drivers/serial/serial-uclass.c

   1 /*
   2  * Copyright (c) 2014 The Chromium OS Authors.
   3  *
   4  * SPDX-License-Identifier:     GPL-2.0+
   5  */
   6
   7 #include <common.h>
   8 #include <dm.h>
   9 #include <environment.h>
  10 #include <errno.h>
  11 #include <os.h>
  12 #include <serial.h>
  13 #include <stdio_dev.h>
  14 #include <watchdog.h>
  15 #include <dm/lists.h>
  16 #include <dm/device-internal.h>
  17 #include <dm/of_access.h>
  18
  19 DECLARE_GLOBAL_DATA_PTR;
  20
  21 /*
  22  * Table with supported baudrates (defined in config_xyz.h)
  23  */
  24 static const unsigned long baudrate_table[] = CONFIG_SYS_BAUDRATE_TABLE;
  25
  26 #if !CONFIG_VAL(SYS_MALLOC_F_LEN)
  27 #error "Serial is required before relocation - define CONFIG_$(SPL_)SYS_MALLOC_F_LEN to make this work"
  28 #endif
  29
  30 static int serial_check_stdout(const void *blob, struct udevice **devp)
  31 {
  32         int node;
  33
  34         /* Check for a chosen console */
  35         node = fdtdec_get_chosen_node(blob, "stdout-path");
  36         if (node < 0) {
  37                 const char *str, *p, *name;
  38
  39                 /*
  40                  * Deal with things like
  41                  *      stdout-path = "serial0:115200n8";
  42                  *
  43                  * We need to look up the alias and then follow it to the
  44                  * correct node.
  45                  */
  46                 str = fdtdec_get_chosen_prop(blob, "stdout-path");
  47                 if (str) {
  48                         p = strchr(str, ':');
  49                         name = fdt_get_alias_namelen(blob, str,
  50                                         p ? p - str : strlen(str));
  51                         if (name)
  52                                 node = fdt_path_offset(blob, name);
  53                 }
  54         }
  55         if (node < 0)
  56                 node = fdt_path_offset(blob, "console");
  57         if (!uclass_get_device_by_of_offset(UCLASS_SERIAL, node, devp))
  58                 return 0;
  59
  60         /*
  61          * If the console is not marked to be bound before relocation, bind it
  62          * anyway.
  63          */
  64         if (node > 0 && !lists_bind_fdt(gd->dm_root, offset_to_ofnode(node),
  65                                         devp)) {
  66                 if (!device_probe(*devp))
  67                         return 0;
  68         }
  69
  70         return -ENODEV;
  71 }
  72
  73 static void serial_find_console_or_panic(void)
  74 {
  75         const void *blob = gd->fdt_blob;
  76         struct udevice *dev;
  77         int ret;
  78
  79         if (CONFIG_IS_ENABLED(OF_PLATDATA)) {
  80                 uclass_first_device(UCLASS_SERIAL, &dev);
  81                 if (dev) {
  82                         gd->cur_serial_dev = dev;
  83                         return;
  84                 }
  85         } else if (CONFIG_IS_ENABLED(OF_CONTROL) && blob) {
  86                 /* Live tree has support for stdout */
  87                 if (of_live_active()) {
  88                         struct device_node *np = of_get_stdout();
  89
  90                         if (np && !uclass_get_device_by_ofnode(UCLASS_SERIAL,
  91                                         np_to_ofnode(np), &dev)) {
  92                                 gd->cur_serial_dev = dev;
  93                                 return;
  94                         }
  95                 } else {
  96                         if (!serial_check_stdout(blob, &dev)) {
  97                                 gd->cur_serial_dev = dev;
  98                                 return;
  99                         }
 100                 }
 101         }
 102         if (!SPL_BUILD || !CONFIG_IS_ENABLED(OF_CONTROL) || !blob) {
 103                 /*
 104                  * Try to use CONFIG_CONS_INDEX if available (it is numbered
 105                  * from 1!).
