include/linux/serial_core.h

   1 /*
   2  *  linux/drivers/char/serial_core.h
   3  *
   4  *  Copyright (C) 2000 Deep Blue Solutions Ltd.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20 #ifndef LINUX_SERIAL_CORE_H
  21 #define LINUX_SERIAL_CORE_H
  22
  23 #include <linux/bitops.h>
  24 #include <linux/compiler.h>
  25 #include <linux/interrupt.h>
  26 #include <linux/circ_buf.h>
  27 #include <linux/spinlock.h>
  28 #include <linux/sched.h>
  29 #include <linux/tty.h>
  30 #include <linux/mutex.h>
  31 #include <linux/sysrq.h>
  32 #include <uapi/linux/serial_core.h>
  33
  34 #ifdef CONFIG_SERIAL_CORE_CONSOLE
  35 #define uart_console(port) \
  36         ((port)->cons && (port)->cons->index == (port)->line)
  37 #else
  38 #define uart_console(port)      ({ (void)port; 0; })
  39 #endif
  40
  41 struct uart_port;
  42 struct serial_struct;
  43 struct device;
  44
  45 /*
  46  * This structure describes all the operations that can be done on the
  47  * physical hardware.  See Documentation/serial/driver for details.
  48  */
  49 struct uart_ops {
  50         unsigned int    (*tx_empty)(struct uart_port *);
  51         void            (*set_mctrl)(struct uart_port *, unsigned int mctrl);
  52         unsigned int    (*get_mctrl)(struct uart_port *);
  53         void            (*stop_tx)(struct uart_port *);
  54         void            (*start_tx)(struct uart_port *);
  55         void            (*throttle)(struct uart_port *);
  56         void            (*unthrottle)(struct uart_port *);
  57         void            (*send_xchar)(struct uart_port *, char ch);
  58         void            (*stop_rx)(struct uart_port *);
  59         void            (*enable_ms)(struct uart_port *);
  60         void            (*break_ctl)(struct uart_port *, int ctl);
  61         int             (*startup)(struct uart_port *);
  62         void            (*shutdown)(struct uart_port *);
  63         void            (*flush_buffer)(struct uart_port *);
  64         void            (*set_termios)(struct uart_port *, struct ktermios *new,
  65                                        struct ktermios *old);
  66         void            (*set_ldisc)(struct uart_port *, struct ktermios *);
  67         void            (*pm)(struct uart_port *, unsigned int state,
  68                               unsigned int oldstate);
  69
  70         /*
  71          * Return a string describing the type of the port
  72          */
  73         const char      *(*type)(struct uart_port *);
  74
  75         /*
  76          * Release IO and memory resources used by the port.
  77          * This includes iounmap if necessary.
  78          */
  79         void            (*release_port)(struct uart_port *);
  80
  81         /*
  82          * Request IO and memory resources used by the port.
  83          * This includes iomapping the port if necessary.
