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_mctrl)(struct uart_port *, unsigned int);
 127         int                     (*startup)(struct uart_port *port);
 128         void                    (*shutdown)(struct uart_port *port);
 129         void                    (*throttle)(struct uart_port *port);
 130         void                    (*unthrottle)(struct uart_port *port);
 131         int                     (*handle_irq)(struct uart_port *);
 132         void                    (*pm)(struct uart_port *, unsigned int state,
 133                                       unsigned int old);
 134         void                    (*handle_break)(struct uart_port *);
 135         int                     (*rs485_config)(struct uart_port *,
 136                                                 struct serial_rs485 *rs485);
 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           unused1;
 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)         /* 8b MMIO access */
 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
 154         unsigned int            read_status_mask;       /* driver specific */
 155         unsigned int            ignore_status_mask;     /* driver specific */
 156         struct uart_state       *state;                 /* pointer to parent state */
 157         struct uart_icount      icount;                 /* statistics */
 158
 159         struct console          *cons;                  /* struct console, if any */
 160 #if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(SUPPORT_SYSRQ)
 161         unsigned long           sysrq;                  /* sysrq timeout */
 162 #endif
 163
 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          * except bit 15 (UPF_NO_TXEN_TEST) which is masked off.
 175          * The remaining bits are serial-core specific and not modifiable by
 176          * userspace.
 177          */
 178 #define UPF_FOURPORT            ((__force upf_t) ASYNC_FOURPORT       /* 1  */ )
 179 #define UPF_SAK                 ((__force upf_t) ASYNC_SAK            /* 2  */ )
 180 #define UPF_SPD_HI              ((__force upf_t) ASYNC_SPD_HI         /* 4  */ )
 181 #define UPF_SPD_VHI             ((__force upf_t) ASYNC_SPD_VHI        /* 5  */ )
 182 #define UPF_SPD_CUST            ((__force upf_t) ASYNC_SPD_CUST   /* 0x0030 */ )
 183 #define UPF_SPD_WARP            ((__force upf_t) ASYNC_SPD_WARP   /* 0x1010 */ )
 184 #define UPF_SPD_MASK            ((__force upf_t) ASYNC_SPD_MASK   /* 0x1030 */ )
 185 #define UPF_SKIP_TEST           ((__force upf_t) ASYNC_SKIP_TEST      /* 6  */ )
 186 #define UPF_AUTO_IRQ            ((__force upf_t) ASYNC_AUTO_IRQ       /* 7  */ )
 187 #define UPF_HARDPPS_CD          ((__force upf_t) ASYNC_HARDPPS_CD     /* 11 */ )
 188 #define UPF_SPD_SHI             ((__force upf_t) ASYNC_SPD_SHI        /* 12 */ )
 189 #define UPF_LOW_LATENCY         ((__force upf_t) ASYNC_LOW_LATENCY    /* 13 */ )
 190 #define UPF_BUGGY_UART          ((__force upf_t) ASYNC_BUGGY_UART     /* 14 */ )
 191 #define UPF_NO_TXEN_TEST        ((__force upf_t) (1 << 15))
 192 #define UPF_MAGIC_MULTIPLIER    ((__force upf_t) ASYNC_MAGIC_MULTIPLIER /* 16 */ )
 193
 194 /* Port has hardware-assisted h/w flow control */
 195 #define UPF_AUTO_CTS            ((__force upf_t) (1 << 20))
 196 #define UPF_AUTO_RTS            ((__force upf_t) (1 << 21))
 197 #define UPF_HARD_FLOW           ((__force upf_t) (UPF_AUTO_CTS | UPF_AUTO_RTS))
 198 /* Port has hardware-assisted s/w flow control */
 199 #define UPF_SOFT_FLOW           ((__force upf_t) (1 << 22))
 200 #define UPF_CONS_FLOW           ((__force upf_t) (1 << 23))
 201 #define UPF_SHARE_IRQ           ((__force upf_t) (1 << 24))
 202 #define UPF_EXAR_EFR            ((__force upf_t) (1 << 25))
 203 #define UPF_BUG_THRE            ((__force upf_t) (1 << 26))
 204 /* The exact UART type is known and should not be probed.  */
 205 #define UPF_FIXED_TYPE          ((__force upf_t) (1 << 27))
 206 #define UPF_BOOT_AUTOCONF       ((__force upf_t) (1 << 28))
 207 #define UPF_FIXED_PORT          ((__force upf_t) (1 << 29))
 208 #define UPF_DEAD                ((__force upf_t) (1 << 30))
 209 #define UPF_IOREMAP             ((__force upf_t) (1 << 31))
 210
 211 #define __UPF_CHANGE_MASK       0x17fff
 212 #define UPF_CHANGE_MASK         ((__force upf_t) __UPF_CHANGE_MASK)
 213 #define UPF_USR_MASK            ((__force upf_t) (UPF_SPD_MASK|UPF_LOW_LATENCY))
 214
 215 #if __UPF_CHANGE_MASK > ASYNC_FLAGS
 216 #error Change mask not equivalent to userspace-visible bit defines
 217 #endif
 218
 219         /*
 220          * Must hold termios_rwsem, port mutex and port lock to change;
 221          * can hold any one lock to read.
