drivers/serial/serial.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * (C) Copyright 2004
   4  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
   5  */
   6
   7 #include <common.h>
   8 #include <environment.h>
   9 #include <serial.h>
  10 #include <stdio_dev.h>
  11 #include <post.h>
  12 #include <linux/compiler.h>
  13 #include <errno.h>
  14
  15 DECLARE_GLOBAL_DATA_PTR;
  16
  17 static struct serial_device *serial_devices;
  18 static struct serial_device *serial_current;
  19 /*
  20  * Table with supported baudrates (defined in config_xyz.h)
  21  */
  22 static const unsigned long baudrate_table[] = CONFIG_SYS_BAUDRATE_TABLE;
  23
  24 /**
  25  * serial_null() - Void registration routine of a serial driver
  26  *
  27  * This routine implements a void registration routine of a serial
  28  * driver. The registration routine of a particular driver is aliased
  29  * to this empty function in case the driver is not compiled into
  30  * U-Boot.
  31  */
  32 static void serial_null(void)
  33 {
  34 }
  35
  36 /**
  37  * on_baudrate() - Update the actual baudrate when the env var changes
  38  *
  39  * This will check for a valid baudrate and only apply it if valid.
  40  */
  41 static int on_baudrate(const char *name, const char *value, enum env_op op,
  42         int flags)
  43 {
  44         int i;
  45         int baudrate;
  46
  47         switch (op) {
  48         case env_op_create:
  49         case env_op_overwrite:
  50                 /*
  51                  * Switch to new baudrate if new baudrate is supported
  52                  */
  53                 baudrate = simple_strtoul(value, NULL, 10);
  54
  55                 /* Not actually changing */
  56                 if (gd->baudrate == baudrate)
  57                         return 0;
  58
  59                 for (i = 0; i < ARRAY_SIZE(baudrate_table); ++i) {
  60                         if (baudrate == baudrate_table[i])
  61                                 break;
  62                 }
  63                 if (i == ARRAY_SIZE(baudrate_table)) {
  64                         if ((flags & H_FORCE) == 0)
  65                                 printf("## Baudrate %d bps not supported\n",
  66                                         baudrate);
  67                         return 1;
  68                 }
  69                 if ((flags & H_INTERACTIVE) != 0) {
  70                         printf("## Switch baudrate to %d"
  71                                 " bps and press ENTER ...\n", baudrate);
  72                         udelay(50000);
  73                 }
  74
  75                 gd->baudrate = baudrate;
  76
  77                 serial_setbrg();
  78
  79                 udelay(50000);
  80
  81                 if ((flags & H_INTERACTIVE) != 0)
  82                         while (1) {
  83                                 if (getc() == '\r')
  84                                         break;
  85                         }
  86
  87                 return 0;
  88         case env_op_delete:
  89                 printf("## Baudrate may not be deleted\n");
  90                 return 1;
  91         default:
  92                 return 0;
  93         }
  94 }
  95 U_BOOT_ENV_CALLBACK(baudrate, on_baudrate);
  96
  97 /**
  98  * serial_initfunc() - Forward declare of driver registration routine
  99  * @name:       Name of the real driver registration routine.
 100  *
 101  * This macro expands onto forward declaration of a driver registration
 102  * routine, which is then used below in serial_initialize() function.
 103  * The declaration is made weak and aliases to serial_null() so in case
 104  * the driver is not compiled in, the function is still declared and can
 105  * be used, but aliases to serial_null() and thus is optimized away.
 106  */
 107 #define serial_initfunc(name)                                   \
 108         void name(void)                                         \
 109                 __attribute__((weak, alias("serial_null")));
 110
 111 serial_initfunc(atmel_serial_initialize);
 112 serial_initfunc(au1x00_serial_initialize);
 113 serial_initfunc(mcf_serial_initialize);
 114 serial_initfunc(mpc85xx_serial_initialize);
 115 serial_initfunc(mpc8xx_serial_initialize);
 116 serial_initfunc(mxc_serial_initialize);
 117 serial_initfunc(ns16550_serial_initialize);
 118 serial_initfunc(pl01x_serial_initialize);
 119 serial_initfunc(pxa_serial_initialize);
 120 serial_initfunc(sh_serial_initialize);
 121
 122 /**
 123  * serial_register() - Register serial driver with serial driver core
 124  * @dev:        Pointer to the serial driver structure
 125  *
 126  * This function registers the serial driver supplied via @dev with
 127  * serial driver core, thus making U-Boot aware of it and making it
 128  * available for U-Boot to use. On platforms that still require manual
 129  * relocation of constant variables, relocation of the supplied structure
 130  * is performed.
