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
  78         if (CONFIG_IS_ENABLED(OF_PLATDATA)) {
  79                 uclass_first_device(UCLASS_SERIAL, &dev);
  80                 if (dev) {
  81                         gd->cur_serial_dev = dev;
  82                         return;
  83                 }
  84         } else if (CONFIG_IS_ENABLED(OF_CONTROL) && blob) {
  85                 /* Live tree has support for stdout */
  86                 if (of_live_active()) {
  87                         struct device_node *np = of_get_stdout();
  88
  89                         if (np && !uclass_get_device_by_ofnode(UCLASS_SERIAL,
  90                                         np_to_ofnode(np), &dev)) {
  91                                 gd->cur_serial_dev = dev;
  92                                 return;
  93                         }
  94                 } else {
  95                         if (!serial_check_stdout(blob, &dev)) {
  96                                 gd->cur_serial_dev = dev;
  97                                 return;
  98                         }
  99                 }
 100         }
 101         if (!SPL_BUILD || !CONFIG_IS_ENABLED(OF_CONTROL) || !blob) {
 102                 /*
 103                  * Try to use CONFIG_CONS_INDEX if available (it is numbered
 104                  * from 1!).
 105                  *
 106                  * Failing that, get the device with sequence number 0, or in
 107                  * extremis just the first serial device we can find. But we
 108                  * insist on having a console (even if it is silent).
 109                  */
 110 #ifdef CONFIG_CONS_INDEX
 111 #define INDEX (CONFIG_CONS_INDEX - 1)
 112 #else
 113 #define INDEX 0
 114 #endif
 115                 if (!uclass_get_device_by_seq(UCLASS_SERIAL, INDEX, &dev) ||
 116                     !uclass_get_device(UCLASS_SERIAL, INDEX, &dev) ||
 117                     (!uclass_first_device(UCLASS_SERIAL, &dev) && dev)) {
 118                         gd->cur_serial_dev = dev;
 119                         return;
 120                 }
 121 #undef INDEX
 122         }
 123
 124 #ifdef CONFIG_REQUIRE_SERIAL_CONSOLE
 125         panic_str("No serial driver found");
 126 #endif
 127 }
 128
 129 /* Called prior to relocation */
 130 int serial_init(void)
 131 {
 132         serial_find_console_or_panic();
 133         gd->flags |= GD_FLG_SERIAL_READY;
 134
 135         return 0;
 136 }
 137
 138 /* Called after relocation */
 139 void serial_initialize(void)
 140 {
 141         serial_init();
 142 }
 143
 144 static void _serial_putc(struct udevice *dev, char ch)
 145 {
 146         struct dm_serial_ops *ops = serial_get_ops(dev);
 147         int err;
 148
 149         if (ch == '\n')
 150                 _serial_putc(dev, '\r');
 151
 152         do {
 153                 err = ops->putc(dev, ch);
 154         } while (err == -EAGAIN);
 155 }
 156
 157 static void _serial_puts(struct udevice *dev, const char *str)
 158 {
 159         while (*str)
 160                 _serial_putc(dev, *str++);
 161 }
 162
 163 static int _serial_getc(struct udevice *dev)
 164 {
 165         struct dm_serial_ops *ops = serial_get_ops(dev);
 166         int err;
 167
 168         do {
 169                 err = ops->getc(dev);
 170                 if (err == -EAGAIN)
 171                         WATCHDOG_RESET();
 172         } while (err == -EAGAIN);
 173
 174         return err >= 0 ? err : 0;
 175 }
 176
 177 static int _serial_tstc(struct udevice *dev)
 178 {
 179         struct dm_serial_ops *ops = serial_get_ops(dev);
 180
 181         if (ops->pending)
 182                 return ops->pending(dev, true);
 183
 184         return 1;
 185 }
 186
 187 void serial_putc(char ch)
 188 {
 189         if (gd->cur_serial_dev)
 190                 _serial_putc(gd->cur_serial_dev, ch);
 191 }
 192
 193 void serial_puts(const char *str)
 194 {
 195         if (gd->cur_serial_dev)
 196                 _serial_puts(gd->cur_serial_dev, str);
 197 }
 198
 199 int serial_getc(void)
 200 {
 201         if (!gd->cur_serial_dev)
 202                 return 0;
 203
 204         return _serial_getc(gd->cur_serial_dev);
 205 }
 206
 207 int serial_tstc(void)
 208 {
 209         if (!gd->cur_serial_dev)
 210                 return 0;
 211
 212         return _serial_tstc(gd->cur_serial_dev);
 213 }
 214
 215 void serial_setbrg(void)
 216 {
 217         struct dm_serial_ops *ops;
 218
 219         if (!gd->cur_serial_dev)
 220                 return;
 221
 222         ops = serial_get_ops(gd->cur_serial_dev);
 223         if (ops->setbrg)
 224                 ops->setbrg(gd->cur_serial_dev, gd->baudrate);
 225 }
 226
 227 void serial_stdio_init(void)
 228 {
 229 }
 230
 231 #if defined(CONFIG_DM_STDIO)
 232
 233 #if CONFIG_IS_ENABLED(SERIAL_PRESENT)
 234 static void serial_stub_putc(struct stdio_dev *sdev, const char ch)
 235 {
 236         _serial_putc(sdev->priv, ch);
 237 }
 238 #endif
 239
 240 static void serial_stub_puts(struct stdio_dev *sdev, const char *str)
 241 {
 242         _serial_puts(sdev->priv, str);
 243 }
 244
 245 static int serial_stub_getc(struct stdio_dev *sdev)
 246 {
 247         return _serial_getc(sdev->priv);
 248 }
 249
 250 static int serial_stub_tstc(struct stdio_dev *sdev)
 251 {
 252         return _serial_tstc(sdev->priv);
 253 }
 254 #endif
 255
 256 /**
 257  * on_baudrate() - Update the actual baudrate when the env var changes
 258  *
 259  * This will check for a valid baudrate and only apply it if valid.