 106                  *
 107                  * Failing that, get the device with sequence number 0, or in
 108                  * extremis just the first working serial device we can find.
 109                  * But we insist on having a console (even if it is silent).
 110                  */
 111 #ifdef CONFIG_CONS_INDEX
 112 #define INDEX (CONFIG_CONS_INDEX - 1)
 113 #else
 114 #define INDEX 0
 115 #endif
 116                 if (!uclass_get_device_by_seq(UCLASS_SERIAL, INDEX, &dev) ||
 117                     !uclass_get_device(UCLASS_SERIAL, INDEX, &dev)) {
 118                         if (dev->flags & DM_FLAG_ACTIVATED) {
 119                                 gd->cur_serial_dev = dev;
 120                                 return;
 121                         }
 122                 }
 123
 124                 /* Search for any working device */
 125                 for (ret = uclass_first_device_check(UCLASS_SERIAL, &dev);
 126                      dev;
 127                      ret = uclass_next_device_check(&dev)) {
 128                         if (!ret) {
 129                                 /* Device did succeed probing */
 130                                 gd->cur_serial_dev = dev;
 131                                 return;
 132                         }
 133                 }
 134 #undef INDEX
 135         }
 136
 137 #ifdef CONFIG_REQUIRE_SERIAL_CONSOLE
 138         panic_str("No serial driver found");
 139 #endif
 140 }
 141
 142 /* Called prior to relocation */
 143 int serial_init(void)
 144 {
 145         serial_find_console_or_panic();
 146         gd->flags |= GD_FLG_SERIAL_READY;
 147
 148         return 0;
 149 }
 150
 151 /* Called after relocation */
 152 void serial_initialize(void)
 153 {
 154         serial_init();
 155 }
 156
 157 static void _serial_putc(struct udevice *dev, char ch)
 158 {
 159         struct dm_serial_ops *ops = serial_get_ops(dev);
 160         int err;
 161
 162         if (ch == '\n')
 163                 _serial_putc(dev, '\r');
 164
 165         do {
 166                 err = ops->putc(dev, ch);
 167         } while (err == -EAGAIN);
 168 }
 169
 170 static void _serial_puts(struct udevice *dev, const char *str)
 171 {
 172         while (*str)
 173                 _serial_putc(dev, *str++);
 174 }
 175
 176 static int __serial_getc(struct udevice *dev)
 177 {
 178         struct dm_serial_ops *ops = serial_get_ops(dev);
 179         int err;
 180
 181         do {
 182                 err = ops->getc(dev);
 183                 if (err == -EAGAIN)
 184                         WATCHDOG_RESET();
 185         } while (err == -EAGAIN);
 186
 187         return err >= 0 ? err : 0;
 188 }
 189
 190 static int __serial_tstc(struct udevice *dev)
 191 {
 192         struct dm_serial_ops *ops = serial_get_ops(dev);
 193
 194         if (ops->pending)
 195                 return ops->pending(dev, true);
 196
 197         return 1;
 198 }
 199
