include/linux/serial_core.h

   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
  33 /*
  34  * This structure describes all the operations that can be done on the
  35  * physical hardware.  See Documentation/serial/driver.rst for details.
  36  */
  37 struct uart_ops {
  38         unsigned int    (*tx_empty)(struct uart_port *);
  39         void            (*set_mctrl)(struct uart_port *, unsigned int mctrl);
  40         unsigned int    (*get_mctrl)(struct uart_port *);
  41         void            (*stop_tx)(struct uart_port *);
  42         void            (*start_tx)(struct uart_port *);
  43         void            (*throttle)(struct uart_port *);
  44         void            (*unthrottle)(struct uart_port *);
  45         void            (*send_xchar)(struct uart_port *, char ch);
  46         void            (*stop_rx)(struct uart_port *);
  47         void            (*enable_ms)(struct uart_port *);
  48         void            (*break_ctl)(struct uart_port *, int ctl);
  49         int             (*startup)(struct uart_port *);
  50         void            (*shutdown)(struct uart_port *);
  51         void            (*flush_buffer)(struct uart_port *);
  52         void            (*set_termios)(struct uart_port *, struct ktermios *new,
  53                                        struct ktermios *old);
  54         void            (*set_ldisc)(struct uart_port *, struct ktermios *);
  55         void            (*pm)(struct uart_port *, unsigned int state,
  56                               unsigned int oldstate);
  57
  58         /*
  59          * Return a string describing the type of the port
  60          */
  61         const char      *(*type)(struct uart_port *);
  62
  63         /*
  64          * Release IO and memory resources used by the port.
  65          * This includes iounmap if necessary.
  66          */
  67         void            (*release_port)(struct uart_port *);
  68
  69         /*
  70          * Request IO and memory resources used by the port.
  71          * This includes iomapping the port if necessary.
  72          */
  73         int             (*request_port)(struct uart_port *);
  74         void            (*config_port)(struct uart_port *, int);
  75         int             (*verify_port)(struct uart_port *, struct serial_struct *);
  76         int             (*ioctl)(struct uart_port *, unsigned int, unsigned long);
  77 #ifdef CONFIG_CONSOLE_POLL
  78         int             (*poll_init)(struct uart_port *);
  79         void            (*poll_put_char)(struct uart_port *, unsigned char);
  80         int             (*poll_get_char)(struct uart_port *);
  81 #endif
  82 };
  83
  84 #define NO_POLL_CHAR            0x00ff0000
  85 #define UART_CONFIG_TYPE        (1 << 0)
  86 #define UART_CONFIG_IRQ         (1 << 1)
  87
  88 struct uart_icount {
  89         __u32   cts;
  90         __u32   dsr;
  91         __u32   rng;
  92         __u32   dcd;
  93         __u32   rx;
  94         __u32   tx;
  95         __u32   frame;
  96         __u32   overrun;
  97         __u32   parity;
  98         __u32   brk;
  99         __u32   buf_overrun;
 100 };
 101
 102 typedef unsigned int __bitwise upf_t;
 103 typedef unsigned int __bitwise upstat_t;
 104
 105 struct uart_port {
 106         spinlock_t              lock;                   /* port lock */
 107         unsigned long           iobase;                 /* in/out[bwl] */
 108         unsigned char __iomem   *membase;               /* read/write[bwl] */
 109         unsigned int            (*serial_in)(struct uart_port *, int);
 110         void                    (*serial_out)(struct uart_port *, int, int);
 111         void                    (*set_termios)(struct uart_port *,
 112                                                struct ktermios *new,
 113                                                struct ktermios *old);
 114         void                    (*set_ldisc)(struct uart_port *,
 115                                              struct ktermios *);
 116         unsigned int            (*get_mctrl)(struct uart_port *);
 117         void                    (*set_mctrl)(struct uart_port *, unsigned int);
 118         unsigned int            (*get_divisor)(struct uart_port *,
 119                                                unsigned int baud,
 120                                                unsigned int *frac);
 121         void                    (*set_divisor)(struct uart_port *,
 122                                                unsigned int baud,
 123                                                unsigned int quot,
