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 serial_rs485 *rs485); 137 int (*iso7816_config)(struct uart_port *, 138 struct serial_iso7816 *iso7816); 139 unsigned int irq; /* irq number */ 140 unsigned long irqflags; /* irq flags */ 141 unsigned int uartclk; /* base uart clock */ 142 unsigned int fifosize; /* tx fifo size */ 143 unsigned char x_char; /* xon/xoff char */ 144 unsigned char regshift; /* reg offset shift */ 145 unsigned char iotype; /* io access style */ 146 unsigned char quirks; /* internal quirks */ 147 148 #define UPIO_PORT (SERIAL_IO_PORT) /* 8b I/O port access */ 149 #define UPIO_HUB6 (SERIAL_IO_HUB6) /* Hub6 ISA card */ 150 #define UPIO_MEM (SERIAL_IO_MEM) /* driver-specific */ 151 #define UPIO_MEM32 (SERIAL_IO_MEM32) /* 32b little endian */ 152 #define UPIO_AU (SERIAL_IO_AU) /* Au1x00 and RT288x type IO */ 153 #define UPIO_TSI (SERIAL_IO_TSI) /* Tsi108/109 type IO */ 154 #define UPIO_MEM32BE (SERIAL_IO_MEM32BE) /* 32b big endian */ 155 #define UPIO_MEM16 (SERIAL_IO_MEM16) /* 16b little endian */ 156 157 /* quirks must be updated while holding port mutex */ 158 #define UPQ_NO_TXEN_TEST BIT(0) 159 160 unsigned int read_status_mask; /* driver specific */ 161 unsigned int ignore_status_mask; /* driver specific */ 162 struct uart_state *state; /* pointer to parent state */ 163 struct uart_icount icount; /* statistics */ 164 165 struct console *cons; /* struct console, if any */ 166 /* flags must be updated while holding port mutex */ 167 upf_t flags; 168 169 /* 170 * These flags must be equivalent to the flags defined in 171 * include/uapi/linux/tty_flags.h which are the userspace definitions 172 * assigned from the serial_struct flags in uart_set_info() 173 * [for bit definitions in the UPF_CHANGE_MASK] 174 * 175 * Bits [0..ASYNCB_LAST_USER] are userspace defined/visible/changeable 176 * The remaining bits are serial-core specific and not modifiable by 177 * userspace. 178 */ 179 #define UPF_FOURPORT ((__force upf_t) ASYNC_FOURPORT /* 1 */ ) 180 #define UPF_SAK ((__force upf_t) ASYNC_SAK /* 2 */ ) 181 #define UPF_SPD_HI ((__force upf_t) ASYNC_SPD_HI /* 4 */ ) 182 #define UPF_SPD_VHI ((__force upf_t) ASYNC_SPD_VHI /* 5 */ ) 183 #define UPF_SPD_CUST ((__force upf_t) ASYNC_SPD_CUST /* 0x0030 */ ) 184 #define UPF_SPD_WARP ((__force upf_t) ASYNC_SPD_WARP /* 0x1010 */ ) 185 #define UPF_SPD_MASK ((__force upf_t) ASYNC_SPD_MASK /* 0x1030 */ ) 186 #define UPF_SKIP_TEST ((__force upf_t) ASYNC_SKIP_TEST /* 6 */ ) 187 #define UPF_AUTO_IRQ ((__force upf_t) ASYNC_AUTO_IRQ /* 7 */ ) 188 #define UPF_HARDPPS_CD ((__force upf_t) ASYNC_HARDPPS_CD /* 11 */ ) 189 #define UPF_SPD_SHI ((__force upf_t) ASYNC_SPD_SHI /* 12 */ ) 190 #define UPF_LOW_LATENCY ((__force upf_t) ASYNC_LOW_LATENCY /* 13 */ ) 191 #define UPF_BUGGY_UART ((__force upf_t) ASYNC_BUGGY_UART /* 14 */ ) 192 #define UPF_MAGIC_MULTIPLIER ((__force upf_t) ASYNC_MAGIC_MULTIPLIER /* 16 */ ) 193 194 #define UPF_NO_THRE_TEST ((__force upf_t) (1 << 19)) 195 /* Port has hardware-assisted h/w flow control */ 196 #define UPF_AUTO_CTS ((__force upf_t) (1 << 20)) 197 #define UPF_AUTO_RTS ((__force upf_t) (1 << 21)) 198 #define UPF_HARD_FLOW ((__force upf_t) (UPF_AUTO_CTS | UPF_AUTO_RTS)) 199 /* Port has hardware-assisted s/w flow control */ 200 #define UPF_SOFT_FLOW ((__force upf_t) (1 << 22)) 201 #define UPF_CONS_FLOW ((__force upf_t) (1 << 23)) 202 #define UPF_SHARE_IRQ ((__force upf_t) (1 << 24)) 203 #define UPF_EXAR_EFR ((__force upf_t) (1 << 25)) 204 #define UPF_BUG_THRE ((__force upf_t) (1 << 26)) 205 /* The exact UART type is known and should not be probed. */ 206 #define