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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/interrupt.h>
14#include <linux/circ_buf.h>
15#include <linux/spinlock.h>
16#include <linux/sched.h>
17#include <linux/tty.h>
18#include <linux/mutex.h>
19#include <linux/sysrq.h>
20#include <uapi/linux/serial_core.h>
21
22#ifdef CONFIG_SERIAL_CORE_CONSOLE
23#define uart_console(port) \
24 ((port)->cons && (port)->cons->index == (port)->line)
25#else
26#define uart_console(port) ({ (void)port; 0; })
27#endif
28
29struct uart_port;
30struct serial_struct;
31struct device;
32
33/*
34 * This structure describes all the operations that can be done on the
35 * physical hardware. See Documentation/driver-api/serial/driver.rst for details.
36 */
37struct uart_ops {
38 unsigned int (*tx_empty)(struct uart_port *);
39 void (*set_mctrl)(struct uart_port *, unsigned int mctrl);
40 unsigned int (*get_mctrl)(struct uart_port *);
41 void (*stop_tx)(struct uart_port *);
42 void (*start_tx)(struct uart_port *);
43 void (*throttle)(struct uart_port *);
44 void (*unthrottle)(struct uart_port *);
45 void (*send_xchar)(struct uart_port *, char ch);
46 void (*stop_rx)(struct uart_port *);
47 void (*enable_ms)(struct uart_port *);
48 void (*break_ctl)(struct uart_port *, int ctl);
49 int (*startup)(struct uart_port *);
50 void (*shutdown)(struct uart_port *);
51 void (*flush_buffer)(struct uart_port *);
52 void (*set_termios)(struct uart_port *, struct ktermios *new,
53 struct ktermios *old);
54 void (*set_ldisc)(struct uart_port *, struct ktermios *);
55 void (*pm)(struct uart_port *, unsigned int state,
56 unsigned int oldstate);
57
58 /*
59 * Return a string describing the type of the port
60 */
61 const char *(*type)(struct uart_port *);
62
63 /*
64 * Release IO and memory resources used by the port.
65 * This includes iounmap if necessary.
66 */
67 void (*release_port)(struct uart_port *);
68
69 /*
70 * Request IO and memory resources used by the port.
71 * This includes iomapping the port if necessary.
72 */
73 int (*request_port)(struct uart_port *);
74 void (*config_port)(struct uart_port *, int);
75 int (*verify_port)(struct uart_port *, struct serial_struct *);
76 int (*ioctl)(struct uart_port *, unsigned int, unsigned long);
77#ifdef CONFIG_CONSOLE_POLL
78 int (*poll_init)(struct uart_port *);
79 void (*poll_put_char)(struct uart_port *, unsigned char);
80 int (*poll_get_char)(struct uart_port *);
81#endif
82};
83
84#define NO_POLL_CHAR 0x00ff0000
85#define UART_CONFIG_TYPE (1 << 0)
86#define UART_CONFIG_IRQ (1 << 1)
87
88struct uart_icount {
89 __u32 cts;
90 __u32 dsr;
91 __u32 rng;
92 __u32 dcd;
93 __u32 rx;
94 __u32 tx;
95 __u32 frame;
96 __u32 overrun;
97 __u32 parity;
98 __u32 brk;
99 __u32 buf_overrun;
100};
101
102typedef unsigned int __bitwise upf_t;
103typedef unsigned int __bitwise upstat_t;
104
105struct uart_port {
106 spinlock_t lock; /* port lock */
107 unsigned long iobase; /* in/out[bwl] */
108 unsigned char __iomem *membase; /* read/write[bwl] */
109 unsigned int (*serial_in)(struct uart_port *, int);
110 void (*serial_out)(struct uart_port *, int, int);
111 void (*set_termios)(struct uart_port *,
112 struct ktermios *new,
113 struct ktermios *old);
114 void (*set_ldisc)(struct uart_port *,
115 struct ktermios *);
116 unsigned int (*get_mctrl)(struct uart_port *);
117 void (*set_mctrl)(struct uart_port *, unsigned int);
118 unsigned int (*get_divisor)(struct uart_port *,
119 unsigned int baud,
120 unsigned int *frac);
121 void (*set_divisor)(struct uart_port *,
122 unsigned int baud,
123 unsigned int quot,
124 unsigned int quot_frac);
125 int (*startup)(struct uart_port *port);
126 void (*shutdown)(struct uart_port *port);
127 void (*throttle)(struct uart_port *port);
128 void (*unthrottle)(struct uart_port *port);
129 int (*handle_irq)(struct uart_port *);
130 void (*pm)(struct uart_port *, unsigned int state,
131 unsigned int old);
132 void (*handle_break)(struct uart_port *);
133 int (*rs485_config)(struct uart_port *,
134 struct serial_rs485 *rs485);
135 int (*iso7816_config)(struct uart_port *,
136 struct serial_iso7816 *iso7816);
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 quirks; /* internal quirks */
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) /* driver-specific */
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#define UPIO_MEM16 (SERIAL_IO_MEM16) /* 16b little endian */
154
155 /* quirks must be updated while holding port mutex */
156#define UPQ_NO_TXEN_TEST BIT(0)
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 /* 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 * The remaining bits are serial-core specific and not modifiable by
175 * userspace.