  84          */
  85         int             (*request_port)(struct uart_port *);
  86         void            (*config_port)(struct uart_port *, int);
  87         int             (*verify_port)(struct uart_port *, struct serial_struct *);
  88         int             (*ioctl)(struct uart_port *, unsigned int, unsigned long);
  89 #ifdef CONFIG_CONSOLE_POLL
  90         int             (*poll_init)(struct uart_port *);
  91         void            (*poll_put_char)(struct uart_port *, unsigned char);
  92         int             (*poll_get_char)(struct uart_port *);
  93 #endif
  94 };
  95
  96 #define NO_POLL_CHAR            0x00ff0000
  97 #define UART_CONFIG_TYPE        (1 << 0)
  98 #define UART_CONFIG_IRQ         (1 << 1)
  99
 100 struct uart_icount {
 101         __u32   cts;
 102         __u32   dsr;
 103         __u32   rng;
 104         __u32   dcd;
 105         __u32   rx;
 106         __u32   tx;
 107         __u32   frame;
 108         __u32   overrun;
 109         __u32   parity;
 110         __u32   brk;
 111         __u32   buf_overrun;
 112 };
 113
 114 typedef unsigned int __bitwise upf_t;
 115 typedef unsigned int __bitwise upstat_t;
 116
 117 struct uart_port {
 118         spinlock_t              lock;                   /* port lock */
 119         unsigned long           iobase;                 /* in/out[bwl] */
 120         unsigned char __iomem   *membase;               /* read/write[bwl] */
 121         unsigned int            (*serial_in)(struct uart_port *, int);
 122         void                    (*serial_out)(struct uart_port *, int, int);
 123         void                    (*set_termios)(struct uart_port *,
 124                                                struct ktermios *new,
 125                                                struct ktermios *old);
 126         void                    (*set_ldisc)(struct uart_port *,
 127                                              struct ktermios *);
 128         unsigned int            (*get_mctrl)(struct uart_port *);
 129         void                    (*set_mctrl)(struct uart_port *, unsigned int);
 130         unsigned int            (*get_divisor)(struct uart_port *,
 131                                                unsigned int baud,
 132                                                unsigned int *frac);
 133         void                    (*set_divisor)(struct uart_port *,
 134                                                unsigned int baud,
 135                                                unsigned int quot,
 136                                                unsigned int quot_frac);
 137         int                     (*startup)(struct uart_port *port);
 138         void                    (*shutdown)(struct uart_port *port);
 139         void                    (*throttle)(struct uart_port *port);
 140         void                    (*unthrottle)(struct uart_port *port);
 141         int                     (*handle_irq)(struct uart_port *);
 142         void                    (*pm)(struct uart_port *, unsigned int state,
 143                                       unsigned int old);
 144         void                    (*handle_break)(struct uart_port *);
 145         int                     (*rs485_config)(struct uart_port *,
 146                                                 struct serial_rs485 *rs485);
 147         int                     (*iso7816_config)(struct uart_port *,
 148                                                   struct serial_iso7816 *iso7816);
 149         unsigned int            irq;                    /* irq number */
 150         unsigned long           irqflags;               /* irq flags  */
 151         unsigned int            uartclk;                /* base uart clock */
 152         unsigned int            fifosize;               /* tx fifo size */
 153         unsigned char           x_char;                 /* xon/xoff char */
 154         unsigned char           regshift;               /* reg offset shift */
 155         unsigned char           iotype;                 /* io access style */
 156         unsigned char           quirks;                 /* internal quirks */
 157
 158 #define UPIO_PORT               (SERIAL_IO_PORT)        /* 8b I/O port access */
 159 #define UPIO_HUB6               (SERIAL_IO_HUB6)        /* Hub6 ISA card */
 160 #define UPIO_MEM                (SERIAL_IO_MEM)         /* driver-specific */
 161 #define UPIO_MEM32              (SERIAL_IO_MEM32)       /* 32b little endian */
 162 #define UPIO_AU                 (SERIAL_IO_AU)          /* Au1x00 and RT288x type IO */
 163 #define UPIO_TSI                (SERIAL_IO_TSI)         /* Tsi108/109 type IO */
 164 #define UPIO_MEM32BE            (SERIAL_IO_MEM32BE)     /* 32b big endian */
 165 #define UPIO_MEM16              (SERIAL_IO_MEM16)       /* 16b little endian */
 166
 167         /* quirks must be updated while holding port mutex */
 168 #define UPQ_NO_TXEN_TEST        BIT(0)
 169
 170         unsigned int            read_status_mask;       /* driver specific */
 171         unsigned int            ignore_status_mask;     /* driver specific */
 172         struct uart_state       *state;                 /* pointer to parent state */
 173         struct uart_icount      icount;                 /* statistics */
 174
 175         struct console          *cons;                  /* struct console, if any */
 176 #if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(SUPPORT_SYSRQ)
 177         unsigned long           sysrq;                  /* sysrq timeout */
 178 #endif
 179
 180         /* flags must be updated while holding port mutex */
 181         upf_t                   flags;
 182
 183         /*
 184          * These flags must be equivalent to the flags defined in
 185          * include/uapi/linux/tty_flags.h which are the userspace definitions
 186          * assigned from the serial_struct flags in uart_set_info()
 187          * [for bit definitions in the UPF_CHANGE_MASK]
 188          *
 189          * Bits [0..UPF_LAST_USER] are userspace defined/visible/changeable
 190          * The remaining bits are serial-core specific and not modifiable by
 191          * userspace.