 124                                                unsigned int quot_frac);
 125         int                     (*startup)(struct uart_port *port);
 126         void                    (*shutdown)(struct uart_port *port);
 127         void                    (*throttle)(struct uart_port *port);
 128         void                    (*unthrottle)(struct uart_port *port);
 129         int                     (*handle_irq)(struct uart_port *);
 130         void                    (*pm)(struct uart_port *, unsigned int state,
 131                                       unsigned int old);
 132         void                    (*handle_break)(struct uart_port *);
 133         int                     (*rs485_config)(struct uart_port *,
 134                                                 struct serial_rs485 *rs485);
 135         int                     (*iso7816_config)(struct uart_port *,
 136                                                   struct serial_iso7816 *iso7816);
 137         unsigned int            irq;                    /* irq number */
 138         unsigned long           irqflags;               /* irq flags  */
 139         unsigned int            uartclk;                /* base uart clock */
 140         unsigned int            fifosize;               /* tx fifo size */
 141         unsigned char           x_char;                 /* xon/xoff char */
 142         unsigned char           regshift;               /* reg offset shift */
 143         unsigned char           iotype;                 /* io access style */
 144         unsigned char           quirks;                 /* internal quirks */
 145
 146 #define UPIO_PORT               (SERIAL_IO_PORT)        /* 8b I/O port access */
 147 #define UPIO_HUB6               (SERIAL_IO_HUB6)        /* Hub6 ISA card */
 148 #define UPIO_MEM                (SERIAL_IO_MEM)         /* driver-specific */
 149 #define UPIO_MEM32              (SERIAL_IO_MEM32)       /* 32b little endian */
 150 #define UPIO_AU                 (SERIAL_IO_AU)          /* Au1x00 and RT288x type IO */
 151 #define UPIO_TSI                (SERIAL_IO_TSI)         /* Tsi108/109 type IO */
 152 #define UPIO_MEM32BE            (SERIAL_IO_MEM32BE)     /* 32b big endian */
 153 #define UPIO_MEM16              (SERIAL_IO_MEM16)       /* 16b little endian */
 154
 155         /* quirks must be updated while holding port mutex */
 156 #define UPQ_NO_TXEN_TEST        BIT(0)
 157
 158         unsigned int            read_status_mask;       /* driver specific */
 159         unsigned int            ignore_status_mask;     /* driver specific */
 160         struct uart_state       *state;                 /* pointer to parent state */
 161         struct uart_icount      icount;                 /* statistics */
 162
 163         struct console          *cons;                  /* struct console, if any */
 164 #if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(SUPPORT_SYSRQ)
 165         unsigned long           sysrq;                  /* sysrq timeout */
 166         unsigned int            sysrq_ch;               /* char for sysrq */
 167 #endif
 168
 169         /* flags must be updated while holding port mutex */
 170         upf_t                   flags;
 171
 172         /*
 173          * These flags must be equivalent to the flags defined in
 174          * include/uapi/linux/tty_flags.h which are the userspace definitions
 175          * assigned from the serial_struct flags in uart_set_info()
 176          * [for bit definitions in the UPF_CHANGE_MASK]
 177          *
 178          * Bits [0..UPF_LAST_USER] are userspace defined/visible/changeable
 179          * The remaining bits are serial-core specific and not modifiable by
 180          * userspace.
 181          */
 182 #define UPF_FOURPORT            ((__force upf_t) ASYNC_FOURPORT       /* 1  */ )
 183 #define UPF_SAK                 ((__force upf_t) ASYNC_SAK            /* 2  */ )
 184 #define UPF_SPD_HI              ((__force upf_t) ASYNC_SPD_HI         /* 4  */ )
 185 #define UPF_SPD_VHI             ((__force upf_t) ASYNC_SPD_VHI        /* 5  */ )
 186 #define UPF_SPD_CUST            ((__force upf_t) ASYNC_SPD_CUST   /* 0x0030 */ )
 187 #define UPF_SPD_WARP            ((__force upf_t) ASYNC_SPD_WARP   /* 0x1010 */ )
 188 #define UPF_SPD_MASK            ((__force upf_t) ASYNC_SPD_MASK   /* 0x1030 */ )
 189 #define UPF_SKIP_TEST           ((__force upf_t) ASYNC_SKIP_TEST      /* 6  */ )
 190 #define UPF_AUTO_IRQ            ((__force upf_t) ASYNC_AUTO_IRQ       /* 7  */ )
 191 #define UPF_HARDPPS_CD          ((__force upf_t) ASYNC_HARDPPS_CD     /* 11 */ )
