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         unsigned int            (*get_mctrl)(struct uart_port *);
 127         void                    (*set_mctrl)(struct uart_port *, unsigned int);
 128         int                     (*startup)(struct uart_port *port);
 129         void                    (*shutdown)(struct uart_port *port);
 130         void                    (*throttle)(struct uart_port *port);
 131         void                    (*unthrottle)(struct uart_port *port);
 132         int                     (*handle_irq)(struct uart_port *);
 133         void                    (*pm)(struct uart_port *, unsigned int state,
 134                                       unsigned int old);
 135         void                    (*handle_break)(struct uart_port *);
 136         int                     (*rs485_config)(struct uart_port *,
 137                                                 struct serial_rs485 *rs485);
 138         unsigned int            irq;                    /* irq number */
 139         unsigned long           irqflags;               /* irq flags  */
 140         unsigned int            uartclk;                /* base uart clock */
 141         unsigned int            fifosize;               /* tx fifo size */
 142         unsigned char           x_char;                 /* xon/xoff char */
 143         unsigned char           regshift;               /* reg offset shift */
 144         unsigned char           iotype;                 /* io access style */
 145         unsigned char           unused1;
 146
 147 #define UPIO_PORT               (SERIAL_IO_PORT)        /* 8b I/O port access */
 148 #define UPIO_HUB6               (SERIAL_IO_HUB6)        /* Hub6 ISA card */
 149 #define UPIO_MEM                (SERIAL_IO_MEM)         /* driver-specific */
 150 #define UPIO_MEM32              (SERIAL_IO_MEM32)       /* 32b little endian */
 151 #define UPIO_AU                 (SERIAL_IO_AU)          /* Au1x00 and RT288x type IO */
 152 #define UPIO_TSI                (SERIAL_IO_TSI)         /* Tsi108/109 type IO */
 153 #define UPIO_MEM32BE            (SERIAL_IO_MEM32BE)     /* 32b big endian */
 154 #define UPIO_MEM16              (SERIAL_IO_MEM16)       /* 16b little endian */
 155
 156         unsigned int            read_status_mask;       /* driver specific */
 157         unsigned int            ignore_status_mask;     /* driver specific */
 158         struct uart_state       *state;                 /* pointer to parent state */
 159         struct uart_icount      icount;                 /* statistics */
 160
 161         struct console          *cons;                  /* struct console, if any */
 162 #if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(SUPPORT_SYSRQ)
 163         unsigned long           sysrq;                  /* sysrq timeout */
 164 #endif
 165
 166         /* flags must be updated while holding port mutex */
 167         upf_t                   flags;
 168
 169         /*
 170          * These flags must be equivalent to the flags defined in
 171          * include/uapi/linux/tty_flags.h which are the userspace definitions
 172          * assigned from the serial_struct flags in uart_set_info()
 173          * [for bit definitions in the UPF_CHANGE_MASK]
 174          *
 175          * Bits [0..UPF_LAST_USER] are userspace defined/visible/changeable
 176          * except bit 15 (UPF_NO_TXEN_TEST) which is masked off.
 177          * The remaining bits are serial-core specific and not modifiable by
 178          * userspace.
