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
  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         int                     (*startup)(struct uart_port *port);
 131         void                    (*shutdown)(struct uart_port *port);
 132         void                    (*throttle)(struct uart_port *port);
 133         void                    (*unthrottle)(struct uart_port *port);
 134         int                     (*handle_irq)(struct uart_port *);
 135         void                    (*pm)(struct uart_port *, unsigned int state,
 136                                       unsigned int old);
 137         void                    (*handle_break)(struct uart_port *);
 138         int                     (*rs485_config)(struct uart_port *,
 139                                                 struct serial_rs485 *rs485);
 140         unsigned int            irq;                    /* irq number */
 141         unsigned long           irqflags;               /* irq flags  */
 142         unsigned int            uartclk;                /* base uart clock */
 143         unsigned int            fifosize;               /* tx fifo size */
 144         unsigned char           x_char;                 /* xon/xoff char */
 145         unsigned char           regshift;               /* reg offset shift */
 146         unsigned char           iotype;                 /* io access style */
 147         unsigned char           unused1;
 148
 149 #define UPIO_PORT               (SERIAL_IO_PORT)        /* 8b I/O port access */
 150 #define UPIO_HUB6               (SERIAL_IO_HUB6)        /* Hub6 ISA card */
 151 #define UPIO_MEM                (SERIAL_IO_MEM)         /* driver-specific */
 152 #define UPIO_MEM32              (SERIAL_IO_MEM32)       /* 32b little endian */
 153 #define UPIO_AU                 (SERIAL_IO_AU)          /* Au1x00 and RT288x type IO */
 154 #define UPIO_TSI                (SERIAL_IO_TSI)         /* Tsi108/109 type IO */
 155 #define UPIO_MEM32BE            (SERIAL_IO_MEM32BE)     /* 32b big endian */
 156 #define UPIO_MEM16              (SERIAL_IO_MEM16)       /* 16b little endian */
 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 #endif
 167
 168         /* flags must be updated while holding port mutex */
 169         upf_t                   flags;
 170
 171         /*
 172          * These flags must be equivalent to the flags defined in
 173          * include/uapi/linux/tty_flags.h which are the userspace definitions
 174          * assigned from the serial_struct flags in uart_set_info()
 175          * [for bit definitions in the UPF_CHANGE_MASK]
 176          *
 177          * Bits [0..UPF_LAST_USER] are userspace defined/visible/changeable
 178          * except bit 15 (UPF_NO_TXEN_TEST) which is masked off.
 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_NO_TXEN_TEST        ((__force upf_t) (1 << 15))
 196 #define UPF_MAGIC_MULTIPLIER    ((__force upf_t) ASYNC_MAGIC_MULTIPLIER /* 16 */ )
 197
 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
 235         int                     hw_stopped;             /* sw-assisted CTS flow state */
 236         unsigned int            mctrl;                  /* current modem ctrl settings */
 237         unsigned int            timeout;                /* character-based timeout */
 238         unsigned int            type;                   /* port type */
 239         const struct uart_ops   *ops;
 240         unsigned int            custom_divisor;
 241         unsigned int            line;                   /* port index */
 242         unsigned int            minor;
 243         resource_size_t         mapbase;                /* for ioremap */
 244         resource_size_t         mapsize;
 245         struct device           *dev;                   /* parent device */
 246         unsigned char           hub6;                   /* this should be in the 8250 driver */
 247         unsigned char           suspended;
 248         unsigned char           irq_wake;
 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         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[16];
 351         char    compatible[128];
 352         int     (*setup)(struct earlycon_device *, const char *options);
 353 } __aligned(32);
 354
 355 extern const struct earlycon_id __earlycon_table[];
 356 extern const struct earlycon_id __earlycon_table_end[];
 357
 358 #if defined(CONFIG_SERIAL_EARLYCON) && !defined(MODULE)
 359 #define EARLYCON_USED_OR_UNUSED __used
 360 #else
 361 #define EARLYCON_USED_OR_UNUSED __maybe_unused
 362 #endif
 363
 364 #define OF_EARLYCON_DECLARE(_name, compat, fn)                          \
 365         static const struct earlycon_id __UNIQUE_ID(__earlycon_##_name) \
 366              EARLYCON_USED_OR_UNUSED __section(__earlycon_table)        \
 367                 = { .name = __stringify(_name),                         \
 368                     .compatible = compat,                               \
 369                     .setup = fn  }
 370
