1 // SPDX-License-Identifier: GPL-2.0+
3 * Driver core for serial ports
5 * Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
7 * Copyright 1999 ARM Limited
8 * Copyright (C) 2000-2001 Deep Blue Solutions Ltd.
10 #include <linux/module.h>
11 #include <linux/tty.h>
12 #include <linux/tty_flip.h>
13 #include <linux/slab.h>
14 #include <linux/sched/signal.h>
15 #include <linux/init.h>
16 #include <linux/console.h>
17 #include <linux/gpio/consumer.h>
19 #include <linux/proc_fs.h>
20 #include <linux/seq_file.h>
21 #include <linux/device.h>
22 #include <linux/serial.h> /* for serial_state and serial_icounter_struct */
23 #include <linux/serial_core.h>
24 #include <linux/sysrq.h>
25 #include <linux/delay.h>
26 #include <linux/mutex.h>
27 #include <linux/security.h>
29 #include <linux/irq.h>
30 #include <linux/uaccess.h>
33 * This is used to lock changes in serial line configuration.
35 static DEFINE_MUTEX(port_mutex);
38 * lockdep: port->lock is initialized in two places, but we
39 * want only one lock-class:
41 static struct lock_class_key port_lock_key;
43 #define HIGH_BITS_OFFSET ((sizeof(long)-sizeof(int))*8)
45 static void uart_change_speed(struct tty_struct *tty, struct uart_state *state,
46 struct ktermios *old_termios);
47 static void uart_wait_until_sent(struct tty_struct *tty, int timeout);
48 static void uart_change_pm(struct uart_state *state,
49 enum uart_pm_state pm_state);
51 static void uart_port_shutdown(struct tty_port *port);
53 static int uart_dcd_enabled(struct uart_port *uport)
55 return !!(uport->status & UPSTAT_DCD_ENABLE);
58 static inline struct uart_port *uart_port_ref(struct uart_state *state)
60 if (atomic_add_unless(&state->refcount, 1, 0))
61 return state->uart_port;
65 static inline void uart_port_deref(struct uart_port *uport)
67 if (atomic_dec_and_test(&uport->state->refcount))
68 wake_up(&uport->state->remove_wait);
71 #define uart_port_lock(state, flags) \
73 struct uart_port *__uport = uart_port_ref(state); \
75 spin_lock_irqsave(&__uport->lock, flags); \
79 #define uart_port_unlock(uport, flags) \
81 struct uart_port *__uport = uport; \
83 spin_unlock_irqrestore(&__uport->lock, flags); \
84 uart_port_deref(__uport); \
88 static inline struct uart_port *uart_port_check(struct uart_state *state)
90 lockdep_assert_held(&state->port.mutex);
91 return state->uart_port;
95 * This routine is used by the interrupt handler to schedule processing in
96 * the software interrupt portion of the driver.
98 void uart_write_wakeup(struct uart_port *port)
100 struct uart_state *state = port->state;
102 * This means you called this function _after_ the port was
103 * closed. No cookie for you.
106 tty_port_tty_wakeup(&state->port);
109 static void uart_stop(struct tty_struct *tty)
111 struct uart_state *state = tty->driver_data;
112 struct uart_port *port;
115 port = uart_port_lock(state, flags);
117 port->ops->stop_tx(port);
118 uart_port_unlock(port, flags);
121 static void __uart_start(struct tty_struct *tty)
123 struct uart_state *state = tty->driver_data;
124 struct uart_port *port = state->uart_port;
126 if (port && !uart_tx_stopped(port))
127 port->ops->start_tx(port);
130 static void uart_start(struct tty_struct *tty)
132 struct uart_state *state = tty->driver_data;
133 struct uart_port *port;
136 port = uart_port_lock(state, flags);
138 uart_port_unlock(port, flags);
142 uart_update_mctrl(struct uart_port *port, unsigned int set, unsigned int clear)
147 spin_lock_irqsave(&port->lock, flags);
149 port->mctrl = (old & ~clear) | set;
150 if (old != port->mctrl)
151 port->ops->set_mctrl(port, port->mctrl);
152 spin_unlock_irqrestore(&port->lock, flags);
155 #define uart_set_mctrl(port, set) uart_update_mctrl(port, set, 0)
156 #define uart_clear_mctrl(port, clear) uart_update_mctrl(port, 0, clear)
158 static void uart_port_dtr_rts(struct uart_port *uport, int raise)
160 int rs485_on = uport->rs485_config &&
161 (uport->rs485.flags & SER_RS485_ENABLED);
162 int RTS_after_send = !!(uport->rs485.flags & SER_RS485_RTS_AFTER_SEND);
165 if (rs485_on && !RTS_after_send) {
166 uart_set_mctrl(uport, TIOCM_DTR);
167 uart_clear_mctrl(uport, TIOCM_RTS);
169 uart_set_mctrl(uport, TIOCM_DTR | TIOCM_RTS);
172 unsigned int clear = TIOCM_DTR;
174 clear |= (!rs485_on || !RTS_after_send) ? TIOCM_RTS : 0;
175 uart_clear_mctrl(uport, clear);
180 * Startup the port. This will be called once per open. All calls
181 * will be serialised by the per-port mutex.
183 static int uart_port_startup(struct tty_struct *tty, struct uart_state *state,
186 struct uart_port *uport = uart_port_check(state);
191 if (uport->type == PORT_UNKNOWN)
195 * Make sure the device is in D0 state.
197 uart_change_pm(state, UART_PM_STATE_ON);
200 * Initialise and allocate the transmit and temporary
203 page = get_zeroed_page(GFP_KERNEL);
207 uart_port_lock(state, flags);
208 if (!state->xmit.buf) {
209 state->xmit.buf = (unsigned char *) page;
210 uart_circ_clear(&state->xmit);
211 uart_port_unlock(uport, flags);
213 uart_port_unlock(uport, flags);
215 * Do not free() the page under the port lock, see
221 retval = uport->ops->startup(uport);
223 if (uart_console(uport) && uport->cons->cflag) {
224 tty->termios.c_cflag = uport->cons->cflag;
225 tty->termios.c_ispeed = uport->cons->ispeed;
226 tty->termios.c_ospeed = uport->cons->ospeed;
227 uport->cons->cflag = 0;
228 uport->cons->ispeed = 0;
229 uport->cons->ospeed = 0;
232 * Initialise the hardware port settings.
234 uart_change_speed(tty, state, NULL);
237 * Setup the RTS and DTR signals once the
238 * port is open and ready to respond.
240 if (init_hw && C_BAUD(tty))
241 uart_port_dtr_rts(uport, 1);
245 * This is to allow setserial on this port. People may want to set
246 * port/irq/type and then reconfigure the port properly if it failed
249 if (retval && capable(CAP_SYS_ADMIN))
255 static int uart_startup(struct tty_struct *tty, struct uart_state *state,
258 struct tty_port *port = &state->port;
261 if (tty_port_initialized(port))
264 retval = uart_port_startup(tty, state, init_hw);
266 set_bit(TTY_IO_ERROR, &tty->flags);
272 * This routine will shutdown a serial port; interrupts are disabled, and
273 * DTR is dropped if the hangup on close termio flag is on. Calls to
274 * uart_shutdown are serialised by the per-port semaphore.
276 * uport == NULL if uart_port has already been removed
278 static void uart_shutdown(struct tty_struct *tty, struct uart_state *state)
280 struct uart_port *uport = uart_port_check(state);
281 struct tty_port *port = &state->port;
283 char *xmit_buf = NULL;
286 * Set the TTY IO error marker
289 set_bit(TTY_IO_ERROR, &tty->flags);
291 if (tty_port_initialized(port)) {
292 tty_port_set_initialized(port, 0);
295 * Turn off DTR and RTS early.
297 if (uport && uart_console(uport) && tty) {
298 uport->cons->cflag = tty->termios.c_cflag;
299 uport->cons->ispeed = tty->termios.c_ispeed;
300 uport->cons->ospeed = tty->termios.c_ospeed;
303 if (!tty || C_HUPCL(tty))
304 uart_port_dtr_rts(uport, 0);
306 uart_port_shutdown(port);
310 * It's possible for shutdown to be called after suspend if we get
311 * a DCD drop (hangup) at just the right time. Clear suspended bit so
312 * we don't try to resume a port that has been shutdown.
314 tty_port_set_suspended(port, 0);
317 * Do not free() the transmit buffer page under the port lock since
318 * this can create various circular locking scenarios. For instance,
319 * console driver may need to allocate/free a debug object, which
320 * can endup in printk() recursion.
322 uart_port_lock(state, flags);
323 xmit_buf = state->xmit.buf;
324 state->xmit.buf = NULL;
325 uart_port_unlock(uport, flags);
328 free_page((unsigned long)xmit_buf);
332 * uart_update_timeout - update per-port FIFO timeout.
333 * @port: uart_port structure describing the port
334 * @cflag: termios cflag value
335 * @baud: speed of the port
337 * Set the port FIFO timeout value. The @cflag value should
338 * reflect the actual hardware settings.
341 uart_update_timeout(struct uart_port *port, unsigned int cflag,
346 size = tty_get_frame_size(cflag) * port->fifosize;
349 * Figure the timeout to send the above number of bits.
350 * Add .02 seconds of slop
352 port->timeout = (HZ * size) / baud + HZ/50;
355 EXPORT_SYMBOL(uart_update_timeout);
358 * uart_get_baud_rate - return baud rate for a particular port
359 * @port: uart_port structure describing the port in question.
360 * @termios: desired termios settings.
361 * @old: old termios (or NULL)
362 * @min: minimum acceptable baud rate
363 * @max: maximum acceptable baud rate
365 * Decode the termios structure into a numeric baud rate,
366 * taking account of the magic 38400 baud rate (with spd_*
367 * flags), and mapping the %B0 rate to 9600 baud.
369 * If the new baud rate is invalid, try the old termios setting.
370 * If it's still invalid, we try 9600 baud.
372 * Update the @termios structure to reflect the baud rate
373 * we're actually going to be using. Don't do this for the case
374 * where B0 is requested ("hang up").
377 uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
378 struct ktermios *old, unsigned int min, unsigned int max)
382 unsigned int altbaud;
384 upf_t flags = port->flags & UPF_SPD_MASK;
404 for (try = 0; try < 2; try++) {
405 baud = tty_termios_baud_rate(termios);
408 * The spd_hi, spd_vhi, spd_shi, spd_warp kludge...
411 if (try == 0 && baud == 38400)
415 * Special case: B0 rate.
422 if (baud >= min && baud <= max)
426 * Oops, the quotient was zero. Try again with
427 * the old baud rate if possible.
429 termios->c_cflag &= ~CBAUD;
431 baud = tty_termios_baud_rate(old);
433 tty_termios_encode_baud_rate(termios,
440 * As a last resort, if the range cannot be met then clip to
441 * the nearest chip supported rate.
445 tty_termios_encode_baud_rate(termios,
448 tty_termios_encode_baud_rate(termios,
452 /* Should never happen */
457 EXPORT_SYMBOL(uart_get_baud_rate);
460 * uart_get_divisor - return uart clock divisor
461 * @port: uart_port structure describing the port.
462 * @baud: desired baud rate
464 * Calculate the uart clock divisor for the port.
