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TOMOYO Linux Cross Reference
Linux/include/linux/serial_core.h

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  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/gpio/consumer.h>
 14 #include <linux/interrupt.h>
 15 #include <linux/circ_buf.h>
 16 #include <linux/spinlock.h>
 17 #include <linux/sched.h>
 18 #include <linux/tty.h>
 19 #include <linux/mutex.h>
 20 #include <linux/sysrq.h>
 21 #include <uapi/linux/serial_core.h>
 22 
 23 #ifdef CONFIG_SERIAL_CORE_CONSOLE
 24 #define uart_console(port) \
 25         ((port)->cons && (port)->cons->index == (port)->line)
 26 #else
 27 #define uart_console(port)      ({ (void)port; 0; })
 28 #endif
 29 
 30 struct uart_port;
 31 struct serial_struct;
 32 struct device;
 33 
 34 /*
 35  * This structure describes all the operations that can be done on the
 36  * physical hardware.  See Documentation/driver-api/serial/driver.rst for details.
 37  */
 38 struct uart_ops {
 39         unsigned int    (*tx_empty)(struct uart_port *);
 40         void            (*set_mctrl)(struct uart_port *, unsigned int mctrl);
 41         unsigned int    (*get_mctrl)(struct uart_port *);
 42         void            (*stop_tx)(struct uart_port *);
 43         void            (*start_tx)(struct uart_port *);
 44         void            (*throttle)(struct uart_port *);
 45         void            (*unthrottle)(struct uart_port *);
 46         void            (*send_xchar)(struct uart_port *, char ch);
 47         void            (*stop_rx)(struct uart_port *);
 48         void            (*enable_ms)(struct uart_port *);
 49         void            (*break_ctl)(struct uart_port *, int ctl);
 50         int             (*startup)(struct uart_port *);
 51         void            (*shutdown)(struct uart_port *);
 52         void            (*flush_buffer)(struct uart_port *);
 53         void            (*set_termios)(struct uart_port *, struct ktermios *new,
 54                                        struct ktermios *old);
 55         void            (*set_ldisc)(struct uart_port *, struct ktermios *);
 56         void            (*pm)(struct uart_port *, unsigned int state,
 57                               unsigned int oldstate);
 58 
 59         /*
 60          * Return a string describing the type of the port
 61          */
 62         const char      *(*type)(struct uart_port *);
 63 
 64         /*
 65          * Release IO and memory resources used by the port.
 66          * This includes iounmap if necessary.
 67          */
 68         void            (*release_port)(struct uart_port *);
 69 
 70         /*
 71          * Request IO and memory resources used by the port.
 72          * This includes iomapping the port if necessary.
 73          */
 74         int             (*request_port)(struct uart_port *);
 75         void            (*config_port)(struct uart_port *, int);
 76         int             (*verify_port)(struct uart_port *, struct serial_struct *);
 77         int             (*ioctl)(struct uart_port *, unsigned int, unsigned long);
 78 #ifdef CONFIG_CONSOLE_POLL
 79         int             (*poll_init)(struct uart_port *);
 80         void            (*poll_put_char)(struct uart_port *, unsigned char);
 81         int             (*poll_get_char)(struct uart_port *);
 82 #endif
 83 };
 84 
 85 #define NO_POLL_CHAR            0x00ff0000
 86 #define UART_CONFIG_TYPE        (1 << 0)
 87 #define UART_CONFIG_IRQ         (1 << 1)
 88 
 89 struct uart_icount {
 90         __u32   cts;
 91         __u32   dsr;
 92         __u32   rng;
 93         __u32   dcd;
 94         __u32   rx;
 95         __u32   tx;
 96         __u32   frame;
 97         __u32   overrun;
 98         __u32   parity;
 99         __u32   brk;
100         __u32   buf_overrun;
101 };
102 
103 typedef unsigned int __bitwise upf_t;
104 typedef unsigned int __bitwise upstat_t;
105 
106 struct uart_port {
107         spinlock_t              lock;                   /* port lock */
108         unsigned long           iobase;                 /* in/out[bwl] */
