include/linux/serial_core.h

   1 /*
   2  *  linux/drivers/char/serial_core.h
   3  *
   4  *  Copyright (C) 2000 Deep Blue Solutions Ltd.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20 #ifndef LINUX_SERIAL_CORE_H
  21 #define LINUX_SERIAL_CORE_H
  22
  23 #include <linux/bitops.h>
  24 #include <linux/compiler.h>
  25 #include <linux/interrupt.h>
  26 #include <linux/circ_buf.h>
  27 #include <linux/spinlock.h>
  28 #include <linux/sched.h>
  29 #include <linux/tty.h>
  30 #include <linux/mutex.h>
  31 #include <linux/sysrq.h>
  32 #include <uapi/linux/serial_core.h>
  33
  34 #ifdef CONFIG_SERIAL_CORE_CONSOLE
  35 #define uart_console(port) \
  36         ((port)->cons && (port)->cons->index == (port)->line)
  37 #else
  38 #define uart_console(port)      ({ (void)port; 0; })
  39 #endif
  40
  41 struct uart_port;
  42 struct serial_struct;
  43 struct device;
  44
  45 /*
  46  * This structure describes all the operations that can be done on the
  47  * physical hardware.  See Documentation/serial/driver for details.
  48  */
  49 struct uart_ops {
  50         unsigned int    (*tx_empty)(struct uart_port *);
  51         void            (*set_mctrl)(struct uart_port *, unsigned int mctrl);
  52         unsigned int    (*get_mctrl)(struct uart_port *);
  53         void            (*stop_tx)(struct uart_port *);
  54         void            (*start_tx)(struct uart_port *);
  55         void            (*throttle)(struct uart_port *);
  56         void            (*unthrottle)(struct uart_port *);
  57         void            (*send_xchar)(struct uart_port *, char ch);
  58         void            (*stop_rx)(struct uart_port *);
  59         void            (*enable_ms)(struct uart_port *);
  60         void            (*break_ctl)(struct uart_port *, int ctl);
  61         int             (*startup)(struct uart_port *);
  62         void            (*shutdown)(struct uart_port *);
  63         void            (*flush_buffer)(struct uart_port *);
  64         void            (*set_termios)(struct uart_port *, struct ktermios *new,
  65                                        struct ktermios *old);
  66         void            (*set_ldisc)(struct uart_port *, struct ktermios *);
  67         void            (*pm)(struct uart_port *, unsigned int state,
  68                               unsigned int oldstate);
  69
  70         /*
  71          * Return a string describing the type of the port
  72          */
  73         const char      *(*type)(struct uart_port *);
  74
  75         /*
  76          * Release IO and memory resources used by the port.
  77          * This includes iounmap if necessary.
  78          */
  79         void            (*release_port)(struct uart_port *);
  80
  81         /*
  82          * Request IO and memory resources used by the port.
  83          * This includes iomapping the port if necessary.