467 uart_get_divisor(struct uart_port *port, unsigned int baud)
472 * Old custom speed handling.
474 if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST)
475 quot = port->custom_divisor;
477 quot = DIV_ROUND_CLOSEST(port->uartclk, 16 * baud);
482 EXPORT_SYMBOL(uart_get_divisor);
484 /* Caller holds port mutex */
485 static void uart_change_speed(struct tty_struct *tty, struct uart_state *state,
486 struct ktermios *old_termios)
488 struct uart_port *uport = uart_port_check(state);
489 struct ktermios *termios;
493 * If we have no tty, termios, or the port does not exist,
494 * then we can't set the parameters for this port.
496 if (!tty || uport->type == PORT_UNKNOWN)
499 termios = &tty->termios;
500 uport->ops->set_termios(uport, termios, old_termios);
503 * Set modem status enables based on termios cflag
505 spin_lock_irq(&uport->lock);
506 if (termios->c_cflag & CRTSCTS)
507 uport->status |= UPSTAT_CTS_ENABLE;
509 uport->status &= ~UPSTAT_CTS_ENABLE;
511 if (termios->c_cflag & CLOCAL)
512 uport->status &= ~UPSTAT_DCD_ENABLE;
514 uport->status |= UPSTAT_DCD_ENABLE;
516 /* reset sw-assisted CTS flow control based on (possibly) new mode */
517 hw_stopped = uport->hw_stopped;
518 uport->hw_stopped = uart_softcts_mode(uport) &&
519 !(uport->ops->get_mctrl(uport) & TIOCM_CTS);
520 if (uport->hw_stopped) {
522 uport->ops->stop_tx(uport);
527 spin_unlock_irq(&uport->lock);
530 static int uart_put_char(struct tty_struct *tty, unsigned char c)
532 struct uart_state *state = tty->driver_data;
533 struct uart_port *port;
534 struct circ_buf *circ;
539 port = uart_port_lock(state, flags);
541 uart_port_unlock(port, flags);
545 if (port && uart_circ_chars_free(circ) != 0) {
546 circ->buf[circ->head] = c;
547 circ->head = (circ->head + 1) & (UART_XMIT_SIZE - 1);
550 uart_port_unlock(port, flags);
554 static void uart_flush_chars(struct tty_struct *tty)
559 static int uart_write(struct tty_struct *tty,
560 const unsigned char *buf, int count)
562 struct uart_state *state = tty->driver_data;
563 struct uart_port *port;
564 struct circ_buf *circ;
569 * This means you called this function _after_ the port was
570 * closed. No cookie for you.
577 port = uart_port_lock(state, flags);
580 uart_port_unlock(port, flags);
585 c = CIRC_SPACE_TO_END(circ->head, circ->tail, UART_XMIT_SIZE);
590 memcpy(circ->buf + circ->head, buf, c);
591 circ->head = (circ->head + c) & (UART_XMIT_SIZE - 1);
598 uart_port_unlock(port, flags);
602 static unsigned int uart_write_room(struct tty_struct *tty)
604 struct uart_state *state = tty->driver_data;
605 struct uart_port *port;
609 port = uart_port_lock(state, flags);
610 ret = uart_circ_chars_free(&state->xmit);
611 uart_port_unlock(port, flags);
615 static unsigned int uart_chars_in_buffer(struct tty_struct *tty)
617 struct uart_state *state = tty->driver_data;
618 struct uart_port *port;
622 port = uart_port_lock(state, flags);
623 ret = uart_circ_chars_pending(&state->xmit);
624 uart_port_unlock(port, flags);
628 static void uart_flush_buffer(struct tty_struct *tty)
630 struct uart_state *state = tty->driver_data;
631 struct uart_port *port;
635 * This means you called this function _after_ the port was
636 * closed. No cookie for you.
643 pr_debug("uart_flush_buffer(%d) called\n", tty->index);
645 port = uart_port_lock(state, flags);
648 uart_circ_clear(&state->xmit);
649 if (port->ops->flush_buffer)
650 port->ops->flush_buffer(port);
651 uart_port_unlock(port, flags);
652 tty_port_tty_wakeup(&state->port);
656 * This function is used to send a high-priority XON/XOFF character to
659 static void uart_send_xchar(struct tty_struct *tty, char ch)
661 struct uart_state *state = tty->driver_data;
662 struct uart_port *port;
665 port = uart_port_ref(state);
669 if (port->ops->send_xchar)
670 port->ops->send_xchar(port, ch);
672 spin_lock_irqsave(&port->lock, flags);
675 port->ops->start_tx(port);
676 spin_unlock_irqrestore(&port->lock, flags);
678 uart_port_deref(port);
681 static void uart_throttle(struct tty_struct *tty)
683 struct uart_state *state = tty->driver_data;
684 upstat_t mask = UPSTAT_SYNC_FIFO;
685 struct uart_port *port;
687 port = uart_port_ref(state);
692 mask |= UPSTAT_AUTOXOFF;
694 mask |= UPSTAT_AUTORTS;
696 if (port->status & mask) {
697 port->ops->throttle(port);
698 mask &= ~port->status;
701 if (mask & UPSTAT_AUTORTS)
702 uart_clear_mctrl(port, TIOCM_RTS);
704 if (mask & UPSTAT_AUTOXOFF)
705 uart_send_xchar(tty, STOP_CHAR(tty));
707 uart_port_deref(port);
710 static void uart_unthrottle(struct tty_struct *tty)
712 struct uart_state *state = tty->driver_data;
713 upstat_t mask = UPSTAT_SYNC_FIFO;
714 struct uart_port *port;
716 port = uart_port_ref(state);
721 mask |= UPSTAT_AUTOXOFF;
723 mask |= UPSTAT_AUTORTS;
725 if (port->status & mask) {
726 port->ops->unthrottle(port);
727 mask &= ~port->status;
730 if (mask & UPSTAT_AUTORTS)
731 uart_set_mctrl(port, TIOCM_RTS);
733 if (mask & UPSTAT_AUTOXOFF)
734 uart_send_xchar(tty, START_CHAR(tty));
736 uart_port_deref(port);
739 static int uart_get_info(struct tty_port *port, struct serial_struct *retinfo)
741 struct uart_state *state = container_of(port, struct uart_state, port);
742 struct uart_port *uport;
746 * Ensure the state we copy is consistent and no hardware changes
749 mutex_lock(&port->mutex);
750 uport = uart_port_check(state);
754 retinfo->type = uport->type;
755 retinfo->line = uport->line;
756 retinfo->port = uport->iobase;
757 if (HIGH_BITS_OFFSET)
758 retinfo->port_high = (long) uport->iobase >> HIGH_BITS_OFFSET;
759 retinfo->irq = uport->irq;
760 retinfo->flags = (__force int)uport->flags;
761 retinfo->xmit_fifo_size = uport->fifosize;
762 retinfo->baud_base = uport->uartclk / 16;
763 retinfo->close_delay = jiffies_to_msecs(port->close_delay) / 10;
764 retinfo->closing_wait = port->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
765 ASYNC_CLOSING_WAIT_NONE :
766 jiffies_to_msecs(port->closing_wait) / 10;
767 retinfo->custom_divisor = uport->custom_divisor;
768 retinfo->hub6 = uport->hub6;
769 retinfo->io_type = uport->iotype;
770 retinfo->iomem_reg_shift = uport->regshift;
771 retinfo->iomem_base = (void *)(unsigned long)uport->mapbase;
775 mutex_unlock(&port->mutex);
779 static int uart_get_info_user(struct tty_struct *tty,
780 struct serial_struct *ss)
782 struct uart_state *state = tty->driver_data;
783 struct tty_port *port = &state->port;
785 return uart_get_info(port, ss) < 0 ? -EIO : 0;
788 static int uart_set_info(struct tty_struct *tty, struct tty_port *port,
789 struct uart_state *state,
790 struct serial_struct *new_info)
792 struct uart_port *uport = uart_port_check(state);
793 unsigned long new_port;
794 unsigned int change_irq, change_port, closing_wait;
795 unsigned int old_custom_divisor, close_delay;
796 upf_t old_flags, new_flags;
802 new_port = new_info->port;
803 if (HIGH_BITS_OFFSET)
804 new_port += (unsigned long) new_info->port_high << HIGH_BITS_OFFSET;
806 new_info->irq = irq_canonicalize(new_info->irq);
807 close_delay = msecs_to_jiffies(new_info->close_delay * 10);
808 closing_wait = new_info->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
809 ASYNC_CLOSING_WAIT_NONE :
810 msecs_to_jiffies(new_info->closing_wait * 10);
813 change_irq = !(uport->flags & UPF_FIXED_PORT)
814 && new_info->irq != uport->irq;
817 * Since changing the 'type' of the port changes its resource
818 * allocations, we should treat type changes the same as
821 change_port = !(uport->flags & UPF_FIXED_PORT)
822 && (new_port != uport->iobase ||
823 (unsigned long)new_info->iomem_base != uport->mapbase ||
824 new_info->hub6 != uport->hub6 ||
825 new_info->io_type != uport->iotype ||
826 new_info->iomem_reg_shift != uport->regshift ||
827 new_info->type != uport->type);
829 old_flags = uport->flags;
830 new_flags = (__force upf_t)new_info->flags;
831 old_custom_divisor = uport->custom_divisor;
833 if (!capable(CAP_SYS_ADMIN)) {
835 if (change_irq || change_port ||
836 (new_info->baud_base != uport->uartclk / 16) ||
837 (close_delay != port->close_delay) ||
838 (closing_wait != port->closing_wait) ||
839 (new_info->xmit_fifo_size &&
840 new_info->xmit_fifo_size != uport->fifosize) ||
841 (((new_flags ^ old_flags) & ~UPF_USR_MASK) != 0))
843 uport->flags = ((uport->flags & ~UPF_USR_MASK) |
844 (new_flags & UPF_USR_MASK));
845 uport->custom_divisor = new_info->custom_divisor;
849 if (change_irq || change_port) {
850 retval = security_locked_down(LOCKDOWN_TIOCSSERIAL);
856 * Ask the low level driver to verify the settings.
858 if (uport->ops->verify_port)
859 retval = uport->ops->verify_port(uport, new_info);
861 if ((new_info->irq >= nr_irqs) || (new_info->irq < 0) ||
862 (new_info->baud_base < 9600))
868 if (change_port || change_irq) {
872 * Make sure that we are the sole user of this port.
874 if (tty_port_users(port) > 1)
878 * We need to shutdown the serial port at the old
879 * port/type/irq combination.
881 uart_shutdown(tty, state);
885 unsigned long old_iobase, old_mapbase;
886 unsigned int old_type, old_iotype, old_hub6, old_shift;
888 old_iobase = uport->iobase;
889 old_mapbase = uport->mapbase;
890 old_type = uport->type;
891 old_hub6 = uport->hub6;
892 old_iotype = uport->iotype;
893 old_shift = uport->regshift;
896 * Free and release old regions
898 if (old_type != PORT_UNKNOWN && uport->ops->release_port)
899 uport->ops->release_port(uport);
901 uport->iobase = new_port;
902 uport->type = new_info->type;
903 uport->hub6 = new_info->hub6;
904 uport->iotype = new_info->io_type;
905 uport->regshift = new_info->iomem_reg_shift;
906 uport->mapbase = (unsigned long)new_info->iomem_base;
909 * Claim and map the new regions
911 if (uport->type != PORT_UNKNOWN && uport->ops->request_port) {
912 retval = uport->ops->request_port(uport);
914 /* Always success - Jean II */
919 * If we fail to request resources for the
920 * new port, try to restore the old settings.