109         unsigned char __iomem   *membase;               /* read/write[bwl] */
110         unsigned int            (*serial_in)(struct uart_port *, int);
111         void                    (*serial_out)(struct uart_port *, int, int);
112         void                    (*set_termios)(struct uart_port *,
113                                                struct ktermios *new,
114                                                struct ktermios *old);
115         void                    (*set_ldisc)(struct uart_port *,
116                                              struct ktermios *);
117         unsigned int            (*get_mctrl)(struct uart_port *);
118         void                    (*set_mctrl)(struct uart_port *, unsigned int);
119         unsigned int            (*get_divisor)(struct uart_port *,
120                                                unsigned int baud,
121                                                unsigned int *frac);
122         void                    (*set_divisor)(struct uart_port *,
123                                                unsigned int baud,
124                                                unsigned int quot,
125                                                unsigned int quot_frac);
126         int                     (*startup)(struct uart_port *port);
127         void                    (*shutdown)(struct uart_port *port);
128         void                    (*throttle)(struct uart_port *port);
129         void                    (*unthrottle)(struct uart_port *port);
130         int                     (*handle_irq)(struct uart_port *);
131         void                    (*pm)(struct uart_port *, unsigned int state,
132                                       unsigned int old);
133         void                    (*handle_break)(struct uart_port *);
134         int                     (*rs485_config)(struct uart_port *,
135                                                 struct serial_rs485 *rs485);
136         int                     (*iso7816_config)(struct uart_port *,
137                                                   struct serial_iso7816 *iso7816);
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           quirks;                 /* internal quirks */
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         /* quirks must be updated while holding port mutex */
157 #define UPQ_NO_TXEN_TEST        BIT(0)
158 
159         unsigned int            read_status_mask;       /* driver specific */
160         unsigned int            ignore_status_mask;     /* driver specific */
161         struct uart_state       *state;                 /* pointer to parent state */
162         struct uart_icount      icount;                 /* statistics */
163 
164         struct console          *cons;                  /* struct console, if any */
165         /* flags must be updated while holding port mutex */
166         upf_t                   flags;
167 
168         /*
169          * These flags must be equivalent to the flags defined in
170          * include/uapi/linux/tty_flags.h which are the userspace definitions
171          * assigned from the serial_struct flags in uart_set_info()
172          * [for bit definitions in the UPF_CHANGE_MASK]
173          *
174          * Bits [0..UPF_LAST_USER] are userspace defined/visible/changeable
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_MAGIC_MULTIPLIER    ((__force upf_t) ASYNC_MAGIC_MULTIPLIER /* 16 */ )
192 
193 #define UPF_NO_THRE_TEST        ((__force upf_t) (1 << 19))
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 #define UPSTAT_SYNC_FIFO        ((__force upstat_t) (1 << 5))
231 
232         int                     hw_stopped;             /* sw-assisted CTS flow state */
233         unsigned int            mctrl;                  /* current modem ctrl settings */
234         unsigned int            timeout;                /* character-based timeout */
235         unsigned int            type;                   /* port type */
236         const struct uart_ops   *ops;
