uboot/drivers/serial/serial.c
<<
>>
Prefs
   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 <env_internal.h>
   9#include <hang.h>
  10#include <serial.h>
  11#include <stdio_dev.h>
  12#include <post.h>
  13#include <asm/global_data.h>
  14#include <linux/compiler.h>
  15#include <errno.h>
  16#include <linux/delay.h>
  17
  18DECLARE_GLOBAL_DATA_PTR;
  19
  20static struct serial_device *serial_devices;
  21static struct serial_device *serial_current;
  22/*
  23 * Table with supported baudrates (defined in config_xyz.h)
  24 */
  25static const unsigned long baudrate_table[] = CONFIG_SYS_BAUDRATE_TABLE;
  26
  27/**
  28 * serial_null() - Void registration routine of a serial driver
  29 *
  30 * This routine implements a void registration routine of a serial
  31 * driver. The registration routine of a particular driver is aliased
  32 * to this empty function in case the driver is not compiled into
  33 * U-Boot.
  34 */
  35static void serial_null(void)
  36{
  37}
  38
  39/**
  40 * on_baudrate() - Update the actual baudrate when the env var changes
  41 *
  42 * @name:       changed environment variable
  43 * @value:      new value of the environment variable
  44 * @op:         operation (create, overwrite, or delete)
  45 * @flags:      attributes of environment variable change,
  46 *              see flags H_* in include/search.h
  47 *
  48 * This will check for a valid baudrate and only apply it if valid.
  49 *
  50 * Return:      0 on success, 1 on error
  51 */
  52static int on_baudrate(const char *name, const char *value, enum env_op op,
  53        int flags)
  54{
  55        int i;
  56        int baudrate;
  57
  58        switch (op) {
  59        case env_op_create:
  60        case env_op_overwrite:
  61                /*
  62                 * Switch to new baudrate if new baudrate is supported
  63                 */
  64                baudrate = simple_strtoul(value, NULL, 10);
  65
  66                /* Not actually changing */
  67                if (gd->baudrate == baudrate)
  68                        return 0;
  69
  70                for (i = 0; i < ARRAY_SIZE(baudrate_table); ++i) {
  71                        if (baudrate == baudrate_table[i])
  72                                break;
  73                }
  74                if (i == ARRAY_SIZE(baudrate_table)) {
  75                        if ((flags & H_FORCE) == 0)
  76                                printf("## Baudrate %d bps not supported\n",
  77                                        baudrate);
  78                        return 1;
  79                }
  80                if ((flags & H_INTERACTIVE) != 0) {
  81                        printf("## Switch baudrate to %d"
  82                                " bps and press ENTER ...\n", baudrate);
  83                        udelay(50000);
  84                }
  85
  86                gd->baudrate = baudrate;
  87
  88                serial_setbrg();
  89
  90                udelay(50000);
  91
  92                if ((flags & H_INTERACTIVE) != 0)
  93                        while (1) {
  94                                if (getchar() == '\r')
  95                                        break;
  96                        }
  97
  98                return 0;
  99        case env_op_delete:
 100                printf("## Baudrate may not be deleted\n");
 101                return 1;
 102        default:
 103                return 0;
 104        }
 105}
 106U_BOOT_ENV_CALLBACK(baudrate, on_baudrate);
 107
 108/**
 109 * serial_initfunc() - Forward declare of driver registration routine
 110 * @name:       Name of the real driver registration routine.
 111 *
 112 * This macro expands onto forward declaration of a driver registration
 113 * routine, which is then used below in serial_initialize() function.
 114 * The declaration is made weak and aliases to serial_null() so in case
 115 * the driver is not compiled in, the function is still declared and can
 116 * be used, but aliases to serial_null() and thus is optimized away.
 117 */
 118#define serial_initfunc(name)                                   \
 119        void name(void)                                         \
 120                __attribute__((weak, alias("serial_null")));
 121
 122serial_initfunc(atmel_serial_initialize);
 123serial_initfunc(mcf_serial_initialize);
 124serial_initfunc(mpc85xx_serial_initialize);
 125serial_initfunc(mxc_serial_initialize);
 126serial_initfunc(ns16550_serial_initialize);
 127serial_initfunc(pl01x_serial_initialize);
 128serial_initfunc(pxa_serial_initialize);
 129serial_initfunc(sh_serial_initialize);
 130serial_initfunc(mtk_serial_initialize);
 131
 132/**
 133 * serial_register() - Register serial driver with serial driver core
 134 * @dev:        Pointer to the serial driver structure
 135 *
 136 * This function registers the serial driver supplied via @dev with
 137 * serial driver core, thus making U-Boot aware of it and making it
 138 * available for U-Boot to use. On platforms that still require manual
 139 * relocation of constant variables, relocation of the supplied structure
 140 * is performed.
