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 (*enable_ms)(struct uart_port *); 49 void (*break_ctl)(struct uart_port *, int ctl); 50 int (*startup)(struct uart_port *); 51 void (*shutdown)(struct uart_port *); 52 void (*flush_buffer)(struct uart_port *); 53 void (*set_termios)(struct uart_port *, struct ktermios *new, 54 struct ktermios *old); 55 void (*set_ldisc)(struct uart_port *, struct ktermios *); 56 void (*pm)(struct uart_port *, unsigned int state, 57 unsigned int oldstate); 58 59 /* 60 * Return a string describing the type of the port 61 */ 62 const char *(*type)(struct uart_port *); 63 64 /* 65 * Release IO and memory resources used by the port. 66 * This includes iounmap if necessary. 67 */ 68 void (*release_port)(struct uart_port *); 69 70 /* 71 * Request IO and memory resources used by the port. 72 * This includes iomapping the port if necessary. 73 */ 74 int (*request_port)(struct uart_port *); 75 void (*config_port)(struct uart_port *, int); 76 int (*verify_port)(struct uart_port *, struct serial_struct *); 77 int (*ioctl)(struct uart_port *, unsigned int, unsigned long); 78 #ifdef CONFIG_CONSOLE_POLL 79 int (*poll_init)(struct uart_port *); 80 void (*poll_put_char)(struct uart_port *, unsigned char); 81 int (*poll_get_char)(struct uart_port *); 82 #endif 83 }; 84 85 #define NO_POLL_CHAR 0x00ff0000 86 #define UART_CONFIG_TYPE (1 << 0) 87 #define UART_CONFIG_IRQ (1 << 1) 88 89 struct uart_icount { 90 __u32 cts; 91 __u32 dsr; 92 __u32 rng; 93 __u32 dcd; 94 __u32 rx; 95 __u32 tx; 96 __u32 frame; 97 __u32 overrun; 98 __u32 parity; 99 __u32 brk; 100 __u32 buf_overrun; 101 }; 102 103 typedef unsigned int __bitwise upf_t; 104 typedef unsigned int __bitwise upstat_t; 105 106 struct uart_port { 107 spinlock_t lock; /* port lock */ 108 unsigned long iobase; /* in/out[bwl] */ 109 unsigned char __iomem *membase; /* read/write[bwl] */ 110 unsigned int (*serial_in)(struct uart_port *, int); 111 void (*serial_out)(struct uart_port *, int, int); 112 void (*set_termios)(struct uart_port *, 113 struct ktermios *new, 114 struct ktermios *old); 115 void (*set_ldisc)(struct uart_port *, 116 struct ktermios *); 117 unsigned int (*get_mctrl)(struct uart_port *); 118 void (*set_mctrl)(struct uart_port *, unsigned int); 119 unsigned int (*get_divisor)(struct uart_port *, 120 unsigned int baud, 121 unsigned int *frac); 122 void (*set_divisor)(struct uart_port *, 123 unsigned int baud, 124 unsigned int quot, 125 unsigned int quot_frac); 126 int (*startup)(struct uart_port *port); 127 void (*shutdown)(struct uart_port *port); 128 void (*throttle)(struct uart_port *port); 129 void (*unthrottle)(struct uart_port *port); 130 int (*handle_irq)(struct uart_port *); 131 void (*pm)(struct uart_port *, unsigned int state, 132 unsigned int old); 133 void (*handle_break)(struct uart_port *); 134 int (*rs485_config)(struct uart_port *, 135 struct serial_rs485 *rs485); 136 int (*iso7816_config)(struct uart_port *, 137 struct serial_iso7816 *iso7816); 138 unsigned int irq; /* irq number */ 139 unsigned long irqflags; /* irq flags */ 140 unsigned int uartclk; /* base uart clock */ 141 unsigned int fifosize; /* tx fifo size */ 142 unsigned char x_char; /* xon/xoff char */ 143 unsigned char regshift; /* reg offset shift */ 144 unsigned char iotype; /* io access style */ 145 unsigned char quirks; /* internal quirks */ 146 147 #define UPIO_PORT (SERIAL_IO_PORT) /* 8b I/O port access */ 148 #define UPIO_HUB6 (SERIAL_IO_HUB6) /* Hub6 ISA card */ 149 #define UPIO_MEM (SERIAL_IO_MEM) /* driver-specific */ 150 #define UPIO_MEM32 (SERIAL_IO_MEM32) /* 32b little endian */ 151 #define UPIO_AU (SERIAL_IO_AU) /* Au1x00 and RT288x type IO */ 152 #define UPIO_TSI (SERIAL_IO_TSI) /* Tsi108/109 type IO */ 153 #define UPIO_MEM32BE (SERIAL_IO_MEM32BE) /* 32b big endian */ 154 #define UPIO_MEM16 (SERIAL_IO_MEM16) /* 16b little endian */ 155 156 /* quirks must be updated while holding port mutex */ 157 #define UPQ_NO_TXEN_TEST BIT(0) 158 159 unsigned int read_status_mask; /* driver specific */ 160 unsigned int ignore_status_mask; /* driver specific */ 161 struct uart_state *state; /* pointer to parent state */ 162 struct uart_icount icount; /* statistics */ 163 164 struct console *cons; /* struct console, if any */ 165 /* flags must be updated while holding port mutex */ 166 upf_t flags; 167 168 /* 169 * These flags must be equivalent to the flags defined in 170 * include/uapi/linux/tty_flags.h which are the userspace definitions 171 * assigned from the serial_struct flags in uart_set_info() 172 * [for bit definitions in the UPF_CHANGE_MASK] 173 * 174 * Bits [0..ASYNCB_LAST_USER] are userspace defined/visible/changeable 175 * The remaining bits are serial-core specific and not modifiable by 176 * userspace. 177 */ 178 #define UPF_FOURPORT ((__force upf_t) ASYNC_FOURPORT /* 1 */ ) 179 #define UPF_SAK ((__force upf_t) ASYNC_SAK /* 2 */ ) 180 #define UPF_SPD_HI ((__force upf_t) ASYNC_SPD_HI /* 4 */ ) 181 #define UPF_SPD_VHI ((__force upf_t) ASYNC_SPD_VHI /* 5 */ ) 182 #define UPF_SPD_CUST ((__force upf_t) ASYNC_SPD_CUST /* 0x0030 */ ) 183 #define UPF_SPD_WARP ((__force upf_t) ASYNC_SPD_WARP /* 0x1010 */ ) 184 #define UPF_SPD_MASK ((__force upf_t) ASYNC_SPD_MASK /* 0x1030 */ ) 185 #define UPF_SKIP_TEST ((__force upf_t) ASYNC_SKIP_TEST /* 6 */ ) 186 #define UPF_AUTO_IRQ ((__force upf_t) ASYNC_AUTO_IRQ /* 7 */ ) 187 #define UPF_HARDPPS_CD ((__force upf_t) ASYNC_HARDPPS_CD /* 11 */ ) 188 #define UPF_SPD_SHI ((__force upf_t) ASYNC_SPD_SHI /* 12 */ ) 189 #define UPF_LOW_LATENCY ((__force upf_t) ASYNC_LOW_LATENCY /* 13 */ ) 190 #define UPF_BUGGY_UART ((__force upf_t) ASYNC_BUGGY_UART /* 14 */ ) 191 #define UPF_MAGIC_MULTIPLIER ((__force upf_t) ASYNC_MAGIC_MULTIPLIER /* 16 */ ) 192 193 #define UPF_NO_THRE_TEST ((__force upf_t) (1 << 19)) 194 /* Port has hardware-assisted h/w flow control */ 195 #define UPF_AUTO_CTS ((__force upf_t) (1 << 20)) 196 #define UPF_AUTO_RTS ((__force upf_t) (1 << 21)) 197 #define UPF_HARD_FLOW ((__force upf_t) (UPF_AUTO_CTS | UPF_AUTO_RTS)) 198 /* Port has hardware-assisted s/w flow control */ 199 #define UPF_SOFT_FLOW ((__force upf_t) (1 << 22)) 200 #define UPF_CONS_FLOW ((__force upf_t) (1 << 23)) 201 #define UPF_SHARE_IRQ ((__force upf_t) (1 << 24)) 202 #define UPF_EXAR_EFR ((__force upf_t) (1 << 25)) 203 #define UPF_BUG_THRE ((__force upf_t) (1 << 26)) 204 /* The exact UART type is known and should not be probed. */ 205 #define UPF_FIXED_TYPE ((__force upf_t) (1 << 27)) 206 #define UPF_BOOT_AUTOCONF ((__force upf_t) (1 << 28)) 207 #define UPF_FIXED_PORT ((__force upf_t) (1 << 29)) 208 #define UPF_DEAD ((__force upf_t) (1 << 30)) 209 #define UPF_IOREMAP ((__force upf_t) (1 << 31)) 210 211 #define __UPF_CHANGE_MASK 0x17fff 212 #define UPF_CHANGE_MASK ((__force upf_t) __UPF_CHANGE_MASK) 213 #define UPF_USR_MASK ((__force upf_t) (UPF_SPD_MASK|UPF_LOW_LATENCY)) 214 215 #if __UPF_CHANGE_MASK > ASYNC_FLAGS 216 #error Change mask not equivalent to userspace-visible bit defines 217 #endif 218 219 /* 220 * Must hold termios_rwsem, port mutex and port lock to change; 221 * can hold any one lock to read. 222 */ 223 upstat_t status; 