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/driver-api/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         /* flags must be updated while holding port mutex */
 165         upf_t                   flags;
 166
 167         /*
 168          * These flags must be equivalent to the flags defined in
 169          * include/uapi/linux/tty_flags.h which are the userspace definitions
 170          * assigned from the serial_struct flags in uart_set_info()
 171          * [for bit definitions in the UPF_CHANGE_MASK]
 172          *
 173          * Bits [0..UPF_LAST_USER] are userspace defined/visible/changeable
 174          * The remaining bits are serial-core specific and not modifiable by
 175          * userspace.
 176          */
 177 #define UPF_FOURPORT            ((__force upf_t) ASYNC_FOURPORT       /* 1  */ )
 178 #define UPF_SAK                 ((__force upf_t) ASYNC_SAK            /* 2  */ )
 179 #define UPF_SPD_HI              ((__force upf_t) ASYNC_SPD_HI         /* 4  */ )
 180 #define UPF_SPD_VHI             ((__force upf_t) ASYNC_SPD_VHI        /* 5  */ )
 181 #define UPF_SPD_CUST            ((__force upf_t) ASYNC_SPD_CUST   /* 0x0030 */ )
 182 #define UPF_SPD_WARP            ((__force upf_t) ASYNC_SPD_WARP   /* 0x1010 */ )
 183 #define UPF_SPD_MASK            ((__force upf_t) ASYNC_SPD_MASK   /* 0x1030 */ )
 184 #define UPF_SKIP_TEST           ((__force upf_t) ASYNC_SKIP_TEST      /* 6  */ )
 185 #define UPF_AUTO_IRQ            ((__force upf_t) ASYNC_AUTO_IRQ       /* 7  */ )
 186 #define UPF_HARDPPS_CD          ((__force upf_t) ASYNC_HARDPPS_CD     /* 11 */ )
 187 #define UPF_SPD_SHI             ((__force upf_t) ASYNC_SPD_SHI        /* 12 */ )
 188 #define UPF_LOW_LATENCY         ((__force upf_t) ASYNC_LOW_LATENCY    /* 13 */ )
 189 #define UPF_BUGGY_UART          ((__force upf_t) ASYNC_BUGGY_UART     /* 14 */ )
 190 #define UPF_MAGIC_MULTIPLIER    ((__force upf_t) ASYNC_MAGIC_MULTIPLIER /* 16 */ )
 191
 192 #define UPF_NO_THRE_TEST        ((__force upf_t) (1 << 19))
 193 /* Port has hardware-assisted h/w flow control */
 194 #define UPF_AUTO_CTS            ((__force upf_t) (1 << 20))
 195 #define UPF_AUTO_RTS            ((__force upf_t) (1 << 21))
 196 #define UPF_HARD_FLOW           ((__force upf_t) (UPF_AUTO_CTS | UPF_AUTO_RTS))
 197 /* Port has hardware-assisted s/w flow control */
 198 #define UPF_SOFT_FLOW           ((__force upf_t) (1 << 22))
 199 #define UPF_CONS_FLOW           ((__force upf_t) (1 << 23))
 200 #define UPF_SHARE_IRQ           ((__force upf_t) (1 << 24))
 201 #define UPF_EXAR_EFR            ((__force upf_t) (1 << 25))
 202 #define UPF_BUG_THRE            ((__force upf_t) (1 << 26))
 203 /* The exact UART type is known and should not be probed.  */
 204 #define UPF_FIXED_TYPE          ((__force upf_t) (1 << 27))
 205 #define UPF_BOOT_AUTOCONF       ((__force upf_t) (1 << 28))
 206 #define UPF_FIXED_PORT          ((__force upf_t) (1 << 29))
 207 #define UPF_DEAD                ((__force upf_t) (1 << 30))
 208 #define UPF_IOREMAP             ((__force upf_t) (1 << 31))
 209
 210 #define __UPF_CHANGE_MASK       0x17fff
 211 #define UPF_CHANGE_MASK         ((__force upf_t) __UPF_CHANGE_MASK)
 212 #define UPF_USR_MASK            ((__force upf_t) (UPF_SPD_MASK|UPF_LOW_LATENCY))
 213
 214 #if __UPF_CHANGE_MASK > ASYNC_FLAGS
 215 #error Change mask not equivalent to userspace-visible bit defines
 216 #endif
 217
 218         /*
 219          * Must hold termios_rwsem, port mutex and port lock to change;
 220          * can hold any one lock to read.