 192 #define UPF_SPD_SHI             ((__force upf_t) ASYNC_SPD_SHI        /* 12 */ )
 193 #define UPF_LOW_LATENCY         ((__force upf_t) ASYNC_LOW_LATENCY    /* 13 */ )
 194 #define UPF_BUGGY_UART          ((__force upf_t) ASYNC_BUGGY_UART     /* 14 */ )
 195 #define UPF_MAGIC_MULTIPLIER    ((__force upf_t) ASYNC_MAGIC_MULTIPLIER /* 16 */ )
 196
 197 #define UPF_NO_THRE_TEST        ((__force upf_t) (1 << 19))
 198 /* Port has hardware-assisted h/w flow control */
 199 #define UPF_AUTO_CTS            ((__force upf_t) (1 << 20))
 200 #define UPF_AUTO_RTS            ((__force upf_t) (1 << 21))
 201 #define UPF_HARD_FLOW           ((__force upf_t) (UPF_AUTO_CTS | UPF_AUTO_RTS))
 202 /* Port has hardware-assisted s/w flow control */
 203 #define UPF_SOFT_FLOW           ((__force upf_t) (1 << 22))
 204 #define UPF_CONS_FLOW           ((__force upf_t) (1 << 23))
 205 #define UPF_SHARE_IRQ           ((__force upf_t) (1 << 24))
 206 #define UPF_EXAR_EFR            ((__force upf_t) (1 << 25))
 207 #define UPF_BUG_THRE            ((__force upf_t) (1 << 26))
 208 /* The exact UART type is known and should not be probed.  */
 209 #define UPF_FIXED_TYPE          ((__force upf_t) (1 << 27))
 210 #define UPF_BOOT_AUTOCONF       ((__force upf_t) (1 << 28))
 211 #define UPF_FIXED_PORT          ((__force upf_t) (1 << 29))
 212 #define UPF_DEAD                ((__force upf_t) (1 << 30))
 213 #define UPF_IOREMAP             ((__force upf_t) (1 << 31))
 214
 215 #define __UPF_CHANGE_MASK       0x17fff
 216 #define UPF_CHANGE_MASK         ((__force upf_t) __UPF_CHANGE_MASK)
 217 #define UPF_USR_MASK            ((__force upf_t) (UPF_SPD_MASK|UPF_LOW_LATENCY))
 218
 219 #if __UPF_CHANGE_MASK > ASYNC_FLAGS
 220 #error Change mask not equivalent to userspace-visible bit defines
 221 #endif
 222
 223         /*
 224          * Must hold termios_rwsem, port mutex and port lock to change;
 225          * can hold any one lock to read.
 226          */
 227         upstat_t                status;
 228
 229 #define UPSTAT_CTS_ENABLE       ((__force upstat_t) (1 << 0))
 230 #define UPSTAT_DCD_ENABLE       ((__force upstat_t) (1 << 1))
 231 #define UPSTAT_AUTORTS          ((__force upstat_t) (1 << 2))
 232 #define UPSTAT_AUTOCTS          ((__force upstat_t) (1 << 3))
 233 #define UPSTAT_AUTOXOFF         ((__force upstat_t) (1 << 4))
 234 #define UPSTAT_SYNC_FIFO        ((__force upstat_t) (1 << 5))
 235
 236         int                     hw_stopped;             /* sw-assisted CTS flow state */
 237         unsigned int            mctrl;                  /* current modem ctrl settings */
 238         unsigned int            timeout;                /* character-based timeout */
 239         unsigned int            type;                   /* port type */
 240         const struct uart_ops   *ops;
 241         unsigned int            custom_divisor;
 242         unsigned int            line;                   /* port index */
 243         unsigned int            minor;
 244         resource_size_t         mapbase;                /* for ioremap */
 245         resource_size_t         mapsize;
 246         struct device           *dev;                   /* parent device */
 247         unsigned char           hub6;                   /* this should be in the 8250 driver */
 248         unsigned char           suspended;
 249         unsigned char           unused[2];
 250         const char              *name;                  /* port name */
 251         struct attribute_group  *attr_group;            /* port specific attributes */
 252         const struct attribute_group **tty_groups;      /* all attributes (serial core use only) */
 253         struct serial_rs485     rs485;
 254         struct serial_iso7816   iso7816;
 255         void                    *private_data;          /* generic platform data pointer */
 256 };
 257
 258 static inline int serial_port_in(struct uart_port *up, int offset)
 259 {
 260         return up->serial_in(up, offset);
 261 }
 262
 263 static inline void serial_port_out(struct uart_port *up, int offset, int value)
 264 {
 265         up->serial_out(up, offset, value);
 266 }
 267
 268 /**
 269  * enum uart_pm_state - power states for UARTs
 270  * @UART_PM_STATE_ON: UART is powered, up and operational
 271  * @UART_PM_STATE_OFF: UART is powered off
 272  * @UART_PM_STATE_UNDEFINED: sentinel
 273  */
 274 enum uart_pm_state {
 275         UART_PM_STATE_ON = 0,
 276         UART_PM_STATE_OFF = 3, /* number taken from ACPI */
 277         UART_PM_STATE_UNDEFINED,
 278 };
 279
 280 /*
 281  * This is the state information which is persistent across opens.