224 225 #define UPSTAT_CTS_ENABLE ((__force upstat_t) (1 << 0)) 226 #define UPSTAT_DCD_ENABLE ((__force upstat_t) (1 << 1)) 227 #define UPSTAT_AUTORTS ((__force upstat_t) (1 << 2)) 228 #define UPSTAT_AUTOCTS ((__force upstat_t) (1 << 3)) 229 #define UPSTAT_AUTOXOFF ((__force upstat_t) (1 << 4)) 230 #define UPSTAT_SYNC_FIFO ((__force upstat_t) (1 << 5)) 231 232 int hw_stopped; /* sw-assisted CTS flow state */ 233 unsigned int mctrl; /* current modem ctrl settings */ 234 unsigned int timeout; /* character-based timeout */ 235 unsigned int type; /* port type */ 236 const struct uart_ops *ops; 237 unsigned int custom_divisor; 238 unsigned int line; /* port index */ 239 unsigned int minor; 240 resource_size_t mapbase; /* for ioremap */ 241 resource_size_t mapsize; 242 struct device *dev; /* parent device */ 243 244 unsigned long sysrq; /* sysrq timeout */ 245 unsigned int sysrq_ch; /* char for sysrq */ 246 unsigned char has_sysrq; 247 unsigned char sysrq_seq; /* index in sysrq_toggle_seq */ 248 249 unsigned char hub6; /* this should be in the 8250 driver */ 250 unsigned char suspended; 251 unsigned char console_reinit; 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 struct gpio_desc *rs485_term_gpio; /* enable RS485 bus termination */ 257 struct serial_iso7816 iso7816; 258 void *private_data; /* generic platform data pointer */ 259 }; 260 261 static inline int serial_port_in(struct uart_port *up, int offset) 262 { 263 return up->serial_in(up, offset); 264 } 265 266 static inline void serial_port_out(struct uart_port *up, int offset, int value) 267 { 268 up->serial_out(up, offset, value); 269 } 270 271 /** 272 * enum uart_pm_state - power states for UARTs 273 * @UART_PM_STATE_ON: UART is powered, up and operational 274 * @UART_PM_STATE_OFF: UART is powered off 275 * @UART_PM_STATE_UNDEFINED: sentinel 276 */ 277 enum uart_pm_state { 278 UART_PM_STATE_ON = 0, 279 UART_PM_STATE_OFF = 3, /* number taken from ACPI */ 280 UART_PM_STATE_UNDEFINED, 281 }; 282 283 /* 284 * This is the state information which is persistent across opens. 285 */ 286 struct uart_state { 287 struct tty_port port; 288 289 enum uart_pm_state pm_state; 290 struct circ_buf xmit; 291 292 atomic_t refcount; 293 wait_queue_head_t remove_wait; 294 struct uart_port *uart_port; 295 }; 296 297 #define UART_XMIT_SIZE PAGE_SIZE 298 299 300 /* number of characters left in xmit buffer before we ask for more */ 301 #define WAKEUP_CHARS 256 302 303 struct module; 304 struct tty_driver; 305 306 struct uart_driver { 307 struct module *owner; 308 const char *driver_name; 309 const char *dev_name; 310 int major; 311 int minor; 312 int nr; 313 struct console *cons; 314 315 /* 316 * these are private; the low level driver should not 317 * touch these; they should be initialised to NULL 318 */ 319 struct uart_state *state; 320 struct tty_driver *tty_driver; 321 }; 322 323 void uart_write_wakeup(struct uart_port *port); 324 325 /* 326 * Baud rate helpers. 327 */ 328 void uart_update_timeout(struct uart_port *port, unsigned int cflag, 329 unsigned int baud); 330 unsigned int uart_get_baud_rate(struct uart_port *port, struct ktermios *termios, 331 struct ktermios *old, unsigned int min, 332 unsigned int max); 333 unsigned int uart_get_divisor(struct uart_port *port, unsigned int baud); 334 335 /* Base timer interval for polling */ 336 static inline int uart_poll_timeout(struct uart_port *port) 337 { 338 int timeout = port->timeout; 339 340 return timeout > 6 ? (timeout / 2 - 2) : 1; 341 } 342 343 /* 344 * Console helpers. 