  84          */
  85         int             (*request_port)(struct uart_port *);
  86         void            (*config_port)(struct uart_port *, int);
  87         int             (*verify_port)(struct uart_port *, struct serial_struct *);
  88         int             (*ioctl)(struct uart_port *, unsigned int, unsigned long);
  89 #ifdef CONFIG_CONSOLE_POLL
  90         int             (*poll_init)(struct uart_port *);
  91         void            (*poll_put_char)(struct uart_port *, unsigned char);
  92         int             (*poll_get_char)(struct uart_port *);
  93 #endif
  94 };
  95
  96 #define NO_POLL_CHAR            0x00ff0000
  97 #define UART_CONFIG_TYPE        (1 << 0)
  98 #define UART_CONFIG_IRQ         (1 << 1)
  99
 100 struct uart_icount {
 101         __u32   cts;
 102         __u32   dsr;
 103         __u32   rng;
 104         __u32   dcd;
 105         __u32   rx;
 106         __u32   tx;
 107         __u32   frame;
 108         __u32   overrun;
 109         __u32   parity;
 110         __u32   brk;
 111         __u32   buf_overrun;
 112 };
 113
 114 typedef unsigned int __bitwise upf_t;
 115 typedef unsigned int __bitwise upstat_t;
 116
 117 struct uart_port {
 118         spinlock_t              lock;                   /* port lock */
 119         unsigned long           iobase;                 /* in/out[bwl] */
 120         unsigned char __iomem   *membase;               /* read/write[bwl] */
 121         unsigned int            (*serial_in)(struct uart_port *, int);
 122         void                    (*serial_out)(struct uart_port *, int, int);
 123         void                    (*set_termios)(struct uart_port *,
 124                                                struct ktermios *new,
 125                                                struct ktermios *old);
 126         void                    (*set_ldisc)(struct uart_port *,
 127                                              struct ktermios *);
 128         unsigned int            (*get_mctrl)(struct uart_port *);
 129         void                    (*set_mctrl)(struct uart_port *, unsigned int);
 130         int                     (*startup)(struct uart_port *port);
 131         void                    (*shutdown)(struct uart_port *port);
 132         void                    (*throttle)(struct uart_port *port);
 133         void                    (*unthrottle)(struct uart_port *port);
 134         int                     (*handle_irq)(struct uart_port *);
 135         void                    (*pm)(struct uart_port *, unsigned int state,
 136                                       unsigned int old);
 137         void                    (*handle_break)(struct uart_port *);
 138         int                     (*rs485_config)(struct uart_port *,
 139                                                 struct serial_rs485 *rs485);
 140         unsigned int            irq;                    /* irq number */
 141         unsigned long           irqflags;               /* irq flags  */
 142         unsigned int            uartclk;                /* base uart clock */
 143         unsigned int            fifosize;               /* tx fifo size */
 144         unsigned char           x_char;                 /* xon/xoff char */
 145         unsigned char           regshift;               /* reg offset shift */
 146         unsigned char           iotype;                 /* io access style */
 147         unsigned char           quirks;                 /* internal quirks */
 148
 149 #define UPIO_PORT               (SERIAL_IO_PORT)        /* 8b I/O port access */
 150 #define UPIO_HUB6               (SERIAL_IO_HUB6)        /* Hub6 ISA card */
 151 #define UPIO_MEM                (SERIAL_IO_MEM)         /* driver-specific */
 152 #define UPIO_MEM32              (SERIAL_IO_MEM32)       /* 32b little endian */
 153 #define UPIO_AU                 (SERIAL_IO_AU)          /* Au1x00 and RT288x type IO */
 154 #define UPIO_TSI                (SERIAL_IO_TSI)         /* Tsi108/109 type IO */
 155 #define UPIO_MEM32BE            (SERIAL_IO_MEM32BE)     /* 32b big endian */
 156 #define UPIO_MEM16              (SERIAL_IO_MEM16)       /* 16b little endian */
 157
 158         /* quirks must be updated while holding port mutex */
 159 #define UPQ_NO_TXEN_TEST        BIT(0)
 160
 161         unsigned int            read_status_mask;       /* driver specific */
 162         unsigned int            ignore_status_mask;     /* driver specific */
 163         struct uart_state       *state;                 /* pointer to parent state */
 164         struct uart_icount      icount;                 /* statistics */
 165
 166         struct console          *cons;                  /* struct console, if any */
 167 #if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(SUPPORT_SYSRQ)
 168         unsigned long           sysrq;                  /* sysrq timeout */
 169         unsigned int            sysrq_ch;               /* char for sysrq */
 170 #endif
 171
 172         /* flags must be updated while holding port mutex */
 173         upf_t                   flags;
 174
 175         /*
 176          * These flags must be equivalent to the flags defined in
 177          * include/uapi/linux/tty_flags.h which are the userspace definitions
 178          * assigned from the serial_struct flags in uart_set_info()
 179          * [for bit definitions in the UPF_CHANGE_MASK]
 180          *
 181          * Bits [0..UPF_LAST_USER] are userspace defined/visible/changeable
 182          * The remaining bits are serial-core specific and not modifiable by
 183          * userspace.