 179          */
 180 #define UPF_FOURPORT            ((__force upf_t) ASYNC_FOURPORT       /* 1  */ )
 181 #define UPF_SAK                 ((__force upf_t) ASYNC_SAK            /* 2  */ )
 182 #define UPF_SPD_HI              ((__force upf_t) ASYNC_SPD_HI         /* 4  */ )
 183 #define UPF_SPD_VHI             ((__force upf_t) ASYNC_SPD_VHI        /* 5  */ )
 184 #define UPF_SPD_CUST            ((__force upf_t) ASYNC_SPD_CUST   /* 0x0030 */ )
 185 #define UPF_SPD_WARP            ((__force upf_t) ASYNC_SPD_WARP   /* 0x1010 */ )
 186 #define UPF_SPD_MASK            ((__force upf_t) ASYNC_SPD_MASK   /* 0x1030 */ )
 187 #define UPF_SKIP_TEST           ((__force upf_t) ASYNC_SKIP_TEST      /* 6  */ )
 188 #define UPF_AUTO_IRQ            ((__force upf_t) ASYNC_AUTO_IRQ       /* 7  */ )
 189 #define UPF_HARDPPS_CD          ((__force upf_t) ASYNC_HARDPPS_CD     /* 11 */ )
 190 #define UPF_SPD_SHI             ((__force upf_t) ASYNC_SPD_SHI        /* 12 */ )
 191 #define UPF_LOW_LATENCY         ((__force upf_t) ASYNC_LOW_LATENCY    /* 13 */ )
 192 #define UPF_BUGGY_UART          ((__force upf_t) ASYNC_BUGGY_UART     /* 14 */ )
 193 #define UPF_NO_TXEN_TEST        ((__force upf_t) (1 << 15))
 194 #define UPF_MAGIC_MULTIPLIER    ((__force upf_t) ASYNC_MAGIC_MULTIPLIER /* 16 */ )
 195
 196 /* Port has hardware-assisted h/w flow control */
 197 #define UPF_AUTO_CTS            ((__force upf_t) (1 << 20))
 198 #define UPF_AUTO_RTS            ((__force upf_t) (1 << 21))
 199 #define UPF_HARD_FLOW           ((__force upf_t) (UPF_AUTO_CTS | UPF_AUTO_RTS))
 200 /* Port has hardware-assisted s/w flow control */
 201 #define UPF_SOFT_FLOW           ((__force upf_t) (1 << 22))
 202 #define UPF_CONS_FLOW           ((__force upf_t) (1 << 23))
 203 #define UPF_SHARE_IRQ           ((__force upf_t) (1 << 24))
 204 #define UPF_EXAR_EFR            ((__force upf_t) (1 << 25))
 205 #define UPF_BUG_THRE            ((__force upf_t) (1 << 26))
 206 /* The exact UART type is known and should not be probed.  */
 207 #define UPF_FIXED_TYPE          ((__force upf_t) (1 << 27))
 208 #define UPF_BOOT_AUTOCONF       ((__force upf_t) (1 << 28))
 209 #define UPF_FIXED_PORT          ((__force upf_t) (1 << 29))
 210 #define UPF_DEAD                ((__force upf_t) (1 << 30))
 211 #define UPF_IOREMAP             ((__force upf_t) (1 << 31))
 212
 213 #define __UPF_CHANGE_MASK       0x17fff
 214 #define UPF_CHANGE_MASK         ((__force upf_t) __UPF_CHANGE_MASK)
 215 #define UPF_USR_MASK            ((__force upf_t) (UPF_SPD_MASK|UPF_LOW_LATENCY))
 216
 217 #if __UPF_CHANGE_MASK > ASYNC_FLAGS
 218 #error Change mask not equivalent to userspace-visible bit defines
 219 #endif
 220
 221         /*
 222          * Must hold termios_rwsem, port mutex and port lock to change;
 223          * can hold any one lock to read.
 224          */
 225         upstat_t                status;
 226
 227 #define UPSTAT_CTS_ENABLE       ((__force upstat_t) (1 << 0))
 228 #define UPSTAT_DCD_ENABLE       ((__force upstat_t) (1 << 1))
 229 #define UPSTAT_AUTORTS          ((__force upstat_t) (1 << 2))
 230 #define UPSTAT_AUTOCTS          ((__force upstat_t) (1 << 3))
 231 #define UPSTAT_AUTOXOFF         ((__force upstat_t) (1 << 4))
 232
 233         int                     hw_stopped;             /* sw-assisted CTS flow state */
 234         unsigned int            mctrl;                  /* current modem ctrl settings */
 235         unsigned int            timeout;                /* character-based timeout */
 236         unsigned int            type;                   /* port type */
 237         const struct uart_ops   *ops;
 238         unsigned int            custom_divisor;
 239         unsigned int            line;                   /* port index */
 240         unsigned int            minor;
 241         resource_size_t         mapbase;                /* for ioremap */
 242         resource_size_t         mapsize;
 243         struct device           *dev;                   /* parent device */
 244         unsigned char           hub6;                   /* this should be in the 8250 driver */
 245         unsigned char           suspended;
 246         unsigned char           irq_wake;
 247         unsigned char           unused[2];
 248         struct attribute_group  *attr_group;            /* port specific attributes */
 249         const struct attribute_group **tty_groups;      /* all attributes (serial core use only) */
 250         struct serial_rs485     rs485;
 251         void                    *private_data;          /* generic platform data pointer */
 252 };
 253
 254 static inline int serial_port_in(struct uart_port *up, int offset)
 255 {
 256         return up->serial_in(up, offset);
 257 }
 258
 259 static inline void serial_port_out(struct uart_port *up, int offset, int value)
 260 {
 261         up->serial_out(up, offset, value);
 262 }
 263
 264 /**
 265  * enum uart_pm_state - power states for UARTs
 266  * @UART_PM_STATE_ON: UART is powered, up and operational
 267  * @UART_PM_STATE_OFF: UART is powered off
 268  * @UART_PM_STATE_UNDEFINED: sentinel
 269  */
 270 enum uart_pm_state {
 271         UART_PM_STATE_ON = 0,
 272         UART_PM_STATE_OFF = 3, /* number taken from ACPI */
 273         UART_PM_STATE_UNDEFINED,
 274 };
 275
 276 /*
 277  * This is the state information which is persistent across opens.
