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 frame_time; /* frame timing in ns */ 236 unsigned int type; /* port type */ 237 const struct uart_ops *ops; 238 unsigned int custom_divisor; 239 unsigned int line; /* port index */ 240 unsigned int minor; 241 resource_size_t mapbase; /* for ioremap */ 242 resource_size_t mapsize; 243 struct device *dev; /* parent device */ 244 245 unsigned long sysrq; /* sysrq timeout */ 246 unsigned int sysrq_ch; /* char for sysrq */ 247 unsigned char has_sysrq; 248 unsigned char sysrq_seq; /* index in sysrq_toggle_seq */ 249 250 unsigned char hub6; /* this should be in the 8250 driver */ 251 unsigned char suspended; 252 unsigned char console_reinit; 253 const char *name; /* port name */ 254 struct attribute_group *attr_group; /* port specific attributes */ 255 const struct attribute_group **tty_groups; /* all attributes (serial core use only) */ 256 struct serial_rs485 rs485; 257 struct gpio_desc *rs485_term_gpio; /* enable RS485 bus termination */ 258 struct serial_iso7816 iso7816; 259 void *private_data; /* generic platform data pointer */ 260 }; 261 262 static inline int serial_port_in(struct uart_port *up, int offset) 263 { 264 return up->serial_in(up, offset); 265 } 266 267 static inline void serial_port_out(struct uart_port *up, int offset, int value) 268 { 269 up->serial_out(up, offset, value); 270 } 271 272 /** 273 * enum uart_pm_state - power states for UARTs 274 * @UART_PM_STATE_ON: UART is powered, up and operational 275 * @UART_PM_STATE_OFF: UART is powered off 276 * @UART_PM_STATE_UNDEFINED: sentinel 277 */ 278 enum uart_pm_state { 279 UART_PM_STATE_ON = 0, 280 UART_PM_STATE_OFF = 3, /* number taken from ACPI */ 281 UART_PM_STATE_UNDEFINED, 282 }; 283 284 /* 285 * This is the state information which is persistent across opens. 286 */ 287 struct uart_state { 288 struct tty_port port; 289 290 enum uart_pm_state pm_state; 291 struct circ_buf xmit; 292 293 atomic_t refcount; 294 wait_queue_head_t remove_wait; 295 struct uart_port *uart_port; 296 }; 297 298 #define UART_XMIT_SIZE PAGE_SIZE 299 300 301 /* number of characters left in xmit buffer before we ask for more */ 302 #define WAKEUP_CHARS 256 303 304 struct module; 305 struct tty_driver; 306 307 struct uart_driver { 308 struct module *owner; 309 const char *driver_name; 310 const char *dev_name; 311 int major; 312 int minor; 313 int nr; 314 struct console *cons; 315 316 /* 317 * these are private; the low level driver should not 318 * touch these; they should be initialised to NULL 319 */ 320 struct uart_state *state; 321 struct tty_driver *tty_driver; 322 }; 323 324 void uart_write_wakeup(struct uart_port *port); 325 326 /* 327 * Baud rate helpers. 328 */ 329 void uart_update_timeout(struct uart_port *port, unsigned int cflag, 330 unsigned int baud); 331 unsigned int uart_get_baud_rate(struct uart_port *port, struct ktermios *termios, 332 struct ktermios *old, unsigned int min, 333 unsigned int max); 334 unsigned int uart_get_divisor(struct uart_port *port, unsigned int baud); 335 336 /* Base timer interval for polling */ 337 static inline int uart_poll_timeout(struct uart_port *port) 338 { 339 int timeout = port->timeout; 340 341 return timeout > 6 ? (timeout / 2 - 2) : 1; 342 } 343 344 /* 345 * Console helpers. 