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