923 uport->iobase = old_iobase;
924 uport->type = old_type;
925 uport->hub6 = old_hub6;
926 uport->iotype = old_iotype;
927 uport->regshift = old_shift;
928 uport->mapbase = old_mapbase;
930 if (old_type != PORT_UNKNOWN) {
931 retval = uport->ops->request_port(uport);
933 * If we failed to restore the old settings,
937 uport->type = PORT_UNKNOWN;
945 /* Added to return the correct error -Ram Gupta */
951 uport->irq = new_info->irq;
952 if (!(uport->flags & UPF_FIXED_PORT))
953 uport->uartclk = new_info->baud_base * 16;
954 uport->flags = (uport->flags & ~UPF_CHANGE_MASK) |
955 (new_flags & UPF_CHANGE_MASK);
956 uport->custom_divisor = new_info->custom_divisor;
957 port->close_delay = close_delay;
958 port->closing_wait = closing_wait;
959 if (new_info->xmit_fifo_size)
960 uport->fifosize = new_info->xmit_fifo_size;
964 if (uport->type == PORT_UNKNOWN)
966 if (tty_port_initialized(port)) {
967 if (((old_flags ^ uport->flags) & UPF_SPD_MASK) ||
968 old_custom_divisor != uport->custom_divisor) {
970 * If they're setting up a custom divisor or speed,
971 * instead of clearing it, then bitch about it.
973 if (uport->flags & UPF_SPD_MASK) {
974 dev_notice_ratelimited(uport->dev,
975 "%s sets custom speed on %s. This is deprecated.\n",
977 tty_name(port->tty));
979 uart_change_speed(tty, state, NULL);
982 retval = uart_startup(tty, state, 1);
984 tty_port_set_initialized(port, true);
992 static int uart_set_info_user(struct tty_struct *tty, struct serial_struct *ss)
994 struct uart_state *state = tty->driver_data;
995 struct tty_port *port = &state->port;
998 down_write(&tty->termios_rwsem);
1000 * This semaphore protects port->count. It is also
1001 * very useful to prevent opens. Also, take the
1002 * port configuration semaphore to make sure that a
1003 * module insertion/removal doesn't change anything
1006 mutex_lock(&port->mutex);
1007 retval = uart_set_info(tty, port, state, ss);
1008 mutex_unlock(&port->mutex);
1009 up_write(&tty->termios_rwsem);
1014 * uart_get_lsr_info - get line status register info
1015 * @tty: tty associated with the UART
1016 * @state: UART being queried
1017 * @value: returned modem value
1019 static int uart_get_lsr_info(struct tty_struct *tty,
1020 struct uart_state *state, unsigned int __user *value)
1022 struct uart_port *uport = uart_port_check(state);
1023 unsigned int result;
1025 result = uport->ops->tx_empty(uport);
1028 * If we're about to load something into the transmit
1029 * register, we'll pretend the transmitter isn't empty to
1030 * avoid a race condition (depending on when the transmit
1031 * interrupt happens).
1033 if (uport->x_char ||
1034 ((uart_circ_chars_pending(&state->xmit) > 0) &&
1035 !uart_tx_stopped(uport)))
1036 result &= ~TIOCSER_TEMT;
1038 return put_user(result, value);
1041 static int uart_tiocmget(struct tty_struct *tty)
1043 struct uart_state *state = tty->driver_data;
1044 struct tty_port *port = &state->port;
1045 struct uart_port *uport;
1048 mutex_lock(&port->mutex);
1049 uport = uart_port_check(state);
1053 if (!tty_io_error(tty)) {
1054 result = uport->mctrl;
1055 spin_lock_irq(&uport->lock);
1056 result |= uport->ops->get_mctrl(uport);
1057 spin_unlock_irq(&uport->lock);
1060 mutex_unlock(&port->mutex);
1065 uart_tiocmset(struct tty_struct *tty, unsigned int set, unsigned int clear)
1067 struct uart_state *state = tty->driver_data;
1068 struct tty_port *port = &state->port;
1069 struct uart_port *uport;
1072 mutex_lock(&port->mutex);
1073 uport = uart_port_check(state);
1077 if (!tty_io_error(tty)) {
1078 if (uport->rs485.flags & SER_RS485_ENABLED) {
1080 clear &= ~TIOCM_RTS;
1083 uart_update_mctrl(uport, set, clear);
1087 mutex_unlock(&port->mutex);
1091 static int uart_break_ctl(struct tty_struct *tty, int break_state)
1093 struct uart_state *state = tty->driver_data;
1094 struct tty_port *port = &state->port;
1095 struct uart_port *uport;
1098 mutex_lock(&port->mutex);
1099 uport = uart_port_check(state);
1103 if (uport->type != PORT_UNKNOWN && uport->ops->break_ctl)
1104 uport->ops->break_ctl(uport, break_state);
1107 mutex_unlock(&port->mutex);
1111 static int uart_do_autoconfig(struct tty_struct *tty, struct uart_state *state)
1113 struct tty_port *port = &state->port;
1114 struct uart_port *uport;
1117 if (!capable(CAP_SYS_ADMIN))
1121 * Take the per-port semaphore. This prevents count from
1122 * changing, and hence any extra opens of the port while
1123 * we're auto-configuring.
1125 if (mutex_lock_interruptible(&port->mutex))
1126 return -ERESTARTSYS;
1128 uport = uart_port_check(state);
1135 if (tty_port_users(port) == 1) {
1136 uart_shutdown(tty, state);
1139 * If we already have a port type configured,
1140 * we must release its resources.
1142 if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
1143 uport->ops->release_port(uport);
1145 flags = UART_CONFIG_TYPE;
1146 if (uport->flags & UPF_AUTO_IRQ)
1147 flags |= UART_CONFIG_IRQ;
1150 * This will claim the ports resources if
1153 uport->ops->config_port(uport, flags);
1155 ret = uart_startup(tty, state, 1);
1157 tty_port_set_initialized(port, true);
1162 mutex_unlock(&port->mutex);
1166 static void uart_enable_ms(struct uart_port *uport)
1169 * Force modem status interrupts on
1171 if (uport->ops->enable_ms)
1172 uport->ops->enable_ms(uport);
1176 * Wait for any of the 4 modem inputs (DCD,RI,DSR,CTS) to change
1177 * - mask passed in arg for lines of interest
1178 * (use |'ed TIOCM_RNG/DSR/CD/CTS for masking)
1179 * Caller should use TIOCGICOUNT to see which one it was
1181 * FIXME: This wants extracting into a common all driver implementation
1182 * of TIOCMWAIT using tty_port.
1184 static int uart_wait_modem_status(struct uart_state *state, unsigned long arg)
1186 struct uart_port *uport;
1187 struct tty_port *port = &state->port;
1188 DECLARE_WAITQUEUE(wait, current);
1189 struct uart_icount cprev, cnow;
1193 * note the counters on entry
1195 uport = uart_port_ref(state);
1198 spin_lock_irq(&uport->lock);
1199 memcpy(&cprev, &uport->icount, sizeof(struct uart_icount));
1200 uart_enable_ms(uport);
1201 spin_unlock_irq(&uport->lock);
1203 add_wait_queue(&port->delta_msr_wait, &wait);
1205 spin_lock_irq(&uport->lock);
1206 memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1207 spin_unlock_irq(&uport->lock);
1209 set_current_state(TASK_INTERRUPTIBLE);
1211 if (((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
1212 ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
1213 ((arg & TIOCM_CD) && (cnow.dcd != cprev.dcd)) ||
1214 ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts))) {
1221 /* see if a signal did it */
1222 if (signal_pending(current)) {
1229 __set_current_state(TASK_RUNNING);
1230 remove_wait_queue(&port->delta_msr_wait, &wait);
1231 uart_port_deref(uport);
1237 * Get counter of input serial line interrupts (DCD,RI,DSR,CTS)
1238 * Return: write counters to the user passed counter struct
1239 * NB: both 1->0 and 0->1 transitions are counted except for
1240 * RI where only 0->1 is counted.
1242 static int uart_get_icount(struct tty_struct *tty,
1243 struct serial_icounter_struct *icount)
1245 struct uart_state *state = tty->driver_data;
1246 struct uart_icount cnow;
1247 struct uart_port *uport;
1249 uport = uart_port_ref(state);
1252 spin_lock_irq(&uport->lock);
1253 memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1254 spin_unlock_irq(&uport->lock);
1255 uart_port_deref(uport);
1257 icount->cts = cnow.cts;
1258 icount->dsr = cnow.dsr;
1259 icount->rng = cnow.rng;
1260 icount->dcd = cnow.dcd;
1261 icount->rx = cnow.rx;
1262 icount->tx = cnow.tx;
1263 icount->frame = cnow.frame;
1264 icount->overrun = cnow.overrun;
1265 icount->parity = cnow.parity;
1266 icount->brk = cnow.brk;
1267 icount->buf_overrun = cnow.buf_overrun;
1272 static int uart_get_rs485_config(struct uart_port *port,
1273 struct serial_rs485 __user *rs485)
1275 unsigned long flags;
1276 struct serial_rs485 aux;
1278 spin_lock_irqsave(&port->lock, flags);
1280 spin_unlock_irqrestore(&port->lock, flags);
1282 if (copy_to_user(rs485, &aux, sizeof(aux)))
1288 static int uart_set_rs485_config(struct uart_port *port,
1289 struct serial_rs485 __user *rs485_user)
1291 struct serial_rs485 rs485;
1293 unsigned long flags;
1295 if (!port->rs485_config)
1298 if (copy_from_user(&rs485, rs485_user, sizeof(*rs485_user)))
1301 spin_lock_irqsave(&port->lock, flags);
1302 ret = port->rs485_config(port, &rs485);
1303 spin_unlock_irqrestore(&port->lock, flags);
1307 if (copy_to_user(rs485_user, &port->rs485, sizeof(port->rs485)))
1313 static int uart_get_iso7816_config(struct uart_port *port,
1314 struct serial_iso7816 __user *iso7816)
1316 unsigned long flags;
1317 struct serial_iso7816 aux;
1319 if (!port->iso7816_config)
1322 spin_lock_irqsave(&port->lock, flags);
1323 aux = port->iso7816;
1324 spin_unlock_irqrestore(&port->lock, flags);
1326 if (copy_to_user(iso7816, &aux, sizeof(aux)))
1332 static int uart_set_iso7816_config(struct uart_port *port,
1333 struct serial_iso7816 __user *iso7816_user)
1335 struct serial_iso7816 iso7816;
1337 unsigned long flags;
1339 if (!port->iso7816_config)
1342 if (copy_from_user(&iso7816, iso7816_user, sizeof(*iso7816_user)))
1346 * There are 5 words reserved for future use. Check that userspace
1347 * doesn't put stuff in there to prevent breakages in the future.
