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 <fdtdec.h>
  12 #include <os.h>
  13 #include <serial.h>
  14 #include <stdio_dev.h>
  15 #include <watchdog.h>
  16 #include <dm/lists.h>
  17 #include <dm/device-internal.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 #ifndef CONFIG_SYS_MALLOC_F_LEN
  27 #error "Serial is required before relocation - define CONFIG_SYS_MALLOC_F_LEN to make this work"
  28 #endif
  29
  30 static void serial_find_console_or_panic(void)
  31 {
  32         struct udevice *dev;
  33
  34 #ifdef CONFIG_OF_CONTROL
  35         int node;
  36
  37         /* Check for a chosen console */
  38         node = fdtdec_get_chosen_node(gd->fdt_blob, "stdout-path");
  39         if (node < 0)
  40                 node = fdt_path_offset(gd->fdt_blob, "console");
  41         if (!uclass_get_device_by_of_offset(UCLASS_SERIAL, node, &dev)) {
  42                 gd->cur_serial_dev = dev;
  43                 return;
  44         }
  45
  46         /*
  47          * If the console is not marked to be bound before relocation, bind
  48          * it anyway.
  49          */
  50         if (node > 0 &&
  51             !lists_bind_fdt(gd->dm_root, gd->fdt_blob, node, &dev)) {
  52                 if (!device_probe(dev)) {
  53                         gd->cur_serial_dev = dev;
  54                         return;
  55                 }
  56         }
  57 #endif
  58         /*
  59          * Try to use CONFIG_CONS_INDEX if available (it is numbered from 1!).
  60          *
  61          * Failing that, get the device with sequence number 0, or in extremis
  62          * just the first serial device we can find. But we insist on having
  63          * a console (even if it is silent).
  64          */
  65 #ifdef CONFIG_CONS_INDEX
  66 #define INDEX (CONFIG_CONS_INDEX - 1)
  67 #else
  68 #define INDEX 0
  69 #endif
  70         if (uclass_get_device_by_seq(UCLASS_SERIAL, INDEX, &dev) &&
  71             uclass_get_device(UCLASS_SERIAL, INDEX, &dev) &&
  72             (uclass_first_device(UCLASS_SERIAL, &dev) || !dev))
  73                 panic("No serial driver found");
  74 #undef INDEX
  75         gd->cur_serial_dev = dev;
  76 }
  77
  78 /* Called prior to relocation */
  79 int serial_init(void)
  80 {
  81         serial_find_console_or_panic();
  82         gd->flags |= GD_FLG_SERIAL_READY;
  83
  84         return 0;
  85 }
  86
  87 /* Called after relocation */
  88 void serial_initialize(void)
  89 {
  90         serial_find_console_or_panic();
  91 }
  92
  93 static void _serial_putc(struct udevice *dev, char ch)
  94 {
  95         struct dm_serial_ops *ops = serial_get_ops(dev);
  96         int err;
  97
  98         do {
  99                 err = ops->putc(dev, ch);
 100         } while (err == -EAGAIN);
 101         if (ch == '\n')
 102                 _serial_putc(dev, '\r');
 103 }
 104
 105 static void _serial_puts(struct udevice *dev, const char *str)
 106 {
 107         while (*str)
 108                 _serial_putc(dev, *str++);
 109 }
 110
 111 static int _serial_getc(struct udevice *dev)
 112 {
 113         struct dm_serial_ops *ops = serial_get_ops(dev);
 114         int err;
 115
 116         do {
 117                 err = ops->getc(dev);
 118                 if (err == -EAGAIN)
 119                         WATCHDOG_RESET();
 120         } while (err == -EAGAIN);
 121
 122         return err >= 0 ? err : 0;
 123 }
 124
 125 static int _serial_tstc(struct udevice *dev)
 126 {
 127         struct dm_serial_ops *ops = serial_get_ops(dev);
 128
 129         if (ops->pending)
 130                 return ops->pending(dev, true);
 131
 132         return 1;
 133 }
 134
 135 void serial_putc(char ch)
 136 {
 137         _serial_putc(gd->cur_serial_dev, ch);
 138 }
 139
 140 void serial_puts(const char *str)
 141 {
 142         _serial_puts(gd->cur_serial_dev, str);
 143 }
 144
 145 int serial_getc(void)
 146 {
 147         return _serial_getc(gd->cur_serial_dev);
 148 }
 149
 150 int serial_tstc(void)
 151 {
 152         return _serial_tstc(gd->cur_serial_dev);
 153 }
 154
 155 void serial_setbrg(void)
 156 {
 157         struct dm_serial_ops *ops = serial_get_ops(gd->cur_serial_dev);
 158
 159         if (ops->setbrg)
 160                 ops->setbrg(gd->cur_serial_dev, gd->baudrate);
 161 }
 162
 163 void serial_stdio_init(void)
 164 {
 165 }
 166
 167 #ifdef CONFIG_DM_STDIO
 168 static void serial_stub_putc(struct stdio_dev *sdev, const char ch)
 169 {
 170         _serial_putc(sdev->priv, ch);
 171 }
 172 #endif
 173
 174 void serial_stub_puts(struct stdio_dev *sdev, const char *str)
 175 {
 176         _serial_puts(sdev->priv, str);
 177 }
 178
 179 int serial_stub_getc(struct stdio_dev *sdev)
 180 {
 181         return _serial_getc(sdev->priv);
 182 }
 183
 184 int serial_stub_tstc(struct stdio_dev *sdev)
 185 {
 186         return _serial_tstc(sdev->priv);
 187 }
 188
 189 /**
 190  * on_baudrate() - Update the actual baudrate when the env var changes
 191  *
 192  * This will check for a valid baudrate and only apply it if valid.