 184          */
 185 #define UPF_FOURPORT            ((__force upf_t) ASYNC_FOURPORT       /* 1  */ )
 186 #define UPF_SAK                 ((__force upf_t) ASYNC_SAK            /* 2  */ )
 187 #define UPF_SPD_HI              ((__force upf_t) ASYNC_SPD_HI         /* 4  */ )
 188 #define UPF_SPD_VHI             ((__force upf_t) ASYNC_SPD_VHI        /* 5  */ )
 189 #define UPF_SPD_CUST            ((__force upf_t) ASYNC_SPD_CUST   /* 0x0030 */ )
 190 #define UPF_SPD_WARP            ((__force upf_t) ASYNC_SPD_WARP   /* 0x1010 */ )
 191 #define UPF_SPD_MASK            ((__force upf_t) ASYNC_SPD_MASK   /* 0x1030 */ )
 192 #define UPF_SKIP_TEST           ((__force upf_t) ASYNC_SKIP_TEST      /* 6  */ )
 193 #define UPF_AUTO_IRQ            ((__force upf_t) ASYNC_AUTO_IRQ       /* 7  */ )
 194 #define UPF_HARDPPS_CD          ((__force upf_t) ASYNC_HARDPPS_CD     /* 11 */ )
 195 #define UPF_SPD_SHI             ((__force upf_t) ASYNC_SPD_SHI        /* 12 */ )
 196 #define UPF_LOW_LATENCY         ((__force upf_t) ASYNC_LOW_LATENCY    /* 13 */ )
 197 #define UPF_BUGGY_UART          ((__force upf_t) ASYNC_BUGGY_UART     /* 14 */ )
 198 #define UPF_MAGIC_MULTIPLIER    ((__force upf_t) ASYNC_MAGIC_MULTIPLIER /* 16 */ )
 199
 200 #define UPF_NO_THRE_TEST        ((__force upf_t) (1 << 19))
 201 /* Port has hardware-assisted h/w flow control */
 202 #define UPF_AUTO_CTS            ((__force upf_t) (1 << 20))
 203 #define UPF_AUTO_RTS            ((__force upf_t) (1 << 21))
 204 #define UPF_HARD_FLOW           ((__force upf_t) (UPF_AUTO_CTS | UPF_AUTO_RTS))
 205 /* Port has hardware-assisted s/w flow control */
 206 #define UPF_SOFT_FLOW           ((__force upf_t) (1 << 22))
 207 #define UPF_CONS_FLOW           ((__force upf_t) (1 << 23))
 208 #define UPF_SHARE_IRQ           ((__force upf_t) (1 << 24))
 209 #define UPF_EXAR_EFR            ((__force upf_t) (1 << 25))
 210 #define UPF_BUG_THRE            ((__force upf_t) (1 << 26))
 211 /* The exact UART type is known and should not be probed.  */
 212 #define UPF_FIXED_TYPE          ((__force upf_t) (1 << 27))
 213 #define UPF_BOOT_AUTOCONF       ((__force upf_t) (1 << 28))
 214 #define UPF_FIXED_PORT          ((__force upf_t) (1 << 29))
 215 #define UPF_DEAD                ((__force upf_t) (1 << 30))
 216 #define UPF_IOREMAP             ((__force upf_t) (1 << 31))
 217
 218 #define __UPF_CHANGE_MASK       0x17fff
 219 #define UPF_CHANGE_MASK         ((__force upf_t) __UPF_CHANGE_MASK)
 220 #define UPF_USR_MASK            ((__force upf_t) (UPF_SPD_MASK|UPF_LOW_LATENCY))
 221
 222 #if __UPF_CHANGE_MASK > ASYNC_FLAGS
 223 #error Change mask not equivalent to userspace-visible bit defines
 224 #endif
 225
 226         /*
 227          * Must hold termios_rwsem, port mutex and port lock to change;
 228          * can hold any one lock to read.
