1 /* SPDX-License-Identifier: GPL-2.0-or-later */ 2 /* 3 * linux/drivers/char/serial_core.h 4 * 5 * Copyright (C) 2000 Deep Blue Solutions Ltd. 6 */ 7 #ifndef LINUX_SERIAL_CORE_H 8 #define LINUX_SERIAL_CORE_H 9 10 #include <linux/bitops.h> 11 #include <linux/compiler.h> 12 #include <linux/console.h> 13 #include <linux/interrupt.h> 14 #include <linux/circ_buf.h> 15 #include <linux/spinlock.h> 16 #include <linux/sched.h> 17 #include <linux/tty.h> 18 #include <linux/mutex.h> 19 #include <linux/sysrq.h> 20 #include <uapi/linux/serial_core.h> 21 22 #ifdef CONFIG_SERIAL_CORE_CONSOLE 23 #define uart_console(port) \ 24 ((port)->cons && (port)->cons->index == (port)->line) 25 #else 26 #define uart_console(port) ({ (void)port; 0; }) 27 #endif 28 29 struct uart_port; 30 struct serial_struct; 31 struct device; 32 struct gpio_desc; 33 34 /* 35 * This structure describes all the operations that can be done on the 36 * physical hardware. See Documentation/driver-api/serial/driver.rst for details. 37 */ 38 struct uart_ops { 39 unsigned int (*tx_empty)(struct uart_port *); 40 void (*set_mctrl)(struct uart_port *, unsigned int mctrl); 41 unsigned int (*get_mctrl)(struct uart_port *); 42 void (*stop_tx)(struct uart_port *); 43 void (*start_tx)(struct uart_port *); 44 void (*throttle)(struct uart_port *); 45 void (*unthrottle)(struct uart_port *); 46 void (*send_xchar)(struct uart_port *, char ch); 47 void (*stop_rx)(struct uart_port *); 48 void (*start_rx)(struct uart_port *); 49 void (*enable_ms)(struct uart_port *); 50 void (*break_ctl)(struct uart_port *, int ctl); 51 int (*startup)(struct uart_port *); 52 void (*shutdown)(struct uart_port *); 53 void (*flush_buffer)(struct uart_port *); 54 void (*set_termios)(struct uart_port *, struct ktermios *new, 55 struct ktermios *old); 56 void (*set_ldisc)(struct uart_port *, struct ktermios *); 57 void (*pm)(struct uart_port *, unsigned int state, 58 unsigned int oldstate); 59 60 /* 61 * Return a string describing the type of the port 62 */ 63 const char *(*type)(struct uart_port *); 64 65 /* 66 * Release IO and memory resources used by the port. 67 * This includes iounmap if necessary. 68 */ 69 void (*release_port)(struct uart_port *); 70 71 /* 72 * Request IO and memory resources used by the port. 73 * This includes iomapping the port if necessary. 74 */ 75 int (*request_port)(struct uart_port *); 76 void (*config_port)(struct uart_port *, int); 77 int (*verify_port)(struct uart_port *, struct serial_struct *); 78 int (*ioctl)(struct uart_port *, unsigned int, unsigned long); 79 #ifdef CONFIG_CONSOLE_POLL 80 int (*poll_init)(struct uart_port *); 81 void (*poll_put_char)(struct uart_port *, unsigned char); 82 int (*poll_get_char)(struct uart_port *); 83 #endif 84 }; 85 86 #define NO_POLL_CHAR 0x00ff0000 87 #define UART_CONFIG_TYPE (1 << 0) 88 #define UART_CONFIG_IRQ (1 << 1) 89 90 struct uart_icount { 91 __u32 cts; 92 __u32 dsr; 93 __u32 rng; 94 __u32 dcd; 95 __u32 rx; 96 __u32 tx; 97 __u32 frame; 98 __u32 overrun; 99 __u32 parity; 100 __u32 brk; 101 __u32 buf_overrun; 102 }; 103 104 typedef unsigned int __bitwise upf_t; 105 typedef unsigned int __bitwise upstat_t; 106 107 struct uart_port { 108 spinlock_t lock; /* port lock */ 109 unsigned long iobase; /* in/out[bwl] */ 110 unsigned char __iomem *membase; /* read/write[bwl] */ 111 unsigned int (*serial_in)(struct uart_port *, int); 112 void (*serial_out)(struct uart_port *, int, int); 113 void (*set_termios)(struct uart_port *, 114 struct ktermios *new, 115 struct ktermios *old); 116 void (*set_ldisc)(struct uart_port *, 117 struct ktermios *); 118 unsigned int (*get_mctrl)(struct uart_port *); 119 void (*set_mctrl)(struct uart_port *, unsigned int); 120 unsigned int (*get_divisor)(struct uart_port *, 121 unsigned int baud, 122 unsigned int *frac); 123 void (*set_divisor)(struct uart_port *, 124 unsigned int baud, 125 unsigned int quot, 126 unsigned int quot_frac); 127 int (*startup)(struct uart_port *port); 128 void (*shutdown)(struct uart_port *port); 129 void (*throttle)(struct uart_port *port); 130 void (*unthrottle)(struct uart_port *port); 131 int (*handle_irq)(struct uart_port *); 132 void (*pm)(struct uart_port *, unsigned int state, 133 unsigned int old); 134 void (*handle_break)(struct uart_port *); 135 int (*rs485_config)(struct uart_port *, 136 struct ktermios *termios, 137 struct serial_rs485 *rs485); 138 int (*iso7816_config)(struct uart_port *, 139 struct serial_iso7816 *iso7816); 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 /* flags must be updated while holding port mutex */ 168 upf_t flags; 169 170 /* 171 * These flags must be equivalent to the flags defined in 172 * include/uapi/linux/tty_flags.h which are the userspace definitions 173 * assigned from the serial_struct flags in uart_set_info() 174 * [for bit definitions in the UPF_CHANGE_MASK] 175 * 176 * Bits [0..ASYNCB_LAST_USER] are userspace defined/visible/changeable 177 * The remaining bits are serial-core specific and not modifiable by 178 * userspace. 179 */ 180 #define UPF_FOURPORT ((__force upf_t) ASYNC_FOURPORT /* 1 */ ) 181 #define UPF_SAK ((__force upf_t) ASYNC_SAK /* 2 */ ) 182 #define UPF_SPD_HI ((__force upf_t) ASYNC_SPD_HI /* 4 */ ) 183 #define UPF_SPD_VHI ((__force upf_t) ASYNC_SPD_VHI /* 5 */ ) 184 #define UPF_SPD_CUST ((__force upf_t) ASYNC_SPD_CUST /* 0x0030 */ ) 185 #define UPF_SPD_WARP ((__force upf_t) ASYNC_SPD_WARP /* 0x1010 */ ) 186 #define UPF_SPD_MASK ((__force upf_t) ASYNC_SPD_MASK /* 0x1030 */ ) 187 #define UPF_SKIP_TEST ((__force upf_t) ASYNC_SKIP_TEST /* 6 */ ) 188 #define UPF_AUTO_IRQ ((__force upf_t) ASYNC_AUTO_IRQ /* 7 */ ) 189 #define UPF_HARDPPS_CD ((__force upf_t) ASYNC_HARDPPS_CD /* 11 */ ) 190 #define UPF_SPD_SHI ((__force upf_t) ASYNC_SPD_SHI /* 12 */ ) 191 #define UPF_LOW_LATENCY ((__force upf_t) ASYNC_LOW_LATENCY /* 13 */ ) 192 #define UPF_BUGGY_UART ((__force upf_t) ASYNC_BUGGY_UART /* 14 */ ) 193 #define UPF_MAGIC_MULTIPLIER ((__force upf_t) ASYNC_MAGIC_MULTIPLIER /* 16 */ ) 194 195 #define UPF_NO_THRE_TEST ((__force upf_t) (1 << 19)) 196 /* Port has hardware-assisted h/w flow control */ 197 #define UPF_AUTO_CTS ((__force upf_t) (1 << 20)) 198 #define UPF_AUTO_RTS ((__force upf_t) (1 << 21)) 199 #define UPF_HARD_FLOW ((__force upf_t) (UPF_AUTO_CTS | UPF_AUTO_RTS)) 200 /* Port has hardware-assisted s/w flow control */ 201 #define UPF_SOFT_FLOW ((__force upf_t) (1 << 22)) 202 #define UPF_CONS_FLOW ((__force upf_t) (1 << 23)) 203 #define UPF_SHARE_IRQ ((__force upf_t) (1 << 24)) 204 #define UPF_EXAR_EFR ((__force upf_t) (1 << 25)) 205 #define UPF_BUG_THRE ((__force upf_t) (1 << 26)) 206 /* The exact UART type is known and should not be probed. */ 207 #define UPF_FIXED_TYPE ((__force upf_t) (1 << 27)) 208 #define UPF_BOOT_AUTOCONF ((__force upf_t) (1 << 28)) 209 #define UPF_FIXED_PORT ((__force upf_t) (1 << 29)) 210 #define UPF_DEAD ((__force upf_t) (1 << 30)) 211 #define UPF_IOREMAP ((__force upf_t) (1 << 31)) 212 213 #define __UPF_CHANGE_MASK 0x17fff 214 #define UPF_CHANGE_MASK ((__force upf_t) __UPF_CHANGE_MASK) 215 #define UPF_USR_MASK ((__force upf_t) (UPF_SPD_MASK|UPF_LOW_LATENCY)) 216 217 #if __UPF_CHANGE_MASK > ASYNC_FLAGS 218 #error Change mask not equivalent to userspace-visible bit defines 219 #endif 220 221 /* 222 * Must hold termios_rwsem, port mutex and port lock to change; 223 * can hold any one lock to read. 224 */ 225 upstat_t status; 226 227 #define UPSTAT_CTS_ENABLE ((__force upstat_t) (1 << 0)) 228 #define UPSTAT_DCD_ENABLE ((__force upstat_t) (1 << 1)) 229 #define UPSTAT_AUTORTS ((__force upstat_t) (1 << 2)) 230 #define UPSTAT_AUTOCTS ((__force upstat_t) (1 << 3)) 231 #define UPSTAT_AUTOXOFF ((__force upstat_t) (1 << 4)) 232 #define UPSTAT_SYNC_FIFO ((__force upstat_t) (1 << 5)) 233 234 int hw_stopped; /* sw-assisted CTS flow state */ 235 unsigned int mctrl; /* current modem ctrl settings */ 236 unsigned int frame_time; /* frame timing in ns */ 237 unsigned int type; /* port type */ 238 const struct uart_ops *ops; 239 unsigned int custom_divisor; 240 unsigned int line; /* port index */ 241 unsigned int minor; 242 resource_size_t mapbase; /* for ioremap */ 243 resource_size_t mapsize; 244 struct device *dev; /* parent device */ 245 246 unsigned long sysrq; /* sysrq timeout */ 247 unsigned int sysrq_ch; /* char for sysrq */ 248 unsigned char has_sysrq; 249 unsigned char sysrq_seq; /* index in sysrq_toggle_seq */ 250 251 unsigned char hub6; /* this should be in the 8250 driver */ 252 unsigned char suspended; 253 unsigned char console_reinit; 254 const char *name; /* port name */ 255 struct attribute_group *attr_group; /* port specific attributes */ 256 const struct attribute_group **tty_groups; /* all attributes (serial core use only) */ 257 struct serial_rs485 rs485; 258 const struct serial_rs485 *rs485_supported; /* Supported mask for serial_rs485 */ 259 struct gpio_desc *rs485_term_gpio; /* enable RS485 bus termination */ 260 struct serial_iso7816 iso7816; 261 void *private_data; /* generic platform data pointer */ 262 }; 263 264 static inline int serial_port_in(struct uart_port *up, int offset) 265 { 266 return up->serial_in(up, offset); 267 } 268 269 static inline void serial_port_out(struct uart_port *up, int offset, int value) 270 { 271 up->serial_out(up, offset, value); 272 } 273 274 /** 275 * enum uart_pm_state - power states for UARTs 276 * @UART_PM_STATE_ON: UART is powered, up and operational 277 * @UART_PM_STATE_OFF: UART is powered off 278 * @UART_PM_STATE_UNDEFINED: sentinel 279 */ 280 enum uart_pm_state { 281 UART_PM_STATE_ON = 0, 282 UART_PM_STATE_OFF = 3, /* number taken from ACPI */ 283 UART_PM_STATE_UNDEFINED, 284 }; 285 286 /* 287 * This is the state information which is persistent across opens. 