1349 for (i = 0; i < 5; i++)
1350 if (iso7816.reserved[i])
1353 spin_lock_irqsave(&port->lock, flags);
1354 ret = port->iso7816_config(port, &iso7816);
1355 spin_unlock_irqrestore(&port->lock, flags);
1359 if (copy_to_user(iso7816_user, &port->iso7816, sizeof(port->iso7816)))
1366 * Called via sys_ioctl. We can use spin_lock_irq() here.
1369 uart_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
1371 struct uart_state *state = tty->driver_data;
1372 struct tty_port *port = &state->port;
1373 struct uart_port *uport;
1374 void __user *uarg = (void __user *)arg;
1375 int ret = -ENOIOCTLCMD;
1379 * These ioctls don't rely on the hardware to be present.
1383 down_write(&tty->termios_rwsem);
1384 ret = uart_do_autoconfig(tty, state);
1385 up_write(&tty->termios_rwsem);
1389 if (ret != -ENOIOCTLCMD)
1392 if (tty_io_error(tty)) {
1398 * The following should only be used when hardware is present.
1402 ret = uart_wait_modem_status(state, arg);
1406 if (ret != -ENOIOCTLCMD)
1409 mutex_lock(&port->mutex);
1410 uport = uart_port_check(state);
1412 if (!uport || tty_io_error(tty)) {
1418 * All these rely on hardware being present and need to be
1419 * protected against the tty being hung up.
1423 case TIOCSERGETLSR: /* Get line status register */
1424 ret = uart_get_lsr_info(tty, state, uarg);
1428 ret = uart_get_rs485_config(uport, uarg);
1432 ret = uart_set_rs485_config(uport, uarg);
1436 ret = uart_set_iso7816_config(state->uart_port, uarg);
1440 ret = uart_get_iso7816_config(state->uart_port, uarg);
1443 if (uport->ops->ioctl)
1444 ret = uport->ops->ioctl(uport, cmd, arg);
1448 mutex_unlock(&port->mutex);
1453 static void uart_set_ldisc(struct tty_struct *tty)
1455 struct uart_state *state = tty->driver_data;
1456 struct uart_port *uport;
1457 struct tty_port *port = &state->port;
1459 if (!tty_port_initialized(port))
1462 mutex_lock(&state->port.mutex);
1463 uport = uart_port_check(state);
1464 if (uport && uport->ops->set_ldisc)
1465 uport->ops->set_ldisc(uport, &tty->termios);
1466 mutex_unlock(&state->port.mutex);
1469 static void uart_set_termios(struct tty_struct *tty,
1470 struct ktermios *old_termios)
1472 struct uart_state *state = tty->driver_data;
1473 struct uart_port *uport;
1474 unsigned int cflag = tty->termios.c_cflag;
1475 unsigned int iflag_mask = IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK;
1476 bool sw_changed = false;
1478 mutex_lock(&state->port.mutex);
1479 uport = uart_port_check(state);
1484 * Drivers doing software flow control also need to know
1485 * about changes to these input settings.
1487 if (uport->flags & UPF_SOFT_FLOW) {
1488 iflag_mask |= IXANY|IXON|IXOFF;
1490 tty->termios.c_cc[VSTART] != old_termios->c_cc[VSTART] ||
1491 tty->termios.c_cc[VSTOP] != old_termios->c_cc[VSTOP];
1495 * These are the bits that are used to setup various
1496 * flags in the low level driver. We can ignore the Bfoo
1497 * bits in c_cflag; c_[io]speed will always be set
1498 * appropriately by set_termios() in tty_ioctl.c
1500 if ((cflag ^ old_termios->c_cflag) == 0 &&
1501 tty->termios.c_ospeed == old_termios->c_ospeed &&
1502 tty->termios.c_ispeed == old_termios->c_ispeed &&
1503 ((tty->termios.c_iflag ^ old_termios->c_iflag) & iflag_mask) == 0 &&
1508 uart_change_speed(tty, state, old_termios);
1509 /* reload cflag from termios; port driver may have overridden flags */
1510 cflag = tty->termios.c_cflag;
1512 /* Handle transition to B0 status */
1513 if ((old_termios->c_cflag & CBAUD) && !(cflag & CBAUD))
1514 uart_clear_mctrl(uport, TIOCM_RTS | TIOCM_DTR);
1515 /* Handle transition away from B0 status */
1516 else if (!(old_termios->c_cflag & CBAUD) && (cflag & CBAUD)) {
1517 unsigned int mask = TIOCM_DTR;
1519 if (!(cflag & CRTSCTS) || !tty_throttled(tty))
1521 uart_set_mctrl(uport, mask);
1524 mutex_unlock(&state->port.mutex);
1528 * Calls to uart_close() are serialised via the tty_lock in
1529 * drivers/tty/tty_io.c:tty_release()
1530 * drivers/tty/tty_io.c:do_tty_hangup()
1532 static void uart_close(struct tty_struct *tty, struct file *filp)
1534 struct uart_state *state = tty->driver_data;
1537 struct uart_driver *drv = tty->driver->driver_state;
1538 struct tty_port *port;
1540 state = drv->state + tty->index;
1541 port = &state->port;
1542 spin_lock_irq(&port->lock);
1544 spin_unlock_irq(&port->lock);
1548 pr_debug("uart_close(%d) called\n", tty->index);
1550 tty_port_close(tty->port, tty, filp);
1553 static void uart_tty_port_shutdown(struct tty_port *port)
1555 struct uart_state *state = container_of(port, struct uart_state, port);
1556 struct uart_port *uport = uart_port_check(state);
1560 * At this point, we stop accepting input. To do this, we
1561 * disable the receive line status interrupts.
1563 if (WARN(!uport, "detached port still initialized!\n"))
1566 spin_lock_irq(&uport->lock);
1567 uport->ops->stop_rx(uport);
1568 spin_unlock_irq(&uport->lock);
1570 uart_port_shutdown(port);
1573 * It's possible for shutdown to be called after suspend if we get
1574 * a DCD drop (hangup) at just the right time. Clear suspended bit so
1575 * we don't try to resume a port that has been shutdown.
1577 tty_port_set_suspended(port, 0);
1580 * Free the transmit buffer.
1582 spin_lock_irq(&uport->lock);
1583 buf = state->xmit.buf;
1584 state->xmit.buf = NULL;
1585 spin_unlock_irq(&uport->lock);
1588 free_page((unsigned long)buf);
1590 uart_change_pm(state, UART_PM_STATE_OFF);
1593 static void uart_wait_until_sent(struct tty_struct *tty, int timeout)
1595 struct uart_state *state = tty->driver_data;
1596 struct uart_port *port;
1597 unsigned long char_time, expire;
1599 port = uart_port_ref(state);
1603 if (port->type == PORT_UNKNOWN || port->fifosize == 0) {
1604 uart_port_deref(port);
1609 * Set the check interval to be 1/5 of the estimated time to
1610 * send a single character, and make it at least 1. The check
1611 * interval should also be less than the timeout.
1613 * Note: we have to use pretty tight timings here to satisfy
1616 char_time = (port->timeout - HZ/50) / port->fifosize;
1617 char_time = char_time / 5;
1620 if (timeout && timeout < char_time)
1621 char_time = timeout;
1624 * If the transmitter hasn't cleared in twice the approximate
1625 * amount of time to send the entire FIFO, it probably won't
1626 * ever clear. This assumes the UART isn't doing flow
1627 * control, which is currently the case. Hence, if it ever
1628 * takes longer than port->timeout, this is probably due to a
1629 * UART bug of some kind. So, we clamp the timeout parameter at
1632 if (timeout == 0 || timeout > 2 * port->timeout)
1633 timeout = 2 * port->timeout;
1635 expire = jiffies + timeout;
1637 pr_debug("uart_wait_until_sent(%d), jiffies=%lu, expire=%lu...\n",
1638 port->line, jiffies, expire);
1641 * Check whether the transmitter is empty every 'char_time'.
1642 * 'timeout' / 'expire' give us the maximum amount of time
1645 while (!port->ops->tx_empty(port)) {
1646 msleep_interruptible(jiffies_to_msecs(char_time));
1647 if (signal_pending(current))
1649 if (time_after(jiffies, expire))
1652 uart_port_deref(port);
1656 * Calls to uart_hangup() are serialised by the tty_lock in
1657 * drivers/tty/tty_io.c:do_tty_hangup()
1658 * This runs from a workqueue and can sleep for a _short_ time only.
1660 static void uart_hangup(struct tty_struct *tty)
1662 struct uart_state *state = tty->driver_data;
1663 struct tty_port *port = &state->port;
1664 struct uart_port *uport;
1665 unsigned long flags;
1667 pr_debug("uart_hangup(%d)\n", tty->index);
1669 mutex_lock(&port->mutex);
1670 uport = uart_port_check(state);
1671 WARN(!uport, "hangup of detached port!\n");
1673 if (tty_port_active(port)) {
1674 uart_flush_buffer(tty);
1675 uart_shutdown(tty, state);
1676 spin_lock_irqsave(&port->lock, flags);
1678 spin_unlock_irqrestore(&port->lock, flags);
1679 tty_port_set_active(port, 0);
1680 tty_port_tty_set(port, NULL);
1681 if (uport && !uart_console(uport))
1682 uart_change_pm(state, UART_PM_STATE_OFF);
1683 wake_up_interruptible(&port->open_wait);
1684 wake_up_interruptible(&port->delta_msr_wait);
1686 mutex_unlock(&port->mutex);
1689 /* uport == NULL if uart_port has already been removed */
1690 static void uart_port_shutdown(struct tty_port *port)
1692 struct uart_state *state = container_of(port, struct uart_state, port);
1693 struct uart_port *uport = uart_port_check(state);
1696 * clear delta_msr_wait queue to avoid mem leaks: we may free
1697 * the irq here so the queue might never be woken up. Note
1698 * that we won't end up waiting on delta_msr_wait again since
1699 * any outstanding file descriptors should be pointing at
1700 * hung_up_tty_fops now.
1702 wake_up_interruptible(&port->delta_msr_wait);
1705 /* Free the IRQ and disable the port. */
1706 uport->ops->shutdown(uport);
1708 /* Ensure that the IRQ handler isn't running on another CPU. */
1709 synchronize_irq(uport->irq);
1713 static int uart_carrier_raised(struct tty_port *port)
1715 struct uart_state *state = container_of(port, struct uart_state, port);
1716 struct uart_port *uport;
1719 uport = uart_port_ref(state);
1721 * Should never observe uport == NULL since checks for hangup should
1722 * abort the tty_port_block_til_ready() loop before checking for carrier
1723 * raised -- but report carrier raised if it does anyway so open will
1724 * continue and not sleep
1726 if (WARN_ON(!uport))
1728 spin_lock_irq(&uport->lock);
1729 uart_enable_ms(uport);
1730 mctrl = uport->ops->get_mctrl(uport);
1731 spin_unlock_irq(&uport->lock);
1732 uart_port_deref(uport);
1733 if (mctrl & TIOCM_CAR)
1738 static void uart_dtr_rts(struct tty_port *port, int raise)
1740 struct uart_state *state = container_of(port, struct uart_state, port);
1741 struct uart_port *uport;
1743 uport = uart_port_ref(state);
1746 uart_port_dtr_rts(uport, raise);
1747 uart_port_deref(uport);
1750 static int uart_install(struct tty_driver *driver, struct tty_struct *tty)
1752 struct uart_driver *drv = driver->driver_state;
1753 struct uart_state *state = drv->state + tty->index;
1755 tty->driver_data = state;
1757 return tty_standard_install(driver, tty);
1761 * Calls to uart_open are serialised by the tty_lock in
1762 * drivers/tty/tty_io.c:tty_open()
1763 * Note that if this fails, then uart_close() _will_ be called.