 131  */
 132 void serial_register(struct serial_device *dev)
 133 {
 134 #ifdef CONFIG_NEEDS_MANUAL_RELOC
 135         if (dev->start)
 136                 dev->start += gd->reloc_off;
 137         if (dev->stop)
 138                 dev->stop += gd->reloc_off;
 139         if (dev->setbrg)
 140                 dev->setbrg += gd->reloc_off;
 141         if (dev->getc)
 142                 dev->getc += gd->reloc_off;
 143         if (dev->tstc)
 144                 dev->tstc += gd->reloc_off;
 145         if (dev->putc)
 146                 dev->putc += gd->reloc_off;
 147         if (dev->puts)
 148                 dev->puts += gd->reloc_off;
 149 #endif
 150
 151         dev->next = serial_devices;
 152         serial_devices = dev;
 153 }
 154
 155 /**
 156  * serial_initialize() - Register all compiled-in serial port drivers
 157  *
 158  * This function registers all serial port drivers that are compiled
 159  * into the U-Boot binary with the serial core, thus making them
 160  * available to U-Boot to use. Lastly, this function assigns a default
 161  * serial port to the serial core. That serial port is then used as a
 162  * default output.
 163  */
 164 void serial_initialize(void)
 165 {
 166         atmel_serial_initialize();
 167         au1x00_serial_initialize();
 168         mcf_serial_initialize();
 169         mpc85xx_serial_initialize();
 170         mpc8xx_serial_initialize();
 171         mxc_serial_initialize();
 172         ns16550_serial_initialize();
 173         pl01x_serial_initialize();
 174         pxa_serial_initialize();
 175         sh_serial_initialize();
 176
 177         serial_assign(default_serial_console()->name);
 178 }
 179
 180 static int serial_stub_start(struct stdio_dev *sdev)
 181 {
 182         struct serial_device *dev = sdev->priv;
 183
 184         return dev->start();
 185 }
 186
 187 static int serial_stub_stop(struct stdio_dev *sdev)
 188 {
 189         struct serial_device *dev = sdev->priv;
 190
 191         return dev->stop();
 192 }
 193
 194 static void serial_stub_putc(struct stdio_dev *sdev, const char ch)
 195 {
 196         struct serial_device *dev = sdev->priv;
 197
 198         dev->putc(ch);
 199 }
 200
 201 static void serial_stub_puts(struct stdio_dev *sdev, const char *str)
 202 {
 203         struct serial_device *dev = sdev->priv;
 204
 205         dev->puts(str);
 206 }
 207
 208 static int serial_stub_getc(struct stdio_dev *sdev)
 209 {
 210         struct serial_device *dev = sdev->priv;
 211
 212         return dev->getc();
 213 }
 214
 215 static int serial_stub_tstc(struct stdio_dev *sdev)
 216 {
 217         struct serial_device *dev = sdev->priv;
 218
 219         return dev->tstc();
 220 }
 221
 222 /**
 223  * serial_stdio_init() - Register serial ports with STDIO core
 224  *
 225  * This function generates a proxy driver for each serial port driver.
 226  * These proxy drivers then register with the STDIO core, making the
 227  * serial drivers available as STDIO devices.
 228  */
 229 void serial_stdio_init(void)
 230 {
 231         struct stdio_dev dev;
 232         struct serial_device *s = serial_devices;
 233
 234         while (s) {
 235                 memset(&dev, 0, sizeof(dev));
 236
 237                 strcpy(dev.name, s->name);
 238                 dev.flags = DEV_FLAGS_OUTPUT | DEV_FLAGS_INPUT;
 239
 240                 dev.start = serial_stub_start;
 241                 dev.stop = serial_stub_stop;
 242                 dev.putc = serial_stub_putc;
 243                 dev.puts = serial_stub_puts;
 244                 dev.getc = serial_stub_getc;
 245                 dev.tstc = serial_stub_tstc;
 246                 dev.priv = s;
 247
 248                 stdio_register(&dev);
 249
 250                 s = s->next;
 251         }
 252 }
 253
 254 /**
 255  * serial_assign() - Select the serial output device by name
 256  * @name:       Name of the serial driver to be used as default output
 257  *
 258  * This function configures the serial output multiplexing by
 259  * selecting which serial device will be used as default. In case
 260  * the STDIO "serial" device is selected as stdin/stdout/stderr,
 261  * the serial device previously configured by this function will be
 262  * used for the particular operation.