237         unsigned int            custom_divisor;
238         unsigned int            line;                   /* port index */
239         unsigned int            minor;
240         resource_size_t         mapbase;                /* for ioremap */
241         resource_size_t         mapsize;
242         struct device           *dev;                   /* parent device */
243 
244         unsigned long           sysrq;                  /* sysrq timeout */
245         unsigned int            sysrq_ch;               /* char for sysrq */
246         unsigned char           has_sysrq;
247         unsigned char           sysrq_seq;              /* index in sysrq_toggle_seq */
248 
249         unsigned char           hub6;                   /* this should be in the 8250 driver */
250         unsigned char           suspended;
251         const char              *name;                  /* port name */
252         struct attribute_group  *attr_group;            /* port specific attributes */
253         const struct attribute_group **tty_groups;      /* all attributes (serial core use only) */
254         struct serial_rs485     rs485;
255         struct gpio_desc        *rs485_term_gpio;       /* enable RS485 bus termination */
256         struct serial_iso7816   iso7816;
257         void                    *private_data;          /* generic platform data pointer */
258 };
259 
260 static inline int serial_port_in(struct uart_port *up, int offset)
261 {
262         return up->serial_in(up, offset);
263 }
264 
265 static inline void serial_port_out(struct uart_port *up, int offset, int value)
266 {
267         up->serial_out(up, offset, value);
268 }
269 
270 /**
271  * enum uart_pm_state - power states for UARTs
272  * @UART_PM_STATE_ON: UART is powered, up and operational
273  * @UART_PM_STATE_OFF: UART is powered off
274  * @UART_PM_STATE_UNDEFINED: sentinel
275  */
276 enum uart_pm_state {
277         UART_PM_STATE_ON = 0,
278         UART_PM_STATE_OFF = 3, /* number taken from ACPI */
279         UART_PM_STATE_UNDEFINED,
280 };
281 
282 /*
283  * This is the state information which is persistent across opens.
284  */
285 struct uart_state {
286         struct tty_port         port;
287 
288         enum uart_pm_state      pm_state;
289         struct circ_buf         xmit;
290 
291         atomic_t                refcount;
292         wait_queue_head_t       remove_wait;
293         struct uart_port        *uart_port;
294 };
295 
296 #define UART_XMIT_SIZE  PAGE_SIZE
297 
298 
299 /* number of characters left in xmit buffer before we ask for more */
300 #define WAKEUP_CHARS            256
301 
302 struct module;
303 struct tty_driver;
304 
305 struct uart_driver {
306         struct module           *owner;
307         const char              *driver_name;
308         const char              *dev_name;
309         int                      major;
310         int                      minor;
311         int                      nr;
312         struct console          *cons;
313 
314         /*
315          * these are private; the low level driver should not
316          * touch these; they should be initialised to NULL
317          */
318         struct uart_state       *state;
319         struct tty_driver       *tty_driver;
320 };
321 
322 void uart_write_wakeup(struct uart_port *port);
323 
324 /*
325  * Baud rate helpers.
326  */
327 void uart_update_timeout(struct uart_port *port, unsigned int cflag,
328                          unsigned int baud);
329 unsigned int uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
330                                 struct ktermios *old, unsigned int min,
331                                 unsigned int max);
332 unsigned int uart_get_divisor(struct uart_port *port, unsigned int baud);
333 
334 /* Base timer interval for polling */
335 static inline int uart_poll_timeout(struct uart_port *port)
336 {
337         int timeout = port->timeout;
338 
339         return timeout > 6 ? (timeout / 2 - 2) : 1;
340 }
341 
342 /*
343  * Console helpers.