345 */ 346 struct earlycon_device { 347 struct console *con; 348 struct uart_port port; 349 char options[16]; /* e.g., 115200n8 */ 350 unsigned int baud; 351 }; 352 353 struct earlycon_id { 354 char name[15]; 355 char name_term; /* In case compiler didn't '\0' term name */ 356 char compatible[128]; 357 int (*setup)(struct earlycon_device *, const char *options); 358 }; 359 360 extern const struct earlycon_id __earlycon_table[]; 361 extern const struct earlycon_id __earlycon_table_end[]; 362 363 #if defined(CONFIG_SERIAL_EARLYCON) && !defined(MODULE) 364 #define EARLYCON_USED_OR_UNUSED __used 365 #else 366 #define EARLYCON_USED_OR_UNUSED __maybe_unused 367 #endif 368 369 #define OF_EARLYCON_DECLARE(_name, compat, fn) \ 370 static const struct earlycon_id __UNIQUE_ID(__earlycon_##_name) \ 371 EARLYCON_USED_OR_UNUSED __section("__earlycon_table") \ 372 __aligned(__alignof__(struct earlycon_id)) \ 373 = { .name = __stringify(_name), \ 374 .compatible = compat, \ 375 .setup = fn } 376 377 #define EARLYCON_DECLARE(_name, fn) OF_EARLYCON_DECLARE(_name, "", fn) 378 379 extern int of_setup_earlycon(const struct earlycon_id *match, 380 unsigned long node, 381 const char *options); 382 383 #ifdef CONFIG_SERIAL_EARLYCON 384 extern bool earlycon_acpi_spcr_enable __initdata; 385 int setup_earlycon(char *buf); 386 #else 387 static const bool earlycon_acpi_spcr_enable EARLYCON_USED_OR_UNUSED; 388 static inline int setup_earlycon(char *buf) { return 0; } 389 #endif 390 391 struct uart_port *uart_get_console(struct uart_port *ports, int nr, 392 struct console *c); 393 int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr, 394 char **options); 395 void uart_parse_options(const char *options, int *baud, int *parity, int *bits, 396 int *flow); 397 int uart_set_options(struct uart_port *port, struct console *co, int baud, 398 int parity, int bits, int flow); 399 struct tty_driver *uart_console_device(struct console *co, int *index); 400 void uart_console_write(struct uart_port *port, const char *s, 401 unsigned int count, 402 void (*putchar)(struct uart_port *, unsigned char)); 403 404 /* 405 * Port/driver registration/removal 406 */ 407 int uart_register_driver(struct uart_driver *uart); 408 void uart_unregister_driver(struct uart_driver *uart); 409 int uart_add_one_port(struct uart_driver *reg, struct uart_port *port); 410 int uart_remove_one_port(struct uart_driver *reg, struct uart_port *port); 411 bool uart_match_port(const struct uart_port *port1, 412 const struct uart_port *port2); 413 414 /* 415 * Power Management 416 */ 417 int uart_suspend_port(struct uart_driver *reg, struct uart_port *port); 418 int uart_resume_port(struct uart_driver *reg, struct uart_port *port); 419 420 #define uart_circ_empty(circ) ((circ)->head == (circ)->tail) 421 #define uart_circ_clear(circ) ((circ)->head = (circ)->tail = 0) 422 423 #define uart_circ_chars_pending(circ) \ 424 (CIRC_CNT((circ)->head, (circ)->tail, UART_XMIT_SIZE)) 425 426 #define uart_circ_chars_free(circ) \ 427 (CIRC_SPACE((circ)->head, (circ)->tail, UART_XMIT_SIZE)) 428 429 static inline int uart_tx_stopped(struct uart_port *port) 430 { 431 struct tty_struct *tty = port->state->port.tty; 432 if ((tty && tty->flow.stopped) || port->hw_stopped) 433 return 1; 434 return 0; 435 } 436 437 static inline bool uart_cts_enabled(struct uart_port *uport) 438 { 439 return !!(uport->status & UPSTAT_CTS_ENABLE); 440 } 441 442 static inline bool uart_softcts_mode(struct uart_port *uport) 443 { 444 upstat_t mask = UPSTAT_CTS_ENABLE | UPSTAT_AUTOCTS; 445 446 return ((uport->status & mask) == UPSTAT_CTS_ENABLE); 447 } 448 449 /* 450 * The following are helper functions for the low level drivers. 