1765 * In time, we want to scrap the "opening nonpresent ports"
1766 * behaviour and implement an alternative way for setserial
1767 * to set base addresses/ports/types. This will allow us to
1768 * get rid of a certain amount of extra tests.
1770 static int uart_open(struct tty_struct *tty, struct file *filp)
1772 struct uart_state *state = tty->driver_data;
1775 retval = tty_port_open(&state->port, tty, filp);
1782 static int uart_port_activate(struct tty_port *port, struct tty_struct *tty)
1784 struct uart_state *state = container_of(port, struct uart_state, port);
1785 struct uart_port *uport;
1788 uport = uart_port_check(state);
1789 if (!uport || uport->flags & UPF_DEAD)
1793 * Start up the serial port.
1795 ret = uart_startup(tty, state, 0);
1797 tty_port_set_active(port, 1);
1802 static const char *uart_type(struct uart_port *port)
1804 const char *str = NULL;
1806 if (port->ops->type)
1807 str = port->ops->type(port);
1815 #ifdef CONFIG_PROC_FS
1817 static void uart_line_info(struct seq_file *m, struct uart_driver *drv, int i)
1819 struct uart_state *state = drv->state + i;
1820 struct tty_port *port = &state->port;
1821 enum uart_pm_state pm_state;
1822 struct uart_port *uport;
1824 unsigned int status;
1827 mutex_lock(&port->mutex);
1828 uport = uart_port_check(state);
1832 mmio = uport->iotype >= UPIO_MEM;
1833 seq_printf(m, "%d: uart:%s %s%08llX irq:%d",
1834 uport->line, uart_type(uport),
1835 mmio ? "mmio:0x" : "port:",
1836 mmio ? (unsigned long long)uport->mapbase
1837 : (unsigned long long)uport->iobase,
1840 if (uport->type == PORT_UNKNOWN) {
1845 if (capable(CAP_SYS_ADMIN)) {
1846 pm_state = state->pm_state;
1847 if (pm_state != UART_PM_STATE_ON)
1848 uart_change_pm(state, UART_PM_STATE_ON);
1849 spin_lock_irq(&uport->lock);
1850 status = uport->ops->get_mctrl(uport);
1851 spin_unlock_irq(&uport->lock);
1852 if (pm_state != UART_PM_STATE_ON)
1853 uart_change_pm(state, pm_state);
1855 seq_printf(m, " tx:%d rx:%d",
1856 uport->icount.tx, uport->icount.rx);
1857 if (uport->icount.frame)
1858 seq_printf(m, " fe:%d", uport->icount.frame);
1859 if (uport->icount.parity)
1860 seq_printf(m, " pe:%d", uport->icount.parity);
1861 if (uport->icount.brk)
1862 seq_printf(m, " brk:%d", uport->icount.brk);
1863 if (uport->icount.overrun)
1864 seq_printf(m, " oe:%d", uport->icount.overrun);
1865 if (uport->icount.buf_overrun)
1866 seq_printf(m, " bo:%d", uport->icount.buf_overrun);
1868 #define INFOBIT(bit, str) \
1869 if (uport->mctrl & (bit)) \
1870 strncat(stat_buf, (str), sizeof(stat_buf) - \
1871 strlen(stat_buf) - 2)
1872 #define STATBIT(bit, str) \
1873 if (status & (bit)) \
1874 strncat(stat_buf, (str), sizeof(stat_buf) - \
1875 strlen(stat_buf) - 2)
1879 INFOBIT(TIOCM_RTS, "|RTS");
1880 STATBIT(TIOCM_CTS, "|CTS");
1881 INFOBIT(TIOCM_DTR, "|DTR");
1882 STATBIT(TIOCM_DSR, "|DSR");
1883 STATBIT(TIOCM_CAR, "|CD");
1884 STATBIT(TIOCM_RNG, "|RI");
1888 seq_puts(m, stat_buf);
1894 mutex_unlock(&port->mutex);
1897 static int uart_proc_show(struct seq_file *m, void *v)
1899 struct tty_driver *ttydrv = m->private;
1900 struct uart_driver *drv = ttydrv->driver_state;
1903 seq_printf(m, "serinfo:1.0 driver%s%s revision:%s\n", "", "", "");
1904 for (i = 0; i < drv->nr; i++)
1905 uart_line_info(m, drv, i);
1910 static inline bool uart_console_enabled(struct uart_port *port)
1912 return uart_console(port) && (port->cons->flags & CON_ENABLED);
1915 static void uart_port_spin_lock_init(struct uart_port *port)
1917 spin_lock_init(&port->lock);
1918 lockdep_set_class(&port->lock, &port_lock_key);
1921 #if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(CONFIG_CONSOLE_POLL)
1923 * uart_console_write - write a console message to a serial port
1924 * @port: the port to write the message
1925 * @s: array of characters
1926 * @count: number of characters in string to write
1927 * @putchar: function to write character to port
1929 void uart_console_write(struct uart_port *port, const char *s,
1931 void (*putchar)(struct uart_port *, int))
1935 for (i = 0; i < count; i++, s++) {
1937 putchar(port, '\r');
1941 EXPORT_SYMBOL_GPL(uart_console_write);
1944 * Check whether an invalid uart number has been specified, and
1945 * if so, search for the first available port that does have
1948 struct uart_port * __init
1949 uart_get_console(struct uart_port *ports, int nr, struct console *co)
1951 int idx = co->index;
1953 if (idx < 0 || idx >= nr || (ports[idx].iobase == 0 &&
1954 ports[idx].membase == NULL))
1955 for (idx = 0; idx < nr; idx++)
1956 if (ports[idx].iobase != 0 ||
1957 ports[idx].membase != NULL)
1966 * uart_parse_earlycon - Parse earlycon options
1967 * @p: ptr to 2nd field (ie., just beyond '<name>,')
1968 * @iotype: ptr for decoded iotype (out)
1969 * @addr: ptr for decoded mapbase/iobase (out)
1970 * @options: ptr for <options> field; NULL if not present (out)
1972 * Decodes earlycon kernel command line parameters of the form
1973 * earlycon=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
1974 * console=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
1978 * earlycon=<name>,0x<addr>,<options>
1979 * console=<name>,0x<addr>,<options>
1981 * is also accepted; the returned @iotype will be UPIO_MEM.
1983 * Returns 0 on success or -EINVAL on failure
1985 int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
1988 if (strncmp(p, "mmio,", 5) == 0) {
1991 } else if (strncmp(p, "mmio16,", 7) == 0) {
1992 *iotype = UPIO_MEM16;
1994 } else if (strncmp(p, "mmio32,", 7) == 0) {
1995 *iotype = UPIO_MEM32;
1997 } else if (strncmp(p, "mmio32be,", 9) == 0) {
1998 *iotype = UPIO_MEM32BE;
2000 } else if (strncmp(p, "mmio32native,", 13) == 0) {
2001 *iotype = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) ?
2002 UPIO_MEM32BE : UPIO_MEM32;
2004 } else if (strncmp(p, "io,", 3) == 0) {
2005 *iotype = UPIO_PORT;
2007 } else if (strncmp(p, "0x", 2) == 0) {
2014 * Before you replace it with kstrtoull(), think about options separator
2015 * (',') it will not tolerate
2017 *addr = simple_strtoull(p, NULL, 0);
2025 EXPORT_SYMBOL_GPL(uart_parse_earlycon);
2028 * uart_parse_options - Parse serial port baud/parity/bits/flow control.
2029 * @options: pointer to option string
2030 * @baud: pointer to an 'int' variable for the baud rate.
2031 * @parity: pointer to an 'int' variable for the parity.
2032 * @bits: pointer to an 'int' variable for the number of data bits.
2033 * @flow: pointer to an 'int' variable for the flow control character.
2035 * uart_parse_options decodes a string containing the serial console
2036 * options. The format of the string is <baud><parity><bits><flow>,
2040 uart_parse_options(const char *options, int *baud, int *parity,
2041 int *bits, int *flow)
2043 const char *s = options;
2045 *baud = simple_strtoul(s, NULL, 10);
2046 while (*s >= '0' && *s <= '9')
2055 EXPORT_SYMBOL_GPL(uart_parse_options);
2058 * uart_set_options - setup the serial console parameters
2059 * @port: pointer to the serial ports uart_port structure
2060 * @co: console pointer
2062 * @parity: parity character - 'n' (none), 'o' (odd), 'e' (even)
2063 * @bits: number of data bits
2064 * @flow: flow control character - 'r' (rts)
2067 uart_set_options(struct uart_port *port, struct console *co,
2068 int baud, int parity, int bits, int flow)
2070 struct ktermios termios;
2071 static struct ktermios dummy;
2074 * Ensure that the serial-console lock is initialised early.
2076 * Note that the console-enabled check is needed because of kgdboc,
2077 * which can end up calling uart_set_options() for an already enabled
2078 * console via tty_find_polling_driver() and uart_poll_init().
2080 if (!uart_console_enabled(port) && !port->console_reinit)
2081 uart_port_spin_lock_init(port);
2083 memset(&termios, 0, sizeof(struct ktermios));
2085 termios.c_cflag |= CREAD | HUPCL | CLOCAL;
2086 tty_termios_encode_baud_rate(&termios, baud, baud);
2089 termios.c_cflag |= CS7;
2091 termios.c_cflag |= CS8;
2095 termios.c_cflag |= PARODD;
2098 termios.c_cflag |= PARENB;
2103 termios.c_cflag |= CRTSCTS;
2106 * some uarts on other side don't support no flow control.