344  */
345 struct earlycon_device {
346         struct console *con;
347         struct uart_port port;
348         char options[16];               /* e.g., 115200n8 */
349         unsigned int baud;
350 };
351 
352 struct earlycon_id {
353         char    name[15];
354         char    name_term;      /* In case compiler didn't '\0' term name */
355         char    compatible[128];
356         int     (*setup)(struct earlycon_device *, const char *options);
357 };
358 
359 extern const struct earlycon_id *__earlycon_table[];
360 extern const struct earlycon_id *__earlycon_table_end[];
361 
362 #if defined(CONFIG_SERIAL_EARLYCON) && !defined(MODULE)
363 #define EARLYCON_USED_OR_UNUSED __used
364 #else
365 #define EARLYCON_USED_OR_UNUSED __maybe_unused
366 #endif
367 
368 #define _OF_EARLYCON_DECLARE(_name, compat, fn, unique_id)              \
369         static const struct earlycon_id unique_id                       \
370              EARLYCON_USED_OR_UNUSED __initconst                        \
371                 = { .name = __stringify(_name),                         \
372                     .compatible = compat,                               \
373                     .setup = fn  };                                     \
374         static const struct earlycon_id EARLYCON_USED_OR_UNUSED         \
375                 __section(__earlycon_table)                             \
376                 * const __PASTE(__p, unique_id) = &unique_id
377 
378 #define OF_EARLYCON_DECLARE(_name, compat, fn)                          \
379         _OF_EARLYCON_DECLARE(_name, compat, fn,                         \
380                              __UNIQUE_ID(__earlycon_##_name))
381 
382 #define EARLYCON_DECLARE(_name, fn)     OF_EARLYCON_DECLARE(_name, "", fn)
383 
384 extern int of_setup_earlycon(const struct earlycon_id *match,
385                              unsigned long node,
386                              const char *options);
387 
388 #ifdef CONFIG_SERIAL_EARLYCON
389 extern bool earlycon_acpi_spcr_enable __initdata;
390 int setup_earlycon(char *buf);
391 #else
392 static const bool earlycon_acpi_spcr_enable EARLYCON_USED_OR_UNUSED;
393 static inline int setup_earlycon(char *buf) { return 0; }
394 #endif
395 
396 struct uart_port *uart_get_console(struct uart_port *ports, int nr,
397                                    struct console *c);
398 int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
399                         char **options);
400 void uart_parse_options(const char *options, int *baud, int *parity, int *bits,
401                         int *flow);
402 int uart_set_options(struct uart_port *port, struct console *co, int baud,
403                      int parity, int bits, int flow);
404 struct tty_driver *uart_console_device(struct console *co, int *index);
405 void uart_console_write(struct uart_port *port, const char *s,
406                         unsigned int count,
407                         void (*putchar)(struct uart_port *, int));
408 
409 /*
410  * Port/driver registration/removal
411  */
412 int uart_register_driver(struct uart_driver *uart);
413 void uart_unregister_driver(struct uart_driver *uart);
414 int uart_add_one_port(struct uart_driver *reg, struct uart_port *port);
415 int uart_remove_one_port(struct uart_driver *reg, struct uart_port *port);
416 int uart_match_port(struct uart_port *port1, struct uart_port *port2);
417 
418 /*
419  * Power Management
420  */
421 int uart_suspend_port(struct uart_driver *reg, struct uart_port *port);
422 int uart_resume_port(struct uart_driver *reg, struct uart_port *port);
423 
424 #define uart_circ_empty(circ)           ((circ)->head == (circ)->tail)
425 #define uart_circ_clear(circ)           ((circ)->head = (circ)->tail = 0)
426 
427 #define uart_circ_chars_pending(circ)   \
428         (CIRC_CNT((circ)->head, (circ)->tail, UART_XMIT_SIZE))
429 
430 #define uart_circ_chars_free(circ)      \
431         (CIRC_SPACE((circ)->head, (circ)->tail, UART_XMIT_SIZE))
432 
433 static inline int uart_tx_stopped(struct uart_port *port)
434 {
435         struct tty_struct *tty = port->state->port.tty;
436         if ((tty && tty->stopped) || port->hw_stopped)
437                 return 1;
438         return 0;
439 }
440 
441 static inline bool uart_cts_enabled(struct uart_port *uport)
442 {
443         return !!(uport->status & UPSTAT_CTS_ENABLE);
444 }
445 
446 static inline bool uart_softcts_mode(struct uart_port *uport)
447 {
448         upstat_t mask = UPSTAT_CTS_ENABLE | UPSTAT_AUTOCTS;
449 
450         return ((uport->status & mask) == UPSTAT_CTS_ENABLE);
451 }
452 
453 /*
454  * The following are helper functions for the low level drivers.