346 */ 347 struct earlycon_device { 348 struct console *con; 349 struct uart_port port; 350 char options[16]; /* e.g., 115200n8 */ 351 unsigned int baud; 352 }; 353 354 struct earlycon_id { 355 char name[15]; 356 char name_term; /* In case compiler didn't '\0' term name */ 357 char compatible[128]; 358 int (*setup)(struct earlycon_device *, const char *options); 359 }; 360 361 extern const struct earlycon_id __earlycon_table[]; 362 extern const struct earlycon_id __earlycon_table_end[]; 363 364 #if defined(CONFIG_SERIAL_EARLYCON) && !defined(MODULE) 365 #define EARLYCON_USED_OR_UNUSED __used 366 #else 367 #define EARLYCON_USED_OR_UNUSED __maybe_unused 368 #endif 369 370 #define OF_EARLYCON_DECLARE(_name, compat, fn) \ 371 static const struct earlycon_id __UNIQUE_ID(__earlycon_##_name) \ 372 EARLYCON_USED_OR_UNUSED __section("__earlycon_table") \ 373 __aligned(__alignof__(struct earlycon_id)) \ 374 = { .name = __stringify(_name), \ 375 .compatible = compat, \ 376 .setup = fn } 377 378 #define EARLYCON_DECLARE(_name, fn) OF_EARLYCON_DECLARE(_name, "", fn) 379 380 extern int of_setup_earlycon(const struct earlycon_id *match, 381 unsigned long node, 382 const char *options); 383 384 #ifdef CONFIG_SERIAL_EARLYCON 385 extern bool earlycon_acpi_spcr_enable __initdata; 386 int setup_earlycon(char *buf); 387 #else 388 static const bool earlycon_acpi_spcr_enable EARLYCON_USED_OR_UNUSED; 389 static inline int setup_earlycon(char *buf) { return 0; } 390 #endif 391 392 struct uart_port *uart_get_console(struct uart_port *ports, int nr, 393 struct console *c); 394 int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr, 395 char **options); 396 void uart_parse_options(const char *options, int *baud, int *parity, int *bits, 397 int *flow); 398 int uart_set_options(struct uart_port *port, struct console *co, int baud, 399 int parity, int bits, int flow); 400 struct tty_driver *uart_console_device(struct console *co, int *index); 401 void uart_console_write(struct uart_port *port, const char *s, 402 unsigned int count, 403 void (*putchar)(struct uart_port *, unsigned char)); 404 405 /* 406 * Port/driver registration/removal 407 */ 408 int uart_register_driver(struct uart_driver *uart); 409 void uart_unregister_driver(struct uart_driver *uart); 410 int uart_add_one_port(struct uart_driver *reg, struct uart_port *port); 411 int uart_remove_one_port(struct uart_driver *reg, struct uart_port *port); 412 bool uart_match_port(const struct uart_port *port1, 413 const struct uart_port *port2); 414 415 /* 416 * Power Management 417 */ 418 int uart_suspend_port(struct uart_driver *reg, struct uart_port *port); 419 int uart_resume_port(struct uart_driver *reg, struct uart_port *port); 420 421 #define uart_circ_empty(circ) ((circ)->head == (circ)->tail) 422 #define uart_circ_clear(circ) ((circ)->head = (circ)->tail = 0) 423 424 #define uart_circ_chars_pending(circ) \ 425 (CIRC_CNT((circ)->head, (circ)->tail, UART_XMIT_SIZE)) 426 427 #define uart_circ_chars_free(circ) \ 428 (CIRC_SPACE((circ)->head, (circ)->tail, UART_XMIT_SIZE)) 429 430 static inline int uart_tx_stopped(struct uart_port *port) 431 { 432 struct tty_struct *tty = port->state->port.tty; 433 if ((tty && tty->flow.stopped) || port->hw_stopped) 434 return 1; 435 return 0; 436 } 437 438 static inline bool uart_cts_enabled(struct uart_port *uport) 439 { 440 return !!(uport->status & UPSTAT_CTS_ENABLE); 441 } 442 443 static inline bool uart_softcts_mode(struct uart_port *uport) 444 { 445 upstat_t mask = UPSTAT_CTS_ENABLE | UPSTAT_AUTOCTS; 446 447 return ((uport->status & mask) == UPSTAT_CTS_ENABLE); 448 } 449 450 /* 451 * The following are helper functions for the low level drivers. 