2107 * So we set * DTR in host uart to make them happy
2109 port->mctrl |= TIOCM_DTR;
2111 port->ops->set_termios(port, &termios, &dummy);
2113 * Allow the setting of the UART parameters with a NULL console
2117 co->cflag = termios.c_cflag;
2118 co->ispeed = termios.c_ispeed;
2119 co->ospeed = termios.c_ospeed;
2124 EXPORT_SYMBOL_GPL(uart_set_options);
2125 #endif /* CONFIG_SERIAL_CORE_CONSOLE */
2128 * uart_change_pm - set power state of the port
2130 * @state: port descriptor
2131 * @pm_state: new state
2133 * Locking: port->mutex has to be held
2135 static void uart_change_pm(struct uart_state *state,
2136 enum uart_pm_state pm_state)
2138 struct uart_port *port = uart_port_check(state);
2140 if (state->pm_state != pm_state) {
2141 if (port && port->ops->pm)
2142 port->ops->pm(port, pm_state, state->pm_state);
2143 state->pm_state = pm_state;
2148 struct uart_port *port;
2149 struct uart_driver *driver;
2152 static int serial_match_port(struct device *dev, void *data)
2154 struct uart_match *match = data;
2155 struct tty_driver *tty_drv = match->driver->tty_driver;
2156 dev_t devt = MKDEV(tty_drv->major, tty_drv->minor_start) +
2159 return dev->devt == devt; /* Actually, only one tty per port */
2162 int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport)
2164 struct uart_state *state = drv->state + uport->line;
2165 struct tty_port *port = &state->port;
2166 struct device *tty_dev;
2167 struct uart_match match = {uport, drv};
2169 mutex_lock(&port->mutex);
2171 tty_dev = device_find_child(uport->dev, &match, serial_match_port);
2172 if (tty_dev && device_may_wakeup(tty_dev)) {
2173 enable_irq_wake(uport->irq);
2174 put_device(tty_dev);
2175 mutex_unlock(&port->mutex);
2178 put_device(tty_dev);
2180 /* Nothing to do if the console is not suspending */
2181 if (!console_suspend_enabled && uart_console(uport))
2184 uport->suspended = 1;
2186 if (tty_port_initialized(port)) {
2187 const struct uart_ops *ops = uport->ops;
2190 tty_port_set_suspended(port, 1);
2191 tty_port_set_initialized(port, 0);
2193 spin_lock_irq(&uport->lock);
2194 ops->stop_tx(uport);
2195 ops->set_mctrl(uport, 0);
2196 ops->stop_rx(uport);
2197 spin_unlock_irq(&uport->lock);
2200 * Wait for the transmitter to empty.
2202 for (tries = 3; !ops->tx_empty(uport) && tries; tries--)
2205 dev_err(uport->dev, "%s: Unable to drain transmitter\n",
2208 ops->shutdown(uport);
2212 * Disable the console device before suspending.
2214 if (uart_console(uport))
2215 console_stop(uport->cons);
2217 uart_change_pm(state, UART_PM_STATE_OFF);
2219 mutex_unlock(&port->mutex);
2224 int uart_resume_port(struct uart_driver *drv, struct uart_port *uport)
2226 struct uart_state *state = drv->state + uport->line;
2227 struct tty_port *port = &state->port;
2228 struct device *tty_dev;
2229 struct uart_match match = {uport, drv};
2230 struct ktermios termios;
2232 mutex_lock(&port->mutex);
2234 tty_dev = device_find_child(uport->dev, &match, serial_match_port);
2235 if (!uport->suspended && device_may_wakeup(tty_dev)) {
2236 if (irqd_is_wakeup_set(irq_get_irq_data((uport->irq))))
2237 disable_irq_wake(uport->irq);
2238 put_device(tty_dev);
2239 mutex_unlock(&port->mutex);
2242 put_device(tty_dev);
2243 uport->suspended = 0;
2246 * Re-enable the console device after suspending.
2248 if (uart_console(uport)) {
2250 * First try to use the console cflag setting.
2252 memset(&termios, 0, sizeof(struct ktermios));
2253 termios.c_cflag = uport->cons->cflag;
2254 termios.c_ispeed = uport->cons->ispeed;
2255 termios.c_ospeed = uport->cons->ospeed;
2258 * If that's unset, use the tty termios setting.
2260 if (port->tty && termios.c_cflag == 0)
2261 termios = port->tty->termios;
2263 if (console_suspend_enabled)
2264 uart_change_pm(state, UART_PM_STATE_ON);
2265 uport->ops->set_termios(uport, &termios, NULL);
2266 if (console_suspend_enabled)
2267 console_start(uport->cons);
2270 if (tty_port_suspended(port)) {
2271 const struct uart_ops *ops = uport->ops;
2274 uart_change_pm(state, UART_PM_STATE_ON);
2275 spin_lock_irq(&uport->lock);
2276 ops->set_mctrl(uport, 0);
2277 spin_unlock_irq(&uport->lock);
2278 if (console_suspend_enabled || !uart_console(uport)) {
2279 /* Protected by port mutex for now */
2280 struct tty_struct *tty = port->tty;
2282 ret = ops->startup(uport);
2285 uart_change_speed(tty, state, NULL);
2286 spin_lock_irq(&uport->lock);
2287 ops->set_mctrl(uport, uport->mctrl);
2288 ops->start_tx(uport);
2289 spin_unlock_irq(&uport->lock);
2290 tty_port_set_initialized(port, 1);
2293 * Failed to resume - maybe hardware went away?
2294 * Clear the "initialized" flag so we won't try
2295 * to call the low level drivers shutdown method.
2297 uart_shutdown(tty, state);
2301 tty_port_set_suspended(port, 0);
2304 mutex_unlock(&port->mutex);
2310 uart_report_port(struct uart_driver *drv, struct uart_port *port)
2314 switch (port->iotype) {
2316 snprintf(address, sizeof(address), "I/O 0x%lx", port->iobase);
2319 snprintf(address, sizeof(address),
2320 "I/O 0x%lx offset 0x%x", port->iobase, port->hub6);
2328 snprintf(address, sizeof(address),
2329 "MMIO 0x%llx", (unsigned long long)port->mapbase);
2332 strlcpy(address, "*unknown*", sizeof(address));
2336 pr_info("%s%s%s at %s (irq = %d, base_baud = %d) is a %s\n",
2337 port->dev ? dev_name(port->dev) : "",
2338 port->dev ? ": " : "",
2340 address, port->irq, port->uartclk / 16, uart_type(port));
2342 /* The magic multiplier feature is a bit obscure, so report it too. */
2343 if (port->flags & UPF_MAGIC_MULTIPLIER)
2344 pr_info("%s%s%s extra baud rates supported: %d, %d",
2345 port->dev ? dev_name(port->dev) : "",
2346 port->dev ? ": " : "",
2348 port->uartclk / 8, port->uartclk / 4);
2352 uart_configure_port(struct uart_driver *drv, struct uart_state *state,
2353 struct uart_port *port)
2358 * If there isn't a port here, don't do anything further.
2360 if (!port->iobase && !port->mapbase && !port->membase)
2364 * Now do the auto configuration stuff. Note that config_port
2365 * is expected to claim the resources and map the port for us.
2368 if (port->flags & UPF_AUTO_IRQ)
2369 flags |= UART_CONFIG_IRQ;
2370 if (port->flags & UPF_BOOT_AUTOCONF) {
2371 if (!(port->flags & UPF_FIXED_TYPE)) {
2372 port->type = PORT_UNKNOWN;
2373 flags |= UART_CONFIG_TYPE;
2375 port->ops->config_port(port, flags);
2378 if (port->type != PORT_UNKNOWN) {
2379 unsigned long flags;
2381 uart_report_port(drv, port);
2383 /* Power up port for set_mctrl() */
2384 uart_change_pm(state, UART_PM_STATE_ON);
2387 * Ensure that the modem control lines are de-activated.
2388 * keep the DTR setting that is set in uart_set_options()
2389 * We probably don't need a spinlock around this, but
2391 spin_lock_irqsave(&port->lock, flags);
2392 port->ops->set_mctrl(port, port->mctrl & TIOCM_DTR);
2393 spin_unlock_irqrestore(&port->lock, flags);
2396 * If this driver supports console, and it hasn't been
2397 * successfully registered yet, try to re-register it.
2398 * It may be that the port was not available.
2400 if (port->cons && !(port->cons->flags & CON_ENABLED))
2401 register_console(port->cons);
2404 * Power down all ports by default, except the
2405 * console if we have one.
2407 if (!uart_console(port))
2408 uart_change_pm(state, UART_PM_STATE_OFF);
2412 #ifdef CONFIG_CONSOLE_POLL
2414 static int uart_poll_init(struct tty_driver *driver, int line, char *options)
2416 struct uart_driver *drv = driver->driver_state;
2417 struct uart_state *state = drv->state + line;
2418 struct tty_port *tport;
2419 struct uart_port *port;
2426 tport = &state->port;
2427 mutex_lock(&tport->mutex);
2429 port = uart_port_check(state);
2430 if (!port || !(port->ops->poll_get_char && port->ops->poll_put_char)) {
2435 if (port->ops->poll_init) {
2437 * We don't set initialized as we only initialized the hw,
2438 * e.g. state->xmit is still uninitialized.
2440 if (!tty_port_initialized(tport))
2441 ret = port->ops->poll_init(port);
2444 if (!ret && options) {
2445 uart_parse_options(options, &baud, &parity, &bits, &flow);
2446 ret = uart_set_options(port, NULL, baud, parity, bits, flow);
2449 mutex_unlock(&tport->mutex);
2453 static int uart_poll_get_char(struct tty_driver *driver, int line)
2455 struct uart_driver *drv = driver->driver_state;
2456 struct uart_state *state = drv->state + line;
2457 struct uart_port *port;
2460 port = uart_port_ref(state);
2462 ret = port->ops->poll_get_char(port);
2463 uart_port_deref(port);
2469 static void uart_poll_put_char(struct tty_driver *driver, int line, char ch)
2471 struct uart_driver *drv = driver->driver_state;
2472 struct uart_state *state = drv->state + line;
2473 struct uart_port *port;
2475 port = uart_port_ref(state);
2480 port->ops->poll_put_char(port, '\r');
2481 port->ops->poll_put_char(port, ch);
2482 uart_port_deref(port);
2486 static const struct tty_operations uart_ops = {
2487 .install = uart_install,
2489 .close = uart_close,
2490 .write = uart_write,
2491 .put_char = uart_put_char,
2492 .flush_chars = uart_flush_chars,
2493 .write_room = uart_write_room,
2494 .chars_in_buffer= uart_chars_in_buffer,
2495 .flush_buffer = uart_flush_buffer,
2496 .ioctl = uart_ioctl,
2497 .throttle = uart_throttle,
2498 .unthrottle = uart_unthrottle,
2499 .send_xchar = uart_send_xchar,
2500 .set_termios = uart_set_termios,
2501 .set_ldisc = uart_set_ldisc,
2503 .start = uart_start,
2504 .hangup = uart_hangup,
2505 .break_ctl = uart_break_ctl,
2506 .wait_until_sent= uart_wait_until_sent,
2507 #ifdef CONFIG_PROC_FS
2508 .proc_show = uart_proc_show,
2510 .tiocmget = uart_tiocmget,
2511 .tiocmset = uart_tiocmset,
2512 .set_serial = uart_set_info_user,
2513 .get_serial = uart_get_info_user,
2514 .get_icount = uart_get_icount,
2515 #ifdef CONFIG_CONSOLE_POLL
2516 .poll_init = uart_poll_init,
2517 .poll_get_char = uart_poll_get_char,
2518 .poll_put_char = uart_poll_put_char,
2522 static const struct tty_port_operations uart_port_ops = {
2523 .carrier_raised = uart_carrier_raised,
2524 .dtr_rts = uart_dtr_rts,
2525 .activate = uart_port_activate,
2526 .shutdown = uart_tty_port_shutdown,
2530 * uart_register_driver - register a driver with the uart core layer
2531 * @drv: low level driver structure
2533 * Register a uart driver with the core driver. We in turn register
2534 * with the tty layer, and initialise the core driver per-port state.
2536 * We have a proc file in /proc/tty/driver which is named after the
2539 * drv->port should be NULL, and the per-port structures should be
2540 * registered using uart_add_one_port after this call has succeeded.