 192          */
 193 #define UPF_FOURPORT            ((__force upf_t) ASYNC_FOURPORT       /* 1  */ )
 194 #define UPF_SAK                 ((__force upf_t) ASYNC_SAK            /* 2  */ )
 195 #define UPF_SPD_HI              ((__force upf_t) ASYNC_SPD_HI         /* 4  */ )
 196 #define UPF_SPD_VHI             ((__force upf_t) ASYNC_SPD_VHI        /* 5  */ )
 197 #define UPF_SPD_CUST            ((__force upf_t) ASYNC_SPD_CUST   /* 0x0030 */ )
 198 #define UPF_SPD_WARP            ((__force upf_t) ASYNC_SPD_WARP   /* 0x1010 */ )
 199 #define UPF_SPD_MASK            ((__force upf_t) ASYNC_SPD_MASK   /* 0x1030 */ )
 200 #define UPF_SKIP_TEST           ((__force upf_t) ASYNC_SKIP_TEST      /* 6  */ )
 201 #define UPF_AUTO_IRQ            ((__force upf_t) ASYNC_AUTO_IRQ       /* 7  */ )
 202 #define UPF_HARDPPS_CD          ((__force upf_t) ASYNC_HARDPPS_CD     /* 11 */ )
 203 #define UPF_SPD_SHI             ((__force upf_t) ASYNC_SPD_SHI        /* 12 */ )
 204 #define UPF_LOW_LATENCY         ((__force upf_t) ASYNC_LOW_LATENCY    /* 13 */ )
 205 #define UPF_BUGGY_UART          ((__force upf_t) ASYNC_BUGGY_UART     /* 14 */ )
 206 #define UPF_MAGIC_MULTIPLIER    ((__force upf_t) ASYNC_MAGIC_MULTIPLIER /* 16 */ )
 207
 208 #define UPF_NO_THRE_TEST        ((__force upf_t) (1 << 19))
 209 /* Port has hardware-assisted h/w flow control */
 210 #define UPF_AUTO_CTS            ((__force upf_t) (1 << 20))
 211 #define UPF_AUTO_RTS            ((__force upf_t) (1 << 21))
 212 #define UPF_HARD_FLOW           ((__force upf_t) (UPF_AUTO_CTS | UPF_AUTO_RTS))
 213 /* Port has hardware-assisted s/w flow control */
 214 #define UPF_SOFT_FLOW           ((__force upf_t) (1 << 22))
 215 #define UPF_CONS_FLOW           ((__force upf_t) (1 << 23))
 216 #define UPF_SHARE_IRQ           ((__force upf_t) (1 << 24))
 217 #define UPF_EXAR_EFR            ((__force upf_t) (1 << 25))
 218 #define UPF_BUG_THRE            ((__force upf_t) (1 << 26))
 219 /* The exact UART type is known and should not be probed.  */
 220 #define UPF_FIXED_TYPE          ((__force upf_t) (1 << 27))
 221 #define UPF_BOOT_AUTOCONF       ((__force upf_t) (1 << 28))
 222 #define UPF_FIXED_PORT          ((__force upf_t) (1 << 29))
 223 #define UPF_DEAD                ((__force upf_t) (1 << 30))
 224 #define UPF_IOREMAP             ((__force upf_t) (1 << 31))
 225
 226 #define __UPF_CHANGE_MASK       0x17fff
 227 #define UPF_CHANGE_MASK         ((__force upf_t) __UPF_CHANGE_MASK)
 228 #define UPF_USR_MASK            ((__force upf_t) (UPF_SPD_MASK|UPF_LOW_LATENCY))
 229
 230 #if __UPF_CHANGE_MASK > ASYNC_FLAGS
 231 #error Change mask not equivalent to userspace-visible bit defines
 232 #endif
 233
 234         /*
 235          * Must hold termios_rwsem, port mutex and port lock to change;
 236          * can hold any one lock to read.