 200 #if CONFIG_IS_ENABLED(SERIAL_RX_BUFFER)
 201 static int _serial_tstc(struct udevice *dev)
 202 {
 203         struct serial_dev_priv *upriv = dev_get_uclass_priv(dev);
 204
 205         /* Read all available chars into the RX buffer */
 206         while (__serial_tstc(dev)) {
 207                 upriv->buf[upriv->wr_ptr++] = __serial_getc(dev);
 208                 upriv->wr_ptr %= CONFIG_SERIAL_RX_BUFFER_SIZE;
 209         }
 210
 211         return upriv->rd_ptr != upriv->wr_ptr ? 1 : 0;
 212 }
 213
 214 static int _serial_getc(struct udevice *dev)
 215 {
 216         struct serial_dev_priv *upriv = dev_get_uclass_priv(dev);
 217         char val;
 218
 219         val = upriv->buf[upriv->rd_ptr++];
 220         upriv->rd_ptr %= CONFIG_SERIAL_RX_BUFFER_SIZE;
 221
 222         return val;
 223 }
 224
 225 #else /* CONFIG_IS_ENABLED(SERIAL_RX_BUFFER) */
 226
 227 static int _serial_getc(struct udevice *dev)
 228 {
 229         return __serial_getc(dev);
 230 }
 231
 232 static int _serial_tstc(struct udevice *dev)
 233 {
 234         return __serial_tstc(dev);
 235 }
 236 #endif /* CONFIG_IS_ENABLED(SERIAL_RX_BUFFER) */
 237
 238 void serial_putc(char ch)
 239 {
 240         if (gd->cur_serial_dev)
 241                 _serial_putc(gd->cur_serial_dev, ch);
 242 }
 243
 244 void serial_puts(const char *str)
 245 {
 246         if (gd->cur_serial_dev)
 247                 _serial_puts(gd->cur_serial_dev, str);
 248 }
 249
 250 int serial_getc(void)
 251 {
 252         if (!gd->cur_serial_dev)
 253                 return 0;
 254
 255         return _serial_getc(gd->cur_serial_dev);
 256 }
 257
 258 int serial_tstc(void)
 259 {
 260         if (!gd->cur_serial_dev)
 261                 return 0;
 262
 263         return _serial_tstc(gd->cur_serial_dev);
 264 }
 265
 266 void serial_setbrg(void)
 267 {
 268         struct dm_serial_ops *ops;
 269
 270         if (!gd->cur_serial_dev)
 271                 return;
 272
 273         ops = serial_get_ops(gd->cur_serial_dev);
 274         if (ops->setbrg)
 275                 ops->setbrg(gd->cur_serial_dev, gd->baudrate);
 276 }
 277
 278 void serial_stdio_init(void)
 279 {
 280 }
 281
 282 #if defined(CONFIG_DM_STDIO)
 283
 284 #if CONFIG_IS_ENABLED(SERIAL_PRESENT)
 285 static void serial_stub_putc(struct stdio_dev *sdev, const char ch)
 286 {
 287         _serial_putc(sdev->priv, ch);
 288 }
 289 #endif
 290
 291 static void serial_stub_puts(struct stdio_dev *sdev, const char *str)
 292 {
 293         _serial_puts(sdev->priv, str);
 294 }
 295
 296 static int serial_stub_getc(struct stdio_dev *sdev)
 297 {
 298         return _serial_getc(sdev->priv);
 299 }
 300
 301 static int serial_stub_tstc(struct stdio_dev *sdev)
 302 {
 303         return _serial_tstc(sdev->priv);
 304 }
 305 #endif
 306
 307 /**
 308  * on_baudrate() - Update the actual baudrate when the env var changes
 309  *
 310  * This will check for a valid baudrate and only apply it if valid.