 278  */
 279 struct uart_state {
 280         struct tty_port         port;
 281
 282         enum uart_pm_state      pm_state;
 283         struct circ_buf         xmit;
 284
 285         atomic_t                refcount;
 286         wait_queue_head_t       remove_wait;
 287         struct uart_port        *uart_port;
 288 };
 289
 290 #define UART_XMIT_SIZE  PAGE_SIZE
 291
 292
 293 /* number of characters left in xmit buffer before we ask for more */
 294 #define WAKEUP_CHARS            256
 295
 296 struct module;
 297 struct tty_driver;
 298
 299 struct uart_driver {
 300         struct module           *owner;
 301         const char              *driver_name;
 302         const char              *dev_name;
 303         int                      major;
 304         int                      minor;
 305         int                      nr;
 306         struct console          *cons;
 307
 308         /*
 309          * these are private; the low level driver should not
 310          * touch these; they should be initialised to NULL
 311          */
 312         struct uart_state       *state;
 313         struct tty_driver       *tty_driver;
 314 };
 315
 316 void uart_write_wakeup(struct uart_port *port);
 317
 318 /*
 319  * Baud rate helpers.
 320  */
 321 void uart_update_timeout(struct uart_port *port, unsigned int cflag,
 322                          unsigned int baud);
 323 unsigned int uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
 324                                 struct ktermios *old, unsigned int min,
 325                                 unsigned int max);
 326 unsigned int uart_get_divisor(struct uart_port *port, unsigned int baud);
 327
 328 /* Base timer interval for polling */
 329 static inline int uart_poll_timeout(struct uart_port *port)
 330 {
 331         int timeout = port->timeout;
 332
 333         return timeout > 6 ? (timeout / 2 - 2) : 1;
 334 }
 335
 336 /*
 337  * Console helpers.
 338  */
 339 struct earlycon_device {
 340         struct console *con;
 341         struct uart_port port;
 342         char options[16];               /* e.g., 115200n8 */
 343         unsigned int baud;
 344 };
 345
 346 struct earlycon_id {
 347         char    name[16];
 348         char    compatible[128];
 349         int     (*setup)(struct earlycon_device *, const char *options);
 350 } __aligned(32);
 351
 352 extern const struct earlycon_id __earlycon_table[];
 353 extern const struct earlycon_id __earlycon_table_end[];
 354
 355 #if defined(CONFIG_SERIAL_EARLYCON) && !defined(MODULE)
 356 #define EARLYCON_USED_OR_UNUSED __used
 357 #else
 358 #define EARLYCON_USED_OR_UNUSED __maybe_unused
 359 #endif
 360
 361 #define OF_EARLYCON_DECLARE(_name, compat, fn)                          \
 362         static const struct earlycon_id __UNIQUE_ID(__earlycon_##_name) \
 363              EARLYCON_USED_OR_UNUSED __section(__earlycon_table)        \
 364                 = { .name = __stringify(_name),                         \
 365                     .compatible = compat,                               \
 366                     .setup = fn  }
 367
 368 #define EARLYCON_DECLARE(_name, fn)     OF_EARLYCON_DECLARE(_name, "", fn)
 369
 370 extern int setup_earlycon(char *buf);
 371 extern int of_setup_earlycon(const struct earlycon_id *match,
 372                              unsigned long node,
 373                              const char *options);
 374
 375 struct uart_port *uart_get_console(struct uart_port *ports, int nr,
 376                                    struct console *c);
 377 int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
 378                         char **options);
 379 void uart_parse_options(char *options, int *baud, int *parity, int *bits,
 380                         int *flow);
 381 int uart_set_options(struct uart_port *port, struct console *co, int baud,
 382                      int parity, int bits, int flow);
 383 struct tty_driver *uart_console_device(struct console *co, int *index);