 141 */
 142void serial_register(struct serial_device *dev)
 143{
 144#ifdef CONFIG_NEEDS_MANUAL_RELOC
 145        if (dev->start)
 146                dev->start += gd->reloc_off;
 147        if (dev->stop)
 148                dev->stop += gd->reloc_off;
 149        if (dev->setbrg)
 150                dev->setbrg += gd->reloc_off;
 151        if (dev->getc)
 152                dev->getc += gd->reloc_off;
 153        if (dev->tstc)
 154                dev->tstc += gd->reloc_off;
 155        if (dev->putc)
 156                dev->putc += gd->reloc_off;
 157        if (dev->puts)
 158                dev->puts += gd->reloc_off;
 159#endif
 160
 161        dev->next = serial_devices;
 162        serial_devices = dev;
 163}
 164
 165/**
 166 * serial_initialize() - Register all compiled-in serial port drivers
 167 *
 168 * This function registers all serial port drivers that are compiled
 169 * into the U-Boot binary with the serial core, thus making them
 170 * available to U-Boot to use. Lastly, this function assigns a default
 171 * serial port to the serial core. That serial port is then used as a
 172 * default output.
 173 */
 174int serial_initialize(void)
 175{
 176        atmel_serial_initialize();
 177        mcf_serial_initialize();
 178        mpc85xx_serial_initialize();
 179        mxc_serial_initialize();
 180        ns16550_serial_initialize();
 181        pl01x_serial_initialize();
 182        pxa_serial_initialize();
 183        sh_serial_initialize();
 184        mtk_serial_initialize();
 185
 186        serial_assign(default_serial_console()->name);
 187
 188        return 0;
 189}
 190
 191static int serial_stub_start(struct stdio_dev *sdev)
 192{
 193        struct serial_device *dev = sdev->priv;
 194
 195        return dev->start();
 196}
 197
 198static int serial_stub_stop(struct stdio_dev *sdev)
 199{
 200        struct serial_device *dev = sdev->priv;
 201
 202        return dev->stop();
 203}
 204
 205static void serial_stub_putc(struct stdio_dev *sdev, const char ch)
 206{
 207        struct serial_device *dev = sdev->priv;
 208
 209        dev->putc(ch);
 210}
 211
 212static void serial_stub_puts(struct stdio_dev *sdev, const char *str)
 213{
 214        struct serial_device *dev = sdev->priv;
 215
 216        dev->puts(str);
 217}
 218
 219static int serial_stub_getc(struct stdio_dev *sdev)
 220{
 221        struct serial_device *dev = sdev->priv;
 222
 223        return dev->getc();
 224}
 225
 226static int serial_stub_tstc(struct stdio_dev *sdev)
 227{
 228        struct serial_device *dev = sdev->priv;
 229
 230        return dev->tstc();
 231}
 232
 233/**
 234 * serial_stdio_init() - Register serial ports with STDIO core
 235 *
 236 * This function generates a proxy driver for each serial port driver.
 237 * These proxy drivers then register with the STDIO core, making the
 238 * serial drivers available as STDIO devices.
 239 */
 240void serial_stdio_init(void)
 241{
 242        struct stdio_dev dev;
 243        struct serial_device *s = serial_devices;
 244
 245        while (s) {
 246                memset(&dev, 0, sizeof(dev));
 247
 248                strcpy(dev.name, s->name);
 249                dev.flags = DEV_FLAGS_OUTPUT | DEV_FLAGS_INPUT;
 250
 251                dev.start = serial_stub_start;
 252                dev.stop = serial_stub_stop;
 253                dev.putc = serial_stub_putc;
 254                dev.puts = serial_stub_puts;
 255                dev.getc = serial_stub_getc;
 256                dev.tstc = serial_stub_tstc;
 257                dev.priv = s;
 258
 259                stdio_register(&dev);
 260
 261                s = s->next;
 262        }
 263}
 264
 265/**
 266 * serial_assign() - Select the serial output device by name
 267 * @name:       Name of the serial driver to be used as default output
 268 *
 269 * This function configures the serial output multiplexing by
 270 * selecting which serial device will be used as default. In case
 271 * the STDIO "serial" device is selected as stdin/stdout/stderr,
 272 * the serial device previously configured by this function will be
 273 * used for the particular operation.