 222          */
 223         upstat_t                status;
 224
 225 #define UPSTAT_CTS_ENABLE       ((__force upstat_t) (1 << 0))
 226 #define UPSTAT_DCD_ENABLE       ((__force upstat_t) (1 << 1))
 227 #define UPSTAT_AUTORTS          ((__force upstat_t) (1 << 2))
 228 #define UPSTAT_AUTOCTS          ((__force upstat_t) (1 << 3))
 229 #define UPSTAT_AUTOXOFF         ((__force upstat_t) (1 << 4))
 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         unsigned char           hub6;                   /* this should be in the 8250 driver */
 243         unsigned char           suspended;
 244         unsigned char           irq_wake;
 245         unsigned char           unused[2];
 246         struct attribute_group  *attr_group;            /* port specific attributes */
 247         const struct attribute_group **tty_groups;      /* all attributes (serial core use only) */
 248         struct serial_rs485     rs485;
 249         void                    *private_data;          /* generic platform data pointer */
 250 };
 251
 252 static inline int serial_port_in(struct uart_port *up, int offset)
 253 {
 254         return up->serial_in(up, offset);
 255 }
 256
 257 static inline void serial_port_out(struct uart_port *up, int offset, int value)
 258 {
 259         up->serial_out(up, offset, value);
 260 }
 261
 262 /**
 263  * enum uart_pm_state - power states for UARTs
 264  * @UART_PM_STATE_ON: UART is powered, up and operational
 265  * @UART_PM_STATE_OFF: UART is powered off
 266  * @UART_PM_STATE_UNDEFINED: sentinel
 267  */
 268 enum uart_pm_state {
 269         UART_PM_STATE_ON = 0,
 270         UART_PM_STATE_OFF = 3, /* number taken from ACPI */
 271         UART_PM_STATE_UNDEFINED,
 272 };
 273
 274 /*
 275  * This is the state information which is persistent across opens.
 276  */
 277 struct uart_state {
 278         struct tty_port         port;
 279
 280         enum uart_pm_state      pm_state;
 281         struct circ_buf         xmit;
 282
 283         struct uart_port        *uart_port;
 284 };
 285
 286 #define UART_XMIT_SIZE  PAGE_SIZE
 287
 288
 289 /* number of characters left in xmit buffer before we ask for more */
 290 #define WAKEUP_CHARS            256
 291
 292 struct module;
 293 struct tty_driver;
 294
 295 struct uart_driver {
 296         struct module           *owner;
 297         const char              *driver_name;
 298         const char              *dev_name;
 299         int                      major;
 300         int                      minor;
 301         int                      nr;
 302         struct console          *cons;
 303
 304         /*
 305          * these are private; the low level driver should not
 306          * touch these; they should be initialised to NULL
 307          */
 308         struct uart_state       *state;
 309         struct tty_driver       *tty_driver;
 310 };
 311
 312 void uart_write_wakeup(struct uart_port *port);
 313
 314 /*
 315  * Baud rate helpers.
 316  */
 317 void uart_update_timeout(struct uart_port *port, unsigned int cflag,
 318                          unsigned int baud);
 319 unsigned int uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
 320                                 struct ktermios *old, unsigned int min,
 321                                 unsigned int max);
 322 unsigned int uart_get_divisor(struct uart_port *port, unsigned int baud);
 323
 324 /* Base timer interval for polling */
 325 static inline int uart_poll_timeout(struct uart_port *port)
 326 {
 327         int timeout = port->timeout;
 328
 329         return timeout > 6 ? (timeout / 2 - 2) : 1;
 330 }
 331
 332 /*
 333  * Console helpers.