288 */ 289 struct uart_state { 290 struct tty_port port; 291 292 enum uart_pm_state pm_state; 293 struct circ_buf xmit; 294 295 atomic_t refcount; 296 wait_queue_head_t remove_wait; 297 struct uart_port *uart_port; 298 }; 299 300 #define UART_XMIT_SIZE PAGE_SIZE 301 302 303 /* number of characters left in xmit buffer before we ask for more */ 304 #define WAKEUP_CHARS 256 305 306 struct module; 307 struct tty_driver; 308 309 struct uart_driver { 310 struct module *owner; 311 const char *driver_name; 312 const char *dev_name; 313 int major; 314 int minor; 315 int nr; 316 struct console *cons; 317 318 /* 319 * these are private; the low level driver should not 320 * touch these; they should be initialised to NULL 321 */ 322 struct uart_state *state; 323 struct tty_driver *tty_driver; 324 }; 325 326 void uart_write_wakeup(struct uart_port *port); 327 328 /* 329 * Baud rate helpers. 330 */ 331 void uart_update_timeout(struct uart_port *port, unsigned int cflag, 332 unsigned int baud); 333 unsigned int uart_get_baud_rate(struct uart_port *port, struct ktermios *termios, 334 struct ktermios *old, unsigned int min, 335 unsigned int max); 336 unsigned int uart_get_divisor(struct uart_port *port, unsigned int baud); 337 338 /* 339 * Calculates FIFO drain time. 340 */ 341 static inline unsigned long uart_fifo_timeout(struct uart_port *port) 342 { 343 u64 fifo_timeout = (u64)READ_ONCE(port->frame_time) * port->fifosize; 344 345 /* Add .02 seconds of slop */ 346 fifo_timeout += 20 * NSEC_PER_MSEC; 347 348 return max(nsecs_to_jiffies(fifo_timeout), 1UL); 349 } 350 351 /* Base timer interval for polling */ 352 static inline int uart_poll_timeout(struct uart_port *port) 353 { 354 int timeout = uart_fifo_timeout(port); 355 356 return timeout > 6 ? (timeout / 2 - 2) : 1; 357 } 358 359 /* 360 * Console helpers. 361 */ 362 struct earlycon_device { 363 struct console *con; 364 struct uart_port port; 365 char options[16]; /* e.g., 115200n8 */ 366 unsigned int baud; 367 }; 368 369 struct earlycon_id { 370 char name[15]; 371 char name_term; /* In case compiler didn't '\0' term name */ 372 char compatible[128]; 373 int (*setup)(struct earlycon_device *, const char *options); 374 }; 375 376 extern const struct earlycon_id __earlycon_table[]; 377 extern const struct earlycon_id __earlycon_table_end[]; 378 379 #if defined(CONFIG_SERIAL_EARLYCON) && !defined(MODULE) 380 #define EARLYCON_USED_OR_UNUSED __used 381 #else 382 #define EARLYCON_USED_OR_UNUSED __maybe_unused 383 #endif 384 385 #define OF_EARLYCON_DECLARE(_name, compat, fn) \ 386 static const struct earlycon_id __UNIQUE_ID(__earlycon_##_name) \ 387 EARLYCON_USED_OR_UNUSED __section("__earlycon_table") \ 388 __aligned(__alignof__(struct earlycon_id)) \ 389 = { .name = __stringify(_name), \ 390 .compatible = compat, \ 