 274 *
 275 * Returns 0 on success, negative on error.
 276 */
 277int serial_assign(const char *name)
 278{
 279        struct serial_device *s;
 280
 281        for (s = serial_devices; s; s = s->next) {
 282                if (strcmp(s->name, name))
 283                        continue;
 284                serial_current = s;
 285                return 0;
 286        }
 287
 288        return -EINVAL;
 289}
 290
 291/**
 292 * serial_reinit_all() - Reinitialize all compiled-in serial ports
 293 *
 294 * This function reinitializes all serial ports that are compiled
 295 * into U-Boot by calling their serial_start() functions.
 296 */
 297void serial_reinit_all(void)
 298{
 299        struct serial_device *s;
 300
 301        for (s = serial_devices; s; s = s->next)
 302                s->start();
 303}
 304
 305/**
 306 * get_current() - Return pointer to currently selected serial port
 307 *
 308 * This function returns a pointer to currently selected serial port.
 309 * The currently selected serial port is altered by serial_assign()
 310 * function.
 311 *
 312 * In case this function is called before relocation or before any serial
 313 * port is configured, this function calls default_serial_console() to
 314 * determine the serial port. Otherwise, the configured serial port is
 315 * returned.
 316 *
 317 * Returns pointer to the currently selected serial port on success,
 318 * NULL on error.
 319 */
 320static struct serial_device *get_current(void)
 321{
 322        struct serial_device *dev;
 323
 324        if (!(gd->flags & GD_FLG_RELOC))
 325                dev = default_serial_console();
 326        else if (!serial_current)
 327                dev = default_serial_console();
 328        else
 329                dev = serial_current;
 330
 331        /* We must have a console device */
 332        if (!dev) {
 333#ifdef CONFIG_SPL_BUILD
 334                puts("Cannot find console\n");
 335                hang();
 336#else
 337                panic("Cannot find console\n");
 338#endif
 339        }
 340
 341        return dev;
 342}
 343
 344/**
 345 * serial_init() - Initialize currently selected serial port
 346 *
 347 * This function initializes the currently selected serial port. This
 348 * usually involves setting up the registers of that particular port,
 349 * enabling clock and such. This function uses the get_current() call
 350 * to determine which port is selected.
 351 *
 352 * Returns 0 on success, negative on error.
 353 */
 354int serial_init(void)
 355{
 356        gd->flags |= GD_FLG_SERIAL_READY;
 357        return get_current()->start();
 358}
 359
 360/**
 361 * serial_setbrg() - Configure baud-rate of currently selected serial port
 362 *
 363 * This function configures the baud-rate of the currently selected
 364 * serial port. The baud-rate is retrieved from global data within
 365 * the serial port driver. This function uses the get_current() call
 366 * to determine which port is selected.
 367 *
 368 * Returns 0 on success, negative on error.
 369 */
 370void serial_setbrg(void)
 371{
 372        get_current()->setbrg();
 373}
 374
 375/**
 376 * serial_getc() - Read character from currently selected serial port
 377 *
 378 * This function retrieves a character from currently selected serial
 379 * port. In case there is no character waiting on the serial port,
 380 * this function will block and wait for the character to appear. This
 381 * function uses the get_current() call to determine which port is
 382 * selected.
 383 *
 384 * Returns the character on success, negative on error.
 385 */
 386int serial_getc(void)
 387{
 388        return get_current()->getc();
 389}
 390
 391/**
 392 * serial_tstc() - Test if data is available on currently selected serial port
 393 *
 394 * This function tests if one or more characters are available on
 395 * currently selected serial port. This function never blocks. This
 396 * function uses the get_current() call to determine which port is
 397 * selected.
 398 *
 399 * Returns positive if character is available, zero otherwise.
 400 */
 401int serial_tstc(void)
 402{
 403        return get_current()->tstc();
 404}
 405
 406/**
 407 * serial_putc() - Output character via currently selected serial port
 408 * @c:  Single character to be output from the serial port.
 409 *
 410 * This function outputs a character via currently selected serial
 411 * port. This character is passed to the serial port driver responsible
 412 * for controlling the hardware. The hardware may still be in process
 413 * of transmitting another character, therefore this function may block
 414 * for a short amount of time. This function uses the get_current()
 415 * call to determine which port is selected.