 229          */
 230         upstat_t                status;
 231
 232 #define UPSTAT_CTS_ENABLE       ((__force upstat_t) (1 << 0))
 233 #define UPSTAT_DCD_ENABLE       ((__force upstat_t) (1 << 1))
 234 #define UPSTAT_AUTORTS          ((__force upstat_t) (1 << 2))
 235 #define UPSTAT_AUTOCTS          ((__force upstat_t) (1 << 3))
 236 #define UPSTAT_AUTOXOFF         ((__force upstat_t) (1 << 4))
 237
 238         int                     hw_stopped;             /* sw-assisted CTS flow state */
 239         unsigned int            mctrl;                  /* current modem ctrl settings */
 240         unsigned int            timeout;                /* character-based timeout */
 241         unsigned int            type;                   /* port type */
 242         const struct uart_ops   *ops;
 243         unsigned int            custom_divisor;
 244         unsigned int            line;                   /* port index */
 245         unsigned int            minor;
 246         resource_size_t         mapbase;                /* for ioremap */
 247         resource_size_t         mapsize;
 248         struct device           *dev;                   /* parent device */
 249         unsigned char           hub6;                   /* this should be in the 8250 driver */
 250         unsigned char           suspended;
 251         unsigned char           unused[2];
 252         const char              *name;                  /* port name */
 253         struct attribute_group  *attr_group;            /* port specific attributes */
 254         const struct attribute_group **tty_groups;      /* all attributes (serial core use only) */
 255         struct serial_rs485     rs485;
 256         void                    *private_data;          /* generic platform data pointer */
 257 };
 258
 259 static inline int serial_port_in(struct uart_port *up, int offset)
 260 {
 261         return up->serial_in(up, offset);
 262 }
 263
 264 static inline void serial_port_out(struct uart_port *up, int offset, int value)
 265 {
 266         up->serial_out(up, offset, value);
 267 }
 268
 269 /**
 270  * enum uart_pm_state - power states for UARTs
 271  * @UART_PM_STATE_ON: UART is powered, up and operational
 272  * @UART_PM_STATE_OFF: UART is powered off
 273  * @UART_PM_STATE_UNDEFINED: sentinel
 274  */
 275 enum uart_pm_state {
 276         UART_PM_STATE_ON = 0,
 277         UART_PM_STATE_OFF = 3, /* number taken from ACPI */
 278         UART_PM_STATE_UNDEFINED,
 279 };
 280
 281 /*
 282  * This is the state information which is persistent across opens.
 283  */
 284 struct uart_state {
 285         struct tty_port         port;
 286
 287         enum uart_pm_state      pm_state;
 288         struct circ_buf         xmit;
 289
 290         atomic_t                refcount;
 291         wait_queue_head_t       remove_wait;
 292         struct uart_port        *uart_port;
 293 };
 294
 295 #define UART_XMIT_SIZE  PAGE_SIZE
 296
 297
 298 /* number of characters left in xmit buffer before we ask for more */
 299 #define WAKEUP_CHARS            256
 300
 301 struct module;
 302 struct tty_driver;
 303
 304 struct uart_driver {
 305         struct module           *owner;
 306         const char              *driver_name;
 307         const char              *dev_name;
 308         int                      major;
 309         int                      minor;
 310         int                      nr;
 311         struct console          *cons;
 312
 313         /*
 314          * these are private; the low level driver should not
 315          * touch these; they should be initialised to NULL
 316          */
 317         struct uart_state       *state;
 318         struct tty_driver       *tty_driver;
 319 };
 320
 321 void uart_write_wakeup(struct uart_port *port);
 322
 323 /*
 324  * Baud rate helpers.
 325  */
 326 void uart_update_timeout(struct uart_port *port, unsigned int cflag,
 327                          unsigned int baud);
 328 unsigned int uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
 329                                 struct ktermios *old, unsigned int min,
 330                                 unsigned int max);
 331 unsigned int uart_get_divisor(struct uart_port *port, unsigned int baud);
 332
 333 /* Base timer interval for polling */
 334 static inline int uart_poll_timeout(struct uart_port *port)
 335 {
 336         int timeout = port->timeout;
 337
 338         return timeout > 6 ? (timeout / 2 - 2) : 1;
 339 }
 340
 341 /*
 342  * Console helpers.