 221          */
 222         upstat_t                status;
 223
 224 #define UPSTAT_CTS_ENABLE       ((__force upstat_t) (1 << 0))
 225 #define UPSTAT_DCD_ENABLE       ((__force upstat_t) (1 << 1))
 226 #define UPSTAT_AUTORTS          ((__force upstat_t) (1 << 2))
 227 #define UPSTAT_AUTOCTS          ((__force upstat_t) (1 << 3))
 228 #define UPSTAT_AUTOXOFF         ((__force upstat_t) (1 << 4))
 229 #define UPSTAT_SYNC_FIFO        ((__force upstat_t) (1 << 5))
 230
 231         int                     hw_stopped;             /* sw-assisted CTS flow state */
 232         unsigned int            mctrl;                  /* current modem ctrl settings */
 233         unsigned int            timeout;                /* character-based timeout */
 234         unsigned int            type;                   /* port type */
 235         const struct uart_ops   *ops;
 236         unsigned int            custom_divisor;
 237         unsigned int            line;                   /* port index */
 238         unsigned int            minor;
 239         resource_size_t         mapbase;                /* for ioremap */
 240         resource_size_t         mapsize;
 241         struct device           *dev;                   /* parent device */
 242
 243         unsigned long           sysrq;                  /* sysrq timeout */
 244         unsigned int            sysrq_ch;               /* char for sysrq */
 245         unsigned char           has_sysrq;
 246
 247         unsigned char           hub6;                   /* this should be in the 8250 driver */
 248         unsigned char           suspended;
 249         const char              *name;                  /* port name */
 250         struct attribute_group  *attr_group;            /* port specific attributes */
 251         const struct attribute_group **tty_groups;      /* all attributes (serial core use only) */
 252         struct serial_rs485     rs485;
 253         struct serial_iso7816   iso7816;
 254         void                    *private_data;          /* generic platform data pointer */
 255 };
 256
 257 static inline int serial_port_in(struct uart_port *up, int offset)
 258 {
 259         return up->serial_in(up, offset);
 260 }
 261
 262 static inline void serial_port_out(struct uart_port *up, int offset, int value)
 263 {
 264         up->serial_out(up, offset, value);
 265 }
 266
 267 /**
 268  * enum uart_pm_state - power states for UARTs
 269  * @UART_PM_STATE_ON: UART is powered, up and operational
 270  * @UART_PM_STATE_OFF: UART is powered off
 271  * @UART_PM_STATE_UNDEFINED: sentinel
 272  */
 273 enum uart_pm_state {
 274         UART_PM_STATE_ON = 0,
 275         UART_PM_STATE_OFF = 3, /* number taken from ACPI */
 276         UART_PM_STATE_UNDEFINED,
 277 };
 278
 279 /*
 280  * This is the state information which is persistent across opens.
 281  */
 282 struct uart_state {
 283         struct tty_port         port;
 284
 285         enum uart_pm_state      pm_state;
 286         struct circ_buf         xmit;
 287
 288         atomic_t                refcount;
 289         wait_queue_head_t       remove_wait;
 290         struct uart_port        *uart_port;
 291 };
 292
 293 #define UART_XMIT_SIZE  PAGE_SIZE
 294
 295
 296 /* number of characters left in xmit buffer before we ask for more */
 297 #define WAKEUP_CHARS            256
 298
 299 struct module;
 300 struct tty_driver;
 301
 302 struct uart_driver {
 303         struct module           *owner;
 304         const char              *driver_name;
 305         const char              *dev_name;
 306         int                      major;
 307         int                      minor;
 308         int                      nr;
 309         struct console          *cons;
 310
 311         /*
 312          * these are private; the low level driver should not
 313          * touch these; they should be initialised to NULL
 314          */
 315         struct uart_state       *state;
 316         struct tty_driver       *tty_driver;
 317 };
 318
 319 void uart_write_wakeup(struct uart_port *port);
 320
 321 /*
 322  * Baud rate helpers.
 323  */
 324 void uart_update_timeout(struct uart_port *port, unsigned int cflag,
 325                          unsigned int baud);
 326 unsigned int uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
 327                                 struct ktermios *old, unsigned int min,
 328                                 unsigned int max);
 329 unsigned int uart_get_divisor(struct uart_port *port, unsigned int baud);
 330
 331 /* Base timer interval for polling */
 332 static inline int uart_poll_timeout(struct uart_port *port)
 333 {
 334         int timeout = port->timeout;
 335
 336         return timeout > 6 ? (timeout / 2 - 2) : 1;
 337 }
 338
 339 /*
 340  * Console helpers.