 282  */
 283 struct uart_state {
 284         struct tty_port         port;
 285
 286         enum uart_pm_state      pm_state;
 287         struct circ_buf         xmit;
 288
 289         atomic_t                refcount;
 290         wait_queue_head_t       remove_wait;
 291         struct uart_port        *uart_port;
 292 };
 293
 294 #define UART_XMIT_SIZE  PAGE_SIZE
 295
 296
 297 /* number of characters left in xmit buffer before we ask for more */
 298 #define WAKEUP_CHARS            256
 299
 300 struct module;
 301 struct tty_driver;
 302
 303 struct uart_driver {
 304         struct module           *owner;
 305         const char              *driver_name;
 306         const char              *dev_name;
 307         int                      major;
 308         int                      minor;
 309         int                      nr;
 310         struct console          *cons;
 311
 312         /*
 313          * these are private; the low level driver should not
 314          * touch these; they should be initialised to NULL
 315          */
 316         struct uart_state       *state;
 317         struct tty_driver       *tty_driver;
 318 };
 319
 320 void uart_write_wakeup(struct uart_port *port);
 321
 322 /*
 323  * Baud rate helpers.
 324  */
 325 void uart_update_timeout(struct uart_port *port, unsigned int cflag,
 326                          unsigned int baud);
 327 unsigned int uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
 328                                 struct ktermios *old, unsigned int min,
 329                                 unsigned int max);
 330 unsigned int uart_get_divisor(struct uart_port *port, unsigned int baud);
 331
 332 /* Base timer interval for polling */
 333 static inline int uart_poll_timeout(struct uart_port *port)
 334 {
 335         int timeout = port->timeout;
 336
 337         return timeout > 6 ? (timeout / 2 - 2) : 1;
 338 }
 339
 340 /*
 341  * Console helpers.
 342  */
 343 struct earlycon_device {
 344         struct console *con;
 345         struct uart_port port;
 346         char options[16];               /* e.g., 115200n8 */
 347         unsigned int baud;
 348 };
 349
 350 struct earlycon_id {
 351         char    name[15];
 352         char    name_term;      /* In case compiler didn't '\0' term name */
 353         char    compatible[128];
 354         int     (*setup)(struct earlycon_device *, const char *options);
 355 };
 356
 357 extern const struct earlycon_id *__earlycon_table[];
 358 extern const struct earlycon_id *__earlycon_table_end[];
 359
 360 #if defined(CONFIG_SERIAL_EARLYCON) && !defined(MODULE)
 361 #define EARLYCON_USED_OR_UNUSED __used
 362 #else
 363 #define EARLYCON_USED_OR_UNUSED __maybe_unused
 364 #endif
 365
 366 #define _OF_EARLYCON_DECLARE(_name, compat, fn, unique_id)              \
 367         static const struct earlycon_id unique_id                       \
 368              EARLYCON_USED_OR_UNUSED __initconst                        \
 369                 = { .name = __stringify(_name),                         \
 370                     .compatible = compat,                               \
 371                     .setup = fn  };                                     \
 372         static const struct earlycon_id EARLYCON_USED_OR_UNUSED         \
 373                 __section(__earlycon_table)                             \
 374                 * const __PASTE(__p, unique_id) = &unique_id
 375
 376 #define OF_EARLYCON_DECLARE(_name, compat, fn)                          \
 377         _OF_EARLYCON_DECLARE(_name, compat, fn,                         \
 378                              __UNIQUE_ID(__earlycon_##_name))
 379
 380 #define EARLYCON_DECLARE(_name, fn)     OF_EARLYCON_DECLARE(_name, "", fn)
 381
 382 extern int of_setup_earlycon(const struct earlycon_id *match,
 383                              unsigned long node,
 384                              const char *options);
 385
 386 #ifdef CONFIG_SERIAL_EARLYCON
 387 extern bool earlycon_acpi_spcr_enable __initdata;
 388 int setup_earlycon(char *buf);
 389 #else
 390 static const bool earlycon_acpi_spcr_enable EARLYCON_USED_OR_UNUSED;
 391 static inline int setup_earlycon(char *buf) { return 0; }