 343  */
 344 struct earlycon_device {
 345         struct console *con;
 346         struct uart_port port;
 347         char options[16];               /* e.g., 115200n8 */
 348         unsigned int baud;
 349 };
 350
 351 struct earlycon_id {
 352         char    name[15];
 353         char    name_term;      /* In case compiler didn't '\0' term name */
 354         char    compatible[128];
 355         int     (*setup)(struct earlycon_device *, const char *options);
 356 };
 357
 358 extern const struct earlycon_id *__earlycon_table[];
 359 extern const struct earlycon_id *__earlycon_table_end[];
 360
 361 #if defined(CONFIG_SERIAL_EARLYCON) && !defined(MODULE)
 362 #define EARLYCON_USED_OR_UNUSED __used
 363 #else
 364 #define EARLYCON_USED_OR_UNUSED __maybe_unused
 365 #endif
 366
 367 #define _OF_EARLYCON_DECLARE(_name, compat, fn, unique_id)              \
 368         static const struct earlycon_id unique_id                       \
 369              EARLYCON_USED_OR_UNUSED __initconst                        \
 370                 = { .name = __stringify(_name),                         \
 371                     .compatible = compat,                               \
 372                     .setup = fn  };                                     \
 373         static const struct earlycon_id EARLYCON_USED_OR_UNUSED         \
 374                 __section(__earlycon_table)                             \
 375                 * const __PASTE(__p, unique_id) = &unique_id
 376
 377 #define OF_EARLYCON_DECLARE(_name, compat, fn)                          \
 378         _OF_EARLYCON_DECLARE(_name, compat, fn,                         \
 379                              __UNIQUE_ID(__earlycon_##_name))
 380
 381 #define EARLYCON_DECLARE(_name, fn)     OF_EARLYCON_DECLARE(_name, "", fn)
 382
 383 extern int of_setup_earlycon(const struct earlycon_id *match,
 384                              unsigned long node,
 385                              const char *options);
 386
 387 #ifdef CONFIG_SERIAL_EARLYCON
 388 extern bool earlycon_init_is_deferred __initdata;
 389 int setup_earlycon(char *buf);
 390 #else
 391 static const bool earlycon_init_is_deferred;
 392 static inline int setup_earlycon(char *buf) { return 0; }
 393 #endif
 394
 395 struct uart_port *uart_get_console(struct uart_port *ports, int nr,
 396                                    struct console *c);
 397 int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
 398                         char **options);
 399 void uart_parse_options(char *options, int *baud, int *parity, int *bits,
 400                         int *flow);
 401 int uart_set_options(struct uart_port *port, struct console *co, int baud,
 402                      int parity, int bits, int flow);
 403 struct tty_driver *uart_console_device(struct console *co, int *index);
 404 void uart_console_write(struct uart_port *port, const char *s,
 405                         unsigned int count,
 406                         void (*putchar)(struct uart_port *, int));
 407
 408 /*
 409  * Port/driver registration/removal
 410  */
 411 int uart_register_driver(struct uart_driver *uart);
 412 void uart_unregister_driver(struct uart_driver *uart);
 413 int uart_add_one_port(struct uart_driver *reg, struct uart_port *port);
 414 int uart_remove_one_port(struct uart_driver *reg, struct uart_port *port);
 415 int uart_match_port(struct uart_port *port1, struct uart_port *port2);
 416
 417 /*
 418  * Power Management
 419  */
 420 int uart_suspend_port(struct uart_driver *reg, struct uart_port *port);
 421 int uart_resume_port(struct uart_driver *reg, struct uart_port *port);
 422
 423 #define uart_circ_empty(circ)           ((circ)->head == (circ)->tail)
 424 #define uart_circ_clear(circ)           ((circ)->head = (circ)->tail = 0)
 425
 426 #define uart_circ_chars_pending(circ)   \
 427         (CIRC_CNT((circ)->head, (circ)->tail, UART_XMIT_SIZE))
 428
 429 #define uart_circ_chars_free(circ)      \
 430         (CIRC_SPACE((circ)->head, (circ)->tail, UART_XMIT_SIZE))
 431
 432 static inline int uart_tx_stopped(struct uart_port *port)
 433 {
 434         struct tty_struct *tty = port->state->port.tty;
 435         if ((tty && tty->stopped) || port->hw_stopped)
 436                 return 1;
 437         return 0;
 438 }
 439
 440 static inline bool uart_cts_enabled(struct uart_port *uport)
 441 {
 442         return !!(uport->status & UPSTAT_CTS_ENABLE);
 443 }
 444
 445 static inline bool uart_softcts_mode(struct uart_port *uport)
 446 {
 447         upstat_t mask = UPSTAT_CTS_ENABLE | UPSTAT_AUTOCTS;
 448
 449         return ((uport->status & mask) == UPSTAT_CTS_ENABLE);
 450 }
 451
 452 /*
 453  * The following are helper functions for the low level drivers.