176 */
177#define UPF_FOURPORT ((__force upf_t) ASYNC_FOURPORT /* 1 */ )
178#define UPF_SAK ((__force upf_t) ASYNC_SAK /* 2 */ )
179#define UPF_SPD_HI ((__force upf_t) ASYNC_SPD_HI /* 4 */ )
180#define UPF_SPD_VHI ((__force upf_t) ASYNC_SPD_VHI /* 5 */ )
181#define UPF_SPD_CUST ((__force upf_t) ASYNC_SPD_CUST /* 0x0030 */ )
182#define UPF_SPD_WARP ((__force upf_t) ASYNC_SPD_WARP /* 0x1010 */ )
183#define UPF_SPD_MASK ((__force upf_t) ASYNC_SPD_MASK /* 0x1030 */ )
184#define UPF_SKIP_TEST ((__force upf_t) ASYNC_SKIP_TEST /* 6 */ )
185#define UPF_AUTO_IRQ ((__force upf_t) ASYNC_AUTO_IRQ /* 7 */ )
186#define UPF_HARDPPS_CD ((__force upf_t) ASYNC_HARDPPS_CD /* 11 */ )
187#define UPF_SPD_SHI ((__force upf_t) ASYNC_SPD_SHI /* 12 */ )
188#define UPF_LOW_LATENCY ((__force upf_t) ASYNC_LOW_LATENCY /* 13 */ )
189#define UPF_BUGGY_UART ((__force upf_t) ASYNC_BUGGY_UART /* 14 */ )
190#define UPF_MAGIC_MULTIPLIER ((__force upf_t) ASYNC_MAGIC_MULTIPLIER /* 16 */ )
191
192#define UPF_NO_THRE_TEST ((__force upf_t) (1 << 19))
193/* Port has hardware-assisted h/w flow control */
194#define UPF_AUTO_CTS ((__force upf_t) (1 << 20))
195#define UPF_AUTO_RTS ((__force upf_t) (1 << 21))
196#define UPF_HARD_FLOW ((__force upf_t) (UPF_AUTO_CTS | UPF_AUTO_RTS))
197/* Port has hardware-assisted s/w flow control */
198#define UPF_SOFT_FLOW ((__force upf_t) (1 << 22))
199#define UPF_CONS_FLOW ((__force upf_t) (1 << 23))
200#define UPF_SHARE_IRQ ((__force upf_t) (1 << 24))
201#define UPF_EXAR_EFR ((__force upf_t) (1 << 25))
202#define UPF_BUG_THRE ((__force upf_t) (1 << 26))
203/* The exact UART type is known and should not be probed. */
204#define UPF_FIXED_TYPE ((__force upf_t) (1 << 27))
205#define UPF_BOOT_AUTOCONF ((__force upf_t) (1 << 28))
206#define UPF_FIXED_PORT ((__force upf_t) (1 << 29))
207#define UPF_DEAD ((__force upf_t) (1 << 30))
208#define UPF_IOREMAP ((__force upf_t) (1 << 31))
209
210#define __UPF_CHANGE_MASK 0x17fff
211#define UPF_CHANGE_MASK ((__force upf_t) __UPF_CHANGE_MASK)
212#define UPF_USR_MASK ((__force upf_t) (UPF_SPD_MASK|UPF_LOW_LATENCY))
213
214#if __UPF_CHANGE_MASK > ASYNC_FLAGS
215#error Change mask not equivalent to userspace-visible bit defines
216#endif
217
218 /*
219 * Must hold termios_rwsem, port mutex and port lock to change;
220 * can hold any one lock to read.