 384 void uart_console_write(struct uart_port *port, const char *s,
 385                         unsigned int count,
 386                         void (*putchar)(struct uart_port *, int));
 387
 388 /*
 389  * Port/driver registration/removal
 390  */
 391 int uart_register_driver(struct uart_driver *uart);
 392 void uart_unregister_driver(struct uart_driver *uart);
 393 int uart_add_one_port(struct uart_driver *reg, struct uart_port *port);
 394 int uart_remove_one_port(struct uart_driver *reg, struct uart_port *port);
 395 int uart_match_port(struct uart_port *port1, struct uart_port *port2);
 396
 397 /*
 398  * Power Management
 399  */
 400 int uart_suspend_port(struct uart_driver *reg, struct uart_port *port);
 401 int uart_resume_port(struct uart_driver *reg, struct uart_port *port);
 402
 403 #define uart_circ_empty(circ)           ((circ)->head == (circ)->tail)
 404 #define uart_circ_clear(circ)           ((circ)->head = (circ)->tail = 0)
 405
 406 #define uart_circ_chars_pending(circ)   \
 407         (CIRC_CNT((circ)->head, (circ)->tail, UART_XMIT_SIZE))
 408
 409 #define uart_circ_chars_free(circ)      \
 410         (CIRC_SPACE((circ)->head, (circ)->tail, UART_XMIT_SIZE))
 411
 412 static inline int uart_tx_stopped(struct uart_port *port)
 413 {
 414         struct tty_struct *tty = port->state->port.tty;
 415         if (tty->stopped || port->hw_stopped)
 416                 return 1;
 417         return 0;
 418 }
 419
 420 static inline bool uart_cts_enabled(struct uart_port *uport)
 421 {
 422         return !!(uport->status & UPSTAT_CTS_ENABLE);
 423 }
 424
 425 static inline bool uart_softcts_mode(struct uart_port *uport)
 426 {
 427         upstat_t mask = UPSTAT_CTS_ENABLE | UPSTAT_AUTOCTS;
 428
 429         return ((uport->status & mask) == UPSTAT_CTS_ENABLE);
 430 }
 431
 432 /*
 433  * The following are helper functions for the low level drivers.
 434  */
 435
 436 extern void uart_handle_dcd_change(struct uart_port *uport,
 437                 unsigned int status);
 438 extern void uart_handle_cts_change(struct uart_port *uport,
 439                 unsigned int status);
 440
 441 extern void uart_insert_char(struct uart_port *port, unsigned int status,
 442                  unsigned int overrun, unsigned int ch, unsigned int flag);
 443
 444 #ifdef SUPPORT_SYSRQ
 445 static inline int
 446 uart_handle_sysrq_char(struct uart_port *port, unsigned int ch)
 447 {
 448         if (port->sysrq) {
 449                 if (ch && time_before(jiffies, port->sysrq)) {
 450                         handle_sysrq(ch);
 451                         port->sysrq = 0;
 452                         return 1;
 453                 }
 454                 port->sysrq = 0;
 455         }
 456         return 0;
 457 }
 458 #else
 459 #define uart_handle_sysrq_char(port,ch) ({ (void)port; 0; })
 460 #endif
 461
 462 /*
 463  * We do the SysRQ and SAK checking like this...
 464  */
 465 static inline int uart_handle_break(struct uart_port *port)
 466 {
 467         struct uart_state *state = port->state;
 468
 469         if (port->handle_break)
 470                 port->handle_break(port);
 471
 472 #ifdef SUPPORT_SYSRQ
 473         if (port->cons && port->cons->index == port->line) {
 474                 if (!port->sysrq) {
 475                         port->sysrq = jiffies + HZ*5;
 476                         return 1;
 477                 }
 478                 port->sysrq = 0;
 479         }
 480 #endif
 481         if (port->flags & UPF_SAK)
 482                 do_SAK(state->port.tty);
 483         return 0;
 484 }
 485
 486 /*
 487  *      UART_ENABLE_MS - determine if port should enable modem status irqs
 488  */
 489 #define UART_ENABLE_MS(port,cflag)      ((port)->flags & UPF_HARDPPS_CD || \
 490                                          (cflag) & CRTSCTS || \
 491                                          !((cflag) & CLOCAL))
 492
 493 #endif /* LINUX_SERIAL_CORE_H */