2542 int uart_register_driver(struct uart_driver *drv)
2544 struct tty_driver *normal;
2545 int i, retval = -ENOMEM;
2550 * Maybe we should be using a slab cache for this, especially if
2551 * we have a large number of ports to handle.
2553 drv->state = kcalloc(drv->nr, sizeof(struct uart_state), GFP_KERNEL);
2557 normal = tty_alloc_driver(drv->nr, TTY_DRIVER_REAL_RAW |
2558 TTY_DRIVER_DYNAMIC_DEV);
2559 if (IS_ERR(normal)) {
2560 retval = PTR_ERR(normal);
2564 drv->tty_driver = normal;
2566 normal->driver_name = drv->driver_name;
2567 normal->name = drv->dev_name;
2568 normal->major = drv->major;
2569 normal->minor_start = drv->minor;
2570 normal->type = TTY_DRIVER_TYPE_SERIAL;
2571 normal->subtype = SERIAL_TYPE_NORMAL;
2572 normal->init_termios = tty_std_termios;
2573 normal->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
2574 normal->init_termios.c_ispeed = normal->init_termios.c_ospeed = 9600;
2575 normal->driver_state = drv;
2576 tty_set_operations(normal, &uart_ops);
2579 * Initialise the UART state(s).
2581 for (i = 0; i < drv->nr; i++) {
2582 struct uart_state *state = drv->state + i;
2583 struct tty_port *port = &state->port;
2585 tty_port_init(port);
2586 port->ops = &uart_port_ops;
2589 retval = tty_register_driver(normal);
2593 for (i = 0; i < drv->nr; i++)
2594 tty_port_destroy(&drv->state[i].port);
2595 tty_driver_kref_put(normal);
2603 * uart_unregister_driver - remove a driver from the uart core layer
2604 * @drv: low level driver structure
2606 * Remove all references to a driver from the core driver. The low
2607 * level driver must have removed all its ports via the
2608 * uart_remove_one_port() if it registered them with uart_add_one_port().
2609 * (ie, drv->port == NULL)
2611 void uart_unregister_driver(struct uart_driver *drv)
2613 struct tty_driver *p = drv->tty_driver;
2616 tty_unregister_driver(p);
2617 tty_driver_kref_put(p);
2618 for (i = 0; i < drv->nr; i++)
2619 tty_port_destroy(&drv->state[i].port);
2622 drv->tty_driver = NULL;
2625 struct tty_driver *uart_console_device(struct console *co, int *index)
2627 struct uart_driver *p = co->data;
2629 return p->tty_driver;
2631 EXPORT_SYMBOL_GPL(uart_console_device);
2633 static ssize_t uartclk_show(struct device *dev,
2634 struct device_attribute *attr, char *buf)
2636 struct serial_struct tmp;
2637 struct tty_port *port = dev_get_drvdata(dev);
2639 uart_get_info(port, &tmp);
2640 return sprintf(buf, "%d\n", tmp.baud_base * 16);
2643 static ssize_t type_show(struct device *dev,
2644 struct device_attribute *attr, char *buf)
2646 struct serial_struct tmp;
2647 struct tty_port *port = dev_get_drvdata(dev);
2649 uart_get_info(port, &tmp);
2650 return sprintf(buf, "%d\n", tmp.type);
2653 static ssize_t line_show(struct device *dev,
2654 struct device_attribute *attr, char *buf)
2656 struct serial_struct tmp;
2657 struct tty_port *port = dev_get_drvdata(dev);
2659 uart_get_info(port, &tmp);
2660 return sprintf(buf, "%d\n", tmp.line);
2663 static ssize_t port_show(struct device *dev,
2664 struct device_attribute *attr, char *buf)
2666 struct serial_struct tmp;
2667 struct tty_port *port = dev_get_drvdata(dev);
2668 unsigned long ioaddr;
2670 uart_get_info(port, &tmp);
2672 if (HIGH_BITS_OFFSET)
2673 ioaddr |= (unsigned long)tmp.port_high << HIGH_BITS_OFFSET;
2674 return sprintf(buf, "0x%lX\n", ioaddr);
2677 static ssize_t irq_show(struct device *dev,
2678 struct device_attribute *attr, char *buf)
2680 struct serial_struct tmp;
2681 struct tty_port *port = dev_get_drvdata(dev);
2683 uart_get_info(port, &tmp);
2684 return sprintf(buf, "%d\n", tmp.irq);
2687 static ssize_t flags_show(struct device *dev,
2688 struct device_attribute *attr, char *buf)
2690 struct serial_struct tmp;
2691 struct tty_port *port = dev_get_drvdata(dev);
2693 uart_get_info(port, &tmp);
2694 return sprintf(buf, "0x%X\n", tmp.flags);
2697 static ssize_t xmit_fifo_size_show(struct device *dev,
2698 struct device_attribute *attr, char *buf)
2700 struct serial_struct tmp;
2701 struct tty_port *port = dev_get_drvdata(dev);
2703 uart_get_info(port, &tmp);
2704 return sprintf(buf, "%d\n", tmp.xmit_fifo_size);
2707 static ssize_t close_delay_show(struct device *dev,
2708 struct device_attribute *attr, char *buf)
2710 struct serial_struct tmp;
2711 struct tty_port *port = dev_get_drvdata(dev);
2713 uart_get_info(port, &tmp);
2714 return sprintf(buf, "%d\n", tmp.close_delay);
2717 static ssize_t closing_wait_show(struct device *dev,
2718 struct device_attribute *attr, char *buf)
2720 struct serial_struct tmp;
2721 struct tty_port *port = dev_get_drvdata(dev);
2723 uart_get_info(port, &tmp);
2724 return sprintf(buf, "%d\n", tmp.closing_wait);
2727 static ssize_t custom_divisor_show(struct device *dev,
2728 struct device_attribute *attr, char *buf)
2730 struct serial_struct tmp;
2731 struct tty_port *port = dev_get_drvdata(dev);
2733 uart_get_info(port, &tmp);
2734 return sprintf(buf, "%d\n", tmp.custom_divisor);
2737 static ssize_t io_type_show(struct device *dev,
2738 struct device_attribute *attr, char *buf)
2740 struct serial_struct tmp;
2741 struct tty_port *port = dev_get_drvdata(dev);
2743 uart_get_info(port, &tmp);
2744 return sprintf(buf, "%d\n", tmp.io_type);
2747 static ssize_t iomem_base_show(struct device *dev,
2748 struct device_attribute *attr, char *buf)
2750 struct serial_struct tmp;
2751 struct tty_port *port = dev_get_drvdata(dev);
2753 uart_get_info(port, &tmp);
2754 return sprintf(buf, "0x%lX\n", (unsigned long)tmp.iomem_base);
2757 static ssize_t iomem_reg_shift_show(struct device *dev,
2758 struct device_attribute *attr, char *buf)
2760 struct serial_struct tmp;
2761 struct tty_port *port = dev_get_drvdata(dev);
2763 uart_get_info(port, &tmp);
2764 return sprintf(buf, "%d\n", tmp.iomem_reg_shift);
2767 static ssize_t console_show(struct device *dev,
2768 struct device_attribute *attr, char *buf)
2770 struct tty_port *port = dev_get_drvdata(dev);
2771 struct uart_state *state = container_of(port, struct uart_state, port);
2772 struct uart_port *uport;
2773 bool console = false;
2775 mutex_lock(&port->mutex);
2776 uport = uart_port_check(state);
2778 console = uart_console_enabled(uport);
2779 mutex_unlock(&port->mutex);
2781 return sprintf(buf, "%c\n", console ? 'Y' : 'N');
2784 static ssize_t console_store(struct device *dev,
2785 struct device_attribute *attr, const char *buf, size_t count)
2787 struct tty_port *port = dev_get_drvdata(dev);
2788 struct uart_state *state = container_of(port, struct uart_state, port);
2789 struct uart_port *uport;
2790 bool oldconsole, newconsole;
2793 ret = kstrtobool(buf, &newconsole);
2797 mutex_lock(&port->mutex);
2798 uport = uart_port_check(state);
2800 oldconsole = uart_console_enabled(uport);
2801 if (oldconsole && !newconsole) {
2802 ret = unregister_console(uport->cons);
2803 } else if (!oldconsole && newconsole) {
2804 if (uart_console(uport)) {
2805 uport->console_reinit = 1;
2806 register_console(uport->cons);
2814 mutex_unlock(&port->mutex);
2816 return ret < 0 ? ret : count;
2819 static DEVICE_ATTR_RO(uartclk);
2820 static DEVICE_ATTR_RO(type);
2821 static DEVICE_ATTR_RO(line);
2822 static DEVICE_ATTR_RO(port);
2823 static DEVICE_ATTR_RO(irq);
2824 static DEVICE_ATTR_RO(flags);
2825 static DEVICE_ATTR_RO(xmit_fifo_size);
2826 static DEVICE_ATTR_RO(close_delay);
2827 static DEVICE_ATTR_RO(closing_wait);
2828 static DEVICE_ATTR_RO(custom_divisor);
2829 static DEVICE_ATTR_RO(io_type);
2830 static DEVICE_ATTR_RO(iomem_base);
2831 static DEVICE_ATTR_RO(iomem_reg_shift);
2832 static DEVICE_ATTR_RW(console);
2834 static struct attribute *tty_dev_attrs[] = {
2835 &dev_attr_uartclk.attr,
2836 &dev_attr_type.attr,
2837 &dev_attr_line.attr,
2838 &dev_attr_port.attr,
2840 &dev_attr_flags.attr,
2841 &dev_attr_xmit_fifo_size.attr,
2842 &dev_attr_close_delay.attr,
2843 &dev_attr_closing_wait.attr,
2844 &dev_attr_custom_divisor.attr,
2845 &dev_attr_io_type.attr,
2846 &dev_attr_iomem_base.attr,
2847 &dev_attr_iomem_reg_shift.attr,
2848 &dev_attr_console.attr,
2852 static const struct attribute_group tty_dev_attr_group = {
2853 .attrs = tty_dev_attrs,
2857 * uart_add_one_port - attach a driver-defined port structure
2858 * @drv: pointer to the uart low level driver structure for this port
2859 * @uport: uart port structure to use for this port.
2861 * Context: task context, might sleep
2863 * This allows the driver to register its own uart_port structure
2864 * with the core driver. The main purpose is to allow the low
2865 * level uart drivers to expand uart_port, rather than having yet
2866 * more levels of structures.