 263  *
 264  * Returns 0 on success, negative on error.
 265  */
 266 int serial_assign(const char *name)
 267 {
 268         struct serial_device *s;
 269
 270         for (s = serial_devices; s; s = s->next) {
 271                 if (strcmp(s->name, name))
 272                         continue;
 273                 serial_current = s;
 274                 return 0;
 275         }
 276
 277         return -EINVAL;
 278 }
 279
 280 /**
 281  * serial_reinit_all() - Reinitialize all compiled-in serial ports
 282  *
 283  * This function reinitializes all serial ports that are compiled
 284  * into U-Boot by calling their serial_start() functions.
 285  */
 286 void serial_reinit_all(void)
 287 {
 288         struct serial_device *s;
 289
 290         for (s = serial_devices; s; s = s->next)
 291                 s->start();
 292 }
 293
 294 /**
 295  * get_current() - Return pointer to currently selected serial port
 296  *
 297  * This function returns a pointer to currently selected serial port.
 298  * The currently selected serial port is altered by serial_assign()
 299  * function.
 300  *
 301  * In case this function is called before relocation or before any serial
 302  * port is configured, this function calls default_serial_console() to
 303  * determine the serial port. Otherwise, the configured serial port is
 304  * returned.
 305  *
 306  * Returns pointer to the currently selected serial port on success,
 307  * NULL on error.
 308  */
 309 static struct serial_device *get_current(void)
 310 {
 311         struct serial_device *dev;
 312
 313         if (!(gd->flags & GD_FLG_RELOC))
 314                 dev = default_serial_console();
 315         else if (!serial_current)
 316                 dev = default_serial_console();
 317         else
 318                 dev = serial_current;
 319
 320         /* We must have a console device */
 321         if (!dev) {
 322 #ifdef CONFIG_SPL_BUILD
 323                 puts("Cannot find console\n");
 324                 hang();
 325 #else
 326                 panic("Cannot find console\n");
 327 #endif
 328         }
 329
 330         return dev;
 331 }
 332
 333 /**
 334  * serial_init() - Initialize currently selected serial port
 335  *
 336  * This function initializes the currently selected serial port. This
 337  * usually involves setting up the registers of that particular port,
 338  * enabling clock and such. This function uses the get_current() call
 339  * to determine which port is selected.
 340  *
 341  * Returns 0 on success, negative on error.
 342  */
 343 int serial_init(void)
 344 {
 345         gd->flags |= GD_FLG_SERIAL_READY;
 346         return get_current()->start();
 347 }
 348
 349 /**
 350  * serial_setbrg() - Configure baud-rate of currently selected serial port
 351  *
 352  * This function configures the baud-rate of the currently selected
 353  * serial port. The baud-rate is retrieved from global data within
 354  * the serial port driver. This function uses the get_current() call
 355  * to determine which port is selected.
 356  *
 357  * Returns 0 on success, negative on error.
 358  */
 359 void serial_setbrg(void)
 360 {
 361         get_current()->setbrg();
 362 }
 363
 364 /**
 365  * serial_getc() - Read character from currently selected serial port
 366  *
 367  * This function retrieves a character from currently selected serial
 368  * port. In case there is no character waiting on the serial port,
 369  * this function will block and wait for the character to appear. This
 370  * function uses the get_current() call to determine which port is
 371  * selected.
 372  *
 373  * Returns the character on success, negative on error.
 374  */
 375 int serial_getc(void)
 376 {
 377         return get_current()->getc();
 378 }
 379
 380 /**
 381  * serial_tstc() - Test if data is available on currently selected serial port
 382  *
 383  * This function tests if one or more characters are available on
 384  * currently selected serial port. This function never blocks. This
 385  * function uses the get_current() call to determine which port is
 386  * selected.
 387  *
 388  * Returns positive if character is available, zero otherwise.
 389  */
 390 int serial_tstc(void)
 391 {
 392         return get_current()->tstc();
 393 }
 394
 395 /**
 396  * serial_putc() - Output character via currently selected serial port
 397  * @c:  Single character to be output from the serial port.
 398  *
 399  * This function outputs a character via currently selected serial
 400  * port. This character is passed to the serial port driver responsible
 401  * for controlling the hardware. The hardware may still be in process
 402  * of transmitting another character, therefore this function may block
 403  * for a short amount of time. This function uses the get_current()
 404  * call to determine which port is selected.