 334  */
 335 struct earlycon_device {
 336         struct console *con;
 337         struct uart_port port;
 338         char options[16];               /* e.g., 115200n8 */
 339         unsigned int baud;
 340 };
 341
 342 struct earlycon_id {
 343         char    name[16];
 344         int     (*setup)(struct earlycon_device *, const char *options);
 345 } __aligned(32);
 346
 347 extern int setup_earlycon(char *buf);
 348 extern int of_setup_earlycon(unsigned long addr,
 349                              int (*setup)(struct earlycon_device *, const char *));
 350
 351 #define EARLYCON_DECLARE(_name, func)                                   \
 352         static const struct earlycon_id __earlycon_##_name              \
 353                 __used __section(__earlycon_table)                      \
 354                  = { .name  = __stringify(_name),                       \
 355                      .setup = func  }
 356
 357 #define OF_EARLYCON_DECLARE(name, compat, fn)                           \
 358         _OF_DECLARE(earlycon, name, compat, fn, void *)
 359
 360 struct uart_port *uart_get_console(struct uart_port *ports, int nr,
 361                                    struct console *c);
 362 int uart_parse_earlycon(char *p, unsigned char *iotype, unsigned long *addr,
 363                         char **options);
 364 void uart_parse_options(char *options, int *baud, int *parity, int *bits,
 365                         int *flow);
 366 int uart_set_options(struct uart_port *port, struct console *co, int baud,
 367                      int parity, int bits, int flow);
 368 struct tty_driver *uart_console_device(struct console *co, int *index);
 369 void uart_console_write(struct uart_port *port, const char *s,
 370                         unsigned int count,
 371                         void (*putchar)(struct uart_port *, int));
 372
 373 /*
 374  * Port/driver registration/removal
 375  */
 376 int uart_register_driver(struct uart_driver *uart);
 377 void uart_unregister_driver(struct uart_driver *uart);
 378 int uart_add_one_port(struct uart_driver *reg, struct uart_port *port);
 379 int uart_remove_one_port(struct uart_driver *reg, struct uart_port *port);
 380 int uart_match_port(struct uart_port *port1, struct uart_port *port2);
 381
 382 /*
 383  * Power Management
 384  */
 385 int uart_suspend_port(struct uart_driver *reg, struct uart_port *port);
 386 int uart_resume_port(struct uart_driver *reg, struct uart_port *port);
 387
 388 #define uart_circ_empty(circ)           ((circ)->head == (circ)->tail)
 389 #define uart_circ_clear(circ)           ((circ)->head = (circ)->tail = 0)
 390
 391 #define uart_circ_chars_pending(circ)   \
 392         (CIRC_CNT((circ)->head, (circ)->tail, UART_XMIT_SIZE))
 393
 394 #define uart_circ_chars_free(circ)      \
 395         (CIRC_SPACE((circ)->head, (circ)->tail, UART_XMIT_SIZE))
 396
 397 static inline int uart_tx_stopped(struct uart_port *port)
 398 {
 399         struct tty_struct *tty = port->state->port.tty;
 400         if (tty->stopped || port->hw_stopped)
 401                 return 1;
 402         return 0;
 403 }
 404
 405 static inline bool uart_cts_enabled(struct uart_port *uport)
 406 {
 407         return !!(uport->status & UPSTAT_CTS_ENABLE);
 408 }
 409
 410 static inline bool uart_softcts_mode(struct uart_port *uport)
 411 {
 412         upstat_t mask = UPSTAT_CTS_ENABLE | UPSTAT_AUTOCTS;
 413
 414         return ((uport->status & mask) == UPSTAT_CTS_ENABLE);
 415 }
 416
 417 /*
 418  * The following are helper functions for the low level drivers.
 419  */
 420
 421 extern void uart_handle_dcd_change(struct uart_port *uport,
 422                 unsigned int status);
 423 extern void uart_handle_cts_change(struct uart_port *uport,
 424                 unsigned int status);
 425
 426 extern void uart_insert_char(struct uart_port *port, unsigned int status,
 427                  unsigned int overrun, unsigned int ch, unsigned int flag);
 428
 429 #ifdef SUPPORT_SYSRQ
 430 static inline int
 431 uart_handle_sysrq_char(struct uart_port *port, unsigned int ch)
 432 {
 433         if (port->sysrq) {
 434                 if (ch && time_before(jiffies, port->sysrq)) {
 435                         handle_sysrq(ch);
 436                         port->sysrq = 0;
 437                         return 1;
 438                 }
 439                 port->sysrq = 0;
 440         }
 441         return 0;
 442 }
 443 #else
 444 #define uart_handle_sysrq_char(port,ch) ({ (void)port; 0; })
 445 #endif
 446
 447 /*
 448  * We do the SysRQ and SAK checking like this...
 449  */
 450 static inline int uart_handle_break(struct uart_port *port)
 451 {
 452         struct uart_state *state = port->state;
 453
 454         if (port->handle_break)
 455                 port->handle_break(port);
 456
 457 #ifdef SUPPORT_SYSRQ
 458         if (port->cons && port->cons->index == port->line) {
 459                 if (!port->sysrq) {
 460                         port->sysrq = jiffies + HZ*5;
 461                         return 1;
 462                 }
 463                 port->sysrq = 0;
 464         }
 465 #endif
 466         if (port->flags & UPF_SAK)
 467                 do_SAK(state->port.tty);
 468         return 0;
 469 }
 470
 471 /*
 472  *      UART_ENABLE_MS - determine if port should enable modem status irqs
 473  */
 474 #define UART_ENABLE_MS(port,cflag)      ((port)->flags & UPF_HARDPPS_CD || \
 475                                          (cflag) & CRTSCTS || \
 476                                          !((cflag) & CLOCAL))
 477
 478 #endif /* LINUX_SERIAL_CORE_H */