 260  */
 261 static int on_baudrate(const char *name, const char *value, enum env_op op,
 262         int flags)
 263 {
 264         int i;
 265         int baudrate;
 266
 267         switch (op) {
 268         case env_op_create:
 269         case env_op_overwrite:
 270                 /*
 271                  * Switch to new baudrate if new baudrate is supported
 272                  */
 273                 baudrate = simple_strtoul(value, NULL, 10);
 274
 275                 /* Not actually changing */
 276                 if (gd->baudrate == baudrate)
 277                         return 0;
 278
 279                 for (i = 0; i < ARRAY_SIZE(baudrate_table); ++i) {
 280                         if (baudrate == baudrate_table[i])
 281                                 break;
 282                 }
 283                 if (i == ARRAY_SIZE(baudrate_table)) {
 284                         if ((flags & H_FORCE) == 0)
 285                                 printf("## Baudrate %d bps not supported\n",
 286                                        baudrate);
 287                         return 1;
 288                 }
 289                 if ((flags & H_INTERACTIVE) != 0) {
 290                         printf("## Switch baudrate to %d bps and press ENTER ...\n",
 291                                baudrate);
 292                         udelay(50000);
 293                 }
 294
 295                 gd->baudrate = baudrate;
 296
 297                 serial_setbrg();
 298
 299                 udelay(50000);
 300
 301                 if ((flags & H_INTERACTIVE) != 0)
 302                         while (1) {
 303                                 if (getc() == '\r')
 304                                         break;
 305                         }
 306
 307                 return 0;
 308         case env_op_delete:
 309                 printf("## Baudrate may not be deleted\n");
 310                 return 1;
 311         default:
 312                 return 0;
 313         }
 314 }
 315 U_BOOT_ENV_CALLBACK(baudrate, on_baudrate);
 316
 317 #if CONFIG_IS_ENABLED(SERIAL_PRESENT)
 318 static int serial_post_probe(struct udevice *dev)
 319 {
 320         struct dm_serial_ops *ops = serial_get_ops(dev);
 321 #ifdef CONFIG_DM_STDIO
 322         struct serial_dev_priv *upriv = dev_get_uclass_priv(dev);
 323         struct stdio_dev sdev;
 324 #endif
 325         int ret;
 326
 327 #if defined(CONFIG_NEEDS_MANUAL_RELOC)
 328         if (ops->setbrg)
 329                 ops->setbrg += gd->reloc_off;
 330         if (ops->getc)
 331                 ops->getc += gd->reloc_off;
 332         if (ops->putc)
 333                 ops->putc += gd->reloc_off;
 334         if (ops->pending)
 335                 ops->pending += gd->reloc_off;
 336         if (ops->clear)
 337                 ops->clear += gd->reloc_off;
 338 #if CONFIG_POST & CONFIG_SYS_POST_UART
 339         if (ops->loop)
 340                 ops->loop += gd->reloc_off
 341 #endif
 342 #endif
 343         /* Set the baud rate */
 344         if (ops->setbrg) {
 345                 ret = ops->setbrg(dev, gd->baudrate);
 346                 if (ret)
 347                         return ret;
 348         }
 349
 350 #ifdef CONFIG_DM_STDIO
 351         if (!(gd->flags & GD_FLG_RELOC))
 352                 return 0;
 353         memset(&sdev, '\0', sizeof(sdev));
 354
 355         strncpy(sdev.name, dev->name, sizeof(sdev.name));
 356         sdev.flags = DEV_FLAGS_OUTPUT | DEV_FLAGS_INPUT;
 357         sdev.priv = dev;
 358         sdev.putc = serial_stub_putc;
 359         sdev.puts = serial_stub_puts;
 360         sdev.getc = serial_stub_getc;
 361         sdev.tstc = serial_stub_tstc;
 362         stdio_register_dev(&sdev, &upriv->sdev);
 363 #endif
 364         return 0;
 365 }
 366
 367 static int serial_pre_remove(struct udevice *dev)
 368 {
 369 #if CONFIG_IS_ENABLED(SYS_STDIO_DEREGISTER)
 370         struct serial_dev_priv *upriv = dev_get_uclass_priv(dev);
 371
 372         if (stdio_deregister_dev(upriv->sdev, true))
 373                 return -EPERM;
 374 #endif
 375
 376         return 0;
 377 }
 378
 379 UCLASS_DRIVER(serial) = {
 380         .id             = UCLASS_SERIAL,
 381         .name           = "serial",
 382         .flags          = DM_UC_FLAG_SEQ_ALIAS,
 383         .post_probe     = serial_post_probe,
 384         .pre_remove     = serial_pre_remove,
 385         .per_device_auto_alloc_size = sizeof(struct serial_dev_priv),
 386 };
 387 #endif