 405  */
 406 void serial_putc(const char c)
 407 {
 408         get_current()->putc(c);
 409 }
 410
 411 /**
 412  * serial_puts() - Output string via currently selected serial port
 413  * @s:  Zero-terminated string to be output from the serial port.
 414  *
 415  * This function outputs a zero-terminated string via currently
 416  * selected serial port. This function behaves as an accelerator
 417  * in case the hardware can queue multiple characters for transfer.
 418  * The whole string that is to be output is available to the function
 419  * implementing the hardware manipulation. Transmitting the whole
 420  * string may take some time, thus this function may block for some
 421  * amount of time. This function uses the get_current() call to
 422  * determine which port is selected.
 423  */
 424 void serial_puts(const char *s)
 425 {
 426         get_current()->puts(s);
 427 }
 428
 429 /**
 430  * default_serial_puts() - Output string by calling serial_putc() in loop
 431  * @s:  Zero-terminated string to be output from the serial port.
 432  *
 433  * This function outputs a zero-terminated string by calling serial_putc()
 434  * in a loop. Most drivers do not support queueing more than one byte for
 435  * transfer, thus this function precisely implements their serial_puts().
 436  *
 437  * To optimize the number of get_current() calls, this function only
 438  * calls get_current() once and then directly accesses the putc() call
 439  * of the &struct serial_device .
 440  */
 441 void default_serial_puts(const char *s)
 442 {
 443         struct serial_device *dev = get_current();
 444         while (*s)
 445                 dev->putc(*s++);
 446 }
 447
 448 #if CONFIG_POST & CONFIG_SYS_POST_UART
 449 static const int bauds[] = CONFIG_SYS_BAUDRATE_TABLE;
 450
 451 /**
 452  * uart_post_test() - Test the currently selected serial port using POST
 453  * @flags:      POST framework flags
 454  *
 455  * Do a loopback test of the currently selected serial port. This
 456  * function is only useful in the context of the POST testing framwork.
 457  * The serial port is first configured into loopback mode and then
 458  * characters are sent through it.
 459  *
 460  * Returns 0 on success, value otherwise.
 461  */
 462 /* Mark weak until post/cpu/.../uart.c migrate over */
 463 __weak
 464 int uart_post_test(int flags)
 465 {
 466         unsigned char c;
 467         int ret, saved_baud, b;
 468         struct serial_device *saved_dev, *s;
 469
 470         /* Save current serial state */
 471         ret = 0;
 472         saved_dev = serial_current;
 473         saved_baud = gd->baudrate;
 474
 475         for (s = serial_devices; s; s = s->next) {
 476                 /* If this driver doesn't support loop back, skip it */
 477                 if (!s->loop)
 478                         continue;
 479
 480                 /* Test the next device */
 481                 serial_current = s;
 482
 483                 ret = serial_init();
 484                 if (ret)
 485                         goto done;
 486
 487                 /* Consume anything that happens to be queued */
 488                 while (serial_tstc())
 489                         serial_getc();
 490
 491                 /* Enable loop back */
 492                 s->loop(1);
 493
 494                 /* Test every available baud rate */
 495                 for (b = 0; b < ARRAY_SIZE(bauds); ++b) {
 496                         gd->baudrate = bauds[b];
 497                         serial_setbrg();
 498
 499                         /*
 500                          * Stick to printable chars to avoid issues:
 501                          *  - terminal corruption
 502                          *  - serial program reacting to sequences and sending
 503                          *    back random extra data
 504                          *  - most serial drivers add in extra chars (like \r\n)
 505                          */
 506                         for (c = 0x20; c < 0x7f; ++c) {
 507                                 /* Send it out */
 508                                 serial_putc(c);
 509
 510                                 /* Make sure it's the same one */
 511                                 ret = (c != serial_getc());
 512                                 if (ret) {
 513                                         s->loop(0);
 514                                         goto done;
 515                                 }
 516
 517                                 /* Clean up the output in case it was sent */
 518                                 serial_putc('\b');
 519                                 ret = ('\b' != serial_getc());
 520                                 if (ret) {
 521                                         s->loop(0);
 522                                         goto done;
 523                                 }
 524                         }
 525                 }
 526
 527                 /* Disable loop back */
 528                 s->loop(0);
 529
 530                 /* XXX: There is no serial_stop() !? */
 531                 if (s->stop)
 532                         s->stop();
 533         }
 534
 535  done:
 536         /* Restore previous serial state */
 537         serial_current = saved_dev;
 538         gd->baudrate = saved_baud;
 539         serial_reinit_all();
 540         serial_setbrg();
 541
 542         return ret;
 543 }
 544 #endif