391 .setup = fn } 392 393 #define EARLYCON_DECLARE(_name, fn) OF_EARLYCON_DECLARE(_name, "", fn) 394 395 extern int of_setup_earlycon(const struct earlycon_id *match, 396 unsigned long node, 397 const char *options); 398 399 #ifdef CONFIG_SERIAL_EARLYCON 400 extern bool earlycon_acpi_spcr_enable __initdata; 401 int setup_earlycon(char *buf); 402 #else 403 static const bool earlycon_acpi_spcr_enable EARLYCON_USED_OR_UNUSED; 404 static inline int setup_earlycon(char *buf) { return 0; } 405 #endif 406 407 struct uart_port *uart_get_console(struct uart_port *ports, int nr, 408 struct console *c); 409 int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr, 410 char **options); 411 void uart_parse_options(const char *options, int *baud, int *parity, int *bits, 412 int *flow); 413 int uart_set_options(struct uart_port *port, struct console *co, int baud, 414 int parity, int bits, int flow); 415 struct tty_driver *uart_console_device(struct console *co, int *index); 416 void uart_console_write(struct uart_port *port, const char *s, 417 unsigned int count, 418 void (*putchar)(struct uart_port *, unsigned char)); 419 420 /* 421 * Port/driver registration/removal 422 */ 423 int uart_register_driver(struct uart_driver *uart); 424 void uart_unregister_driver(struct uart_driver *uart); 425 int uart_add_one_port(struct uart_driver *reg, struct uart_port *port); 426 int uart_remove_one_port(struct uart_driver *reg, struct uart_port *port); 427 bool uart_match_port(const struct uart_port *port1, 428 const struct uart_port *port2); 429 430 /* 431 * Power Management 432 */ 433 int uart_suspend_port(struct uart_driver *reg, struct uart_port *port); 434 int uart_resume_port(struct uart_driver *reg, struct uart_port *port); 435 436 #define uart_circ_empty(circ) ((circ)->head == (circ)->tail) 437 #define uart_circ_clear(circ) ((circ)->head = (circ)->tail = 0) 438 439 #define uart_circ_chars_pending(circ) \ 440 (CIRC_CNT((circ)->head, (circ)->tail, UART_XMIT_SIZE)) 441 442 #define uart_circ_chars_free(circ) \ 443 (CIRC_SPACE((circ)->head, (circ)->tail, UART_XMIT_SIZE)) 444 445 static inline int uart_tx_stopped(struct uart_port *port) 446 { 447 struct tty_struct *tty = port->state->port.tty; 448 if ((tty && tty->flow.stopped) || port->hw_stopped) 449 return 1; 450 return 0; 451 } 452 453 static inline bool uart_cts_enabled(struct uart_port *uport) 454 { 455 return !!(uport->status & UPSTAT_CTS_ENABLE); 456 } 457 458 static inline bool uart_softcts_mode(struct uart_port *uport) 459 { 460 upstat_t mask = UPSTAT_CTS_ENABLE | UPSTAT_AUTOCTS; 461 462 return ((uport->status & mask) == UPSTAT_CTS_ENABLE); 463 } 464 465 /* 466 * The following are helper functions for the low level drivers. 