 193  */
 194 static int on_baudrate(const char *name, const char *value, enum env_op op,
 195         int flags)
 196 {
 197         int i;
 198         int baudrate;
 199
 200         switch (op) {
 201         case env_op_create:
 202         case env_op_overwrite:
 203                 /*
 204                  * Switch to new baudrate if new baudrate is supported
 205                  */
 206                 baudrate = simple_strtoul(value, NULL, 10);
 207
 208                 /* Not actually changing */
 209                 if (gd->baudrate == baudrate)
 210                         return 0;
 211
 212                 for (i = 0; i < ARRAY_SIZE(baudrate_table); ++i) {
 213                         if (baudrate == baudrate_table[i])
 214                                 break;
 215                 }
 216                 if (i == ARRAY_SIZE(baudrate_table)) {
 217                         if ((flags & H_FORCE) == 0)
 218                                 printf("## Baudrate %d bps not supported\n",
 219                                        baudrate);
 220                         return 1;
 221                 }
 222                 if ((flags & H_INTERACTIVE) != 0) {
 223                         printf("## Switch baudrate to %d bps and press ENTER ...\n",
 224                                baudrate);
 225                         udelay(50000);
 226                 }
 227
 228                 gd->baudrate = baudrate;
 229
 230                 serial_setbrg();
 231
 232                 udelay(50000);
 233
 234                 if ((flags & H_INTERACTIVE) != 0)
 235                         while (1) {
 236                                 if (getc() == '\r')
 237                                         break;
 238                         }
 239
 240                 return 0;
 241         case env_op_delete:
 242                 printf("## Baudrate may not be deleted\n");
 243                 return 1;
 244         default:
 245                 return 0;
 246         }
 247 }
 248 U_BOOT_ENV_CALLBACK(baudrate, on_baudrate);
 249
 250 static int serial_post_probe(struct udevice *dev)
 251 {
 252         struct dm_serial_ops *ops = serial_get_ops(dev);
 253 #ifdef CONFIG_DM_STDIO
 254         struct serial_dev_priv *upriv = dev_get_uclass_priv(dev);
 255         struct stdio_dev sdev;
 256 #endif
 257         int ret;
 258
 259 #if defined(CONFIG_NEEDS_MANUAL_RELOC)
 260         if (ops->setbrg)
 261                 ops->setbrg += gd->reloc_off;
 262         if (ops->getc)
 263                 ops->getc += gd->reloc_off;
 264         if (ops->putc)
 265                 ops->putc += gd->reloc_off;
 266         if (ops->pending)
 267                 ops->pending += gd->reloc_off;
 268         if (ops->clear)
 269                 ops->clear += gd->reloc_off;
 270 #if CONFIG_POST & CONFIG_SYS_POST_UART
 271         if (ops->loop)
 272                 ops->loop += gd->reloc_off
 273 #endif
 274 #endif
 275         /* Set the baud rate */
 276         if (ops->setbrg) {
 277                 ret = ops->setbrg(dev, gd->baudrate);
 278                 if (ret)
 279                         return ret;
 280         }
 281
 282 #ifdef CONFIG_DM_STDIO
 283         if (!(gd->flags & GD_FLG_RELOC))
 284                 return 0;
 285         memset(&sdev, '\0', sizeof(sdev));
 286
 287         strncpy(sdev.name, dev->name, sizeof(sdev.name));
 288         sdev.flags = DEV_FLAGS_OUTPUT | DEV_FLAGS_INPUT;
 289         sdev.priv = dev;
 290         sdev.putc = serial_stub_putc;
 291         sdev.puts = serial_stub_puts;
 292         sdev.getc = serial_stub_getc;
 293         sdev.tstc = serial_stub_tstc;
 294         stdio_register_dev(&sdev, &upriv->sdev);
 295 #endif
 296         return 0;
 297 }
 298
 299 static int serial_pre_remove(struct udevice *dev)
 300 {
 301 #ifdef CONFIG_SYS_STDIO_DEREGISTER
 302         struct serial_dev_priv *upriv = dev_get_uclass_priv(dev);
 303
 304         if (stdio_deregister_dev(upriv->sdev, 0))
 305                 return -EPERM;
 306 #endif
 307
 308         return 0;
 309 }
 310
 311 UCLASS_DRIVER(serial) = {
 312         .id             = UCLASS_SERIAL,
 313         .name           = "serial",
 314         .flags          = DM_UC_FLAG_SEQ_ALIAS,
 315         .post_probe     = serial_post_probe,
 316         .pre_remove     = serial_pre_remove,
 317         .per_device_auto_alloc_size = sizeof(struct serial_dev_priv),
 318 };