452 */ 453 454 extern void uart_handle_dcd_change(struct uart_port *uport, 455 unsigned int status); 456 extern void uart_handle_cts_change(struct uart_port *uport, 457 unsigned int status); 458 459 extern void uart_insert_char(struct uart_port *port, unsigned int status, 460 unsigned int overrun, unsigned int ch, unsigned int flag); 461 462 void uart_xchar_out(struct uart_port *uport, int offset); 463 464 #ifdef CONFIG_MAGIC_SYSRQ_SERIAL 465 #define SYSRQ_TIMEOUT (HZ * 5) 466 467 bool uart_try_toggle_sysrq(struct uart_port *port, unsigned int ch); 468 469 static inline int uart_handle_sysrq_char(struct uart_port *port, unsigned int ch) 470 { 471 if (!port->sysrq) 472 return 0; 473 474 if (ch && time_before(jiffies, port->sysrq)) { 475 if (sysrq_mask()) { 476 handle_sysrq(ch); 477 port->sysrq = 0; 478 return 1; 479 } 480 if (uart_try_toggle_sysrq(port, ch)) 481 return 1; 482 } 483 port->sysrq = 0; 484 485 return 0; 486 } 487 488 static inline int uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch) 489 { 490 if (!port->sysrq) 491 return 0; 492 493 if (ch && time_before(jiffies, port->sysrq)) { 494 if (sysrq_mask()) { 495 port->sysrq_ch = ch; 496 port->sysrq = 0; 497 return 1; 498 } 499 if (uart_try_toggle_sysrq(port, ch)) 500 return 1; 501 } 502 port->sysrq = 0; 503 504 return 0; 505 } 506 507 static inline void uart_unlock_and_check_sysrq(struct uart_port *port) 508 { 509 int sysrq_ch; 510 511 if (!port->has_sysrq) { 512 spin_unlock(&port->lock); 513 return; 514 } 515 516 sysrq_ch = port->sysrq_ch; 517 port->sysrq_ch = 0; 518 519 spin_unlock(&port->lock); 520 521 if (sysrq_ch) 522 handle_sysrq(sysrq_ch); 523 } 524 525 static inline void uart_unlock_and_check_sysrq_irqrestore(struct uart_port *port, 526 unsigned long flags) 527 { 528 int sysrq_ch; 529 530 if (!port->has_sysrq) { 531 spin_unlock_irqrestore(&port->lock, flags); 532 return; 533 } 534 535 sysrq_ch = port->sysrq_ch; 536 port->sysrq_ch = 0; 537 538 spin_unlock_irqrestore(&port->lock, flags); 539 540 if (sysrq_ch) 541 handle_sysrq(sysrq_ch); 542 } 543 #else /* CONFIG_MAGIC_SYSRQ_SERIAL */ 544 static inline int uart_handle_sysrq_char(struct uart_port *port, unsigned int ch) 545 { 546 return 0; 547 } 548 static inline int uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch) 549 { 550 return 0; 551 } 552 static inline void uart_unlock_and_check_sysrq(struct uart_port *port) 553 { 554 spin_unlock(&port->lock); 555 } 556 static inline void uart_unlock_and_check_sysrq_irqrestore(struct uart_port *port, 557 unsigned long flags) 558 { 559 spin_unlock_irqrestore(&port->lock, flags); 560 } 561 #endif /* CONFIG_MAGIC_SYSRQ_SERIAL */ 562 563 /* 564 * We do the SysRQ and SAK checking like this... 565 */ 566 static inline int uart_handle_break(struct uart_port *port) 567 { 568 struct uart_state *state = port->state; 569 570 if (port->handle_break) 571 port->handle_break(port); 572 573 #ifdef CONFIG_MAGIC_SYSRQ_SERIAL 574 if (port->has_sysrq && uart_console(port)) { 575 if (!port->sysrq) { 576 port->sysrq = jiffies + SYSRQ_TIMEOUT; 577 return 1; 578 } 579 port->sysrq = 0; 580 } 581 #endif 582 if (port->flags & UPF_SAK) 583 do_SAK(state->port.tty); 584 return 0; 585 } 586 587 /* 588 * UART_ENABLE_MS - determine if port should enable modem status irqs 589 */ 590 #define UART_ENABLE_MS(port,cflag) ((port)->flags & UPF_HARDPPS_CD || \ 591 (cflag) & CRTSCTS || \ 592 !((cflag) & CLOCAL)) 593 594 int uart_get_rs485_mode(struct uart_port *port); 595 #endif /* LINUX_SERIAL_CORE_H */ 596