 454  */
 455
 456 extern void uart_handle_dcd_change(struct uart_port *uport,
 457                 unsigned int status);
 458 extern void uart_handle_cts_change(struct uart_port *uport,
 459                 unsigned int status);
 460
 461 extern void uart_insert_char(struct uart_port *port, unsigned int status,
 462                  unsigned int overrun, unsigned int ch, unsigned int flag);
 463
 464 #if defined(SUPPORT_SYSRQ) && defined(CONFIG_MAGIC_SYSRQ_SERIAL)
 465 static inline int
 466 uart_handle_sysrq_char(struct uart_port *port, unsigned int ch)
 467 {
 468         if (port->sysrq) {
 469                 if (ch && time_before(jiffies, port->sysrq)) {
 470                         handle_sysrq(ch);
 471                         port->sysrq = 0;
 472                         return 1;
 473                 }
 474                 port->sysrq = 0;
 475         }
 476         return 0;
 477 }
 478 static inline int
 479 uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch)
 480 {
 481         if (port->sysrq) {
 482                 if (ch && time_before(jiffies, port->sysrq)) {
 483                         port->sysrq_ch = ch;
 484                         port->sysrq = 0;
 485                         return 1;
 486                 }
 487                 port->sysrq = 0;
 488         }
 489         return 0;
 490 }
 491 static inline void
 492 uart_unlock_and_check_sysrq(struct uart_port *port, unsigned long irqflags)
 493 {
 494         int sysrq_ch;
 495
 496         sysrq_ch = port->sysrq_ch;
 497         port->sysrq_ch = 0;
 498
 499         spin_unlock_irqrestore(&port->lock, irqflags);
 500
 501         if (sysrq_ch)
 502                 handle_sysrq(sysrq_ch);
 503 }
 504 #else
 505 static inline int
 506 uart_handle_sysrq_char(struct uart_port *port, unsigned int ch) { return 0; }
 507 static inline int
 508 uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch) { return 0; }
 509 static inline void
 510 uart_unlock_and_check_sysrq(struct uart_port *port, unsigned long irqflags)
 511 {
 512         spin_unlock_irqrestore(&port->lock, irqflags);
 513 }
 514 #endif
 515
 516 /*
 517  * We do the SysRQ and SAK checking like this...
 518  */
 519 static inline int uart_handle_break(struct uart_port *port)
 520 {
 521         struct uart_state *state = port->state;
 522
 523         if (port->handle_break)
 524                 port->handle_break(port);
 525
 526 #ifdef SUPPORT_SYSRQ
 527         if (port->cons && port->cons->index == port->line) {
 528                 if (!port->sysrq) {
 529                         port->sysrq = jiffies + HZ*5;
 530                         return 1;
 531                 }
 532                 port->sysrq = 0;
 533         }
 534 #endif
 535         if (port->flags & UPF_SAK)
 536                 do_SAK(state->port.tty);
 537         return 0;
 538 }
 539
 540 /*
 541  *      UART_ENABLE_MS - determine if port should enable modem status irqs
 542  */
 543 #define UART_ENABLE_MS(port,cflag)      ((port)->flags & UPF_HARDPPS_CD || \
 544                                          (cflag) & CRTSCTS || \
 545                                          !((cflag) & CLOCAL))
 546
 547 /*
 548  * Common device tree parsing helpers
 549  */
 550 void of_get_rs485_mode(struct device_node *np, struct serial_rs485 *rs485conf);
 551
 552 #endif /* LINUX_SERIAL_CORE_H */