 371 #define EARLYCON_DECLARE(_name, fn)     OF_EARLYCON_DECLARE(_name, "", fn)
 372
 373 extern int of_setup_earlycon(const struct earlycon_id *match,
 374                              unsigned long node,
 375                              const char *options);
 376
 377 #ifdef CONFIG_SERIAL_EARLYCON
 378 extern bool earlycon_init_is_deferred __initdata;
 379 int setup_earlycon(char *buf);
 380 #else
 381 static const bool earlycon_init_is_deferred;
 382 static inline int setup_earlycon(char *buf) { return 0; }
 383 #endif
 384
 385 struct uart_port *uart_get_console(struct uart_port *ports, int nr,
 386                                    struct console *c);
 387 int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
 388                         char **options);
 389 void uart_parse_options(char *options, int *baud, int *parity, int *bits,
 390                         int *flow);
 391 int uart_set_options(struct uart_port *port, struct console *co, int baud,
 392                      int parity, int bits, int flow);
 393 struct tty_driver *uart_console_device(struct console *co, int *index);
 394 void uart_console_write(struct uart_port *port, const char *s,
 395                         unsigned int count,
 396                         void (*putchar)(struct uart_port *, int));
 397
 398 /*
 399  * Port/driver registration/removal
 400  */
 401 int uart_register_driver(struct uart_driver *uart);
 402 void uart_unregister_driver(struct uart_driver *uart);
 403 int uart_add_one_port(struct uart_driver *reg, struct uart_port *port);
 404 int uart_remove_one_port(struct uart_driver *reg, struct uart_port *port);
 405 int uart_match_port(struct uart_port *port1, struct uart_port *port2);
 406
 407 /*
 408  * Power Management
 409  */
 410 int uart_suspend_port(struct uart_driver *reg, struct uart_port *port);
 411 int uart_resume_port(struct uart_driver *reg, struct uart_port *port);
 412
 413 #define uart_circ_empty(circ)           ((circ)->head == (circ)->tail)
 414 #define uart_circ_clear(circ)           ((circ)->head = (circ)->tail = 0)
 415
 416 #define uart_circ_chars_pending(circ)   \
 417         (CIRC_CNT((circ)->head, (circ)->tail, UART_XMIT_SIZE))
 418
 419 #define uart_circ_chars_free(circ)      \
 420         (CIRC_SPACE((circ)->head, (circ)->tail, UART_XMIT_SIZE))
 421
 422 static inline int uart_tx_stopped(struct uart_port *port)
 423 {
 424         struct tty_struct *tty = port->state->port.tty;
 425         if ((tty && tty->stopped) || port->hw_stopped)
 426                 return 1;
 427         return 0;
 428 }
 429
 430 static inline bool uart_cts_enabled(struct uart_port *uport)
 431 {
 432         return !!(uport->status & UPSTAT_CTS_ENABLE);
 433 }
 434
 435 static inline bool uart_softcts_mode(struct uart_port *uport)
 436 {
 437         upstat_t mask = UPSTAT_CTS_ENABLE | UPSTAT_AUTOCTS;
 438
 439         return ((uport->status & mask) == UPSTAT_CTS_ENABLE);
 440 }
 441
 442 /*
 443  * The following are helper functions for the low level drivers.
 444  */
 445
 446 extern void uart_handle_dcd_change(struct uart_port *uport,
 447                 unsigned int status);
 448 extern void uart_handle_cts_change(struct uart_port *uport,
 449                 unsigned int status);
 450
 451 extern void uart_insert_char(struct uart_port *port, unsigned int status,
 452                  unsigned int overrun, unsigned int ch, unsigned int flag);
 453
 454 #if defined(SUPPORT_SYSRQ) && defined(CONFIG_MAGIC_SYSRQ_SERIAL)
 455 static inline int
 456 uart_handle_sysrq_char(struct uart_port *port, unsigned int ch)
 457 {
 458         if (port->sysrq) {
 459                 if (ch && time_before(jiffies, port->sysrq)) {
 460                         handle_sysrq(ch);
 461                         port->sysrq = 0;
 462                         return 1;
 463                 }
 464                 port->sysrq = 0;
 465         }
 466         return 0;
 467 }
 468 #else
 469 #define uart_handle_sysrq_char(port,ch) ({ (void)port; 0; })
 470 #endif
 471
 472 /*
 473  * We do the SysRQ and SAK checking like this...
 474  */
 475 static inline int uart_handle_break(struct uart_port *port)
 476 {
 477         struct uart_state *state = port->state;
 478
 479         if (port->handle_break)
 480                 port->handle_break(port);
 481
 482 #ifdef SUPPORT_SYSRQ
 483         if (port->cons && port->cons->index == port->line) {
 484                 if (!port->sysrq) {
 485                         port->sysrq = jiffies + HZ*5;
 486                         return 1;
 487                 }
 488                 port->sysrq = 0;
 489         }
 490 #endif
 491         if (port->flags & UPF_SAK)
 492                 do_SAK(state->port.tty);
 493         return 0;
 494 }
 495
 496 /*
 497  *      UART_ENABLE_MS - determine if port should enable modem status irqs
 498  */
 499 #define UART_ENABLE_MS(port,cflag)      ((port)->flags & UPF_HARDPPS_CD || \
 500                                          (cflag) & CRTSCTS || \
 501                                          !((cflag) & CLOCAL))
 502
 503 #endif /* LINUX_SERIAL_CORE_H */