221 */
222 upstat_t status;
223
224#define UPSTAT_CTS_ENABLE ((__force upstat_t) (1 << 0))
225#define UPSTAT_DCD_ENABLE ((__force upstat_t) (1 << 1))
226#define UPSTAT_AUTORTS ((__force upstat_t) (1 << 2))
227#define UPSTAT_AUTOCTS ((__force upstat_t) (1 << 3))
228#define UPSTAT_AUTOXOFF ((__force upstat_t) (1 << 4))
229#define UPSTAT_SYNC_FIFO ((__force upstat_t) (1 << 5))
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
243 unsigned long sysrq; /* sysrq timeout */
244 unsigned int sysrq_ch; /* char for sysrq */
245 unsigned char has_sysrq;
246 unsigned char sysrq_seq; /* index in sysrq_toggle_seq */
247
248 unsigned char hub6; /* this should be in the 8250 driver */
249 unsigned char suspended;
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 struct serial_iso7816 iso7816;
255 void *private_data; /* generic platform data pointer */
256};
257
258static inline int serial_port_in(struct uart_port *up, int offset)
259{
260 return up->serial_in(up, offset);
261}
262
263static inline void serial_port_out(struct uart_port *up, int offset, int value)
264{
265 up->serial_out(up, offset, value);
266}
267
268/**
269 * enum uart_pm_state - power states for UARTs
270 * @UART_PM_STATE_ON: UART is powered, up and operational
271 * @UART_PM_STATE_OFF: UART is powered off
272 * @UART_PM_STATE_UNDEFINED: sentinel
273 */
274enum uart_pm_state {
275 UART_PM_STATE_ON = 0,
276 UART_PM_STATE_OFF = 3, /* number taken from ACPI */
277 UART_PM_STATE_UNDEFINED,
278};
279
280/*
281 * This is the state information which is persistent across opens.
282 */
283struct uart_state {
284 struct tty_port port;
285
286 enum uart_pm_state pm_state;
287 struct circ_buf xmit;
288
289 atomic_t refcount;
290 wait_queue_head_t remove_wait;
291 struct uart_port *uart_port;
292};
293
294#define UART_XMIT_SIZE PAGE_SIZE
295
296
297/* number of characters left in xmit buffer before we ask for more */
298#define WAKEUP_CHARS 256
299
300struct module;
301struct tty_driver;
302
303struct uart_driver {
304 struct module *owner;
305 const char *driver_name;
306 const char *dev_name;
307 int major;
308 int minor;
309 int nr;
310 struct console *cons;
311
312 /*
313 * these are private; the low level driver should not
314 * touch these; they should be initialised to NULL
315 */
316 struct uart_state *state;
317 struct tty_driver *tty_driver;
318};
319
320void uart_write_wakeup(struct uart_port *port);
321
322/*
323 * Baud rate helpers.
324 */
325void uart_update_timeout(struct uart_port *port, unsigned int cflag,
326 unsigned int baud);
327unsigned int uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
328 struct ktermios *old, unsigned int min,
329 unsigned int max);
330unsigned int uart_get_divisor(struct uart_port *port, unsigned int baud);
331
332/* Base timer interval for polling */
333static inline int uart_poll_timeout(struct uart_port *port)
334{
335 int timeout = port->timeout;
336
337 return timeout > 6 ? (timeout / 2 - 2) : 1;
338}
339
340/*
341 * Console helpers.