 341  */
 342 struct earlycon_device {
 343         struct console *con;
 344         struct uart_port port;
 345         char options[16];               /* e.g., 115200n8 */
 346         unsigned int baud;
 347 };
 348
 349 struct earlycon_id {
 350         char    name[15];
 351         char    name_term;      /* In case compiler didn't '\0' term name */
 352         char    compatible[128];
 353         int     (*setup)(struct earlycon_device *, const char *options);
 354 };
 355
 356 extern const struct earlycon_id *__earlycon_table[];
 357 extern const struct earlycon_id *__earlycon_table_end[];
 358
 359 #if defined(CONFIG_SERIAL_EARLYCON) && !defined(MODULE)
 360 #define EARLYCON_USED_OR_UNUSED __used
 361 #else
 362 #define EARLYCON_USED_OR_UNUSED __maybe_unused
 363 #endif
 364
 365 #define _OF_EARLYCON_DECLARE(_name, compat, fn, unique_id)              \
 366         static const struct earlycon_id unique_id                       \
 367              EARLYCON_USED_OR_UNUSED __initconst                        \
 368                 = { .name = __stringify(_name),                         \
 369                     .compatible = compat,                               \
 370                     .setup = fn  };                                     \
 371         static const struct earlycon_id EARLYCON_USED_OR_UNUSED         \
 372                 __section(__earlycon_table)                             \
 373                 * const __PASTE(__p, unique_id) = &unique_id
 374
 375 #define OF_EARLYCON_DECLARE(_name, compat, fn)                          \
 376         _OF_EARLYCON_DECLARE(_name, compat, fn,                         \
 377                              __UNIQUE_ID(__earlycon_##_name))
 378
 379 #define EARLYCON_DECLARE(_name, fn)     OF_EARLYCON_DECLARE(_name, "", fn)
 380
 381 extern int of_setup_earlycon(const struct earlycon_id *match,
 382                              unsigned long node,
 383                              const char *options);
 384
 385 #ifdef CONFIG_SERIAL_EARLYCON
 386 extern bool earlycon_acpi_spcr_enable __initdata;
 387 int setup_earlycon(char *buf);
 388 #else
 389 static const bool earlycon_acpi_spcr_enable EARLYCON_USED_OR_UNUSED;
 390 static inline int setup_earlycon(char *buf) { return 0; }
 391 #endif
 392
 393 struct uart_port *uart_get_console(struct uart_port *ports, int nr,
 394                                    struct console *c);
 395 int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
 396                         char **options);
 397 void uart_parse_options(const char *options, int *baud, int *parity, int *bits,
 398                         int *flow);
 399 int uart_set_options(struct uart_port *port, struct console *co, int baud,
 400                      int parity, int bits, int flow);
 401 struct tty_driver *uart_console_device(struct console *co, int *index);
 402 void uart_console_write(struct uart_port *port, const char *s,
 403                         unsigned int count,
 404                         void (*putchar)(struct uart_port *, int));
 405
 406 /*
 407  * Port/driver registration/removal
 408  */
 409 int uart_register_driver(struct uart_driver *uart);
 410 void uart_unregister_driver(struct uart_driver *uart);
 411 int uart_add_one_port(struct uart_driver *reg, struct uart_port *port);
 412 int uart_remove_one_port(struct uart_driver *reg, struct uart_port *port);
 413 int uart_match_port(struct uart_port *port1, 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->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 extern int uart_handle_sysrq_char(struct uart_port *port, unsigned int ch);
 463 extern int uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch);
 464 extern void uart_unlock_and_check_sysrq(struct uart_port *port,
 465                                         unsigned long irqflags);
 466 extern int uart_handle_break(struct uart_port *port);
 467
 468 /*
 469  *      UART_ENABLE_MS - determine if port should enable modem status irqs
 470  */
 471 #define UART_ENABLE_MS(port,cflag)      ((port)->flags & UPF_HARDPPS_CD || \
 472                                          (cflag) & CRTSCTS || \
 473                                          !((cflag) & CLOCAL))
 474
 475 void uart_get_rs485_mode(struct device *dev, struct serial_rs485 *rs485conf);
 476 #endif /* LINUX_SERIAL_CORE_H */