451 */ 452 453 extern void uart_handle_dcd_change(struct uart_port *uport, 454 unsigned int status); 455 extern void uart_handle_cts_change(struct uart_port *uport, 456 unsigned int status); 457 458 extern void uart_insert_char(struct uart_port *port, unsigned int status, 459 unsigned int overrun, unsigned int ch, unsigned int flag); 460 461 void uart_xchar_out(struct uart_port *uport, int offset); 462 463 #ifdef CONFIG_MAGIC_SYSRQ_SERIAL 464 #define SYSRQ_TIMEOUT (HZ * 5) 465 466 bool uart_try_toggle_sysrq(struct uart_port *port, unsigned int ch); 467 468 static inline int uart_handle_sysrq_char(struct uart_port *port, unsigned int ch) 469 { 470 if (!port->sysrq) 471 return 0; 472 473 if (ch && time_before(jiffies, port->sysrq)) { 474 if (sysrq_mask()) { 475 handle_sysrq(ch); 476 port->sysrq = 0; 477 return 1; 478 } 479 if (uart_try_toggle_sysrq(port, ch)) 480 return 1; 481 } 482 port->sysrq = 0; 483 484 return 0; 485 } 486 487 static inline int uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch) 488 { 489 if (!port->sysrq) 490 return 0; 491 492 if (ch && time_before(jiffies, port->sysrq)) { 493 if (sysrq_mask()) { 494 port->sysrq_ch = ch; 495 port->sysrq = 0; 496 return 1; 497 } 498 if (uart_try_toggle_sysrq(port, ch)) 499 return 1; 500 } 501 port->sysrq = 0; 502 503 return 0; 504 } 505 506 static inline void uart_unlock_and_check_sysrq(struct uart_port *port) 507 { 508 int sysrq_ch; 509 510 if (!port->has_sysrq) { 511 spin_unlock(&port->lock); 512 return; 513 } 514 515 sysrq_ch = port->sysrq_ch; 516 port->sysrq_ch = 0; 517 518 spin_unlock(&port->lock); 519 520 if (sysrq_ch) 521 handle_sysrq(sysrq_ch); 522 } 523 524 static inline void uart_unlock_and_check_sysrq_irqrestore(struct uart_port *port, 525 unsigned long flags) 526 { 527 int sysrq_ch; 528 529 if (!port->has_sysrq) { 530 spin_unlock_irqrestore(&port->lock, flags); 531 return; 532 } 533 534 sysrq_ch = port->sysrq_ch; 535 port->sysrq_ch = 0; 536 537 spin_unlock_irqrestore(&port->lock, flags); 538 539 if (sysrq_ch) 540 handle_sysrq(sysrq_ch); 541 } 542 #else /* CONFIG_MAGIC_SYSRQ_SERIAL */ 543 static inline int uart_handle_sysrq_char(struct uart_port *port, unsigned int ch) 544 { 545 return 0; 546 } 547 static inline int uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch) 548 { 549 return 0; 550 } 551 static inline void uart_unlock_and_check_sysrq(struct uart_port *port) 552 { 553 spin_unlock(&port->lock); 554 } 555 static inline void uart_unlock_and_check_sysrq_irqrestore(struct uart_port *port, 556 unsigned long flags) 557 { 558 spin_unlock_irqrestore(&port->lock, flags); 559 } 560 #endif /* CONFIG_MAGIC_SYSRQ_SERIAL */ 561 562 /* 563 * We do the SysRQ and SAK checking like this... 564 */ 565 static inline int uart_handle_break(struct uart_port *port) 566 { 567 struct uart_state *state = port->state; 568 569 if (port->handle_break) 570 port->handle_break(port); 571 572 #ifdef CONFIG_MAGIC_SYSRQ_SERIAL 573 if (port->has_sysrq && uart_console(port)) { 574 if (!port->sysrq) { 575 port->sysrq = jiffies + SYSRQ_TIMEOUT; 576 return 1; 577 } 578 port->sysrq = 0; 579 } 580 #endif 581 if (port->flags & UPF_SAK) 582 do_SAK(state->port.tty); 583 return 0; 584 } 585 586 /* 587 * UART_ENABLE_MS - determine if port should enable modem status irqs 588 */ 589 #define UART_ENABLE_MS(port,cflag) ((port)->flags & UPF_HARDPPS_CD || \ 590 (cflag) & CRTSCTS || \ 591 !((cflag) & CLOCAL)) 592 593 int uart_get_rs485_mode(struct uart_port *port); 594 #endif /* LINUX_SERIAL_CORE_H */ 595