 311  */
 312 static int on_baudrate(const char *name, const char *value, enum env_op op,
 313         int flags)
 314 {
 315         int i;
 316         int baudrate;
 317
 318         switch (op) {
 319         case env_op_create:
 320         case env_op_overwrite:
 321                 /*
 322                  * Switch to new baudrate if new baudrate is supported
 323                  */
 324                 baudrate = simple_strtoul(value, NULL, 10);
 325
 326                 /* Not actually changing */
 327                 if (gd->baudrate == baudrate)
 328                         return 0;
 329
 330                 for (i = 0; i < ARRAY_SIZE(baudrate_table); ++i) {
 331                         if (baudrate == baudrate_table[i])
 332                                 break;
 333                 }
 334                 if (i == ARRAY_SIZE(baudrate_table)) {
 335                         if ((flags & H_FORCE) == 0)
 336                                 printf("## Baudrate %d bps not supported\n",
 337                                        baudrate);
 338                         return 1;
 339                 }
 340                 if ((flags & H_INTERACTIVE) != 0) {
 341                         printf("## Switch baudrate to %d bps and press ENTER ...\n",
 342                                baudrate);
 343                         udelay(50000);
 344                 }
 345
 346                 gd->baudrate = baudrate;
 347
 348                 serial_setbrg();
 349
 350                 udelay(50000);
 351
 352                 if ((flags & H_INTERACTIVE) != 0)
 353                         while (1) {
 354                                 if (getc() == '\r')
 355                                         break;
 356                         }
 357
 358                 return 0;
 359         case env_op_delete:
 360                 printf("## Baudrate may not be deleted\n");
 361                 return 1;
 362         default:
 363                 return 0;
 364         }
 365 }
 366 U_BOOT_ENV_CALLBACK(baudrate, on_baudrate);
 367
 368 #if CONFIG_IS_ENABLED(SERIAL_PRESENT)
 369 static int serial_post_probe(struct udevice *dev)
 370 {
 371         struct dm_serial_ops *ops = serial_get_ops(dev);
 372 #ifdef CONFIG_DM_STDIO
 373         struct serial_dev_priv *upriv = dev_get_uclass_priv(dev);
 374         struct stdio_dev sdev;
 375 #endif
 376         int ret;
 377
 378 #if defined(CONFIG_NEEDS_MANUAL_RELOC)
 379         if (ops->setbrg)
 380                 ops->setbrg += gd->reloc_off;
 381         if (ops->getc)
 382                 ops->getc += gd->reloc_off;
 383         if (ops->putc)
 384                 ops->putc += gd->reloc_off;
 385         if (ops->pending)
 386                 ops->pending += gd->reloc_off;
 387         if (ops->clear)
 388                 ops->clear += gd->reloc_off;
 389 #if CONFIG_POST & CONFIG_SYS_POST_UART
 390         if (ops->loop)
 391                 ops->loop += gd->reloc_off
 392 #endif
 393 #endif
 394         /* Set the baud rate */
 395         if (ops->setbrg) {
 396                 ret = ops->setbrg(dev, gd->baudrate);
 397                 if (ret)
 398                         return ret;
 399         }
 400
 401 #ifdef CONFIG_DM_STDIO
 402         if (!(gd->flags & GD_FLG_RELOC))
 403                 return 0;
 404         memset(&sdev, '\0', sizeof(sdev));
 405
 406         strncpy(sdev.name, dev->name, sizeof(sdev.name));
 407         sdev.flags = DEV_FLAGS_OUTPUT | DEV_FLAGS_INPUT | DEV_FLAGS_DM;
 408         sdev.priv = dev;
 409         sdev.putc = serial_stub_putc;
 410         sdev.puts = serial_stub_puts;
 411         sdev.getc = serial_stub_getc;
 412         sdev.tstc = serial_stub_tstc;
 413
 414 #if CONFIG_IS_ENABLED(SERIAL_RX_BUFFER)
 415         /* Allocate the RX buffer */
 416         upriv->buf = malloc(CONFIG_SERIAL_RX_BUFFER_SIZE);
 417 #endif
 418
 419         stdio_register_dev(&sdev, &upriv->sdev);
 420 #endif
 421         return 0;
 422 }
 423
 424 static int serial_pre_remove(struct udevice *dev)
 425 {
 426 #if CONFIG_IS_ENABLED(SYS_STDIO_DEREGISTER)
 427         struct serial_dev_priv *upriv = dev_get_uclass_priv(dev);
 428
 429         if (stdio_deregister_dev(upriv->sdev, true))
 430                 return -EPERM;
 431 #endif
 432
 433         return 0;
 434 }
 435
 436 UCLASS_DRIVER(serial) = {
 437         .id             = UCLASS_SERIAL,
 438         .name           = "serial",
 439         .flags          = DM_UC_FLAG_SEQ_ALIAS,
 440         .post_probe     = serial_post_probe,
 441         .pre_remove     = serial_pre_remove,
 442         .per_device_auto_alloc_size = sizeof(struct serial_dev_priv),
 443 };
 444 #endif