LXR linux/include/linux/serial

   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
  29struct uart_port;
  30struct serial_struct;
  31struct device;
  32
  33/*
  34 * This structure describes all the operations that can be done on the
  35 * physical hardware.  See Documentation/driver-api/serial/driver.rst for details.
  36 */
  37struct 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
  88struct 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
 102typedef unsigned int __bitwise upf_t;
 103typedef unsigned int __bitwise upstat_t;
 104
 105struct 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
 258static inline int serial_port_in(struct uart_port *up, int offset)
 259{
 260        return up->serial_in(up, offset);
 261}
 262
 263static 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 */
 274enum 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 */
 283struct 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
 300struct module;
 301struct tty_driver;
 302
 303struct 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
 320void uart_write_wakeup(struct uart_port *port);
 321
 322/*
 323 * Baud rate helpers.
 324 */
 325void uart_update_timeout(struct uart_port *port, unsigned int cflag,
 326                         unsigned int baud);
 327unsigned int uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
 328                                struct ktermios *old, unsigned int min,
 329                                unsigned int max);
 330unsigned int uart_get_divisor(struct uart_port *port, unsigned int baud);
 331
 332/* Base timer interval for polling */
 333static 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 */
 343struct earlycon_device {
 344        struct console *con;
 345        struct uart_port port;
 346        char options[16];               /* e.g., 115200n8 */
 347        unsigned int baud;
 348};
 349
 350struct 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
 357extern const struct earlycon_id *__earlycon_table[];
 358extern 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
 382extern int of_setup_earlycon(const struct earlycon_id *match,
 383                             unsigned long node,
 384                             const char *options);
 385
 386#ifdef CONFIG_SERIAL_EARLYCON
 387extern bool earlycon_acpi_spcr_enable __initdata;
 388int setup_earlycon(char *buf);
 389#else
 390static const bool earlycon_acpi_spcr_enable EARLYCON_USED_OR_UNUSED;
 391static inline int setup_earlycon(char *buf) { return 0; }
 392#endif
 393
 394struct uart_port *uart_get_console(struct uart_port *ports, int nr,
 395                                   struct console *c);
 396int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
 397                        char **options);
 398void uart_parse_options(const char *options, int *baud, int *parity, int *bits,
 399                        int *flow);
 400int uart_set_options(struct uart_port *port, struct console *co, int baud,
 401                     int parity, int bits, int flow);
 402struct tty_driver *uart_console_device(struct console *co, int *index);
 403void 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 */
 410int uart_register_driver(struct uart_driver *uart);
 411void uart_unregister_driver(struct uart_driver *uart);
 412int uart_add_one_port(struct uart_driver *reg, struct uart_port *port);
 413int uart_remove_one_port(struct uart_driver *reg, struct uart_port *port);
 414int uart_match_port(struct uart_port *port1, struct uart_port *port2);
 415
 416/*
 417 * Power Management
 418 */
 419int uart_suspend_port(struct uart_driver *reg, struct uart_port *port);
 420int 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
 431static 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
 439static inline bool uart_cts_enabled(struct uart_port *uport)
 440{
 441        return !!(uport->status & UPSTAT_CTS_ENABLE);
 442}
 443
 444static 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
 455extern void uart_handle_dcd_change(struct uart_port *uport,
 456                unsigned int status);
 457extern void uart_handle_cts_change(struct uart_port *uport,
 458                unsigned int status);
 459
 460extern 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)
 464static inline int
 465uart_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}
 477static inline int
 478uart_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}
 490static inline void
 491uart_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
 504static inline int
 505uart_handle_sysrq_char(struct uart_port *port, unsigned int ch) { return 0; }
 506static inline int
 507uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch) { return 0; }
 508static inline void
 509uart_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 */
 518static 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
 546void uart_get_rs485_mode(struct device *dev, struct serial_rs485 *rs485conf);
 547#endif /* LINUX_SERIAL_CORE_H */
 548