UPF_FIXED_TYPE ((__force upf_t) (1 << 27)) 207 #define UPF_BOOT_AUTOCONF ((__force upf_t) (1 << 28)) 208 #define UPF_FIXED_PORT ((__force upf_t) (1 << 29)) 209 #define UPF_DEAD ((__force upf_t) (1 << 30)) 210 #define UPF_IOREMAP ((__force upf_t) (1 << 31)) 211 212 #define __UPF_CHANGE_MASK 0x17fff 213 #define UPF_CHANGE_MASK ((__force upf_t) __UPF_CHANGE_MASK) 214 #define UPF_USR_MASK ((__force upf_t) (UPF_SPD_MASK|UPF_LOW_LATENCY)) 215 216 #if __UPF_CHANGE_MASK > ASYNC_FLAGS 217 #error Change mask not equivalent to userspace-visible bit defines 218 #endif 219 220 /* 221 * Must hold termios_rwsem, port mutex and port lock to change; 222 * can hold any one lock to read. 223 */ 224 upstat_t status; 225 226 #define UPSTAT_CTS_ENABLE ((__force upstat_t) (1 << 0)) 227 #define UPSTAT_DCD_ENABLE ((__force upstat_t) (1 << 1)) 228 #define UPSTAT_AUTORTS ((__force upstat_t) (1 << 2)) 229 #define UPSTAT_AUTOCTS ((__force upstat_t) (1 << 3)) 230 #define UPSTAT_AUTOXOFF ((__force upstat_t) (1 << 4)) 231 #define UPSTAT_SYNC_FIFO ((__force upstat_t) (1 << 5)) 232 233 int hw_stopped; /* sw-assisted CTS flow state */ 234 unsigned int mctrl; /* current modem ctrl settings */ 235 unsigned int timeout; /* character-based timeout */ 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 struct gpio_desc *rs485_term_gpio; /* enable RS485 bus termination */ 259 struct serial_iso7816 iso7816; 260 void *private_data; /* generic platform data pointer */ 261 }; 262 263 static inline int serial_port_in(struct uart_port *up, int offset) 264 { 265 return up->serial_in(up, offset); 266 } 267 268 static inline void serial_port_out(struct uart_port *up, int offset, int value) 269 { 270 up->serial_out(up, offset, value); 271 } 272 273 /** 274 * enum uart_pm_state - power states for UARTs 275 * @UART_PM_STATE_ON: UART is powered, up and operational 276 * @UART_PM_STATE_OFF: UART is powered off 277 * @UART_PM_STATE_UNDEFINED: sentinel 278 */ 279 enum uart_pm_state { 280 UART_PM_STATE_ON = 0, 281 UART_PM_STATE_OFF = 3, /* number taken from ACPI */ 282 UART_PM_STATE_UNDEFINED, 283 }; 284 285 /* 286 * This is the state information which is persistent across opens. 287 */ 288 struct uart_state { 289 struct tty_port port; 290 291 enum uart_pm_state pm_state; 292 struct circ_buf xmit; 293 294 atomic_t refcount; 295 wait_queue_head_t remove_wait; 296 struct uart_port *uart_port; 297 }; 298 299 #define UART_XMIT_SIZE PAGE_SIZE 300 301 302 /* number of characters left in xmit buffer before we ask for more */ 303 #define WAKEUP_CHARS 256 304 305 struct module; 306 struct tty_driver; 307 308 struct uart_driver { 309 struct module *owner; 310 const char *driver_name; 311 const char *dev_name; 312 int major; 313 int minor; 314 int nr; 315 struct console *cons; 316 317 /* 318 * these are private; the low level driver should not 319 * touch these; they should be initialised to NULL 320 */ 321 struct uart_state *state; 322 struct tty_driver *tty_driver; 323 }; 324 325 void uart_write_wakeup(struct uart_port *port); 326 327 /* 328 * Baud rate helpers. 329 */ 330 void uart_update_timeout(struct uart_port *port, unsigned int cflag, 331 unsigned int baud); 332 unsigned int uart_get_baud_rate(struct uart_port *port, struct ktermios *termios, 333 struct ktermios *old, unsigned int min, 334 unsigned int max); 335 unsigned int uart_get_divisor(struct uart_port *port, unsigned int baud); 336 337 /* Base timer interval for polling */ 338 static inline int uart_poll_timeout(struct uart_port *port) 339 { 340 int timeout = port->timeout; 341 342 return timeout > 6 ? (timeout / 2 - 2) : 1; 343 } 344 345 /* 346 * Console helpers. 