 237          */
 238         upstat_t                status;
 239
 240 #define UPSTAT_CTS_ENABLE       ((__force upstat_t) (1 << 0))
 241 #define UPSTAT_DCD_ENABLE       ((__force upstat_t) (1 << 1))
 242 #define UPSTAT_AUTORTS          ((__force upstat_t) (1 << 2))
 243 #define UPSTAT_AUTOCTS          ((__force upstat_t) (1 << 3))
 244 #define UPSTAT_AUTOXOFF         ((__force upstat_t) (1 << 4))
 245 #define UPSTAT_SYNC_FIFO        ((__force upstat_t) (1 << 5))
 246
 247         int                     hw_stopped;             /* sw-assisted CTS flow state */
 248         unsigned int            mctrl;                  /* current modem ctrl settings */
 249         unsigned int            timeout;                /* character-based timeout */
 250         unsigned int            type;                   /* port type */
 251         const struct uart_ops   *ops;
 252         unsigned int            custom_divisor;
 253         unsigned int            line;                   /* port index */
 254         unsigned int            minor;
 255         resource_size_t         mapbase;                /* for ioremap */
 256         resource_size_t         mapsize;
 257         struct device           *dev;                   /* parent device */
 258         unsigned char           hub6;                   /* this should be in the 8250 driver */
 259         unsigned char           suspended;
 260         unsigned char           unused[2];
 261         const char              *name;                  /* port name */
 262         struct attribute_group  *attr_group;            /* port specific attributes */
 263         const struct attribute_group **tty_groups;      /* all attributes (serial core use only) */
 264         struct serial_rs485     rs485;
 265         struct serial_iso7816   iso7816;
 266         void                    *private_data;          /* generic platform data pointer */
 267 };
 268
 269 static inline int serial_port_in(struct uart_port *up, int offset)
 270 {
 271         return up->serial_in(up, offset);
 272 }
 273
 274 static inline void serial_port_out(struct uart_port *up, int offset, int value)
 275 {
 276         up->serial_out(up, offset, value);
 277 }
 278
 279 /**
 280  * enum uart_pm_state - power states for UARTs
 281  * @UART_PM_STATE_ON: UART is powered, up and operational
 282  * @UART_PM_STATE_OFF: UART is powered off
 283  * @UART_PM_STATE_UNDEFINED: sentinel
 284  */
 285 enum uart_pm_state {
 286         UART_PM_STATE_ON = 0,
 287         UART_PM_STATE_OFF = 3, /* number taken from ACPI */
 288         UART_PM_STATE_UNDEFINED,
 289 };
 290
 291 /*
 292  * This is the state information which is persistent across opens.
 293  */
 294 struct uart_state {
 295         struct tty_port         port;
 296
 297         enum uart_pm_state      pm_state;
 298         struct circ_buf         xmit;
 299
 300         atomic_t                refcount;
 301         wait_queue_head_t       remove_wait;
 302         struct uart_port        *uart_port;
 303 };
 304
 305 #define UART_XMIT_SIZE  PAGE_SIZE
 306
 307
 308 /* number of characters left in xmit buffer before we ask for more */
 309 #define WAKEUP_CHARS            256
 310
 311 struct module;
 312 struct tty_driver;
 313
 314 struct uart_driver {
 315         struct module           *owner;
 316         const char              *driver_name;
 317         const char              *dev_name;
 318         int                      major;
 319         int                      minor;
 320         int                      nr;
 321         struct console          *cons;
 322
 323         /*
 324          * these are private; the low level driver should not
 325          * touch these; they should be initialised to NULL
 326          */
 327         struct uart_state       *state;
 328         struct tty_driver       *tty_driver;
 329 };
 330
 331 void uart_write_wakeup(struct uart_port *port);
 332
 333 /*
 334  * Baud rate helpers.
