bitbang_fd = remote_bitbang_init_tcp();
 346
 347         if (remote_bitbang_fd < 0)
 348                 return remote_bitbang_fd;
 349
 350         socket_nonblock(remote_bitbang_fd);
 351
 352         LOG_INFO("remote_bitbang driver initialized");
 353         return ERROR_OK;
 354 }
 355
 356 COMMAND_HANDLER(remote_bitbang_handle_remote_bitbang_port_command)
 357 {
 358         if (CMD_ARGC == 1) {
 359                 uint16_t port;
 360                 COMMAND_PARSE_NUMBER(u16, CMD_ARGV[0], port);
 361                 free(remote_bitbang_port);
 362                 remote_bitbang_port = port == 0 ? NULL : strdup(CMD_ARGV[0]);
 363                 return ERROR_OK;
 364         }
 365         return ERROR_COMMAND_SYNTAX_ERROR;
 366 }
 367
 368 COMMAND_HANDLER(remote_bitbang_handle_remote_bitbang_host_command)
 369 {
 370         if (CMD_ARGC == 1) {
 371                 free(remote_bitbang_host);
 372                 remote_bitbang_host = strdup(CMD_ARGV[0]);
 373                 return ERROR_OK;
 374         }
 375         return ERROR_COMMAND_SYNTAX_ERROR;
 376 }
 377
 378 static const char * const remote_bitbang_transports[] = { "jtag", "swd", NULL };
 379
 380 static const struct command_registration remote_bitbang_subcommand_handlers[] = {
 381         {
 382                 .name = "port",
 383                 .handler = remote_bitbang_handle_remote_bitbang_port_command,
 384                 .mode = COMMAND_CONFIG,
 385                 .help = "Set the port to use to connect to the remote jtag.\n"
 386                         "  if 0 or unset, use unix sockets to connect to the remote jtag.",
 387                 .usage = "port_number",
 388         },
 389         {
 390                 .name = "host",
 391                 .handler = remote_bitbang_handle_remote_bitbang_host_command,
 392                 .mode = COMMAND_CONFIG,
 393                 .help = "Set the host to use to connect to the remote jtag.\n"
 394                         "  if port is 0 or unset, this is the name of the unix socket to use.",
 395                 .usage = "host_name",
 396         },
 397         COMMAND_REGISTRATION_DONE,
 398 };
 399
 400 static const struct command_registration remote_bitbang_command_handlers[] = {
 401         {
 402                 .name = "remote_bitbang",
 403                 .mode = COMMAND_ANY,
 404                 .help = "perform remote_bitbang management",
 405                 .chain = remote_bitbang_subcommand_handlers,
 406                 .usage = "",
 407         },
 408         COMMAND_REGISTRATION_DONE
 409 };
 410
 411 static int remote_bitbang_execute_queue(void)
 412 {
 413         /* safety: the send buffer must be empty, no leftover characters from
 414          * previous transactions */
 415         assert(remote_bitbang_send_buf_used == 0);
 416
 417         /* process the JTAG command queue */
 418         int ret = bitbang_execute_queue();
 419         if (ret != ERROR_OK)
 420                 return ret;
 421
 422         /* flush not-yet-sent characters, if any */
 423         return remote_bitbang_flush();
 424 }
 425
 426 static struct jtag_interface remote_bitbang_interface = {
 427         .execute_queue = &remote_bitbang_execute_queue,
 428 };
 429
 430 struct adapter_driver remote_bitbang_adapter_driver = {
 431         .name = "remote_bitbang",
 432         .transports = remote_bitbang_transports,
 433         .commands = remote_bitbang_command_handlers,
 434
 435         .init = &remote_bitbang_init,
 436         .quit = &remote_bitbang_quit,
 437         .reset = &remote_bitbang_reset,
 438
 439         .jtag_ops = &remote_bitbang_interface,
 440         .swd_ops = &bitbang_swd,
 441 };