467 */ 468 469 extern void uart_handle_dcd_change(struct uart_port *uport, 470 unsigned int status); 471 extern void uart_handle_cts_change(struct uart_port *uport, 472 unsigned int status); 473 474 extern void uart_insert_char(struct uart_port *port, unsigned int status, 475 unsigned int overrun, unsigned int ch, unsigned int flag); 476 477 void uart_xchar_out(struct uart_port *uport, int offset); 478 479 #ifdef CONFIG_MAGIC_SYSRQ_SERIAL 480 #define SYSRQ_TIMEOUT (HZ * 5) 481 482 bool uart_try_toggle_sysrq(struct uart_port *port, unsigned int ch); 483 484 static inline int uart_handle_sysrq_char(struct uart_port *port, unsigned int ch) 485 { 486 if (!port->sysrq) 487 return 0; 488 489 if (ch && time_before(jiffies, port->sysrq)) { 490 if (sysrq_mask()) { 491 handle_sysrq(ch); 492 port->sysrq = 0; 493 return 1; 494 } 495 if (uart_try_toggle_sysrq(port, ch)) 496 return 1; 497 } 498 port->sysrq = 0; 499 500 return 0; 501 } 502 503 static inline int uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch) 504 { 505 if (!port->sysrq) 506 return 0; 507 508 if (ch && time_before(jiffies, port->sysrq)) { 509 if (sysrq_mask()) { 510 port->sysrq_ch = ch; 511 port->sysrq = 0; 512 return 1; 513 } 514 if (uart_try_toggle_sysrq(port, ch)) 515 return 1; 516 } 517 port->sysrq = 0; 518 519 return 0; 520 } 521 522 static inline void uart_unlock_and_check_sysrq(struct uart_port *port) 523 { 524 int sysrq_ch; 525 526 if (!port->has_sysrq) { 527 spin_unlock(&port->lock); 528 return; 529 } 530 531 sysrq_ch = port->sysrq_ch; 532 port->sysrq_ch = 0; 533 534 spin_unlock(&port->lock); 535 536 if (sysrq_ch) 537 handle_sysrq(sysrq_ch); 538 } 539 540 static inline void uart_unlock_and_check_sysrq_irqrestore(struct uart_port *port, 541 unsigned long flags) 542 { 543 int sysrq_ch; 544 545 if (!port->has_sysrq) { 546 spin_unlock_irqrestore(&port->lock, flags); 547 return; 548 } 549 550 sysrq_ch = port->sysrq_ch; 551 port->sysrq_ch = 0; 552 553 spin_unlock_irqrestore(&port->lock, flags); 554 555 if (sysrq_ch) 556 handle_sysrq(sysrq_ch); 557 } 558 #else /* CONFIG_MAGIC_SYSRQ_SERIAL */ 559 static inline int uart_handle_sysrq_char(struct uart_port *port, unsigned int ch) 560 { 561 return 0; 562 } 563 static inline int uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch) 564 { 565 return 0; 566 } 567 static inline void uart_unlock_and_check_sysrq(struct uart_port *port) 568 { 569 spin_unlock(&port->lock); 570 } 571 static inline void uart_unlock_and_check_sysrq_irqrestore(struct uart_port *port, 572 unsigned long flags) 573 { 574 spin_unlock_irqrestore(&port->lock, flags); 575 } 576 #endif /* CONFIG_MAGIC_SYSRQ_SERIAL */ 577 578 /* 579 * We do the SysRQ and SAK checking like this... 580 */ 581 static inline int uart_handle_break(struct uart_port *port) 582 { 583 struct uart_state *state = port->state; 584 585 if (port->handle_break) 586 port->handle_break(port); 587 588 #ifdef CONFIG_MAGIC_SYSRQ_SERIAL 589 if (port->has_sysrq && uart_console(port)) { 590 if (!port->sysrq) { 591 port->sysrq = jiffies + SYSRQ_TIMEOUT; 592 return 1; 593 } 594 port->sysrq = 0; 595 } 596 #endif 597 if (port->flags & UPF_SAK) 598 do_SAK(state->port.tty); 599 return 0; 600 } 601 602 /* 603 * UART_ENABLE_MS - determine if port should enable modem status irqs 604 */ 605 #define UART_ENABLE_MS(port,cflag) ((port)->flags & UPF_HARDPPS_CD || \ 606 (cflag) & CRTSCTS || \ 607 !((cflag) & CLOCAL)) 608 609 int uart_get_rs485_mode(struct uart_port *port); 610 int uart_rs485_config(struct uart_port *port); 611 #endif /* LINUX_SERIAL_CORE_H */ 612