 416 */
 417void serial_putc(const char c)
 418{
 419        get_current()->putc(c);
 420}
 421
 422/**
 423 * serial_puts() - Output string via currently selected serial port
 424 * @s:  Zero-terminated string to be output from the serial port.
 425 *
 426 * This function outputs a zero-terminated string via currently
 427 * selected serial port. This function behaves as an accelerator
 428 * in case the hardware can queue multiple characters for transfer.
 429 * The whole string that is to be output is available to the function
 430 * implementing the hardware manipulation. Transmitting the whole
 431 * string may take some time, thus this function may block for some
 432 * amount of time. This function uses the get_current() call to
 433 * determine which port is selected.
 434 */
 435void serial_puts(const char *s)
 436{
 437        get_current()->puts(s);
 438}
 439
 440/**
 441 * default_serial_puts() - Output string by calling serial_putc() in loop
 442 * @s:  Zero-terminated string to be output from the serial port.
 443 *
 444 * This function outputs a zero-terminated string by calling serial_putc()
 445 * in a loop. Most drivers do not support queueing more than one byte for
 446 * transfer, thus this function precisely implements their serial_puts().
 447 *
 448 * To optimize the number of get_current() calls, this function only
 449 * calls get_current() once and then directly accesses the putc() call
 450 * of the &struct serial_device .
 451 */
 452void default_serial_puts(const char *s)
 453{
 454        struct serial_device *dev = get_current();
 455        while (*s)
 456                dev->putc(*s++);
 457}
 458
 459#if CONFIG_POST & CONFIG_SYS_POST_UART
 460static const int bauds[] = CONFIG_SYS_BAUDRATE_TABLE;
 461
 462/**
 463 * uart_post_test() - Test the currently selected serial port using POST
 464 * @flags:      POST framework flags
 465 *
 466 * Do a loopback test of the currently selected serial port. This
 467 * function is only useful in the context of the POST testing framwork.
 468 * The serial port is first configured into loopback mode and then
 469 * characters are sent through it.
 470 *
 471 * Returns 0 on success, value otherwise.
 472 */
 473/* Mark weak until post/cpu/.../uart.c migrate over */
 474__weak
 475int uart_post_test(int flags)
 476{
 477        unsigned char c;
 478        int ret, saved_baud, b;
 479        struct serial_device *saved_dev, *s;
 480
 481        /* Save current serial state */
 482        ret = 0;
 483        saved_dev = serial_current;
 484        saved_baud = gd->baudrate;
 485
 486        for (s = serial_devices; s; s = s->next) {
 487                /* If this driver doesn't support loop back, skip it */
 488                if (!s->loop)
 489                        continue;
 490
 491                /* Test the next device */
 492                serial_current = s;
 493
 494                ret = serial_init();
 495                if (ret)
 496                        goto done;
 497
 498                /* Consume anything that happens to be queued */
 499                while (serial_tstc())
 500                        serial_getc();
 501
 502                /* Enable loop back */
 503                s->loop(1);
 504
 505                /* Test every available baud rate */
 506                for (b = 0; b < ARRAY_SIZE(bauds); ++b) {
 507                        gd->baudrate = bauds[b];
 508                        serial_setbrg();
 509
 510                        /*
 511                         * Stick to printable chars to avoid issues:
 512                         *  - terminal corruption
 513                         *  - serial program reacting to sequences and sending
 514                         *    back random extra data
 515                         *  - most serial drivers add in extra chars (like \r\n)
 516                         */
 517                        for (c = 0x20; c < 0x7f; ++c) {
 518                                /* Send it out */
 519                                serial_putc(c);
 520
 521                                /* Make sure it's the same one */
 522                                ret = (c != serial_getc());
 523                                if (ret) {
 524                                        s->loop(0);
 525                                        goto done;
 526                                }
 527
 528                                /* Clean up the output in case it was sent */
 529                                serial_putc('\b');
 530                                ret = ('\b' != serial_getc());
 531                                if (ret) {
 532                                        s->loop(0);
 533                                        goto done;
 534                                }
 535                        }
 536                }
 537
 538                /* Disable loop back */
 539                s->loop(0);
 540
 541                /* XXX: There is no serial_stop() !? */
 542                if (s->stop)
 543                        s->stop();
 544        }
 545
 546 done:
 547        /* Restore previous serial state */
 548        serial_current = saved_dev;
 549        gd->baudrate = saved_baud;
 550        serial_reinit_all();
 551        serial_setbrg();
 552
 553        return ret;
 554}
 555#endif
 556