 392 #endif
 393
 394 struct uart_port *uart_get_console(struct uart_port *ports, int nr,
 395                                    struct console *c);
 396 int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
 397                         char **options);
 398 void uart_parse_options(const char *options, int *baud, int *parity, int *bits,
 399                         int *flow);
 400 int uart_set_options(struct uart_port *port, struct console *co, int baud,
 401                      int parity, int bits, int flow);
 402 struct tty_driver *uart_console_device(struct console *co, int *index);
 403 void uart_console_write(struct uart_port *port, const char *s,
 404                         unsigned int count,
 405                         void (*putchar)(struct uart_port *, int));
 406
 407 /*
 408  * Port/driver registration/removal
 409  */
 410 int uart_register_driver(struct uart_driver *uart);
 411 void uart_unregister_driver(struct uart_driver *uart);
 412 int uart_add_one_port(struct uart_driver *reg, struct uart_port *port);
 413 int uart_remove_one_port(struct uart_driver *reg, struct uart_port *port);
 414 int uart_match_port(struct uart_port *port1, 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->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 #if defined(SUPPORT_SYSRQ) && defined(CONFIG_MAGIC_SYSRQ_SERIAL)
 464 static inline int
 465 uart_handle_sysrq_char(struct uart_port *port, unsigned int ch)
 466 {
 467         if (port->sysrq) {
 468                 if (ch && time_before(jiffies, port->sysrq)) {
 469                         handle_sysrq(ch);
 470                         port->sysrq = 0;
 471                         return 1;
 472                 }
 473                 port->sysrq = 0;
 474         }
 475         return 0;
 476 }
 477 static inline int
 478 uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch)
 479 {
 480         if (port->sysrq) {
 481                 if (ch && time_before(jiffies, port->sysrq)) {
 482                         port->sysrq_ch = ch;
 483                         port->sysrq = 0;
 484                         return 1;
 485                 }
 486                 port->sysrq = 0;
 487         }
 488         return 0;
 489 }
 490 static inline void
 491 uart_unlock_and_check_sysrq(struct uart_port *port, unsigned long irqflags)
 492 {
 493         int sysrq_ch;
 494
 495         sysrq_ch = port->sysrq_ch;
 496         port->sysrq_ch = 0;
 497
 498         spin_unlock_irqrestore(&port->lock, irqflags);
 499
 500         if (sysrq_ch)
 501                 handle_sysrq(sysrq_ch);
 502 }
 503 #else
 504 static inline int
 505 uart_handle_sysrq_char(struct uart_port *port, unsigned int ch) { return 0; }
 506 static inline int
 507 uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch) { return 0; }
 508 static inline void
 509 uart_unlock_and_check_sysrq(struct uart_port *port, unsigned long irqflags)
 510 {
 511         spin_unlock_irqrestore(&port->lock, irqflags);
 512 }
 513 #endif
 514
 515 /*
 516  * We do the SysRQ and SAK checking like this...
 517  */
 518 static inline int uart_handle_break(struct uart_port *port)
 519 {
 520         struct uart_state *state = port->state;
 521
 522         if (port->handle_break)
 523                 port->handle_break(port);
 524
 525 #ifdef SUPPORT_SYSRQ
 526         if (port->cons && port->cons->index == port->line) {
 527                 if (!port->sysrq) {
 528                         port->sysrq = jiffies + HZ*5;
 529                         return 1;
 530                 }
 531                 port->sysrq = 0;
 532         }
 533 #endif
 534         if (port->flags & UPF_SAK)
 535                 do_SAK(state->port.tty);
 536         return 0;
 537 }
 538
 539 /*
 540  *      UART_ENABLE_MS - determine if port should enable modem status irqs
 541  */
 542 #define UART_ENABLE_MS(port,cflag)      ((port)->flags & UPF_HARDPPS_CD || \
 543                                          (cflag) & CRTSCTS || \
 544                                          !((cflag) & CLOCAL))
 545
 546 void uart_get_rs485_mode(struct device *dev, struct serial_rs485 *rs485conf);
 547 #endif /* LINUX_SERIAL_CORE_H */