2868 int uart_add_one_port(struct uart_driver *drv, struct uart_port *uport)
2870 struct uart_state *state;
2871 struct tty_port *port;
2873 struct device *tty_dev;
2876 if (uport->line >= drv->nr)
2879 state = drv->state + uport->line;
2880 port = &state->port;
2882 mutex_lock(&port_mutex);
2883 mutex_lock(&port->mutex);
2884 if (state->uart_port) {
2889 /* Link the port to the driver state table and vice versa */
2890 atomic_set(&state->refcount, 1);
2891 init_waitqueue_head(&state->remove_wait);
2892 state->uart_port = uport;
2893 uport->state = state;
2895 state->pm_state = UART_PM_STATE_UNDEFINED;
2896 uport->cons = drv->cons;
2897 uport->minor = drv->tty_driver->minor_start + uport->line;
2898 uport->name = kasprintf(GFP_KERNEL, "%s%d", drv->dev_name,
2899 drv->tty_driver->name_base + uport->line);
2906 * If this port is in use as a console then the spinlock is already
2909 if (!uart_console_enabled(uport))
2910 uart_port_spin_lock_init(uport);
2912 if (uport->cons && uport->dev)
2913 of_console_check(uport->dev->of_node, uport->cons->name, uport->line);
2915 tty_port_link_device(port, drv->tty_driver, uport->line);
2916 uart_configure_port(drv, state, uport);
2918 port->console = uart_console(uport);
2921 if (uport->attr_group)
2924 uport->tty_groups = kcalloc(num_groups, sizeof(*uport->tty_groups),
2926 if (!uport->tty_groups) {
2930 uport->tty_groups[0] = &tty_dev_attr_group;
2931 if (uport->attr_group)
2932 uport->tty_groups[1] = uport->attr_group;
2935 * Register the port whether it's detected or not. This allows
2936 * setserial to be used to alter this port's parameters.
2938 tty_dev = tty_port_register_device_attr_serdev(port, drv->tty_driver,
2939 uport->line, uport->dev, port, uport->tty_groups);
2940 if (!IS_ERR(tty_dev)) {
2941 device_set_wakeup_capable(tty_dev, 1);
2943 dev_err(uport->dev, "Cannot register tty device on line %d\n",
2948 * Ensure UPF_DEAD is not set.
2950 uport->flags &= ~UPF_DEAD;
2953 mutex_unlock(&port->mutex);
2954 mutex_unlock(&port_mutex);
2960 * uart_remove_one_port - detach a driver defined port structure
2961 * @drv: pointer to the uart low level driver structure for this port
2962 * @uport: uart port structure for this port
2964 * Context: task context, might sleep
2966 * This unhooks (and hangs up) the specified port structure from the
2967 * core driver. No further calls will be made to the low-level code
2970 int uart_remove_one_port(struct uart_driver *drv, struct uart_port *uport)
2972 struct uart_state *state = drv->state + uport->line;
2973 struct tty_port *port = &state->port;
2974 struct uart_port *uart_port;
2975 struct tty_struct *tty;
2978 mutex_lock(&port_mutex);
2981 * Mark the port "dead" - this prevents any opens from
2982 * succeeding while we shut down the port.
2984 mutex_lock(&port->mutex);
2985 uart_port = uart_port_check(state);
2986 if (uart_port != uport)
2987 dev_alert(uport->dev, "Removing wrong port: %p != %p\n",
2991 mutex_unlock(&port->mutex);
2995 uport->flags |= UPF_DEAD;
2996 mutex_unlock(&port->mutex);
2999 * Remove the devices from the tty layer
3001 tty_port_unregister_device(port, drv->tty_driver, uport->line);
3003 tty = tty_port_tty_get(port);
3005 tty_vhangup(port->tty);
3010 * If the port is used as a console, unregister it
3012 if (uart_console(uport))
3013 unregister_console(uport->cons);
3016 * Free the port IO and memory resources, if any.
3018 if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
3019 uport->ops->release_port(uport);
3020 kfree(uport->tty_groups);
3024 * Indicate that there isn't a port here anymore.
3026 uport->type = PORT_UNKNOWN;
3028 mutex_lock(&port->mutex);
3029 WARN_ON(atomic_dec_return(&state->refcount) < 0);
3030 wait_event(state->remove_wait, !atomic_read(&state->refcount));
3031 state->uart_port = NULL;
3032 mutex_unlock(&port->mutex);
3034 mutex_unlock(&port_mutex);
3040 * Are the two ports equivalent?
3042 bool uart_match_port(const struct uart_port *port1,
3043 const struct uart_port *port2)
3045 if (port1->iotype != port2->iotype)
3048 switch (port1->iotype) {
3050 return port1->iobase == port2->iobase;
3052 return port1->iobase == port2->iobase &&
3053 port1->hub6 == port2->hub6;
3060 return port1->mapbase == port2->mapbase;
3065 EXPORT_SYMBOL(uart_match_port);
3068 * uart_handle_dcd_change - handle a change of carrier detect state
3069 * @uport: uart_port structure for the open port
3070 * @status: new carrier detect status, nonzero if active
3072 * Caller must hold uport->lock
3074 void uart_handle_dcd_change(struct uart_port *uport, unsigned int status)
3076 struct tty_port *port = &uport->state->port;
3077 struct tty_struct *tty = port->tty;
3078 struct tty_ldisc *ld;
3080 lockdep_assert_held_once(&uport->lock);
3083 ld = tty_ldisc_ref(tty);
3085 if (ld->ops->dcd_change)
3086 ld->ops->dcd_change(tty, status);
3087 tty_ldisc_deref(ld);
3091 uport->icount.dcd++;
3093 if (uart_dcd_enabled(uport)) {
3095 wake_up_interruptible(&port->open_wait);
3100 EXPORT_SYMBOL_GPL(uart_handle_dcd_change);
3103 * uart_handle_cts_change - handle a change of clear-to-send state
3104 * @uport: uart_port structure for the open port
3105 * @status: new clear to send status, nonzero if active
3107 * Caller must hold uport->lock
3109 void uart_handle_cts_change(struct uart_port *uport, unsigned int status)
3111 lockdep_assert_held_once(&uport->lock);
3113 uport->icount.cts++;
3115 if (uart_softcts_mode(uport)) {
3116 if (uport->hw_stopped) {
3118 uport->hw_stopped = 0;
3119 uport->ops->start_tx(uport);
3120 uart_write_wakeup(uport);
3124 uport->hw_stopped = 1;
3125 uport->ops->stop_tx(uport);
3131 EXPORT_SYMBOL_GPL(uart_handle_cts_change);
3134 * uart_insert_char - push a char to the uart layer
3136 * User is responsible to call tty_flip_buffer_push when they are done with
3139 * @port: corresponding port
3140 * @status: state of the serial port RX buffer (LSR for 8250)
3141 * @overrun: mask of overrun bits in @status
3142 * @ch: character to push
3143 * @flag: flag for the character (see TTY_NORMAL and friends)
3145 void uart_insert_char(struct uart_port *port, unsigned int status,
3146 unsigned int overrun, unsigned int ch, unsigned int flag)
3148 struct tty_port *tport = &port->state->port;
3150 if ((status & port->ignore_status_mask & ~overrun) == 0)
3151 if (tty_insert_flip_char(tport, ch, flag) == 0)
3152 ++port->icount.buf_overrun;
3155 * Overrun is special. Since it's reported immediately,
3156 * it doesn't affect the current character.
3158 if (status & ~port->ignore_status_mask & overrun)
3159 if (tty_insert_flip_char(tport, 0, TTY_OVERRUN) == 0)
3160 ++port->icount.buf_overrun;
3162 EXPORT_SYMBOL_GPL(uart_insert_char);
3164 #ifdef CONFIG_MAGIC_SYSRQ_SERIAL
3165 static const char sysrq_toggle_seq[] = CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE;
3167 static void uart_sysrq_on(struct work_struct *w)
3169 int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq);
3171 sysrq_toggle_support(1);
3172 pr_info("SysRq is enabled by magic sequence '%*pE' on serial\n",
3173 sysrq_toggle_seq_len, sysrq_toggle_seq);
3175 static DECLARE_WORK(sysrq_enable_work, uart_sysrq_on);
3178 * uart_try_toggle_sysrq - Enables SysRq from serial line
3179 * @port: uart_port structure where char(s) after BREAK met
3180 * @ch: new character in the sequence after received BREAK
3182 * Enables magic SysRq when the required sequence is met on port
3183 * (see CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE).
3185 * Returns false if @ch is out of enabling sequence and should be
3186 * handled some other way, true if @ch was consumed.
3188 bool uart_try_toggle_sysrq(struct uart_port *port, unsigned int ch)
3190 int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq);
3192 if (!sysrq_toggle_seq_len)
3195 BUILD_BUG_ON(ARRAY_SIZE(sysrq_toggle_seq) >= U8_MAX);
3196 if (sysrq_toggle_seq[port->sysrq_seq] != ch) {
3197 port->sysrq_seq = 0;
3201 if (++port->sysrq_seq < sysrq_toggle_seq_len) {
3202 port->sysrq = jiffies + SYSRQ_TIMEOUT;
3206 schedule_work(&sysrq_enable_work);
3211 EXPORT_SYMBOL_GPL(uart_try_toggle_sysrq);
3214 EXPORT_SYMBOL(uart_write_wakeup);
3215 EXPORT_SYMBOL(uart_register_driver);
3216 EXPORT_SYMBOL(uart_unregister_driver);
3217 EXPORT_SYMBOL(uart_suspend_port);
3218 EXPORT_SYMBOL(uart_resume_port);
3219 EXPORT_SYMBOL(uart_add_one_port);
3220 EXPORT_SYMBOL(uart_remove_one_port);
3223 * uart_get_rs485_mode() - retrieve rs485 properties for given uart
3224 * @port: uart device's target port
3226 * This function implements the device tree binding described in
3227 * Documentation/devicetree/bindings/serial/rs485.txt.
3229 int uart_get_rs485_mode(struct uart_port *port)
3231 struct serial_rs485 *rs485conf = &port->rs485;
3232 struct device *dev = port->dev;
3236 ret = device_property_read_u32_array(dev, "rs485-rts-delay",
3239 rs485conf->delay_rts_before_send = rs485_delay[0];
3240 rs485conf->delay_rts_after_send = rs485_delay[1];
3242 rs485conf->delay_rts_before_send = 0;
3243 rs485conf->delay_rts_after_send = 0;
3247 * Clear full-duplex and enabled flags, set RTS polarity to active high
3248 * to get to a defined state with the following properties:
3250 rs485conf->flags &= ~(SER_RS485_RX_DURING_TX | SER_RS485_ENABLED |
3251 SER_RS485_TERMINATE_BUS |
3252 SER_RS485_RTS_AFTER_SEND);
3253 rs485conf->flags |= SER_RS485_RTS_ON_SEND;
3255 if (device_property_read_bool(dev, "rs485-rx-during-tx"))
3256 rs485conf->flags |= SER_RS485_RX_DURING_TX;
3258 if (device_property_read_bool(dev, "linux,rs485-enabled-at-boot-time"))
3259 rs485conf->flags |= SER_RS485_ENABLED;
3261 if (device_property_read_bool(dev, "rs485-rts-active-low")) {
3262 rs485conf->flags &= ~SER_RS485_RTS_ON_SEND;
3263 rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
3267 * Disabling termination by default is the safe choice: Else if many
3268 * bus participants enable it, no communication is possible at all.
3269 * Works fine for short cables and users may enable for longer cables.
3271 port->rs485_term_gpio = devm_gpiod_get_optional(dev, "rs485-term",
3273 if (IS_ERR(port->rs485_term_gpio)) {
3274 ret = PTR_ERR(port->rs485_term_gpio);
3275 port->rs485_term_gpio = NULL;
3276 return dev_err_probe(dev, ret, "Cannot get rs485-term-gpios\n");
3281 EXPORT_SYMBOL_GPL(uart_get_rs485_mode);
3283 MODULE_DESCRIPTION("Serial driver core");
3284 MODULE_LICENSE("GPL");