 335  */
 336 void uart_update_timeout(struct uart_port *port, unsigned int cflag,
 337                          unsigned int baud);
 338 unsigned int uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
 339                                 struct ktermios *old, unsigned int min,
 340                                 unsigned int max);
 341 unsigned int uart_get_divisor(struct uart_port *port, unsigned int baud);
 342
 343 /* Base timer interval for polling */
 344 static inline int uart_poll_timeout(struct uart_port *port)
 345 {
 346         int timeout = port->timeout;
 347
 348         return timeout > 6 ? (timeout / 2 - 2) : 1;
 349 }
 350
 351 /*
 352  * Console helpers.
 353  */
 354 struct earlycon_device {
 355         struct console *con;
 356         struct uart_port port;
 357         char options[16];               /* e.g., 115200n8 */
 358         unsigned int baud;
 359 };
 360
 361 struct earlycon_id {
 362         char    name[15];
 363         char    name_term;      /* In case compiler didn't '\0' term name */
 364         char    compatible[128];
 365         int     (*setup)(struct earlycon_device *, const char *options);
 366 };
 367
 368 extern const struct earlycon_id *__earlycon_table[];
 369 extern const struct earlycon_id *__earlycon_table_end[];
 370
 371 #if defined(CONFIG_SERIAL_EARLYCON) && !defined(MODULE)
 372 #define EARLYCON_USED_OR_UNUSED __used
 373 #else
 374 #define EARLYCON_USED_OR_UNUSED __maybe_unused
 375 #endif
 376
 377 #define _OF_EARLYCON_DECLARE(_name, compat, fn, unique_id)              \
 378         static const struct earlycon_id unique_id                       \
 379              EARLYCON_USED_OR_UNUSED __initconst                        \
 380                 = { .name = __stringify(_name),                         \
 381                     .compatible = compat,                               \
 382                     .setup = fn  };                                     \
 383         static const struct earlycon_id EARLYCON_USED_OR_UNUSED         \
 384                 __section(__earlycon_table)                             \
 385                 * const __PASTE(__p, unique_id) = &unique_id
 386
 387 #define OF_EARLYCON_DECLARE(_name, compat, fn)                          \
 388         _OF_EARLYCON_DECLARE(_name, compat, fn,                         \
 389                              __UNIQUE_ID(__earlycon_##_name))
 390
 391 #define EARLYCON_DECLARE(_name, fn)     OF_EARLYCON_DECLARE(_name, "", fn)
 392
 393 extern int of_setup_earlycon(const struct earlycon_id *match,
 394                              unsigned long node,
 395                              const char *options);
 396
 397 #ifdef CONFIG_SERIAL_EARLYCON
 398 extern bool earlycon_acpi_spcr_enable __initdata;
 399 int setup_earlycon(char *buf);
 400 #else
 401 static const bool earlycon_acpi_spcr_enable EARLYCON_USED_OR_UNUSED;
 402 static inline int setup_earlycon(char *buf) { return 0; }
 403 #endif
 404
 405 struct uart_port *uart_get_console(struct uart_port *ports, int nr,
 406                                    struct console *c);
 407 int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
 408                         char **options);
 409 void uart_parse_options(const char *options, int *baud, int *parity, int *bits,
 410                         int *flow);
 411 int uart_set_options(struct uart_port *port, struct console *co, int baud,
 412                      int parity, int bits, int flow);
 413 struct tty_driver *uart_console_device(struct console *co, int *index);
 414 void uart_console_write(struct uart_port *port, const char *s,
 415                         unsigned int count,
 416                         void (*putchar)(struct uart_port *, int));
 417
 418 /*
 419  * Port/driver registration/removal
 420  */