347 */ 348 struct earlycon_device { 349 struct console *con; 350 struct uart_port port; 351 char options[16]; /* e.g., 115200n8 */ 352 unsigned int baud; 353 }; 354 355 struct earlycon_id { 356 char name[15]; 357 char name_term; /* In case compiler didn't '\0' term name */ 358 char compatible[128]; 359 int (*setup)(struct earlycon_device *, const char *options); 360 }; 361 362 extern const struct earlycon_id __earlycon_table[]; 363 extern const struct earlycon_id __earlycon_table_end[]; 364 365 #if defined(CONFIG_SERIAL_EARLYCON) && !defined(MODULE) 366 #define EARLYCON_USED_OR_UNUSED __used 367 #else 368 #define EARLYCON_USED_OR_UNUSED __maybe_unused 369 #endif 370 371 #define OF_EARLYCON_DECLARE(_name, compat, fn) \ 372 static const struct earlycon_id __UNIQUE_ID(__earlycon_##_name) \ 373 EARLYCON_USED_OR_UNUSED __section("__earlycon_table") \ 374 __aligned(__alignof__(struct earlycon_id)) \ 375 = { .name = __stringify(_name), \ 376 .compatible = compat, \ 377 .setup = fn } 378 379 #define EARLYCON_DECLARE(_name, fn) OF_EARLYCON_DECLARE(_name, "", fn) 380 381 extern int of_setup_earlycon(const struct earlycon_id *match, 382 unsigned long node, 383 const char *options); 384 385 #ifdef CONFIG_SERIAL_EARLYCON 386 extern bool earlycon_acpi_spcr_enable __initdata; 387 int setup_earlycon(char *buf); 388 #else 389 static const bool earlycon_acpi_spcr_enable EARLYCON_USED_OR_UNUSED; 390 static inline int setup_earlycon(char *buf) { return 0; } 391 #endif 392 393 struct uart_port *uart_get_console(struct uart_port *ports, int nr, 394 struct console *c); 395 int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr, 396 char **options); 397 void uart_parse_options(const char *options, int *baud, int *parity, int *bits, 398 int *flow); 399 int uart_set_options(struct uart_port *port, struct console *co, int baud, 400 int parity, int bits, int flow); 401 struct tty_driver *uart_console_device(struct console *co, int *index); 402 void uart_console_write(struct uart_port *port, const char *s, 403 unsigned int count, 404 void (*putchar)(struct uart_port *, unsigned char)); 405 406 /* 407 * Port/driver registration/removal 408 */ 409 int uart_register_driver(struct uart_driver *uart); 410 void uart_unregister_driver(struct uart_driver *uart); 411 int uart_add_one_port(struct uart_driver *reg, struct uart_port *port); 412 int uart_remove_one_port(struct uart_driver *reg, struct uart_port *port); 413 bool uart_match_port(const struct uart_port *port1, 414 const struct uart_port *port2); 415 416 /* 417 * Power Management 418 */ 419 int uart_suspend_port(struct uart_driver *reg, struct uart_port *port); 420 int uart_resume_port(struct uart_driver *reg, struct uart_port *port); 421 422 #define uart_circ_empty(circ) ((circ)->head == (circ)->tail) 423 #define uart_circ_clear(circ) ((circ)->head = (circ)->tail = 0) 424 425 #define uart_circ_chars_pending(circ) \ 426 (CIRC_CNT((circ)->head, (circ)->tail, UART_XMIT_SIZE)) 427 428 #define uart_circ_chars_free(circ) \ 429 (CIRC_SPACE((circ)->head, (circ)->tail, UART_XMIT_SIZE)) 430 431 static inline int uart_tx_stopped(struct uart_port *port) 432 { 433 struct tty_struct *tty = port->state->port.tty; 434 if ((tty && tty->flow.stopped) || port->hw_stopped) 435 return 1; 436 return 0; 437 } 438 439 static inline bool uart_cts_enabled(struct uart_port *uport) 440 { 441 return !!(uport->status & UPSTAT_CTS_ENABLE); 442 } 443 444 static inline bool uart_softcts_mode(struct uart_port *uport) 445 { 446 upstat_t mask = UPSTAT_CTS_ENABLE | UPSTAT_AUTOCTS; 447 448 return ((uport->status & mask) == UPSTAT_CTS_ENABLE); 449 } 450 451 /* 452 * The following are helper functions for the low level drivers. 