455  */
456 
457 extern void uart_handle_dcd_change(struct uart_port *uport,
458                 unsigned int status);
459 extern void uart_handle_cts_change(struct uart_port *uport,
460                 unsigned int status);
461 
462 extern void uart_insert_char(struct uart_port *port, unsigned int status,
463                  unsigned int overrun, unsigned int ch, unsigned int flag);
464 
465 #ifdef CONFIG_MAGIC_SYSRQ_SERIAL
466 #define SYSRQ_TIMEOUT   (HZ * 5)
467 
468 bool uart_try_toggle_sysrq(struct uart_port *port, unsigned int ch);
469 
470 static inline int uart_handle_sysrq_char(struct uart_port *port, unsigned int ch)
471 {
472         if (!port->sysrq)
473                 return 0;
474 
475         if (ch && time_before(jiffies, port->sysrq)) {
476                 if (sysrq_mask()) {
477                         handle_sysrq(ch);
478                         port->sysrq = 0;
479                         return 1;
480                 }
481                 if (uart_try_toggle_sysrq(port, ch))
482                         return 1;
483         }
484         port->sysrq = 0;
485 
486         return 0;
487 }
488 
489 static inline int uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch)
490 {
491         if (!port->sysrq)
492                 return 0;
493 
494         if (ch && time_before(jiffies, port->sysrq)) {
495                 if (sysrq_mask()) {
496                         port->sysrq_ch = ch;
497                         port->sysrq = 0;
498                         return 1;
499                 }
500                 if (uart_try_toggle_sysrq(port, ch))
501                         return 1;
502         }
503         port->sysrq = 0;
504 
505         return 0;
506 }
507 
508 static inline void uart_unlock_and_check_sysrq(struct uart_port *port, unsigned long irqflags)
509 {
510         int sysrq_ch;
511 
512         if (!port->has_sysrq) {
513                 spin_unlock_irqrestore(&port->lock, irqflags);
514                 return;
515         }
516 
517         sysrq_ch = port->sysrq_ch;
518         port->sysrq_ch = 0;
519 
520         spin_unlock_irqrestore(&port->lock, irqflags);
521 
522         if (sysrq_ch)
523                 handle_sysrq(sysrq_ch);
524 }
525 #else   /* CONFIG_MAGIC_SYSRQ_SERIAL */
526 static inline int uart_handle_sysrq_char(struct uart_port *port, unsigned int ch)
527 {
528         return 0;
529 }
530 static inline int uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch)
531 {
532         return 0;
533 }
534 static inline void uart_unlock_and_check_sysrq(struct uart_port *port, unsigned long irqflags)
535 {
536         spin_unlock_irqrestore(&port->lock, irqflags);
537 }
538 #endif  /* CONFIG_MAGIC_SYSRQ_SERIAL */
539 
540 /*
541  * We do the SysRQ and SAK checking like this...
542  */
543 static inline int uart_handle_break(struct uart_port *port)
544 {
545         struct uart_state *state = port->state;
546 
547         if (port->handle_break)
548                 port->handle_break(port);
549 
550 #ifdef CONFIG_MAGIC_SYSRQ_SERIAL
551         if (port->has_sysrq && uart_console(port)) {
552                 if (!port->sysrq) {
553                         port->sysrq = jiffies + SYSRQ_TIMEOUT;
554                         return 1;
555                 }
556                 port->sysrq = 0;
557         }
558 #endif
559         if (port->flags & UPF_SAK)
560                 do_SAK(state->port.tty);
561         return 0;
562 }
563 
564 /*
565  *      UART_ENABLE_MS - determine if port should enable modem status irqs
566  */
567 #define UART_ENABLE_MS(port,cflag)      ((port)->flags & UPF_HARDPPS_CD || \
568                                          (cflag) & CRTSCTS || \
569                                          !((cflag) & CLOCAL))
570 
571 int uart_get_rs485_mode(struct uart_port *port);
572 #endif /* LINUX_SERIAL_CORE_H */
573 

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