 421 int uart_register_driver(struct uart_driver *uart);
 422 void uart_unregister_driver(struct uart_driver *uart);
 423 int uart_add_one_port(struct uart_driver *reg, struct uart_port *port);
 424 int uart_remove_one_port(struct uart_driver *reg, struct uart_port *port);
 425 int uart_match_port(struct uart_port *port1, struct uart_port *port2);
 426
 427 /*
 428  * Power Management
 429  */
 430 int uart_suspend_port(struct uart_driver *reg, struct uart_port *port);
 431 int uart_resume_port(struct uart_driver *reg, struct uart_port *port);
 432
 433 #define uart_circ_empty(circ)           ((circ)->head == (circ)->tail)
 434 #define uart_circ_clear(circ)           ((circ)->head = (circ)->tail = 0)
 435
 436 #define uart_circ_chars_pending(circ)   \
 437         (CIRC_CNT((circ)->head, (circ)->tail, UART_XMIT_SIZE))
 438
 439 #define uart_circ_chars_free(circ)      \
 440         (CIRC_SPACE((circ)->head, (circ)->tail, UART_XMIT_SIZE))
 441
 442 static inline int uart_tx_stopped(struct uart_port *port)
 443 {
 444         struct tty_struct *tty = port->state->port.tty;
 445         if ((tty && tty->stopped) || port->hw_stopped)
 446                 return 1;
 447         return 0;
 448 }
 449
 450 static inline bool uart_cts_enabled(struct uart_port *uport)
 451 {
 452         return !!(uport->status & UPSTAT_CTS_ENABLE);
 453 }
 454
 455 static inline bool uart_softcts_mode(struct uart_port *uport)
 456 {
 457         upstat_t mask = UPSTAT_CTS_ENABLE | UPSTAT_AUTOCTS;
 458
 459         return ((uport->status & mask) == UPSTAT_CTS_ENABLE);
 460 }
 461
 462 /*
 463  * The following are helper functions for the low level drivers.
 464  */
 465
 466 extern void uart_handle_dcd_change(struct uart_port *uport,
 467                 unsigned int status);
 468 extern void uart_handle_cts_change(struct uart_port *uport,
 469                 unsigned int status);
 470
 471 extern void uart_insert_char(struct uart_port *port, unsigned int status,
 472                  unsigned int overrun, unsigned int ch, unsigned int flag);
 473
 474 #if defined(SUPPORT_SYSRQ) && defined(CONFIG_MAGIC_SYSRQ_SERIAL)
 475 static inline int
 476 uart_handle_sysrq_char(struct uart_port *port, unsigned int ch)
 477 {
 478         if (port->sysrq) {
 479                 if (ch && time_before(jiffies, port->sysrq)) {
 480                         handle_sysrq(ch);
 481                         port->sysrq = 0;
 482                         return 1;
 483                 }
 484                 port->sysrq = 0;
 485         }
 486         return 0;
 487 }
 488 #else
 489 #define uart_handle_sysrq_char(port,ch) ({ (void)port; 0; })
 490 #endif
 491
 492 /*
 493  * We do the SysRQ and SAK checking like this...
 494  */
 495 static inline int uart_handle_break(struct uart_port *port)
 496 {
 497         struct uart_state *state = port->state;
 498
 499         if (port->handle_break)
 500                 port->handle_break(port);
 501
 502 #ifdef SUPPORT_SYSRQ
 503         if (port->cons && port->cons->index == port->line) {
 504                 if (!port->sysrq) {
 505                         port->sysrq = jiffies + HZ*5;
 506                         return 1;
 507                 }
 508                 port->sysrq = 0;
 509         }
 510 #endif
 511         if (port->flags & UPF_SAK)
 512                 do_SAK(state->port.tty);
 513         return 0;
 514 }
 515
 516 /*
 517  *      UART_ENABLE_MS - determine if port should enable modem status irqs
 518  */
 519 #define UART_ENABLE_MS(port,cflag)      ((port)->flags & UPF_HARDPPS_CD || \
 520                                          (cflag) & CRTSCTS || \
 521                                          !((cflag) & CLOCAL))
 522
 523 void uart_get_rs485_mode(struct device *dev, struct serial_rs485 *rs485conf);
 524 #endif /* LINUX_SERIAL_CORE_H */