453 */ 454 455 extern void uart_handle_dcd_change(struct uart_port *uport, 456 unsigned int status); 457 extern void uart_handle_cts_change(struct uart_port *uport, 458 unsigned int status); 459 460 extern void uart_insert_char(struct uart_port *port, unsigned int status, 461 unsigned int overrun, unsigned int ch, unsigned int flag); 462 463 void uart_xchar_out(struct uart_port *uport, int offset); 464 465 #ifdef CONFIG_MAGIC_SYSRQ_SERIAL 466 #define SYSRQ_TIMEOUT (HZ * 5) 467 468 bool uart_try_toggle_sysrq(struct uart_port *port, unsigned int ch); 469 470 static inline int uart_handle_sysrq_char(struct uart_port *port, unsigned int ch) 471 { 472 if (!port->sysrq) 473 return 0; 474 475 if (ch && time_before(jiffies, port->sysrq)) { 476 if (sysrq_mask()) { 477 handle_sysrq(ch); 478 port->sysrq = 0; 479 return 1; 480 } 481 if (uart_try_toggle_sysrq(port, ch)) 482 return 1; 483 } 484 port->sysrq = 0; 485 486 return 0; 487 } 488 489 static inline int uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch) 490 { 491 if (!port->sysrq) 492 return 0; 493 494 if (ch && time_before(jiffies, port->sysrq)) { 495 if (sysrq_mask()) { 496 port->sysrq_ch = ch; 497 port->sysrq = 0; 498 return 1; 499 } 500 if (uart_try_toggle_sysrq(port, ch)) 501 return 1; 502 } 503 port->sysrq = 0; 504 505 return 0; 506 } 507 508 static inline void uart_unlock_and_check_sysrq(struct uart_port *port) 509 { 510 int sysrq_ch; 511 512 if (!port->has_sysrq) { 513 spin_unlock(&port->lock); 514 return; 515 } 516 517 sysrq_ch = port->sysrq_ch; 518 port->sysrq_ch = 0; 519 520 spin_unlock(&port->lock); 521 522 if (sysrq_ch) 523 handle_sysrq(sysrq_ch); 524 } 525 526 static inline void uart_unlock_and_check_sysrq_irqrestore(struct uart_port *port, 527 unsigned long flags) 528 { 529 int sysrq_ch; 530 531 if (!port->has_sysrq) { 532 spin_unlock_irqrestore(&port->lock, flags); 533 return; 534 } 535 536 sysrq_ch = port->sysrq_ch; 537 port->sysrq_ch = 0; 538 539 spin_unlock_irqrestore(&port->lock, flags); 540 541 if (sysrq_ch) 542 handle_sysrq(sysrq_ch); 543 } 544 #else /* CONFIG_MAGIC_SYSRQ_SERIAL */ 545 static inline int uart_handle_sysrq_char(struct uart_port *port, unsigned int ch) 546 { 547 return 0; 548 } 549 static inline int uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch) 550 { 551 return 0; 552 } 553 static inline void uart_unlock_and_check_sysrq(struct uart_port *port) 554 { 555 spin_unlock(&port->lock); 556 } 557 static inline void uart_unlock_and_check_sysrq_irqrestore(struct uart_port *port, 558 unsigned long flags) 559 { 560 spin_unlock_irqrestore(&port->lock, flags); 561 } 562 #endif /* CONFIG_MAGIC_SYSRQ_SERIAL */ 563 564 /* 565 * We do the SysRQ and SAK checking like this... 566 */ 567 static inline int uart_handle_break(struct uart_port *port) 568 { 569 struct uart_state *state = port->state; 570 571 if (port->handle_break) 572 port->handle_break(port); 573 574 #ifdef CONFIG_MAGIC_SYSRQ_SERIAL 575 if (port->has_sysrq && uart_console(port)) { 576 if (!port->sysrq) { 577 port->sysrq = jiffies + SYSRQ_TIMEOUT; 578 return 1; 579 } 580 port->sysrq = 0; 581 } 582 #endif 583 if (port->flags & UPF_SAK) 584 do_SAK(state->port.tty); 585 return 0; 586 } 587 588 /* 589 * UART_ENABLE_MS - determine if port should enable modem status irqs 590 */ 591 #define UART_ENABLE_MS(port,cflag) ((port)->flags & UPF_HARDPPS_CD || \ 592 (cflag) & CRTSCTS || \ 593 !((cflag) & CLOCAL)) 594 595 int uart_get_rs485_mode(struct uart_port *port); 596 #endif /* LINUX_SERIAL_CORE_H */ 597