342 */
343struct earlycon_device {
344 struct console *con;
345 struct uart_port port;
346 char options[16]; /* e.g., 115200n8 */
347 unsigned int baud;
348};
349
350struct earlycon_id {
351 char name[15];
352 char name_term; /* In case compiler didn't '\0' term name */
353 char compatible[128];
354 int (*setup)(struct earlycon_device *, const char *options);
355};
356
357extern const struct earlycon_id *__earlycon_table[];
358extern const struct earlycon_id *__earlycon_table_end[];
359
360#if defined(CONFIG_SERIAL_EARLYCON) && !defined(MODULE)
361#define EARLYCON_USED_OR_UNUSED __used
362#else
363#define EARLYCON_USED_OR_UNUSED __maybe_unused
364#endif
365
366#define _OF_EARLYCON_DECLARE(_name, compat, fn, unique_id) \
367 static const struct earlycon_id unique_id \
368 EARLYCON_USED_OR_UNUSED __initconst \
369 = { .name = __stringify(_name), \
370 .compatible = compat, \
371 .setup = fn }; \
372 static const struct earlycon_id EARLYCON_USED_OR_UNUSED \
373 __section(__earlycon_table) \
374 * const __PASTE(__p, unique_id) = &unique_id
375
376#define OF_EARLYCON_DECLARE(_name, compat, fn) \
377 _OF_EARLYCON_DECLARE(_name, compat, fn, \
378 __UNIQUE_ID(__earlycon_##_name))
379
380#define EARLYCON_DECLARE(_name, fn) OF_EARLYCON_DECLARE(_name, "", fn)
381
382extern int of_setup_earlycon(const struct earlycon_id *match,
383 unsigned long node,
384 const char *options);
385
386#ifdef CONFIG_SERIAL_EARLYCON
387extern bool earlycon_acpi_spcr_enable __initdata;
388int setup_earlycon(char *buf);
389#else
390static const bool earlycon_acpi_spcr_enable EARLYCON_USED_OR_UNUSED;
391static inline int setup_earlycon(char *buf) { return 0; }
392#endif
393
394struct uart_port *uart_get_console(struct uart_port *ports, int nr,
395 struct console *c);
396int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
397 char **options);
398void uart_parse_options(const char *options, int *baud, int *parity, int *bits,
399 int *flow);
400int uart_set_options(struct uart_port *port, struct console *co, int baud,
401 int parity, int bits, int flow);
402struct tty_driver *uart_console_device(struct console *co, int *index);
403void uart_console_write(struct uart_port *port, const char *s,
404 unsigned int count,
405 void (*putchar)(struct uart_port *, int));
406
407/*
408 * Port/driver registration/removal
409 */
410int uart_register_driver(struct uart_driver *uart);
411void uart_unregister_driver(struct uart_driver *uart);
412int uart_add_one_port(struct uart_driver *reg, struct uart_port *port);
413int uart_remove_one_port(struct uart_driver *reg, struct uart_port *port);
414int uart_match_port(struct uart_port *port1, struct uart_port *port2);
415
416/*
417 * Power Management
418 */
419int uart_suspend_port(struct uart_driver *reg, struct uart_port *port);
420int uart_resume_port(struct uart_driver *reg, struct uart_port *port);
421
422#define uart_circ_empty(circ) ((circ)->head == (circ)->tail)
423#define uart_circ_clear(circ) ((circ)->head = (circ)->tail = 0)
424
425#define uart_circ_chars_pending(circ) \
426 (CIRC_CNT((circ)->head, (circ)->tail, UART_XMIT_SIZE))
427
428#define uart_circ_chars_free(circ) \
429 (CIRC_SPACE((circ)->head, (circ)->tail, UART_XMIT_SIZE))
430
431static inline int uart_tx_stopped(struct uart_port *port)
432{
433 struct tty_struct *tty = port->state->port.tty;
434 if ((tty && tty->stopped) || port->hw_stopped)
435 return 1;
436 return 0;
437}
438
439static inline bool uart_cts_enabled(struct uart_port *uport)
440{
441 return !!(uport->status & UPSTAT_CTS_ENABLE);
442}
443
444static inline bool uart_softcts_mode(struct uart_port *uport)
445{
446 upstat_t mask = UPSTAT_CTS_ENABLE | UPSTAT_AUTOCTS;
447
448 return ((uport->status & mask) == UPSTAT_CTS_ENABLE);
449}
450
451/*
452 * The following are helper functions for the low level drivers.
453 */
454
455extern void uart_handle_dcd_change(struct uart_port *uport,
456 unsigned int status);
457extern void uart_handle_cts_change(struct uart_port *uport,
458 unsigned int status);
459
460extern void uart_insert_char(struct uart_port *port, unsigned int status,
461 unsigned int overrun, unsigned int ch, unsigned int flag);
462
463extern int uart_handle_sysrq_char(struct uart_port *port, unsigned int ch);
464extern int uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch);
465extern void uart_unlock_and_check_sysrq(struct uart_port *port, unsigned long flags);
466extern int uart_handle_break(struct uart_port *port);
467
468/*
469 * UART_ENABLE_MS - determine if port should enable modem status irqs
470 */
471#define UART_ENABLE_MS(port,cflag) ((port)->flags & UPF_HARDPPS_CD || \
472 (cflag) & CRTSCTS || \
473 !((cflag) & CLOCAL))
474
475void uart_get_rs485_mode(struct device *dev, struct serial_rs485 *rs485conf);
476#endif /* LINUX_SERIAL_CORE_H */